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Sample records for dose dose equivalent

  1. New recommendations for dose equivalent

    International Nuclear Information System (INIS)

    Bengtsson, G.

    1985-01-01

    In its report 39, the International Commission on Radiation Units and Measurements (ICRU), has defined four new quantities for the determination of dose equivalents from external sources: the ambient dose equivalent, the directional dose equivalent, the individual dose equivalent, penetrating and the individual dose equivalent, superficial. The rationale behind these concepts and their practical application are discussed. Reference is made to numerical values of these quantities which will be the subject of a coming publication from the International Commission on Radiological Protection, ICRP. (Author)

  2. Dose sculpting with generalized equivalent uniform dose

    International Nuclear Information System (INIS)

    Wu Qiuwen; Djajaputra, David; Liu, Helen H.; Dong Lei; Mohan, Radhe; Wu, Yan

    2005-01-01

    With intensity-modulated radiotherapy (IMRT), a variety of user-defined dose distribution can be produced using inverse planning. The generalized equivalent uniform dose (gEUD) has been used in IMRT optimization as an alternative objective function to the conventional dose-volume-based criteria. The purpose of this study was to investigate the effectiveness of gEUD optimization to fine tune the dose distributions of IMRT plans. We analyzed the effect of gEUD-based optimization parameters on plan quality. The objective was to determine whether dose distribution to selected structures could be improved using gEUD optimization without adversely altering the doses delivered to other structures, as in sculpting. We hypothesized that by carefully defining gEUD parameters (EUD 0 and n) based on the current dose distributions, the optimization system could be instructed to search for alternative solutions in the neighborhood, and we could maintain the dose distributions for structures already satisfactory and improve dose for structures that need enhancement. We started with an already acceptable IMRT plan optimized with any objective function. The dose distribution was analyzed first. For structures that dose should not be changed, a higher value of n was used and EUD 0 was set slightly higher/lower than the EUD value at the current dose distribution for critical structures/targets. For structures that needed improvement in dose, a higher to medium value of n was used, and EUD 0 was set to the EUD value or slightly lower/higher for the critical structure/target at the current dose distribution. We evaluated this method in one clinical case each of head and neck, lung and prostate cancer. Dose volume histograms, isodose distributions, and relevant tolerance doses for critical structures were used for the assessment. We found that by adjusting gEUD optimization parameters, the dose distribution could be improved with only a few iterations. A larger value of n could lead to

  3. Absorbed Dose and Dose Equivalent Calculations for Modeling Effective Dose

    Science.gov (United States)

    Welton, Andrew; Lee, Kerry

    2010-01-01

    While in orbit, Astronauts are exposed to a much higher dose of ionizing radiation than when on the ground. It is important to model how shielding designs on spacecraft reduce radiation effective dose pre-flight, and determine whether or not a danger to humans is presented. However, in order to calculate effective dose, dose equivalent calculations are needed. Dose equivalent takes into account an absorbed dose of radiation and the biological effectiveness of ionizing radiation. This is important in preventing long-term, stochastic radiation effects in humans spending time in space. Monte carlo simulations run with the particle transport code FLUKA, give absorbed and equivalent dose data for relevant shielding. The shielding geometry used in the dose calculations is a layered slab design, consisting of aluminum, polyethylene, and water. Water is used to simulate the soft tissues that compose the human body. The results obtained will provide information on how the shielding performs with many thicknesses of each material in the slab. This allows them to be directly applicable to modern spacecraft shielding geometries.

  4. Editorial: New operational dose equivalent quantities

    International Nuclear Information System (INIS)

    Harvey, J.R.

    1985-01-01

    The ICRU Report 39 entitled ''Determination of Dose Equivalents Resulting from External Radiation Sources'' is briefly discussed. Four new operational dose equivalent quantities have been recommended in ICRU 39. The 'ambient dose equivalent' and the 'directional dose equivalent' are applicable to environmental monitoring and the 'individual dose equivalent, penetrating' and the 'individual dose equivalent, superficial' are applicable to individual monitoring. The quantities should meet the needs of day-to-day operational practice, while being acceptable to those concerned with metrological precision, and at the same time be used to give effective control consistent with current perceptions of the risks associated with exposure to ionizing radiations. (U.K.)

  5. Calculation methods for determining dose equivalent

    International Nuclear Information System (INIS)

    Endres, G.W.R.; Tanner, J.E.; Scherpelz, R.I.; Hadlock, D.E.

    1988-01-01

    A series of calculations of neutron fluence as a function of energy in an anthropomorphic phantom was performed to develop a system for determining effective dose equivalent for external radiation sources. critical organ dose equivalents are calculated and effective dose equivalents are determined using ICRP-26 methods. Quality factors based on both present definitions and ICRP-40 definitions are used in the analysis. The results of these calculations are presented and discussed

  6. Dose equivalent rate calculation tool for FBFC

    International Nuclear Information System (INIS)

    Porte, R.; Lengele, C.; Favier, Th.; Duval, A.

    2010-01-01

    The authors present the results obtained by a software designed to compute dose equivalent rate for the critical workstations of the FBFC plant in Romans, France, which will have to deal with an uranium more heavily loaded with U 232 . The uranium spectrum and the ageing time can be varied in order to visualize the evolution of the dose equivalent rate in different locations with respect to the ageing time

  7. A comparison of quantum limited dose and noise equivalent dose

    Science.gov (United States)

    Job, Isaias D.; Boyce, Sarah J.; Petrillo, Michael J.; Zhou, Kungang

    2016-03-01

    Quantum-limited-dose (QLD) and noise-equivalent-dose (NED) are performance metrics often used interchangeably. Although the metrics are related, they are not equivalent unless the treatment of electronic noise is carefully considered. These metrics are increasingly important to properly characterize the low-dose performance of flat panel detectors (FPDs). A system can be said to be quantum-limited when the Signal-to-noise-ratio (SNR) is proportional to the square-root of x-ray exposure. Recent experiments utilizing three methods to determine the quantum-limited dose range yielded inconsistent results. To investigate the deviation in results, generalized analytical equations are developed to model the image processing and analysis of each method. We test the generalized expression for both radiographic and fluoroscopic detectors. The resulting analysis shows that total noise content of the images processed by each method are inherently different based on their readout scheme. Finally, it will be shown that the NED is equivalent to the instrumentation-noise-equivalent-exposure (INEE) and furthermore that the NED is derived from the quantum-noise-only method of determining QLD. Future investigations will measure quantum-limited performance of radiographic panels with a modified readout scheme to allow for noise improvements similar to measurements performed with fluoroscopic detectors.

  8. Measurements of the personal dose equivalent

    International Nuclear Information System (INIS)

    Scarlat, F.; Scarisoreanu, A.; Badita, E.; Oane, M.; Mitru, E.

    2008-01-01

    Full text: The paper presents the results of measurements related to the personal dose equivalent in the rooms adjacent to NILPRP 7 MeV linear accelerator, by means of the secondary standard chamber T34035 Hp(10). The chamber was calibrated by PTB at S- 137 Cs (E av = 661.6 keV, T 1/2 11050 days) and has N H = 3.17x10 6 Sv/C calibration factor for the personal dose equivalent, Hp(10), at a depth of 10 mm in climatic reference conditions. The measurements were made for the two operation mode of the 7 MeV linac: electrons and bremsstrahlung

  9. Calculation of committed dose equivalent from intake of tritiated water

    International Nuclear Information System (INIS)

    Law, D.V.

    1978-08-01

    A new computerized method of calculating the committed dose equivalent from the intake of tritiated water at Harwell is described in this report. The computer program has been designed to deal with a variety of intake patterns and urine sampling schemes, as well as to produce committed dose equivalents corresponding to any periods for which individual monitoring for external radiation is undertaken. Details of retrospective doses are added semi-automatically to the Radiation Dose Records and committed dose equivalents are retained on a separate file. (author)

  10. Annual average equivalent dose of workers form health area

    International Nuclear Information System (INIS)

    Daltro, T.F.L.; Campos, L.L.

    1992-01-01

    The data of personnel monitoring during 1985 and 1991 of personnel that work in health area were studied, obtaining a general overview of the value change of annual average equivalent dose. Two different aspects were presented: the analysis of annual average equivalent dose in the different sectors of a hospital and the comparison of these doses in the same sectors in different hospitals. (C.G.C.)

  11. Committed dose equivalent in the practice of radiological protection

    International Nuclear Information System (INIS)

    Nenot, J.C.; Piechowski, J.

    1985-01-01

    In the case of internal exposure, the dose is not received at the moment of exposure, as happens with external exposure, since the incorporated radionuclide irradiates the various organs and tissues during the time it is present in the body. By definition, the committed dose equivalent corresponds to the received dose integrated over 50 years from the date of intake. In order to calculate it, one has to know the intake activity and the value of the committed dose equivalent per unit of intake activity. The uncertainties of the first parameter are such that the committed dose equivalent can only be regarded as an order of magnitude and not as a very accurate quantity. The use of it is justified, however, for, like the dose equivalent for external exposure, it expresses the risk of stochastic effects for the individual concerned since these effects, should they appear, would do so only after a latent period which is generally longer than the dose integration time. Moreover, the use of the committed dose equivalent offers certain advantages for dosimetric management, especially when it is simplified. A practical problem which may arise is that the annual dose limit is apparently exceeded by virtue of the fact that one is taking account, in the first year, of doses which will actually be received only in the following years. These problems are rare enough in practice to be dealt with individually in each case. (author)

  12. Effective dose equivalents from external radiation due to Chernobyl accident

    International Nuclear Information System (INIS)

    Erkin, V.G.; Debedev, O.V.; Balonov, M.I.; Parkhomenko, V.I.

    1992-01-01

    Summarized data on measurements of individual dose of external γ-sources in 1987-1990 of population of western areas of Bryansk region were presented. Type of distribution of effective dose equivalent, its significance for various professional and social groups of population depending on the type of the house was discussed. Dependences connecting surface soil activity in the populated locality with average dose of external radiation sources were presented. Tendency of dose variation in 1987-1990 was shown

  13. Neutrons in active proton therapy. Parameterization of dose and dose equivalent

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Uwe; Haelg, Roger A. [Univ. of Zurich (Switzerland). Dept. of Physics; Radiotherapy Hirslanden AG, Aarau (Switzerland); Lomax, Tony [Paul Scherrer Institute, Villigen (Switzerland). Center for Proton Therapy

    2017-08-01

    One of the essential elements of an epidemiological study to decide if proton therapy may be associated with increased or decreased subsequent malignancies compared to photon therapy is an ability to estimate all doses to non-target tissues, including neutron dose. This work therefore aims to predict for patients using proton pencil beam scanning the spatially localized neutron doses and dose equivalents. The proton pencil beam of Gantry 1 at the Paul Scherrer Institute (PSI) was Monte Carlo simulated using GEANT. Based on the simulated neutron dose and neutron spectra an analytical mechanistic dose model was developed. The pencil beam algorithm used for treatment planning at PSI has been extended using the developed model in order to calculate the neutron component of the delivered dose distribution for each treated patient. The neutron dose was estimated for two patient example cases. The analytical neutron dose model represents the three-dimensional Monte Carlo simulated dose distribution up to 85 cm from the proton pencil beam with a satisfying precision. The root mean square error between Monte Carlo simulation and model is largest for 138 MeV protons and is 19% and 20% for dose and dose equivalent, respectively. The model was successfully integrated into the PSI treatment planning system. In average the neutron dose is increased by 10% or 65% when using 160 MeV or 177 MeV instead of 138 MeV. For the neutron dose equivalent the increase is 8% and 57%. The presented neutron dose calculations allow for estimates of dose that can be used in subsequent epidemiological studies or, should the need arise, to estimate the neutron dose at any point where a subsequent secondary tumour may occur. It was found that the neutron dose to the patient is heavily increased with proton energy.

  14. Evaluation of effective dose equivalent from environmental gamma rays

    International Nuclear Information System (INIS)

    Saito, K.; Tsutsumi, M.; Moriuchi, S.; Petoussi, N.; Zankl, M.; Veit, R.; Jacob, P.; Drexler, G.

    1991-01-01

    Organ doses and effective dose equivalents for environmental gamma rays were calculated using human phantoms and Monte Carlo methods accounting rigorously the environmental gamma ray fields. It was suggested that body weight is the dominant factor to determine organ doses. The weight function expressing organ doses was introduced. Using this function, the variation in organ doses due to several physical factors were investigated. A detector having gamma-ray response similar to that of human bodies has been developed using a NaI(Tl) scintillator. (author)

  15. Minimum detectable dose equivalant of NTA film for fast neutron

    International Nuclear Information System (INIS)

    Ito, Masashi; Kumazawa, Shigeru; Nishi, Tatsuo; Numakunai, Takao

    1982-01-01

    A method has been studied of estimating the minimum detectable dose equivalent of fast neutrons for measurement of recoil proton tracks in NTA film. Poisson distribution was applied in estimation of the minimum detectable number of tracks. Factors such as sensitivity of the film for fast neutrons, energy dependency of the film response, and latent image fading of the tracks were taken into consideration in the estimation. The minimum detectable dose equivalent was affected by fluctuation in the number of tracks due to background radiation and degree of the affection depended on the measured area. The minimum detectable dose equivalent decreased with increasing the measuring area of background radiation even if the measuring area of neutron-irradiated film was small. The relation between the minimum detectable dose equivalent and the measuring area of neutron-irradiated film was obtained considering the effect of latent image fading. (author)

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

    International Nuclear Information System (INIS)

    Maruyama, Takashi; Nishizawa, Kanae; Kumamoto, Yoshikazu; Iwai, Kazuo; Mase, Naomichi.

    1993-01-01

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

  17. Verification of an effective dose equivalent model for neutrons

    International Nuclear Information System (INIS)

    Tanner, J.E.; Piper, R.K.; Leonowich, J.A.; Faust, L.G.

    1992-01-01

    Since the effective dose equivalent, based on the weighted sum of organ dose equivalents, is not a directly measurable quantity, it must be estimated with the assistance of computer modelling techniques and a knowledge of the incident radiation field. Although extreme accuracy is not necessary for radiation protection purposes, a few well chosen measurements are required to confirm the theoretical models. Neutron doses and dose equivalents were measured in a RANDO phantom at specific locations using thermoluminescence dosemeters, etched track dosemeters, and a 1.27 cm (1/2 in) tissue-equivalent proportional counter. The phantom was exposed to a bare and a D 2 O-moderated 252 Cf neutron source at the Pacific Northwest Laboratory's Low Scatter Facility. The Monte Carlo code MCNP with the MIRD-V mathematical phantom was used to model the human body and to calculate the organ doses and dose equivalents. The experimental methods are described and the results of the measurements are compared with the calculations. (author)

  18. Verification of an effective dose equivalent model for neutrons

    International Nuclear Information System (INIS)

    Tanner, J.E.; Piper, R.K.; Leonowich, J.A.; Faust, L.G.

    1991-10-01

    Since the effective dose equivalent, based on the weighted sum of organ dose equivalents, is not a directly measurable quantity, it must be estimated with the assistance of computer modeling techniques and a knowledge of the radiation field. Although extreme accuracy is not necessary for radiation protection purposes, a few well-chosen measurements are required to confirm the theoretical models. Neutron measurements were performed in a RANDO phantom using thermoluminescent dosemeters, track etch dosemeters, and a 1/2-in. (1.27-cm) tissue equivalent proportional counter in order to estimate neutron doses and dose equivalents within the phantom at specific locations. The phantom was exposed to bare and D 2 O-moderated 252 Cf neutrons at the Pacific Northwest Laboratory's Low Scatter Facility. The Monte Carlo code MCNP with the MIRD-V mathematical phantom was used to model the human body and calculate organ doses and dose equivalents. The experimental methods are described and the results of the measurements are compared to the calculations. 8 refs., 3 figs., 3 tabs

  19. A comparison of the angular dependence of effective dose and effective dose equivalent

    International Nuclear Information System (INIS)

    Sitek, M.A.; Gierga, D.P.; Xu, X.G.

    1996-01-01

    In ICRP (International Commission on Radiological Protection) Publication 60, the set of critical organs and their weighing factors were changed, defining the quantity effective dose, E. This quantity replaced the effective dose equivalent, H E , as defined by ICRP 26. Most notably, the esophagus was added to the list of critical organs. The Monte Carlo neutron/photon transport code MCNP was used to determine the effective dose to sex-specific anthropomorphic phantoms. The phantoms, developed in previous research, were modified to include the esophagus. Monte Carlo simulations were performed for monoenergetic photon beams of energies 0.08 MeV, 0.3 MeV, and 1.0 MeV for various azimuthal and polar angles. Separate organ equivalent doses were determined for male and female phantoms. The resulting organ equivalent doses were calculated from arithmetic mean averages. The angular dependence of effective dose was compared with that of effective dose equivalent reported in previous research. The differences between the two definitions and possible implications to regulatory agencies were summarized

  20. Committed equivalent organ doses and committed effective doses from intakes of radionuclides

    CERN Document Server

    Phipps, A W; Kendall, G M; Silk, T J; Stather, J W

    1991-01-01

    This report contains details of committed equivalent doses to individual organs for intakes by ingestion and inhalation of 1 mu m AMAD particles of 359 nuclides by infants aged 3 months, by children aged 1, 5, 10 and 15 years, and by adults. It complements NRPB-R245 which describes the changes which have taken place since the last NRPB compendium of dose per unit intake factors (dose coefficients) and gives summary tables. Information on the way committed doses increase with the integration period is given in NRPB-M289. The information given in these memoranda is also available as a microcomputer package - NRPB-SR245.

  1. Skin Dose Equivalent Measurement from Neutron-Deficient Isotopes

    International Nuclear Information System (INIS)

    Hsu, Hsiao-Hua; Costigan, Steve A.; Romero, Leonard L.; Whicker, Jeffrey J.

    1997-12-01

    Neutron-deficient-isotopes decay via positron emission and/or electron capture often followed by x-ray, gamma-ray, and 0.511 MeV photons from positron annihilation. For cases of significant area and/or personnel contamination with these isotopes, determination of skin dose equivalent (SDE) is required by 10CFR835. For assessment of SDE, we evaluated the MICROSPEC-2(TM) system manufactured by Bubble Technology Industries of Canada which uses three different probes for dose measurement. We used two probes: (1) the X-probe which measures lower energy (4 - 120 keV) photon energy distributions and determines deep dose equivalent, SDE and dose equivalent to eyes, and (2) the B-probe which measures electron (positron) energy distributions, and determines skin dose equivalent. Also, the measured photon and beta spectra can be used to identify radioactive isotopes in the contaminated area. Measurements with several neutron-deficient sources showed that this system provided reasonably accurate SDE rate measurements when compared with calculated benchmark SDE rates with an average percent difference of 40%. Variations were expected because of differences between the assumed geometries used by MlCROSPEC-2 and the calculations when compared to the measurement conditions

  2. Skin Dose Equivalent Measurement from Neutron-Deficient Isotopes.

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Hsiao-Hua; Costigan, Steve A.; Romero, Leonard L.; Whicker, Jeffrey J.

    1997-12-31

    Neutron-deficient-isotopes decay via positron emission and/or electron capture often followed by x-ray, gamma-ray, and 0.511 MeV photons from positron annihilation. For cases of significant area and/or personnel contamination with these isotopes, determination of skin dose equivalent (SDE) is required by 10CFR835. For assessment of SDE, we evaluated the MICROSPEC-2(TM) system manufactured by Bubble Technology Industries of Canada which uses three different probes for dose measurement. We used two probes: (1) the X-probe which measures lower energy (4 - 120 keV) photon energy distributions and determines deep dose equivalent, SDE and dose equivalent to eyes, and (2) the B-probe which measures electron (positron) energy distributions, and determines skin dose equivalent. Also, the measured photon and beta spectra can be used to identify radioactive isotopes in the contaminated area. Measurements with several neutron-deficient sources showed that this system provided reasonably accurate SDE rate measurements when compared with calculated benchmark SDE rates with an average percent difference of 40%. Variations were expected because of differences between the assumed geometries used by MlCROSPEC-2 and the calculations when compared to the measurement conditions.

  3. Is the dose equivalent index a quantity to be measured

    International Nuclear Information System (INIS)

    Wagner, S.R.

    1980-01-01

    The following modifying factors are briefly considered in relation to the ambiguities and limitations of the Dose Equivalent Index: 1) Variations with time or of the movement of the exposed person 2) Irradiation geometry 3) Effect of radiation energy 4) Instrument performance and calibration, and other operational quantities. (U.K.)

  4. BH3105 type neutron dose equivalent meter of high sensitivity

    International Nuclear Information System (INIS)

    Ji Changsong; Zhang Enshan; Yang Jianfeng; Zhang Hong; Huang Jiling

    1995-10-01

    It is noted that to design a neutron dose meter of high sensitivity is almost impossible in the frame of traditional designing principle--'absorption net principle'. Based on a newly proposed principle of obtaining neutron dose equi-biological effect adjustment--' absorption stick principle', a brand-new neutron dose-equivalent meter with high neutron sensitivity BH3105 has been developed. Its sensitivity reaches 10 cps/(μSv·h -1 ), which is 18∼40 times higher than one of foreign products of the same kind and is 10 4 times higher than that of domestic FJ342 neutron rem-meter. BH3105 has a measurement range from 0.1μSv/h to 1 Sv/h which is 1 or 2 orders wider than that of the other's. It has the advanced properties of gamma-resistance, energy response, orientation, etc. (6 tabs., 5 figs.)

  5. Comparison of organ dose and dose equivalent for human phantoms of CAM vs. MAX

    Science.gov (United States)

    Kim, Myung-Hee Y.; Qualls, Garry D.; Slaba, Tony C.; Cucinotta, Francis A.

    2010-04-01

    For the evaluation of organ dose and dose equivalent of astronauts on space shuttle and the International Space Station (ISS) missions, the CAMERA models of CAM (Computerized Anatomical Male) and CAF (Computerized Anatomical Female) of human tissue shielding have been implemented and used in radiation transport model calculations at NASA. One of new human geometry models to meet the “reference person” of International Commission on Radiological Protection (ICRP) is based on detailed Voxel (volumetric and pixel) phantom models denoted for male and female as MAX (Male Adult voXel) and FAX (Female Adult voXel), respectively. We compared the CAM model predictions of organ doses to those of MAX model, since the MAX model represents the male adult body with much higher fidelity than the CAM model currently used at NASA. Directional body-shielding mass was evaluated for over 1500 target points of MAX for specified organs considered to be sensitive to the induction of stochastic effects. Radiation exposures to solar particle event (SPE), trapped protons, and galactic cosmic ray (GCR) were assessed at the specific sites in the MAX phantom by coupling space radiation transport models with the relevant body-shielding mass. The development of multiple-point body-shielding distributions at each organ made it possible to estimate the mean and variance of organ doses at the specific organ. For the estimate of doses to the blood forming organs (BFOs), data on active marrow distributions in adult were used to weight the bone marrow sites over the human body. The discrete number of target points of MAX organs resulted in a reduced organ dose and dose equivalent compared to the results of CAM organs especially for SPE, and should be further investigated. Differences of effective doses between the two approaches were found to be small (<5%) for GCR.

  6. Determination of dose equivalent and risk in thorium cycle

    International Nuclear Information System (INIS)

    Ney, C.L.V.N.

    1988-01-01

    In these report are presented the calculations of dose equivalent and risk, utilizing the dosimetric model described in publication 30 of the International Comission on Radiological Protection. This information was obtained by the workers of the thorium cycle, employed at the Praia and Santo Amaro Facilities, by assessing the quantity and concentration of thorium in the air. The samples and the number of measurements were established through design of experiments techniques, and the results were evaluated with the aid of variance analysis. The estimater of dose equivalent for internal and external radiation exposure and risk associated were compared with the maximum recommended limits. The results indicate the existence of operation areas whose values were above those limits, requiring so an improvement in the procedures and services in order to meet the requirements of the radiological protetion. (author) [pt

  7. Dose equivalent distribution during occupational exposure in oncology

    International Nuclear Information System (INIS)

    Marco H, J.

    1996-01-01

    In this work are presented the results of the radiological surveillance of occupationally exposed workers at the National Institute of Oncology and Radiology during 26 years. The incidence of the equivalent dose in the personal working with radiant sources and radioactive substances in areas of x rays diagnostic, teletherapy, brachytherapy, nuclear medicine and biomedical research was showed. The employed dosimetric system makes use of ORWO RD3/RD4 monitoring film with copper and lead filters inside a plastic cassette manufactured in Cuba. The experimental method is supported by the optical densitometric analysis of films together with a set of standard film calibrated in standard X and gamma photon beams by means of a secondary standard dosimeter, type NPL. Statistics show that except those workings with radium-226, manual brachytherapy or Mo-99/Tc-99 generator elution, the equivalent dose distribution in our workers has been kept in regions well down the annual permissible limit. (authors). 6 refs., 3 tabs

  8. Development of a neutron personal dose equivalent detector

    International Nuclear Information System (INIS)

    Tsujimura, N.; Yoshida, T.; Takada, C.; Momose, T.; Nunomiya, T.; Aoyama, K.

    2007-01-01

    A new neutron-measuring instrument that is intended to measure a neutron personal dose equivalent, H p (10) was developed. This instrument is composed of two parts: (1) a conventional moderator-based neutron dose equivalent meter and (2) a neutron shield made of borated polyethylene, which covers a backward hemisphere to adjust the angular dependence. The whole design was determined on the basis of MCNP calculations so as to have response characteristics that would generally match both the energy and angular dependencies of H p (10). This new instrument will be a great help in assessing the reference values of neutron H p (10) during field testing of personal neutron dosemeters in workplaces and also in interpreting their readings. (authors)

  9. The radiobiology of boron neutron capture therapy: Are ''photon-equivalent'' doses really photon-equivalent?

    International Nuclear Information System (INIS)

    Coderre, J.A.; Diaz, A.Z.; Ma, R.

    2001-01-01

    Boron neutron capture therapy (BNCT) produces a mixture of radiation dose components. The high-linear energy transfer (LET) particles are more damaging in tissue than equal doses of low-LET radiation. Each of the high-LET components can multiplied by an experimentally determined factor to adjust for the increased biological effectiveness and the resulting sum expressed in photon-equivalent units (Gy-Eq). BNCT doses in photon-equivalent units are based on a number of assumptions. It may be possible to test the validity of these assumptions and the accuracy of the calculated BNCT doses by 1) comparing the effects of BNCT in other animal or biological models where the effects of photon radiation are known, or 2) if there are endpoints reached in the BNCT dose escalation clinical trials that can be related to the known response to photons of the tissue in question. The calculated Gy-Eq BNCT doses delivered to dogs and to humans with BPA and the epithermal neutron beam of the Brookhaven Medical Research Reactor were compared to expected responses to photon irradiation. The data indicate that Gy-Eq doses in brain may be underestimated. Doses to skin are consistent with the expected response to photons. Gy-Eq doses to tumor are significantly overestimated. A model system of cells in culture irradiated at various depths in a lucite phantom using the epithermal beam is under development. Preliminary data indicate that this approach can be used to detect differences in the relative biological effectiveness of the beam. The rat 9L gliosarcoma cell survival data was converted to photon-equivalent doses using the same factors assumed in the clinical studies. The results superimposed on the survival curve derived from irradiation with Cs-137 photons indicating the potential utility of this model system. (author)

  10. Assessment of organ equivalent doses and effective doses from diagnostic X-ray examinations

    International Nuclear Information System (INIS)

    Park, Sang Hyun

    2003-02-01

    The MIRD-type adult male, female and age 10 phantoms were constructed to evaluate organ equivalent dose and effective dose of patient due to typical diagnostic X-ray examination. These phantoms were constructed with external and internal dimensions of Korean. The X-ray energy spectra were generated with SPEC78. MCNP4B ,the general-purposed Monte Carlo code, was used. Information of chest PA , chest LAT, and abdomen AP diagnostic X-ray procedures was collected on the protocol of domestic hospitals. The results showed that patients pick up approximate 0.02 to 0.18 mSv of effective dose from a single chest PA examination, and 0.01 to 0.19 mSv from a chest LAT examination depending on the ages. From an abdomen AP examination, patients pick up 0.17 to 1.40 mSv of effective dose. Exposure time, organ depth from the entrance surface and X-ray beam field coverage considerably affect the resulting doses. Deviation among medical institutions is somewhat high, and this indicated that medical institutions should interchange their information and the need of education for medical staff. The methodology and the established system can be applied, with some expansion, to dose assessment for other medical procedures accompanying radiation exposure of patients like nuclear medicine or therapeutic radiology

  11. Method to account for dose fractionation in analysis of IMRT plans: Modified equivalent uniform dose

    International Nuclear Information System (INIS)

    Park, Clinton S.; Kim, Yongbok; Lee, Nancy; Bucci, Kara M.; Quivey, Jeanne M.; Verhey, Lynn J.; Xia Ping

    2005-01-01

    Purpose: To propose a modified equivalent uniform dose (mEUD) to account for dose fractionation using the biologically effective dose without losing the advantages of the generalized equivalent uniform dose (gEUD) and to report the calculated mEUD and gEUD in clinically used intensity-modulated radiotherapy (IMRT) plans. Methods and Materials: The proposed mEUD replaces the dose to each voxel in the gEUD formulation by a biologically effective dose with a normalization factor. We propose to use the term mEUD D o /n o that includes the total dose (D o ) and number of fractions (n o ) and to use the term mEUD o that includes the same total dose but a standard fraction size of 2 Gy. A total of 41 IMRT plans for patients with nasopharyngeal cancer treated at our institution between October 1997 and March 2002 were selected for the study. The gEUD and mEUD were calculated for the planning gross tumor volume (pGTV), planning clinical tumor volume (pCTV), parotid glands, and spinal cord. The prescription dose for these patients was 70 Gy to >95% of the pGTV and 59.4 Gy to >95% of the pCTV in 33 fractions. Results: The calculated average gEUD was 72.2 ± 2.4 Gy for the pGTV, 54.2 ± 7.1 Gy for the pCTV, 26.7 ± 4.2 Gy for the parotid glands, and 34.1 ± 6.8 Gy for the spinal cord. The calculated average mEUD D o /n o using 33 fractions was 71.7 ± 3.5 Gy for mEUD 70/33 of the pGTV, 49.9 ± 7.9 Gy for mEUD 59.5/33 of the pCTV, 27.6 ± 4.8 Gy for mEUD 26/33 of the parotid glands, and 32.7 ± 7.8 Gy for mEUD 45/33 of the spinal cord. Conclusion: The proposed mEUD, combining the gEUD with the biologically effective dose, preserves all advantages of the gEUD while reflecting the fractionation effects and linear and quadratic survival characteristics

  12. On the calibration of photon dosemeters in the equivalent dose units

    International Nuclear Information System (INIS)

    Bregadze, Yu.I.; Isaev, B.M.; Maslyaev, P.F.

    1980-01-01

    General aspects of transition from exposure dose of photo radiation to equivalent one are considered. By determination the equivalent dose is a function of point location in an irradiated object, that is why it is necessary to know equivalent dose distribution in the human body for uniform description of the risk degree. The international electrotechnical comission recommends to measure equivalent doses at 7 and 800 mg/cm 2 depths in a tissue-equivalent ball with 30 cm diameter, calling them skin equivalent dose and depth equivalent dose, respectively, and to compare them with the permissible 500 mZ and 50 mZ a year, respectively. Practical transition to using equivalent dose for evaluation of radiation danger of being in photon radiation field of low energy should include measures on regraduating already produced dose meters, graduating the dose meters under production and developing the system of their metrologic supply [ru

  13. Measurement of ambient dose equivalent H*(10) and directional dose equivalent H'(0.07) with pocket sized survey meters

    International Nuclear Information System (INIS)

    Iwatschenko, Michael

    2008-01-01

    Full text: In many parts of the world, predominantly in Europe, small sized survey meters based on Geiger-Mueller or proportional counters are widely used for dose rate and dose equivalent rate measurements, while in other regions, especially in the U.S., ionisation chambers are preferred for this task. This paper tries to shed some light on the likely reasons for these two diverging instrumental inclinations. Their respective strengths and weaknesses is analyzed in respect to energy response, dose rate measuring range, size, weight and susceptibility to environmental influences. Furthermore the response and limitations regarding the measurement of pulsed radiation (medical X-ray and CT-devices, accelerators, non-destructive testing) is discussed. A newly developed pocket size instrument based on a pan-cake Geiger-Mueller tube is used as an example to explain the capability and flexibility of modern survey meters. The RadEye B20 is a compact multi-purpose dose rate meter and contamination meter for alpha, beta, gamma and X-ray radiation. By virtue of carefully designed multi-layer gamma energy filters, H*(10) (deep dose) or H'(0,07) (shallow dose) measurements from 17 - 1300 keV can be performed. The instrument can even be worn in a belt holster, so that the impact to the mobility of the user is minimized. For emergency response purposes alpha and beta contamination can be discriminated using another optional filter; a simple sample changer adapter can extend the scope of application. Immediate and reproducible counter measurements, e.g. of smear tests can be performed locally. (author)

  14. Response of radiation monitors for ambient dose equivalent, H*(10)

    International Nuclear Information System (INIS)

    Grecco, Claudio Henrique dos Santos

    2001-01-01

    Radiation monitors are used all over the world to evaluate if places with presence of ionising radiation present safe conditions for people. Radiation monitors should be tested according to international or national standards in order to be qualified for use. This work describes a methodology and procedures to evaluate the energy and angular responses of any radiation monitor for ambient dose equivalent, H*(10), according to the recommendations of ISO and IEC standards. The methodology and the procedures were applied to the Monitor Inteligente de Radiacao MIR 7026, developed by the Instituto em Engenharia Nuclear (IEN), to evaluate and to adjust its response for H*(10), characterizing it as an ambient dose equivalent meter. The tests were performed at the Laboratorio Nacional de Metrologia das Radiacoes Ionizantes (LNMRI), at Instituto de Radioprotecao e Dosimetria (IRD), and results showed that the Monitor Inteligente de Radiacao MIR 7026 can be used as an EI*(10) meter, in accordance to the IEC 60846 standard requirements. The overall estimated uncertainty for the determination of the MIR 7026 response, in all radiation qualities used in this work, was 4,5 % to a 95 % confidence limit. (author)

  15. Experimental method research on neutron equal dose-equivalent detection

    International Nuclear Information System (INIS)

    Ji Changsong

    1995-10-01

    The design principles of neutron dose-equivalent meter for neutron biological equi-effect detection are studied. Two traditional principles 'absorption net principle' and 'multi-detector principle' are discussed, and on the basis of which a new theoretical principle for neutron biological equi-effect detection--'absorption stick principle' has been put forward to place high hope on both increasing neutron sensitivity of this type of meters and overcoming the shortages of the two traditional methods. In accordance with this new principle a brand-new model of neutron dose-equivalent meter BH3105 has been developed. Its neutron sensitivity reaches 10 cps/(μSv·h -1 ), 18∼40 times higher than that of all the same kinds of meters 0.23∼0.56 cps/(μSv·h -1 ), available today at home and abroad and the specifications of the newly developed meter reach or surpass the levels of the same kind of meters. Therefore the new theoretical principle of neutron biological equi-effect detection--'absorption stick principle' is proved to be scientific, advanced and useful by experiments. (3 refs., 3 figs., 2 tabs.)

  16. Quartz red TL SAR equivalent dose overestimation for Chinese loess

    DEFF Research Database (Denmark)

    Lai, Z.P.; Murray, A.S.; Bailey, R.M.

    2006-01-01

    For the red TL of quartz extracted from Chinese loess, the single-aliquot regenerative-dose (SAR) procedure overestimates the known laboratory doses in dose recovery test. The overestimation is the result of the first heating during the measurement of natural TL signal causing a sensitivity...

  17. Equivalent dose determination using a quartz isothermal TL signal

    DEFF Research Database (Denmark)

    Vandenberghe, D.A.G.; Jain, Mayank; Murray, A.S.

    2009-01-01

    signal can be fully reset by sunlight, and grows with dose over at least the same range as the OSL signal. A single-aliquot regenerative-dose (SAR) protocol can be used with this ITL signal. Dose recovery experiments confirm the suitability of the measurement protocol; the De values are in acceptable...... agreement with the expected burial dose in samples from a variety of depositional environments and ages. Our results suggest that measurement of the ITL signal at 270 °C enables the quartz 325 °C TL peak to be used for accurate dose measurements on a single aliquot. The signal allows dating over at least...

  18. Determination of skin dose reduction by lead equivalent gloves

    International Nuclear Information System (INIS)

    Norriza Mohd Isa; Abd Aziz Mhd Ramli

    2006-01-01

    Radiation protective gloves are always used in medical facilities to protect radiation workers from unnecessary radiation exposure. A study on radiation protection gloves which are produced by local company had been performed by the Medical Physics Group, MINT. The gloves were made of lead equivalent material, as the attenuating element. The gloves were evaluated in term of the percentage of skin dose reduction by using a newly developed procedure and facilities in MINT. Attenuation measurements of the gloves had been carried out using direct beams and scattered radiations of different qualities. TLD rings were fitted on finger phantom; and water phantom were used in the measurement. The result were obtained and analysed based on data supplied by manufacturer. (Author)

  19. Equivalent dose determination in foraminifera: analytical description of the CO{sub 2}{sup -}-signal dose-response curve

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, D. E-mail: dirk.hoffmann@iup.uni-heidelberg.de; Woda, C.; Mangini, A

    2003-02-01

    The dose-response of the CO{sub 2}{sup -}signal (g=2.0006) in foraminifera with ages between 19 and 300 ka is investigated. The sum of two exponential saturation functions is an adequate function to describe the dose-response curve up to an additional dose of 8000 Gy. It yields excellent dating results but requires an artificial doses of at least 5000 Gy. For small additional doses of about 500 Gy the single exponential saturation function can be used to calculate a reliable equivalent dose D{sub E}, although it does not describ the dose-response for higher doses. The CO{sub 2}{sup -}-signal dose-response indicates that the signal has two components of which one is less stable than the other.

  20. Risk equivalent of exposure versus dose of radiation

    International Nuclear Information System (INIS)

    Bond, V.P.

    1986-01-01

    This report describes a risk analysis study of low-dose irradiation and the resulting biological effects on a cell. The author describes fundamental differences between the effects of high-level exposure (HLE) and low-level exposure (LLE). He stresses that the concept of absorbed dose to an organ is not a dose but a level of effect produced by a particular number of particles. He discusses the confusion between a linear-proportional representation of dose limits and a threshold-curvilinear representation, suggesting that a LLE is a composite of both systems

  1. The Use Of Optical Properties Of Cr-39 In Alpha Particle Equivalent Dose Measurements

    International Nuclear Information System (INIS)

    Shnishin, K.A.

    2007-01-01

    In this work, optical properties of alpha irradiated Cr-39 were measured as a function of optical photon wavelength from 200-1100 nm. Optical energy gap and optical absorption at finite wavelength was also calculated and correlated to alpha fluence and dose equivalent. Alpha doses were calculated from the corresponding irradiation fluence and specific energy loss using TRIM computer program. It was found that, the optical absorption of unattached Cr-39 was varied with alpha fluence and corresponding equivalent doses. Also the optical energy gab was varied with fluence and dose equivalent of alpha particles. This work introduces a reasonably simple method for the Rn dose equivalent calculation by Cr-39 track

  2. Application of combined TLD and CR-39 PNTD method for measurement of total dose and dose equivalent on ISS

    Energy Technology Data Exchange (ETDEWEB)

    Benton, E.R. [Eril Research, Inc., Stillwater, Oklahoma (United States); Deme, S.; Apathy, I. [KFKI Atomic Energy Research Institute, Budapest (Hungary)

    2006-07-01

    To date, no single passive detector has been found that measures dose equivalent from ionizing radiation exposure in low-Earth orbit. We have developed the I.S.S. Passive Dosimetry System (P.D.S.), utilizing a combination of TLD in the form of the self-contained Pille TLD system and stacks of CR-39 plastic nuclear track detector (P.N.T.D.) oriented in three mutually orthogonal directions, to measure total dose and dose equivalent aboard the International Space Station (I.S.S.). The Pille TLD system, consisting on an on board reader and a large number of Ca{sub 2}SO{sub 4}:Dy TLD cells, is used to measure absorbed dose. The Pille TLD cells are read out and annealed by the I.S.S. crew on orbit, such that dose information for any time period or condition, e.g. for E.V.A. or following a solar particle event, is immediately available. Near-tissue equivalent CR-39 P.N.T.D. provides Let spectrum, dose, and dose equivalent from charged particles of LET{sub {infinity}}H{sub 2}O {>=} 10 keV/{mu}m, including the secondaries produced in interactions with high-energy neutrons. Dose information from CR-39 P.N.T.D. is used to correct the absorbed dose component {>=} 10 keV/{mu}m measured in TLD to obtain total dose. Dose equivalent from CR-39 P.N.T.D. is combined with the dose component <10 keV/{mu}m measured in TLD to obtain total dose equivalent. Dose rates ranging from 165 to 250 {mu}Gy/day and dose equivalent rates ranging from 340 to 450 {mu}Sv/day were measured aboard I.S.S. during the Expedition 2 mission in 2001. Results from the P.D.S. are consistent with those from other passive detectors tested as part of the ground-based I.C.C.H.I.B.A.N. intercomparison of space radiation dosimeters. (authors)

  3. Application of combined TLD and CR-39 PNTD method for measurement of total dose and dose equivalent on ISS

    International Nuclear Information System (INIS)

    Benton, E.R.; Deme, S.; Apathy, I.

    2006-01-01

    To date, no single passive detector has been found that measures dose equivalent from ionizing radiation exposure in low-Earth orbit. We have developed the I.S.S. Passive Dosimetry System (P.D.S.), utilizing a combination of TLD in the form of the self-contained Pille TLD system and stacks of CR-39 plastic nuclear track detector (P.N.T.D.) oriented in three mutually orthogonal directions, to measure total dose and dose equivalent aboard the International Space Station (I.S.S.). The Pille TLD system, consisting on an on board reader and a large number of Ca 2 SO 4 :Dy TLD cells, is used to measure absorbed dose. The Pille TLD cells are read out and annealed by the I.S.S. crew on orbit, such that dose information for any time period or condition, e.g. for E.V.A. or following a solar particle event, is immediately available. Near-tissue equivalent CR-39 P.N.T.D. provides Let spectrum, dose, and dose equivalent from charged particles of LET ∞ H 2 O ≥ 10 keV/μm, including the secondaries produced in interactions with high-energy neutrons. Dose information from CR-39 P.N.T.D. is used to correct the absorbed dose component ≥ 10 keV/μm measured in TLD to obtain total dose. Dose equivalent from CR-39 P.N.T.D. is combined with the dose component <10 keV/μm measured in TLD to obtain total dose equivalent. Dose rates ranging from 165 to 250 μGy/day and dose equivalent rates ranging from 340 to 450 μSv/day were measured aboard I.S.S. during the Expedition 2 mission in 2001. Results from the P.D.S. are consistent with those from other passive detectors tested as part of the ground-based I.C.C.H.I.B.A.N. intercomparison of space radiation dosimeters. (authors)

  4. Out‐of‐field doses and neutron dose equivalents for electron beams from modern Varian and Elekta linear accelerators

    Science.gov (United States)

    Cardenas, Carlos E.; Nitsch, Paige L.; Kudchadker, Rajat J.; Howell, Rebecca M.

    2016-01-01

    Out‐of‐field doses from radiotherapy can cause harmful side effects or eventually lead to secondary cancers. Scattered doses outside the applicator field, neutron source strength values, and neutron dose equivalents have not been broadly investigated for high‐energy electron beams. To better understand the extent of these exposures, we measured out‐of‐field dose characteristics of electron applicators for high‐energy electron beams on two Varian 21iXs, a Varian TrueBeam, and an Elekta Versa HD operating at various energy levels. Out‐of‐field dose profiles and percent depth‐dose curves were measured in a Wellhofer water phantom using a Farmer ion chamber. Neutron dose was assessed using a combination of moderator buckets and gold activation foils placed on the treatment couch at various locations in the patient plane on both the Varian 21iX and Elekta Versa HD linear accelerators. Our findings showed that out‐of‐field electron doses were highest for the highest electron energies. These doses typically decreased with increasing distance from the field edge but showed substantial increases over some distance ranges. The Elekta linear accelerator had higher electron out‐of‐field doses than the Varian units examined, and the Elekta dose profiles exhibited a second dose peak about 20 to 30 cm from central‐axis, which was found to be higher than typical out‐of‐field doses from photon beams. Electron doses decreased sharply with depth before becoming nearly constant; the dose was found to decrease to a depth of approximately E(MeV)/4 in cm. With respect to neutron dosimetry, Q values and neutron dose equivalents increased with electron beam energy. Neutron contamination from electron beams was found to be much lower than that from photon beams. Even though the neutron dose equivalent for electron beams represented a small portion of neutron doses observed under photon beams, neutron doses from electron beams may need to be considered for

  5. Out-of-field doses and neutron dose equivalents for electron beams from modern Varian and Elekta linear accelerators.

    Science.gov (United States)

    Cardenas, Carlos E; Nitsch, Paige L; Kudchadker, Rajat J; Howell, Rebecca M; Kry, Stephen F

    2016-07-08

    Out-of-field doses from radiotherapy can cause harmful side effects or eventually lead to secondary cancers. Scattered doses outside the applicator field, neutron source strength values, and neutron dose equivalents have not been broadly investigated for high-energy electron beams. To better understand the extent of these exposures, we measured out-of-field dose characteristics of electron applicators for high-energy electron beams on two Varian 21iXs, a Varian TrueBeam, and an Elekta Versa HD operating at various energy levels. Out-of-field dose profiles and percent depth-dose curves were measured in a Wellhofer water phantom using a Farmer ion chamber. Neutron dose was assessed using a combination of moderator buckets and gold activation foils placed on the treatment couch at various locations in the patient plane on both the Varian 21iX and Elekta Versa HD linear accelerators. Our findings showed that out-of-field electron doses were highest for the highest electron energies. These doses typically decreased with increasing distance from the field edge but showed substantial increases over some distance ranges. The Elekta linear accelerator had higher electron out-of-field doses than the Varian units examined, and the Elekta dose profiles exhibited a second dose peak about 20 to 30 cm from central-axis, which was found to be higher than typical out-of-field doses from photon beams. Electron doses decreased sharply with depth before becoming nearly constant; the dose was found to decrease to a depth of approximately E(MeV)/4 in cm. With respect to neutron dosimetry, Q values and neutron dose equivalents increased with electron beam energy. Neutron contamination from electron beams was found to be much lower than that from photon beams. Even though the neutron dose equivalent for electron beams represented a small portion of neutron doses observed under photon beams, neutron doses from electron beams may need to be considered for special cases.

  6. Dose equivalent rate constants and barrier transmission data for nuclear medicine facility dose calculations and shielding design.

    Science.gov (United States)

    Kusano, Maggie; Caldwell, Curtis B

    2014-07-01

    A primary goal of nuclear medicine facility design is to keep public and worker radiation doses As Low As Reasonably Achievable (ALARA). To estimate dose and shielding requirements, one needs to know both the dose equivalent rate constants for soft tissue and barrier transmission factors (TFs) for all radionuclides of interest. Dose equivalent rate constants are most commonly calculated using published air kerma or exposure rate constants, while transmission factors are most commonly calculated using published tenth-value layers (TVLs). Values can be calculated more accurately using the radionuclide's photon emission spectrum and the physical properties of lead, concrete, and/or tissue at these energies. These calculations may be non-trivial due to the polyenergetic nature of the radionuclides used in nuclear medicine. In this paper, the effects of dose equivalent rate constant and transmission factor on nuclear medicine dose and shielding calculations are investigated, and new values based on up-to-date nuclear data and thresholds specific to nuclear medicine are proposed. To facilitate practical use, transmission curves were fitted to the three-parameter Archer equation. Finally, the results of this work were applied to the design of a sample nuclear medicine facility and compared to doses calculated using common methods to investigate the effects of these values on dose estimates and shielding decisions. Dose equivalent rate constants generally agreed well with those derived from the literature with the exception of those from NCRP 124. Depending on the situation, Archer fit TFs could be significantly more accurate than TVL-based TFs. These results were reflected in the sample shielding problem, with unshielded dose estimates agreeing well, with the exception of those based on NCRP 124, and Archer fit TFs providing a more accurate alternative to TVL TFs and a simpler alternative to full spectral-based calculations. The data provided by this paper should assist

  7. Investigation of 1-cm dose equivalent for photons behind shielding materials

    International Nuclear Information System (INIS)

    Hirayama, Hideo; Tanaka, Shun-ichi

    1991-03-01

    The ambient dose equivalent at 1-cm depth, assumed equivalent to the 1-cm dose equivalent in practical dose estimations behind shielding slabs of water, concrete, iron or lead for normally incident photons having various energies was calculated by using conversion factors for a slab phantom. It was compared with the 1-cm depth dose calculated with the Monte Carlo code EGS4. It was concluded from this comparison that the ambient dose equivalent calculated by using the conversion factors for the ICRU sphere could be used for the evaluation of the 1-cm dose equivalent for the sphere phantom within 20% errors. Average and practical conversion factors are defined as the conversion factors from exposure to ambient dose equivalent in a finite slab or an infinite one, respectively. They were calculated with EGS4 and the discrete ordinates code PALLAS. The exposure calculated with simple estimation procedures such as point kernel methods can be easily converted to ambient dose equivalent by using these conversion factors. The maximum value between 1 and 30 mfp can be adopted as the conversion factor which depends only on material and incident photon energy. This gives the ambient dose equivalent on the safe side. 13 refs., 7 figs., 2 tabs

  8. Dose equivalent response of personal neutron dosemeters as a function of angle

    International Nuclear Information System (INIS)

    Tanner, J.E.; McDonald, J.C.; Stewart, R.D.; Wernli, C.

    1997-01-01

    The measured and calculated dose equivalent response as a function of angle has been examined for an albedo-type thermoluminescence dosemeter (TLD) that was exposed to unmoderated and D 2 O-moderated 252 Cf neutron sources while mounted on a 40 x 40 15 cm 3 polymethylmethacrylate phantom. The dosemeter used in this study is similar to many neutron personal dosemeters currently in use. The detailed construction of the dosemeter was modelled, and the dose equivalent response was calculated, using the MCNP code. Good agreement was found between the measured and calculated values of the relative dose equivalent angular response for the TLD albedo dosemeter. The relative dose equivalent angular response was also compared with the values of directional and personal dose equivalent as a function of angle published by Siebert and Schuhmacher. (author)

  9. Implementation of an Analytical Model for Leakage Neutron Equivalent Dose in a Proton Radiotherapy Planning System

    Directory of Open Access Journals (Sweden)

    John Eley

    2015-03-01

    Full Text Available Equivalent dose from neutrons produced during proton radiotherapy increases the predicted risk of radiogenic late effects. However, out-of-field neutron dose is not taken into account by commercial proton radiotherapy treatment planning systems. The purpose of this study was to demonstrate the feasibility of implementing an analytical model to calculate leakage neutron equivalent dose in a treatment planning system. Passive scattering proton treatment plans were created for a water phantom and for a patient. For both the phantom and patient, the neutron equivalent doses were small but non-negligible and extended far beyond the therapeutic field. The time required for neutron equivalent dose calculation was 1.6 times longer than that required for proton dose calculation, with a total calculation time of less than 1 h on one processor for both treatment plans. Our results demonstrate that it is feasible to predict neutron equivalent dose distributions using an analytical dose algorithm for individual patients with irregular surfaces and internal tissue heterogeneities. Eventually, personalized estimates of neutron equivalent dose to organs far from the treatment field may guide clinicians to create treatment plans that reduce the risk of late effects.

  10. Evaluation of dose equivalent rate distribution in JCO critical accident by radiation transport calculation

    CERN Document Server

    Sakamoto, Y

    2002-01-01

    In the prevention of nuclear disaster, there needs the information on the dose equivalent rate distribution inside and outside the site, and energy spectra. The three dimensional radiation transport calculation code is a useful tool for the site specific detailed analysis with the consideration of facility structures. It is important in the prediction of individual doses in the future countermeasure that the reliability of the evaluation methods of dose equivalent rate distribution and energy spectra by using of Monte Carlo radiation transport calculation code, and the factors which influence the dose equivalent rate distribution outside the site are confirmed. The reliability of radiation transport calculation code and the influence factors of dose equivalent rate distribution were examined through the analyses of critical accident at JCO's uranium processing plant occurred on September 30, 1999. The radiation transport calculations including the burn-up calculations were done by using of the structural info...

  11. Alternatives to dose, quality factor and dose equivalent for low level irradiation

    International Nuclear Information System (INIS)

    Sondhaus, C.A.; Bond, V.P.; Feinendegen, L.E.

    1988-01-01

    Randomly occurring energy deposition events produced by low levels of ionizing radiation interacting with tissue deliver variable amounts of energy to the sensitive target volumes within a small fraction of the cell population. A model is described in which an experimentally derived function relating event size to cell response probability operates mathematically on the microdosimetric event size distribution characterizing a given irradiation and thus determines the total fractional number of responding cells; this fraction measures the effectiveness of the given radiation. Normalizing to equal numbers of events produced by different radiations and applying this cell response or hit size effectiveness function (HSEF) should define radiation quality, or relative effectiveness, on a more nearly absolute basis than do the absorbed dose and dose evaluation, which are confounded when applied to low level irradiations. Examples using both calculation and experimental data are presented. 15 refs., 18 figs

  12. Variation of indoor radon concentration and ambient dose equivalent rate in different outdoor and indoor environments

    International Nuclear Information System (INIS)

    Stojanovska, Zdenka; Janevik, Emilija; Taleski, Vaso; Boev, Blazo; Zunic, Zora S.; Ivanova, Kremena; Tsenova, Martina; Ristova, Mimoza; Ajka, Sorsa; Bossew, Peter

    2016-01-01

    Subject of this study is an investigation of the variations of indoor radon concentration and ambient dose equivalent rate in outdoor and indoor environments of 40 dwellings, 31 elementary schools and five kindergartens. The buildings are located in three municipalities of two, geologically different, areas of the Republic of Macedonia. Indoor radon concentrations were measured by nuclear track detectors, deployed in the most occupied room of the building, between June 2013 and May 2014. During the deploying campaign, indoor and outdoor ambient dose equivalent rates were measured simultaneously at the same location. It appeared that the measured values varied from 22 to 990 Bq/m 3 for indoor radon concentrations, from 50 to 195 nSv/h for outdoor ambient dose equivalent rates, and from 38 to 184 nSv/h for indoor ambient dose equivalent rates. The geometric mean value of indoor to outdoor ambient dose equivalent rates was found to be 0.88, i.e. the outdoor ambient dose equivalent rates were on average higher than the indoor ambient dose equivalent rates. All measured can reasonably well be described by log-normal distributions. A detailed statistical analysis of factors which influence the measured quantities is reported. (orig.)

  13. Variation of indoor radon concentration and ambient dose equivalent rate in different outdoor and indoor environments

    Energy Technology Data Exchange (ETDEWEB)

    Stojanovska, Zdenka; Janevik, Emilija; Taleski, Vaso [Goce Delcev University, Faculty of Medical Sciences, Stip (Macedonia, The Former Yugoslav Republic of); Boev, Blazo [Goce Delcev University, Faculty of Natural and Technical Sciences, Stip (Macedonia, The Former Yugoslav Republic of); Zunic, Zora S. [University of Belgrade, Institute of Nuclear Sciences ' ' Vinca' ' , Belgrade (Serbia); Ivanova, Kremena; Tsenova, Martina [National Center of Radiobiology and Radiation Protection, Sofia (Bulgaria); Ristova, Mimoza [University in Ss. Cyril and Methodius, Faculty of Natural Sciences and Mathematic, Institute of Physics, Skopje (Macedonia, The Former Yugoslav Republic of); Ajka, Sorsa [Croatian Geological Survey, Zagreb (Croatia); Bossew, Peter [German Federal Office for Radiation Protection, Berlin (Germany)

    2016-05-15

    Subject of this study is an investigation of the variations of indoor radon concentration and ambient dose equivalent rate in outdoor and indoor environments of 40 dwellings, 31 elementary schools and five kindergartens. The buildings are located in three municipalities of two, geologically different, areas of the Republic of Macedonia. Indoor radon concentrations were measured by nuclear track detectors, deployed in the most occupied room of the building, between June 2013 and May 2014. During the deploying campaign, indoor and outdoor ambient dose equivalent rates were measured simultaneously at the same location. It appeared that the measured values varied from 22 to 990 Bq/m{sup 3} for indoor radon concentrations, from 50 to 195 nSv/h for outdoor ambient dose equivalent rates, and from 38 to 184 nSv/h for indoor ambient dose equivalent rates. The geometric mean value of indoor to outdoor ambient dose equivalent rates was found to be 0.88, i.e. the outdoor ambient dose equivalent rates were on average higher than the indoor ambient dose equivalent rates. All measured can reasonably well be described by log-normal distributions. A detailed statistical analysis of factors which influence the measured quantities is reported. (orig.)

  14. Equivalent dose, effective dose and risk assessment from panoramic radiography to the critical organs of head and neck region

    International Nuclear Information System (INIS)

    Cho, Bong Hae; Nah, Kyung Soo; Lee, Ae Ryeon

    1995-01-01

    The purpose of this study was to evaluate the equivalent and effective dose, and estimate radiation risk to the critical organs of head and neck region from the use of adult and child mode in panoramic radiography. The results were as follows. 1. The salivary glands showed the highest equivalent and effective dose in adult and child mode. The equivalent and effective dose in adult mode were 837 μSv and 20.93 μSv, those in child mode were 462 μSv and 11.54 μSv, respectively. 2. Total effective doses to the critical head and neck organs were estimated 34.2l μSv in adult mode, 20.14 μSv in child mode. From these data, the probabilities of stochastic effect from adult and child mode were 2.50xl0 -6 and 1.47x10 -6 3. The other remainder showed the greatest risk of fatal cancer. The risk estimate were 4.5 and 2.7 fatal malignancies in adult and child mode from million examinations. The bone marrow and thyroid gland showed about 0.1 fatal cancer in adult. and child mode from these examinations.

  15. Equivalent dose, effective dose and risk assessment from panoramic radiography to the critical organs of head and neck region

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Bong Hae; Nah, Kyung Soo [Dept. of Dental Radiology, College of Dentistry, Pusan National University, Pusan (Korea, Republic of); Lee, Ae Ryeon [Dept. of Pediatric Dentistry, College of Dentistry, Pusan National University, Pusan (Korea, Republic of)

    1995-08-15

    The purpose of this study was to evaluate the equivalent and effective dose, and estimate radiation risk to the critical organs of head and neck region from the use of adult and child mode in panoramic radiography. The results were as follows. 1. The salivary glands showed the highest equivalent and effective dose in adult and child mode. The equivalent and effective dose in adult mode were 837 {mu}Sv and 20.93 {mu}Sv, those in child mode were 462 {mu}Sv and 11.54 {mu}Sv, respectively. 2. Total effective doses to the critical head and neck organs were estimated 34.2l {mu}Sv in adult mode, 20.14 {mu}Sv in child mode. From these data, the probabilities of stochastic effect from adult and child mode were 2.50xl0{sup -6} and 1.47x10{sup -6} 3. The other remainder showed the greatest risk of fatal cancer. The risk estimate were 4.5 and 2.7 fatal malignancies in adult and child mode from million examinations. The bone marrow and thyroid gland showed about 0.1 fatal cancer in adult. and child mode from these examinations.

  16. Comparison of the pharmacokinetics of tacrolimus and cyclosporine at equivalent molecular doses

    DEFF Research Database (Denmark)

    Karamperis, N; Povlsen, J V; Højskov, Carsten Schriver

    2003-01-01

    study was to compare single-dose pk profiles of the two drugs, following oral and intravenous administration, on the basis of equivalent molecular dosing, thus ruling out the quantitative factor. Five healthy volunteers and 14 dialysis patients (7 hemodialysis, 7 peritoneal dialysis) were included...

  17. Calculation of Ambient (H*(10)) and Personal (Hp(10)) Dose Equivalent from a 252Cf Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Traub, Richard J.

    2010-03-26

    The purpose of this calculation is to calculate the neutron dose factors for the Sr-Cf-3000 neutron source that is located in the 318 low scatter room (LSR). The dose factors were based on the dose conversion factors published in ICRP-21 Appendix 6, and the Ambient dose equivalent (H*(10)) and Personal dose equivalent (Hp(10)) dose factors published in ICRP Publication 74.

  18. Annual dose equivalents estimation received by Cienfuegos population due medical practice

    International Nuclear Information System (INIS)

    Usagaua R, Z.; Santander I, E.

    1996-01-01

    This study represents the first evaluation of the effective equivalent dose that receives the population of the Cienfuegos province in Cuba because of medical practice. The evaluation is based on the tables of doses depending on several parameters that influence over these ones, and also based on large diagnostic examinations statistics of all medical institutions over a 9 years period. Values of examinations frequency, contribution to total dose from radiography, fluoroscopy, dental radiography and nuclear medicine, and other characteristics of the last ones are offered. A comparative reflection dealing with received doses by radiography and fluoroscopy techniques is also included. (authors). 4 refs

  19. Applicability of ambient dose equivalent H*(d) in mixed radiation fields - a critical discussion

    International Nuclear Information System (INIS)

    Hajek, M.; Vana, N.

    2004-01-01

    For purposes of routine radiation protection, it is desirable to characterize the potential irradiation of individuals in terms of a single dose equivalent quantity that would exist in a phantom approximating the human body. The phantom of choice is the ICRU sphere made of 30 cm diameter tissue-equivalent plastic with a density of 1 g.cm-3 and a mass composition of 76.2 % O, 11.1 % C, 10.1 % H and 2.6 % N. Ambient dose equivalent, H*(d), was defined in ICRU report 51 as the dose equivalent that would be produced by an expanded and aligned radiation field at a depth d in the ICRU sphere. The recommended reference depths are 10 mm for strongly penetrating radiation and 0.07 mm for weakly penetrating radiation, respectively. As an operational quantity in radiation protection, H*(d) shall serve as a conservative and directly measurable estimate of protection quantities, e.g. effective dose E, which in turn are intended to give an indication of the risk associated with radiation exposure. The situation attains increased complexity in radiation environments being composed of a variety of charged and uncharged particles in a broad energetic spectrum. Radiation fields of similarly complex nature are, for example, encountered onboard aircraft and in space. Dose equivalent was assessed as a function of depth in quasi tissue-equivalent spheres by means of thermoluminescent dosemeters evaluated according to the high-temperature ratio (HTR) method. The presented experiments were performed both onboard aircraft and the Russian space station Mir. As a result of interaction processes within the phantom body, the incident primary spectrum may be significantly modified with increasing depth. For the radiation field at aviation altitudes we found the maximum of dose equivalent in a depth of 60 mm which conflicts with the 10 mm value recommended by ICRU. Contrary, for the space radiation environment the maximum dose equivalent was found at the surface of the sphere. This suggests that

  20. Applicability of Ambient Dose Equivalent H (d) in Mixed Radiation Fields - A Critical Discussion

    International Nuclear Information System (INIS)

    Vana, R.; Hajek, M.; Bergerm, T.

    2004-01-01

    For purposes of routine radiation protection, it is desirable to characterize the potential irradiation of individuals in terms of a single dose equivalent quantity that would exist in a phantom approximating the human body. The phantom of choice is the ICRU sphere made of 30 cm diameter tissue-equivalent plastic with a density of 1 g/cm3 and a mass composition of 76.2% O, 11.1% C, 10.1% H and 2.6% N. Ambient dose equivalent, H(d), was defined in ICRU report 51 as the dose equivalent that would be produced by an expanded and aligned radiation field at a depth d in the ICRU sphere. The recommended reference depths are 10 mm for strongly penetrating radiation and 0.07 mm for weakly penetrating radiation, respectively. As an operational quantity in radiation protection, H(d) shall serve as a conservative and directly measurable estimate of protection quantities, e.g. effective dose E, which in turn are intended to give an indication of the risk associated with radiation exposure. The situation attains increased complexity in radiation environments being composed of a variety of charged and uncharged particles in a broad energetic spectrum. Radiation fields of similarly complex nature are, for example, encountered onboard aircraft and in space. Dose equivalent was assessed as a function of depth in quasi tissue-equivalent spheres by means of thermoluminescent dosemeters evaluated according to the high-temperature ratio (HTR) method. The presented experiments were performed both onboard aircraft and the Russian space station Mir. As a result of interaction processes within the phantom body, the incident primary spectrum may be significantly modified with increasing depth. For the radiation field at aviation altitudes we found the maximum of dose equivalent in a depth of 60 mm which conflicts with the 10 mm value recommended by ICRU. Contrary, for the space radiation environment the maximum dose equivalent was found at the surface of the sphere. This suggests that skin

  1. Metoprolol Dose Equivalence in Adult Men and Women Based on Gender Differences: Pharmacokinetic Modeling and Simulations

    Directory of Open Access Journals (Sweden)

    Andy R. Eugene

    2016-11-01

    Full Text Available Recent meta-analyses and publications over the past 15 years have provided evidence showing there are considerable gender differences in the pharmacokinetics of metoprolol. Throughout this time, there have not been any research articles proposing a gender stratified dose-adjustment resulting in an equivalent total drug exposure. Metoprolol pharmacokinetic data was obtained from a previous publication. Data was modeled using nonlinear mixed effect modeling using the MONOLIX software package to quantify metoprolol concentration–time data. Gender-stratified dosing simulations were conducted to identify equivalent total drug exposure based on a 100 mg dose in adults. Based on the pharmacokinetic modeling and simulations, a 50 mg dose in adult women provides an approximately similar metoprolol drug exposure to a 100 mg dose in adult men.

  2. Dose equivalent measurements in mixed and time varying radiation fields around high-energy accelerators

    CERN Document Server

    Mayer, S

    2003-01-01

    Measurements of ambient dose equivalent in stray radiation fields behind the shielding of high-energy accelerators are a challenging task. Several radiation components (photons, neutrons, charged particles, muons, etc.), spanning a wide range of energies, contribute to the total dose equivalent. The radiation fields are produced by beam losses interacting with structural material during the acceleration or at the ejection to experimental areas or other accelerators. The particle beam is usually not continuous but separated in "bunches" or pulses, which further complicates dose measurements at high-energy accelerators. An ideal dosimeter for operational radiation protection should measure dose equivalent for any composition of radiation components in the entire energy range even when the field is strongly pulsed. The objective of this work was to find out if an ionisation chamber operated as a "recombination chamber" and a TEPC instrument using the variance-covariance method ("Sievert Instrument") are capable ...

  3. Benefits of the effective dose equivalent concept at a medical center

    International Nuclear Information System (INIS)

    Vetter, R.J.; Classic, K.L.

    1991-01-01

    A primary objective of the recommendations of the International Committee on Radiological Protection Publication 26 is to insure that no source of radiation exposure is unjustified in relation to its benefits. This objective is consistent with goals of the Radiation Safety Committee and Institutional Review Board at medical centers where research may involve radiation exposure of human subjects. The effective dose equivalent concept facilitates evaluation of risk by those who have little or no knowledge of quantities or biological effects of radiation. This paper presents effective dose equivalent data used by radiation workers and those who evaluate human research protocols as these data relate to personal dosimeter reading, entrance skin exposure, and target organ dose. The benefits of using effective dose equivalent to evaluate risk of medical radiation environments and research protocols are also described

  4. Equivalence in Dose Fall-Off for Isocentric and Nonisocentric Intracranial Treatment Modalities and Its Impact on Dose Fractionation Schemes

    International Nuclear Information System (INIS)

    Ma Lijun; Sahgal, Arjun; Descovich, Martina; Cho, Y.-B.; Chuang, Cynthia; Huang, Kim; Laperriere, Normand J.; Shrieve, Dennis C.; Larson, David A.

    2010-01-01

    Purpose: To investigate whether dose fall-off characteristics would be significantly different among intracranial radiosurgery modalities and the influence of these characteristics on fractionation schemes in terms of normal tissue sparing. Methods and Materials: An analytic model was developed to measure dose fall-off characteristics near the target independent of treatment modalities. Variations in the peripheral dose fall-off characteristics were then examined and compared for intracranial tumors treated with Gamma Knife, Cyberknife, or Novalis LINAC-based system. Equivalent uniform biologic effective dose (EUBED) for the normal brain tissue was calculated. Functional dependence of the normal brain EUBED on varying numbers of fractions (1 to 30) was studied for the three modalities. Results: The derived model fitted remarkably well for all the cases (R 2 > 0.99). No statistically significant differences in the dose fall-off relationships were found between the three modalities. Based on the extent of variations in the dose fall-off curves, normal brain EUBED was found to decrease with increasing number of fractions for the targets, with α/β ranging from 10 to 20. This decrease was most pronounced for hypofractionated treatments with fewer than 10 fractions. Additionally, EUBED was found to increase slightly with increasing number of fractions for targets with α/β ranging from 2 to 5. Conclusion: Nearly identical dose fall-off characteristics were found for the Gamma Knife, Cyberknife, and Novalis systems. Based on EUBED calculations, normal brain sparing was found to favor hypofractionated treatments for fast-growing tumors with α/β ranging from 10 to 20 and single fraction treatment for abnormal tissues with low α/β values such as α/β = 2.

  5. Biological equivalence of low dose rate to multifractionated high dose rate irradiations: investigations in mouse lip mucosa

    International Nuclear Information System (INIS)

    Stueben, Georg; Kogel, Albert J. van der; Schueren, Emmanuel van der

    1997-01-01

    Background and purpose: The aim of this study was to evaluate the biological equivalence of continuous low dose rate (LDR) irradiations to multifractionated high dose rate (HDR) regimes. The applicability of the LQ model was analysed for fraction sizes and dose rates relevant for the clinic. Material and methods: Investigations were performed in mouse lip mucosa. HDR fractions were given in an overall treatment time ranging from 10 h to 3.5 days. The dose rate effect was analysed in the range of 84 to 0.76 Gy/h. For an assessment of biological equivalence in comparison to LDR, HDR irradiations have been performed in the same overall treatment time as the corresponding LDR regimes. Results: Recovery leads to sparing of radiation damage as the dose rate is reduced from 84 to 0.76 Gy/h (20.0 versus 45.7 Gy ED 50 ). No significant additional sparing from 0.9 to 0.76 Gy/h could be demonstrated (44.9 versus 45.7 Gy ED 50 ). Even 30 HDR fractions in 24 h were not sufficient to match the effect of LDR over the same time period (38.2 versus 41.1 Gy ED 50 ). The present data give evidence for a bi-exponential repair process in mouse lip mucosa (T 1/2fast 27 min, T 1/2slow 150 min). Repair is dominated by the faster component (>80%). Conclusions: LDR is the most efficient way to deliver radiation if recovery is to be maximised and the overall time kept as short as possible. When used with realistic parameters the LQ model is capable of providing quantitative guidelines in areas of clinical interest

  6. Quantifying the Combined Effect of Radiation Therapy and Hyperthermia in Terms of Equivalent Dose Distributions

    International Nuclear Information System (INIS)

    Kok, H. Petra; Crezee, Johannes; Franken, Nicolaas A.P.; Stalpers, Lukas J.A.; Barendsen, Gerrit W.; Bel, Arjan

    2014-01-01

    Purpose: To develop a method to quantify the therapeutic effect of radiosensitization by hyperthermia; to this end, a numerical method was proposed to convert radiation therapy dose distributions with hyperthermia to equivalent dose distributions without hyperthermia. Methods and Materials: Clinical intensity modulated radiation therapy plans were created for 15 prostate cancer cases. To simulate a clinically relevant heterogeneous temperature distribution, hyperthermia treatment planning was performed for heating with the AMC-8 system. The temperature-dependent parameters α (Gy −1 ) and β (Gy −2 ) of the linear–quadratic model for prostate cancer were estimated from the literature. No thermal enhancement was assumed for normal tissue. The intensity modulated radiation therapy plans and temperature distributions were exported to our in-house-developed radiation therapy treatment planning system, APlan, and equivalent dose distributions without hyperthermia were calculated voxel by voxel using the linear–quadratic model. Results: The planned average tumor temperatures T90, T50, and T10 in the planning target volume were 40.5°C, 41.6°C, and 42.4°C, respectively. The planned minimum, mean, and maximum radiation therapy doses were 62.9 Gy, 76.0 Gy, and 81.0 Gy, respectively. Adding hyperthermia yielded an equivalent dose distribution with an extended 95% isodose level. The equivalent minimum, mean, and maximum doses reflecting the radiosensitization by hyperthermia were 70.3 Gy, 86.3 Gy, and 93.6 Gy, respectively, for a linear increase of α with temperature. This can be considered similar to a dose escalation with a substantial increase in tumor control probability for high-risk prostate carcinoma. Conclusion: A model to quantify the effect of combined radiation therapy and hyperthermia in terms of equivalent dose distributions was presented. This model is particularly instructive to estimate the potential effects of interaction from different treatment

  7. Evaluation of personal dose equivalent using optically stimulated luminescent dosemeters in Marumori after the Fukushima nuclear accident

    International Nuclear Information System (INIS)

    Yoshida-Ohuchi, H.; Hirasawa, N.; Kobayashi, I.; Yoshizawa, T.

    2013-01-01

    The personal dose equivalent for 36 Marumori residents living in wooden houses was evaluated using optically stimulated luminescent dosemeters after the Fukushima nuclear accident. The cumulative doses to residents over 200 d from 1 September 2011 ranged from 536 to 1490 μSv. In each resident's house, the indoor and outdoor ambient dose equivalents were measured with an NaI scintillation survey meter. A linear relationship with a slope of 0.5 was found between them; however, the ratio of the indoor to the outdoor ambient dose equivalent varied from 0.36 to 1.0. A better linear relationship was observed between the personal dose equivalent and the indoor ambient dose equivalent compared with that between the personal dose equivalent and the outdoor ambient dose equivalent. These results indicate that the individual exposure dose depends on the indoor ambient dose equivalent rather than the outdoor ambient dose equivalent. These results should be very helpful in obtaining the countermeasures to reduce residents' exposure dose. (authors)

  8. Neutron equivalent doses and associated lifetime cancer incidence risks for head & neck and spinal proton therapy

    Science.gov (United States)

    Athar, Basit S.; Paganetti, Harald

    2009-08-01

    In this work we have simulated the absorbed equivalent doses to various organs distant to the field edge assuming proton therapy treatments of brain or spine lesions. We have used computational whole-body (gender-specific and age-dependent) voxel phantoms and considered six treatment fields with varying treatment volumes and depths. The maximum neutron equivalent dose to organs near the field edge was found to be approximately 8 mSv Gy-1. We were able to clearly demonstrate that organ-specific neutron equivalent doses are age (stature) dependent. For example, assuming an 8-year-old patient, the dose to brain from the spinal fields ranged from 0.04 to 0.10 mSv Gy-1, whereas the dose to the brain assuming a 9-month-old patient ranged from 0.5 to 1.0 mSv Gy-1. Further, as the field aperture opening increases, the secondary neutron equivalent dose caused by the treatment head decreases, while the secondary neutron equivalent dose caused by the patient itself increases. To interpret the dosimetric data, we analyzed second cancer incidence risks for various organs as a function of patient age and field size based on two risk models. The results show that, for example, in an 8-year-old female patient treated with a spinal proton therapy field, breasts, lungs and rectum have the highest radiation-induced lifetime cancer incidence risks. These are estimated to be 0.71%, 1.05% and 0.60%, respectively. For an 11-year-old male patient treated with a spinal field, bronchi and rectum show the highest risks of 0.32% and 0.43%, respectively. Risks for male and female patients increase as their age at treatment time decreases.

  9. Effective dose equivalent to the operator in intra-oral dental radiography

    Energy Technology Data Exchange (ETDEWEB)

    de Haan, R.A.; van Aken, J. (Utrecht Univ., (The Netherlands))

    1990-08-01

    The effective dose equivalent to the operator in intra-oral dental radiography has been determined. The exposure from a bitewing radiograph and periapical views of the left maxillary incisors and first molar was measured at nine heights and 16 positions, all 1 m from the patient. The effective dose equivalent was determined using data from ICRP 51 (International Commission on Radiological Protection: Data for Use in Protection Against External Radiation). The values presented are related to an exposure of 1 C kg-1 (3876 R) measured free in air at the tube-end. They thus constitute ratios which are not influenced by the sensitivity of the film or other detector used and form standard tables which permit the calculation of the effective dose equivalent in clinical situations.

  10. Effective dose equivalent to the operator in intra-oral dental radiography

    International Nuclear Information System (INIS)

    de Haan, R.A.; van Aken, J.

    1990-01-01

    The effective dose equivalent to the operator in intra-oral dental radiography has been determined. The exposure from a bitewing radiograph and periapical views of the left maxillary incisors and first molar was measured at nine heights and 16 positions, all 1 m from the patient. The effective dose equivalent was determined using data from ICRP 51 (International Commission on Radiological Protection: Data for Use in Protection Against External Radiation). The values presented are related to an exposure of 1 C kg-1 (3876 R) measured free in air at the tube-end. They thus constitute ratios which are not influenced by the sensitivity of the film or other detector used and form standard tables which permit the calculation of the effective dose equivalent in clinical situations

  11. Calculation of the dose equivalent around a patient receiving treatment with {sup 125}I seeds

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Toru; Dokiya, Takushi; Toya, Kazuhito; Kawase, Takatsugu [National Tokyo Medical Center Hospital (Japan); Hashimoto, Mitsuyasu

    2001-03-01

    Interstitial brachytherapy with {sup 125}I seeds for treatment of prostate cancer is being carried out successfully in Europe and U.S.A. However, its widespread use in Japan has been limited by regulations governing the exposure of individuals. Basic radiation protection data are required to promote the use of {sup 125}I seed sources. In preparation for implementing this new modality, we carried out a series of measurements to determine the 1 cm dose equivalent in a caregiver located 1 m from the implanted patient. These measurements were compared with published recommendations of acceptable doses, and may be used to develop guidelines for discharge of the patient. The 1 cm dose equivalent was measured 1 m from the source under clinically relevant conditions by placing 50 {sup 125}I seeds (437.5 MBq) into the portion of a humanoid phantom that corresponds to the prostate. The 1 cm dose equivalent was 0.0014 {mu}Sv{center_dot}m{sup 2}{center_dot}MBq{sup -1}{center_dot}h{sup -1} 1 m from the surface of the phantom. The calculated dose to a caregiver based on this figure is well below the 5 mSv value recommended by the IAEA as a constraint dose for the caregiver. These measurements and calculations suggest that {sup 125}I seed implants of outpatients should be permissible. (author)

  12. Equivalent dose estimation using a single aliquot of polymineral fine grains

    DEFF Research Database (Denmark)

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

    2001-01-01

    We have tested the suitability of a new single-aliquot regenerative-dose protocol for estimating the equivalent dose (D-e) in polymineral fine grains extracted from colluvia from various sites in Germany. First, we report the behaviour of three OSL signals: (i) blue-stimulated, (ii) infrared......C, the post-IR blue signals are stable. The preheat dependence of estimates of D-e obtained using fine grains is presented for the first time, for both blue- and IR-derived signals. Our results are compared with D-e estimates derived from multiple-aliquot additive-dose IR luminescence data, obtained using...

  13. Estimates of effective equivalent dose commitments for Slovene population following the Chernobyl accident

    International Nuclear Information System (INIS)

    Kanduc, M.; Jovanowic, O.; Kuhar, B.

    2004-01-01

    This paper shows the estimates of effective equivalent dose commitments for the two groups of Slovene population, 5 years old children and adults. Doses were calculated on the basis of the ICRP 30 methodology, first from the measurements of the concentrations of the radionuclides in air, water and food samples and then compared with the results of the measurements of radionuclides in composite samples of the prepared food, taken in the kindergarten nearby. Results show that there is certain degree of conservatism hidden in the calculation of the doses on the basis of measurements of the activity concentration in the elements of the biosphere and is estimated to be roughly 50%. (author)

  14. Personal dose equivalent conversion coefficients for electrons to 1 Ge V.

    Science.gov (United States)

    Veinot, K G; Hertel, N E

    2012-04-01

    In a previous paper, conversion coefficients for the personal dose equivalent, H(p)(d), for photons were reported. This note reports values for electrons calculated using similar techniques. The personal dose equivalent is the quantity used to approximate the protection quantity effective dose when performing personal dosemeter calibrations and in practice the personal dose equivalent is determined using a 30×30×15 cm slab-type phantom. Conversion coefficients to 1 GeV have been calculated for H(p)(10), H(p)(3) and H(p)(0.07) in the recommended slab phantom. Although the conversion coefficients were determined for discrete incident energies, analytical fits of the conversion coefficients over the energy range are provided using a similar formulation as in the photon results previously reported. The conversion coefficients for the personal dose equivalent are compared with the appropriate protection quantity, calculated according to the recommendations of the latest International Commission on Radiological Protection guidance. Effects of eyewear on H(p)(3) are also discussed.

  15. Developing a single-aliquot protocol for measuring equivalent dose in biogenic carbonates

    International Nuclear Information System (INIS)

    Stirling, R.J.; Duller, G.A.T.; Roberts, H.M.

    2012-01-01

    Exploiting biogenic carbonates as thermoluminescence dosimeters requires an understanding of trap kinetics and an appropriate sequence with which to measure equivalent dose. The trap kinetics of two high temperature peaks (peaks II and III) from calcitic snail opercula have been investigated resulting in the calculation of lifetimes of 7.4 × 10 7 and 1.4 × 10 11 years for the two peaks respectively. Two measurement sequences, based upon changes in the application and measurement of a test dose, have been applied to peaks II and III, and though both methods were equally successful in dose recovery and production of a dose response curve some differences were observed. Primarily, the use of method 1 lead to dose dependant sensitivity change implying competition effects occurring during irradiation; method 2 did not experience this phenomenon. As a consequence method 2 was chosen as the most appropriate protocol for single-aliquot dating of this material. When assessing the TL behaviour of the two peaks, peak II performed poorly in dose recovery experiments recovering a dose 60–100% larger than that applied. Disproportionate growth of peak II in response to a beta dose applied prior to measurement, compared to growth following regeneration doses indicated that peak II was not suitable for use in single-aliquot protocols. However, dose recovery results for peak III were all within errors of unity of the given dose, and peak III was therefore chosen as the most appropriate peak for TL dosimetry in these single-aliquot procedures. The lifetime of charge in peak III is sufficient to date over many millions of years, and furthermore using the chosen method 2 the dose response curve has a D 0 of 3,250 ± 163 Gy allowing dating to over 3 million years.

  16. Neutron fluence-to-dose equivalent conversion factors: a comparison of data sets and interpolation methods

    International Nuclear Information System (INIS)

    Sims, C.S.; Killough, G.G.

    1983-01-01

    Various segments of the health physics community advocate the use of different sets of neutron fluence-to-dose equivalent conversion factors as a function of energy and different methods of interpolation between discrete points in those data sets. The major data sets and interpolation methods are used to calculate the spectrum average fluence-to-dose equivalent conversion factors for five spectra associated with the various shielded conditions of the Health Physics Research Reactor. The results obtained by use of the different data sets and interpolation methods are compared and discussed. (author)

  17. Evaluation of the equivalent dose rates due to neutrons emitted by plutonium oxide sources. Graphs

    International Nuclear Information System (INIS)

    Gouguet, Jackie.

    1975-06-01

    In irradiated fuel processing plants, the personnel concerned with radioprotection often require a rapid estimation of the equivalent dose rates due to neutrons emitted by plutonium oxide sources, sources having different physical and geometrical characteristics. Graphs are presented which facilitate rapid determinations. Graphs enabling the equivalent dose rates to be evaluated in contact with or at some distance from plutonium oxide sources of different geometrical characteristics are presented, the plutonium being obtained from fuels having been irradiated at different burn up in light water power reactors [fr

  18. Determination of the equivalent of environmental dose, H*(d), in a radiotherapy installation; Determinacao do equivalente de dose ambiental, H*(d), em uma instalacao de radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Lima, M.A.F.; Borges, J.C. [Universidade Federal de Rio de Janeiro, PEN/COPPE/UFRJ Caixa Postal 68509 21945-970, Rio de Janeiro (Brazil); Mota, H.C. [Instituto de Radio Protecao e Dosimetria, IRD/CNEN Caixa Postal 37750 22780-160, Rio de Janeiro (Brazil)

    1998-12-31

    In order to put into practice radiological protection has been required conversion factors for environmental dose equivalent determination to air kerma value for different kinds of photon and electron beams, such dose values have been determined in a spheric phantom of 30 cm diameter in a alignment field and expanded in a depth of this sphere. Details will be given for determining of equivalent dose distribution calculation using Monte Carlo computational method (ESG4) following the recommendations of ICRU. (Author)

  19. Bioequivalence of a fixed-dose repaglinide/metformin combination tablet and equivalent doses of repaglinide and metformin tablets
.

    Science.gov (United States)

    Cho, Hea-Young; Ngo, Lien; Kim, Sang-Ki; Choi, Yoonho; Lee, Yong-Bok

    2018-04-12

    This study was conducted to determine whether a fixed-dose combination (FDC) tablet of repaglinide/metformin (2/500 mg) is equivalent to coadministration of equivalent doses of individual (EDI) tablets of repaglinide (2 mg) and metformin (500 mg) in healthy Korean male subjects. This study was conducted as an open-label, randomized, single-dose, two-period, two-sequence crossover design in 50 healthy Korean male subjects who received an FDC tablet or EDI tablets. Plasma concentrations of repaglinide and metformin were determined for up to 24 hours using a validated UPLC-MS/MS method. Bioequivalence was assessed according to current guidelines issued by the U.S. Food and Drug Administration (FDA) and Korean legislation. Tolerability was also evaluated throughout the study via subject interview, vital signs, and blood sampling. Point estimates (90% CIs) for AUC0-t, AUC0-∞, and Cmax based on EDI tablets were 110.07 (102.25 - 118.49), 109.90 (101.70 - 118.39), and 112.60 (101.49 - 124.85), respectively, for repaglinide. They were 95.18 (89.62 - 101.05), 95.00 (89.74 - 100.65), and 98.44 (92.72 - 104.50), respectively, for metformin. These results satisfied the bioequivalence criteria of 80.00 - 125.00% proposed by the FDA and Korean legislation. Results of pharmacokinetic analysis suggested that repaglinide and metformin in FDC tablets were bioequivalent to EDI tablets of repaglinide (2 mg) and metformin (500 mg) in healthy Korean male subjects. Both formulations appeared to be well tolerated.
.

  20. Dose of radiation enhancement, using silver nanoparticles in a human tissue equivalent gel dosimeter.

    Science.gov (United States)

    Hassan, Muhammad; Waheed, Muhammad Mohsin; Anjum, Muhammad Naeem

    2016-01-01

    To quantify the radiation dose enhancement in a human tissue-equivalent polymer gel impregnated with silver nanoparticles. The case-control study was conducted at the Bahawalpur Institute of Nuclear Medicine and Oncology, Bahawalpur, Pakistan, in January 2014. Silver nanoparticles used in this study were prepared by wet chemical method. Polymer gel was prepared by known quantity of gelatine, methacrylic acid, ascorbic acid, copper sulphate pentahydrate, hydroquinone and water. Different concentrations of silver nanoparticles were added to the gel during its cooling process. The gel was cooled in six plastic vials of 50ml each. Two vials were used as a control sample while four vials were impregnated with silver nanoparticles. After 22 hours, the vials were irradiated with gamma rays by aCobalt-60 unit. Radiation enhancement was assessed by taking magnetic resonance images of the vials. The images were analysed using Image J software. The dose enhancement factor was 24.17% and 40.49% for 5Gy and 10Gy dose respectively. The dose enhancement factor for the gel impregnated with 0.10mM silver nanoparticles was 32.88% and 51.98% for 5Gy and 10Gy dose respectively. The impregnation of a tissue-equivalent gel with silver nanoparticles resulted in dose enhancement and this effect was magnified up to a certain level with the increase in concentration of silver nanoparticles.

  1. Additional effective dose equivalent for adults and children in Poland as the result of mushroom consumption

    International Nuclear Information System (INIS)

    Jasinska, H.; Kozak, K.; Mietelski, J.W.

    2004-01-01

    Experimental data of caesium radioactivity in samples of various mushrooms collected all over Poland from 1986 to 1989 are presented. Nearly 80 samples from Poland and a few samples from Austria and USSR were analysed. The effective dose equivalents for adults and children caused by the consumption of one mass unit of dried mushrooms for each sample were estimated. (author)

  2. Evaluation of the effective dose equivalent to tbe public of Pavia after the Chernobyl nuclear accident

    International Nuclear Information System (INIS)

    Altieri, S.; Berzero, A.; Meloni, S.; Rosti, G.; Genova, N.

    1988-01-01

    The Chernobyl radionuclide monitoring campaign in air particulate and foodstuffs was carried out and continued up to June 1987. On the basis of collected data estimates of the collective effective dose equivalent commitment to the public of province of Pavia, by external irradiation or by inhalation, were carried out and are reported in the present paper

  3. Dependence on age at intake of committed dose equivalents from radionuclides

    International Nuclear Information System (INIS)

    Adams, N.

    1981-01-01

    The dependence of committed dose equivalents on age at intake is needed to assess the significance of exposures of young persons among the general public resulting from inhaled or ingested radionuclides. The committed dose equivalents, evaluated using ICRP principles, depend on the body dimensions of the young person at the time of intake of a radionuclide and on subsequent body growth. Representation of growth by a series of exponential segments facilitates the derivation of general expressions for the age dependence of committed dose equivalents if metabolic models do not change with age. The additional assumption that intakes of radionuclides in air or food are proportional to a person's energy expenditure (implying age-independent dietary composition) enables the demonstration that the age of the most highly exposed 'critical groups' of the general public from these radionuclides is either about 1 year or 17 years. With the above assumptions the exposure of the critical group is less than three times the exposure of adult members of the general public. Approximate values of committed dose equivalents which avoid both underestimation and excessive overestimation are shown to be obtainable by simplified procedures. Modified procedures are suggested for use if metabolic models change with age. (author)

  4. Proposed dose equivalence between clonazepam and pramipexole in patients with restless legs syndrome.

    Science.gov (United States)

    Shinno, Hideto; Oka, Yasunori; Otsuki, Manabu; Tsuchiya, Satoshi; Mizuno, Soichi; Kawada, Seiichi; Innami, Toshihiko; Sasaki, Akira; Hineno, Takashi; Sakamoto, Tetsuro; Inami, Yasushi; Nakamura, Yu; Horiguchi, Jun

    2010-04-16

    Dopamine agonists are accepted as the first-line medications for restless legs syndrome (RLS). In some Asian countries, clonazepam is one of the prevalent medications for RLS because of its effect on sleep disturbances. To date, there have not been any studies that examined equivalent doses of pramipexole and clonazepam. To evaluate equivalent doses of pramipexole and clonazepam in RLS, we investigated the efficacy and tolerability after conversion from clonazepam to pramipexole, and examined dose equivalence between the two prescriptions. In a prospective, open-label, multicenter study, 26 RLS patients treated with clonazepam (mean age: 69.2+/-11.0years old) were enrolled and then rapidly switched to pramipexole using a conversion calculation of 4:1 for daily doses. Then the daily dose of pramipexole was up titrated or tapered by 0.125mg/day at each subsequent examination. RLS symptoms and daytime somnolence were evaluated using the International RLS Study Group rating scale (IRLS), Clinical Global Impressions - Severity of illness (CGI-S) and the Epworth Sleepiness Scale (ESS), respectively. Conversion from clonazepam to pramipexole resulted in significant reductions of IRLS (16.3+/-8.7 to 9.1+/-6.3) and ESS (6.5+/-4.2 to 4.4+/-3.2). CGI scores demonstrated improvement after conversion. In 4 patients (15%), adverse events such as somnolence, sensation of oppression in the lower limbs, diarrhea, or nausea were present. Correlation analysis demonstrated a significant relationship between these daily doses. Spearman's correlation coefficient was 0.662. Our study, however, has some limitations since it is an open-label trial and includes only 26 patients. Further studies using a double-blind design or a crossover design are recommended. Statistical analysis demonstrated a 4:1 conversion for clonazepam to pramipexole. When switchover from clonazepam to pramipexole is done, this conversion ratio may be helpful to determine the initial dose of pramipexole for treating

  5. Ambient neutron dose equivalent outside concrete vault rooms for 15 and 18 MV radiotherapy accelerators

    International Nuclear Information System (INIS)

    Martinez-ovalle, S. A.; Barquero, R.; Gomez-ros, J. M.; Lallena, A. M.

    2012-01-01

    In this work, the ambient dose equivalent, H*(10), due to neutrons outside three bunkers that house a 15- and a 18-MV Varian Clinac 2100C/D and a 15-MV Elekta Inor clinical linacs, has been calculated. The Monte Carlo code MCNPX (v. 2.5) has been used to simulate the neutron production and transport. The complete geometries including linacs and full installations have been built up according to the specifications of the manufacturers and the planes provided by the corresponding medical physical services of the hospitals where the three linacs operate. Two of these installations, those lodging the Varian linacs, have an entrance door to the bunker while the other one does not, although it has a maze with two bends. Various treatment orientations were simulated in order to establish plausible annual equivalent doses. Specifically anterior-posterior, posterior-anterior, left lateral, right lateral orientations and an additional one with the gantry rotated 30 deg. have been studied. Significant dose rates have been found only behind the walls and the door of the bunker, near the entrance and the console, with a maximum of 12 μSv h -1 . Dose rates per year have been calculated assuming a conservative workload for the three facilities. The higher dose rates in the corresponding control areas were 799 μSv y -1 , in the case of the facility which operates the 15-MV Clinac, 159 μSv y -1 , for that with the 15-MV Elekta, and 21 μSv y -1 for the facility housing the 18-MV Varian. A comparison with measurements performed in similar installations has been carried out and a reasonable agreement has been found. The results obtained indicate that the neutron contamination does not increase the doses above the legal limits and does not produce a significant enhancement of the dose equivalent calculated. When doses are below the detection limits provided by the measuring devices available today, MCNPX simulation provides an useful method to evaluate neutron dose equivalents

  6. Eye lens dose correlations with personal dose equivalent and patient exposure in paediatric interventional cardiology performed with a fluoroscopic biplane system.

    Science.gov (United States)

    Alejo, L; Koren, C; Corredoira, E; Sánchez, F; Bayón, J; Serrada, A; Guibelalde, E

    2017-04-01

    To analyse the correlations between the eye lens dose estimates performed with dosimeters placed next to the eyes of paediatric interventional cardiologists working with a biplane system, the personal dose equivalent measured on the thorax and the patient dose. The eye lens dose was estimated in terms of H p (0.07) on a monthly basis, placing optically stimulated luminescence dosimeters (OSLDs) on goggles. The H p (0.07) personal dose equivalent was measured over aprons with whole-body OSLDs. Data on patient dose as recorded by the kerma-area product (P KA ) were collected using an automatic dose management system. The 2 paediatric cardiologists working in the facility were involved in the study, and 222 interventions in a 1-year period were evaluated. The ceiling-suspended screen was often disregarded during interventions. The annual eye lens doses estimated on goggles were 4.13±0.93 and 4.98±1.28mSv. Over the aprons, the doses obtained were 10.83±0.99 and 11.97±1.44mSv. The correlation between the goggles and the apron dose was R 2 =0.89, with a ratio of 0.38. The correlation with the patient dose was R 2 =0.40, with a ratio of 1.79μSvGy -1 cm -2 . The dose per procedure obtained over the aprons was 102±16μSv, and on goggles 40±9μSv. The eye lens dose normalized to P KA was 2.21±0.58μSvGy -1 cm -2 . Measurements of personal dose equivalent over the paediatric cardiologist's apron are useful to estimate eye lens dose levels if no radiation protection devices are typically used. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  7. The meaning and the principle of determination of the effective dose equivalent in radiation protection

    International Nuclear Information System (INIS)

    Drexler, G.; Williams, G.; Zankl, M.

    1985-01-01

    Since the introduction of the quantity ''effective dose equivalent'' within the framework of new radiation concepts, the meaning and interpretation of the quantity is often discussed and debated. Because of its adoption as a limiting quantity in many international and national laws, it is necessary to be able to interpret this main radiation protection quantity. Examples of organ doses and the related Hsub(E) values in occupational and medical exposures are presented and the meaning of the quantity is considered for whole body exposures to external and internal photon sources, as well as for partial body external exposures to photons. (author)

  8. Dose equivalents of antidepressants: Evidence-based recommendations from randomized controlled trials.

    Science.gov (United States)

    Hayasaka, Yu; Purgato, Marianna; Magni, Laura R; Ogawa, Yusuke; Takeshima, Nozomi; Cipriani, Andrea; Barbui, Corrado; Leucht, Stefan; Furukawa, Toshi A

    2015-07-15

    Dose equivalence of antidepressants is critically important for clinical practice and for research. There are several methods to define and calculate dose equivalence but for antidepressants, only daily defined dose and consensus methods have been applied to date. The purpose of the present study is to examine dose equivalence of antidepressants by a less arbitrary and more systematic method. We used data from all randomized, double-blind, flexible-dose trials comparing fluoxetine or paroxetine as standard drugs with any other active antidepressants as monotherapy in the acute phase treatment of unipolar depression. We calculated the ratio of the mean doses for each study and weighted it by the total sample size to find the weighted mean ratio for each drug, which was then used to define the drug׳s dosage equivalent to fluoxetine 40mg/d. We included 83 studies (14 131 participants). In the primary analysis, fluoxetine 40mg/day was equivalent to paroxetine dosage of 34.0mg/day, agomelatine 53.2mg/day, amitriptyline, 122.3mg/day, bupropion 348.5mg/day, clomipramine 116.1mg/day, desipramine 196.3mg/day, dothiepin 154.8mg/day, doxepin 140.1mg/day, escitalopram 18.0mg/day, fluvoxamine 143.3mg/day, imipramine 137.2mg/day, lofepramine 250.2mg/day, maprotiline 118.0mg/day, mianserin, 101.1mg/day, mirtazapine 50.9mg/day, moclobemide 575.2mg/day, nefazodone 535.2mg/day, nortriptyline 100.9mg/day, reboxetine 11.5mg/day, sertraline 98.5mg/day, trazodone 401.4mg/day, and venlafaxine 149.4mg/day. Sensitivity analyses corroborated the results except for doxepin. The number of studies for some drugs was small. The current method assumes dose response relationship of antidepressants. Our findings can be useful for clinicians when they switch antidepressants and for researchers when they compare various antidepressants in their research. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  9. A new concept in radiation dose calculation by using of 1 cm dose equivalent rate constant with shielding effect and accompanying software

    International Nuclear Information System (INIS)

    Nakamura, Ayako; Yamano, Toyotsugu

    2000-01-01

    A new concept called 1 cm dose equivalent rate constant with shielding effect is introduced for estimation of radiation dose. This new concept represents an expansion of the former standard 1 cm dose equivalent rate constant (defined as μSv·m 2 ·MBq -1 ·h -1 ) adjusted attenuation for any given thickness of shielding material (iron, lead and concrete). The 1 cm dose equivalent rate constant with shielding effect for various shielding conditions can be rapidly computed with a free-software application, KINGS-B621, which may be easily downloaded from the internet. The computed rate constants can be put out as text files which are compatible with commercially available spread-sheet software, so it is easy for users to apply the data to creation of documents concerning radiation dose. (author)

  10. Comparison of dose calculation algorithms in slab phantoms with cortical bone equivalent heterogeneities

    International Nuclear Information System (INIS)

    Carrasco, P.; Jornet, N.; Duch, M. A.; Panettieri, V.; Weber, L.; Eudaldo, T.; Ginjaume, M.; Ribas, M.

    2007-01-01

    To evaluate the dose values predicted by several calculation algorithms in two treatment planning systems, Monte Carlo (MC) simulations and measurements by means of various detectors were performed in heterogeneous layer phantoms with water- and bone-equivalent materials. Percentage depth doses (PDDs) were measured with thermoluminescent dosimeters (TLDs), metal-oxide semiconductor field-effect transistors (MOSFETs), plane parallel and cylindrical ionization chambers, and beam profiles with films. The MC code used for the simulations was the PENELOPE code. Three different field sizes (10x10, 5x5, and 2x2 cm 2 ) were studied in two phantom configurations and a bone equivalent material. These two phantom configurations contained heterogeneities of 5 and 2 cm of bone, respectively. We analyzed the performance of four correction-based algorithms and one based on convolution superposition. The correction-based algorithms were the Batho, the Modified Batho, the Equivalent TAR implemented in the Cadplan (Varian) treatment planning system (TPS), and the Helax-TMS Pencil Beam from the Helax-TMS (Nucletron) TPS. The convolution-superposition algorithm was the Collapsed Cone implemented in the Helax-TMS. All the correction-based calculation algorithms underestimated the dose inside the bone-equivalent material for 18 MV compared to MC simulations. The maximum underestimation, in terms of root-mean-square (RMS), was about 15% for the Helax-TMS Pencil Beam (Helax-TMS PB) for a 2x2 cm 2 field inside the bone-equivalent material. In contrast, the Collapsed Cone algorithm yielded values around 3%. A more complex behavior was found for 6 MV where the Collapsed Cone performed less well, overestimating the dose inside the heterogeneity in 3%-5%. The rebuildup in the interface bone-water and the penumbra shrinking in high-density media were not predicted by any of the calculation algorithms except the Collapsed Cone, and only the MC simulations matched the experimental values within

  11. Comparison of dose calculation algorithms in slab phantoms with cortical bone equivalent heterogeneities.

    Science.gov (United States)

    Carrasco, P; Jornet, N; Duch, M A; Panettieri, V; Weber, L; Eudaldo, T; Ginjaume, M; Ribas, M

    2007-08-01

    To evaluate the dose values predicted by several calculation algorithms in two treatment planning systems, Monte Carlo (MC) simulations and measurements by means of various detectors were performed in heterogeneous layer phantoms with water- and bone-equivalent materials. Percentage depth doses (PDDs) were measured with thermoluminescent dosimeters (TLDs), metal-oxide semiconductor field-effect transistors (MOSFETs), plane parallel and cylindrical ionization chambers, and beam profiles with films. The MC code used for the simulations was the PENELOPE code. Three different field sizes (10 x 10, 5 x 5, and 2 x 2 cm2) were studied in two phantom configurations and a bone equivalent material. These two phantom configurations contained heterogeneities of 5 and 2 cm of bone, respectively. We analyzed the performance of four correction-based algorithms and one based on convolution superposition. The correction-based algorithms were the Batho, the Modified Batho, the Equivalent TAR implemented in the Cadplan (Varian) treatment planning system (TPS), and the Helax-TMS Pencil Beam from the Helax-TMS (Nucletron) TPS. The convolution-superposition algorithm was the Collapsed Cone implemented in the Helax-TMS. All the correction-based calculation algorithms underestimated the dose inside the bone-equivalent material for 18 MV compared to MC simulations. The maximum underestimation, in terms of root-mean-square (RMS), was about 15% for the Helax-TMS Pencil Beam (Helax-TMS PB) for a 2 x 2 cm2 field inside the bone-equivalent material. In contrast, the Collapsed Cone algorithm yielded values around 3%. A more complex behavior was found for 6 MV where the Collapsed Cone performed less well, overestimating the dose inside the heterogeneity in 3%-5%. The rebuildup in the interface bone-water and the penumbra shrinking in high-density media were not predicted by any of the calculation algorithms except the Collapsed Cone, and only the MC simulations matched the experimental values

  12. Measurements of the neutron dose equivalent for various radiation qualities, treatment machines and delivery techniques in radiation therapy.

    Science.gov (United States)

    Hälg, R A; Besserer, J; Boschung, M; Mayer, S; Lomax, A J; Schneider, U

    2014-05-21

    In radiation therapy, high energy photon and proton beams cause the production of secondary neutrons. This leads to an unwanted dose contribution, which can be considerable for tissues outside of the target volume regarding the long term health of cancer patients. Due to the high biological effectiveness of neutrons in regards to cancer induction, small neutron doses can be important. This study quantified the neutron doses for different radiation therapy modalities. Most of the reports in the literature used neutron dose measurements free in air or on the surface of phantoms to estimate the amount of neutron dose to the patient. In this study, dose measurements were performed in terms of neutron dose equivalent inside an anthropomorphic phantom. The neutron dose equivalent was determined using track etch detectors as a function of the distance to the isocenter, as well as for radiation sensitive organs. The dose distributions were compared with respect to treatment techniques (3D-conformal, volumetric modulated arc therapy and intensity-modulated radiation therapy for photons; spot scanning and passive scattering for protons), therapy machines (Varian, Elekta and Siemens linear accelerators) and radiation quality (photons and protons). The neutron dose equivalent varied between 0.002 and 3 mSv per treatment gray over all measurements. Only small differences were found when comparing treatment techniques, but substantial differences were observed between the linear accelerator models. The neutron dose equivalent for proton therapy was higher than for photons in general and in particular for double-scattered protons. The overall neutron dose equivalent measured in this study was an order of magnitude lower than the stray dose of a treatment using 6 MV photons, suggesting that the contribution of the secondary neutron dose equivalent to the integral dose of a radiotherapy patient is small.

  13. Determination of the conversion coefficient for ambient dose equivalent, H(10), from air kerma measurements

    International Nuclear Information System (INIS)

    Gonzalez J, F.; Alvarez R, J. T.

    2015-09-01

    Namely the operational magnitudes can be determined by the product of a conversion coefficient by exposure air kerma or fluence, etc. In particular in Mexico for the first time is determined the conversion coefficient (Cc) for operational magnitude Environmental Dose Equivalent H(10) by thermoluminescence dosimetry (TLD) technique. First 30 TLD-100 dosimeters are calibrated in terms of air kerma, then these dosimeters are irradiated inside a sphere ICRU type of PMMA and with the aid of theory cavity the absorbed dose in PMMA is determined at a depth of 10 mm within the sphere D PMMA (10), subsequently absorbed dose to ICRU tissue is corrected and the dose equivalent H(10) is determined. The Cc is determined as the ratio of H(10)/K a obtaining a value of 1.20 Sv Gy -1 with a u c = 3.66%, this being consistent with the published value in ISO-4037-3 of 1.20 Sv Gy -1 with a u c = 2%. (Author)

  14. Development of neutron dosimeter using CR-39 for measurement of ambient dose equivalent

    International Nuclear Information System (INIS)

    Maki, Daisuke; Shinozaki, Wakako; Ohguchi, Hiroyuki; Yamamoto, Takayoshi; Nakamura, Takayoshi

    2010-01-01

    A CR-39 has good advantages such as cumulative type dosimeter, small fading effect and gamma-ray insensitive. Therefore, we developed the wide energy-range environmental neutron dosimeter using eight CR-39s for area monitoring in this study. This dosimeter is made of octagonal columnar polyethylene block which height is 60 mm and bottom side is 25 mm. The dosimeter contains two types of CR-39s for fast neutron detection and slow neutron detection. Four CR-39s for fast neutron detection are used for detection of recoil protons produced by H (n, p) reactions. Four CR-39s for slow neutron detection are used with boron nitride converter to detect alpha-rays produced by 10 B (n, α) 7 Li reactions. Ambient dose equivalent is obtained by adding the number of etch-pits observed in four CR-39s for fast neutron detection to the number of etch-pits observed in four CR-39s for slow neutron detection with appropriate constants respectively. Dosimeters were irradiated with some energetic neutrons and evaluated results of ambient dose equivalent were compared with results from neutron transport calculations. Energy response of dosimeter shows good agreement with neutron fluence to ambient dose equivalent conversion coefficients. Directional dependence of dosimeter is at the same level as the rem-counter. (author)

  15. Determination of eye lenses dose equivalent in terms of Hp(3)

    International Nuclear Information System (INIS)

    Klamert, V.; Caresana, M.; Minchillo, G.; Tambussi, O.

    2002-01-01

    The Italian radioprotection legislation requires the determination of personal dose equivalent in terms of H p (10) and H p (0.07) and the determination of the eye lenses dose equivalent in terms of H p (3). Whereas the calibration of a dosemeter for the determination of H p (10) and H p (0.07) is feasible, the calibration of a dosemeter in terms of H p (3) is impossible, owing to the absence of the suitable phantom and the conversion coefficients h pk (3) from air kerma to H p (3). Using an anthropomorphic phantom for the irradiation, the aim of this work is to determine the experimental values of the conversion coefficients and to relate the result of the dosemeter worn on the forehead with the dose equivalent to the eye lenses. The study is performed in the X energy range from 30 keV to 100 keV, i.e. the one most widely used in medical practices

  16. Reduction of outdoor and indoor ambient dose equivalent after decontamination in the Fukushima evacuation zones

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida-Ohuchi, Hiroko; Kanagami, Takashi [Graduate School of Pharmaceutical Sciences, Tohoku University, Miyagi (Japan); Naitoh, Yutaka; Kameyama, Mizuki [Japan Environment Research Co., Ltd., Miyagi (Japan); Hosoda, Masahiro [Dept. of Radiological Life Sciences, Hirosaki University Graduate School of Health Sciences, Aomori (Japan)

    2017-03-15

    One of the most urgent issues following the accident at the Fukushima Daiichi nuclear power plant (FDNPP) was the remediation of the land, in particular, for residential area contaminated by the radioactive materials discharged. In this study, the effect of decontamination on reduction of ambient dose equivalent outdoors and indoors was evaluated. The latter is essential for residents as most individuals spend a large portion of their time indoors. From December 2012 to November 2014, thirty-seven Japanese single-family detached wooden houses were investigated before and after decontamination in evacuation zones. Outdoor and indoor dose measurements (n=84 and 114, respectively) were collected based on in situ measurements using the NaI (Tl) scintillation surveymeter. The outdoor ambient dose equivalents [H{sup *}(10){sub out}] ranged from 0.61 to 3.71 μSv h{sup -1} and from 0.23 to 1.32 μSv h{sup -1} before and after decontamination, respectively. The indoor ambient dose equivalents [H{sup *}(10){sup in}] ranged from 0.29 to 2.53 μSv h{sup -1} and from 0.16 to 1.22 μSv h{sup -1} before and after decontamination, respectively. The values of reduction efficiency (RE), defined as the ratio by which the radiation dose has been reduced via decontamination, were evaluated as 0.47±0.13, 0.51±0.13, and 0.58±0.08 (average±σ) when H{sup *}(10){sub out} <1.0 μSv h{sup -1}, 1.0 μSv h{sup -1} dose is essential as most individuals spend a large portion of their time indoors. The difference between outdoors and indoors should be considered carefully in order to estimate residents’ exposure dose before their returning home.

  17. Assessment of equivalent dose on the lens in cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, M. V. L.; Campos, P. S. F. [Federal University of Bahia, Department of Health Sciences, Salvador (Brazil); Andrade, M. E. A. [Federal University of Pernambuco, Department of Nuclear Energy, Recife (Brazil); Soares, M. R. [Federal University of Sergipe, Department of Physics, Sao Cristovao (Brazil); Batista, W. O., E-mail: marcusradiology@gmail.com [Federal Institute of Bahia, Department of Applied Sciences, 40.301-015 Salvador (Brazil)

    2014-08-15

    The Cone Beam Computed Tomography (CBCT) is presented as a useful test method for the evaluation of craniofacial structures. Among them stands the temporomandibular joint (T MJ) imaging as complementary to clinical evaluation. It must be considered that there is no reference levels established for diagnosis of this imaging modality. In this same context, recently the limit for crystalline lens was reviewed by ICRP which set new values to the equivalent dose. The aim of this study was to evaluate the kerma at the surface of the crystalline lens in T MJ CBCT and derive the equivalent dose. It was used an anthropomorphic phantom of the head and neck (manufactured by: Radiation Support Devices, model; Rs-230) containing equivalent tissue with dimensions of a typical patient. The dosimetric measurements were obtained by using seven pairs of thermoluminescent dosimetry (TLD) dosimeters (LiF: Mg, Ti) positioned on the surface of the crystalline lens, divided into two pairs (one pair for each eye) per scanner evaluated. The tomographic images were obtained in three CBCT equipment s (Kodak 9000, Gendex GXCB 500 and i-Cat). Values of equivalent dose obtained were: 5.82 mSv (Kodak 9000); 5.38 mSv (Gendex GXCB 500) and 7.98 mSv (i-Cat). These results demonstrate that for this type of procedure the doses are below the annual limit but may vary in accordance with the scanner and the exposure factors used in the image acquisition. The Gendex GXCB500 uses larger Fov and higher kV. It results in levels close to those obtained on Kodak 9000. Larger doses are associated with the i-Cat. Another factor that rises is the repetition of examinations due to positioning errors and / or patient movement, which may exceed the annual limit established by ICRP. Although the ICRP limits are not applied to medical exposures, it is advisable to consider the sensitivity of the organ. For this reason, it is concluded that doses per T MJ procedure on CBCT are below the annual limit and may vary

  18. Estimation of equivalent dose on the ends of hemodynamic physicians during neurological procedures; Avaliacao da dose equivalente nas extremidades de medicos hemodinamicistas durante procedimentos neurologicos

    Energy Technology Data Exchange (ETDEWEB)

    Squair, Peterson L.; Souza, Luiz C. de; Oliveira, Paulo Marcio C. de [Universidade FUMEC, Belo Horizonte, MG (Brazil). Radiologia e Protecao Radiologica; Nogueira, Maria do S. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2005-07-01

    The estimation of doses in the hands of physicists during hemodynamic procedures is important to verify the application of radiation protection related to the optimization and limit of dose, principles required by the Portaria 453/98 of Ministry of Health/ANVISA, Brazil. It was checked the levels of exposure of the hands of doctors during the use of the equipment in hemodynamic neurological procedures through dosimetric rings with thermoluminescent dosemeters detectors of LiF: Mg, Ti (TLD-100), calibrated in personal Dose equivalent HP (0.07). The average equivalent dose in the end obtained was 41.12. {mu}Sv per scan with an expanded uncertainty of 20% for k = 2. This value is relative to the hemodynamic Neurology procedure using radiological protection procedures accessible to minimize the dose.

  19. A new online detector for estimation of peripheral neutron equivalent dose in organ

    Energy Technology Data Exchange (ETDEWEB)

    Irazola, L., E-mail: leticia@us.es; Sanchez-Doblado, F. [Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla 41009, Spain and Servicio de Radiofísica, Hospital Universitario Virgen Macarena, Sevilla 41007 (Spain); Lorenzoli, M.; Pola, A. [Departimento di Ingegneria Nuclear, Politecnico di Milano, Milano 20133 (Italy); Bedogni, R. [Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare (INFN), Frascati Roma 00044 (Italy); Terrón, J. A. [Servicio de Radiofísica, Hospital Universitario Virgen Macarena, Sevilla 41007 (Spain); Sanchez-Nieto, B. [Instituto de Física, Pontificia Universidad Católica de Chile, Santiago 4880 (Chile); Expósito, M. R. [Departamento de Física, Universitat Autònoma de Barcelona, Bellaterra 08193 (Spain); Lagares, J. I.; Sansaloni, F. [Centro de Investigaciones Energéticas y Medioambientales y Tecnológicas (CIEMAT), Madrid 28040 (Spain)

    2014-11-01

    Purpose: Peripheral dose in radiotherapy treatments represents a potential source of secondary neoplasic processes. As in the last few years, there has been a fast-growing concern on neutron collateral effects, this work focuses on this component. A previous established methodology to estimate peripheral neutron equivalent doses relied on passive (TLD, CR39) neutron detectors exposed in-phantom, in parallel to an active [static random access memory (SRAMnd)] thermal neutron detector exposed ex-phantom. A newly miniaturized, quick, and reliable active thermal neutron detector (TNRD, Thermal Neutron Rate Detector) was validated for both procedures. This first miniaturized active system eliminates the long postprocessing, required for passive detectors, giving thermal neutron fluences in real time. Methods: To validate TNRD for the established methodology, intrinsic characteristics, characterization of 4 facilities [to correlate monitor value (MU) with risk], and a cohort of 200 real patients (for second cancer risk estimates) were evaluated and compared with the well-established SRAMnd device. Finally, TNRD was compared to TLD pairs for 3 generic radiotherapy treatments through 16 strategic points inside an anthropomorphic phantom. Results: The performed tests indicate similar linear dependence with dose for both detectors, TNRD and SRAMnd, while a slightly better reproducibility has been obtained for TNRD (1.7% vs 2.2%). Risk estimates when delivering 1000 MU are in good agreement between both detectors (mean deviation of TNRD measurements with respect to the ones of SRAMnd is 0.07 cases per 1000, with differences always smaller than 0.08 cases per 1000). As far as the in-phantom measurements are concerned, a mean deviation smaller than 1.7% was obtained. Conclusions: The results obtained indicate that direct evaluation of equivalent dose estimation in organs, both in phantom and patients, is perfectly feasible with this new detector. This will open the door to an

  20. Ambient neutron dose equivalent during proton therapy using wobbling scanning system: Measurements and calculations

    Science.gov (United States)

    Lin, Yung-Chieh; Lee, Chung-Chi; Chao, Tsi-Chian; Tsai, Hui-Yu

    2017-11-01

    Neutron production is a concern in proton therapy, particularly in scattering proton beam delivery systems. Despite this fact, little is known about the effects of secondary neutron exposure around wobbling scattered proton treatment nozzles. The objective of this study was to estimate the neutron dose level resulting from the use of a wobbling scattered proton treatment unit. We applied the Monte Carlo method for predict the ambient neutron dose equivalent, H*(10), per absorbed dose at the treatment isocenter, D, in the proton therapy center of Chang Gung Memorial Hospital, Linkou, Taiwan. For a 190-MeV proton beam, H* (10) / D values typically decreased with the distance from the isocenter, being 1.106 mSv/Gy at the isocenter versus 0.112 mSv/Gy at a distance of 150 cm from the isocenter. The H* (10) / D values generally decreased as the neutron receptors moved away from the isocenter, and increased when the angle from the initial beam axis increased. The ambient neutron dose equivalents were observed to be slightly lower in the direction of multileaf collimator movement. For radiation protection, the central axis of a proton-treated patient is suggested to be at the 0° angle of the beam. If the beam direction at the 90° angle is necessary, the patient axis is suggested to be along with the direction of MLC movement. Our study provides the neutron dose level and neutron energy fluence for the first wobbling proton system at the proton therapy center of Chang Gung Memorial Hospital.

  1. A new online detector for estimation of peripheral neutron equivalent dose in organ

    International Nuclear Information System (INIS)

    Irazola, L.; Sanchez-Doblado, F.; Lorenzoli, M.; Pola, A.; Bedogni, R.; Terrón, J. A.; Sanchez-Nieto, B.; Expósito, M. R.; Lagares, J. I.; Sansaloni, F.

    2014-01-01

    Purpose: Peripheral dose in radiotherapy treatments represents a potential source of secondary neoplasic processes. As in the last few years, there has been a fast-growing concern on neutron collateral effects, this work focuses on this component. A previous established methodology to estimate peripheral neutron equivalent doses relied on passive (TLD, CR39) neutron detectors exposed in-phantom, in parallel to an active [static random access memory (SRAMnd)] thermal neutron detector exposed ex-phantom. A newly miniaturized, quick, and reliable active thermal neutron detector (TNRD, Thermal Neutron Rate Detector) was validated for both procedures. This first miniaturized active system eliminates the long postprocessing, required for passive detectors, giving thermal neutron fluences in real time. Methods: To validate TNRD for the established methodology, intrinsic characteristics, characterization of 4 facilities [to correlate monitor value (MU) with risk], and a cohort of 200 real patients (for second cancer risk estimates) were evaluated and compared with the well-established SRAMnd device. Finally, TNRD was compared to TLD pairs for 3 generic radiotherapy treatments through 16 strategic points inside an anthropomorphic phantom. Results: The performed tests indicate similar linear dependence with dose for both detectors, TNRD and SRAMnd, while a slightly better reproducibility has been obtained for TNRD (1.7% vs 2.2%). Risk estimates when delivering 1000 MU are in good agreement between both detectors (mean deviation of TNRD measurements with respect to the ones of SRAMnd is 0.07 cases per 1000, with differences always smaller than 0.08 cases per 1000). As far as the in-phantom measurements are concerned, a mean deviation smaller than 1.7% was obtained. Conclusions: The results obtained indicate that direct evaluation of equivalent dose estimation in organs, both in phantom and patients, is perfectly feasible with this new detector. This will open the door to an

  2. Efficiency improvement in proton dose calculations with an equivalent restricted stopping power formalism

    Science.gov (United States)

    Maneval, Daniel; Bouchard, Hugo; Ozell, Benoît; Després, Philippe

    2018-01-01

    The equivalent restricted stopping power formalism is introduced for proton mean energy loss calculations under the continuous slowing down approximation. The objective is the acceleration of Monte Carlo dose calculations by allowing larger steps while preserving accuracy. The fractional energy loss per step length ɛ was obtained with a secant method and a Gauss-Kronrod quadrature estimation of the integral equation relating the mean energy loss to the step length. The midpoint rule of the Newton-Cotes formulae was then used to solve this equation, allowing the creation of a lookup table linking ɛ to the equivalent restricted stopping power L eq, used here as a key physical quantity. The mean energy loss for any step length was simply defined as the product of the step length with L eq. Proton inelastic collisions with electrons were added to GPUMCD, a GPU-based Monte Carlo dose calculation code. The proton continuous slowing-down was modelled with the L eq formalism. GPUMCD was compared to Geant4 in a validation study where ionization processes alone were activated and a voxelized geometry was used. The energy straggling was first switched off to validate the L eq formalism alone. Dose differences between Geant4 and GPUMCD were smaller than 0.31% for the L eq formalism. The mean error and the standard deviation were below 0.035% and 0.038% respectively. 99.4 to 100% of GPUMCD dose points were consistent with a 0.3% dose tolerance. GPUMCD 80% falloff positions (R80 ) matched Geant’s R80 within 1 μm. With the energy straggling, dose differences were below 2.7% in the Bragg peak falloff and smaller than 0.83% elsewhere. The R80 positions matched within 100 μm. The overall computation times to transport one million protons with GPUMCD were 31-173 ms. Under similar conditions, Geant4 computation times were 1.4-20 h. The L eq formalism led to an intrinsic efficiency gain factor ranging between 30-630, increasing with the prescribed accuracy of simulations. The

  3. Understanding differences in dose-equivalents reported by passive and electronic personal dosemeters

    International Nuclear Information System (INIS)

    Perks, Christopher A.; Burgess, Peter; Smith, David; Salasky, Mark; Yahnke, Cliff

    2008-01-01

    Full text: In a number of challenging environments, clients occasionally double badge with electronic personal dosemeters (EPDs) to ensure day-to-day management of their employees personal dose-equivalent while using passive (in our case Luxel or InLight) dosemeters for monthly monitoring for approved results for dose record keeping. In some cases there have been significant differences in the cumulative doses recorded by the EPDs and the passive dosemeters. In these circumstances the passive dosemeters usually report a higher dose than the EPD by up to a factor of two, though more commonly 1.3. In this paper we describe the differences seen between EPD and passive dosemeters (in a number of countries). We then examine the possible causes for such discrepancies by comparison with published response function data available for the EPDs and Landauer dosemeters. We have undertaken a number of experiments comparing directly a number of EPDs and passive dosemeter response to a variety of energy and complex angular geometries where the two types of dosimeter have been exposed at the same time. Recommendations will be made on the appropriate use of double badging in difficult environments and interpretation of the results. (author)

  4. Procedures for operational monitoring of the environmental equivalent doses in cobalt therapy

    International Nuclear Information System (INIS)

    Perez Velasquez, Reytel; Gonzalez Lopez, Nadia; Perez Tamayo, Luis

    2009-01-01

    It took as its object of study environmental equivalent dose rates of field radiation they face radiophysicists technicians and medical physicists in the irradiation site of the radiation department of Lenin Hospital in Holguin, and the public that travels or remains in premises and areas surrounding the campus. It A review of national and international publications as well as technical documents to study the state of the art of the methodological existing monitoring of those dose rates and the valuation of impact in the context of an environmental management system. Since no detailed instructions and to perform the above-mentioned monitoring was proposed structure should contain a procedure to regulate the steps for this monitoring in the radiotherapy department of the Lenin Hospital Holguin, for which we studied the guidelines of NC ISO 14000 , and was conducted wide experiment whose led to: illustrate the level of doses required workers exposed occupationally exposed to radiation and the public compare these levels with natural radiation sources, assess the effectiveness of shielding the site of irradiation and the points of greatest risk within and outside the enclosure irradiation.Also assessed the impact it can have on the health of people exposed to such doses. Finally, we proposed a procedure for conducting subsequent monitoring and made recommendations to reduce levels radiation determined the lowest level reasonably achievable. (author)

  5. Long-term predictions of ambient dose equivalent rates after the Fukushima Daiichi nuclear power plant accident

    International Nuclear Information System (INIS)

    Kinase, Sakae; Saito, Kimiaki; Takahashi, Tomoyuki

    2017-01-01

    To analyze radiation protection strategies and rehabilitation programs in Fukushima, prediction models have been developed for ambient dose equivalent rate distributions within the 80 km-radius around the Fukushima Daiichi nuclear power plant. The prediction models characterized by ecological half-lives of radioactive caesium for land-use, enable Fukushima residents to obtain distribution maps of ambient dose equivalent rates after the Fukushima Daiichi nuclear power plant accident. Model parameters such as the ecological half-lives for the short-term component and the fractional distribution of short-term component were evaluated using ambient dose equivalent rates through car/vehicle-borne surveys. It was found that the ecological half-lives among land-use differ only slightly, whereas the fractional distributions of the short-term component are clearly dependent on land-use. In addition, uncertainties concerning predictions of ambient dose equivalent rates arising from variability in model parameters were assessed using Monte Carlo simulations. Long-term changes of ambient dose equivalent rates were predicted for different land-use areas. Distribution maps of ambient dose equivalent rates for the next 30 years after the accident, created by the prediction models are expected to be useful for follow-up of the radiological situation since they provide information on the space variation of the ambient dose equivalent rates in inhabited areas. (author)

  6. Improvement of the equivalent sphere model for better estimates of skin or eye dose in space radiation environments

    International Nuclear Information System (INIS)

    Lin, Z.W.

    2011-01-01

    It is often useful to get a quick estimate of the dose or dose equivalent of an organ, such as blood-forming organs, the eye or the skin, in a radiation field. Sometimes an equivalent sphere is used to represent the organ for this purpose. For space radiation environments, recently it has been shown that the equivalent sphere model does not work for the eye or the skin in solar particle event environments. In this study, we improve the representation of the eye and the skin using a two-component equivalent sphere model. Motivated by the two-peak structure of the body organ shielding distribution for the eye and the skin, we use an equivalent sphere with two radius parameters, for example a partial spherical shell of a smaller thickness over a proper fraction of the full solid angle combined with a concentric partial spherical shell of a larger thickness over the rest of the full solid angle, to represent the eye or the skin. We find that using an equivalent sphere with two radius parameters instead of one drastically improves the accuracy of the estimates of dose and dose equivalent in space radiation environments. For example, in solar particle event environments the average error in the estimate of the skin dose equivalent using an equivalent sphere with two radius parameters is about 8%, while the average error of the conventional equivalent sphere model using one radius parameter is around 100%.

  7. Radiation protection instrumentation ambient and/or directional dose equivalent (rate) meters and/or monitors for beta, X and gamma radiation

    International Nuclear Information System (INIS)

    2004-01-01

    This international standard applies to dose equivalent (rate) meters and/or monitors for the measurement of ambient dose equivalent (rate) and/or directional dose equivalent (rate) from external beta, X and gamma radiation, as recommended in ICRU report 47. Note 1: if both quantities, ambient dose equivalent and directional dose equivalent are meant, the term dose equivalent may be used as an abbreviation. It applies directly to dose equivalent (rate) meters intended for the determination of the dose equivalent or dose equivalent rate from external beta and/or X and gamma radiation of energies up to 10 MeV for radiation protection purposes. In this document, the expression 'dose equivalent (rate)' is used when the provisions apply to both measurement of dose equivalent and the measurement of dose equivalent rate. Note 2: It does not apply to medical radiology which is within the scope of technical committee 62, where the conditions of radiation exposure may be extremely inhomogeneous, but precisely known. Note 3 It does not apply directly to instruments intended to be worn by an individual for the purpose of estimating the radiation dose received by that individual. The object of this standard is to specify the design requirements and the performance characteristics of dose equivalent ( rate) meters intended for the determination of ambient dose equivalent ( rate) and directional dose equivalent (rate) as defined in ICRU Report 47. Accordingly, this standard specifies: a) general characteristics, the functions and performance characteristics of dose equivalent (rate) meters; b) the methods of test to be used to determine compliance with requirements of this standard. (ICRU Report 47: 1992, Measurements of dose equivalents from external photons and electron radiations, International Commission on Radiation Units and Measurements, 7910 Woodmont Avenue, Bethesda, Maryland 20814-3095, U.S.A.). (N.C.)

  8. Dynamics of effective dose equivalent in the RSFSR from 90Sr and 137Cs dietary intake

    International Nuclear Information System (INIS)

    Prokof'ev, O.N.; Antonova, V.A.; Golubeva, T.N.

    1987-01-01

    This paper generalizes the long-term observations (1979-1984 Years) of the contents of stratospheric fallout 90 Sr and 137 Cs in main food products and soils of different areas of the USSR. Also, the information is given on 90 Sr content in the human body from the analyses of bone tissue samples and extracted teeth. On the basis of 90 Sr determined in various skeletal tissues and of 137 Cs dietary intake was obtained the dynamics of effective dose equivalent for population of the RSFSR. (author)

  9. Emphysema quantification and lung volumetry in chest X-ray equivalent ultralow dose CT - Intra-individual comparison with standard dose CT.

    Science.gov (United States)

    Messerli, Michael; Ottilinger, Thorsten; Warschkow, René; Leschka, Sebastian; Alkadhi, Hatem; Wildermuth, Simon; Bauer, Ralf W

    2017-06-01

    To determine whether ultralow dose chest CT with tin filtration can be used for emphysema quantification and lung volumetry and to assess differences in emphysema measurements and lung volume between standard dose and ultralow dose CT scans using advanced modeled iterative reconstruction (ADMIRE). 84 consecutive patients from a prospective, IRB-approved single-center study were included and underwent clinically indicated standard dose chest CT (1.7±0.6mSv) and additional single-energy ultralow dose CT (0.14±0.01mSv) at 100kV and fixed tube current at 70mAs with tin filtration in the same session. Forty of the 84 patients (48%) had no emphysema, 44 (52%) had emphysema. One radiologist performed fully automated software-based pulmonary emphysema quantification and lung volumetry of standard and ultralow dose CT with different levels of ADMIRE. Friedman test and Wilcoxon rank sum test were used for multiple comparison of emphysema and lung volume. Lung volumes were compared using the concordance correlation coefficient. The median low-attenuation areas (LAA) using filtered back projection (FBP) in standard dose was 4.4% and decreased to 2.6%, 2.1% and 1.8% using ADMIRE 3, 4, and 5, respectively. The median values of LAA in ultralow dose CT were 5.7%, 4.1% and 2.4% for ADMIRE 3, 4, and 5, respectively. There was no statistically significant difference between LAA in standard dose CT using FBP and ultralow dose using ADMIRE 4 (p=0.358) as well as in standard dose CT using ADMIRE 3 and ultralow dose using ADMIRE 5 (p=0.966). In comparison with standard dose FBP the concordance correlation coefficients of lung volumetry were 1.000, 0.999, and 0.999 for ADMIRE 3, 4, and 5 in standard dose, and 0.972 for ADMIRE 3, 4 and 5 in ultralow dose CT. Ultralow dose CT at chest X-ray equivalent dose levels allows for lung volumetry as well as detection and quantification of emphysema. However, longitudinal emphysema analyses should be performed with the same scan protocol and

  10. Measurement of dose equivalent distribution on-board commercial jet aircraft

    International Nuclear Information System (INIS)

    Kubancak, J.; Ambrozova, I.; Ploc, O.; Pachnerova Brabcova, K.; Stepan, V.; Uchihori, Y.

    2014-01-01

    The annual effective doses of aircrew members often exceed the limit of 1 mSv for the public due to the increased level of cosmic radiation at the flight altitudes, and thus, it is recommended to monitor them [International Commission on Radiation Protection. 1990 Recommendations of the International Commission on Radiological Protection. ICRP Publication 60. Ann. ICRP 21(1-3), (1991)]. According to the Monte Carlo simulations [Battistoni, G., Ferrari, A., Pelliccioni, M. and Villari, R. Evaluation of the doses to aircrew members taking into consideration the aircraft structures. Adv. Space Res. 36, 1645-1652 (2005) and Ferrari, A., Pelliccioni, M. and Villari, R. Evaluation of the influence of aircraft shielding on the aircrew exposure through an aircraft mathematical model. Radiat. Prot. Dosim. 108(2), 91-105 (2004)], the ambient dose equivalent rate H*(10) depends on the location in the aircraft. The aim of this article is to experimentally evaluate H*(10) on-board selected types of aircraft. The authors found that H*(10) values are higher in the front and the back of the cabin and lesser in the middle of the cabin. Moreover, total dosimetry characteristics obtained in this way are in a reasonable agreement with other data, in particular with the above-mentioned simulations. (authors)

  11. Spatial analysis of ambient gamma dose equivalent rate data by means of digital image processing techniques.

    Science.gov (United States)

    Szabó, Katalin Zsuzsanna; Jordan, Gyozo; Petrik, Attila; Horváth, Ákos; Szabó, Csaba

    2017-01-01

    A detailed ambient gamma dose equivalent rate mapping based on field measurements at ground level and at 1 m height was carried out at 142 sites in 80 × 90 km area in Pest County, Hungary. Detailed digital image processing analysis was carried out to identify and characterise spatial features such as outlying points, anomalous zones and linear edges in a smoothed TIN interpolated surface. The applied method proceeds from the simple shaded relief model and digital cross-sections to the more complex gradient magnitude and gradient direction maps, 2nd derivative profile curvature map, relief map and lineament density map. Each map is analysed for statistical characteristics and histogram-based image segmentation is used to delineate areas homogeneous with respect to the parameter values in these maps. Assessment of spatial anisotropy is implemented by 2D autocorrelogram and directional variogram analyses. The identified spatial features are related to underlying geological and tectonic conditions using GIS technology. Results show that detailed digital image processing is efficient in revealing the pattern present in field-measured ambient gamma dose equivalent rates and they are related to regional scale tectonic zones and surface sedimentary lithological conditions in the study area. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Evaluation of the directional dose equivalent H,(0.07) for ring dosemeters

    International Nuclear Information System (INIS)

    Alvarez R, J.T.; Tovar M, V.M.

    2006-01-01

    The personnel dosimetry laboratory (LDP) of the Metrology department received an user's of radiation beta application that incidentally had irradiated 14 couples of ring dosemeters for extremities of the type TLD-100 given by the LDP. This sample of 14 couples of rings tentatively it was irradiated in the months of July-August of the year 2004, and he requested in an expedite way the evaluation of the received dose equivalent. The LSCD builds two calibration curves in terms of the directional dose equivalent H'(0.07) using two sources patterns of 90 Sr- 90 Y for beta radiation: one of 74 MBq and another of 1850 MBq with traceability to the PTB. The first curve in the interval of 0 to 5 mSv, the second in the range of 5 to 50 mSv, taking into account effects by positioned of the rings in the phantom. Both calibration curves were validated by adjustment lack, symmetry of residuals and normality of the same ones. It is evaluated and analyzing the H'(0.007) for these 14 couples of rings using the Tukey test of media of a single road. It was found that the H , its could be classified in 4 groups, and that the probability that its has irradiated in a random way it was smaller to the level at α = 0.05. (Author)

  13. Equivalent dose measurements on board an Armenian Airline flight and Concord (9-17 km)

    International Nuclear Information System (INIS)

    Akopova, A.B.; Melkonyan, A.A.; Tatikyan, S.Sh.; Capdevielle, J-N.

    2002-01-01

    The results of investigations of the neutron component (E=1-10 MeV) of cosmic radiation on board the 'Armenian Airlines' aircrafts using nuclear photoemulsion are presented. The emulsions were exposed on the flights from Yerevan to Moscow, St.-Petersburg, Beirut, Athens, Frankfurt, Amsterdam, Paris and Sofia, and on Concord supersonic flights from Paris to New York. The dependence of the neutron fluxes, and on absorbed and equivalent doses on the flight parameters were investigated. On the flights of the supersonic Concord, with an altitude of 17 km, the neutron fluxes were essentially higher in comparison to those measured on Armenian airliners. It is interesting to note, that the neutron flux and equivalent dose rate decrease with altitude up to 470 km in space, for example, on board the STS-57. The shape of the differential energy spectrum for fast neutrons is the same on all Armenian airlines flights, but significantly different at 17 km altitude, where the flux in the energy region above 3 MeV is increasing

  14. Equivalent dose measurements on board an Armenian Airline flight and Concord (9-17 km)

    Energy Technology Data Exchange (ETDEWEB)

    Akopova, A.B. E-mail: akopova@lx2.yerphi.am; Melkonyan, A.A.; Tatikyan, S.Sh.; Capdevielle, J-N

    2002-12-01

    The results of investigations of the neutron component (E=1-10 MeV) of cosmic radiation on board the 'Armenian Airlines' aircrafts using nuclear photoemulsion are presented. The emulsions were exposed on the flights from Yerevan to Moscow, St.-Petersburg, Beirut, Athens, Frankfurt, Amsterdam, Paris and Sofia, and on Concord supersonic flights from Paris to New York. The dependence of the neutron fluxes, and on absorbed and equivalent doses on the flight parameters were investigated. On the flights of the supersonic Concord, with an altitude of 17 km, the neutron fluxes were essentially higher in comparison to those measured on Armenian airliners. It is interesting to note, that the neutron flux and equivalent dose rate decrease with altitude up to 470 km in space, for example, on board the STS-57. The shape of the differential energy spectrum for fast neutrons is the same on all Armenian airlines flights, but significantly different at 17 km altitude, where the flux in the energy region above 3 MeV is increasing.

  15. Individual monitoring of external exposure in terms of personal dose equivalent, Hp(d)

    International Nuclear Information System (INIS)

    Fantuzzi, E.

    2001-01-01

    The institute for Radiation Protection of ENEA - Bologna has organised a one day-workshop on the subject: Individual monitoring of external exposure in terms of personal dose equivalent, H p (d). The aim of the workshop was the discussion of the new implications and modifications to be expected in the routine individual monitoring of external radiation, due to the issue of the Decree 241/00 (G.U. 31/8/2000) in charge since 01/01/2001. The decree set up in Italian law the standards contained in the European Directive EURATOM 96/29-Basic Standards for the Protection of Health of Workers and the General Public against Dangers arising from Ionizing Radiation. Among others, the definition of the operational quantities for external radiation for personal and environmental monitoring, H p (d) e H * (d) respectively as defined by ICRU (International Commission for Radiation Units and Measurements), requires to update the methods of measurements and calibration of the personal dosemeters and environmental monitors. This report collects the papers presented at the workshop dealing with the Personal Dose Equivalent, H p (d), the conversion coefficients, H p (d)/K a e H p (d)/ , obtained through Monte Carlo calculations published by ICRU and ICRP (International Commission for Radiation Protection), the new calibration procedures and the practical implication in the routine of individual monitoring in terms of H p (d). Eventually, in the last chapter, the answers to Frequently Asked Questions (FAQ) are briefly reported [it

  16. The monetary value of the collective dose equivalent unit (person-rem)

    International Nuclear Information System (INIS)

    Rodgers, Reginald C.

    1978-01-01

    In the design and operation of nuclear power reactor facilities, it is recommended that radiation exposures to the workers and the general public be kept as 'low as reasonably achievable' (ALARA). In the process of implementing this principle cost-benefit evaluations are part of the decision making process. For this reason a monetary value has to be assigned to the collective dose equivalent unit (person-rem). The various factors such as medical health care, societal penalty and manpower replacement/saving are essential ingredients to determine a monetary value for the person-rem. These factors and their dependence on the level of risk (or exposure level) are evaluated. Monetary values of well under $100 are determined for the public dose equivalent unit. The occupational worker person-rem value is determined to be in the range of $500 to about $5000 depending on the exposure level and the type of worker and his affiliation, i.e., temporary or permanent. A discussion of the variability and the range of the monetary values will be presented. (author)

  17. The equivalent doses of indoor radon in some dwellings and enclosed areas in Morocco

    International Nuclear Information System (INIS)

    Hakam, O.; Choukri, J.; Reyss, L.

    2008-01-01

    Full text: The principal source of exposure to radiation for public in built-up areas is known to be the inhalation for radon its short-lived daughters.Most of this exposure occurs inside homes,where many hours are spent each day and where the volumic activity of radon is usually higher than outdoors. The compelling effects of radon and its short-lived decay products spread slowly but surely through a wide range of biological problems encountered in such areas as the mortality rates and lung cancer in uranium mines,the results of experimental work with animals, and the discovery of unsually high levels of radon in the living environments of the general population. As a way of prevention, we have measured the volumic activities of indoor radon-222 and we have calculated their effective equivalent dose in some dwellings and enclosed areas in Morocco. The obtained results show that the effective equivalent dose of activities measured indoor dwellings are inferior to the admissible annual limit fixed by ICRP for population, except in two twons situated in regions rich in phosphate deposits where the calculated doses are slightly upper than this limit. The results obtained for enclosed areas are inferior to the admissible annual limit fixed by ICRP for workers, except in the cave of geophysical observatory situated at depth of-12 meters where the obtained value don't present in risk for workers health because workers pass only a few minutes by day in this cave. The risks related to the volumic activities for indoor radon could be avoided by simple precautions such the continuous ventilation

  18. Total external dose equivalent and effective dose derived to the Piedmont population in the period 30 Apr 1986 - 22 Sep 1987

    International Nuclear Information System (INIS)

    Cortissone, C.; Giacomelli, R.; Spezzano, P.; Porzio, L.

    1988-01-01

    Some dosimetric evaluations concerning the population of the Piemonte Region, obtained after the measurements made following the Chernobyl accident, are reported. The individual effective mean dose equivalent derived from the exposure and intake in the period April 30, 1986 - September 22, 1987, is about 0.50 mSv

  19. SOILD: A computer model for calculating the effective dose equivalent from external exposure to distributed gamma sources in soil

    International Nuclear Information System (INIS)

    Chen, S.Y.; LePoire, D.; Yu, C.; Schafetz, S.; Mehta, P.

    1991-01-01

    The SOLID computer model was developed for calculating the effective dose equivalent from external exposure to distributed gamma sources in soil. It is designed to assess external doses under various exposure scenarios that may be encountered in environmental restoration programs. The models four major functional features address (1) dose versus source depth in soil, (2) shielding of clean cover soil, (3) area of contamination, and (4) nonuniform distribution of sources. The model is also capable of adjusting doses when there are variations in soil densities for both source and cover soils. The model is supported by a data base of approximately 500 radionuclides. 4 refs

  20. Medical irradiation and the use of the ''effective dose equivalent'' concept

    International Nuclear Information System (INIS)

    Persson, B.R.R.

    1980-01-01

    The aim of this paper is to demonstrate the use of the effective dose for all kinds of medical irradiation. In order to estimate the 'somatic effective dose' the weighting factors recommended by ICRP 26 have been separated into those for somatic effects and for genetic effects. Calculation of the effective dose in diagnostic radiology procedures must consider the various technical parameters which determine the absorbed dose in the various organs, i.e. beam quality, typical entrance dose and the number of films of each view. Knowledge about these parameters is not always well established and therefore the effective dose estimates are very uncertain. The average dose absorbed by various organs in the case of administration of radionuclides to the body depends to a much higher degree on biological parameters than in the case of external irradiation. In contrast to the variability and lack of reliability of biological data, the physical methods for internal dose calculation are quite elaborate. However, these methods have to be extended to involve the target dose from the radioactivity distributed within the remaining parts of the body. An attempt was made to estimate the somatic effective dose for the most common diagnostic X-ray and nuclear medicine procedures. This would make it possible to compare the risk of X-ray and nuclear medicine techniques on a more equitable basis. The collective effective dose from medical irradiation is estimated for various countries on the basis of reported statistical data. (H.K.)

  1. Conversion coefficients from air kerma to personal dose equivalent in mammography

    Energy Technology Data Exchange (ETDEWEB)

    Kuenzel, R., E-mail: roselikunzel@gmail.co [Area de Ciencias Naturais e Tecnologicas, Centro Universitario Franciscano, Rua dos Andradas 1614, 97010-032 Santa Maria, RS (Brazil); Levenhagen, R.S. [Universidade Nove de Julho, Av. Dr. Adolfo Pinto, 109, Barra Funda, 01156-050 Sao Paulo (Brazil); Herdade, S.B. [Secao Tecnica de Desenvolvimento Tecnologico em Saude, Instituto de Eletrotecnica e Energia, Universidade de Sao Paulo, Avenida Professor Luciano Gualberto, 1289, Cidade Universitaria, CEP 05508-010 Sao Paulo (Brazil)

    2010-05-15

    In this work, the scattered X-ray beams produced by a mammography unit with a Mo/Mo, Mo/Rh and W/Rh anode/filter combinations were applied in the evaluation of the H{sub p}(10,0{sup 0}) and mean conversion coefficients from air kerma to the personal dose equivalent (C-bar{sub H{sub p(10,0{sup 0})}}). The higher values of H{sub p}(10,0{sup 0}) are related to the Mo/Rh combination whereas the lower ones are for the W/Rh target/filter. C-bar{sub H{sub p(10,0{sup 0})}} values are in the range 0.19-0.54 Sv/Gy, where the higher values comprise the W/Rh combination.

  2. Dose-equivalent response CR-39 track detector for personnel neutron dosimetry

    International Nuclear Information System (INIS)

    Oda, K.; Ito, M.; Yoneda, H.; Miyake, H.; Yamamoto, J.; Tsuruta, T.

    1991-01-01

    A dose-equivalent response detector based on CR-39 has been designed to be applied for personnel neutron dosimetry. The intrinsic detection efficiency of bare CR-39 was first evaluated from irradiation experiments with monoenergetic neutrons and theoretical calculations. In the second step, the radiator effect was investigated for the purpose of sensitization to fast neutrons. A two-layer radiator consisting of deuterized dotriacontane (C 32 D 66 ) and polyethylene (CH 2 ) was designed. Finally, we made the CR-39 detector sensitive to thermal neutrons by doping with orthocarbone (B 10 H 12 C 2 ), and also estimated the contribution of albedo neutrons. It was found that the new detector - boron-doped CR-39 with the two-layer radiator - would have a flat response with an error of about 70% in a wide energy region, ranging from thermal to 15 MeV. (orig.)

  3. Effective Dose Equivalent To The Cypriot Population Due To Natural Radiation

    International Nuclear Information System (INIS)

    Christofides, S.

    1994-01-01

    A study was initiated by the Biomedical Research Foundation, two years ago, to estimate the various natural radiation components that contribute to the Effective Dose Equivalent (EDE) to the Cypriot population. The present study has shown that the contribution due to cosmic radiation is estimated to be less than 270 microSiverts per annum, while that due to airborne Rn-222 concentration in Cypriot houses is estimated to be less then 330 microSieverts per annum. The contribution due to terrestrial gamma radiations, which is currently under investigation, is so far estimated to be around 108 microSieverts per annum. Therefore the EDE to the Cypriot population due to natural radiation is likely to be around 700 microSieverts per annum, not taking into account the internal exposure due to other naturally occuring radionuclides. (author)

  4. The equivalent dose comparison of different grain size quartz from lakeshore sediments in the arid region

    International Nuclear Information System (INIS)

    Fan Yuxin; Chen Fahu; Zhao Hui

    2009-01-01

    To investigate the feasibility of OSL dating of lakeshore sediments, equivalent dose (D e ) values of quartz fractions in different grain-size were measured using the 'Double-SAR' protocol of optical dating in four lakeshore sediments. There are two obvious different relations between D e values and grain sizes. The first situation is that the D e values are accordant with each other for fractions between 63 μm and 400 μm with a slightly decreasing tread of D e values as increasing of grain-size. The second situation is that the D e values are accordant to each other for fractions between 125 μm and 300 μm, while the D e values of the 63-90 μm fraction are obviously smaller than others. The first is consistent with those reported elsewhere, while the second can't be understood by the previous theory. (authors)

  5. Investigation of real tissue water equivalent path lengths using an efficient dose extinction method

    Science.gov (United States)

    Zhang, Rongxiao; Baer, Esther; Jee, Kyung-Wook; Sharp, Gregory C.; Flanz, Jay; Lu, Hsiao-Ming

    2017-07-01

    For proton therapy, an accurate conversion of CT HU to relative stopping power (RSP) is essential. Validation of the conversion based on real tissue samples is more direct than the current practice solely based on tissue substitutes and can potentially address variations over the population. Based on a novel dose extinction method, we measured water equivalent path lengths (WEPL) on animal tissue samples to evaluate the accuracy of CT HU to RSP conversion and potential variations over a population. A broad proton beam delivered a spread out Bragg peak to the samples sandwiched between a water tank and a 2D ion-chamber detector. WEPLs of the samples were determined from the transmission dose profiles measured as a function of the water level in the tank. Tissue substitute inserts and Lucite blocks with known WEPLs were used to validate the accuracy. A large number of real tissue samples were measured. Variations of WEPL over different batches of tissue samples were also investigated. The measured WEPLs were compared with those computed from CT scans with the Stoichiometric calibration method. WEPLs were determined within  ±0.5% percentage deviation (% std/mean) and  ±0.5% error for most of the tissue surrogate inserts and the calibration blocks. For biological tissue samples, percentage deviations were within  ±0.3%. No considerable difference (extinction measurement took around 5 min to produce ~1000 WEPL values to be compared with calculations. This dose extinction system measures WEPL efficiently and accurately, which allows the validation of CT HU to RSP conversions based on the WEPL measured for a large number of samples and real tissues.

  6. Optimal use of β-blockers in high-risk hypertension: A guide to dosing equivalence

    Directory of Open Access Journals (Sweden)

    Janet B McGill

    2010-05-01

    Full Text Available Janet B McGillDepartment of Medicine, Washington University School of Medicine, St. Louis, Missouri, USAAbstract: Hypertension is the number one diagnosis made by primary care physicians, placing them in a unique position to prescribe the antihypertensive agent best suited to the individual patient. In individuals with diabetes mellitus, blood pressure (BP levels > 130/80 mmHg confer an even higher risk for cardiovascular and renal disease, and these patients will benefit from aggressive antihypertensive treatment using a combination of agents. β‑blockers are playing an increasingly important role in the management of hypertension in high-risk patients. β‑blockers are a heterogeneous class of agents, and this review presents the differences between β‑blockers and provides evidence-based protocols to assist in understanding dose equivalence in the selection of an optimal regimen in patients with complex needs. The clinical benefits provided by β‑blockers are only effective if patients adhere to medication treatment long term. β‑blockers with proven efficacy, once-daily dosing, and lower side effect profiles may become instrumental in the treatment of hypertensive diabetic and nondiabetic patients.Keywords: antihypertensive, blood pressure, atenolol, carvedilol, labetalol, metoprolol, nebivolol

  7. Study of response of radiation monitors for environmental dose equivalent measurements

    International Nuclear Information System (INIS)

    Souza, Macilene N.; Khoury, H.J.

    2005-01-01

    The environmental dose equivalent H * (10), is the magnitude recommended by ICRU 39 for environmental monitoring in fields of radiation of photons. Most of the equipment used for area monitoring, only quantifies the magnitudes exposure or dose not being designed to this new magnitude. In Brazil, particularly, is not yet regulated the use of H * (10). However, with the revision of the standard 3.01 it will necessary the use of monitors that allow the achievement of measures according to H * (10). The transition for using new magnitudes will be a slow process and the contribution that the laboratories of metrology of ionizing radiation in the country can give is, at first, promote and create the habit of using the unit Sievert (Sv) in the calibration of the instruments, and that is the unit recommended for H * (10). In a second step, the tests for determining the response of the instruments for H * (10) should be made and this is the harder step, taking into account the large number of area monitors around the country. These tests will provide information about the limitations of the instrument to the new magnitude, that is, the range where the instrument will have the best performance in quantification of new magnitude. This paper evaluates the performance for H * (10), with the variation of energy and angle of incidence of radiation, of three of the most used monitors in the country

  8. Derivation of a reference dose and drinking water equivalent level for 1,2,3-trichloropropane.

    Science.gov (United States)

    Tardiff, Robert G; Carson, M Leigh

    2010-06-01

    In some US potable water supplies, 1,2,3-trichloropropane (TCP) has been present at ranges of non-detect to less than 100 ppb, resulting from past uses. In subchronic oral studies, TCP produced toxicity in kidneys, liver, and other tissues. TCP administered by corn oil gavage in chronic studies produced tumors at multiple sites in rats and mice; however, interpretation of these studies was impeded by substantial premature mortality. Drinking water equivalent levels (DWELs) were estimated for a lifetime of consumption by applying biologically-based safety/risk assessment approaches, including Monte Carlo techniques, and with consideration of kinetics and modes of action, to possibly replace default assumptions. Internationally recognized Frameworks for human relevance of animal data were employed to interpret the findings. Calculated were a reference dose (=39 microg/kg d) for non-cancer and Cancer Values (CV) (=10-14 microg/kg d) based on non-linear dose-response relationships for mutagenicity as a precursor of cancer. Lifetime Average Daily Intakes (LADI) are 3130 and 790-1120 microg/person-d for non-cancer and cancer, respectively. DWELs, estimated by applying a relative source contribution (RSC) of 50% to the LADIs, are 780 and 200-280 microg/L for non-cancer and cancer, respectively. These DWELs may inform establishment of formal/informal guidelines and standards to protect public health. Copyright 2010 Elsevier Ltd. All rights reserved.

  9. Comparison of diagnostic protocols and the equivalent effective dose in renal cancer and herniated lumbar disc

    International Nuclear Information System (INIS)

    Ruiz Perez de Villar, M.J.; Vano Carruana, E.; Lanzos Gonbzalez, E.; Perez Torrubia, A.

    1994-01-01

    Renal cancer (RC) and herniated lumbar disc (HLD) were the two pathologies selected for the study of the diagnostic protocols applied in different centers to determine how their variability is reflected in the effective equivalent dose (EED) and establish the optimal radiological protocol for diagnostic purposes, while using the lowest possible dose. On the basis of 222 case histories, it was observed that the EED resulting from the diagnosis of HLD can vary as much as a factor of 3(6.2-18.9 mSv). Likewise, the EED related to the diagnosis of RC can be modified by a factor of 1.5(32.6-48.3 mSv), depending on the diagnostic protocol employed. It can be considered that the optimal protocol to reach a diagnosis of HLD includes chest x-ray, lumbar spine x-ray and lumbar CT scan, while that required for the diagnosis of RC involves chest x-ray, IVU, abdominal CT scan and digital subtraction angiography. The optimization of the study protocols-especially the reduction of the number of exposures, modernization and quality control of the equipment, among other aspects, can reduce the EED by a factor of 2. (Author)

  10. Method to determine the position-dependant metal correction factor for dose-rate equivalent laser testing of semiconductor devices

    Science.gov (United States)

    Horn, Kevin M.

    2013-07-09

    A method reconstructs the charge collection from regions beneath opaque metallization of a semiconductor device, as determined from focused laser charge collection response images, and thereby derives a dose-rate dependent correction factor for subsequent broad-area, dose-rate equivalent, laser measurements. The position- and dose-rate dependencies of the charge-collection magnitude of the device are determined empirically and can be combined with a digital reconstruction methodology to derive an accurate metal-correction factor that permits subsequent absolute dose-rate response measurements to be derived from laser measurements alone. Broad-area laser dose-rate testing can thereby be used to accurately determine the peak transient current, dose-rate response of semiconductor devices to penetrating electron, gamma- and x-ray irradiation.

  11. Effective doses in the radial gamma radiation field near a point source: gender difference and deviation from the personal dose equivalent

    International Nuclear Information System (INIS)

    Chang, Jai Kwon; Lee, Jai Ki

    1997-01-01

    The individual dose equivalent, H p , effective dose, E, and gender specific effective dose, E m , and E f , were evaluated using the male and female phantoms of MIRD type located in the radial gamma radiation field near a point source. The point sources were placed at the distances of 15, 40 and 100 cm in front of the body at different heights. Two radionuclides, 137 Cs and 131 I, were selected for the illustrative examples. In terms of the gender specific effective doses, E f is higher than E m with a few exceptions, e.g. the case where the point source is at the height of reproductive organs, but the differences from the sex- averaged values are not significant enough to justify use of gender specific dose conversion factors for the radial gamma field. The ratios H p /E were in the range of 1 to 3 depending on the source and dosimeter positions when the dosimeter is worn on the front surface of the torso covering from chest to lower abdomen, but varied from 0.34 to 6.5 in extreme cases. When it is assumed that the typical handling procedure of radioactive source material and the typical dosimeter position (on the chest) be respected, the dosimeters calibrated against the broad parallel field appear to provide estimates with acceptable errors for the effective dose of workers exposed to radial broad gamma field around a point source

  12. The distribution of committed dose equivalents to workers exposed to tritium in the luminising industry in the United Kingdom

    International Nuclear Information System (INIS)

    Hipkin, J.

    1977-01-01

    In the United Kingdom tritium has become almost the only radionuclide that is used in luminising. Two distinct methods of luminising are used, one involving the use of tritium gas and the other involving the use of tritium activated luminous paint. All major luminisers have voluntarily taken part in urine monitoring programmes. The analyses have been carried out by the National Radiological Protection Board and estimates of committed dose equivalent have been made from the results. The work presented is an analysis of the committed dose equivalents received by all the individuals monitored in the years 1974, 1975 and 1976. It is shown that doses follow, in general, a lognormal distribution modified only at the high dose end by what must be described as dose management. Further evidence for dose management is seen when the pattern of dose versus time are analysed for selected individuals. It is shown that the maximum permissible dose as recommended by the International Commission on Radiological Protection, is only rarely exceeded. It is also shown that there is a substantial difference in the degree of exposure between workers involved in gaseous tritium luminising and workers using paint luminising. A comparison is made between exposure in gaseous tritium luminising and exposure in another common use of gaseous tritium, ie. the filling of electronic devices with tritium gas. It is shown that exposure is very much less in the electronic device work

  13. Study of the equivalent dose distribution in organs and tissues using periapical odontological radiography

    International Nuclear Information System (INIS)

    Santos, H.F.S.; Cipeli, J.F.; Fortes, M.A.B.; Federico, C.A.

    2017-01-01

    In this article presents a study of the doses obtained in periapical odontological radiography in main tissues of the head, using thermoluminescent dosemeters of type TLD-700H applied to a anthropomorphic simulator. The results indicate that the skin and salivary glands received the highest doses and the risk of calculated injury was 1.44 x 10 -6 Sv -1 per radiograph

  14. Additional annual collective effective dose equivalent for population living in buildings of stone-like coal cinder materials

    International Nuclear Information System (INIS)

    Li Suyun

    1989-01-01

    A rough estimation of the additional annual collective effective dose equivalent was given for population living in buildings made of stone-like coal cinder bricks. The mean equilibrium-equivalent radon concentration was found to be 84 Bq/m 3 higher, and absorbed dose rate of gamma radiation 48.0 x 10 -8 Gy/h more, than that in control houses. The annual collective effective dose equivalent for population living in buildings of stone-like coal cinder bricks produced during one year was estimated to be 278.87 person-severt (with using a retention factor of 0.8) or 272.63 person-severt (with using a retention factor of 0.65)

  15. A Comparison of Equivalent Doses of Lidocaine and Articaine in Maxillary Posterior Tooth Extractions: Case Series

    Directory of Open Access Journals (Sweden)

    Christopher C. Friedl

    2012-06-01

    Full Text Available Objectives: Local anaesthesia is the standard of care during dental extractions. With the advent of newer local anesthetic agents, it is often difficult for the clinician to decide which agent would be most efficacious in a given clinical scenario. This study assessed the efficacy of equal-milligram doses of lidocaine and articaine in achieving surgical anaesthesia of maxillary posterior teeth diagnosed with irreversible pulpitis. Material and Methods: This case-series evaluated a total of 41 patients diagnosed with irreversible pulpitis in a maxillary posterior tooth. Patients randomly received an infiltration of either 3.6 mL (72 mg 2% lidocaine with 1:100,000 epinephrine or 1.8 mL (72 mg 4% articaine with 1:100,000 epinephrine in the buccal fold and palatal soft tissue adjacent to the tooth. After 10 minutes, initial anaesthesia of the tooth was assessed by introducing a sterile 27-gauge needle into the gingival tissue adjacent to the tooth, followed by relief of the gingival cuff. Successful treatment was considered to have occurred when the tooth was extracted with no reported pain. Data was analyzed with the Fisher’s exact test, unpaired t-test and normality test. Results: Twenty-one patients received lidocaine and 20 received articaine. Forty of the 41 patients achieved initial anaesthesia 10 minutes after injection: 21 after lidocaine and 19 after articaine (P = 0.488. Pain-free extraction was accomplished in 33 patients: 19 after lidocaine and 14 after articaine buccal and palatal infiltrations (P = 0.226. Conclusions: There was no significant difference in efficacy between equivalent doses of lidocaine and articaine in the anaesthesia of maxillary posterior teeth with irreversible pulpitis.

  16. Calculated organ equivalent doses for individuals in a sitting posture above a contaminated ground and a PET imaging room.

    Science.gov (United States)

    Su, Lin; Han, Bin; Xu, X George

    2012-03-01

    In this paper, phantoms representing sitting postures were developed and implemented in the MCNPX code to perform dose calculations. For the ground contamination case, isotropic planar source of (137)Cs was used. The male sitting phantom received an effective dose rate of 37.73 nSv h(-1) for a contamination of 30 kBq m(-2). The gonadal equivalent dose of the male sitting phantom was 40 % larger than that from the standing phantom. For the positron emission tomography clinic, a point photon source with the energy of 511 keV was used. The gonadal equivalent dose of the male sitting phantom was 117 % larger than that for the standing phantom. For an 8-h day, the effective dose of the sitting phantom was 2.54 μSv for 550 MBq F-18. This study concludes that phantoms with realistic postures could and should be considered in organ equivalent dose calculations in certain environmental and medical dosimetry studies where accurate data are desired.

  17. Significance and principles of the calculation of the effective dose equivalent for radiological protection of personnel and patients

    International Nuclear Information System (INIS)

    Drexler, G.; Williams, G.

    1985-01-01

    The application of the effective dose equivalent, Hsub(E), concept for radiological protection assessments of occupationally exposed persons is justifiable by the practicability thus achieved with regard to the limiting principles. Nevertheless, it would be proper logic to further use as the basic limiting quantity the real physical dose equivalent of homogeneous whole-body exposure, and for inhomogeneous whole-body irradiation the Hsub(E) value, calculated by means of the concept of the effective dose equivalent. For then the required concepts, models and calculations would not be connected with a basic radiation protection quantity. Application of the effective dose equivalent for radiation protection assessments for patients is misleading and is not practical with regard to assessing an individual or collective radiation risk of patients. The quantity of expected harm would be better suited to this purpose. There is no need to express the radiation risk by a dose quantity, which means careless handling of good information. (orig./WU) [de

  18. Calculation of neutron fluence to dose equivalent conversion coefficients using GEANT4; Calculo de coeficientes de fluencia de neutrons para equivalente de dose individual utilizando o GEANT4

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Rosane M.; Santos, Denison de S.; Queiroz Filho, Pedro P. de; Mauricio, CLaudia L.P.; Silva, Livia K. da; Pessanha, Paula R., E-mail: rosanemribeiro@oi.com.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2014-07-01

    Fluence to dose equivalent conversion coefficients provide the basis for the calculation of area and personal monitors. Recently, the ICRP has started a revision of these coefficients, including new Monte Carlo codes for benchmarking. So far, little information is available about neutron transport below 10 MeV in tissue-equivalent (TE) material performed with Monte Carlo GEANT4 code. The objective of this work is to calculate neutron fluence to personal dose equivalent conversion coefficients, H{sub p} (10)/Φ, with GEANT4 code. The incidence of monoenergetic neutrons was simulated as an expanded and aligned field, with energies ranging between thermal neutrons to 10 MeV on the ICRU slab of dimension 30 x 30 x 15 cm{sup 3}, composed of 76.2% of oxygen, 10.1% of hydrogen, 11.1% of carbon and 2.6% of nitrogen. For all incident energy, a cylindrical sensitive volume is placed at a depth of 10 mm, in the largest surface of the slab (30 x 30 cm{sup 2}). Physic process are included for neutrons, photons and charged particles, and calculations are made for neutrons and secondary particles which reach the sensitive volume. Results obtained are thus compared with values published in ICRP 74. Neutron fluence in the sensitive volume was calculated for benchmarking. The Monte Carlo GEANT4 code was found to be appropriate to calculate neutron doses at energies below 10 MeV correctly. (author)

  19. Development of prediction system of dose equivalent rate around a package

    International Nuclear Information System (INIS)

    Nakao, Tetsuya; Minakami, Goro; Taniuchi, Hiroaki; Fujisawa, Kyosuke; Matsukawa, Yukio; Mimura, Shigemi.

    1993-01-01

    A new system is developed that can evaluate the radiation strength of the source in detail, on the basis of the irradiation history of each fuel assembly in a TN-12 or 12A package, and then to determine the best way to organize the assemblies in the package so that the dose equivalent rate around a package is kept to a minimum. This system for minimizing the danger of radiation for operators involved in packaging and transporting spent fuel was developed for personal computer use, to offer ease in handling and high adaptability. The data input is done in dialogue style, with a variety of check functions. In checks to verify the accuracy of the shielding calculation data in this system by comparing the calculated values with several kinds of measured values, the reliability of this new system has been shown to be very high. Since its high utility has been recognized, the system has already been put into use in actual transportation situations. (J.P.N.)

  20. Calculation of the individual effective dose equivalent in Italy following the Chernobyl accident

    International Nuclear Information System (INIS)

    Lotfi, M.; Mancioppi, S.; Piermattei, S.; Tommasino, L.; Azimi-Garakani, D.

    1991-01-01

    Estimates are presented here for the individual effective dose equivalents (EDE) from dietary intake of radiocaesium-contaminated food by the average Italian consumer in different age groups. Food items of consumption rate greater than 50kg/y were included in the food basket studies. In view of the pattern of food consumption in Italy, the radiocaesium concentrations of foodstuffs such as milk, milk products, bread, pasta, meat fruit, vegetables and babyfoods were measured between January 1987 and December 1988 inclusive. These measurements were carried out mainly by the environmental radioactivity laboratories in three administrative districts of Italy. The results show that the total individual EDE values received in 1987 from foodstuffs were around 175, 110 and 70 μSv/year for adults, children (up to 10 years old) and infants (up to one year old), respectively. The corresponding values for 1988 are about 15, 10 and 20 μSv/year, respectively. The EDE committed in the latter half relative to the first half of 1987 was a factor of 2.5 and 3 less for adults and children, respectively, and a factor of about 2 for infants. In 1988, no significant change was observed in EDE values during the year. (author)

  1. A computer program to calculate the committed dose equivalent after the inhalation of radioactivity

    International Nuclear Information System (INIS)

    Van der Woude, S.

    1989-03-01

    A growing number of people are, as part of their occupation, at risk of being exposed to radiation originating from sources inside their bodies. The quantification of this exposure is an important part of health physics. The International Commission on Radiological Protection (ICRP) developed a first-order kinetics compartmental model to determine the transport of radioactive material through the human body. The model and the parameters involved in its use, are discussed. A versatile computer program was developed to do the following after the in vivo measurement of either the organ- or whole-body activity: calculate the original amount of radioactive material which was inhaled (intake) by employing the ICRP compartmental model of the human body; compare this intake to calculated reference levels and state any action to be taken for the case under consideration; calculate the committed dose equivalent resulting from this intake. In the execution of the above-mentioned calculations, the computer program makes provision for different aerosol particle sizes and the effect of previous intakes. Model parameters can easily be changed to take the effects of, for instance, medical intervention into account. The computer program and the organization of the data in the input files are such that the computer program can be applied to any first-order kinetics compartmental model. The computer program can also conveniently be used for research on problems related to the application of the ICRP model. 18 refs., 25 figs., 5 tabs

  2. Mapping of isoexposure curves for evaluation of equivalent environmental doses for radiodiagnostic mobile equipment

    International Nuclear Information System (INIS)

    Bacelar, Alexandre; Andrade, Jose Rodrigo Mendes; Fischer, Andreia Caroline Fischer da Silveira; Accurso, Andre; Hoff, Gabriela

    2011-01-01

    This paper generates iso exposure curves in areas where the mobile radiodiagnostic equipment are used for evaluation of iso kerma map and the environment equivalent dose (H * (d)). It was used a Shimadzu mobile equipment and two Siemens, with non anthropomorphic scatter. The exposure was measured in a mesh of 4.20 x 4.20 square meter in steps of 30 cm, at half height from the scatterer. The calculation of H * (d) were estimated for a worker present in all the procedures in a period of 11 months, being considered 3.55 m As/examination and 44.5 procedures/month (adult UTI) and 3.16 m As/examination and 20.1 procedure/month (pediatric UTI), and 3.16 m As/examination and 20.1 procedure/month (pediatric UTI). It was observed that there exist points where the H * (d) was over the limit established for the free area inside the radius of 30 cm from the central beam of radiation in the case of pediatric UTI and 60 cm for adult UTI. The points localized 2.1 m from the center presented values lower than 25% of those limit

  3. Regional inter-comparison of measurements of personal dose equivalent Hp(10) using photon beams

    International Nuclear Information System (INIS)

    Bero, M.; Zahili, M.; Kharita, M.H.

    2012-11-01

    The overall objective is to verify performance and to improve the Individual Monitoring services (IMS). This can be achieved with the following specific objectives of the intercomparison:1. To assess the capabilities of the dosimetry services to measure the quantity H p (10) in photon (gamma and x-ray) fields. 2. To help the participating Member States in achieving sufficiently accurate dosimetry service and, if necessary, 3. To provide guidelines for improvements and not simply a test of the performance of the existing dosimetric service. Actually a significant improvement has been achieved by the participants in the accuracy of evaluating personal dose equivalent from 15% in the first phase to 5% in the second phase. Some participants used the results of the inter-comparison to verify the calibration and to improve their dosimetric procedures, but from the results it was clear that some participants need to a technical support especially in calibration and using their measuring system in the field of personal monitoring. The conclusion contains advises, solutions, propositions and evaluation for all situations which noticed during the intercomparison. (authors)

  4. Personal dose equivalent Hp(0.07) of medical personnel occupationally exposed to ionizing radiation during 2001-2011.

    Science.gov (United States)

    Papierz, Sylwia; Kacprzyk, Janusz; Kamiński, Zbigniew; Adamowicz, Małgorzata; Zmyślony, Marek

    2012-01-01

    The paper presents the results of the determinations of the personal dose equivalent Hp(0.07) received by medical employees of interventional radiology departments occupationally exposed to X and gamma rays in Poland in 2011, performed by the Nofer Institute of Occupational Medicine in Łódź. The results were compared with the data collected during the last decade. The dosimetric service provided for medical employees of interventional radiology departments occupationally exposed to ionizing radiation in terms of the personal dose equivalent Hp(0.07). In 2011, personal dosimetry Hp(0.07) determinations performed by the Nofer Institute of Occupational Medicine in Łódź covered 2017 workers employed in 159 medical laboratories. The determinations were performed using ring dosimeters equipped with thermoluminescence detectors according to the procedure accredited by the Polish Centre for Accreditation (document number AB 327). The determinations were carried out in one or two-month periods. Mean annual personal dose equivalent Hp(0.07) in 2011 was equal to 4.9 mSv (annual limit for Hp(0.07) is 500 mSv). The mean annual doses of Hp(0.07) varied from 7.6 mSv in 2001 to 5.6 mSv in 2010. In 2011, two cases of exceeding the annual dose limit of Hp(0.07) were reported. The results show that more than 95% of all examined annual doses did not exceed the level of 10 mSv. The comparison of the average annual doses and detailed distributions of the doses during the last few years suggests a stabilized level of occupational exposure and an acceptable level of radiological protection in interventional radiology departments monitored by NIOM in Łódź.

  5. Evaluation of equivalent doses in 18F PET/CT using the Monte Carlo method with MCNPX code

    International Nuclear Information System (INIS)

    Belinato, Walmir; Santos, William Souza; Perini, Ana Paula; Neves, Lucio Pereira; Souza, Divanizia N.

    2017-01-01

    The present work used the Monte Carlo method (MMC), specifically the Monte Carlo NParticle - MCNPX, to simulate the interaction of radiation involving photons and particles, such as positrons and electrons, with virtual adult anthropomorphic simulators on PET / CT scans and to determine absorbed and equivalent doses in adult male and female patients

  6. Incidence of late rectal bleeding in high-dose conformal radiotherapy of prostate cancer using equivalent uniform dose-based and dose-volume-based normal tissue complication probability models

    International Nuclear Information System (INIS)

    Soehn, Matthias; Yan Di; Liang Jian; Meldolesi, Elisa; Vargas, Carlos; Alber, Markus

    2007-01-01

    Purpose: Accurate modeling of rectal complications based on dose-volume histogram (DVH) data are necessary to allow safe dose escalation in radiotherapy of prostate cancer. We applied different equivalent uniform dose (EUD)-based and dose-volume-based normal tissue complication probability (NTCP) models to rectal wall DVHs and follow-up data for 319 prostate cancer patients to identify the dosimetric factors most predictive for Grade ≥ 2 rectal bleeding. Methods and Materials: Data for 319 patients treated at the William Beaumont Hospital with three-dimensional conformal radiotherapy (3D-CRT) under an adaptive radiotherapy protocol were used for this study. The following models were considered: (1) Lyman model and (2) logit-formula with DVH reduced to generalized EUD (3) serial reconstruction unit (RU) model (4) Poisson-EUD model, and (5) mean dose- and (6) cutoff dose-logistic regression model. The parameters and their confidence intervals were determined using maximum likelihood estimation. Results: Of the patients, 51 (16.0%) showed Grade 2 or higher bleeding. As assessed qualitatively and quantitatively, the Lyman- and Logit-EUD, serial RU, and Poisson-EUD model fitted the data very well. Rectal wall mean dose did not correlate to Grade 2 or higher bleeding. For the cutoff dose model, the volume receiving > 73.7 Gy showed most significant correlation to bleeding. However, this model fitted the data more poorly than the EUD-based models. Conclusions: Our study clearly confirms a volume effect for late rectal bleeding. This can be described very well by the EUD-like models, of which the serial RU- and Poisson-EUD model can describe the data with only two parameters. Dose-volume-based cutoff-dose models performed worse

  7. Evaluation of effective dose equivalent on student's practice on intra-oral dental radiography

    Energy Technology Data Exchange (ETDEWEB)

    Wada, Shin-ichi; Hayama, Kazuhide; Toyama, Michio; Takase, Hiroshi (Nippon Dental Univ., Tokyo (Japan))

    1991-12-01

    We tried to discuss the problems on radiological protection of students in the practice of technique of intra-oral radiography with use of classmates. This radiographic practice has been performed after the technical training use of 'DXTTR' as a preclinical training. The practice was performed as training to take peri-apical, bite-wing, occlusal and eccentric projections. The mean film numbers which were used to complete those technique were 56 films. In these practice, dosimetries were performed on six locations of the body surface of every student who was taken radiograms using thermoluminescent dosimeters (TLD). The measured locations were orbit, bilateral submandible, neck, chest and abdomen. The effective dose equivalent was estimated using weighting factors of International Comission on Radiological Protection (ICRP) pub. 26 and the values of tissue dose equivalent obtained by TLD measurements. The results showed that the mean value of dose equivalent of each part was 5.40 mSv at orbit, 5.06 mSv at submandible, 0.75 mSv at neck, 0.04 mSv at chest and 0.02 mSv at abdomen. The maximum value of effective equivalent dose was 17.03 mSv which was lower than the dose equivalent limit for workers (50 mSv/year) recommended by ICRP pub. 26. The mean value of effective dose equivalent was 2.36 mSv. ICRP recommended the radiation protection for students aged 18 years or over that the procedures for restricting exposure should be broadly similar to those for occupational exposure. So the results indicate that those training was considered to be controlled in some reasonable level. The mean value of risk was estimated to be 3.94 x 10{sup -5}. Because intra-oral radiographic training with use of classmates is performed under extreme non-uniform irradiation, the evaluation of effective dose equivalent was considered to be important to control this special educational exposure and useful for optimization of the educational programs of radiographic technical training

  8. Diagnostic accuracy of chest X-ray dose-equivalent CT for assessing calcified atherosclerotic burden of the thoracic aorta.

    Science.gov (United States)

    Messerli, Michael; Giannopoulos, Andreas A; Leschka, Sebastian; Warschkow, René; Wildermuth, Simon; Hechelhammer, Lukas; Bauer, Ralf W

    2017-12-01

    To determine the value of ultralow-dose chest CT for estimating the calcified atherosclerotic burden of the thoracic aorta using tin-filter CT and compare its diagnostic accuracy with chest direct radiography. A total of 106 patients from a prospective, IRB-approved single-centre study were included and underwent standard dose chest CT (1.7 ± 0.7 mSv) by clinical indication followed by ultralow-dose CT with 100 kV and spectral shaping by a tin filter (0.13 ± 0.01 mSv) to achieve chest X-ray equivalent dose in the same session. Two independent radiologists reviewed the CT images, rated image quality and estimated presence and extent of calcification of aortic valve, ascending aorta and aortic arch. Conventional radiographs were also reviewed for presence of aortic calcifications. The sensitivity of ultralow-dose CT for the detection of calcifications of the aortic valve, ascending aorta and aortic arch was 93.5, 96.2 and 96.2%, respectively, compared with standard dose CT. The sensitivity for the detection of thoracic aortic calcification was significantly lower on chest X-ray (52.3%) compared with ultralow-dose CT (p < 0.001). A reliable estimation of calcified atherosclerotic burden of the thoracic aorta can be achieved with modern tin-filter CT at dose values comparable to chest direct radiography. Advances in knowledge: Our findings suggest that ultralow-dose CT is an excellent tool for assessing the calcified atherosclerotic burden of the thoracic aorta with higher diagnostic accuracy than conventional chest radiography and importantly without the additional cost of increased radiation dose.

  9. Thermally assisted OSL application for equivalent dose estimation; comparison of multiple equivalent dose values as well as saturation levels determined by luminescence and ESR techniques for a sedimentary sample collected from a fault gouge

    Science.gov (United States)

    Şahiner, Eren; Meriç, Niyazi; Polymeris, George S.

    2017-02-01

    Equivalent dose estimation (De) constitutes the most important part of either trap-charge dating techniques or dosimetry applications. In the present work, multiple, independent equivalent dose estimation approaches were adopted, using both luminescence and ESR techniques; two different minerals were studied, namely quartz as well as feldspathic polymineral samples. The work is divided into three independent parts, depending on the type of signal employed. Firstly, different De estimation approaches were carried out on both polymineral and contaminated quartz, using single aliquot regenerative dose protocols employing conventional OSL and IRSL signals, acquired at different temperatures. Secondly, ESR equivalent dose estimations using the additive dose procedure both at room temperature and at 90 K were discussed. Lastly, for the first time in the literature, a single aliquot regenerative protocol employing a thermally assisted OSL signal originating from Very Deep Traps was applied for natural minerals. Rejection criteria such as recycling and recovery ratios are also presented. The SAR protocol, whenever applied, provided with compatible De estimations with great accuracy, independent on either the type of mineral or the stimulation temperature. Low temperature ESR signals resulting from Al and Ti centers indicate very large De values due to bleaching in-ability, associated with large uncertainty values. Additionally, dose saturation of different approaches was investigated. For the signal arising from Very Deep Traps in quartz saturation is extended almost by one order of magnitude. It is interesting that most of De values yielded using different luminescence signals agree with each other and ESR Ge center has very large D0 values. The results presented above highly support the argument that the stability and the initial ESR signal of the Ge center is highly sample-dependent, without any instability problems for the cases of quartz resulting from fault gouge.

  10. Out-of-Field Dose Equivalents Delivered by Passively Scattered Therapeutic Proton Beams for Clinically Relevant Field Configurations

    International Nuclear Information System (INIS)

    Wroe, Andrew; Clasie, Ben; Kooy, Hanne; Flanz, Jay; Schulte, Reinhard; Rosenfeld, Anatoly

    2009-01-01

    Purpose: Microdosimetric measurements were performed at Massachusetts General Hospital, Boston, MA, to assess the dose equivalent external to passively delivered proton fields for various clinical treatment scenarios. Methods and Materials: Treatment fields evaluated included a prostate cancer field, cranial and spinal medulloblastoma fields, ocular melanoma field, and a field for an intracranial stereotactic treatment. Measurements were completed with patient-specific configurations of clinically relevant treatment settings using a silicon-on-insulator microdosimeter placed on the surface of and at various depths within a homogeneous Lucite phantom. The dose equivalent and average quality factor were assessed as a function of both lateral displacement from the treatment field edge and distance downstream of the beam's distal edge. Results: Dose-equivalent value range was 8.3-0.3 mSv/Gy (2.5-60-cm lateral displacement) for a typical prostate cancer field, 10.8-0.58 mSv/Gy (2.5-40-cm lateral displacement) for the cranial medulloblastoma field, 2.5-0.58 mSv/Gy (5-20-cm lateral displacement) for the spinal medulloblastoma field, and 0.5-0.08 mSv/Gy (2.5-10-cm lateral displacement) for the ocular melanoma field. Measurements of external field dose equivalent for the stereotactic field case showed differences as high as 50% depending on the modality of beam collimation. Average quality factors derived from this work ranged from 2-7, with the value dependent on the position within the phantom in relation to the primary beam. Conclusions: This work provides a valuable and clinically relevant comparison of the external field dose equivalents for various passively scattered proton treatment fields

  11. Simulation studies on a prototype ionization chamber for measurement of personal dose equivalent, Hp(10)

    International Nuclear Information System (INIS)

    Cardoso, J.; Oliveira, C.; Carvalho, A.F.

    2005-01-01

    Full text: The Metrological Laboratory of lonizing Radiation and Radioactivity (LMRIR) of Nuclear and Technological Institute (ITN) has designed and constructed a prototype ionization chamber for direct measurement of the personal dose equivalent, H p (10), similar to the developed by the Physikalisch-Technische Bundesanstalt (PTB) and now commercialized by PTW. Tests already performed had shown that the behaviour of this chamber is very close to the PTB chamber, namely the energy dependence for the x-ray radiation qualities of the ISO 4037-1 narrow series N-30, N-40, N-60, N-80, N-100 and N-120 and also for gamma radiation of 137 Cs and 60 Co. However, the results obtained also show a high dependence on the energy for some incident radiation angles and a low magnitude of the electrical response of the ionization chamber. In order to try to optimize the performance of the chamber, namely to decrease the energy dependence and to improve the magnitude of the electrical response of the ionization chamber, the LMRIR initiated numerical simulation of this ionization chamber using a Monte-Carlo method for simulation of radiation transport using, in a first step, the MCNPX code. So, simulation studies of some physical parameters are been performed in order to optimize the response of the ionization chamber, namely the diameter of the central electrode of the ionization chamber, the thickness of the front wall of the ionization chamber, among others. Preliminary results show that probably the actual geometry of the ionization chamber is not yet the optimized configuration. The simulation study will carry on in order to find the optimum geometry. (author)

  12. A study of dose equivalent for the nurses in Hirosaki University Hospital

    International Nuclear Information System (INIS)

    Kon, Masanori; Abe, Katsumi

    2001-01-01

    The annual relationships in 1997-1999 between exposure dose of those nurses engaging in full-time radiological works and the number of patients subjected to radiological examinations were investigated in authors' hospital. The annual number of those patients was rather constant. Exposure was measured by film-, carrot- and ring-badges. Eight to nine nurses engaged in radiological examinations like CT, fluoroscopy, urinary tract fluoroscopy and angiography, and other 8 nurses, therapy with sealed 137 Cs and 192 Ir and unsealed 131 I as well. No significant changes in exposure dose were observed in the former group of nurses and in the latter. The dose decreased annually to the level of the former due to skill advancement. (K.H.)

  13. The risk equivalent of an exposure to-, versus a dose of radiation

    International Nuclear Information System (INIS)

    Bond, V.P.

    1986-01-01

    The long-term potential carcinogenic effects of low-level exposure (LLE) are addressed. The principal point discussed is linear, no-threshold dose-response curve. That the linear no-threshold, or proportional relationship is widely used is seen in the way in which the values for cancer risk coefficients are expressed - in terms of new cases, per million persons exposed, per year, per unit exposure or dose. This implies that the underlying relationship is proportional, i.e., ''linear, without threshold''. 12 refs., 9 figs., 1 tab

  14. Effective and equivalent doses for CT head examinations calculated using the voxelized phantoms MASH and FASH

    Science.gov (United States)

    Ferreira, C. C.; Folly, W. S. D.; Vieira, J. W.; Maia, A. F.

    2011-09-01

    The voxelized phantoms MASH and FASH have been used for calculating conversion coefficients (CCs) for a specific CT head examination performed in a specific Toshiba CT scanner. The X-ray spectrum was selected according to the concordance between the calculated C 100,c and measured C 100,c. For 120 kV, the X-raytbc code presented the smaller deviation, equal to -7.11%. Finally, effective doses calculated for the voxelized phantoms MASH and FASH were 6.1 and 4.5, respectively, smaller than the effective dose obtained though the European guidelines on quality criteria for computed tomography.

  15. The biologically equivalent dose BED - Is the approach for calculation of this factor really a reliable basis?

    International Nuclear Information System (INIS)

    Jensen, J.M.; Zimmermann, J.

    2000-01-01

    To predict the effect on tumours in radiotherapy, especially relating to irreversible effects, but also to realize the retrospective assessment the so called L-Q-model is relied on at present. Internal specific organ parameters, such as α, β, γ, T p , T k , and ρ, as well as external parameters, so as D, d, n, V, and V ref , were used for determination of the biologically equivalent dose BED. While the external parameters are determinable with small deviations, the internal parameters depend on biological varieties and dispersons: In some cases the lowest value is assumed to be Δ=±25%. This margin of error goes on to the biologically equivalent dose by means of the principle of superposition of errors. In some selected cases (lung, kidney, skin, rectum) these margins of error were calculated exemplarily. The input errors especially of the internal parameters cause a mean error Δ on the biologically equivalent dose and a dispersion of the single fraction dose d dependent on the organ taking into consideration, of approximately 8-30%. Hence it follows only a very critical and cautious application of those L-Q-algorithms in expert proceedings, and in radiotherapy more experienced based decisions are recommended, instead of acting only upon simple two-dimensional mechanistic ideas. (orig.) [de

  16. Toxicokinetics of Deltamethrin: Dosage Dependency, Vehicle Effects, and Low-Dose Age-Equivalent Dosimetry in Rats.

    Science.gov (United States)

    Mortuza, Tanzir; Chen, Chen; White, Catherine A; Cummings, Brian S; Muralidhara, Srinivasa; Gullick, Darren; Bruckner, James V

    2018-03-01

    There is increasing concern that infants and children may be at increased risk of neurological effects of pyrethroids, the most widely used class of insecticide. The objectives of this investigation were to (1) characterize the dose-dependent toxicokinetics (TK) of deltamethrin (DLM) for exposures ranging from environmentally relevant to acutely toxic; (2) determine the influence of an aqueous versus oil vehicle on oral absorption and bioavailability; and (3) determine whether DLM exhibits low-dose, age-equivalent internal dosimetry. Serial arterial plasma samples were obtained for 72 h from adult, male Sprague Dawley rats given 0.05-5.0 mg DLM/kg as an oral bolus in corn oil (CO). DLM exhibited linear, absorption rate-limited TK. Increases in maximum plasma concentration (Cmax) and AUC∘∞ were directly proportional to the dose. Oral bioavailability was quite limited. The vehicle and its volume had modest effect on the rate and extent of systemic absorption in adult rats. Postnatal day (PND) 15, 21, and 90 (adult) rats received 0.10, 0.25, or 0.50 mg DLM/kg orally in CO and were sacrificed periodically for plasma, brain, and liver collection. Age-dependent differences between PND 15 and 90 plasma Cmax and AUC∘24 values progressively diminished as the dose decreased, but there was a lack of low dose age equivalence in these brain and liver dosimeters. Other maturational factors may account for the lack of the low-dose age equivalence in brain and liver. This investigation provides support for the premise that the relatively low metabolic capacity of immature subjects may be adequate to effectively eliminate trace amounts of DLM and other pyrethroids from the plasma.

  17. Assessment of individual dose equivalents Hp(0.07) of medical staff occupationally exposed to ionizing radiation in 2012.

    Science.gov (United States)

    Papierz, Sylwia; Kamiński, Zbigniew; Adamowicz, Małgorzata; Zmyślony, Marek

    2014-01-01

    The paper presents the Nofer Institutes of Occupational Medicine in Łódź's results of the assessment of individual dose equivalents Hp(0.07) of medical staff exposed to X-rays in Poland in 2012. In addition, the collected data was analysed in terms of types of medical units performing medical procedures and the categorization of personnel. Dosimetric service was provided for medical staff of interventional radiology departments occupationally exposed to ionizing radiation in terms of individual dose equivalents Hp(0.07). In 2012, personal dosimetry Hp(0.07) determinations were performed by the Nofer Institute of Occupational Medicine in Łódź and covered 2044 employees from 174 health facilities. The determinations were performed using thermoluminescence dosimetry according to the procedure accredited by the Polish Centre for Accreditation (document number AB 327). The measurements were performed using ring-dosimeters in the periods of 1 or 2 months. Mean annual individual dose equivalent Hp(0.07) in 2012 was equal to 3.3 mSv (annual limit for Hp(0.07) is 500 mSv). The average value of annual individual dose equivalent Hp(0.07) decreased comparing to the previous year. In 2012, no single case of exceeding the annual limit for Hp(0.07) was reported. Data stored in the file indicates that more than 96% of all of the annual doses did not exceed the level of 10 mSv. The analysis of data on occupational exposure to ionizing radiation confirms a stable level of exposure and satisfactory radiological protection in interventional radiology facilities monitored by the Nofer Institute of Occupational Medicine in Łódź in Poland in 2012.

  18. Estimating Radiation Risk from Total Effective Dose Equivalent (TEDE) – ISCORS Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2003-01-01

    The Interagency Steering Committee on Radiation Standards (ISCORS) recently issued guidance on calculating radiation risk estimates from dose. An EH-41 Information Brief discussing the method and the ISCORS technical report, “A Method for Estimating Radiation Risk from TEDE,” are attached. Exposure-to-risk estimates have been tabulated in a 1999 report, Cancer Risk Coefficients for Environmental Exposure to Radionuclides, Federal Guidance Report No. 13. This report was distributed within DOE previously for limited review and comment and it is now available on the EH-41 web site: http://www.eh.doe.gov/oepa. Although the approach used in Federal Guidance Report # 13 is more appropriate for circumstances where a radiation risk assessment is required than the dose-to-risk approach in the attached report, it is applicable only when the intake of an inhaled or ingested radionuclide is known or the radionuclide concentration in air, water or on the ground is known. In many cases, doses (specifically the TEDE) are calculated directly from computer codes and estimates of the intake or radionuclide concentrations are not directly available. The attached document is intended to facilitate the estimation of risk in those situations where dose (TEDE) is calculated directly.

  19. Personal dose equivalent conversion coefficients for neutron fluence over the energy range of 20-250 MeV.

    Science.gov (United States)

    Olsher, R H; McLean, T D; Justus, A L; Devine, R T; Gadd, M S

    2010-03-01

    Monte Carlo simulations were performed to extend existing neutron personal dose equivalent fluence-to-dose conversion coefficients to an energy of 250 MeV. Presently, conversion coefficients, H(p,slab)(10,alpha)/Phi, are given by ICRP-74 and ICRU-57 for a range of angles of radiation incidence (alpha = 0, 15, 30, 45, 60 and 75 degrees ) in the energy range from thermal to 20 MeV. Standard practice has been to base operational dose quantity calculations 20 MeV. Both light and heavy ions (HIs) (carbon, nitrogen and oxygen recoil nuclei) were transported down to a lower energy limit (1 keV for light ions and 5 MeV for HIs). Track energy below the limit was assumed to be locally deposited. For neutron tracks slab phantom.

  20. An overview of equivalent doses in eye lens of occupational radiation workers in medical, industrial and nuclear areas

    International Nuclear Information System (INIS)

    Lima, A.R.; Silva, F.C.A. da; Hunt, J.G.

    2013-01-01

    Some epidemiological evidences were recently reviewed by the ICRP and it was suggested that, for the eye lens, the absorbed dose threshold for induction of late detriments is about 0.5 Gy. On this basis, on 2011, the ICRP has recommended changes to the occupational dose limit in planned exposure situations, reducing the eye lens dose equivalent limit of 150 mSv to 20 mSv per year, on average, during the period of 5 years, with exposure not exceeding 50 mSv in a single year. Following the ICRP recommendation, the Brazilian Commission of Nuclear Energy (CNEN) adopted immediately the new limit to the eyes lens. This study aimed to show an overview about the doses in eye lens of occupational radiation workers in situations of planned exposures in the medical, industrial and nuclear areas, emphasizing the greatest radiological risks applications. It was observed that there are some limitations, such as example, to use individual monitor calibrated on Hp(3), to assess the equivalent dose in the eye lens. This limitation obstructs some experimental studies and monitoring of the levels of radiation received in the eye lens of radiation workers. Recent studies have showed that the lenses of eyes monitoring of workers, mainly in the planned exposure, must be follow-up. However, such researches were obtained only in medical exposures, mainly in interventional medicine procedures. Studies with planned exposure on nuclear and industrial areas are really needed and will be very important due to the new recommended by ICRP dose limits. (author)

  1. Sensitivity analysis concerning dose equivalents associated with the disposal of radioactive wastes in deep geological formations

    International Nuclear Information System (INIS)

    Lewi, J.; Mejon-Goula, M.J.; Cernes, A.; Brun-Yaba, C.

    1989-11-01

    Even if dose calculations may be performed for nuclear waste repositories in deep geological formations, it is unavoidable that the credibility of the obtained results might be affected by huge incertitudes in connection in particular with a lack of precise knowledge of the different components of the performed evaluations (scenarios, models, parameters). In consequence, this paper presents the approach adopted at the CEA/IPSN for performing sensitivity analysis and some obtained results [fr

  2. Evaluation of the effective equivalent dose in the general public due to the discharge of uranium in groundwater

    International Nuclear Information System (INIS)

    Gordon, A.M.P.L.; Jacomino, V.M.F.

    1989-12-01

    Some facilities available at IPEN-CNEN/SP may discharge uranium in their liquid effluents. The uranium contents of these effluents are analyzed by photometry or fluorimetry, and according to the results obtained a decision is made, by the Environmental Monitoring Division, upon their discharge to the environment. In 1988 a total activity of 3.66x10 9 Bq of uranium was discharge in a volume of approximately 30 m 3 . The effective equivalent dose in the general public was evaluated by making a conservative assumption that all the liquid effluents containing uranium are discharged directly to the soil reaching the groundwater. The dose calculation was carried out by using a generic model which described the transport of radionuclides in the groundwater. In order to be conservative it was also assumed that the critical pathway is the direct in gestion of water through hypothetical wells around the Institute. Conservative assumptions were also made in the characterization of the local aquifer parameters such as vertical and longitudinal dispersivity, effective porosity of the soil, hydraulic conductivity etc., in roder to overestimate the effective equivalent dose. The result obtained, of 5.3x10 -10 mSv/a is far below the dose limit for the public adopted by the Radiological Protection Board. The derived limit for the discharge was also evaluated, using the same model, giving a result of 3.6x10 13 Bq/a. (author) [pt

  3. Neutron spectrometry and determination of neutron ambient dose equivalents in different LINAC radiotherapy rooms

    Energy Technology Data Exchange (ETDEWEB)

    Domingo, C., E-mail: carles.domingo@uab.ca [Grup de Fisica de les Radiacions, Departament de Fisica. Edifici C, Campus UAB, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Garcia-Fuste, M.J.; Morales, E.; Amgarou, K. [Grup de Fisica de les Radiacions, Departament de Fisica. Edifici C, Campus UAB, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Terron, J.A. [Servicio de Radiofisica, Hospital Universitario Virgen Macarena. E- 41009 Sevilla. Spain (Spain); Rosello, J.; Brualla, L. [ERESA, Avda. Tres Cruces s/n. E-46014 Valencia (Spain); Nunez, L. [Servicio de Radiofisica, Hospital. Puerta de Hierro. E-28222 Majadahonda (Spain); Colmenares, R. [Serv. de Oncologia Radioterapica, Hosp. Ramon y Cajal, E-28049 Madrid (Spain); Gomez, F. [Dpto. de Particulas. Univ. de Santiago. E-15782 Santiago de Compostela. Spain (Spain); Hartmann, G.H. [DKFZ E0400 Im Neuenheimer Feld 280. D-69120 Heidelberg (Germany) (Germany); Sanchez-Doblado, F. [Servicio de Radiofisica, Hospital Universitario Virgen Macarena. E- 41009 Sevilla. Spain (Spain); Dpto. de Fisiologia Medica y Biofisica. Universidad de Sevilla. E-41009 Sevilla. Spain (Spain); Fernandez, F. [Grup de Fisica de les Radiacions, Departament de Fisica. Edifici C, Campus UAB, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Consejo de Seguridad Nuclear, Justo Dorado 11 E-28040 Madrid (Spain)

    2010-12-15

    A project has been set up to study the effect on a radiotherapy patient of the neutrons produced around the LINAC accelerator head by photonuclear reactions induced by photons above {approx}8 MeV. These neutrons may reach directly the patient, or they may interact with the surrounding materials until they become thermalised, scattering all over the treatment room and affecting the patient as well, contributing to peripheral dose. Spectrometry was performed with a calibrated and validated set of Bonner spheres at a point located at 50 cm from the isocenter, as well as at the place where a digital device for measuring neutrons, based on the upset of SRAM memories induced by thermal neutrons, is located inside the treatment room. Exposures have taken place in six LINAC accelerators with different energies (from 15 to 23 MV) with the aim of relating the spectrometer measurements with the readings of the digital device under various exposure and room geometry conditions. The final purpose of the project is to be able to relate, under any given treatment condition and room geometry, the readings of this digital device to patient neutron effective dose and peripheral dose in organs of interest. This would allow inferring the probability of developing second malignancies as a consequence of the treatment. Results indicate that unit neutron fluence spectra at 50 cm from the isocenter do not depend on accelerator characteristics, while spectra at the place of the digital device are strongly influenced by the treatment room geometry.

  4. Development and use of a fifteen year-old equivalent mathematical phantom for internal dose calculations

    International Nuclear Information System (INIS)

    Jones, R.M.; Poston, J.W.; Hwang, J.L.; Jones, T.D.; Warner, G.G.

    1976-06-01

    The existence of a phantom based on anatomical data for the average fifteen-year-old provides for a proficient means of obtaining estimates of absorbed dose for children of that age. Dimensions representative of an average fifteen-year-old human, obtained from various biological and medical research, were transformed into a mathematical construct of idealized shapes of the exterior, skeletal system, and internal organs of a human. The idealization for an average adult presently in use by the International Commission on Radiological Protection was used as a basis for design. The mathematical equations describing the phantom were developed to be readily adaptable to present-day methods of dose estimation. Typical exposure situations in nuclear medicine have previously been modeled for existing phantoms. With no further development of the exposure model necessary, adaptation to the fifteen-year-old phantom demonstrated the utility of the design. Estimates of absorbed dose were obtained for the administration of two radiopharmaceuticals, /sup 99m/Tc-sulfur colloid and /sup 99m/Tc-DMSA

  5. Neutron spectrometry and determination of neutron ambient dose equivalents in different LINAC radiotherapy rooms

    International Nuclear Information System (INIS)

    Domingo, C.; Garcia-Fuste, M.J.; Morales, E.; Amgarou, K.; Terron, J.A.; Rosello, J.; Brualla, L.; Nunez, L.; Colmenares, R.; Gomez, F.; Hartmann, G.H.; Sanchez-Doblado, F.; Fernandez, F.

    2010-01-01

    A project has been set up to study the effect on a radiotherapy patient of the neutrons produced around the LINAC accelerator head by photonuclear reactions induced by photons above ∼8 MeV. These neutrons may reach directly the patient, or they may interact with the surrounding materials until they become thermalised, scattering all over the treatment room and affecting the patient as well, contributing to peripheral dose. Spectrometry was performed with a calibrated and validated set of Bonner spheres at a point located at 50 cm from the isocenter, as well as at the place where a digital device for measuring neutrons, based on the upset of SRAM memories induced by thermal neutrons, is located inside the treatment room. Exposures have taken place in six LINAC accelerators with different energies (from 15 to 23 MV) with the aim of relating the spectrometer measurements with the readings of the digital device under various exposure and room geometry conditions. The final purpose of the project is to be able to relate, under any given treatment condition and room geometry, the readings of this digital device to patient neutron effective dose and peripheral dose in organs of interest. This would allow inferring the probability of developing second malignancies as a consequence of the treatment. Results indicate that unit neutron fluence spectra at 50 cm from the isocenter do not depend on accelerator characteristics, while spectra at the place of the digital device are strongly influenced by the treatment room geometry.

  6. A point-kernel shielding code for calculations of neutron and secondary gamma-ray 1cm dose equivalents: PKN

    International Nuclear Information System (INIS)

    Kotegawa, Hiroshi; Tanaka, Shun-ichi

    1991-09-01

    A point-kernel integral technique code, PKN, and the related data library have been developed to calculate neutron and secondary gamma-ray dose equivalents in water, concrete and iron shields for neutron sources in 3-dimensional geometry. The comparison between calculational results of the present code and those of the 1-dimensional transport code ANISN = JR, and the 2-dimensional transport code DOT4.2 showed a sufficient accuracy, and the availability of the PKN code has been confirmed. (author)

  7. Comparison of Out-Of-Field Neutron Equivalent Doses in Scanning Carbon and Proton Therapies for Cranial Fields

    DEFF Research Database (Denmark)

    Athar, B.; Henker, K.; Jäkel, O.

    2010-01-01

    Purpose: The purpose of this analysis is to compare the secondary neutron lateral doses from scanning carbon and proton beam therapies. Method and Materials: We simulated secondary neutron doses for out-of-field organs in an 11-year old male patient. Scanned carbon and proton beams were simulated......, absorbed neutron doses to tonsils and pharynx close to the field-edge were found to be 5x10-4 mSv/GyE and 4x10-4 mSv/GyE, respectively. Whereas, neutron equivalent doses to tonsils and pharynx were estimated to be 0.57mSv/GyE and 0.55 mSv/GyE in scanned proton therapy, respectively. In heavy ion carbon...... beams neutrons produced inside the patient are emitted at small angles, predominantly in the forward direction, whereas in proton therapy, neutrons are emitted more isotropic. Therefore the absorbed neutron doses in carbon therapy lateral to the field edge are smaller compared to the corresponding...

  8. Evaluation of equivalent and effective dose by KAP for patient and orthopedic surgeon in vertebral compression fracture surgery

    International Nuclear Information System (INIS)

    Santos, Felipe A.; Galeano, Diego C.; Santos, William S.; Silva, Ademir X.; Souza, Susana O.; Carvalho Júnior, Albérico B.

    2017-01-01

    Clinical scenarios were virtually modeled to estimate both the equivalent and effective doses normalized by KAP (Kerma Area Product) to vertebra compression fracture surgery in patient and surgeon. This surgery is known as kyphoplasty and involves the use of X-ray equipment, the C-arm, which provides real-time images to assist the surgeon in conducting instruments inserted into the patient and in the delivery of surgical cement into the fractured vertebra. The radiation transport code used was MCNPX (Monte Carlo N-Particle eXtended) and a pair of UFHADM (University of Florida Hybrid ADult Male) virtual phantoms. The developed scenarios allowed us to calculate a set of equivalent dose (H T ) and effective dose (E) for patients and surgeons. In additional, the same scenario was calculated KAP in the tube output and was used for calculating conversion coefficients (E/KAP and H T /KAP). From the knowledge of the experimental values of KAP and the results presented in this study, it is possible to estimate absolute values of effective doses for different exposure conditions. In this work, we developed scenarios with and without the surgical table with the purpose of comparison with the existing data in the literature. The absence of the bed in the scenario promoted a percentage absolute difference of 56% in the patient effective doses in relation to scenarios calculated with a bed. Regarding the surgeon, the use of the personal protective equipment (PPE) reduces between 75% and 79% the effective dose and the use of the under table shield (UTS) reduces the effective dose of between 3% and 7%. All these variations emphasize the importance of the elaboration of virtual scenarios that approach the actual clinical conditions generating E/KAP and H T /KAP closer to the actual values. - Highlights: • Virtual scenarios of vertebra compression fracture surgery. • MC simulations using virtual anthropomorphic phantoms and surgical setups. • Estimation of E/KAP and H T /KAP

  9. Increased cortical porosity is associated with daily, not weekly, administration of equivalent doses of teriparatide.

    Science.gov (United States)

    Zebaze, Roger; Takao-Kawabata, Ryoko; Peng, Yu; Zadeh, Ali Ghasem; Hirano, Kyoko; Yamane, Hiroshi; Takakura, Aya; Isogai, Yukihiro; Ishizuya, Toshinori; Seeman, Ego

    2017-06-01

    The pharmacokinetic profile of parathyroid hormone (PTH) determines its effects on bone resorption and formation. When administered intermittently, anabolic effects are favored in comparison with the continuous treatment. Among the intermittent treatment regimens, lower frequency of administration may have a lower effect on bone remodeling. We therefore hypothesized that weekly administration of teriparatide will produce less increase in intracortical remodeling and porosity than reported using daily treatment. We treated 17 female New Zealand white rabbits aged 6months for 1month with teriparatide [human PTH(1-34)] as follows. (i) Vehicle-treated Control (n=4); (ii) 20μg/kg daily (n=3); (iii) 40μg/kg daily (n=3); (iv) 140μg/kg weekly (n=3); (v) 280μg/kg weekly (n=4). Proximal femurs were imaged ex vivo using micro-CT (Scanco Viva CT-40) at 15μmvoxel size. Areas, pore size, and porosity were analyzed on the total, compact cortex (CC), and transitional zones in a 10mm length region of interest (ROI) starting at the midshaft using StrAx1.0. Compared to controls, the 20μg/kg daily was associated with 3.0% higher porosity in the transitional zone (p=0.09) while the 40μg/kg daily was associated with a higher porosity in the cortex (8.7%; p=0.04) and in the transitional zone (5.7%; p=0.007). The daily regimens were also associated with a greater proportion of porosity due to pores >15μm 2 ; particularly in the transitional zone where 20 and 40μg/kg daily increased porosity 2 fold (p=0.06) and 5 fold (p=0.04) relative controls respectively. The 140 and 280μg/kg weekly were not associated with an increase in porosity. There was no difference in total, compact or transitional zone cross sectional areas between the groups. Effects of intermittent teriparatide depend on the dose and frequency of administration. Daily dosing, particularly the higher dose, but not weekly dosing, increased cortical porosity. Work is needed to investigate the effects of the regimens on

  10. Biological dose estimation

    African Journals Online (AJOL)

    a radiation. •. In exposure. Biological dose estimation involving low-dose. S. JANSEN, G. J. VAN HUYSSTEEN. Summary. Blood specimens were collected from 8 people 18 days after they had been accidentally exposed to a 947,2 GBq iridium-. 192 source during industrial application. The equivalent whole-body dose ...

  11. Semi-empirical equivalent field method for dose determination in midline block fields for cobalt - 60 beam

    International Nuclear Information System (INIS)

    Tagoe, S.N.A.; Nani, E.K.; Yarney, J.; Edusa, C.; Quayson-Sackey, K.; Nyamadi, K.M.; Sasu, E.

    2012-01-01

    For teletherapy treatment time calculations, midline block fields are resolved into two fields, but neglecting scattering from other fields, the effective equivalent square field size of the midline block is assumed to the resultant field. Such approach is underestimation, and may be detrimental in achieving the recommended uncertainty of ± 5 % for patient's radiation dose delivery. By comparison, the deviations of effective equivalent square field sizes by calculations and experiments were within 13.2 % for cobalt 60 beams of GWGP80 cobalt 60 teletherapy. Therefore, a modified method incorporating the scatter contributions was adopted to estimate the effective equivalent square field size for midline block field. The measured outputs of radiation beams with the block were compared with outputs of square fields without the blocks (only the block tray) at depths of 5 and 10 cm for the teletherapy machine employing isocentric technique, and the accuracy was within ± 3 % for the cobalt 60 beams. (au)

  12. Evaluation of dose equivalent to the people accompanying patients in diagnostic radiology using MCNP4C Monte Carlo code

    International Nuclear Information System (INIS)

    Mehdizadeh, S.; Faghihi, R.; Sina, S.; Zehtabian, M.

    2007-01-01

    Complete text of publication follows. Objective: X rays used in diagnostic radiology contribute a major share to population doses from man-made sources of radiation. In some branches of radiology, it is necessary that another person stay in the imaging room and immobilize the patient to carry out radiological operation. ICRP 70 recommends that this should be done by parents or accompanying nursing or ancillary personnel and not in any case by radiation workers. Methods: Dose measurements were made previously using standard methods employing LiF TLD-100 dosimeters. A TLD card was installed on the main trunk of the body of the accompanying people where the maximum dose was probable. In this research the general purpose Monte Carlo N-particle radiation transport computer code (MCNP4C) is used to calculate the equivalent dose to the people accompanying patients exposed to radiation scattered from the patient (Without protective clothing). To do the simulations, all components of the geometry are placed within an air-filled box. Two homogeneous water phantoms are used to simulate the patient and the accompanying person. The accompanying person leans against the table at one side of the patient. Finally in case of source specification, only the focus of the X-ray tube is modelled, i.e. as a standard MCNP point source emitting a cone of photons. Photon stopping material is used as a collimator model to reduce the circular cross section of the cone to a rectangle. The X-ray spectra to be used in the MCNP simulations are generated with spectrum generator software, taking the X-ray voltage and all filtration applied in the clinic as input parameters. These calculations are done for different patient sizes and for different radiological operations. Results: In case of TL dosimetry, for a group of 100 examinations, the dose equivalents ranged from 0.01 μsv to 0.13 msv with the average of 0.05 msv. The results are seen to be in close agreement with Monte Carlo simulations

  13. Using generalized equivalent uniform dose atlases to combine and analyze prospective dosimetric and radiation pneumonitis data from 2 non-small cell lung cancer dose escalation protocols.

    Science.gov (United States)

    Liu, Fan; Yorke, Ellen D; Belderbos, José S A; Borst, Gerben R; Rosenzweig, Kenneth E; Lebesque, Joos V; Jackson, Andrew

    2013-01-01

    To demonstrate the use of generalized equivalent uniform dose (gEUD) atlas for data pooling in radiation pneumonitis (RP) modeling, to determine the dependence of RP on gEUD, to study the consistency between data sets, and to verify the increased statistical power of the combination. Patients enrolled in prospective phase I/II dose escalation studies of radiation therapy of non-small cell lung cancer at Memorial Sloan-Kettering Cancer Center (MSKCC) (78 pts) and the Netherlands Cancer Institute (NKI) (86 pts) were included; 10 (13%) and 14 (17%) experienced RP requiring steroids (RPS) within 6 months after treatment. gEUD was calculated from dose-volume histograms. Atlases for each data set were created using 1-Gy steps from exact gEUDs and RPS data. The Lyman-Kutcher-Burman model was fit to the atlas and exact gEUD data. Heterogeneity and inconsistency statistics for the fitted parameters were computed. gEUD maps of the probability of RPS rate≥20% were plotted. The 2 data sets were homogeneous and consistent. The best fit values of the volume effect parameter a were small, with upper 95% confidence limit around 1.0 in the joint data. The likelihood profiles around the best fit a values were flat in all cases, making determination of the best fit a weak. All confidence intervals (CIs) were narrower in the joint than in the individual data sets. The minimum P value for correlations of gEUD with RPS in the joint data was .002, compared with P=.01 and .05 for MSKCC and NKI data sets, respectively. gEUD maps showed that at small a, RPS risk increases with gEUD. The atlas can be used to combine gEUD and RPS information from different institutions and model gEUD dependence of RPS. RPS has a large volume effect with the mean dose model barely included in the 95% CI. Data pooling increased statistical power. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Using Generalized Equivalent Uniform Dose Atlases to Combine and Analyze Prospective Dosimetric and Radiation Pneumonitis Data From 2 Non-Small Cell Lung Cancer Dose Escalation Protocols

    Energy Technology Data Exchange (ETDEWEB)

    Liu Fan; Yorke, Ellen D. [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Belderbos, Jose S.A.; Borst, Gerben R. [The Netherlands Cancer Institute, Antoni Van Leeuwenhoek Hospital, Amsterdam (Netherlands); Rosenzweig, Kenneth E. [Mount Sinai School of Medicine, New York, New York (United States); Lebesque, Joos V. [The Netherlands Cancer Institute, Antoni Van Leeuwenhoek Hospital, Amsterdam (Netherlands); Jackson, Andrew, E-mail: jacksona@mskcc.org [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    2013-01-01

    Purpose: To demonstrate the use of generalized equivalent uniform dose (gEUD) atlas for data pooling in radiation pneumonitis (RP) modeling, to determine the dependence of RP on gEUD, to study the consistency between data sets, and to verify the increased statistical power of the combination. Methods and Materials: Patients enrolled in prospective phase I/II dose escalation studies of radiation therapy of non-small cell lung cancer at Memorial Sloan-Kettering Cancer Center (MSKCC) (78 pts) and the Netherlands Cancer Institute (NKI) (86 pts) were included; 10 (13%) and 14 (17%) experienced RP requiring steroids (RPS) within 6 months after treatment. gEUD was calculated from dose-volume histograms. Atlases for each data set were created using 1-Gy steps from exact gEUDs and RPS data. The Lyman-Kutcher-Burman model was fit to the atlas and exact gEUD data. Heterogeneity and inconsistency statistics for the fitted parameters were computed. gEUD maps of the probability of RPS rate {>=}20% were plotted. Results: The 2 data sets were homogeneous and consistent. The best fit values of the volume effect parameter a were small, with upper 95% confidence limit around 1.0 in the joint data. The likelihood profiles around the best fit a values were flat in all cases, making determination of the best fit a weak. All confidence intervals (CIs) were narrower in the joint than in the individual data sets. The minimum P value for correlations of gEUD with RPS in the joint data was .002, compared with P=.01 and .05 for MSKCC and NKI data sets, respectively. gEUD maps showed that at small a, RPS risk increases with gEUD. Conclusions: The atlas can be used to combine gEUD and RPS information from different institutions and model gEUD dependence of RPS. RPS has a large volume effect with the mean dose model barely included in the 95% CI. Data pooling increased statistical power.

  15. The interpretation of quartz optically stimulated luminescence equivalent dose versus time plots

    International Nuclear Information System (INIS)

    Bailey, R.M.

    2000-01-01

    Numerical modelling has shown that the form of the quartz OSL shine plateau (hereafter 'D e (t)-plot') is influenced by the effects of phototransferred TL in the ∼110 deg. C region. It is suggested also that the presence of multiple OSL components (as described by Partial bleaching and the decay form characteristics of quartz OSL. Radiat. Meas., 27, 123-136. The form of the optically stimulated luminescence signal of quartz: implications of dating. Unpublished PhD thesis, University of London) affects the form of the D e (t)-plot. Laboratory measurements of a fully reset and artificially dosed sample yielded non-flat D e (t)-plots, the deviation being greater for the larger of the two simulated palaeodoses, in accordance with theoretical predictions. It is suggested that the so-called 'shine plateau' test is of limited use in assessing the bleaching history of quartz sediments

  16. Adoption of new ICRU operational magnitude for the measurement of equivalent doses in Guatemala

    International Nuclear Information System (INIS)

    Guillen, J.A.

    1996-01-01

    This papers compares the results using a dosimetric irradiation in free air under normal incidence and with an IAEA phantom of 30x30x30 in terms of new ICRU magnitudes for the dosimetric systems designed by the National Radiological Protection Board of the United Kingdom with a Kodak Monitoring film type 2. At the same time , this papers presents the characterization requisites and firsts essays as an angular and energy dependence that should be satisfied to establish the regulations for the personal dosimetry service. Finally, it concludes that the dosimetric systems used by the Nuclear Energy general Direction (DGEN) is available for the measurement of the new ICRU Hp and Hs amounts without any additional modifications to the manufacturing of the dosimeter and that users should be trained once again in interpreting body doses with the new philosophy of the ICRP 60

  17. Fluence to Dose Equivalent Conversion Coefficients for Evaluation of Accelerator Radiation Environments

    International Nuclear Information System (INIS)

    Thomas, Ralph H.; Zeman, Gary H.

    2001-01-01

    The derivation of a set of conversion functions for the expression of neutron fluence measurements in terms of Effective Dose, E, is described. Four functions in analytical form are presented, covering the neutron energy range from 2.5 10-8 to 10+4 MeV, for the interpretation of fluence measurements in the typical irradiation conditions experienced around high-energy proton accelerators such as the Bevatron. For neutron energies below 200 MeV the analytical functions were modeled after the ISO and ROT conversion coefficients in ICRU 57. For neutron energies above 200 MeV, the analytical function was derived from an analysis of recent published data. Sample calculations using either the analytical expressions or the tabulated conversion coefficients from which the analytical expressions are derived show agreement to better than plus/minus 5%

  18. Enjebi Island dose assessment

    International Nuclear Information System (INIS)

    Robison, W.L.; Conrado, C.L.; Phillips, W.A.

    1987-07-01

    We have updeated the radiological dose assessment for Enjebi Island at Enewetak Atoll using data derived from analysis of food crops grown on Enjebi. This is a much more precise assessment of potential doses to people resettling Enjebi Island than the 1980 assessment in which there were no data available from food crops on Enjebi. Details of the methods and data used to evaluate each exposure pathway are presented. The terrestrial food chain is the most significant potential exposure pathway and 137 Cs is the radionuclide responsible for most of the estimated dose over the next 50 y. The doses are calculated assuming a resettlement date of 1990. The average wholebody maximum annual estimated dose equivalent derived using our diet model is 166 mremy;the effective dose equivalent is 169 mremy. The estimated 30-, 50-, and 70-y integral whole-body dose equivalents are 3.5 rem, 5.1 rem, and 6.2 rem, respectively. Bone-marrow dose equivalents are only slightly higher than the whole-body estimates in each case. The bone-surface cells (endosteal cells) receive the highest dose, but they are a less sensitive cell population and are less sensitive to fatal cancer induction than whole body and bone marrow. The effective dose equivalents for 30, 50, and 70 y are 3.6 rem, 5.3 rem, and 6.6 rem, respectively. 79 refs., 17 figs., 24 tabs

  19. Didactic revision of the operative magnitudes system ICRU for the evaluation of the equivalent dose in radiation external fields

    International Nuclear Information System (INIS)

    Alvarez R, J. T.

    2014-10-01

    In this work is presented in a didactic way the operative magnitudes system ICRU, showing as these magnitudes carry out an appropriate estimate of the effective equivalent doses H E and the effective dose. The objective is to present the basic concepts of the dosimetry for radiation external fields with purposes of radiological protection, because the assimilation lack and technological development of this dosimetric magnitudes system has persisted for near 50 years, in terms of practice of the radiological protection in Mexico. Also, this system is an essential part of safety basic standards of the IAEA and ICRP recommendations 26, 60, 74 and 103, as well as of the ICRU 25, 39, 43, 51 and 57. (Author)

  20. A new Monte Carlo program for calculations of dose distributions within tissue equivalent phantoms irradiated from π--meson beams

    International Nuclear Information System (INIS)

    Przybilla, G.

    1980-11-01

    The present paper reports on the structure and first results from a new Monte Carlo programme for calculations of energy distributions within tissue equivalent phantoms irradiated from π - -beams. Each pion or generated secondary particle is transported until to the complete loss of its kinetic energy taking into account pion processes like multiple Coulomb scattering, pion reactions in flight and absorption of stopped pions. The code uses mainly data from experiments, and physical models have been added only in cases of lacking data. Depth dose curves for a pensil beam of 170 MeV/c within a water phantom are discussed as a function of various parameters. Isodose contours are plotted resulting from a convolution of an extended beam profile and the dose distribution of a pencil beams. (orig.) [de

  1. Measurement of conversion coefficients between air Kerma and personal dose equivalent and backscatter factors for diagnostic X-ray beams

    International Nuclear Information System (INIS)

    Rosado, Paulo Henrique Goncalves

    2008-01-01

    Two sets of quantities are import in radiological protection: the protection and operational quantities. Both sets can be related to basic physical quantities such as kerma through conversion coefficients. For diagnostic x-ray beams the conversion coefficients and backscatter factors have not been determined yet, those parameters are need for calibrating dosimeters that will be used to determine the personal dose equivalent or the entrance skin dose. Conversion coefficients between air kerma and personal dose equivalent and backscatter factors were experimentally determined for the diagnostic x-ray qualities RQR and RQA recommended by the International Electrotechnical Commission (IEC). The air kerma in the phantom and the mean energy of the spectrum were measured for such purpose. Harshaw LiF-100H thermoluminescent dosemeters (TLD) were used for measurements after being calibrated against an 180 cm 3 Radcal Corporation ionization chamber traceable to a reference laboratory. A 300 mm x 300 mm x 150 mm polymethylmethacrylate (PMMA) slab phantom was used for deep-dose measurements. Tl dosemeters were placed in the central axis of the x-ray beam at 5, 10, 15, 25 and 35 mm depth in the phantom upstream the beam direction Another required parameter for determining the conversion coefficients from was the mean energy of the x-ray spectrum. The spectroscopy of x-ray beams was done with a CdTe semiconductor detector that was calibrated with 133 Ba, 241 Am and 57 Co radiation sources. Measurements of the x-ray spectra were carried out for all RQR and RQA IEC qualities. Corrections due to the detector intrinsic efficiency, total energy absorption, escape fraction of the characteristic x-rays, Compton effect and attenuation in the detector were done aiming an the accurate determination of the mean energy. Measured x-ray spectra were corrected with the stripping method by using these response functions. The typical combined standard uncertainties of conversion coefficients and

  2. Using two detectors concurrently to monitor ambient dose equivalent rates in vehicle surveys of radiocesium contaminated land.

    Science.gov (United States)

    Takeishi, Minoru; Shibamichi, Masaru; Malins, Alex; Kurikami, Hiroshi; Murakami, Mitsuhiro; Saegusa, Jun; Yoneya, Masayuki

    2017-10-01

    In response to the accident at Tokyo Electric Power Company's Fukushima Dai-ichi Nuclear Power Plant (FDNPP), vehicle-borne monitoring was used to map radiation levels for radiological protection of the public. By convention measurements from vehicle-borne surveys are converted to the ambient dose equivalent rate at 1 m height in the absence of the vehicle. This allows for comparison with results from other types of survey, including surveys with hand-held or airborne instruments. To improve the accuracy of the converted results from vehicle-borne surveys, we investigated combining measurements from two detectors mounted on the vehicle at different heights above the ground. A dual-detector setup was added to a JAEA monitoring car and compared against hand-held survey meter measurements in Fukushima Prefecture. The results obtained by combining measurements from two detectors were within ±20% of the hand-held reference measurements. The mean absolute percentage deviation from the reference measurements was 7.2%. The combined results from the two detectors were more accurate than those from either the roof-mounted detector, or the detector inside the vehicle, taken alone. One issue with vehicle-borne surveys is that ambient dose equivalent rates above roads are not necessarily representative of adjacent areas. This is because radiocesium is often deficient on asphalt surfaces, as it is easily scrubbed off by rain, wind and vehicle tires. To tackle this issue, we investigated mounting heights for vehicle-borne detectors using Monte Carlo gamma-ray simulations. When radiocesium is deficient on a road compared to the adjacent land, mounting detectors high on vehicles yields results closer to the values adjacent to the road. The ratio of ambient dose equivalent rates reported by detectors mounted at different heights in a dual-detector setup indicates whether radiocesium is deficient on the road compared to the adjacent land. Copyright © 2017 Elsevier Ltd. All rights

  3. MOSFET dosimeter depth-dose measurements in heterogeneous tissue-equivalent phantoms at diagnostic x-ray energies

    International Nuclear Information System (INIS)

    Jones, A.K.; Pazik, F.D.; Hintenlang, D.E.; Bolch, W.E.

    2005-01-01

    The objective of the present study was to explore the use of the TN-1002RD metal-oxide-semiconductor field effect transistor (MOSFET) dosimeter for measuring tissue depth dose at diagnostic photon energies in both homogeneous and heterogeneous tissue-equivalent materials. Three cylindrical phantoms were constructed and utilized as a prelude to more complex measurements within tomographic physical phantoms of pediatric patients. Each cylindrical phantom was constructed as a stack of seven 5-cm-diameter and 1-cm-thick discs of materials radiographically representative of either soft tissue (S), bone (B), or lung tissue (L) at diagnostic photon energies. In addition to a homogeneous phantom of soft tissue (SSSSSSS), two heterogeneous phantoms were constructed: SSBBSSS and SBLLBSS. MOSFET dosimeters were then positioned at the interface of each disc, and the phantoms were then irradiated at 66 kVp and 200 mAs. Measured values of absorbed dose at depth were then compared to predicated values of point tissue dose as determined via Monte Carlo radiation transport modeling. At depths exceeding 2 cm, experimental results matched the computed values of dose with high accuracy regardless of the dosimeter orientation (epoxy bubble facing toward or away from the x-ray beam). Discrepancies were noted, however, between measured and calculated point doses near the surface of the phantom (surface to 2 cm depth) when the dosimeters were oriented with the epoxy bubble facing the x-ray beam. These discrepancies were largely eliminated when the dosimeters were placed with the flat side facing the x-ray beam. It is therefore recommended that the MOSFET dosimeters be oriented with their flat sides facing the beam when they are used at shallow depths or on the surface of either phantoms or patients

  4. Preliminary On-Orbit Neutron Dose Equivalent and Energy Spectrum Results from the ISS-RAD Fast Neutron Detector (FND)

    Science.gov (United States)

    Semones, Edward; Leitgab, Martin

    2016-01-01

    The ISS-RAD instrument was activated on ISS on February 1st, 2016. Integrated in ISS-RAD, the Fast Neutron Detector (FND) performs, for the first time on ISS, routine and precise direct neutron measurements between 0.5 and 8 MeV. Preliminary results for neutron dose equivalent and neutron flux energy distributions from online/on-board algorithms and offline ground analyses will be shown, along with comparisons to simulated data and previously measured neutron spectral data. On-orbit data quality and pre-launch analysis validation results will be discussed as well.

  5. Ultralow dose CT for pulmonary nodule detection with chest X-ray equivalent dose - a prospective intra-individual comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Messerli, Michael [University Zurich, Department of Nuclear Medicine, University Hospital Zurich, Zurich (Switzerland); Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); Kluckert, Thomas; Knitel, Meinhard; Desbiolles, Lotus; Bauer, Ralf W.; Wildermuth, Simon [Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); Waelti, Stephan [Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); University of Montreal, Department of Radiology, CHU Sainte-Justine, Montreal, Quebec (Canada); Rengier, Fabian [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Warschkow, Rene [Cantonal Hospital St. Gallen, Department of Surgery, St. Gallen (Switzerland); Alkadhi, Hatem [University Zurich, Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich (Switzerland); Leschka, Sebastian [Cantonal Hospital St. Gallen, Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland); University Zurich, Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich (Switzerland)

    2017-08-15

    To prospectively evaluate the accuracy of ultralow radiation dose CT of the chest with tin filtration at 100 kV for pulmonary nodule detection. 202 consecutive patients undergoing clinically indicated chest CT (standard dose, 1.8 ± 0.7 mSv) were prospectively included and additionally scanned with an ultralow dose protocol (0.13 ± 0.01 mSv). Standard dose CT was read in consensus by two board-certified radiologists to determine the presence of lung nodules and served as standard of reference (SOR). Two radiologists assessed the presence of lung nodules and their locations on ultralow dose CT. Sensitivity and specificity of the ultralow dose protocol was compared against the SOR, including subgroup analyses of different nodule sizes and types. A mixed effects logistic regression was used to test for independent predictors for sensitivity of pulmonary nodule detection. 425 nodules (mean diameter 3.7 ± 2.9 mm) were found on SOR. Overall sensitivity for nodule detection by ultralow dose CT was 91%. In multivariate analysis, nodule type, size and patients BMI were independent predictors for sensitivity (p < 0.001). Ultralow dose chest CT at 100 kV with spectral shaping enables a high sensitivity for the detection of pulmonary nodules at exposure levels comparable to plain film chest X-ray. (orig.)

  6. Dose limits

    International Nuclear Information System (INIS)

    Fitoussi, L.

    1987-12-01

    The dose limit is defined to be the level of harmfulness which must not be exceeded, so that an activity can be exercised in a regular manner without running a risk unacceptable to man and the society. The paper examines the effects of radiation categorised into stochastic and non-stochastic. Dose limits for workers and the public are discussed

  7. Comparison of dose calculation algorithms in phantoms with lung equivalent heterogeneities under conditions of lateral electronic disequilibrium

    International Nuclear Information System (INIS)

    Carrasco, P.; Jornet, N.; Duch, M.A.; Weber, L.; Ginjaume, M.; Eudaldo, T.; Jurado, D.; Ruiz, A.; Ribas, M.

    2004-01-01

    An extensive set of benchmark measurement of PDDs and beam profiles was performed in a heterogeneous layer phantom, including a lung equivalent heterogeneity, by means of several detectors and compared against the predicted dose values by different calculation algorithms in two treatment planning systems. PDDs were measured with TLDs, plane parallel and cylindrical ionization chambers and beam profiles with films. Additionally, Monte Carlo simulations by meansof the PENELOPE code were performed. Four different field sizes (10x10, 5x5, 2x2, and1x1 cm 2 ) and two lung equivalent materials (CIRS, ρ e w =0.195 and St. Bartholomew Hospital, London, ρ e w =0.244-0.322) were studied. The performance of four correction-based algorithms and one based on convolution-superposition was analyzed. The correction-based algorithms were the Batho, the Modified Batho, and the Equivalent TAR implemented in the Cadplan (Varian) treatment planning system and the TMS Pencil Beam from the Helax-TMS (Nucletron) treatment planning system. The convolution-superposition algorithm was the Collapsed Cone implemented in the Helax-TMS. The only studied calculation methods that correlated successfully with the measured values with a 2% average inside all media were the Collapsed Cone and the Monte Carlo simulation. The biggest difference between the predicted and the delivered dose in the beam axis was found for the EqTAR algorithm inside the CIRS lung equivalent material in a 2x2 cm 2 18 MV x-ray beam. In these conditions, average and maximum difference against the TLD measurements were 32% and 39%, respectively. In the water equivalent part of the phantom every algorithm correctly predicted the dose (within 2%) everywhere except very close to the interfaces where differences up to 24% were found for 2x2 cm 2 18 MV photon beams. Consistent values were found between the reference detector (ionization chamber in water and TLD in lung) and Monte Carlo simulations, yielding minimal differences (0

  8. The consequences of a reduction in the administratively applied maximum annual dose equivalent level for an individual in a group of occupationally exposed workers

    International Nuclear Information System (INIS)

    Harrison, N.T.

    1980-02-01

    An analysis is described for predicting the consequences of a reduction in the administratively applied maximum dose equivalent level to individuals in a group of workers occupationally exposed to ionising radiations, for the situation in which no changes are made to the working environment. This limitation of the maximum individual dose equivalent is accommodated by allowing the number of individuals in the working group to increase. The derivation of the analysis is given, together with worked examples, which highlight the important assumptions that have been made and the conclusions that can be drawn. The results are obtained in the form of the capacity of the particular working environment to accommodate the limitation of the maximum individual dose equivalent, the increase in the number of workers required to carry out the productive work and any consequent increase in the occupational collective dose equivalent. (author)

  9. Potential factors that impact the radon level and the prediction of ambient dose equivalent rates of indoor microenvironments.

    Science.gov (United States)

    Ali, Mohamed Yasreen Mohamed; Hanafiah, Marlia M; Khan, Md Firoz

    2018-01-11

    This study aimed to measure the equilibrium equivalent radon (EEC Rn ) concentration in an old building (Building-1) and a new building (Building-2) with mechanical ventilation and a natural ventilation system, respectively. Both buildings were located at the campus of University Kebangsaan Malaysia. The concentration of indoor radon was measured at 25 sampling stations using a radon detector model DOSEman PRO. The sampling was conducted for 8 h to represent daily working hours. A correlation of the radon concentration was made with the annual inhalation dose of the occupants at the indoor stations. The equilibrium factor and the annual effective dose on the lung cancer risks of each occupant were calculated at each sampling station. The average equilibrium equivalent radon measured in Building-1 and Building-2 was 2.33 ± 0.99 and 3.17 ± 1.74 Bqm -3 , respectively. The equilibrium factor for Building 1 ranged from 0.1053 to 0.2273, and it ranged from 0.1031 to 0.16 for Building 2. The average annual inhalation doses recorded at Building-1 and Building-2 were 0.014 ± 0.005 mSv y -1 and 0.020 ± 0.013 mSv y -1 , respectively. The annual effective dose for Building-1 was 0.034 ± 0.012 mSv y -1 , and it was 0.048 ± 0.031 mSv y -1 for Building-2. The values of equilibrium equivalent radon concentration for both buildings were below the standard recommended by the International Commission on Radiological Protection (ICRP). However, people may have different radon tolerance levels. Therefore, the inhalation of the radon concentration can pose a deleterious health effect for people in an indoor environment. Copyright © 2018. Published by Elsevier B.V.

  10. Transfer factor of sup 131 I from the fallout to human thyroid dose equivalent after the Chernobyl accident

    Energy Technology Data Exchange (ETDEWEB)

    Beno, M.; Hrabina, J. (Research Inst. of Preventive and Clinical Medicine, Bratislava (Czechoslovakia)); Mikulecky, M. (Comenius Univ., Bratislava (Czechoslovakia). 1. Medical Clinic)

    1992-04-01

    A similar pattern of variation with time in observed maxima of daily dose equivalent rates in human thyroids (TD-{mu}Sv.d{sup -1}) and of daily fallout radioactivities (FR-kBq.m{sup -2}) has been found after the Chernobyl accident. An estimate of the time-lag between the maxima in TD lines and the preceding FR peaks was made of about seven days for adult and nine days for juveniles. Applying this time-lag it was possible to estimate transfer factors from the fallout to thyroid dose equivalent: The highest estimated values were 221 {mu}Sv/kBq.m{sup -2} for adult and 641 {mu}Sv/kBq.m{sup -2} for juvenile thyroids. These values differ from those published by UNSCEAR (United Nations 1988), which have been calculated for various regions of Czechoslovakia, from ingestion and inhalation intake estimates. A broad variation of transfer factor values could be expected to result from such transfer calculations using ingestion and inhalation estimates. The findings also support the concept of a need for prolonged iodine prophylaxy after emissions of radioiodine into the environment. (orig.).

  11. Development of a Reference System for the determination of the personal dose equivalent and the constancy of X- Ray beams

    International Nuclear Information System (INIS)

    Vivolo, Vitor

    2006-01-01

    A reference system for the determination of the personal dose equivalent, Hp (10), and a quality control program of X-ray equipment used In radioprotection require the periodic verification of the X-ray beams constancy. In this work, two parallel-plate ionization chambers were developed with inner electrodes of different materials, and inserted into PMMA slab phantoms. One ionization chamber was developed with inner carbon electrodes and the other with inner aluminium electrodes. The two ionization chambers can be used as a Tandem system. The different energy response of the two ionization chambers allowed the development of the Tandem system that is very useful for the checking of the constancy of beam qualities. Standard intermediary energy X-ray beams (from 48 keV to 118 keV), radioprotection level, were established through the development of a dosimetric methodology and the analysis of their physical parameters. The ionization chambers were studied in relation to their operational characteristics, and they were calibrated in X-ray beams (radioprotection, diagnostic radiology, mammography and radiotherapy levels) in accordance to international recommendations. They presented good performance. The determination procedure of personal dose equivalent, Hp (10), was established. (author)

  12. Development of a neutron dosemeter for personnel dosimetry with direct response of dose equivalent in neutron fields of different energy spectra. 1

    International Nuclear Information System (INIS)

    Doerschel, B.

    1978-12-01

    An energy-independent neutron dosemeter is described. The dosemeter is based on a dielectric track detector (mica foil of 6 μm thickness) between uranium and a thorium-232 radiator pulverized and pressed with polyvinyl alcohol enclosed within a cadmium shell. The track density is direct proportional to the dose equivalent between 5 x 10 -4 and 10 Sv. When evaluated every two months, the dosemeter has for 3 mSv an error of +- 50% decreasing at higher dose equivalents

  13. Computer-aided detection (CAD) of solid pulmonary nodules in chest x-ray equivalent ultralow dose chest CT - first in-vivo results at dose levels of 0.13 mSv

    Energy Technology Data Exchange (ETDEWEB)

    Messerli, Michael, E-mail: Michael.Messerli@usz.ch [Division of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen (Switzerland); Kluckert, Thomas; Knitel, Meinhard [Division of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen (Switzerland); Rengier, Fabian [Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg (Germany); Warschkow, René [Department of Surgery, Cantonal Hospital St. Gallen (Switzerland); Alkadhi, Hatem [Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University Zurich (Switzerland); Leschka, Sebastian [Division of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen (Switzerland); Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University Zurich (Switzerland); Wildermuth, Simon; Bauer, Ralf W. [Division of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen (Switzerland)

    2016-12-15

    of CAD (p < 0.001), and nodule size (p < 0.0001) were independent predictors for nodule detection, but not BMI (p = 0.933) and the use of contrast agents (p = 0.176). Conclusions: Computer-aided detection of solid pulmonary nodules using ultralow dose CT with chest X-ray equivalent radiation dose has similar sensitivities to those from standard dose CT. Adding CAD in ultralow dose CT significantly improves the sensitivity of radiologists.

  14. Computer-aided detection (CAD) of solid pulmonary nodules in chest x-ray equivalent ultralow dose chest CT - first in-vivo results at dose levels of 0.13 mSv

    International Nuclear Information System (INIS)

    Messerli, Michael; Kluckert, Thomas; Knitel, Meinhard; Rengier, Fabian; Warschkow, René; Alkadhi, Hatem; Leschka, Sebastian; Wildermuth, Simon; Bauer, Ralf W.

    2016-01-01

    of CAD (p < 0.001), and nodule size (p < 0.0001) were independent predictors for nodule detection, but not BMI (p = 0.933) and the use of contrast agents (p = 0.176). Conclusions: Computer-aided detection of solid pulmonary nodules using ultralow dose CT with chest X-ray equivalent radiation dose has similar sensitivities to those from standard dose CT. Adding CAD in ultralow dose CT significantly improves the sensitivity of radiologists.

  15. Effects of ISS equivalent ionizing radiation dose on Human T-lymphocytes

    Science.gov (United States)

    Meloni, Maria Antonia; Pani, Giuseppe; Benotmane, Rafi; Mastroleo, Felice; Aboul-El-Ardat, Khalil; Janssen, Ann; Leysen, Liselotte; Vanhavere, Filip; Leys, Natalie; Galleri, Grazia; Pippia, Proto; Baatout, Sarah

    One of the objectives of the current international space programs is to investigate the effects of cosmic environment on Humans. It is known that during a long exposure to the space conditions, including ionizing radiations and microgravity, the immune system of the astronauts is impaired. In past years several experiments were performed to identify responsible factors of in vitro mitogenic activation process in human T-lymphocytes under simulated microgravity effect and during dedicated space missions. It come out that the lack of immune response in microgravity occurs at the cellular and molecular level. In order to evaluate effects on pure primary T-lymphocytes from peripheral blood exposed to International Space Station (ISS)-like ionizing radiation, we applied a mixture of Cesium-137, as representative of low energy particles, and Californium-252, as representative of hight energy particles, with rate similar to those monitored inside the ISS during previous space mission (Goossens et all. 2006). This facility is available at SCK•CEN (Belgium) (Mastroleo et al., 2009). Although the dose received by the cells was relatively low, flow cytometry analysis 24 hours after irradiation showed a decrease in cell viability coupled with the increase of the caspase-3 activity. However, Bcl-2 activity did not seem to be affected by the radiation. Furthermore, activation of cells induced an increase of the cell size and alteration of cellular morphology. Cell cycle as well as 8-oxo-G were also modified upon radiation and activation. Gene expression analysis shows a modulation of genes rather as a consequence of exposure than with the activation status. 330 genes have been identified to be significantly modulated in function of the time and have been grouped in four different cluster representing significant expression profiles. Preliminary functional analysis shows mainly genes involved in the immune response and inflammatory diseases as well as oxidative stress and

  16. Atmospheric Cosmic-Ray Variation and Ambient Dose Equivalent Assessments Considering Ground Level Enhancement Thanks to Coupled Anisotropic Solar Cosmic Ray and Extensive Air Shower Modeling.

    Science.gov (United States)

    Hubert, Guillaume; Aubry, Sébastien

    2017-11-01

    This work investigates the impact of Forbush decrease (FD) and ground-level enhancement (GLE) in the atmosphere, based on solar and galactic cosmic-ray models and the extensive air shower simulations. This approach gives the possibility to investigate both the dynamic behavior of neutron monitors (NM) (using response function) and the flight dose. The ambient dose equivalent during quiet solar activity and solar events (i.e., FDs and GLEs) were investigated for realistic flight plans issued from the Eurocontrol Demand Data Repository. The calculated ambient dose equivalents were compared with flight measurements in quiet solar conditions; comparisons are relevant and demonstrate the ability to estimate the dose level. The GLE model was validated for the GLEs 5 and 69 using the cosmic-ray variation recorded by NMs. The GLE model was applied to flight dose calculations. All of these results show that dose values vary drastically with the route path (latitude, longitude and altitude) and with the delay between the flight departure and the solar event occurrence. Doses induced by extreme GLE events were investigated specifically for London to New York flights, and resulting additional doses are a few hundred or 1,000 μSv, impacting significantly the annual effective dose. This highlights the importance of monitoring extreme solar events and using realistic semi-empirical and particle transport methods for reliable calculation of dose levels.

  17. Reliability of equivalent-dose determination and age-models in the OSL dating of historical and modern palaeoflood sediments

    DEFF Research Database (Denmark)

    Medialdea, Alicia; Thomsen, Kristina Jørkov; Murray, Andrew Sean

    2014-01-01

    of minimum over-dispersion (OD) is based on dose recovery tests based on gamma-irradiated samples. We then present a detailed analysis of the effect of an additional uncertainty added to the individual dose estimates on the burial dose estimates from the MAM and the IEU approach. The results of the various...

  18. Controllable dose

    International Nuclear Information System (INIS)

    Alvarez R, J.T.; Anaya M, R.A.

    2004-01-01

    With the purpose of eliminating the controversy about the lineal hypothesis without threshold which found the systems of dose limitation of the recommendations of ICRP 26 and 60, at the end of last decade R. Clarke president of the ICRP proposed the concept of Controllable Dose: as the dose or dose sum that an individual receives from a particular source which can be reasonably controllable by means of any means; said concept proposes a change in the philosophy of the radiological protection of its concern by social approaches to an individual focus. In this work a panorama of the foundations is presented, convenient and inconveniences that this proposal has loosened in the international community of the radiological protection, with the purpose of to familiarize to our Mexican community in radiological protection with these new concepts. (Author)

  19. Neutron equivalent dose rates at the surroundings of the electron linear accelerator operated by the university of Sao Paulo - Physics institute

    International Nuclear Information System (INIS)

    Yanagihara, L.S.

    1984-01-01

    For the determination of the neutron dose rates at the surroundings of an electron linear accelerators it is necessary the knowledge of the neutron spectrum or its mean energy, because the conversion factor of the flux in equivalent dose rates, is strongly dependent on the neutron energy. Taking this fact into consideration, equivalent dose rates were determined in the three representative sites of the IF/USP Linear Electron Accelerator. Also, due to the radiation field be pulsed, a theoretical and experimental study has been realized to evaluate the effect produced by the variation of the field on the detector. (author)

  20. Absorbed dose to water reference dosimetry using various water-equivalent solid phantoms in high-energy photon beams

    International Nuclear Information System (INIS)

    Araki, Fujio; Hanyu, Yuji; Okumura, Masahiko

    2007-01-01

    Most recent megavoltage dosimetry protocols (e.g., the Japan Society of Medical Physics (JSMP) (JSMP-01), the American Association of Physicists in Medicine (AAPM) (TG-51), and the International Atomic Energy Agency (IAEA) (TRS-398)) have limited to the use of liquid water as a phantom material for reference dose measurements. This is because water is well-defined and reproducibly available compared to water-equivalent solid phantoms. This study presents methods to determine absorbed dose to water using ionization chambers calibrated in terms of absorbed dose to water but irradiated in solid phantoms. Achieving solid phantom measurements on an absolute basis has distinct advantages in verification measurements and quality assurance. We provide a depth scaling factor that transfers a depth in the solid phantom to a water equivalent depth and an ionization conversion factor (ionization ratio) that converts a chamber reading in the solid phantom to that in water. The absorbed dose to water under reference conditions can be obtained from the solid phantom measurements by using the two factors. We calculated the depth scaling factor for four solid phantoms (Solid Water RMI457, Tough Water WE211, RW3, and MixDP) for photon energies between 4 and 18 MV. The calculated average scaling factor for each phantom agreed within 1.5% compared with the relative electron density. For various Farmer-type cylindrical chambers, we also calculated and measured the ionization conversion factor for the four solid phantoms. The solid phantom measurements were performed at many hospitals. For RMI457 and WE211, the differences between measured and calculated factors varied between -0.5% and 0.7% with the average ionization conversion factor 0.3% lower than the calculation, whereas RW3 agreed within 0.5% after one phantom examination. Similarly, the differences for MixDP ranged from -0.2% to -1.5% with the average 1.0% lower than the calculation. The composition of commercial plastic

  1. Dose from radiological examinations

    International Nuclear Information System (INIS)

    Imamura, Keiko; Uji, Teruyuki; Sakuyama, Keiko; Fujikawa, Mitsuhiro; Fujii, Masamichi

    1976-01-01

    Relatively high gonad doses, several hundred to one thousand mR, have been observed in case of pelvis, hip-joint, coccyx, lower abdomen and lumber examination. Dose to the ovary is especially high in barium enema and I.V.P. examinations. About 12 per cent of the 4-ray examination are high-dose. The gonad dose is relatively high in examination of abdomen and lower extremities, in infants. The dose to the eyes is especially high, 1.0 to 2.5R per exposure, in temporal bone and nasal sinuses tomography. X-ray doses have been compared with dose limits recommended by ICRP and with the gonad dose from natural radiations. The gonad dose in lumbar examination, barium enema, I.V.P. etc. is as high as the maximum permissible dose per year recommended by ICRP. Several devices have been made for dose reduction in the daily examinations: (1) separating the radiation field from the gonad by one centimeter decreases the gonad dose about one-half. (2) using sensitive screens and films. In pelvimetry and in infant hip-joint examination, the most sensitive screen and film are used. In the I.V.P. examination of adult, use of MS screen in place of FS screen decreases the dose to one-third, in combination with careful setting of radiation field, (3) use of grid increases the dose about 50 percent and the lead rubber protection (0.1mm lead equivalent) decreases the gonad dose to one-thirtieth in the spinal column examination of infant, (4) A lead protector, 1mm thickness and 2.5cm in diameter, on the eyes decreases the dose to about one-eighth in the face and nead examinations. These simple and effective methods for dose reduction. Should be carried out in as many examinations as possible in addition to observing dose limits recommended by ICRP. (Evans, J.)

  2. Determination of attenuation factors for mortar of barite in terms of environmental dose equivalent and effective dose; Determinacao de fatores de atenuacao para argamassa de barita em termos do equivalente de dose ambiental e dose efetiva

    Energy Technology Data Exchange (ETDEWEB)

    Almeida Junior, Airton T.; Campos, L.L.R., E-mail: airtontavares@uol.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Araujo, F.G.S. [Universidade Federal de Ouro Preto (UFOP), Ouro Preto, MG (Brazil); Santos, M.A.P. [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Nogueira, M.S., E-mail: mnogueira@cdtn.br [Centro de Desenvolvimeto da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2014-07-01

    This work addresses the characterization of barite mortars used as Xray shielding materials through the following quantities: mass attenuation coefficient, air kerma, effective dose and ambient dose - H⁎(10). The experiment was carried out with the use of the following reference qualities: RQR4, RQR6, RQR9 e RQR10, specified in accordance with norm IEC 61267: Medical diagnostic Xray equipment - radiation conditions for use in the determination of characteristics. In this study values was determined experimentally for the attenuation of the Cream barite (density 2.99g/cm{sup 3}, collected in the state of Sao Paulo), Purple barite (density 2.95g/cm{sup 3}, collected in the state of Bahia) and White barite (density 3.10g/cm{sup 3}, collected in the state of Paraiba). These materials, in the form of mortar, were disposed in the form of squares namely poof bodies, whose dimensions were 10 x 10 cm and thickness ranging from 3 to 15 mm approximately. In the experimental procedure, these proof bodies were irradiated with a Pantak, model HF320 industrial X-ray apparatus. The potentials applied to the respective X-ray tube were: 60kV, 80kV, 120kV and 150kV at a constant current of 1mA. The attenuation responses in function of thickness, for each of the materials analyzed, were used to draw the attenuation and transmission curves. The efficiency of the barite studied concerning the capacity to attenuate X-ray radiation for X-ray beams ranging from 60 to 150 kV indicated.

  3. Thyroid equivalent dose in staffs that use neck lead protector in pediatric barium meal; Dose equivalente na tireoide dos profissionais que utilizam o protetor plumbifero nos exames de seed pediatrico

    Energy Technology Data Exchange (ETDEWEB)

    Filipov, Danielle; Sauzen, Jessica; Paschuk, Sergei A., E-mail: dfilipov@utfpr.edu.br [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Schelin, Hugo R.; Denyak, Valeriy [Instituto de Pesquisa Pele Pequeno Principe (IPPP), Curitiba, PR (Brazil); Legnani, Adriano [Hospital Pequeno Principe, Curitiba, PR (Brazil)

    2015-08-15

    The aim of this study is to estimate the thyroid equivalent dose in staffs that perform pediatric barium meal procedures and use neck lead protector. Thermoluminescent Dosimeters (TLDs) were positioned on the lead protectors, used by two professionals. After that, a solid state detector was exposed (with and without the protector above it). Therefore, it was possible to obtain both lead protectors attenuation factors. At the end, average and annual doses received by the TLDs and the thyroid (applying the attenuation factor over the dosimeters doses) were obtained. It was found that the average and annual equivalent doses in the thyroid gland are, respectively, higher than in comparative studies and within the established limits. With these data, it is concluded that the application of radiation protection optimization techniques is required. (author)

  4. Evaluation of patient skin dose equivalent due to diagnostic procedures with X-rays in Lagos State Nigeria

    International Nuclear Information System (INIS)

    Aweda, M.A.

    2001-01-01

    This paper reports the study of Patient Skin Dose Equivalents in Lagos State, Nigeria, as one of the strategies of patient protection and x-ray procedure quality assessment. 13 most frequent x-ray diagnostic procedures were studied, these were: chest, skull, cervical spine, lumbosacral spine, sinusis, pelvis, plain abdomen, shoulder, foot, hysterosalpingography, intravenous urography, barium meal and barium enema. 1977 procedures were monitored for a period of 12 months in both private and public hospitals carefully selected from all over the state. The results obtained compared favorably well with those from similar studies reported in the literature. The slight differences observed have been ascribed to variations in the patient anatomy, exposure conditions and choice of radiographic parameters. (author)

  5. The study of equivalent dose of uranium in long bean (V. U. Sesquipedalis) and the effect on human

    Energy Technology Data Exchange (ETDEWEB)

    Rashid, Nur Shahidah Abdul; Yoshandi, Tengku Mohammad; Majid, Sukiman Sarmania Amran Ab.; Mohamed, Faizal; Siong, Khoo Kok, E-mail: khoo@ukm.edu.my [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia)

    2016-01-22

    In the case of accidental release of Uranium-238 ({sup 238}U) radionuclides in a nuclear facility or in the environment, internal contamination by either acute or chronic exposure has the potential to induce both radiological and chemical toxic effects. A study was conducted to estimate the {sup 238}U radionuclide concentration in the long beans using Induced Coupled Mass Plasma-Spectrometry (ICP-MS). {sup 238}U radionuclide is a naturally occurring radioactive material that can be found in soil and can be transferred to the long bean (Vigna unguiculata subsp. Sesquapedalis) directly or indirectly via water or air. Kidney and liver are the major sites of deposition of {sup 238}U radionuclide. The obtained dose exposed in the liver and kidney is used to assess the safety level for public intake of {sup 238}U radionuclide from the consumption of long beans. The concentration of {sup 238}U radionuclide measured in long bean samples was 0.0226 ± 0.0009 mg/kg. Total activity of {sup 238}U radionuclide was 0.0044 ± 0.0002 Bq/day with the daily intake of 0.3545 ± 0.0143 µg/day and the annual committed effective dose due to ingestion of {sup 238}U radionuclide in long beans was 0.2230 ± 0.0087 µSv/year. The committed equivalent dose of {sup 238}U radionuclide from the assessment in the liver and kidney are 0.4198 ± 0.0165 nSv and 10.9335 ± 0.4288 nSv. The risk of cancer of {sup 238}U radionuclide was determined to be (86.0466 ± 3.3748) × 10-9. Thus, the results concluded that {sup 238}U radionuclide in local long beans was in the permitted level and safe to consume without posing any significant radiological threat to population.

  6. The study of equivalent dose of uranium in long bean (V. U. Sesquipedalis) and the effect on human

    International Nuclear Information System (INIS)

    Rashid, Nur Shahidah Abdul; Yoshandi, Tengku Mohammad; Majid, Sukiman Sarmania Amran Ab.; Mohamed, Faizal; Siong, Khoo Kok

    2016-01-01

    In the case of accidental release of Uranium-238 ( 238 U) radionuclides in a nuclear facility or in the environment, internal contamination by either acute or chronic exposure has the potential to induce both radiological and chemical toxic effects. A study was conducted to estimate the 238 U radionuclide concentration in the long beans using Induced Coupled Mass Plasma-Spectrometry (ICP-MS). 238 U radionuclide is a naturally occurring radioactive material that can be found in soil and can be transferred to the long bean (Vigna unguiculata subsp. Sesquapedalis) directly or indirectly via water or air. Kidney and liver are the major sites of deposition of 238 U radionuclide. The obtained dose exposed in the liver and kidney is used to assess the safety level for public intake of 238 U radionuclide from the consumption of long beans. The concentration of 238 U radionuclide measured in long bean samples was 0.0226 ± 0.0009 mg/kg. Total activity of 238 U radionuclide was 0.0044 ± 0.0002 Bq/day with the daily intake of 0.3545 ± 0.0143 µg/day and the annual committed effective dose due to ingestion of 238 U radionuclide in long beans was 0.2230 ± 0.0087 µSv/year. The committed equivalent dose of 238 U radionuclide from the assessment in the liver and kidney are 0.4198 ± 0.0165 nSv and 10.9335 ± 0.4288 nSv. The risk of cancer of 238 U radionuclide was determined to be (86.0466 ± 3.3748) × 10-9. Thus, the results concluded that 238 U radionuclide in local long beans was in the permitted level and safe to consume without posing any significant radiological threat to population

  7. High dose amoxicillin-based first line regimen is equivalent to sequential therapy in the eradication of H. pylori infection.

    Science.gov (United States)

    Franceschi, F; Ojetti, V; Gabrielli, M; Petruzziello, C; Tortora, A; Gasbarrini, G; Lopetuso, L R; Scaldaferri, F; Gasbarrini, A

    2016-01-01

    Helicobater (H.) pylori eradication rates with standard first-line triple therapy have declined to unacceptable levels. To date, amoxicillin-resistant H. pylori strains have rarely been detected. Whether increasing the dosage of amoxicillin in a standard 7 days eradicating regimen may enhance its efficacy is not known. The aim of this paper is to compare the efficacy of a 7 days high-dose amoxicillin based first-line regimen with sequential therapy. We have retrospectively analyzed data from 300 sex and age matched patients, who underwent 3 different therapeutic schemes: (1) standard LCA, lansoprazole 30 mg bid, clarithromycin 500 mg bid and amoxicillin 1000 mg bid for 7 days; (2) high dose LCA (HD-LCA), lansoprazole 30 mg bid, clarithromycin 500 mg bid and amoxicillin 1000 mg tid for 7 days; (3) sequential LACT, lansoprazole 30 mg bid plus amoxicillin 1000 mg bid for 5 days, followed by lansoprazole 30 mg bid, clarithromycin 500 mg bid and tinidazole 500 mg bid for 5 days. Eradication was confirmed by 13C-urea breath test. Compliance and occurrence of adverse effects were also assessed. Eradication rates were: 55% for LCA, 75% for HD-LCA and 73% for LACT. Eradication rates were higher in HD-LCA group compared to LCA (pamoxicillin based eradicating treatment is superior to standard triple therapy and equivalent to sequential therapy; compared to the latter, the shorter duration may represent an advantage.

  8. Radial dose, LET, and W-bar for 16O ions in N2 and tissue-equivalent gases

    International Nuclear Information System (INIS)

    Varma, M.N.; Baum, J.W.; Kuehner, A.V.

    1977-01-01

    Average energy to produce an ion pair (anti W), distance restricted, and total linear energy transfer and dose as a function of radial distance D(r) from the ion's path were measured for 41.1-MeV 16 O ions in nitrogen and Rossi-type tissue-equivalent gas. Results for anti W were 38.9 +- 0.54 eV/ion pair for nitrogen and 33.4 +- 0.47 eV/ion pair for tissue-equivalent gas. Results for total linear energy transfer (LET/sub infinity/) were 6507 MeV . cm 2 g -1 for tissue-equivalent gas and 6210 MeV . cm 2 g -1 for nitrogen. Results for D(r) were used to calculate similar values to be expected in tissue-like material having a density of 1 g/cm 3 . The range of radial distances covered was from 0.2 to 300 nm in tissue. Results are compared with calculations based on Paretzke's continuous slowing down model. Measured D(r) values in nitrogen were randomly distributed about the calculated values between radial distances of 0.56 and 286 nm. The mean deviation between the experimental and the calculated value was 1.3% (the experimental value being higher). For tissue-equivalent gas, previously measured D(r) values were also randomly distributed about the calculated values, with a mean deviation of 4% (the experimental value being lower) between radial distances of 1.5 and 140 nm

  9. Effective Equivalent Doses of External Irradiation of Population by Man-made Radionuclides from the Soil in the Sarajevo Region Over the Period of 1986-1989

    International Nuclear Information System (INIS)

    Saracevic, L.; Samek, D.; Hasanbasic, D.; Gradascevic, N.

    1998-01-01

    Assessment of exposition of human body to radioactive materials is seen as radiation-hygienic measure of utmost importance, since the doses absorbed due to radionuclides present in soil, air, food and water are significant integral parts of the total dose that the human being receives in all kinds and conditions of exposition. External irradiation by radionuclides deposed in soil is a major contributor to the whole dose of irradiation of population. Assuming that fission radionuclides Cs-134 and Cs-137 had a specially significant contribution to the total dose of irradiation of the population over the investigation period (1986-1989), we established their levels of activity in the soil in different localities of the Sarajevo region, and then calculated the effective equivalent dose for the population for each year of investigation. The mean values for the yearly effective equivalent doses of external irradiation of the population by fission radionuclides Cs-134 and Cs-137 from the soil in the Sarajevo region were 0.77 mSv/year in 1989. Contribution by Cs-134 to the total effective equivalent dose was 63.64 % in 1986 year, to be reeducated in 1987 to 45.67 %, in 1988 to 35.89 % and in the year 1989 to 33.33 %. The effective equivalent dose was different to a great extent by the investigated localities (town sections) during the started period. It can be inferred from the above that the average population of the Sarajevo region did not receive a larger dose of radiation than the one established by the International Commission for Radiological Protection as the limit for subsequent exposition to radiation. (author)

  10. Estimation of neutron dose equivalent at the mezzanine of the Advanced Light Source and the laboratory boundary using the ORNL program MORSE.

    Science.gov (United States)

    Sun, R K

    1990-12-01

    To investigate the radiation effect of neutrons near the Advanced Light Source (ALS) at Lawrence Berkeley Laboratory (LBL) with respect to the neutron dose equivalents in nearby occupied areas and at the site boundary, the neutron transport code MORSE, from Oak Ridge National Laboratory (ORNL), was used. These dose equivalents result from both skyshine neutrons transported by air scattering and direct neutrons penetrating the shielding. The ALS neutron sources are a 50-MeV linear accelerator and its transfer line, a 1.5-GeV booster, a beam extraction line, and a 1.9-GeV storage ring. The most conservative total occupational-dose-equivalent rate in the center of the ALS mezzanine, 39 m from the ALS center, was found to be 1.14 X 10(-3) Sv y-1 per 2000-h "occupational" year, and the total environmental-dose-equivalent rate at the ALS boundary, 125 m from the ALS center, was found to be 3.02 X 10(-4) Sv y-1 per 8760-h calendar year. More realistic dose-equivalent rates, using the nominal (expected) storage-ring current, were calculated to be 1.0 X 10(-4) Sv y-1 and 2.65 X 10(-5) Sv y-1 occupational year and calendar year, respectively, which are much lower than the DOE reporting levels.

  11. Dose and dose rate monitor

    International Nuclear Information System (INIS)

    Novakova, O.; Ryba, J.; Slezak, V.; Svobodova, B.; Viererbl, L.

    1984-10-01

    The methods are discussea of measuring dose rate or dose using a scintillation counte. A plastic scintillator based on polystyrene with PBD and POPOP activators and coated with ZnS(Ag) was chosen for the projected monitor. The scintillators were cylindrical and spherical in shape and of different sizes; black polypropylene tubes were chosen as the best case for the probs. For the counter with different plastic scintillators, the statistical error 2σ for natural background was determined. For determining the suitable thickness of the ZnS(Ag) layer the energy dependence of the counter was measured. Radioisotopes 137 Cs, 241 Am and 109 Cd were chosen as radiation sources. The best suited ZnS(Ag) thickness was found to be 0.5 μm. Experiments were carried out to determine the directional dependence of the detector response and the signal to noise ratio. The temperature dependence of the detector response and its compensation were studied, as were the time stability and fatigue manifestations of the photomultiplier. The design of a laboratory prototype of a dose rate and dose monitor is described. Block diagrams are given of the various functional parts of the instrument. The designed instrument is easiiy portable, battery powered, measures dose rates from natural background in the range of five orders, i.e., 10 -2 to 10 3 nGy/s, and allows to determine a dose of up to 10 mGy. Accouracy of measurement in the energy range of 50 keV to 1 MeV is better than +-20%. (E.S.)

  12. Occupational dose equivalent limits

    International Nuclear Information System (INIS)

    Goldfinch, E.P.

    1980-01-01

    This paper considers methods of limiting individual radiation risks by recognizing the variation of risk with age at exposure, taking into account both somatic and genetic risks and proposes a simple formula for controlling individual cumulative exposure and hence risk. (Author)

  13. Determination of the dose equivalent Hp(0.07) in hands of occupationally exposed personnel in the practice of proton emission tomography (PET/CT)

    International Nuclear Information System (INIS)

    Lea, D.; Ruiz, N.; Esteves, L.

    2006-01-01

    In Venezuela recently it was implanted the Positron Emission Tomography technique (PET) with the perspective of implanting it at national level. Even when in our country practices it of nuclear medicine it exists from early of 70, there is not experience in the determination of the occupational doses by exposure to the external radiation in hands. By this reason, a concern exists in the workers of the centers of nuclear medicine where it is practiced the Positron Emission Tomography technique. In absence of the TLD dosimetry to measure dose in hands in our country, measurements of the dose equivalent of the workers of the PET national reference center were made, using a detector of hands type diode. It was determined the dose in hands in terms of dose equivalent Hp(0.07) in two work positions, that is: the corresponding to the transfer of the receiving vial of ( 18 F) FDG to the shield, quality control and uni doses division. The second work position corresponds the person in charge of administering, via intravenous, the ( 18 F) FDG. In this work it realizes the dose equivalent in hands Hp(0.07) measures in each one of the work positions before described by daily production. The informed doses correspond to a total average produced activity of 20.4 GBq (550 mCi). The results of the measurements in terms of dose equivalent in hands Hp(0.07) correspond to 2.1 ± 20% mSv in the work position of division and 0.4 ± 10% mSv in the position of injection of the radioactive material. At short term this foreseen until 4 productions per week, what means an annual dose equivalent Hp(0.07) in hands of 400 mSv approximately, without taking into account abnormal situations as its are spills of the ( 18 F) FDG in the work place. This work is the starting point so that the regulatory authority settles down, in Venezuela, dose restrictions in the PET practices and implant, in the centers of nuclear medicine, an optimization politics of this practice in conformity with the ALARA

  14. A volume-equivalent spherical necrosis-tumor-normal liver model for estimating absorbed dose in yttrium-90 microsphere therapy.

    Science.gov (United States)

    Wu, Chin-Hui; Liao, Yi-Jen; Lin, Tzung-Yi; Chen, Yu-Cheng; Sun, Shung-Shung; Liu, Yen-Wan Hsueh; Hsu, Shih-Ming

    2016-11-01

    Primary hepatocellular carcinoma and metastatic liver tumors are highly malignant tumors in Asia. The incidence of fatal liver cancer is also increasing in the United States. The aim of this study was to establish a spherical tumor model and determine its accuracy in predicting the absorbed dose in yttrium-90 (Y-90) microsphere therapy for liver cancer. Liver morphology can be approximated by a spherical model comprising three concentric regions representing necrotic, tumor, and normal liver tissues. The volumes of these three regions represent those in the actual liver. A spherical tumor model was proposed to calculate the absorbed fractions in the spherical tumor, necrotic, and normal tissue regions. The THORplan treatment planning system and Monte Carlo N-particle extended codes were used for this spherical tumor model. Using the volume-equivalent method, a spherical tumor model was created to calculate the total absorbed fraction [under different tumor-to-healthy-liver ratios (TLRs)]. The patient-specific model (THORplan) results were used to verify the spherical tumor model results. The results for both the Y-90 spectrum and the Y-90 mean energy indicated that the absorbed fraction was a function of the tumor radius and mass. The absorbed fraction increased with tumor radius. The total absorbed fractions calculated using the spherical tumor model for necrotic, liver tumor, and normal liver tissues were in good agreement with the THORplan results, with differences of less than 3% for TLRs of 2-5. The results for the effect of TLR indicate that for the same tumor configuration, the total absorbed fraction decreased with increasing TLR; for the same shell tumor thickness and TLR, the total absorbed fraction was approximately constant; and for tumors with the same radius, the total fraction absorbed by the tumor increased with the shell thickness. The results from spherical tumor models with different tumor-to-healthy-liver ratios were highly consistent with the

  15. Development and use of a fifteen year-old equivalent mathematical phantom for internal dose calculations. [Radiation dose distributions from /sup 99m/Tc-labeled compounds

    Energy Technology Data Exchange (ETDEWEB)

    Jones, R.M.; Poston, J.W.; Hwang, J.L.; Jones, T.D.; Warner, G.G.

    1976-06-01

    The existence of a phantom based on anatomical data for the average fifteen-year-old provides for a proficient means of obtaining estimates of absorbed dose for children of that age. Dimensions representative of an average fifteen-year-old human, obtained from various biological and medical research, were transformed into a mathematical construct of idealized shapes of the exterior, skeletal system, and internal organs of a human. The idealization for an average adult presently in use by the International Commission on Radiological Protection was used as a basis for design. The mathematical equations describing the phantom were developed to be readily adaptable to present-day methods of dose estimation. Typical exposure situations in nuclear medicine have previously been modeled for existing phantoms. With no further development of the exposure model necessary, adaptation to the fifteen-year-old phantom demonstrated the utility of the design. Estimates of absorbed dose were obtained for the administration of two radiopharmaceuticals, /sup 99m/Tc-sulfur colloid and /sup 99m/Tc-DMSA. (auth)

  16. Comparison of Diagnostic Accuracy of Radiation Dose-Equivalent Radiography, Multidetector Computed Tomography and Cone Beam Computed Tomography for Fractures of Adult Cadaveric Wrists.

    Science.gov (United States)

    Neubauer, Jakob; Benndorf, Matthias; Reidelbach, Carolin; Krauß, Tobias; Lampert, Florian; Zajonc, Horst; Kotter, Elmar; Langer, Mathias; Fiebich, Martin; Goerke, Sebastian M

    2016-01-01

    To compare the diagnostic accuracy of radiography, to radiography equivalent dose multidetector computed tomography (RED-MDCT) and to radiography equivalent dose cone beam computed tomography (RED-CBCT) for wrist fractures. As study subjects we obtained 10 cadaveric human hands from body donors. Distal radius, distal ulna and carpal bones (n = 100) were artificially fractured in random order in a controlled experimental setting. We performed radiation dose equivalent radiography (settings as in standard clinical care), RED-MDCT in a 320 row MDCT with single shot mode and RED-CBCT in a device dedicated to musculoskeletal imaging. Three raters independently evaluated the resulting images for fractures and the level of confidence for each finding. Gold standard was evaluated by consensus reading of a high-dose MDCT. Pooled sensitivity was higher in RED-MDCT with 0.89 and RED-MDCT with 0.81 compared to radiography with 0.54 (P = radiography (P radiography. Readers are more confident in their reporting with the cross sectional modalities. Dose equivalent cross sectional computed tomography of the wrist could replace plain radiography for fracture diagnosis in the long run.

  17. Project ''PHANTOM'' - measurement of the absorbed dose, the ''averaged LET'' and the thermal neutron fluence in a tissue equivalent Phantom onboard space station MIR

    International Nuclear Information System (INIS)

    Berger, T.; Hajek, M.; Vana, N.; Schoener, W.; Akatov, Y.; Shurshakov, V.; Arkhangelsky, V.

    2001-01-01

    A water filled phantom with a diameter of 35 cm was developed at the Institute for Biomedical Problems. This tissue equivalent phantom is equipped with 4 channels to deposit dosemeters in different depths. In the framework of the project 'PHANTOM' (phase 1-3) thermoluminescent dosemeters of the commercially available Types TLD - 600 and TLD - 700 were exposed from May 1997 to February 1999 for an overall of 572 days in the different channels (perpendicular and normal to the hull of the spacecraft) of the phantom. The phantom was positioned in the commander cabin, the board engineer cabin and in the module KWANT 2. Besides the measurement of the depth dose distribution, the 'averaged LET' was determined using the HTR - method. The HTR - method utilizes the different LET - efficiencies of the main - and the high temperature glow peaks of LiF dosemeters for the evaluation of the 'averaged LET' in mixed radiation fields. Therefore it is possible to calculate the depth distribution of the biologically relevant dose equivalent. The results show, that despite of the depth decrease of the absorbed dose, the depth dose equivalent is almost constant. This can be explained by the production of secondary particles inside the phantom. The flux of the thermal neutrons was determined using the pair method. Calibration was performed at the research reactor of the Austrian Universities. First results show, that the contribution of thermal neutrons are roughly 10% of the total neutron dose equivalent. (orig.) [de

  18. A novel method for patient exit and entrance dose prediction based on water equivalent path length measured with an amorphous silicon electronic portal imaging device

    International Nuclear Information System (INIS)

    Kavuma, Awusi; Glegg, Martin; Metwaly, Mohamed; Currie, Garry; Elliott, Alex

    2010-01-01

    In vivo dosimetry is one of the quality assurance tools used in radiotherapy to monitor the dose delivered to the patient. Electronic portal imaging device (EPID) images for a set of solid water phantoms of varying thicknesses were acquired and the data fitted onto a quadratic equation, which relates the reduction in photon beam intensity to the attenuation coefficient and material thickness at a reference condition. The quadratic model is used to convert the measured grey scale value into water equivalent path length (EPL) at each pixel for any material imaged by the detector. For any other non-reference conditions, scatter, field size and MU variation effects on the image were corrected by relative measurements using an ionization chamber and an EPID. The 2D EPL is linked to the percentage exit dose table, for different thicknesses and field sizes, thereby converting the plane pixel values at each point into a 2D dose map. The off-axis ratio is corrected using envelope and boundary profiles generated from the treatment planning system (TPS). The method requires field size, monitor unit and source-to-surface distance (SSD) as clinical input parameters to predict the exit dose, which is then used to determine the entrance dose. The measured pixel dose maps were compared with calculated doses from TPS for both entrance and exit depth of phantom. The gamma index at 3% dose difference (DD) and 3 mm distance to agreement (DTA) resulted in an average of 97% passing for the square fields of 5, 10, 15 and 20 cm. The exit dose EPID dose distributions predicted by the algorithm were in better agreement with TPS-calculated doses than phantom entrance dose distributions.

  19. Method for measuring dose-equivalent in a neutron flux with an unknown energy spectra and means for carrying out that method

    Science.gov (United States)

    Distenfeld, Carl H.

    1978-01-01

    A method for measuring the dose-equivalent for exposure to an unknown and/or time varing neutron flux which comprises simultaneously exposing a plurality of neutron detecting elements of different types to a neutron flux and combining the measured responses of the various detecting elements by means of a function, whose value is an approximate measure of the dose-equivalent, which is substantially independent of the energy spectra of the flux. Also, a personnel neutron dosimeter, which is useful in carrying out the above method, comprising a plurality of various neutron detecting elements in a single housing suitable for personnel to wear while working in a radiation area.

  20. A MULTI-ELEMENT THICK GAS ELECTRON MULTIPLIER-BASED MICRODOSEMETER FOR MEASUREMENT OF NEUTRONS DOSE-EQUIVALENT: A MONTE CARLO STUDY.

    Science.gov (United States)

    Moslehi, A; Raisali, G

    2017-11-01

    To determine the dose-equivalent of neutrons in an extended energy range, in the present work a multi-element thick gas electron multiplier-based microdosemeter made of PMMA (Perspex) walls of 10 mm in thickness is designed. Each cavity is filled with the propane-based tissue-equivalent (TE) gas simulating 1 µm of tissue. Also, a few weight fractions of 3He are assumed to be added to the TE gas. The dose-equivalents are determined for 11 neutron energies between thermal and 14 MeV using the lineal energy distributions calculated by Geant4 simulation toolkit and also the lineal energy-based quality factors. The results show that by adding 0.04% of 3He to the TE gas in each cavity, an energy-independent dose-equivalent response within 30% uncertainty around a median value of 0.91 in the above energy range is achieved. It is concluded that after its construction, the studied microdosemeter can be used to measure the dose-equivalent of neutrons, favorably. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Electron fluence to dose equivalent conversion factors calculated with EGS3 for electrons and positrons with energies from 100 keV to 20 GeV

    International Nuclear Information System (INIS)

    Rogers, D.W.O.

    1983-01-01

    At NRC the general purpose Monte-Carlo electron-photon transport code EGS3 is being applied to a variety of radiation dosimetry problems. To test its accuracy at low energies a detailed set of depth-dose curves for electrons and photons has been generated and compared to previous calculations. It was found that by changing the default step-size algorithm in EGS3, significant changes were obtained for incident electron beam cases. It was found that restricting the step-size to a 4% energy loss was appropriate below incident electron beam energies of 10 MeV. With this change, the calculated depth-dose curves were found to be in reasonable agreement with other calculations right down to incident electron energies of 100 keV although small (less than or equal to 10%) but persistent discrepancies with the NBS code ETRAN were obtained. EGS3 predicts higher initial dose and shorter range than ETRAN. These discrepancies are typical of a wide range of energies as is the better agreement with the results of Nahum. Data is presented for the electron fluence to maximal dose equivalent in a 30 cm thick slab of ICRU 4-element tissue irradiated by broad parallel beams of electrons incident normal to the surface. On their own, these values only give an indication of the dose equivalent expected from a spectrum of electrons since one needs to fold the spectrum maximal dose equivalent value. Calculations have also been done for incident positron beams. Despite the large statistical uncertainties, maximal dose equivalent although their values are 5 to 10% lower in a band around 10 MeV

  2. Photo neutron dose equivalent rate in 15 MV X-ray beam from a Siemens Primus Linac.

    Science.gov (United States)

    Ghasemi, A; Pourfallah, T Allahverdi; Akbari, M R; Babapour, H; Shahidi, M

    2015-01-01

    Fast and thermal neutron fluence rates from a 15 MV X-ray beams of a Siemens Primus Linac were measured using bare and moderated BF3 proportional counter inside the treatment room at different locations. Fluence rate values were converted to dose equivalent rate (DER) utilizing conversion factors of American Association of Physicist in Medicine's (AAPM) report number 19. For thermal neutrons, maximum and minimum DERs were 3.46 × 10(-6) (3 m from isocenter in +Y direction, 0 × 0 field size) and 8.36 × 10(-8) Sv/min (in maze, 40 × 40 field size), respectively. For fast neutrons, maximum DERs using 9" and 3" moderators were 1.6 × 10(-5) and 1.74 × 10(-5) Sv/min (2 m from isocenter in +Y direction, 0 × 0 field size), respectively. By changing the field size, the variation in thermal neutron DER was more than the fast neutron DER and the changes in fast neutron DER were not significant in the bunker except inside the radiation field. This study showed that at all points and distances, by decreasing field size of the beam, thermal and fast neutron DER increases and the number of thermal neutrons is more than fast neutrons.

  3. A conversion method of air-kerma from the primary, scatter and leakage radiations to ambient dose equivalent for calculating the mamography x-ray shielding barrier

    International Nuclear Information System (INIS)

    Kharrati, H.

    2005-01-01

    The primary, scatter, and leakage doses(in Gy), which constitute the data base for calculating shielding requirements for x-ray facilities, are often converted to the equivalent dose (in sievert) by using a constant of conversion of 1.145Sv/Gy. This constant is used for diagnostic radiology as well as for mammography spectra, and is derived by considering an exposure of 1 R corresponds to an air kerma of 8.73 m Gy, which renders by tradition an equivalent dose of 10 mSv. However, this conversion does not take into account the energy dependence of the conversion coefficients relating air kerma to the equivalent dose as described in ICRU report. Moreover, current radiation protection standards propose the use of the quantity ambient dose equivalent in order to qualify the efficiently of given radiation shielding. Therefore, in this study, a new approach has been introduced for derivation ambient dose equivalent from air kerma to calculate shielding requirements in mammography facilities. This new approach has been used to compute the conversion coefficients relating air kerma to ambient dose equivalent for mammography reference beam series of the Netherlands Metrology Institute Van Swinden Laboratorium (NMi), National Institute of Standards and Technology (NIST), and International Atomic Energy Agency (AIEA) laboratories. The calculation has been performed by the means of two methods which show a maximum deviation less than 10%2 for the primary, scatter, and leakage radiations. The results show that the conversion coefficients vary from 0.242 Sv/ Gy to 0.692 Sv/Gy with an average value of 0.436 Sv/Gy for the primary and the scatter radiations, and form 0.156 Sv/Gy to 1.329 Sv/Gy with an average value of 0.98 Sv/Gy for the leakage radiation. Simpkin et al. using an empirical approach propose a conversion value of 0.50 Sv/Gy for the mammography x-ray spectra. This value approximately coincides with the average conversion value of 0.436 Sv/Gy obtained in this work for

  4. Evaluation of personal dose equivalent 'HP(d)' in a external individual monitoring system for X and gamma radiation

    International Nuclear Information System (INIS)

    Santoro, C.; Antonio Filho, J.; Santos, M.A.P.

    2007-01-01

    The good of individual monitoring for external radiation is the assessment of occupational exposure from X and γ radiations in order to assure that the radiological conditions of the workplace are acceptable, safe and satisfactory. The evaluation of radiations doses for workers must not exceed dose limits specified for workers, according to national regulatory agencies. Nowadays, there are two external monitoring systems in use, both based on ICRU definitions. In the conventional system, the workers doses are evaluated in terms of Hx. The personal dosimeter is worn over chest surface and it is calibrated in function of air kerma. In the new system, the workers doses are evaluated in terms of HP(d) and the personal dosimeter is calibrated in function of phantom doses. The aim of this paper is to adapt an external dosimetry laboratory (based on photographic dosimetry) to evaluate the personal dosimeters in terms of HP(d). In this way, a simple methodology, based on linear programming, was utilized. In this adaptation, calibration curves were obtained for radiation qualities (W and N series) described by International Organization for Standardization (ISO 4037-1, 1995). These calibration curves offer a better accuracy on dose determinations and energy below 140 keV, improving the quality of service rendered the society. (author)

  5. Angular and energy dependence of radiation protection monitors to the quantity ambient dose equivalent for gamma radiation;Dependencia angular e energetica de monitores de radioprotecao para medidas de equivalente de dose ambiental para radiacao gama

    Energy Technology Data Exchange (ETDEWEB)

    Nonato, Fernanda B.C.; Carvalho, Valdir S.; Diniz, Raphael E.; Caldas, Linda V.E. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    In Brazil, most of the equipment used for monitoring area is just used in the quantities exposure and absorbed dose, with the need of adjustment to the ambient dose equivalent, H{sup *}(10). In this work, 19 Geiger-Mueller detectors and 7 ionization chambers were calibrated in the Calibration Laboratory of the Instituto de Pesquisas Energeticas Nucleares, IPEN. The energy dependence of these radiation detectors was studied for gamma radiation ({sup 137}Cs e {sup 60}Co) and the angular dependence, for {sup 137}Cs radiation. (author)

  6. Study of the radiation scattered and produced by concrete shielding of radiotherapy rooms and its effects on equivalent doses in patients' organs

    International Nuclear Information System (INIS)

    Braga, K.L.; Rebello, W.F.; Andrade, E.R.; Gavazza, S.; Medeiros, M.P.C.; Mendes, R.M.S.; Gomes, R.G.; Silva, M.G.; Thalhofer, J.L.; Silva, A.X.; Santos, R.F.G.

    2015-01-01

    Within a radiotherapy room, in addition to the primary beam, there is also secondary radiation due to the leakage of the accelerator head and the radiation scattering from room objects, patient and even the room's shielding itself, which is projected to protect external individuals disregarding its effects on the patient. This work aims to study the effect of concrete shielding wall over the patient, taking into account its contribution on equivalent doses. The MCNPX code was used to model the linear accelerator Varian 2100/2300 C/D operating at 18MeV, with MAX phantom representing the patient undergoing radiotherapy treatment for prostate cancer following Brazilian Institute of Cancer four-fields radiation application protocol (0°, 90°, 180° and 270°). Firstly, the treatment was patterned within a standard radiotherapy room, calculating the equivalent doses on patient's organs individually. In a second step, this treatment was modeled withdrawing the walls, floor and ceiling from the radiotherapy room, and then the equivalent doses calculated again. Comparing these results, it was found that the concrete has an average shielding contribution of around 20% in the equivalent dose on the patient's organs. (author)

  7. Re-establishment of the air kerma and ambient dose equivalent standards for the BIPM protection-level 60Co beam

    International Nuclear Information System (INIS)

    Kessler, C.; Roger, P.

    2005-07-01

    The air kerma and ambient dose equivalent standards for the protection-level 60 Co beam have been re-established following the repositioning of the irradiator and modifications to the beam. Details concerning the standards and the new uncertainty budgets are described in this report with their implications for dosimetry comparisons and calibrations. (authors)

  8. Calibration procedures of area monitors in terms of the Ambient Dose Equivalent H*(10), for gamma, x-ray radiation fields

    International Nuclear Information System (INIS)

    Dieguez Davila, L.E.

    1998-01-01

    In the present thesis procedures for calibrating portable survey meters in terms of the new ICRU quantities H*(10) ambient dose equivalent are discussed. Also the remendations of International Comission on Radiation Protection in their report ICRP 60 that inludes the operational magnitudes that the International Comission of Radiation Units proposed for calibrating area monitors

  9. Monte Carlo simulations of the secondary neutron ambient and effective dose equivalent rates from surface to suborbital altitudes and low Earth orbit.

    Science.gov (United States)

    El-Jaby, Samy; Richardson, Richard B

    2015-07-01

    Occupational exposures from ionizing radiation are currently regulated for airline travel (Earth orbit (∼300-400 km). Aircrew typically receive between 1 and 6 mSv of occupational dose annually, while aboard the International Space Station, the area radiation dose equivalent measured over just 168 days was 106 mSv at solar minimum conditions. It is anticipated that space tourism vehicles will reach suborbital altitudes of approximately 100 km and, therefore, the annual occupational dose to flight crew during repeated transits is expected to fall somewhere between those observed for aircrew and astronauts. Unfortunately, measurements of the radiation environment at the high altitudes reached by suborbital vehicles are sparse, and modelling efforts have been similarly limited. In this paper, preliminary MCNPX radiation transport code simulations are developed of the secondary neutron flux profile in air from surface altitudes up to low Earth orbit at solar minimum conditions and excluding the effects of spacecraft shielding. These secondary neutrons are produced by galactic cosmic radiation interacting with Earth's atmosphere and are among the sources of radiation that can pose a health risk. Associated estimates of the operational neutron ambient dose equivalent, used for radiation protection purposes, and the neutron effective dose equivalent that is typically used for estimates of stochastic health risks, are provided in air. Simulations show that the neutron radiation dose rates received at suborbital altitudes are comparable to those experienced by aircrew flying at 7 to 14 km. We also show that the total neutron dose rate tails off beyond the Pfotzer maximum on ascension from surface up to low Earth orbit. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  10. Experimental evaluation of neutron dose in radiotherapy patients: Which dose?

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Expósito, M., E-mail: mariateresa.romero@uab.cat; Domingo, C.; Ortega-Gelabert, O.; Gallego, S. [Grup de Recerca en Radiacions Ionizants (GRRI), Departament de Física, Universitat Autònoma de Barcelona, Bellaterra 08193 (Spain); Sánchez-Doblado, F. [Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla 41009 (Spain); Servicio de Radiofísica, Hospital Universitario Virgen Macarena, Sevilla 41009 (Spain)

    2016-01-15

    Purpose: The evaluation of peripheral dose has become a relevant issue recently, in particular, the contribution of secondary neutrons. However, after the revision of the Recommendations of the International Commission on Radiological Protection, there has been a lack of experimental procedure for its evaluation. Specifically, the problem comes from the replacement of organ dose equivalent by the organ-equivalent dose, being the latter “immeasurable” by definition. Therefore, dose equivalent has to be still used although it needs the calculation of the radiation quality factor Q, which depends on the unrestricted linear energy transfer, for the specific neutron irradiation conditions. On the other hand, equivalent dose is computed through the radiation weighting factor w{sub R}, which can be easily calculated using the continuous function provided by the recommendations. The aim of the paper is to compare the dose equivalent evaluated following the definition, that is, using Q, with the values obtained by replacing the quality factor with w{sub R}. Methods: Dose equivalents were estimated in selected points inside a phantom. Two types of medical environments were chosen for the irradiations: a photon- and a proton-therapy facility. For the estimation of dose equivalent, a poly-allyl-diglicol-carbonate-based neutron dosimeter was used for neutron fluence measurements and, additionally, Monte Carlo simulations were performed to obtain the energy spectrum of the fluence in each point. Results: The main contribution to dose equivalent comes from neutrons with energy higher than 0.1 MeV, even when they represent the smallest contribution in fluence. For this range of energy, the radiation quality factor and the radiation weighting factor are approximately equal. Then, dose equivalents evaluated using both factors are compatible, with differences below 12%. Conclusions: Quality factor can be replaced by the radiation weighting factor in the evaluation of dose

  11. Equivalent Dose Rate 1 Meter from Neuroendocrine Tumor Patients Exiting the Nuclear Medicine Department After Undergoing Imaging.

    Science.gov (United States)

    Zhang-Yin, Jules; Dirand, Anne-Sophie; Sasanelli, Myriam; Corrégé, Gwenaelle; Peudon, Aude; Kiffel, Thierry; Nataf, Valérie; Clerc, Jérôme; Montravers, Françoise; Talbot, Jean-Noël

    2017-08-01

    123 I-metaiodobenzylguanidine (MIBG) and 111 In-pentetrotide SPECT have been used for functional imaging of neuroendocrine tumors (NETs) for the last 2 decades. More recently, PET/CT imaging with 18 F-FDG, 18 F-fluorodihydroxyphenylalanine (FDOPA), and 68 Ga somatostatin-receptor ligands in NETs has been expanding. A literature search could find no direct measurements of the dose rate from NET patients exiting the nuclear medicine department after undergoing PET/CT with 18 F-FDOPA or 68 Ga-DOTATOC, a somatostatin analog. Methods: We measured the dose rates from 93 NET patients on leaving the department after undergoing PET/CT or SPECT/CT in our centers. In total, 103 paired measurements of equivalent dose rate at 1 m (EDR-1m) from the sternum and urinary bladder were obtained. The detector faced the sternum or bladder and was 1 m away from and directly in front of the patient. The practice for exiting the department differed according to whether the patient had been referred for PET/CT or for SPECT/CT. PET/CT patients were discharged after imaging, whereas SPECT/CT patients left the department earlier, just after radiopharmaceutical injection. Results: The median administered activity was 122 MBq in 53 68 Ga-DOTATOC PET/CT studies, 198 MBq in 15 18 F-FDOPA PET/CT studies, and 176 MBq in 13 18 F-FDG PET/CT studies. The corresponding median EDR-1m was 4.8, 9.5, and 8.8 μSv/h, respectively, facing the sternum, and 5.1, 10.1, and 9.5 μSv/h, respectively, facing the bladder. The median administered activity was 170 MBq in 12 111 In-pentetreotide SPECT/CT studies and 186 MBq in 10 123 I-MIBG SPECT/CT studies. The corresponding median EDR-1m was 9.4, and 4.9 μSv/h, respectively, at the level of the sternum, and 9.3 and 4.7 μSv/h, respectively, at the level of the bladder. The EDR-1m was less than 20 μSv/h in all patients. Thus, when exiting the nuclear medicine department, the NET patients injected with 68 Ga-DOTATOC or 123 I MIBG emitted an average EDR-1m roughly

  12. Acute non-stochastic effect of very low dose whole-body exposure, a thymidine equivalent serum factor

    International Nuclear Information System (INIS)

    Feinendegen, L.E.; Muehlensiepen, H.; Porschen, W.; Booz, J.

    1982-01-01

    Whole-body irradiation of mice causes the dose-dependent appearance of a humoral factor in blood serum which inhibits incorporation of 125-IUdR into tissue culture cells. This factor appears even at doses below 0.01 Gy gamma irradiation and thus is probably not related to cell death. Data are presented relating this humoral factor to thymidine. Since at low doses the target size for this effect was calculated to be the entire cell, a cellular effect is postulated linking the site of few primary absorption events, anywhere in the cell, with the cellular membrane, thus causing changes in membrane charge, structure and/or fluidity. This may lead to blocking thymidine acceptance by the cell, and thus would cause a pile-up of thymidine in the reutilization pathway in peripheral blood and would give rise to the observed effect. The effect appears as a temporary disturbance of the physiological equilibrium and should not be related at present to any cellular damage. The acute low-dose effect described has implications for the measurement of low-dose exposure by biological dosimeters and on basic research on membrane function. (author)

  13. Assessments of conversion coefficients between equivalent dose and accumulated activity using pre-dose scanning images of patients subjected to radioiodine treatment and the Fax/Egs4 computational model

    International Nuclear Information System (INIS)

    Lopes Filho, Ferdinand de J.; Vieira, Jose W.; Andrade Lima, Fernando R. de

    2008-01-01

    The radioiodine is a technique for treatment of thyroid cancer. In this technique, the patients are submitted to the incorporation of the radioactive substance sodium iodide (Na 131 I), which reacts with physiologically metastasis, thyroid tissue remains of and other organs and tissues of the human body. The locations of these reactions are known as areas of highest concentration, hipercaptured areas, hiperconcentrator areas, 'hot areas' or organ-sources and are viewed through images of nuclear medicine scan known as pre-dose (front and rear). To obtain these images, the patient receives, orally, a quantity of 131 I with low activity (± 74 MBq) and is positioned in the chamber of flicker. According to the attendance of hot areas shown in the images, the doctor determines the nuclear activity to be administered in treatment. This analysis is purely qualitative. In this study, the scanning images of pre-dose were adjusted to the dimensions of FAX voxel phantom, and the hot areas correspond to internal sources of the proposed model. Algorithms were developed to generate particles (photons and electrons) in these regions of the FAX. To estimate the coefficients of conversions between equivalent dose and accumulated activity in major radiosensitive organs, FAX and algorithms source were coupled to the Monte Carlo EGS4 code (Electron Gamma Shower, version 4). With these factors is possible to estimate the equivalent doses in the radiosensitive organs and tissues of patients as long as is know the activity administered and the half-life of organic sources. (author)

  14. Occupational dose assessment and national dose registry system in Iran

    International Nuclear Information System (INIS)

    Jafari-Zadeh, M.; Nazeri, F.; Hosseini-Pooya, S. M.; Taheri, M.; Gheshlaghi, F.; Kardan, M. R.; Babakhani, A.; Rastkhah, N.; Yousefi-Nejad, F.; Darabi, M.; Oruji, T.; Gholamali-Zadeh, Z.; Karimi-Diba, J.; Kazemi-Movahed, A. A.; Dashti-Pour, M. R.; Enferadi, A.; Jahanbakhshian, M. H.; Sadegh-Khani, M. R.

    2011-01-01

    This report presents status of external and internal dose assessment of workers and introducing the structure of National Dose Registry System of Iran (NDRSI). As well as types of individual dosemeters in use, techniques for internal dose assessment are presented. Results obtained from the International Atomic Energy Agency intercomparison programme on measurement of personal dose equivalent H p (10) and consistency of the measured doses with the delivered doses are shown. Also, implementation of dosimetry standards, establishment of quality management system, authorisation and approval procedure of dosimetry service providers are discussed. (authors)

  15. Determination of the equivalent dose in mixed neutron-gamma fields using spectrophotometric readout method: A study on NIRR-1 and Am-Be source

    International Nuclear Information System (INIS)

    Kassimu, A.A.; Akpa, T.C.; Jonah, S. A.; Mallam, S. P.

    2007-01-01

    Aliquots of alanine powder were irradiated with neutrons from a 5 5Ci-Am-Be source in the inner and outer channels of the Nigeria Research Reactor 1 (NIRR-1) in the Centre for Energy Research and Training, Zaria. The aim is to use the radiation-induced free radicals to determine the dose from the neutron sources. The irradiated amino acid was dissolved in a solution containing ferrous ammonium sulphate and xylenol orange in 0.05N H 2 SO 4 (FX-solution). The free radicals oxidize the Fe -2 to Fe -3 , which forms a complex with xylenol orange. The complex absorbs strongly at wavelength of 525nm. The absorbance was measured using CECIL CE 1020 spectrophotometer. Results show that the equivalent dose rate for the Am-Be source which is mainly from thermal neutrons component was 81.5 mSv/hr and that of the NIRR-1 which is mainly from the gamma ray component were 1.54 1011Sv/hr and 3.09 1010 Sv/hr for the inner and outer channels respectively. This shows that the equivalent dose rate in the inner channel is 5 times that of the outer channel. The estimated number of radicals producing a unit equivalent dose (Sv) is 3.33 1012 and 1.67 1012 for the inner and the outer channels respectively. This is in agreement with the predicted thermal neutron flux ratio of 2:1 for the channels in the reactor

  16. A new neutron dose equivalent rate meter with improved neutron energy response in terms of H*(10)

    International Nuclear Information System (INIS)

    Klett, A.; Maushart, R.; Burgkhardt, B.; Fieg, G.; Piesch, E.

    1994-01-01

    Conventional neutron dose rate meters make use of thermal neutron detectors such as 3 He counters located in the center of a moderator and absorber for thermal neutrons. The various commercial types used up to now have the disadvantage that the reading is extremely energy dependent exceeding a factor of up to 15. The need to improve the energy response and the sensitivity in the lower dose rate range resulted in joint cooperation between KfK and EG7G Berthold. On the basis of Monte-Carlo calculations and comprehensive calibrations with monoenergetic neutrons at the PTB Braunshweig, a new type of rem-counter has been optimized using a 10 cm x 4 cm diameter 3 He-counter. Both calculations and experiments resulted in a lower energy dependence within ±40% in the energy range 20 keV to 19 MeV. The commercially available dose rate meter of 25 cm diameter, with a weight below 10 kg and with a high neutron sensitivity of 3 counts per nSv has a dose rate range of 0.1 μSv/h - 100 mSv/h and low γ-sensitivity. With integrated electronics, this instrument is applicable for routine monitoring as well as for stationary monitoring of radiation fields near accelerators

  17. Different concentrations and volumes of p-phenylenediamine in pet. (equivalent doses) are associated with similar patch test outcomes

    DEFF Research Database (Denmark)

    Andersen, Flemming; Hamann, Carsten R; Andersen, Klaus E

    2018-01-01

    BACKGROUND: Concern about causing active sensitization when patch testing is performed with p-phenylenediamine (PPD) 1% pet. has led to a recommendation to use PPD 0.3% pet. as a potentially safer preparation. However, the dose per area of allergen delivered, and hence the risk of active sensitiz...

  18. Comparison of whole-body phantom designs to estimate organ equivalent neutron doses for secondary cancer risk assessment in proton therapy

    International Nuclear Information System (INIS)

    Moteabbed, Maryam; Drenkhahn, Robert; Paganetti, Harald; Geyer, Amy; Bolch, Wesley E

    2012-01-01

    Secondary neutron fluence created during proton therapy can be a significant source of radiation exposure in organs distant from the treatment site, especially in pediatric patients. Various published studies have used computational phantoms to estimate neutron equivalent doses in proton therapy. In these simulations, whole-body patient representations were applied considering either generic whole-body phantoms or generic age- and gender-dependent phantoms. No studies to date have reported using patient-specific geometry information. The purpose of this study was to estimate the effects of patient–phantom matching when using computational pediatric phantoms. To achieve this goal, three sets of phantoms, including different ages and genders, were compared to the patients’ whole-body CT. These sets consisted of pediatric age-specific reference, age-adjusted reference and anatomically sculpted phantoms. The neutron equivalent dose for a subset of out-of-field organs was calculated using the GEANT4 Monte Carlo toolkit, where proton fields were used to irradiate the cranium and the spine of all phantoms and the CT-segmented patient models. The maximum neutron equivalent dose per treatment absorbed dose was calculated and found to be on the order of 0 to 5 mSv Gy −1 . The relative dose difference between each phantom and their respective CT-segmented patient model for most organs showed a dependence on how close the phantom and patient heights were matched. The weight matching was found to have much smaller impact on the dose accuracy except for very heavy patients. Analysis of relative dose difference with respect to height difference suggested that phantom sculpting has a positive effect in terms of dose accuracy as long as the patient is close to the 50th percentile height and weight. Otherwise, the benefit of sculpting was masked by inherent uncertainties, i.e. variations in organ shapes, sizes and locations. Other sources of uncertainty included errors

  19. Estimation of low-level neutron dose-equivalent rate by using extrapolation method for a curie level Am–Be neutron source

    International Nuclear Information System (INIS)

    Li, Gang; Xu, Jiayun; Zhang, Jie

    2015-01-01

    Neutron radiation protection is an important research area because of the strong radiation biological effect of neutron field. The radiation dose of neutron is closely related to the neutron energy, and the connected relationship is a complex function of energy. For the low-level neutron radiation field (e.g. the Am–Be source), the commonly used commercial neutron dosimeter cannot always reflect the low-level dose rate, which is restricted by its own sensitivity limit and measuring range. In this paper, the intensity distribution of neutron field caused by a curie level Am–Be neutron source was investigated by measuring the count rates obtained through a 3 He proportional counter at different locations around the source. The results indicate that the count rates outside of the source room are negligible compared with the count rates measured in the source room. In the source room, 3 He proportional counter and neutron dosimeter were used to measure the count rates and dose rates respectively at different distances to the source. The results indicate that both the count rates and dose rates decrease exponentially with the increasing distance, and the dose rates measured by a commercial dosimeter are in good agreement with the results calculated by the Geant4 simulation within the inherent errors recommended by ICRP and IEC. Further studies presented in this paper indicate that the low-level neutron dose equivalent rates in the source room increase exponentially with the increasing low-energy neutron count rates when the source is lifted from the shield with different radiation intensities. Based on this relationship as well as the count rates measured at larger distance to the source, the dose rates can be calculated approximately by the extrapolation method. This principle can be used to estimate the low level neutron dose values in the source room which cannot be measured directly by a commercial dosimeter. - Highlights: • The scope of the affected area for

  20. Influence of length of interval between pulses in PDR brachytherapy (PDRBT on value of Biologically Equivalent Dose (BED in healthy tissues

    Directory of Open Access Journals (Sweden)

    Tomasz Piotrowski

    2010-07-01

    Full Text Available Purpose: Different PDR treatment schemas are used in clinical practice, however optimal length of interval between pulses still remains unclear. The aim of this work was to compare value of BED doses measured in surrounded healthy tissues according to different intervals between pulses in PDRBT. Influence of doses optimization on BED values was analyzed.Material and methods: Fifty-one patients treated in Greater Poland Cancer Centre were qualified for calculations.Calculations of doses were made in 51 patients with head and neck cancer, brain tumor, breast cancer, sarcoma, penis cancer and rectal cancer. Doses were calculated with the use of PLATO planning system in chosen critical points in surrounded healthy tissues. For all treatment plans the doses were compared using Biologically Equivalent Dose formula.Three interval lengths (1, 2 and 4 hours between pulses were chosen for calculations. For statistical analysis Friedman ANOVA test and Kendall ratio were used.Results: The median value of BED in chosen critical points in healthy tissues was statistically related to the length of interval between PDR pulses and decreased exponentially with 1 hour interval to 4 hours (Kendall = from 0.48 to 1.0; p = from 0.002 to 0.00001.Conclusions: Prolongation of intervals between pulses in PDR brachytherapy was connected with lower values of BED doses in healthy tissues. It seems that longer intervals between pulses reduced the risk of late complications, but also decreased the tumour control. Furthermore, optimization influenced the increase of doses in healthy tissues.

  1. SFACTOR: a computer code for calculating dose equivalent to a target organ per microcurie-day residence of a radionuclide in a source organ

    International Nuclear Information System (INIS)

    Dunning, D.E. Jr.; Pleasant, J.C.; Killough, G.G.

    1977-11-01

    A computer code SFACTOR was developed to estimate the average dose equivalent S (rem/μCi-day) to each of a specified list of target organs per microcurie-day residence of a radionuclide in source organs in man. Source and target organs of interest are specified in the input data stream, along with the nuclear decay information. The SFACTOR code computes components of the dose equivalent rate from each type of decay present for a particular radionuclide, including alpha, electron, and gamma radiation. For those transuranic isotopes which also decay by spontaneous fission, components of S from the resulting fission fragments, neutrons, betas, and gammas are included in the tabulation. Tabulations of all components of S are provided for an array of 22 source organs and 24 target organs for 52 radionuclides in an adult

  2. Estimation of annual dose equivalent (internal and external) for new thorium plant workers of IRE OSCOM, Orissa

    International Nuclear Information System (INIS)

    Vidya Sagar, D.; Tripathy, S.K.; Khan, A.H.; Maharana, L.N.

    2001-01-01

    In addition to thoron, thoron daughters and gamma radiation, the New Thorium Plant workers are exposed to long lived alpha emitters due to inhalation of thorium fine dust present in the working environment. Air samplers were used for measurement of thoron daughters and long lived alpha concentration. Each sample was counted for 3-4 hours for alpha activity and the long lived alpha concentration was calculated after taking the self absorption effect of the deposit on the filter paper into account. Internal dose of individual workers due to thoron daughter concentration and long lived alpha concentration was determined using time weighted factors. Based on the results, it is observed that contribution of thoron daughters, long lived alpha and external gamma is about 2 mSv /y, 1 mSv /y and 5 mSv/y, respectively, to total dose to the workers. (author)

  3. Estimation of activity of administered18F-fluorodeoxyglucose by measurement of the dose equivalent rate on the right temporal region of the head.

    Science.gov (United States)

    Sakaguchi, Kenta; Hosono, Makoto; Imamura, Tomomi; Takahara, Naomi; Hayashi, Misa; Yakushiji, Yuko; Ishii, Kazunari; Uto, Tatsuro; Murakami, Takamichi

    2016-12-01

    Positron emission tomography (PET) with 18 F-fluorodeoxyglucose (FDG) is now a routine procedure for the management of cancer patients. Intravenous administration of FDG is sometimes halted due to troubles. In such cases, estimations of the FDG dosage injected prior to halting administration may be helpful. We have established a method of estimating the activity of FDG to patients on the basis of the dose equivalent rate on the surface of the right temporal region of the head. The correlation of actual administered dosage with independent variables, such as the dose equivalent rate on the right temporal region of the head, age, sex, and body weight, was analyzed using multiple regression analysis to obtain linear, quadratic, and cubic regression equations. When entering independent variables, the cubic regression equation could be used to estimate an administered dosage with an accuracy of ±10 % for 62 % of all patients and ±20 % for 90 % of all patients. We conclude that this method is useful for estimating the administered dosage from the dose equivalent rate on the temporal region of the head.

  4. Determination of the neutron and photon dose equivalent at work places in nuclear facilities of Sweden. An SSI - EURADOS comparison exercise. Part 2: Evaluation

    International Nuclear Information System (INIS)

    Bartlett, D.; Drake, P.; Lindborg, L.; Klein, H.; Schmitz, Th.; Tichy, M.

    1999-06-01

    Various mixed neutron-photon fields at workplaces in the containment of pressurised water reactors and in the vicinity of transport containers with spent fuel elements were investigated with spectrometers and dosimeters. The spectral neutron fluences evaluated from measurements with multisphere systems were recommended to be used for the calculation of dosimetric reference values for comparison with the readings of the dosemeters applied simultaneously. It turned out that most of the moderator based area dosemeters overestimated, while the TEPC systems generally underestimated the ambient dose equivalent (DE) values of the rather soft neutron fields encountered at these workplaces. The discrepancies can, however, be explained on the basis of energy dependent responses of the instruments used. The ambient DE values obtained with recently developed area dosemeters based on superheated drop detectors and with track etch based personal dosemeters on phantoms, however, were in satisfying agreement with the reference data. Sets of personal dosemeters simultaneously irradiated on a phantom allowed to roughly estimate the directional dependence of the neutron fluence. Hence, personal and limiting dose equivalent quantities could also be calculated. The personal and ambient DE values were always conservative estimates of the limiting quantities. Unexpectedly, discrepancies were observed for photon DE data measured with GM counters and TEPC systems. The up to 50 % higher readings of the GM counters may be explained by a considerable contribution of high energy photons to the total photon dose equivalent, but photon spectrometry is necessary for final clarification

  5. Determination of the neutron and photon dose equivalent at work places in nuclear facilities of Sweden. An SSI - EURADOS comparison exercise. Part 2: Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Bartlett, D. [National Radiological Protection Board, Chilton (United Kingdom); Drake, P. [Vattenfall AB, Vaeroebacka (Sweden); Lindborg, L. [Swedish Radiation Protection Inst., Stockholm (Sweden); Klein, H. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Schmitz, Th. [Forschungszentrum Juelich GmbH, Juelich (Germany); Tichy, M

    1999-06-01

    Various mixed neutron-photon fields at workplaces in the containment of pressurised water reactors and in the vicinity of transport containers with spent fuel elements were investigated with spectrometers and dosimeters. The spectral neutron fluences evaluated from measurements with multisphere systems were recommended to be used for the calculation of dosimetric reference values for comparison with the readings of the dosemeters applied simultaneously. It turned out that most of the moderator based area dosemeters overestimated, while the TEPC systems generally underestimated the ambient dose equivalent (DE) values of the rather soft neutron fields encountered at these workplaces. The discrepancies can, however, be explained on the basis of energy dependent responses of the instruments used. The ambient DE values obtained with recently developed area dosemeters based on superheated drop detectors and with track etch based personal dosemeters on phantoms, however, were in satisfying agreement with the reference data. Sets of personal dosemeters simultaneously irradiated on a phantom allowed to roughly estimate the directional dependence of the neutron fluence. Hence, personal and limiting dose equivalent quantities could also be calculated. The personal and ambient DE values were always conservative estimates of the limiting quantities. Unexpectedly, discrepancies were observed for photon DE data measured with GM counters and TEPC systems. The up to 50 % higher readings of the GM counters may be explained by a considerable contribution of high energy photons to the total photon dose equivalent, but photon spectrometry is necessary for final clarification.

  6. On the applicability of the leading edge method to obtain equivalent doses in OSL dating and dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Woda, C. [Helmholtz Zentrum Muenchen - German Research Center for Environmental Health, Institute of Radiation Protection, D-85764 Neuherberg (Germany)], E-mail: clemens.woda@helmholtz-muenchen.de; Fuchs, M. [Lehrstuhl Geomorphologie, Universitaet Bayreuth, D-95440 Bayreuth (Germany)

    2008-01-15

    The applicability of an objective methodology for dose distribution analysis proposed by Lepper and McKeever [2002. An objective methodology for dose distribution analysis. Radiat. Prot. Dosimetry 101 (1-4), 349-352] to samples, where available material only allows the measurement of a small number of aliquots, is investigated. The basis for the study are artificially and naturally insufficiently bleached samples for which a large number (>90) of aliquots were measured. Smaller sets of aliquots are then randomly drawn from this pool and a Gaussian function fitted to the rising limb of the dose distribution. It is found that when the method is based on a three-parameter fit, it is no longer applicable when the number of aliquots is significantly reduced. The percentage of successful fits for data sets made of only 20 aliquots was on average below 20%. In addition for data sets composed of 40 to 60 aliquots, palaeodoses obtained from fitting spread over a large dose range and showed a strongly asymmetric distribution. A significant improvement could be achieved by fixing the center of the Gaussian function to the mode D{sub E} bin and only fitting a two-parameter function to the data sets. With this approach an 80% change of successful fitting could be achieved even when using dose distributions constructed from only 20 to 30 aliquots. The median of the palaeodose distributions was approximately independent of the number of aliquots used. The modified method is then applied to samples from a sedimentary record in the northern Oman mountain range and the results compared with the method proposed by Fuchs and Lang [2001. OSL dating of coarse-grain fluvial quartz using single-aliquot protocols on sediments from NE Peleponnese, Greece. Quat. Sci. Rev. 20, 783-787]. It is concluded that the leading edge method proposed by Lepper and McKeever can be useful to derive D{sub E}'s from insufficiently bleached sediments even for a small number of aliquots if the Gaussian

  7. Image processing techniques revealing the relationship between the field-measured ambient gamma dose equivalent rate and geological conditions at a granitic area, Velence Mountains, Hungary

    Science.gov (United States)

    Beltran Torres, Silvana; Petrik, Attila; Zsuzsanna Szabó, Katalin; Jordan, Gyozo; Szabó, Csaba

    2017-04-01

    In order to estimate the annual dose that the public receive from natural radioactivity, the identification of the potential risk areas is required which, in turn, necessitates understanding the relationship between the spatial distribution of natural radioactivity and the geogenic risk factors (e.g., rock types, dykes, faults, soil conditions, etc.). A detailed spatial analysis of ambient gamma dose equivalent rate was performed in the western side of Velence Mountains, the largest outcropped granitic area in Hungary. In order to assess the role of local geology in the spatial distribution of ambient gamma dose rates, field measurements were carried out at ground level at 300 sites along a 250 m x 250 m regular grid in a total surface of 14.7 km2. Digital image processing methods were applied to identify anomalies, heterogeneities and spatial patterns in the measured gamma dose rates, including local maxima and minima determination, digital cross sections, gradient magnitude and gradient direction, second derivative profile curvature, local variability, lineament density, 2D autocorrelation and directional variogram analyses. Statistical inference showed that different gamma dose rate levels are associated with the rock types (i.e., Carboniferous granite, Pleistocene colluvial, proluvial, deluvial sediments and talus, and Pannonian sand and pebble), with the highest level on the Carboniferous granite including outlying values. Moreover, digital image processing revealed that linear gamma dose rate spatial features are parallel to the SW-NE dyke system and possibly to the NW-SE main fractures. The results of this study underline the importance of understanding the role of geogenic risk factors influencing the ambient gamma dose rate received by public. The study also demonstrates the power of the image processing techniques for the identification of spatial pattern in field-measured geogenic radiation.

  8. SU-E-T-102: Determination of Dose Distributions and Water-Equivalence of MAGIC-F Polymer Gel for 60Co and 192Ir Brachytherapy Sources

    Energy Technology Data Exchange (ETDEWEB)

    Quevedo, A; Nicolucci, P [University of Sao Paulo, Ribeirao Preto, SP (Brazil)

    2014-06-01

    Purpose: Analyse the water-equivalence of MAGIC-f polymer gel for {sup 60}Co and {sup 192}Ir clinical brachytherapy sources, through dose distributions simulated with PENELOPE Monte Carlo code. Methods: The real geometry of {sup 60} (BEBIG, modelo Co0.A86) and {sup 192}192Ir (Varian, model GammaMed Plus) clinical brachytherapy sources were modelled on PENELOPE Monte Carlo simulation code. The most probable emission lines of photons were used for both sources: 17 emission lines for {sup 192}Ir and 12 lines for {sup 60}. The dose distributions were obtained in a cubic water or gel homogeneous phantom (30 × 30 × 30 cm{sup 3}), with the source positioned in the middle of the phantom. In all cases the number of simulation showers remained constant at 10{sup 9} particles. A specific material for gel was constructed in PENELOPE using weight fraction components of MAGIC-f: wH = 0,1062, wC = 0,0751, wN = 0,0139, wO = 0,8021, wS = 2,58×10{sup −6} e wCu = 5,08 × 10{sup −6}. The voxel size in the dose distributions was 0.6 mm. Dose distribution maps on the longitudinal and radial direction through the centre of the source were used to analyse the water-equivalence of MAGIC-f. Results: For the {sup 60} source, the maximum diferences in relative doses obtained in the gel and water were 0,65% and 1,90%, for radial and longitudinal direction, respectively. For {sup 192}Ir, the maximum difereces in relative doses were 0,30% and 1,05%, for radial and longitudinal direction, respectively. The materials equivalence can also be verified through the effective atomic number and density of each material: Zef-MAGIC-f = 7,07 e .MAGIC-f = 1,060 g/cm{sup 3} and Zef-water = 7,22. Conclusion: The results showed that MAGIC-f is water equivalent, consequently being suitable to simulate soft tissue, for Cobalt and Iridium energies. Hence, gel can be used as a dosimeter in clinical applications. Further investigation to its use in a clinical protocol is needed.

  9. Measurement of the ambient gamma dose equivalent and kerma from the small 252Cf source at 1 meter and the small 60Co source at 2 meters

    Energy Technology Data Exchange (ETDEWEB)

    Carl, W. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-07-30

    NASA Langley Research Center requested a measurement and determination of the ambient gamma dose equivalent rate and kerma at 100 cm from the 252Cf source and determination of the ambient gamma dose equivalent rate and kerma at 200 cm from the 60Co source for the Radiation Budget Instrument Experiment (Rad-X). An Exradin A6 ion chamber with Shonka air-equivalent plastic walls in combination with a Supermax electrometer were used to measure the exposure rate and free-in-air kerma rate of the two sources at the requested distances. The measured gamma exposure, kerma, and dose equivalent rates are tabulated.

  10. Calculation of exit dose for conformal and dynamically‐wedged fields, based on water‐equivalent path length measured with an amorphous silicon electronic portal imaging device

    Science.gov (United States)

    Glegg, Martin; Metwaly, Mohamed; Currie, Garry; Elliott, Alex

    2011-01-01

    In this study, we use the quadratic calibration method (QCM), in which an EPID image is converted into a matrix of equivalent path lengths (EPLs) and, therefore, exit doses, so as to model doses in conformal and enhanced dynamic wedge (EDW) fields. The QCM involves acquiring series of EPID images at a reference field size for different thicknesses of homogeneous solid water blocks. From these, a set of coefficients is established that is used to compute the EPL of any other irradiated material. To determine the EPL, the irradiated area must be known in order to establish the appropriate scatter correction. A method was devised for the automatic calculation of areas from the EPID image that facilitated the calculation of EPL for any field and exit dose. For EDW fields, the fitting coefficients were modified by utilizing the linac manufacturer's golden segmented treatment tables (GSTT) methodology and MU fraction model. The nonlinear response of the EPL with lower monitor units (MUs) was investigated and slight modification of the algorithm performed to account for this. The method permits 2D dose distributions at the exit of phantom or patient to be generated by relating the EPL with an appropriate depth dose table. The results indicate that the inclusion of MU correction improved the EPL determination. The irradiated field areas can be accurately determined from EPID images to within ± 1% uncertainty. Cross‐plane profiles and 2D dose distributions of EPID predicted doses were compared with those calculated with the Eclipse treatment planning system (TPS) and those measured directly with MapCHECK 2 device. Comparison of the 2D EPID dose maps to those from TPS and MapCHECK shows that more than 90% of all points passed the gamma index acceptance criteria of 3% dose difference and 3 mm distance to agreement (DTA), for both conformal and EDW study cases. We conclude that the EPID QCM is an accurate and convenient method for in vivo dosimetry and may, therefore

  11. Assessment of ambient dose equivalent rate performance of an automatic survey meter as an instrument to quantify the presence of radiation in soils

    CERN Document Server

    Yoshimura, E M; Okuno, E

    2002-01-01

    Those who work in radiation protection are faced with various quantities that were created to account for the effects of ionizing radiation in the human body. As far as the experimental point of view is concerned, each available equipment is planned to measure a distinct quantity, for a specific radiation protection application, and it is not always clear which one it is. This paper shows a series of tests, planned and applied to a portable gamma ray spectrometer, in order to assure that the monitoring low dose levels of radiation with it is reliable. The equipment is fully automated and does not allow modifications of the conversion factors from counts to ambient dose equivalent. It is therefore necessary to assure that the values provided by the equipment are correct and refer to the actual situation one expects to find in practice. The system is based on an NaI(Tl) scintillation detector, mounted with its electronics in a portable case, suitable for field measurements. It measures ambient dose equivalent r...

  12. INREM II: a computer implementation of recent models for estimating the dose equivalent to organs of man from an inhaled or ingested radionuclide

    International Nuclear Information System (INIS)

    Killough, G.G.; Dunning, D.E. Jr.; Pleasant, J.C.

    1978-01-01

    This report describes a computer code, INREM II, which calculates the internal radiation dose equivalent to organs of man which results from the intake of a radionuclide by inhalation or ingestion. Deposition and removal of radioactivity from the respiratory tract is represented by the ICRP Task Group Lung Model. A four-segment catenary model of the GI tract is used to estimate movement of radioactive material that is ingested or swallowed after being cleared from the respiratory tract. Retention of radioactivity in other organs is specified by linear combinations of decaying exponential functions. The formation and decay of radioactive daughters is treated explicitly, with each radionuclide species in the chain having its own uptake and retention parameters, as supplied by the user. The dose equivalent to a target organ is computed as the sum of contributions from each source organ in which radioactivity is assumed to be situated. This calculation utilizes a matrix of S-factors (rem/μCi-day) supplied by the user for the particular choice of source and target organs. Output permits the evaluation of crossfire components of dose when penetrating radiations are present. INREM II is coded in FORTRAN IV and has been compiled and executed on an IBM-360 computer

  13. Bio-equivalent doses of recombinant HCG and recombinant LH during ovarian stimulation result in similar oestradiol output

    DEFF Research Database (Denmark)

    Alsbjerg, Birgit; Elbaek, Helle Olesen; Laursen, Rita Jakubcionyte

    2017-01-01

    In nature, HCG is secreted by the implanting embryo from peri-implantation and onwards. In contrast, LH is mandatory for steroidogenesis and follicular development during the follicular phase, working in synergy with FSH. Moreover, LH is mandatory for the function of the corpus luteum. Although LH...... and HCG bind to the same receptor, significant molecular, structural and functional differences exist, inducing differences in bioactivity. This randomized controlled study compared the effect of recombinant FSH stimulation combined with daily either micro-dose recombinant HCG or recombinant LH...... oestradiol level in the HCG supplemented group was 8662 pmol/l versus 9203 pmol/l in the recombinant LH supplemented group; therefore, no significant difference was found. Moreover, no differences were observed in the number of oocytes retrieved or in the live birth rate. We conclude that recombinant HCG...

  14. Measurement of extrapolation curves for the secondary pattern of beta radiation Nr. 86 calibrated in rapidity of absorbed dose for tissue equivalent by the Physikalisch Technische Bundesanstalt

    International Nuclear Information System (INIS)

    Alvarez R, J.T.

    1988-10-01

    The following report has as objective to present the obtained results of measuring - with a camera of extrapolation of variable electrodes (CE) - the dose speed absorbed in equivalent fabric given by the group of sources of the secondary pattern of radiation Beta Nr. 86, (PSB), and to compare this results with those presented by the calibration certificates that accompany the PSB extended by the primary laboratory Physikalisch Technische Bundesanstalt, (PTB), of the R.F.A. as well as the uncertainties associated to the measure process. (Author)

  15. Measurements of LET distribution and dose equivalent onboard the Space Shuttle IML-2 (STS-65) and S/MM#4 (STS-79)

    Science.gov (United States)

    Hayashi, T.; Doke, T.; Kikuchi, J.; Sakaguchi, T.; Takeuchi, R.; Takashima, T.; Kobayashi, M.; Terasawa, K.; Takahashi, K.; Watanabe, A.; hide

    1997-01-01

    Space radiation dosimetry measurements have been made onboard the Space Shuttle STS-65 in the Second International Microgravity Laboratory (IML-2: 28.5 degrees x 300 km: 14.68 days) and the STS-79 in the 4th Shuttle MIR mission (S/MM#4: 51.6 degrees x 300-400km: 10.2 days). In these measurements, three kinds of detectors were used; one is a newly developed active detector telescope called "Real-time Radiation Monitoring Device (RRMD-I for IML-2 and RRMD-II with improved triggering system for S/MM#4)" utilizing silicon semi-conductor detectors and the other detectors are conventional passive detectors of thermoluminescence dosimeters (TLDs) and CR-39 plastic track detectors. The main contribution to dose equivalent for particles with LET > 5.0 keV/micrometer (IML-2) and LET > 3.5 keV/micrometer (S/MM#4) is seen to be due to galactic cosmic rays (GCRs) and the contribution of the South Atlantic Anomaly (SAA) is less than 5% (IML-2: 28.5 degrees x 300 km) and 15% (S/MM#4: 51.6 degrees x 400 km) in the above RRMD LET detection conditions. For the whole LET range (> 0.2 kev/micrometer) obtained by TLDs and CR-39 in these two typical orbits (a small inclination x low altitude and a large inclination x high altitude), absorbed dose rates range from 94 to 114 microGy/day, dose equivalent rates from 186 to 207 microSv/day and average quality factors from 1.82 to 2.00 depending on the locations and directions of detectors inside the Spacelab at the highly protected IML-2 orbit (28.5 degrees x 300 km), and also, absorbed dose rates range from 290 to 367 microGy/day, dose equivalent rates from 582 to 651 microSv/day and average quality factors from 1.78 to 2.01 depending on the dosimeter packages around the RRMD-II "Detector Unit" at the S/MM#4 orbit (5l.6 degrees x 400km). In general, it is seen that absorbed doses depend on the orbit altitude (SAA trapped particles contribution dominant) and dose equivalents on the orbit inclination (GCR contribution dominant). The LET

  16. Development of a computational model for the calculation of neutron dose equivalent in laminated primary barriers of radiotherapy rooms

    International Nuclear Information System (INIS)

    Rezende, Gabriel Fonseca da Silva

    2015-01-01

    Many radiotherapy centers acquire 15 and 18 MV linear accelerators to perform more effective treatments for deep tumors. However, the acquisition of these equipment must be accompanied by an additional care in shielding planning of the rooms that will house them. In cases where space is restricted, it is common to find primary barriers made of concrete and metal. The drawback of this type of barrier is the photoneutron emission when high energy photons (e.g. 15 and 18 MV spectra) interact with the metallic material of the barrier. The emission of these particles constitutes a problem of radiation protection inside and outside of radiotherapy rooms, which should be properly assessed. A recent work has shown that the current model underestimate the dose of neutrons outside the treatment rooms. In this work, a computational model for the aforementioned problem was created from Monte Carlo Simulations and Artificial Intelligence. The developed model was composed by three neural networks, each being formed of a pair of material and spectrum: Pb18, Pb15 and Fe18. In a direct comparison with the McGinley method, the Pb18 network exhibited the best responses for approximately 78% of the cases tested; the Pb15 network showed better results for 100% of the tested cases, while the Fe18 network produced better answers to 94% of the tested cases. Thus, the computational model composed by the three networks has shown more consistent results than McGinley method. (author)

  17. Calculation of conversion coefficients for air kerma to ambient dose equivalent using transmitted spectra of megavoltage X-rays through concrete.

    Science.gov (United States)

    Cordeiro, T P V; Silva, A X

    2012-12-01

    With the fast advancement of technology, (60)Co teletherapy units are largely being replaced with medical linear accelerators. In most cases, the linear accelerator tends to be installed in the same room in which the (60)Co teletherapy unit was previously placed. If in-depth structural remodelling is out of the question, high-density concrete is usually used to improve shielding against primary, scatter and leakage radiation originating in the new equipment. This work presents a study based on Monte Carlo simulations of the transmission of some clinical photon spectra (from 6, 10, 15, 18 and 25 MV accelerators) through concrete, considering two different densities. Concrete walls with thickness ranging from 0.70 to 2.0 m were irradiated with 30 cm×30 cm primary beam spectra. The results show that the thickness of the barrier decreases up to ∼65 % when barite (high-density concrete) is used instead of ordinary concrete. The average energies of primary and transmitted beam spectra were also calculated. In addition, conversion coefficients from air kerma to ambient dose equivalent, H*(d)/K(air), and air kerma to effective dose, E/K(air), for photon spectra from the transmitted spectra were calculated and compared. The results suggest that the 10-mm depth is not the best choice to represent the effective dose.

  18. Doses from radiation exposure

    CERN Document Server

    Menzel, H G

    2012-01-01

    Practical implementation of the International Commission on Radiological Protection's (ICRP) system of protection requires the availability of appropriate methods and data. The work of Committee 2 is concerned with the development of reference data and methods for the assessment of internal and external radiation exposure of workers and members of the public. This involves the development of reference biokinetic and dosimetric models, reference anatomical models of the human body, and reference anatomical and physiological data. Following ICRP's 2007 Recommendations, Committee 2 has focused on the provision of new reference dose coefficients for external and internal exposure. As well as specifying changes to the radiation and tissue weighting factors used in the calculation of protection quantities, the 2007 Recommendations introduced the use of reference anatomical phantoms based on medical imaging data, requiring explicit sex averaging of male and female organ-equivalent doses in the calculation of effecti...

  19. An equivalence study comparing nitrous oxide and oxygen with low-dose sevoflurane and oxygen as inhalation sedation agents in dentistry for adults.

    Science.gov (United States)

    Allen, M; Thompson, S

    2014-11-01

    The aim of this study was to examine whether sevoflurane in oxygen was equivalent to near equipotent concentrations of nitrous oxide in oxygen when used as an inhalation sedation agent in terms of patient and user acceptability. Forty anxious dental patients referred to the sedation suite at Cardiff University School of Dentistry received either nitrous oxide to a maximum concentration of 40% or sevoflurane to a maximum concentration of 0.3% for a routine maxillary plastic restoration with articaine infiltration local analgesia. The inhalation sedation agent to be administered was chosen by a random number allocator. Measurements of blood pressure, oxygen saturation, heart rate, respiratory rate and bispectral index were recorded every 5 minutes. At the end of the treatment episode the patient, the operator and an observer who was unaware of the agent used, recorded their impressions about the episode by completing questionnaires. In the doses used in this study, sevoflurane was found to be as effective as an inhalation sedation agent as the standard dose of nitrous oxide used in normal inhalation sedation in the treatment of adult anxious dental patients. Sevoflurane in low concentrations is equivalent in effect to near equipotent concentrations of nitrous oxide. This would suggest that further research, perhaps with slightly higher concentrations of sevoflurane, is needed. If sevoflurane was shown to be acceptable at slightly higher concentrations, there is scope to explore the development of equipment specifically designed to deliver sevoflurane as an inhalation sedation agent in future.

  20. Calculation Monte Carlo equivalent dose to organs in a treatment of prostate with Brachytherapy of high rate; Calculo Monte Carlo de dosis equivalente a organos en un tratamiento de prostata con braquiterapia de alta tasa

    Energy Technology Data Exchange (ETDEWEB)

    Candela-Juan, C.; Vijande, J.; Granero, D.; Ballester, F.; Perez-Calatayud, J.; Rivard, M. J.

    2013-07-01

    The objective of this study was to obtain equivalent dose to radiosensitive organs when applies brachytherapy high dose (HDR) with sources of 60 Co or 192 Go to a localized carcinoma of the prostate. The results are compared with those reported in the literature on treatment with protons and intensity modulated (IMRT) radiation therapy. (Author)

  1. Reduced recanalization rates of the great saphenous vein after endovenous laser treatment with increased energy dosing: definition of a threshold for the endovenous fluence equivalent.

    Science.gov (United States)

    Proebstle, Thomas Michael; Moehler, Thomas; Herdemann, Sylvia

    2006-10-01

    Recent reports indicated a correlation between the amount of energy released during endovenous laser treatment (ELT) of the great saphenous vein (GSV) and the success and durability of the procedure. Our objective was to analyze the influence of increased energy dosing on immediate occlusion and recanalization rates after ELT of the GSV. GSVs were treated with either 15 or 30 W of laser power by using a 940-nm diode laser with continuous fiber pullback and tumescent local anesthesia. Patients were followed up prospectively with duplex ultrasonography at day 1 and at 1, 3, 6, and 12 months. A total of 114 GSVs were treated with 15 W, and 149 GSVs were treated with 30 W. The average endovenous fluence equivalents were 12.8 +/- 5.1 J/cm2 and 35.1 +/- 15.6 J/cm2, respectively. GSV occlusion rates according to the method of Kaplan and Meier for the 15- and 30-W groups were 95.6% and 100%, respectively, at day 1, 90.4% and 100% at 3 months, and 82.7% and 97.0% at 12 months after ELT (log-rank; P = .001). An endovenous fluence equivalent exceeding 20 J/cm2 was associated with durable GSV occlusion after 12 months' follow-up, thus suggesting a schedule for dosing of laser energy with respect to the vein diameter. Higher dosing of laser energy shows a 100% immediate success rate and a significantly reduced recanalization rate during 12 months' follow-up.

  2. Equivalence of a single dose (1200 mg) compared to a three-time a day dose (400 mg) of chondroitin 4&6 sulfate in patients with knee osteoarthritis. Results of a randomized double blind placebo controlled study.

    Science.gov (United States)

    Zegels, B; Crozes, P; Uebelhart, D; Bruyère, O; Reginster, J Y

    2013-01-01

    Evaluation of the efficacy and safety of a single oral dose of a 1200 mg sachet of chondroitin 4&6 sulfate (CS 1200) vs three daily capsules of chondroitin 4&6 sulfate 400 mg (CS 3*400) (equivalence study) and vs placebo (superiority study) during 3 months, in patients with knee osteoarthritis (OA). Comparative, double-blind, randomized, multicenter study, including 353 patients of both genders over 45 years with knee OA. Minimum inclusion criteria were a Lequesne index (LI) ≥ 7 and pain ≥ 40 mm on a visual analogue scale (VAS). LI and VAS were assessed at baseline and after 1-3 months. Equivalence between CS was tested using the per-protocol procedure and superiority of CS vs placebo was tested using an intent-to-treat procedure. After 3 months of follow-up, no significant difference was demonstrated between the oral daily single dose of CS 1200 formulation and the three daily capsules of CS 400. Patients treated with CS 1200 or CS 3*400 were significantly improved compared to placebo after 3 months of follow-up in terms of LI (security and tolerability was observed between the three groups. This study suggests that a daily administration of an oral sachet of 1200 mg of chondroitin 4&6 sulfate allows a significant clinical improvement compared to a placebo, and a similar improvement when compared to a regimen of three daily capsules of 400 mg of the same active ingredient. Copyright © 2012 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  3. When is a dose not a dose?

    International Nuclear Information System (INIS)

    Green, Patrick

    1992-01-01

    There is confusion over radiation dose limits between the International Commission on Radiological Protection, the National Radiological Protection Board and the Ministry of Agriculture, Fisheries and Food (MAFF), reports a Friends of the Earth's radiation campaigner. MAFF is suggesting the inadequate ICRP public dose limit does not apply to public exposures which arise from environmental contamination from past radioactive discharges. (author)

  4. Organ or tissue doses, effective dose and collective effective dose from X-ray diagnosis, in Japan

    International Nuclear Information System (INIS)

    Murayama, Takashi; Nishizawa, Kanae; Noda, Yutaka; Kumamoto, Yoshikazu; Iwai, Kazuo.

    1996-01-01

    Effective doses and collective effective doses from X-ray diagnostic examinations were calculated on the basis of the frequency of examinations estimated by a nationwide survey and the organ or tissue doses experimentally determined. The average organ or tissue doses were determined with thermoluminescence dosimeters put at various sites of organs or tissues in an adult and a child phantom. Effective doses (effective dose equivalents) were calculated as the sum of the weighted equivalent doses in all the organs or tissues of the body. As the examples of results, the effective doses per radiographic examination were approximately 7 mGy for male, and 9 mGy for female angiocardiography, and about 3 mGy for barium meal. Annual collective effective dose from X-ray diagnostic examinations in 1986 were about 104 x 10 3 person Sv from radiography and 118 x 10 3 person Sv from fluoroscopy, with the total of 222 x 10 3 person Sv. (author)

  5. Calculation by the Monte Carlo method of the equivalent dose received by a human fetus from gamma sources localized in the gastrointestinal tract

    International Nuclear Information System (INIS)

    Segreto, V.S.A.

    1979-01-01

    New uterus positions are proposed and worked out in detail to evaluate the exposure of the human fetus to radiation originated in the gastrointestinal-tract during the pregnancy period. In our evaluation each organ in the gastrointestinal-tract namely stomach, small intestine, transverse colon, ascendent colon, descendent colon, sigmoid and rectum was individually considered. Changes in the position of each of these organs were studied as a function of the uterus growth. There were evaluated cases in which the uterus was in three, six and nine month pregnancy for photon energies of 0.02, 0.05, 0.10, 0.50 and 4 MeV. The average equivalent doses (H) of the uterus, in the uterine wall and in each one of the twelve compartiments which we considered as sub-divisions of the uterus were also determined and discussed. (Auhor) [pt

  6. Analysis simulation of tectonic earthquake impact to the lifetime of radioactive waste container and equivalent dose rate predication in Yucca Mountain geologic repository, Nevada test site, USA

    International Nuclear Information System (INIS)

    Ko, I.S.; Imardjoko, Y.U.; Karnawati, Dwikorita

    2003-01-01

    US policy not to recycle her spent nuclear fuels brings consequence to provide a nuclear waste repository site Yucca Mountain in Nevada, USA, considered the proper one. High-level radioactive waste to be placed into containers and then will be buried in three hundred meter underground tunnels. Tectonic earthquake is the main factor causing container's damage. Goldsim version 6.04.007 simulates mechanism of container's damage due to a great devastating impact load, the collapse of the tunnels. Radionuclide inventories included are U-234, C-14, Tc-99, I-129, Se-79, Pa-231, Np-237, Pu-242, and Pu-239. Simulation carried out in 100,000 years time span. The research goals are: 1). Estimating tunnels stan-up time, and 2). Predicting the equivalent dose rate contributed by the included radionuclides to the human due to radioactive polluted drinking water intake. (author)

  7. Estimates of internal dose equivalent to 22 target organs for radionuclides occurring in routine releases from nuclear fuel-cycle facilities. Vol. 1

    International Nuclear Information System (INIS)

    Killough, G.G.; Dunning, D.E. Jr.; Bernard, S.R.; Pleasant, J.C.

    1978-01-01

    This report is the first of a two-volume tabulation of internal radiation dose conversion factors for man for radionuclides of interest in environmental assessments of light-water-reactor fuel cycles. This volume treats 68 radionuclides, all of mass number less than 150. Intake by inhalation and ingestion is considered. In the former case, the ICRP Task Group Lung Model has been used to simulate the behavior of particulate matter in the respiratory tract. Results corresponding to activity median aerodynamic diameters (AMAD) of 0.3, 1.0, and 5.0 μm are given. The GI tract has been represented by a four-segment catenary model with exponential transfer of radioactivity from one segment to the next. Retention of radionuclides in other organs was characterized by linear combinations of decaying exponential functions. Dose equivalent per microcurie intake of each parent nuclide is given for 22 target organs with contributions from specified source organs plus surplus activity in the rest of the body. Cross irradiation due to penetrating radiations has also been considered in the calculations

  8. Recommendations on good practices in the field of workers radiation protection in the perspective of lowering of the legal limitation of the equivalent dose for the eyes lens

    International Nuclear Information System (INIS)

    2015-01-01

    As international bodies (ICRP, IAEA) have proposed or accepted a reduction of the equivalent dose limitation for the eyes crystalline lens for workers in situations of planned exposures, this report by the IRSN is an answer to a request made by the ASN for an opinion on expected good practices in terms of radiation protection of workers, particularly within the framework of interventional radiology and in operating rooms where these interventional actions occur. After having recalled the historical context and outlined the differences between different published data, the report identifies professional activities at risk (general aspects, case of interventional radiology, case of brachytherapy, nuclear medicine and medical research, case of industrial activities). It describes the characteristics of good practices in radiation protection in these different environments (general, interventional radiology, and so on) in order to protect workers or to optimise individual exposure. The next part addresses the issue of dose control: choice of dosimetric quantity, ways to assess lens exposure. A set of recommendations is then proposed

  9. Evolution of radon dose evaluation

    Directory of Open Access Journals (Sweden)

    Fujimoto Kenzo

    2004-01-01

    Full Text Available The historical change of radon dose evaluation is reviewed based on the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR reports. Since 1955, radon has been recognized as one of the important sources of exposure of the general public. However, it was not really understood that radon is the largest dose contributor until 1977 when a new concept of effective dose equivalent was introduced by International Commission on Radiological Protection. In 1982, the dose concept was also adapted by UNSCEAR and evaluated per caput dose from natural radiation. Many researches have been carried out since then. However, lots of questions have remained open in radon problems, such as the radiation weighting factor of 20 for alpha rays and the large discrepancy of risk estimation among dosimetric and epidemiological approaches.

  10. Savannah River Site dose control

    International Nuclear Information System (INIS)

    Smith, L.S.

    1992-01-01

    Health physicists from the Brookhaven National Laboratory (BNL) visited the Savannah River Site (SRS) as one of 12 facilities operated by the Department of Energy (DOE) contractors with annual collective dose equivalents greater than 100 person-rem (100 person-cSv). Their charter was to review, evaluate and summarize as low as reasonably achievable (ALARA) techniques, methods and practices as implemented. This presentation gives an overview of the two selected ALARA practices implemented at the SRS: Administrative Exposure Limits and Goal Setting. These dose control methods are used to assure that individual and collective occupational doses are ALARA and within regulatory limits

  11. Mapping of isoexposure curves for evaluation of equivalent environmental doses for radiodiagnostic mobile equipment; Mapeamento de curvas de isoexposicao para avaliacao de equivalente de dose ambiente para equipamentos moveis de radiodiagnostico

    Energy Technology Data Exchange (ETDEWEB)

    Bacelar, Alexandre, E-mail: abacelar@hcpa.ufrgs.b [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Hospital de Clinicas. Setor de Fisica Medica e Radioprotecao; Andrade, Jose Rodrigo Mendes, E-mail: jose.andrade@santacasa.tche.b [Irmandade da Santa Casa de Misericordia de Porto Alegre, RS (Brazil). Servico de Atencao a Saude e Qualidade de Vida; Fischer, Andreia Caroline Fischer da Silveira; Accurso, Andre; Hoff, Gabriela, E-mail: andreia.silveira.001@acad.pucrs.b, E-mail: andre.accurso@acad.pucrs.b [Pontificia Univ. Catolica do Rio Grande do Sul (PUC/RS), Porto Alegre, RS (Brazil). Grupo de Experimentacao e Simulacao Computacional em Fisica Medica

    2011-10-26

    This paper generates iso exposure curves in areas where the mobile radiodiagnostic equipment are used for evaluation of iso kerma map and the environment equivalent dose (H{sup *}(d)). It was used a Shimadzu mobile equipment and two Siemens, with non anthropomorphic scatter. The exposure was measured in a mesh of 4.20 x 4.20 square meter in steps of 30 cm, at half height from the scatterer. The calculation of H{sup *}(d) were estimated for a worker present in all the procedures in a period of 11 months, being considered 3.55 m As/examination and 44.5 procedures/month (adult UTI) and 3.16 m As/examination and 20.1 procedure/month (pediatric UTI), and 3.16 m As/examination and 20.1 procedure/month (pediatric UTI). It was observed that there exist points where the H{sup *}(d) was over the limit established for the free area inside the radius of 30 cm from the central beam of radiation in the case of pediatric UTI and 60 cm for adult UTI. The points localized 2.1 m from the center presented values lower than 25% of those limit

  12. Epidemiological studies on disturbances of human fetal development in areas with various doses of natural background radiation. I. Relationship between incidences of Down's syndrome or visible malformation and gonad dose equivalent rate of natural background radiation

    International Nuclear Information System (INIS)

    Ujeno, Y.

    1985-01-01

    The relationship between environmental radiation to the gonads and incidences of Down's syndrome and visible malformation was analyzed using Kendall's rank correlation method. The subjects, studied during a 3-yr period (1979-1981), were inhabitants of 46 prefectures in Japan that had various dose rates of natural background ionizing radiation. Results showed that the natural background very low-dose radiation rate was not a predominant factor responsible for inducing Down's syndrome or other visible malformations

  13. Medical exposure and effective dose

    International Nuclear Information System (INIS)

    Maruyama, Takashi

    1995-01-01

    The frequency of radiological diagnosis in Japan and individual population effective dose are reported. Questionnaire on radiological practice was delivered to selected medical facilities. The total number of X-ray diagnosis performed in 1991 was 180,000,000, being age-dependent in both men and women. The chest was the most common site to be examined. The number of X-ray films per examination was the highest for the stomach. The spread of ultrasound has decreased radiological practice in the obstetric field (approximately one sixth between 1979 and 1986). There was an 8-fold increase in the number of X-ray CT as of 1989 during the past decade. The total number of CT scanning in 1989 reached nearly 14,850,000 (about 16 times as much as that of 1979). The number of stomach X-ray screening increased to 7,800,000 which is twice as much as that in 1975. In the dental field, panoramic method brought about a 7-fold increase between 1974 and 1985. The frequency of nuclear medicine diagnosis has slightly increased, reaching 1,400,000 cases in 1992, and 99m Tc was the most common nuclide. The total population effective dose of radiography and fluoroscopy was 179,000 mSv. The highest effective dose was associated with gastric X-ray. The effective dose equivalent per diagnosis was estimated to be 1.02 mSv (the total population/total number of radiological diagnosis). The population effective dose per person was 2.3 mSv (population effective dose equivalent/national population), which was equal to the world average of yearly effective dose equivalent of natural radiation. (S.Y.)

  14. Medical exposure and effective dose

    Energy Technology Data Exchange (ETDEWEB)

    Maruyama, Takashi [Association of Radiation Effects, Chiba (Japan)

    1995-09-01

    The frequency of radiological diagnosis in Japan and individual population effective dose are reported. Questionnaire on radiological practice was delivered to selected medical facilities. The total number of X-ray diagnosis performed in 1991 was 180,000,000, being age-dependent in both men and women. The chest was the most common site to be examined. The number of X-ray films per examination was the highest for the stomach. The spread of ultrasound has decreased radiological practice in the obstetric field (approximately one sixth between 1979 and 1986). There was an 8-fold increase in the number of X-ray CT as of 1989 during the past decade. The total number of CT scanning in 1989 reached nearly 14,850,000 (about 16 times as much as that of 1979). The number of stomach X-ray screening increased to 7,800,000 which is twice as much as that in 1975. In the dental field, panoramic method brought about a 7-fold increase between 1974 and 1985. The frequency of nuclear medicine diagnosis has slightly increased, reaching 1,400,000 cases in 1992, and {sup 99m}Tc was the most common nuclide. The total population effective dose of radiography and fluoroscopy was 179,000 mSv. The highest effective dose was associated with gastric X-ray. The effective dose equivalent per diagnosis was estimated to be 1.02 mSv (the total population/total number of radiological diagnosis). The population effective dose per person was 2.3 mSv (population effective dose equivalent/national population), which was equal to the world average of yearly effective dose equivalent of natural radiation. (S.Y.).

  15. Registration of radiation doses

    International Nuclear Information System (INIS)

    2000-02-01

    In Finland the Radiation and Nuclear Safety Authority (STUK) is maintaining the register (called Dose Register) of the radiation exposure of occupationally exposed workers in order to ensure compliance with the principles of optimisation and individual protection. The guide contains a description of the Dose Register and specifies the responsibilities of the party running a radiation practice to report the relevant information to the Dose Register

  16. Doses from portable gauges

    International Nuclear Information System (INIS)

    Linauskas, S.H.

    1988-08-01

    Field studies to measure actual radiation exposures of operators of commercial moisture-density gauges were undertaken in several regions of Canada. Newly developed bubble detector dosimeter technology and conventional dosimetry such as thermoluminescent dosimeters (TLDs), integrating electronic dosimeters (DRDs), and CR-39 neutron track-etch detectors were used to estimate the doses received by 23 moisture-density gauge operators and maintenance staff. These radiation dose estimates were supported by mapping radiation fields and accounting for the time an operator was near a gauge. Major findings indicate that gauge maintenance and servicing workers were more likely than gauge operators to receive exposures above the level of 5 mSv, and that neutron doses were roughly the same as gamma doses. Gauge operators receive approximately 75% of their dose when transporting and carrying the gauge. Dose to their hands is similar to the dose to their trunks, but the dose to their feet area is 6 to 30 times higher. Gamma radiation is the primary source of radiation contributing to operator dose

  17. Paediatric dose display

    International Nuclear Information System (INIS)

    Griffin, D.W.; Derges, S.; Hesslewood, S.

    1984-01-01

    A compact, inexpensive unit, based on an 8085 microprocessor, has been designed for calculating doses of intravenous radioactive injections for children. It has been used successfully for over a year. The dose is calculated from the body surface area and the result displayed in MBq. The operator can obtain the required dose on a twelve character alphanumeric display by entering the age of the patient and the adult dose using a hexadecimal keyboard. Circuit description, memory map and input/output, and firmware are dealt with. (U.K.)

  18. Estimation of equivalent dose and its uncertainty in the OSL SAR protocol when count numbers do not follow a Poisson distribution

    International Nuclear Information System (INIS)

    Bluszcz, Andrzej; Adamiec, Grzegorz; Heer, Aleksandra J.

    2015-01-01

    The current work focuses on the estimation of equivalent dose and its uncertainty using the single aliquot regenerative protocol in optically stimulated luminescence measurements. The authors show that the count numbers recorded with the use of photomultiplier tubes are well described by negative binomial distributions, different ones for background counts and photon induced counts. This fact is then exploited in pseudo-random count number generation and simulations of D e determination assuming a saturating exponential growth. A least squares fitting procedure is applied using different types of weights to determine whether the obtained D e 's and their error estimates are unbiased and accurate. A weighting procedure is suggested that leads to almost unbiased D e estimates. It is also shown that the assumption of Poisson distribution in D e estimation may lead to severe underestimation of the D e error. - Highlights: • Detailed analysis of statistics of count numbers in luminescence readers. • Generation of realistically scattered pseudo-random numbers of counts in luminescence measurements. • A practical guide for stringent analysis of D e values and errors assessment.

  19. Comparing Hp(3) evaluated from the conversion coefficients from air kerma to personal dose equivalent for eye lens dosimetry calibrated on a new cylindrical PMMA phantom

    Science.gov (United States)

    Esor, J.; Sudchai, W.; Monthonwattana, S.; Pungkun, V.; Intang, A.

    2017-06-01

    Based on a new occupational dose limit recommended by ICRP (2011), the annual dose limit for the lens of the eye for workers should be reduced from 150 mSv/y to 20 mSv/y averaged over 5 consecutive years in which no single year exceeding 50 mSv. This new dose limit directly affects radiologists and cardiologists whose work involves high radiation exposure over 20 mSv/y. Eye lens dosimetry (Hp(3)) has become increasingly important and should be evaluated directly based on dosimeters that are worn closely to the eye. Normally, Hp(3) dose algorithm was carried out by the combination of Hp(0.07) and Hp(10) values while dosimeters were calibrated on slab PMMA phantom. Recently, there were three reports from European Union that have shown the conversion coefficients from air kerma to Hp(3). These conversion coefficients carried out by ORAMED, PTB and CEA Saclay projects were performed by using a new cylindrical head phantom. In this study, various delivered doses were calculated using those three conversion coefficients while nanoDot, small OSL dosimeters, were used for Hp(3) measurement. These calibrations were performed with a standard X-ray generator at Secondary Standard Dosimetry Laboratory (SSDL). Delivered doses (Hp(3)) using those three conversion coefficients were compared with Hp(3) from nanoDot measurements. The results showed that percentage differences between delivered doses evaluated from the conversion coefficient of each project and Hp(3) doses evaluated from the nanoDots were found to be not exceeding -11.48 %, -8.85 % and -8.85 % for ORAMED, PTB and CEA Saclay project, respectively.

  20. Occupational dose constraint

    International Nuclear Information System (INIS)

    Heilbron Filho, Paulo Fernando Lavalle; Xavier, Ana Maria

    2005-01-01

    The revision process of the international radiological protection regulations has resulted in the adoption of new concepts, such as practice, intervention, avoidable and restriction of dose (dose constraint). The latter deserving of special mention since it may involve reducing a priori of the dose limits established both for the public and to individuals occupationally exposed, values that can be further reduced, depending on the application of the principle of optimization. This article aims to present, with clarity, from the criteria adopted to define dose constraint values to the public, a methodology to establish the dose constraint values for occupationally exposed individuals, as well as an example of the application of this methodology to the practice of industrial radiography

  1. SU-E-T-365: Estimation of Neutron Ambient Dose Equivalents for Radioprotection Exposed Workers in Radiotherapy Facilities Based On Characterization Patient Risk Estimation

    Energy Technology Data Exchange (ETDEWEB)

    Irazola, L; Terron, J; Sanchez-Doblado, F [Departamento de Fisiologia Medica y Biofisica, Universidad de Sevilla (Spain); Servicio de Radiofisica, Hospital Universitario Virgen Macarena, Sevilla (Spain); Domingo, C; Romero-Exposito, M [Departament de Fisica, Universitat Autonoma de Barcelona, Bellaterra (Spain); Garcia-Fuste, M [Health and Safety Department, ALBA Synchrotron Light Source, Cerdanyola del Valles (Spain); Sanchez-Nieto, B [Instituto de Fisica, Pontificia Universidad Catolica de Chile, Santiago (Chile); Bedogni, R [Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare (INFN) (Italy)

    2015-06-15

    Purpose: Previous measurements with Bonner spheres{sup 1} showed that normalized neutron spectra are equal for the majority of the existing linacs{sup 2}. This information, in addition to thermal neutron fluences obtained in the characterization procedure{sup 3}3, would allow to estimate neutron doses accidentally received by exposed workers, without the need of an extra experimental measurement. Methods: Monte Carlo (MC) simulations demonstrated that the thermal neutron fluence distribution inside the bunker is quite uniform, as a consequence of multiple scatter in the walls{sup 4}. Although inverse square law is approximately valid for the fast component, a more precise calculation could be obtained with a generic fast fluence distribution map around the linac, from MC simulations{sup 4}. Thus, measurements of thermal neutron fluences performed during the characterization procedure{sup 3}, together with a generic unitary spectra{sup 2}, would allow to estimate the total neutron fluences and H*(10) at any point{sup 5}. As an example, we compared estimations with Bonner sphere measurements{sup 1}, for two points in five facilities: 3 Siemens (15–23 MV), Elekta (15 MV) and Varian (15 MV). Results: Thermal neutron fluences obtained from characterization, are within (0.2–1.6×10{sup 6}) cm−{sup 2}•Gy{sup −1} for the five studied facilities. This implies ambient equivalent doses ranging from (0.27–2.01) mSv/Gy 50 cm far from the isocenter and (0.03–0.26) mSv/Gy at detector location with an average deviation of ±12.1% respect to Bonner measurements. Conclusion: The good results obtained demonstrate that neutron fluence and H*(10) can be estimated based on: (a) characterization procedure established for patient risk estimation in each facility, (b) generic unitary neutron spectrum and (c) generic MC map distribution of the fast component. [1] Radiat. Meas (2010) 45: 1391 – 1397; [2] Phys. Med. Biol (2012) 5 7:6167–6191; [3] Med. Phys (2015) 42

  2. Dose response relationship at low doses

    International Nuclear Information System (INIS)

    Schull, W.J.

    1992-01-01

    The data that have accrued in Hiroshima and Nagasaki on the effects of ionizing radiation on the developing human brain are reviewed. Effects considered are severe mental retardation, lowered IQ scores, decline in school performance, seizures, other neuropsychological effects, and small head size. All these factors may be related to radiation doses received by the mother during pregnancy. (L.L.) 3 figs., tab., 7 refs

  3. SU-F-T-02: Estimation of Radiobiological Doses (BED and EQD2) of Single Fraction Electronic Brachytherapy That Equivalent to I-125 Eye Plaque: By Using Linear-Quadratic and Universal Survival Curve Models

    International Nuclear Information System (INIS)

    Kim, Y; Waldron, T; Pennington, E

    2016-01-01

    Purpose: To test the radiobiological impact of hypofractionated choroidal melanoma brachytherapy, we calculated single fraction equivalent doses (SFED) of the tumor that equivalent to 85 Gy of I125-BT for 20 patients. Corresponding organs-at-risks (OARs) doses were estimated. Methods: Twenty patients treated with I125-BT were retrospectively examined. The tumor SFED values were calculated from tumor BED using a conventional linear-quadratic (L-Q) model and an universal survival curve (USC). The opposite retina (α/β = 2.58), macula (2.58), optic disc (1.75), and lens (1.2) were examined. The % doses of OARs over tumor doses were assumed to be the same as for a single fraction delivery. The OAR SFED values were converted into BED and equivalent dose in 2 Gy fraction (EQD2) by using both L-Q and USC models, then compared to I125-BT. Results: The USC-based BED and EQD2 doses of the macula, optic disc, and the lens were on average 118 ± 46% (p < 0.0527), 126 ± 43% (p < 0.0354), and 112 ± 32% (p < 0.0265) higher than those of I125-BT, respectively. The BED and EQD2 doses of the opposite retina were 52 ± 9% lower than I125-BT. The tumor SFED values were 25.2 ± 3.3 Gy and 29.1 ± 2.5 Gy when using USC and LQ models which can be delivered within 1 hour. All BED and EQD2 values using L-Q model were significantly larger when compared to the USC model (p < 0.0274) due to its large single fraction size (> 14 Gy). Conclusion: The estimated single fraction doses were feasible to be delivered within 1 hour using a high dose rate source such as electronic brachytherapy (eBT). However, the estimated OAR doses using eBT were 112 ∼ 118% higher than when using the I125-BT technique. Continued exploration of alternative dose rate or fractionation schedules should be followed.

  4. SU-F-T-02: Estimation of Radiobiological Doses (BED and EQD2) of Single Fraction Electronic Brachytherapy That Equivalent to I-125 Eye Plaque: By Using Linear-Quadratic and Universal Survival Curve Models

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y; Waldron, T; Pennington, E [University Of Iowa, College of Medicine, Iowa City, IA (United States)

    2016-06-15

    Purpose: To test the radiobiological impact of hypofractionated choroidal melanoma brachytherapy, we calculated single fraction equivalent doses (SFED) of the tumor that equivalent to 85 Gy of I125-BT for 20 patients. Corresponding organs-at-risks (OARs) doses were estimated. Methods: Twenty patients treated with I125-BT were retrospectively examined. The tumor SFED values were calculated from tumor BED using a conventional linear-quadratic (L-Q) model and an universal survival curve (USC). The opposite retina (α/β = 2.58), macula (2.58), optic disc (1.75), and lens (1.2) were examined. The % doses of OARs over tumor doses were assumed to be the same as for a single fraction delivery. The OAR SFED values were converted into BED and equivalent dose in 2 Gy fraction (EQD2) by using both L-Q and USC models, then compared to I125-BT. Results: The USC-based BED and EQD2 doses of the macula, optic disc, and the lens were on average 118 ± 46% (p < 0.0527), 126 ± 43% (p < 0.0354), and 112 ± 32% (p < 0.0265) higher than those of I125-BT, respectively. The BED and EQD2 doses of the opposite retina were 52 ± 9% lower than I125-BT. The tumor SFED values were 25.2 ± 3.3 Gy and 29.1 ± 2.5 Gy when using USC and LQ models which can be delivered within 1 hour. All BED and EQD2 values using L-Q model were significantly larger when compared to the USC model (p < 0.0274) due to its large single fraction size (> 14 Gy). Conclusion: The estimated single fraction doses were feasible to be delivered within 1 hour using a high dose rate source such as electronic brachytherapy (eBT). However, the estimated OAR doses using eBT were 112 ∼ 118% higher than when using the I125-BT technique. Continued exploration of alternative dose rate or fractionation schedules should be followed.

  5. Thermoluminescent dosimetry and assessment of personal dose

    International Nuclear Information System (INIS)

    Boas, J.F.; Martin, L.J.; Young, J.G.

    1982-01-01

    Thermoluminescence is discussed in terms of the energy band structure of a crystalline solid and the trapping of charge carriers by point defects. Some general properties of thermoluminescent materials used for dosimetry are outlined, with thermoluminescence of CaSO 4 :Dy being described in detail. The energy response function and the modification of the energy response of a dosimeter by shielding are discussed. The final section covers the connection between exposure, as recorded by a TLD badge, and the absorbed dose to various organs from gamma radiation in a uranium mine; the conversion from absorbed dose to dose equivalent; and uncertainties in assessment of dose equivalent

  6. Estimation of the contribution of neutrons to the equivalent dose for personnel occupationally exposed and public in medical facilities: X-ray with energy equal or greater than 10MV

    International Nuclear Information System (INIS)

    Gonzalez, Alfonso Mayer; Jimenez, Roberto Ortega; Sanchez, Mario A. Reyes; Moranchel y Mejia, Mario

    2013-01-01

    In Mexico the use of electron accelerators for treating cancerous tumors had grown enormously in the last decade. When the treatments are carried out with X-ray beam energy below 10 MV the design of the shielding of the radioactive facility is determined by analyzing the interaction of X-rays, which have a direct impact and dispersion, with materials of the facility. However, when it makes use of X-ray beam energy equal to or greater than 10 MV the neutrons presence is imminent due to their generation by the interaction of the primary beam X-ray with materials head of the accelerator and of the table of treatment, mainly. In these cases, the design and calculation of shielding considers the generation of high-energy neutrons which contribute the equivalent dose that public and Occupationally Staff Exposed (POE) will receive in the areas surrounding the facility radioactive. However, very few measurements have been performed to determine the actual contribution to the neutron dose equivalent received by POE and public during working hours. This paper presents an estimate of the actual contribution of the neutron dose equivalent received by public and POE facilities in various radioactive medical use, considering many factors. To this end, measurements were made of the equivalent dose by using a neutron monitor in areas surrounding different radioactive installations (of Mexico) which used electron accelerators medical use during treatment with X-ray beam energy equal to or greater than 10 MV. The results are presented after a statistical analysis of a wide range of measures in order to estimate more reliability real contribution of the neutron dose equivalent for POE and the public. (author)

  7. Estimation of the contribution by neutrons to the equivalent dose for exposed occupationally personnel and people in medical use facilities: X rays of equal or superior energy to 10 MV

    International Nuclear Information System (INIS)

    Ortega J, R.; Reyes S, M. A.; Moranchel y R, M.

    2013-10-01

    In Mexico the use of electron accelerators for treating cancerous tumors had grown enormously in the last decade. When the treatments are carried out with X-ray beam energy below 10 MV the design of the shielding of the radioactive facility is determined by analyzing the interaction of X-rays, which have a direct impact and dispersion, with materials of the facility. However, when it makes use of X-ray beam energy equal to or greater than 10 MV the neutrons presence is imminent due to their generation by the interaction of the primary beam X-ray with materials head of the accelerator and of the table of treatment, mainly. In these cases, the design and calculation of shielding considers the generation of high-energy neutrons which contribute the equivalent dose that public and occupationally staff exposed (POE) will receive in the areas surrounding the facility radioactive. However, very few measurements have been performed to determine the actual contribution to the neutron dose equivalent received by POE and public during working hours. This paper presents and estimate of the actual contribution of the neutron dose equivalent received by public and POE facilities in various radioactive medical use, considering many factors. To this end, measurements were made of the equivalent dose by using a neutron monitor in areas surrounding different radioactive installations (of Mexico) which used electron accelerators medical use during treatment with X-ray beam energy equal to or greater than 10 MV. The results are presented after a statistical analysis of a wide range of measures in order to estimate more reliability real contribution of the neutron dose equivalent for POE and the public. (author)

  8. Efficacy of Recommended Pre-Hospital Human Equivalent Doses of Atropine and Pralidoxime against the Toxic Effects of Carbamate Poisoning in the Hartley Guinea Pig

    Science.gov (United States)

    Brittain, Matthew K.; McGarry, Kevin G.; Moyer, Robert A.; Babin, Michael C.; Jett, David A.; Platoff, Gennady E.; Yeung, David T.

    2016-01-01

    Purpose Aldicarb and methomyl are carbamate pesticides commonly implicated in human poisonings. The primary toxic mechanism of action for carbamate poisoning is cholinesterase (ChE) inhibition. As such, it is logical to assume that the currently accepted therapies for organophosphate poisoning [muscarinic antagonist atropine and the oxime acetylcholinesterase reactivator pralidoxime chloride (2-PAM Cl),], could afford therapeutic protection. However, oximes have been shown to be contraindicated for poisoning by some carbamates. Methods A protective ratio study was conducted in guinea pigs to evaluate the efficacy of atropine and 2-PAM Cl. ChE activity was determined in both the blood and cerebral cortex.. Results Co-administration of atropine free base (0.4 mg/kg) and 2-PAM Cl (25.7 mg/kg) demonstrated protective ratios of 2 and 3 against aldicarb and methomyl, respectively, relative to saline. The data reported here show that this protection was primarily mediated by the action of atropine. The reactivator 2-PAM Cl had neither positive nor negative effects on survival. Both blood acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities were significantly reduced at 15 minutes post-challenge but gradually returned to normal within 24 h. Analysis of cerebral cortex showed that BChE, but not AChE, activity was reduced in animals that succumbed prior to 24 h after challenge. Conclusion The results suggest that co-administration of atropine and 2-PAM Cl at the currently recommended human equivalent doses for use in the pre-hospital setting to treat organophosphorus nerve agent and pesticide poisoning would likely also be effective against aldicarb or methomyl poisoning. PMID:27102179

  9. Low doses effects

    International Nuclear Information System (INIS)

    Tubiana, M.

    1997-01-01

    In this article is asked the question about a possible carcinogens effect of low dose irradiation. With epidemiological data, knowledge about the carcinogenesis, the professor Tubiana explains that in spite of experiments made on thousand or hundred of thousands animals it has not been possible to bring to the fore a carcinogens effect for low doses and then it is not reasonable to believe and let the population believe that low dose irradiation could lead to an increase of neoplasms and from this point of view any hardening of radiation protection standards could in fact, increase anguish about ionizing radiations. (N.C.)

  10. Doses from radioactive methane

    International Nuclear Information System (INIS)

    Phipps, A.W.; Kendall, G.M.; Fell, T.P.; Harrison, J.D.

    1990-01-01

    A possible radiation hazard arises from exposure to methane labelled with either a 3 H or a 14 C nuclide. This radioactive methane could be released from a variety of sources, e.g. land burial sites containing radioactive waste. Standard assumptions adopted for vapours would not apply to an inert alkane like methane. This paper discusses mechanisms by which radioactive methane would irradiate tissues and provides estimates of doses. Data on skin thickness and metabolism of methane are discussed with reference to these mechanisms. It is found that doses are dominated by dose from the small fraction of methane which is inhaled and metabolised. This component of dose has been calculated under rather conservative assumptions. (author)

  11. Controllable dose; Dosis controlable

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez R, J.T.; Anaya M, R.A. [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico)]. E-mail: jtar@nuclear.inin.mx

    2004-07-01

    With the purpose of eliminating the controversy about the lineal hypothesis without threshold which found the systems of dose limitation of the recommendations of ICRP 26 and 60, at the end of last decade R. Clarke president of the ICRP proposed the concept of Controllable Dose: as the dose or dose sum that an individual receives from a particular source which can be reasonably controllable by means of any means; said concept proposes a change in the philosophy of the radiological protection of its concern by social approaches to an individual focus. In this work a panorama of the foundations is presented, convenient and inconveniences that this proposal has loosened in the international community of the radiological protection, with the purpose of to familiarize to our Mexican community in radiological protection with these new concepts. (Author)

  12. Acetaminophen dosing for children

    Science.gov (United States)

    ... your child, call your provider. Proper Dosing of Suppositories If your child is vomiting or will not take oral medicine, you can use suppositories. Suppositories are placed in the anus to deliver ...

  13. Dose in conventional radiography

    International Nuclear Information System (INIS)

    Acuna D, E.; Padilla R, Z. P.; Escareno J, E.; Vega C, H. R.

    2011-10-01

    It has been pointed out that medical exposures are the most significant sources of exposure to ionizing radiation for the general population. Inside the medical exposures the most important is the X-ray use for diagnosis, which is by far the largest contribution to the average dose received by the population. From all studies performed in radiology the chest radiography is the most abundant. In an X-ray machine, voltage and current are combined to obtain a good image and a reduce dose, however due to the workload in a radiology service individual dose is not monitored. In order to evaluate the dose due to chest radiography in this work a plate phantom was built according to the ISO recommendations using methylmethacrylate walls and water. The phantom was used in the Imaging department of the Zacatecas General Hospital as a radiology patient asking for a chest study; using thermoluminescent dosimeters, TLD 100 the kerma at the surface entrance was determined. (Author)

  14. Ibuprofen dosing for children

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000772.htm Ibuprofen dosing for children To use the sharing features ... much of this medicine can be harmful. How Ibuprofen can Help Your Child Ibuprofen is a type ...

  15. Study of the radiation scattered and produced by concrete shielding of radiotherapy rooms and its effects on equivalent doses in patients' organs; Estudo da radiacao espalhada e produzida pela blindagem de concreto de salas de radioterapia e seus efeitos sobre doses equivalentes nos orgaos dos pacientes

    Energy Technology Data Exchange (ETDEWEB)

    Braga, K.L.; Rebello, W.F.; Andrade, E.R.; Gavazza, S.; Medeiros, M.P.C.; Mendes, R.M.S.; Gomes, R.G.; Silva, M.G., E-mail: kelmo.lins@gmail.com, E-mail: rebello@ime.eb.br, E-mail: fisica.dna@gmail.com, E-mail: sergiogavazza@yahoo.com, E-mail: eng.cavaliere@gmail.com, E-mail: raphaelmsm@gmail.com, E-mail: ggrprojetos@gmail.com, E-mail: maglosilva15@gmail.com [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Engenharia Nuclear; Thalhofer, J.L.; Silva, A.X., E-mail: jardellt@yahoo.com.br, E-mail: ademir@con.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Energia Nuclear; Santos, R.F.G., E-mail: raphaelfgsantos@gmail.com [Centro Universitario Anhanguera, Niteroi, RJ (Brazil). Departamento de Engenharia

    2015-07-01

    Within a radiotherapy room, in addition to the primary beam, there is also secondary radiation due to the leakage of the accelerator head and the radiation scattering from room objects, patient and even the room's shielding itself, which is projected to protect external individuals disregarding its effects on the patient. This work aims to study the effect of concrete shielding wall over the patient, taking into account its contribution on equivalent doses. The MCNPX code was used to model the linear accelerator Varian 2100/2300 C/D operating at 18MeV, with MAX phantom representing the patient undergoing radiotherapy treatment for prostate cancer following Brazilian Institute of Cancer four-fields radiation application protocol (0°, 90°, 180° and 270°). Firstly, the treatment was patterned within a standard radiotherapy room, calculating the equivalent doses on patient's organs individually. In a second step, this treatment was modeled withdrawing the walls, floor and ceiling from the radiotherapy room, and then the equivalent doses calculated again. Comparing these results, it was found that the concrete has an average shielding contribution of around 20% in the equivalent dose on the patient's organs. (author)

  16. Effects of low doses

    International Nuclear Information System (INIS)

    Le Guen, B.

    2001-01-01

    Actually, even though it is comfortable for the risk management, the hypothesis of the dose-effect relationship linearity is not confirmed for any model. In particular, in the area of low dose rate delivered by low let emitters. this hypothesis is debated at the light of recent observations, notably these ones relative to the mechanisms leading to genetic instability and induction eventuality of DNA repair. The problem of strong let emitters is still to solve. (N.C.)

  17. Gonadal doses from radiotherapy

    International Nuclear Information System (INIS)

    Solomon, S.B.; Morris, N.D.

    1980-06-01

    The method of calculation of gonadal doses arising from different radiotherapeutic procedures is described. The measurement of scatter factors to the gonads from superficial and deep therapy is detailed and the analytic fits to the experimental data, as a function of field position, field size and beam energy are given. The data used to calculate the gonadal doses from treatments using linear accelerators, teletherapy and sealed sources are described and the analytic fits to the data given

  18. Determination of the equivalent doses due to the ingestion of radionuclides from the uranium and thorium series presents in drinking waters of the region of Santa Luzia, Paraiba state, Brazil

    International Nuclear Information System (INIS)

    Pastura, Valeria F. da S.; Campos, Thomas F. da C.; Petta, Reinaldo A.

    2011-01-01

    This paper determined the original dose equivalents from radionuclides of uranium and thorium series in a drinking water of well which is supplied to the population of Santa Luzia, Paraiba state, Brazil. The collected waters are near to the mineralized phlegmatic bodies in rose quartz and amazonite feldspar. Radiometric measurements performed on the feldspar vein point out counting ratios surrounding 30000 cps and the analysis of collected samples of minerals presented tenors for the 226 Ra and 219 Pb varying from 0.50 to 2.30 Bq/sw. For determination of concentration of radionuclides U Total , 226 Ra, 228 Ra and 219 Pb, found in the not desalinated, two methods were used, spectrophotometry with arsenazo and radiochemistry, both realized in the CNEN-LAPOC laboratories. For the calculation of dose equivalent it was taken into consideration the following parameters: the dose coefficients for incorporation by ingestion for public individuals with ages over 17 years (Norma CNEN-NN-3.01, Regulatory Position 3.01/011) and daily ingestion of 4 liters of water, which is over the recommended by the WHO of 2L/day - 1993. The obtained values were compared with the reference value for compromised dose equivalent established by WHO for evaluate the risk potential to the health of population, by ingestion. The radionuclide concentrations in the wells varies from 0.054 to 0.21 Bq/L, resulting dose equivalents of 3.94 x 10 -3 mSv/year and 0.17 mSv/year in the studied population

  19. Low-dose dental CT

    International Nuclear Information System (INIS)

    Rustemeyer, P.; Eich, H.T.; John-Mikolajewski, V.; Mueller, R.D.

    1999-01-01

    Purpose: The intention of this study was to reduce patient dose during dental CT in the planning for osseointegrated implants. Methods and Materials: Dental CTs were performed with a spiral CT (Somatom Plus 4, Siemens) and a dental software package. Use of the usual dental CT technique (120 kVp; 165 mA, 1 s rotation time, 165 mAs; pitch factor 1) was compared with a new protocol (120 kVp; 50 mA; 0.7 s rotation time; 35 mAs; pitch factor 2) which delivered the best image quality at the lowest possible radiation dose, as tested in a preceding study. Image quality was analysed using a human anatomic head preparation. Four radiologists analysed the images independently. A Wilcoxon rank pair-test was used for statistic evaluation. The doses to the thyroid gland, the active bone marrow, the salivary glands, and the eye lens were determined in a tissue-equivalent phantom (Alderson-Rando Phantom) with lithium fluoride thermoluminescent dosimeters at the appropriate locations. Results: By mAs reduction from 165 to 35 and using a pitch factor of 2, the radiation dose could be reduced by a factor of nine (max.) (e.g., the bone marrow dose could be reduced from 23.6 mSv to 2.9 mSv, eye lens from 0.5 mSv to 0.3 mSv, thyroid gland from 2.5 mSv to 0.5 mSv, parotid glands from 2.3 mSv to 0.4 mSv). The dose reduction did not lead to an actual loss of image quality or diagnostic information. Conclusion: A considerable dose reduction without loss of diagnostic information is achievable in dental CT. Dosereducing examination protocols like the one presented may further expand the use of preoperative dental CT. (orig.) [de

  20. SU-F-J-193: Efficient Dose Extinction Method for Water Equivalent Path Length (WEPL) of Real Tissue Samples for Validation of CT HU to Stopping Power Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, R; Baer, E; Jee, K; Sharp, G; Flanz, J; Lu, H [Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States)

    2016-06-15

    Purpose: For proton therapy, an accurate model of CT HU to relative stopping power (RSP) conversion is essential. In current practice, validation of these models relies solely on measurements of tissue substitutes with standard compositions. Validation based on real tissue samples would be much more direct and can address variations between patients. This study intends to develop an efficient and accurate system based on the concept of dose extinction to measure WEPL and retrieve RSP in biological tissue in large number of types. Methods: A broad AP proton beam delivering a spread out Bragg peak (SOBP) is used to irradiate the samples with a Matrixx detector positioned immediately below. A water tank was placed on top of the samples, with the water level controllable in sub-millimeter by a remotely controlled dosing pump. While gradually lowering the water level with beam on, the transmission dose was recorded at 1 frame/sec. The WEPL were determined as the difference between the known beam range of the delivered SOBP (80%) and the water level corresponding to 80% of measured dose profiles in time. A Gammex 467 phantom was used to test the system and various types of biological tissue was measured. Results: RSP for all Gammex inserts, expect the one made with lung-450 material (<2% error), were determined within ±0.5% error. Depends on the WEPL of investigated phantom, a measurement takes around 10 min, which can be accelerated by a faster pump. Conclusion: Based on the concept of dose extinction, a system was explored to measure WEPL efficiently and accurately for a large number of samples. This allows the validation of CT HU to stopping power conversions based on large number of samples and real tissues. It also allows the assessment of beam uncertainties due to variations over patients, which issue has never been sufficiently studied before.

  1. SU-F-J-193: Efficient Dose Extinction Method for Water Equivalent Path Length (WEPL) of Real Tissue Samples for Validation of CT HU to Stopping Power Conversion

    International Nuclear Information System (INIS)

    Zhang, R; Baer, E; Jee, K; Sharp, G; Flanz, J; Lu, H

    2016-01-01

    Purpose: For proton therapy, an accurate model of CT HU to relative stopping power (RSP) conversion is essential. In current practice, validation of these models relies solely on measurements of tissue substitutes with standard compositions. Validation based on real tissue samples would be much more direct and can address variations between patients. This study intends to develop an efficient and accurate system based on the concept of dose extinction to measure WEPL and retrieve RSP in biological tissue in large number of types. Methods: A broad AP proton beam delivering a spread out Bragg peak (SOBP) is used to irradiate the samples with a Matrixx detector positioned immediately below. A water tank was placed on top of the samples, with the water level controllable in sub-millimeter by a remotely controlled dosing pump. While gradually lowering the water level with beam on, the transmission dose was recorded at 1 frame/sec. The WEPL were determined as the difference between the known beam range of the delivered SOBP (80%) and the water level corresponding to 80% of measured dose profiles in time. A Gammex 467 phantom was used to test the system and various types of biological tissue was measured. Results: RSP for all Gammex inserts, expect the one made with lung-450 material (<2% error), were determined within ±0.5% error. Depends on the WEPL of investigated phantom, a measurement takes around 10 min, which can be accelerated by a faster pump. Conclusion: Based on the concept of dose extinction, a system was explored to measure WEPL efficiently and accurately for a large number of samples. This allows the validation of CT HU to stopping power conversions based on large number of samples and real tissues. It also allows the assessment of beam uncertainties due to variations over patients, which issue has never been sufficiently studied before.

  2. Validation of GPU based TomoTherapy dose calculation engine.

    Science.gov (United States)

    Chen, Quan; Lu, Weiguo; Chen, Yu; Chen, Mingli; Henderson, Douglas; Sterpin, Edmond

    2012-04-01

    The graphic processing unit (GPU) based TomoTherapy convolution/superposition(C/S) dose engine (GPU dose engine) achieves a dramatic performance improvement over the traditional CPU-cluster based TomoTherapy dose engine (CPU dose engine). Besides the architecture difference between the GPU and CPU, there are several algorithm changes from the CPU dose engine to the GPU dose engine. These changes made the GPU dose slightly different from the CPU-cluster dose. In order for the commercial release of the GPU dose engine, its accuracy has to be validated. Thirty eight TomoTherapy phantom plans and 19 patient plans were calculated with both dose engines to evaluate the equivalency between the two dose engines. Gamma indices (Γ) were used for the equivalency evaluation. The GPU dose was further verified with the absolute point dose measurement with ion chamber and film measurements for phantom plans. Monte Carlo calculation was used as a reference for both dose engines in the accuracy evaluation in heterogeneous phantom and actual patients. The GPU dose engine showed excellent agreement with the current CPU dose engine. The majority of cases had over 99.99% of voxels with Γ(1%, 1 mm) GPU dose engine also showed similar degree of accuracy in heterogeneous media as the current TomoTherapy dose engine. It is verified and validated that the ultrafast TomoTherapy GPU dose engine can safely replace the existing TomoTherapy cluster based dose engine without degradation in dose accuracy.

  3. Is it beneficial to selectively boost high-risk tumor subvolumes? A comparison of selectively boosting high-risk tumor subvolumes versus homogeneous dose escalation of the entire tumor based on equivalent EUD plans

    International Nuclear Information System (INIS)

    Kim, Yusung; To me, Wolfgang A.

    2008-01-01

    Purpose. To quantify and compare expected local tumor control and expected normal tissue toxicities between selective boosting IMRT and homogeneous dose escalation IMRT for the case of prostate cancer. Methods. Four different selective boosting scenarios and three different high-risk tumor subvolume geometries were designed to compare selective boosting and homogeneous dose escalation IMRT plans delivering the same equivalent uniform dose (EUD) to the entire PTV. For each scenario, differences in tumor control probability between both boosting strategies were calculated for the high-risk tumor subvolume and remaining low-risk PTV, and were visualized using voxel based iso-TCP maps. Differences in expected rectal and bladder complications were quantified using radiobiological indices (generalized EUD (gEUD) and normal tissue complication probability (NTCP)) as well as %-volumes. Results. For all investigated scenarios and high-risk tumor subvolume geometries, selective boosting IMRT improves expected TCP compared to homogeneous dose escalation IMRT, especially when lack of control of the high-risk tumor subvolume could be the cause for tumor recurrence. Employing, selective boosting IMRT significant increases in expected TCP can be achieved for the high-risk tumor subvolumes. The three conventional selective boosting IMRT strategies, employing physical dose objectives, did not show significant improvement in rectal and bladder sparing as compared to their counterpart homogeneous dose escalation plans. However, risk-adaptive optimization, utilizing radiobiological objective functions, resulted in reduction in NTCP for the rectum when compared to its corresponding homogeneous dose escalation plan. Conclusions. Selective boosting is a more effective method than homogeneous dose escalation for achieving optimal treatment outcomes. Furthermore, risk-adaptive optimization increases the therapeutic ratio as compared to conventional selective boosting IMRT

  4. Assessment of internal doses

    CERN Document Server

    Rahola, T; Falk, R; Isaksson, M; Skuterud, L

    2002-01-01

    There is a definite need for training in dose calculation. Our first course was successful and was followed by a second, both courses were fully booked. An example of new tools for software products for bioassay analysis and internal dose assessment is the Integrated Modules for Bioassay Analysis (IMBA) were demonstrated at the second course. This suite of quality assured code modules have been adopted in the UK as the standard for regulatory assessment purposes. The intercomparison measurements are an important part of the Quality Assurance work. In what is known as the sup O utside workers ' directive it is stated that the internal dose measurements shall be included in the European Unions supervision system for radiation protection. The emergency preparedness regarding internal contamination was much improved by the training with and calibration of handheld instruments from participants' laboratories. More improvement will be gained with the handbook giving practical instructions on what to do in case of e...

  5. Dose evaluation from multiple detector outputs using convex optimisation

    International Nuclear Information System (INIS)

    Hashimoto, M.; Iimoto, T.; Kosako, T.

    2011-01-01

    A dose evaluation using multiple radiation detectors can be improved by the convex optimisation method. It enables flexible dose evaluation corresponding to the actual radiation energy spectrum. An application to the neutron ambient dose equivalent evaluation is investigated using a mixed-gas proportional counter. The convex derives the certain neutron ambient dose with certain width corresponding to the true neutron energy spectrum. The range of the evaluated dose is comparable to the error of conventional neutron dose measurement equipments. An application to the neutron individual dose equivalent measurement is also investigated. Convexes of particular dosemeter combinations evaluate the individual dose equivalent better than the dose evaluation of a single dosemeter. The combinations of dosemeters with high orthogonality of their response characteristics tend to provide a good suitability for dose evaluation. (authors)

  6. Determination of the equivalent doses due to the ingestion of radionuclides from the uranium and thorium series presents in drinking waters of the region of Santa Luzia, Paraiba state, Brazil; Determinacao das doses equivalentes devido a ingestao de radionuclideos das series do uranio e torio presentes em aguas de consumo do municipio de Santa Luzia, estado da Paraiba

    Energy Technology Data Exchange (ETDEWEB)

    Pastura, Valeria F. da S., E-mail: vpastura@cnen.gov.b [Comissao Nacional de Energia Nuclear (DRSN/CNEN), Rio de Janeiro, RJ (Brazil). Diretoria de Radioprotecao e Seguranca Nuclear. Coordenacao de Materias Primas e Minerais; Campos, Thomas F. da C.; Petta, Reinaldo A., E-mail: thomascampos@geologia.ufrn.b, E-mail: petta@geologia.ufrn.b [Universidade Federal do Rio Grande do Norte (LARANA/UFRN), Natal, RN (Brazil). Lab. de Radioatividade Natural

    2011-10-26

    This paper determined the original dose equivalents from radionuclides of uranium and thorium series in a drinking water of well which is supplied to the population of Santa Luzia, Paraiba state, Brazil. The collected waters are near to the mineralized phlegmatic bodies in rose quartz and amazonite feldspar. Radiometric measurements performed on the feldspar vein point out counting ratios surrounding 30000 cps and the analysis of collected samples of minerals presented tenors for the {sup 226}Ra and {sup 219}Pb varying from 0.50 to 2.30 Bq/sw. For determination of concentration of radionuclides U{sub Total}, {sup 226}Ra, {sup 228}Ra and {sup 219}Pb, found in the not desalinated, two methods were used, spectrophotometry with arsenazo and radiochemistry, both realized in the CNEN-LAPOC laboratories. For the calculation of dose equivalent it was taken into consideration the following parameters: the dose coefficients for incorporation by ingestion for public individuals with ages over 17 years (Norma CNEN-NN-3.01, Regulatory Position 3.01/011) and daily ingestion of 4 liters of water, which is over the recommended by the WHO of 2L/day - 1993. The obtained values were compared with the reference value for compromised dose equivalent established by WHO for evaluate the risk potential to the health of population, by ingestion. The radionuclide concentrations in the wells varies from 0.054 to 0.21 Bq/L, resulting dose equivalents of 3.94 x 10{sup -3} mSv/year and 0.17 mSv/year in the studied population

  7. Dose Reduction Techniques

    International Nuclear Information System (INIS)

    WAGGONER, L.O.

    2000-01-01

    As radiation safety specialists, one of the things we are required to do is evaluate tools, equipment, materials and work practices and decide whether the use of these products or work practices will reduce radiation dose or risk to the environment. There is a tendency for many workers that work with radioactive material to accomplish radiological work the same way they have always done it rather than look for new technology or change their work practices. New technology is being developed all the time that can make radiological work easier and result in less radiation dose to the worker or reduce the possibility that contamination will be spread to the environment. As we discuss the various tools and techniques that reduce radiation dose, keep in mind that the radiological controls should be reasonable. We can not always get the dose to zero, so we must try to accomplish the work efficiently and cost-effectively. There are times we may have to accept there is only so much you can do. The goal is to do the smart things that protect the worker but do not hinder him while the task is being accomplished. In addition, we should not demand that large amounts of money be spent for equipment that has marginal value in order to save a few millirem. We have broken the handout into sections that should simplify the presentation. Time, distance, shielding, and source reduction are methods used to reduce dose and are covered in Part I on work execution. We then look at operational considerations, radiological design parameters, and discuss the characteristics of personnel who deal with ALARA. This handout should give you an overview of what it takes to have an effective dose reduction program

  8. Dose Reduction Techniques

    Energy Technology Data Exchange (ETDEWEB)

    WAGGONER, L.O.

    2000-05-16

    As radiation safety specialists, one of the things we are required to do is evaluate tools, equipment, materials and work practices and decide whether the use of these products or work practices will reduce radiation dose or risk to the environment. There is a tendency for many workers that work with radioactive material to accomplish radiological work the same way they have always done it rather than look for new technology or change their work practices. New technology is being developed all the time that can make radiological work easier and result in less radiation dose to the worker or reduce the possibility that contamination will be spread to the environment. As we discuss the various tools and techniques that reduce radiation dose, keep in mind that the radiological controls should be reasonable. We can not always get the dose to zero, so we must try to accomplish the work efficiently and cost-effectively. There are times we may have to accept there is only so much you can do. The goal is to do the smart things that protect the worker but do not hinder him while the task is being accomplished. In addition, we should not demand that large amounts of money be spent for equipment that has marginal value in order to save a few millirem. We have broken the handout into sections that should simplify the presentation. Time, distance, shielding, and source reduction are methods used to reduce dose and are covered in Part I on work execution. We then look at operational considerations, radiological design parameters, and discuss the characteristics of personnel who deal with ALARA. This handout should give you an overview of what it takes to have an effective dose reduction program.

  9. 10 CFR 20.1004 - Units of radiation dose.

    Science.gov (United States)

    2010-01-01

    ... beta radiation 1 1 Alpha particles, multiple-charged particles, fission fragments and heavy particles... convenient to measure the neutron fluence rate than to determine the neutron dose equivalent rate in rems per... measured tissue dose in rads to dose equivalent in rems. Table 1004(b).2—Mean Quality Factors, Q, and...

  10. Multiple anatomy optimization of accumulated dose

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, W. Tyler, E-mail: watkinswt@virginia.edu; Siebers, Jeffrey V. [Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia 22908 and Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States); Moore, Joseph A. [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland 21231 and Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States); Gordon, James [Henry Ford Health System, Detroit, Michigan 48202 and Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States); Hugo, Geoffrey D. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States)

    2014-11-01

    Purpose: To investigate the potential advantages of multiple anatomy optimization (MAO) for lung cancer radiation therapy compared to the internal target volume (ITV) approach. Methods: MAO aims to optimize a single fluence to be delivered under free-breathing conditions such that the accumulated dose meets the plan objectives, where accumulated dose is defined as the sum of deformably mapped doses computed on each phase of a single four dimensional computed tomography (4DCT) dataset. Phantom and patient simulation studies were carried out to investigate potential advantages of MAO compared to ITV planning. Through simulated delivery of the ITV- and MAO-plans, target dose variations were also investigated. Results: By optimizing the accumulated dose, MAO shows the potential to ensure dose to the moving target meets plan objectives while simultaneously reducing dose to organs at risk (OARs) compared with ITV planning. While consistently superior to the ITV approach, MAO resulted in equivalent OAR dosimetry at planning objective dose levels to within 2% volume in 14/30 plans and to within 3% volume in 19/30 plans for each lung V20, esophagus V25, and heart V30. Despite large variations in per-fraction respiratory phase weights in simulated deliveries at high dose rates (e.g., treating 4/10 phases during single fraction beams) the cumulative clinical target volume (CTV) dose after 30 fractions and per-fraction dose were constant independent of planning technique. In one case considered, however, per-phase CTV dose varied from 74% to 117% of prescription implying the level of ITV-dose heterogeneity may not be appropriate with conventional, free-breathing delivery. Conclusions: MAO incorporates 4DCT information in an optimized dose distribution and can achieve a superior plan in terms of accumulated dose to the moving target and OAR sparing compared to ITV-plans. An appropriate level of dose heterogeneity in MAO plans must be further investigated.

  11. Multiple anatomy optimization of accumulated dose.

    Science.gov (United States)

    Watkins, W Tyler; Moore, Joseph A; Gordon, James; Hugo, Geoffrey D; Siebers, Jeffrey V

    2014-11-01

    To investigate the potential advantages of multiple anatomy optimization (MAO) for lung cancer radiation therapy compared to the internal target volume (ITV) approach. MAO aims to optimize a single fluence to be delivered under free-breathing conditions such that the accumulated dose meets the plan objectives, where accumulated dose is defined as the sum of deformably mapped doses computed on each phase of a single four dimensional computed tomography (4DCT) dataset. Phantom and patient simulation studies were carried out to investigate potential advantages of MAO compared to ITV planning. Through simulated delivery of the ITV- and MAO-plans, target dose variations were also investigated. By optimizing the accumulated dose, MAO shows the potential to ensure dose to the moving target meets plan objectives while simultaneously reducing dose to organs at risk (OARs) compared with ITV planning. While consistently superior to the ITV approach, MAO resulted in equivalent OAR dosimetry at planning objective dose levels to within 2% volume in 14/30 plans and to within 3% volume in 19/30 plans for each lung V20, esophagus V25, and heart V30. Despite large variations in per-fraction respiratory phase weights in simulated deliveries at high dose rates (e.g., treating 4/10 phases during single fraction beams) the cumulative clinical target volume (CTV) dose after 30 fractions and per-fraction dose were constant independent of planning technique. In one case considered, however, per-phase CTV dose varied from 74% to 117% of prescription implying the level of ITV-dose heterogeneity may not be appropriate with conventional, free-breathing delivery. MAO incorporates 4DCT information in an optimized dose distribution and can achieve a superior plan in terms of accumulated dose to the moving target and OAR sparing compared to ITV-plans. An appropriate level of dose heterogeneity in MAO plans must be further investigated.

  12. Multiple anatomy optimization of accumulated dose

    International Nuclear Information System (INIS)

    Watkins, W. Tyler; Siebers, Jeffrey V.; Moore, Joseph A.; Gordon, James; Hugo, Geoffrey D.

    2014-01-01

    Purpose: To investigate the potential advantages of multiple anatomy optimization (MAO) for lung cancer radiation therapy compared to the internal target volume (ITV) approach. Methods: MAO aims to optimize a single fluence to be delivered under free-breathing conditions such that the accumulated dose meets the plan objectives, where accumulated dose is defined as the sum of deformably mapped doses computed on each phase of a single four dimensional computed tomography (4DCT) dataset. Phantom and patient simulation studies were carried out to investigate potential advantages of MAO compared to ITV planning. Through simulated delivery of the ITV- and MAO-plans, target dose variations were also investigated. Results: By optimizing the accumulated dose, MAO shows the potential to ensure dose to the moving target meets plan objectives while simultaneously reducing dose to organs at risk (OARs) compared with ITV planning. While consistently superior to the ITV approach, MAO resulted in equivalent OAR dosimetry at planning objective dose levels to within 2% volume in 14/30 plans and to within 3% volume in 19/30 plans for each lung V20, esophagus V25, and heart V30. Despite large variations in per-fraction respiratory phase weights in simulated deliveries at high dose rates (e.g., treating 4/10 phases during single fraction beams) the cumulative clinical target volume (CTV) dose after 30 fractions and per-fraction dose were constant independent of planning technique. In one case considered, however, per-phase CTV dose varied from 74% to 117% of prescription implying the level of ITV-dose heterogeneity may not be appropriate with conventional, free-breathing delivery. Conclusions: MAO incorporates 4DCT information in an optimized dose distribution and can achieve a superior plan in terms of accumulated dose to the moving target and OAR sparing compared to ITV-plans. An appropriate level of dose heterogeneity in MAO plans must be further investigated

  13. Radioactive cloud dose calculations

    International Nuclear Information System (INIS)

    Healy, J.W.

    1984-01-01

    Radiological dosage principles, as well as methods for calculating external and internal dose rates, following dispersion and deposition of radioactive materials in the atmosphere are described. Emphasis has been placed on analytical solutions that are appropriate for hand calculations. In addition, the methods for calculating dose rates from ingestion are discussed. A brief description of several computer programs are included for information on radionuclides. There has been no attempt to be comprehensive, and only a sampling of programs has been selected to illustrate the variety available

  14. Dose model for inhalation

    International Nuclear Information System (INIS)

    Raicevic, J.; Ninkovic, M.; Merkle, M.

    1997-01-01

    This paper deals with calculation of doses in the environment. There are in general five exposure pathways which are customarily considered within such calculations: cloud shine, ground shine, inhalation after resuspension and ingestion. Since in fact each of these exposure pathways is represented by an independent mechanism, it is usual to consider these environmental dose models separately for each exposure pathway. As one example, the inhalation of the material from the radioactive passing cloud, as well as the inhalation of the radioactive material resuspended in the air are considered, giving the same formulas which are used in the new european accident consequence assessment code system COSYMA. (author)

  15. Determination of the conversion coefficient for ambient dose equivalent, H(10), from air kerma measurements; Determinacion del coeficiente de conversion para la dosis equivalente ambiental, H*(10), a partir de mediciones de kerma en aire

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez J, F. [UNAM, Facultad de Ciencias, Circuito Exterior, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Alvarez R, J. T., E-mail: trinidad.alvarez@inin.gob.mx [ININ, Departamento de Metrologia de Radiaciones Ionizantes, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2015-09-15

    Namely the operational magnitudes can be determined by the product of a conversion coefficient by exposure air kerma or fluence, etc. In particular in Mexico for the first time is determined the conversion coefficient (Cc) for operational magnitude Environmental Dose Equivalent H(10) by thermoluminescence dosimetry (TLD) technique. First 30 TLD-100 dosimeters are calibrated in terms of air kerma, then these dosimeters are irradiated inside a sphere ICRU type of PMMA and with the aid of theory cavity the absorbed dose in PMMA is determined at a depth of 10 mm within the sphere D{sub PMMA}(10), subsequently absorbed dose to ICRU tissue is corrected and the dose equivalent H(10) is determined. The Cc is determined as the ratio of H(10)/K{sub a} obtaining a value of 1.20 Sv Gy{sup -1} with a u{sub c}= 3.66%, this being consistent with the published value in ISO-4037-3 of 1.20 Sv Gy{sup -1} with a u{sub c}= 2%. (Author)

  16. Antiproton radiotherapy: peripheral dose from secondary neutrons

    DEFF Research Database (Denmark)

    Fahimian, Benjamin P.; DeMarco, John J.; Keyes, Roy

    2009-01-01

    is the normal tissue dose resulting from secondary neutrons produced in the annihilation of antiprotons on the nucleons of the target atoms. Here we present the first organ specific Monte Carlo calculations of normal tissue equivalent neutron dose in antiproton therapy through the use of a segmented CT......-based human phantom. The MCNPX Monte Carlo code was employed to quantify the peripheral dose for a cylindrical spread out Bragg peak representing a treatment volume of 1 cm diameter and 1 cm length in the frontal lobe of a segmented whole-body phantom of a 38 year old male. The secondary neutron organ dose...

  17. Dose Reduction Techniques

    CERN Document Server

    Waggoner, L O

    2000-01-01

    As radiation safety specialists, one of the things we are required to do is evaluate tools, equipment, materials and work practices and decide whether the use of these products or work practices will reduce radiation dose or risk to the environment. There is a tendency for many workers that work with radioactive material to accomplish radiological work the same way they have always done it rather than look for new technology or change their work practices. New technology is being developed all the time that can make radiological work easier and result in less radiation dose to the worker or reduce the possibility that contamination will be spread to the environment. As we discuss the various tools and techniques that reduce radiation dose, keep in mind that the radiological controls should be reasonable. We can not always get the dose to zero, so we must try to accomplish the work efficiently and cost-effectively. There are times we may have to accept there is only so much you can do. The goal is to do the sm...

  18. When is a dose not a dose?

    International Nuclear Information System (INIS)

    Bond, V.P.

    1991-01-01

    Although an enormous amount of progress has been made in the fields of radiation protection and risk assessment, a number of significant problems remain. The one problem which transcends all the rest, and which has been subject to considerable misunderstanding, involves what has come to be known as the 'linear non-threshold hypothesis', or 'linear hypothesis'. Particularly troublesome has been the interpretation that any amount of radiation can cause an increase in the excess incidence of cancer. The linear hypothesis has dominated radiation protection philosophy for more than three decades, with enormous financial, societal and political impacts and has engendered an almost morbid fear of low-level exposure to ionizing radiation in large segments of the population. This document presents a different interpretation of the linear hypothesis. The basis for this view lies in the evolution of dose-response functions, particularly with respect to their use initially in the context of early acute effects, and then for the late effects, carcinogenesis and mutagenesis. 11 refs., 4 figs

  19. Dose tracking and dose auditing in a comprehensive computed tomography dose-reduction program.

    Science.gov (United States)

    Duong, Phuong-Anh; Little, Brent P

    2014-08-01

    Implementation of a comprehensive computed tomography (CT) radiation dose-reduction program is a complex undertaking, requiring an assessment of baseline doses, an understanding of dose-saving techniques, and an ongoing appraisal of results. We describe the role of dose tracking in planning and executing a dose-reduction program and discuss the use of the American College of Radiology CT Dose Index Registry at our institution. We review the basics of dose-related CT scan parameters, the components of the dose report, and the dose-reduction techniques, showing how an understanding of each technique is important in effective auditing of "outlier" doses identified by dose tracking. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. In search of the relevant lung dose

    International Nuclear Information System (INIS)

    Fisher, D.R.

    1982-12-01

    Researchers have traditionally been inconsistent in their methods of determining and reporting dose to the lung from inhaled radionuclides - a situation which has led to difficulties in later comparing results and deriving dose-response relationships. The dose quantities which at present are most generally assumed to be related to risk of stochastic radiation effects (such as lung cancer) are (1) mean dose equivalent to the bronchial epithelium basal cell layer for radon daughters, and (2) mean dose equivalent to the whole lung (including tracheobronchial lymph nodes) for all other radionuclides. The average radiation dose is calculated by assuming that the energy is homogeneously impared to the entire tissue mass. However, the actual dose received by a cell which becomes transformed or tumorigenic is likely to be very much different than the smear dose to the entire organ. This realization has led to further study of stochastic energy deposition processes in single cells or cell nuclei from internal emitters. The end product of the stochastic approach to dosimetry, sometimes called microdosimetry, is a probability density in specific energy. For alpha-emitting radionuclides in the lung, a concept that may be more important than dose is the probability that a cell is hit by an alpha particle

  1. Tumor significant dose

    International Nuclear Information System (INIS)

    Supe, S.J.; Nagalaxmi, K.V.; Meenakshi, L.

    1983-01-01

    In the practice of radiotherapy, various concepts like NSD, CRE, TDF, and BIR are being used to evaluate the biological effectiveness of the treatment schedules on the normal tissues. This has been accepted as the tolerance of the normal tissue is the limiting factor in the treatment of cancers. At present when various schedules are tried, attention is therefore paid to the biological damage of the normal tissues only and it is expected that the damage to the cancerous tissues would be extensive enough to control the cancer. Attempt is made in the present work to evaluate the concent of tumor significant dose (TSD) which will represent the damage to the cancerous tissue. Strandquist in the analysis of a large number of cases of squamous cell carcinoma found that for the 5 fraction/week treatment, the total dose required to bring about the same damage for the cancerous tissue is proportional to T/sup -0.22/, where T is the overall time over which the dose is delivered. Using this finding the TSD was defined as DxN/sup -p/xT/sup -q/, where D is the total dose, N the number of fractions, T the overall time p and q are the exponents to be suitably chosen. The values of p and q are adjusted such that p+q< or =0.24, and p varies from 0.0 to 0.24 and q varies from 0.0 to 0.22. Cases of cancer of cervix uteri treated between 1978 and 1980 in the V. N. Cancer Centre, Kuppuswamy Naidu Memorial Hospital, Coimbatore, India were analyzed on the basis of these formulations. These data, coupled with the clinical experience, were used for choice of a formula for the TSD. Further, the dose schedules used in the British Institute of Radiology fraction- ation studies were also used to propose that the tumor significant dose is represented by DxN/sup -0.18/xT/sup -0.06/

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

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

    Science.gov (United States)

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

    2010-09-01

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

  4. Entrance surface dose according to dose calculation: Head and wrist

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Ho Jin [Dept. Radiology, Chonnam National University Hospital, Gwangju (Korea, Republic of); Han, Jae Bok; Song, Jong Nam; Choi, Nam Gil [Dept. of Radiological Science, Dongshin University, Naju (Korea, Republic of)

    2016-09-15

    This study were compared with the direct measurement and indirect dose methods through various dose calculation in head and wrist. And, the modified equation was proposed considering equipment type, setting conditions, tube voltage, inherent filter, added filter and its accompanied back scatter factor. As a result, it decreased the error of the direct measurement than the existing dose calculation. Accordingly, diagnostic radiography patient dose comparison would become easier and radiographic exposure control and evaluation will become more efficient. The study findings are expected to be useful in patients' effective dose rate evaluation and dose reduction.

  5. Incorporation of eicosapentaenoic and docosahexaenoic acids into lipid pools when given as supplements providing doses equivalent to typical intakes of oily fish.

    Science.gov (United States)

    Browning, Lucy M; Walker, Celia G; Mander, Adrian P; West, Annette L; Madden, Jackie; Gambell, Joanna M; Young, Stephen; Wang, Laura; Jebb, Susan A; Calder, Philip C

    2012-10-01

    Estimation of the intake of oily fish at a population level is difficult. The measurement of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in biological samples may provide a useful biomarker of intake. We identified the most appropriate biomarkers for the assessment of habitual oily fish intake and changes in intake by elucidating the dose- and time-dependent response of EPA and DHA incorporation into various biological samples that represent roles in fatty acid transport, function, and storage. This was a double-blind, randomized, controlled intervention trial in 204 men and women that lasted 12 mo. EPA and DHA capsules were provided in a manner to reflect sporadic consumption of oily fish (ie, 1, 2, or 4 times/wk). EPA and DHA were assessed at 9 time points over 12 mo in 9 sample types (red blood cells, mononuclear cells, platelets, buccal cells, adipose tissue, plasma phosphatidylcholine, triglycerides, cholesteryl esters, and nonesterified fatty acids). A dose response (P 12 mo (adipose tissue). Plasma phosphatidylcholine EPA plus DHA was identified as the most suitable biomarker of acute changes in EPA and DHA intake, and platelet and mononuclear cell EPA plus DHA were the most suitable biomarkers of habitual intake.

  6. Small dose... big poison.

    Science.gov (United States)

    Braitberg, George; Oakley, Ed

    2010-11-01

    It is not possible to identify all toxic substances in a single journal article. However, there are some exposures that in small doses are potentially fatal. Many of these exposures are particularly toxic to children. Using data from poison control centres, it is possible to recognise this group of exposures. This article provides information to assist the general practitioner to identify potential toxic substance exposures in children. In this article the authors report the signs and symptoms of toxic exposures and identify the time of onset. Where clear recommendations on the period of observation and known fatal dose are available, these are provided. We do not discuss management or disposition, and advise readers to contact the Poison Information Service or a toxicologist for this advice.

  7. First dose in man

    DEFF Research Database (Denmark)

    Hougaard Christensen, Mette Marie

    2011-01-01

    Du er blevet ansat som læge i et lægemiddelfirma med ansvar for planlægning og sikkerhed i fase 1 forsøg. Firmaet har udviklet tre dopamin D2-receptor antagonister til behandling af skizofreni. Lægemidlerne har undergået et omfattende farmakologisk, toksikologisk og farmaceutisk afprøvningsprogra...... fase 1 forsøg alias »First dose in man«....

  8. Evaluation of Dose Distribution and a Pilot Study of Population Doses for Diagnostic X Ray Exposure in Taiwan in 1997

    International Nuclear Information System (INIS)

    Yeh, H.; Hsu, J.; Yin, L.; Su, F.

    1999-01-01

    Evaluating medical radiation doses is very important because an estimated 80% of man-made radiation doses comes from medical applications. This study evaluated X ray doses from lung and abdomen examinations. An ionisation chamber was extensively used to standardise X ray doses. This investigation evaluated the deep equivalent dose, the shallow equivalent dose, the effective dose, and the effective dose equivalent, by using TLD LiF:Mg,Ti placed in a male RANDO phantom. The experiments were performed according to the parameters (kV p , mA.s) and procedures used in actual clinical examinations. In addition, this study estimated the population dose due to diagnostic X ray treatments using nationwide statistics for annual cases of X ray diagnostic examinations, in cooperation with the Central Health Insurance Agency in Taiwan. Finally, risk analyses were performed to elucidate the stochastic effects. (author)

  9. Development of a computational model for the calculation of neutron dose equivalent in laminated primary barriers of radiotherapy rooms; Desenvolvimento de um modelo computacional para calculo do equivalente de dose de neutrons em barreiras primarias laminadas de salas de radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Rezende, Gabriel Fonseca da Silva

    2015-06-01

    Many radiotherapy centers acquire 15 and 18 MV linear accelerators to perform more effective treatments for deep tumors. However, the acquisition of these equipment must be accompanied by an additional care in shielding planning of the rooms that will house them. In cases where space is restricted, it is common to find primary barriers made of concrete and metal. The drawback of this type of barrier is the photoneutron emission when high energy photons (e.g. 15 and 18 MV spectra) interact with the metallic material of the barrier. The emission of these particles constitutes a problem of radiation protection inside and outside of radiotherapy rooms, which should be properly assessed. A recent work has shown that the current model underestimate the dose of neutrons outside the treatment rooms. In this work, a computational model for the aforementioned problem was created from Monte Carlo Simulations and Artificial Intelligence. The developed model was composed by three neural networks, each being formed of a pair of material and spectrum: Pb18, Pb15 and Fe18. In a direct comparison with the McGinley method, the Pb18 network exhibited the best responses for approximately 78% of the cases tested; the Pb15 network showed better results for 100% of the tested cases, while the Fe18 network produced better answers to 94% of the tested cases. Thus, the computational model composed by the three networks has shown more consistent results than McGinley method. (author)

  10. Dose calculation for electrons

    International Nuclear Information System (INIS)

    Hirayama, Hideo

    1995-01-01

    The joint working group of ICRP/ICRU is advancing the works of reviewing the ICRP publication 51 by investigating the data related to radiation protection. In order to introduce the 1990 recommendation, it has been demanded to carry out calculation for neutrons, photons and electrons. As for electrons, EURADOS WG4 (Numerical Dosimetry) rearranged the data to be calculated at the meeting held in PTB Braunschweig in June, 1992, and the question and request were presented by Dr. J.L. Chartier, the responsible person, to the researchers who are likely to undertake electron transport Monte Carlo calculation. The author also has carried out the requested calculation as it was the good chance to do the mutual comparison among various computation codes regarding electron transport calculation. The content that the WG requested to calculate was the absorbed dose at depth d mm when parallel electron beam enters at angle α into flat plate phantoms of PMMA, water and ICRU4-element tissue, which were placed in vacuum. The calculation was carried out by the versatile electron-photon shower computation Monte Carlo code, EGS4. As the results, depth dose curves and the dependence of absorbed dose on electron energy, incident angle and material are reported. The subjects to be investigated are pointed out. (K.I.)

  11. Dose reduction in evacuation proctography

    International Nuclear Information System (INIS)

    Hare, C.; Halligan, S.; Bartram, C.I.; Gupta, R.; Walker, A.E.; Renfrew, I.

    2001-01-01

    The goal of this study was to reduce the patient radiation dose from evacuation proctography. Ninety-eight consecutive adult patients referred for proctography to investigate difficult rectal evacuation were studied using a digital imaging system with either a standard digital program for barium examinations, a reduced dose digital program (both with and without additional copper filtration), or Video fluoroscopy. Dose-area products were recorded for each examination and the groups were compared. All four protocols produced technically acceptable examinations. The low-dose program with copper filtration (median dose 382 cGy cm 2 ) and Video fluoroscopy (median dose 705 cGy cm 2 ) were associated with significantly less dose than other groups (p < 0.0001). Patient dose during evacuation proctography can be reduced significantly without compromising the diagnostic quality of the examination. A digital program with added copper filtration conveyed the lowest dose. (orig.)

  12. Measurements of U and Ra Activities in Drinking Water Samples and of Rn in Dwellings in Morocco. Calculation of Equivalent Effective Doses

    International Nuclear Information System (INIS)

    Choukri, A.; Hakam, O.K.

    2013-01-01

    Activities of uranium and radium isotopes were measured in some drinking water samples collected from wells, springs and tap water samples. The obtained results show that the 238 U activity, is relatively higher in wells than in springs and 226 Ra activity is more higher in hot springs. The results are similar to those published for other non polluting regions of the world and don't present any risk for public health in Morocco. In parallel measurements of indoor radon showed that the calculated effective dose for dwellings are comparable to those obtained in other regions in the word. The risks related to these activities could be avoided by simple precautions such the continuous ventilation.

  13. Evaluation of the radiation doses to uranium mine employees exposed to external gamma radiation

    International Nuclear Information System (INIS)

    Young, J.G.; Wilson, O.J.

    1983-02-01

    Factors to convert a personal monitor badge reading to an effective dose equivalent are given for several exposure geometries encountered in uranium mines. Factors are also given that relate a free air absorbed dose measurement to an effective dose equivalent. In addition, factors are reported which can be used to estimate the dose equivalent to the testes, ovaries and active bone marrow

  14. Transit dose calculation in high dose rate brachytherapy (HDR ...

    African Journals Online (AJOL)

    Transit doses around a high dose rate 192Ir brachytherapy source were calculated using Sievert Integral at positions where the moving source was located exactly between two adjacent dwell positions. The correspond-ing transit dose rates were obtained by using energy absorption coefficients. Discrete step sizes of 0.25 ...

  15. Conversion of dose volume constraints to dose limits

    Energy Technology Data Exchange (ETDEWEB)

    Dai Jianrong [Department of Radiological Science, St Jude Children' s Research Hospital, Memphis, TN 38105 (United States); Zhu Yunping [Department of Radiological Science, St Jude Children' s Research Hospital, Memphis, TN 38105 (United States)

    2003-12-07

    The purpose of this study is to introduce two techniques for converting dosevolume constraints to dose limits for treatment planning optimization, and to evaluate their performance. The first technique, called dose-sorting, is based on the assumption that higher dose limits should be assigned to the constraint points receiving higher doses, and vice versa. The second technique, the hybrid technique, is a hybrid of the dose-sorting technique and the mixed integer linear programming (MILP) technique. Among all constraint points in an organ at risk, the dose limits for the points far from a dosevolume constraint are determined by dose-sorting, while the dose limits for the points close to a dosevolume constraint are determined by MILP. We evaluated the performance of the two new techniques for one treatment geometry by comparing them with the MILP technique. The dose-sorting technique had a high probability of finding the global optimum when no more than three organs at risk have dose-volume constraints. It was much faster than the MILP technique. The hybrid technique always found the global optimum when the MILP percentage (the percentage of constraint points for which the dose limits are determined by the MILP technique) was large enough, but its computation time increased dramatically with the MILP percentage. In conclusion, the dose-sorting technique and the hybrid technique with a low MILP percentage are clinically feasible.

  16. Didactic revision of the operative magnitudes system ICRU for the evaluation of the equivalent dose in radiation external fields; Revision didactica del sistema de magnitudes operativas ICRU para la evaluacion de la dosis equivalente en campos externos de radiacion

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez R, J. T., E-mail: trinidad.alvarez@inin.gob.mx [ININ, Departamento de Metrologia de Radiaciones Ionizantes, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2014-10-15

    In this work is presented in a didactic way the operative magnitudes system ICRU, showing as these magnitudes carry out an appropriate estimate of the effective equivalent doses H{sub E} and the effective dose. The objective is to present the basic concepts of the dosimetry for radiation external fields with purposes of radiological protection, because the assimilation lack and technological development of this dosimetric magnitudes system has persisted for near 50 years, in terms of practice of the radiological protection in Mexico. Also, this system is an essential part of safety basic standards of the IAEA and ICRP recommendations 26, 60, 74 and 103, as well as of the ICRU 25, 39, 43, 51 and 57. (Author)

  17. Dose-to-man studies

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Dose-to-Man Studies focused on developing computer data handling and computer modules which permit easy, rapid assessment of the dose to southeastern United States populations from routine or accidental releases of radionuclides to atmospheric and stream systems

  18. Dose. Detriment. Limit assessment

    International Nuclear Information System (INIS)

    Breckow, J.

    2015-01-01

    One goal of radiation protection is the limitation of stochastic effects due to radiation exposure. The probability of occurrence of a radiation induced stochastic effect, however, is only one of several other parameters which determine the radiation detriment. Though the ICRP-concept of detriment is a quantitative definition, the kind of detriment weighting includes somewhat subjective elements. In this sense, the detriment-concept of ICRP represents already at the stage of effective dose a kind of assessment. Thus, by comparing radiation protection standards and concepts interconvertible or with those of environment or occupational protection one should be aware of the possibly different principles of detriment assessment.

  19. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Finch, S.M.; McMakin, A.H. (comps.)

    1991-01-01

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): Source terms; environmental transport environmental monitoring data; demographics, agriculture, food habits; environmental pathways and dose estimates.

  20. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Finch, S.M.; McMakin, A.H. (comps.)

    1992-02-01

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): source terms; environmental transport; environmental monitoring data; demography, food consumption, and agriculture; environmental pathways and dose estimates.

  1. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, S.D.; Finch, S.M. (comps.)

    1992-10-01

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The independent Technical Steering Panel (TSP) provides technical direction. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impact on humans (dose estimates):Source Terms, Environmental Transport, Environmental Monitoring Data, Demography, Food Consumption, and Agriculture, and Environmental Pathways and Dose Estimates.

  2. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Finch, S.M.; McMakin, A.H. (comps.)

    1992-01-01

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): Source Terms, Environmental Transport, Environmental Monitoring Data, Demography, Food Consumption, and Agriculture, and Environmental Pathways and Dose Estimates.

  3. Hanford Environmental Dose Reconstruction Project

    International Nuclear Information System (INIS)

    Cannon, S.D.; Finch, S.M.

    1992-10-01

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The independent Technical Steering Panel (TSP) provides technical direction. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impact on humans (dose estimates):Source Terms, Environmental Transport, Environmental Monitoring Data, Demography, Food Consumption, and Agriculture, and Environmental Pathways and Dose Estimates

  4. Dose reduction at nuclear power plants

    International Nuclear Information System (INIS)

    Baum, J.W.; Dionne, B.J.

    1983-01-01

    The collective dose equivalent at nuclear power plants increased from 1250 rem in 1969 to nearly 54,000 rem in 1980. This rise is attributable primarily to an increase in nuclear generated power from 1289 MW-y to 29,155 MW-y; and secondly, to increased average plant age. However, considerable variation in exposure occurs from plant to plant depending on plant type, refueling, maintenance, etc. In order to understand the factors influencing these differences, an investigation was initiated to study dose-reduction techniques and effectiveness of as low as reasonably achievable (ALARA) planning at light water plants. Objectives are to: identify high-dose maintenance tasks and related dose-reduction techniques; investigate utilization of high-reliability, low-maintenance equipment; recommend improved radioactive waste handling equipment and procedures; examine incentives for dose reduction; and compile an ALARA handbook

  5. Radiation doses from radioactivity in incandescent mantles

    International Nuclear Information System (INIS)

    1985-01-01

    Thorium nitrate is used in the production of incandescent mantles for gas lanterns. In this report dose estimates are given for internal and external exposure that result from the use of the incandescent mantles for gas lanterns. The collective, effective dose equivalent for all users of gas mantles is estimated to be about 100 Sv per annum in the Netherlands. For the population involved (ca. 700,000 persons) this is roughly equivalent to 5% to 10% of the collective dose equivalent associated with exposure to radiation from natural sources. The major contribution to dose estimates comes from inhalation of radium during burning of the mantles. A pessimistic approach results in individual dose estimates for inhalation of up to 0.2 mSv. Consideration of dose consequences in case of a fire in a storage department learns that it is necessary for emergency personnel to wear respirators. It is concluded that the uncontrolled removal of used gas mantles to the environment (soil) does not result in a significant contribution to environmental radiation exposure. (Auth.)

  6. Dose planning and dose delivery in radiation therapy

    International Nuclear Information System (INIS)

    Knoeoes, T.

    1991-01-01

    A method has been developed for calibration of CT-numbers to volumetric electron density distributions using tissue substitutes of known elemental composition and experimentally determined electron density. This information have been used in a dose calculation method based on photon and electron interaction processes. The method utilizes a convolution integral between the photon fluence matrix and dose distribution kernels. Inhomogeneous media are accounted for using the theorems of Fano and O'Connor for scaling dose distribution kernels in proportion to electron density. For clinical application of a calculated dose plan, a method for prediction of accelerator output have been developed. The methods gives the number of monitor units that has to be given to obtain a certain absorbed dose to a point inside an irregular, inhomogeneous object. The method for verification of dose distributions outlined in this study makes it possible to exclude the treatment related variance contributions, making an objective evaluation of dose calculations with experiments feasible. The methods for electron density determination, dose calculation and prediction of accelerator output discussed in this study will all contribute to an increased accuracy in the mean absorbed dose to the target volume. However, a substantial gain in the accuracy for the spatial absorbed dose distribution will also follow, especially using CT for mapping of electron density together with the dose calculation algorithm. (au)

  7. Bio-equivalent doses of recombinant HCG and recombinant LH during ovarian stimulation result in similar oestradiol output: a randomized controlled study.

    Science.gov (United States)

    Alsbjerg, Birgit; Elbaek, Helle Olesen; Laursen, Rita Jakubcionyte; Povlsen, Betina Boel; Haahr, Thor; Yding Andersen, Claus; Humaidan, Peter

    2017-08-01

    In nature, HCG is secreted by the implanting embryo from peri-implantation and onwards. In contrast, LH is mandatory for steroidogenesis and follicular development during the follicular phase, working in synergy with FSH. Moreover, LH is mandatory for the function of the corpus luteum. Although LH and HCG bind to the same receptor, significant molecular, structural and functional differences exist, inducing differences in bioactivity. This randomized controlled study compared the effect of recombinant FSH stimulation combined with daily either micro-dose recombinant HCG or recombinant LH supplementation in a 1:1 bioactivity ratio from day 1 of stimulation in a long gonadotrophin releasing hormone agonist down regulation protocol. A total of 100 patients from a public clinic completed the study. The primary end-point was the oestradiol level on the day of ovulation trigger and the median oestradiol level in the HCG supplemented group was 8662 pmol/l versus 9203 pmol/l in the recombinant LH supplemented group; therefore, no significant difference was found. Moreover, no differences were observed in the number of oocytes retrieved or in the live birth rate. We conclude that recombinant HCG and recombinant LH are equally effective in boosting oestradiol synthesis during ovarian stimulation when used in a 1:1 bioactivity ratio. Copyright © 2017 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  8. Internal dose conversion factors for calculation of dose to the public

    International Nuclear Information System (INIS)

    1988-07-01

    This publication contains 50-year committed dose equivalent factors, in tabular form. The document is intended to be used as the primary reference by the US Department of Energy (DOE) and its contractors for calculating radiation dose equivalents for members of the public, resulting from ingestion or inhalation of radioactive materials. Its application is intended specifically for such materials released to the environment during routine DOE operations, except in those instances where compliance with 40 CFR 61 (National Emission Standards for Hazardous Air Pollutants) requires otherwise. However, the calculated values may be equally applicable to unusual releases or to occupational exposures. The use of these committed dose equivalent tables should ensure that doses to members of the public from internal exposures are calculated in a consistent manner at all DOE facilities

  9. Peripheral dose from megavolt beams

    International Nuclear Information System (INIS)

    Fraass, B.A.; van de Geijn, J.

    1983-01-01

    The peripheral dose (PD), defined as the dose outside of therapeutic radiation beams, has been investigated for 60 Co, 4-, 6-, and 10-MV x-ray machines. The measurements have been carried out down to dose levels of about 0.1% of the peak dose in the beam, since that dose level may be of clinical importance in some situations. The PD measurements for the various machines are qualitatively similar, which allows the identification of a simple basic data set which can characterize the PD for any particular machine. The PD has been separated into two components: in-phantom scatter dose and transmission (leakage) dose. Knowledge of the two components is important clinically when shielding is considered

  10. Surface dose in intracavitary orthovoltage radiotherapy

    International Nuclear Information System (INIS)

    Podgorsak, M.B.; Schreiner, L.J.; Podgorsak, E.B.

    1990-01-01

    Radiotherapy with orthovoltage techniques is often the prime treatment for localized superficial malignancies. Surface doses and depth doses measured with cylindrical and end-window Farmer chambers are presented for various orthovoltage x-ray beams in the range from 80 to 300 kVp, both for open beams and beams collimated with commercial intracavitary leaded-glass cones. For radiation fields collimated by a diaphragm positioned at a distance from the patient surface (open beams) there is a small skin-sparing effect. On the other hand, the surface doses with commercial leaded-glass intracavitary cones can exhibit a fivefold increase compared to the open-beam dose maxima. Beyond a depth of ∼0.2 mm in a tissue-equivalent phantom, the doses measured for open beams and beams collimated with intracavitary cones are essentially identical. The increase in the surface dose observed with intracavitary cones is attributed to photoelectrons and recoil electrons produced in the cones. The high surface doses are measured by thin-wall parallel-plate ionization chambers but cannot be measured with cylindrical Farmer chambers since these chambers have wall thicknesses too large for the transmission of electrons produced in the cone. Since cylindrical Farmer chambers are typically used for calibration of radiation output, the high surface doses produced by the intracavitary cones may be overlooked; they can, however, be reduced to open-beam values by simple modifications to the cones

  11. A phase I, randomized, single-dose study evaluating the pharmacokinetic equivalence of biosimilar ABP 215 and bevacizumab in healthy adult men.

    Science.gov (United States)

    Markus, Richard; Chow, Vincent; Pan, Zhiying; Hanes, Vladimir

    2017-10-01

    This study compared the pharmacokinetic (PK) profiles of the proposed biosimilar ABP 215 with bevacizumab in healthy males. In this randomized, single-blind, single-dose, three-arm, parallel-group study, healthy subjects were randomized to receive ABP 215 (n = 68), bevacizumab (US) (n = 67), or bevacizumab (EU) (n = 67) 3 mg/kg intravenously. Primary endpoints were area under the serum concentration-time curve from time 0 extrapolated to infinity (AUC inf ) and the maximum observed concentration (C max ). Secondary endpoints included safety and immunogenicity. AUC inf and C max were similar across the three groups. Geometric means ratio (GMR) for C max and AUC inf , respectively, was 0.98 and 0.99 for ABP 215 versus bevacizumab (US); 1.03 and 0.96 for ABP 215 versus bevacizumab (EU); and 1.05 and 0.97 for bevacizumab (US) versus bevacizumab (EU). The 90% confidence intervals for the GMRs of AUC inf and C max were within the prespecified standard PK bioequivalence criteria of 0.80 to 1.25. The incidence of adverse events (AEs) was 47.1, 32.8, and 61.2% in the ABP 215, bevacizumab (US) and bevacizumab (EU) groups, respectively. When analyzed by investigational site, the incidence and severity of AEs were comparable in the ABP 215 and bevacizumab groups. There were no AEs leading to study discontinuation. No binding or neutralizing anti-drug anti-bodies was detected. This study demonstrated the PK similarity of ABP 215 to both bevacizumab (US) and bevacizumab (EU), and of bevacizumab (US) to bevacizumab (EU). Safety and tolerability were comparable between treatments and no subject developed binding or neutralizing anti-drug anti-bodies.

  12. A study of neutron doses in water and sea water

    International Nuclear Information System (INIS)

    Abou-Taleb, W.M.; Abou El-Khier, A.A.; Fawzy Salem, M.A.; Gaber, M.; El-Khatib, A.M.

    1988-01-01

    Experimental measurements have been carried out to determine the neutron flux from a compact D-T neutron generator in tissue equivalent mediums like water and sea water, and NaCl. The measurements were performed by using neutron activation foils as neutron detectors of successive threshold energies. The flux-dose conversion factors, as well as related quality factors averaged over the selected energy ranges, were used to determine equivalent dose and adsorbed dose rates, respectively. The experimental and calculated results were found to be in a good agreement. Besides, dose buildup factors were determined. The contribution of thermal and intermediate neutron dose is relatively lower than that for fast neutrons. (author)

  13. Brachytherapy dose measurements in heterogeneous tissues

    Energy Technology Data Exchange (ETDEWEB)

    Paiva F, G.; Luvizotto, J.; Salles C, T.; Guimaraes A, P. C.; Dalledone S, P. de T.; Yoriyaz, H. [Instituto de Pesquisas Energeticas e Nucleares / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil); Rubo, R., E-mail: gabrielpaivafonseca@gmail.com [Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, 05403-900 Sao Paulo (Brazil)

    2014-08-15

    Recently, Beau lieu et al. published an article providing guidance for Model-Based Dose Calculation Algorithms (MBDCAs), where tissue heterogeneity considerations are addressed. It is well-known that T G-43 formalism which considers only water medium is limited and significant dose differences have been found comparing both methodologies. The aim of the present work is to experimentally quantify dose values in heterogeneous medium using different dose measurement methods and techniques and compare them with those obtained with Monte Carlo simulations. Experiments have been performed using a Nucletron micro Selectron-Hdr Ir-192 brachytherapy source and a heterogeneous phantom composed by PMMA and different tissue equivalent cylinders like bone, lungs and muscle. Several dose measurements were obtained using tissue equivalent materials with height 1.8 cm and 4.3 cm positioned between the radiation source and the detectors. Radiochromic films, TLDs and MOSFET S have been used for the dose measurements. Film dosimetry has been performed using two methodologies: a) linearization for dose-response curve based on calibration curves to create a functional form that linearize s the dose response and b) 177 multichannel analysis dosimetry where the multiple color channels are analyzed allowing to address not only disturbances in the measurements caused by thickness variation in the film layer, but also, separate other external influences in the film response. All experiments have been simulated using the MCNP5 Monte Carlo radiation transport code. Comparison of experimental results are in good agreement with calculated dose values with differences less than 6% for almost all cases. (Author)

  14. Conventional radiology and genetic dose

    International Nuclear Information System (INIS)

    Gonzalez-Vila, V.; Fernandez, A.; Rivera, F.; Martinez, M.; Gomez, A.; Luis, J.

    1992-01-01

    A research project was established in 1984 to evaluate the expected genetic abnormalities due to radiation received by the population attending the Outpatient Radiological Service due to medical radiological practices. The study was conducted in 1985 (12 weeks chosen by random). The equivalent gonadal dose was the chosen parameter, representing the social cost of the radiology. Samples of 2945 men and 2929 women were considered in the study. The number of genetic abnormalities, in relation to the mean age of reproduction (a generation every 30 years), was 2.13 cases per million in the first generation and 15.97 cases per million at equilibrium. The authors interpretation is that both the method and the expected genetic detriment are suitable procedures for the characterisation of the Radiological Service as a radiation source. (author)

  15. Doses in mammography. Preliminary study

    International Nuclear Information System (INIS)

    Marquez P, F.; Acosta R, N.; Universidad Nacional Mayor de San Marcos, Lima; Benavente, T.; Universidad Nacional Mayor de San Marcos, Lima; Poma, M.

    2002-01-01

    Mammography is the most important method to detect lesions in the breast with this technique one can detect small tumours before clear clinical symptoms appear. Mammographic image of require high quality standards due that the extremely low contrast between the normal and pathological areas in the breast, eg.g., they have similar attenuation and absorption coefficient. The x-ray mammographic systems, used in this study are Senographe 500t and Senographe DMR, a detector with a RadCal ionization chambers calibrated to the qualities of mammographic x-ray beams, and a breast simulator that is a phantoms of polymethylmethacrylate (PMMA) of several thicknesses with the equivalence of 50% of the glandular tissue. The results obtained indicate that the values of doses at the entrance surface of a breast (DES) are greater the reference value 20 mGy to 5,0 cm of PMMA and the values of the mean glandular dose (MGD) exceed the reference value of 2,1 mGy for 5,1 cm of compressed thick breast. We consider that the values high of the EDS and MGD are due that the x-ray systems no meeting in good condition or for used of x-ray spectra no suitable, so is recommendable be carried out test of quality control to the x-ray systems and also realize studies, or characterize the of x-ray mammographic spectra

  16. Comparison of conversion coefficients for equivalent dose in terms of air kerma using a sitting and standing female adult voxel simulators exposure to photons in antero-posterior irradiation geometry

    Science.gov (United States)

    Cavalcante, F. R.; Galeano, D. C.; Carvalho Júnior, A. B.; Hunt, J.

    2014-02-01

    Due to the difficulty in implementing invasive techniques for calculations of dose for some exposure scenarios, computational simulators have been created to represent as realistically as possible the structures of the human body and through radiation transport simulations to obtain conversion coefficients (CCs) to estimate dose. In most published papers simulators are implemented in the standing posture and this may not describe a real scenario of exposure. In this work we developed exposure scenarios in the Visual Monte Carlo (VMC) code using a female simulator in standing and sitting postures. The simulator was irradiated in the antero-posterior (AP) geometry by a plane source of monoenergetic photons with energy from 10 keV to 2 MeV. The conversion coefficients for equivalent dose in terms of air kerma (HT/Kair) were calculated for both scenarios and compared. The results show that the percentage difference of CCs for the organs of the head and thorax was not significant (less than 5%) since the anatomic position of the organs is the same in both postures. The percentage difference is more significant to the ovaries (71% for photon energy of 20 keV), to the bladder (39% at 60 keV) and to the uterus (37% at 100 keV) due to different processes of radiation interactions in the legs of the simulator when its posture is changed. For organs and tissues that are distributed throughout the entire body, such as bone (21% at 100 keV) and muscle (30% at 80 keV) the percentage difference of CCs reflects a reduction of interaction of photons with the legs of the simulator. Therefore, the calculation of conversion coefficients using simulators in the sitting posture is relevant for a more accurate dose estimation in real exposures to radiation.

  17. INTERCOMPARISON ON THE MEASUREMENT OF THE QUANTITY PERSONAL DOSE EQUIVALENT HP(10) IN PHOTON FIELDS. LINEARITY DEPENDENCE, LOWER LIMIT OF DETECTION AND UNCERTAINTY IN MEASUREMENT OF DOSIMETRY SYSTEMS OF INDIVIDUAL MONITORING SERVICES IN GABON AND GHANA.

    Science.gov (United States)

    Ondo Meye, P; Schandorf, C; Amoako, J K; Manteaw, P O; Amoatey, E A; Adjei, D N

    2017-12-01

    An inter-comparison study was conducted to assess the capability of dosimetry systems of individual monitoring services (IMSs) in Gabon and Ghana to measure personal dose equivalent Hp(10) in photon fields. The performance indicators assessed were the lower limit of detection, linearity and uncertainty in measurement. Monthly and quarterly recording levels were proposed with corresponding values of 0.08 and 0.025 mSv, and 0.05 and 0.15 mSv for the TLD and OSL systems, respectively. The linearity dependence of the dosimetry systems was performed following the requirement given in the Standard IEC 62387 of the International Electrotechnical Commission (IEC). The results obtained for the two systems were satisfactory. The procedure followed for the uncertainty assessment is the one given in the IEC technical report TR62461. The maximum relative overall uncertainties, in absolute value, expressed in terms of Hp(10), for the TL dosimetry system Harshaw 6600, are 44. 35% for true doses below 0.40 mSv and 36.33% for true doses ≥0.40 mSv. For the OSL dosimetry system microStar, the maximum relative overall uncertainties, in absolute value, are 52.17% for true doses below 0.40 mSv and 37.43% for true doses ≥0.40 mSv. These results are in good agreement with the requirements for accuracy of the International Commission on Radiological protection. When expressing the uncertainties in terms of response, comparison with the IAEA requirements for overall accuracy showed that the uncertainty results were also acceptable. The values of Hp(10) directly measured by the two dosimetry systems showed a significant underestimation for the Harshaw 6600 system, and a slight overestimation for the microStar system. After correction for linearity of the measured doses, the two dosimetry systems gave better and comparable results. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Fundamental investigations of natural and laboratory generated SAR dose response curves for quartz OSL in the high dose range

    DEFF Research Database (Denmark)

    Timar-Gabor, Alida; Constantin, Daniela; Buylaert, Jan-Pieter

    2015-01-01

    SAR-OSL investigations on quartz from Romanian loess resulted in non concordant fine and coarse-grain ages for equivalent doses higher than ~100 Gy. The laboratory dose response for both grain sizes is well represented by a sum of two saturating exponential functions, fine and coarse grains chara...... equivalent dose of 2000e2500 Gy were found to be below the saturation level of the laboratory dose response curve for both grain sizes; this also applied to the luminescence signals measured after >5000 Gy given on top of natural doses. © 2015 Elsevier Ltd. All rights reserved....

  19. Methotrexate Dosing Regimen for Plaque-type Psoriasis : A Systematic Review of the Use of Test-dose, Start-dose, Dosing Scheme, Dose Adjustments, Maximum Dose and Folic Acid Supplementation

    NARCIS (Netherlands)

    Menting, Stef P; Dekker, Paul M; Limpens, Jacqueline; Hooft, Lotty; Spuls, Phyllis I

    2016-01-01

    There is a range of methotrexate dosing regimens for psoriasis. This review summarizes the evidence for test-dose, start-dose, dosing scheme, dose adjustments, maximum dose and use of folic acid. A literature search for randomized controlled trials and guidelines was performed. Twenty-three

  20. Methotrexate Dosing Regimen for Plaque-type Psoriasis: A Systematic Review of the Use of Test-dose, Start-dose, Dosing Scheme, Dose Adjustments, Maximum Dose and Folic Acid Supplementation

    NARCIS (Netherlands)

    Menting, Stef P.; Dekker, Paul M.; Limpens, Jacqueline; Hooft, Lotty; Spuls, Phyllis I.

    2016-01-01

    There is a range of methotrexate dosing regimens for psoriasis. This review summarizes the evidence for test-dose, start-dose, dosing scheme, dose adjustments, maximum dose and use of folic acid. A literature search for randomized controlled trials and guidelines was performed. Twenty-three

  1. Occupational dose reduction developments and data collected at nuclear power plants

    International Nuclear Information System (INIS)

    Dionne, B.J.; Baum, J.W.

    1984-01-01

    Occupational dose reduction developments and data collected at nuclear power plants have been described. Written descriptions of repetitive high dose jobs, their collective dose equivalent ranges and list of dose reduction techniques will aid in reducing collective dose equivalents from these dose-reduction targets. Knowing which components contribute to high maintenance or repair dose will aid in reducing routine maintenance collective dose equivalents. The radwaste dose reduction improvements will aid in reducing radwaste operations collective dose equivalent and reduce the number of radwaste workers who exceed their administrative dose limits. The identification and rating of managers' and workers' ALARA incentives will provide the basis for recommendations to improve dose reduction incentives. Lastly, the identification and rating of the key components of an ALARA program will aid in the development and coordination of the nuclear station ALARA programs

  2. In defence of collective dose

    International Nuclear Information System (INIS)

    Fairlie, I.; Sumner, D.

    2000-01-01

    Recent proposals for a new scheme of radiation protection leave little room for collective dose estimations. This article discusses the history and present use of collective doses for occupational, ALARA, EIS and other purposes with reference to practical industry papers and government reports. The linear no-threshold (LNT) hypothesis suggests that collective doses which consist of very small doses added together should be used. Moral and ethical questions are discussed, particularly the emphasis on individual doses to the exclusion of societal risks, uncertainty over effects into the distant future and hesitation over calculating collective detriments. It is concluded that for moral, practical and legal reasons, collective dose is a valid parameter which should continue to be used. (author)

  3. Does Vertebroplasty Affect Radiation Dose Distribution?: Comparison of Spatial Dose Distributions in a Cement-Injected Vertebra as Calculated by Treatment Planning System and Actual Spatial Dose Distribution

    International Nuclear Information System (INIS)

    Komemushi, A.; Tanigawa, N.; Kariya, Sh.; Yagi, R.; Nakatani, M.; Suzuki, S.; Sano, A.; Ikeda, K.; Utsunomiya, K.; Harima, Y.; Sawada, S.

    2012-01-01

    Purpose. To assess differences in dose distribution of a vertebral body injected with bone cement as calculated by radiation treatment planning system (RTPS) and actual dose distribution. Methods. We prepared two water-equivalent phantoms with cement, and the other two phantoms without cement. The bulk density of the bone cement was imported into RTPS to reduce error from high CT values. A dose distribution map for the phantoms with and without cement was calculated using RTPS with clinical setting and with the bulk density importing. Actual dose distribution was measured by the film density. Dose distribution as calculated by RTPS was compared to the dose distribution measured by the film dosimetry. Results. For the phantom with cement, dose distribution was distorted for the areas corresponding to inside the cement and on the ventral side of the cement. However, dose distribution based on film dosimetry was undistorted behind the cement and dose increases were seen inside cement and around the cement. With the equivalent phantom with bone cement, differences were seen between dose distribution calculated by RTPS and that measured by the film dosimetry. Conclusion. The dose distribution of an area containing bone cement calculated using RTPS differs from actual dose distribution

  4. Fast in vivo volume dose reconstruction via reference dose perturbation

    International Nuclear Information System (INIS)

    Lu, Weiguo; Chen, Mingli; Mo, Xiaohu; Parnell, Donald; Olivera, Gustavo; Galmarini, Daniel

    2014-01-01

    Purpose: Accurate on-line reconstruction of in-vivo volume dose that accounts for both machine and patient discrepancy is not clinically available. We present a simple reference-dose-perturbation algorithm that reconstructs in-vivo volume dose fast and accurately. Methods: We modelled the volume dose as a function of the fluence map and density image. Machine (output variation, jaw/leaf position errors, etc.) and patient (setup error, weight loss, etc.) discrepancies between the plan and delivery were modelled as perturbation of the fluence map and density image, respectively. Delivered dose is modelled as perturbation of the reference dose due to change of the fluence map and density image. We used both simulated and clinical data to validate the algorithm. The planned dose was used as the reference. The reconstruction was perturbed from the reference and accounted for output-variations and the registered daily image. The reconstruction was compared with the ground truth via isodose lines and the Gamma Index. Results: For various plans and geometries, the volume doses were reconstructed in few seconds. The reconstruction generally matched well with the ground truth. For the 3%/3mm criteria, the Gamma pass rates were 98% for simulations and 95% for clinical data. The differences mainly appeared on the surface of the phantom/patient. Conclusions: A novel reference-dose-perturbation dose reconstruction model is presented. The model accounts for machine and patient discrepancy from planning. The algorithm is simple, fast, yet accurate, which makes online in-vivo 3D dose reconstruction clinically feasible.

  5. Calibration of photographic dosemeters to evaluate the personal equivalent dose, Hp (10), irradiated by different radiation qualities and angles of incidence; Calibracao de dosimetros fotograficos para avaliar o equivalente de dose pessoal, Hp(10), irradiados por diferentes qualidades de radiacao e angulos de incidencia

    Energy Technology Data Exchange (ETDEWEB)

    Santoro, Christiana; Antonio Filho, Joao, E-mail: chsantoro@gmail.com, E-mail: jaf@ufpe.br [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear; Santos, Marcus Aurelio P.; Goncalves Filho, Luiz Carlos, E-mail: masantos@cnen.gov.br, E-mail: l.filho@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, Pe (Brazil)

    2013-07-01

    To use radiation detectors, should periodically perform tests and calibrations on instruments in order to verify its good functionality. One way to ascertain the quality of the instrument is to conduct a study of the angular dependence of the response of the radiation detectors. The photographic dosimetry has been used widely to quantify the radiation doses and to estimate levels of doses received by workers involved with X-and gamma radiation. Photographic dosimeters are used because provide wide range of exposure and good accuracy. One of the sources of error have been introduced by different irradiation geometries between calibration and measurement in radiation fields used in x-ray and gamma ray sources, therefore, there is a need for an evaluation of the sensitivity of dosimeters with variation of the angle of the incident beam. In this study were tested 190 photographic dosemeters in the Metrology Laboratory of the Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE) using the phantom H{sub p} (10), where the dosimeters are evaluated on the basis of the new operational magnitude for individual monitoring, the equivalent personal dose, H{sub p} (10). Angular dependence of these radiation detectors was studied in X radiation fields (in the range of 45 keV energy to 164 keV) and gamma radiation ({sup 137}Cs-662 keV e {sup 60}Co - 1250 keV)

  6. Organ Doses and Effective Doses in Pediatric Radiography: Patient-Dose Survey in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Kiljunen, T.; Tietaevaeinen, A.; Parviainen, T.; Viitala, A.; Kortesniemi, M. (Radiation Practices Regulation, Radiation and Nuclear Safety Authority, Helsinki (Finland))

    2009-01-15

    Background: Use of the effective dose in diagnostic radiology permits the radiation exposure of diverse diagnostic procedures to be quantified. Fundamental knowledge of patient doses enhances the implementation of the 'as low as reasonably achievable' (ALARA) principle. Purpose: To provide comparative information on pediatric examination protocols and patient doses in skull, sinus, chest, abdominal, and pelvic radiography examinations. Material and Methods: 24 Finnish hospitals were asked to register pediatric examination data, including patient information and examination parameters and specifications. The total number of examinations in the study was 1916 (1426 chest, 228 sinus, 96 abdominal, 94 skull, and 72 pelvic examinations). Entrance surface dose (ESD) and dose-area products (DAP) were calculated retrospectively or DAP meters were used. Organ doses and effective doses were determined using a Monte Carlo program (PCXMC). Results: There was considerable variation in examination protocols between different hospitals, indicating large variations in patient doses. Mean effective doses of different age groups ranged from 5 muSv to 14 muSv in skull and sinus examinations, from 25 muSv to 483 muSv in abdominal examinations, and from 6 muSv to 48 muSv in chest examinations. Conclusion: In chest and sinus examinations, the amount of data was extensive, allowing national pediatric diagnostic reference levels to be defined. Parameter selection in pediatric examination protocols should be harmonized in order to reduce patient doses and improve optimization

  7. Derivation of dose conversion factors for tritium

    International Nuclear Information System (INIS)

    Killough, G.G.

    1982-03-01

    For a given intake mode (ingestion, inhalation, absorption through the skin), a dose conversion factor (DCF) is the committed dose equivalent to a specified organ of an individual per unit intake of a radionuclide. One also may consider the effective dose commitment per unit intake, which is a weighted average of organ-specific DCFs, with weights proportional to risks associated with stochastic radiation-induced fatal health effects, as defined by Publication 26 of the International Commission on Radiological Protection (ICRP). This report derives and tabulates organ-specific dose conversion factors and the effective dose commitment per unit intake of tritium. These factors are based on a steady-state model of hydrogen in the tissues of ICRP's Reference Man (ICRP Publication 23) and equilibrium of specific activities between body water and other tissues. The results differ by 27 to 33% from the estimate on which ICRP Publication 30 recommendations are based. The report also examines a dynamic model of tritium retention in body water, mineral bone, and two compartments representing organically-bound hydrogen. This model is compared with data from human subjects who were observed for extended periods. The manner of combining the dose conversion factors with measured or model-predicted levels of contamination in man's exposure media (air, drinking water, soil moisture) to estimate dose rate to an individual is briefly discussed

  8. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Finch, S.M.; McMakin, A.H. (comps.)

    1992-06-01

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is being managed and conducted by the Battelle Pacific Northwest Laboratories under contract with the Centers for Disease Control. The independent Technical Steering Panel (TSP) provides technical direction. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): source terms; environmental transport; environmental monitoring data; demography, food consumption, and agriculture; environmental pathways and dose estimates.

  9. Hanford Environmental Dose Reconstruction Project

    International Nuclear Information System (INIS)

    Finch, S.M.; McMakin, A.H.

    1992-06-01

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is being managed and conducted by the Battelle Pacific Northwest Laboratories under contract with the Centers for Disease Control. The independent Technical Steering Panel (TSP) provides technical direction. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): source terms; environmental transport; environmental monitoring data; demography, food consumption, and agriculture; environmental pathways and dose estimates

  10. Gamma dosimetry of high doses

    International Nuclear Information System (INIS)

    Martinez C, T.; Galvan G, A.; Canizal, G.

    1991-01-01

    The gamma dosimetry of high doses is problematic in almost all the classic dosemeters either based on the thermoluminescence, electric, chemical properties, etc., because they are saturated to very high dose and they are no longer useful. This work carries out an investigation in the interval of high doses. The solid system of heptahydrate ferrous sulfate, can be used as solid dosemeter of routine for high doses of radiation. The proposed method is simple, cheap and it doesn't require sophisticated spectrophotometers or spectrometers but expensive and not common in some laboratories

  11. Hanford Environmental Dose Reconstruction Project

    International Nuclear Information System (INIS)

    Finch, S.M.; McMakin, A.H.

    1991-04-01

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that populations could have received from nuclear operations at Hanford since 1944. The project is being managed and conducted by the Pacific Northwest Laboratory (PNL) under the direction of an independent Technical Steering Panel (TSP). The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from released to impact on humans (dose estimates): source terms; environmental transport; environmental monitoring data; demographics, agriculture, food habits; and, environmental pathways and dose estimates

  12. Prenatal radiation doses from radiopharmaceuticals

    International Nuclear Information System (INIS)

    Rojo, A.M.; Gomez Parada, I.M.; Di Trano, J.L.

    1998-01-01

    The radiopharmaceutical administration with diagnostic or therapeutic purpose during pregnancy implies a prenatal radiation dose. The dose assessment and the evaluation of the radiological risks become relevant due to the great radiosensitivity of the fetal tissues in development. This paper is a revision of the available data for estimating fetal doses in the cases of the more frequently used radiopharmaceuticals in nuclear medicine, taking into account recent investigation in placental crossover. The more frequent diagnostic and therapeutic procedures were analyzed according to the radiation doses implied. (author) [es

  13. Spiral CT and radiation dose

    International Nuclear Information System (INIS)

    Imhof, H.; Schibany, N.; Ba-Ssalamah, A.; Czerny, C.; Hojreh, A.; Kainberger, F.; Krestan, C.; Kudler, H.; Noebauer, I.; Nowotny, R.

    2003-01-01

    Recent studies in the USA and Europe state that computed tomography (CT) scans compromise only 3-5% of all radiological exams, but they contribute 35-45% of total radiation dose to the patient population. These studies lead to concern by several public authorities. Basis of CT-dose measurements is the computed tomography dose index (CTDI), which was established 1981. Nowadays there are several modifications of the CTDI values, which may lead to confusion. It is suggested to use the standardized CTDI-100 w. value together with the dose length product in all CT-examinations. These values should be printed on all CT-images and allows an evaluation of the individualized patient dose. Nowadays, radiologist's aim must be to work at the lowest maximal diagnostic acceptable signal to noise ratio. To decrease radiation dose radiologist should use low kV and mA, but high pitches. Newly developed CT-dose-reduction soft-wares and filters should be installed in all CT-machines. We should critically compare the average dose used for a specific examination with the reference dose used in this country and/or Europe. Greater differences should caution the radiologist. Finally, we as radiologists must check very carefully all indications and recommend alternative imaging methods. But we have also to teach our customers--patients and medical doctors who are non-radiologists--that a 'good' image is not that which show all possible information, but that which visualize 'only' the diagnostic necessary information

  14. Occupational dose trends in Tanzania

    International Nuclear Information System (INIS)

    Muhogora, W.E.; Nyanda, A.M.; Ngaile, J.E.; Lema, U.S.

    1998-01-01

    This paper describes the present status of occupational radiation exposure of monitored workers in Tanzania from 1986 to 1997. The analysis of dose records observes over this period, a fluctuating trend both in the individual and collective doses. The trend is more related to the fluctuations of the number of radiation workers than to the possible radiation safety changes of the working conditions. It has been found that, the maximum annual dose for the worker in all work categories was about 18 mSv y -1 . This suggests that the occupational radiation exposure in all practices satisfies the current dose limitation system. The national exposure summary shows that, the highest collective dose of 12.8 man-Sv which is 90% of the total collective dose, was due to medical applications. The applications in industry and research had a contribution of nearly 0.8 and 0.7 man-Sv respectively. From the professional point of view, the medical diagnostic radiographers received the highest collective dose of 11.2 man-Sv. Although the medical physicists recorded the minimum collective dose of nearly 0.07 man-Sv, the data shows that this profession received the highest mean dose of about 33 mSv in 12 years. Some achievements of the personnel monitoring services and suggestions for future improvement are pointed out. (author)

  15. The Effect of Low‑Dose Ketamine (Preemptive Dose) on ...

    African Journals Online (AJOL)

    The Effect of Low‑Dose Ketamine (Preemptive Dose) on Postcesarean. Section Pain Relief. Forozan Milani, Katayoun Haryalchi, Seyedeh Hajar Sharami, Roya Faraji, Maryam Asgharnia, Fatemeh Salamat1,. Seyedeh Saeedeh Hashemi. Reproductive Health Research Center, Alzahra Hospital, School of Medicine, 1Guilan ...

  16. Do dose area product meter measurements reflect radiation doses ...

    African Journals Online (AJOL)

    Enrique

    between radiation doses absorbed by health care workers and dose area product meter (DAP) measurements at Universitas Hospital, Bloemfontein. The DAP is an instrument which accurately measures the radiation emitted from the source. The study included the interventional radiolo- gists, radiographers and nurses ...

  17. Low doses effects and gamma radiations low dose rates

    International Nuclear Information System (INIS)

    Averbeck, D.

    1999-01-01

    This expose wishes for bringing some definitions and base facts relative to the problematics of low doses effects and low dose rates effects. It shows some already used methods and some actual experimental approaches by focusing on the effects of ionizing radiations with a low linear energy transfer. (N.C.)

  18. Pathogenic effects of low dose irradiation: dose-effect relationships

    International Nuclear Information System (INIS)

    Masse, R.

    2002-01-01

    There is no evidence of pathogenic effects in human groups exposed to less than 100 mSv at low dose-rate. The attributed effects are therefore the result of extrapolations from higher doses. The validity of such extrapolations is discussed from the point of view of epidemiology as well as cellular and molecular biology. The Chernobyl accident resulted in large excess of thyroid cancers in children; it also raised the point that some actual sanitary effects among distressed populations might be a direct consequence of low doses. Studies under the control of UN have not confirmed this point identifying no dose-effect relationship and 'severe socio-economic and psychological pressures... poverty, poor diet and living conditions, and lifestyle factors' as the main cause for depressed health. Some hypothesis are considered for explaining the dose-dependence and high prevalence of non-cancer causes of death among human groups exposed to more than 300 mSv. (author)

  19. Comparison of conversion coefficients for equivalent dose in terms of air kerma for photons using a male adult voxel simulator in sitting and standing posture with geometry of irradiation antero-posterior

    International Nuclear Information System (INIS)

    Galeano, D.C.; Cavalcante, F.R.; Carvalho, A.B.; Hunt, J.

    2014-01-01

    The dose conversion coefficient (DCC) is important to quantify and assess effective doses associated with medical, professional and public exposures. The calculation of DCCs using anthropomorphic simulators and radiation transport codes is justified since in-vivo measurement of effective dose is extremely difficult and not practical for occupational dosimetry. DCCs have been published by the ICRP using simulators in a standing posture, which is not always applicable to all exposure scenarios, providing an inaccurate dose estimation. The aim of this work was to calculate DCCs for equivalent dose in terms of air kerma (H/Kair) using the Visual Monte Carlo (VMC) code and the VOXTISS8 adult male voxel simulator in sitting and standing postures. In both postures, the simulator was irradiated by a plane source of monoenergetic photons in antero-posterior (AP) geometry. The photon energy ranged from 15 keV to 2 MeV. The DCCs for both postures were compared and the DCCs for the standing simulator were higher. For certain organs, the difference of DCCs were more significant, as in gonads (48% higher), bladder (16% higher) and colon (11% higher). As these organs are positioned in the abdominal region, the posture of the anthropomorphic simulator modifies the form in which the radiation is transported and how the energy is deposited. It was also noted that the average percentage difference of conversion coefficients was 33% for the bone marrow, 11% for the skin, 13% for the bone surface and 31% for the muscle. For other organs, the percentage difference of the DCCs for both postures was not relevant (less than 5%) due to no anatomical changes in the organs of the head, chest and upper abdomen. We can conclude that is important to obtain DCCs using different postures from those present in the scientific literature. - Highlights: • Scenarios of external photon exposures were performed in VMC code. • The VOXTISS8 simulator was irradiated in standing and sitting postures.

  20. Applying the 'general principles of dose calculation' (ABG) in practice. Pt. 1

    International Nuclear Information System (INIS)

    Haubelt, R.

    1985-01-01

    Radiation doses are to be calculated for the main exposure pathways such as gamma submersion, beta submersion, gamma radiation at ground level, inhalation and ingestion of radionuclides. After the amendment of the German Radiation Protection Ordinance to include the latest ICRP Recommendations, the dose to be determined now is the effective dose equivalent, replacing the former whole-body dose equivalent. (DG) [de

  1. Radiation doses and risks from internal emitters

    International Nuclear Information System (INIS)

    Harrison, John; Day, Philip

    2008-01-01

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

  2. 222Rn alpha dose to organs other than lung

    International Nuclear Information System (INIS)

    Harley, N.H.; Robbins, E.S.

    1991-01-01

    The alpha dose to cells in tissues or organs other theft the lung has been calculated using the solubility coefficients for 222 Rn measured in human tissue. The annual alpha dose equivalent f rom 222 Rn and decay products in most tissues is a maximum of 30% of the annual average natural background dose equivalent (1 mSv) for external and internally deposited nuclides. The dose to the small population of lymphocytes located in or under the bronchial epithelium is a special case and their annual dose equivalent is essentially the same as that to basal cells in bronchial epithelium (200 mSv) for continuous exposure to 200 Bq M -3 . The significance of this dose is uncertain because the only excess cancer observed in follow up studies of underground miners with high 222 Rn exposure is bronchogenic carcinoma

  3. Assessment of radiation dose awareness among pediatricians

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Karen E.; Parnell-Parmley, June E.; Charkot, Ellen; BenDavid, Guila; Krajewski, Connie [The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto, Ontario (Canada); Haidar, Salwa [Mubarak Al-Kabeer Hospital, Department of Radiology, Salmiya (Kuwait); Moineddin, Rahim [University of Toronto, Department of Family and Community Medicine, Toronto (Canada)

    2006-08-15

    There is increasing awareness among pediatric radiologists of the potential risks associated with ionizing radiation in medical imaging. However, it is not known whether there has been a corresponding increase in awareness among pediatricians. To establish the level of awareness among pediatricians of the recent publicity on radiation risks in children, knowledge of the relative doses of radiological investigations, current practice regarding parent/patient discussions, and the sources of educational input. Multiple-choice survey. Of 220 respondents, 105 (48%) were aware of the 2001 American Journal of Roentgenology articles on pediatric CT and radiation, though only 6% were correct in their estimate of the quoted lifetime excess cancer risk associated with radiation doses equivalent to pediatric CT. A sustained or transient increase in parent questioning regarding radiation doses had been noticed by 31%. When estimating the effective doses of various pediatric radiological investigations in chest radiograph (CXR) equivalents, 87% of all responses (and 94% of CT estimates) were underestimates. Only 15% of respondents were familiar with the ALARA principle. Only 14% of pediatricians recalled any relevant formal teaching during their specialty training. The survey response rate was 40%. Awareness of radiation protection issues among pediatricians is generally low, with widespread underestimation of relative doses and risks. (orig.)

  4. Assessment of radiation dose awareness among pediatricians

    International Nuclear Information System (INIS)

    Thomas, Karen E.; Parnell-Parmley, June E.; Charkot, Ellen; BenDavid, Guila; Krajewski, Connie; Haidar, Salwa; Moineddin, Rahim

    2006-01-01

    There is increasing awareness among pediatric radiologists of the potential risks associated with ionizing radiation in medical imaging. However, it is not known whether there has been a corresponding increase in awareness among pediatricians. To establish the level of awareness among pediatricians of the recent publicity on radiation risks in children, knowledge of the relative doses of radiological investigations, current practice regarding parent/patient discussions, and the sources of educational input. Multiple-choice survey. Of 220 respondents, 105 (48%) were aware of the 2001 American Journal of Roentgenology articles on pediatric CT and radiation, though only 6% were correct in their estimate of the quoted lifetime excess cancer risk associated with radiation doses equivalent to pediatric CT. A sustained or transient increase in parent questioning regarding radiation doses had been noticed by 31%. When estimating the effective doses of various pediatric radiological investigations in chest radiograph (CXR) equivalents, 87% of all responses (and 94% of CT estimates) were underestimates. Only 15% of respondents were familiar with the ALARA principle. Only 14% of pediatricians recalled any relevant formal teaching during their specialty training. The survey response rate was 40%. Awareness of radiation protection issues among pediatricians is generally low, with widespread underestimation of relative doses and risks. (orig.)

  5. Dose computation for therapeutic electron beams

    Science.gov (United States)

    Glegg, Martin Mackenzie

    The accuracy of electron dose calculations performed by two commercially available treatment planning computers, Varian Cadplan and Helax TMS, has been assessed. Measured values of absorbed dose delivered by a Varian 2100C linear accelerator, under a wide variety of irradiation conditions, were compared with doses calculated by the treatment planning computers. Much of the motivation for this work was provided by a requirement to verify the accuracy of calculated electron dose distributions in situations encountered clinically at Glasgow's Beatson Oncology Centre. Calculated dose distributions are required in a significant minority of electron treatments, usually in cases involving treatment to the head and neck. Here, therapeutic electron beams are subject to factors which may cause non-uniformity in the distribution of dose, and which may complicate the calculation of dose. The beam shape is often irregular, the beam may enter the patient at an oblique angle or at an extended source to skin distance (SSD), tissue inhomogeneities can alter the dose distribution, and tissue equivalent material (such as wax) may be added to reduce dose to critical organs. Technological advances have allowed the current generation of treatment planning computers to implement dose calculation algorithms with the ability to model electron beams in these complex situations. These calculations have, however, yet to be verified by measurement. This work has assessed the accuracy of calculations in a number of specific instances. Chapter two contains a comparison of measured and calculated planar electron isodose distributions. Three situations were considered: oblique incidence, incidence on an irregular surface (such as that which would be arise from the use of wax to reduce dose to spinal cord), and incidence on a phantom containing a small air cavity. Calculations were compared with measurements made by thermoluminescent dosimetry (TLD) in a WTe electron solid water phantom. Chapter

  6. Dose calculation of anticancer drugs

    NARCIS (Netherlands)

    Gao, Bo; Klumpen, Heinz-Josef; Gurney, Howard

    2008-01-01

    BACKGROUND: Anticancer drugs are characterized by a narrow therapeutic window and significant inter-patient variability in therapeutic and toxic effects. Current body surface area (BSA)-based dosing fails to standardize systemic anticancer drug exposure and other alternative dosing strategies also

  7. Time and dose in carcinogenesis

    International Nuclear Information System (INIS)

    Mayneord, W.V.; Clarke, R.H.

    1978-05-01

    Previous work on the implications of different forms of dose response relationships is extended to include time as a variable, not only in time of irradiation but also in the time of appearance of effects following irradiation. The forms of relationships for time distribution of tumours revealed experimentally for both radiation and chemical carcinogens are first considered. It appears that much data may be correlated in terms of a log-normal distribution of tumour yield following the insult. Further, it is noted, that there is evidence that the median time of tumour appearance may be a function of total dose received or even of dose rate for protracted exposure. Using numerical values of these parameters derived from the biological literature speculative studies have been made of the effects on dose response relationships of using a time distribution of tumour yield, considering both uniform irradiation and point sources. In addition the effects of using dose rate rather than dose to define the log-normal distribution to tumour appearance have been investigated. It is assumed that biological response is directly proportional to dose but that effect is distributed in time. From this linear assumption the appearance of non-linear dose response relationships and apparent thresholds are continually seen. Finally, both the importance of attempting analyses of biological data in terms of stochastic concepts and the need for biological data to test our hypotheses is emphasised. (author)

  8. EPA's Benchmark Dose Modeling Software

    Science.gov (United States)

    The EPA developed the Benchmark Dose Software (BMDS) as a tool to help Agency risk assessors facilitate applying benchmark dose (BMD) method’s to EPA’s human health risk assessment (HHRA) documents. The application of BMD methods overcomes many well know limitations ...

  9. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Finch, S.M. (comp.)

    1990-09-01

    This monthly report summarizes the technical progress and project status for the Hanford Environmental Dose Reconstruction (HEDR) Project being conducted at the Pacific Northwest Laboratory (PNL) under the direction of a Technical Steering Panel (TSP). The TSP is composed of experts in numerous technical fields related to this project and represents the interests of the public. The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): source terms, environmental transport, environmental monitoring data, demographics, agriculture, food habits, environmental pathways and dose estimates. 3 figs.

  10. Labour cost of radiation dose

    International Nuclear Information System (INIS)

    Cook, A.; Lockett, L.E.

    1978-01-01

    In order to optimise capital expenditure on measures to protect workers against radiation it would be useful to have a means to measure radiation dose in money terms. Because labour has to be employed to perform radiation work there must be some relationship between the wages paid and the doses received. Where the next increment of radiation dose requires additional labour to be recruited the cost will at least equal the cost of the extra labour employed. This paper examines some of the factors which affect the variability of the labour cost of radiation dose and notes that for 'in-plant' exposures the current cost per rem appears to be significantly higher than values quoted in ICRP Publication 22. An example is given showing how this concept may be used to determine the capital it is worth spending on installed plant to prevent regular increments of radiation dose to workers. (author)

  11. Dose optimisation in computed radiography

    International Nuclear Information System (INIS)

    Schreiner-Karoussou, A.

    2005-01-01

    After the installation of computed radiography (CR) systems in three hospitals in Luxembourg a patient dose survey was carried out for three radiographic examinations, thorax, pelvis and lumbar spine. It was found that the patient doses had changed in comparison with the patient doses measured for conventional radiography in the same three hospitals. A close collaboration between the manufacturers of the X-ray installations, the CR imaging systems and the medical physicists led to the discovery that the speed class with which each radiographic examination was to be performed, had been ignored, during installation of the digital imaging systems. A number of procedures were carried out in order to calibrate and program the X-ray installations in conjunction with the CR systems. Following this optimisation procedure, a new patient dose survey was carried out for the three radiographic examinations. It was found that patient doses for the three hospitals were reduced. (authors)

  12. Bone and marrow dose modeling

    International Nuclear Information System (INIS)

    Stabin, Michael G.

    2004-01-01

    Nuclear medicine therapy is being used increasingly in the treatment of cancer (thyroid, leukemia/lymphoma with RIT, primary and secondary bone malignancies, and neuroblastomas). In all cases it is marrow toxicity that limits the amount of treatment that can be administered safely. Marrow dose calculations are more difficult than for many major organs because of the intricate association of bone and soft tissue elements. In RIT, there appears to be no consensus on how to calculate that dose accurately, or of individual patients ability to tolerate planned therapy. Available dose models are designed after an idealized average, healthy individual. Patient-specific methods are applied in evaluation of biokinetic data, and need to be developed for treatment of the physical data (dose conversion factors) as well: age, prior patient therapy, disease status. Contributors to marrow dose: electrons and photons

  13. Measurement of conversion coefficients between air Kerma and personal dose equivalent and backscatter factors for diagnostic X-ray beams; Determinacao experimental dos coeficientes de conversao de Kerma no ar para o equivalente de dose pessoal, Hp(d), e fatores de retroespalhamento em feixes de raios-x diagnostico

    Energy Technology Data Exchange (ETDEWEB)

    Rosado, Paulo Henrique Goncalves

    2008-07-01

    Two sets of quantities are import in radiological protection: the protection and operational quantities. Both sets can be related to basic physical quantities such as kerma through conversion coefficients. For diagnostic x-ray beams the conversion coefficients and backscatter factors have not been determined yet, those parameters are need for calibrating dosimeters that will be used to determine the personal dose equivalent or the entrance skin dose. Conversion coefficients between air kerma and personal dose equivalent and backscatter factors were experimentally determined for the diagnostic x-ray qualities RQR and RQA recommended by the International Electrotechnical Commission (IEC). The air kerma in the phantom and the mean energy of the spectrum were measured for such purpose. Harshaw LiF-100H thermoluminescent dosemeters (TLD) were used for measurements after being calibrated against an 180 cm{sup 3} Radcal Corporation ionization chamber traceable to a reference laboratory. A 300 mm x 300 mm x 150 mm polymethylmethacrylate (PMMA) slab phantom was used for deep-dose measurements. Tl dosemeters were placed in the central axis of the x-ray beam at 5, 10, 15, 25 and 35 mm depth in the phantom upstream the beam direction Another required parameter for determining the conversion coefficients from was the mean energy of the x-ray spectrum. The spectroscopy of x-ray beams was done with a CdTe semiconductor detector that was calibrated with {sup 133} Ba, {sup 241} Am and {sup 57} Co radiation sources. Measurements of the x-ray spectra were carried out for all RQR and RQA IEC qualities. Corrections due to the detector intrinsic efficiency, total energy absorption, escape fraction of the characteristic x-rays, Compton effect and attenuation in the detector were done aiming an the accurate determination of the mean energy. Measured x-ray spectra were corrected with the stripping method by using these response functions. The typical combined standard uncertainties of

  14. Multilayer detector for skin absorbed dose measuring

    International Nuclear Information System (INIS)

    Osanov, D.P.; Panova, V.P.; Shaks, A.I.

    1985-01-01

    A method for skin dosimetry based on utilization of multilayer detectors and permitting to estimate distribution of absorbed dose by skin depth is described. The detector represents a set of thin sensitive elements separated by tissue-equivalent absorbers. Quantitative evaluation and forecasting the degree of radiation injury of skin are determined by the formula based on determination of the probability of the fact that cells are not destroyed and they can divide further on. The given method ensures a possibility of quantitative evaluation of radiobiological effect and forecasting clinical consequences of skin irradiation by results of corresponding measurements of dose by means of the miultilayer detector

  15. Establishment Of Dose Correlation During Dose Mapping On Medical Devices

    International Nuclear Information System (INIS)

    Ruzalina Baharin; Hasan Sham; Ahsanulkhaliqin Abdul Wahab

    2014-01-01

    This paper explains the work done during product dose mapping in order to get the correlation between doses at MINTec-Sinagama plant. Product used was medical devices in aluminium tubes packaged in cardboard kegs packaging with average weight of 12 kg per carton. 12 cartons were loaded in every one tote to give 0.2 g/ cm 3 of density. Ceric cerous dosimeters were placed at specific locations as indicated in SP14: Product Dose Mapping, QMS of MINTec-Sinagama around three planes. Three processes were made at different days as a three replicates to show the reproducibility of measurements. (author)

  16. Dosimetric systems of high dose, dose rate and dose uniformity in food and medical products

    International Nuclear Information System (INIS)

    Vargas, J.; Vivanco, M.; Castro, E.

    2014-08-01

    In the Instituto Peruano de Energia Nuclear (IPEN) we use the chemical dosimetry Astm-E-1026 Fricke as a standard dosimetric system of reference and different routine dosimetric systems of high doses, according to the applied doses to obtain the desired effects in the treated products and the doses range determined for each type of dosimeter. Fricke dosimetry is a chemical dosimeter in aqueous solution indicating the absorbed dose by means an increase in absorbance at a specific wavelength. A calibrated spectrophotometer with controlled temperature is used to measure absorbance. The adsorbed dose range should cover from 20 to 400 Gy, the Fricke solution is extremely sensitive to organic impurities, to traces of metal ions, in preparing chemical products of reactive grade must be used and the water purity is very important. Using the referential standard dosimetric system Fricke, was determined to March 5, 2013, using the referential standard dosimetric system Astm-1026 Fricke, were irradiated in triplicate Fricke dosimeters, to 5 irradiation times (20; 30; 40; 50 and 60 seconds) and by linear regression, the dose rate of 5.400648 kGy /h was determined in the central point of the irradiation chamber (irradiator Gamma cell 220 Excel), applying the decay formula, was compared with the obtained results by manufacturers by means the same dosimetric system in the year of its manufacture, being this to the date 5.44691 kGy /h, with an error rate of 0.85. After considering that the dosimetric solution responds to the results, we proceeded to the irradiation of a sample of 200 g of cereal instant food, 2 dosimeters were placed at the lateral ends of the central position to maximum dose and 2 dosimeters in upper and lower ends as minimum dose, they were applied same irradiation times; for statistical analysis, the maximum dose rate was 6.1006 kGy /h and the minimum dose rate of 5.2185 kGy /h; with a dose uniformity of 1.16. In medical material of micro pulverized bone for

  17. Comparison of conversion coefficients for equivalent dose in terms of air kerma using a sitting and standing female adult voxel simulators exposure to photons in antero-posterior irradiation geometry

    International Nuclear Information System (INIS)

    Cavalcante, F.R.; Galeano, D.C.; Carvalho Júnior, A.B.; Hunt, J.

    2014-01-01

    Due to the difficulty in implementing invasive techniques for calculations of dose for some exposure scenarios, computational simulators have been created to represent as realistically as possible the structures of the human body and through radiation transport simulations to obtain conversion coefficients (CCs) to estimate dose. In most published papers simulators are implemented in the standing posture and this may not describe a real scenario of exposure. In this work we developed exposure scenarios in the Visual Monte Carlo (VMC) code using a female simulator in standing and sitting postures. The simulator was irradiated in the antero-posterior (AP) geometry by a plane source of monoenergetic photons with energy from 10 keV to 2 MeV. The conversion coefficients for equivalent dose in terms of air kerma (H T /K air ) were calculated for both scenarios and compared. The results show that the percentage difference of CCs for the organs of the head and thorax was not significant (less than 5%) since the anatomic position of the organs is the same in both postures. The percentage difference is more significant to the ovaries (71% for photon energy of 20 keV), to the bladder (39% at 60 keV) and to the uterus (37% at 100 keV) due to different processes of radiation interactions in the legs of the simulator when its posture is changed. For organs and tissues that are distributed throughout the entire body, such as bone (21% at 100 keV) and muscle (30% at 80 keV) the percentage difference of CCs reflects a reduction of interaction of photons with the legs of the simulator. Therefore, the calculation of conversion coefficients using simulators in the sitting posture is relevant for a more accurate dose estimation in real exposures to radiation. - Highlights: ► Scenarios of external photon exposures were performed in VMC code. ► The FAX simulator was irradiated in sitting and standing postures. ► The irradiation geometry used was the antero-posterior (AP). ► The

  18. Patient dose in neonatal units

    International Nuclear Information System (INIS)

    Smans, K.; Struelens, L.; Smet, M.; Bosmans, H.; Vanhavere, F.

    2008-01-01

    Lung disease represents one of the most life-threatening conditions in prematurely born children. In the evaluation of the neonatal chest, the primary and most important diagnostic study is therefore the chest radiograph. Since prematurely born children are very sensitive to radiation, those radiographs may lead to a significant radiation detriment. Hence, knowledge of the patient dose is necessary to justify the exposures. A study to assess the patient doses was started at the neonatal intensive care unit (NICU) of the Univ. Hospital in Leuven. Between September 2004 and September 2005, prematurely born babies underwent on average 10 X-ray examinations in the NICU. In this sample, the maximum was 78 X-ray examinations. For chest radiographs, the median entrance skin dose was 34 μGy and the median dose area product was 7.1 mGy.cm 2 . By means of conversion coefficients, the measured values were converted to organ doses. Organ doses were calculated for three different weight classes: extremely low birth weight infants ( 2500 g). The doses to the lungs for a single chest radiograph for infants with extremely low birth weights, low birth weights and normal birth weights were 24, 25 and 32 μGy, respectively. (authors)

  19. CT doses in cylindrical phantoms

    International Nuclear Information System (INIS)

    Atherton, J.V.; Huda, W.

    1995-01-01

    A single CT scan of thickness T in a cylindrical phantom produces a three-dimensional dose distribution, which depends primarily on the photon energy spectrum, the x-ray beam shaping filter and the size and composition of the irradiated phantom. Monte Carlo simulations employing monoenergetic photons were employed to investigate the effect of each of these factors on phantom dose distributions. The fractional energies scattered, imparted and transmitted through the CT phantom were calculated. A dose index (D(r)), which is a function of phantom radius r, was computed. Phantom materials investigated included lung, fat, water, soft tissue, acrylic and bone with calculations performed for head (160 mm diameter) and body (320 mm diameter) phantoms. All dose and energy imparted data generated for CT phantoms were normalized using an 'in air' dose (D air ), which is defined as the axial dose (in acrylic) at the isocentre in the absence of any phantom. Results obtained show how CT parameters impact on doses in cylindrical phantoms. These dosimetry data are likely to be useful to estimate energy imparted to phantoms (and patients) undergoing CT examinations. (author)

  20. Pharmacokinetically guided dosing of (high-dose) chemotherapeutic agents

    NARCIS (Netherlands)

    Attema-de Jonge, M.E. (Milly Ellen)

    2004-01-01

    Due to variation in drug distribution, metabolism and elimination processes between patients, systemic exposure to chemotherapeutic agents may be highly variable from patient to patient after administration of similar doses. This pharmacokinetic variability may explain in part the large variability

  1. Physical requirements for measurement of radiation dose and their relationship to personnel dose meter design and use

    International Nuclear Information System (INIS)

    Chabot, G.E. Jr.; Jimenez, M.A.; Skrable, K.W.

    1978-01-01

    This paper stems from the concerns of the authors with both the design of current personnel dose meters and the interpretation of dose information from them in light of the actual physical requirements to measure dose. These concerns have been reinforced and extended following a comparative study of the responses of particular TLD and film systems and as the result of a recent national survey on personnel dosimetry conducted by the authors. Among the major points discussed are the systems available for penetrating and shallow dose assessment, dose meter calibration, the measurement and interpretation of skin dose, and the deficiencies of neutron albedo dose meters for routine personnel use. Calibration considerations address the questions of whether or not a phantom should be used and the difference in interpretation of responses with and without a phantom; the relationship between calculated and measured doses; and electronic equilibrium considerations in the measurement of photon doses. Matters of importance in relation to skin dose measurement include techniques in use to interpret skin dose from dose meter response; the appropriateness of evaluation of the surface dose to the live skin layer versus the average dose to the live skin layer and the limitations and requirements on dose meter design with respect to the dose being evaluated; and the significance of dose meter response in relationship to currently used beta calibration standards. Regarding the use of TLD albedo type neutron dose meters currently available, considerations are extended to the strong energy spectral dependence of the dose meter response and the possibility of making significant over or underestimations of neutron dose equivalent, depending on the calibration techniques used and the spectral quality encountered. (author)

  2. Effects of low doses; Effet des faibles doses

    Energy Technology Data Exchange (ETDEWEB)

    Le Guen, B. [Electricite de France (EDF-LAM-SCAST), 93 - Saint-Denis (France)

    2001-07-01

    Actually, even though it is comfortable for the risk management, the hypothesis of the dose-effect relationship linearity is not confirmed for any model. In particular, in the area of low dose rate delivered by low let emitters. this hypothesis is debated at the light of recent observations, notably these ones relative to the mechanisms leading to genetic instability and induction eventuality of DNA repair. The problem of strong let emitters is still to solve. (N.C.)

  3. Are low radiation doses Dangerous?

    International Nuclear Information System (INIS)

    Garcia Lima, O.; Cornejo, N.

    1996-01-01

    In the last few years the answers to this questions has been affirmative as well as negative from a radiation protection point of view low doses of ionizing radiation potentially constitute an agent causing stochasting effects. A lineal relation without threshold is assumed between dose and probability of occurrence of these effects . Arguments against the danger of probability of occurrence of these effects. Arguments again the danger of low dose radiation are reflected in concepts such as Hormesis and adaptive response, which are phenomena that being studied at present

  4. Characterization of thermal neutron fields for calibration of neutron monitors in accordance with great equivalent dose environment H⁎(10); Caracterização de campos de nêutrons térmicos para a calibração de monitores de nêutrons em termos da grandeza equivalente de dose ambiente H⁎(10)

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Larissa P. S. da; Silva, Felipe S.; Fonseca, Evaldo S.; Patrao, Karla C.S.; Pereira, Walsan W. [Instituto de Radioproteção e Dosimetria (LNMRI/IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Laboratório Nacional de Metrologia das Radiações Ionizantes; Astuto, Achilles, E-mail: larissapaizante@poli.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    The Laboratório Brasileiro de Nêutrons do Instituto de Radioproteção e Dosimetria (IRD/CNEN) has developed and built a thermal neutron flux facility to provide neutron fluence for dosimeters (Astuto, 2014). This fluency is obtained by four 16 Ci sources {sup 241}AmBe (α, n) positioned around the channel positioned in the center of the Thermal Flow Unit (UFT). The UFT was built with blocks of paraffin with graphite addition and graphite blocks of high purity to obtain a central field with a homogeneous thermal neutron fluence for calibration purposes with the following measurements: 1.2 x 1.2 x 1.2 m{sup 3}. The objective of this work is to characterize several points, in the thermal energy range, in terms of the equivalent ambient dose quantity H⁎(10) for calibration and irradiation of monitors neutrons.

  5. Hybrid dose calculation: a dose calculation algorithm for microbeam radiation therapy

    Science.gov (United States)

    Donzelli, Mattia; Bräuer-Krisch, Elke; Oelfke, Uwe; Wilkens, Jan J.; Bartzsch, Stefan

    2018-02-01

    Microbeam radiation therapy (MRT) is still a preclinical approach in radiation oncology that uses planar micrometre wide beamlets with extremely high peak doses, separated by a few hundred micrometre wide low dose regions. Abundant preclinical evidence demonstrates that MRT spares normal tissue more effectively than conventional radiation therapy, at equivalent tumour control. In order to launch first clinical trials, accurate and efficient dose calculation methods are an inevitable prerequisite. In this work a hybrid dose calculation approach is presented that is based on a combination of Monte Carlo and kernel based dose calculation. In various examples the performance of the algorithm is compared to purely Monte Carlo and purely kernel based dose calculations. The accuracy of the developed algorithm is comparable to conventional pure Monte Carlo calculations. In particular for inhomogeneous materials the hybrid dose calculation algorithm out-performs purely convolution based dose calculation approaches. It is demonstrated that the hybrid algorithm can efficiently calculate even complicated pencil beam and cross firing beam geometries. The required calculation times are substantially lower than for pure Monte Carlo calculations.

  6. Application of ICRP recommendations relevant to internal dose

    International Nuclear Information System (INIS)

    Cowser, K.E.; Snyder, W.S.; Struxness, E.G.

    1969-01-01

    The intent of this paper is to review several of the basic concepts of radiation protection (with emphasis on internal dose) currently recommended by the International Commission on radiological Protection (ICRP), to summarize the assumptions and methods used in the calculation of internal dose, and to illustrate by example the practical application of the pertinent guidelines. Two broad subject areas are considered: (1) standards of radiation protection and (2) bases of internal dose estimation. Topics discussed within the framework of radiation protection standards include maximum permissible dose, categories of radiation exposure, maximum permissible dose commitment, simultaneous internal and external exposure, multiple organ exposure, and size of the exposed group. Discussion of internal dose estimation is limited to selected items that include the body burden of radionuclides and the calculation of absorbed dose, the dose equivalent, the derivation of maximum permissible concentration (MPC), the relationship of stable element intake to the MPC, and short term and chronic exposure situations. (author)

  7. Patient radiation dose in conventional and xerographic cephalography

    International Nuclear Information System (INIS)

    Copley, R.L.; Glaze, S.A.; Bushong, S.C.; West, D.C.

    1979-01-01

    A comparison of the radiation doses for xeroradiographic and conventional film screen cephalography was made. Alderson tissue-equivalent phantoms were used for patient simulation. An optimum technique in terms of patient dose and image quality indicated that the dose for the Xerox process ranged from five to eleven times greater than that for the conventional process for entrance and exit exposures, respectively. This dose, however, falls within an acceptable range for other dental and medical radiation doses. It is recommended that conventional cephalography be used for routine purposes and that xeroradiography be reserved for situations requiring the increased image quality that the process affords

  8. Evaluation of effective doses and population doses for computed tomography exposure in Taiwan

    International Nuclear Information System (INIS)

    Yeh, S.H.; Hsu, W.J.; Hsiao, H.S.

    2000-01-01

    As estimated, more than 80% of the man-made radiation dose is derived from medical applications, particularly from diagnostic treatment. Therefore, evaluating the radiation dose from diagnostic treatments is very important. The purpose of this study is to investigate the organ dose distribution and the effective doses from brain, chest and abdomen CT examinations. The organ equivalent dose and effective dose of patients were evaluated by exposing a male RANDO phantom to CT X-ray. Dose distributions in various organs were investigated using TLD LiF:Mg,Ti powder. A total of 224 TLDs were embedded in various organs of the phantom for each CT exposure. The organs that were monitored included bladder, bone marrow, breast, colon, liver, long, oesophagus, skin, stomach, thyroid and tests. The effective doses were calculated with reference to the tissue weighting factors recommended by the ICRP 60 report. Experimental TLDs were carefully calibrated using a secondary standard ionization chamber and a special X-ray machine, before they were exposed at hospitals. Taiwanese hospitals are classified as medical centers, area hospitals and local hospitals. This study investigated one hospital in each category. The experiments were performed according to the parameters (kVp, mAs) and procedures used in actual clinical examinations. In addition, this investigation also adopted the statistical mean and median parameters that obtained by a nationwide questionnaire methods in 1993 for it's CT X-ray exposure experiments. The organ doses significantly affected by the exposed region, i.e., brain, chest or abdomen. The effective doses were in the range of 0.93 to 2.41 mSv, 2.96 to 14.53 mSv and 4.55 to 12.30 mSv for brain, chest and abdomen exposure respectively. The investigated hospitals showed wide range of effective dose to the patients by the reasons of different CT machine, different exposure parameters (kVp, mAs) and different treatment procedures. This is the first time to

  9. The MESORAD dose assessment model: Computer code

    International Nuclear Information System (INIS)

    Ramsdell, J.V.; Athey, G.F.; Bander, T.J.; Scherpelz, R.I.

    1988-10-01

    MESORAD is a dose equivalent model for emergency response applications that is designed to be run on minicomputers. It has been developed by the Pacific Northwest Laboratory for use as part of the Intermediate Dose Assessment System in the US Nuclear Regulatory Commission Operations Center in Washington, DC, and the Emergency Management System in the US Department of Energy Unified Dose Assessment Center in Richland, Washington. This volume describes the MESORAD computer code and contains a listing of the code. The technical basis for MESORAD is described in the first volume of this report (Scherpelz et al. 1986). A third volume of the documentation planned. That volume will contain utility programs and input and output files that can be used to check the implementation of MESORAD. 18 figs., 4 tabs

  10. Use of the Concept of Equivalent Biologically Effective Dose (BED) to Quantify the Contribution of Hyperthermia to Local Tumor Control in Radiohyperthermia Cervical Cancer Trials, and Comparison With Radiochemotherapy Results

    International Nuclear Information System (INIS)

    Plataniotis, George A.; Dale, Roger G.

    2009-01-01

    Purpose: To express the magnitude of contribution of hyperthermia to local tumor control in radiohyperthermia (RT/HT) cervical cancer trials, in terms of the radiation-equivalent biologically effective dose (BED) and to explore the potential of the combined modalities in the treatment of this neoplasm. Materials and Methods: Local control rates of both arms of each study (RT vs. RT+HT) reported from randomized controlled trials (RCT) on concurrent RT/HT for cervical cancer were reviewed. By comparing the two tumor control probabilities (TCPs) from each study, we calculated the HT-related log cell-kill and then expressed it in terms of the number of 2 Gy fraction equivalents, for a range of tumor volumes and radiosensitivities. We have compared the contribution of each modality and made some exploratory calculations on the TCPs that might be expected from a combined trimodality treatment (RT+CT+HT). Results: The HT-equivalent number of 2-Gy fractions ranges from 0.6 to 4.8 depending on radiosensitivity. Opportunities for clinically detectable improvement by the addition of HT are only available in tumors with an alpha value in the approximate range of 0.22-0.28 Gy -1 . A combined treatment (RT+CT+HT) is not expected to improve prognosis in radioresistant tumors. Conclusion: The most significant improvements in TCP, which may result from the combination of RT/CT/HT for locally advanced cervical carcinomas, are likely to be limited only to those patients with tumors of relatively low-intermediate radiosensitivity.

  11. CONDOS-II, Radiation Dose from Consumer Product Distribution Chain

    International Nuclear Information System (INIS)

    1984-01-01

    1 - Description of problem or function: This code was developed under sponsorship of the Nuclear Regulatory Commission to serve as a tool for assessing radiation doses that may be associated with consumer products that contain radionuclides. The code calculates radiation dose equivalents resulting from user-supplied scenarios of exposures to radionuclides contained in or released from sources that contain radionuclides. Dose equivalents may be calculated to total body, skin surface, skeletal bone, testes, ovaries, liver, kidneys, lungs, and maximally exposed segments of the gastrointestinal tract from exposures via (1) direct, external irradiation by photons (including Bremsstrahlung) emitted from the source, (2) external irradiation by photons during immersion in air containing photon-emitting radionuclides that have escaped from the source, (3) internal exposures by all radiations emitted by inhaled radionuclides that have escaped from the source, and (4) internal exposures by all radiations emitted by ingested radionuclides that have escaped from the source. 2 - Method of solution: Organ dose equivalents are approximated in two ways, depending on the exposure type. For external exposures, energy specific organ-to-skin-surface dose conversion ratios are used to approximate dose equivalents to specific organs from doses calculated to a point on the skin surface. The organ-to-skin ratios are incorporated in organ- and nuclide-specific dose rate factors, which are used to approximate doses during immersion in contaminated air. For internal exposures, 50 year dose equivalents are calculated using organ- and nuclide-specific, 50 year dose conversion factors. Doses from direct, external exposures are calculated using the energy-specific dose conversion ratios, user supplied exposure conditions, and photon flux approximations for eleven source geometries. Available source geometries include: point, shielded and unshielded; line, shielded and unshielded; disk, shielded

  12. Patient dose in interventional radiology

    International Nuclear Information System (INIS)

    Fernandez Bordes, M.; Berenguer, R.; Gomez, P.; Bejar, M.J.; Gonzalez, S.

    2001-01-01

    This paper presents the estimation of dose-area product (DAP) received by 128 patients during different interventional radiological procedures in the Hospital Universitario de Salamanca, analyzing the differences between procedures classified as either vascular, non vascular, diagnostic or therapeutic. These differences can be assessed and reference dose levels can be established as a function of the variation of those parameters. Comparisons between dose-area product values obtained from this study are made with the data from nine other patient dose surveys, although explanations for some of the differences could not be obtained in some cases. The reference values in these procedures in our centre are very high due to a great number of images, so the clinical protocol should be changed to avoid this problem. (author)

  13. Doses from Medical Radiation Sources

    Science.gov (United States)

    ... York Northern California Northern Ohio Rio Grande Savannah River State of Texas Southern California Susquehanna Valley Virginia ... patient's metabolism), and other issues. Typical Doses from Diagnostic Radiology Exams As noted above, the tables below ...

  14. Dose from drinking water Finland

    International Nuclear Information System (INIS)

    Maekelaeinen, Ilona; Salonen, Laina; Huikuri, Pia; Arvela, Hannu

    1999-01-01

    The dose from drinking water originates almost totally from naturally occurring radionuclides in the uranium-238 series, the most important nuclide being radon-222. Second comes lead-210, and third polonium-210. The mean age-group-weighted dose received by ingestion of drinking water is 0.14 mSv per year. More than half of the total cumulative dose of 750 manSv is received by the users of private wells, forming 13% of the population. The most exposed group comprises the users of wells drilled in bedrock, who receive 320 manSv while comprising only 4% of the population. The calculated number of annual cancer incidences due to drinking water is very sensitive to the dose-conversion factors of ingested radon used, as well as to the estimated lung cancer incidences caused by radon released from water into indoor air. (au)

  15. Hanford Environmental Dose Reconstruction Project

    International Nuclear Information System (INIS)

    McMakin, A.H.; Cannon, S.D.; Finch, S.M.

    1992-07-01

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The TSP consists of experts in environmental pathways, epidemiology, surface-water transport, ground-water transport, statistics, demography, agriculture, meteorology, nuclear engineering, radiation dosimetry, and cultural anthropology. Included are appointed technical members representing the states of Oregon, Washington, and Idaho, a representative of Native American tribes, and an individual representing the public. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impact on humans (dose estimates): Source terms, environmental transport, environmental monitoring data, demography, food consumption, and agriculture, and environmental pathways and dose estimates. Progress is discussed

  16. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    McMakin, A.H.; Cannon, S.D.; Finch, S.M. (comps.)

    1992-07-01

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The TSP consists of experts in environmental pathways, epidemiology, surface-water transport, ground-water transport, statistics, demography, agriculture, meteorology, nuclear engineering, radiation dosimetry, and cultural anthropology. Included are appointed technical members representing the states of Oregon, Washington, and Idaho, a representative of Native American tribes, and an individual representing the public. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impact on humans (dose estimates): Source terms, environmental transport, environmental monitoring data, demography, food consumption, and agriculture, and environmental pathways and dose estimates. Progress is discussed.

  17. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Finch, S.M.; McMakin, A.H. (comps.)

    1991-01-01

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is being managed and conducted by the Pacific Northwest Laboratory (PNL) under the direction of an independent Technical Steering Panel (TSP). The TSP consists of experts in environmental pathways, epidemiology, surface-water transport, ground-water transport, statistics, demography, agriculture, meteorology, nuclear engineering, radiation dosimetry, and cultural anthropology. Included are appointed technical members representing the states of Oregon and Washington, a representative of Native American tribes, and an individual representing the public. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on human (dose estimates): Source Terms; Environmental Transport; Environmental Monitoring Data; Demographics, Agriculture, Food Habits and; Environmental Pathways and Dose Estimates.

  18. Dose determination in computed tomography

    International Nuclear Information System (INIS)

    Descamps, C.; Garrigo, E.; Venencia, D.; Gonzalez, M.; Germanier, A.

    2011-10-01

    In the last years the methodologies to determine the dose in computed tomography have been revised. In this work was realized a dosimetric study about the exploration protocols used for simulation of radiotherapy treatments. The methodology described in the Report No. 111 of the American Association of Medical Physiques on a computed tomograph of two cuts was applied. A cylindrical phantom of water was used with dimensions: 30 cm of diameter and 50 cm of longitude that simulates the absorption and dispersion conditions of a mature body of size average. The doses were determined with ionization chamber and thermoluminescent dosimetry. The results indicate that the dose information that provides the tomograph underestimates the dose between 32 and 35%.

  19. Gamma Radiation Doses In Sweden

    International Nuclear Information System (INIS)

    Almgren, Sara; Isaksson, Mats; Barregaard, Lars

    2008-01-01

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

  20. Dose assessment at Bikini Atoll

    International Nuclear Information System (INIS)

    Robison, W.L.; Phillips, W.A.; Colsher, C.S.

    1977-01-01

    Bikini Atoll is one of two sites in the northern Marshall Islands that was used by the United States as testing grounds for the nuclear weapons program from 1946 to 1958. In 1969 a general cleanup began at Bikini Atoll. Subsistence crops, coconut and Pandanus fruit, were planted on Bikini and Eneu Islands, and housing was constructed on Bikini Island. A second phase of housing was planned for the interior of Bikini Island. Preliminary data indicated that external gamma doses in the interior of the island might be higher than in other parts of the island. Therefore, to select a second site for housing on the island with minimum external exposure, a survey of Bikini Atoll was conducted in June 1975. External gamma measurements were made on Bikini and Eneu Islands, and soil and vegetations samples collected to evaluate the potential doses via terrestrial food chains and inhalation. Estimates of potential dose via the marine food chain were based upon data collected on previous trips to the atoll. The terrestrial pathway contributes the greater percentage, external gamma exposure contributes the next highest, and inhalation and marine pathways contribute minor fractions of the total whole body and bone marrow doses. The radionuclides contributing the major fraction of the dose are 90 Sr and 137 Cs. All living patterns involving Bikini Island exceed federal guidelines for 30-yr population doses. The Eneu Island living pattern leads to doses that are slightly less than federal guidelines. All patterns evaluated for Bikini Atoll lead to higher doses than those on the southern islands at Enewetak Atoll

  1. Dose Distribution of Gamma Irradiators

    International Nuclear Information System (INIS)

    Park, Seung Woo; Shin, Sang Hun; Son, Ki Hong; Lee, Chang Yeol; Kim, Kum Bae; Jung, Hai Jo; Ji, Young Hoon

    2010-01-01

    Gamma irradiator using Cs-137 have been widely utilized to the irradiation of cell, blood, and animal, and the dose measurement and education. The Gamma cell 3000 Elan (Nordion International, Kanata, Ontario, Canada) irradiator was installed in 2003 with Cs-137 and dose rate of 3.2 Gy/min. And the BioBeam 8000 (Gamma-Service Medical GmbH, Leipzig, Germany) irradiator was installed in 2008 with Cs-137 and dose rate of 3.5 Gy/min. Our purpose was to evaluate the practical dosimetric problems associated with inhomogeneous dose distribution within the irradiated volume in open air state using glass dosimeter and Gafchromic EBT film dosimeter for routine Gamma irradiator dosimetry applications at the KIRAMS and the measurements were compared with each other. In addition, an user guideline for useful utilization of the device based on practical dosimetry will be prepared. The measurement results of uniformity of delivered dose within the device showed variation more than 14% between middle point and the lowest position at central axis. Therefore, to maintain dose variation within 10%, the criteria of useful dose distribution, for research radiation effects, the irradiated specimen located at central axis of the container should be placed within 30 mm from top and bottom surface, respectively. In addition, for measurements using the film, the variations of dose distribution were more then 50% for the case of less than 10 second irradiation, mostly within 20% for the case of more than 20 second irradiation, respectively. Therefore, the irradiation experiments using the BioBeam 8000 irradiator are recommended to be used for specimen required at least more than 20 second irradiation time.

  2. Personnel external dose monitoring system

    International Nuclear Information System (INIS)

    Zhao Hengyuan

    1989-01-01

    The status and trend of personnel external dose monitoring system are introduced briefly. Their characteristics, functions and TLD bedges of some commercially available automatic TLD system, including UD-710A (Matsushita, Japan), Harshaw-2271, 2276 (Harshaw, USA), Harshaw-8000 (Harshaw/Filtrol), Studsvik-1313 (Sweden) and Pitman-800 (UK) were depicted in detail. Finally, personnel dose management and record keeping system were presented and two examples were given

  3. Occupational doses in pediatric barium meal procedures

    International Nuclear Information System (INIS)

    Filipov, D.; Schelin, H.R.; Denyak, V.; Legnani, A.; Ledesma, J.A.; Paschuk, S.A.; Sauzen, J.; Yagui, A.; Hoff, G.; Khoury, H.J.

    2015-01-01

    Ionizing radiation has become an indispensable tool when it comes to diagnosis and therapy. However, its use should happen in a rational manner, taking into account the risks to which the staff is being exposed. Barium meal (BM), or upper gastrointestinal (GI) studies, using fluoroscopy, are widely used for gastroesophageal reflux disease diagnostic in children and professionals are required to stay inside the examination room to position and immobilize pediatric patients during the procedure. Therefore, it is very important that proffessionals strictly follow the technical standards of radiation protection. According to the ICRP and the NCRP recommendations, the annual limit equivalent doses for eyes, thyroid and hands are, espectively, 20 mSv, 150 mSv and 500 mSv. Based on those data, the aim of the current study is to estimate the annual equivalent dose for eyes, thyroid and hands of professionals who perform BM procedures in children. This was done using properly package LiF:Mg,Cu,P thermoluminescent dosimeters in 37 procedures; 2 pairs were positioned near each staff´s eye, 2 pairs on each professional´s neck (on and under the lead protector) and 2 pairs on both staff´s hands. The range of the estimative annual equivalent doses, for eyes, thyroid and hands, are, respectively: 14 – 36 mSv, 7 – 22 mSv and 14 – 58 mSv. Only the closest staff to the patient exceeded the annual equivalent doses in the eyes (around 80% higher than the limit set by ICRP). However, the results from this study, for hands and thyroid, compared to similar studies, show higher values. Therefore, the optimization implementation is necessary, so that the radiation levels can be reduced. (authors)

  4. The dose makes the medicine.

    Science.gov (United States)

    Stumpf, Walter E

    2006-06-01

    Dose and time considerations in the development and use of a drug are important for assessing actions and side effects, as well as predictions of safety and toxicity. This article deals with epistemological aspects of dose selection by probing into the linguistic and cultural roots for the measure of medicine mediated by the medical doctor. Because toxicity is related to dose, historic and recent views suggest that less can be more. At low, medium and high dose levels, effects can differ not only quantitatively but also qualitatively. Dose-related target activation and recognition of enantiodromic thresholds between beneficial and toxic effects require elucidation of underlying events. Such studies, including hormesis and microdosing, call for extended ADME procedures with high-resolution methods in addition to the current low-resolution approaches. Improved information of drug logistics and target pharmacokinetics enables effective drug selection, dose determination and prediction. It also allows considerations of systems biology [i.e. integral (gestalt) pharmacology] exemplified by the drug homunculus, as in the case of vitamin D, that might lead to new paradigms and drug design.

  5. Weldon Spring historical dose estimate

    Energy Technology Data Exchange (ETDEWEB)

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

    1986-07-01

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

  6. Weldon Spring historical dose estimate

    International Nuclear Information System (INIS)

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

    1986-07-01

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

  7. Risk after low radiation doses

    International Nuclear Information System (INIS)

    Streffer, C.

    1989-01-01

    The high-level data measured in radiation doses need to be extrapolated to lower dose ranges in order to be able to state the risk of leukaemia and cancer in low radiation doses. The assumption is that there is no threshold dose although there has been no scientific verification for this yet. Conceptual considerations concerning the radiation action mechanisms suggest that a threshold dose does not exist. The assumption is that leukaemia and cancer are induced by the fact that individual transformed and malignant cells possess a certain though low potential to cause a malignant disease (leukaemia or cancer). It is assumed that radiation exposure produces damage to the genetic material of the cell which results in a malignant transformation. The number of these events is greatly reduced by a highly effective repair mechanism. However, these repair processes at the DNA are not complete or may even result in a misrepair; even low radiation doses (less than 10 mSv, 1 rem) apparently may trigger such cellular effects (transformation). (orig./HSCH) [de

  8. Technical basis for dose reconstruction

    International Nuclear Information System (INIS)

    Anspaugh, L.R.

    1996-01-01

    The purpose of this paper is to consider two general topics: technical considerations of why dose-reconstruction studies should or should not be performed and methods of dose reconstruction. The first topic is of general and growing interest as the number of dose-reconstruction studies increases, and one asks the question whether it is necessary to perform a dose reconstruction for virtually every site at which, for example, the Department of Energy (DOE) has operated a nuclear-related facility. And there is the broader question of how one might logically draw the line at performing or not performing dose-reconstruction (radiological and chemical) studies for virtually every industrial complex in the entire country. The second question is also of general interest. There is no single correct way to perform a dose-reconstruction study, and it is important not to follow blindly a single method to the point that cheaper, faster, more accurate, and more transparent methods might not be developed and applied

  9. Determination of the radiation dose to the body due to external radiation

    International Nuclear Information System (INIS)

    Drexler, G.; Eckerl, H.

    1985-01-01

    Section 63 of the Radiation Protection Ordinance defines the basic requirement, determination of radiation dose to the body. The determination of dose equivalents for the body is the basic step in practical monitoring of dose equivalents or dose limits with regard to individuals or population groups, both for constant or varying conditions of exposure. The main field of monitoring activities is the protection of persons occupationally exposed to ionizing radiation. Conversion factors between body doses and radiation quantities are explained. (DG) [de

  10. Biological dose estimation in a radiation accident involving low-dose ...

    African Journals Online (AJOL)

    Blood specimens were collected from 8 people 18 days after they had been accidentally exposed to a 947,2 GBq iridium192 source during industrial application. The equivalent whole-body dose received at day 0 was estimated using a model based on quantitative and qualitative chromosome aberration analysis in ...

  11. Dose assessments for SFR 1

    International Nuclear Information System (INIS)

    Bergstroem, Ulla; Avila, Rodolfo; Ekstroem, Per-Anders; Cruz, Idalmis de la

    2008-05-01

    Following a review by the Swedish regulatory authorities of the safety analysis of the SFR 1 disposal facility for low and intermediate level waste, SKB has prepared an updated safety analysis, SAR-08. This report presents estimations of annual doses to the most exposed groups from potential radionuclide releases from the SFR 1 repository for a number of calculation cases, selected using a systematic approach for identifying relevant scenarios for the safety analysis. The dose estimates can be used for demonstrating that the long term safety of the repository is in compliance with the regulatory requirements. In particular, the mean values of the annual doses can be used to estimate the expected risks to the most exposed individuals, which can then be compared with the regulatory risk criteria for human health. The conversion from doses to risks is performed in the main report. For one scenario however, where the effects of an earthquake taking place close to the repository are analysed, risk calculations are presented in this report. In addition, prediction of concentrations of radionuclides in environmental media, such as water and soil, are compared with concentration limits suggested by the Erica-project as a base for estimating potential effects on the environment. The assessment of the impact on non-human biota showed that the potential impact is negligible. Committed collective dose for an integration period of 10,000 years for releases occurring during the first thousand years after closure are also calculated. The collective dose commitment was estimated to be 8 manSv. The dose calculations were carried out for a period of 100,000 years, which was sufficient to observe peak doses in all scenarios considered. Releases to the landscape and to a well were considered. The peaks of the mean annual doses from releases to the landscape are associated with C-14 releases to a future lake around year 5,000 AD. In the case of releases to a well, the peak annual doses

  12. Dose assessments for SFR 1

    Energy Technology Data Exchange (ETDEWEB)

    Bergstroem, Ulla (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Avila, Rodolfo; Ekstroem, Per-Anders; Cruz, Idalmis de la (Facilia AB, Bromma (Sweden))

    2008-06-15

    Following a review by the Swedish regulatory authorities of the safety analysis of the SFR 1 disposal facility for low and intermediate level waste, SKB has prepared an updated safety analysis, SAR-08. This report presents estimations of annual doses to the most exposed groups from potential radionuclide releases from the SFR 1 repository for a number of calculation cases, selected using a systematic approach for identifying relevant scenarios for the safety analysis. The dose estimates can be used for demonstrating that the long term safety of the repository is in compliance with the regulatory requirements. In particular, the mean values of the annual doses can be used to estimate the expected risks to the most exposed individuals, which can then be compared with the regulatory risk criteria for human health. The conversion from doses to risks is performed in the main report. For one scenario however, where the effects of an earthquake taking place close to the repository are analysed, risk calculations are presented in this report. In addition, prediction of concentrations of radionuclides in environmental media, such as water and soil, are compared with concentration limits suggested by the Erica-project as a base for estimating potential effects on the environment. The assessment of the impact on non-human biota showed that the potential impact is negligible. Committed collective dose for an integration period of 10,000 years for releases occurring during the first thousand years after closure are also calculated. The collective dose commitment was estimated to be 8 manSv. The dose calculations were carried out for a period of 100,000 years, which was sufficient to observe peak doses in all scenarios considered. Releases to the landscape and to a well were considered. The peaks of the mean annual doses from releases to the landscape are associated with C-14 releases to a future lake around year 5,000 AD. In the case of releases to a well, the peak annual doses

  13. Exposure doses to angiographers during interventional angiography

    International Nuclear Information System (INIS)

    Fukutomi, Yukimi; Yasuhara, Yoshifumi; Sugata, Shigenori; Fujii, Takashi; Kawakami, Toshiaki; Ikezoe, Junpei

    1997-01-01

    We report the exposure doses to angiographers during interventional angiography and the protective efficacy of protective aprons against X-rays in this study. The first (main) angiographer was exposed to the maximum dose of 1 μSv/min at the left chest area and lower abdominal area inside the protective apron. The second (assistant) angiographer was exposed to the maximum dose of 2 μSv/min at the left chest area and 1 μSv/min at the lower abdominal area. X-ray transmission ratio of the protective apron was 4.9 percent or less for UL25L, O percent for 0.35 mmPb and 4.3 percent or less for 0.5 mmPb. These results were lower than the dose equivalent limit based on the laws and ordinances. The protection capacities of these protective aprons proved to be sufficient. The exposure dose at the left extremity area outside the protective apron, however, was 24 times higher than at the left chest area inside. The data showed that it was not protected from scattered X-rays outside the protective apron. It is imperative to consider secondary protective material for the area outside the protective apron. Considering the risk of radiation, we need to better control exposure to angiographers. (author)

  14. Determination of the dose equivalent Hp(0.07) in hands of occupationally exposed personnel in the practice of proton emission tomography (PET/CT); Determinacion de la dosis equivalente Hp(0.07) en manos de trabajadores ocupacionalmente expuestos en la practica de Tomografia por Emision de Positrones (PET/CT)

    Energy Technology Data Exchange (ETDEWEB)

    Lea, D. [Servicio de Radiofisica Sanitaria, Unidad de Tecnologia Nuclear, Instituto Venezolano de Investigaciones Cientificas, Ministerio de Ciencia y Tecnologia, Km 11 Carretera Panamerican, Altos del Pipe, Caracas (Venezuela); Ruiz, N.; Esteves, L. [Centro Diagnostico Docente Las Mercedes, Calle Paris cruce con calle Caroni, Edif. CDD, Las Mercedes, Caracas (Venezuela)]. e-mail: dlea@ivic.ve

    2006-07-01

    In Venezuela recently it was implanted the Positron Emission Tomography technique (PET) with the perspective of implanting it at national level. Even when in our country practices it of nuclear medicine it exists from early of 70, there is not experience in the determination of the occupational doses by exposure to the external radiation in hands. By this reason, a concern exists in the workers of the centers of nuclear medicine where it is practiced the Positron Emission Tomography technique. In absence of the TLD dosimetry to measure dose in hands in our country, measurements of the dose equivalent of the workers of the PET national reference center were made, using a detector of hands type diode. It was determined the dose in hands in terms of dose equivalent Hp(0.07) in two work positions, that is: the corresponding to the transfer of the receiving vial of ({sup 18}F) FDG to the shield, quality control and uni doses division. The second work position corresponds the person in charge of administering, via intravenous, the ({sup 18}F) FDG. In this work it realizes the dose equivalent in hands Hp(0.07) measures in each one of the work positions before described by daily production. The informed doses correspond to a total average produced activity of 20.4 GBq (550 mCi). The results of the measurements in terms of dose equivalent in hands Hp(0.07) correspond to 2.1 {+-} 20% mSv in the work position of division and 0.4 {+-} 10% mSv in the position of injection of the radioactive material. At short term this foreseen until 4 productions per week, what means an annual dose equivalent Hp(0.07) in hands of 400 mSv approximately, without taking into account abnormal situations as its are spills of the ({sup 18}F) FDG in the work place. This work is the starting point so that the regulatory authority settles down, in Venezuela, dose restrictions in the PET practices and implant, in the centers of nuclear medicine, an optimization politics of this practice in conformity

  15. 1997 N-Basin Administrative Control Level Dose Extension

    International Nuclear Information System (INIS)

    Nellesen, A.L.

    1997-04-01

    This document provides justification for extending the Administrative Control Level of 500 mrem per year to 1,000 mrem per year Total Effective Dose Equivalent for workers involved with N-Reactor Basin Deactivation in accordance with established procedures

  16. Radiation dose monitoring in the clinical routine

    Energy Technology Data Exchange (ETDEWEB)

    Guberina, Nika [UK Essen (Germany). Radiology

    2017-04-15

    Here we describe the first clinical experiences regarding the use of an automated radiation dose management software to monitor the radiation dose of patients during routine examinations. Many software solutions for monitoring radiation dose have emerged in the last decade. The continuous progress in radiological techniques, new scan features, scanner generations and protocols are the primary challenge for radiation dose monitoring software systems. To simulate valid dose calculations, radiation dose monitoring systems have to follow current trends and stay constantly up-to-date. The dose management software is connected to all devices at our institute and conducts automatic data acquisition and radiation dose calculation. The system incorporates 18 virtual phantoms based on the Cristy phantom family, estimating doses in newborns to adults. Dose calculation relies on a Monte Carlo simulation engine. Our first practical experiences demonstrate that the software is capable of dose estimation in the clinical routine. Its implementation and use have some limitations that can be overcome. The software is promising and allows assessment of radiation doses, like organ and effective doses according to ICRP 60 and ICRP 103, patient radiation dose history and cumulative radiation doses. Furthermore, we are able to determine local diagnostic reference doses. The radiation dose monitoring software systems can facilitate networking between hospitals and radiological departments, thus refining radiation doses and implementing reference doses at substantially lower levels.

  17. The choice of food consumption rates for radiation dose assessments

    International Nuclear Information System (INIS)

    Simmonds, J.R.; Webb, G.A.M.

    1981-01-01

    The practical problem in estimating radiation doses due to radioactive contamination of food is the choice of the appropriate food intakes. To ensure compliance or to compare with dose equivalent limits, higher than average intake rates appropriate to critical groups should be used. However for realistic estimates of health detriment in the whole exposed population, average intake rates are more appropriate. (U.K.)

  18. The dose dependency of the over-dispersion of quartz OSL single grain dose distributions

    DEFF Research Database (Denmark)

    Thomsen, Kristina Jørkov; Murray, Andrew S.; Jain, Mayank

    2012-01-01

    to have been well-bleached at deposition is maximised and thus the accuracy with which the equivalent dose can be determined is – at least in principle – improved. However, analysis of single grain dose distributions requires knowledge of the dispersion of the well-bleached part of the dose distribution....... This can be estimated by measurement of a suitable analogue, e.g. a well-bleached aeolian sample, but this requires such an analogue to be available, and in addition the assumptions that the sample is in fact a) well-bleached, and b) has a similar dose rate heterogeneity to the fossil deposit. Finally......, it is an implicit assumption in such analysis that any over-dispersion is not significantly dose dependent. In this study we have undertaken laboratory investigations of the dose dependency of over-dispersion using a well-bleached modern sample with an average measured dose of 36 ± 3 mGy. This sample was prepared...

  19. Radiological dose assessment for vault storage concepts

    Energy Technology Data Exchange (ETDEWEB)

    Richard, R.F.

    1997-02-25

    This radiological dose assessment presents neutron and photon dose rates in support of project W-460. Dose rates are provided for a single 3013 container, the ``infloor`` storage vault concept, and the ``cubicle`` storage vault concept.

  20. Patient and staff doses in interventional neuroradiology

    International Nuclear Information System (INIS)

    Bor, D.; Cekirge, S.; Tuerkay, T.; Turan, O.; Guelay, M.; Oenal, E.; Cil, B.

    2005-01-01

    Radiation doses for interventional examinations are generally high and therefore necessitate dose monitoring for patients and staff. Relating the staff dose to a patient dose index, such as dose-area product (DAP), could be quite useful for dose comparisons. In this study, DAP and skin doses of 57 patients, who underwent neuro-interventional examinations, were measured simultaneously with staff doses. Although skin doses were comparable with the literature data, higher DAP values of 215 and 188.6 Gy cm 2 were measured for the therapeutical cerebral and carotid examinations, respectively, owing to the use of biplane system and complexity of the procedure. Mean staff doses for eye, finger and thyroid were measured as 80.6, 77.6 and 28.8 μGy per procedure. The mean effective dose per procedure for the radiologists was 32 μSv. In order to allow better comparisons to be made, DAP normalised doses were also presented. (authors)

  1. Influence of dose calculation algorithms on the predicted dose distribution and NTCP values for NSCLC patients

    DEFF Research Database (Denmark)

    Nielsen, Tine B; Wieslander, Elinore; Fogliata, Antonella

    2011-01-01

    To investigate differences in calculated doses and normal tissue complication probability (NTCP) values between different dose algorithms.......To investigate differences in calculated doses and normal tissue complication probability (NTCP) values between different dose algorithms....

  2. Notes on the effect of dose uncertainty

    International Nuclear Information System (INIS)

    Morris, M.D.

    1987-01-01

    The apparent dose-response relationship between amount of exposure to acute radiation and level of mortality in humans is affected by uncertainties in the dose values. It is apparent that one of the greatest concerns regarding the human data from Hiroshima and Nagasaki is the unexpectedly shallow slope of the dose response curve. This may be partially explained by uncertainty in the dose estimates. Some potential effects of dose uncertainty on the apparent dose-response relationship are demonstrated

  3. [Indications for low-dose CT in the emergency setting].

    Science.gov (United States)

    Poletti, Pierre-Alexandre; Andereggen, Elisabeth; Rutschmann, Olivier; de Perrot, Thomas; Caviezel, Alessandro; Platon, Alexandra

    2009-08-19

    CT delivers a large dose of radiation, especially in abdominal imaging. Recently, a low-dose abdominal CT protocol (low-dose CT) has been set-up in our institution. "Low-dose CT" is almost equivalent to a single standard abdominal radiograph in term of dose of radiation (about one sixth of those delivered by a standard CT). "Low-dose CT" is now used routinely in our emergency service in two main indications: patients with a suspicion of renal colic and those with right lower quadrant pain. It is obtained without intravenous contrast media. Oral contrast is given to patients with suspicion of appendicitis. "Low-dose CT" is used in the frame of well defined clinical algorithms, and does only replace standard CT when it can reach a comparable diagnostic quality.

  4. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Finch, S. M.; McMakin, A. H.

    1991-09-01

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation dose that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into five technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (i.e., dose estimates). The Source Terms Task develops estimates of radioactive emissions from Hanford facilities since 1944. The Environmental Transport Task reconstructs the movements of radioactive particles from the areas of release to populations. The Environmental Monitoring Data Task assemblies, evaluates and reports historical environmental monitoring data. The Demographics, Agriculture and Food Habits Task develops the data needed to identify the populations that could have been affected by the releases. The Environmental Pathways and Dose Estimates Task used the information derived from the other Tasks to estimate the radiation doses individuals could have received from Hanford radiation. This document lists the progress on this project as of September 1991. 3 figs., 2 tabs.

  5. Effective dose estimation during conventional and CT urography

    Science.gov (United States)

    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.

  6. Individual monitoring of external exposure in terms of personal dose equivalent, H{sub p}(d); Dosimetria personale esterna in termini di equivalente di dose personale, H{sub p}(d). Atti. Giornata di studio, Bologna, 28 febbraio 2001

    Energy Technology Data Exchange (ETDEWEB)

    Fantuzzi, E. [ENEA, Div. Protezione dell' Uomo e degli Ecosistemi, Centro Ricerche Ezio Clementel, Bologna (Italy)

    2001-07-01

    The institute for Radiation Protection of ENEA - Bologna has organised a one day-workshop on the subject: Individual monitoring of external exposure in terms of personal dose equivalent, H{sub p}(d). The aim of the workshop was the discussion of the new implications and modifications to be expected in the routine individual monitoring of external radiation, due to the issue of the Decree 241/00 (G.U. 31/8/2000) in charge since 01/01/2001. The decree set up in Italian law the standards contained in the European Directive EURATOM 96/29-Basic Standards for the Protection of Health of Workers and the General Public against Dangers arising from Ionizing Radiation. Among others, the definition of the operational quantities for external radiation for personal and environmental monitoring, H{sub p}(d) e H{sup *}(d) respectively as defined by ICRU (International Commission for Radiation Units and Measurements), requires to update the methods of measurements and calibration of the personal dosemeters and environmental monitors. This report collects the papers presented at the workshop dealing with the Personal Dose Equivalent, H{sub p}(d), the conversion coefficients, H{sub p}(d)/K{sub a} e H{sub p}(d)/{sub ,} obtained through Monte Carlo calculations published by ICRU and ICRP (International Commission for Radiation Protection), the new calibration procedures and the practical implication in the routine of individual monitoring in terms of H{sub p}(d). Eventually, in the last chapter, the answers to Frequently Asked Questions (FAQ) are briefly reported. [Italian] L'Istituto per la Radioprotezione dell'ENEA di Bologna ha organizzato una giornata di studio Dosimetria personale esterna in termini di equivalente di dose personale, H{sub p}(d). Lo scopo della giornata e' stato quello di discutere le novita' e le modifiche da apportare alle pratiche di monitoraggio dell'esposizione esterna alle radiazioni ionizzanti, a seguito dell'entrata in vigore

  7. Parameterization of solar flare dose

    International Nuclear Information System (INIS)

    Lamarche, A.H.; Poston, J.W.

    1996-01-01

    A critical aspect of missions to the moon or Mars will be the safety and health of the crew. Radiation in space is a hazard for astronauts, especially high-energy radiation following certain types of solar flares. A solar flare event can be very dangerous if astronauts are not adequately shielded because flares can deliver a very high dose in a short period of time. The goal of this research was to parameterize solar flare dose as a function of time to see if it was possible to predict solar flare occurrence, thus providing a warning time. This would allow astronauts to take corrective action and avoid receiving a dose greater than the recommended limit set by the National Council on Radiation Protection and Measurements (NCRP)

  8. Dose reconstruction using mobile phones

    International Nuclear Information System (INIS)

    Beerten, K.; Reekmans, F.; Schroeyers, W.; Lievens, L.; Vanhavere, F.

    2011-01-01

    Electronic components inside mobile phones are regarded as useful tools for accident and retrospective dosimetry using optically stimulated luminescence (OSL) and thermoluminescence. Components inside the devices with suitable properties for luminescence dosimetry include, amongst others, ceramic substrates in resistors, capacitors, transistors and antenna switches. Checking the performance of such devices in dosimetric experiments is a crucial step towards developing a reliable dosimetry system for emergency situations using personal belongings. Here, the results of dose assessment experiments using irradiated mobile phones are reported. It will be shown that simple regenerative dose estimates, derived from various types of components removed from different mobile phone models, are consistent with the given dose, after applying an average fading correction factor. (authors)

  9. Consultative exercise on dose assessments.

    Science.gov (United States)

    Bridges, B A; Parker, T; Simmonds, J R; Sumner, D

    2001-06-01

    A summary is given of a meeting held at Sussex University, UK, in October 2000, which allowed the exchange of ideas on methods of assessment of dose to the public arising from potential authorised radioactive discharges from nuclear sites in the UK. Representatives of groups with an interest in dose assessments were invited, and hence the meeting was called the Consultative Exercise on Dose Assessments (CEDA). Although initiated and funded by the Food Standards Agency, its organisation, and the writing of the report, were overseen by an independent Chairman and Steering Group. The report contains recommendations for improvement in co-ordination between different agencies involved in assessments, on method development and on the presentation of data on assessments. These have been prepared by the Steering Group, and will be taken forward by the Food Standards Agency and other agencies in the UK. The recommendations are included in this memorandum.

  10. Radiation Dose from Reentrant Electrons

    Science.gov (United States)

    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.

  11. Evaluation of various approaches for assessing dose indicators and patient organ doses resulting from radiotherapy cone-beam CT.

    Science.gov (United States)

    Rampado, Osvaldo; Giglioli, Francesca Romana; Rossetti, Veronica; Fiandra, Christian; Ragona, Riccardo; Ropolo, Roberto

    2016-05-01

    The aim of this study was to evaluate various approaches for assessing patient organ doses resulting from radiotherapy cone-beam CT (CBCT), by the use of thermoluminescent dosimeter (TLD) measurements in anthropomorphic phantoms, a Monte Carlo based dose calculation software, and different dose indicators as presently defined. Dose evaluations were performed on a CBCT Elekta XVI (Elekta, Crawley, UK) for different protocols and anatomical regions. The first part of the study focuses on using pcxmc software (pcxmc 2.0, STUK, Helsinki, Finland) for calculating organ doses, adapting the input parameters to simulate the exposure geometry, and beam dose distribution in an appropriate way. The calculated doses were compared to readouts of TLDs placed in an anthropomorphic Rando phantom. After this validation, the software was used for analyzing organ dose variability associated with patients' differences in size and gender. At the same time, various dose indicators were evaluated: kerma area product (KAP), cumulative air-kerma at the isocenter (Kair), cone-beam dose index, and central cumulative dose. The latter was evaluated in a single phantom and in a stack of three adjacent computed tomography dose index phantoms. Based on the different dose indicators, a set of coefficients was calculated to estimate organ doses for a range of patient morphologies, using their equivalent diameters. Maximum organ doses were about 1 mGy for head and neck and 25 mGy for chest and pelvis protocols. The differences between pcxmc and TLDs doses were generally below 10% for organs within the field of view and approximately 15% for organs at the boundaries of the radiation beam. When considering patient size and gender variability, differences in organ doses up to 40% were observed especially in the pelvic region; for the organs in the thorax, the maximum differences ranged between 20% and 30%. Phantom dose indexes provided better correlation with organ doses than Kair and KAP, with average

  12. Computing effective dose in cardiac CT

    Science.gov (United States)

    Huda, Walter; Tipnis, Sameer; Sterzik, Alexander; Schoepf, U. Joseph

    2010-07-01

    We present a method of estimating effective doses in cardiac CT that accounts for selected techniques (kV mAs-1), anatomical location of the scan and patient size. A CT dosimetry spreadsheet (ImPACT CT Patient Dosimetry Calculator) was used to estimate effective doses (E) using ICRP 103 weighting factors for a 70 kg patient undergoing cardiac CT examinations. Using dose length product (DLP) for the same scans, we obtained values of E/DLP for three CT scanners used in cardiac imaging from two vendors. E/DLP ratios were obtained as a function of the anatomical location in the chest and for x-ray tube voltages ranging from 80 to 140 kV. We also computed the ratio of the average absorbed dose in a water cylinder modeling a patient weighing W kg to the corresponding average absorbed dose in a water cylinder equivalent to a 70 kg patient. The average E/DLP for a 16 cm cardiac heart CT scan was 26 µSv (mGy cm)-1, which is about 70% higher than the current E/DLP values used for chest CT scans (i.e. 14-17 µSv (mGy cm)-1). Our cardiac E/DLP ratios are higher because the cardiac region is ~30% more radiosensitive than the chest, and use of the ICRP 103 tissue weighting factors increases cardiac CT effective doses by ~30%. Increasing the x-ray tube voltage from 80 to 140 kV increases the E/DLP conversion factor for cardiac CT by 17%. For the same incident radiation at 120 kV, doses in 45 kg adults were ~22% higher than those in 70 kg adults, whereas doses in 120 kg adults were ~28% lower. Accurate estimates of the patient effective dose in cardiac CT should use ICRP 103 tissue weighting factors, and account for a choice of scan techniques (kV mAs-1), exposed scan region, as well as patient size.

  13. The dose dependency of the over-dispersion of quartz OSL single grain dose distributions

    International Nuclear Information System (INIS)

    Thomsen, Kristina J.; Murray, Andrew; Jain, Mayank

    2012-01-01

    The use of single grain quartz OSL dating has become widespread over the past decade, particularly with application to samples likely to have been incompletely bleached before burial. By reducing the aliquot size to a single grain the probability of identifying the grain population most likely to have been well-bleached at deposition is maximised and thus the accuracy with which the equivalent dose can be determined is – at least in principle – improved. However, analysis of single grain dose distributions requires knowledge of the dispersion of the well-bleached part of the dose distribution. This can be estimated by measurement of a suitable analogue, e.g. a well-bleached aeolian sample, but this requires such an analogue to be available, and in addition the assumptions that the sample is in fact a) well-bleached, and b) has a similar dose rate heterogeneity to the fossil deposit. Finally, it is an implicit assumption in such analysis that any over-dispersion is not significantly dose dependent. In this study we have undertaken laboratory investigations of the dose dependency of over-dispersion using a well-bleached modern sample with an average measured dose of 36 ± 3 mGy. This sample was prepared as heated (750 °C for 1 h), bleached and untreated portions which were then given uniform gamma doses ranging from 100 mGy to 208 Gy. We show that for these samples the relative laboratory over-dispersion is not constant as a function of dose and that the over-dispersion is smaller in heated samples. We also show that the dim grains in the distributions have a greater over-dispersion than the bright grains, implying that insensitive samples will have greater values of over-dispersion than sensitive samples.

  14. The Effect of Low‑Dose Ketamine (Preemptive Dose) on ...

    African Journals Online (AJOL)

    Average dosage of diclofenac suppository and mean time for taking the first dosage of opioids have not statistical difference too (respectively; P = 0.76, P = 0.87). Average dose of pethidine was lesser than placebo statistically. It means, the case group did not take pethidine but this amount was 6 (20%) in the control one (P ...

  15. Do dose area product meter measurements reflect radiation doses ...

    African Journals Online (AJOL)

    Enrique

    the shoulder or thyroid guard, and on the hand.7. Radiologists receive larger radia- tion doses during abdominal studies than during cerebral studies, even though the .... body reading. The sitting position and the radiographer's physical build would also influence the reading. An ineffective thyroid guard, openings on.

  16. Stereotactic intracranial radiotherapy: Dose prescription

    International Nuclear Information System (INIS)

    Schlienger, M.; Lartigau, E.; Nataf, F.; Mornex, F.; Latorzeff, I.; Lisbona, A.; Mahe, M.

    2012-01-01

    The aim of this article was the study of the successive steps permitting the prescription of dose in stereotactic intracranial radiotherapy, which includes radiosurgery and fractionated stereotactic radiotherapy. The successive steps studied are: the choice of stereotactic intracranial radiotherapy among the therapeutic options, based on curative or palliative treatment intent, then the selection of lesions according to size/volume, pathological type and their number permitting the choice between radiosurgery or fractionated stereotactic radiotherapy, which have the same methodological basis. Clinical experience has determined the level of dose to treat the lesions and limit the irradiation of healthy adjacent tissues and organs at risk structures. The last step is the optimization of the different parameters to obtain a safe compromise between the lesion dose and healthy adjacent structures. Study of dose-volume histograms, coverage indices and 3D imaging permit the optimization of irradiation. For lesions close to or included in a critical area, the prescribed dose is planned using the inverse planing method. Implementation of the successively described steps is mandatory to insure the prescription of an optimized dose. The whole procedure is based on the delineation of the lesion and adjacent healthy tissues. There are sometimes difficulties to assess the delineation and the volume of the target, however improvement of local control rates and reduction of secondary effects are the proof that the totality of the successive procedures are progressively improved. In practice, stereotactic intracranial radiotherapy is a continually improved treatment method, which constantly benefits from improvements in the choice of indications, imaging, techniques of irradiation, planing/optimization methodology and irradiation technique and from data collected from prolonged follow-up. (authors)

  17. Benzodiazepine Initiation and Dose Escalation.

    Science.gov (United States)

    Skinner, Brian W; Johnston, Elizabeth V; Saum, Lindsay M

    2017-04-01

    Benzodiazepines (BZDs) place patients at a significant risk of falling. The current literature does not address if this risk is increased during initiation or dose escalations of BZDs. To determine if initiation or dose escalations of BZD regimens are associated with an increased risk of falls in hospitalized patients compared with patients maintained on their home dose or who had their dose decreased from baseline. This retrospective case-control study evaluated hospitalized patients aged 45 years or older who received a BZD. Patients who did not fall were collected in a 3:1 ratio to patients who fell. Comparisons were made between BZD regimens prior to admission and those 48 hours prior to the index date. The date of fall served as the index date for patients who fell, and the median time-to-fall served as the index date for all other patients. A total of 132 patients were included in the study (33 falls and 99 without a fall). No significant differences were noted in demographics, baseline mobility, or past medical history. Patients who fell had a significantly longer median length of stay (15 vs 10 days; P = 0.025). Additionally, patients who fell were more likely to have had their BZD regimen initiated or dose escalated compared with patients who did not fall (63.6% vs 41.4%; P = 0.043). The risk of falling while on a BZD is increased on initiation and dose escalations. Hospitals should ensure judicious use of BZDs in inpatients to reduce the risk of falls.

  18. X-ray security scanners for personnel and vehicle control: Dose quantities and dose values

    Energy Technology Data Exchange (ETDEWEB)

    Hupe, Oliver [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany)], E-mail: oliver.hupe@ptb.de; Ankerhold, Ulrike [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany)

    2007-08-15

    After the security related occurrences in the past few years, there is an increasing need for airport security and border controls. In the combat against terror and smuggling, X-rays are used for the screening of persons and vehicles. The exposure of humans to ionising radiation raises the question of justification. To solve this question, reliable and traceable dose values are needed. A research project of the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety was initiated. Its task is to measure the ambient dose equivalent, H*(10), and the personal dose equivalent, H{sub p}(10), for typical types of personnel and vehicle X-ray scanners, using the transmission and/or backscatter method. In the following, the measuring quantities which are to be used for these investigations will be discussed and the measuring instruments will be presented. Furthermore, the experimental set-up is described. For the personnel X-ray scanners investigated, the obtained dose values are in the range from 0.07 to 6 {mu}Sv. These values will be compared to the dose values of the natural environmental radiation and some exposures in the field of medicine.

  19. Specific gamma-ray dose constants for nuclides important to dosimetry and radiological assessment

    International Nuclear Information System (INIS)

    Unger, L.M.; Trubey, D.K.

    1982-05-01

    Tables of specific gamma-ray dose constants (the unshielded gamma-ray dose equivalent rate at 1 m from a point source) have been computed for approximately 500 nuclides important to dosimetry and radiological assessment. The half life, the mean attenuation coefficient, and thickness for a lead shield providing 95% dose equivalent attenuation are also listed

  20. Development of Real-Time Measurement of Effective Dose for High Dose Rate Neutron Fields

    International Nuclear Information System (INIS)

    Braby, L. A.; Reece, W. D.; Hsu, W. H.

    2003-01-01

    Studies of the effects of low doses of ionizing radiation require sources of radiation which are well characterized in terms of the dose and the quality of the radiation. One of the best measures of the quality of neutron irradiation is the dose mean lineal energy. At very low dose rates this can be determined by measuring individual energy deposition events, and calculating the dose mean of the event size. However, at the dose rates that are normally required for biology experiments, the individual events can not be separated by radiation detectors. However, the total energy deposited in a specified time interval can be measured. This total energy has a random variation which depends on the size of the individual events, so the dose mean lineal energy can be calculated from the variance of repeated measurements of the energy deposited in a fixed time. We have developed a specialized charge integration circuit for the measurement of the charge produced in a small ion chamber in typical neutron irradiation experiments. We have also developed 4.3 mm diameter ion chambers with both tissue equivalent and carbon walls for the purpose of measuring dose mean lineal energy due to all radiations and due to all radiations except neutrons, respectively. By adjusting the gas pressure in the ion chamber, it can be made to simulate tissue volumes from a few nanometers to a few millimeters in diameter. The charge is integrated for 0.1 seconds, and the resulting pulse height is recorded by a multi channel analyzer. The system has been used in a variety of photon and neutron radiation fields, and measured values of dose and dose mean lineal energy are consistent with values extrapolated from measurements made by other techniques at much lower dose rates. It is expected that this technique will prove to be much more reliable than extrapolations from measurements made at low dose rates because these low dose rate exposures generally do not accurately reproduce the attenuation and

  1. Natural radiation dose to Gammarus

    International Nuclear Information System (INIS)

    Paschoa, A.S.; Wrenn, M.E.; Eisenbud, M.

    1975-01-01

    The natural radiation dose rate to whole body and components of the Gammarus species (i.e., G. Tigrinus, G. Fasciatus and G. Daiberi) that occurs in the Hudson River is evaluated and the results compared with the upper limits of dose rates from man made sources to the whole body of the organisms. Methods were developed to study the distribution of alpha emitters from 226 Ra plus daughter products in Gammarus using autoradiographic techniques, taking into account the amount of radon that escapes from the organisms. This methodology may be adapted to study the distribution of alpha emitters in contaminated tissues of plants and animals

  2. Dose budget for exposure control

    International Nuclear Information System (INIS)

    Nair, P.S.

    1999-01-01

    Dose budget is an important management tool to effectively control the collective dose incurred in a nuclear facility. The budget represents a set of yardsticks or guidelines for use in controlling the internal activities, involving radiation exposure in the organisation. The management, through budget can evaluate the radiation protection performance at every level of the organisation where a number of independent functional groups work on routine and non-routine jobs. The discrepancy between the plan and the actual performance is high lighted through the budgets. The organisation may have to change the course of its operation in a particular area or revise its plan with due focus on appropriate protective measures. (author)

  3. Performance standard for dose Calibrator

    CERN Document Server

    Darmawati, S

    2002-01-01

    Dose calibrator is an instrument used in hospitals to determine the activity of radionuclide for nuclear medicine purposes. International Electrotechnical Commission (IEC) has published IEC 1303:1994 standard that can be used as guidance to test the performance of the instrument. This paper briefly describes content of the document,as well as explains the assessment that had been carried out to test the instrument accuracy in Indonesia through intercomparison measurement.Its is suggested that hospitals acquire a medical physicist to perform the test for its dose calibrator. The need for performance standard in the form of Indonesia Standard is also touched.

  4. Confectionery-based dose forms.

    Science.gov (United States)

    Tangso, Kristian J; Ho, Quy Phuong; Boyd, Ben J

    2015-01-01

    Conventional dosage forms such as tablets, capsules and syrups are prescribed in the normal course of practice. However, concerns about patient preferences and market demands have given rise to the exploration of novel unconventional dosage forms. Among these, confectionery-based dose forms have strong potential to overcome compliance problems. This report will review the availability of these unconventional dose forms used in treating the oral cavity and for systemic drug delivery, with a focus on medicated chewing gums, medicated lollipops, and oral bioadhesive devices. The aim is to stimulate increased interest in the opportunities for innovative new products that are available to formulators in this field, particularly for atypical patient populations.

  5. Optimizing lithium dosing in hemodialysis

    DEFF Research Database (Denmark)

    Bjarnason, N H; Munkner, R; Kampmann, J P

    2006-01-01

    in which we developed an algorithm based on a 2-compartment distribution without elimination. The GFR estimate led to plasma concentrations 3-4 times lower than those anticipated. In contrast, the estimates based on V(d) and the algorithm derived from pharmacokinetic modeling led to comparable loading dose...... estimates. Furthermore, the maintenance dose estimated from the central compartment (V1) led to plasma concentrations within the therapeutic range. Thus, a regimen where 12.2 mmol lithium was given after each hemodialysis session resulted in stable between-dialysis plasma lithium concentrations...

  6. Committed effective doses at various times after intakes of radionuclides

    CERN Document Server

    Phipps, A W; Kendall, G M; Silk, T J; Stather, J W

    1991-01-01

    This report contains details of committed effective doses at nine times after intake from intakes by ingestion and inhalation of 1 mu 1 AMAD particles by adults. Data are given for various chemical forms of 359 nuclides. It complements NRPB-R245 which describes the changes which have taken place since the last NRPB compendium of dose per unit intake factors (dose coefficients) and gives summary tables. Information on committed equivalent doses to organs is given in NRPB-M288. The information given in these memoranda is also available as a microcomputer package - NRPB-SR245.

  7. Evaluation of shipping doses and compositions for vitrified waste

    International Nuclear Information System (INIS)

    Shapiro, A.

    1996-01-01

    Shipments of radioactive materials must adhere to dose limits specified in the Code of Federal Regulations. This paper discusses methods for evaluating shipping doses of vitrified waste. A methodology was developed for evaluating the change in vitrification composition required to maintain shipping dose rates within limits. The point kernel codes QAD and Microshield were used to evaluate dose equivalent rates from specified waste forms and radioactivity measurements. The Origen code was utilized to provide the gamma-ray activity as a function of time from isotopic activity measurements. This gamma-ray activity served as source input for QAD. Microshield developed its own source from the given isotopic activities

  8. Radiation doses from mammography in Australia

    International Nuclear Information System (INIS)

    Thomson, J.E.M.; Young, B.F.; Young, J.G.; Tingey, D.R.C.

    1991-05-01

    During 1989-90 the Australian Radiation Laboratory conducted a postal survey of at least 90% of the mammographic facilities in Australia. The primary aim of the survey was to measure the mean glandular dose (MGD) and the X-ray beam half value layer (HVL) for a typical mammograph. The MGD and HVL were measured with a specially designed tissue equivalent monitor. In all, 258 mammographic centres were surveyed. It was found that for centres using film-screen imaging, the average mean glandular dose was 1.83 mGy for centres using grids and 0.84 mGy for centres not using grids. In addition to the MGD and HVL, comprehensive statistical information was collected and data is presented on the types of equipment and techniques used, the number and age of patients and demographic distribution of centres. Results indicate that the use of a grid is the major factor determining dose and several other factors appear to have minor effects. In view of the distribution of MGD, it is recommended that the mean glandular dose per image, for a 5 cm compressed breast thickness, should not exceed 2.0 mGy when a grid is used and 1.0 mGy without a grid. 63 refs., 11 tabs., 15 figs

  9. Mathematically defined phantoms for organ dose calculation

    International Nuclear Information System (INIS)

    Saito, Kimiaki

    1998-01-01

    There are physical and mathematical phantoms which, for simulating the radiation reactions in the body, composed from more than one tissue equivalent material(s). This review concerns the latter one, particularly the human phantom, for its characteristics, actual models, examples of dose calculation and problems in future. The human phantom is classified into the formula phantom where sizes and properties of human organs/tissues are expressed by the combination of formula, and the voxel phantom where they are expressed by the combination of small cubes (voxel). The formula phantom usually uses quadratic equations for expressing the organ shape and was firstly developed as a MIRD (Medical Internal Radiation Dose Committee)-5 phantom. Based on the MIRD-5, many versions such as female, male and child phantoms have been developed. Voxel phantoms are rather new and are based on CT data of a person. Both phantoms require human numerical data: e.g., from reference man for formula phantom and actual precise CT data for voxel phantom. Dose calculation revealed that, for the low energy photon, doses are rather different between the two phantoms. Future problems involve the further examination on the size and properties of organs, improvement of expression of the phantoms, preparation of standard phantoms, modulation and simplification of the procedure for preparing the voxel phantom and an idea for automatic construction of the human phantom with appropriate parameters. (K.H.)

  10. Medical and occupational dose reduction in pediatric barium meal procedures

    Science.gov (United States)

    Filipov, D.; Schelin, H. R.; Denyak, V.; Paschuk, S. A.; Ledesma, J. A.; Legnani, A.; Bunick, A. P.; Sauzen, J.; Yagui, A.; Vosiak, P.

    2017-11-01

    Doses received in pediatric Barium Meal procedure can be rather high. It is possible to reduce dose values following the recommendations of the European Communities (EC) and the International Commission on Radiological Protection (ICRP). In the present work, the modifications of radiographic techniques made in a Brazilian hospital according to the EC and the ICRP recommendations and their influence on medical and occupational exposure are reported. The procedures of 49 patients before and 44 after the optimization were studied and air kerma-area product (PK,A) values and the effective doses were evaluated. The occupational equivalent doses were measured next to the eyes, under the thyroid shield and on each hand of both professionals who remained inside the examination room. The implemented modifications reduced by 70% and 60% the PK,A and the patient effective dose, respectively. The obtained dose values are lower than approximately 75% of the results from similar studies. The occupational annual equivalent doses for all studied organs became lower than the limits set by the ICRP. The equivalent doses in one examination were on average below than 75% of similar studies.

  11. Endoscopy dose examinations at the Sao Paulo University Hospital

    International Nuclear Information System (INIS)

    Aldred, M.A.; Siqueira P, W.; Fonseca F, A.M. da; Nucci, J.R.; Yoshimura, E. M.; Okuno, E.

    1996-01-01

    During some specific endoscopic examinations, radiographic and fluoroscopic images of patients are taken with the medical staff near to them. To evaluate the equivalent and effective doses in these occupational exposures, simulated examinations have been performed, using an anthropomorphic phantom in place of one of the members of the staff. Thermoluminescent dosimeters were attached in various positions of the phantom in order to determine some organ doses. From the comparison between the experimentally determined doses the International and the Brazilian recommended occupational dose limits, the maximum number of examinations that any member of the staff can perform, was calculated. If a protective apron is used, this number is limited by the high equivalent dose to the eye lens (average of 1.67 mSv/examination) of the staff's member. (authors). 3 refs., 4 tabs

  12. Estimation of effective dose equivalente from external irradiations

    International Nuclear Information System (INIS)

    Wakabayashi, T.

    1985-07-01

    A methodology for computing effective dose equivalent, derived from the computer code ALGAM: Monte Carlo Estimation of Internal Dose from Gamma-ray Sources in a Phantom Man, developed at Oak Ridge National Laboratory, is presented. The modified code was run for 12 different photon energy levels, from 0,010 Mev to 4.0 Mev, which provides computing the absorved dose, for these energy levels, in each one of the 97 organs of the original code. The code also was run for the principal energy levels used in the calibration of the dosimetric films. The results of the absorved doses per photon obtained for these levels of energy have been transformed in effective dose equivalents. (M.A.C.) [pt

  13. Evaluation of occupational radiation dose of extremities on hysterosalpingography

    International Nuclear Information System (INIS)

    Filipov, D.; Kotowski, S.T.A.

    2017-01-01

    In the Hysterosalpingography (HSG) exam there is always a professional present with their hands very close to the radiation field. Based on CNEN, individuals occupationally exposed to radiation have equivalent dose limit values for the extremities (500 mSv / year). The objective of the study was to verify the equivalent dose in the hand region of an IOE (Occupationally Exposed Individual) that performs the HSG test and to compare it with the CNEN limit and with similar studies. A humanoid phantom was used to simulate the patient and an ionization chamber, which was placed in the place commonly occupied by the professional. The equivalent hand dose result (∼ 30 mSv / year) equals 6% of the CNEN annual dose limit, but is close to most studies using fluoroscopes. Therefore, the optimization of radiological protection is necessary to reduce these results

  14. Dose reduction - the radiologist's view

    International Nuclear Information System (INIS)

    Russell, J.G.B.

    1984-01-01

    The magnitude of the exposure to ionising radiation dominates radiological practice in only three fields, i.e. foetal radiography, mammography and computed tomography. The balance between risk and benefit are briefly examined. The types of hazard considered are carcinogenesis, genetic injury and organogenesis. Ways of achieving a reduction of the dose to the patient are also briefly discussed. (U.K.)

  15. Peritoneal Dialysis Dose and Adequacy

    Science.gov (United States)

    ... done in the mid-afternoon to increase the amount of waste removed and to prevent excessive absorption of fluid. The dialysis solution used for the long daytime dwell may have a higher concentration ... amount, or dose, of dialysis. The peritoneal equilibration test— ...

  16. The cost of occupational dose

    International Nuclear Information System (INIS)

    Fleishman, A.B.; Clark, M.J.

    1980-01-01

    The optimization of radiological protection will routinely involve the balancing of public and occupational exposure, particularly within the nuclear fuel cycle. For example the reduction of public exposure from an effluent stream could lead to increases in occupational exposure from treatment, storage and disposal operations. A methodology is propased for the estimation of the cost of occupational exposure in the UK (Pound man-Sv -1 ) based on valuations of changes in risk. A variable value for the cost of the occupational man-Sv is obtained depending on per caput dose levels. The values at particular per caput dose levels are different for occupational workers and the general public, because of different demography and assumptions on risk perception and aversion. They are however approximately the same when the per caput doses are expressed as percentages of the dose limits for workers and the general public respectively. An example of the application of the derived cost of the occupational man-Sv to an optimisation problem is given. (author)

  17. Dose response relationship and Alara

    International Nuclear Information System (INIS)

    Hubert, P.

    1986-09-01

    In this paper, it will be shown how dose-response relationships allow to give quantitative figures for the detriment of irradiation. At this stage, the detriment is expressed directly as a certain number of health effects, whose valuation is not dealt with here. The present tools for quantifying, their weaknesses and their strenghts, and their scientific basis will be developed

  18. Comparison of Nordic dose models

    International Nuclear Information System (INIS)

    Thykier-Nielsen, S.

    1978-04-01

    A comparison is made between the models used in the four Nordic countries, Finland, Norway, Sweden and Denmark, for calculation of concentrations and doses from releases of radioactive material to the atmosphere. The comparison is limited to the near-zone models, i.e. the models for calculation of concentrations and doses within 50 km from the release point, and it comprises the following types of calculation: a. Concentrations of airborne material, b. External gamma doses from a plume, c. External gamma doses from radioactive material deposited on the ground. All models are based on the gaussian dispersion model (the gaussian plume model). Unit releases of specific isotopes under specific meteorological conditions are assumed. On the basis of the calculation results from the models, it is concluded that there are no essential differences. The difference between the calculation results only exceeds a factor of 3 in special cases. It thus lies within the known limits of uncertainty for the gaussian plume model. (author)

  19. Dose modeling in ultraviolet phototherapy

    International Nuclear Information System (INIS)

    Grimes, David Robert; Robbins, Chris; O'Hare, Neil John

    2010-01-01

    Purpose: Ultraviolet phototherapy is widely used in the treatment of numerous skin conditions. This treatment is well established and largely beneficial to patients on both physical and psychological levels; however, overexposure to ultraviolet radiation (UVR) can have detrimental effects, such as erythemal responses and ocular damage in addition to the potentially carcinogenic nature of UVR. For these reasons, it is essential to control and quantify the radiation dose incident upon the patient to ensure that it is both biologically effective and has the minimal possible impact on the surrounding unaffected tissue. Methods: To date, there has been little work on dose modeling, and the output of artificial UVR sources is an area where research has been recommended. This work characterizes these sources by formalizing an approach from first principles and experimentally examining this model. Results: An implementation of a line source model is found to give impressive accuracy and quantifies the output radiation well. Conclusions: This method could potentially serve as a basis for a full computational dose model for quantifying patient dose.

  20. Dose limits for ionising radiation

    International Nuclear Information System (INIS)

    Gifford, D.

    1989-01-01

    Dose limits for exposure to ionising radiation are assessed to see if they give sufficient protection both for the occupationally exposed and for the general public. It is concluded that current limits give a level of safety that satisfies the necessary criteria in the light of present knowledge and further reductions would be unlikely to improve standards of safety. (author)

  1. The relative biological effectiveness of out-of-field dose

    Science.gov (United States)

    Balderson, Michael; Koger, Brandon; Kirkby, Charles

    2016-01-01

    Purpose: using simulations and models derived from existing literature, this work investigates relative biological effectiveness (RBE) for out-of-field radiation and attempts to quantify the relative magnitudes of different contributing phenomena (spectral, bystander, and low dose hypersensitivity effects). Specific attention is paid to external beam radiotherapy treatments for prostate cancer. Materials and methods: using different biological models that account for spectral, bystander, and low dose hypersensitivity effects, the RBE was calculated for different points moving radially out from isocentre for a typical single arc VMAT prostate case. The RBE was found by taking the ratio of the equivalent dose with the physical dose. Equivalent doses were calculated by determining what physical dose would be necessary to produce the same overall biological effect as that predicted using the different biological models. Results: spectral effects changed the RBE out-of-field less than 2%, whereas response models incorporating low dose hypersensitivity and by