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Sample records for radiation dose estimates

  1. Radiation dose estimates for radiopharmaceuticals

    SciTech Connect

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

    1996-04-01

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

  2. Radiation Dose Estimation by Automated Cytogenetic Biodosimetry.

    PubMed

    Rogan, Peter K; Li, Yanxin; Wilkins, Ruth C; Flegal, Farrah N; Knoll, Joan H M

    2016-12-01

    The dose from ionizing radiation exposure can be interpolated from a calibration curve fit to the frequency of dicentric chromosomes (DCs) at multiple doses. As DC counts are manually determined, there is an acute need for accurate, fully automated biodosimetry calibration curve generation and analysis of exposed samples. Software, the Automated Dicentric Chromosome Identifier (ADCI), is presented which detects and discriminates DCs from monocentric chromosomes, computes biodosimetry calibration curves and estimates radiation dose. Images of metaphase cells from samples, exposed at 1.4-3.4 Gy, that had been manually scored by two reference laboratories were reanalyzed with ADCI. This resulted in estimated exposures within 0.4-1.1 Gy of the physical dose. Therefore, ADCI can determine radiation dose with accuracies comparable to standard triage biodosimetry. Calibration curves were generated from metaphase images in ~10 h, and dose estimations required ~0.8 h per 500 image sample. Running multiple instances of ADCI may be an effective response to a mass casualty radiation event. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Estimated radiation dose from timepieces containing tritium

    SciTech Connect

    McDowell-Boyer, L M

    1980-01-01

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

  4. Dose estimation software for radiation biodosimetry.

    PubMed

    Ainsbury, Elizabeth A; Lloyd, David C

    2010-02-01

    Cytogenetic analysis of chromosome damage in blood lymphocytes is widely used for radiation biodosimetry. Mathematical and statistical analysis is extremely important for accurate assessment of the data and results, and there are a number of classical statistical methods which are routinely employed. However, the large number of different mathematical techniques, the dependence of the models on certain statistical principles, and the complexity of some of the methods can lead to errors in data analysis and thus misinterpretation of results. Cytogenetic dose estimation software has been developed to address these problems by simplifying mathematical and statistical analysis of the cytogenetic data. "Dose Estimate" is a collection of mathematical and statistical methods based on the cytogenetic methods that are used for biodosimetry at the Health Protection Agency and elsewhere in the radiation cytogenetics community. Details of the biological and mathematical tools incorporated into the software are presented. Preliminary testing has been carried out, and the results demonstrate the accuracy and usefulness of the software in its current form. Proposals for improving the software through implementation of recently published Bayesian analysis techniques for cytogenetics are also outlined. An evaluation copy of the software is available on request from the authors.

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

    PubMed

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

    2016-06-01

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

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

    SciTech Connect

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

    1985-01-01

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

  7. Occupational radiation dose estimation for Finnish aircraft cabin attendants.

    PubMed

    Kojo, Katja; Aspholm, Rafael; Auvinen, Anssi

    2004-04-01

    The objective of this study was to develop a method for assessing dose radiation on the basis of individual flight history and to estimate whether this method is applicable for cabin attendants without flight log data. Questionnaire data were collected to determine attendants' flight history covering up to three decades. Finnair timetables and an expert panel of pilots were used to determine one to four representative flights in five route categories. The cumulative career and annual doses were calculated on the basis of the flight histories and route-specific exposure data. Questionnaire data were obtained from 544 flight attendants. The mean number of active workyears was 10.5 (range 0-30) years, and the mean cosmic radiation dose was 3.2 (range 0-9.5) mSv per active workyear. The mean cumulative career dose for all the cabin attendants was 34.0 (range 0-156.8) mSv. If no flight log data are available, survey data are needed for individual dose estimation when possible radiation effects on cabin crew are evaluated in epidemiologic studies. This method provides a crude procedure for assessing cosmic radiation exposure among attendants when survey data are missing.

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

    USGS Publications Warehouse

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

    2005-01-01

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

  9. Methods for estimating radiation doses received by commercial aircrew.

    PubMed

    Lantos, Pierre; Fuller, Nicolas; Bottollier-Depois, Jean-François

    2003-07-01

    Radiation doses received onboard aircraft are monitored in Europe to protect aircrew in accordance with a European Union directive. The French Aviation Authorities have developed a system called SIEVERT, using calculation codes to monitor effective radiation doses. For the galactic cosmic ray component, a 3-D world map of effective dose rates is computed using available operational codes. Detailed flight plans are used to ensure sufficient precision. For the solar particle event component, a semi-empirical model called SiGLE has been developed to calculate a time-dependent map of effective dose rates in the course of the event. SiGLE is based on particle transport code results and measurements during solar particle events onboard Concorde airplanes. We present a comparison of the calculated effective radiation dose and measured dose equivalent for various flights onboard Air France aircraft. The agreement is within 15%, which is about the precision of the state-of-the-art dosimetric measurements. Meteorological effects on the dose calculation appear to be negligible. Preliminary results based on solar particle events observed since 1942 with ionization chambers and neutron monitors are given. The present analysis shows that for the galactic cosmic ray component, monthly world maps based on neutron monitor observations are sufficient to ensure a precision of about 20% on the dose estimate for each flight. For the past 40 yr, according to the model SiGLE, none of the solar events has given an effective radiation dose larger than 1 mSv for flights on the most exposed routes.

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

    PubMed

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

    1990-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

    The dose and dose-equivalent estimates that astronauts might be expected to receive in space were assessed for the development of new radiation protection guidelines, considering several space mission scenarios. These scenarios included a 90-day LEO mission at 450 km altitude with orbital inclinations appropriate for NASA's Space Station (28.5, 57, and 90 deg), a 15-day sortie to GEO, and a 90-day lunar mission. All the missions contemplated would present space travelers with dose equivalents between 5 and 10 rem to the blood-forming organs, assuming no encounter with a large solar particle event; a large particle event could add considerable exposure for all scenarios except for the one at 28.5 orbital inclination. Adequate shielding must be included to guard against the radiation produced by such events.

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

    PubMed

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

    1986-01-01

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

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

    SciTech Connect

    Akkurt, Hatice; Eckerman, Keith F

    2007-01-01

    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.

  14. Radiation Dose Estimation for Pediatric Patients Undergoing Cardiac Catheterization

    NASA Astrophysics Data System (ADS)

    Wang, Chu

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

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

    SciTech Connect

    Loewe, W.E.

    1986-12-01

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

  16. Recent Updates to Radiation Organ Dose Estimation Tool PIMAL

    SciTech Connect

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

    2011-01-01

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

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

    PubMed

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

    2004-09-01

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

  18. Radiation Dose Estimation Using Realistic Postures with PIMAL

    SciTech Connect

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

    2010-01-01

    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.

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-09-28

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  2. CT Radiation Dose Optimization and Estimation: an Update for Radiologists

    PubMed Central

    2012-01-01

    In keeping with the increasing utilization of CT examinations, the greater concern about radiation hazards from examinations has been addressed. In this regard, CT radiation dose optimization has been given a great deal of attention by radiologists, referring physicians, technologists, and physicists. Dose-saving strategies are continuously evolving in terms of imaging techniques as well as dose management. Consequently, regular updates of this issue are necessary especially for radiologists who play a pivotal role in this activity. This review article will provide an update on how we can optimize CT dose in order to maximize the benefit-to-risk ratio of this clinically useful diagnostic imaging method. PMID:22247630

  3. CT radiation dose optimization and estimation: an update for radiologists.

    PubMed

    Goo, Hyun Woo

    2012-01-01

    In keeping with the increasing utilization of CT examinations, the greater concern about radiation hazards from examinations has been addressed. In this regard, CT radiation dose optimization has been given a great deal of attention by radiologists, referring physicians, technologists, and physicists. Dose-saving strategies are continuously evolving in terms of imaging techniques as well as dose management. Consequently, regular updates of this issue are necessary especially for radiologists who play a pivotal role in this activity. This review article will provide an update on how we can optimize CT dose in order to maximize the benefit-to-risk ratio of this clinically useful diagnostic imaging method.

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  6. Radiation absorbed dose estimates for 18F-BPA PET.

    PubMed

    Kono, Yuzuru; Kurihara, Hiroaki; Kawamoto, Hiroshi; Yasui, Naoko; Honda, Naoki; Igaki, Hiroshi; Itami, Jun

    2017-01-01

    Background Boron neutron capture therapy (BNCT) is a molecular radiation therapy approach based on the (10)B (n, α) (7)Li nuclear reaction in cancer cells. In BNCT, delivery of (10)B in the form of 4-borono-phenylalanine conjugated with fructose (BPA-fr) to the cancer cells is important. The PET tracer 4-borono-2-18F-fluoro-phenylalanine (FBPA) has been used to predict the accumulation of BPA-fr before BNCT. Purpose To determine the biodistribution and dosimetric parameters in 18F-BPA PET/CT studies. Material and Methods Human biokinetic data were obtained during clinical 18F-BPA PET studies between February and June 2015 at one institution. Nine consecutive patients were studied prospectively. The internal radiation dose was calculated on the basis of radioactivity data from blood, urine, and normal tissue of the heart, liver, spleen, kidney, and other parts of the body at each time point using OLINDA/EXM1.1 program. We compared our calculations with published 18F-FDG data. Results Adult patients (3 men, 3 women; age range, 28-68 years) had significantly smaller absorbed doses than pediatric patients (3 patients; age range, 5-12 years) ( P = 0.003). The mean effective dose was 57% lower in adult patients compared with pediatric patients. Mean effective doses for 18F-BPA were 25% lower than those for 18F-FDG presented in International Commission of Radiation Protection (ICRP) publication 106. Conclusion We found significant differences in organ absorbed doses for 18F-BPA against those for 18F-FDG presented in ICRP publication 106. Mean effective doses for 18F-BPA were smaller than those for 18F-FDG in the publication by 0.5-38% (mean difference, 25%).

  7. Space radiation dose estimates on the surface of Mars

    NASA Technical Reports Server (NTRS)

    Simonsen, Lisa C.; Nealy, John E.; Townsend, Lawrence W.; Wilson, John W.

    1990-01-01

    The Langley cosmic ray transport code and the Langley nucleon transport code (BRYNTRN) are used to quantify the transport and attenuation of galactic cosmic rays (GCR) and solar proton flares through the Martian atmosphere. Surface doses are estimated using both a low density and a high density carbon dioxide model of the atmosphere which, in the vertical direction, provides a total of 16 g/sq cm and 22 g/sq cm of protection, respectively. At the Mars surface during the solar minimum cycle, a blood-forming organ (BFO) dose equivalent of 10.5 to 12 rem/yr due to galactic cosmic ray transport and attenuation is calculated. Estimates of the BFO dose equivalents which would have been incurred from the three large solar flare events of August 1972, November 1960, and February 1956 are also calculated at the surface. Results indicate surface BFO dose equivalents of approximately 2 to 5, 5 to 7, and 8 to 10 rem per event, respectively. Doses are also estimated at altitudes up to 12 km above the Martian surface where the atmosphere will provide less total protection.

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

    PubMed Central

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

    2015-01-01

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

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

    SciTech Connect

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

    2010-12-23

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

  10. Optimizing CT radiation dose based on patient size and image quality: the size-specific dose estimate method.

    PubMed

    Larson, David B

    2014-10-01

    The principle of ALARA (dose as low as reasonably achievable) calls for dose optimization rather than dose reduction, per se. Optimization of CT radiation dose is accomplished by producing images of acceptable diagnostic image quality using the lowest dose method available. Because it is image quality that constrains the dose, CT dose optimization is primarily a problem of image quality rather than radiation dose. Therefore, the primary focus in CT radiation dose optimization should be on image quality. However, no reliable direct measure of image quality has been developed for routine clinical practice. Until such measures become available, size-specific dose estimates (SSDE) can be used as a reasonable image-quality estimate. The SSDE method of radiation dose optimization for CT abdomen and pelvis consists of plotting SSDE for a sample of examinations as a function of patient size, establishing an SSDE threshold curve based on radiologists' assessment of image quality, and modifying protocols to consistently produce doses that are slightly above the threshold SSDE curve. Challenges in operationalizing CT radiation dose optimization include data gathering and monitoring, managing the complexities of the numerous protocols, scanners and operators, and understanding the relationship of the automated tube current modulation (ATCM) parameters to image quality. Because CT manufacturers currently maintain their ATCM algorithms as secret for proprietary reasons, prospective modeling of SSDE for patient populations is not possible without reverse engineering the ATCM algorithm and, hence, optimization by this method requires a trial-and-error approach.

  11. RADIANCE: An automated, enterprise-wide solution for archiving and reporting CT radiation dose estimates.

    PubMed

    Cook, Tessa S; Zimmerman, Stefan L; Steingall, Scott R; Maidment, Andrew D A; Kim, Woojin; Boonn, William W

    2011-01-01

    There is growing interest in the ability to monitor, track, and report exposure to radiation from medical imaging. Historically, however, dose information has been stored on an image-based dose sheet, an arrangement that precludes widespread indexing. Although scanner manufacturers are beginning to include dose-related parameters in the Digital Imaging and Communications in Medicine (DICOM) headers of imaging studies, there remains a vast repository of retrospective computed tomographic (CT) data with image-based dose sheets. Consequently, it is difficult for imaging centers to monitor their dose estimates or participate in the American College of Radiology (ACR) Dose Index Registry. An automated extraction software pipeline known as Radiation Dose Intelligent Analytics for CT Examinations (RADIANCE) has been designed that quickly and accurately parses CT dose sheets to extract and archive dose-related parameters. Optical character recognition of information in the dose sheet leads to creation of a text file, which along with the DICOM study header is parsed to extract dose-related data. The data are then stored in a relational database that can be queried for dose monitoring and report creation. RADIANCE allows efficient dose analysis of CT examinations and more effective education of technologists, radiologists, and referring physicians regarding patient exposure to radiation at CT. RADIANCE also allows compliance with the ACR's dose reporting guidelines and greater awareness of patient radiation dose, ultimately resulting in improved patient care and treatment.

  12. Estimation of organ dose equivalents from residents of radiation-contaminated buildings with Rando phantom measurements.

    PubMed

    Lee, J S; Dong, S L; Wu, T H

    1999-05-01

    Since August 1996, a dose reconstruction model has been conducted with thermoluminescent dosimeter (TLD)-embedded chains, belts and badges for external dose measurements on the residents in radiation-contaminated buildings. The TLD dosimeters, worn on the front of the torso, would not be adequate for dose measurement in cases when the radiation is anisotropic or the incident angles of radiation sources are not directed in the front-to-back direction. The shielding and attenuation by the body would result in the dose equivalent estimation being somewhat skewed. An organ dose estimation method with a Rando phantom under various exposure geometries is proposed. The conversion factors, obtained from the phantom study, may be applicable to organ dose estimations for residents in the contaminated buildings if the incident angles correspond to the phantom simulation results. There is a great demand for developing a mathematical model or Monte Carlo calculation to deal with complicated indoor layout geometry problems involving ionizing radiation. Further research should be directed toward conducting laboratory simulation by investigating the relationship between doses delivered from multiple radiation sources. It is also necessary to collaborate with experimental biological dosimetry, such as chromosome aberration analysis, fluorescence in situ hybridization (FISH) and retrospective ESR-dosimetry with teeth, applied to the residents, so that the organ dose equivalent estimations may be more reliable for radio-epidemiological studies.

  13. Comprehensive assessment of radiation dose estimates for the CORE320 study.

    PubMed

    Rybicki, Frank J; Mather, Richard T; Kumamaru, Kanako K; Brinker, Jeffrey; Chen, Marcus Y; Cox, Christopher; Matheson, Matthew B; Dewey, Marc; DiCarli, Marcelo F; Miller, Julie M; Geleijns, Jacob; George, Richard T; Paul, Narinder; Texter, John; Vavere, Andrea; Yaw, Tan Swee; Lima, Joao A C; Clouse, Melvin E

    2015-01-01

    OBJECTIVE. The purpose of this study was to comprehensively study estimated radiation doses for subjects included in the main analysis of the Combined Non-invasive Coronary Angiography and Myocardial Perfusion Imaging Using 320 Detector Computed Tomography (CORE320) study ( ClinicalTrials.gov identifier NCT00934037), a clinical trial comparing combined CT angiography (CTA) and perfusion CT with the reference standard catheter angiography plus myocardial perfusion SPECT. SUBJECTS AND METHODS. Prospectively acquired data on 381 CORE320 subjects were analyzed in four groups of testing related to radiation exposure. Radiation dose estimates were compared between modalities for combined CTA and perfusion CT with respect to covariates known to influence radiation exposure and for the main clinical outcomes defined by the trial. The final analysis assessed variations in radiation dose with respect to several factors inherent to the trial. RESULTS. The mean radiation dose estimate for the combined CTA and perfusion CT protocol (8.63 mSv) was significantly (p < 0.0001 for both) less than the average dose delivered from SPECT (10.48 mSv) and the average dose from diagnostic catheter angiography (11.63 mSv). There was no significant difference in estimated CTA-perfusion CT radiation dose for subjects who had false-positive or false-negative results in the CORE320 main analyses in a comparison with subjects for whom the CTA-perfusion CT findings were in accordance with the reference standard SPECT plus catheter angiographic findings. CONCLUSION. Radiation dose estimates from CORE320 support clinical implementation of a combined CT protocol for assessing coronary anatomy and myocardial perfusion.

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

    PubMed

    Majer, Marija; Knežević, Zeljka; Saveta, Miljanić

    2014-09-29

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

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

    SciTech Connect

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

    1993-08-01

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

  16. ESTIMATION OF UV RADIATION DOSE IN NORTHERN MINNESOTA WETLANDS

    EPA Science Inventory

    The ultraviolet (UV) B wavelength range (280 nm to 320 nm) of solar radiation can be a significant biological stressor, and has been hypothesized to be partially responsible for amphibian declines and malformation. This hypothesis has been difficult to evaluate, in part, because ...

  17. ESTIMATION OF UV RADIATION DOSE IN NORTHERN MINNESOTA WETLANDS

    EPA Science Inventory

    The ultraviolet (UV) B wavelength range (280 nm to 320 nm) of solar radiation can be a significant biological stressor, and has been hypothesized to be partially responsible for amphibian declines and malformation. This hypothesis has been difficult to evaluate, in part, because ...

  18. Estimated Ultraviolet Radiation Doses in Wetlands in Six National Parks

    EPA Science Inventory

    Ultraviolet radiation (UVR) has been suggested as a potential cause of population declines and increases in malformations in amphibians. This study indicates that the present distributions of amphibians in four western U.S. National Parks are not related to UVR exposure, and sugg...

  19. Estimated Ultraviolet Radiation Doses in Wetlands in Six National Parks

    EPA Science Inventory

    Ultraviolet radiation (UVR) has been suggested as a potential cause of population declines and increases in malformations in amphibians. This study indicates that the present distributions of amphibians in four western U.S. National Parks are not related to UVR exposure, and sugg...

  20. Radiation dose in cardiac SPECT/CT: An estimation of SSDE and effective dose.

    PubMed

    Abdollahi, Hamid; Shiri, Isaac; Salimi, Yazdan; Sarebani, Maghsoud; Mehdinia, Reza; Deevband, Mohammad Reza; Mahdavi, Seied Rabi; Sohrabi, Ahmad; Bitarafan-Rajabi, Ahmad

    2016-12-01

    The dose levels for Computed Tomography (CT) localization and attenuation correction of Single Photon Emission Computed Tomography (SPECT) are limited and reported as Volume Computed Tomography Dose Index (CTDIvol) and Dose-Length Product (DLP). This work presents CT dose estimation from Cardiac SPECT/CT based on new American Association of Physicists in Medicine (AAPM) Size Specific Dose Estimation (SSDE) parameter, effective dose, organ doses and also emission dose from nuclear issue. Myocardial perfusion SPECT/CT for 509 patients was included in the study. SSDE, effective dose and organ dose were calculated using AAPM guideline and Impact-Dose software. Data were analyzed using R and SPSS statistical software. Spearman-Pearson correlation test and linear regression models were used for finding correlations and relationships among parameters. The mean CTDIvol was 1.34 mGy±0.19 and the mean SSDE was 1.7 mGy±0.16. The mean±SD of effective dose from emission, CT and total dose were 11.5±1.4, 0.49±0.11 and 12.67±1.73 (mSv) respectively. The mean±SD of effective dose from emission, CT and total dose were 11.5±1.4, 0.49±0.11 and 12.67±1.73 (mSv) respectively. The spearman test showed that correlation between body size and organ doses is significant except thyroid and red bone marrow. CTDIvol was strongly dependent on patient size, but SSDE was not. Emission dose was strongly dependent on patient weight, but its dependency was lower to effective diameter. The dose parameters including CTDIvol, DLP, SSDE, effective dose values reported here are very low and below the reference level. This data suggest that appropriate CT acquisition parameters in SPECT/CT localization and attenuation correction are very beneficial for patients and lowering cancer risks. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

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

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

  3. Towards a comprehensive CT image segmentation for thoracic organ radiation dose estimation and reporting

    NASA Astrophysics Data System (ADS)

    Lorenz, Cristian; Ruppertshofen, Heike; Vik, Torbjörn; Prinsen, Peter; Wiegert, Jens

    2014-03-01

    Administered dose of ionizing radiation during medical imaging is an issue of increasing concern for the patient, for the clinical community, and for respective regulatory bodies. CT radiation dose is currently estimated based on a set of very simplifying assumptions which do not take the actual body geometry and organ specific doses into account. This makes it very difficult to accurately report imaging related administered dose and to track it for different organs over the life of the patient. In this paper this deficit is addressed in a two-fold way. In a first step, the absorbed radiation dose in each image voxel is estimated based on a Monte-Carlo simulation of X-ray absorption and scattering. In a second step, the image is segmented into tissue types with different radio sensitivity. In combination this allows to calculate the effective dose as a weighted sum of the individual organ doses. The main purpose of this paper is to assess the feasibility of automatic organ specific dose estimation. With respect to a commercially applicable solution and respective robustness and efficiency requirements, we investigated the effect of dose sampling rather than integration over the organ volume. We focused on the thoracic anatomy as the exemplary body region, imaged frequently by CT. For image segmentation we applied a set of available approaches which allowed us to cover the main thoracic radio-sensitive tissue types. We applied the dose estimation approach to 10 thoracic CT datasets and evaluated segmentation accuracy and administered dose and could show that organ specific dose estimation can be achieved.

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

    SciTech Connect

    Schnitzler, B.G. ); Borowski, S.K. . 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.

  5. MIRD Dose Estimate Report No. 20: Radiation Absorbed-Dose Estimates for 111In- and 90Y-Ibritumomab Tiuxetan

    SciTech Connect

    Fisher, Darrell R.; Shen, Sui; Meredith, Ruby F.

    2009-04-16

    Absorbed dose calculations provide a scientific basis for evaluating the biological effects associated with administered radiopharmaceuticals. In cancer therapy, radiation dosimetry also supports treatment planning, dose-response analyses, predictions of therapy effectiveness, and completeness of patient medical records. In this study, we evaluated the organ radiation absorbed doses resulting from intravenously administered 111In- and 90Y-Ibritumomab Tiuxetan (Zevalin). Methods: Ten patients (six male, four female) with non-Hodgkin’s lymphoma, cared for at three different medical centers, were administered tracer 111In-Ibritumomab Tiuxetan and were assessed using planar scintillation camera imaging at five time points, blood clearance measurements, and CT-organ volumetrics, to determine patient-specific organ biokinetics and dosimetry. Explicit attenuation correction based on transmission scan or transmission measurements provided the fraction of 111In administered activity in seven major organs, the whole body, and remainder tissues over time through complete decay. Activity-time curves were constructed, and radiation doses were calculated using MIRD methods and implementing software (OLINDA-EXM). Results: Mean radiation absorbed doses in 10 cancer patients for 111In- and for 90-Y-Ibritumomab Tiuxetan are reported for 24 organs and the whole body. Biological uptake and retention data are given for seven major source organs, remainder tissues, and the whole body. Median absorbed dose values calculated by this method were compared to previously published dosimetry for Zevalin and the product package insert. Conclusions: Careful dosimetry techniques provide useful information on absorbed dose from administered radiopharmaceuticals in patients. The importance of patient-specific dosimetry emerges in high-dose radioimmunotherapy when the objective of treatment planning is to achieve disease cures safely by limiting radiation doses to any critical normal organ to a

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

    PubMed

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

    2016-05-08

    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.

  7. Expedited Radiation Biodosimetry by Automated Dicentric Chromosome Identification (ADCI) and Dose Estimation.

    PubMed

    Shirley, Ben; Li, Yanxin; Knoll, Joan H M; Rogan, Peter K

    2017-09-04

    Biological radiation dose can be estimated from dicentric chromosome frequencies in metaphase cells. Performing these cytogenetic dicentric chromosome assays is traditionally a manual, labor-intensive process not well suited to handle the volume of samples which may require examination in the wake of a mass casualty event. Automated Dicentric Chromosome Identifier and Dose Estimator (ADCI) software automates this process by examining sets of metaphase images using machine learning-based image processing techniques. The software selects appropriate images for analysis by removing unsuitable images, classifies each object as either a centromere-containing chromosome or non-chromosome, further distinguishes chromosomes as monocentric chromosomes (MCs) or dicentric chromosomes (DCs), determines DC frequency within a sample, and estimates biological radiation dose by comparing sample DC frequency with calibration curves computed using calibration samples. This protocol describes the usage of ADCI software. Typically, both calibration (known dose) and test (unknown dose) sets of metaphase images are imported to perform accurate dose estimation. Optimal images for analysis can be found automatically using preset image filters or can also be filtered through manual inspection. The software processes images within each sample and DC frequencies are computed at different levels of stringency for calling DCs, using a machine learning approach. Linear-quadratic calibration curves are generated based on DC frequencies in calibration samples exposed to known physical doses. Doses of test samples exposed to uncertain radiation levels are estimated from their DC frequencies using these calibration curves. Reports can be generated upon request and provide summary of results of one or more samples, of one or more calibration curves, or of dose estimation.

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

    SciTech Connect

    Blaylock, B.G.

    1993-01-01

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

  9. Estimation of radiation-induced cancer from three-dimensional dose distributions: Concept of organ equivalent dose

    SciTech Connect

    Schneider, Uwe . E-mail: uwe.schneider@psi.ch; Zwahlen, Daniel; Ross, Dieter; Kaser-Hotz, Barbara

    2005-04-01

    Purpose: Estimates of secondary cancer risk after radiotherapy are becoming more important for comparative treatment planning. Modern treatment planning systems provide accurate three-dimensional dose distributions for each individual patient. These data open up new possibilities for more precise estimates of secondary cancer incidence rates in the irradiated organs. We report a new method to estimate organ-specific radiation-induced cancer incidence rates. The concept of an organ equivalent dose (OED) for radiation-induced cancer assumes that any two dose distributions in an organ are equivalent if they cause the same radiation-induced cancer incidence. Methods and Materials: The two operational parameters of the OED concept are the organ-specific cancer incidence rate at low doses, which is taken from the data of the atomic bomb survivors, and cell sterilization at higher doses. The effect of cell sterilization in various organs was estimated by analyzing the secondary cancer incidence data of patients with Hodgkin's disease who were treated with radiotherapy in between 1962 and 1993. The radiotherapy plans used at the time the patients had been treated were reconstructed on a fully segmented whole body CT scan. The dose distributions were calculated in individual organs for which cancer incidence data were available. The model parameter that described cell sterilization was obtained by analyzing the dose and cancer incidence rates for the individual organs. Results: We found organ-specific cell radiosensitivities that varied from 0.017 for the mouth and pharynx up to 1.592 for the bladder. Using the two model parameters (organ-specific cancer incidence rate and the parameter characterizing cell sterilization), the OED concept can be applied to any three-dimensional dose distribution to analyze cancer incidence. Conclusion: We believe that the concept of OED presented in this investigation represents a first step in assessing the potential risk of secondary

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

    SciTech Connect

    Sparks, R.B.; Stabin, M.G.

    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.

  11. Estimates of radiation doses in space on the basis of current data.

    PubMed

    Foelsche, T

    1963-01-01

    A gross survey of data on Van Allen belt radiations, galactic cosmic radiation, and solar cosmic radiation is presented. On the basis of these data that are, in part, fragmentary and uncertain, upper and lower limits of rad doses under different amounts of mass shielding are estimated. The estimates are preliminary especially in the cases of chance encounter with solar flare protons. Generally, the relative biological effectiveness of the high energetic space radiations and their secondaries appear insufficiently known to give detailed biological or rem doses. The overall ionization dosage of the low level galactic cosmic radiation in free space is estimated to be even in solar minimum years equivalent to less than 50 rem/year or 1 rem/week. Mass shielding up to 80 g/cm2 would not reduce the ionization dosage but would shield against heavy primaries and heavy ionizing secondaries, thus reducing the biological dose. The flux of energetic protons in the maximum intensity zone of the inner Van Allen belt is by about four orders of magnitude higher, their energy and penetration power, of course, lower. A shield of 25 g/cm2 would reduce the dose rate from 20 rad/hour under 2 g/cm2 to 5 rad/hour. These proton dose rates and also the electron and X-radiation dose rates under some g/cm2 shielding of low z-number material will not constitute a radiation hazard for flights straight through the inner and outer belt in about two hours. Staying within the maximum of the inner belt for two days would, however, lead even within 25 g/cm2 depth of outer shield and body itself to a dose of 200 rad which is on the permissible limit. Extreme solar cosmic ray events or proton showers of high intensity and a duration of days occurred with a frequency of 1-4 per year during the last highly active cycle. For the penetrating, most intense high energy event of February 23, 1956, the dose within 25 g/cm2 is estimated to have been in the order of 50 rad. In most cases the dose decreased more

  12. A method for estimating occupational radiation dose to individuals, using weekly dosimetry data

    SciTech Connect

    Mitchell, T.J.; Ostrouchov, G.; Frome, E.L.; Kerr, G.D.

    1993-12-01

    Statistical analyses of data from epidemiologic studies of workers exposed to radiation have been based on recorded annual radiation doses. It is usually assumed that the annual dose values are known exactly, although it is generally recognized that the data contain uncertainty due to measurement error and bias. We propose the use of a probability distribution to describe an individual`s dose during a specific period of time. Statistical methods for estimating this dose distribution are developed. The methods take into account the ``measurement error`` that is produced by the dosimetry system, and the bias that was introduced by policies that lead to right censoring of small doses as zero. The method is applied to a sample of dose histories obtained from hard copy dosimetry records at Oak Ridge National Laboratory (ORNL). The result of this evaluation raises serious questions about the validity of the historical personnel dosimetry data that is currently being used in low-dose studies of nuclear industry workers. In particular, it appears that there was a systematic underestimation of doses for ORNL workers. This could result in biased estimates of dose-response coefficients and their standard errors.

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

    SciTech Connect

    Hoel, D. G.

    1998-11-01

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

  14. An estimation of radiation doses to benthic invertebrates from sediments collected near a Canadian uranium mine.

    PubMed

    Thomas, P; Liber, K

    2001-10-01

    A new method is described for calculating radiation doses to benthic invertebrates from radionuclide concentrations in freshwater sediment. Both internal and external radiation doses were estimated for all 14 principal radionuclides of the uranium-238 decay series. Sediments were collected from three sites downstream of a uranium mining operation in northern Saskatchewan, Canada. Sediments from two sites, located approximately 1.6 and 4.4 km downstream from mining operations, yielded absorbed doses to both larval midges, Chironomus tentans, and adult amphipods, Hyalella azteca, of 59-60 and 19 mGy/year, respectively, compared to 3.2 mGy/year for a nearby control site. External beta radiation from protactinium-234 (234Pa) and alpha radiation from uranium (U) contributed most of the dose at the impacted sites, whereas polonium-210 (210Po) was most important at the control site. If a weighting factor of 20 was employed for the greater biological effect of alpha vs. beta and gamma radiation, then total equivalent doses rose to 540-560 mGy/year at the site closest to uranium operations. Such equivalent doses are above the 360-mGy/year no-observed-effect level for reproductive effects in vertebrates from gamma radiation exposure. Data are not available to determine the effect of such doses on benthic organisms, but they are high enough to warrant concern. Detrimental effects have been observed in H. azteca at similar uranium concentration in laboratory toxicity tests, but it remains unclear whether the radiotoxicity or the chemotoxicity of uranium is responsible for these effects.

  15. Estimated radiation dose to the newborn in FDG-PET studies

    SciTech Connect

    Ruotsalainen, U.; Suhonen-Polvi, H.; Eronen, E.; Kinnala, A.

    1996-02-01

    The aim of this study was to estimate the radiation dose due to intravenous injection of 2-[{sup 18}F]fluoro-2-deoxy-D-glucose (FDG) for infants studied with PET. The radioactivity concentration in the brain and bladder content was measured with PET to determine the cumulated activity in these organs in 21 infant FDG studies. The individual organ masses were estimated according to the whole-body and brain masses, and they were used to calculate the absorbed dose per unit cumulated activity (S values). For organs other than brain and bladder, the cumulated activity was defined from adult studies. For each individual patient, the absorbed dose to the brain, bladder wall and selected organs were calculated. An estimation of the effective dose was determined. Whole-body distribution of FDG in the infants differed from adults: a greater proportion of the injected activity accumulated into the brain (9% versus 7%) and less was excreted to urine (7% versus 20% respectively). The measured cumulated activity in the brain was 0.25 MBq {center_dot} h/MBq and in the bladder content 0.04 MBq {center_dot}h/MBq with a large individual variation in latter. The calculated absorbed dose was 0.24 mGy/MBq to the brain and 1.03 mGy/MBq to the bladder wall. The estimated effective dose was 0.43 mSv/MBq. The dose to the bladder wall was lower in infants as compared to adults with ordinary amounts of injected activity. The greater amount of activity remaining in the body may increase the dose to other organs. The effective dose was lower compared to adults and conventional nuclear medicine studies of infants. PET can be a valuable tool in pediatric nuclear medicine because of good resolution images, sensitive radiation measurement and a variety of tracers labeled with short-lived isotopes. 27 refs., 4 figs., 2 tabs.

  16. Aircrew radiation dose estimates during recent solar particle events and the effect of particle anisotropy.

    PubMed

    Al Anid, H; Lewis, B J; Bennett, L G I; Takada, M; Duldig, M

    2014-01-01

    A model was developed using a Monte-Carlo radiation transport code, MCNPX, to estimate the additional radiation exposure to aircrew members during solar particle events. The model transports an extrapolated particle spectrum based on satellite measurements through the atmosphere to aircraft altitudes. This code produces the estimated flux at a specific altitude where radiation dose conversion coefficients are applied to convert the particle flux into effective and ambient dose-equivalent rates. A cut-off rigidity model accounts for the shielding effects of the Earth's magnetic field. Comparisons were made between the model predictions and actual flight measurements taken with various types of instruments used to measure the mixed radiation field during ground level enhancements (GLEs) 60 and 65. An anisotropy analysis that uses neutron monitor responses and the pitch angle distribution of energetic solar particles was used to identify particle anisotropy for a solar event in December 2006. In anticipation of future commercial use, a computer code has been developed to implement the radiation dose assessment model for routine analysis.

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

    SciTech Connect

    Jones, Bleddyn . E-mail: b.jones.1@bham.ac.uk; Sanghera, Paul

    2007-06-01

    Purpose: To determine the radiobiologic parameters for high-grade gliomas. Methods and Materials: The biologic effective dose concept is used to estimate the {alpha}/{beta} 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 {alpha}/{beta} and K estimate is 9.32 Gy and 0.23 Gy/d, respectively. Using the published surviving fraction after 2-Gy exposure (SF{sub 2}) data, and the above {alpha}/{beta} ratio, the estimated median {alpha} value was 0.077 Gy{sup -1}, {beta} was 0.009 Gy{sup -2}, and the cellular doubling time was 39.5 days. The median equivalent biologic effective dose of temozolomide was 11.03 Gy{sub 9.3} (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.

  18. Quantitative estimation of UV light dose concomitant to irradiation with ionizing radiation

    NASA Astrophysics Data System (ADS)

    Petin, Vladislav G.; Morozov, Ivan I.; Kim, Jin Kyu; Semkina, Maria A.

    2011-01-01

    A simple mathematical model for biological estimation of UV light dose concomitant to ionizing radiation was suggested. This approach was applied to determine the dependency of equivalent UV light dose accompanied by 100 Gy of ionizing radiation on energy of sparsely ionizing radiation and on volume of the exposed cell suspension. It was revealed that the relative excitation contribution to the total lethal effect and the value of UV dose was greatly increased with an increase in energy of ionizing radiation and volume of irradiated suspensions. It is concluded that these observations are in agreement with the supposition that Čerenkov emission is responsible for the production of UV light damage and the phenomenon of photoreactivation observed after ionizing exposure of bacterial and yeast cells hypersensitive to UV light. A possible synergistic interaction of the damages produced by ionizations and excitations as well as a probable participation of UV component of ionizing radiation in the mechanism of hormesis and adaptive response observed after ionizing radiation exposure is discussed.

  19. Estimation of the committed radiation dose resulting from gamma radionuclides ingested with food.

    PubMed

    Godyń, Piotr; Dołhańczuk-Śródka, Agnieszka; Ziembik, Zbigniew; Moliszewska, Ewa

    The objective of the study was to estimate the value of the radiation dose absorbed in consequence of consumption of popular food products for individual age groups. Potatoes, corn and sugar beet were selected for the study. Edible parts of these plants were collected in experimental fields of the KWS Lochów Polska Sp. z o.o. seeding company in Kondratowice (Poland). On the basis of the obtained study results, it can be stated that in consequence of consumption of the selected food products, people may receive increased doses from both natural and artificial radioactive isotopes. The doses calculated for several age groups do not show any health hazards in consequence of consumption of the tested food. One of the determined radionuclides was (137)Cs; however, its presence in the absorbed dose is lower than the doses from natural radioactive isotopes, in particular (40)K.

  20. Radiation dose estimates for C-11 iomazenil, a benzodiazepine receptor radioligand

    SciTech Connect

    Sparks, R.B.; Dey, H.M.; Siebyl, I.B.

    1994-05-01

    SPECT imaging of the brain with I-123 iomazenil has shown avid uptake of the radioligand in a distribution consistent with benzodiazepine receptor binding. It was desirable to radiolabel this compound with a positron emitting radionuclide so that quantitation of the receptor density could be assessed with PET imaging. Radiation dose estimates for C-11 iomazenil were calculated prior to obtaining Institutional Review Board approval of this procedure. A previously published multicompartmental model was used as the biological model for estimating residence times associated with the C-11 labeled iomazenil. According to this model, 85-90% is excreted in the urine and 10-15% in the feces. A dynamic, voiding urinary bladder model was utilized for activity excreted renally and the ICRP 30 gastrointestinal tract kinetic model was used for activity excreted via the hepatobiliary system. Absorbed doses from C-11 (I-123) iomazenil to the urinary bladder were calculated to be 0.099 mGy/MBq (0.19 mGy/MBq) for a 4.8 hour bladder voiding interval. Shortening the bladder voiding interval to 2.0 hours had little effect on the bladder wall dose (0.095 mGy/MBq). However, a 30-minute void interval was estimated to lower the bladder wall dose substantially (0.045 mGy/MBq). Absorbed dose to the kidney was higher for C-11 iomazenil (0.054 vs 0.031 mGy/MBq) than for I-123 iomazenil due to rapid, early renal excretion of this very short-lived positron emitter. Doses to the gastrointestinal tract were estimated to be 4- to 20-fold lower for C-11 iomazenil compared to I-123 iomazenil. Overall, labeling iomazenil with C-11 rather than I-123 greatly reduces the radiation dose, per unit administered, to all organs except the kidneys.

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

    SciTech Connect

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

    2011-01-15

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

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

    PubMed Central

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

    2011-01-01

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

  3. Estimation of radiation exposure of different dose saving techniques in 128-slice computed tomography coronary angiography.

    PubMed

    Ketelsen, Dominik; Fenchel, Michael; Buchgeister, Markus; Thomas, Christoph; Boehringer, Nadine; Tsiflikas, Ilias; Kaempf, Michael; Syha, Roland; Claussen, Claus D; Heuschmid, Martin

    2012-02-01

    To estimate the effective dose of cardiac CT with different dose saving strategies dependent on varying heart rates. For dose measurements, an Alderson-Rando-phantom equipped with thermoluminescent dosimeters was used. The effective dose was calculated according to ICRP 103. Exposure was performed on a 128-slice single source scanner providing a rotation time of 0.30s and standard protocols with 120 kV and 160 mAs/rot. Protocols were evaluated without ECG-pulsing, with two different ECG-pulsing techniques, and automated exposure control with a simulated heart rate of 60 and 100 beats per minute. Depending on different dose saving techniques and heart rate, the effective whole-body dose of a cardiac scan ranged from 2.8 to 9.5 mSv and from 4.3 to 16.0 mSv for males and females, respectively. The radiation-sensitive breast tissue in the primary scan range results in an increased female dose of 66.7 ± 6.0%. Prospective triggering has the greatest potential to reduce the effective dose to 27.8%, compared to a comparable scan protocol with retrospective ECG-triggering with no ECG-pulsing. Furthermore, the heart rate influences the radiation exposure by increasing significantly at lower heart rates. Due to this broad variability in radiation exposure of a cardiac CT, the radiologist and the CT technician should be aware of the different dose reduction strategies. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

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

    PubMed

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

    2016-01-01

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

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

    PubMed Central

    2016-01-01

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

  6. Radiation dose from MDCT using Monte Carlo simulations: estimating fetal dose due to pulmonary embolism scans accounting for overscan

    NASA Astrophysics Data System (ADS)

    Angel, E.; Wellnitz, C.; Goodsitt, M.; DeMarco, J.; Cagnon, C.; Ghatali, M.; Cody, D.; Stevens, D.; McCollough, C.; Primak, A.; McNitt-Gray, M.

    2007-03-01

    Pregnant women with shortness of breath are increasingly referred for CT Angiography to rule out Pulmonary Embolism (PE). While this exam is typically focused on the lungs, extending scan boundaries and overscan can add to the irradiated volume and have implications on fetal dose. The purpose of this work was to estimate radiation dose to the fetus when various levels of overscan were encountered. Two voxelized models of pregnant patients derived from actual patient anatomy were created based on image data. The models represent an early (< 7 weeks) and late term pregnancy (36 weeks). A previously validated Monte Carlo model of an MDCT scanner was used that takes into account physical details of the scanner. Simulated helical scans used 120 kVp, 4x5 mm beam collimation, pitch 1, and varying beam-off locations (edge of the irradiated volume) were used to represent different protocols plus overscan. Normalized dose (mGy/100mAs) was calculated for each fetus. For the early term and the late term pregnancy models, fetal dose estimates for a standard thoracic PE exam were estimated to be 0.05 and 0.3 mGy/100mAs, respectively, increasing to 9 mGy/100mAs when the beam-off location was extended to encompass the fetus. When performing PE exams to rule out PE in pregnant patients, the beam-off location may have a large effect on fetal dose, especially for late term pregnancies. Careful consideration of ending location of the x-ray beam - and not the end of image data - could result in significant reduction in radiation dose to the fetus.

  7. Correlation of clinical outcome to the estimated radiation dose from Boron Neutron Capture Therapy (BNCT)

    SciTech Connect

    Chadha, M.; Coderre, J.A.; Chanana, A.D.

    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.

  8. Radiation exposure and dose estimates for a nuclear-powered manned Mars sprint mission

    NASA Technical Reports Server (NTRS)

    Nealy, John E.; Simonsen, Lisa C.; Wilson, John W.; Townsend, Lawrence W.; Schnitzler, Bruce G.; Qualls, Garry D.; Gates, Michele M.

    1991-01-01

    A conceptual manned mission to Mars is analyzed in order to estimate potential ionizing radiation doses that may be incurred by crew members during the course of the mission. The scenario is set for a journey during the solar active period and includes a brief stay on the Martian surface. Propulsion is assumed to be provided by nuclear thermal rocket power, and estimates of the dose contributions from the reactors are included. However, due to effective shielding of the reactors by large propellant tanks, it is found that the incurred doses are principally due to the charged particle natural environment. Recent data (August-December 1989) for large solar proton events are used to simulate the flame environment, while standard models are used for the trapped particle and galactic cosmic ray contributions. Shield effectiveness for several candidate materials are investigated.

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

    NASA Astrophysics Data System (ADS)

    McMillan, Kyle Lorin

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

  10. Cardiac-Specific Conversion Factors to Estimate Radiation Effective Dose From Dose-Length Product in Computed Tomography.

    PubMed

    Trattner, Sigal; Halliburton, Sandra; Thompson, Carla M; Xu, Yanping; Chelliah, Anjali; Jambawalikar, Sachin R; Peng, Boyu; Peters, M Robert; Jacobs, Jill E; Ghesani, Munir; Jang, James J; Al-Khalidi, Hussein; Einstein, Andrew J

    2017-08-16

    This study sought to determine updated conversion factors (k-factors) that would enable accurate estimation of radiation effective dose (ED) for coronary computed tomography angiography (CTA) and calcium scoring performed on 12 contemporary scanner models and current clinical cardiac protocols and to compare these methods to the standard chest k-factor of 0.014 mSv·mGy(-1)cm(-1). Accurate estimation of ED from cardiac CT scans is essential to meaningfully compare the benefits and risks of different cardiac imaging strategies and optimize test and protocol selection. Presently, ED from cardiac CT is generally estimated by multiplying a scanner-reported parameter, the dose-length product, by a k-factor which was determined for noncardiac chest CT, using single-slice scanners and a superseded definition of ED. Metal-oxide-semiconductor field-effect transistor radiation detectors were positioned in organs of anthropomorphic phantoms, which were scanned using all cardiac protocols, 120 clinical protocols in total, on 12 CT scanners representing the spectrum of scanners from 5 manufacturers (GE, Hitachi, Philips, Siemens, Toshiba). Organ doses were determined for each protocol, and ED was calculated as defined in International Commission on Radiological Protection Publication 103. Effective doses and scanner-reported dose-length products were used to determine k-factors for each scanner model and protocol. k-Factors averaged 0.026 mSv·mGy(-1)cm(-1) (95% confidence interval: 0.0258 to 0.0266) and ranged between 0.020 and 0.035 mSv·mGy(-1)cm(-1). The standard chest k-factor underestimates ED by an average of 46%, ranging from 30% to 60%, depending on scanner, mode, and tube potential. Factors were higher for prospective axial versus retrospective helical scan modes, calcium scoring versus coronary CTA, and higher (100 to 120 kV) versus lower (80 kV) tube potential and varied among scanner models (range of average k-factors: 0.0229 to 0.0277 mSv·mGy(-1)cm(-1)). Cardiac

  11. Estimation of radiation doses for atomic-bomb survivors in the Hiroshima University Registry

    SciTech Connect

    Hoshi, M.; Matsuura, M.; Hayakawa, N.; Kamada, N.; Ito, C.

    1996-05-01

    The present study presents the Hiroshima University Registry of atomic bomb survivors, of which the total number is about 270,000, and application of absorbed doses. From this registry, we picked up 49,102 survivors and applied organ doses based on the dosimetry system 1986 (DS86), which is named the Atomic Bomb Survivor 1993 Dose (ABS93D). The applied dose data are based on the tables listed in the DS86 final report such as the free-in-air kermas, the house shielding factors, and organ dose factors for the active bone marrow and the breast. Calculations for the 13 other organs provided in DS86 are possible. To obtained the organ doses for each survivor, it is necessary to obtain information concerning (1) place exposed, (2) whether they were shielded or not, and (3) age. ABS93D body transmission factors for active bone marrow for neutrons and gamma rays agreed with DS 86 to within a few percent. Of the survivors studied, 35, 123 of them were used for the relative risk estimation of leukemia mortality, adopting the same method as the Radiation Effects Research Foundation (RERF) for comparison. For the observation period from 1968 to 1989, the analyzed relative risks for leukemia mortality at 1 Gy by shielded kerm and by active bone marrow dose are 2.01 and 2.37, respectively, which are consistent with the RERF results. 11 refs., 1 fig., 3 tabs.

  12. Estimation of internal organ motion-induced variance in radiation dose in non-gated radiotherapy

    NASA Astrophysics Data System (ADS)

    Zhou, Sumin; Zhu, Xiaofeng; Zhang, Mutian; Zheng, Dandan; Lei, Yu; Li, Sicong; Bennion, Nathan; Verma, Vivek; Zhen, Weining; Enke, Charles

    2016-12-01

    In the delivery of non-gated radiotherapy (RT), owing to intra-fraction organ motion, a certain degree of RT dose uncertainty is present. Herein, we propose a novel mathematical algorithm to estimate the mean and variance of RT dose that is delivered without gating. These parameters are specific to individual internal organ motion, dependent on individual treatment plans, and relevant to the RT delivery process. This algorithm uses images from a patient’s 4D simulation study to model the actual patient internal organ motion during RT delivery. All necessary dose rate calculations are performed in fixed patient internal organ motion states. The analytical and deterministic formulae of mean and variance in dose from non-gated RT were derived directly via statistical averaging of the calculated dose rate over possible random internal organ motion initial phases, and did not require constructing relevant histograms. All results are expressed in dose rate Fourier transform coefficients for computational efficiency. Exact solutions are provided to simplified, yet still clinically relevant, cases. Results from a volumetric-modulated arc therapy (VMAT) patient case are also presented. The results obtained from our mathematical algorithm can aid clinical decisions by providing information regarding both mean and variance of radiation dose to non-gated patients prior to RT delivery.

  13. Development of In Vivo Tooth EPR for Individual Radiation Dose Estimation and Screening

    PubMed Central

    Williams, Benjamin B.; Dong, Ruhong; Kmiec, Maciej; Burke, Greg; Demidenko, Eugene; Gladstone, David; Nicolalde, Roberto J; Sucheta, Artur; Lesniewski, Piotr; Swartz, Harold M

    2009-01-01

    The development of in vivo EPR has made it feasible to perform tooth dosimetry measurements in situ, greatly expanding the potential for using this approach for immediate screening after radiation exposures. The ability of in vivo tooth dosimetry to provide estimates of absorbed dose has been established through a series of experiments using unirradiated volunteers with specifically irradiated molar teeth placed in situ within gaps in their dentition and in natural canine teeth of patients who have completed courses of radiation therapy for head and neck cancers. Multiple measurements in patients who have received radiation therapy demonstrate the expected heterogeneous dose distributions. Dose response curves have been generated using both populations and, using the current methodology and instrument, the standard error of prediction based on single 4.5 minute measurements is approximately 1.5 Gy for inserted molar teeth and between 2.0 and 2.5 Gy in the more irregularly shaped canine teeth. Averaging of independent measurements can reduce this error significantly to values near 1 Gy. Developments to reduce these errors are underway, focusing on geometric optimization of the resonators, detector positioning techniques, and optimal data averaging approaches. In summary, it seems plausible that the EPR dosimetry techniques will have an important role in retrospective dosimetry for exposures involving large numbers of individuals. PMID:20065702

  14. Development of in vivo tooth EPR for individual radiation dose estimation and screening.

    PubMed

    Williams, Benjamin B; Dong, Ruhong; Kmiec, Maciej; Burke, Greg; Demidenko, Eugene; Gladstone, David; Nicolalde, Roberto J; Sucheta, Artur; Lesniewski, Piotr; Swartz, Harold M

    2010-02-01

    The development of in vivo EPR has made it feasible to perform tooth dosimetry measurements in situ, greatly expanding the potential for using this approach for immediate screening after radiation exposures. The ability of in vivo tooth dosimetry to provide estimates of absorbed dose has been established through a series of experiments using unirradiated volunteers with specifically irradiated molar teeth placed in situ within gaps in their dentition and in natural canine teeth of patients who have completed courses of radiation therapy for head and neck cancers. Multiple measurements in patients who have received radiation therapy demonstrate the expected heterogeneous dose distributions. Dose-response curves have been generated using both populations and, using the current methodology and instrument, the standard error of prediction based on single 4.5-min measurements is approximately 1.5 Gy for inserted molar teeth and between 2.0 and 2.5 Gy in the more irregularly shaped canine teeth. Averaging of independent measurements can reduce this error significantly to values near 1 Gy. Developments to reduce these errors are underway, focusing on geometric optimization of the resonators, detector positioning techniques, and optimal data averaging approaches. In summary, it seems plausible that the EPR dosimetry techniques will have an important role in retrospective dosimetry for exposures involving large numbers of individuals.

  15. Monte Carlo estimation of radiation doses during paediatric barium meal and cystourethrography examinations

    NASA Astrophysics Data System (ADS)

    Dimitriadis, A.; Gialousis, G.; Makri, T.; Karlatira, M.; Karaiskos, P.; Georgiou, E.; Papaodysseas, S.; Yakoumakis, E.

    2011-01-01

    Organ doses are important quantities in assessing the radiation risk. In the case of children, estimation of this risk is of particular concern due to their significant radiosensitivity and the greater health detriment. The purpose of this study is to estimate the organ doses to paediatric patients undergoing barium meal and micturating cystourethrography examinations by clinical measurements and Monte Carlo simulation. In clinical measurements, dose-area products (DAPs) were assessed during examination of 50 patients undergoing barium meal and 90 patients undergoing cystourethrography examinations, separated equally within three age categories: namely newborn, 1 year and 5 years old. Monte Carlo simulation of photon transport in male and female mathematical phantoms was applied using the MCNP5 code in order to estimate the equivalent organ doses. Regarding the micturating cystourethrography examinations, the organs receiving considerable amounts of radiation doses were the urinary bladder (1.87, 2.43 and 4.7 mSv, the first, second and third value in the parentheses corresponds to neonatal, 1 year old and 5 year old patients, respectively), the large intestines (1.54, 1.8, 3.1 mSv), the small intestines (1.34, 1.56, 2.78 mSv), the stomach (1.46, 1.02, 2.01 mSv) and the gall bladder (1.46, 1.66, 2.18 mSv), depending upon the age of the child. Organs receiving considerable amounts of radiation during barium meal examinations were the stomach (9.81, 9.92, 11.5 mSv), the gall bladder (3.05, 5.74, 7.15 mSv), the rib bones (9.82, 10.1, 11.1 mSv) and the pancreas (5.8, 5.93, 6.65 mSv), depending upon the age of the child. DAPs to organ/effective doses conversion factors were derived for each age and examination in order to be compared with other studies.

  16. Monte Carlo estimation of radiation doses during paediatric barium meal and cystourethrography examinations.

    PubMed

    Dimitriadis, A; Gialousis, G; Makri, T; Karlatira, M; Karaiskos, P; Georgiou, E; Papaodysseas, S; Yakoumakis, E

    2011-01-21

    Organ doses are important quantities in assessing the radiation risk. In the case of children, estimation of this risk is of particular concern due to their significant radiosensitivity and the greater health detriment. The purpose of this study is to estimate the organ doses to paediatric patients undergoing barium meal and micturating cystourethrography examinations by clinical measurements and Monte Carlo simulation. In clinical measurements, dose-area products (DAPs) were assessed during examination of 50 patients undergoing barium meal and 90 patients undergoing cystourethrography examinations, separated equally within three age categories: namely newborn, 1 year and 5 years old. Monte Carlo simulation of photon transport in male and female mathematical phantoms was applied using the MCNP5 code in order to estimate the equivalent organ doses. Regarding the micturating cystourethrography examinations, the organs receiving considerable amounts of radiation doses were the urinary bladder (1.87, 2.43 and 4.7 mSv, the first, second and third value in the parentheses corresponds to neonatal, 1 year old and 5 year old patients, respectively), the large intestines (1.54, 1.8, 3.1 mSv), the small intestines (1.34, 1.56, 2.78 mSv), the stomach (1.46, 1.02, 2.01 mSv) and the gall bladder (1.46, 1.66, 2.18 mSv), depending upon the age of the child. Organs receiving considerable amounts of radiation during barium meal examinations were the stomach (9.81, 9.92, 11.5 mSv), the gall bladder (3.05, 5.74, 7.15 mSv), the rib bones (9.82, 10.1, 11.1 mSv) and the pancreas (5.8, 5.93, 6.65 mSv), depending upon the age of the child. DAPs to organ/effective doses conversion factors were derived for each age and examination in order to be compared with other studies.

  17. Modeling estimates of the effect of acid rain on background radiation dose.

    PubMed Central

    Sheppard, S C; Sheppard, M I

    1988-01-01

    Acid rain causes accelerated mobilization of many materials in soils. Natural and anthropogenic radionuclides, especially 226Ra and 137Cs, are among these materials. Okamoto is apparently the only researcher to date who has attempted to quantify the effect of acid rain on the "background" radiation dose to man. He estimated an increase in dose by a factor of 1.3 following a decrease in soil pH of 1 unit. We reviewed literature that described the effects of changes in pH on mobility and plant uptake of Ra and Cs. Generally, a decrease in soil pH by 1 unit will increase mobility and plant uptake by factors of 2 to 7. Thus, Okamoto's dose estimate may be too low. We applied several simulation models to confirm Okamoto's ideas, with most emphasis on an atmospherically driven soil model that predicts water and nuclide flow through a soil profile. We modeled a typical, acid-rain sensitive soil using meteorological data from Geraldton, Ontario. The results, within the range of effects on the soil expected from acidification, showed essentially direct proportionality between the mobility of the nuclides and dose. This supports some of the assumptions invoked by Okamoto. We conclude that a decrease in pH of 1 unit may increase the mobility of Ra and Cs by a factor of 2 or more. Our models predict that this will lead to similar increases in plant uptake and radiological dose to man. Although health effects following such a small increase in dose have not been statistically demonstrated, any increase in dose is probably undesirable. PMID:3203639

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

    PubMed Central

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

    2008-01-01

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

  19. Dose estimation outside radiation field using Pinpoint and Semiflex ionization chamber detectors

    NASA Astrophysics Data System (ADS)

    Abdelaal, Ahmed M.; Attalla, Ehab M.; Elshemey, Wael M.

    2017-10-01

    This work aims to provide a comparison between two important detectors (Pinpoint and Semiflex) that are frequently used in radiation dosimetery in radiotherapy. This is carried out through the employment of both detectors in a quantitative estimation of the change in out-of-field dose with important dosimetric parameters such as field size (from 5×5 cm2 to 30×30 cm2) and depth (from 1.5 cm to 30 cm) at two different energies (6 MV and 15 MV) and two different collimator angles (0-90°). The change in out-of-field dose with Source-Skin-Distance (SSD) from 80 to 115 cm is also studied using both detectors. Results show that, the Pinpoint and Semiflex detectors both reported an increase in out-of-field dose with field size, depth, energy and SSD. In almost all measurements, Pinpoint detector reported considerably higher out-of-field dose values compared to Semiflex. For 6 MV and 0° collimator angle, the out-of-field dose at field size of 30×30 cm2 and at a depth of 1.5 cm is 7.3% for Pinpoint detector compared to 4.3% for Semiflex. At collimator angle of 90°, the out-of-field dose is 6.5% for Pinpoint detector compared to 5.5% for semiflex. The out-of-field dose for a depth of 30 cm and field size of 10×10 cm is 7.9% for Pinpoint detector compared to 5.9% for Semiflex. For 15 MV and 0° collimator angle, the out-of-field dose at field size of 30×30 cm2 and at a depth of 1.5 cm is 7.5% for Pinpoint detector compared 5.1% for Semiflex. At 6 MV, field size of 10×10 cm2 and depth of 1.5 cm, the out-of-field dose at SSD 115 cm is 3.7% for Pinpoint detector compared to 3.4% for Semiflex. The considerably higher out-of-field dose values reported by Pinpoint detector compared to Semiflex may be attributed to the relatively higher sensitivity of Pinpoint detector for low doses (such as out-of-field doses). Therefore, for reliable out-of-field dose measurements a Pinpoint detector is highly recommended.

  20. Estimation of the absorbed dose in radiation-processed food. 4. EPR measurements on eggshell

    SciTech Connect

    Desrosiers, M.F.; Le, F.G. ); Harewood, P.M.; Josephson, E.S. ); Montesalvo, M. )

    1993-09-01

    Fresh whole eggs treated with ionizing radiation for Salmonellae control testing. The eggshell was then removed and examined by electron paramagnetic resonance (EPR) spectroscopy to determine if EPR could be used to (1) distinguish irradiated from unirradiated eggs and (2) assess the absorbed dose. No EPR signals were detected in unirradiated eggs, while strong signals were measurable for more than 200 days after irradiation. Although a number of EPR signals were measured, the most intense resonance (g = 2.0019) was used for dosimetry throughout the study. This signal was observed to increase linearly with dose (up to [approximately]6 kGy), which decayed [approximately]20% within the first 5 days after irradiation and remained relatively constant thereafter. The standard added-dose method was used to assess, retrospectively, the dose to eggs processed at 0.2, 0.7, and 1.4 kGy. Relatively good results were obtained when measurement was made on the day the shell was reirradiated; with this procedure estimates were better for shell processed at the lower doses.

  1. [18F]Galacto-RGD: synthesis, radiolabeling, metabolic stability, and radiation dose estimates.

    PubMed

    Haubner, Roland; Kuhnast, Bertrand; Mang, Christian; Weber, Wolfgang A; Kessler, Horst; Wester, Hans-Jürgen; Schwaiger, Markus

    2004-01-01

    It has been demonstrated in various murine tumor models that radiolabeled RGD-peptides can be used for noninvasive determination of alphavbeta3 integrin expression. Introduction of sugar moieties improved the pharmacokinetic properties of these peptides and led to tracer with good tumor-to-background ratios. Here we describe the synthesis, radiolabeling, and the metabolic stability of a glycosylated RGD-peptide ([18F]Galacto-RGD) and give first radiation dose estimates for this tracer. The peptide was assembled on a solid support using Fmoc-protocols and cyclized under high dilution conditions. It was conjugated with a sugar amino acid, which can be synthesized via a four-step synthesis starting from pentaacetyl-protected galactose. For radiolabeling of the glycopeptide, 4-nitrophenyl-2-[18F]fluoropropionate was used. This prosthetic group allowed synthesis of [18F]Galacto-RGD with a maximum decay-corrected radiochemical yield of up to 85% and radiochemical purity >98%. The overall radiochemical yield was 29 +/- 5% with a total reaction time including final HPLC preparation of 200 +/- 18 min. The metabolic stability of [18F]Galacto-RGD was determined in mouse blood and liver, kidney, and tumor homogenates 2 h after tracer injection. The average fraction of intact tracer in these organs was approximately 87%, 76%, 69%, and 87%, respectively, indicating high in vivo stability of the radiolabeled glycopeptide. The expected radiation dose to humans after injection of [18F]Galacto-RGD has been estimated on the basis of dynamic PET studies with New Zealand white rabbits. According to the residence times in these animals the effective dose was calculated using the MIRDOSE 3.0 program as 2.2 x 10(-2) mGy/MBq. In conclusion, [18F]Galacto-RGD can be synthesized in high radiochemical yields and radiochemical purity. Despite the time-consuming synthesis of the prosthetic group 185 MBq of [18F]Galacto-RGD, a sufficient dose for patient studies, can be produced starting with

  2. Thyroid Dose Estimates for a Cohort of Belarusian Children Exposed to Radiation from the Chernobyl Accident

    PubMed Central

    Drozdovitch, Vladimir; Minenko, Victor; Khrouch, Valeri; Leshcheva, Svetlana; Gavrilin, Yury; Khrutchinsky, Arkady; Kukhta, Tatiana; Kutsen, Semion; Luckyanov, Nickolas; Shinkarev, Sergey; Tretyakevich, Sergey; Trofimik, Sergey; Voillequé, Paul; Bouville, André

    2013-01-01

    The U.S. National Cancer Institute, in collaboration with the Belarusian Ministry of Health, is conducting a study of thyroid cancer and other thyroid diseases in a cohort of about 12,000 persons who were exposed to fallout from the Chernobyl accident in April 1986. The study subjects were 18 years old or younger at the time of exposure and resided in Belarus in the most contaminated areas of the Gomel and Mogilev Oblasts, as well as in the city of Minsk. All cohort members had at least one direct thyroid measurement made in April–June 1986. Individual data on residential history, consumption of milk, milk products and leafy vegetables as well as administration of stable iodine were collected for all cohort members by means of personal interviews conducted between 1996 and 2007. Based on the estimated 131I activities in the thyroids, which were derived from the direct thyroid measurements, and on the responses to the questionnaires, individual thyroid doses from intakes of 131I were reconstructed for all cohort members. In addition, radiation doses to the thyroid were estimated for the following minor exposure pathways: (a) intake of short-lived 132I, 133I and 132Te by inhalation and ingestion; (b) external irradiation from radionuclides deposited on the ground; and (c) ingestion intake of 134Cs and 137Cs. Intake of 131I was the major pathway for thyroid exposure; its mean contribution to the thyroid dose was 92%. The thyroid doses from 131I intakes varied from 0.5 mGy to almost 33 Gy; the mean was estimated to be 0.58 Gy, while the median was 0.23 Gy. The reconstructed doses are being used to evaluate the risk of thyroid cancer and other thyroid diseases in the cohort. PMID:23560632

  3. [ESTIMATION OF IONIZING RADIATION EFFECTIVE DOSES IN THE INTERNATIONAL SPACE STATION CREWS BY THE METHOD OF CALCULATION MODELING].

    PubMed

    Mitrikas, V G

    2015-01-01

    Monitoring of the radiation loading on cosmonauts requires calculation of absorbed dose dynamics with regard to the stay of cosmonauts in specific compartments of the space vehicle that differ in shielding properties and lack means of radiation measurement. The paper discusses different aspects of calculation modeling of radiation effects on human body organs and tissues and reviews the effective dose estimates for cosmonauts working in one or another compartment over the previous period of the International space station operation. It was demonstrated that doses measured by a real or personal dosimeters can be used to calculate effective dose values. Correct estimation of accumulated effective dose can be ensured by consideration for time course of the space radiation quality factor.

  4. Estimation of Internal Radiation Dose from both Immediate Releases and Continued Exposures to Contaminated Materials

    SciTech Connect

    Napier, Bruce A.

    2012-03-26

    A brief description is provided of the basic concepts related to 'internal dose' and how it differs from doses that result from radioactive materials and direct radiation outside of the body. The principles of radiation dose reconstruction, as applied to both internal and external doses, is discussed based upon a recent publication prepared by the US National Council on Radiation Protection and Measurements. Finally, ideas are introduced related to residual radioactive contamination in the environment that has resulted from the releases from the damaged reactors and also to the management of wastes that may be generated in both regional cleanup and NPP decommissioning.

  5. Estimation of the radiation dose in man due to 6-(/sup 18/F) fluoro-L-dopa

    SciTech Connect

    Harvey, J.; Firnau, G.; Garnett, E.S.

    1985-08-01

    The radiation dose to the organs of the human body after an intravenous administration of 6-(/sup 18/F) fluoro-L-dopa was estimated using the recommendations of the International Committee on Radiological Protection (ICRP). The bladder wall received the highest dose, and as a consequence the dose to the genitalia was high. The major organs received a dose of 5.66E- 12 to 1.87E- 11 Sv/Bq (20 to 60 mrem/mCi). The effective dose equivalent was estimated at 5.39E- 11 Sv/Bq (200 mrem/mCi).

  6. Integrated retrospective radiation dose assessment.

    PubMed

    Goldman, M

    1997-01-01

    Radiation dose reconstruction is used to estimate exposure to radiation that has occurred externally, e.g., from an atomic bomb, or internally, e.g., from radionuclide ingestion. This commentary reviews techniques for biological dosimetry that have been developed to estimate radiation doses from internal exposures, but which can also be used to estimate external exposures. The author argues for increased development and use of these biological tools.

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

    SciTech Connect

    Fellman, A.

    1989-01-01

    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, 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 sacrifice 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.

  8. Magnetic Resonance Imaging-Based Radiation-Absorbed Dose Estimation of {sup 166}Ho Microspheres in Liver Radioembolization

    SciTech Connect

    Seevinck, Peter R.; Maat, Gerrit H. van de; Wit, Tim C. de; Vente, Maarten A.D.; Nijsen, Johannes F.W.; Bakker, Chris J.G.

    2012-07-01

    Purpose: To investigate the potential of magnetic resonance imaging (MRI) for accurate assessment of the three-dimensional {sup 166}Ho activity distribution to estimate radiation-absorbed dose distributions in {sup 166}Ho-loaded poly (L-lactic acid) microsphere ({sup 166}Ho-PLLA-MS) liver radioembolization. Methods and Materials: MRI, computed tomography (CT), and single photon emission CT (SPECT) experiments were conducted on an anthropomorphic gel phantom with tumor-simulating gel samples and on an excised human tumor-bearing liver, both containing known amounts of {sup 166}Ho-PLLA-MS. Three-dimensional radiation-absorbed dose distributions were estimated at the voxel level by convolving the {sup 166}Ho activity distribution, derived from quantitative MRI data, with a {sup 166}Ho dose point-kernel generated by MCNP (Monte Carlo N-Particle transport code) and from Medical Internal Radiation Dose Pamphlet 17. MRI-based radiation-absorbed dose distributions were qualitatively compared with CT and autoradiography images and quantitatively compared with SPECT-based dose distributions. Both MRI- and SPECT-based activity estimations were validated against dose calibrator measurements. Results: Evaluation on an anthropomorphic phantom showed that MRI enables accurate assessment of local {sup 166}Ho-PLLA-MS mass and activity distributions, as supported by a regression coefficient of 1.05 and a correlation coefficient of 0.99, relating local MRI-based mass and activity calculations to reference values obtained with a dose calibrator. Estimated MRI-based radiation-absorbed dose distributions of {sup 166}Ho-PLLA-MS in an ex vivo human liver visually showed high correspondence to SPECT-based radiation-absorbed dose distributions. Quantitative analysis revealed that the differences in local and total amounts of {sup 166}Ho-PLLA-MS estimated by MRI, SPECT, and the dose calibrator were within 10%. Excellent agreement was observed between MRI- and SPECT-based dose

  9. Estimating radiation effective doses from whole body computed tomography scans based on U.S. soldier patient height and weight

    PubMed Central

    2011-01-01

    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. PMID:22004072

  10. Estimation of effective dose and radiation risk in pediatric barium studies procedures.

    PubMed

    Sulieman, A; Elhag, B; Alkhorayef, M; Babikir, E; Theodorou, K; Kappas, C; Bradley, D

    2017-07-21

    The objectives of this study are to assess pediatric radiation exposure in certain barium studies and to quantify the organ and effective doses and radiation risk resultant from patients' irradiation. A total of 69 pediatric barium studies for upper and lower gastrointestinal tract. Patients' radiation dose was quantified in terms of Entrance surface air kerma (ESAKs) using exposure parameters and DosCal software. Organ and effective doses (E) were extrapolated using national Radiological Protection Board software (NRPB-R279). The mean ± (SD) and the range of patient doses per procedure were 3.7 ± 0.4 (1.0-13.0)mGy, 7.4 ± 1.7(5.5-8.0)mGy and 1.4 ± 0.9 (0.5-3.6)mGy for barium meal, swallow and enema, respectively. The mean effective doses were 0.3 ± 0.03 (0.08-1.1)mSv, 0.2 ± 1.6 (0.44-0.7)mSv and 0.3 ± 0.9 (0.1-0.8)mSv at the same order. The radiation dose were higher compared to previous studies. Therefore, pediatrics are exposed to avoidable radiation exposure. Certain optimization measures are recommended along with establishing national diagnostic reference level (DRL) to reduce the radiation risk. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. A proposed simple model for estimating occupational radiation dose to staff from veterinary 18F-FDG pet procedures.

    PubMed

    Martinez, Nicole E; Kraft, Susan L; Johnson, Thomas E

    2014-05-01

    Several studies have been conducted concerning the radiation dose to hospital personnel from positron emission tomography (PET) radiopharmaceuticals, but to date only one parallel study has been conducted for veterinary staff. Veterinary patients present challenges not encountered with human patients, as they require anesthesia and therefore more intensive monitoring than human patients. This paper presents a simple model for estimating the effective radiation dose to veterinary staff using occupational dose data from PET studies at Colorado State University's (CSU) James L. Voss Veterinary Teaching Hospital. The model consists of three point sources within a soft tissue cylinder, and sample calculations are provided for estimating dose to nuclear medicine technologists and an anesthesia technologist based on four different sized dogs. The estimated doses are within the range of actual occupational doses published previously. There are different protocols for the sequence of events in veterinary PET, specifically the order of anesthesia induction and radiopharmaceutical injection. When F-FDG injection is performed prior to anesthesia induction, the estimated dose is between 1.5 and 3.6 times higher than the doses received if injection is done after anesthesia induction, although expected doses for both protocols are below occupational dose limits based on a case load of 100 veterinary patients per year. The model is based on the techniques used at CSU, but it can be modified for different hospitals as well as differently sized animals.

  12. Estimating radiation dose to organs of patients undergoing conventional and novel multidetector CT exams using Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Angel, Erin

    Advances in Computed Tomography (CT) technology have led to an increase in the modality's diagnostic capabilities and therefore its utilization, which has in turn led to an increase in radiation exposure to the patient population. As a result, CT imaging currently constitutes approximately half of the collective exposure to ionizing radiation from medical procedures. In order to understand the radiation risk, it is necessary to estimate the radiation doses absorbed by patients undergoing CT imaging. The most widely accepted risk models are based on radiosensitive organ dose as opposed to whole body dose. In this research, radiosensitive organ dose was estimated using Monte Carlo based simulations incorporating detailed multidetector CT (MDCT) scanner models, specific scan protocols, and using patient models based on accurate patient anatomy and representing a range of patient sizes. Organ dose estimates were estimated for clinical MDCT exam protocols which pose a specific concern for radiosensitive organs or regions. These dose estimates include estimation of fetal dose for pregnant patients undergoing abdomen pelvis CT exams or undergoing exams to diagnose pulmonary embolism and venous thromboembolism. Breast and lung dose were estimated for patients undergoing coronary CTA imaging, conventional fixed tube current chest CT, and conventional tube current modulated (TCM) chest CT exams. The correlation of organ dose with patient size was quantified for pregnant patients undergoing abdomen/pelvis exams and for all breast and lung dose estimates presented. Novel dose reduction techniques were developed that incorporate organ location and are specifically designed to reduce close to radiosensitive organs during CT acquisition. A generalizable model was created for simulating conventional and novel attenuation-based TCM algorithms which can be used in simulations estimating organ dose for any patient model. The generalizable model is a significant contribution of this

  13. UNCERTAINTY ON RADIATION DOSES ESTIMATED BY BIOLOGICAL AND RETROSPECTIVE PHYSICAL METHODS.

    PubMed

    Ainsbury, Elizabeth A; Samaga, Daniel; Della Monaca, Sara; Marrale, Maurizio; Bassinet, Celine; Burbidge, Christopher I; Correcher, Virgilio; Discher, Michael; Eakins, Jon; Fattibene, Paola; Güçlü, Inci; Higueras, Manuel; Lund, Eva; Maltar-Strmecki, Nadica; McKeever, Stephen; Rääf, Christopher L; Sholom, Sergey; Veronese, Ivan; Wieser, Albrecht; Woda, Clemens; Trompier, Francois

    2017-09-18

    Biological and physical retrospective dosimetry are recognised as key techniques to provide individual estimates of dose following unplanned exposures to ionising radiation. Whilst there has been a relatively large amount of recent development in the biological and physical procedures, development of statistical analysis techniques has failed to keep pace. The aim of this paper is to review the current state of the art in uncertainty analysis techniques across the 'EURADOS Working Group 10-Retrospective dosimetry' members, to give concrete examples of implementation of the techniques recommended in the international standards, and to further promote the use of Monte Carlo techniques to support characterisation of uncertainties. It is concluded that sufficient techniques are available and in use by most laboratories for acute, whole body exposures to highly penetrating radiation, but further work will be required to ensure that statistical analysis is always wholly sufficient for the more complex exposure scenarios. © Crown copyright 2017. This article contains public sector information licensed under the Open Government Licence v3.0 (http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/).

  14. Estimation of annual occupational effective doses from external ionizing radiation at medical institutions in Kenya

    NASA Astrophysics Data System (ADS)

    Korir, Geoffrey; Wambani, Jeska; Korir, Ian

    2011-04-01

    This study details the distribution and trends of doses due to occupational radiation exposure among radiation workers from participating medical institutions in Kenya, where monthly dose measurements were collected for a period of one year ranging from January to December in 2007. A total of 367 medical radiation workers were monitored using thermoluminescent dosemeters. They included radiologists (27%), oncologists (2%), dentists (4%), Physicists (5%), technologists (45%), nurses (4%), film processor technicians (3%), auxiliary staff (4%), and radiology office staff (5%). The average annual effective dose of all categories of staff was found to range from 1.19 to 2.52 mSv. This study formed the initiation stage of wider, comprehensive and more frequent monitoring of occupational radiation exposures and long-term investigations into its accumulation patterns in our country.

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

    PubMed

    Lee, Eunsol; Goo, Hyun Woo; Lee, Jae-Yeong

    2015-08-01

    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.

  16. Estimation of occupational cosmic radiation exposure among airline personnel: Agreement between a job-exposure matrix, aggregate, and individual dose estimates.

    PubMed

    Talibov, Madar; Salmelin, Raili; Lehtinen-Jacks, Susanna; Auvinen, Anssi

    2017-04-01

    Job-exposure matrices (JEM) are used for exposure assessment in occupational studies, but they can involve errors. We assessed agreement between the Nordic Occupational Cancer Studies JEM (NOCCA-JEM) and aggregate and individual dose estimates for cosmic radiation exposure among Finnish airline personnel. Cumulative cosmic radiation exposure for 5,022 airline crew members was compared between a JEM and aggregate and individual dose estimates. The NOCCA-JEM underestimated individual doses. Intraclass correlation coefficient was 0.37, proportion of agreement 64%, kappa 0.46 compared with individual doses. Higher agreement was achieved with aggregate dose estimates, that is annual medians of individual doses and estimates adjusted for heliocentric potentials. The substantial disagreement between NOCCA-JEM and individual dose estimates of cosmic radiation may lead to exposure misclassification and biased risk estimates in epidemiological studies. Using aggregate data may provide improved estimates. Am. J. Ind. Med. 60:386-393, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  17. SU-C-12A-05: Radiation Dose in High-Pitch Pediatric Cardiac CTA: Correlation Between Lung Dose and CTDIvol, DLP, and Size Specific Dose Estimates (SSDE)

    SciTech Connect

    Wang, J; Kino, A; Newman, B; Chan, F

    2014-06-01

    Purpose: To investigate the radiation dose for pediatric high pitch cardiac CTA Methods: A total of 14 cases were included in this study, with mean age of 6.2 years (ranges from 2 months to 15 years). Cardiac CTA was performed using a dual-source CT system (Definition Flash, Siemens). Tube voltage (70, 80 and 100kV) was chosen based on patient weight. All patients were scanned using a high-pitch spiral mode (pitch ranges from 2.5 to 3) with tube current modulation technique (CareDose4D, Siemens). For each case, the three dimensional dose distributions were calculated using a Monte Carlo software package (IMPACT-MC, CT Image GmbH). Scanning parameters of each exam, including tube voltage, tube current, beamshaping filters, beam collimation, were defined in the Monte Carlo calculation. Tube current profile along projection angles was obtained from projection data of each tube, which included data within the over-scanning range along z direction. The volume of lungs was segmented out with CT images (3DSlicer). Lung doses of all patients were calculated and compared with CTDIvol, DLP, and SSDE. Results: The average (range) of CTDIvol, DLP and SSDE of all patients was 1.19 mGy (0.58 to 3.12mGy), 31.54 mGy*cm (12.56 to 99 mGy*cm), 2.26 mGy (1.19 to 6.24 mGy), respectively. Radiation dose to the lungs ranged from 0.83 to 4.18 mGy. Lung doses correlated with CTDIvol, DLP and SSDE with correlation coefficients(k) at 0.98, 0.93, and 0.99. However, for the cases with CTDIvol less than 1mGy, only SSDE preserved a strong correlation with lung doses (k=0.83), while much weaker correlations were found for CTDIvol (k=0.29) and DLP (k=-0.47). Conclusion: Lung doses to pediatric patients during Cardiac CTA were estimated. SSDE showed the most robust correlation with lung doses in contrast to CTDIvol and DLP.

  18. A Study on the Establishment of Radiation Dose Estimation Procedure for Accumulated Radioactive Ions for RAON ISOL System

    NASA Astrophysics Data System (ADS)

    KIM, Do Hyun; KIM, Song Hyun; KIM, Jong Woo; SHIN, Chang Ho; NAM, Shin Woo

    2017-09-01

    For purposes of various experiments, RAON heavy ion accelerator facility has been designed in Korea. ISOL is one system of RAON accelerators to generate and separate rare isotopes. Radioactive ions generated from target-proton reactions are separated and accumulated at separation devices. The accumulated isotopes release the gamma radiations; therefore, the radiation safety must be clearly estimated. In this study, a process to evaluate radiations from the accumulated ions was proposed by modifying FISPACT code. The proposed process was validated by comparing a solution of single element decay problem. Using the process, a preliminary study for radiation doses were performed in a virtual separation devise.

  19. Estimating Effective Dose of Radiation From Pediatric Cardiac CT Angiography Using a 64-MDCT Scanner: New Conversion Factors Relating Dose-Length Product to Effective Dose.

    PubMed

    Trattner, Sigal; Chelliah, Anjali; Prinsen, Peter; Ruzal-Shapiro, Carrie B; Xu, Yanping; Jambawalikar, Sachin; Amurao, Maxwell; Einstein, Andrew J

    2017-03-01

    The purpose of this study is to determine the conversion factors that enable accurate estimation of the effective dose (ED) used for cardiac 64-MDCT angiography performed for children. Anthropomorphic phantoms representative of 1- and 10-year-old children, with 50 metal oxide semiconductor field-effect transistor dosimeters placed in organs, underwent scanning performed using a 64-MDCT scanner with different routine clinical cardiac scan modes and x-ray tube potentials. Organ doses were used to calculate the ED on the basis of weighting factors published in 1991 in International Commission on Radiological Protection (ICRP) publication 60 and in 2007 in ICRP publication 103. The EDs and the scanner-reported dose-length products were used to determine conversion factors for each scan mode. The effect of infant heart rate on the ED and the conversion factors was also assessed. The mean conversion factors calculated using the current definition of ED that appeared in ICRP publication 103 were as follows: 0.099 mSv · mGy(-1) · cm(-1), for the 1-year-old phantom, and 0.049 mSv · mGy(-1) · cm(-1), for the 10-year-old phantom. These conversion factors were a mean of 37% higher than the corresponding conversion factors calculated using the older definition of ED that appeared in ICRP publication 60. Varying the heart rate did not influence the ED or the conversion factors. Conversion factors determined using the definition of ED in ICRP publication 103 and cardiac, rather than chest, scan coverage suggest that the radiation doses that children receive from cardiac CT performed using a contemporary 64-MDCT scanner are higher than the radiation doses previously reported when older chest conversion factors were used. Additional up-to-date pediatric cardiac CT conversion factors are required for use with other contemporary CT scanners and patients of different age ranges.

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

    PubMed

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

    2014-05-01

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

  1. Realistic approach to estimate lens doses and cataract radiation risk in cardiology when personal dosimeters have not been regularly used.

    PubMed

    Vañó, Eliseo; Fernández, José M; Sánchez, Roberto M; Dauer, Lawrence T

    2013-10-01

    Interventional fluoroscopic guided cardiac procedures lead to radiation exposure to the lenses of the eyes of cardiologists, which over time may be associated with an increased risk of cataracts. This study derives radiation doses to the lens of the eye in cardiac catheterization laboratories from measurements of individual procedures to allow for estimates of such doses for those cases when personal dosimeters have not been used regularly. Using active electronic dosimeters at the C-arm (at 95 cm from the isocenter), scatter radiation doses have been measured for cardiac procedures and estimated radiation doses to the lenses of the cardiologists for different groups of procedures (diagnostic, PTCAs, and valvular). Correlation factors with kerma area product included in the patient dose reports have been derived. The mean, median, and third quartile scatter dose values per procedure at the C-arm for 1,969 procedures were 0.99, 0.78 and 1.25 mSv, respectively; for coronary angiography, 0.51, 0.45, and 0.61 mSv, respectively; for PTCAs, 1.29, 1.07, and 1.56 mSv; and for valvular procedures, 1.64, 1.45, and 2.66 mSv, respectively. For all the procedures, the ratio between the scatter dose at the C-arm and the kerma area product resulted in between 10.3-11.3 μSv Gy cm. The experimental results of this study allow for realistic estimations of the dose to the lenses of the eyes from the workload of the cardiologists and from the level of use of radiation protection tools when personal dosimeters have not been regularly used.

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

    PubMed

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

    2010-04-01

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

  3. PARMA: PHITS-based Analytical Radiation Model in the Atmosphere--Verification of Its Accuracy in Estimating Cosmic Radiation Doses

    SciTech Connect

    Sato, Tatsuhiko; Satoh, Daiki; Endo, Akira; Yasuda, Hiroshi; Takada, Masashi; Nakamura, Takashi; Niita, Koji; Sihver, Lembit

    2008-08-07

    Estimation of cosmic-ray spectra in the atmosphere has been an essential issue in the evaluation of the aircrew doses. We therefore developed an analytical model that can predict the terrestrial neutron, proton, He nucleus, muon, electron, positron and photon spectra at altitudes below 20 km, based on the Monte Carlo simulation results of cosmic-ray propagation in the atmosphere performed by the PHITS code. The model was designated PARMA. In order to examine the accuracy of PARMA in terms of the neutron dose estimation, we measured the neutron dose rates at the altitudes between 20 to 10400 m, using our developed dose monitor DARWIN mounted on an aircraft. Excellent agreement was observed between the measured dose rates and the corresponding data calculated by PARMA coupled with the fluence-to-dose conversion coefficients, indicating the applicability of the model to be utilized in the route-dose calculation.

  4. PARMA: PHITS-based Analytical Radiation Model in the Atmosphere—Verification of Its Accuracy in Estimating Cosmic Radiation Doses

    NASA Astrophysics Data System (ADS)

    Sato, Tatsuhiko; Yasuda, Hiroshi; Takada, Masashi; Nakamura, Takashi; Satoh, Daiki; Endo, Akira; Niita, Koji; Sihver, Lembit

    2008-08-01

    Estimation of cosmic-ray spectra in the atmosphere has been an essential issue in the evaluation of the aircrew doses. We therefore developed an analytical model that can predict the terrestrial neutron, proton, He nucleus, muon, electron, positron and photon spectra at altitudes below 20 km, based on the Monte Carlo simulation results of cosmic-ray propagation in the atmosphere performed by the PHITS code. The model was designated PARMA. In order to examine the accuracy of PARMA in terms of the neutron dose estimation, we measured the neutron dose rates at the altitudes between 20 to 10400 m, using our developed dose monitor DARWIN mounted on an aircraft. Excellent agreement was observed between the measured dose rates and the corresponding data calculated by PARMA coupled with the fluence-to-dose conversion coefficients, indicating the applicability of the model to be utilized in the route-dose calculation.

  5. Estimation of organs doses and radiation-induced secondary cancer risk from scattered photons for conventional radiation therapy of nasopharynx: a Monte Carlo study.

    PubMed

    Mesbahi, Asghar; Seyednejad, Farshad; Gasemi-Jangjoo, Amir

    2010-06-01

    We used Monte Carlo modeling to calculate the organs doses due to out-of field photons during radiation therapy of the nasopharynx. A medical internal radiation dose (MIRD)-based mathematical phantom resembling an adult man was modeled by MCNP4C MC code. Three validated models of a cobalt-60 machine, a 6-MV photon beam of a Varian 2300 C/D linac, and a 9-MV photon beam of a Neptun linac were used to simulate the isocentric irradiation of a mathematical phantom with two lateral fields of the nasopharynx. The organspecific dose, effective dose, and cancer risk estimates were obtained. The effective doses for out-of-field radiation were 320, 295, and 248 mSv for the (60)Co beam, 6-MV beam, and 9-MV beam devices, respectively, for a 70-Gy tumor dose. The fatal cancer risks of 1.6%, 1.5%, and 1.2% were estimated for a 70-Gy tumor dose of (60)Co and the 6- and 9-MV photon beams, respectively. Our results regarding the effective dose and cancer risk are in agreement with previously published experimental results on conventional radiation therapy. Further investigation on patients' out-of-field dose to provide more knowledge on various radiotherapy techniques is suggested.

  6. Simple Method to Estimate Mean Heart Dose From Hodgkin Lymphoma Radiation Therapy According to Simulation X-Rays

    SciTech Connect

    Nimwegen, Frederika A. van; Cutter, David J.; Schaapveld, Michael; Rutten, Annemarieke; Kooijman, Karen; Krol, Augustinus D.G.; Janus, Cécile P.M.; Darby, Sarah C.; Leeuwen, Flora E. van; Aleman, Berthe M.P.

    2015-05-01

    Purpose: To describe a new method to estimate the mean heart dose for Hodgkin lymphoma patients treated several decades ago, using delineation of the heart on radiation therapy simulation X-rays. Mean heart dose is an important predictor for late cardiovascular complications after Hodgkin lymphoma (HL) treatment. For patients treated before the era of computed tomography (CT)-based radiotherapy planning, retrospective estimation of radiation dose to the heart can be labor intensive. Methods and Materials: Patients for whom cardiac radiation doses had previously been estimated by reconstruction of individual treatments on representative CT data sets were selected at random from a case–control study of 5-year Hodgkin lymphoma survivors (n=289). For 42 patients, cardiac contours were outlined on each patient's simulation X-ray by 4 different raters, and the mean heart dose was estimated as the percentage of the cardiac contour within the radiation field multiplied by the prescribed mediastinal dose and divided by a correction factor obtained by comparison with individual CT-based dosimetry. Results: According to the simulation X-ray method, the medians of the mean heart doses obtained from the cardiac contours outlined by the 4 raters were 30 Gy, 30 Gy, 31 Gy, and 31 Gy, respectively, following prescribed mediastinal doses of 25-42 Gy. The absolute-agreement intraclass correlation coefficient was 0.93 (95% confidence interval 0.85-0.97), indicating excellent agreement. Mean heart dose was 30.4 Gy with the simulation X-ray method, versus 30.2 Gy with the representative CT-based dosimetry, and the between-method absolute-agreement intraclass correlation coefficient was 0.87 (95% confidence interval 0.80-0.95), indicating good agreement between the two methods. Conclusion: Estimating mean heart dose from radiation therapy simulation X-rays is reproducible and fast, takes individual anatomy into account, and yields results comparable to the labor

  7. Simple method to estimate mean heart dose from Hodgkin lymphoma radiation therapy according to simulation X-rays.

    PubMed

    van Nimwegen, Frederika A; Cutter, David J; Schaapveld, Michael; Rutten, Annemarieke; Kooijman, Karen; Krol, Augustinus D G; Janus, Cécile P M; Darby, Sarah C; van Leeuwen, Flora E; Aleman, Berthe M P

    2015-05-01

    To describe a new method to estimate the mean heart dose for Hodgkin lymphoma patients treated several decades ago, using delineation of the heart on radiation therapy simulation X-rays. Mean heart dose is an important predictor for late cardiovascular complications after Hodgkin lymphoma (HL) treatment. For patients treated before the era of computed tomography (CT)-based radiotherapy planning, retrospective estimation of radiation dose to the heart can be labor intensive. Patients for whom cardiac radiation doses had previously been estimated by reconstruction of individual treatments on representative CT data sets were selected at random from a case-control study of 5-year Hodgkin lymphoma survivors (n=289). For 42 patients, cardiac contours were outlined on each patient's simulation X-ray by 4 different raters, and the mean heart dose was estimated as the percentage of the cardiac contour within the radiation field multiplied by the prescribed mediastinal dose and divided by a correction factor obtained by comparison with individual CT-based dosimetry. According to the simulation X-ray method, the medians of the mean heart doses obtained from the cardiac contours outlined by the 4 raters were 30 Gy, 30 Gy, 31 Gy, and 31 Gy, respectively, following prescribed mediastinal doses of 25-42 Gy. The absolute-agreement intraclass correlation coefficient was 0.93 (95% confidence interval 0.85-0.97), indicating excellent agreement. Mean heart dose was 30.4 Gy with the simulation X-ray method, versus 30.2 Gy with the representative CT-based dosimetry, and the between-method absolute-agreement intraclass correlation coefficient was 0.87 (95% confidence interval 0.80-0.95), indicating good agreement between the two methods. Estimating mean heart dose from radiation therapy simulation X-rays is reproducible and fast, takes individual anatomy into account, and yields results comparable to the labor-intensive representative CT-based method. This simpler method may produce a

  8. The cytokinesis-blocked micronucleus assay: dose estimation and inter-individual differences in the response to γ-radiation.

    PubMed

    Antunes, A C; Martins, V; Cardoso, J; Santos, L; Monteiro Gil, O

    2014-01-15

    Biological dosimetry plays an important role in case of a radiation accident or incident, either when it is the only way to estimate the dose or when it is used to complement physical dosimetry. A cytogenetic study was conducted in a group of 16 Portuguese individuals by use of the cytokinesis-blocked micronucleus (CBMN) assay. A dose-response curve for micronuclei yield was established with a linear-quadratic model: Y=(0.0122±0.0010)+(0.0241±0.0023)D+(0.0193±0.0007)D(2). Also, baseline values for the micronucleus formation in the 16 donors were analyzed, with results in close agreement with those from other laboratories. A validation experiment was carried out with three individuals. The real and the estimated doses obtained with the dose-response curve were in very good agreement, allowing the use of the micronucleus dose-response calibration curve in biological dosimetry for estimation of radiation dose in case of overexposure. The results obtained for the cytogenetic endpoints, studied in the same group of 16 individuals, were also analyzed as a function of age and gender. A higher inter-variability was observed for the higher dose points and differences in response were identified between genders, above 2Gy, for all endpoints.

  9. Estimating the Effects of Astronaut Career Ionizing Radiation Dose Limits on Manned Interplanetary Flight Programs

    NASA Technical Reports Server (NTRS)

    Koontz, Steven L.; Rojdev, Kristina; Valle, Gerard D.; Zipay, John J.; Atwell, William S.

    2013-01-01

    The Hybrid Inflatable DSH combined with electric propulsion and high power solar-electric power systems offer a near TRL-now solution to the space radiation crew dose problem that is an inevitable aspect of long term manned interplanetary flight. Spreading program development and launch costs over several years can lead to a spending plan that fits with NASA's current and future budgetary limitations, enabling early manned interplanetary operations with space radiation dose control, in the near future while biomedical research, nuclear electric propulsion and active shielding research and development proceed in parallel. Furthermore, future work should encompass laboratory validation of HZETRN calculations, as previous laboratory investigations have not considered large shielding thicknesses and the calculations presented at these thicknesses are currently performed via extrapolation.

  10. Radiation dosimetry of 18F-FDG PET/CT: incorporating exam-specific parameters in dose estimates.

    PubMed

    Quinn, Brian; Dauer, Zak; Pandit-Taskar, Neeta; Schoder, Heiko; Dauer, Lawrence T

    2016-06-18

    Whole body fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) is the standard of care in oncologic diagnosis and staging, and patient radiation dose must be well understood to balance exam benefits with the risk from radiation exposure. Although reference PET/CT patient doses are available, the potential for widely varying total dose prompts evaluation of clinic-specific patient dose. The aims of this study were to use exam-specific information to characterize the radiation dosimetry of PET/CT exams that used two different CT techniques for adult oncology patients and evaluate the practicality of employing an exam-specific approach to dose estimation. Whole body PET/CT scans from two sets of consecutive adult patients were retrospectively reviewed. One set received a PET scan with a standard registration CT and the other a PET scan with a diagnostic quality CT. PET dose was calculated by modifying the standard reference phantoms in OLINDA/EXM 1.1 with patient-specific organ mass. CT dose was calculated using patient-specific data in ImPACT. International Commission on Radiological Protection publication 103 tissue weighting coefficients were used for effective dose. One hundred eighty three adult scans were evaluated (95 men, 88 women). The mean patient-specific effective dose from a mean injected 18F-FDG activity of 450 ± 32 MBq was 9.0 ± 1.6 mSv. For all standard PET/CT patients, mean effective mAs was 39 ± 11 mAs, mean CT effective dose was 5.0 ± 1.0 mSv and mean total effective dose was 14 ± 1.3 mSv. For all diagnostic PET/CT patients, mean effective mAs was 120 ± 51 mAs, mean CT effective dose was 15.4 ± 5.0 mSv and mean total effective dose was 24.4 ± 4.3 mSv. The five organs receiving the highest organ equivalent doses in all exams were bladder, heart, brain, liver and lungs. Patient-specific parameters optimize the patient dosimetry utilized in the medical justification of

  11. Estimating the Effects of Astronaut Career Ionizing Radiation Dose Limits on Manned Interplanetary Flight Programs

    NASA Technical Reports Server (NTRS)

    Koontz, Steven L.; Rojdev, Kristina; Valle, Gerard D.; Zipay, John J.; Atwell, William S.

    2013-01-01

    Space radiation effects mitigation has been identified as one of the highest priority technology development areas for human space flight in the NASA Strategic Space Technology Investment Plan (Dec. 2012). In this paper we review the special features of space radiation that lead to severe constraints on long-term (more than 180 days) human flight operations outside Earth's magnetosphere. We then quantify the impacts of human space radiation dose limits on spacecraft engineering design and development, flight program architecture, as well as flight program schedule and cost. A new Deep Space Habitat (DSH) concept, the hybrid inflatable habitat, is presented and shown to enable a flexible, affordable approach to long term manned interplanetary flight today.

  12. SU-F-I-33: Estimating Radiation Dose in Abdominal Fat Quantitative CT

    SciTech Connect

    Li, X; Yang, K; Liu, B

    2016-06-15

    Purpose: To compare size-specific dose estimate (SSDE) in abdominal fat quantitative CT with another dose estimate D{sub size,L} that also takes into account scan length. Methods: This study complied with the requirements of the Health Insurance Portability and Accountability Act. At our institution, abdominal fat CT is performed with scan length = 1 cm and CTDI{sub vol} = 4.66 mGy (referenced to body CTDI phantom). A previously developed CT simulation program was used to simulate single rotation axial scans of 6–55 cm diameter water cylinders, and dose integral of the longitudinal dose profile over the central 1 cm length was used to predict the dose at the center of one-cm scan range. SSDE and D{sub size,L} were assessed for 182 consecutive abdominal fat CT examinations with mean water-equivalent diameter (WED) of 27.8 cm ± 6.0 (range, 17.9 - 42.2 cm). Patient age ranged from 18 to 75 years, and weight ranged from 39 to 163 kg. Results: Mean SSDE was 6.37 mGy ± 1.33 (range, 3.67–8.95 mGy); mean D{sub size,L} was 2.99 mGy ± 0.85 (range, 1.48 - 4.88 mGy); and mean D{sub size,L}/SSDE ratio was 0.46 ± 0.04 (range, 0.40 - 0.55). Conclusion: The conversion factors for size-specific dose estimate in AAPM Report No. 204 were generated using 15 - 30 cm scan lengths. One needs to be cautious in applying SSDE to small length CT scans. For abdominal fat CT, SSDE was 80–150% higher than the dose of 1 cm scan length.

  13. Estimation of accumulated dose of radiation by the method of ESR-spectrometry of dental enamel of mammals.

    PubMed

    Serezhenkov, V A; Moroz, I A; Klevezal, G A; Vanin, A F

    1996-01-01

    ESR-spectrometry was used to investigate radiation-induced paramagnetic centers in enamel of mammals: carnivores (polar bear and fox), ungulates (reindeer, European bison, moose), and man. Values at half the microwave power saturation of the radiation signal, P1/2, evaluated at room temperature, was found to range from 16 to 26 mW for animals and man. A new approach to discrimination of the radiation induced signal from the total ESR spectrum of reindeer enamel is proposed. 'Dose-response' dependencies of enamel of different species mammals were measured within the dose range from 0.48 up to 10.08 Gy. Estimations of 'radiosensitivity' enamel of carnivores and ungulates showed good agreement with radiosensitivity enamel of man by ESR method.

  14. Using the Microsoft Kinect for patient size estimation and radiation dose normalization: proof of concept and initial validation.

    PubMed

    Cook, Tessa S; Couch, Gregory; Couch, Timothy J; Kim, Woojin; Boonn, William W

    2013-08-01

    Monitoring patients' imaging-related radiation is currently a hot topic, but there are many obstacles to accurate, patient-specific dose estimation. While some, such as easier access to dose data and parameters, have been overcome, the challenge remains as to how accurately these dose estimates reflect the actual dose received by the patient. The main parameter that is often not considered is patient size. There are many surrogates-weight, body mass index, effective diameter-but none of these truly reflect the three-dimensional "size" of an individual. In this work, we present and evaluate a novel approach to estimating patient volume using the Microsoft Kinect™, a combination RGB camera-infrared depth sensor device. The goal of using this device is to generate a three-dimensional estimate of patient size, in order to more effectively model the dimensions of the anatomy of interest and not only enable better normalization of dose estimates but also promote more patient-specific protocoling of future CT examinations. Preliminary testing and validation of this system reveals good correlation when individuals are standing upright with their arms by their sides, but demonstrates some variation with arm position. Further evaluation and testing is necessary with multiple patient positions and in both adult and pediatric patients. Correlation with other patient size metrics will also be helpful, as the ideal measure of patient "size" may in fact be a combination of existing metrics and newly developed techniques.

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

    PubMed

    Labarta, T

    2007-01-01

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

  16. Estimated radiation dose and image quality comparison of the scan protocols in dual-source computed tomography coronary angiography.

    PubMed

    Karaarslan, Ercan; Ulus, Sıla; Bavbek, Cengiz

    2013-08-01

    Radiation exposure from computed tomography coronary angiography (CTCA) is of particular concern and several techniques have been introduced to lower the radiation dose. In this study, we aimed to compare the diagnostic image quality and estimated radiation dose of the three CTCA acquisition protocols in a recently introduced second generation dual-source computed tomography. Two hundred consecutive subjects underwent dual-source CTCA by using high-pitch spiral, sequential and retrospective spiral protocols. Effective radiation dose, expressed in millisieverts, was calculated as the product of the dose-length product times a conversion factor of 0.014. Image quality was evaluated on a per-segment basis, with a four-point scale. For the high-pitch spiral, sequential and retrospective spiral protocols, mean effective radiation doses were 1.41 ± 0.56, 5.50 ± 2.06 and 7.79 ± 2.25 mSv and mean per-subject image scores were 2.8 ± 0.7, 2.2 ± 0.8 and 2.5 ± 0.8, respectively. Radiation dose of the high-pitch mode was significantly lower (P < 0.001) than the sequential and retrospective spiral modes, and statistical analysis for image quality revealed a significant difference between the high-pitch spiral and the sequential modes (P < 0.05). Dual-source CTCA using high-pitch acquisition considerably lowers radiation exposure in subjects with a low and stable heart rate and maintains good image quality, especially when the subjects have a body mass index ≤25 and a tube voltage of 80 or 100 kV is used. However, when sequential and retrospective spiral modes are used in the same device, mean radiation doses can increase roughly three and five times more, respectively. © 2013 The Authors. Journal of Medical Imaging and Radiation Oncology © 2013 The Royal Australian and New Zealand College of Radiologists.

  17. The children of parents exposed to atomic bombs: estimates of the genetic doubling dose of radiation for humans.

    PubMed Central

    Neel, J V; Schull, W J; Awa, A A; Satoh, C; Kato, H; Otake, M; Yoshimoto, Y

    1990-01-01

    The data collected in Hiroshima and Nagasaki during the past 40 years on the children of survivors of the atomic bombings and on the children of a suitable control population are analyzed on the basis of the newly revised estimates of radiation doses. No statistically significant effects emerge with respect to eight different indicators. Since, however, it may confidently be assumed some mutations were induced, we have taken the data at face value and calculated the minimal gametic doubling doses of acute radiation for the individual indicators at various probability levels. An effort has also been made to calculate the most probable doubling dose for the indicators combined. The latter value is between 1.7 and 2.2 Sv. It is suggested the appropriate figure for chronic radiation would be between 3.4 and 4.5 Sv. These estimates suggest humans are less sensitive to the genetic effects of radiation than has been assumed on the basis of past extrapolations from experiments with mice. PMID:2339701

  18. The children of parents exposed to atomic bombs: Estimates of the genetic doubling dose of radiation for humans

    SciTech Connect

    Neel, J.V.; Schull, W.J.; Awa, A.A.; Satoh, C.; Kato, H.; Otake, M.; Yoshimoto, Y. )

    1990-06-01

    The data collected in Hiroshima and Nagasaki during the past 40 years on the children of survivors of the atomic bombings and on the children of a suitable control population are analyzed on the basis of the newly revised estimates of radiation doses. No statistically significant effects emerge with respect to eight different indicators. Since, however, it may confidently be assumed some mutations were induced, we have taken the data at face value and calculated the minimal gametic doubling doses of acute radiation for the individual indicators at various probability levels. An effort has also been made to calculate the most probable doubling dose for the indicators combined. The latter value is between 1.7 and 2.2 Sv. It is suggested the appropriate figure for chronic radiation would be between 3.4 and 4.5 Sv. These estimates suggest humans are less sensitive to the genetic effects of radiation than has been assumed on the basis of past extrapolations from experiments with mice.

  19. The children of parents exposed to atomic bombs: estimates of the genetic doubling dose of radiation for humans.

    PubMed

    Neel, J V; Schull, W J; Awa, A A; Satoh, C; Kato, H; Otake, M; Yoshimoto, Y

    1990-06-01

    The data collected in Hiroshima and Nagasaki during the past 40 years on the children of survivors of the atomic bombings and on the children of a suitable control population are analyzed on the basis of the newly revised estimates of radiation doses. No statistically significant effects emerge with respect to eight different indicators. Since, however, it may confidently be assumed some mutations were induced, we have taken the data at face value and calculated the minimal gametic doubling doses of acute radiation for the individual indicators at various probability levels. An effort has also been made to calculate the most probable doubling dose for the indicators combined. The latter value is between 1.7 and 2.2 Sv. It is suggested the appropriate figure for chronic radiation would be between 3.4 and 4.5 Sv. These estimates suggest humans are less sensitive to the genetic effects of radiation than has been assumed on the basis of past extrapolations from experiments with mice.

  20. Effect of Anatomical Modeling on Space Radiation Dose Estimates: A Comparison of Doses for NASA Phantoms and 5th, 50th, and 95th Percentile UF Hybrid Phantoms

    NASA Technical Reports Server (NTRS)

    Bahadori, A.; VanBaalen, M.; Shavers, M.; Semones, E.; Dodge, C.; Bolch, W.

    2010-01-01

    The estimate of absorbed dose to individual organs of a space crewmember is affected by the geometry of the anatomical model of the astronaut used in the radiation transport calculation. For astronaut dosimetry, NASA currently uses the computerized anatomical male (CAM) and computerized anatomical female (CAF) stylized phantoms to represent astronauts in its operational radiation dose analyses. These phantoms are available in one size and in two body positions. In contrast, the UF Hybrid Adult Male and Female (UFHADM and UFHADF) phantoms have organ shapes based on actual CT data. The surfaces of these phantoms are defined by non-uniform rational B-spline surfaces, and are thus flexible in terms of body morphometry and extremity positioning. In this study, UFHADM and UFHADF are scaled to dimensions corresponding to 5th, 50th, and 95th percentile (PCTL) male and female astronauts. A ray-tracing program is written in Visual Basic 2008, which is then used to create areal density maps for dose points corresponding to various organs within the phantoms. The areal density maps, along with appropriate space radiation spectra, are input into the NASA program couplet HZETRN/BRYNTRN, and organ doses are calculated. The areal density maps selected tissues and organs of the 5th, 50th, and 95th PCTL male and female phantoms are presented and compared. In addition, the organ doses for the 5th, 50th, and 95th PCTL male and female phantoms are presented and compared to organ doses for CAM and CAF.

  1. Effect of Anatomical Modeling on Space Radiation Dose Estimates: A Comparison of Doses for NASA Phantoms and 5th, 50th, and 95th Percentile UF Hybrid Phantoms

    NASA Technical Reports Server (NTRS)

    Bahadori, A.; VanBaalen, M.; Shavers, M.; Semones, E.; Dodge, C.; Bolch, W.

    2010-01-01

    The estimate of absorbed dose to individual organs of a space crewmember is affected by the geometry of the anatomical model of the astronaut used in the radiation transport calculation. For astronaut dosimetry, NASA currently uses the computerized anatomical male (CAM) and computerized anatomical female (CAF) stylized phantoms to represent astronauts in its operational radiation dose analyses. These phantoms are available in one size and in two body positions. In contrast, the UF Hybrid Adult Male and Female (UFHADM and UFHADF) phantoms have organ shapes based on actual CT data. The surfaces of these phantoms are defined by non-uniform rational B-spline surfaces, and are thus flexible in terms of body morphometry and extremity positioning. In this study, UFHADM and UFHADF are scaled to dimensions corresponding to 5th, 50th, and 95th percentile (PCTL) male and female astronauts. A ray-tracing program is written in Visual Basic 2008, which is then used to create areal density maps for dose points corresponding to various organs within the phantoms. The areal density maps, along with appropriate space radiation spectra, are input into the NASA program couplet HZETRN/BRYNTRN, and organ doses are calculated. The areal density maps selected tissues and organs of the 5th, 50th, and 95th PCTL male and female phantoms are presented and compared. In addition, the organ doses for the 5th, 50th, and 95th PCTL male and female phantoms are presented and compared to organ doses for CAM and CAF.

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

    NASA Astrophysics Data System (ADS)

    Chernov, Anatolii; Shabatura, Olexandr

    2016-04-01

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

  3. Estimation of radiation dose to patients from (18) FDG whole body PET/CT investigations using dynamic PET scan protocol.

    PubMed

    Kaushik, Aruna; Jaimini, Abhinav; Tripathi, Madhavi; D'Souza, Maria; Sharma, Rajnish; Mondal, Anupam; Mishra, Anil K; Dwarakanath, Bilikere S

    2015-12-01

    There is a growing concern over the radiation exposure of patients from undergoing 18FDG PET/CT (18F-fluorodeoxyglucose positron emission tomography/computed tomography) whole body investigations. The aim of the present study was to study the kinetics of 18FDG distributions and estimate the radiation dose received by patients undergoing 18FDG whole body PET/CT investigations. Dynamic PET scans in different regions of the body were performed in 49 patients so as to measure percentage uptake of 18FDG in brain, liver, spleen, adrenals, kidneys and stomach. The residence time in these organs was calculated and radiation dose was estimated using OLINDA software. The radiation dose from the CT component was computed using the software CT-Expo and measured using computed tomography dose index (CTDI) phantom and ionization chamber. As per the clinical protocol, the patients were refrained from eating and drinking for a minimum period of 4 h prior to the study. The estimated residence time in males was 0.196 h (brain), 0.09 h (liver), 0.007 h (spleen), 0.0006 h (adrenals), 0.013 h (kidneys) and 0.005 h (stomach) whereas it was 0.189 h (brain), 0.11 h (liver), 0.01 h (spleen), 0.0007 h (adrenals), 0.02 h (kidneys) and 0.004 h (stomach) in females. The effective dose was found to be 0.020 mSv/MBq in males and 0.025 mSv/MBq in females from internally administered 18FDG and 6.8 mSv in males and 7.9 mSv in females from the CT component. For an administered activity of 370 MBq of 18FDG, the effective dose from PET/CT investigations was estimated to be 14.2 mSv in males and 17.2 mSv in females. The present results did not demonstrate significant difference in the kinetics of 18FDG distribution in male and female patients. The estimated PET/CT doses were found to be higher than many other conventional diagnostic radiology examinations suggesting that all efforts should be made to clinically justify and carefully weigh the risk-benefit ratios prior to every 18FDG whole body PET

  4. Estimation of radiation dose to patients from 18FDG whole body PET/CT investigations using dynamic PET scan protocol

    PubMed Central

    Kaushik, Aruna; Jaimini, Abhinav; Tripathi, Madhavi; D’Souza, Maria; Sharma, Rajnish; Mondal, Anupam; Mishra, Anil K.; Dwarakanath, Bilikere S.

    2015-01-01

    Background & objectives: There is a growing concern over the radiation exposure of patients from undergoing 18FDG PET/CT (18F-fluorodeoxyglucose positron emission tomography/computed tomography) whole body investigations. The aim of the present study was to study the kinetics of 18FDG distributions and estimate the radiation dose received by patients undergoing 18FDG whole body PET/CT investigations. Methods: Dynamic PET scans in different regions of the body were performed in 49 patients so as to measure percentage uptake of 18FDG in brain, liver, spleen, adrenals, kidneys and stomach. The residence time in these organs was calculated and radiation dose was estimated using OLINDA software. The radiation dose from the CT component was computed using the software CT-Expo and measured using computed tomography dose index (CTDI) phantom and ionization chamber. As per the clinical protocol, the patients were refrained from eating and drinking for a minimum period of 4 h prior to the study. Results: The estimated residence time in males was 0.196 h (brain), 0.09 h (liver), 0.007 h (spleen), 0.0006 h (adrenals), 0.013 h (kidneys) and 0.005 h (stomach) whereas it was 0.189 h (brain), 0.11 h (liver), 0.01 h (spleen), 0.0007 h (adrenals), 0.02 h (kidneys) and 0.004 h (stomach) in females. The effective dose was found to be 0.020 mSv/MBq in males and 0.025 mSv/MBq in females from internally administered 18FDG and 6.8 mSv in males and 7.9 mSv in females from the CT component. For an administered activity of 370 MBq of 18FDG, the effective dose from PET/CT investigations was estimated to be 14.2 mSv in males and 17.2 mSv in females. Interpretation & conclusions: The present results did not demonstrate significant difference in the kinetics of 18FDG distribution in male and female patients. The estimated PET/CT doses were found to be higher than many other conventional diagnostic radiology examinations suggesting that all efforts should be made to clinically justify and

  5. Motion-compensated estimation of delivered dose during external beam radiation therapy: implementation in Philips' Pinnacle(3) treatment planning system.

    PubMed

    Bharat, Shyam; Parikh, Parag; Noel, Camille; Meltsner, Michael; Bzdusek, Karl; Kaus, Michael

    2012-01-01

    Recent research efforts investigating dose escalation techniques for three-dimensional conformal radiation therapy (3D CRT) and intensity modulated radiation therapy (IMRT) have demonstrated great benefit when high-dose hypofractionated treatment schemes are implemented. The use of these paradigms emphasizes the importance of smaller treatment margins to avoid high dose to surrounding normal tissue or organs at risk (OARs). However, tighter margins may lead to underdosage of the target due to the presence of organ motion. It is important to characterize organ motion and possibly account for it during treatment delivery. The need for real-time localization of dynamic targets has encouraged the use and development of more continuous motion monitoring systems such as kilo-voltage/fluoroscopic imaging, electromagnetic tracking, and optical monitoring systems. This paper presents the implementation of an algorithm to quantify translational and rotational interfractional and intrafractional prostate motion and compute the dosimetric effects of these motion patterns. The estimated delivered dose is compared with the static plan dose to evaluate the success of delivering the plan in the presence of prostate motion. The method is implemented on a commercial treatment planning system (Pinnacle(3), Philips Radiation Oncology Systems, Philips Healthcare) and is termed delivered dose investigational tool (DiDIT). The DiDIT implementation in Pinnacle(3) is validated by comparisons with previously published results. Finally, different workflows are discussed with respect to the potential use of this tool in clinical treatment planning. The DiDIT dose estimation process took approximately 5-20 min (depending on the number of fractions analyzed) on a Pinnacle(3) 9.100 research version running on a Dell M90 system (Dell, Inc., Round Rock, TX, USA) equipped with an Intel Core 2 Duo processor (Intel Corporation, Santa Clara, CA, USA). The DiDIT implementation in Pinnacle(3) was found

  6. Feasibility of using the computed tomography dose indices to estimate radiation dose to partially and fully irradiated brains in pediatric neuroradiology examinations.

    PubMed

    Januzis, Natalie; Nguyen, Giao; Frush, Donald P; Hoang, Jenny K; Lowry, Carolyn; Yoshizumi, Terry T

    2015-07-21

    The purpose of this study was two-fold: (a) to measure the dose to the brain using clinical protocols at our institution, and (b) to develop a scanner-independent dosimetry method to estimate brain dose. Radiation dose was measured with a pediatric anthropomorphic phantom and MOSFET detectors. Six current neuroradiology protocols were used: brain, sinuses, facial bones, orbits, temporal bones, and craniofacial areas. Two different CT vendor scanners (scanner A and B) were used. Partial volume correction factors (PVCFs) were determined for the brain to account for differences between point doses measured by the MOSFETs and average organ dose. The CTDIvol and DLP for each protocol were recorded. The dose to the brain (mGy) for scanners A and B was 10.7 and 10.0 for the brain protocol, 7.8 and 3.2 for the sinus, 10.2 and 8.6 for the facial bones, 7.4 and 4.7 for the orbits and 1.6 and 1.9 for the temporal bones, respectively. On scanner A, the craniofacial protocol included a standard and high dose option; the dose measured for these exams was 3.9 and 16.9 mGy, respectively. There was only one craniofacial protocol on scanner B; the brain dose measured on this exam was 4.8 mGy. A linear correlation was found between DLP and brain dose with the conversion factors: 0.049 (R(2) = 0.87), 0.046 (R(2) = 0.89) for scanner A and B, and 0.048 (R(2) = 0.89) for both scanners. The range of dose observed was between 1.8 and 16.9 mGy per scan. This suggests that brain dose estimates may be made from DLP.

  7. Feasibility of using the computed tomography dose indices to estimate radiation dose to partially and fully irradiated brains in pediatric neuroradiology examinations

    NASA Astrophysics Data System (ADS)

    Januzis, Natalie; Nguyen, Giao; Frush, Donald P.; Hoang, Jenny K.; Lowry, Carolyn; Yoshizumi, Terry T.

    2015-07-01

    The purpose of this study was two-fold: (a) to measure the dose to the brain using clinical protocols at our institution, and (b) to develop a scanner-independent dosimetry method to estimate brain dose. Radiation dose was measured with a pediatric anthropomorphic phantom and MOSFET detectors. Six current neuroradiology protocols were used: brain, sinuses, facial bones, orbits, temporal bones, and craniofacial areas. Two different CT vendor scanners (scanner A and B) were used. Partial volume correction factors (PVCFs) were determined for the brain to account for differences between point doses measured by the MOSFETs and average organ dose. The CTDIvol and DLP for each protocol were recorded. The dose to the brain (mGy) for scanners A and B was 10.7 and 10.0 for the brain protocol, 7.8 and 3.2 for the sinus, 10.2 and 8.6 for the facial bones, 7.4 and 4.7 for the orbits and 1.6 and 1.9 for the temporal bones, respectively. On scanner A, the craniofacial protocol included a standard and high dose option; the dose measured for these exams was 3.9 and 16.9 mGy, respectively. There was only one craniofacial protocol on scanner B; the brain dose measured on this exam was 4.8 mGy. A linear correlation was found between DLP and brain dose with the conversion factors: 0.049 (R2 = 0.87), 0.046 (R2 = 0.89) for scanner A and B, and 0.048 (R2 = 0.89) for both scanners. The range of dose observed was between 1.8 and 16.9 mGy per scan. This suggests that brain dose estimates may be made from DLP.

  8. Estimation of Observer Performance for Reduced Radiation Dose Levels in CT: Eliminating Reduced Dose Levels That Are Too Low Is the First Step.

    PubMed

    Fletcher, Joel G; Yu, Lifeng; Fidler, Jeff L; Levin, David L; DeLone, David R; Hough, David M; Takahashi, Naoki; Venkatesh, Sudhakar K; Sykes, Anne-Marie G; White, Darin; Lindell, Rebecca M; Kotsenas, Amy L; Campeau, Norbert G; Lehman, Vance T; Bartley, Adam C; Leng, Shuai; Holmes, David R; Toledano, Alicia Y; Carter, Rickey E; McCollough, Cynthia H

    2017-07-01

    This study aims to estimate observer performance for a range of dose levels for common computed tomography (CT) examinations (detection of liver metastases or pulmonary nodules, and cause of neurologic deficit) to prioritize noninferior dose levels for further analysis. Using CT data from 131 examinations (abdominal CT, 44; chest CT, 44; head CT, 43), CT images corresponding to 4%-100% of the routine clinical dose were reconstructed with filtered back projection or iterative reconstruction. Radiologists evaluated CT images, marking specified targets, providing confidence scores, and grading image quality. Noninferiority was assessed using reference standards, reader agreement rules, and jackknife alternative free-response receiver operating characteristic figures of merit. Reader agreement required that a majority of readers at lower dose identify target lesions seen by the majority of readers at routine dose. Reader agreement identified dose levels lower than 50% and 4% to have inadequate performance for detection of hepatic metastases and pulmonary nodules, respectively, but could not exclude any low dose levels for head CT. Estimated differences in jackknife alternative free-response receiver operating characteristic figures of merit between routine and lower dose configurations found that only the lowest dose configurations tested (ie, 30%, 4%, and 10% of routine dose levels for abdominal, chest, and head CT examinations, respectively) did not meet criteria for noninferiority. At lower doses, subjective image quality declined before observer performance. Iterative reconstruction was only beneficial when filtered back projection did not result in noninferior performance. Opportunity exists for substantial radiation dose reduction using existing CT technology for common diagnostic tasks. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  9. A Review of Radiation Protection Requirements and Dose Estimation for Staff and Patients in CT Fluoroscopy.

    PubMed

    Teles, P; Nikodemová, D; Bakhanova, E; Becker, F; Kneževic, Ž; Pereira, M F; Sarmento, S

    2017-05-01

    The combination of fluoroscopically guided interventional procedures with computed tomography (CTF) has become widespread around the world. The benefits of CTF include the ability to obtain a real-time visualization of the entire body, increased target accuracy and improved visualization of biopsy needles. Modern CTF units work with variable frame rates for image selection, and therefore the dose distributions for patients and staff can considerably vary, creating growing concern in terms of the occupational exposure of interventionists and the drawback of a higher exposure of the patient. A literature review of the latest CTF publications is summarized in this article. A wide range of CTF studies reveal different treatment methods used in clinical practice, and therefore the differences in the exposures between them; as well as in the radiation protection tools and dose monitoring. Further optimization of radiation protection methods, harmonization of exposure patterns as well as training and education of CTF staff on the basis of the information in the survey, are strongly recommended. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Estimating radiation doses from multidetector CT using Monte Carlo simulations: effects of different size voxelized patient models on magnitudes of organ and effective dose.

    PubMed

    DeMarco, J J; Cagnon, C H; Cody, D D; Stevens, D M; McCollough, C H; Zankl, M; Angel, E; McNitt-Gray, M F

    2007-05-07

    The purpose of this work is to examine the effects of patient size on radiation dose from CT scans. To perform these investigations, we used Monte Carlo simulation methods with detailed models of both patients and multidetector computed tomography (MDCT) scanners. A family of three-dimensional, voxelized patient models previously developed and validated by the GSF was implemented as input files using the Monte Carlo code MCNPX. These patient models represent a range of patient sizes and ages (8 weeks to 48 years) and have all radiosensitive organs previously identified and segmented, allowing the estimation of dose to any individual organ and calculation of patient effective dose. To estimate radiation dose, every voxel in each patient model was assigned both a specific organ index number and an elemental composition and mass density. Simulated CT scans of each voxelized patient model were performed using a previously developed MDCT source model that includes scanner specific spectra, including bowtie filter, scanner geometry and helical source path. The scan simulations in this work include a whole-body scan protocol and a thoracic CT scan protocol, each performed with fixed tube current. The whole-body scan simulation yielded a predictable decrease in effective dose as a function of increasing patient weight. Results from analysis of individual organs demonstrated similar trends, but with some individual variations. A comparison with a conventional dose estimation method using the ImPACT spreadsheet yielded an effective dose of 0.14 mSv mAs(-1) for the whole-body scan. This result is lower than the simulations on the voxelized model designated 'Irene' (0.15 mSv mAs(-1)) and higher than the models 'Donna' and 'Golem' (0.12 mSv mAs(-1)). For the thoracic scan protocol, the ImPACT spreadsheet estimates an effective dose of 0.037 mSv mAs(-1), which falls between the calculated values for Irene (0.042 mSv mAs(-1)) and Donna (0.031 mSv mAs(-1)) and is higher relative

  11. ESTIMATION OF CARDIAC CT ANGIOGRAPHY RADIATION DOSE TOWARD THE ESTABLISHMENT OF NATIONAL DIAGNOSTIC REFERENCE LEVEL FOR CCTA IN IRAN.

    PubMed

    Hosseini Nasab, Seyed Mohammad Bagher; Shabestani-Monfared, Ali; Deevband, Mohammad Reza; Paydar, Reza; Nabahati, Mehrdad

    2016-08-29

    In recent years, with the introduction of 64-slice CT and dual-source CT technology, coronary CT angiography (CCTA) has emerged as a useful diagnostic imaging modality as a non-invasive assessment of coronary heart disease. CT produces a larger radiation dose than other imaging tests and cardiac CT involves higher radiation dose with the advances in the spatial and temporal resolution. The aims of this study are patient dose assessment and establishment of national diagnostic reference level for CCTA in Iran. A questionnaire was sent to CCTA centers. Data for patient and CT protocols were obtained. The volumetric CT dose index (CTDIvol), dose length product (DLP) and total DLP were considered in the 32 cm standard body phantom. Calculation of estimated effective dose (ED) was obtained by multiplying the DLP by a conversion factor [k = 0.014 mSv (mGy·cm)(-1)]. Mean value of CTDIvol and DLP for CCTA was 50 mGy and 825 mGy·cm. The third quartile (75th) of the distribution of mean CTDIvol (66.54 mGy) and DLP (1073 mGy·cm) values was expressed as the diagnostic reference level (DRL) for CCTA in Iran. The median of ED was 10.26 mSv and interquartile range of ED was 7.08-15.03 mSv. A large variety in CTDIvol and DLP among CT scanner and different sites due to variability in CT parameter is noted. It seems that training could help to reduce patient's dose.

  12. ESTIMATES OF RADIATION DOSES TO THE SKIN FOR PEOPLE CAMPED AT WALLATINNA DURING THE UK TOTEM 1 ATOMIC WEAPONS TEST.

    PubMed

    Williams, G A; O'Brien, R S; Grzechnik, M; Wise, K N

    2017-04-28

    A group of Aboriginal people was camped at Wallatinna in South Australia, ~170 km downwind from Emu Field, where an atomic test (the Totem 1 test) was carried out at 07.00 on 15 October 1953 local time (21.30 on 14 October 1953 GMT (Greenwich Mean Time)). They left the camp ~24 hours later. These people stated that a phenomenon that has become known as a 'black mist' rolled through their camp site ~5 hours after detonation and that some of them subsequently became sick, displaying skin reddening and nausea. They feared that the sickness was a result of exposure to high levels of radiation. The purpose of this paper is to determine if these people could have received ionising radiation doses high enough to cause the symptoms displayed. The methodology used for the dose estimates is described in the paper. The exposure modes considered were external exposure due to the passage of a contaminated plume over the camp site, inhalation of material from this plume, external exposure from material deposited on the ground as the plume passed, and consumption of contaminated food and water. The contaminants considered in the airborne cloud and the ground plume were fission products and unburnt plutonium from the nuclear detonation, and neutron activation products caused by vaporisation of the tower used to position the weapon. The source was approximated by a line source. An upper estimate of the effective doses received is ~4 mSv, which is well below the level at which acute radiation effects are observed. This estimate is consistent with earlier assessments, which did not consider inhalation of the contribution from neutron activation products. © Crown copyright 2016.

  13. Natural radioactivity in various water samples and radiation dose estimations in Bolu province, Turkey.

    PubMed

    Gorur, F Korkmaz; Camgoz, H

    2014-10-01

    The level of natural radioactivity for Bolu province of north-western Turkey was assessed in this study. There is no information about radioactivity measurement reported in water samples in the Bolu province so far. For this reason, gross α and β activities of 55 different water samples collected from tap, spring, mineral, river and lake waters in Bolu were determined. The mean activity concentrations were 68.11 mBq L(-1), 169.44 mBq L(-1) for gross α and β in tap water. For all samples the gross β activity is always higher than the gross α activity. All value of the gross α were lower than the limit value of 500 mBq L(-1) while two spring and one mineral water samples were found to have gross β activity concentrations of greater than 1000 mBq L(-1). The associated age-dependent dose from all water ingestion in Bolu was estimated. The total dose for adults had an average value exceeds the WHO recommended limit value. The risk levels from the direct ingestion of the natural radionuclides in tap and mineral water in Bolu were determinated. The mean (210)Po and (228)Ra risk the value of tap and mineral waters slightly exceeds what some consider on acceptable risk of 10(-4) or less.

  14. Estimation of the radiation dose from radiotherapy for skin haemangiomas in childhood: the ICTA software for epidemiology

    NASA Astrophysics Data System (ADS)

    Shamsaldin, A.; Lundell, M.; Diallo, I.; Ligot, L.; Chavaudra, J.; de Vathaire, F.

    2000-12-01

    Radium applicators and pure beta emitters have been widely used in the past to treat skin haemangioma in early childhood. A well defined relationship between the low doses received from these applicators and radiation-induced cancers requires accurate dosimetry. A human-based CT scan phantom has been used to simulate every patient and treatment condition and then to calculate the source-target distance when radium and pure beta applicators were used. The effective transmission factor ϕ(r) for the gamma spectrum emitted by the radium sources applied on the skin surface was modelled using Monte Carlo simulations. The well-known quantization approach was used to calculate gamma doses delivered from radium applicators to various anatomical points. For 32P, 90Sr/90Y applicators and 90Y needles we have used the apparent exponential attenuation equation. The dose calculation algorithm was integrated into the ICTA software (standing for a model that constructs an Individualized phantom based on CT slices and Auxological data), which has been developed for epidemiological studies of cohorts of patients who received radium and beta-treatments for skin haemangioma. The ϕ(r) values obtained for radium skin applicators are in good agreement with the available values in the first 10 cm but higher at greater distances. Gamma doses can be calculated with this algorithm at 165 anatomical points throughout the body of patients treated with radium applicators. Lung heterogeneity and air crossed by the gamma rays are considered. Comparison of absorbed doses in water from a 10 mg equivalent radium source simulated by ICTA with those measured at the Radiumhemmet, Karolinska Hospital (RAH) showed good agreement, but ICTA estimation of organ doses did not always correspond those estimated at the RAH. Beta doses from 32P, 90Sr/90Y applicators and 90Y needles are calculated up to the maximum beta range (11 mm).

  15. Comparison of the effectiveness of some common animal data scaling techniques in estimating human radiation dose

    SciTech Connect

    Sparks, R.B.; Aydogan, B.

    1999-01-01

    In the development of new radiopharmaceuticals, animal studies are typically performed to get a first approximation of the expected radiation dose in humans. This study evaluates the performance of some commonly used data extrapolation techniques to predict residence times in humans using data collected from animals. Residence times were calculated using animal and human data, and distributions of ratios of the animal results to human results were constructed for each extrapolation method. Four methods using animal data to predict human residence times were examined: (1) using no extrapolation, (2) using relative organ mass extrapolation, (3) using physiological time extrapolation, and (4) using a combination of the mass and time methods. The residence time ratios were found to be log normally distributed for the nonextrapolated and extrapolated data sets. The use of relative organ mass extrapolation yielded no statistically significant change in the geometric mean or variance of the residence time ratios as compared to using no extrapolation. Physiologic time extrapolation yielded a statistically significant improvement (p < 0.01, paired t test) in the geometric mean of the residence time ratio from 0.5 to 0.8. Combining mass and time methods did not significantly improve the results of using time extrapolation alone. 63 refs., 4 figs., 3 tabs.

  16. Radiation absorbed dose estimates for oxygen-15 radiopharmaceuticals (H2( V)O, C VO, O VO) in newborn infants

    SciTech Connect

    Powers, W.J.; Stabin, M.; Howse, D.; Eichling, J.O.; Herscovitch, P.

    1988-12-01

    In preparation for measurement of regional cerebral oxygen metabolism by positron emission tomography, radiation absorbed dose estimates for 19 internal organs, blood, and total body were calculated for newborn infants following bolus intravenous administration of H2( V)O and brief inhalation of C VO and O VO. Cumulated activity for each radiopharmaceutical was calculated from a compartmental model based on the known biologic behavior of the compound. Values for mean absorbed dose/unit cumulated activity (S) for internal organs and total body were based on a newborn phantom. S was separately calculated for blood. Total radiopharmaceutical absorbed dose estimates necessary to measure cerebral oxygen metabolism in a 3.51-kg infant based on 0.7 mCi/kg H2( V)O and 1 mCi/kg C VO and O VO were determined to be 1.6 rad to the lung (maximum organ dose), 0.28 rad to the marrow, 0.46 rad to the gonads, and 0.22 rad to total body. These values are similar to those for current clinical nuclear medicine procedures employing /sup 99m/Tc in newborn infants.

  17. INTDOS: a computer code for estimating internal radiation dose using recommendations of the International Commission on Radiological Protection

    SciTech Connect

    Ryan, M.T.

    1981-09-01

    INTDOS is a user-oriented computer code designed to calculate estimates of internal radiation dose commitment resulting from the acute inhalation intake of various radionuclides. It is designed so that users unfamiliar with the details of such can obtain results by answering a few questions regarding the exposure case. The user must identify the radionuclide name, solubility class, particle size, time since exposure, and the measured lung burden. INTDOS calculates the fractions of the lung burden remaining at time, t, postexposure considering the solubility class and particle size information. From the fraction remaining in the lung at time, t, the quantity inhaled is estimated. Radioactive decay is accounted for in the estimate. Finally, effective committed dose equivalents to various organs and tissues of the body are calculated using inhalation committed dose factors presented by the International Commission on Radiological Protection (ICRP). This computer code was written for execution on a Digital Equipment Corporation PDP-10 computer and is written in Fortran IV. A flow chart and example calculations are discussed in detail to aid the user who is unfamiliar with computer operations.

  18. Estimated radiation dose to breast feeding infant following maternal administration of 57Co labelled to vitamin B12.

    PubMed

    Pomeroy, Kay M; Sawyer, Laura J; Evans, Martyn J

    2005-09-01

    Administration of a radiopharmaceutical may result in a radiation dose to an infant due to ingestion of the radiopharmaceutical secreted in the breast milk. Following a maternal administration of Co labelled to vitamin B12 (cyanocobalamin) as part of a Schilling test an estimate of the absorbed dose to a breast feeding infant was calculated. Milk samples were collected from every feed in the first 24 h, and at approximately 48 and 72 h post-administration. The absorbed dose to the infant's liver (the organ receiving the highest dose) was calculated to be 0.23 mGy. The effective dose to the infant was calculated to be 0.025 mSv, which is considerably lower than the current regulatory limit of 1 mSv. The Administration of Radioactive Substances Advisory Committee advise that the first feed, at approximately 4 h after administration, be discarded. The data show that this was unwarranted, and that the peak concentration of Co in the breast milk occurred at around 24 h.

  19. Prenatal radiation exposure: dose calculation.

    PubMed

    Scharwächter, C; Röser, A; Schwartz, C A; Haage, P

    2015-05-01

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

  20. Repair of sublethal radiation injury after multiple small doses in mouse kidney: an estimate of flexure dose

    SciTech Connect

    Stewart, F.A.; Oussoren, Y.; Luts, A.; Begg, A.C.; Dewit, L.; Lebesque, J.; Bartelink, H.

    1987-05-01

    Functional kidney damage in mice was measured after a series of fractionated X-irradiations. Doses per fraction of 0.75-12.5 Gy were given as 2, 5, 10, 30, 40, 60, or 80 equal doses in a total treatment time of 4 weeks. Renal function (measured by clearance of /sup 51/CrEDTA or hematocrit levels) deteriorated progressively, in a dose related manner, from 20 to 46 weeks after the start of treatment. The changes in renal function versus time were fitted by a polynomial regression through all data and interpolated values for /sup 51/CrEDTA clearance were then calculated at 30 and 40 weeks after treatment. Steep dose response curves were obtained and these were used to calculate isoeffective doses for the different fractionation schedules. There was a marked increase in total isoeffective doses from 2-30 fractions and these data were well described by a linear quadratic (L.Q.) expression for damage with an alpha/beta ratio of 2.3 +/- 0.2 Gy. There was only a slight increase in the total isoeffect dose as the size of the dose per fraction was decreased below 2 Gy and the measured isoeffect doses after 40 to 80 fractions were lower than predicted on the basis of an L.Q. model assuming complete repair between successive irradiations. The flexure dose for mouse kidneys irradiated 3 times per day was, effectively, 1 to 2 Gy and hyperfractionation using lower doses per fraction did not lead to significant, additional repair.

  1. Radiation dose measurements in coronary CT angiography

    PubMed Central

    Sabarudin, Akmal; Sun, Zhonghua

    2013-01-01

    Coronary computed tomography (CT) angiography is associated with high radiation dose and this has raised serious concerns in the literature. Awareness of various parameters for dose estimates and measurements of coronary CT angiography plays an important role in increasing our understanding of the radiation exposure to patients, thus, contributing to the implementation of dose-saving strategies. This article provides an overview of the radiation dose quantity and its measurement during coronary CT angiography procedures. PMID:24392190

  2. An internal radiation dosimetry computer program, IDAC 2.0, for estimation of patient doses from radiopharmaceuticals.

    PubMed

    Andersson, M; Johansson, L; Minarik, D; Mattsson, S; Leide-Svegborn, S

    2014-12-01

    The internal dosimetry computer program internal dose assessment by computer (IDAC) for calculations of absorbed doses to organs and tissues as well as effective doses to patients from examinations with radiopharmaceuticals has been developed. The new version, IDAC2.0, incorporates the International Commission on Radiation Protection (ICRP)/ICRU computational adult male and female voxel phantoms and decay data from the ICRP publication 107. Instead of only 25 source and target regions, calculation can now be made with 63 source regions to 73 target regions. The major advantage of having the new phantom is that the calculations of the effective doses can be made with the latest tissue weighting factors of ICRP publication 103. IDAC2.0 uses the ICRP human alimentary tract (HAT) model for orally administrated activity and for excretion through the gastrointestinal tract and effective doses have been recalculated for radiopharmaceuticals that are orally administered. The results of the program are consistent with published data using the same specific absorption fractions and also compared with published data from the same computational phantoms but with segmentation of organs leading to another set of specific absorption fractions. The effective dose is recalculated for all the 34 radiopharmaceuticals that are administered orally and has been published by the ICRP. Using the new HAT model, new tissue weighting factors and the new adult computational voxel phantoms lead to an average effective dose of half of its earlier estimated value. The reduction mainly depends on electron transport simulations to walled organs and the transition from the stylised phantom with unrealistic interorgan distances to more realistic voxel phantoms.

  3. Bayesian estimation of dose thresholds

    NASA Technical Reports Server (NTRS)

    Groer, P. G.; Carnes, B. A.

    2003-01-01

    An example is described of Bayesian estimation of radiation absorbed dose thresholds (subsequently simply referred to as dose thresholds) using a specific parametric model applied to a data set on mice exposed to 60Co gamma rays and fission neutrons. A Weibull based relative risk model with a dose threshold parameter was used to analyse, as an example, lung cancer mortality and determine the posterior density for the threshold dose after single exposures to 60Co gamma rays or fission neutrons from the JANUS reactor at Argonne National Laboratory. The data consisted of survival, censoring times and cause of death information for male B6CF1 unexposed and exposed mice. The 60Co gamma whole-body doses for the two exposed groups were 0.86 and 1.37 Gy. The neutron whole-body doses were 0.19 and 0.38 Gy. Marginal posterior densities for the dose thresholds for neutron and gamma radiation were calculated with numerical integration and found to have quite different shapes. The density of the threshold for 60Co is unimodal with a mode at about 0.50 Gy. The threshold density for fission neutrons declines monotonically from a maximum value at zero with increasing doses. The posterior densities for all other parameters were similar for the two radiation types.

  4. Radiation dose assessment methodology and preliminary dose estimates to support US Department of Energy radiation control criteria for regulated treatment and disposal of hazardous wastes and materials

    SciTech Connect

    Aaberg, R.L.; Baker, D.A.; Rhoads, K.; Jarvis, M.F.; Kennedy, W.E. Jr.

    1995-07-01

    This report provides unit dose to concentration levels that may be used to develop control criteria for radionuclide activity in hazardous waste; if implemented, these criteria would be developed to provide an adequate level of public and worker health protection, for wastes regulated under U.S, Environmental Protection Agency (EPA) requirements (as derived from the Resource Conservation and Recovery Act [RCRA] and/or the Toxic Substances Control Act [TSCA]). Thus, DOE and the US Nuclear Regulatory Commission can fulfill their obligation to protect the public from radiation by ensuring that such wastes are appropriately managed, while simultaneously reducing the current level of dual regulation. In terms of health protection, dual regulation of very small quantities of radionuclides provides no benefit.

  5. MIRD pamphlet no. 16: Techniques for quantitative radiopharmaceutical biodistribution data acquisition and analysis for use in human radiation dose estimates.

    PubMed

    Siegel, J A; Thomas, S R; Stubbs, J B; Stabin, M G; Hays, M T; Koral, K F; Robertson, J S; Howell, R W; Wessels, B W; Fisher, D R; Weber, D A; Brill, A B

    1999-02-01

    This report describes recommended techniques for radiopharmaceutical biodistribution data acquisition and analysis in human subjects to estimate radiation absorbed dose using the Medical Internal Radiation Dose (MIRD) schema. The document has been prepared in a format to address two audiences: individuals with a primary interest in designing clinical trials who are not experts in dosimetry and individuals with extensive experience with dosimetry-based protocols and calculational methodology. For the first group, the general concepts involved in biodistribution data acquisition are presented, with guidance provided for the number of measurements (data points) required. For those with expertise in dosimetry, highlighted sections, examples and appendices have been included to provide calculational details, as well as references, for the techniques involved. This document is intended also to serve as a guide for the investigator in choosing the appropriate methodologies when acquiring and preparing product data for review by national regulatory agencies. The emphasis is on planar imaging techniques commonly available in most nuclear medicine departments and laboratories. The measurement of the biodistribution of radiopharmaceuticals is an important aspect in calculating absorbed dose from internally deposited radionuclides. Three phases are presented: data collection, data analysis and data processing. In the first phase, data collection, the identification of source regions, the determination of their appropriate temporal sampling and the acquisition of data are discussed. In the second phase, quantitative measurement techniques involving imaging by planar scintillation camera, SPECT and PET for the calculation of activity in source regions as a function of time are discussed. In addition, nonimaging measurement techniques, including external radiation monitoring, tissue-sample counting (blood and biopsy) and excreta counting are also considered. The third phase, data

  6. Weldon Spring historical dose estimate

    SciTech Connect

    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.

  7. Evaluation of Environmental Contamination and Estimated Radiation Doses for the Return to Residents’ Homes in Kawauchi Village, Fukushima Prefecture

    PubMed Central

    Taira, Yasuyuki; Hayashida, Naomi; Yamaguchi, Hitoshi; Yamashita, Shunichi; Endo, Yuukou; Takamura, Noboru

    2012-01-01

    To evaluate the environmental contamination and radiation exposure dose rates due to artificial radionuclides in Kawauchi Village, Fukushima Prefecture, the restricted area within a 30-km radius from the Fukushima Dai-ichi Nuclear Power Plant (FNPP), the concentrations of artificial radionuclides in soil samples, tree needles, and mushrooms were analyzed by gamma spectrometry. Nine months have passed since samples were collected on December 19 and 20, 2011, 9 months after the FNPP accident, and the prevalent dose-forming artificial radionuclides from all samples were 134Cs and 137Cs. The estimated external effective doses from soil samples were 0.42–7.2 µSv/h (3.7–63.0 mSv/y) within the 20-km radius from FNPP and 0.0011–0.38 µSv/h (0.010–3.3 mSv/y) within the 20–30 km radius from FNPP. The present study revealed that current levels are sufficiently decreasing in Kawauchi Village, especially in areas within the 20- to 30-km radius from FNPP. Thus, residents may return their homes with long-term follow-up of the environmental monitoring and countermeasures such as decontamination and restrictions of the intake of foods for reducing unnecessary exposure. The case of Kawauchi Village will be the first model for the return to residents’ homes after the FNPP accident. PMID:23049869

  8. Radiation dose estimates for oral agents used in upper gastrointestinal disease

    SciTech Connect

    Siegel, J.A.; Wu, R.K.; Knight, L.C.; Zelac, R.E.; Stern, H.S.; Malmud, L.S.

    1983-09-01

    Radiation dosimetry was calculated for a number of orally administered radiopharmaceuticals used for study of upper gastrointestinal function. These include: Tc-99m sulfur colloid in water, in a cooked egg, and in chicken liver labeled in vivo; In-111 DTPA; Tc-99m DTPA; In-113m DTPA; Tc-99m ovalbumin in cooked egg; and In-111 colloid in chicken liver labeled in vivo. Radiation burdens to the stomach, small intestine, upper and lower large intestine, ovaries, testes, and total body are calculated for each preparation.

  9. Recommendations to the Technical Steering Panel regarding approach for estimating individual radiation doses resulting from releases of radionuclides to the Columbia River

    SciTech Connect

    Napier, B.A.; Brothers, A.J.

    1992-07-01

    At the direction of the Technical Steering Panel (TSP) of the Hanford Environmental Dose Reconstruction (HEDR) Project, Battelle staff have reviewed and analyzed available data regarding possible historical radiation doses to individuals resulting from radionuclide releases to the Columbia River. The objective of this review was to recommend to the TSP the spatial and temporal scope and level of effort on Columbia River work to most effectively extend work performed in Phase I of the project (PNL 1991a, PNL 1991b) to meet the project objectives. A number of options were analyzed. Four stretches of the Columbia River and adjacent Pacific coastal waters were defined and investigated for four time periods. Radiation doses arising from ten potentially major exposure pathways were evaluated for each of the time/location combinations, and several alternative methods were defined for estimating the doses from each pathway. Preliminary cost estimates were also developed for implementing dose estimation activities for each of the possible combinations.

  10. Residual radionuclide concentrations and estimated radiation doses at the former French nuclear weapons test sites in Algeria.

    PubMed

    Danesi, P R; Moreno, J; Makarewicz, M; Louvat, D

    2008-11-01

    In order to assess the level of residual radioactivity and evaluate the radiological conditions at the former French nuclear testing sites of Reggane and Taourirt Tan Afella in the south of Algeria, the International Atomic Energy Agency, at the request of the government of Algeria, conducted a field mission to the sites in 1999. At these locations, France conducted a number of nuclear tests in the early 1960s. At the ground zero locality of the ''Gerboise Blanche'' atmospheric test (Reggane) and in the vicinity of a tunnel where radioactive lava was ejected during a poorly contained explosion (Taourirt Tan Afella), non-negligible levels of radioactive material could still be measured. Using the information collected and using realistic potential exposure scenarios, radiation doses to potential occupants and visitors to the sites were estimated.

  11. Estimation of internal radiation dose to the adult Asian population from the dietary intakes of two long-lived radionuclides.

    PubMed

    Iyengar, G V; Kawamura, H; Dang, H S; Parr, R M; Wang, J W; Akhter, Perveen; Cho, S Y; Natera, E; Miah, F K; Nguyen, M S

    2004-01-01

    Daily dietary intakes of two naturally occurring long-lived radionuclides, 232Th and 238U, were estimated for the adult population living in a number of Asian countries, using highly sensitive analytical methods such as instrumental and radiochemical neutron activation analysis (INAA and RNAA), and inductively coupled plasma mass spectrometry (ICP-MS). The Asian countries that participated in the study were Bangladesh (BGD), China (CPR), India (IND), Japan (JPN), Pakistan (PAK), Philippines (PHI), Republic of Korea (ROK) and Vietnam (VIE). Altogether, these countries represent more than 50% of the world population. The median daily intakes of 232Th ranged between 0.6 and 14.4 mBq, the lowest being for Philippines and the highest for Bangladesh, and daily intakes of 238U ranged between 6.7 and 62.5 mBq, lowest and the highest being for India and China, respectively. The Asian median intakes were obtained as 4.2 mBq for 232Th and 12.7 mBq for 238U. Although the Asian intakes were lower than intakes of 12.3 mBq (3.0 ug) 232Th and 23.6 mBq (1.9 ug) 238U proposed by the International Commission on Radiological Protection (ICRP) for the ICRP Reference Man, they were comparable to the global intake values of 4.6 mBq 232Th and 15.6 mBq 238U proposed by the United Nation Scientific Commission on Effects of Radiation (UNSCEAR). The annual committed effective doses to Asian population from the dietary intake of 232Th and 238U were calculated to be 0.34 and 0.20 microSv, respectively, which are three orders of magnitude lower than the global average annual radiation dose of 2400 microSv to man from the natural radiation sources as proposed by UNSCEAR.

  12. Improved estimates of the radiation absorbed dose to the urinary bladder wall

    NASA Astrophysics Data System (ADS)

    Andersson, Martin; Minarik, David; Johansson, Lennart; Mattsson, Sören; Leide-Svegborn, Sigrid

    2014-05-01

    Specific absorbed fractions (SAFs) have been calculated as a function of the content in the urinary bladder in order to allow more realistic calculations of the absorbed dose to the bladder wall. The SAFs were calculated using the urinary bladder anatomy from the ICRP male and female adult reference computational phantoms. The urinary bladder and its content were approximated by a sphere with a wall of constant mass, where the thickness of the wall depended on the amount of urine in the bladder. SAFs were calculated for males and females with 17 different urinary bladder volumes from 10 to 800 mL, using the Monte Carlo computer program MCNP5, at 25 energies of mono-energetic photons and electrons ranging from 10 KeV to 10 MeV. The decay was assumed to be homogeneously distributed in the urinary bladder content and the urinary bladder wall, and the mean absorbed dose to the urinary bladder wall was calculated. The Monte Carlo simulations were validated against measurements made with thermoluminescent dosimeters. The SAFs obtained for a urine volume of 200 mL were compared to the values calculated for the urinary bladder wall using the adult reference computational phantoms. The mean absorbed dose to the urinary wall from 18F-FDG was found to be 77 µGy/MBq formales and 86 µGy/MBq for females, while for 99mTc-DTPA the mean absorbed doses were 80 µGy/MBq for males and 86 µGy/MBq for females. Compared to calculations using a constant value of the SAF from the adult reference computational phantoms, the mean absorbed doses to the bladder wall were 60% higher for 18F-FDG and 30% higher for 99mTc-DTPA using the new SAFs.

  13. Improved estimates of the radiation absorbed dose to the urinary bladder wall.

    PubMed

    Andersson, Martin; Minarik, David; Johansson, Lennart; Mattsson, Sören; Leide-Svegborn, Sigrid

    2014-05-07

    Specific absorbed fractions (SAFs) have been calculated as a function of the content in the urinary bladder in order to allow more realistic calculations of the absorbed dose to the bladder wall. The SAFs were calculated using the urinary bladder anatomy from the ICRP male and female adult reference computational phantoms. The urinary bladder and its content were approximated by a sphere with a wall of constant mass, where the thickness of the wall depended on the amount of urine in the bladder. SAFs were calculated for males and females with 17 different urinary bladder volumes from 10 to 800 mL, using the Monte Carlo computer program MCNP5, at 25 energies of mono-energetic photons and electrons ranging from 10 KeV to 10 MeV. The decay was assumed to be homogeneously distributed in the urinary bladder content and the urinary bladder wall, and the mean absorbed dose to the urinary bladder wall was calculated. The Monte Carlo simulations were validated against measurements made with thermoluminescent dosimeters. The SAFs obtained for a urine volume of 200 mL were compared to the values calculated for the urinary bladder wall using the adult reference computational phantoms. The mean absorbed dose to the urinary wall from (18)F-FDG was found to be 77 µGy/MBq formales and 86 µGy/MBq for females, while for (99m)Tc-DTPA the mean absorbed doses were 80 µGy/MBq for males and 86 µGy/MBq for females. Compared to calculations using a constant value of the SAF from the adult reference computational phantoms, the mean absorbed doses to the bladder wall were 60% higher for (18)F-FDG and 30% higher for (99m)Tc-DTPA using the new SAFs.

  14. Radiation dose estimation in computed tomography examinations using NRPB-SR250 software in aretrospective analysis of a patient population.

    PubMed

    Salminen, E; Niiniviita, H; Kulmala, J; Määttänen, H; Järvinen, H

    2012-12-01

    Computed tomography (CT) imaging contributes to a major part of medical radiation exposure. With regard to patients safety, frequent CT examinations (CTEs) performed on the same patient are of particular concern. Tools for tracking the individual patient radiation exposure history and cumulative dose assessment may become important. Here, the applicability of the NRPB-SR250 software was assessed in a retrospective analysis of radiation doses from CTE made consecutively in male patients. Most of the examinations focused on the abdomen or the whole body. The mean number of CTs per patient was 6.8. Significant cumulative effective doses were observed: 76 (66 %) patients received an effective dose higher than 50 mSv, while the maximum was ∼280 mSv. A more than 3-fold effective dose difference was observed between scanners, depending on the scanning protocols. The NRPB-SR250 software proved to be a robust tool for the assessment of organ doses and the effective radiation dose from CT, while challenges were encountered in finding the precise imaging data in retrospective protocols.

  15. Estimation of low-dose radiation-responsive proteins in the absence of genomic instability in normal human fibroblast cells.

    PubMed

    Yim, Ji-Hye; Yun, Jung Mi; Kim, Ji Young; Nam, Seon Young; Kim, Cha Soon

    2017-07-25

    Low-dose radiation has various biological effects such as adaptive responses, low-dose hypersensitivity, as well as beneficial effects. However, little is known about the particular proteins involved in these effects. Here, we sought to identify low-dose radiation-responsive phosphoproteins in normal fibroblast cells. We assessed genomic instability and proliferation of fibroblast cells after γ-irradiation by γ-H2AX foci and micronucleus formation analyses and BrdU incorporation assay, respectively. We screened fibroblast cells 8 h after low-dose (0.05 Gy) γ-irradiation using Phospho Explorer Antibody Microarray and validated two differentially expressed phosphoproteins using Western blotting. Cell proliferation proceeded normally in the absence of genomic instability after low-dose γ-irradiation. Phospho antibody microarray analysis and Western blotting revealed increased expression of two phosphoproteins, phospho-NFκB (Ser536) and phospho-P70S6K (Ser418), 8 h after low-dose radiation. Our findings suggest that low-dose radiation of normal fibroblast cells activates the expression of phospho-NFκB (Ser536) and phospho-P70S6K (Ser418) in the absence of genomic instability. Therefore, these proteins may be involved in DNA damage repair processes.

  16. Personalized estimates of radiation dose from dedicated breast CT in a diagnostic population and comparison with diagnostic mammography

    PubMed Central

    Vedantham, Srinivasan; Shi, Linxi; Karellas, Andrew; O’Connell, Avice M.; Conover, David L.

    2013-01-01

    lower than diagnostic mammography, the median MGD from dedicated breast CT was approximately 13.5% higher than that from diagnostic mammography. The MGD for breast CT is based on a 1.45 mm skin layer and that for diagnostic mammography is based on a 4 mm skin layer; thus, favoring a lower estimate for MGD from diagnostic mammography. The median MGD from dedicated breast CT corresponds to the median MGD from 4 to 5 diagnostic mammography views. In comparison, for the same 133 breasts, the mean and the median number of views per breast during diagnostic mammography were 4.53 and 4, respectively. Paired analysis showed that there was approximately equal likelihood of receiving lower MGD from either breast CT or diagnostic mammography. Future work will investigate methods to reduce and optimize radiation dose from dedicated breast CT. PMID:24165162

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

    SciTech Connect

    Cohen, N.

    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.

  18. Personalized estimates of radiation dose from dedicated breast CT in a diagnostic population and comparison with diagnostic mammography.

    PubMed

    Vedantham, Srinivasan; Shi, Linxi; Karellas, Andrew; O'Connell, Avice M; Conover, David L

    2013-11-21

    diagnostic mammography, the median MGD from dedicated breast CT was approximately 13.5% higher than that from diagnostic mammography. The MGD for breast CT is based on a 1.45 mm skin layer and that for diagnostic mammography is based on a 4 mm skin layer; thus, favoring a lower estimate for MGD from diagnostic mammography. The median MGD from dedicated breast CT corresponds to the median MGD from four to five diagnostic mammography views. In comparison, for the same 133 breasts, the mean and the median number of views per breast during diagnostic mammography were 4.53 and 4, respectively. Paired analysis showed that there was approximately equal likelihood of receiving lower MGD from either breast CT or diagnostic mammography. Future work will investigate methods to reduce and optimize radiation dose from dedicated breast CT.

  19. Personalized estimates of radiation dose from dedicated breast CT in a diagnostic population and comparison with diagnostic mammography

    NASA Astrophysics Data System (ADS)

    Vedantham, Srinivasan; Shi, Linxi; Karellas, Andrew; O'Connell, Avice M.; Conover, David L.

    2013-11-01

    diagnostic mammography, the median MGD from dedicated breast CT was approximately 13.5% higher than that from diagnostic mammography. The MGD for breast CT is based on a 1.45 mm skin layer and that for diagnostic mammography is based on a 4 mm skin layer; thus, favoring a lower estimate for MGD from diagnostic mammography. The median MGD from dedicated breast CT corresponds to the median MGD from four to five diagnostic mammography views. In comparison, for the same 133 breasts, the mean and the median number of views per breast during diagnostic mammography were 4.53 and 4, respectively. Paired analysis showed that there was approximately equal likelihood of receiving lower MGD from either breast CT or diagnostic mammography. Future work will investigate methods to reduce and optimize radiation dose from dedicated breast CT.

  20. Direct estimates of cancer mortality due to low doses of ionising radiation: an international study. IARC Study Group on Cancer Risk among Nuclear Industry Workers.

    PubMed

    1994-10-15

    When setting standards for protection against ionising radiation it has been usual to extrapolate from experience with high-dose short-term exposure--studies based on atom bomb survivors and patients exposed to radiation therapeutically. Those who work in the nuclear industry are exposed to low-level predominantly gamma radiation for longer periods, and provide an alternative direct source of information. We have combined mortality data from seven cohort studies on nearly 96,000 nuclear industry workers monitored for external radiation in Canada, UK, and USA to assess directly the carcinogenic effects of protracted low-dose exposure to ionising radiation. The excess relative risk for death from leukaemia, excluding chronic lymphocytic leukaemia, was 2.2 per Sv (90% Cl 0.1 to 5.7). This estimate is intermediate between the linear estimate of 3.7 per Sv and the linear-quadratic estimate (as used in recent leukaemia risk assessments) of 1.4 per Sv derived from Japanese atomic bomb survivors' data. The excess relative risk for death from all cancers, excluding leukaemia, was -0.07 per Sv (90% Cl -0.4 to 0.3). This estimate is consistent with a range of risks varying from negative to nearly twice those estimated from atomic bomb survivors (0.18 per Sv). These are the most precise direct estimates so far made of carcinogenic risk after protracted exposure to low-dose ionising radiation. They provide little evidence that the estimates that form the basis of current radiation protection recommendations are appreciably in error.

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

    PubMed

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

    2008-08-01

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

  2. [A new approach to shielding function calculation: radiation dose estimation for a phantome inside space station compartment].

    PubMed

    Kartashov, D A; Shurshakov, V A

    2012-01-01

    The article presents a new procedure of calculating the shielding functions for irregular objects formed from a set of nonintersecting (adjacent) triangles covering completely the surface of each object. Calculated and experimentally derived distributions of space ionizing radiation doses in the spherical tissue-equivalent phantom (experiment MATRYOSHKA-R) inside the International space station were in good agreement in the mass of phantom depths with allowance for measurement error (-10%). The procedure can be applied in modeling radiation loads on cosmonauts, calculating effectiveness of secondary protection in spacecraft, and design review of radiation protection for future space exploration missions.

  3. Estimation of the Dose and Dose Rate Effectiveness Factor

    NASA Technical Reports Server (NTRS)

    Chappell, L.; Cucinotta, F. A.

    2013-01-01

    Current models to estimate radiation risk use the Life Span Study (LSS) cohort that received high doses and high dose rates of radiation. Transferring risks from these high dose rates to the low doses and dose rates received by astronauts in space is a source of uncertainty in our risk calculations. The solid cancer models recommended by BEIR VII [1], UNSCEAR [2], and Preston et al [3] is fitted adequately by a linear dose response model, which implies that low doses and dose rates would be estimated the same as high doses and dose rates. However animal and cell experiments imply there should be curvature in the dose response curve for tumor induction. Furthermore animal experiments that directly compare acute to chronic exposures show lower increases in tumor induction than acute exposures. A dose and dose rate effectiveness factor (DDREF) has been estimated and applied to transfer risks from the high doses and dose rates of the LSS cohort to low doses and dose rates such as from missions in space. The BEIR VII committee [1] combined DDREF estimates using the LSS cohort and animal experiments using Bayesian methods for their recommendation for a DDREF value of 1.5 with uncertainty. We reexamined the animal data considered by BEIR VII and included more animal data and human chromosome aberration data to improve the estimate for DDREF. Several experiments chosen by BEIR VII were deemed inappropriate for application to human risk models of solid cancer risk. Animal tumor experiments performed by Ullrich et al [4], Alpen et al [5], and Grahn et al [6] were analyzed to estimate the DDREF. Human chromosome aberration experiments performed on a sample of astronauts within NASA were also available to estimate the DDREF. The LSS cohort results reported by BEIR VII were combined with the new radiobiology results using Bayesian methods.

  4. An influential factor for external radiation dose estimation for residents after the Fukushima Daiichi Nuclear Power Plant accident-time spent outdoors for residents in Iitate Village.

    PubMed

    Ishikawa, Tetsuo; Yasumura, Seiji; Ohtsuru, Akira; Sakai, Akira; Akahane, Keiichi; Yonai, Shunsuke; Sakata, Ritsu; Ozasa, Kotaro; Hayashi, Masayuki; Ohira, Tetsuya; Kamiya, Kenji; Abe, Masafumi

    2016-06-01

    Many studies have been conducted on radiation doses to residents after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. Time spent outdoors is an influential factor for external dose estimation. Since little information was available on actual time spent outdoors for residents, different values of average time spent outdoors per day have been used in dose estimation studies on the FDNPP accident. The most conservative value of 24 h was sometimes used, while 2.4 h was adopted for indoor workers in the UNSCEAR 2013 report. Fukushima Medical University has been estimating individual external doses received by residents as a part of the Fukushima Health Management Survey by collecting information on the records of moves and activities (the Basic Survey) after the accident from each resident. In the present study, these records were analyzed to estimate an average time spent outdoors per day. As an example, in Iitate Village, its arithmetic mean was 2.08 h (95% CI: 1.64-2.51) for a total of 170 persons selected from respondents to the Basic Survey. This is a much smaller value than commonly assumed. When 2.08 h is used for the external dose estimation, the dose is about 25% (23-26% when using the above 95% CI) less compared with the dose estimated for the commonly used value of 8 h.

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

    SciTech Connect

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

    2011-01-15

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

  6. Application of computational models to estimate organ radiation dose in rainbow trout from uptake of molybdenum-99 with comparison to iodine-131.

    PubMed

    Martinez, N E; Johnson, T E; Pinder, J E

    2016-01-01

    This study compares three anatomical phantoms for rainbow trout (Oncorhynchus mykiss) for the purpose of estimating organ radiation dose and dose rates from molybdenum-99 ((99)Mo) uptake in the liver and GI tract. Model comparison and refinement is important to the process of determining accurate doses and dose rates to the whole body and the various organs. Accurate and consistent dosimetry is crucial to the determination of appropriate dose-effect relationships for use in environmental risk assessment. The computational phantoms considered are (1) a geometrically defined model employing anatomically relevant organ size and location, (2) voxel reconstruction of internal anatomy obtained from CT imaging, and (3) a new model utilizing NURBS surfaces to refine the model in (2). Dose Conversion Factors (DCFs) for whole body as well as selected organs of O. mykiss were computed using Monte Carlo modeling and combined with empirical models for predicting activity concentration to estimate dose rates and ultimately determine cumulative radiation dose (μGy) to selected organs after several half-lives of (99)Mo. The computational models provided similar results, especially for organs that were both the source and target of radiation (less than 30% difference between all models). Values in the empirical model as well as the 14 day cumulative organ doses determined from (99)Mo uptake are compared to similar models developed previously for (131)I. Finally, consideration is given to treating the GI tract as a solid organ compared to partitioning it into gut contents and GI wall, which resulted in an order of magnitude difference in estimated dose for most organs.

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

    SciTech Connect

    Amundson, Sally A.

    2013-06-12

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

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

    PubMed

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

    2016-09-01

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

  9. Use of PET for estimation of radiation dose variations within the thyroid from radioiodine therapy in thyrotoxic patients

    SciTech Connect

    Ott, R.J.; Batty, V.; Clack, R.; Flower, M.A.; Leach, M.O.; Marsden, P.; McCready, V.R.; Webb, S.

    1985-05-01

    A series of 22 patients have been studied using a prototype Multiwire Proportional Chamber Positron Camera to determine the accuracy of measurement of thyroid uptake of radioiodine. The patients being treated for thyrotoxicosis were given a solution containing 1.5 mCi of I-131 and 0.7 mCi of I-124. In a few case 0.3 mCi of I-124 was given prior to I-131 therapy. Data acquisition consisted of 8 contiguous views of the thyroid covering the full 360 degrees around the patient. Each study contained approximately 400,000 events. Data analysis consisted of a simple backprojection and 3D deconvolution of the point source response function to produce a 64x64x64 volume matrix using 0.27ml voxels. The volume of the thyroid was obtained using a simple thresholding technique to determine the number of voxels within the thyroid. Phantom measurements show that the functional volume and hence the radiation dose to the thyroid can be estimated to approx. =10%. From conventional imaging with a gamma camera plus pinhole collimator, 18 out of 22 patients were diagnosed as having uniform Graves disease. The high resolution tomographic information provided by PET imaging has shown that the uptake in 5 of these 18 patients was multinodular. In one case the volume of the nodules within the thyroid was estimated to be 45% of the organ volume. This non-uniform uptake of iodine within the thyroid has consequences for the overall management of hyperthyroidism in patients thought to have Graves disease. It may in part explain the cases of unexpected post therapy hypothyroidism.

  10. Comparison of the COMRADEX-IV and AIRDOS-EPA methodologies for estimating the radiation dose to man from radionuclide releases to the atmosphere

    SciTech Connect

    Miller, C.W.; Hoffman, F.O.; Dunning, D.E. Jr.

    1981-01-01

    This report presents a comparison between two computerized methodologies for estimating the radiation dose to man from radionuclide releases to the atmosphere. The COMRADEX-IV code was designed to provide a means of assessing potential radiological consequences from postulated power reactor accidents. The AIRDOS-EPA code was developed primarily to assess routine radionuclide releases from nuclear facilities. Although a number of different calculations are performed by these codes, three calculations are in common - atmospheric dispersion, estimation of internal dose from inhalation, and estimation of external dose from immersion in air containing gamma emitting radionuclides. The models used in these calculations were examined and found, in general, to be the same. Most differences in the doses calculated by the two codes are due to differences in values chosen for input parameters and not due to model differences. A sample problem is presented for illustration.

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

    SciTech Connect

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

    1982-02-01

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

  12. Radiation dose to the global flying population.

    PubMed

    Alvarez, Luis E; Eastham, Sebastian D; Barrett, Steven R H

    2016-03-01

    Civil airliner passengers and crew are exposed to elevated levels of radiation relative to being at sea level. Previous studies have assessed the radiation dose received in particular cases or for cohort studies. Here we present the first estimate of the total radiation dose received by the worldwide civilian flying population. We simulated flights globally from 2000 to 2013 using schedule data, applying a radiation propagation code to estimate the dose associated with each flight. Passengers flying in Europe and North America exceed the International Commission on Radiological Protection annual dose limits at an annual average of 510 or 420 flight hours per year, respectively. However, this falls to 160 or 120 h on specific routes under maximum exposure conditions.

  13. On-line estimations of delivered radiation doses in three-dimensional conformal radiotherapy treatments of carcinoma uterine cervix patients in linear accelerator

    PubMed Central

    Putha, Suman Kumar; Saxena, P. U.; Banerjee, S.; Srinivas, Challapalli; Vadhiraja, B. M.; Ravichandran, Ramamoorthy; Joan, Mary; Pai, K. Dinesh

    2016-01-01

    Transmission of radiation fluence through patient's body has a correlation to the planned target dose. A method to estimate the delivered dose to target volumes was standardized using a beam level 0.6 cc ionization chamber (IC) positioned at electronic portal imaging device (EPID) plane from the measured transit signal (St) in patients with cancer of uterine cervix treated with three-dimensional conformal radiotherapy (3DCRT). The IC with buildup cap was mounted on linear accelerator EPID frame with fixed source to chamber distance of 146.3 cm, using a locally fabricated mount. Sts were obtained for different water phantom thicknesses and radiation field sizes which were then used to generate a calibration table against calculated midplane doses at isocenter (Diso,TPS), derived from the treatment planning system. A code was developed using MATLAB software which was used to estimate the in vivo dose at isocenter (Diso,Transit) from the measured Sts. A locally fabricated pelvic phantom validated the estimations of Diso,Transit before implementing this method on actual patients. On-line dose estimations were made (3 times during treatment for each patient) in 24 patients. The Diso,Transit agreement with Diso,TPS in phantom was within 1.7% and the mean percentage deviation with standard deviation is −1.37% ±2.03% (n = 72) observed in patients. Estimated in vivo dose at isocenter with this method provides a good agreement with planned ones which can be implemented as part of quality assurance in pelvic sites treated with simple techniques, for example, 3DCRT where there is a need for documentation of planned dose delivery. PMID:28144114

  14. Analysis of various aspects of atomic bomb dose estimation at RERF using data on acute radiation symptoms. [Data on subjects in Hiroshima and Nagasaki

    SciTech Connect

    Gilbert, E.S.; Ohara, J.L.

    1984-01-01

    The dose-response curves for acute radiation symptoms reported by atomic bomb survivors are compared by dose estimation method (the method used to calculate the transmission factor), shielding category, and city. Circular symmetry is also investigated. It is found that response rates for acute symptoms differ considerably by dose estimation method and shielding category even after controlling for both ..gamma.. and neutron exposure as well as for city, sex, and age at the time of the bomb. One explanation of these results is that the doses of survivors in Japanese type houses estimated by the nine parameter method are subject to less random measurement error, while doses of those survivors who were in the open and shielded by terrain, who were totally shielded by concrete buildings, and who were in factories are subject to especially large random errors. The degree to which systematic bias contributes to these differences could not be determined. These results have important implications for comparisons between cities since Nagasaki includes a far greater proportion of survivors in shielding categories showing weak dose-response relationships than does Hiroshima. The hypothesis that doses might be higher in the westerly direction in Hiroshima is not supported by acute effects analyses, but excess acute effects are found in the north of Hiroshima.

  15. Establishing cytogenetic biodosimetry laboratory in Saudi Arabia and producing preliminary calibration curve of dicentric chromosomes as biomarker for medical dose estimation in response to radiation emergencies.

    PubMed

    Al-Hadyan, Khaled; Elewisy, Sara; Moftah, Belal; Shoukri, Mohamed; Alzahrany, Awad; Alsbeih, Ghazi

    2014-12-01

    In cases of public or occupational radiation overexposure and eventual radiological accidents, it is important to provide dose assessment, medical triage, diagnoses and treatment to victims. Cytogenetic bio-dosimetry based on scoring of dicentric chromosomal aberrations assay (DCA) is the "gold standard" biotechnology technique for estimating medically relevant radiation doses. Under the auspices of the National Science, Technology and Innovation Plan in Saudi Arabia, we have set up a biodosimetry laboratory and produced a national standard dose-response calibration curve for DCA, pre-required to estimate the doses received. For this, the basic cytogenetic DCA technique needed to be established. Peripheral blood lymphocytes were collected from four healthy volunteers and irradiated with radiation doses between 0 and 5 Gy of 320 keV X-rays. Then, lymphocytes were PHA stimulated, Colcemid division arrested and stained cytogenetic slides were prepared. The Metafer4 system (MetaSystem) was used for automatic and manually assisted metaphase finding and scoring of dicentric chromosomes. Results were fit to the linear-quadratic dose-effect model according to the IAEA EPR-Biodosimetry-2011 report. The resulting manually assisted dose-response calibration curve (Y = 0.0017 + 0.026 × D + 0.081 × D(2)) was in the range of those described in other populations. Although the automated scoring over-and-under estimates DCA at low (<1 Gy) and high (>2 Gy) doses, respectively, it showed potential for use in triage mode to segregate between victims with potential risk to develop acute radiotoxicity syndromes. In conclusion, we have successfully established the first biodosimetry laboratory in the region and have produced a preliminary national dose-response calibration curve. The laboratory can now contribute to the national preparedness plan in response to eventual radiation emergencies in addition to providing information for decision makers and public health

  16. Dose estimation by ESR on tooth enamel from two workers exposed to radiation due to the JCO accident.

    PubMed

    Shiraishi, Kunio; Iwasaki, Midori; Miyazawa, Chyuzo; Yonehara, Hidenori; Matsumoto, Masaki

    2002-09-01

    ESR dosimetry is useful to estimate the external dose for the general population as well as for occupational workers in a nuclear emergency. Three teeth were extracted from two exposed workers (A and B) related to the JCO criticality accident. Tooth enamel was carefully separated from other tooth parts and subjected to ESR dosimetry. Doses equivalent to the gamma-ray dose of 60Co were estimated as follows: for worker A, the buccal and lingual sides of the eighth tooth in the upper right side, 11.8 +/- 3.6 and 12.0 +/- 3.6 Gy, respectively; for worker B, the buccal and lingual sides of the fourth tooth in the upper right side and the fifth tooth in the upper left side, 11.3 +/- 3.4 and 10.8 +/- 3.3 Gy, 11.7 +/- 3.5 and 11.4 +/- 3.4 Gy, respectively. The estimated doses were found to be similar and not dependent on the tooth positions, whether the buccal or lingual sides in each tooth.

  17. Current activities in the ICRP concerning estimation of radiation doses to patients from radiopharmaceuticals for diagnostic use

    NASA Astrophysics Data System (ADS)

    Mattsson, S.; Johansson, L.; Leide-Svegborn, S.; Liniecki, J.; Nosske, D.; Riklund, K.; Stabin, M.; Taylor, D.

    2011-09-01

    A Task Group within the ICRP Committees 2 and 3 is continuously working to improve absorbed dose estimates to patients investigated with radiopharmaceuticals. The work deals with reviews of the literature, initiation of new or complementary studies of the biokinetics of a compound and dose estimates. Absorbed dose calculations for organs and tissues have up to now been carried out using the MIRD formalism. There is still a lack of necessary biokinetic data from measurements in humans. More time series obtained by nuclear medicine imaging techniques such as whole-body planar gamma-camera imaging, SPECT or PET are highly desirable for this purpose. In 2008, a new addendum to ICRP Publication 53 was published under the name of ICRP Publication 106 containing biokinetic data and absorbed dose information to organs and tissues of patients of various ages for radiopharmaceuticals in common use. That report also covers a number of generic models and realistic maximum models covering other large groups of substances (e.g. "123I-brain receptor substances"). Together with ICRP Publication 80, most radiopharmaceuticals in clinical use at the time of publication were covered except the radioiodine labeled compounds for which the ICRP dose estimates are still found in Publication 53. There is an increasing use of new radiopharmaceuticals, especially PET-tracers and the TG has recently finished its work with biokinetic and dosimetric data for 18F-FET, 18F-FLT and 18F-choline. The work continues now with new data for 11C-raclopride, 11C-PiB and 123I-ioflupan as well as re-evaluation of published data for 82Rb-chloride, 18F-fluoride and radioiodide. This paper summarises published ICRP-information on dose to patients from radiopharmaceuticals and gives some preliminary data for substances under review.

  18. Radiation-dose estimates and hazard evaluations for inhaled airborne radionuclides. Annual progress report, July 1981-June 1982

    SciTech Connect

    Mewhinney, J.A.

    1983-06-01

    The objective was to conduct confirmatory research on aerosol characteristics and the resulting radiation dose distribution in animals following inhalation and to provide prediction of health consequences in humans due to airborne radioactivity which might be released in normal operations or under accident conditions during production of nuclear fuel composed of mixed oxides of U and Pu. Four research reports summarize the results of specific areas of research. The first paper details development of a method for determination of specific surface area of small samples of mixed oxide or pure PuO/sub 2/ particles. The second paper details the extension of the biomathematical model previously used to describe retention, distribution and excretion of Pu from these mixed oxide aerosols to include a description of Am and U components of these aerosols. The third paper summarizes the biological responses observed in radiation dose pattern studies in which dogs, monkeys and rate received inhalation exposures to either 750/sup 0/C heat treated UO/sub 2/ + PuO/sub 2/, 1750/sup 0/C heat-treated (U,Pu)O/sub 2/ or 850/sup 0/C heat-treated pure PuO/sub 2/. The fourth paper described dose-response studies in which rats were exposed to (U,Pu)O/sub 2/ or pure PuO/sub 2/. This paper updates earlier reports and summarizes the status of animals through approximately 650 days after inhalation.

  19. Radiation dose in dental radiology.

    PubMed

    Cohnen, M; Kemper, J; Möbes, O; Pawelzik, J; Mödder, U

    2002-03-01

    The aim of this study was to compare radiation exposure in panoramic radiography (PR), dental CT, and digital volume tomography (DVT). An anthropomorphic Alderson-Rando phantom and two anatomical head phantoms with thermoluminescent dosimeters fixed at appropriate locations were exposed as in a dental examination. In PR and DVT, standard parameters were used while variables in CT included mA, pitch, and rotation time. Image noise was assessed in dental CT and DVT. Radiation doses to the skin and internal organs within the primary beam and resulting from scatter radiation were measured and expressed as maximum doses in mGy. For PR, DVT, and CT, these maximum doses were 0.65, 4.2, and 23 mGy. In dose-reduced CT protocols, radiation doses ranged from 10.9 to 6.1 mGy. Effective doses calculated on this basis showed values below 0.1 mSv for PR, DVT, and dose-reduced CT. Image noise was similar in DVT and low-dose CT. As radiation exposure and image noise of DVT is similar to low-dose CT, this imaging technique cannot be recommended as a general alternative to replace PR in dental radiology.

  20. Comparison between CT-based volumetric calculations and ICRU reference-point estimates of radiation doses delivered to bladder and rectum during intracavitary radiotherapy for cervical cancer.

    PubMed

    Pelloski, Christopher E; Palmer, Matthew; Chronowski, Gregory M; Jhingran, Anuja; Horton, John; Eifel, Patricia J

    2005-05-01

    To compare CT-based volumetric calculations and International Commission on Radiation Units and Measurements (ICRU) reference-point estimates of radiation doses to the bladder and rectum in patients with carcinoma of the uterine cervix treated with definitive low-dose-rate intracavitary radiotherapy (ICRT). Between November 2001 and March 2003, 60 patients were prospectively enrolled in a pilot study of ICRT with CT-based dosimetry. Most patients underwent two ICRT insertions. After insertion of an afterloading ICRT applicator, intraoperative orthogonal films were obtained to ensure proper positioning of the system and to facilitate subsequent planning. Treatments were prescribed using standard two-dimensional dosimetry and planning. Patients also underwent helical CT of the pelvis for three-dimensional reconstruction of the radiation dose distributions. The systems were loaded with 137Cs sources using the Selectron remote afterloading system according to institutional practice for low-dose-rate brachytherapy. Three-dimensional dose distributions were generated using the Varian BrachyVision treatment planning system. The rectum was contoured from the bottom of the ischial tuberosities to the sigmoid flexure. The entire bladder was contoured. The minimal doses delivered to the 2 cm3 of bladder and rectum receiving the highest dose (DBV2 and DRV2, respectively) were determined from dose-volume histograms, and these estimates were compared with two-dimensionally derived estimates of the doses to the corresponding ICRU reference points. A total of 118 unique intracavitary insertions were performed, and 93 were evaluated and the subject of this analysis. For the rectum, the estimated doses to the ICRU reference point did not differ significantly from the DRV2 (p = 0.561); the mean (+/- standard deviation) difference was 21 cGy (+/- 344 cGy). The median volume of the rectum that received at least the ICRU reference-point dose was 2.1 cm3. In 66 (71%) of 93 cases, <5 cm3

  1. Comparison between CT-based volumetric calculations and ICRU reference-point estimates of radiation doses delivered to bladder and rectum during intracavitary radiotherapy for cervical cancer

    SciTech Connect

    Pelloski, Christopher E.; Palmer, Matthew B.S.; Chronowski, Gregory M.; Jhingran, Anuja; Horton, John; Eifel, Patricia J. . E-mail: peifel@mdanderson.org

    2005-05-01

    Purpose: To compare CT-based volumetric calculations and International Commission on Radiation Units and Measurements (ICRU) reference-point estimates of radiation doses to the bladder and rectum in patients with carcinoma of the uterine cervix treated with definitive low-dose-rate intracavitary radiotherapy (ICRT). Methods and Materials: Between November 2001 and March 2003, 60 patients were prospectively enrolled in a pilot study of ICRT with CT-based dosimetry. Most patients underwent two ICRT insertions. After insertion of an afterloading ICRT applicator, intraoperative orthogonal films were obtained to ensure proper positioning of the system and to facilitate subsequent planning. Treatments were prescribed using standard two-dimensional dosimetry and planning. Patients also underwent helical CT of the pelvis for three-dimensional reconstruction of the radiation dose distributions. The systems were loaded with {sup 137}Cs sources using the Selectron remote afterloading system according to institutional practice for low-dose-rate brachytherapy. Three-dimensional dose distributions were generated using the Varian BrachyVision treatment planning system. The rectum was contoured from the bottom of the ischial tuberosities to the sigmoid flexure. The entire bladder was contoured. The minimal doses delivered to the 2 cm{sup 3} of bladder and rectum receiving the highest dose (D{sub BV2} and D{sub RV2}, respectively) were determined from dose-volume histograms, and these estimates were compared with two-dimensionally derived estimates of the doses to the corresponding ICRU reference points. Results: A total of 118 unique intracavitary insertions were performed, and 93 were evaluated and the subject of this analysis. For the rectum, the estimated doses to the ICRU reference point did not differ significantly from the D{sub RV2} (p = 0.561); the mean ({+-} standard deviation) difference was 21 cGy ({+-} 344 cGy). The median volume of the rectum that received at least

  2. Radiation: Doses, Effects, Risks.

    ERIC Educational Resources Information Center

    Lean, Geoffrey, Ed.

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

  3. Developing population estimates for dose reconstruction projects

    SciTech Connect

    Beck, D.M. )

    1991-01-01

    The Hanford Environmental Dose Reconstruction (HEDR) Project was established in 1987 to estimate radiation doses that people received from nuclear operations at the Hanford site since 1944. To achieve this objective, demographic information was developed that describes the study population in enough detail to allow researchers to identify potentially exposed groups and the number of people in each of those groups. This type of information is central to most dose reconstruction projects. The purpose of this paper is to detail how historical population estimates can be reconstructed in a reliable manner by comparing results using three different estimation methods.

  4. Estimates of radiation absorbed dose for intraperitoneally administered iodine-131 radiolabeled B72. 3 monoclonal antibody in patients with peritoneal carcinomatoses

    SciTech Connect

    Larson, S.M.; Carrasquillo, J.A.; Colcher, D.C.; Yokoyama, K.; Reynolds, J.C.; Bacharach, S.A.; Raubitchek, A.; Pace, L.; Finn, R.D.; Rotman, M. )

    1991-09-01

    Using a newly available model for determining estimates of radiation absorbed dose of radioisotopes administered intraperitoneally, the authors have calculated absorbed dose to tumor and normal tissues based on a surgically controlled study of radiolabeled antibody distribution. Ten patients with peritoneal carcinomatosis received intraperitoneal injections of the murine monoclonal antibody B72.3 radiolabeled with 131I. Biodistribution studies were performed using nuclear medicine methods until laparotomy at 4-14 days after injection. Surgical biopsies of normal tissues and tumor were obtained. The marrow was predicted to be the critical organ, with maximum tolerated dose (200 rad (2 Gy) to marrow) expected at about 200 mCi (7.4 GBq). In patients with large intraperitoneal tumor deposits, the tumor itself is an important source tissue for radiation exposure to normal tissues. Local hot-spots for tumor-absorbed dose were observed, with maximum tumor-absorbed dose calculated at 11,000 rad (11 Gy) per 100 mCi (3.7 GBq) administered intraperitoneal; however, tumor rad dose varied considerably. This may pose serious problems for curative therapy, especially in patients with large tumor burdens.

  5. Compartmental modeling of and radiation dose estimates for {sup 186}Re NR-LU-10 monoclonal antibody

    SciTech Connect

    Stubbs, J.B.; Beaumier, P.L.; Breitz, H.B.

    1994-05-01

    A clinical data set developed using {sup 186}Re labeled NR-LU-10, a pancarcinoma monoclonal antibody utilized for radioimmunotherapy, has been reanalyzed by compartmental modeling techniques. The pharmacokinetics and dosimetry estimates, derived from standard exponential curve filling, have been reported previously. In this work, we describe an 18-compartment model that integrates all measured biological data into a comprehensive biokinetic model. The model was developed with the SAAM (Simulation Analysis and Modeling) software. Residence times were calculated by integrating model-predicted time activity curves in tumor and 10 organs or tissues. Activity excreted via the hepatobiliary route was assumed to follow the ICRP 30 GI tract model, and a dynamic urinary bladder model (void interval = 4.8 hr) was used to simulate excretion via the urinary pathway. Dose estimates for 24 organs were calculated using the MIRD formalism. Tumor doses were estimated using absorbed fractions for electron sources uniformly distributed in small spheres. The model predicts that most activity is excreted (70% urine, 27% feces) by 300 hours post injection with the highest absorbed dose received by the excretory organs: lower large intestine (2.6 mGy/MBq), kidneys (1.4 mGy/MBq), upper large intestine (1.1 mGy/MBq). Tumor doses ranged from 180-1.8 mGy/MBq, depending on size (assuming tumor masses ranging from 1-100 grams). This multicompartmental model is comprehensive, provides conservation of activity, enables the modeling of hypothetical conditions (e.g., effect of plasma immunopheresis), and permits insight into the biological system.

  6. Estimated Radiation Dosage on Mars

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This global map of Mars shows the estimated radiation dosages from cosmic rays reaching the surface, a serious health concern for any future human exploration of the planet.

    The estimates are based on cosmic-radiation measurements by the Mars radiation environment experiment, an instrument on NASA's Mars 2000 Odyssey spacecraft, plus information about Mars' surface elevations from the laser altimeter instrument on NASA's Mars Global Surveyor. The areas of Mars expected to have the lowest levels of cosmic radiation are where the elevation is lowest, because those areas have more atmosphere above them to block out some of the radiation. Earth's thick atmosphere shields us from most cosmic radiation, but Mars has a much thinner atmosphere than we have on Earth.

    The colors in the map refer to the estimated annual dose equivalent in rems, a unit of radiation dose. The range is generally from 10 rems(color-coded dark blue) to 20 rems (color coded dark red). Radiation exposure for astronauts on the International Space Station in Earth orbit is typically equivalent to an annualized rate of 20 to 40 rems.

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

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

    PubMed

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

    2011-02-16

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

  8. THYROID CANCER STUDY AMONG UKRAINIAN CHILDREN EXPOSED TO RADIATION AFTER THE CHORNOBYL ACCIDENT: IMPROVED ESTIMATES OF THE THYROID DOSES TO THE COHORT MEMBERS

    PubMed Central

    Likhtarov, Ilya; Kovgan, Lina; Masiuk, Sergii; Talerko, Mykola; Chepurny, Mykola; Ivanova, Olga; Gerasymenko, Valentina; Boyko, Zulfira; Voillequé, Paul; Drozdovitch, Vladimir; Bouville, André

    2013-01-01

    In collaboration with the Ukrainian Research Center for Radiation Medicine, the U.S. National Cancer Institute initiated a cohort study of children and adolescents exposed to Chornobyl fallout in Ukraine to better understand the long-term health effects of exposure to radioactive iodines. All 13,204 cohort members were subjected to at least one direct thyroid measurement between 30 April and 30 June 1986 and resided at the time of the accident in the northern part of Kyiv, Zhytomyr, or Chernihiv Oblasts, which were the most contaminated territories of Ukraine as a result of radioactive fallout from the Chornobyl accident. Thyroid doses for the cohort members, which had been estimated following the first round of interviews, were re-evaluated following the second round of interviews. The revised thyroid doses range from 0.35 mGy to 42 Gy, with 95 percent of the doses between 1 mGy and 4.2 Gy, an arithmetic mean of 0.65 Gy, and a geometric mean of 0.19 Gy. These means are 70% of the previous estimates, mainly because of the use of country-specific thyroid masses. Many of the individual thyroid dose estimates show substantial differences because of the use of an improved questionnaire for the second round of interviews. Limitations of the current set of thyroid dose estimates are discussed. For the epidemiologic study, the most notable improvement is a revised assessment of the uncertainties, as shared and unshared uncertainties in the parameter values were considered in the calculation of the 1,000 stochastic estimates of thyroid dose for each cohort member. This procedure makes it possible to perform a more realistic risk analysis. PMID:25208014

  9. Estimation of annual effective dose and radiation hazards due to natural radionuclides in Mount Homa, southwestern Kenya.

    PubMed

    Otwoma, D; Patel, J P; Bartilol, S; Mustapha, A O

    2013-08-01

    The radiological hazard of naturally occurring radioactive material in Mount Homa in southwestern Kenya was investigated after 210 point measurements and 44 samples were analysed. In situ measured average outdoor absorbed dose rate in air using survey meters was found to vary from 154.8 to 2280.6 nGy h(-1). The mean (range) values of radioactive concentrations measured using an HpGe detection system for (40)K, (226)Ra and (232)Th were 915 ± 3 (64-3017), 195 ± 8 (17-1447) and 409 ± 4 (23-1369) Bq kg(-1), respectively. The calculated range of the annual effective dose for a person living in Homa Mountain area varied from 28.6 to 1681.2, with a mean of 470.4 µSv. All calculated average radiological indices, namely Radium equivalent, Representative level, Gamma activity, External and Internal hazard, were higher than the limits set by various national and international bodies. These results imply that Mount Homa region is a high background radiation area.

  10. Biodosimetry and assessment of radiation dose

    PubMed Central

    Crespo, Rafael Herranz; Domene, Mercedes Moreno; Rodríguez, María Jesús Prieto

    2011-01-01

    Aim When investigating radiation accidents, it is very important to determine the exposition dose to the individuals. In the case of exposures over 1 Gy, clinicians may expect deterministic effects arising the following weeks and months, in these cases dose estimation will help physicians in the planning of therapy. Nevertheless, for doses below 1 Gy, biodosimetry data are important due to the risk of developing late stochastic effects. Finally, some accidental overexposures are lack of physical measurements and the only way of quantifying dose is by biological dosimetry. Background The analysis of chromosomal aberrations by different techniques is the most developed method of quantifying dose to individuals exposed to ionising radiations.1,2 Furthermore, the analysis of dicentric chromosomes observed in metaphases from peripheral lymphocytes is the routine technique used in case of acute exposures to assess radiation doses. Materials and methods Solid stain of chromosomes is used to determine dicentric yields for dose estimation. Fluorescence in situ hybridization (FISH) for translocations analysis is used when delayed sampling or suspected chronically irradiation dose assessment. Recommendations in technical considerations are based mainly in the IAEA Technical Report No. 405.2 Results Experience in biological dosimetry at Gregorio Marañón General Hospital is described, including own calibration curves used for dose estimation, background studies and real cases of overexposition. Conclusion Dose assessment by biological dosimeters requires a large previous standardization work and a continuous update. Individual dose assessment involves high qualification professionals and its long time consuming, therefore requires specific Centres. For large mass casualties cooperation among specialized Institutions is needed. PMID:24376970

  11. Mapping of cosmic radiation dose in Croatia.

    PubMed

    Poje, M; Vuković, B; Radolić, V; Miklavčić, I; Faj, D; Varga Pajtler, M; Planinić, J

    2012-01-01

    The Earth is continually bombarded by high-energy particles coming from the outer space and the sun. These particles, termed cosmic radiation, interact with nuclei of atmospheric constituents and decrease in intensity with depth in the atmosphere. Measurements of photon and gamma radiation, performed with a Radiameter at 1 m above the ground, indicated dose rates of 50-100 nSv/h. The neutron dose rate was measured with the CR-39 track etch detector calibrated by the CERN-EU high-energy Reference Field (CERF) facility. Correlation between neutron dose rates and altitudes at 36 sites was examined in order to obtain a significant positive correlation coefficient; the resulting linear regression enabled estimation of a neutron dose at particular altitude. The measured neutron dose rate in Osijek (altitude of 89 m, latitude of 45.31° N) was 110 nSv/h. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Estimates of the image quality and the radiation dose for head and abdomen phantom image acquisition by using dual-energy CT

    NASA Astrophysics Data System (ADS)

    Kim, Dae-Hong; Kim, Hee-Joung; Lee, Chang-Lae; Jeon, Pil-Hyun; Lee, Won-Hyung; Jeon, Sung-Soo

    2012-04-01

    Using dual-energy computed tomography (CT) scans, we obtained images from a raw data set by using low- and high-energy scans (usually 80 and 140 kV, respectively). Generally, the head and the abdomen examinations were performed using single-energy (120 kV) scanning with a routine exposure protocol, and the images were used for diagnostic interpretation. The dual-energy CT scans can also be used for diagnosis by using the linearly-mixed method with low- and high-energy images. In the current study, we evaluated mixed images in dual-energy and single-energy scans for image quality and radiation dose. The CT scan protocol for single energy was adopted from IEC protocols, and the recommended dose from the EC. The dual-energy scan protocol was based on the Siemens dual-energy CT scan protocol. The CT scan protocols were extended further in the mA range for both scans to estimate the image quality corresponding to these dose alternations. The results demonstrate that the Contrast-to-noise ratio (CNR) value of a dual-energy mixed image is higher than that of a single-energy image in similar dose regions for both the head and the abdomen phantoms. We observed that the dual-energy images could reduce the dose compared to single-energy images. In the abdomen phantom study, the CNR of dual-energy images was even higher than that of single-energy images with half the radiation dose of the single-energy scan. Therefore, the dual-energy CT scan can accomplish a remarkable dose reduction while preserving image quality for head and abdomen imaging.

  13. Methods of calculating radiation absorbed dose.

    PubMed

    Wegst, A V

    1987-01-01

    The new tumoricidal radioactive agents being developed will require a careful estimate of radiation absorbed tumor and critical organ dose for each patient. Clinical methods will need to be developed using standard imaging or counting instruments to determine cumulated organ activities with tracer amounts before the therapeutic administration of the material. Standard MIRD dosimetry methods can then be applied.

  14. Atmospheric radiation flight dose rates

    NASA Astrophysics Data System (ADS)

    Tobiska, W. K.

    2015-12-01

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

  15. Prediction of the location and size of the stomach using patient characteristics for retrospective radiation dose estimation following radiotherapy

    NASA Astrophysics Data System (ADS)

    Lamart, Stephanie; Imran, Rebecca; Simon, Steven L.; Doi, Kazutaka; Morton, Lindsay M.; Curtis, Rochelle E.; Lee, Choonik; Drozdovitch, Vladimir; Maass-Moreno, Roberto; Chen, Clara C.; Whatley, Millie; Miller, Donald L.; Pacak, Karel; Lee, Choonsik

    2013-12-01

    Following cancer radiotherapy, reconstruction of doses to organs, other than the target organ, is of interest for retrospective health risk studies. Reliable estimation of doses to organs that may be partially within or fully outside the treatment field requires reliable knowledge of the location and size of the organs, e.g., the stomach, which is at risk from abdominal irradiation. The stomach location and size are known to be highly variable between individuals, but have been little studied. Moreover, for treatments conducted years ago, medical images of patients are usually not available in medical records to locate the stomach. In light of the poor information available to locate the stomach in historical dose reconstructions, the purpose of this work was to investigate the variability of stomach location and size among adult male patients and to develop prediction models for the stomach location and size using predictor variables generally available in medical records of radiotherapy patients treated in the past. To collect data on stomach size and position, we segmented the contours of the stomach and of the skeleton on contemporary computed tomography (CT) images for 30 male patients in supine position. The location and size of the stomach was found to depend on body mass index (BMI), ponderal index (PI), and age. For example, the anteroposterior dimension of the stomach was found to increase with increasing BMI (≈0.25 cm kg-1 m2) whereas its craniocaudal dimension decreased with increasing PI (≈-3.3 cm kg-1 m3) and its transverse dimension increased with increasing PI (≈2.5 cm kg-1 m3). Using the prediction models, we generated three-dimensional computational stomach models from a deformable hybrid phantom for three patients of different BMI. Based on a typical radiotherapy treatment, we simulated radiotherapy treatments on the predicted stomach models and on the CT images of the corresponding patients. Those dose calculations demonstrated good

  16. Prediction of the location and size of the stomach using patient characteristics for retrospective radiation dose estimation following radiotherapy

    PubMed Central

    Lamart, Stephanie; Imran, Rebecca; Simon, Steven L.; Doi, Kazutaka; Morton, Lindsay M.; Curtis, Rochelle E.; Lee, Choonik; Drozdovitch, Vladimir; Maass-Moreno, Roberto; Chen, Clara C.; Whatley, Millie; Miller, Donald L.; Pacak, Karel; Lee, Choonsik

    2014-01-01

    Following cancer radiotherapy, reconstruction of doses to organs, other than the target organ, is of interest for retrospective health risk studies. Reliable estimation of doses to organs that may be partially within or fully outside the treatment field requires reliable knowledge of the location and size of the organs, e.g., the stomach, which is at risk from abdominal irradiation. The stomach location and size are known to be highly variable between individuals, but have been little studied. Moreover, for treatments conducted years ago, medical images of patients are usually not available in medical records to locate the stomach. In light of the poor information available to locate the stomach in historical dose reconstructions, the purpose of this work was to investigate the variability of stomach location and size among adult male patients and to develop prediction models for the stomach location and size using predictor variables generally available in medical records of radiotherapy patients treated in the past. To collect data on stomach size and position, we segmented the contours of the stomach and of the skeleton on contemporary Computed Tomography (CT) images for 30 male patients in supine position. The location and size of the stomach was found to depend on body mass index (BMI), ponderal index (PI), and age. For example, the anteroposterior dimension of the stomach was found to increase with increasing BMI (≈0.25 cm per kg/m2) whereas its craniocaudal dimension decreased with increasing PI (≈ −3.3 cm per kg/m3) and its transverse dimension increased with increasing PI (≈ 2.5 cm per kg/m3). Using the prediction models, we generated three dimensional computational stomach models from a deformable hybrid phantom for three patients of different BMI. Based on a typical radiotherapy treatment, we simulated radiotherapy treatments on the predicted stomach models and on the CT images of the corresponding patients. Those dose calculations demonstrated

  17. Prediction of the location and size of the stomach using patient characteristics for retrospective radiation dose estimation following radiotherapy.

    PubMed

    Lamart, Stephanie; Imran, Rebecca; Simon, Steven L; Doi, Kazutaka; Morton, Lindsay M; Curtis, Rochelle E; Lee, Choonik; Drozdovitch, Vladimir; Maass-Moreno, Roberto; Chen, Clara C; Whatley, Millie; Miller, Donald L; Pacak, Karel; Lee, Choonsik

    2013-12-21

    Following cancer radiotherapy, reconstruction of doses to organs, other than the target organ, is of interest for retrospective health risk studies. Reliable estimation of doses to organs that may be partially within or fully outside the treatment field requires reliable knowledge of the location and size of the organs, e.g., the stomach, which is at risk from abdominal irradiation. The stomach location and size are known to be highly variable between individuals, but have been little studied. Moreover, for treatments conducted years ago, medical images of patients are usually not available in medical records to locate the stomach. In light of the poor information available to locate the stomach in historical dose reconstructions, the purpose of this work was to investigate the variability of stomach location and size among adult male patients and to develop prediction models for the stomach location and size using predictor variables generally available in medical records of radiotherapy patients treated in the past. To collect data on stomach size and position, we segmented the contours of the stomach and of the skeleton on contemporary computed tomography (CT) images for 30 male patients in supine position. The location and size of the stomach was found to depend on body mass index (BMI), ponderal index (PI), and age. For example, the anteroposterior dimension of the stomach was found to increase with increasing BMI (≈0.25 cm kg(-1) m(2)) whereas its craniocaudal dimension decreased with increasing PI (≈-3.3 cm kg(-1) m(3)) and its transverse dimension increased with increasing PI (≈2.5 cm kg(-1) m(3)). Using the prediction models, we generated three-dimensional computational stomach models from a deformable hybrid phantom for three patients of different BMI. Based on a typical radiotherapy treatment, we simulated radiotherapy treatments on the predicted stomach models and on the CT images of the corresponding patients. Those dose calculations demonstrated

  18. EXOMARS IRAS (DOSE) radiation measurements.

    NASA Astrophysics Data System (ADS)

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

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

  19. Dose estimates from the Chernobyl accident

    SciTech Connect

    Lange, R.; Dickerson, M.H.; Gudiksen, P.H.

    1987-11-01

    The Lawrence Livermore National Laboratory Atmospheric Release Advisory Capability (ARAC) responded to the Chernobyl nuclear reactor accident in the Soviet Union by utilizing long-range atmospheric dispersion modeling to estimate the amount of radioactivity released (source term) and the radiation dose distribution due to exposure to the radioactive cloud over Europe and the Northern Hemisphere. In later assessments, after the release of data on the accident by the Soviet Union, the ARAC team used their mesoscale to regional scale model to focus in on the radiation dose distribution within the Soviet Union and the vicinity of the Chernobyl plant. 22 refs., 5 figs., 5 tabs.

  20. Dose estimates from the Chernobyl accident

    SciTech Connect

    Lange, R.; Dickerson, M.H.; Gudiksen, P.H. )

    1988-09-01

    The Lawrence Livermore National Laboratory Atmospheric Release Advisory Capability (ARAC) responded to the Chernobyl nuclear reactor accident in the Soviet Union by utilizing long-range atmospheric dispersion modeling to estimate the amount of radioactivity released (source term) and the radiation dose distribution due to exposure to the radioactive cloud over Europe and the northern hemisphere. In later assessments, after the release of data on the accident by the Soviet Union, the ARAC team used their mesoscale-to-regional-scale model to focus on the radiation dose distribution within the Soviet Union and the vicinity of the Chernobyl plant.

  1. Dose Estimation in Pediatric Nuclear Medicine.

    PubMed

    Fahey, Frederic H; Goodkind, Alison B; Plyku, Donika; Khamwan, Kitiwat; O'Reilly, Shannon E; Cao, Xinhua; Frey, Eric C; Li, Ye; Bolch, Wesley E; Sgouros, George; Treves, S Ted

    2017-03-01

    The practice of nuclear medicine in children is well established for imaging practically all physiologic systems but particularly in the fields of oncology, neurology, urology, and orthopedics. Pediatric nuclear medicine yields images of physiologic and molecular processes that can provide essential diagnostic information to the clinician. However, nuclear medicine involves the administration of radiopharmaceuticals that expose the patient to ionizing radiation and children are thought to be at a higher risk for adverse effects from radiation exposure than adults. Therefore it may be considered prudent to take extra care to optimize the radiation dose associated with pediatric nuclear medicine. This requires a solid understanding of the dosimetry associated with the administration of radiopharmaceuticals in children. Models for estimating the internal radiation dose from radiopharmaceuticals have been developed by the Medical Internal Radiation Dosimetry Committee of the Society of Nuclear Medicine and Molecular Imaging and other groups. But to use these models accurately in children, better pharmacokinetic data for the radiopharmaceuticals and anatomical models specifically for children need to be developed. The use of CT in the context of hybrid imaging has also increased significantly in the past 15 years, and thus CT dosimetry as it applies to children needs to be better understood. The concept of effective dose has been used to compare different practices involving radiation on a dosimetric level, but this approach may not be appropriate when applied to a population of children of different ages as the radiosensitivity weights utilized in the calculation of effective dose are not specific to children and may vary as a function of age on an organ-by-organ bias. As these gaps in knowledge of dosimetry and radiation risk as they apply to children are filled, more accurate models can be developed that allow for better approaches to dose optimization. In turn, this

  2. Doses from Medical Radiation Sources

    MedlinePlus

    ... that the best approach is to make individual measurements of breast milk activity and individual-specific projections ... 70:437–439; 1997. (5,000 patient dose measurements from 375 hospitals) International Commission on Radiation Protection. ...

  3. The Dose Response Relationship for Radiation Carcinogenesis

    NASA Astrophysics Data System (ADS)

    Hall, Eric

    2008-03-01

    Recent surveys show that the collective population radiation dose from medical procedures in the U.S. has increased by 750% in the past two decades. It would be impossible to imagine the practice of medicine today without diagnostic and therapeutic radiology, but nevertheless the widespread and rapidly increasing use of a modality which is a known human carcinogen is a cause for concern. To assess the magnitude of the problem it is necessary to establish the shape of the dose response relationship for radiation carcinogenesis. Information on radiation carcinogenesis comes from the A-bomb survivors, from occupationally exposed individuals and from radiotherapy patients. The A-bomb survivor data indicates a linear relationship between dose and the risk of solid cancers up to a dose of about 2.5 Sv. The lowest dose at which there is a significant excess cancer risk is debatable, but it would appear to be between 40 and 100 mSv. Data from the occupation exposure of nuclear workers shows an excess cancer risk at an average dose of 19.4 mSv. At the other end of the dose scale, data on second cancers in radiotherapy patients indicates that cancer risk does not continue to rise as a linear function of dose, but tends towards a plateau of 40 to 60 Gy, delivered in a fractionated regime. These data can be used to estimate the impact of diagnostic radiology at the low dose end of the dose response relationship, and the impact of new radiotherapy modalities at the high end of the dose response relationship. In the case of diagnostic radiology about 90% of the collective population dose comes from procedures (principally CT scans) which involve doses at which there is credible evidence of an excess cancer incidence. While the risk to the individual is small and justified in a symptomatic patient, the same is not true of some screening procedures is asymptomatic individuals, and in any case the huge number of procedures must add up to a potential public health problem. In the

  4. Global quantification of γH2AX as a triage tool for the rapid estimation of received dose in the event of accidental radiation exposure.

    PubMed

    Viau, Muriel; Testard, Isabelle; Shim, Grace; Morat, Luc; Normil, Marie D; Hempel, William M; Sabatier, Laure

    2015-11-01

    The phosphorylation of the H2AX histone to form γH2AX foci has been shown to be an accurate biomarker of ionizing radiation exposure. It is well established that there is a one-to-one correlation between the number of γH2AX foci and radiation-induced double strand breaks in cellular DNA, which can be translated to the received dose. However, manual counting of foci is time-consuming, and cannot accommodate high throughput analysis required to obtain rapid results for medical triage purposes in the case of large-scale accidental exposure. Furthermore, the accuracy of γH2AX measurements could potentially be compromised by delays between the time of exposure and analysis of results, as well as inter-cellular and inter-individual variability of this biological response. To evaluate more rapid approaches of quantifying γH2AX for use in an emergency situation, and to determine the impact of inter-individual variability, we compared two methods of global γH2AX fluorescence quantification (low magnification immunofluorescence microscopy and flow cytometry) to the well-established γH2AX foci scoring method in human primary fibroblasts. All three approaches were well correlated, indicating that global γH2AX fluorescence measurements are suitable for dose estimation. For rapid triage in an emergency situation, we propose the use of flow cytometry, as it is more highly correlated with foci scoring and because of the speed and ease of the method. Dose response curves (0.25-6Gy) using flow cytometry measurements showed that inter-individual variability in global γH2AX fluorescence is statistically insignificant at 4h post-irradiation. Based on these data, we propose calibration curves that can be applied to populations exposed to moderate radiation doses to estimate individual received doses, independent of individual radiosensitivity, at this specific time point post-irradiation using human fibroblasts and lymphocytes. Furthermore, we define three triage categories that

  5. Estimation of Errors Associated With Use of Linear-Quadratic Formalism for Evaluation of Biologic Equivalence Between Single and Hypofractionated Radiation Doses: An In Vitro Study

    SciTech Connect

    Iwata, Hiromitsu Shibamoto, Yuta; Murata, Rumi; Tomita, Natsuo; Ayakawa, Shiho; Ogino, Hiroyuki; Ito, Masato

    2009-10-01

    Purpose: To investigate the reliability of the linear-quadratic (LQ) formalism and the magnitude of errors associated with its use in assessing biologic equivalence between single, high radiation doses and hypofractionated radiation doses. Methods and Materials: V79 and EMT6 single cells received single doses of 2-12 Gy or two or three fractions of 4 or 5 Gy, each at 4-h intervals. Single and fractionated doses to actually reduce the cell survival to the same level were determined by a colony assay. The {alpha}/{beta} ratio was obtained from the cell survival curves. Using the {alpha}/{beta} ratio and the LQ formalism, equivalent single doses for the hypofractionated doses were calculated. They were then compared with the actually determined equivalent single doses for the hypofractionated doses. The V79 spheroids received single doses of 5-26 Gy or two to five fractions of 5-12 Gy at 2 or 4-h interval, and then were assayed for cell survival. Next, equivalent single doses for the hypofractionated doses were determined, as were done for the single cells. Results: The {alpha}/{beta} ratio was 5.1 Gy for the V79 single cells and 0.36 Gy for EMT6. In V79, the equivalent single doses for the hypofractionated doses calculated using the LQ formalism were 12-19% lower than the actually measured biologically equivalent single doses. In the EMT6 cells, this trend was also seen, but the differences were not significant. In the V79 spheroids, the calculated doses were 18-30% lower than the measured doses. Conclusion: Conversion of hypofractionated radiation doses to single doses using the LQ formalism could underestimate the effect of hypofractionated radiation by {<=}30%.

  6. Estimating 131I biokinetics and radiation doses to the red marrow and whole body in thyroid cancer patients: probe detection versus image quantification*

    PubMed Central

    Willegaignon, José; Pelissoni, Rogério Alexandre; Lima, Beatriz Christine de Godoy Diniz; Sapienza, Marcelo Tatit; Coura-Filho, George Barberio; Queiroz, Marcelo Araújo; Buchpiguel, Carlos Alberto

    2016-01-01

    Objective To compare the probe detection method with the image quantification method when estimating 131I biokinetics and radiation doses to the red marrow and whole body in the treatment of thyroid cancer patients. Materials and Methods Fourteen patients with metastatic thyroid cancer, without metastatic bone involvement, were submitted to therapy planning in order to tailor the therapeutic amount of 131I to each individual. Whole-body scans and probe measurements were performed at 4, 24, 48, 72, and 96 h after 131I administration in order to estimate the effective half-life (Teff) and residence time of 131I in the body. Results The mean values for Teff and residence time, respectively, were 19 ± 9 h and 28 ± 12 h for probe detection, compared with 20 ± 13 h and 29 ± 18 h for image quantification. The average dose to the red marrow and whole body, respectively, was 0.061 ± 0.041 mGy/MBq and 0.073 ± 0.040 mGy/MBq for probe detection, compared with 0.066 ± 0.055 mGy/MBq and 0.078 ± 0.056 mGy/MBq for image quantification. Statistical analysis proved that there were no significant differences between the two methods for estimating the Teff (p = 0.801), residence time (p = 0.801), dose to the red marrow (p = 0.708), and dose to the whole body (p = 0.811), even when we considered an optimized approach for calculating doses only at 4 h and 96 h after 131I administration (p > 0.914). Conclusion There is full agreement as to the feasibility of using probe detection and image quantification when estimating 131I biokinetics and red-marrow/whole-body doses. However, because the probe detection method is inefficacious in identifying tumor sites and critical organs during radionuclide therapy and therefore liable to skew adjustment of the amount of 131I to be administered to patients under such therapy, it should be used with caution. PMID:27403014

  7. Measurement of potential alpha energy exposure and potential alpha energy concentration and estimating radiation dose of radon in Sari city in the north region of Iran.

    PubMed

    Rahimi, Seyed Ali; Nikpour, Behzad

    2014-12-01

    In dwellings in Sari city in the northern region of Iran, the potential alpha energy exposure (PAEE) and potential alpha energy concentration (PAEC) have been measured and the radiation dose due to radon and its progenies has been estimated. In this study, the dosemeters DOSEman and SARAD GmbH (Germany), which are sensitive to alpha particles, were used. The population of the city of Sari is 495,369 people and the density of population is 116.5 people per km(2). A percentage of the total household population of Sari in areas of geographically different samples was selected. The PAEE, PAEC and radon concentration in four different seasons in a year in homes for sampling were measured. The mean PAEE due to indoor radon in homes of four cities in Sari city was estimated to be 28.23 Bq m(-3) and the mean PAEC was estimated to be 27.11 Bq m(-3). Also the mean indoor radon level was found to be 29.95 Bq m(-3). The annual dose equivalent is ∼0.0151 μSv y(-1). Measurement results show that the average PAEE, PAEC and radon concentration are higher in winter than in other seasons. This difference could be due to stillness and lack of air movement indoors in winter.

  8. Estimation of the fluence of high-energy electron bursts produced by thunderclouds and the resulting radiation doses received in aircraft

    NASA Astrophysics Data System (ADS)

    Dwyer, J. R.; Smith, D. M.; Uman, M. A.; Saleh, Z.; Grefenstette, B.; Hazelton, B.; Rassoul, H. K.

    2010-05-01

    Using recent X-ray and gamma-ray observations of terrestrial gamma-ray flashes (TGFs) from spacecraft and of natural and rocket-triggered lightning from the ground, along with detailed models of energetic particle transport, we calculate the fluence (integrated flux) of high-energy (million electronvolt) electrons, X rays, and gamma rays likely to be produced inside or near thunderclouds in high electric field regions. We find that the X-ray/gamma-ray fluence predicted for lightning leaders propagating inside thunderclouds agrees well with the fluence calculated for TGFs, suggesting a possible link between these two phenomena. Furthermore, based on reasonable meteorological assumptions about the magnitude and extent of the electric fields, we estimate that the fluence of high-energy runaway electrons can reach biologically significant levels at aircraft altitudes. If an aircraft happened to be in or near the high-field region when either a lightning discharge or a TGF event is occurring, then the radiation dose received by passengers and crew members inside that aircraft could potentially approach 0.1 Sv (10 rem) in less than 1 ms. Considering that commercial aircraft are struck by lightning, on average, one to two times per year, the risk of such large radiation doses should be investigated further.

  9. Radiation dose response estimation with emphasis on low dose range using restricted cubic splines: application to all solid cancer mortality data, 1950-2003, in atomic bomb survivors.

    PubMed

    Nakashima, Eiji

    2015-07-01

    Using the all solid cancer mortality data set of the Life Span Study (LSS) cohort from 1950 to 2003 (LSS Report 14) data among atomic bomb survivors, excess relative risk (ERR) statistical analyses were performed using the second degree polynomial and the threshold and restricted cubic spline (RCS) dose response models. For the RCS models with 3 to 7 knots of equally spaced percentiles with margins in the dose range greater than 50 mGy, the dose response was assumed to be linear at less than 70 to 90 mGy. Due to the skewed dose distribution of atomic bomb survivors, the current knot system for the RCS analysis results in a detailed depiction of the dose response as less than approximately 0.5 Gy. The 6 knot RCS models for the all-solid cancer mortality dose response of the whole dose or less than 2 Gy were selected with the AIC model selection criterion and fit significantly better (p < 0.05) than the linear (L) model. The usual RCS includes the L-global model but not the quadratic (Q) nor linear-quadratic (LQ) global models. The authors extended the RCS to include L or LQ global models by putting L or LQ constraints on the cubic spline in the lower and upper tails, and the best RCS model selected with AIC criterion was the usual RCS with L-constraints in both the lower and upper tails. The selected RCS had a linear dose-response model in the lower dose range (i.e., < 0.2-0.3 Gy) and was compatible with the linear no-threshold (LNT) model in this dose range. The proposed method is also useful in describing the dose response of a specific cancer or non-cancer disease incidence/mortality.

  10. Estimation and comparison of the radiation effective dose during coronary computed tomography angiography examinations on single-source 64-MDCT and dual-source 128-MDCT.

    PubMed

    Khoramian, Daryoush; Sistani, Soroush

    2017-09-14

    To estimate and compare the radiation dose associated with coronary computed tomography angiography (CCTA) examinations on two multi-detector CT scanners (MDCT), 64-MDCT and 128-MDCT, in daily practice. Scan parameters of 90 patients undergoing retrospective electrocardiographic gating spiral CCTA exam were recorded during a period on a single-source 64-MDCT and a dual-source 128-MDCT, and average scan parameters were derived that were used for dosimetry. The computed tomography dose index (CTDI) with a pencil ionisation chamber and polymethyl methacrylate body phantom with diameter of 32 cm was measured on both scanners. The dose-length product (DLP) was calculated and the DLP to effective dose conversion factor (for chest scan at 120 kV of 0.014 mSv mGy(-1) cm(-1)) was used to estimate effective dose (ED). Patients' heart rate, scan length, pitch factor, CTDIv, DLP and ED for 128-MDCT were 64 (5) (beats min(-1)), 161 (10) (mm), 0.26, 47 (12) (mGy), 769 (212) (mGy cm) and 10.3 (3.1) (mSv), respectively [mean (one standard deviation)]. Patients' heart rate, scan length, pitch factor, CTDIv, DLP and ED for 64-MDCT were 60 (7) (beats min(-1)), 172 (14) (mm), 0.2, 60 (6) (mGy), 1068 (98) (mGy cm) and 14.9 (1.4) (mSv), respectively. Our results indicated that the CTDIv, DLP and the effective dose with 128-MDCT is significantly lower than with 64-MDCT (p < 0.05). As differences between the exposure parameter mAs on two CT scanners was not significant (p > 0.05) and the kV was constant for both scanners (120 kV), the differences resulted from a shorter scan length on the 128-MDCT and use of a higher pitch factor (0.26 and 0.2 in the 128-MDCT and 64-MDCT, respectively). Comparison with other published studies confirms the findings and indicates methods for reducing patient dose.

  11. Pediatric CT: Strategies to Lower Radiation Dose

    PubMed Central

    Zacharias, Claudia; Alessio, Adam M.; Otto, Randolph K.; Iyer, Ramesh S.; Philips, Grace S.; Swanson, Jonathan O.; Thapa, Mahesh M.

    2016-01-01

    OBJECTIVE The introduction of MDCT has increased the utilization of CT in pediatric radiology along with concerns for radiation sequelae. This article reviews general principles of lowering radiation dose, the basic physics that impact radiation dose, and specific CT integrated dose-reduction tools focused on the pediatric population. CONCLUSION The goal of this article is to provide a comprehensive review of the recent literature regarding CT dose reduction methods, their limitations, and an outlook on future developments with a focus on the pediatric population. The discussion will initially focus on general considerations that lead to radiation dose reduction, followed by specific technical features that influence the radiation dose. PMID:23617474

  12. Agriculture-related radiation dose calculations

    SciTech Connect

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

    1987-10-01

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

  13. Incidence of malignant thyroid tumors in humans after exposure to diagnostic doses of /sup 131/I. II. Estimation of thyroid gland size, thyroid radiation dose, and predicted versus observed number of malignant thyroid tumors

    SciTech Connect

    Holm, L.E.; Eklund, G.; Lundell, G.

    1980-12-01

    The size of the thyroid glands was analyzed for 10% of the patients in a selected group that had been exposed to diagnostic doses of /sup 131/I. The mean thyroid gland weight +- SD was 50 +- 33 g for patients 20 or more years of age and 10 +- 5 g for patients less than 20 years of age. With the present follow-up, diagnostic doses of /sup 131/I appeared not to be associated with an increased risk for later development of malignant thyroid tumors. Possible reasons for the difference between the observed number of such tumors and the number expected (47 to 124) on the basis of risk estimates of the United Nations Scientific Committee on the Effects of Atomic Radiation are discussed.

  14. Implications of the Hiroshima-Nagasaki genetic studies for the estimation of the human "doubling dose" of radiation.

    PubMed

    Neel, J V; Schull, W J; Awa, A A; Satoh, C; Otake, M; Kato, H; Yoshimoto, Y

    1989-01-01

    Since 1946 a continuous effort to evaluate the potential genetic effects of the atomic bombs has been sustained. Observations on children born in Hiroshima and Nagasaki include sex ratio, congenital malformations, stillbirths, survival of liveborn infants, chromosomal abnormalities (sex chromosomal abnormalities and balanced chromosomal rearrangements), mutations altering protein structure or activity, and physical growth and development. There are no statistically significant differences between the children of parents who received increased amounts of radiation at the time of the bombings and those whose parents did not. However, the difference between the two sets of children is consistent with the hypothesis of a genetic effect of the exposure, but its magnitude suggests humans are not as sensitive to the genetic effects of radiation as projected from the mouse paradigm.

  15. Low-dose radiation epidemiology studies: status and issues.

    PubMed

    Shore, Roy E

    2009-11-01

    Although the Japanese atomic bomb study and radiotherapy studies have clearly documented cancer risks from high-dose radiation exposures, radiation risk assessment groups have long recognized that protracted or low exposures to low-linear energy transfer radiations are key radiation protection concerns because these are far more common than high-exposure scenarios. Epidemiologic studies of human populations with low-dose or low dose-rate exposures are one approach to addressing those concerns. A number of large studies of radiation workers (Chernobyl clean-up workers, U.S. and Chinese radiological technologists, and the 15-country worker study) or of persons exposed to environmental radiation at moderate to low levels (residents near Techa River, Semipalatinsk, Chernobyl, or nuclear facilities) have been conducted. A variety of studies of medical radiation exposures (multiple-fluoroscopy, diagnostic (131)I, scatter radiation doses from radiotherapy, etc.) also are of interest. Key results from these studies are summarized and compared with risk estimates from the Japanese atomic bomb study. Ideally, one would like the low-dose and low dose-rate studies to guide radiation risk estimation regarding the shape of the dose-response curve, DDREF (dose and dose-rate effectiveness factor), and risk at low doses. However, the degree to which low-dose studies can do so is subject to various limitations, especially those pertaining to dosimetric uncertainties and limited statistical power. The identification of individuals who are particularly susceptible to radiation cancer induction also is of high interest in terms of occupational and medical radiation protection. Several examples of studies of radiation-related cancer susceptibility are discussed, but none thus far have clearly identified radiation-susceptible genotypes.

  16. Radiation Dose from Reentrant Electrons

    NASA Technical Reports Server (NTRS)

    Badhwar, G.D.; Cleghorn, T. E.; Watts, J.

    2003-01-01

    In estimating the crew exposures during an EVA, the contribution of reentrant electrons has always been neglected. Although the flux of these electrons is small compared to the flux of trapped electrons, their energy spectrum extends to several GeV compared to about 7 MeV for trapped electrons. This is also true of splash electrons. Using the measured reentrant electron energy spectra, it is shown that the dose contribution of these electrons to the blood forming organs (BFO) is more than 10 times greater than that from the trapped electrons. The calculations also show that the dose-depth response is a very slowly changing function of depth, and thus adding reasonable amounts of additional shielding would not significantly lower the dose to BFO.

  17. Estimation of Radiation Doses in the Marshall Islands Based on Whole Body Counting of Cesium-137 (137Cs) and Plutonium Urinalysis

    SciTech Connect

    Daniels, J; Hickman, D; Kehl, S; Hamilton, T

    2007-06-11

    measurement. The amount of {sup 137}Cs detected is often reported in activity units of kilo-Becquerel (kBq), where 1 kBq equals 1000 Bq and 1 Bq = 1 nuclear transformation per second (t s{sup -1}). [However, in the United States the Curie (Ci) continues to be used as the unit of radioactivity; where 1 Ci = 3.7 x 10{sup 10} Bq.] The detection of {sup 239}Pu and {sup 240}Pu in bioassay (urine) samples indicates the presence of internally deposited (systemic) plutonium in the body. Urine samples that are collected in the Marshall Islands from volunteers participating in the RSMP are transported to LLNL, where measurements for {sup 239+240}Pu are performed using a state-of-the-art technology based on Accelerator Mass Spectrometry (AMS) (Hamilton et al., 2004, 2007; Brown et al., 2004). The urinary excretion of plutonium by RSMP volunteers is usually described in activity units, expressed as micro-Becquerel ({micro}Bq) of {sup 239+240}Pu (i.e., representing the sum of the {sup 239}Pu and {sup 240}Pu activity) excreted (lost) per day (d{sup -1}), where 1 {micro}Bq d{sup -1} = 10{sup -6} Bq d{sup -1} and 1 Bq = 1 t s{sup -1}. The systemic burden of plutonium is then estimated from biokinetic relationships as described by the International Commission on Radiological Protection (e.g., see ICRP, 1990). In general, nuclear transformations are accompanied by the emission of energy and/or particles in the form of gamma rays ({gamma}), beta particles ({beta}), and/or alpha particles ({alpha}). Tissues in the human body may adsorb these emissions, where there is a potential for any deposited energy to cause biological damage. The general term used to quantify the extent of any radiation exposure is referred to as the dose. The equivalent dose is defined by the average absorbed dose in an organ or tissue weighted by the average quality factor for the type and energy of the emission causing the dose. The effective dose equivalent (EDE; as applied to the whole body), is the sum of the average

  18. Effects of low doses of radiation.

    PubMed

    Fry, R J

    1996-06-01

    This is a brief review of what is known from experimental studies about the effects of low doses of radiation, and approaches that might improve risk estimates are discussed. The dose-response relationships for cancer induction by radiation vary markedly between tissues. The evidence suggests that 1) the induction of the initial events is dependent on the cell type because the size and/or the number of targets and how the cells handle the initial lesions differs between cell types; and 2) there are marked differences among tissues how initial lesions are expressed and proceed to overt cancer. The recent findings about adaptive responses are discussed in the context of what they contribute to our understanding about the response to irradiation. Lastly, the possibility of extending the approach of determining "The probability of causation," which Vic Bond played such an important role in establishing, is raised.

  19. [About Dose-Effect Relationship in the Environment Radiation Protection].

    PubMed

    Udalova, A A

    2015-01-01

    One of the most important stages in the development of a methodology for the environment radiation protection is the assessment and justification of critical radiation exposure levels for ecosystem components. In this study application of the approach for critical dose level estimation is demonstrated on the example of the data about ionizing radiation effect on reproduction and survival of agricultural plants after acute and chronic exposures. Influence of the type of dose-effect relationship on the estimated values of the critical doses and dose rates is studied using three models (linear, logarithmic and logistic). The findings obtained do not provide any robust recommendations in favor of one of the three tested functions. The models of dose-effect relationship (threshold or non-threshold) and types of radiation-induced effects (stochastic and deterministic) are discussed from the viewpoint of developing a system for radiation protection of human and non-human biota.

  20. Radiation dose from cardiac computed tomography before and after implementation of radiation dose-reduction techniques.

    PubMed

    Raff, Gilbert L; Chinnaiyan, Kavitha M; Share, David A; Goraya, Tauqir Y; Kazerooni, Ella A; Moscucci, Mauro; Gentry, Ralph E; Abidov, Aiden

    2009-06-10

    Cardiac computed tomography angiography (CCTA) can accurately diagnose coronary artery disease, but radiation dose from this procedure is of concern. To determine whether a collaborative radiation dose-reduction program would be associated with reduced radiation dose in patients undergoing CCTA in a statewide registry over a 1-year period and to define its effect on image quality. A prospective, controlled, nonrandomized study conducted during a control period (July-August 2007), an intervention period (September 2007-April 2008), and a follow-up period (May-June 2008) at 15 hospital imaging centers participating in the Advanced Cardiovascular Imaging Consortium in Michigan, which included small community hospitals and large academic medical centers. A total of 4995 sequential patients undergoing CCTA for suspected coronary artery disease were enrolled; 4862 patients (97.3%) had complete radiation data for analysis. A best-practice CCTA scan model was used, which included minimized scan range, heart rate reduction, electrocardiographic-gated tube current modulation, and reduced tube voltage in suitable patients. Primary outcomes included dose-length product and effective radiation dose from all phases of the CCTA scan. Secondary outcomes were image quality assessed by a 4-point scale (1 indicated excellent; 2, good; 3, adequate; and 4, nondiagnostic) and frequency of diagnostic-quality scans. Compared with the control period, patients' estimated median radiation dose in the follow-up period was reduced by 53.3% (dose-length product decreased from 1493 mGy x cm [interquartile range {IQR}, 855-1823 mGy x cm] to 697 mGy x cm [IQR, 407-1163 mGy x cm]; P < .001) and effective dose from 21 mSv (IQR, 12-26 mSv) to 10 mSv (IQR, 6-16 mSv) (P < .001). The greatest reduction in dose occurred at low-volume sites. There were no significant changes in median image quality assessment during the control period compared with the follow-up period (median image quality of 2 [images

  1. Radiation dose in computed tomography of the chest.

    PubMed

    Tack, D; Gevenois, P A

    2004-01-01

    Since the beginning of the eighties, computed tomography (CT) has been more and more widely used as this technique provides precise anatomical details on the lungs, the mediastinum, and the chest wall. However, CT requires the use of ionizing radiations. The collective radiation from CT is therefore in constant increase. As evaluated on atomic bomb survivors, ionizing radiations increase the mortality by cancer. The risk is proportional to the dose and the dose related to CT is much higher than that related to a chest radiograph, both being in the field "of low-level radiations" a range of radiation dose from which no increase in cancer mortality could be demonstrated. This article outlines the risk estimation in the field of low-level radiations, the various methods to measure and estimate the radiation dose, the CT parameters influencing the radiation dose, dose comparisons between CT and most other imaging techniques of the chest, the newly developed so called "Low-Dose" CT techniques and highlights some of the unresolved questions related to radiation dose in clinical CT practice.

  2. Is the use of the cervical vertebrae maturation method justified to determine skeletal age? A comparison of radiation dose of two strategies for skeletal age estimation.

    PubMed

    Patcas, Raphael; Signorelli, Luca; Peltomäki, Timo; Schätzle, Marc

    2013-10-01

    The aim of this study was to assess effective doses of a lateral cephalogram radiograph with and without thyroid shield and compare the differences with the radiation dose of a hand-wrist radiograph. Thermoluminescent dosimeters were placed at 19 different sites in the head and neck of a tissue-equivalent human skull (RANDO phantom). Analogue lateral cephalograms with and without thyroid shield (67 kV, 250 mA, 10 mAs) and hand-wrist radiographs (40 kV, 250 mA, 10 mAs) were obtained. The effective doses were calculated using the 2007 International Commission on Radiological Protection recommendations. The effective dose for conventional lateral cephalogram without a thyroid shield was 5.03 microsieverts (µSv). By applying a thyroid shield to the RANDO phantom, a remarkable dose reduction of 1.73 µSv could be achieved. The effective dose of a conventional hand-wrist radiograph was calculated to be 0.16 µSv. Adding the effective dose of the hand-wrist radiograph to the effective dose of the lateral cephalogram with thyroid shield resulted in a cumulative effective dose of 3.46 µSv. Without thyroid shield, the effective dose of a lateral cephalogram was approximately 1.5-fold increased than the cumulative effective dose of a hand-wrist radiograph and a lateral cephalogram with thyroid shield. Thyroid is an organ that is very sensitive to radiation exposure. Its shielding will significantly reduce the effective dose. An additional hand-wrist radiograph, involving no vulnerable tissues, however, causes very little radiation risk. In accordance with the ALARA (As Low As Reasonably Achievable) principle, if an evaluation of skeletal age is indicated, an additional hand-wrist radiograph seems much more justifiable than removing the thyroid shield.

  3. Feasibility of using sup 129 I concentrations in human tissue to estimate radiation dose from sup 131 I

    SciTech Connect

    McCormack, W.D.

    1989-10-01

    To use data on {sup 129}I in human tissue to estimate an individual's past exposure to that radionuclide, it is necessary to know when and how the exposure occurred, and to know about any other prior and/or ongoing exposures. Moreover, to use {sup 129}I data to estimate past exposure to {sup 131}I, it is also necessary to know the relationship of the two radionuclides at the time of exposure. The relative quantities of {sup 131}I and {sup 129}I in gaseous effluents from Hanford Site facilities varied significantly because of the large variations in elapsed time between discharge of irradiated fuel from Hanford production reactors and initiation of chemical processing. The relationship of the two radionuclides also varied in the environment because the shorter-lived {sup 131}I decayed and the longer-lived {sup 129}I accumulated. Because of its extremely long half-life, {sup 129}I from both Hanford and non-Hanford sources (such as fallout from weapons testing) has accumulated in the environment. Without an associated exposure to {sup 131}I, chronic exposure to {sup 129}I deposited in the environment has contributed and continues to contribute to thyroid burdens. Based on investigations conducted to date, measured levels of {sup 129}I in human tissue will not provide a viable alternative for reconstruction of historical exposure to {sup 131}I. 5 refs.

  4. Coronary CT angiography with low radiation dose.

    PubMed

    Xu, Lei; Zhang, Zhaoqi

    2010-02-01

    With the introduction of 64-slice CT and dual-source CT technology, coronary CT angiography(CCTA) has emerged as a useful diagnostic imaging modality for the noninvasive assessment of coronary heart disease. Recently, the risks associated with ionizing radiation on CT have raised serious concerns.The main concern of exposure to ionizing radiation is the potential risk of cancer. CCTA involves much higher radiation dose with the advances in the spatial and temporal resolution of cardiac CT. Currently,various dose-saving algorithms, such as ECG (electrocardiography)-based dose modulation, reduced tube voltage, and prospective ECG gating, high-pitch helical scanning are available to lower radiation exposure during cardiac CT. Therefore, careful selection of CT scanning protocols is needed to keep the radiation exposure 'as low as reasonably achievable (ALARA)'. In this review we will discuss the radiation dose safety issues, the measurement of radiation dose and current use of dose-saving techniques in CCTA.

  5. Benzene risk estimation using radiation equivalent coefficients.

    PubMed

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

    2009-03-01

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

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

    SciTech Connect

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

    2002-10-01

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

  7. Ultraviolet radiation therapy and UVR dose models

    SciTech Connect

    Grimes, David Robert

    2015-01-15

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

  8. Ultraviolet radiation therapy and UVR dose models.

    PubMed

    Grimes, David Robert

    2015-01-01

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

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

    PubMed

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

    2010-01-01

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

  10. Radiation dose from cigarette tobacco

    SciTech Connect

    Papastefanou, C.

    2008-08-07

    The radioactivity in tobacco leaves collected from 15 different regions of Greece before cigarette production was studied in order to estimate the effective dose from cigarette tobacco due to the naturally occurring primordial radionuclides, such as {sup 226}Ra and {sup 210}Pb of the uranium series and {sup 228}Ra of the thorium series and/or man-made produced radionuclides, such as {sup 137}Cs of Chernobyl origin. Gamma-ray spectrometry was applied using Ge planar and coaxial type detectors of high resolution and high efficiency. It was concluded that the annual effective dose due to inhalation for adults (smokers) for {sup 226}Ra varied from 42.5 to 178.6 {mu}Sv y{sup -1} (average 79.7 {mu}Sv y{sup -1}), while for {sup 228}Ra from 19.3 to 116.0 {mu}Sv y{sup -1} (average 67.1 {mu}Sv y{sup -1}) and for {sup 210}Pb from 47.0 to 134.9 {mu}Sv y{sup -1} (average 104.7 {mu}Sv y{sup -1}), that is the same order of magnitude for each radionuclide. The sum of the effective dose of the three natural radionuclides varied from 151.9 to 401.3 {mu}Sv y{sup -1} (average 251.5 {mu}Sv y{sup -1}). The annual effective dose from {sup 137}Cs of Chernobyl origin was three orders of magnitude lower as it varied from 70.4 to 410.4 nSv y{sup -1} (average 199.3 nSv y{sup -1})

  11. Radiation Dose from Cigarette Tobacco

    NASA Astrophysics Data System (ADS)

    Papastefanou, C.

    2008-08-01

    The radioactivity in tobacco leaves collected from 15 different regions of Greece before cigarette production was studied in order to estimate the effective dose from cigarette tobacco due to the naturally occurring primordial radionuclides, such as 226Ra and 210Pb of the uranium series and 228Ra of the thorium series and/or man-made produced radionuclides, such as 137Cs of Chernobyl origin. Gamma-ray spectrometry was applied using Ge planar and coaxial type detectors of high resolution and high efficiency. It was concluded that the annual effective dose due to inhalation for adults (smokers) for 226Ra varied from 42.5 to 178.6 μSv y-1 (average 79.7 μSv y-1), while for 228Ra from 19.3 to 116.0 μSv y-1 (average 67.1 μSv y-1) and for 210Pb from 47.0 to 134.9 μSv y-1 (average 104.7 μSv y-1), that is the same order of magnitude for each radionuclide. The sum of the effective dose of the three natural radionuclides varied from 151.9 to 401.3 μSv y-1 (average 251.5 μSv y-1). The annual effective dose from 137Cs of Chernobyl origin was three orders of magnitude lower as it varied from 70.4 to 410.4 nSv y-1 (average 199.3 nSv y-1).

  12. Comparison of Radiation Dose Estimation for Myeloablative Radioimmunotherapy for Relapsed or Recurrent Mantle Cell Lymphoma using 131I Tositumomab to that of Other Types of Non-Hodgkin's Lymphoma

    SciTech Connect

    Rajendran, Joseph G.; Gopal, Ajay K.; Durack, Larry; Fisher, Darrell R.; Press, Oliver W.; Eary, Janet F.

    2004-12-01

    Patients with relapsed or refractory mantle cell lymphoma (MCL) demonstrate poor survival after standard treatment. Myeloablative radioimmunotherapy (RIT) using 131I tositumomab (anti-CD20) has the ability to deliver specific radiation absorbed dose to antigen bearing tumor. We reviewed normal organ radiation absorbed doses in MCL patients. METHODS: Records of patients with MCL (n = 25), who received myeloablative RIT between January 1996 and December 2003 were reviewed. Individual patient radiation dosimetry was performed on all patients after a trace labeled infusion of 131I tositumomab (mean = 348 MBq), to calculate the required amount of radioactivity for therapy, based on MIRD schema. RESULTS: Mean organ residence times (hr) corrected for CT derived organ volumes for MCL, were as follows: Lungs:9.0; Liver:12.4; Kidneys:1.7; Spleen:2.17; Whole Body:62.4 and mean radiation absorbed doses mGy/Mbq were: Lungs:1.2; Liver:1.1; Kidneys:0.85; Spleen:1.7; Whole Body: 0.21. This is similar to patients with other NHL. Patients received a mean activity of 21 GBq of 131I (range = 11.5 - 41.4) for therapy estimated to deliver 25 Gy to the normal organ receiving the highest radiation absorbed dose. CONCLUSION: Myeloablative RIT using 131I tositumomab results in normal organ radiation absorbed doses similar to those in patients with other non-Hodgkin's lymphoma, and is suitable for treating patients with relapsed or refractory MCL.

  13. CT radiation dose awareness among paediatricians.

    PubMed

    Al-Rammah, Tamader Y

    2016-08-31

    The radiation dose delivered from computed tomography (CT) scanning and the risks associated with ionising radiation are major concerns in paediatric imaging. Compared to adults, children have increased organ sensitivity and a longer expected lifetime in which cancer may develop. Therefore, it is important to investigate the awareness of paediatricians (referring physicians) regarding radiation doses and the associated risks. A multiple-choice survey was distributed among paediatricians in 8 hospitals in Riyadh, the capital of Saudi Arabia. Among the 162 respondents, only 24 (15 %) were aware of the As Low As Reasonably Achievable (ALARA) principle. Approximately half (54 %) of the respondents believed that multi-slice CT delivered a low radiation dose, and 100 (62 %) of the respondents were not aware that radiation is considered carcinogenic by the Food and Drug Administration in the United States. Among the respondents, 110 (68 %) did not have any specific education regarding radiation during their training. There was an overall underestimation (83 %) of the CT radiation dose, and 70 % thought that magnetic resonance imaging (MRI) delivered some level of ionising radiation. Among paediatricians in Saudi Arabian hospitals, there was a wide underestimation of the CT radiation dose and the associated risks for children. We should improve paediatricians' knowledge about radiation doses. Radiologists, paediatricians, radiation technologists and medical physicists should work together to optimise CT guidelines and protocols to reduce the radiation risks for children.

  14. Estimation of thyroid radiation doses for the hanford thyroid disease study: results and implications for statistical power of the epidemiological analyses.

    PubMed

    Kopecky, Kenneth J; Davis, Scott; Hamilton, Thomas E; Saporito, Mark S; Onstad, Lynn E

    2004-07-01

    Residents of eastern Washington, northeastern Oregon, and western Idaho were exposed to I released into the atmosphere from operations at the Hanford Nuclear Site from 1944 through 1972, especially in the late 1940's and early 1950's. This paper describes the estimated doses to the thyroid glands of the 3,440 evaluable participants in the Hanford Thyroid Disease Study, which investigated whether thyroid morbidity was increased in people exposed to radioactive iodine from Hanford during 1944-1957. The participants were born during 1940-1946 to mothers living in Benton, Franklin, Walla Walla, Adams, Okanogan, Ferry, or Stevens Counties in Washington State. Whenever possible someone with direct knowledge of the participant's early life (preferably the participant's mother) was interviewed about the participant's individual dose-determining characteristics (residence history, sources and quantities of food, milk, and milk products consumed, production and processing techniques for home-grown food and milk products). Default information was used if no interview respondent was available. Thyroid doses were estimated using the computer program Calculation of Individual Doses from Environmental Radionuclides (CIDER) developed by the Hanford Environmental Dose Reconstruction Project. CIDER provided 100 sets of doses to represent uncertainty of the estimates. These sets were not generated independently for each participant, but reflected the effects of uncertainties in characteristics shared by participants. Estimated doses (medians of each participant's 100 realizations) ranged from 0.0029 mGy to 2823 mGy, with mean and median of 174 and 97 mGy, respectively. The distribution of estimated doses provided the Hanford Thyroid Disease Study with sufficient statistical power to test for dose-response relationships between thyroid outcomes and exposure to Hanford's I.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

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

    PubMed

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

    2004-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  19. ESTIMATING SOLAR RADIATION EXPOSURE IN WETLANDS USING RADIATION MODELS, FIELD DATA, AND GEOGRAPHIC INFORMATION SYSTEMS

    EPA Science Inventory

    This seminar will describe development of methods for the estimation of solar radiation doses in wetlands. The methodology presents a novel approach to incorporating aspects of solar radiation dosimetry that have historically received limited attention. These include effects of a...

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

    PubMed

    Stefanou, E P

    1988-01-01

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

  1. ret/PTC Activation Is Not Associated with Individual Radiation Dose Estimates in a Pilot Study of Neoplastic Thyroid Nodules Arising in Russian Children and Adults Exposed to Chernobyl Fallout

    PubMed Central

    Lukes, Yvonne; Onstad, Lynn; Lushnikov, Eugeni; Abrosimov, Alexander; Troshin, Vladislav; Tsyb, Anatoli; Davis, Scott; Kopecky, Kenneth J.; Francis, Gary

    2008-01-01

    Background Ionizing radiation is the strongest risk factor known for the development of thyroid neoplasia. While previous studies have demonstrated a high prevalence of ret/papillary thyroid cancer (PTC) activation in cohorts of patients developing thyroid nodules after childhood exposure to ionizing radiation, no study has directly compared ret/PTC activation with individual estimates of radiation dose to the thyroid. This study combines individual thyroid dosimetry data with molecular analysis of surgically removed thyroid nodules in order to determine if ret/PTC activation in thyroid nodules is associated with increasing estimated radiation dose from Chernobyl. Methods This pilot study included adults and children diagnosed with PTC (n = 76) and children diagnosed with follicular adenomas (n = 24) during May 1986 through December 1999, who were living in the Bryansk Oblast of the Russian Federation at the time of the Chernobyl accident, who had paraffin-embedded thyroid surgical samples available and for whom an individual dose to the thyroid could be estimated. The frequency of ret/PTC activation was determined using RT-PCR analysis. Individual radiation doses to the thyroid were estimated using a semiempirical model, and data were collected by detailed interview, primarily of the participant's mother. Results ret/PTC oncogene activation was detected in 23.8% (5/21) and 14.5% (8/55) of the childhood and adult PTC cases, respectively, and 8.3% (2/24) of the follicular adenoma cases. No statistically significant differences were noted in age at the time of exposure or diagnosis, gender, latency period, or estimated radiation dose between PTC patients with or without ret/PTC activation. Further, no significant dose–response relationship was detected among PTC patients with ret/PTC activation. Conclusions Factors other than individual thyroid radiation doses may influence the development and subsequent detection of ret/PTC oncogene activation in radiation

  2. Radiation transport simulation of the Martian GCR surface flux and dose estimation using spherical geometry in PHITS compared to MSL-RAD measurements

    NASA Astrophysics Data System (ADS)

    Flores-McLaughlin, John

    2017-08-01

    Planetary bodies and spacecraft are predominantly exposed to isotropic radiation environments that are subject to transport and interaction in various material compositions and geometries. Specifically, the Martian surface radiation environment is composed of galactic cosmic radiation, secondary particles produced by their interaction with the Martian atmosphere, albedo particles from the Martian regolith and occasional solar particle events. Despite this complex physical environment with potentially significant locational and geometric dependencies, computational resources often limit radiation environment calculations to a one-dimensional or slab geometry specification. To better account for Martian geometry, spherical volumes with respective Martian material densities are adopted in this model. This physical description is modeled with the PHITS radiation transport code and compared to a portion of measurements from the Radiation Assessment Detector of the Mars Science Laboratory. Particle spectra measured between 15 November 2015 and 15 January 2016 and PHITS model results calculated for this time period are compared. Results indicate good agreement between simulated dose rates, proton, neutron and gamma spectra. This work was originally presented at the 1st Mars Space Radiation Modeling Workshop held in 2016 in Boulder, CO.

  3. Radiation dose of CT coronary angiography in clinical practice: objective evaluation of strategies for dose optimization.

    PubMed

    Yerramasu, Ajay; Venuraju, Shreenidhi; Atwal, Satvir; Goodman, Dennis; Lipkin, David; Lahiri, Avijit

    2012-07-01

    CT coronary angiography (CTCA) is an evolving modality for the diagnosis of coronary artery disease. Radiation burden associated with CTCA has been a major concern in the wider application of this technique. It is important to reduce the radiation dose without compromising the image quality. To estimate the radiation dose of CTCA in clinical practice and evaluate the effect of dose-saving algorithms on radiation dose and image quality. Effective radiation dose was measured from the dose-length product in 616 consecutive patients (mean age 58 ± 12 years; 70% males) who underwent clinically indicated CTCA at our institution over 1 year. Image quality was assessed subjectively using a 4-point scale and objectively by measuring the signal- and contrast-to-noise ratios in the coronary arteries. Multivariate linear regression analysis was used to identify factors independently associated with radiation dose. Mean effective radiation dose of CTCA was 6.6 ± 3.3 mSv. Radiation dose was significantly reduced by dose saving algorithms such as 100 kV imaging (-47%; 95% CI, -44% to -50%), prospective gating (-35%; 95% CI, -29% to -40%) and ECG controlled tube current modulation (-23%; 95% CI, -9% to -34%). None of the dose saving algorithms were associated with a significant reduction in mean image quality or the frequency of diagnostic scans (P = non-significant for all comparisons). Careful application of radiation-dose saving algorithms in appropriately selected patients can reduce the radiation burden of CTCA significantly, without compromising the image quality. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  4. Low-dose radiation: a cause of breast cancer

    SciTech Connect

    Land, C.E.

    1980-08-15

    It is likely that the breast is the organ most sensitive to radiation carcinogenesis in postpubertal women. Studies of different exposed populations have yielded remarkably consistent results, in spite of wide differences in underlying breast cancer rates and conditions of exposure. Excess risk is approximately proportional to dose, and is relatively independent of ionization density and fractionization of dose. This implies that the risk associated with low-dose exposures to ionizing radiation can be estimated with some confidence from higher-dose data. Excess risk is heavily dependent on age at exposure but relatively independent of population differences in normal risk. The temporal patterns after exposure of both radiation-induced and naturally occurring breast cancer are similar, suggesting a strong influence of factors other than radiation on radiation-induced breast cancer. Uncertainties remain about risks from exposures before puberty and after menopause.

  5. Potential radiation doses from 1994 Hanford Operations

    SciTech Connect

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

    1995-06-01

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

  6. Principles of estimation of Radiative danger

    NASA Astrophysics Data System (ADS)

    Korogodin, V. I.

    1990-08-01

    The main principles of the estimation of Radiative danger has been discussed. Two main particularities of the danger were pointed out: negatve consequencies of small doses, which does not lead to radiation sickness, but lead to disfunctions of sanguine organs and thin intestines; absolute estimation of biological anomalies, which was forwarded by A.D. Sakharov (1921-1989). The ethic aspects of the use of Nuclear weapons on the fate of Human civilization were pointed out by A.D. Sakharov (1921-1990).

  7. Simulations of space radiation interactions with materials, with application to dose estimates for lunar shelter and aboard the International Space Station

    NASA Astrophysics Data System (ADS)

    Pham, Tai T.

    This research performed simulations using the state-of-art three dimensional computer codes to investigate the interactions of space radiation with materials and quantify the biological dose onboard the International Space Station (ISS) and in a lunar shelter for future manned missions. High-energy space radiation of Trapped Protons, Solar Particle Events, and GCRs particles interactions are simulated using MCNPX and PHITS probabilistic codes. The energy loss and energy deposition within the shielding materials and in a phantom are calculated. The contributions of secondary particles produced by spallation reactions are identified. Recent experimental measurements of absorbed dose in a phantom aboard the International Space Station (ISS) was simulated, and used to determine the most appropriate simulation methodology.

  8. Effective dose estimation during conventional and CT urography

    NASA Astrophysics Data System (ADS)

    Alzimami, K.; Sulieman, A.; Omer, E.; Suliman, I. I.; Alsafi, K.

    2014-11-01

    Intravenous urography (IVU) and CT urography (CTU) are efficient radiological examinations for the evaluation of the urinary system disorders. However patients are exposed to a significant radiation dose. The objectives of this study are to: (i) measure and compare patient radiation dose by computed tomography urography (CTU) and conventional intravenous urography (IVU) and (ii) evaluate organ equivalent dose and cancer risks from CTU and IVU imaging procedures. A total of 141 patients were investigated. A calibrated CT machine (Siemens-Somatom Emotion duo) was used for CTU, while a Shimadzu X ray machine was used for IVU. Thermoluminescence dosimeters (TLD-GR200A) were used to measure patients' entrance surface doses (ESD). TLDs were calibrated under reproducible reference conditions. Patients radiation dose values (DLP) for CTU were 172±61 mGy cm, CTDIvol 4.75±2 mGy and effective dose 2.58±1 mSv. Patient cancer probabilities were estimated to be 1.4 per million per CTU examination. Patients ESDs values for IVU were 21.62±5 mGy, effective dose 1.79±1 mSv. CT involves a higher effective dose than IVU. In this study the radiation dose is considered low compared to previous studies. The effective dose from CTU procedures was 30% higher compared to IVU procedures. Wide dose variation between patient doses suggests that optimization is not fulfilled yet.

  9. Estimated Radiation Dosage on Mars

    NASA Image and Video Library

    2002-03-01

    This global map of Mars, based on data from NASA Mars Odyssey, shows the estimated radiation dosages from cosmic rays reaching the surface, a serious health concern for any future human exploration of the planet.

  10. Maximum likelihood estimation for cytogenetic dose-response curves

    SciTech Connect

    Frome, E.L.; DuFrain, R.J.

    1986-03-01

    In vitro dose-response curves are used to describe the relation between chromosome aberrations and radiation dose for human lymphocytes. The lymphocytes are exposed to low-LET radiation, and the resulting dicentric chromosome aberrations follow the Poisson distribution. The expected yield depends on both the magnitude and the temporal distribution of the dose. A general dose-response model that describes this relation has been presented by Kellerer and Rossi (1972, Current Topics on Radiation Research Quarterly 8, 85-158; 1978, Radiation Research 75, 471-488) using the theory of dual radiation action. Two special cases of practical interest are split-dose and continuous exposure experiments, and the resulting dose-time-response models are intrinsically nonlinear in the parameters. A general-purpose maximum likelihood estimation procedure is described, and estimation for the nonlinear models is 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.

  11. Occupational radiation doses during interventional procedures

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  12. Time-dependent estimates of organ dose and dose equivalent rates for human crews in deep space from the 26 October 2003 solar energetic particle event (Halloween event) using the Earth-Moon-Mars Radiation Environment Module

    NASA Astrophysics Data System (ADS)

    PourArsalan, M.; Townsend, L. W.; Schwadron, N. A.; Kozarev, K.; Dayeh, M. A.; Desai, M. I.

    2010-08-01

    The Earth-Moon-Mars Radiation Environment Module is being developed for use by a broad spectrum of researchers to predict energetic particle intensities and radiation exposures at any location in deep space. In this work we demonstrate the capabilities of the module for performing analyses of time-dependent exposures from solar energetic particle events at various locations in space by calculating cumulative dose and dose equivalent, and their time rates of change, for the skin and bone marrow of crew members shielded by as much as 10 g/cm2 of aluminum shielding for the Halloween events of late October 2003.

  13. Adaption By Low Dose Radiation Exposure

    PubMed Central

    2015-01-01

    The procedures and dose limitations used for radiation protection in the nuclear industry are founded on the assumption that risk is directly proportional to dose, without a threshold. Based on this idea that any dose, no matter how small, will increase risk, radiation protection regulations generally attempt to reduce any exposure to “as low as reasonably achievable” (ALARA). We know however, that these regulatory assumptions are inconsistent with the known biological effects of low doses. Low doses induce protective effects, and these adaptive responses are part of a general response to low stress. Adaptive responses have been tightly conserved during evolution, from single celled organisms up to humans, indicating their importance. Here we examine cellular and animal studies that show the influence of radiation induced protective effects on diverse diseases, and examine the radiation dose range that is effective for different tissues in the same animal. The concept of a dose window, with upper and lower effective doses, as well as the effect of multiple stressors and the influence of genetics will also be examined. The effect of the biological variables on low dose responses will be considered from the point of view of the limitations they may impose on any revised radiation protection regulations. PMID:26672725

  14. Radiation dose optimization in thoracic imaging.

    PubMed

    Tack, D

    2010-01-01

    Guidelines for reduction of CT radiation dose were introduced in 1997 and are now more than 12 years old. The process initiated by the European Regulatory authorities to reduce the excess of radiation from CT has however not produced the expected results. Reference diagnostic levels (DRL) from surveys are still twice as high as needed in most European countries and were not significantly reduced as compared to the initial European ones. Many factors may at least explain partially the lack of dose reduction. One of them is the complexity of the dose optimization process while maintaining image quality at a diagnostically acceptable level. Chest is an anatomical region where radiation dose could be substantially reduced because of high natural contrasts between structures, such as air in the lungs and fat in the mediastinum. In this article, the concept of CT radiation dose optimization and the factors that contribute to maintain global excess in radiation dose are reviewed and a brief summary of results from research in the field of chest CT radiation dose is given.

  15. Patient Radiation Doses from Diagnostic Radiology.

    ERIC Educational Resources Information Center

    Hart, D.

    1996-01-01

    Explains how x-ray doses to patients are measured. Describes how different techniques expose patients to differing amounts of ionizing radiation. Compares these figures with other natural and man-made sources. (Author/MKR)

  16. Estimate of doses to the fetus during commercial flights.

    PubMed

    Chen, Jing; Mares, Vladimir

    2008-10-01

    This study assesses the radiation exposure from cosmic rays to fetuses of pregnant aircrew and air travelers. Combining the particle fluence spectra of various cosmic radiations at aircraft altitudes with the fetal fluence-to-dose conversion coefficients calculated for different cosmic ray radiations, the doses to the fetal body were estimated for three prenatal ages. From the five major particle types present during commercial flights, neutrons contribute about 54% of the total fetal dose, followed by protons 22%, photons 11%, electrons 7%, and muons 6%. The results indicate that the dose to the fetus can exceed a recommended fetal dose limit of 1 mSv after 10 round trips on commercial flights between Toronto and Frankfurt.

  17. Gamma Radiation Doses In Sweden

    SciTech Connect

    Almgren, Sara; Isaksson, Mats; Barregaard, Lars

    2008-08-07

    Gamma dose rate measurements were performed in one urban and one rural area using thermoluminescence dosimeters (TLD) worn by 46 participants and placed in their dwellings. The personal effective dose rates were 0.096{+-}0.019(1 SD) and 0.092{+-}0.016(1 SD){mu}Sv/h in the urban and rural area, respectively. The corresponding dose rates in the dwellings were 0.11{+-}0.042(1 SD) and 0.091{+-}0.026(1 SD){mu}Sv/h. However, the differences between the areas were not significant. The values were higher in buildings made of concrete than of wood and higher in apartments than in detached houses. Also, {sup 222}Rn measurements were performed in each dwelling, which showed no correlation with the gamma dose rates in the dwellings.

  18. Low-dose radiation exposure and carcinogenesis.

    PubMed

    Suzuki, Keiji; Yamashita, Shunichi

    2012-07-01

    Absorption of energy from ionizing radiation by the genetic material in the cell leads to damage to DNA, which in turn leads to cell death, chromosome aberrations and gene mutations. While early or deterministic effects result from organ and tissue damage caused by cell killing, latter two are considered to be involved in the initial events that lead to the development of cancer. Epidemiological studies have demonstrated the dose-response relationships for cancer induction and quantitative evaluations of cancer risk following exposure to moderate to high doses of low-linear energy transfer radiation. A linear, no-threshold model has been applied to assessment of the risks resulting from exposure to moderate and high doses of ionizing radiation; however, a statistically significant increase has hardly been described for radiation doses below 100 mSv. This review summarizes our current knowledge of the physical and biological features of low-dose radiation and discusses the possibilities of induction of cancer by low-dose radiation.

  19. Development of a kinetic model and calculation of radiation dose estimates for sodium iodide-{sup 131}I in athyroid individuals

    SciTech Connect

    Rodriguez, M.

    1997-07-01

    The treatment for some thyroid carcinomas involves surgically removing the thyroid gland and administering the radiopharmaceutical Sodium iodide-{sup 131}I (NaI). A diagnostic dose of NaI is given to the patient to determine if remnant tissue from the gland remains or larger doses are administered in order to treat the malignant tissue. Past research regarding NaI uptake and retention in euthyroid individuals (normal functioning thyroid) reveal that radioiodine concentrates mainly in the thyroid tissue and the remaining material is excreted from the body. The majority of radioiodine in athyroid (without thyroid) individuals is also eliminated from the body; however, there has been recent evidence of a long-term retention phase for individuals with no radioiodine concentrating tissue. The general purpose of this study was to develop a kinetic model and estimate the absorbed dose to athyroid individuals regarding the distribution and retention of NaI.

  20. Principles of CT: radiation dose and image quality.

    PubMed

    Goldman, Lee W

    2007-12-01

    This article discusses CT radiation dose, the measurement of CT dose, and CT image quality. The most commonly used dose descriptor is CT dose index, which represents the dose to a location (e.g., depth) in a scanned volume from a complete series of slices. A weighted average of the CT dose index measured at the center and periphery of dose phantoms provides a convenient single-number estimate of patient dose for a procedure, and this value (or a related indicator that includes the scanned length) is often displayed on the operator's console. CT image quality, as in most imaging, is described in terms of contrast, spatial resolution, image noise, and artifacts. A strength of CT is its ability to visualize structures of low contrast in a subject, a task that is limited primarily by noise and is therefore closely associated with radiation dose: The higher the dose contributing to the image, the less apparent is image noise and the easier it is to perceive low-contrast structures. Spatial resolution is ultimately limited by sampling, but both image noise and resolution are strongly affected by the reconstruction filter. As a result, diagnostically acceptable image quality at acceptable doses of radiation requires appropriately designed clinical protocols, including appropriate kilovolt peaks, amperages, slice thicknesses, and reconstruction filters.

  1. Radiation dose to the walls of hollow organs

    SciTech Connect

    Stabin, M.G.; Stubbs, J.B.

    1994-05-01

    The radiation doses to the walls of hollow organs, from activity in their contents, have traditionally been estimated as the sum of the photon dose to the wall and the maximum electron/beta dose. The photon dose is usually estimated by Monte Carlo methods, and the nonpenetrating dose estimated as the surface dose, equal to one half of the average dose to the volume. Some clinical experience, such as lack of radiotoxicity in patients estimated to have received more than 10 Gy to the walls of organs in the GI tract, led us to investigate the appropriateness of this approach. While the photon dose is thought to be fairly uniform throughout the walls of hollow organs, the electron and beta doses drop off rapidly from a maximum at the surface of the organ`s contents to zero at distances dependent on emission energy. The degree to which the activity is separated from the target cells in the wall, the uniformity of activity distribution within the contents, and the location of the cells at risk for tissue injury and carcinogenesis are some of the issues which determine the appropriate dose(s) to report. For example, in the stomach, the wall thickness varies from 0.6-1.3 cm. The epithelial surface mucus cells are 20-40 micrometers in height, and are located beneath a mucus layer which varies typically between about 0.18 and 0.6 mm in thickness This layer is thus thick enough to attenuate almost all of the electron energy emitted from Tc-99m and I-123 and 26-50% of the beta energy of Y-90. The maximum dose to the surface mucus cells, or a volume averaged dose to these and other cells, may be a better predictor of radiation effects than the maximum dose at the surface of the contents.

  2. Head and Neck Radiation Dose and Radiation Safety for Interventional Physicians.

    PubMed

    Fetterly, Kenneth; Schueler, Beth; Grams, Michael; Sturchio, Glenn; Bell, Malcolm; Gulati, Rajiv

    2017-03-13

    The first aim of this study was to assess the magnitude of radiation dose to tissues of the head and neck of physicians performing x-ray-guided interventional procedures. The second aim was to assess protection of tissues of the head offered by select wearable radiation safety devices. Radiation dose to tissues of the head and neck is of significant interest to practicing interventional physicians. However, methods to estimate radiation dose are not generally available, and furthermore, some of the available research relating to protection of these tissues is misleading. Using a single representative geometry, scatter radiation dose to a humanoid phantom was measured using radiochromic film and normalized by the radiation dose to the left collar of the radioprotective thorax apron. Radiation protection offered by leaded glasses and by a radioabsorbent surgical cap was measured. In the test geometry, average radiation doses to the unprotected brain, carotid arteries, and ocular lenses were 8.4%, 17%, and 50% of the dose measured at the left collar, respectively. Two representative types of leaded glasses reduced dose to the ocular lens on the side of the physician from which the scatter originates by 27% to 62% but offered no protection to the contralateral eye. The radioabsorbent surgical cap reduced brain dose by only 3.3%. A method by which interventional physicians can estimate dose to head and neck tissues on the basis of their personal dosimeter readings is described. Radiation protection of the ocular lenses by leaded glasses may be incomplete, and protection of the brain by a radioabsorbent surgical cap was minimal. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  3. Radiation measurements and doses at SST altitudes

    NASA Technical Reports Server (NTRS)

    Foelsche, T.

    1972-01-01

    Radiation components and dose equivalents due to galactic and solar cosmic rays in the high atmosphere, especially at SST altitudes, are presented. The dose equivalent rate for the flight personnel flying 500 hours per year in cruise altitudes of 60,000-65,000 feet (18-19.5 km) in high magnetic latitudes is about 0.75-1.0 rem per year averaged over the solar cycle, or about 15-20 percent of the maximum permissible dose rate.

  4. Radiation dose estimation for marine mussels following exposure to tritium: Best practice for use of the ERICA tool in ecotoxicological studies.

    PubMed

    Dallas, Lorna J; Devos, Alexandre; Fievet, Bruno; Turner, Andrew; Lyons, Brett P; Jha, Awadhesh N

    2016-05-01

    Accurate dosimetry is critically important for ecotoxicological and radioecological studies on the potential effects of environmentally relevant radionuclides, such as tritium ((3)H). Previous studies have used basic dosimetric equations to estimate dose from (3)H exposure in ecologically important organisms, such as marine mussels. This study compares four different methods of estimating dose to adult mussels exposed to 1 or 15 MBq L(-1) tritiated water (HTO) under laboratory conditions. These methods were (1) an equation converting seawater activity concentrations to dose rate with fixed parameters; (2) input into the ERICA tool of seawater activity concentrations only; (3) input into the ERICA tool of estimated whole organism concentrations (woTACs), comprising dry activity plus estimated tissue free water tritium (TFWT) activity (TFWT volume × seawater activity concentration); and (4) input into the ERICA tool of measured whole organism activity concentrations, comprising dry activity plus measured TFWT activity (TFWT volume × TFWT activity concentration). Methods 3 and 4 are recommended for future ecotoxicological experiments as they produce values for individual animals and are not reliant on transfer predictions (estimation of concentration ratio). Method 1 may be suitable if measured whole organism concentrations are not available, as it produced results between 3 and 4. As there are technical complications to accurately measuring TFWT, we recommend that future radiotoxicological studies on mussels or other aquatic invertebrates measure whole organism activity in non-dried tissues (i.e. incorporating TFWT and dry activity as one, rather than as separate fractions) and input this data into the ERICA tool.

  5. Assessment of background gamma radiation levels using airborne gamma ray spectrometer data over uranium deposits, Cuddapah Basin, India - A comparative study of dose rates estimated by AGRS and PGRS.

    PubMed

    Srinivas, D; Ramesh Babu, V; Patra, I; Tripathi, Shailesh; Ramayya, M S; Chaturvedi, A K

    2017-02-01

    The Atomic Minerals Directorate for Exploration and Research (AMD) has conducted high-resolution airborne gamma ray spectrometer (AGRS), magnetometer and time domain electromagnetic (TDEM) surveys for uranium exploration, along the northern margins of Cuddapah Basin. The survey area includes well known uranium deposits such as Lambapur-Peddagattu, Chitrial and Koppunuru. The AGRS data collected for uranium exploration is utilised for estimating the average absorbed rates in air due to radio-elemental (potassium in %, uranium and thorium in ppm) distribution over these known deposit areas. Further, portable gamma ray spectrometer (PGRS) was used to acquire data over two nearby locations one from Lambapur deposit, and the other from known anomalous zone and subsequently average gamma dose rates were estimated. Representative in-situ rock samples were also collected from these two areas and subjected to radio-elemental concentration analysis by gamma ray spectrometer (GRS) in the laboratory and then dose rates were estimated. Analyses of these three sets of results complement one another, thereby providing a comprehensive picture of the radiation environment over these deposits. The average absorbed area wise dose rate level is estimated to be 130 ± 47 nGy h(-1) in Lambapur-Peddagattu, 186 ± 77 nGy h(-1) in Chitrial and 63 ± 22 nGy h(-1) in Koppunuru. The obtained average dose levels are found to be higher than the world average value of 54 nGy h(-1). The gamma absorbed dose rates in nGy h(-1) were converted to annual effective dose rates in mSv y(-1) as proposed by the United Nations Scientific Committee on the Effect of Atomic Radiation (UNSCEAR). The annual average effective dose rates for the entire surveyed area is 0.12 mSv y(-1), which is much lower than the recommended limit of 1 mSv y(-1) by International Commission on Radiation protection (ICRP). It may be ascertained here that the present study establishes a reference data set (baseline) in these

  6. Individual and collective doses from cosmic radiation in Ireland.

    PubMed

    Colgan, P A; Synnott, H; Fenton, D

    2007-01-01

    This paper assesses the individual and collective doses in Ireland due to cosmic radiation. Information on the exposure to cosmic radiation at ground level is reviewed and published data on the frequency of routes flown by Irish residents is used to calculate the dose due to air travel. Occupational exposure of aircrew is also evaluated. Experimental data on cosmic radiation exposure at ground level is in good agreement with international estimates and the average individual dose is calculated as 300 microSv annually. Published data on international air travel by Irish residents shows a 50% increase in the number of flights taken between 2001 and 2005. This increase is primarily on short-haul flights to Europe, but there have been significant percentage increases in all long-haul flights, with the exception of flights to Africa. The additional per capita dose due to air travel is estimated to be 45 muSv, of which 51% is accumulated on European routes and 34% on routes to the United States. Exposure of aircrew to cosmic radiation is now controlled by legislation and all airlines holding an Air Operator's Certificate issued by the Irish Aviation Authority are required to report annually the doses received by their employees in the previous year. There has been a 75% increase in the number of aircrew receiving doses >1 mSv since 2002. In 2004 and 2005 the average individual doses received by Irish aircrew were 1.8 and 2.0, mSv, respectively. The corresponding per caput dose for the entire population is <3 muSv. While this is low compared with the per caput doses from other sources of cosmic radiation, aircrew exposure represents a higher collective dose than any other identified group of exposed workers in Ireland.

  7. Radiation dose assessment of exposure to depleted uranium.

    PubMed

    Li, Wei Bo; Gerstmann, Udo C; Höllriegl, Vera; Szymczak, Wilfried; Roth, Paul; Hoeschen, Christoph; Oeh, Uwe

    2009-07-01

    Depleted uranium (DU) is claimed to contribute to human health problems, known as the Gulf War Syndrome and the Balkan Syndrome. Quantitative radiation dose is required to estimate the health risk of DU materials. The influences of the solubility parameters in the human alimentary tract and the respiratory tract systems and the aerosol particles size on the radiation dose of DU materials were evaluated. The dose conversion factor of daily urinary excretion of DU is provided. The retention and excretion of DU in the human body after a contamination at a wound site were predicted. Dose coefficients of DU after ingestion and inhalation were calculated using the solubility parameters of the DU corrosion products in simulated gastric and simulated lung fluid, which were determined in the Helmholtz Zentrum München. (238)U is the main radiation dose contributor per 1 Bq of DU materials. The dose coefficients of DU materials were estimated to be 3.5 x 10(-8) and 2.1 x 10(-6) Sv Bq(-1) after ingestion and inhalation for members of the public. The ingestion dose coefficient of DU materials is about 75% of the natural uranium value. The inhalation dose coefficient of DU material is in between those for Type M and Type S according to the category for inhaled materials defined by the International Commission on Radiological Protection. Radiation dose possibly received from DU materials can directly be estimated by using the dose conversion factor provided in this study, if daily urinary excretion of DU is measured.

  8. The consequence of day-to-day stochastic dose deviation from the planned dose in fractionated radiation therapy.

    PubMed

    Paul, Subhadip; Roy, Prasun Kumar

    2016-02-01

    Radiation therapy is one of the important treatment procedures of cancer. The day-to-day delivered dose to the tissue in radiation therapy often deviates from the planned fixed dose per fraction. This day-to-day variation of radiation dose is stochastic. Here, we have developed the mathematical formulation to represent the day-to-day stochastic dose variation effect in radiation therapy. Our analysis shows that that the fixed dose delivery approximation under-estimates the biological effective dose, even if the average delivered dose per fraction is equal to the planned dose per fraction. The magnitude of the under-estimation effect relies upon the day-to-day stochastic dose variation level, the dose fraction size and the values of the radiobiological parameters of the tissue. We have further explored the application of our mathematical formulation for adaptive dose calculation. Our analysis implies that, compared to the premise of the Linear Quadratic Linear (LQL) framework, the Linear Quadratic framework based analytical formulation under-estimates the required dose per fraction necessary to produce the same biological effective dose as originally planned. Our study provides analytical formulation to calculate iso-effect in adaptive radiation therapy considering day-to-day stochastic dose deviation from planned dose and also indicates the potential utility of LQL framework in this context.

  9. Monte Carlo estimation of radiation dose in organs of female and male adult phantoms due to FDG-F18 absorbed in the lungs

    NASA Astrophysics Data System (ADS)

    Belinato, Walmir; Santos, William S.; Silva, Rogério M. V.; Souza, Divanizia N.

    2014-03-01

    The determination of dose conversion factors (S values) for the radionuclide fluorodeoxyglucose (18F-FDG) absorbed in the lungs during a positron emission tomography (PET) procedure was calculated using the Monte Carlo method (MCNPX version 2.7.0). For the obtained dose conversion factors of interest, it was considered a uniform absorption of radiopharmaceutical by the lung of a healthy adult human. The spectrum of fluorine was introduced in the input data file for the simulation. The simulation took place in two adult phantoms of both sexes, based on polygon mesh surfaces called FASH and MASH with anatomy and posture according to ICRP 89. The S values for the 22 internal organs/tissues, chosen from ICRP No. 110, for the FASH and MASH phantoms were compared with the results obtained from a MIRD V phantoms called ADAM and EVA used by the Committee on Medical Internal Radiation Dose (MIRD). We observed variation of more than 100% in S values due to structural anatomical differences in the internal organs of the MASH and FASH phantoms compared to the mathematical phantom.

  10. Radiation Dose and Safety in Cardiac Computed Tomography

    PubMed Central

    Gerber, Thomas C; Kantor, Birgit; McCollough, Cynthia H.

    2009-01-01

    Synopsis As a result of the changes in utilization of imaging procedures that rely on ionizing radiation, the collective dose has increased by over 700% and the annual per-capita dose, by almost 600% over recent years. It is certainly possible that this growing use may have significant effects on public health. Although there are uncertainties related to the accuracy of calculated radiation exposure and the estimated biologic risk, there are measures that can be taken to reduce any potential risks while maintaining diagnostic accuracy. This article will review the existing data regarding biological hazards of radiation exposure associated to medical diagnostic testing, the methodology used to estimate radiation exposure and the measures that can be taken to effectively reduce it. PMID:19766923

  11. Wide-range radiation dose monitor

    DOEpatents

    Kopp, M.K.

    1984-09-20

    A radiation dose-rate monitor is provided which operates in a conventional linear mode for radiation in the 0 to 0.5 R/h range and utilizes a nonlinear mode of operation for sensing radiation from 0.5 R/h to over 500 R/h. The nonlinear mode is achieved by a feedback circuit which adjusts the high voltage bias of the proportional counter, and hence its gas gain, in accordance with the amount of radiation being monitored. This allows compression of readout onto a single scale over the range of 0 to greater than 500 R/h without scale switching operations.

  12. Wide-range radiation dose monitor

    DOEpatents

    Kopp, Manfred K.

    1986-01-01

    A radiation dose-rate monitor is provided which operates in a conventional linear mode for radiation in the 0 to 0.5 R/h range and utilizes a nonlinear mode of operation for sensing radiation from 0.5 R/h to over 500 R/h. The nonlinear mode is achieved by a feedback circuit which adjusts the high voltage bias of the proportional counter, and hence its gas gain, in accordance with the amount of radiation being monitored. This allows compression of readout onto a single scale over the range of 0 to greater than 500 R/h without scale switching operations.

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

    PubMed Central

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

    2012-01-01

    The present study evaluated the acute effects of radiation dose, dose rate and fractionation as well as the energy of protons in hematopoietic cells of irradiated mice. The mice were irradiated with a single dose of 51.24 MeV protons at a dose of 2 Gy and a dose rate of 0.05–0.07 Gy/min or 1 GeV protons at doses of 0.1, 0.2, 0.5, 1, 1.5 and 2 Gy delivered in a single dose at dose rates of 0.05 or 0.5 Gy/min or in five daily dose fractions at a dose rate of 0.05 Gy/min. Sham-irradiated animals were used as controls. The results demonstrate a dose-dependent loss of white blood cells (WBCs) and lymphocytes by up to 61% and 72%, respectively, in mice irradiated with protons at doses up to 2 Gy. The results also demonstrate that the dose rate, fractionation pattern and energy of the proton radiation did not have significant effects on WBC and lymphocyte counts in the irradiated animals. These results suggest that the acute effects of proton radiation on WBC and lymphocyte counts are determined mainly by the radiation dose, with very little contribution from the dose rate (over the range of dose rates evaluated), fractionation and energy of the protons. PMID:20726731

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

    PubMed

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

    2010-09-01

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

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

    SciTech Connect

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

    2010-09-01

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

  16. Radiation dose detection by imaging response in biological targets.

    PubMed

    Jakob, B; Durante, M

    2012-04-01

    Imaging was one of the earliest techniques to quantify radiation dose. While films and active fluorescent detectors are still commonly used in physical dosimetry, biological imaging is emerging as a new method to visualize and quantify radiation dose in biological targets. Methods for biological imaging are normally based on molecular fluorescent probes, labeling chromatin-conjugated molecules or specific repair proteins. Examples are chromatin-binding coumarin compounds, which become fluorescent under irradiation, or the H2AX histone, which is rapidly phosphorylated at sites of DNA double-strand breaks and can be visualized by immunostaining. Many other DNA repair proteins can be expressed with fluorescent targets, such as green fluorescent protein, thus becoming visible for dose estimation in vivo. The possibility to visualize radiation damage in living biological targets is particularly important for repair kinetic studies, for estimating individual radiation response, and for remote control of living samples exposed to radiation, for instance in robotic space missions. In vivo dose monitoring in particle therapy exploits the production of positron emitters by nuclear interaction of the incident beam in the patient's body. Positron emission tomography (PET) can then be used to visualize and quantify the particle dose in the patient, and it can in principle also be used for radiotherapy with high-energy X rays. Alternatively, prompt γ rays or scattered secondary particles are under study for in vivo dosimetry of ion beams in therapy.

  17. Dose build up correction for radiation monitors in high-energy bremsstrahlung photon radiation fields.

    PubMed

    Nair, Haridas G; Nayak, M K; Dev, Vipin; Thakkar, K K; Sarkar, P K; Sharma, D N

    2006-01-01

    Conventional radiation monitors have been found to underestimate the personal dose equivalent in the high-energy bremsstrahlung photon radiation fields encountered near electron storage rings. Depth-dose measurements in a water phantom were carried out with a radiation survey meter in the bremsstrahlung photon radiation fields from a 450 MeV electron storage ring to find out the magnitude of the underestimation. Dose equivalent indicated by the survey meter was found to build up with increase in thickness of water placed in front of the meter up to certain depth and then reduce with further increase in thickness. A dose equivalent build up factor was estimated from the measurements. An absorbed dose build up factor in a water phantom was also estimated from calculations performed using the Monte Carlo codes, EGS-4 and EGSnrc. The calculations are found to be in very good agreement with the measurements. The studies indicate inadequacy of commercially available radiation monitors for radiation monitoring within shielded enclosures and in streaming high-energy photon radiation fields from electron storage rings, and the need for proper correction for use in such radiation fields.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  19. Flight attendant radiation dose from solar particle events.

    PubMed

    Anderson, Jeri L; Mertens, Christopher J; Grajewski, Barbara; Luo, Lian; Tseng, Chih-Yu; Cassinelli, Rick T

    2014-08-01

    Research has suggested that work as a flight attendant may be related to increased risk for reproductive health effects. Air cabin exposures that may influence reproductive health include radiation dose from galactic cosmic radiation and solar particle events. This paper describes the assessment of radiation dose accrued during solar particle events as part of a reproductive health study of flight attendants. Solar storm data were obtained from the National Oceanic and Atmospheric Administration Space Weather Prediction Center list of solar proton events affecting the Earth environment to ascertain storms relevant to the two study periods (1992-1996 and 1999-2001). Radiation dose from exposure to solar energetic particles was estimated using the NAIRAS model in conjunction with galactic cosmic radiation dose calculated using the CARI-6P computer program. Seven solar particle events were determined to have potential for significant radiation exposure, two in the first study period and five in the second study period, and over-lapped with 24,807 flight segments. Absorbed (and effective) flight segment doses averaged 6.5 μGy (18 μSv) and 3.1 μGy (8.3 μSv) for the first and second study periods, respectively. Maximum doses were as high as 440 μGy (1.2 mSv) and 20 flight segments had doses greater than 190 μGy (0.5 mSv). During solar particle events, a pregnant flight attendant could potentially exceed the equivalent dose limit to the conceptus of 0.5 mSv in a month recommended by the National Council on Radiation Protection and Measurements.

  20. Radiation dose to the lens and cataract formation

    SciTech Connect

    Henk, J.M.; Whitelocke, R.A.F.; Warrington, A.P.; Bessell, E.M. )

    1993-04-02

    The purpose of this work was to determine the radiation tolerance of the lens of the eye and the incidence of radiation-induced lens changes in patients treated by fractionated supervoltage radiation therapy for orbital tumors. Forty patients treated for orbital lymphoma and pseudotumor with tumor doses of 20--40 Gy were studied. The lens was partly shielded using lead cylinders in most cases. The dose to the germinative zone of the lens was estimated by measurements in a tissue equivalent phantom using both film densitometry and thermoluminescent dosimetry. Opthalmological examination was performed at 6 monthly intervals after treatment. The lead shield was found to reduce the dose to the germinative zone of the lens to between 36--50% of the tumor dose for Cobalt beam therapy, and to between 11--18% for 5 MeV x-rays. Consequently, the lens doses were in the range 4.5--30 Gy in 10--20 fractions. Lens opacities first appeared from between 3 and 9 years after irradiation. Impairment of visual acuity ensued in 74% of the patients who developed lens opacities. The incidence of lens changes was strongly dose-related. None was seen after doses of 5 Gy or lower, whereas doses of 16.5 Gy or higher were all followed by lens opacities which impaired visual acuity. The largest number of patients received a maximum lens dose of 15 Gy; in this group the actuarial incidence of lens opacities at 8 years was 57% with visual impairment in 38%. The adult lens can tolerate a total dose of 5 Gy during a fractionated course of supervoltage radiation therapy without showing any changes. Doses of 16.5 Gy or higher will almost invariably lead to visual impairment. The dose which causes a 50% probability of visual impairment is approximately 15 Gy. 10 refs., 4 figs., 1 tab.

  1. Some cosmic radiation dose measurements aboard flights connecting Zagreb Airport.

    PubMed

    Vuković, B; Radolić, V; Lisjak, I; Vekić, B; Poje, M; Planinić, J

    2008-02-01

    When primary particles from space, mainly protons, enter the atmosphere, they produce interactions with air nuclei, and cosmic-ray showers are induced. The radiation field at aircraft altitude is complex, with different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. The non-neutron component of cosmic radiation dose aboard A320 and ATR40 aircraft was measured with TLD-100 (LiF:Mg,Ti) detectors and the Mini 6100 semiconductor dosimeter; the neutron dose was measured with the neutron dosimeter consisted of LR-115 track detector and boron foil BN-1 or 10B converter. The estimated occupational effective dose for the aircraft crew (A320) working 500 h per year was 1.64 mSv. Another experiment was performed at the flights Zagreb-Paris-Buenos Aires and reversely, when one measured non-neutron cosmic radiation dose; for 26.7 h of flight, the MINI 6100 dosimeter gave an average dose rate of 2.3 microSv/h and the TLD dosimeter registered the dose equivalent of 75 microSv or the average dose rate of 2.7 microSv/h; the neutron dosimeter gave the dose rate of 2.4 microSv/h. In the same month, February 2005, a traveling to Japan (24-h-flight: Zagreb-Frankfurt-Tokyo and reversely) and the TLD-100 measurement showed the average dose rate of 2.4microSv/h; the neutron dosimeter gave the dose rate of 2.5 microSv/h. Comparing dose rates of the non-neutron component (low LET) and the neutron one (high LET) of the radiation field at the aircraft flight level, we could conclude that the neutron component carried about 50% of the total dose, that was near other known data.

  2. Maximum likelihood estimation for cytogenetic dose-response curves

    SciTech Connect

    Frome, E.L; DuFrain, R.J.

    1983-10-01

    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(..gamma..d + g(t, tau)d/sup 2/), where t is the time and d is dose. The coefficient of the d/sup 2/ 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. Radiation dose and radiation protection principle awareness: a survey among Nigerian paediatricians.

    PubMed

    Famurewa, O C; Obiajunwa, P O; Elusiyan, J B; Ibitoye, B O

    2014-03-01

    This study is aimed at determining the knowledge of Paediatricians in Nigeria about the basic principle of radiation protection ALARA (As Low As Reasonably Achievable) and their knowledge of the radiation doses that children receive during some common radiological procedures. Two hundred and fifty questionnaires were circulated among paediatricians at the 2012 annual Paediatricians' Association of Nigeria Conference. The questionnaires contain 10 questions designed to asses the pediatricians' general knowledge on : ionising radiation and the risks, doses children receive during some common radiological procedures and awareness of the radiation protection principle, ALARA ( As Low As Reasonably Achievable). Of the 162 Paediatricians that participated, 69% named at least one non medical source of ionising radiation, 54.9% would not recommend CXR to screen an apparently healthy child for tuberculosis and 87% believe that children are at greater risk of adverse effects of ionising radiation. For dose estimation, 51.9% and 51.2% of the paediatricians underestimated doses received during Cranial and abdominal computerised tomography respectively while 13.6% and 37% respectively erroneously believed that abdominal ultrasound and brain magnetic resonance imaging utilise ionising radiation. 13.6% gave the correct meaning of the Acronym ALARA. The Paediatricians' knowledge about the basic principle of radiation protection ALARA and the doses that children receive during some common radiological procedures is poor. There is need to ensure adequate training on radiation hazards and protection at all levels of medical education.

  4. Review and evaluation of principles used in the estimation of radiation doses associated with the practice of deepsea disposal of low-level radioactive waste

    SciTech Connect

    Baker, D.A.; Templeton, W.L.; Soldat, J.K.

    1985-09-01

    The relevant national and international guidance concerning the estimation of radiological doses from the practice of deepsea disposal of radioactive waste was reviewed. The review includes the dose limitation guidance of the various national and international bodies, especially that of the International Commission on Radiological Protection (ICRP). Pathway modeling is discussed as well as the oceanographic models of the International Atomic Energy Agency (IAEA). Included in the discussion are the recommendations for the definition of high-level waste by the IAEA for use by the London Dumping Convention (LDC) in setting limits for ocean disposal of waste. An assessment of the ICRP's radiological protection system using the effective whole-body dose methodology is made. Present models, which should continue to be improved as the research data becomes available, do provide an adequate basis for regulatory authorities to decide whether authorization for a proposed disposal can be granted, since they provide a means of indicating whether maximum individual (critical groups) exposure limits are likely to be exceeded. However, new models and information are continuously being developed by the international community to assess ocean disposal of radioactive waste in comparison to land disposal and to compare one site against another. 47 refs., 2 figs., 4 tabs.

  5. Radiation doses from Hanford site releases to the atmosphere

    SciTech Connect

    Farris, W.T.; Napier, B.A.; Ikenberry, T.A.

    1994-06-01

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

  6. Estimating the Risks of Breast Cancer Radiotherapy: Evidence From Modern Radiation Doses to the Lungs and Heart and From Previous Randomized Trials.

    PubMed

    Taylor, Carolyn; Correa, Candace; Duane, Frances K; Aznar, Marianne C; Anderson, Stewart J; Bergh, Jonas; Dodwell, David; Ewertz, Marianne; Gray, Richard; Jagsi, Reshma; Pierce, Lori; Pritchard, Kathleen I; Swain, Sandra; Wang, Zhe; Wang, Yaochen; Whelan, Tim; Peto, Richard; McGale, Paul

    2017-05-20

    Purpose Radiotherapy reduces the absolute risk of breast cancer mortality by a few percentage points in suitable women but can cause a second cancer or heart disease decades later. We estimated the absolute long-term risks of modern breast cancer radiotherapy. Methods First, a systematic literature review was performed of lung and heart doses in breast cancer regimens published during 2010 to 2015. Second, individual patient data meta-analyses of 40,781 women randomly assigned to breast cancer radiotherapy versus no radiotherapy in 75 trials yielded rate ratios (RRs) for second primary cancers and cause-specific mortality and excess RRs (ERRs) per Gy for incident lung cancer and cardiac mortality. Smoking status was unavailable. Third, the lung or heart ERRs per Gy in the trials and the 2010 to 2015 doses were combined and applied to current smoker and nonsmoker lung cancer and cardiac mortality rates in population-based data. Results Average doses from 647 regimens published during 2010 to 2015 were 5.7 Gy for whole lung and 4.4 Gy for whole heart. The median year of irradiation was 2010 (interquartile range [IQR], 2008 to 2011). Meta-analyses yielded lung cancer incidence ≥ 10 years after radiotherapy RR of 2.10 (95% CI, 1.48 to 2.98; P < .001) on the basis of 134 cancers, indicating 0.11 (95% CI, 0.05 to 0.20) ERR per Gy whole-lung dose. For cardiac mortality, RR was 1.30 (95% CI, 1.15 to 1.46; P < .001) on the basis of 1,253 cardiac deaths. Detailed analyses indicated 0.04 (95% CI, 0.02 to 0.06) ERR per Gy whole-heart dose. Estimated absolute risks from modern radiotherapy were as follows: lung cancer, approximately 4% for long-term continuing smokers and 0.3% for nonsmokers; and cardiac mortality, approximately 1% for smokers and 0.3% for nonsmokers. Conclusion For long-term smokers, the absolute risks of modern radiotherapy may outweigh the benefits, yet for most nonsmokers (and ex-smokers), the benefits of radiotherapy far outweigh the risks. Hence

  7. Estimating the Risks of Breast Cancer Radiotherapy: Evidence From Modern Radiation Doses to the Lungs and Heart and From Previous Randomized Trials

    PubMed Central

    Taylor, Carolyn; Correa, Candace; Duane, Frances K.; Aznar, Marianne C.; Anderson, Stewart J.; Bergh, Jonas; Dodwell, David; Ewertz, Marianne; Gray, Richard; Jagsi, Reshma; Pierce, Lori; Pritchard, Kathleen I.; Swain, Sandra; Wang, Zhe; Wang, Yaochen; Whelan, Tim; Peto, Richard; McGale, Paul

    2017-01-01

    Purpose Radiotherapy reduces the absolute risk of breast cancer mortality by a few percentage points in suitable women but can cause a second cancer or heart disease decades later. We estimated the absolute long-term risks of modern breast cancer radiotherapy. Methods First, a systematic literature review was performed of lung and heart doses in breast cancer regimens published during 2010 to 2015. Second, individual patient data meta-analyses of 40,781 women randomly assigned to breast cancer radiotherapy versus no radiotherapy in 75 trials yielded rate ratios (RRs) for second primary cancers and cause-specific mortality and excess RRs (ERRs) per Gy for incident lung cancer and cardiac mortality. Smoking status was unavailable. Third, the lung or heart ERRs per Gy in the trials and the 2010 to 2015 doses were combined and applied to current smoker and nonsmoker lung cancer and cardiac mortality rates in population-based data. Results Average doses from 647 regimens published during 2010 to 2015 were 5.7 Gy for whole lung and 4.4 Gy for whole heart. The median year of irradiation was 2010 (interquartile range [IQR], 2008 to 2011). Meta-analyses yielded lung cancer incidence ≥ 10 years after radiotherapy RR of 2.10 (95% CI, 1.48 to 2.98; P < .001) on the basis of 134 cancers, indicating 0.11 (95% CI, 0.05 to 0.20) ERR per Gy whole-lung dose. For cardiac mortality, RR was 1.30 (95% CI, 1.15 to 1.46; P < .001) on the basis of 1,253 cardiac deaths. Detailed analyses indicated 0.04 (95% CI, 0.02 to 0.06) ERR per Gy whole-heart dose. Estimated absolute risks from modern radiotherapy were as follows: lung cancer, approximately 4% for long-term continuing smokers and 0.3% for nonsmokers; and cardiac mortality, approximately 1% for smokers and 0.3% for nonsmokers. Conclusion For long-term smokers, the absolute risks of modern radiotherapy may outweigh the benefits, yet for most nonsmokers (and ex-smokers), the benefits of radiotherapy far outweigh the risks. Hence

  8. Epigenomic Adaptation to Low Dose Radiation

    SciTech Connect

    Gould, Michael N.

    2015-06-30

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

  9. Imaging of Radiation Dose for Stereotactic Radiosurgery

    SciTech Connect

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

    2015-01-15

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

  10. Radiation-induced genomic instability: radiation quality and dose response

    NASA Technical Reports Server (NTRS)

    Smith, Leslie E.; Nagar, Shruti; Kim, Grace J.; Morgan, William F.

    2003-01-01

    Genomic instability is a term used to describe a phenomenon that results in the accumulation of multiple changes required to convert a stable genome of a normal cell to an unstable genome characteristic of a tumor. There has been considerable recent debate concerning the importance of genomic instability in human cancer and its temporal occurrence in the carcinogenic process. Radiation is capable of inducing genomic instability in mammalian cells and instability is thought to be the driving force responsible for radiation carcinogenesis. Genomic instability is characterized by a large collection of diverse endpoints that include large-scale chromosomal rearrangements and aberrations, amplification of genetic material, aneuploidy, micronucleus formation, microsatellite instability, and gene mutation. The capacity of radiation to induce genomic instability depends to a large extent on radiation quality or linear energy transfer (LET) and dose. There appears to be a low dose threshold effect with low LET, beyond which no additional genomic instability is induced. Low doses of both high and low LET radiation are capable of inducing this phenomenon. This report reviews data concerning dose rate effects of high and low LET radiation and their capacity to induce genomic instability assayed by chromosomal aberrations, delayed lethal mutations, micronuclei and apoptosis.

  11. Radiation-induced genomic instability: radiation quality and dose response

    NASA Technical Reports Server (NTRS)

    Smith, Leslie E.; Nagar, Shruti; Kim, Grace J.; Morgan, William F.

    2003-01-01

    Genomic instability is a term used to describe a phenomenon that results in the accumulation of multiple changes required to convert a stable genome of a normal cell to an unstable genome characteristic of a tumor. There has been considerable recent debate concerning the importance of genomic instability in human cancer and its temporal occurrence in the carcinogenic process. Radiation is capable of inducing genomic instability in mammalian cells and instability is thought to be the driving force responsible for radiation carcinogenesis. Genomic instability is characterized by a large collection of diverse endpoints that include large-scale chromosomal rearrangements and aberrations, amplification of genetic material, aneuploidy, micronucleus formation, microsatellite instability, and gene mutation. The capacity of radiation to induce genomic instability depends to a large extent on radiation quality or linear energy transfer (LET) and dose. There appears to be a low dose threshold effect with low LET, beyond which no additional genomic instability is induced. Low doses of both high and low LET radiation are capable of inducing this phenomenon. This report reviews data concerning dose rate effects of high and low LET radiation and their capacity to induce genomic instability assayed by chromosomal aberrations, delayed lethal mutations, micronuclei and apoptosis.

  12. Radiation dose in temporomandibular joint zonography

    SciTech Connect

    Coucke, M.E.; Bourgoignie, R.R.; Dermaut, L.R.; Bourgoignie, K.A.; Jacobs, R.J. )

    1991-06-01

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

  13. Collective dose-practical ways to estimate a dose matrix.

    PubMed

    Simmonds, Jane; Sihra, Kamaljit; Bexon, Antony

    2006-06-01

    It has been suggested that collective doses should be presented in the form of a 'dose matrix' giving information on the breakdown of collective dose in space and time and by population group. This paper is an initial attempt to provide such a breakdown by geographic region and time, and to give an idea of associated individual doses for routine discharges to atmosphere. This is done through the use of representative per-caput individual doses but these need to be supplemented by information on the individual doses received by the critical group for a full radiological impact assessment. The results show that it is important to distinguish between the different population groups for up to a few hundred years following the discharge. However, beyond this time the main contribution is from global circulation and this distinction is less important. The majority of the collective dose was found to be delivered at low levels of individual doses; the estimated per-caput dose rates were significantly less than 10(-5) Sv y(-1), a level of dose felt to give rise to a trivial risk to the exposed individual.

  14. Radiation Doses and Associated Risk From the Fukushima Nuclear Accident.

    PubMed

    Ishikawa, Tetsuo

    2017-03-01

    The magnitude of dose due to the Fukushima Daiichi Accident was estimated by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2013 report published in April 2014. Following this, the UNSCEAR white paper, which comprises a digest of new information for the 2013 Fukushima report, was published in October 2015. Another comprehensive report on radiation dose due to the accident is the International Atomic Energy Agency (IAEA) report on the Fukushima Daiichi Accident published in August 2015. Although the UNSCEAR and IAEA publications well summarize doses received by residents, they review only literature published before the end of December 2014 and the end of March 2015, respectively. However, some studies on dose estimation have been published since then. In addition, the UNSCEAR 2013 report states it was likely that some overestimation had been introduced generally by the methodology used by the Committee. For example, effects of decontamination were not considered in the lifetime external dose estimated. Decontamination is in progress for most living areas in Fukushima Prefecture, which could reduce long-term external dose to residents. This article mainly reviews recent English language articles that may add new information to the UNSCEAR and IAEA publications. Generally, recent articles suggest lower doses than those presented by the UNSCEAR 2013 report.

  15. Radiation Leukemogenesis at Low Dose Rates

    SciTech Connect

    Weil, Michael; Ullrich, Robert

    2013-09-25

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

  16. Dosimeter for measuring skin dose and more deeply penetrating radiation

    DOEpatents

    Jones, Donald E.; Parker, DeRay; Boren, Paul R.

    1981-01-01

    A personnel dosimeter includes a plurality of compartments containing thermoluminescent dosimeter phosphors for registering radiation dose absorbed in the wearer's sensitive skin layer and for registering more deeply penetrating radiation. Two of the phosphor compartments communicate with thin windows of different thicknesses to obtain a ratio of shallowly penetrating radiation, e.g. beta. A third phosphor is disposed within a compartment communicating with a window of substantially greater thickness than the windows of the first two compartments for estimating the more deeply penetrating radiation dose. By selecting certain phosphors that are insensitive to neutrons and by loading the holder material with netruon-absorbing elements, energetic neutron dose can be estimated separately from other radiation dose. This invention also involves a method of injection molding of dosimeter holders with thin windows of consistent thickness at the corresponding compartments of different holders. This is achieved through use of a die insert having the thin window of precision thickness in place prior to the injection molding step.

  17. Perchlorate exposure and dose estimates in infants

    PubMed Central

    Valentín-Blasini, Liza; Blount, Benjamin C.; Otero-Santos, Samaret; Cao, Yang; Bernbaum, Judy C.; Rogan, Walter J.

    2011-01-01

    Perchlorate is a naturally occurring inorganic anion used as a component of solid rocket fuel, explosives, and pyrotechnics. Sufficiently high perchlorate intakes can modify thyroid function by competitively inhibiting iodide uptake in adults; however little is known about perchlorate exposure and health effects in infants. Food intake models predict that infants have higher perchlorate exposure doses than adults. For this reason, we measured perchlorate and related anions (nitrate, thiocyanate, and iodide) in 206 urine samples from 92 infants ages 1–377 days and calculated perchlorate intake dose for this population of infants. The median estimated exposure dose for this population of infants was 0.160 μg/kg/day. Of the 205 individual dose estimates, 9% exceeded the reference dose of 0.7 μg/kg/day; 6% of infants providing multiple samples had multiple perchlorate dose estimates above the reference dose. Estimated exposure dose differed by feeding method: breast-fed infants had a higher perchlorate exposure dose (geometric mean 0.220 μg/kg/day) than infants consuming cow milk-based formula (geometric mean 0.103 μg/kg/day, p<0.0001) or soy-based formula (geometric mean 0.027 μg/kg/day, p<0.0001), consistent with dose estimates based on dietary intake data. The ability of perchlorate to block adequate iodide uptake by the thyroid may have been reduced by the iodine-sufficient status of the infants studied (median urinary iodide 125 μg/L). Further research is needed to see whether these perchlorate intake doses lead to any health effects. PMID:21449579

  18. Perchlorate exposure and dose estimates in infants.

    PubMed

    Valentín-Blasini, Liza; Blount, Benjamin C; Otero-Santos, Samaret; Cao, Yang; Bernbaum, Judy C; Rogan, Walter J

    2011-05-01

    Perchlorate is a naturally occurring inorganic anion used as a component of solid rocket fuel, explosives, and pyrotechnics. Sufficiently high perchlorate intakes can modify thyroid function by competitively inhibiting iodide uptake in adults; however, little is known about perchlorate exposure and health effects in infants. Food intake models predict that infants have higher perchlorate exposure doses than adults. For this reason, we measured perchlorate and related anions (nitrate, thiocyanate, and iodide) in 206 urine samples from 92 infants ages 1-377 days and calculated perchlorate intake dose for this sample of infants. The median estimated exposure dose for this sample of infants was 0.160 μg/kg/day. Of the 205 individual dose estimates, 9% exceeded the reference dose of 0.7 μg/kg/day; 6% of infants providing multiple samples had multiple perchlorate dose estimates above the reference dose. Estimated exposure dose differed by feeding method: breast-fed infants had a higher perchlorate exposure dose (geometric mean 0.220 μg/kg/day) than infants consuming cow milk-based formula (geometric mean 0.103 μg/kg/day, p < 0.0001) or soy-based formula (geometric mean 0.027 μg/kg/day, p < 0.0001), consistent with dose estimates based on dietary intake data. The ability of perchlorate to block adequate iodide uptake by the thyroid may have been reduced by the iodine-sufficient status of the infants studied (median urinary iodide 125 μg/L). Further research is needed to see whether these perchlorate intake doses lead to any health effects.

  19. Fetal dose estimates for CT pelvimetry

    SciTech Connect

    Moore, M.M.; Shearer, D.R.

    1989-04-01

    Fetal and maternal dose estimates for computed tomographic pelvimetry have been obtained from phantom measurements. Use of routine abdomen imaging techniques may result in localized fetal doses in excess of 13 mGy (1.3 rad). With the use of a low-exposure (40-mAs) technique, it is possible to obtain images of acceptable quality for the necessary measurements. The resulting dose to the fetus is approximately 2.3 mGy (0.23 rad).

  20. Nonparametric Bayesian methods for benchmark dose estimation.

    PubMed

    Guha, Nilabja; Roy, Anindya; Kopylev, Leonid; Fox, John; Spassova, Maria; White, Paul

    2013-09-01

    The article proposes and investigates the performance of two Bayesian nonparametric estimation procedures in the context of benchmark dose estimation in toxicological animal experiments. The methodology is illustrated using several existing animal dose-response data sets and is compared with traditional parametric methods available in standard benchmark dose estimation software (BMDS), as well as with a published model-averaging approach and a frequentist nonparametric approach. These comparisons together with simulation studies suggest that the nonparametric methods provide a lot of flexibility in terms of model fit and can be a very useful tool in benchmark dose estimation studies, especially when standard parametric models fail to fit to the data adequately. © 2013 Society for Risk Analysis.

  1. radir package: an R implementation for cytogenetic biodosimetry dose estimation.

    PubMed

    Moriña, David; Higueras, Manuel; Puig, Pedro; Ainsbury, Elizabeth A; Rothkamm, Kai

    2015-09-01

    The Bayesian framework has been shown to be very useful in cytogenetic dose estimation. This approach allows description of the probability of an event in terms of previous knowledge, e.g. its expectation and/or its uncertainty. A new R package entitled radir (radiation inverse regression) has been implemented with the aim of reproducing a recent Bayesian-type dose estimation methodology. radir adopts the method of dose estimation under the Poisson assumption of the responses (the chromosomal aberrations counts) for the required dose-response curve (typically linear or quadratic). The individual commands are described in detail and relevant examples of the use of the methods and the corresponding radir software tools are given. The suitability of this methodology is highlighted and its application encouraged by providing a user-friendly command-type software interface within the R statistical software (version 3.1.1 or higher), which includes a complete manual.

  2. Radiation Dose Testing on Juno High Voltage Cables

    NASA Technical Reports Server (NTRS)

    Green, Nelson W.; Kirkham, Harold; Kim, Wousik; McAlpine, Bill

    2008-01-01

    The Juno mission to Jupiter will have a highly elliptical orbit taking the spacecraft through the radiation belts surrounding the planet. During these passes through the radiation belts, the spacecraft will be subject to high doses of radiation from energetic electrons and protons with energies ranging from 10 keV to 1 GeV. While shielding within the spacecraft main body will reduce the total absorbed dose to much of the spacecraft electronics, instruments and cables on the outside of the spacecraft will receive much higher levels of absorbed dose. In order to estimate the amount of degradation to two such cables, testing has been performed on two coaxial cables intended to provide high voltages to three of the instruments on Juno. Both cables were placed in a vacuum of 5x10-6 torr and cooled to -50 C prior to exposure to the radiation sources. Measurements of the coaxial capacitance per unit length and partial discharge noise floor indicate that increasing levels of radiation make measurable but acceptably small changes to the F EP Teflon utilized in the construction of these cables. In addition to the radiation dose testing, observations were made on the internal electrostatic charging characteristics of these cables and multiple discharges were recorded.

  3. Radiation Dose Testing on Juno High Voltage Cables

    NASA Technical Reports Server (NTRS)

    Green, Nelson W.; Kirkham, Harold; Kim, Wousik; McAlpine, Bill

    2008-01-01

    The Juno mission to Jupiter will have a highly elliptical orbit taking the spacecraft through the radiation belts surrounding the planet. During these passes through the radiation belts, the spacecraft will be subject to high doses of radiation from energetic electrons and protons with energies ranging from 10 keV to 1 GeV. While shielding within the spacecraft main body will reduce the total absorbed dose to much of the spacecraft electronics, instruments and cables on the outside of the spacecraft will receive much higher levels of absorbed dose. In order to estimate the amount of degradation to two such cables, testing has been performed on two coaxial cables intended to provide high voltages to three of the instruments on Juno. Both cables were placed in a vacuum of 5x10(exp -6) torr and cooled to -50(deg)C prior to exposure to the radiation sources. Measurements of the coaxial capacitance per unit length and partial discharge noise floor indicate that increasing levels of radiation make measurable but acceptably small changes to the F EP Teflon utilized in the construction of these cables. In addition to the radiation dose testing, observations were made on the internal electrostatic charging characteristics of these cables and multiple discharges were recorded.

  4. The effect of anatomical modeling on space radiation dose estimates: a comparison of doses for NASA phantoms and the 5th, 50th, and 95th percentile male and female astronauts

    NASA Astrophysics Data System (ADS)

    Bahadori, Amir A.; Van Baalen, Mary; Shavers, Mark R.; Dodge, Charles; Semones, Edward J.; Bolch, Wesley E.

    2011-03-01

    The National Aeronautics and Space Administration (NASA) performs organ dosimetry and risk assessment for astronauts using model-normalized measurements of the radiation fields encountered in space. To determine the radiation fields in an organ or tissue of interest, particle transport calculations are performed using self-shielding distributions generated with the computer program CAMERA to represent the human body. CAMERA mathematically traces linear rays (or path lengths) through the computerized anatomical man (CAM) phantom, a computational stylized model developed in the early 1970s with organ and body profiles modeled using solid shapes and scaled to represent the body morphometry of the 1950 50th percentile (PCTL) Air Force male. With the increasing use of voxel phantoms in medical and health physics, a conversion from a mathematical-based to a voxel-based ray-tracing algorithm is warranted. In this study, the voxel-based ray tracer (VoBRaT) is introduced to ray trace voxel phantoms using a modified version of the algorithm first proposed by Siddon (1985 Med. Phys. 12 252-5). After validation, VoBRAT is used to evaluate variations in body self-shielding distributions for NASA phantoms and six University of Florida (UF) hybrid phantoms, scaled to represent the 5th, 50th, and 95th PCTL male and female astronaut body morphometries, which have changed considerably since the inception of CAM. These body self-shielding distributions are used to generate organ dose equivalents and effective doses for five commonly evaluated space radiation environments. It is found that dosimetric differences among the phantoms are greatest for soft radiation spectra and light vehicular shielding.

  5. The effect of anatomical modeling on space radiation dose estimates: a comparison of doses for NASA phantoms and the 5th, 50th, and 95th percentile male and female astronauts.

    PubMed

    Bahadori, Amir A; Van Baalen, Mary; Shavers, Mark R; Dodge, Charles; Semones, Edward J; Bolch, Wesley E

    2011-03-21

    The National Aeronautics and Space Administration (NASA) performs organ dosimetry and risk assessment for astronauts using model-normalized measurements of the radiation fields encountered in space. To determine the radiation fields in an organ or tissue of interest, particle transport calculations are performed using self-shielding distributions generated with the computer program CAMERA to represent the human body. CAMERA mathematically traces linear rays (or path lengths) through the computerized anatomical man (CAM) phantom, a computational stylized model developed in the early 1970s with organ and body profiles modeled using solid shapes and scaled to represent the body morphometry of the 1950 50th percentile (PCTL) Air Force male. With the increasing use of voxel phantoms in medical and health physics, a conversion from a mathematical-based to a voxel-based ray-tracing algorithm is warranted. In this study, the voxel-based ray tracer (VoBRaT) is introduced to ray trace voxel phantoms using a modified version of the algorithm first proposed by Siddon (1985 Med. Phys. 12 252-5). After validation, VoBRAT is used to evaluate variations in body self-shielding distributions for NASA phantoms and six University of Florida (UF) hybrid phantoms, scaled to represent the 5th, 50th, and 95th PCTL male and female astronaut body morphometries, which have changed considerably since the inception of CAM. These body self-shielding distributions are used to generate organ dose equivalents and effective doses for five commonly evaluated space radiation environments. It is found that dosimetric differences among the phantoms are greatest for soft radiation spectra and light vehicular shielding.

  6. beta- and gamma-Comparative dose estimates on Enewetak Atoll.

    PubMed

    Crase, K W; Gudiksen, P H; Robison, W L

    1982-05-01

    Enewetak Atoll is one of the Pacific atolls used for atmospheric testing of U.S. nuclear weapons. Beta dose and gamma-ray exposure measurements were made on two islands of the Enewetak Atoll during July-August 1976 to determine the beta and low energy gamma-contribution to the total external radiation doses to the returning Marshallese. Measurements were made at numerous locations with thermoluminescent dosimeters (TLD), pressurized ionization chambers, portable NaI detectors, and thin-window pancake GM probes. Results of the TLD measurements with and without a beta-attenuator indicate that approx. 29% of the total dose rate at 1 m in air is due to beta- or low energy gamma-contribution. The contribution at any particular site, however, is somewhat dependent on ground cover, since a minimal amount of vegetation will reduce it significantly from that over bare soil, but thick stands of vegetation have little effect on any further reductions. Integral 30-yr external shallow dose estimates for future inhabitants were made and compared with external dose estimates of a previous large scale radiological survey (En73). Integral 30-yr shallow external dose estimates are 25-50% higher than whole body estimates. Due to the low penetrating ability of the beta's or low energy gamma's, however, several remedial actions can be taken to reduce the shallow dose contribution to the total external dose.

  7. The development of a decision support system with an interactive clinical user interface for estimating treatment parameters in radiation therapy in order to reduce radiation dose in head and neck patients

    NASA Astrophysics Data System (ADS)

    Verma, Sneha; Liu, Joseph; Deshpande, Ruchi; DeMarco, John; Liu, Brent J.

    2017-03-01

    The primary goal in radiation therapy is to target the tumor with the maximum possible radiation dose while limiting the radiation exposure of the surrounding healthy tissues. However, in order to achieve an optimized treatment plan, many constraints, such as gender, age, tumor type, location, etc. need to be considered. The location of the malignant tumor with respect to the vital organs is another possible important factor for treatment planning process which can be quantified as a feature making it easier to analyze its effects. Incorporation of such features into the patient's medical history could provide additional knowledge that could lead to better treatment outcomes. To show the value of features such as relative locations of tumors and surrounding organs, the data is first processed in order to calculate the features and formulate a feature matrix. Then these feature are matched with retrospective cases with similar features to provide the clinician with insight on delivered dose in similar cases from past. This process provides a range of doses that can be delivered to the patient while limiting the radiation exposure of surrounding organs based on similar retrospective cases. As the number of patients increase, there will be an increase in computations needed for feature extraction as well as an increase in the workload for the physician to find the perfect dose amount. In order to show how such algorithms can be integrated we designed and developed a system with a streamlined workflow and interface as prototype for the clinician to test and explore. Integration of the tumor location feature with the clinician's experience and training could play a vital role in designing new treatment algorithms and better outcomes. Last year, we presented how multi-institutional data into a decision support system is incorporated. This year the presentation is focused on the interface and demonstration of the working prototype of informatics system.

  8. Low-dose radiation and leukemia

    SciTech Connect

    Linos, A.; Gray, J.E.; Orvis, A.L.; Kyle, R.A.; O'Fallon, W.M.; Kurland, L.T.

    1980-05-15

    We investigated the effect of diagnostic and low-level therapeutic radiation (less than 300 rads to bone marrow) on the development of leukemia. During this study, 138 patients with leukemia (representing all known incidence cases of leukemia in residents of Olmsted County, Minnesota, between 1955 and 1974) were each matched with two controls, and the lifelong experiences of both groups with regard to diagnostic and therapeutic radiation were ascertained. No statistically significant increase was found in the risk of developing leukemia after radiation doses of 0 to 300 rads (3 Gy) to the bone marrow when these amounts were administered in small doses over long periods of time, as in routine medical care.

  9. Space radiation absorbed dose distribution in a human phantom

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

  10. Space radiation absorbed dose distribution in a human phantom

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

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

    PubMed

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

    2002-01-01

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

  12. Estimation of food consumption. Hanford Environmental Dose Reconstruction Project

    SciTech Connect

    Callaway, J.M. Jr.

    1992-04-01

    The research reported in this document was conducted as a part of the Hanford Environmental Dose Reconstruction (HEDR) Project. The objective of the HEDR Project is to estimate the radiation doses that people could have received from operations at the Hanford Site. Information required to estimate these doses includes estimates of the amounts of potentially contaminated foods that individuals in the region consumed during the study period. In that general framework, the objective of the Food Consumption Task was to develop a capability to provide information about the parameters of the distribution(s) of daily food consumption for representative groups in the population for selected years during the study period. This report describes the methods and data used to estimate food consumption and presents the results developed for Phase I of the HEDR Project.

  13. AAPM/RSNA Physics Tutorial for Residents: Topics in CT. Radiation dose in CT.

    PubMed

    McNitt-Gray, Michael F

    2002-01-01

    This article describes basic radiation dose concepts as well as those specifically developed to describe the radiation dose from computed tomography (CT). Basic concepts of radiation dose are reviewed, including exposure, absorbed dose, and effective dose. Radiation dose from CT demonstrates variations within the scan plane and along the z axis because of its unique geometry and usage. Several CT-specific dose descriptors have been developed: the Multiple Scan Average Dose descriptor, the Computed Tomography Dose Index (CTDI) and its variations (CTDI(100), CTDI(w), CTDI(vol)), and the dose-length product. Factors that affect radiation dose from CT include the beam energy, tube current-time product, pitch, collimation, patient size, and dose reduction options. Methods of reducing the radiation dose to a patient from CT include reducing the milliampere-seconds value, increasing the pitch, varying the milliampere-seconds value according to patient size, and reducing the beam energy. The effective dose from CT can be estimated by using Monte Carlo methods to simulate CT of a mathematical patient model, by estimating the energy imparted to the body region being scanned, or by using conversion factors for general anatomic regions. Issues related to radiation dose from CT are being addressed by the Society for Pediatric Radiology, the American Association of Physicists in Medicine, the American College of Radiology, and the Center for Devices and Radiological Health of the Food and Drug Administration.

  14. 10 CFR 20.1004 - Units of radiation dose.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Units of radiation dose. 20.1004 Section 20.1004 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION General Provisions § 20.1004 Units of radiation dose. (a) Definitions. As used in this part, the units of radiation dose are:...

  15. 10 CFR 20.1004 - Units of radiation dose.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Units of radiation dose. 20.1004 Section 20.1004 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION General Provisions § 20.1004 Units of radiation dose. (a) Definitions. As used in this part, the units of radiation dose are:...

  16. 10 CFR 20.1004 - Units of radiation dose.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Units of radiation dose. 20.1004 Section 20.1004 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION General Provisions § 20.1004 Units of radiation dose. (a) Definitions. As used in this part, the units of radiation dose are: Gray...

  17. 10 CFR 20.1004 - Units of radiation dose.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Units of radiation dose. 20.1004 Section 20.1004 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION General Provisions § 20.1004 Units of radiation dose. (a) Definitions. As used in this part, the units of radiation dose are: Gray...

  18. 10 CFR 20.1004 - Units of radiation dose.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Units of radiation dose. 20.1004 Section 20.1004 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION General Provisions § 20.1004 Units of radiation dose. (a) Definitions. As used in this part, the units of radiation dose are: Gray...

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

    PubMed

    Markou, Pavlos

    2007-01-01

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

  20. 78 FR 53147 - Subcommittee for Dose Reconstruction Reviews (SDRR), Advisory Board on Radiation and Worker...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-28

    ... (SDRR), Advisory Board on Radiation and Worker Health (ABRWH or the Advisory Board), National Institute... employees at any Department of Energy facility who were exposed to radiation but for whom it is not feasible to estimate their radiation dose, and on whether there is reasonable likelihood that such radiation...

  1. Estimation of radon exhalation rate, natural radioactivity and radiation doses in fly ash samples from Durgapur thermal power plant, West Bengal, India.

    PubMed

    Mahur, A K; Kumar, Rajesh; Sengupta, D; Prasad, Rajendra

    2008-08-01

    Coal and its by products often contain significant amounts of radionuclides, including uranium which is the ultimate source of the radioactive gas radon. Burning of coal and the subsequent emission to the atmosphere cause the re-distribution of toxic trace elements in the environment. Due to considerable economic and environmental importance and diverse uses, the collected fly ash has become a subject of worldwide interest in recent years. In the present study, radon exhalation rate and the activity concentration of (238)U, (232)Th and (40)K radionuclides in fly ash samples from Durgapur thermal power plant (WB) have been measured by "Sealed Can technique" using LR-115 type II detectors and a low level NaI (Tl) based gamma ray spectrometer, respectively. Radon exhalation rate varied from 360.0 to 470.0 mBq m(-2)h(-1) with an average value of 406.8 mBq m(-2)h(-1). Activity concentrations of (238)U ranged from 84.8 to 126.4 Bq kg(-1) with an average value of 99.3Bqkg(-1), (232)Th ranged from 98.1 to 140.5 Bq kg(-1) with an average value of 112.9 Bq kg(-1) and (40)K ranged from 267.1 to 364.9 Bq kg(-1) with an average value of 308.9 Bq kg(-1). Radium equivalent activity obtained from activity concentrations is found to vary from 256.5 to 352.8 Bq kg(-1) with an average value of 282.5 Bq kg(-1). Absorbed gamma dose rates due to the presence of (238)U, (232)Th and (40)K in fly ash samples vary in the range 115.3-158.5 nGy h(-1) with an average value of 126.4 nGy h(-1). While the external annual effective dose rate varies from 0.14 to 0.19 mSv y(-1) with an average value of 0.15 mSv y(-1), effective dose equivalent estimated from exhalation rate varies from 42.5 to 55.2 microSv y(-1) with an average value of 47.8 microSv y(-1). Values of external hazard index H(ex) for the fly ash samples studied in this work range from 0.69 to 0.96 with a mean value of 0.77.

  2. Bayesian dose-response analysis for epidemiological studies with complex uncertainty in dose estimation.

    PubMed

    Kwon, Deukwoo; Hoffman, F Owen; Moroz, Brian E; Simon, Steven L

    2016-02-10

    Most conventional risk analysis methods rely on a single best estimate of exposure per person, which does not allow for adjustment for exposure-related uncertainty. Here, we propose a Bayesian model averaging method to properly quantify the relationship between radiation dose and disease outcomes by accounting for shared and unshared uncertainty in estimated dose. Our Bayesian risk analysis method utilizes multiple realizations of sets (vectors) of doses generated by a two-dimensional Monte Carlo simulation method that properly separates shared and unshared errors in dose estimation. The exposure model used in this work is taken from a study of the risk of thyroid nodules among a cohort of 2376 subjects who were exposed to fallout from nuclear testing in Kazakhstan. We assessed the performance of our method through an extensive series of simulations and comparisons against conventional regression risk analysis methods. When the estimated doses contain relatively small amounts of uncertainty, the Bayesian method using multiple a priori plausible draws of dose vectors gave similar results to the conventional regression-based methods of dose-response analysis. However, when large and complex mixtures of shared and unshared uncertainties are present, the Bayesian method using multiple dose vectors had significantly lower relative bias than conventional regression-based risk analysis methods and better coverage, that is, a markedly increased capability to include the true risk coefficient within the 95% credible interval of the Bayesian-based risk estimate. An evaluation of the dose-response using our method is presented for an epidemiological study of thyroid disease following radiation exposure.

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

    SciTech Connect

    Prezado, Y.; Fois, G.; Edouard, M.; Nemoz, C.; Renier, M.; Requardt, H.; Esteve, F.; Adam, JF.; Elleaume, H.; Bravin, A.

    2009-03-15

    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.

  4. Dose-volume histogram prediction using density estimation.

    PubMed

    Skarpman Munter, Johanna; Sjölund, Jens

    2015-09-07

    Knowledge of what dose-volume histograms can be expected for a previously unseen patient could increase consistency and quality in radiotherapy treatment planning. We propose a machine learning method that uses previous treatment plans to predict such dose-volume histograms. The key to the approach is the framing of dose-volume histograms in a probabilistic setting.The training consists of estimating, from the patients in the training set, the joint probability distribution of some predictive features and the dose. The joint distribution immediately provides an estimate of the conditional probability of the dose given the values of the predictive features. The prediction consists of estimating, from the new patient, the distribution of the predictive features and marginalizing the conditional probability from the training over this. Integrating the resulting probability distribution for the dose yields an estimate of the dose-volume histogram.To illustrate how the proposed method relates to previously proposed methods, we use the signed distance to the target boundary as a single predictive feature. As a proof-of-concept, we predicted dose-volume histograms for the brainstems of 22 acoustic schwannoma patients treated with stereotactic radiosurgery, and for the lungs of 9 lung cancer patients treated with stereotactic body radiation therapy. Comparing with two previous attempts at dose-volume histogram prediction we find that, given the same input data, the predictions are similar.In summary, we propose a method for dose-volume histogram prediction that exploits the intrinsic probabilistic properties of dose-volume histograms. We argue that the proposed method makes up for some deficiencies in previously proposed methods, thereby potentially increasing ease of use, flexibility and ability to perform well with small amounts of training data.

  5. Radiation Dose Optimization For Critical Organs

    NASA Astrophysics Data System (ADS)

    Khodadadegan, Yasaman

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

  6. Relevance of biotic pathways to the long-term regulation of nuclear waste disposal. Estimation of radiation dose to man resulting from biotic transport: the BIOPORT/MAXI1 software package. Volume 5

    SciTech Connect

    McKenzie, D.H.; Cadwell, L.L.; Gano, K.A.; Kennedy, W.E. Jr.; Napier, B.A.; Peloquin, R.A.; Prohammer, L.A.; Simmons, M.A.

    1985-10-01

    BIOPORT/MAXI1 is a collection of five computer codes designed to estimate the potential magnitude of the radiation dose to man resulting from biotic transport processes. Dose to man is calculated for ingestion of agricultural crops grown in contaminated soil, inhalation of resuspended radionuclides, and direct exposure to penetrating radiation resulting from the radionuclide concentrations established in the available soil surface by the biotic transport model. This document is designed as both an instructional and reference document for the BIOPORT/MAXI1 computer software package and has been written for two major audiences. The first audience includes persons concerned with the mathematical models of biological transport of commercial low-level radioactive wastes and the computer algorithms used to implement those models. The second audience includes persons concerned with exercising the computer program and exposure scenarios to obtain results for specific applications. The report contains sections describing the mathematical models, user operation of the computer programs, and program structure. Input and output for five sample problems are included. In addition, listings of the computer programs, data libraries, and dose conversion factors are provided in appendices.

  7. Radiation dose reduction in chest CT: a review.

    PubMed

    Kubo, Takeshi; Lin, Pei-Jan Paul; Stiller, Wolfram; Takahashi, Masaya; Kauczor, Hans-Ulrich; Ohno, Yoshiharu; Hatabu, Hiroto

    2008-02-01

    This article aims to summarize the available data on reducing radiation dose exposure in routine chest CT protocols. First, the general aspects of radiation dose in CT and radiation risk are discussed, followed by the effect of changing parameters on image quality. Finally, the results of previous radiation dose reduction studies are reviewed, and important information contributing to radiation dose reduction will be shared. A variety of methods and techniques for radiation dose reduction should be used to ensure that radiation exposure is kept as low as is reasonably achievable.

  8. Radiation dose study in nuclear medicine using GATE

    NASA Astrophysics Data System (ADS)

    Aguwa, Kasarachi

    Dose as a result of radiation exposure is the notion generally used to disclose the imparted energy in a volume of tissue to a potential biological effect. The basic unit defined by the international system of units (SI system) is the radiation absorbed dose, which is expressed as the mean imparted energy in a mass element of the tissue known as "gray" (Gy) or J/kg. The procedure for ascertaining the absorbed dose is complicated since it involves the radiation transport of numerous types of charged particles and coupled photon interactions. The most precise method is to perform a full 3D Monte Carlo simulation of the radiation transport. There are various Monte Carlo toolkits that have tool compartments for dose calculations and measurements. The dose studies in this thesis were performed using the GEANT4 Application for Emission Tomography (GATE) software (Jan et al., 2011) GATE simulation toolkit has been used extensively in the medical imaging community, due to the fact that it uses the full capabilities of GEANT4. It also utilizes an easy to-learn GATE macro language, which is more accessible than learning the GEANT4/C++ programming language. This work combines GATE with digital phantoms generated using the NCAT (NURBS-based cardiac-torso phantom) toolkit (Segars et al., 2004) to allow efficient and effective estimation of 3D radiation dose maps. The GATE simulation tool has developed into a beneficial tool for Monte Carlo simulations involving both radiotherapy and imaging experiments. This work will present an overview of absorbed dose of common radionuclides used in nuclear medicine and serve as a guide to a user who is setting up a GATE simulation for a PET and SPECT study.

  9. Radiation dose reduction in parasinus CT by spectral shaping.

    PubMed

    May, Matthias S; Brand, Michael; Lell, Michael M; Sedlmair, Martin; Allmendinger, Thomas; Uder, Michael; Wuest, Wolfgang

    2017-02-01

    Spectral shaping aims to narrow the X-ray spectrum of clinical CT. The aim of this study was to determine the image quality and the extent of radiation dose reduction that can be achieved by tin prefiltration for parasinus CT. All scans were performed with a third generation dual-source CT scanner. A study protocol was designed using 100 kV tube voltage with tin prefiltration (200 mAs) that provides image noise levels comparable to a low-dose reference protocol using 100 kV without spectral shaping (25 mAs). One hundred consecutive patients were prospectively enrolled and randomly assigned to the study or control group. All patients signed written informed consent. The study protocol was approved by the local Institutional Review Board and applies to the HIPAA. Subjective and objective image quality (attenuation values, image noise, and contrast-to-noise ratio (CNR)) were assessed. Radiation exposure was assessed as volumetric CT dose index, and effective dose was estimated. Mann-Whitney U test was performed for radiation exposure and for image noise comparison. All scans were of diagnostic image quality. Image noise in air, in the retrobulbar fat, and in the eye globe was comparable between both groups (all p > 0.05). CNReye globe/air did not differ significantly between both groups (p = 0.7). Radiation exposure (1.7 vs. 2.1 mGy, p < 0.01) and effective dose (0.055 vs. 0.066 mSv, p < 0.01) were significantly reduced in the study group. Radiation dose can be further reduced by 17% for low-dose parasinus CT by tin prefiltration maintaining diagnostic image quality.

  10. Strategies for reducing radiation dose in CT.

    PubMed

    McCollough, Cynthia H; Primak, Andrew N; Braun, Natalie; Kofler, James; Yu, Lifeng; Christner, Jodie

    2009-01-01

    In recent years, the media has focused on the potential danger of radiation exposure from CT, even though the potential benefit of a medically indicated CT far outweighs the potential risks. This attention has reminded the radiology community that doses must be as low as reasonably achievable (ALARA) while maintaining diagnostic image quality. To satisfy the ALARA principle, the dose reduction strategies described in this article must be well understood and properly used. The use of CT must also be justified for the specific diagnostic task.

  11. Optical fibres for high radiation dose environments

    NASA Astrophysics Data System (ADS)

    Henschel, H.; Kohn, O.; Schmidt, H. U.; Bawirzanski, E.; Landers, A.

    1994-06-01

    A variety of modern single mode (SM) and graded index (GI) fibres as well as a new pure silica multimode step index (MMSI) fibre with high OH content were irradiated at a Co-60 gamma ray source with a dose rate of approximately = 1.5Gy/s up to a total dose of 10(exp 6)Gy. The radiation-induced loss of all fibres was measured continuously during and after irradiation at discrete wavelengths (approximately = 850, approximately = 1070, approximately = 1300, approximately = 1550nm). With one SM fibre type also the 'breaking stress' before and after irradiation was determined. Radiation-induced losses of approximately less than 5dB/50m (at approximately = 1300nm) were found with some of the SM fibres, whereas the MMSI fibre showed a final induced loss of only 0.5dB/50m at 1070nm wavelength. The breaking stress of the SM fibre increased by about 10%.

  12. Location Modification Factors for Potential Dose Estimation

    SciTech Connect

    Snyder, Sandra F.; Barnett, J. Matthew

    2017-01-01

    A Department of Energy facility must comply with the National Emission Standard for Hazardous Air Pollutants for radioactive air emissions. The standard is an effective dose of less than 0.1 mSv yr-1 to the maximum public receptor. Additionally, a lower dose level may be assigned to a specific emission point in a State issued permit. A method to efficiently estimate the expected dose for future emissions is described. This method is most appropriately applied to a research facility with several emission points with generally low emission levels of numerous isotopes.

  13. Radiation dose optimization in the decommissioning plan for Loviisa NPP

    SciTech Connect

    Holmberg, R.; Eurajoki, T.

    1995-03-01

    Finnish rules for nuclear power require a detailed decommissioning plan to be made and kept up to date already during plant operation. The main reasons for this {open_quotes}premature{close_quotes} plan, is, firstly, the need to demonstrate the feasibility of decommissioning, and, secondly, to make realistic cost estimates in order to fund money for this future operation. The decomissioning for Lovissa Nuclear Power Plant (NPP) (2{times}445 MW, PWR) was issued in 1987. It must be updated about every five years. One important aspect of the plant is an estimate of radiation doses to the decomissioning workers. The doses were recently re-estimated because of a need to decrease the total collective dose estimate in the original plan, 23 manSv. In the update, the dose was reduced by one-third. Part of the reduction was due to changes in the protection and procedures, in which ALARA considerations were taken into account, and partly because of re-estimation of the doses.

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

    SciTech Connect

    Bartine, D.E.; Cacuci, D.G.

    1983-09-13

    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. (ACR)

  15. Extended range radiation dose-rate monitor

    DOEpatents

    Valentine, Kenneth H.

    1988-01-01

    An extended range dose-rate monitor is provided which utilizes the pulse pileup phenomenon that occurs in conventional counting systems to alter the dynamic response of the system to extend the dose-rate counting range. The current pulses from a solid-state detector generated by radiation events are amplified and shaped prior to applying the pulses to the input of a comparator. The comparator generates one logic pulse for each input pulse which exceeds the comparator reference threshold. These pulses are integrated and applied to a meter calibrated to indicate the measured dose-rate in response to the integrator output. A portion of the output signal from the integrator is fed back to vary the comparator reference threshold in proportion to the output count rate to extend the sensitive dynamic detection range by delaying the asymptotic approach of the integrator output toward full scale as measured by the meter.

  16. Dose Estimation from Daily and Weekly Dosimetry Data

    SciTech Connect

    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 amount of bias also varies

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

    SciTech Connect

    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.

  18. Background radiation dose of dumpsites in Ota and Environs

    NASA Astrophysics Data System (ADS)

    Usikalu, M. R.; Ola, O. O.; Achuka, J. A.; Babarimisa, I. O.; Ayara, W. A.

    2017-05-01

    In-situ measurement of background radiation dose from selected dumpsites in Ota and its environs was done using Radialert Nuclear Radiation Monitor (Digilert 200). Ten measurements were taken from each dumpsite. The measured background radiation range between 0.015 mRhr-1 for AOD and 0.028 mRhr-1 for SUS dumpsites. The calculated annual equivalent doses vary between 1.31 mSvyr-1 for AOD and 2.28 mSv/yr for SUS dumpsites. The air absorbed dose calculated ranged from 150 nGyhr-1 to 280 nGy/hr for AOD and SUS dumpsites respectively with an average value of 217 nGyhr-1 for all the locations. All the estimated parameters were higher than permissible limit set for background radiation for the general public. Conclusively, the associated challenge and radiation burden posed by the wastes on the studied locations and scavengers is high. Therefore, there is need by the regulatory authorities to look into the way and how waste can be properly managed so as to alleviate the effects on the populace leaving and working in the dumpsites vicinity.

  19. EXPOSURE RELATED DOSE ESTIMATING MODEL (ERDEM)

    EPA Science Inventory

    ERDEM is a physiologically-based pharmacokinetic (PBPK) model with a graphical user interface (GUI) front end. Such a mathematical model was needed to make reliable estimates of the chemical dose to organs of animals or humans because of uncertainties of making route-to route, lo...

  20. EXPOSURE RELATED DOSE ESTIMATING MODEL (ERDEM)

    EPA Science Inventory

    ERDEM is a physiologically-based pharmacokinetic (PBPK) model with a graphical user interface (GUI) front end. Such a mathematical model was needed to make reliable estimates of the chemical dose to organs of animals or humans because of uncertainties of making route-to route, lo...

  1. 42 CFR 81.6 - Use of radiation dose information.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Use of radiation dose information. 81.6 Section 81... Probability of Causation § 81.6 Use of radiation dose information. Determining probability of causation will require the use of radiation dose information provided to DOL by the National Institute for...

  2. 42 CFR 81.6 - Use of radiation dose information.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Use of radiation dose information. 81.6 Section 81... Probability of Causation § 81.6 Use of radiation dose information. Determining probability of causation will require the use of radiation dose information provided to DOL by the National Institute for Occupational...

  3. 42 CFR 81.6 - Use of radiation dose information.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Use of radiation dose information. 81.6 Section 81... Probability of Causation § 81.6 Use of radiation dose information. Determining probability of causation will require the use of radiation dose information provided to DOL by the National Institute for Occupational...

  4. 42 CFR 81.6 - Use of radiation dose information.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Use of radiation dose information. 81.6 Section 81... Probability of Causation § 81.6 Use of radiation dose information. Determining probability of causation will require the use of radiation dose information provided to DOL by the National Institute for Occupational...

  5. 42 CFR 81.6 - Use of radiation dose information.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Use of radiation dose information. 81.6 Section 81... Probability of Causation § 81.6 Use of radiation dose information. Determining probability of causation will require the use of radiation dose information provided to DOL by the National Institute for Occupational...

  6. Trans-Atlantic Comparison of CT Radiation Doses in the Era of Radiation Dose-Tracking Software.

    PubMed

    Parakh, Anushri; Euler, Andre; Szucs-Farkas, Zsolt; Schindera, Sebastian T

    2017-09-12

    The purpose of this study is to compare diagnostic reference levels from a local European CT dose registry, using radiation-tracking software from a large patient sample, with preexisting European and North American diagnostic reference levels. Data (n = 43,761 CT scans obtained over the course of 2 years) for the European local CT dose registry were obtained from eight CT scanners at six institutions. Means, medians, and interquartile ranges of volumetric CT dose index (CTDIvol), dose-length product (DLP), size-specific dose estimate, and effective dose values for CT examinations of the head, paranasal sinuses, thorax, pulmonary angiogram, abdomen-pelvis, renal-colic, thorax-abdomen-pelvis, and thoracoabdominal angiogram were obtained using radiation-tracking software. Metrics from this registry were compared with diagnostic reference levels from Canada and California (published in 2015), the American College of Radiology (ACR) dose index registry (2015), and national diagnostic reference levels from local CT dose registries in Switzerland (2010), the United Kingdom (2011), and Portugal (2015). Our local registry had a lower 75th percentile CTDIvol for all protocols than did the individual internationally sourced data. Compared with our study, the ACR dose index registry had higher 75th percentile CTDIvol values by 55% for head, 240% for thorax, 28% for abdomen-pelvis, 42% for thorax-abdomen-pelvis, 128% for pulmonary angiogram, 138% for renal-colic, and 58% for paranasal sinus studies. Our local registry had lower diagnostic reference level values than did existing European and North American diagnostic reference levels. Automated radiation-tracking software could be used to establish and update existing diagnostic reference levels because they are capable of analyzing large datasets meaningfully.

  7. Low Dose Ionizing Radiation Modulates Immune Function

    SciTech Connect

    Nelson, Gregory A.

    2016-01-12

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

  8. Fetal radiation dose in computed tomography.

    PubMed

    Kelaranta, Anna; Kaasalainen, Touko; Seuri, Raija; Toroi, Paula; Kortesniemi, Mika

    2015-07-01

    The connection between recorded volumetric CT dose index (CTDI vol) and determined mean fetal dose (Df) was examined from metal-oxide-semiconductor field-effect transistor dose measurements on an anthropomorphic female phantom in four stages of pregnancy in a 64-slice CT scanner. Automated tube current modulation kept the mean Df fairly constant through all pregnancy stages in trauma (4.4-4.9 mGy) and abdomino-pelvic (2.1-2.4 mGy) protocols. In pulmonary angiography protocol, the mean Df increased exponentially as the distance from the end of the scan range decreased (0.01-0.09 mGy). For trauma protocol, the relative mean Df as a function of gestational age were in the range 0.80-0.97 compared with the mean CTDI vol. For abdomino-pelvic protocol, the relative mean Df was 0.57-0.79 and for pulmonary angiography protocol, 0.01-0.05 compared with the mean CTDI vol, respectively. In conclusion, if the fetus is in the primary beam, the CTDI vol can be used as an upper estimate of the fetal dose. If the fetus is not in the primary beam, the fetal dose can be estimated by considering also the distance of the fetus from the scan range.

  9. Estimating potential evapotranspiration with improved radiation estimation

    USDA-ARS?s Scientific Manuscript database

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

  10. Analytic estimates of secondary neutron dose in proton therapy.

    PubMed

    Anferov, V

    2010-12-21

    Proton beam losses in various components of a treatment nozzle generate secondary neutrons, which bring unwanted out of field dose during treatments. The purpose of this study was to develop an analytic method for estimating neutron dose to a distant organ at risk during proton therapy. Based on radiation shielding calculation methods proposed by Sullivan, we developed an analytical model for converting the proton beam losses in the nozzle components and in the treatment volume into the secondary neutron dose at a point of interest. Using the MCNPx Monte Carlo code, we benchmarked the neutron dose rates generated by the proton beam stopped at various media. The Monte Carlo calculations confirmed the validity of the analytical model for simple beam stop geometry. The analytical model was then applied to neutron dose equivalent measurements performed on double scattering and uniform scanning nozzles at the Midwest Proton Radiotherapy Institute (MPRI). Good agreement was obtained between the model predictions and the data measured at MPRI. This work provides a method for estimating analytically the neutron dose equivalent to a distant organ at risk. This method can be used as a tool for optimizing dose delivery techniques in proton therapy.

  11. Developing milk industry estimates for dose reconstruction projects

    SciTech Connect

    Beck, D.M.; Darwin, R.F. )

    1991-01-01

    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.

  12. The Radiation Dose-Response of the Human Spinal Cord

    SciTech Connect

    Schultheiss, Timothy E.

    2008-08-01

    Purpose: To characterize the radiation dose-response of the human spinal cord. Methods and Materials: Because no single institution has sufficient data to establish a dose-response function for the human spinal cord, published reports were combined. Requisite data were dose and fractionation, number of patients at risk, number of myelopathy cases, and survival experience of the population. Eight data points for cervical myelopathy were obtained from five reports. Using maximum likelihood estimation correcting for the survival experience of the population, estimates were obtained for the median tolerance dose, slope parameter, and {alpha}/{beta} ratio in a logistic dose-response function. An adequate fit to thoracic data was not possible. Hyperbaric oxygen treatments involving the cervical cord were also analyzed. Results: The estimate of the median tolerance dose (cervical cord) was 69.4 Gy (95% confidence interval, 66.4-72.6). The {alpha}/{beta} = 0.87 Gy. At 45 Gy, the (extrapolated) probability of myelopathy is 0.03%; and at 50 Gy, 0.2%. The dose for a 5% myelopathy rate is 59.3 Gy. Graphical analysis indicates that the sensitivity of the thoracic cord is less than that of the cervical cord. There appears to be a sensitizing effect from hyperbaric oxygen treatment. Conclusions: The estimate of {alpha}/{beta} is smaller than usually quoted, but values this small were found in some studies. Using {alpha}/{beta} = 0.87 Gy, one would expect a considerable advantage by decreasing the dose/fraction to less than 2 Gy. These results were obtained from only single fractions/day and should not be applied uncritically to hyperfractionation.

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

    NASA Astrophysics Data System (ADS)

    Mitrikas, Victor; Aleksandr, Shafirkin; Shurshakov, Vyacheslav

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

  14. Radiation doses in paediatric interventional cardiology procedures.

    PubMed

    Tsapaki, Virginia; Kottou, Sofia; Korniotis, Sarantis; Nikolaki, Niki; Rammos, Spyridon; Apostolopoulou, Sotiria C

    2008-01-01

    The objective was to investigate paediatric doses in coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA) in the largest cardiac hospital in Greece. Forty procedures were carried out by two board-certified senior interventional cardiologists. Data collected were: patient weight, height, age, fluoroscopy time (FT), total number of images (N) and kerma-area product (KAP). Median (range) age was 7.5 y (17 d to 17 y). Median FT, N and KAP were 4 min, 655, 2.1 Gy cm2 for CA and 12.1 min, 1296, 14.7 Gy cm2 for PTCA (corresponding adult diagnostic reference levels (DRLs) are: 6.5 min, 700, 45 Gy cm2 for CA and 15.5 min, 1000 and 85 Gy cm2 for PTCA). The highest percentage of cine dose was in newborns (0-1 y) (CA: 92% and PTCA: 100%). As age increased, cine dose percentage decreased, whereas total radiation dose increased. Median paediatric FT and N recorded reached or even exceeded adult DRL and should be optimised. Paediatric DRL should be set.

  15. Contribution of maternal radionuclide burdens to prenatal radiation doses

    SciTech Connect

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

    1996-05-01

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

  16. 78 FR 14303 - Subcommittee for Dose Reconstruction Reviews (SDRR), Advisory Board on Radiation and Worker...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-05

    ... (SDRR), Advisory Board on Radiation and Worker Health (ABRWH or the Advisory Board), National Institute... employees at any Department of Energy facility who were exposed to radiation but for whom it is not feasible to estimate their radiation dose, and on whether there is reasonable likelihood that such...

  17. 78 FR 78964 - Subcommittee for Dose Reconstruction Reviews (SDRR), Advisory Board on Radiation and Worker...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-27

    ... (SDRR), Advisory Board on Radiation and Worker Health (ABRWH or the Advisory Board), National Institute... employees at any Department of Energy (DOE) facility who were exposed to radiation but for whom it is not feasible to estimate their radiation dose, and on whether there is reasonable likelihood that such...

  18. Quantification of contralateral breast dose and risk estimate of radiation-induced contralateral breast cancer among young women using tangential fields and different modes of breathing.

    PubMed

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

    2013-02-01

    Whole breast irradiation with deep-inspiration breath-hold (DIBH) technique among left-sided breast cancer patients significantly reduces cardiac irradiation; however, a potential disadvantage is increased incidental irradiation of the contralateral breast. Contralateral breast dose (CBD) was calculated by comparing 400 treatment plans of 200 left-sided breast cancer patients whose tangential fields had been planned on gated and nongated CT data sets. Various anatomic and field parameters were analyzed for their impact on CBD. For a subgroup of patients (aged ≤45 years) second cancer risk in the contralateral breast (CB) was modeled by applying the linear quadratic model, compound models, and compound models considering dose-volume information (DVH). The mean CBD was significantly higher in DIBH with 0.69 Gy compared with 0.65 Gy in normal breathing (P=.01). The greatest impact on CBD was due to a shift of the inner field margin toward the CB in DIBH (mean 0.4 cm; range, 0-2), followed by field size in magnitude. Calculation with different risk models for CBC revealed values of excess relative risk/Gy ranging from 0.48-0.65 vs 0.46-0.61 for DIBH vs normal breathing, respectively. Contralateral breast dose, although within a low dose range, was mildly but significantly increased in 200 treatment plans generated under gated conditions, predominately due to a shift in the medial field margin. Risk modeling for CBC among women aged ≤45 years also pointed to a higher risk when comparing DIBH with normal breathing. This risk, however, was substantially lower in the model considering DVH information. We think that clinical decisions should not be affected by this small increase in CBD with DIBH because DIBH is effective in reducing the dose to the heart in all patients. Copyright © 2013 Elsevier Inc. All rights reserved.

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

    SciTech Connect

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

    2013-02-01

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

  20. 76 FR 72416 - Subcommittee for Dose Reconstruction Reviews (SDRR), Advisory Board on Radiation and Worker...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-23

    ... Prevention Subcommittee for Dose Reconstruction Reviews (SDRR), Advisory Board on Radiation and Worker Health... promulgated by the Department of Health and Human Services (HHS) as a final rule; advice on methods of dose... quality of dose estimation and reconstruction efforts being performed for purposes of the...

  1. Non-uniform dose distributions in cranial radiation therapy

    NASA Astrophysics Data System (ADS)

    Bender, Edward T.

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

  2. Estimation Of Organ Doses From Solar Particle Events For Future Space Exploration Missions

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee; Cucinotta, Francis A.

    2006-01-01

    Radiation protection practices define the effective dose as a weighted sum of equivalent dose over major organ sites for radiation cancer risks. Since a crew personnel dosimeter does not make direct measurement of the effective dose, it has been estimated with skin-dose measurements and radiation transport codes for ISS and STS missions. If sufficient protection is not provided near solar maximum, the radiation risk can be significant due to exposure to sporadic solar particle events (SPEs) as well as to the continuous galactic cosmic radiation (GCR) on future exploratory-class and long-duration missions. For accurate estimates of overall fatal cancer risks from SPEs, the specific doses at various blood forming organs (BFOs) were considered, because proton fluences and doses vary considerably across marrow regions. Previous estimates of BFO doses from SPEs have used an average body-shielding distribution for the bone marrow based on the computerized anatomical man model (CAM). With the development of an 82-point body-shielding distribution at BFOs, the mean and variance of SPE doses in the major active marrow regions (head and neck, chest, abdomen, pelvis and thighs) will be presented. Consideration of the detailed distribution of bone marrow sites is one of many requirements to improve the estimation of effective doses for radiation cancer risks.

  3. Estimation Of Organ Doses From Solar Particle Events For Future Space Exploration Missions

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee; Cucinotta, Francis A.

    2006-01-01

    Radiation protection practices define the effective dose as a weighted sum of equivalent dose over major organ sites for radiation cancer risks. Since a crew personnel dosimeter does not make direct measurement of the effective dose, it has been estimated with skin-dose measurements and radiation transport codes for ISS and STS missions. If sufficient protection is not provided near solar maximum, the radiation risk can be significant due to exposure to sporadic solar particle events (SPEs) as well as to the continuous galactic cosmic radiation (GCR) on future exploratory-class and long-duration missions. For accurate estimates of overall fatal cancer risks from SPEs, the specific doses at various blood forming organs (BFOs) were considered, because proton fluences and doses vary considerably across marrow regions. Previous estimates of BFO doses from SPEs have used an average body-shielding distribution for the bone marrow based on the computerized anatomical man model (CAM). With the development of an 82-point body-shielding distribution at BFOs, the mean and variance of SPE doses in the major active marrow regions (head and neck, chest, abdomen, pelvis and thighs) will be presented. Consideration of the detailed distribution of bone marrow sites is one of many requirements to improve the estimation of effective doses for radiation cancer risks.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

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

    USDA-ARS?s Scientific Manuscript database

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

  6. Patient-specific dose estimation for pediatric chest CT

    SciTech Connect

    Li Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Frush, Donald P.

    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 dose for

  7. Multiple Testing, Cumulative Radiation Dose, and Clinical Indications in Patients Undergoing Myocardial Perfusion Imaging

    PubMed Central

    Einstein, Andrew J.; Weiner, Shepard D.; Bernheim, Adam; Kulon, Michal; Bokhari, Sabahat; Johnson, Lynne L.; Moses, Jeffrey W.; Balter, Stephen

    2013-01-01

    Context Myocardial perfusion imaging (MPI) is the single medical test with the highest radiation burden to the US population. While many patients undergoing MPI receive repeat MPI testing, or additional procedures involving ionizing radiation, no data are available characterizing their total longitudinal radiation burden and relating radiation burden with reasons for testing. Objective To characterize procedure counts, cumulative estimated effective doses of radiation, and clinical indications, for patients undergoing MPI. Design, Setting, Patients Retrospective cohort study evaluating, for 1097 consecutive patients undergoing index MPI during the first 100 days of 2006 at Columbia University Medical Center, all preceding medical imaging procedures involving ionizing radiation undergone beginning October 1988, and all subsequent procedures through June 2008, at that center. Main Outcome Measures Cumulative estimated effective dose of radiation, number of procedures involving radiation, and indications for testing. Results Patients underwent a median (interquartile range, mean) of 15 (6–32, 23.9) procedures involving radiation exposure; 4 (2–8, 6.5) were high-dose (≥3 mSv, i.e. one year's background radiation), including 1 (1–2, 1.8) MPI studies per patient. 31% of patients received cumulative estimated effective dose from all medical sources >100mSv. Multiple MPIs were performed in 39% of patients, for whom cumulative estimated effective dose was 121 (81–189, 149) mSv. Men and whites had higher cumulative estimated effective doses, and there was a trend towards men being more likely to undergo multiple MPIs than women (40.8% vs. 36.6%, Odds ratio 1.29, 95% confidence interval 0.98–1.69). Over 80% of initial and 90% of repeat MPI exams were performed in patients with known cardiac disease or symptoms consistent with it. Conclusion In this institution, multiple testing with MPI was very common, and in many patients associated with very high cumulative

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

    NASA Astrophysics Data System (ADS)

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

    2011-08-01

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

  9. Estimating solar radiation for plant simulation models

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  10. Radiation dose-reduction strategies in thoracic CT.

    PubMed

    Moser, J B; Sheard, S L; Edyvean, S; Vlahos, I

    2017-05-01

    Modern computed tomography (CT) machines have the capability to perform thoracic CT for a range of clinical indications at increasingly low radiation doses. This article reviews several factors, both technical and patient-related, that can affect radiation dose and discusses current dose-reduction methods relevant to thoracic imaging through a review of current techniques in CT acquisition and image reconstruction. The fine balance between low radiation dose and high image quality is considered throughout, with an emphasis on obtaining diagnostic quality imaging at the lowest achievable radiation dose. The risks of excessive radiation dose reduction are also considered. Inappropriately low dose may result in suboptimal or non-diagnostic imaging that may reduce diagnostic confidence, impair diagnosis, or result in repeat examinations incurring incremental ionising radiation exposure. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  11. Radiation Dose-Volume Effects of Optic Nerves and Chiasm

    SciTech Connect

    Mayo, Charles; Martel, Mary K.; Marks, Lawrence B.; Flickinger, John; Nam, Jiho; Kirkpatrick, John

    2010-03-01

    Publications relating radiation toxicity of the optic nerves and chiasm to quantitative dose and dose-volume measures were reviewed. Few studies have adequate data for dose-volume outcome modeling. The risk of toxicity increased markedly at doses >60 Gy at {approx}1.8 Gy/fraction and at >12 Gy for single-fraction radiosurgery. The evidence is strong that radiation tolerance is increased with a reduction in the dose per fraction. Models of threshold tolerance were examined.

  12. Practical strategies to reduce pediatric CT radiation dose.

    PubMed

    Nelson, Thomas R

    2014-03-01

    The objective of this article is to provide a brief review of CT scanning radiation sensitivity in children and explain CT scan parameters that affect radiation dose. We discuss key factors influencing radiation dose and study quality and how these factors can be used to optimize scan protocols with the goal of reducing pediatric CT radiation dose without compromising diagnostic quality. Finally, we provide some practical tips for reducing radiation doses to children. Copyright © 2014 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  13. Dose to medium versus dose to water as an estimator of dose to sensitive skeletal tissue

    NASA Astrophysics Data System (ADS)

    Walters, B. R. B.; Kramer, R.; Kawrakow, I.

    2010-08-01

    The purpose of this study is to determine whether dose to medium, Dm, or dose to water, Dw, provides a better estimate of the dose to the radiosensitive red bone marrow (RBM) and bone surface cells (BSC) in spongiosa, or cancellous bone. This is addressed in the larger context of the ongoing debate over whether Dm or Dw should be specified in Monte Carlo calculated radiotherapy treatment plans. The study uses voxelized, virtual human phantoms, FAX06/MAX06 (female/male), incorporated into an EGSnrc Monte Carlo code to perform Monte Carlo dose calculations during simulated irradiation by a 6 MV photon beam from an Elekta SL25 accelerator. Head and neck, chest and pelvis irradiations are studied. FAX06/MAX06 include precise modelling of spongiosa based on µCT images, allowing dose to RBM and BSC to be resolved from the dose to bone. Modifications to the FAX06/MAX06 user codes are required to score Dw and Dm in spongiosa. Dose uncertainties of ~1% (BSC, RBM) or ~0.5% (Dm, Dw) are obtained after up to 5 days of simulations on 88 CPUs. Clinically significant differences (>5%) between Dm and Dw are found only in cranial spongiosa, where the volume fraction of trabecular bone (TBVF) is high (55%). However, for spongiosa locations where there is any significant difference between Dm and Dw, comparisons of differential dose volume histograms (DVHs) and average doses show that Dw provides a better overall estimate of dose to RBM and BSC. For example, in cranial spongiosa the average Dm underestimates the average dose to sensitive tissue by at least 5%, while average Dw is within ~1% of the average dose to sensitive tissue. Thus, it is better to specify Dw than Dm in Monte Carlo treatment plans, since Dw provides a better estimate of dose to sensitive tissue in bone, the only location where the difference is likely to be clinically significant.

  14. Relationship between fluoroscopic time, dose-area product, body weight, and maximum radiation skin dose in cardiac interventional procedures.

    PubMed

    Chida, Koichi; Saito, Haruo; Otani, Hiroki; Kohzuki, Masahiro; Takahashi, Shoki; Yamada, Shogo; Shirato, Kunio; Zuguchi, Masayuki

    2006-03-01

    Real-time maximum dose monitoring of the skin is unavailable on many of the X-ray machines that are used for cardiac intervention procedures. Therefore, some reports have recommended that physicians record the fluoroscopic time for patients undergoing fluoroscopically guided intervention procedures. However, the relationship between the fluoroscopic time and the maximum radiation skin dose is not clear. This article describes the correlation between the maximum radiation skin dose and fluoroscopic time for patients undergoing cardiac intervention procedures. In addition, we examined whether the correlations between maximum radiation skin dose and body weight, fluoroscopic time, and dose-area product (DAP) were useful for estimating the maximum skin dose during cardiac intervention procedures. Two hundred consecutive cardiac intervention procedures were studied: 172 percutaneous coronary interventions and 28 cardiac radiofrequency catheter ablation (RFCA) procedures. The patient skin dose and DAP were measured using Caregraph with skin-dose-mapping software. For the RFCA procedures, we found a good correlation between the maximum radiation skin dose and fluoroscopic time (r = 0.801, p < 0.0001), whereas we found a poor correlation between the maximum radiation skin dose and fluoroscopic time for the percutaneous coronary intervention procedures (r = 0.628, p < 0.0001). There was a strong correlation between the maximum radiation skin dose and DAP in RFCA procedures (r = 0.942, p < 0.0001). There was also a significant correlation between the maximum radiation skin dose and DAP (r = 0.724, p < 0.0001) and weight-fluoroscopic time product (WFP) (r = 0.709, p < 0.0001) in percutaneous coronary intervention procedures. The correlation between the maximum radiation skin dose with DAP is more striking than that with fluoroscopic time in both RFCA and percutaneous coronary intervention procedures. We recommend that physicians record the DAP when it can be monitored and

  15. Effective Dose from Stray Radiation for a Patient Receiving Proton Therapy for Liver Cancer

    NASA Astrophysics Data System (ADS)

    Taddei, Phillip J.; Krishnan, Sunil; Mirkovic, Dragan; Yepes, Pablo; Newhauser, Wayne D.

    2009-03-01

    Because of its advantageous depth-dose relationship, proton radiotherapy is an emerging treatment modality for patients with liver cancer. Although the proton dose distribution conforms to the target, healthy tissues throughout the body receive low doses of stray radiation, particularly neutrons that originate in the treatment unit or in the patient. The aim of this study was to calculate the effective dose from stray radiation and estimate the corresponding risk of second cancer fatality for a patient receiving proton beam therapy for liver cancer. Effective dose from stray radiation was calculated using detailed Monte Carlo simulations of a double-scattering proton therapy treatment unit and a voxelized human phantom. The treatment plan and phantom were based on CT images of an actual adult patient diagnosed with primary hepatocellular carcinoma. For a prescribed dose of 60 Gy to the clinical target volume, the effective dose from stray radiation was 370 mSv; 61% of this dose was from neutrons originating outside of the patient while the remaining 39% was from neutrons originating within the patient. The excess lifetime risk of fatal second cancer corresponding to the total effective dose from stray radiation was 1.2%. The results of this study establish a baseline estimate of the stray radiation dose and corresponding risk for an adult patient undergoing proton radiotherapy for liver cancer and provide new evidence to corroborate the suitability of proton beam therapy for the treatment of liver tumors.

  16. Glandular dose in breast computed tomography with synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Mettivier, G.; Fedon, C.; Di Lillo, F.; Longo, R.; Sarno, A.; Tromba, G.; Russo, P.

    2016-01-01

    The purpose of this work is to provide an evaluation of the mean glandular dose (MGD) for breast computed tomography (CT) with synchrotron radiation in an axial scanning configuration with a partial or total organ volume irradiation, for the in vivo program of breast CT ongoing at the ELETTRA facility (Trieste, Italy). A Geant4 Monte Carlo code was implemented, simulating the photon irradiation from a synchrotron radiation source in the energetic range from 8 to 50 keV with 1 keV intervals, to evaluate the MGD. The code was validated with literature data, in terms of mammographic normalized glandular dose coefficients (DgN) and with ad hoc experimental data, in terms of computed tomography dose index (CTDI). Simulated cylindrical phantoms of different sizes (diameter at phantom base 8, 10, 12, 14 or 16 cm, axial length 1.5 times the radius) and glandular fraction by weight (0%, 14.3%, 25%, 50%, 75% and 100%) were implemented into the code. The validation of the code shows an excellent agreement both with previously published work and in terms of DgN and CDTI measurements. The implemented simulations show a dependence of the glandular dose estimate on the vertical dimension of the irradiated zone when a partial organ irradiation was implemented. Specific normalized coefficients for calculating the MGD to the whole breast or to the single irradiated slice were reported.

  17. Glandular dose in breast computed tomography with synchrotron radiation.

    PubMed

    Mettivier, G; Fedon, C; Di Lillo, F; Longo, R; Sarno, A; Tromba, G; Russo, P

    2016-01-21

    The purpose of this work is to provide an evaluation of the mean glandular dose (MGD) for breast computed tomography (CT) with synchrotron radiation in an axial scanning configuration with a partial or total organ volume irradiation, for the in vivo program of breast CT ongoing at the ELETTRA facility (Trieste, Italy). A Geant4 Monte Carlo code was implemented, simulating the photon irradiation from a synchrotron radiation source in the energetic range from 8 to 50 keV with 1 keV intervals, to evaluate the MGD. The code was validated with literature data, in terms of mammographic normalized glandular dose coefficients (DgN) and with ad hoc experimental data, in terms of computed tomography dose index (CTDI). Simulated cylindrical phantoms of different sizes (diameter at phantom base 8, 10, 12, 14 or 16 cm, axial length 1.5 times the radius) and glandular fraction by weight (0%, 14.3%, 25%, 50%, 75% and 100%) were implemented into the code. The validation of the code shows an excellent agreement both with previously published work and in terms of DgN and CDTI measurements. The implemented simulations show a dependence of the glandular dose estimate on the vertical dimension of the irradiated zone when a partial organ irradiation was implemented. Specific normalized coefficients for calculating the MGD to the whole breast or to the single irradiated slice were reported.

  18. Asian consortium on radiation dose of pediatric cardiac CT (ASCI-REDCARD).

    PubMed

    Hui, Peter K T; Goo, Hyun Woo; Du, Jing; Ip, Janice J K; Kanzaki, Suzu; Kim, Young Jin; Kritsaneepaiboon, Supika; Lilyasari, Oktavia; Siripornpitak, Suvipaporn

    2017-07-01

    With incremental utilization of pediatric cardiac CT in congenital heart disease, it is imperative to define its current radiation dose levels in clinical practice in order to help imagers optimize CT protocols, particularly in Asia and other developing countries where CT physicists are not readily available. To evaluate current radiation dose levels and influencing factors in cardiac CT in children with congenital heart disease in Asia by conducting a retrospective multi-center, multi-vendor study. We included 1,043 pediatric cardiac CT examinations performed in 8 centers between January 2014 and December 2014 to evaluate congenital heart disease. In five weight groups, we calculated radiation dose metrics including volume CT dose index, size-specific dose estimate, dose-length product and effective dose. Age at CT exam, gender, tube voltage, scan mode, CT indication and image reconstruction algorithm were analyzed to learn whether they influenced CT radiation dose. Volume CT dose index, size-specific dose estimate, dose-length product and effective dose of pediatric cardiac CT showed variations in the range of 4.3-23.8 mGy, 4.9-17.6 mGy, 55.8-501.3 mGy∙cm and 1.5-3.2 mSv, respectively, within five weight groups. Gender, tube voltage, scan mode and cardiac function assessment significantly influenced CT radiation dose. This multi-center, multi-vendor study demonstrated variations in radiation dose metrics of pediatric cardiac CT reflecting current practice in Asia. Gender, tube voltage, scan mode and cardiac function assessment should be considered as essential radiation dose-influencing factors in developing optimal pediatric cardiac CT protocols.

  19. Estimation of Secondary Neutron Dose during Proton Therapy

    NASA Astrophysics Data System (ADS)

    Urban, Tomas; Klusoň, Jaroslav

    2014-06-01

    During proton radiotherapy, secondary neutrons are produced by nuclear interactions in the material along the beam path, in the treatment nozzle (including the fixed scatterer, range modulator, etc.) and, of course, after entering the patient. The dose equivalent deposited by these neutrons is usually not considered in routine treatment planning. In this study, there has been estimated the neutron dose in patient (in as well as around the target volume) during proton radiotherapy using scattering and scanning techniques. The proton induced neutrons (and photons) have been simulated in the simple geometry of the single scattering and the pencil beam scanning universal nozzles and in geometry of the plastic phantom (made of tissue equivalent material - RW3 - imitate the patient). In simulations of the scattering nozzle, different types of brass collimators have been used as well. Calculated data have been used as an approximation of the radiation field in and around the chosen/potential target volume in the patient (plastic phantom). For the dose equivalent evaluation, fluence-to-dose conversion factors from ICRP report have been employed. The results of calculated dose from neutrons in various distances from the spot for different treatment technique and for different energies of incident protons have been compared and evaluated in the context of the dose deposited in the target volume. This work was supported by RVO: 68407700 and Grant Agency of the CTU in Prague, grant No. SGS12/200/OHK4/3T/14.

  20. Analysis of radiation doses from operation of postulated commercial spent fuel transportation systems: Main report

    SciTech Connect

    Schneider, K.J.; Hostick, C.J.; Ross, W.A.; Peterson, R.W.; Smith, R.I.; Stiles, D.L.; Daling, P.M.; Weakley, S.A.; Grinde, R.B.; Young, J.R.

    1987-11-01

    This report contains a system study of estimated radiation doses to the public and workers resulting from the transport of spent fuel from commercial nuclear power reactors to a geologic repository. The report contains a detailed breakdown of activities and a description of time/distance/dose-rate estimates for each activity within the system. Collective doses are estimated for each of the major activities at the reactor site, in transit, and at the repository receiving facility. Annual individual doses to the maximally exposed individuals or groups of individuals are also estimated. A total of 17 alternatives and subalternatives to the postulated reference transportation system are identified, conceptualized, and their dose-reduction potentials and costs estimated. Resulting ratios of ..delta..cost/..delta..collective system dose for each alternative relative to the postulated reference transportation system are given. Most of the alternatives evaluated are estimated to provide both cost and dose reductions. Major reductions in transportation system dose and cost are estimated to result from using higher-capacity rail and truck casks, and particularly when replacing legalweight truck casks with ''advanced design'' overweight truck casks. The greatest annual dose reduction to the highest exposed individual workers (i.e., at the repository) is estimated to be achieved by using remote handling equipment for the cask handling operations at the repository. Additional shielding is also effective in reducing doses to both radiation workers at the reactor and repository and to transport workers. 69 refs., 36 figs., 156 tabs.

  1. Variations of the radiation dose onboard Mir station.

    PubMed

    Panasyuk, M I; Teltsov, M V; Shumshurov, V I; Tsetlin, V V

    1998-01-01

    Dose variations, associated with the 11-year solar activity cycle, seasonal variations of particle fluxes in the Earth's radiation belts at the station orbit, and solar proton events are studied, using prolonged measurements of radiation doses inside orbital station Mir. Daily averages of radiation doses during the declining phase of the 22nd solar cycle and during transition to the 23rd solar activity cycle reached very large values for astronauts and significantly exceed the values calculated according to existing models.

  2. Measurement and assessment of radiation dose of astronauts in space

    NASA Astrophysics Data System (ADS)

    Zhang, Binquan; Sun, Yue-qiang; Yang, Chuibai; Zhang, Shenyi; Liang, Jinbao

    Astronauts in flight are exposed by the space radiation, which is mainly composed of proton, electron, heavy ion, and neutron. To assess the radiation risk, measurement and assessment of radiation dose of astronauts is indispensable. Especially, measurement for heavy ion radiation is most important as it contributes the major dose. Until now, most of the measurements and assessments of radiation dose of astronauts are based on the LET (Linear Energy Transfer) spectrum of space radiation. However, according to the ICRP Publication 123, energy and charge number of heavy ions should be measured in order to assess space radiation exposure to astronauts. In addition, from the publication, quality factors for each organs or tissues of astronauts are different and they should be calculated or measured independently. Here, a method to measure the energy and charge number of heavy ion and a voxel phantom based on the anatomy of Chinese adult male are presented for radiation dose assessment of astronauts.

  3. The median lethal dose and its estimation.

    PubMed

    Finney, D J

    1985-02-01

    An important paper by Zbinden and Fluri-Roversi (1981) has shown the many weaknesses in any policy or regulatory system that regards an estimated LD50 in an animal species as an adequate guide to toxicity in man. The present paper draws attention to some statistical aspects of LD50 estimation that are too often neglected or misunderstood when this quantity is wanted. It is solely concerned with practice when a LD50 must be estimated, and deliberately does not approach the broader issues of whether the LD50 should be estimated. A first need is clear distinction between the true but unknown form of dependence of mortality on dose and the estimate of it (or of a particular property such as the LD50) that is obtainable from an experiment. Some assumptions are necessary before any estimation is possible. The graphical and semi-graphical methods that once were popular because of their simplicity and speed are today only reasonable as a last resort, when data are wholly inadequate and all that can be found is a very rough preliminary indication. Many "simple" arithmetical methods have been shown to be inherently bad, in that equally simple alternatives are usually more precise and less subject to bias. The Spearman-Kärber method remains as a useful possibility, demanding little knowledge of the form of the response curves but often needing other unverifiable assumptions. For most purposes, maximum likelihood estimation of a parametric formulation of the response curve is the best choice, not only because of theoretical merits but also because it can now be performed on a microcomputer in a very few seconds.

  4. Thyroid neoplasia following low-dose radiation in childhood

    SciTech Connect

    Ron, E.; Modan, B.; Preston, D.; Alfandary, E.; Stovall, M.; Boice, J.D. Jr. )

    1989-12-01

    The thyroid gland is highly sensitive to the carcinogenic effects of ionizing radiation. Previously, we reported a significant increase of thyroid cancer and adenomas among 10,834 persons in Israel who received radiotherapy to the scalp for ringworm. These findings have now been extended with further follow-up and revised dosimetry. Overall, 98 thyroid tumors were identified among the exposed and 57 among 10,834 nonexposed matched population and 5392 sibling comparison subjects. An estimated thyroid dose of 9 cGy was linked to a fourfold (95% Cl = 2.3-7.9) increase of malignant tumors and a twofold (95% Cl = 1.3-3.0) increase of benign tumors. The dose-response relationship was consistent with linearity. Age was an important modifier of risk with those exposed under 5 years being significantly more prone to develop thyroid tumors than older children. The pattern of radiation risk over time could be described on the basis of a constant multiplication of the background rate, and an absolute risk model was not compatible with the observed data. Overall, the excess relative risk per cGy for thyroid cancer development after childhood exposure is estimated as 0.3, and the absolute excess risk as 13 per 10(6) PY-cGy. For benign tumors the estimated excess relative risk was 0.1 per cGy and the absolute risk was 15 per 10(6) PY-cGy.

  5. Estimating γ-rays dose using computer

    NASA Astrophysics Data System (ADS)

    Al-Rawi, Anis M.; Muslih, Raad M.; Al-Harithy, Rafila S.

    When gum arabic is exposed to γ-rays, a change in its reflection and absorption ability for the different wave lengths is obtained. This change is used for estimating the absorbed γ-rays directly. In the present work we are not concerned with the type of components that are chemically formed as emphasis will only be put on the physical changes. The physical state is taken as a potential chemical change since a molecular damage is accumulated as a result of the dose absorbed. The fortran IV data General (Nova 3) designed for estimating colour measurements was connected to a spectrophotometer that enables measuring the changes in both absorbing and reflecting or even diffusing of light through irradiated materials.

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

    PubMed

    Lofthag-Hansen, Sara

    2010-01-01

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

  7. Risk of cancer subsequent to low-dose radiation

    SciTech Connect

    Warren, S.

    1980-01-01

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

  8. [Multislice CT in a diagnostic imaging department: radiation doses delivered in 1 year.].

    PubMed

    Salmerón, Isabel; Calzado, Alfonso; Ruiz-López, Laura; Alonso, Verónica; Cordeiro, César; Fraile, Eduardo

    2009-01-01

    To determine the usage of CT in our diagnostic imaging department and the dose of radiation CT delivered to patients. We carried out two studies, a retrospective study on the administrative data from one year and a prospective study over one month, to determine the amount of activity of the two multislice CT scanners in our department. We recorded the total number of examinations, the different types of examination performed, and the age distributions of the patients examined. We used these data and the results of dosimetric measurements to estimate the typical radiation dose for each type of examination, its contribution to the collective radiation dose, and the total collective radiation dose from CT examinations at our hospital. The retrospective study found that 15038 examinations were performed in 12678 patients in one year. The most common CT examinations were cranial (38.2%), abdomen-pelvis (17.5%), chest-abdomen (11.7%), chest (9.3%), and lumbar-sacral spine (6.8%). Some protocols used doses of radiation that were higher than those recommended by European experts. The total collective dose of radiation delivered to patients at our hospital by CT was estimated at 70 person.Sv. Abdomen-pelvis examinations contributed 31% of the total dose. This study has provided detailed knowledge about the use of CT in our diagnostic imaging department, about the dose of radiation delivered, and about possibilities for improving the use of our CT scanners.

  9. Influence of DTPA Treatment on Internal Dose Estimates.

    PubMed

    Davesne, Estelle; Blanchardon, Eric; Peleau, Bernadette; Correze, Philippe; Bohand, Sandra; Franck, Didier

    2016-06-01

    In case of internal contamination with plutonium materials, a treatment with diethylene triamine pentaacetic acid (DTPA) can be administered in order to reduce plutonium body burden and consequently avoid some radiation dose. DTPA intravenous injections or inhalation can start almost immediately after intake, in parallel with urinary and fecal bioassay sampling for dosimetric follow-up. However, urine and feces excretion will be significantly enhanced by the DTPA treatment. As internal dose is calculated from bioassay results, the DTPA effect on excretion has to be taken into account. A common method to correct bioassay data is to divide it by a factor representing the excretion enhancement under DTPA treatment by intravenous injection. Its value may be based on a nominal reference or observed after a break in the treatment. The aim of this study was to estimate the influence of this factor on internal dose by comparing the dose estimated using default or upper and lower values of the enhancement factor for 11 contamination cases. The observed upper and lower values of the enhancement factor were 18.7 and 63.0 for plutonium and 24.9 and 28.8 for americium. For americium, a default factor of 25 is proposed. This work demonstrates that the use of a default DTPA enhancement factor allows the determination of the magnitude of the contamination because dose estimated could vary by a factor of 2 depending on the value of the individual DTPA enhancement factor. In case of significant intake, an individual enhancement factor should be determined to obtain a more reliable dose assessment.

  10. Shuttle radiation dose measurements in the International Space Station orbits.

    PubMed

    Badhwar, Gautam D

    2002-01-01

    The International Space Station (ISS) is now a reality with the start of a permanent human presence on board. Radiation presents a serious risk to the health and safety of the astronauts, and there is a clear requirement for estimating their exposures prior to and after flights. Predictions of the dose rate at times other than solar minimum or solar maximum have not been possible, because there has been no method to calculate the trapped-particle spectrum at intermediate times. Over the last few years, a tissue-equivalent proportional counter (TEPC) has been flown at a fixed mid-deck location on board the Space Shuttle in 51.65 degrees inclination flights. These flights have provided data that cover the expected changes in the dose rates due to changes in altitude and changes in solar activity from the solar minimum to the solar maximum of the current 23rd solar cycle. Based on these data, a simple function of the solar deceleration potential has been derived that can be used to predict the galactic cosmic radiation (GCR) dose rates to within +/-10%. For altitudes to be covered by the ISS, the dose rate due to the trapped particles is found to be a power-law function, rho(-2/3), of the atmospheric density, rho. This relationship can be used to predict trapped dose rates inside these spacecraft to +/-10% throughout the solar cycle. Thus, given the shielding distribution for a location inside the Space Shuttle or inside an ISS module, this approach can be used to predict the combined GCR + trapped dose rate to better than +/-15% for quiet solar conditions.

  11. Radiation dose to patient and personnel during extracorporeal shock wave lithotripsy

    SciTech Connect

    Bush, W.H.; Jones, D.; Gibbons, R.P.

    1987-10-01

    Radiation dose to the patient and personnel was determined during extracorporeal shock wave lithotripsy treatment of 60 patients. Surface radiation dose to the patient's back from the fluoroscopy unit on the side with the kidney stone averaged 10 rem (100 mSv.) per case, although the range was wide (1 to 30 rem). The surface dose from the opposing biplane x-ray unit was less, averaging 5.5 rem (55 mSv.) per case but again with a wide range (0.1 to 21 rem). Exit dose at the lower abdomen averaged 13 mrem. (0.13 mSv.) per case and estimated female gonad dose averaged 100 mrem. (1.2 mSv.). Radiation dose to personnel working in the extracorporeal shock wave lithotripsy suite averaged less than 2 mrem. (0.02 mSv.) per case, making it a procedure that is safe in regard to radiation exposure.

  12. Concurrent image and dose reconstruction for image guided radiation therapy

    NASA Astrophysics Data System (ADS)

    Sheng, Ke

    The importance of knowing the patient actual position is essential for intensity modulated radiation therapy (IMRT). This procedure uses tightened margin and escalated tumor dose. In order to eliminate the uncertainty of the geometry in IMRT, daily imaging is prefered. The imaging dose, limited field of view and the imaging concurrency of the MVCT (mega-voltage computerized tomography) are investigated in this work. By applying partial volume imaging (PVI), imaging dose can be reduced for a region of interest (ROI) imaging. The imaging dose and the image quality are quantitatively balanced with inverse imaging dose planning. With PVI, 72% average imaging dose reduction was observed on a typical prostate patient case. The algebraic reconstruction technique (ART) based projection onto convex sets (POCS) shows higher robustness than filtered back projection when available imaging data is not complete and continuous. However, when the projection is continuous as in the actual delivery, a non-iterative wavelet based multiresolution local tomography (WMLT) is able to achieve 1% accuracy within the ROI. The reduction of imaging dose is dependent on the size of ROI. The improvement of concurrency is also discussed based on the combination of PVI and WMLT. Useful target images were acquired with treatment beams and the temporal resolution can be increased to 20 seconds in tomotherapy. The data truncation problem with the portal imager was also studied. Results show that the image quality is not adversely affected by truncation when WMLT is employed. When the online imaging is available, a perturbation dose calculation (PDC) that estimates the actual delivered dose is proposed. Corrected from the Fano's theorem, PDC counts the first order term in the density variation to calculate the internal and external anatomy change. Although change in the dose distribution that is caused by the internal organ motion is less than 1% for 6 MV beams, the external anatomy change has

  13. SYNCHROTRON RADIATION, FREE ELECTRON LASER, APPLICATION OF NUCLEAR TECHNOLOGY, ETC.: Measurement of radiation dose at the north interaction point of BEPC II

    NASA Astrophysics Data System (ADS)

    Mo, Xiao-Hu; Zhang, Jian-Yong; Zhang, Tian-Bao; Zhang, Qing-Jiang; Achasov, Mikhail; Fu, Cheng-Dong; Muchnoi, Nikolay; Qin, Qing; Qu, Hua-Min; Wang, Yi-Fang; Wu, Jing-Min; Xu, Jin-Qiang; Yu, Bo-Xiang

    2009-10-01

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

  14. Source term calculations for assessing radiation dose to equipment

    SciTech Connect

    Denning, R.S.; Freeman-Kelly, R.; Cybulskis, P.; Curtis, L.A.

    1989-07-01

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

  15. Measurement of dose in radionuclide therapy by using Cerenkov radiation.

    PubMed

    Ai, Yao; Tang, Xiaobin; Shu, Diyun; Shao, Wencheng; Gong, Chunhui; Geng, Changran; Zhang, Xudong; Yu, Haiyan

    2017-08-14

    This work aims to determine the relationship between Cerenkov photon emission and radiation dose from internal radionuclide irradiation. Water and thyroid phantoms were used to simulate the distribution of Cerenkov photon emission and dose deposition through Monte Carlo method. The relationship between Cerenkov photon emission and dose deposition was quantitatively analyzed. A neck phantom was also used to verify Cerenkov photon detection for thyroid radionuclide therapy. Results show that Cerenkov photon emission and dose deposition exhibit the same distribution pattern in water phantom, and this relative distribution relationship also existed in the thyroid phantom. Moreover, Cerenkov photon emission exhibits a specific quantitative relation to dose deposition. For thyroid radionuclide therapy, only a part of Cerenkov photon produced by thyroid could penetrate the body for detection; therefore, the use of Cerenkov radiation for measurement of radionuclide therapy dose may be more suitable for superficial tumors. This study demonstrated that Cerenkov radiation has the potential to be used for measuring radiation dose for radionuclide therapy.

  16. Effects of Chronic Low-Dose Radiation on Human Neural Progenitor Cells

    NASA Astrophysics Data System (ADS)

    Katsura, Mari; Cyou-Nakamine, Hiromasa; Zen, Qin; Zen, Yang; Nansai, Hiroko; Amagasa, Shota; Kanki, Yasuharu; Inoue, Tsuyoshi; Kaneki, Kiyomi; Taguchi, Akashi; Kobayashi, Mika; Kaji, Toshiyuki; Kodama, Tatsuhiko; Miyagawa, Kiyoshi; Wada, Youichiro; Akimitsu, Nobuyoshi; Sone, Hideko

    2016-01-01

    The effects of chronic low-dose radiation on human health have not been well established. Recent studies have revealed that neural progenitor cells are present not only in the fetal brain but also in the adult brain. Since immature cells are generally more radiosensitive, here we investigated the effects of chronic low-dose radiation on cultured human neural progenitor cells (hNPCs) derived from embryonic stem cells. Radiation at low doses of 31, 124 and 496 mGy per 72 h was administered to hNPCs. The effects were estimated by gene expression profiling with microarray analysis as well as morphological analysis. Gene expression was dose-dependently changed by radiation. By thirty-one mGy of radiation, inflammatory pathways involving interferon signaling and cell junctions were altered. DNA repair and cell adhesion molecules were affected by 124 mGy of radiation while DNA synthesis, apoptosis, metabolism, and neural differentiation were all affected by 496 mGy of radiation. These in vitro results suggest that 496 mGy radiation affects the development of neuronal progenitor cells while altered gene expression was observed at a radiation dose lower than 100 mGy. This study would contribute to the elucidation of the clinical and subclinical phenotypes of impaired neuronal development induced by chronic low-dose radiation.

  17. Effects of Chronic Low-Dose Radiation on Human Neural Progenitor Cells

    PubMed Central

    Katsura, Mari; Cyou-Nakamine, Hiromasa; Zen, Qin; Zen, Yang; Nansai, Hiroko; Amagasa, Shota; Kanki, Yasuharu; Inoue, Tsuyoshi; Kaneki, Kiyomi; Taguchi, Akashi; Kobayashi, Mika; Kaji, Toshiyuki; Kodama, Tatsuhiko; Miyagawa, Kiyoshi; Wada, Youichiro; Akimitsu, Nobuyoshi; Sone, Hideko

    2016-01-01

    The effects of chronic low-dose radiation on human health have not been well established. Recent studies have revealed that neural progenitor cells are present not only in the fetal brain but also in the adult brain. Since immature cells are generally more radiosensitive, here we investigated the effects of chronic low-dose radiation on cultured human neural progenitor cells (hNPCs) derived from embryonic stem cells. Radiation at low doses of 31, 124 and 496 mGy per 72 h was administered to hNPCs. The effects were estimated by gene expression profiling with microarray analysis as well as morphological analysis. Gene expression was dose-dependently changed by radiation. By thirty-one mGy of radiation, inflammatory pathways involving interferon signaling and cell junctions were altered. DNA repair and cell adhesion molecules were affected by 124 mGy of radiation while DNA synthesis, apoptosis, metabolism, and neural differentiation were all affected by 496 mGy of radiation. These in vitro results suggest that 496 mGy radiation affects the development of neuronal progenitor cells while altered gene expression was observed at a radiation dose lower than 100 mGy. This study would contribute to the elucidation of the clinical and subclinical phenotypes of impaired neuronal development induced by chronic low-dose radiation. PMID:26795421

  18. Effects of Chronic Low-Dose Radiation on Human Neural Progenitor Cells.

    PubMed

    Katsura, Mari; Cyou-Nakamine, Hiromasa; Zen, Qin; Zen, Yang; Nansai, Hiroko; Amagasa, Shota; Kanki, Yasuharu; Inoue, Tsuyoshi; Kaneki, Kiyomi; Taguchi, Akashi; Kobayashi, Mika; Kaji, Toshiyuki; Kodama, Tatsuhiko; Miyagawa, Kiyoshi; Wada, Youichiro; Akimitsu, Nobuyoshi; Sone, Hideko

    2016-01-22

    The effects of chronic low-dose radiation on human health have not been well established. Recent studies have revealed that neural progenitor cells are present not only in the fetal brain but also in the adult brain. Since immature cells are generally more radiosensitive, here we investigated the effects of chronic low-dose radiation on cultured human neural progenitor cells (hNPCs) derived from embryonic stem cells. Radiation at low doses of 31, 124 and 496 mGy per 72 h was administered to hNPCs. The effects were estimated by gene expression profiling with microarray analysis as well as morphological analysis. Gene expression was dose-dependently changed by radiation. By thirty-one mGy of radiation, inflammatory pathways involving interferon signaling and cell junctions were altered. DNA repair and cell adhesion molecules were affected by 124 mGy of radiation while DNA synthesis, apoptosis, metabolism, and neural differentiation were all affected by 496 mGy of radiation. These in vitro results suggest that 496 mGy radiation affects the development of neuronal progenitor cells while altered gene expression was observed at a radiation dose lower than 100 mGy. This study would contribute to the elucidation of the clinical and subclinical phenotypes of impaired neuronal development induced by chronic low-dose radiation.

  19. Measurements of the neutron dose equivalent for various radiation qualities, treatment machines and delivery techniques in radiation therapy.

    PubMed

    Hälg, R A; Besserer, J; Boschung, M; Mayer, S; Lomax, A J; Schneider, U

    2014-05-21

    In radiation therapy, high energy photon and proton beams cause the production of secondary neutrons. This leads to an unwanted dose contribution, which can be considerable for tissues outside of the target volume regarding the long term health of cancer patients. Due to the high biological effectiveness of neutrons in regards to cancer induction, small neutron doses can be important. This study quantified the neutron doses for different radiation therapy modalities. Most of the reports in the literature used neutron dose measurements free in air or on the surface of phantoms to estimate the amount of neutron dose to the patient. In this study, dose measurements were performed in terms of neutron dose equivalent inside an anthropomorphic phantom. The neutron dose equivalent was determined using track etch detectors as a function of the distance to the isocenter, as well as for radiation sensitive organs. The dose distributions were compared with respect to treatment techniques (3D-conformal, volumetric modulated arc therapy and intensity-modulated radiation therapy for photons; spot scanning and passive scattering for protons), therapy machines (Varian, Elekta and Siemens linear accelerators) and radiation quality (photons and protons). The neutron dose equivalent varied between 0.002 and 3 mSv per treatment gray over all measurements. Only small differences were found when comparing treatment techniques, but substantial differences were observed between the linear accelerator models. The neutron dose equivalent for proton therapy was higher than for photons in general and in particular for double-scattered protons. The overall neutron dose equivalent measured in this study was an order of magnitude lower than the stray dose of a treatment using 6 MV photons, suggesting that the contribution of the secondary neutron dose equivalent to the integral dose of a radiotherapy patient is small.

  20. Measurements of the neutron dose equivalent for various radiation qualities, treatment machines and delivery techniques in radiation therapy

    NASA Astrophysics Data System (ADS)

    Hälg, R. A.; Besserer, J.; Boschung, M.; Mayer, S.; Lomax, A. J.; Schneider, U.

    2014-05-01

    In radiation therapy, high energy photon and proton beams cause the production of secondary neutrons. This leads to an unwanted dose contribution, which can be considerable for tissues outside of the target volume regarding the long term health of cancer patients. Due to the high biological effectiveness of neutrons in regards to cancer induction, small neutron doses can be important. This study quantified the neutron doses for different radiation therapy modalities. Most of the reports in the literature used neutron dose measurements free in air or on the surface of phantoms to estimate the amount of neutron dose to the patient. In this study, dose measurements were performed in terms of neutron dose equivalent inside an anthropomorphic phantom. The neutron dose equivalent was determined using track etch detectors as a function of the distance to the isocenter, as well as for radiation sensitive organs. The dose distributions were compared with respect to treatment techniques (3D-conformal, volumetric modulated arc therapy and intensity-modulated radiation therapy for photons; spot scanning and passive scattering for protons), therapy machines (Varian, Elekta and Siemens linear accelerators) and radiation quality (photons and protons). The neutron dose equivalent varied between 0.002 and 3 mSv per treatment gray over all measurements. Only small differences were found when comparing treatment techniques, but substantial differences were observed between the linear accelerator models. The neutron dose equivalent for proton therapy was higher than for photons in general and in particular for double-scattered protons. The overall neutron dose equivalent measured in this study was an order of magnitude lower than the stray dose of a treatment using 6 MV photons, suggesting that the contribution of the secondary neutron dose equivalent to the integral dose of a radiotherapy patient is small.

  1. Contribution of maternal radionuclide burdens to prenatal radiation doses

    SciTech Connect

    Sikov, M.R.; Hui, T.E.; Meznarich, H.K.; Thrall, K.D. . Div. of Regulatory Applications); Traub, R.J. )

    1992-03-01

    This report discusses approaches to calculating and expressing radiation doses to the embryo/fetus from internal radionuclides. Information was obtained for selected, occupationally significant radionuclides in chemical forms that provided a spectrum of metabolic and dosimetric characteristics. Fractional placental transfer and/or ratios of concentration in the embryo/fetus to that in the woman were estimated for these materials, and were combined with data from biokinetic transfer models to predict radioactivity levels in the embryo/fetus as a function of stage of pregnancy and time after entry into the transfer compartment or blood of the pregnant woman. Medical Internal Radiation Dosimetry (MIRD) methodologies were extended to formalize and describe details for calculating radiation absorbed doses to the embryo/fetus. Calculations were performed for representative situations; introduction of 1 {mu}Ci into a woman's blood at successive months of pregnancy was assumed to accommodate the stage dependence of geometric relationships and biological behaviors. Summary tables of results, correlations, and dosimetric relations, and of tentative generalized categorizations, are provided in the report.

  2. Quality initiatives: CT radiation dose reduction: how to implement change without sacrificing diagnostic quality.

    PubMed

    Tamm, Eric P; Rong, X John; Cody, Dianna D; Ernst, Randy D; Fitzgerald, Nancy E; Kundra, Vikas

    2011-01-01

    The risks and benefits of using computed tomography (CT) as opposed to another imaging modality to accomplish a particular clinical goal should be weighed carefully. To accurately assess radiation risks and keep radiation doses as low as reasonably achievable, radiologists must be knowledgeable about the doses delivered during various types of CT studies performed at their institutions. The authors of this article propose a process improvement approach that includes the estimation of effective radiation dose levels, formulation of dose reduction goals, modification of acquisition protocols, assessment of effects on image quality, and implementation of changes necessary to ensure quality. A first step toward developing informed radiation dose reduction goals is to become familiar with the radiation dose values and radiation-associated health risks reported in the literature. Next, to determine the baseline dose values for a CT study at a particular institution, dose data can be collected from the CT scanners, interpreted, tabulated, and graphed. CT protocols can be modified to reduce overall effective dose by using techniques such as automated exposure control and iterative reconstruction, as well as by decreasing the number of scanning phases, increasing the section thickness, and adjusting the peak voltage (kVp setting), tube current-time product (milliampere-seconds), and pitch. Last, PDSA (plan, do, study, act) cycles can be established to detect and minimize negative effects of dose reduction methods on image quality.

  3. Organ doses received by atomic bomb survivors during radiological examinations at the Radiation Effects Research Foundation.

    PubMed

    Kazuo, K; Antoku, S; Sawada, S; Russell, W J

    1991-08-01

    When evaluating the risks of oncogenesis and cancer mortality following exposure to the radiations of the atomic bombs (A-bombs), the medical X-ray doses received by the A-bomb survivors must also be estimated and considered. Using a human phantom, dosimetry was performed to estimate the X-ray doses received by A-bomb survivors during medical examinations at the Radiation Effects Research Foundation (RERF) as part of the long-term follow-up on the Adult Health Study (AHS). These examinations have been estimated to represent nearly 45% of the survivors' cumulative medical irradiation dose. Doses to the salivary glands, thyroid gland, lung, breast, stomach and colon were measured using thermoluminescent dosimeters. The results, which are reported here, will aid in estimating organ doses received by individual AHS participants.

  4. Radiation doses to paediatric patients and comforters undergoing chest X rays.

    PubMed

    Sulieman, A; Vlychou, M; Tsougos, I; Theodorou, K

    2011-09-01

    Pneumonia is an important cause of hospital admission among children in the developed world and it is estimated to be responsible for 3-18 % of all paediatric admissions. Chest X ray is an important examination for pneumonia diagnosis and for evaluation of complications. This study aims to determine the entrance surface dose (ESD), organ, effective doses and propose a local diagnostic reference level. The study was carried out at the university hospital of Larissa, Greece. Patients were divided into three groups: organ and effective doses were estimated using National Radiological Protection Board software. The ESD was determined by thermoluminescent dosemeters for 132 children and 76 comforters. The average ESD value was 55 ± 8 µGy. The effective dose for patients was 11.2 ± 5 µSv. The mean radiation dose for comforter is 22 ± 3 µGy. The radiation dose to the patients is well within dose constraint, in the light of the current practice.

  5. Are Urologists Performing Semi-rigid Ureteroscopic Lithotripsy Safe From Radiation Exposure? A Guidance to Reduce the Radiation Dose.

    PubMed

    Kim, Chang Hee; Kim, Su Jin; Kim, Min Hoi; Kim, Kwang Tack; Oh, Jin Kyu; Chung, Kyung Jin; Kim, Tae Beom; Jung, Han; Yoon, Sang Jin; Kim, Khae Hawn

    2016-09-01

    To measure radiation exposure of urologists during ureteroscopic (URS) lithotripsy, and hence estimating the number of procedures that can be performed safely considering the annually permissible radiation dose, and to identify influential variables. The radiation exposure dose was measured at the neck, chest, arm, and hands of a single urologist who performed 49 URS lithotripsies. The number of annually performed URS lithotripsies was estimated based on the annual permissible occupational exposure radiation dose guidelines. The fluoroscopy screening time, tube voltage, and tube current were evaluated to determine their correlation with operative time, position, size, and Hounsfield unit (HU) values of the ureteral stones, and patients' body mass index (BMI). Our findings showed that 45 URS lithotripsies can be safely performed without a whole-body apron vs 1725 cases with one; considering the permissible dose for the hands, 448 cases without radiation protection were possible. Significant correlations were observed between operative time and fluoroscopy screening time (P < .001), ureteral calculi location and fluoroscopy screening time (P = .027), HU value and fluoroscopy screening time (P = .016), HU value and operative time (P = .041), and tube current and patients' BMI (P = .009). Considering radiation exposure risk, protective gear is necessary to ensure safety and efficacy of URS lithotripsy. Efforts to reduce radiation dose before and during surgery are required when ureteral calculi are in upper locations or have large HU, or the patient has a high BMI. Copyright © 2016. Published by Elsevier Inc.

  6. Digital radiography: image quality and radiation dose.

    PubMed

    Seibert, J Anthony

    2008-11-01

    Digital radiography devices, rapidly replacing analog screen-film detectors, are now common in diagnostic radiological imaging, where implementation has been accelerated by the commodity status of electronic imaging and display systems. The shift from narrow latitude, fixed-speed screen-film detectors to wide latitude, variable-speed digital detectors has created a flexible imaging system that can easily result in overexposures to the patient without the knowledge of the operator, thus potentially increasing the radiation burden of the patient population from radiographic examinations. In addition, image processing can be inappropriately applied causing inconsistent or artifactual appearance of anatomy, which can lead to misdiagnosis. On the other hand, many advantages can be obtained from the variable-speed digital detector, such as an ability to lower dose in many examinations, image post-processing for disease-specific conditions, display flexibility to change the appearance of the image and aid the physician in making a differential diagnosis, and easy access to digital images. An understanding of digital radiography is necessary to minimize the possibility of overexposures and inconsistent results, and to achieve the principle of as low as reasonably achievable (ALARA) for the safe and effective care of all patients. Thus many issues must be considered for optimal implementation of digital radiography, as reviewed in this article.

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

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

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

    NASA Technical Reports Server (NTRS)

    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.

  10. CARCINOGENIC EFFECTS OF LOW DOSES OF IONIZING RADIATION

    EPA Science Inventory

    Carcinogenic Effects of Low Doses of Ionizing Radiation

    R Julian Preston, Environmental Carcinogenesis Division, NHEERL, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

    The form of the dose-response curve for radiation-induced cancers, particu...

  11. CARCINOGENIC EFFECTS OF LOW DOSES OF IONIZING RADIATION

    EPA Science Inventory

    Carcinogenic Effects of Low Doses of Ionizing Radiation

    R Julian Preston, Environmental Carcinogenesis Division, NHEERL, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

    The form of the dose-response curve for radiation-induced cancers, particu...

  12. Biological-Based Modeling of Low Dose Radiation Risks

    SciTech Connect

    Scott, Bobby R., Ph.D.

    2006-11-08

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

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

    SciTech Connect

    Huda, W.

    1986-12-01

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

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

    PubMed

    Abdelhady, Amr

    2016-09-01

    The evaluation of the radiation dose during accident in a nuclear reactor is of great concern from the viewpoint of safety. One of important accident must be analyzed and may be occurred in open pool type reactor is the rejection of cobalt device. The study is evaluating the dose rate levels resulting from upset withdrawal of co device especially the radiation dose received by the operator in the control room. Study of indirect radiation exposure to the environment due to skyshine effect is also taken into consideration in order to evaluate the radiation dose levels around the reactor during the ejection trip. Microshield, SHLDUTIL, and MCSky codes were used in this study to calculate the radiation dose profiles during cobalt device ejection trip inside and outside the reactor building. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Radiation dose reduction in multidetector CT in fracture evaluation.

    PubMed

    Yi, Jung Woo; Park, Hee Jin; Lee, So Yeon; Rho, Myung Ho; Hong, Hyun Pyo; Choi, Yoon Jung; Kim, Mi Sung

    2017-08-01

    To evaluate whether multidetector CT with low-dose radiation (low-dose CT) of joints can be useful when evaluating fractures. Our study included CT scans of 398 patients, 103 shoulder cases, 109 wrist cases, 98 pelvis cases and 88 ankle cases. There were 191 females and 207 males. The low-dose CTs were performed using identical voltage and parameters with the exception of decreased (half of standard dose) tube current. Low-dose and standard-dose images were compared with regards to objective image quality, subjective evaluation of image quality and diagnostic performance for the fractures. There was no significant difference of image noise between standard-dose CT and low-dose CT in every joint (p > 0.05). Each mean value of subjective score did not show significant difference according to the dosage of the CT scan. There were no statistically significant differences in the sensitivity (96-100%), specificity (95.2-100%) or accuracy (97.9-100%) between standard-dose CT and low-dose CT (p values, 0.1336-1.000). The evaluation of extremities for fractures using low-dose CT can reduce radiation exposure by about 50% compared with standard-dose CT without affecting image quality or diagnostic performance. Advances in knowledge: Low-dose CT of the extremities (shoulder, pelvis, ankle and wrist) can reduce radiation dose by about 50% compared with standard-dose CT and does not significantly affect image quality or diagnostic performance in fracture detection.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  17. Radiation Doses of Various CT Protocols: a Multicenter Longitudinal Observation Study

    PubMed Central

    2016-01-01

    Emerging concerns regarding the hazard from medical radiation including CT examinations has been suggested. The purpose of this study was to observe the longitudinal changes of CT radiation doses of various CT protocols and to estimate the long-term efforts of supervising radiologists to reduce medical radiation. Radiation dose data from 11 representative CT protocols were collected from 12 hospitals. Attending radiologists had collected CT radiation dose data in two time points, 2007 and 2010. They collected the volume CT dose index (CTDIvol) of each phase, number of phases, dose length product (DLP) of each phase, and types of scanned CT machines. From the collected data, total DLP and effective dose (ED) were calculated. CTDIvol, total DLP, and ED of 2007 and 2010 were compared according to CT protocols, CT machine type, and hospital. During the three years, CTDIvol had significantly decreased, except for dynamic CT of the liver. Total DLP and ED were significantly decreased in all 11 protocols. The decrement was more evident in newer CT scanners. However, there was substantial variability of changes of ED during the three years according to hospitals. Although there was variability according to protocols, machines, and hospital, CT radiation doses were decreased during the 3 years. This study showed the effects of decreased CT radiation dose by efforts of radiologists and medical society. PMID:26908984

  18. Second Solid Cancers After Radiation Therapy: A Systematic Review of the Epidemiologic Studies of the Radiation Dose-Response Relationship

    SciTech Connect

    Berrington de Gonzalez, Amy; Gilbert, Ethel; Curtis, Rochelle; Inskip, Peter; Kleinerman, Ruth; Morton, Lindsay; Rajaraman, Preetha; Little, Mark P.

    2013-06-01

    Rapid innovations in radiation therapy techniques have resulted in an urgent need for risk projection models for second cancer risks from high-dose radiation exposure, because direct observation of the late effects of newer treatments will require patient follow-up for a decade or more. However, the patterns of cancer risk after fractionated high-dose radiation are much less well understood than those after lower-dose exposures (0.1-5 Gy). In particular, there is uncertainty about the shape of the dose-response curve at high doses and about the magnitude of the second cancer risk per unit dose. We reviewed the available evidence from epidemiologic studies of second solid cancers in organs that received high-dose exposure (>5 Gy) from radiation therapy where dose-response curves were estimated from individual organ-specific doses. We included 28 eligible studies with 3434 second cancer patients across 11 second solid cancers. Overall, there was little evidence that the dose-response curve was nonlinear in the direction of a downturn in risk, even at organ doses of ≥60 Gy. Thyroid cancer was the only exception, with evidence of a downturn after 20 Gy. Generally the excess relative risk per Gray, taking account of age and sex, was 5 to 10 times lower than the risk from acute exposures of <2 Gy among the Japanese atomic bomb survivors. However, the magnitude of the reduction in risk varied according to the second cancer. The results of our review provide insights into radiation carcinogenesis from fractionated high-dose exposures and are generally consistent with current theoretical models. The results can be used to refine the development of second solid cancer risk projection models for novel radiation therapy techniques.

  19. Peripheral Blood Lymphocytes as In Vitro Model to Evaluate Genomic Instability Caused by Low Dose Radiation.

    PubMed

    Tewari, Shikha; Khan, Kainat; Husain, Nuzhat; Rastogi, Madhup; Mishra, Surendra P; Srivastav, Anoop K

    2016-01-01

    Diagnostic and therapeutic radiation fields are planned so as to reduce side-effects while maximising the dose to site but effects on healthy tissues are inevitable. Radiation causes strand breaks in DNA of exposed cells which can lead to chromosomal aberrations and cause malfunction and cell death. Several researchers have highlighted the damaging effects of high dose radiation but still there is a lacuna in identifying damage due to low dose radiation used for diagnostic purposes. Blood is an easy resource to study genotoxicity and to estimate the effects of radiation. The micronucleus assay and chromosomal aberration can indicate genetic damage and our present aim was to establish these with lymphocytes in an in vitro model to predict the immediate effects low dose radiation. Blood was collected from healthy individuals and divided into 6 groups with increasing radiation dose i.e., 0Gy, 0.10Gy, 0.25Gy, 0.50Gy, 1Gy and 2Gy. The samples were irradiated in duplicates using a LINAC in the radiation oncology department. Standard protocols were applied for chromosomal aberration and micronucleus assays. Metaphases were stained in Giemsa and 200 were scored per sample for the detection of dicentric or acentric forms. For micronuclei detection, 200 metaphases. Giemsa stained binucleate cells per sample were analysed for any abnormality. The micronuclei (MN) frequency was increased in cells exposed to the entire range of doses (0.1- 2Gy) delivered. Controls showed minimal MN formation (2.0%±0.05) with triple MN (5.6%±2.0) frequency at the lowest dose. MN formation increased exponentially with the radiation dose thereafter with a maximum at 2Gy. Significantly elevated numbers of dicentric chromosomes were also observed, even at doses of 0.1- 0.5Gy, compared to controls, and acentric chromosomes were apparent at 2Gy. In conclusion we can state that lymphocytes can be effectively used to study direct effect of low dose radiation.

  20. [Evaluation of absorbed doses of ionizing radiation by milk teeth enamel in children living in the Belarus Republic].

    PubMed

    Mel'nichenko, E M; Kushner, A N; Miliutin, A A; Mashevskiĭ, A A; Muravskiĭ, V A

    2002-01-01

    Mean doses of ionizing radiation, absorbed by children in the Byelarus Republic, were evaluated by EPR dosimetry of tableted samples of milk teeth enamel. A relationship between the doses absorbed by the children and density of radionuclide contamination of the territory of residence was detected. Based on the mean absorbed doses, doses which can be absorbed during 70 years of life were estimated.

  1. Impact of dose and volume on radiation-induced mucositis.

    PubMed

    Mantini, Giovanna; Manfrida, Stefania; Cellini, Francesco; Giammarino, Daniela; Petrone, Adelina; Vitucci, Pasquale; Cellini, Numa

    2005-01-01

    There is a relationship between a given radiation dose and the resulting biological effect in the management of head and neck cancer. Radiation mucositis represents a frequent complication in cancer chemoradiation. Its prevention and treatment are major goals in radiation therapy schedules. Critical tissues can be spared using high conformal radiation therapy (3DCRT) based on consensus guidelines for target volume. Current approaches to radiation mucositis with respect to the dose and volume impact are illustrated. The monitoring system of late toxicity used by the authors is presented.

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

    SciTech Connect

    Friend, P.J.

    1991-12-31

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

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

    NASA Astrophysics Data System (ADS)

    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).

  4. Radiation doses from Hanford Site releases to the atmosphere and the Columbia River.

    PubMed

    Farris, W T; Napier, B A; Ikenberry, T A; Shipler, D B

    1996-10-01

    Radiation doses to individuals were estimated for the years 1944-1992 as part of the Hanford Dose Reconstruction Project (HEDR). The dose estimates were based on the radioactive releases to the atmosphere and Columbia River from the Hanford Site in southcentral Washington State. Conceptual models, computer codes, and previously published dose estimates were used to reconstruct doses. The most significant exposure pathway was found to be the consumption of cow's milk containing 131I. The median cumulative dose estimates to the thyroid of children ranged from < 0.7 mGy to 2.3 Gy throughout the study area, depending upon residence location. The highest estimated cumulative dose to a child ranged from 0.6-8.4 Gy (5th and 95th percentiles) with a median of 2.3 Gy based on 100 Monte Carlo realizations. The geographic distribution of the dose levels was directly related to the pattern of 131I deposition and was affected by the distribution of commercial milk and leafy vegetables. For the atmospheric pathway, the highest cumulative effective dose equivalent to an adult was estimated to be 12 mSv at Ringold, Washington, for the period 1944-1992. For the Columbia River pathway, cumulative effective dose equivalent estimates ranged from < 5 mSv to 15 mSv cumulative dose to maximally exposed adults downriver from the Hanford Site for the years 1944-1992. The most significant river exposure pathway was consumption of resident fish containing 32P and 65Zn.

  5. Offsite radiation doses summarized from Hanford environmental monitoring reports for the years 1957-1984. [Contains glossary

    SciTech Connect

    Soldat, J.K.; Price, K.R.; McCormack, W.D.

    1986-02-01

    Since 1957, evaluations of offsite impacts from each year of operation have been summarized in publicly available, annual environmental reports. These evaluations included estimates of potential radiation exposure to members of the public, either in terms of percentages of the then permissible limits or in terms of radiation dose. The estimated potential radiation doses to maximally exposed individuals from each year of Hanford operations are summarized in a series of tables and figures. The applicable standard for radiation dose to an individual for whom the maximum exposure was estimated is also shown. Although the estimates address potential radiation doses to the public from each year of operations at Hanford between 1957 and 1984, their sum will not produce an accurate estimate of doses accumulated over this time period. The estimates were the best evaluations available at the time to assess potential dose from the current year of operation as well as from any radionuclides still present in the environment from previous years of operation. There was a constant striving for improved evaluation of the potential radiation doses received by members of the public, and as a result the methods and assumptions used to estimate doses were periodically modified to add new pathways of exposure and to increase the accuracy of the dose calculations. Three conclusions were reached from this review: radiation doses reported for the years 1957 through 1984 for the maximum individual did not exceed the applicable dose standards; radiation doses reported over the past 27 years are not additive because of the changing and inconsistent methods used; and results from environmental monitoring and the associated dose calculations reported over the 27 years from 1957 through 1984 do not suggest a significant dose contribution from the buildup in the environment of radioactive materials associated with Hanford operations.

  6. Displaying 3D radiation dose on endoscopic video for therapeutic assessment and surgical guidance

    NASA Astrophysics Data System (ADS)

    Qiu, Jimmy; Hope, Andrew J.; Cho, B. C. John; Sharpe, Michael B.; Dickie, Colleen I.; DaCosta, Ralph S.; Jaffray, David A.; Weersink, Robert A.

    2012-10-01

    We have developed a method to register and display 3D parametric data, in particular radiation dose, on two-dimensional endoscopic images. This registration of radiation dose to endoscopic or optical imaging may be valuable in assessment of normal tissue response to radiation, and visualization of radiated tissues in patients receiving post-radiation surgery. Electromagnetic sensors embedded in a flexible endoscope were used to track the position and orientation of the endoscope allowing registration of 2D endoscopic images to CT volumetric images and radiation doses planned with respect to these images. A surface was rendered from the CT image based on the air/tissue threshold, creating a virtual endoscopic view analogous to the real endoscopic view. Radiation dose at the surface or at known depth below the surface was assigned to each segment of the virtual surface. Dose could be displayed as either a colorwash on this surface or surface isodose lines. By assigning transparency levels to each surface segment based on dose or isoline location, the virtual dose display was overlaid onto the real endoscope image. Spatial accuracy of the dose display was tested using a cylindrical phantom with a treatment plan created for the phantom that matched dose levels with grid lines on the phantom surface. The accuracy of the dose display in these phantoms was 0.8-0.99 mm. To demonstrate clinical feasibility of this approach, the dose display was also tested on clinical data of a patient with laryngeal cancer treated with radiation therapy, with estimated display accuracy of ˜2-3 mm. The utility of the dose display for registration of radiation dose information to the surgical field was further demonstrated in a mock sarcoma case using a leg phantom. With direct overlay of radiation dose on endoscopic imaging, tissue toxicities and tumor response in endoluminal organs can be directly correlated with the actual tissue dose, offering a more nuanced assessment of normal tissue

  7. Displaying 3D radiation dose on endoscopic video for therapeutic assessment and surgical guidance.

    PubMed

    Qiu, Jimmy; Hope, Andrew J; Cho, B C John; Sharpe, Michael B; Dickie, Colleen I; DaCosta, Ralph S; Jaffray, David A; Weersink, Robert A

    2012-10-21

    We have developed a method to register and display 3D parametric data, in particular radiation dose, on two-dimensional endoscopic images. This registration of radiation dose to endoscopic or optical imaging may be valuable in assessment of normal tissue response to radiation, and visualization of radiated tissues in patients receiving post-radiation surgery. Electromagnetic sensors embedded in a flexible endoscope were used to track the position and orientation of the endoscope allowing registration of 2D endoscopic images to CT volumetric images and radiation doses planned with respect to these images. A surface was rendered from the CT image based on the air/tissue threshold, creating a virtual endoscopic view analogous to the real endoscopic view. Radiation dose at the surface or at known depth below the surface was assigned to each segment of the virtual surface. Dose could be displayed as either a colorwash on this surface or surface isodose lines. By assigning transparency levels to each surface segment based on dose or isoline location, the virtual dose display was overlaid onto the real endoscope image. Spatial accuracy of the dose display was tested using a cylindrical phantom with a treatment plan created for the phantom that matched dose levels with grid lines on the phantom surface. The accuracy of the dose display in these phantoms was 0.8-0.99 mm. To demonstrate clinical feasibility of this approach, the dose display was also tested on clinical data of a patient with laryngeal cancer treated with radiation therapy, with estimated display accuracy of ∼2-3 mm. The utility of the dose display for registration of radiation dose information to the surgical field was further demonstrated in a mock sarcoma case using a leg phantom. With direct overlay of radiation dose on endoscopic imaging, tissue toxicities and tumor response in endoluminal organs can be directly correlated with the actual tissue dose, offering a more nuanced assessment of normal tissue

  8. 324 Building life cycle dose estimates for planned work

    SciTech Connect

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

    1995-09-01

    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.

  9. Dosimetry for a study of low-dose radiation cataracts among Chernobyl clean-up workers.

    PubMed

    Chumak, V V; Worgul, B V; Kundiyev, Y I; Sergiyenko, N M; Vitte, P M; Medvedovsky, C; Bakhanova, E V; Junk, A K; Kyrychenko, O Y; Musijachenko, N V; Sholom, S V; Shylo, S A; Vitte, O P; Xu, S; Xue, X; Shore, R E

    2007-05-01

    A cohort of 8,607 Ukrainian Chernobyl clean-up workers during 1986-1987 was formed to study cataract formation after ionizing radiation exposure. Study eligibility required the availability of sufficient exposure information to permit the reconstruction of doses to the lens of the eye. Eligible groups included civilian workers, such as those who built the "sarcophagus" over the reactor, Chernobyl Nuclear Power Plant Workers, and military reservists who were conscripted for clean-up work. Many of the official doses for workers were estimates, because only a minority wore radiation badges. For 106 military workers, electron paramagnetic resonance (EPR) measurements of extracted teeth were compared with the recorded doses as the basis to adjust the recorded gamma-ray doses and provide estimates of uncertainties. Beta-particle doses to the lens were estimated with an algorithm devised to take into account the nature and location of Chernobyl work, time since the accident, and protective measures taken. A Monte Carlo routine generated 500 random estimates for each individual from the uncertainty distributions of the gamma-ray dose and of the ratio of beta-particle to gamma-ray doses. The geometric mean of the 500 combined beta-particle and gamma-ray dose estimates for each individual was used in the data analyses. The median estimated lens dose for the cohort was 123 mGy, while 4.4% received >500 mGy.

  10. Total dose performance of radiation hardened voltage regulators and references

    NASA Technical Reports Server (NTRS)

    McClure, S.; Gorelick, J.; Pease, R.; Rax, B.; Ladbury, R.

    2001-01-01

    Total dose test of commercially available radiation hardened bipolar voltage regulators and references show reduced sensitivity to dose rate and varying sensitivity to bias under pressure. Behavior of critical parameters in different dose rate and bias conditions is compared and the impact to hardness assurance methodology is discussed.

  11. WE-A-18A-01: TG246 On Patient Dose From Diagnostic Radiation

    SciTech Connect

    Supanich, M; Dong, F; Andersson, J; Pavlicek, W; Bolch, W; Fetterly, K

    2014-06-15

    Radiation dose from diagnostic and interventional radiations continues to be a focus of the regulatory, accreditation and standards organizations in the US and Europe. A Joint AAPM/EFOMP effort has been underway in the past year — having the goal to assist the clinical medical physicist with communicating optional and varied approaches in estimating (and validating) patient dose. In particular, the tools provided by DICOM Radiation Dose Structured Reports, either by themselves or as part of a networked data repository of dose related information are a rich source of actionable information. The tools of the medical physicist have evolved to include using DICOM data in meaningful ways to look at patient dose with respect to imaging practices. In addition to how accurate or reproducible a dose value is (totally necessary and our traditional workspace) it is now being asked how reproducible (patient to patient, device to device) are the delivered doses (new tasking)? Clinical medical physicists are best equipped to assist our radiology and technologist colleagues with this effort. The purpose of this session is to review the efforts of TG246 - bringing forward a summary content of the TG246 Report including specific dose descriptors for CT and Fluoroscopy — particularly in a focus of leveraging the RDSR as a means for monitoring good practices ALARA. Additionally, rapidly evolving technologies for more refined dose estimates are now in use. These will be presented as they look to having highly patient specific dose estimates in automated use.

  12. Radiation damage in single-particle cryo-electron microscopy: effects of dose and dose rate

    PubMed Central

    Karuppasamy, Manikandan; Karimi Nejadasl, Fatemeh; Vulovic, Milos; Koster, Abraham J.; Ravelli, Raimond B. G.

    2011-01-01

    Radiation damage is an important resolution limiting factor both in macromolecular X-ray crystallography and cryo-electron microscopy. Systematic studies in macromolecular X-ray crystallography greatly benefited from the use of dose, expressed as energy deposited per mass unit, which is derived from parameters including incident flux, beam energy, beam size, sample composition and sample size. In here, the use of dose is reintroduced for electron microscopy, accounting for the electron energy, incident flux and measured sample thickness and composition. Knowledge of the amount of energy deposited allowed us to compare doses with experimental limits in macromolecular X-ray crystallography, to obtain an upper estimate of radical concentrations that build up in the vitreous sample, and to translate heat-transfer simulations carried out for macromolecular X-ray crystallography to cryo-electron microscopy. Stroboscopic exposure series of 50–250 images were collected for different incident flux densities and integration times from Lumbricus terrestris extracellular hemoglobin. The images within each series were computationally aligned and analyzed with similarity metrics such as Fourier ring correlation, Fourier ring phase residual and figure of merit. Prior to gas bubble formation, the images become linearly brighter with dose, at a rate of approximately 0.1% per 10 MGy. The gradual decomposition of a vitrified hemoglobin sample could be visualized at a series of doses up to 5500 MGy, by which dose the sample was sublimed. Comparison of equal-dose series collected with different incident flux densities showed a dose-rate effect favoring lower flux densities. Heat simulations predict that sample heating will only become an issue for very large dose rates (50 e−Å−2 s−1 or higher) combined with poor thermal contact between the grid and cryo-holder. Secondary radiolytic effects are likely to play a role in dose-rate effects. Stroboscopic data collection

  13. Dose reconstruction for real-time patient-specific dose estimation in CT

    SciTech Connect

    De Man, Bruno Yin, Zhye; Wu, Mingye; FitzGerald, Paul; Kalra, Mannudeep

    2015-05-15

    Purpose: Many recent computed tomography (CT) dose reduction approaches belong to one of three categories: statistical reconstruction algorithms, efficient x-ray detectors, and optimized CT acquisition schemes with precise control over the x-ray distribution. The latter category could greatly benefit from fast and accurate methods for dose estimation, which would enable real-time patient-specific protocol optimization. Methods: The authors present a new method for volumetrically reconstructing absorbed dose on a per-voxel basis, directly from the actual CT images. The authors’ specific implementation combines a distance-driven pencil-beam approach to model the first-order x-ray interactions with a set of Gaussian convolution kernels to model the higher-order x-ray interactions. The authors performed a number of 3D simulation experiments comparing the proposed method to a Monte Carlo based ground truth. Results: The authors’ results indicate that the proposed approach offers a good trade-off between accuracy and computational efficiency. The images show a good qualitative correspondence to Monte Carlo estimates. Preliminary quantitative results show errors below 10%, except in bone regions, where the authors see a bigger model mismatch. The computational complexity is similar to that of a low-resolution filtered-backprojection algorithm. Conclusions: The authors present a method for analytic dose reconstruction in CT, similar to the techniques used in radiation therapy planning with megavoltage energies. Future work will include refinements of the proposed method to improve the accuracy as well as a more extensive validation study. The proposed method is not intended to replace methods that track individual x-ray photons, but the authors expect that it may prove useful in applications where real-time patient-specific dose estimation is required.

  14. Temporal variability patterns in solar radiation estimations

    NASA Astrophysics Data System (ADS)

    Vindel, José M.; Navarro, Ana A.; Valenzuela, Rita X.; Zarzalejo, Luis F.

    2016-06-01

    In this work, solar radiation estimations obtained from a satellite and a numerical weather prediction model in mainland Spain have been compared. Similar comparisons have been formerly carried out, but in this case, the methodology used is different: the temporal variability of both sources of estimation has been compared with the annual evolution of the radiation associated to the different study climate zones. The methodology is based on obtaining behavior patterns, using a Principal Component Analysis, following the annual evolution of solar radiation estimations. Indeed, the adjustment degree to these patterns in each point (assessed from maps of correlation) may be associated with the annual radiation variation (assessed from the interquartile range), which is associated, in turn, to different climate zones. In addition, the goodness of each estimation source has been assessed comparing it with data obtained from the radiation measurements in ground by pyranometers. For the study, radiation data from Satellite Application Facilities and data corresponding to the reanalysis carried out by the European Centre for Medium-Range Weather Forecasts have been used.

  15. Influence of organs in the ICRP's remainder on effective dose equivalent computed for diagnostic radiation exposures

    SciTech Connect

    Gibbs, S.J.

    1989-04-01

    The ICRP effective dose equivalent has been compared with a weighted dose equivalent, computed by treating the entire remainder instead of the sample of five remainder organs in the ICRP method as uniformly radiosensitive, for dose distributions from three common diagnostic exposures: chest, dental full-mouth and dental panoramic. Complete dose distributions were computed by a Monte Carlo model. In all three cases the effective dose equivalent was greater than the weighted dose equivalent. The difference was only 20% for the chest exam but was more than fivefold for both dental exposures. Dose distributions for the dental exposures were less homogeneous than for the chest examination. Selection of organs to be included in the remainder markedly affects the effective dose equivalent. In the case of highly inhomogeneous dose distributions, the effective dose equivalent probably significantly over-estimates radiation detriment.

  16. Radiation dose to the respiratory airway linings from inhalation of (/sup 15/O)-carbon dioxide

    SciTech Connect

    Bigler, R.E.; Sgouros, G.; Zanzonico, P.B.; Cosma, M.; Leonard, R.W.; Dahl, J.R.

    1985-05-01

    Estimates of the radiation dose to the upper airways including the trachea, oropharnyx, and nasal linings from inhalation of oxygen-15 labeled CO/sub 2/ studies are provided. Three air administration procedures were examined; inhalation by nose, by mouth and by mouth through a mouthpiece. Attention is given to the inhaled radioactive gas absorbed and retained in the mucus and saliva layers lining the respiratory passages. The author