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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. 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. PMID:26581473

  3. 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.

  4. 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.

  5. 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. PMID:11537609

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

    NASA Astrophysics Data System (ADS)

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

    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°, 57° and 90°) 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° orbital inclination.

  7. Radiation dose estimation of patients undergoing lumbar spine radiography

    PubMed Central

    Gyekye, Prince Kwabena; Simon, Adu; Geoffrey, Emi-Reynolds; Johnson, Yeboah; Stephen, Inkoom; Engmann, Cynthia Kaikor; Samuel, Wotorchi-Gordon

    2013-01-01

    Radiation dose to organs of 100 adult patients undergoing lumbar spine (LS) radiography at a University Hospital have been assessed. Free in air kerma measurement using an ionization chamber was used for the patient dosimetry. Organ and effective dose to the patients were estimated using PCXMC (version 1.5) software. The organs that recorded significant dose due to LS radiography were lungs, stomach, liver, adrenals, kidney, pancreas, spleen, galbladder, and the heart. It was observed that the stomach recorded the highest dose (48.2 ± 1.2 μGy) for LS anteroposterior (AP). The spleen also recorded the highest dose (41.2 ± 0.5 μGy) for LS lateral (LAT). The mean entrance surface air kerma (ESAK) of LS LAT (122.2 μGy) was approximately twice that of LS AP (76.3 μGy), but the effective dose for both examinations were approximately the same (LS LAT = 8.6 μSv and LS AP = 10.4 μSv). The overall stochastic health effect of radiation to patients due to LS radiography in the University Hospital is independent of the projection of the examination (AP or LAT). PMID:24672153

  8. 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

  9. Radiation Dose Estimation Using Realistic Postures with PIMAL

    SciTech Connect

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

    2010-12-01

    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.

  10. 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.

  11. 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. PMID:26435777

  12. 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

  13. 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

  14. 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. PMID:22247630

  15. 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

  16. Space radiation dose estimates on the surface of Mars

    NASA Astrophysics Data System (ADS)

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

    1990-08-01

    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.

  17. 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.

  18. 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

  19. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    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 KMnO4 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 μSv/year and 0.532 μSv/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 μSv/year.

  1. Estimation of background radiation doses for the Peninsular Malaysia's population by ESR dosimetry of tooth enamel.

    PubMed

    Rodzi, Mohd; Zhumadilov, Kassym; Ohtaki, Megu; Ivannikov, Alexander; Bhattacharjee, Deborshi; Fukumura, Akifumi; Hoshi, Masaharu

    2011-08-01

    Background radiation dose is used in dosimetry for estimating occupational doses of radiation workers or determining radiation dose of an individual following accidental exposure. In the present study, the absorbed dose and the background radiation level are determined using the electron spin resonance (ESR) method on tooth samples. The effect of using different tooth surfaces and teeth exposed with single medical X-rays on the absorbed dose are also evaluated. A total of 48 molars of position 6-8 were collected from 13 district hospitals in Peninsular Malaysia. Thirty-six teeth had not been exposed to any excessive radiation, and 12 teeth had been directly exposed to a single X-ray dose during medical treatment prior to extraction. There was no significant effect of tooth surfaces and exposure with single X-rays on the measured absorbed dose of an individual. The mean measured absorbed dose of the population is 34 ± 6.2 mGy, with an average tooth enamel age of 39 years. From the slope of a regression line, the estimated annual background dose for Peninsular Malaysia is 0.6 ± 0.3 mGy y(-1). This value is slightly lower than the yearly background dose for Malaysia, and the radiation background dose is established by ESR tooth measurements on samples from India and Russia. PMID:21404066

  2. Estimation of radiation absorbed doses to the red marrow in radioimmunotherapy

    SciTech Connect

    Macey, D.J.; DeNardo, S.J.; DeNardo, G.L.; DeNardo, D.A.; Sui Shen

    1995-02-01

    Myelotoxicity is the dose-limiting factor in radioimmunotherapy. Traditional methods most commonly used to estimate the radiation adsorbed dose to the bone marrow of patients consider contribution from radionuclide in the blood and/or total body. Targeted therapies, such as radioimmunotherapy, add a third potential source for radiation to the bone marrow because the radiolabeled targeting molecules can accumulate specifically on malignant target cells infiltrating the bone marrow. A non-invasive method for estimating the radiation absorbed dose to the red marrow of patients who have received radiolabeled monoclonal antibodies (MoAb) has been developed and explored. The method depends on determining the cumulated activity in three contributing sources: (1) marrow; (2) blood; and (3) total body. The novel aspect of this method for estimating marrow radiation dose is derivation of the radiation dose for the entire red marrow from radiation dose estimates obtained by detection of cumulated activity in three lumbar vertebrae using a gamma camera. Contributions to the marrow radiation dose form marrow, blood, and total body cumulated activity were determined for patients who received an I-131 labeled MoAb, Lym-1, that reacts with malignant B-lymphocytes of chronic lymphocytic leukemia and nonHodgkin`s lymphoma. Six patients were selected for illustrative purposes because their vertebrae were readily visualized on lumbar images. 32 refs., 6 figs., 1 tab.

  3. 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. PMID:21969661

  4. 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. PMID:10214706

  5. 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. PMID:25539270

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

    PubMed

    Morishima, Yoshiaki; Chida, Koichi; Watanabe, Hiroshi

    2016-08-01

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

  7. 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.

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

    SciTech Connect

    Not Available

    1983-12-01

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

  9. 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.

  10. 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...

  11. 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 ...

  12. 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.

  13. 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.

  14. Estimation of radiation dose received by the radiation worker during F-18 FDG injection process

    PubMed Central

    Jha, Ashish Kumar; Zade, Anand; Rangarajan, Venkatesh

    2011-01-01

    Background: The radiation dosimetric literature concerning the medical and non-medical personnel working in nuclear medicine departments are limited, particularly radiation doses received by radiation worker in nuclear medicine department during positron emission tomography (PET) radiopharmaceutical injection process. This is of interest and concern for the personnel. Aim: To measure the radiation dose received by the staff involved in injection process of Fluorine-18 Fluorodeoxyglucose (FDG). Materials and Methods: The effective whole body doses to the radiation workers involved in injections of 1511 patients over a period of 10 weeks were evaluated using pocket dosimeter. Each patient was injected with 5 MBq/kg of F-18 FDG. The F18-FDG injection protocol followed in our department is as follows. The technologist dispenses the dose to be injected and records the pre-injection activity. The nursing staff members then secure an intravenous catheter. The nuclear medicine physicians/residents inject the dose on a rotation basis in accordance with ALARA principle. After the injection of the tracer, the nursing staff members flush the intravenous catheter. The person who injected the tracer then measures the post-injection residual dose in the syringe. Results: The mean effective whole body doses per injection for the staff were the following: Nurses received 1.44±0.22 μSv/injection (3.71±0.48 nSv/MBq), for doctors the dose values were 2.44±0.25 μSv/injection (6.29±0.49 nSv/MBq) and for technologists the doses were 0.61±0.10 μSv/injection (1.58±0.21 nSv/MBq). It was seen that the mean effective whole body dose per injection of our positron emission tomography/computed tomography (PET/CT) staff who were involved in the F18-FDG injection process was maximum for doctors (54.34% differential doses), followed by nurses (32.02% differential doses) and technologist (13.64% differential doses). Conclusion: This study confirms that low levels of radiation dose are

  15. 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

    2016-01-01

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

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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

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

    PubMed

    Ng, Y C; Anspaugh, L R; Cederwall, R T

    1990-11-01

    A method was developed to reconstruct the internal radiation dose to off-site individuals who were exposed to fallout from nuclear weapons tests at the Nevada Test Site (NTS). By this method, committed absorbed doses can be estimated for 22 target organs of persons in four age groups and for selected organs of the fetus. Ingestion doses are calculated by combining age-group dose factors and intakes specific for age group, test event, and location as calculated by the PATHWAY food-chain model. Inhalation doses are calculated by combining age-group dose factors and breathing rates, and time-integrated air concentrations that are derived from the ORERP Air-Quality Data Base. Dose estimates are calculated for the radionuclides that contribute significantly to the total dose; these number 20 via the ingestion pathway and 46 via the inhalation pathway. Internal doses to nonspecified individuals and nonspecified fetuses are being reconstructed for each location in the ORERP Town Data Base for which exposure rates and cloud-arrival times are listed. Examples of reconstructing internal dose are presented. This method will also be adapted to reconstruct internal doses from NTS fallout to specific individuals in accordance with the person's age, past residence, life-style, and living pattern. PMID:2211124

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

    SciTech Connect

    Ng, Y.C.; Anspaugh, L.R.; Cederwall, R.T. )

    1990-11-01

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

  4. The use of radiation surveys to estimate the radiation effective dose to visitors of hospitalized patients--a theoretical study.

    PubMed

    Sherbini, Sami S; DeCicco, Joseph E

    2005-09-01

    Members of the public visiting hospitalized patients undergoing nuclear medicine procedures or brachytherapy are exposed to radiation emanating from the patient. The radiation protection staff at the hospital is responsible for ensuring that the doses to these visitors are kept as low as is reasonably achievable and are maintained below applicable regulatory limits. These limits are normally expressed in terms of the effective dose to the visitor. Direct measurement of the effective dose, however, is not feasible, and the use of a quantity that provides a reasonable estimate, referred to as a surrogate, is required. This study used Monte Carlo radiation transport calculations to examine the feasibility of using bedside survey results, in units of roentgens per hour, as a surrogate for estimating the effective dose to a person who may be present at the survey location. The Monte Carlo code used in this work was MCNP Version 5. In these calculations, both the patient and the visitor were modeled using modified Medical Internal Radiation Dose anthropomorphic phantoms. Radioactive material that emitted monoenergetic photons was located in several of the patient's organs in turn, and the bedside exposure rates and the effective doses at the same location were calculated. The calculations were repeated for several visitor locations, both at bedside along the length of the bed, and at increasing distances from the bed. The ratios of the exposure rates to the effective dose rates at each location gave an indication of the utility of the exposure rate measurements in providing a reasonable estimate of the effective dose. The results indicated that the survey data provided estimates of the effective dose within recommended accuracy for many exposure situations, but underestimated the effective dose to the visitor for other situations, especially locations close to bedside and for lower energy radiations. Use of appropriate correction factors based on this work could improve

  5. 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.

  6. 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. PMID:11686646

  7. 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.

  8. Amorphous and crystalline optical materials used as instruments for high gamma radiation doses estimations

    NASA Astrophysics Data System (ADS)

    Ioan, M.-R.

    2016-06-01

    Nuclear radiation induce some changes to the structure of exposed materials. The main effect of ionizing radiation when interacting with optical materials is the occurrence of color centers, which are quantitatively proportional to the up-taken doses. In this paper, a relation between browning effect magnitude and dose values was found. Using this relation, the estimation of a gamma radiation dose can be done. By using two types of laser wavelengths (532 nm and 633 nm), the optical powers transmitted thru glass samples irradiated to different doses between 0 and 59.1 kGy, were measured and the associated optical browning densities were determined. The use of laser light gives the opportunity of using its particularities: monochromaticity, directionality and coherence. Polarized light was also used for enhancing measurements quality. These preliminary results bring the opportunity of using glasses as detectors for the estimation of the dose in a certain point in space and for certain energy, especially in particles accelerators experiments, where the occurred nuclear reactions are involving the presence of high gamma rays fields.

  9. 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. PMID:24084521

  10. The chornobyl accident: estimation of radiation doses received by the Baltic and Ukrainian cleanup workers.

    PubMed

    Bouville, André; Chumak, Vadim V; Inskip, Peter D; Kryuchkov, Viktor; Luckyanov, Nickolas

    2006-07-01

    During the first day after the explosion, the Chornobyl accident of April 26, 1986 exposed a few hundred emergency workers to high dose levels ranging up to 16 Gy, resulting in acute radiation syndrome. Subsequently, several hundred thousand cleanup workers were sent to the Chornobyl power plant to mitigate the consequences of the accident. Depending on the nature of the work to be carried out, the cleanup workers were sent for periods ranging from several minutes to several months. The average dose from external radiation exposure that was received by the cleanup workers was about 170 mGy in 1986 and decreased from year to year. The radiation exposure was mainly due to external irradiation from gamma-ray-emitting radionuclides and was relatively homogeneous over all organs and tissues of the body. To assess the possible health consequences of external irradiation at relatively low dose rates, the U.S. National Cancer Institute is involved in two studies of Chornobyl cleanup workers: (1) a study of cancer incidence and thyroid disease among Estonian, Latvian and Lithuanian workers, and (2) a study of leukemia and other related blood diseases among Ukrainian workers. After an overview of the sources of exposure and of the radiation doses received by the cleanup workers, a description of the efforts made to estimate individual doses in the Baltic and Ukrainian studies is presented. PMID:16808604

  11. 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

  12. 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.

  13. 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.

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

    PubMed

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

    2016-04-01

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

  15. 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. PMID:26770031

  16. 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

  17. 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.

  18. Radiation exposure and dose estimates for a nuclear-powered manned Mars SPRINT mission

    NASA Astrophysics Data System (ADS)

    Nealy, John E.; Simonsen, Lisa C.; Wilson, John W.; Townsend, Lawrence W.; Qualls, Garry D.; Schnitzler, Bruce G.; 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 flare environment, while standard models are used for the trapped particle and galactic cosmic ray contributions. Shield effectiveness for several candidate materials are investigated.

  19. 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.

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

    NASA Astrophysics Data System (ADS)

    McMillan, Kyle Lorin

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

  1. 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.

  2. [Study on radiation dose estimation and monitor in TBI using an anthropomorphic phantom].

    PubMed

    Zhou, Y B; Yang, Y

    2001-11-01

    Absorbed doses and the dose distributions at important tissues and organs in an anthropomorphic phantom are measured using TLD under the TBI conditions. The dose for each tissue or organ is also estimated and monitored for TBI treatment. PMID:12583267

  3. 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

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

    PubMed

    Sheppard, S C; Sheppard, M I

    1988-06-01

    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

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. [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. PMID:26292419

  10. Estimation of collective effective dose due to natural background radiation in Egypt

    NASA Astrophysics Data System (ADS)

    Henaish, B. A.; Tawfik, A. A.; Abu Zaid, H.; Gomaa, M. A.

    1994-07-01

    During the last few years, worldwide attention has been directed towards the estimation of natural background radiation levels. Several environmental monitoring networks have been established for systematic data collection and exchange of information.In the present study, measurements of annual effective dose from terrestrial γ-rays are carried out at pre-selected sites within several Egyptian governorates by using a calibrated gas-filled GM-detector connected to a microcomputer system. Contribution of the secondary cosmic-rays, which is of prime importance at sea level, is achieved by carrying out computation based on theoretical considerations.Terrestrial effective dose in Egypt is found to be between 106 and 371 μSv/yr, meanwhile the computed cosmic rays contribution is 260-296 μSv/yr. Accordingly, the annual collective effective dose due to natural background radiation is about 27,253 Man Sv for the last Egyptian population count (1989) considering 0.8 and 0.2 indoor and outdoor occupancy factors.

  11. 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.

  12. Estimation of internal radiation dose from both immediate releases and continued exposures to contaminated materials.

    PubMed

    Napier, Bruce

    2012-03-01

    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, are discussed on the basis of 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 damaged reactors and also to the management of wastes that may be generated in both regional cleanup and decommissioning of the Fukushima nuclear power plant. PMID:22395282

  13. Radiation carcinogenesis in man: influence of dose-response models and risk projection models in the estimation of risk coefficients following exposure to low-level radiation

    SciTech Connect

    Fabrikant, J.I.

    1982-02-01

    The somatic effects of concern in human populations exposed to low doses and low dose rates of ionizing radiations are those that may be induced by mutation in individual cells, singly or in small numbers. The most important of these is considered to be cancer induction. Current knowledge of the carcinogenic effect of radiation in man has been reviewed in two recent reports: the 1977 UNSCEAR Report; and the 1980 BEIR-III Report. Both reports emphasize that cancers of the breast, thyroid, hematopoietic tissues, lung, and bone can be induced by radiation. Other cancers, including the stomach, pancreas, pharynx, lymphatic, and perhaps all tissues of the body, may also be induced by radiation. Both reports calculate risk estimates in absolute and relative terms for low-dose, low-LET whole-body exposure, and for leukemia, breast cancer, thyroid cancer, lung cancer, and other cancers. These estimates derive from exposure and cancer incidence data at high doses and at high dose rates. There are no compelling scientific reasons to apply these values of risk to the very low doses and low dose rates of concern in human radiation protection. In the absence of reliable human data for calculating risk estimates, dose-response models have been constructed from extrapolations of animal data and high-dose-rate human data for projection of estimated risks at low doses and low dose rates. (ERB)

  14. 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

  15. 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.

  16. 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

  17. 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

  18. Assessment of retrospective dose estimation, with fluorescence in situ hybridization (FISH), of six victims previously exposed to accidental ionizing radiation.

    PubMed

    Liu, Qing-Jie; Lu, Xue; Zhao, Xiao-Tao; Feng, Jiang-Bin; Lü, Yu-Min; Jiang, En-Hai; Zhang, Shu-Lan; Chen, De-Qing; Jia, Ting-Zhen; Liang, Li

    2014-01-01

    The present study aims to evaluate the use of the fluorescence in situ hybridization (FISH) translocation assay for retrospective dose estimation of acute accidental exposure to radiation in the past. Reciprocal translocation analysis by FISH with three whole-chromosome probes was performed on normal peripheral blood samples. Samples were irradiated with 0-5Gy (60)Co γ-rays in vitro, and dose-effect curves were established. FISH-based translocation analyses for six accident victims were then performed, and biological doses were estimated retrospectively by comparison with the dose-effect curves. Reconstructed doses by FISH were compared with estimated doses obtained by analysis of di-centrics performed soon after exposure, or with dose estimates from tooth-enamel electron paramagnetic resonance (EPR) data obtained at the same time as the FISH analysis. Follow-up FISH analyses for an adolescent victim were performed. Results showed that dose-effect curves established in the present study follow a linear-quadratic model, regardless of the background translocation frequency. Estimated doses according to two dose-effect curves for all six victims were similar. FISH dose estimations of three adult victims exposed to accidental radiation less than a decade prior to analysis (3, 6, or 7 years ago) were consistent with those estimated with tooth-enamel EPR measurements or analyses of di-centrics. Estimated doses of two other adult victims exposed to radiation over a decade prior to analysis (16 or 33 years ago) were underestimated and two to three times lower than the values obtained from analysis of di-centrics or tooth-enamel EPR. Follow-up analyses of the adolescent victim showed that doses estimated by FISH analysis decrease rapidly over time. Therefore, the accuracy of dose estimates by FISH is acceptable only when analysis is performed less than 7 years after exposure. Measurements carried out more than a decade after exposure through FISH analysis resulted in

  19. 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.

  20. 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.

  1. Average fetal depth in utero: data for estimation of fetal absorbed radiation dose

    SciTech Connect

    Ragozzino, M.W.; Breckle, R.; Hill, L.M.; Gray, J.E.

    1986-02-01

    To estimate fetal absorbed dose from radiographic examinations, the depth from the anterior maternal surface to the midline of the fetal skull and abdomen was measured by ultrasound in 97 pregnant women. The relationships between fetal depth, fetal presentation, and maternal parameters of height, weight, anteroposterior (AP) thickness, gestational age, placental location, and bladder volume were analyzed. Maternal AP thickness (MAP) can be estimated from gestational age, maternal height, and maternal weight. Fetal midskull and abdominal depths were nearly equal. Fetal depth normalized to MAP was independent or nearly independent of maternal parameters and fetal presentation. These data enable a reasonable estimation of absorbed dose to fetal brain, abdomen, and whole body.

  2. 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

  3. 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. PMID:20362943

  4. Patient-specific radiation dose and cancer risk estimation in pediatric chest CT: a study in 30 patients

    NASA Astrophysics Data System (ADS)

    Li, Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Frush, Donald P.

    2010-04-01

    Radiation-dose awareness and optimization in CT can greatly benefit from a dosereporting system that provides radiation dose and cancer risk estimates specific to each patient and each CT examination. Recently, we reported a method for estimating patientspecific dose from pediatric chest CT. The purpose of this study is to extend that effort to patient-specific risk estimation and to a population of pediatric CT patients. Our study included thirty pediatric CT patients (16 males and 14 females; 0-16 years old), for whom full-body computer models were recently created based on the patients' clinical CT data. Using a validated Monte Carlo program, organ dose received by the thirty patients from a chest scan protocol (LightSpeed VCT, 120 kVp, 1.375 pitch, 40-mm collimation, pediatric body scan field-of-view) was simulated and used to estimate patient-specific effective dose. Risks of cancer incidence were calculated for radiosensitive organs using gender-, age-, and tissue-specific risk coefficients and were used to derive patientspecific effective risk. The thirty patients had normalized effective dose of 3.7-10.4 mSv/100 mAs and normalized effective risk of 0.5-5.8 cases/1000 exposed persons/100 mAs. Normalized lung dose and risk of lung cancer correlated strongly with average chest diameter (correlation coefficient: r = -0.98 to -0.99). Normalized effective risk also correlated strongly with average chest diameter (r = -0.97 to -0.98). These strong correlations can be used to estimate patient-specific dose and risk prior to or after an imaging study to potentially guide healthcare providers in justifying CT examinations and to guide individualized protocol design and optimization.

  5. 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.

  6. 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.

  7. 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. PMID:17951606

  8. 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.

  9. 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.

  10. [Estimation of absorbed dose of beta radiation into the critical tissues by a single injection of tritiated water].

    PubMed

    Tsuchiya, T; Norimura, T; Yamamoto, H; Hatakeyama, S; Dohi, S; Kunugita, N

    1988-12-01

    The biological effects of tritium in humans need to be clarified, because the chances of humans becoming exposed to tritium beta radiation may increase with the development of the nuclear fusion reactor. To evaluate the biological effects of tritium, it is necessary to estimate exactly the absorbed dose from the tritium beta rays in the tissue. In many reports, the absorbed dose of HTO in the tissues is estimated from the tritium content in body fluid and dose calculations are customarily based upon the water content of soft tissues, which is taken to be 0.7 to 0.8. However, these methods may not show the exact absorbed dose in the organs. In the present study, the radioactivity of the critical tissues was measured directly using a sample oxidizer and the absorbed dose was calculated from the radioactivity of tritium in the tissues. Details on the method for calculation of the absorbed dose in tissues of the mouse is shown in this report. The results suggest that the absorbed dose should be obtained from the radioactivity in the tissues. PMID:3212298

  11. 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. PMID:2339701

  12. 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.

  13. 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

  14. The MIRD method of estimating absorbed dose

    SciTech Connect

    Weber, D.A.

    1991-01-01

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

  15. 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

  16. On the estimation of radiation-induced cancer risks from very low doses of radiation and how to communicate these risks.

    PubMed

    Mattsson, Sören; Nilsson, Mats

    2015-07-01

    The article is intended to give a short overview of epidemiological data on cancer risks associated with very low absorbed doses of ionising radiation. The linear no-threshold (LNT) approach to estimate cancer risks involves the use of epidemiological data at higher doses (>100 mSv), but is supported by data from lower exposure of more sensitive population groups like fetuses and children and the presence of rare types of cancer. The International Commission on Radiological Protection (ICRP) concludes that the LNT model, combined with a dose and dose-rate effectiveness (reduction) factor (DDREF) of 2 for extrapolation from high doses, should be used. The numerical value of the DDREF is challenged by the findings from some recent epidemiological studies demonstrating risks per unit dose compatible with the risks observed in the higher dose studies. In general there is very limited knowledge about the cancer risk after low absorbed doses (10-100 mSv), as most of epidemiological studies have limitations in detecting small excess risks arising from low doses of radiation against fluctuations in the influence of background risk factors. Even if there may be significant deviations from linearity in the relevant dose range 0-100 mSv, one does not know the magnitude or even the direction of any such deviations. The risks could be lower than those predicted by a linear extrapolation, but they could also be higher. Until more results concerning the effects of low-dose exposure are available, a reasonable radiation protection approach is to consider the risk proportional to the dose. PMID:25802468

  17. 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.

  18. Radiation dose estimation of sand samples collected from different Egyptian beaches.

    PubMed

    Eissa, H S; Medhat, M E; Said, S A; Elmaghraby, E K

    2011-11-01

    A high pure germanium detector-based gamma-ray spectroscopy low-background counting system was used to determine the levels of natural radioactivity from beach sand samples on the Egyptian coast along the Mediterranean and Red Seas. The activity concentrations of (226)Ra, (232)Th and (40)K were found to lie in the range of 30±11 to 60±14 Bq kg(-1) with a mean of 39±15 Bq kg(-1), 12±3 to 30±14 Bq kg(-1) with a mean of 21±13 Bq kg(-1) and 392±22 to 413±22 Bq kg(-1) with a mean of 402±23 Bq kg(-1), respectively. Radiation hazard indices and annual effective doses were evaluated and compared with the international data. The results indicate that the values obtained fall below the internationally accepted maximum limits and do not pose any significant radiation hazard to individuals in the study area. From these results, a radiological baseline map of Egyptian beaches can be drawn and used as reference information to assess any future alterations in the radioactivity of beach sands due to any changes in the sea sediments. PMID:21169289

  19. 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.

  20. 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).

  1. 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.

  2. High-Pitch Computed Tomography Coronary Angiography—A New Dose-Saving Algorithm: Estimation of Radiation Exposure

    PubMed Central

    Ketelsen, Dominik; Buchgeister, Markus; Korn, Andreas; Fenchel, Michael; Schmidt, Bernhard; Flohr, Thomas G.; Thomas, Christoph; Schabel, Christoph; Tsiflikas, Ilias; Syha, Roland; Claussen, Claus D.; Heuschmid, Martin

    2012-01-01

    Purpose. To estimate effective dose and organ equivalent doses of prospective ECG-triggered high-pitch CTCA. Materials and Methods. 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 second-generation dual-source scanner (SOMATOM Definition Flash, Siemens Medical Solutions, Germany). The following scan parameters were used: 320 mAs per rotation, 100 and 120 kV, pitch 3.4 for prospectively ECG-triggered high-pitch CTCA, scan range of 13.5 cm, collimation 64 × 2 × 0.6 mm with z-flying focal spot, gantry rotation time 280 ms, and simulated heart rate of 60 beats per minute. Results. Depending on the applied tube potential, the effective whole-body dose of the cardiac scan ranged from 1.1 mSv to 1.6 mSv and from 1.2 to 1.8 mSv for males and females, respectively. The radiosensitive breast tissue in the range of the primary beam caused an increased female-specific effective dose of 8.6%±0.3% compared to males. Decreasing the tube potential, a significant reduction of the effective dose of 35.8% and 36.0% can be achieved for males and females, respectively (P < 0.001). Conclusion. The radiologist and the CT technician should be aware of this new dose-saving strategy to keep the radiation exposure as low as reasonablly achievable. PMID:22701793

  3. 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.

  4. 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.

  5. Estimates of radiation dose and health risks to the United States population following the Chernobyl nuclear plant accident

    SciTech Connect

    Broadway, J.A.; Smith, J.M.; Norwood, D.L.; Porter, C.R.

    1988-09-01

    Estimates of both individual and collective doses received by the United States population following the Chernobyl accident have been made by using the data obtained from the U.S. Environmental Protection Agency's Environmental Radiation Ambient Monitoring System. Radionuclides associated with the debris first were measured in precipitation and surface air particulates at Portland, OR and Olympia, WA on 5 May 1986. Iodine-131 was the most consistently measured nuclide in all media, although several Cs and Ru isotopes also were observed. Strontium and any actinides notably were absent from the samples at the lower level of detection. The highest calculated individual-organ dose due to intake during May and June 1986 was 0.52 mSv to the infant thyroid in the state of Washington. This was predominantly (98%) from the ingestion of milk. The maximum U.S. collective dose equivalent to any organ was calculated to be 3,300 person-Sv to the thyroid. Risk estimates project three excess lung cancer deaths and an additional four deaths due to cancers of thyroid, breast and leukemia in the U.S. population over the next 45 y from exposure during the May-June 1986 interval. The only long-lived radionuclide measured in milk samples following the accident was 137Cs. We estimate 20 excess fatalities from the ingestion of 137Cs in milk during all subsequent years, with six of these due to lung cancer and the majority of the remainder distributed approximately equally among cancers of the thyroid, breast, liver and leukemia. A total of 100 excess fatalities from all dietary components was estimated. Because of the uncertainty of risk estimates from data such as those available for this study, all calculated values carry a range of uncertainty from a minimum of one-half the calculated value to a maximum of two times the calculated value.

  6. 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.

  7. Recommendations to the Technical Steering Panel regarding approach for estimating individual radiation doses resulting from releases of radionuclides to the Columbia River. Volume 1, Recommendations

    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.

  8. 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

  9. Evaluation of environmental contamination and estimated radiation doses for the return to residents' homes in Kawauchi Village, Fukushima prefecture.

    PubMed

    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 (134)Cs and (137)Cs. 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

  10. 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

  11. 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.

  12. Estimation of radiation risk in presence of classical additive and Berkson multiplicative errors in exposure doses.

    PubMed

    Masiuk, S V; Shklyar, S V; Kukush, A G; Carroll, R J; Kovgan, L N; Likhtarov, I A

    2016-07-01

    In this paper, the influence of measurement errors in exposure doses in a regression model with binary response is studied. Recently, it has been recognized that uncertainty in exposure dose is characterized by errors of two types: classical additive errors and Berkson multiplicative errors. The combination of classical additive and Berkson multiplicative errors has not been considered in the literature previously. In a simulation study based on data from radio-epidemiological research of thyroid cancer in Ukraine caused by the Chornobyl accident, it is shown that ignoring measurement errors in doses leads to overestimation of background prevalence and underestimation of excess relative risk. In the work, several methods to reduce these biases are proposed. They are new regression calibration, an additive version of efficient SIMEX, and novel corrected score methods. PMID:26795191

  13. 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.

  14. 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. PMID:18513985

  15. 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.

  16. 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. PMID:15381318

  17. Radiation dose estimation and mass attenuation coefficients of cement samples used in Turkey.

    PubMed

    Damla, N; Cevik, U; Kobya, A I; Celik, A; Celik, N; Van Grieken, R

    2010-04-15

    Different cement samples commonly used in building construction in Turkey have been analyzed for natural radioactivity using gamma-ray spectrometry. The mean activity concentrations observed in the cement samples were 52, 40 and 324 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. The measured activity concentrations for these radionuclides were compared with the reported data of other countries and world average limits. The radiological hazard parameters such as radium equivalent activities (Ra(eq)), gamma index (I(gamma)) and alpha index (I(alpha)) indices as well as terrestrial absorbed dose and annual effective dose rate were calculated and compared with the international data. The Ra(eq) values of cement are lower than the limit of 370 Bq kg(-1), equivalent to a gamma dose of 1.5 mSv y(-1). Moreover, the mass attenuation coefficients were determined experimentally and calculated theoretically using XCOM in some cement samples. Also, chemical compositions analyses of the cement samples were investigated. PMID:20018450

  18. Study of natural radioactivity and estimation of radiation dose in the environment of Tumkur, Karnataka, India.

    PubMed

    Jayasheelan, A; Manjunatha, S; Yashodhara, I; Karunakara, N

    2014-01-01

    The activity concentration of (226)Ra, (232)Th and (40)K was measured for soil samples collected from 34 locations of Tumkur District, Karnataka, India, using HPGe detector. The activity concentration of (226)Ra, (232)Th and (40)K varied from 9.6 to 71.6, 12.3 to 333.3 and 194.3 to 1527.7 Bq kg(-1) with an average value of 33.15, 123.01 and 877.76 Bq kg(-1), respectively. The absorbed and annual effective outdoor doses were found to be highest at Ponnasamudra with 258.98 nGy h(-1) and 317.62 μSv and lowest at Sira with 36.42 nGy h(-1) and 44.67 μSv, respectively. The external hazard index ranged from 0.21 to 1.58 with an average of 0.75. It was significant in 11 locations as it exceeded unity. PMID:23907323

  19. 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.

  20. 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.

  1. 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. PMID:27034103

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

    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: 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

  3. 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. PMID:26048012

  4. 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

  5. [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. PMID:23457971

  6. 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.

  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. 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.

  9. Estimation of patient radiation dose from whole body 18F- FDG PET/CT examination in cancer imaging: a preliminary study

    NASA Astrophysics Data System (ADS)

    Mahmud, M. H.; Nordin, A. J.; Saad, F. F. Ahmad; Fattah Azman, A. Z.

    2014-11-01

    This study aims to estimate the radiation effective dose resulting from whole body fluorine-18 flourodeoxyglucose Positron Emission Tomography (18F-FDG PET) scanning as compared to conservative Computed Tomography (CT) techniques in evaluating oncology patients. We reviewed 19 oncology patients who underwent 18F-FDG PET/CT at our centre for cancer staging. Internal and external doses were estimated using radioactivity of injected FDG and volume CT Dose Index (CTDIvol), respectively with employment of the published and modified dose coefficients. The median differences of dose among the conservative CT and PET protocols were determined using Kruskal Wallis test with p < 0.05 considered as significant. The median (interquartile range, IQR) effective doses of non-contrasted CT, contrasted CT and PET scanning protocols were 7.50 (9.35) mSv, 9.76 (3.67) mSv and 6.30 (1.20) mSv, respectively, resulting in the total dose of 21.46 (8.58) mSv. Statistically significant difference was observed in the median effective dose between the three protocols (p < 0.01). The effective doses of whole body 18F-FDG PET technique may be effective the lowest amongst the conventional CT imaging techniques.

  10. Ultraviolet radiation cataract: dose dependence

    NASA Astrophysics Data System (ADS)

    Soderberg, Per G.; Loefgren, Stefan

    1994-07-01

    Current safety limits for cataract development after acute exposure to ultraviolet radiation (UVR) are based on experiments analyzing experimental data with a quantal, effect-no effect, dose-response model. The present study showed that intensity of forward light scattering is better described with a continuous dose-response model. It was found that 3, 30 and 300 kJ/m2UVR300nm induces increased light scattering within 6 h. For all three doses the intensity of forward light scattering was constant after 6 h. The intensity of forward light scattering was proportional to the log dose of UVR300nm. There was a slight increase of the intensity of forward light scattering on the contralateral side in animals that received 300 kJ/m2. Altogether 72 Sprague-Dawley male rats were included. Half of the rats were exposed in vivo on one side to UVR300nm. The other half was kept as a control group, receiving the same treatment as exposed rats but without delivery of UVR300nm to the eye. Subgroups of the rats received either of the three doses. Rats were sacrificed at varying intervals after the exposure. The lenses were extracted and the forward light scattering was estimated. It is concluded that intensity of forward light scattering in the lens after exposure to UVR300nm should be described with a continuous dose-reponse model.

  11. 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.

  12. 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.

  13. 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

  14. Estimate Radiological Dose for Animals

    Energy Science and Technology Software Center (ESTSC)

    1997-12-18

    Estimate Radiological dose for animals in ecological environment using open literature values for parameters such as body weight, plant and soil ingestion rate, rad. halflife, absorbed energy, biological halflife, gamma energy per decay, soil-to-plant transfer factor, ...etc

  15. 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. PMID:26769857

  16. 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

  17. 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.

  18. Radiations in space: risk estimates.

    PubMed

    Fry, R J M

    2002-01-01

    The complexity of radiation environments in space makes estimation of risks more difficult than for the protection of terrestrial populations. In deep space the duration of the mission, position in the solar cycle, number and size of solar particle events (SPE) and the spacecraft shielding are the major determinants of risk. In low-earth orbit missions there are the added factors of altitude and orbital inclination. Different radiation qualities such as protons and heavy ions and secondary radiations inside the spacecraft such as neutrons of various energies, have to be considered. Radiation dose rates in space are low except for short periods during very large SPEs. Risk estimation for space activities is based on the human experience of exposure to gamma rays and to a lesser extent X rays. The doses of protons, heavy ions and neutrons are adjusted to take into account the relative biological effectiveness (RBE) of the different radiation types and thus derive equivalent doses. RBE values and factors to adjust for the effect of dose rate have to be obtained from experimental data. The influence of age and gender on the cancer risk is estimated from the data from atomic bomb survivors. Because of the large number of variables the uncertainities in the probability of the effects are large. Information needed to improve the risk estimates includes: (1) risk of cancer induction by protons, heavy ions and neutrons: (2) influence of dose rate and protraction, particularly on potential tissue effects such as reduced fertility and cataracts: and (3) possible effects of heavy ions on the central nervous system. Risk cannot be eliminated and thus there must be a consensus on what level of risk is acceptable. PMID:12382925

  19. Determining radiation dose to residents of radiation-contaminated buildings

    SciTech Connect

    Lee, J.J.S.; Wu, T.H.; Chong, N.S.; Dong, S.L.

    1999-08-01

    There are more than one thousand residents who lived in about 140 radiation-contaminated buildings and received the assessed radiation dose equivalent over 5 mSv/year. In this paper, a systematic approach to dose reconstruction is proposed for evaluating radiation dose equivalent to the residents. The approach includes area survey and exposure measurement, source identification and energy spectrum analysis, special designed TLD-embedded badges for residents to wear and organ dose estimation with Rando phantom simulation. From the study, it is concluded that the ionization chamber should still be considered as the primary modality for external dose measurement. However, lacking of accurate daily activity patterns of the residents, the dose equivalent estimation with the chamber measurements would be somehow overestimated. The encountered limitation could be compensated with the use of the TLD badges and Rando phantom simulation that could also provide more information for internal organ dose equivalent estimations. As the radiation patterns in the buildings are highly anisotropic, which strongly depends on the differences of structural and indoor layouts, it demands a mathematical model dealing with the above concerns. Also, further collaborations with studies on biological markers of the residents would make the entire dose equivalent estimation more helpful and reliable.

  20. A novel parameter, cell-cycle progression index, for radiation dose absorbed estimation in the premature chromosome condensation assay.

    PubMed

    Miura, Tomisato; Nakata, Akifumi; Kasai, Kosuke; Nakano, Manabu; Abe, Yu; Tsushima, Eiki; Ossetrova, Natalia I; Yoshida, Mitsuaki A; Blakely, William F

    2014-06-01

    The calyculin A-induced premature chromosome condensation (PCC) assay is a simple and useful method for assessing the cell-cycle distribution in cells, since calyculin A induces chromosome condensation in various phases of the cell cycle. In this study, a novel parameter, the cell-cycle progression index (CPI), in the PCC assay was validated as a novel biomarker for biodosimetry. Peripheral blood was drawn from healthy donors after informed consent was obtained. CPI was investigated using a human peripheral blood lymphocyte (PBL) ex vivo irradiation ((60)Co-gamma rays: ∼0.6 Gy min(-1), or X ray: 1.0 Gy min(-1); 0-10 Gy) model. The calyculin A-induced PCC assay was performed for chromosome preparation. PCC cells were divided into the following five categories according to cell-cycle stage: non-PCC, G1-PCC, S-PCC, G2/M-PCC and M/A-PCC cells. CPI was calculated as the ratio of G2/M-PCC cells to G1-PCC cells. The PCC-stage distribution varied markedly with irradiation doses. The G1-PCC cell fraction was significantly reduced, and the G2/M-PCC cell fraction increased, in 10-Gy-irradiated PBL after 48 h of culture. CPI levels were fitted to an exponential dose-response curve with gamma-ray irradiation [y = 0.6729 + 0.3934 exp(0.5685D), r = 1.0000, p < 0.0001] and X-ray irradiation [y = -0.3743 + 0.9744 exp(0.3321D), r = 0.9999, p < 0.0001]. There were no significant individual (p = 0.853) or gender effects (p = 0.951) on the CPI in the human peripheral blood ex vivo irradiation model. Furthermore, CPI measurements are rapid (< 15 min per case). These results suggest that the CPI is a useful screening tool for the assessment of radiation doses received ranging from 0 to 10 Gy in radiation exposure early after a radiation event, especially after a mass-casualty radiological incident. PMID:24743756

  1. The estimation of the dose from cosmic radiation received by the population living at mainland of China

    NASA Astrophysics Data System (ADS)

    Jin, Hua; Yue, Qingyu

    1989-11-01

    The measurement of ionization distribution caused by the cosmic ray ionizing components in the air, the survey of population distribution in geography and the investigation of total passengers taking air liners at the mainland of China have been completed. By taking the data from the census of the year 1986 and the population distribution of the mainland, considering the cosmic ray distribution with the height and referring the distribution of neutron flux density in cosmic rays, the population-weighted mean annual effective dose equivalent, which is obtained from 2017 counties and 353 cities, for inhabitants living in every provinces and municipalities directly under Central Government has been calculated. The collective dose equivalent produced by the external exposure of cosmic rays is also estimated when people are taking air liners. The results which are effected by the population distribution show that the annual effective dose equivalant received by the population of China from cosmic rays is 28 lower lower than the population of the world. Most of Chinese people are living in the Northern Hemisphere area that has a lower elevation and geomagnetic latitude, and 53.6 percent of them are in the area of elevation below 100 m and 91 percent are in the area of geomagnetic latitude below 30 deg N.

  2. Variation in lunar neutron dose estimates.

    PubMed

    Slaba, Tony C; Blattnig, Steve R; Clowdsley, Martha S

    2011-12-01

    The radiation environment on the Moon includes albedo neutrons produced by primary particles interacting with the lunar surface. In this work, HZETRN2010 is used to calculate the albedo neutron contribution to effective dose as a function of shielding thickness for four different space radiation environments and to determine to what extent various factors affect such estimates. First, albedo neutron spectra computed with HZETRN2010 are compared to Monte Carlo results in various radiation environments. Next, the impact of lunar regolith composition on the albedo neutron spectrum is examined, and the variation on effective dose caused by neutron fluence-to-effective dose conversion coefficients is studied. A methodology for computing effective dose in detailed human phantoms using HZETRN2010 is also discussed and compared. Finally, the combined variation caused by environmental models, shielding materials, shielding thickness, regolith composition and conversion coefficients on the albedo neutron contribution to effective dose is determined. It is shown that a single percentage number for characterizing the albedo neutron contribution to effective dose can be misleading. In general, the albedo neutron contribution to effective dose is found to vary between 1-32%, with the environmental model, shielding material and shielding thickness being the driving factors that determine the exact contribution. It is also shown that polyethylene or other hydrogen-rich materials may be used to mitigate the albedo neutron exposure. PMID:21859325

  3. 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

  4. 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.

  5. 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…

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

    PubMed

    Kubota, Yoshihisa; Takahashi, Hiroyuki; Watanabe, Yoshito; Fuma, Shoichi; Kawaguchi, Isao; Aoki, Masanari; Kubota, Masahide; Furuhata, Yoshiaki; Shigemura, Yusaku; Yamada, Fumio; Ishikawa, Takahiro; Obara, Satoshi; Yoshida, Satoshi

    2015-04-01

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

  7. A Monte Carlo-based method to estimate radiation dose from spiral CT: from phantom testing to patient-specific models

    NASA Astrophysics Data System (ADS)

    Jarry, G.; DeMarco, J. J.; Beifuss, U.; Cagnon, C. H.; McNitt-Gray, M. F.

    2003-08-01

    The purpose of this work is to develop and test a method to estimate the relative and absolute absorbed radiation dose from axial and spiral CT scans using a Monte Carlo approach. Initial testing was done in phantoms and preliminary results were obtained from a standard mathematical anthropomorphic model (MIRD V) and voxelized patient data. To accomplish this we have modified a general purpose Monte Carlo transport code (MCNP4B) to simulate the CT x-ray source and movement, and then to calculate absorbed radiation dose in desired objects. The movement of the source in either axial or spiral modes was modelled explicitly while the CT system components were modelled using published information about x-ray spectra as well as information provided by the manufacturer. Simulations were performed for single axial scans using the head and body computed tomography dose index (CTDI) polymethylmethacrylate phantoms at both central and peripheral positions for all available beam energies and slice thicknesses. For comparison, corresponding physical measurements of CTDI in phantom were made with an ion chamber. To obtain absolute dose values, simulations and measurements were performed in air at the scanner isocentre for each beam energy. To extend the verification, the CT scanner model was applied to the MIRD V model and compared with published results using similar technical factors. After verification of the model, the generalized source was simulated and applied to voxelized models of patient anatomy. The simulated and measured absolute dose data in phantom agreed to within 2% for the head phantom and within 4% for the body phantom at 120 and 140 kVp; this extends to 8% for the head and 9% for the body phantom across all available beam energies and positions. For the head phantom, the simulated and measured absolute dose data agree to within 2% across all slice thicknesses at 120 kVp. Our results in the MIRD phantom agree within 11% of all the different organ dose values

  8. Estimates of doses from global fallout.

    PubMed

    Bouville, André; Simon, Steven L; Miller, Charles W; Beck, Harold L; Anspaugh, Lynn R; Bennett, Burton G

    2002-05-01

    This paper summarizes information about external and internal doses resulting from global fallout and presents preliminary estimates of doses resulting from intermediate fallout in the contiguous United States. Most of the data on global fallout were extracted from the reports of the United Nations Scientific Committee on the Effects of Atomic Radiation, in which the radiation exposures from fallout have been extensively reviewed at regular intervals. United Nations Scientific Committee on the Effects of Atomic Radiation estimated the average effective doses received by the world's population before 2000 to be about 0.4 mSv from external irradiation and 0.6 mSv from internal irradiation, the main radionuclide contributing to the effective dose being 137Cs. Effective doses received beyond 2000 result mainly from the environmentally mobile, long-lived 14C and amount to about 2.5 mSv summed over present and future generations. Specific information about the doses from fallout received by the United States population is based on the preliminary results of a study requested by the U.S. Congress and conducted jointly by the Centers for Disease Control and Prevention and the National Cancer Institute. Separate calculations were made for the tests conducted at the Nevada Test Site and for the high-yield tests conducted mainly by the United States and the former Soviet Union at sites far away from the contiguous United States (global tests). The estimated average doses from external irradiation received by the United States population were about 0.5 mGy for Nevada Test Site fallout and about 0.7 mGy for global fallout. These values vary little from one organ or tissue of the body to another. In contrast, the average doses from internal irradiation vary markedly from one organ or tissue to another; estimated average thyroid doses to children born in 1951 were about 30 mGy from Nevada Test Site fallout and about 2 mGy from global fallout. PMID:12003019

  9. Radiation dose rate meter

    SciTech Connect

    Kronenberg, S.; Siebentritt, C.R.

    1981-07-28

    A combined dose rate meter and charger unit therefor which does not require the use of batteries but on the other hand produces a charging potential by means of a piezoelectric cylinder which is struck by a manually triggered hammer mechanism. A tubular type electrometer is mounted in a portable housing which additionally includes a geiger-muller (Gm) counter tube and electronic circuitry coupled to the electrometer for providing multi-mode operation. In one mode of operation, an rc circuit of predetermined time constant is connected to a storage capacitor which serves as a timed power source for the gm tube, providing a measurement in terms of dose rate which is indicated by the electrometer. In another mode, the electrometer indicates individual counts.

  10. Radiation risk estimation models

    SciTech Connect

    Hoel, D.G.

    1987-11-01

    Cancer risk models and their relationship to ionizing radiation are discussed. There are many model assumptions and risk factors that have a large quantitative impact on the cancer risk estimates. Other health end points such as mental retardation may be an even more serious risk than cancer for those with in utero exposures. 8 references.

  11. 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

  12. 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.

  13. 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.

  14. 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. PMID:26011495

  15. External radiation exposure of residents living close to the Mayak facility: main sources, dose estimates, and comparison with earlier assessments.

    PubMed

    Mokrov, Yury G

    2004-07-01

    In 1951 and 1952 specialists from the Mayak production association investigated the radiological situation in the area of the Metlinski reservoir that was located 5-7 km from the site of liquid radioactive waste (LRW) discharge. Based on their measurements of both the specific radioactivity in the water and the dose-rate above the water surface, the gamma-field above the water surface in 1951 was demonstrated to be mainly due to (95)Zr+(95)Nb. The dose-rate at the shore of the reservoir was calculated for the period 1949-1951. In November and December 1951, the gamma-field at the shore was mainly due to (140)Ba+(140)La. For the period 1949-1951, the external exposure of the Metlino population due to the decay of these radionuclides was about 200 R (2 Sv), most of the dose having been produced in 1951. The contribution of (137)Cs to external doses did at that time probably not exceed a fraction of several percent. This finding is in contradiction to the assumptions made in the most recent TRDS-2000 system that was developed to reconstruct the doses to the residents of the Techa river. The results presented here demonstrate that the reconstruction of external doses received by the Metlino population as well as by the Techa river residents can be improved for the most critical period between 1949 and 1954. PMID:15221313

  16. 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

  17. ACRA-TRIT: The Tritium Version of ACRA-II, Estimation of Radiation Doses Caused by a Hypothetical Reactor Accident

    Energy Science and Technology Software Center (ESTSC)

    1981-12-01

    ACRA-TRIT is an atmospheric dispersion code which, using a three- (or two-) dimensional normal distribution model calculates the external dose, the internal dose due to inhalation, and the ground contamination that can be expected from the transport, fallout, and washout of the radioactive products released to the atmosphere in either a continuous fashion or an accidental short-term release. Allowance is made for elevated receptors above ground, for variable height of the plume centerline, and formore » reflection on the ground and on a possible inversion layer in the atmosphere.« less

  18. 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.

  19. [Evaluation of radiation doses in mammography].

    PubMed

    Lee, S K; Hwang, S K; Lee, L N; Lou, G C; Wang, C A; Hsu, W J

    1993-03-01

    A dedicated X-ray mammography was introduced to our hospital from 1987 and an imaging receptor of xeroradiography was applied. We reported previously that the average air exposure was 0.79R and that the absorption dose of skin was 1.00 rad. These data are similar to literature reports. Screen-film mammography was introduced recently. To select the best breast imaging and the least radiation exposure, diverse methods were investigated. A dosimetry (Capintec model 192) and a PS-033 parallel ionization chamber were applied to compare the absorption dose on polystyrene phantom between various exposure factors, the application of breast clamp and the size of exposure field. Retrospective estimation of the radiation dose was obtained from the exposure factors of previous mammography since July, 1990 to May, 1992. There were 1035 xeromammographic examinations and 358 examinations with medium-speed screen-film mammography. Another 61 craniocaudal and 96 mediolateral projections with high-speed screen-film mammography were recruited during the recent two months. An ionization chamber (Exradin, Shonka-Wyckoff A5) with an electrometer (Keithley 617) wer selected to obtain the dose equivalent from air exposure between selected exposure factors. The radiation dose of mammography is linearly correlated with voltage/kV and current/mAs. The application of a breast clump reduces 10% of the skin dose. The average exposure factors of xeromammography are 45.6 kV, 163.5 mAs. These results remain the same as in our previous report. Xeromammography has a greater exposure to air, estimated average glandular dose and absorbed dose than screen-film mammography. The mean exposure factor of rapid screen-film mammography gains half the value of medium screen-film mammography, ie. 26.6 kV, 87.0 mAs vs. 26.0 kV, 164.5 mAs.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8490794

  20. 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. PMID:2698842

  1. 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

  2. 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.

  3. 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. PMID:22828078

  4. 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

  5. Early dose assessment following severe radiation accidents

    SciTech Connect

    Goans, R.E.; Holloway, E.C.; Berger, M.E.; Ricks, R.C.

    1997-04-01

    Early treatment of victims of high level acute whole-body x-ray or gamma exposure has been shown to improve their likelihood of survival. However, in such cases, both the magnitude of the exposure and the dosimetry profile(s) of the victim(s) are often not known in detail for days to weeks. A simple dose-prediction algorithm based on lymphocyte kinetics as documented in prior radiation accidents is presented here. This algorithm provides an estimate of dose within the first 8 h following an acute whole-body exposure. Early lymphocyte depletion kinetics after a severe radiation accident follow a single exponential, L(t) = L{sub o}e{sup -k(D)t}, where k(D) is a rate constant, dependent primarily on the average dose, D. Within the first 8 h post-accident, K(D) may be calculated utilizing serial lymphocyte counts. Data from the REAC/TS Radiation Accident Registry were used to develop a dose-prediction algorithm from 43 gamma exposure cases where both lymphocyte kinetics and dose reconstruction were felt to be reasonably reliable. The inverse relationship D(K) may be molded by a simple two parameter curve of the form D = a/(1 + b/K) in the range 0 {le} D {le} 15 Gy, with fitting parameters (mean {+-} SD): a = 13.6 {+-} 1.7 Gy, and b = 1.0 {+-} 0.20 d{sup -1}. Dose estimated in this manner is intended to serve only as a first approximation to guide initial medical management. 31 refs., 4 figs., 2 tabs.

  6. Estimation of dose enhancement to soft tissue due to backscatter radiation near metal interfaces during head and neck radiothearpy - A phantom dosimetric study with radiochromic film

    PubMed Central

    Kinhikar, Rajesh Ashok; Tambe, Chandrashekhar M; Patil, Kalpana; Mandavkar, Mahadev; Deshpande, Deepak D; Gujjalanavar, Rajendra; Yadav, Prabha; Budrukkar, Ashwini

    2014-01-01

    The objective of this study was to investigate the dose enhancement to soft tissue due to backscatter radiation near metal interfaces during head and neck radiotherapy. The influence of titanium-mandibular plate with the screws on radiation dose was tested on four real bones from mandible with the metal and screws fixed. Radiochromic films were used for dosimetry. The bone and metal were inserted through the film at the center symmetrically. This was then placed in a small jig (7 cm × 7 cm × 10 cm) to hold the film vertically straight. The polymer granules (tissue-equivalent) were placed around the film for homogeneous scatter medium. The film was irradiated with 6 MV X-rays for 200 monitor units in Trilogy linear accelerator for 10 cm × 10 cm field size with source to axis distance of 100 cm at 5 cm. A single film was also irradiated without any bone and metal interface for reference data. The absolute dose and the vertical dose profile were measured from the film. There was 10% dose enhancement due to the backscatter radiation just adjacent to the metal-bone interface for all the materials. The extent of the backscatter effect was up to 4 mm. There is significant higher dose enhancement in the soft tissue/skin due to the backscatter radiation from the metallic components in the treatment region. PMID:24600171

  7. 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.

  8. 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. PMID:19820457

  9. 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.

  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. 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.

  12. [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. PMID:20803991

  13. 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.

  14. 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.

  15. 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. PMID:15880917

  16. 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})

  17. 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).

  18. 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.

  19. A Program for Calculating Radiation Dose Rates.

    Energy Science and Technology Software Center (ESTSC)

    1986-01-27

    Version 00 SMART calculates radiation dose rate at the center of the outer cask surface. It can be applied to determine the radiation dose rate on each cask if source conditions, characteristic function, and material conditions in the bottle regions are given. MANYCASK calculates radiation dose rate distribution in a space surrounded by many casks. If the dose rate on each cask surface can be measured, MANYCASK can be applied to predict dose spatial dosemore » rate distribution for any case of cask configuration.« less

  20. 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.

  1. Early dose assessment following severe radiation accidents

    SciTech Connect

    Goans, R.E.; Holloway, E.C.

    1996-06-01

    Prompt and aggressive treatment of victims to high level whole-body gamma exposure has been shown to improve their likelihood of survival. However, in such cases, both the magnitude of the accident and the dosimetry profile(s) of the victim(s) are often not known in detail for days to weeks. Medical intervention could therefore be delayed after a major accident because of uncertainties in the initial dose estimate. A simple dose-prediction algorithm based on lymphocyte kinetics as documented in prior radiation accidents is presented here. This algorithm provides an estimate of marrow dose within the first 12-18 h following an acute whole-body gamma exposure. Early lymphocyte depletion curves post-accident follow a single exponential, L(t) = L{sub o}e{sup -k(D)t}, where L{sub o} is the pre- accident lymphocyte count and k(D) is a rate constant, dependent on the average dose, D. Within the first 12-18 h post-accident, K(D) may be calculated utilizing serial lymphocyte counts. Data from the REAC/TS Accident Registry were used to develop a dose prediction algorithm from 43 gamma exposure cases where both lymphocyte kinetics and dose reconstruction were felt to be reasonably reliable. The relationship D(K) is shown to follow a logistic dose response curve of the form D = a/[1 + (K/b){sup c}] in the range 0 {le} D {le} 15 Gy. The fitting parameters (mean {+-} SD) are found to be a = 21.5 {+-} 5.8 Gy, b = 1.75 {+-} 0.99 d{sup -1}, and c = -0.98 {+-} 0.14, respectively. The coefficient of determination r{sup 2} for the fit is 0.90 with an F-value of 174.7. Dose estimated in this manner is intended to serve only as a first approximation to guide initial medical-management. The treatment regimen may then be modified as needed after more exact dosimetry has become available.

  2. 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).

  3. 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...

  4. 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. PMID:21449579

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Radiation doses in chest, abdomen and pelvis CT procedures.

    PubMed

    Manssor, E; Abuderman, A; Osman, S; Alenezi, S B; Almehemeid, S; Babikir, E; Alkhorayef, M; Sulieman, A

    2015-07-01

    Computed tomography (CT) scanning is recognised as a high-radiation dose modality and estimated to be 17 % of the radiological procedure and responsible for 70 % of medical radiation exposure. Although diagnostic X rays provide great benefits, their use involves some risk for developing cancer. The objectives of this study are to estimate radiation doses during chest, abdomen and pelvis CT. A total of 51 patients were examined for the evaluation of metastasis of a diagnosed primary tumour during 4 months. A calibrated CT machine from Siemens 64 slice was used. The mean age was 48.0 ± 18.6 y. The mean patient weight was 73.8 ± 16.1 kg. The mean dose-length product was 1493.8 ± 392.1 mGy cm, Volume CT dose index (CTDI vol) was 22.94 ± 5.64 mGy and the mean effective dose was 22.4 ± 5.9 mSv per procedure. The radiation dose per procedure was higher as compared with previous studies. Therefore, the optimisation of patient's radiation doses is required in order to reduce the radiation risk. PMID:25852181

  10. 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. PMID:26874225

  11. 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. PMID:26160852

  12. 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.

  13. Estimates of bias and uncertainty in recorded external dose

    SciTech Connect

    Fix, J.J.; Gilbert, E.S.; Baumgartner, W.V.

    1994-10-01

    A study is underway to develop an approach to quantify bias and uncertainty in recorded dose estimates for workers at the Hanford Site based on personnel dosimeter results. This paper focuses on selected experimental studies conducted to better define response characteristics of Hanford dosimeters. The study is more extensive than the experimental studies presented in this paper and includes detailed consideration and evaluation of other sources of bias and uncertainty. Hanford worker dose estimates are used in epidemiologic studies of nuclear workers. A major objective of these studies is to provide a direct assessment of the carcinogenic risk of exposure to ionizing radiation at low doses and dose rates. Considerations of bias and uncertainty in the recorded dose estimates are important in the conduct of this work. The method developed for use with Hanford workers can be considered an elaboration of the approach used to quantify bias and uncertainty in estimated doses for personnel exposed to radiation as a result of atmospheric testing of nuclear weapons between 1945 and 1962. This approach was first developed by a National Research Council (NRC) committee examining uncertainty in recorded film badge doses during atmospheric tests (NRC 1989). It involved quantifying both bias and uncertainty from three sources (i.e., laboratory, radiological, and environmental) and then combining them to obtain an overall assessment. Sources of uncertainty have been evaluated for each of three specific Hanford dosimetry systems (i.e., the Hanford two-element film dosimeter, 1944-1956; the Hanford multi-element film dosimeter, 1957-1971; and the Hanford multi-element TLD, 1972-1993) used to estimate personnel dose throughout the history of Hanford operations. Laboratory, radiological, and environmental sources of bias and uncertainty have been estimated based on historical documentation and, for angular response, on selected laboratory measurements.

  14. 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.

  15. 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.

  16. Patient Radiation Doses in Interventional Cardiology Procedures

    PubMed Central

    Pantos, Ioannis; Patatoukas, Georgios; Katritsis, Demosthenes G; Efstathopoulos, Efstathios

    2009-01-01

    Interventional cardiology procedures result in substantial patient radiation doses due to prolonged fluoroscopy time and radiographic exposure. The procedures that are most frequently performed are coronary angiography, percutaneous coronary interventions, diagnostic electrophysiology studies and radiofrequency catheter ablation. Patient radiation dose in these procedures can be assessed either by measurements on a series of patients in real clinical practice or measurements using patient-equivalent phantoms. In this article we review the derived doses at non-pediatric patients from 72 relevant studies published during the last 22 years in international scientific literature. Published results indicate that patient radiation doses vary widely among the different interventional cardiology procedures but also among equivalent studies. Discrepancies of the derived results are patient-, procedure-, physician-, and fluoroscopic equipmentrelated. Nevertheless, interventional cardiology procedures can subject patients to considerable radiation doses. Efforts to minimize patient exposure should always be undertaken. PMID:20066141

  17. 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.

  18. Dose assurance in radiation processing plants

    NASA Astrophysics Data System (ADS)

    Miller, A.; Chadwick, K. H.; Nam, J. W.

    Radiation processing relies to a large extent on dosimetry as control of proper operation. This applies in particular to radiation sterilization of medical products and food treatment, but also during development of any other process. The assurance that proper dosimetry is performed at the radiation processing plant can be obtained through the mediation of an international organization, and the IAEA is now implementing a dose assurance service for industrial radiation processing.

  19. 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. PMID:26776265

  20. 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.

  1. 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)

  2. Gamma Radiation Doses In Sweden

    NASA Astrophysics Data System (ADS)

    Almgren, Sara; Barregârd, Lars; Isaksson, Mats

    2008-08-01

    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)μSv/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)μSv/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, 222Rn measurements were performed in each dwelling, which showed no correlation with the gamma dose rates in the dwellings.

  3. 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.

  4. 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. PMID:22641644

  5. 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. PMID:17223639

  6. Doses from Medical Radiation Sources

    MedlinePlus

    ... radiation dosimetry. Continuing Medical Education Article, Journal of Nuclear Medicine 41(5):863–873; 2000. © 2016 Health Physics Society Site Map | Privacy Statement | Disclaimer | Webmaster

  7. 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...

  8. 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.

  9. 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.

  10. Generalized Spearman estimators of relative dose.

    PubMed

    Morton, R

    1981-06-01

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

  11. 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

  12. 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)

  13. 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.

  14. 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.

  15. Analytic estimates of secondary neutron dose in proton therapy

    NASA Astrophysics Data System (ADS)

    Anferov, V.

    2010-12-01

    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.

  16. Dose specification for radiation therapy: dose to water or dose to medium?

    PubMed

    Ma, C-M; Li, Jinsheng

    2011-05-21

    The Monte Carlo method enables accurate dose calculation for radiation therapy treatment planning and has been implemented in some commercial treatment planning systems. Unlike conventional dose calculation algorithms that provide patient dose information in terms of dose to water with variable electron density, the Monte Carlo method calculates the energy deposition in different media and expresses dose to a medium. This paper discusses the differences in dose calculated using water with different electron densities and that calculated for different biological media and the clinical issues on dose specification including dose prescription and plan evaluation using dose to water and dose to medium. We will demonstrate that conventional photon dose calculation algorithms compute doses similar to those simulated by Monte Carlo using water with different electron densities, which are close (<4% differences) to doses to media but significantly different (up to 11%) from doses to water converted from doses to media following American Association of Physicists in Medicine (AAPM) Task Group 105 recommendations. Our results suggest that for consistency with previous radiation therapy experience Monte Carlo photon algorithms report dose to medium for radiotherapy dose prescription, treatment plan evaluation and treatment outcome analysis. PMID:21508447

  17. 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.

  18. 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.

  19. Capture and analysis of radiation dose reports for radiology.

    PubMed

    Midgley, S M

    2014-12-01

    Radiographic imaging systems can produce records of exposure and dose parameters for each patient. A variety of file formats are in use including plain text, bit map images showing pictures of written text and radiation dose structured reports as text or extended markup language files. Whilst some of this information is available with image data on the hospital picture archive and communication system, access is restricted to individual patient records, thereby making it difficult to locate multiple records for the same scan protocol. This study considers the exposure records and dose reports from four modalities. Exposure records for mammography and general radiography are utilized for repeat analysis. Dose reports for fluoroscopy and computed tomography (CT) are utilized to study the distribution of patient doses for each protocol. Results for dosimetric quantities measured by General Radiography, Fluoroscopy and CT equipment are summarised and presented in the Appendix. Projection imaging uses the dose (in air) area product and derived quantities including the dose to the reference point as a measure of the air kerma reaching the skin, ignoring movement of the beam for fluoroscopy. CT uses the dose indices CTDIvol and dose length product as a measure of the dose per axial slice, and to the scanned volume. Suitable conversion factors are identified and used to estimate the effective dose to an average size patient (for CT and fluoroscopy) and the entrance skin dose for fluoroscopy. PMID:25315104

  20. Patient perspectives on radiation dose.

    PubMed

    Graff, Joyce

    2014-03-01

    People with genetic cancer syndromes have a special interest in imaging. They also have special risk factors with respect to radiation. They need to utilize the potential of imaging while keeping in mind concerns about cumulative radiation exposure. Before imaging, early detection of problems was limited. With imaging, issues can be identified when they are small and a good plan of action can be developed early. Operations can be planned and metastatic cancer avoided. The positive contribution of imaging to the care of these patients can be profound. However, this additional surveillance is not without cost. An average patient with 1 of these syndromes will undergo 100 or more scans in their lifetime. Imaging professionals should be able to describe the risks and benefits of each scan in terms that the patient and the ordering physician can understand to make smart decisions about the ordering of scans. Why CT versus MRI? When are x-ray or ultrasound appropriate, and when are they not? What are the costs and the medical risks for the patient? What value does this picture add for the physician? Is there a way to answer the medical question with a test other than a scan? Medicine is a team sport, and the patient is an integral member of the team. PMID:24589397

  1. 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.

  2. 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.

  3. 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.

  4. Imaging of Radiation Dose for Stereotactic Radiosurgery.

    PubMed

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

    2015-01-01

    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. PMID:27421869

  5. 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.’

  6. 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.

  7. Effect of radon measurement methods on dose estimation.

    PubMed

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

    2011-05-01

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

  8. 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

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2000-11-01

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

  15. 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.

  16. Reducing ionizing radiation doses during cardiac interventions in pregnant women

    PubMed Central

    Orchard, Elizabeth; Dix, Sarah; Wilson, Neil; Mackillop, Lucy; Ormerod, Oliver

    2012-01-01

    Background There is concern over ionizing radiation exposure in women who are pregnant or of child-bearing age. Due to the increasing prevalence of congenital and acquired heart disease, the number of women who require cardiac interventions during pregnancy has increased. We have developed protocols for cardiac interventions in pregnant women and women of child-bearing age, aimed at substantially reducing both fluoroscopy duration and radiation doses. Methods Over five years, we performed cardiac interventions on 15 pregnant women, nine postpartum women and four as part of prepregnancy assessment. Fluoroscopy times were minimized by simultaneous use of intracardiac echocardiography, and by using very low frame rates (2/second) during fluoroscopy. Results The procedures most commonly undertaken were closure of atrial septal defect (ASD) or patent foramen ovale (PFO) in 16 women, coronary angiograms in seven, right and left heart catheters in three and two stent placements. The mean screening time for all patients was 2.38 minutes (range 0.48–13.7), the median radiation dose was 66 (8.9–1501) Gy/cm2. The median radiation dose to uterus was 1.92 (0.59–5.47) μGy, and the patient estimated dose was 0.24 (0.095–0.80) mSv. Conclusions Ionizing radiation can be used safely in the management of severe cardiac structural disease in pregnancy, with very low ionizing radiation dose to the mother and extremely low exposure to the fetus. With experience, ionizing radiation doses at our institution have been reduced.

  17. 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.

  18. Assessment of radiation doses downwind of the Nevada Test Site

    SciTech Connect

    Anspaugh, L.R.; Church, B.W.

    1983-11-01

    The Department of Energy's Off-Site Radiation Exposure Review Project has the goal of reconstructing both individual and population doses via all pathways including the ingestion and inhalation of radionuclides. As this is a reconstruction and not a prediction for safety purposes, the desired output is the best estimate of radiation dose with an appropriate expression of uncertainty. For the 80 events of interest, the data consistently available are external ..gamma.. exposure-rate measurements, measurements of airborne gross ..beta.. activity, and measurements of fission yield and of activation products created in the device environment. For most organs, the external ..gamma.. dose is much greater than the dose from ingestion which, in turn, is much greater than the dose from inhalation. The gastrointestinal tract may receive as large a dose from ingestion as from external exposure, depending upon dietary habits. The dose to the thyroid gland is usually dominated by ingestion and the dose from inhalation can be nearly as large as that from external exposure. Several example calculations are presented for specific individuals.

  19. 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.

  20. Reduction of Radiation Doses to Patients and Staff During Endoscopic Retrograde Cholangiopancreatography

    PubMed Central

    Sulieman, Abdelmoneim; Paroutoglou, Georgios; Kapsoritakis, Andreas; Kapatenakis, Anargeyros; Potamianos, Spiros; Vlychou, Marianna; Theodorou, Kiki

    2011-01-01

    Background/Aim: Endoscopic retrograde cholangiopancreatography (ERCP) is associated with a considerable radiation exposure for patients and staff. While optimization of the radiation dose is recommended, few studies have been published. The purpose of this study has been to measure patient and staff radiation dose, to estimate the effective dose and radiation risk using digital fluoroscopic images. Entrance skin dose (ESD), organ and effective doses were estimated for patients and staff. Materials and Methods: Fifty-seven patients were studied using digital X-ray machine and thermoluminescent dosimeters (TLD) to measure ESD at different body sites. Organ and surface dose to specific radiosensitive organs was carried out. The mean, median, minimum, third quartile and the maximum values are presented due to the asymmetry in data distribution. Results: The mean ESD, exit and thyroid surface dose were estimated to be 75.6 mGy, 3.22 mGy and 0.80 mGy, respectively. The mean effective dose for both gastroenterologist and assistant is 0.01 mSv. The mean patient effective dose was 4.16 mSv, and the cancer risk per procedure was estimated to be 2 × 10-5 Conclusion: ERCP with fluoroscopic technique demonstrate improved dose reduction, compared to the conventional radiographic based technique, reducing the surface dose by a factor of 2, without compromising the diagnostic findings. The radiation absorbed doses to the different organs and effective doses are relatively low. PMID:21196649

  1. 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:...

  2. Estimating potential evapotranspiration with improved radiation estimation

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  3. 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.

  4. 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.

  5. Scientific issues in radiation dose reconstruction.

    PubMed

    Toohey, Richard E

    2008-07-01

    Stakeholders have raised numerous issues regarding the scientific basis of radiation dose reconstruction for compensation. These issues can be grouped into three broad categories: data issues, dosimetry issues, and compensation issues. Data issues include demographic data of the worker, changes in site operations over time (both production and exposure control), characterization of episodic vs. chronic exposures, and the use of coworker data. Dosimetry issues include methods for assessment of ambient exposures, missed dose, unmonitored dose, and medical x-ray dose incurred as a condition of employment. Specific issues related to external dose include the sensitivity, angular and energy dependence of personal monitors, exposure geometries, and the accompanying uncertainties. Those related to internal dose include sensitivity of bioassay methods, uncertainties in biokinetic models, appropriate dose coefficients, and modeling uncertainties. Compensation issues include uncertainties in the risk models and use of the 99th percentile of the distribution of probability of causation for awarding compensation. A review of the scientific literature and analysis of each of these issues distinguishes factors that play a major role in the compensation decision from those that do not. PMID:18545027

  6. 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

  7. 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. PMID:27115221

  8. Radiation dose and second breast cancer.

    PubMed Central

    Basco, V. E.; Coldman, A. J.; Elwood, J. M.; Young, M. E.

    1985-01-01

    Amongst 14,000 women with breast cancer treated between 1946 and 1982, 194 developed a second primary tumour in the contralateral breast more than one year after diagnosis of the first primary. The radiation dose to the contralateral breast was calculated for each member of this group and also for members of a control group matched for age, year of diagnosis and survival time. Comparison of the groups provides no evidence for radiation induced carcinogenesis on the contralateral breast in these patients. PMID:4041361

  9. 32 CFR 218.4 - Dose estimate reporting standards.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MISCELLANEOUS GUIDANCE FOR THE DETERMINATION AND REPORTING OF NUCLEAR RADIATION DOSE FOR DOD PARTICIPANTS IN THE... of the radiation environment to which the veteran was exposed and shall include inhaled, ingested... claimant's reconstructed dose? (e) Is there any recorded radiation exposure for the individual? Does...

  10. 32 CFR 218.4 - Dose estimate reporting standards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Dose estimate reporting standards. 218.4 Section... ATMOSPHERIC NUCLEAR TEST PROGRAM (1945-1962) § 218.4 Dose estimate reporting standards. The following minimum standards for reporting dose estimates shall be uniformly applied by the Military Services when...