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Sample records for absorbed fraction internal irradiation

  1. An analytical model to calculate absorbed fractions for internal dosimetry with alpha, beta and gamma emitters

    Ernesto Amato

    2014-03-01

    Full Text Available We developed a general model for the calculation of absorbed fractions in ellipsoidal volumes of soft tissue uniformly filled with alpha, beta and gamma emitting radionuclides. The approach exploited Monte Carlo simulations with the Geant4 code to determine absorbed fractions in ellipsoids characterized by a wide range of dimensions and ellipticities, for monoenergetic emissions of each radiation type. The so-obtained absorbed fractions were put in an analytical relationship with the 'generalized radius', calculated as 3V/S, where V is the ellipsoid volume and S its surface. Radiation-specific parametric functions were obtained in order to calculate the absorbed fraction of a given radiation in a generic ellipsoidal volume. The dose from a generic radionuclide can be calculated through a process of summation and integration over the whole radionuclide emission spectrum, profitably implemented in an electronic spreadsheet. We compared the results of our analytical calculation approach with those obtained from the OLINDA/EXM computer software, finding a good agreement in a wide range of sphere radii, for the high-energy pure beta emitter 90Y, the commonly employed beta-gamma emitter 131I, and the pure alpha emitter 213Po. The generality of our approach makes it useful an easy to implement in clinical dosimetry calculations as well as in radiation safety estimations when doses from internal radionuclide uptake are to be taken into account.

  2. Calculation of absorbed dose of anchorage-dependent cells from internal beta-rays irradiation

    Objective: To elicit the formula of internal dosimetry in anchorage-dependent cells by beta-emitting radionuclides from uniformly distributed volume sources. Methods: By means of the definition of absorbed dose and the MIRD (Medical International Radiation Dose) scheme the formula of internal dosimetry was reasonably deduced. Firstly, studying the systems of suspension culture cells. Then, taking account of the speciality of the systems of the anchorage-dependent cells and the directions of irradiation, the absorbed dose of anchorage -dependent cells was calculated by the accumulated radioactivity, beta-ray energy, and the volume of the cultured systems. Results: The formula of internal dosimetry of suspension culture cells and anchorage-dependent cells were achieved. At the same time, the formula of internal dosimetry of suspension culture cells was compared with that of MIRD and was confirmed accurate. Conclusion: The formula of internal dosimetry is concise, reliable and accurate

  3. Specific absorbed fraction for Korean adult voxel phantom from internal photon source

    Absorbed fraction (AF) and specific absorbed fraction (SAF) are crucial values for the calculation of radionuclide S-values and consequently for internal dose estimates. The formalism of the Medical Internal Radiation Dose (MIRD) committee of the Society of Nuclear Medicine (SNM) has been utilised as a standard in the calculation of individual organ doses for biologically distributed radionuclides and for different types of radiation. Although those quantities are highly sensitive to individual anatomical difference, the SAF dataset calculated by Caucasian-based stylised phantoms have been applied to Korean population until now. This study was intended to calculate the SAFs by using realistic Korean voxel phantom and Monte Carlo transport technique for the first time and compare the results with those of the existing Caucasian-based data and the Korean stylised phantom published recently. The up-to-date realistic Korean voxel phantom, KTMAN-2, which was developed from computed tomography (CT) images of an average Korean adult male, was employed for Monte Carlo calculation using EGSnrc user-code, developed for the purpose of this study. The SAFs for 32 target organs and tissues from the photon source, uniformly deposited in a total of 37 source organs and tissues, were calculated from KTMAN-2. The results were compared with those for an adult phantom of Oak Ridge National Laboratory (ORNL) and Korean adult stylised phantom. Two major reasons of discrepancy were analysed: (1) racial difference between the Korean and the Caucasian and (2) anatomical difference between stylised and voxel phantoms. When the source organ was identical to the target organ, difference in SAF caused by the difference in target-organ mass between the Korean and the Caucasian phantoms was mainly observed. When the source and target organs were not identical, significant difference in SAF was observed which was mainly attributed to the difference in inter-organ distance and organ shape between

  4. Specific absorbed fraction for Korean adult voxel phantom from internal photon source.

    Lee, C; Park, S; Lee, J K

    2007-01-01

    Absorbed fraction (AF) and specific absorbed fraction (SAF) are crucial values for the calculation of radionuclide S-values and consequently for internal dose estimates. The formalism of the Medical Internal Radiation Dose (MIRD) committee of the Society of Nuclear Medicine (SNM) has been utilised as a standard in the calculation of individual organ doses for biologically distributed radionuclides and for different types of radiation. Although those quantities are highly sensitive to individual anatomical difference, the SAF dataset calculated by Caucasian-based stylised phantoms have been applied to Korean population until now. This study was intended to calculate the SAFs by using realistic Korean voxel phantom and Monte Carlo transport technique for the first time and compare the results with those of the existing Caucasian-based data and the Korean stylised phantom published recently. The up-to-date realistic Korean voxel phantom, KTMAN-2, which was developed from computed tomography (CT) images of an average Korean adult male, was employed for Monte Carlo calculation using EGSnrc user-code, developed for the purpose of this study. The SAFs for 32 target organs and tissues from the photon source, uniformly deposited in a total of 37 source organs and tissues, were calculated from KTMAN-2. The results were compared with those for an adult phantom of Oak Ridge National Laboratory (ORNL) and Korean adult stylised phantom. Two major reasons of discrepancy were analysed: (1) racial difference between the Korean and the Caucasian and (2) anatomical difference between stylised and voxel phantoms. When the source organ was identical to the target organ, difference in SAF caused by the difference in target-organ mass between the Korean and the Caucasian phantoms was mainly observed. When the source and target organs were not identical, significant difference in SAF was observed which was mainly attributed to the difference in inter-organ distance and organ shape between

  5. Specific absorbed fractions of energy at various ages from internal photon sources: 7, Adult male

    Specific absorbed fractions (PHI's) in various organs of the body (target organs) from sources of monoenergetic photons in various other organs (source organs) are tabulated. In this volume PHI-values are tabulated for an adult male (70-kg Reference Man). These PHI-values can be used in calculating the photon component of the dose-equivalent rate in a given target organ from a given radionuclide that is present in a given source organ. The International Commission on Radiological Protection recognizes that the endosteal, or bone surface, cells are the tissue at risk for bone cancer. We have applied the dosimetry methods developed for beta-emitting radionuclides deposited in bone to follow the transport of secondary electrons that were freed by photon interactions through the microscopic structure of the skeleton. With these methods we can estimate PHI in the endosteal cells and can better estimate PHI in the active marrow; the latter is overestimated with other methods at photon energies below 200 keV. 12 refs., 2 tabs

  6. Specific absorbed fractions of energy at various ages from internal photon sources: 6, Newborn

    Specific absorbed fraction (PHI's) in various organs of the body (target organs) from sources of monoenergetic photons in various other organs (source organs) are tabulated. In this volume PHI-values are tabulated for a newborn or 3.4-kg person. These PHI-values can be used in calculating the photon component of the dose-equivalent rate in a given target from a given radionuclide that is present in a given source organ. The International Commission on Radiological Protection recognizes that the endosteal, or bone surface, cells are the tissue at risk for bone cancer. We have applied the dosimetry methods that Spiers and co-workers developed for beta-emitting radionuclides deposited in bone to follow the transport of secondary electrons that were freed by photon interactions through the microscopic structure of the skeleton. With these methods we can estimate PHI in the endosteal cells and can better estimate PHI in the active marrow; the latter is overestimated with other methods at photon energies below 200 keV. 12 refs., 2 tabs

  7. Specific absorbed fractions of energy at various ages from internal photon sources: 1, Methods

    Specific absorbed fractions (PHI's) in various organs of the body (target organs) from sources of monoenergetic photons in various other organs (source organs) are tabulated. This volume outlines various methods used to compute the PHI-values and describes how the ''best'' estimates recommended by us are chosen. These PHI-values can be used in calculating the photon component of the dose-equivalent rate in a given target organ from a given radionuclide that is present in a given source organ. The International Commission on Radiological Protection recognizes that the endosteal, or bone surface, cells are the tissue at risk for bone cancer. We have applied the dosimetry methods that Spiers and co-workers developed for beta-emitting radionuclides deposited in bone to follow the transport of secondary electrons that were freed by photon interactions through the microscopic structure of the skeleton. With these methods we can estimate PHI in the endosteal cells and can better estimate PHI in the active marrow; the latter is overestimated with the methods at photon energies below 200 keV. 41 refs., 25 figs., 23 tabs

  8. Internal photomechanical fracture of spatially limited absorbers irradiated by short laser pulses

    Paltauf, Guenther; Schmidt-Kloiber, Heinz

    1998-05-01

    A photomechanical damage mechanism in abosrbing regions or particles surrounded by a non-abosrbing medium after irradiation with a short laser pulse is investigated experimentally and theoretically. In tissue, such absorbers are for example melanosomes, blood vessels or tatoo pigments. It follows from theoretical considerations that the photoacoustic wave caused by irradiation of a spatially limited volume contains both compressive and tensile stress. Experiments were performed to test whether these tensile stresses cause cavitation in absorbers of spherical or cylindrical shape. High-speed video images of liquid spheres or gelatin cylinders (diameters 200 to 300 micrometer) suspended in oil showed that cavitation occurs at the center of the spheres or on the cylinder axis, respectively, shortly after irradiation with a light pulse (6 ns duration) from an optical parametric oscillator. The cavitation effect was observed at maximum temperatures below and above the boiling point and at ratios of the absorber size on the absorption length larger and smaller than one. The experimental findings are supported by theoretical calculations, from which strong tensile stresses are predicted in the interior of the absorbers, even if the values of acoustic impedance inside and outside the absorbing volume are equal. The reported effect is believed to cause damage to absorbers if the pulse duration is short enough to provide stress confinement, that is if the time an acoustic wave needs to cross the abosrbing region is longer than the pulse duration. For small absorbers such as melanosomes with a size of about 1 micrometer this requires a laser pulse duration in the picosecond regime.

  9. Specific absorbed fractions of energy at various ages from internal photon sources: 3, Five-year-old

    Specific absorbed fractions (PHI's) in various organs of the body (target organs) from sources of monoenergetic photons in various other organs (source organs) are tabulated. In this volume PHI-values are tabulated for a five-year-old or 19-kg person. These PHI-values can be used in calculating the photon component of the dose-equivalent rate in a given target organ from a given radionuclide that is present in a given source organ. The International Commission on Radiological Protection recognizes that the endosteal, or bone surface, cells are the tissue at risk for bone cancer. We have applied the dosimetry methods developed for beta-emitting radionuclides deposited in bone to follow the transport of secondary electrons that were freed by photon interactions through the microscopic structure of the skeleton. With these methods we can estimate PHI in the endosteal cells and can better estimate PHI in the active marrow; the latter is overestimated with other methods at photon energies below 200 keV. 12 refs., 2 tabs

  10. Specific absorbed fractions of energy at various ages from internal photon sources: 2, One-year-old

    Specific absorbed fractions (PHI's) in various organs of the body (targets organs) from sources of monoenergetic photons in various other organs (source organs) are tabulated. In this volume PHI-values are tabulated for a one-year old or 9.8-kg person. These PHI-values can be used in calculating the photon component of the dose-equivalent rate in a given target organ from a given radionuclide that is present in a given source organ. The International Commission of Radiological Protection recognizes that the endosteal or bone surface, cells are the tissue at risk for bone cancer. We have applied the dosimetry methods that Spiers and co-workers developed for beta-emitting radionuclides deposited in bone to follow the transport of secondary electrons that were freed by photon interactions through the microscopic structure of the skeleton. With these methods we can estimate PHI in the endosteal cells and can better estimate PHI in the active marrow; the latter is overestimated with other methods at photon energies below 200 keV. 12 refs., 2 tabs

  11. Specific absorbed fractions of energy at various ages from internal photon sources: 4, Ten-year-old

    Specific absorbed fractions (PHI's) in various organs of the body (target organs) from sources of monoenergetic photons in various other organs (source organs) are tabulated. In this volume PHI-values are tabulated for a ten-year-old or 32-kg person. These PHI-values can be used in calculating the photon component of the dose-equivalent rate in a given target organ from a given radionuclide that is present in a given source organ. The International Commission on Radiological Protection recognizes that the endosteal, or bone surface, cells are the tissue at risk for bone cancer. We have applied the dosimetry methods that Spiers and co-workers developed for beta-emitting radionuclides deposited in bone to follow the transport of secondary electrons that were freed by photon interactions through the microscopic structure of the skeleton. With these methods we can estimate PHI in the endosteal cells and can better estimate PHI in the active marrow; the latter is overestimated with other methods at photon energies below 200 keV. 12 refs., 2 tabs

  12. Absorbed fractions for electrons in ellipsoidal volumes

    Amato, E.; Lizio, D.; Baldari, S.

    2011-01-01

    We applied a Monte Carlo simulation in Geant4 in order to calculate the absorbed fractions for monoenergetic electrons in the energy interval between 10 keV and 2 MeV, uniformly distributed in ellipsoids made from soft tissue. For each volume, we simulated a spherical shape, four oblate and four prolate ellipsoids, and one scalene shape. For each energy and for every geometrical configuration, an analytical relationship between the absorbed fraction and a 'generalized radius' was found, and the dependence of the fit parameters from electron energy is discussed and fitted by proper parametric functions. With the proposed formulation, the absorbed fraction for electrons in the 10-2000 keV energy range can be calculated for all volumes and for every ellipsoidal shape of practical interest. This method can be directly applied to evaluation of the absorbed fraction from the radionuclide emission of monoenergetic electrons, such as Auger or conversion electrons. The average deposited energy per disintegration in the case of extended beta spectra can be evaluated through integration. Two examples of application to a pure beta emitter such as 90Y and to 131I, whose emission include monoenergetic and beta electrons plus gamma photons, are presented. This approach represent a generalization of our previous studies, allowing a comprehensive treatment of absorbed fractions from electron and photon sources uniformly distributed in ellipsoidal volumes of any ellipticity and volume, in the whole range of practical interest for internal dosimetry in nuclear medicine applications, as well as in radiological protection estimations of doses from an internal contamination.

  13. Computational modeling of the mathematical phantoms of the Brazilian woman to internal dosimetry calculations and for comparison of the absorbed fractions with specific reference women

    The theme of this work is the study of the concept of mathematical dummy - also called phantoms - used in internal dosimetry and radiation protection, from the perspective of computer simulations. In this work he developed the mathematical phantom of the Brazilian woman, to be used as the basis of calculations of Specific Absorbed Fractions (AEDs) in the body's organs and skeleton by virtue of goals with regarding the diagnosis or therapy in nuclear medicine. The phantom now developed is similar, in form, to Snyder phantom making it more realistic for the anthropomorphic conditions of Brazilian women. For so we used the Monte Carlo method of formalism, through computer modeling. As a contribution to the objectives of this study, it was developed and implemented the computer system cFAE - consultation Fraction Specific Absorbed, which makes it versatile for the user's query researcher

  14. Computational modeling of the mathematical dummy of the Brazilian woman for calculations of internal dosimetry and ends of comparison of the fractions absorbed specific with the woman reference

    Tools for dosimetric calculations are of the utmost importance for the basic principles of radiological protection, not only in nuclear medicine, but also in other scientific calculations. In this work a mathematical model of the Brazilian woman is developed in order to be used as a basis for calculations of Specific Absorbed Fractions (SAFs) in internal organs and in the skeleton, in accord with the objectives of diagnosis or therapy in nuclear medicine. The model developed here is similar in form to that of Snyder, but modified to be more relevant to the case of the Brazilian woman. To do this, the formalism of the Monte Carlo method was used by means of the ALGAM- 97R computational code. As a contribution to the objectives of this thesis, we developed the computational system cSAF - consultation for Specific Absorbed Fractions (cFAE from Portuguese acronym) - which furnishes several 'look-up' facilities for the research user. The dialogue interface with the operator was planned following current practices in the utilization of event-oriented languages. This interface permits the user to navigate by means of the reference models, choose the source organ, the energy desired, and receive an answer through an efficient and intuitive dialogue. The system furnishes, in addition to the data referring to the Brazilian woman, data referring to the model of Snyder and to the model of the Brazilian man. The system makes available not only individual data to the SAFs of the three models, but also a comparison among them. (author)

  15. Application of the ICRP/ICRU reference computational phantoms to internal dosimetry: calculation of specific absorbed fractions of energy for photons and electrons

    Hadid, L; Desbree, A; Franck, D; Blanchardon, E [IRSN, Institute for Radiological Protection and Nuclear Safety, Internal Dosimetry Department, IRSN/DRPH/SDI, BP 17, F-92262 Fontenay-aux-Roses Cedex (France); Schlattl, H; Zankl, M, E-mail: lama.hadid@irsn.f [Institute of Radiation Protection, Helmholtz Zentrum Muenchen-German Research Center for Environmental Health, Neuherberg (Germany)

    2010-07-07

    The emission of radiation from a contaminated body region is connected with the dose received by radiosensitive tissue through the specific absorbed fractions (SAFs) of emitted energy, which is therefore an essential quantity for internal dose assessment. A set of SAFs were calculated using the new adult reference computational phantoms, released by the International Commission on Radiological Protection (ICRP) together with the International Commission on Radiation Units and Measurements (ICRU). Part of these results has been recently published in ICRP Publication 110 (2009 Adult reference computational phantoms (Oxford: Elsevier)). In this paper, we mainly discuss the results and also present them in numeric form. The emission of monoenergetic photons and electrons with energies ranging from 10 keV to 10 MeV was simulated for three source organs: lungs, thyroid and liver. SAFs were calculated for four target regions in the body: lungs, colon wall, breasts and stomach wall. For quality assurance purposes, the simulations were performed simultaneously at the Helmholtz Zentrum Muenchen (HMGU, Germany) and at the Institute for Radiological Protection and Nuclear Safety (IRSN, France), using the Monte Carlo transport codes EGSnrc and MCNPX, respectively. The comparison of results shows overall agreement for photons and high-energy electrons with differences lower than 8%. Nevertheless, significant differences were found for electrons at lower energy for distant source/target organ pairs. Finally, the results for photons were compared to the SAF values derived using mathematical phantoms. Significant variations that can amount to 200% were found. The main reason for these differences is the change of geometry in the more realistic voxel body models. For electrons, no SAFs have been computed with the mathematical phantoms; instead, approximate formulae have been used by both the Medical Internal Radiation Dose committee (MIRD) and the ICRP due to the limitations imposed

  16. Application of the ICRP/ICRU reference computational phantoms to internal dosimetry: calculation of specific absorbed fractions of energy for photons and electrons

    Hadid, L.; Desbrée, A.; Schlattl, H.; Franck, D.; Blanchardon, E.; Zankl, M.

    2010-07-01

    The emission of radiation from a contaminated body region is connected with the dose received by radiosensitive tissue through the specific absorbed fractions (SAFs) of emitted energy, which is therefore an essential quantity for internal dose assessment. A set of SAFs were calculated using the new adult reference computational phantoms, released by the International Commission on Radiological Protection (ICRP) together with the International Commission on Radiation Units and Measurements (ICRU). Part of these results has been recently published in ICRP Publication 110 (2009 Adult reference computational phantoms (Oxford: Elsevier)). In this paper, we mainly discuss the results and also present them in numeric form. The emission of monoenergetic photons and electrons with energies ranging from 10 keV to 10 MeV was simulated for three source organs: lungs, thyroid and liver. SAFs were calculated for four target regions in the body: lungs, colon wall, breasts and stomach wall. For quality assurance purposes, the simulations were performed simultaneously at the Helmholtz Zentrum München (HMGU, Germany) and at the Institute for Radiological Protection and Nuclear Safety (IRSN, France), using the Monte Carlo transport codes EGSnrc and MCNPX, respectively. The comparison of results shows overall agreement for photons and high-energy electrons with differences lower than 8%. Nevertheless, significant differences were found for electrons at lower energy for distant source/target organ pairs. Finally, the results for photons were compared to the SAF values derived using mathematical phantoms. Significant variations that can amount to 200% were found. The main reason for these differences is the change of geometry in the more realistic voxel body models. For electrons, no SAFs have been computed with the mathematical phantoms; instead, approximate formulae have been used by both the Medical Internal Radiation Dose committee (MIRD) and the ICRP due to the limitations imposed

  17. Specific absorbed fractions of energy at various ages from internal photon sources: 5, Fifteen-year-old male and adult female

    Specific absorbed fractions (PHI's) in various organs of the body (target organs) from sources of monoenergetic photons in various other organs (source organs) are tabulated. In this volume PHI-values are tabulated for a fifteen-year-old male or an adult female (55 to 58 kg). These PHI-values can be used in calculating the photon component of the dose-equivalent rate in a given target organ from a given radionuclide that is present in a given source organ. The International Commission on Radiological Protection recognizes that the endosteal, or bone surface, cells are the tissue at risk for bone cancer. We have applied the dosimetry methods developed for beta-emitting radionuclides deposited in bone to follow the transport of secondary electrons that were freed by photon interactions through the microscopic structure of the skeleton. With these methods we can estimate PHI in the endosteal cells and can better estimate PHI in the active marrow; the latter is overestimated with other methods of Snyder et al. at photon energies below 200 keV. 12 refs., 2 tabs

  18. Absorbed fraction of electrons in human respiratory tract

    Absorbed fractions of electrons, defined as part of electron energy deposited in the target, were calculated for various combinations of source and targets in HRTM. In that propose source code for PENELOPE was developed while respirator tract was modeled according to ICRP66. Absorbed fractions were fitted with the function presented in the paper

  19. Self-absorption effects on electron absorbed fraction in the anterior nose

    The electron absorbed fraction in the anterior nose is estimated in the International Commission on Radiological Protection Publication 66 using EGS4 Code and a cylinder model. The electrons are assumed to come from point sources lining the inner surface of the nose. Although the radioactive source particles are carried in dust, self-absorption in the dust is ignored. Consequently, the absorbed fractions published in ICRP 66 cannot represent the correct energy deposition in the basal cell region. In this work we estimate the energy lost by the emitted electrons inside spherical dust particles, which vary in diameter from 1 μm to 100 μm. The absorbed fractions in the basal cell layer are then estimated using the modified electron energy spectrum. To illustrate these effects, modified absorbed fractions for a dust particle radius of 20 μm are compared to the absorbed fractions presented in ICRP 66. Significant differences are noted. (author)

  20. Comparison of internal doses calculated using the specific absorbed fractions of the average adult Japanese male phantom with those of the reference computational phantom-adult male of ICRP publication 110

    In order to study the effects of body sizes and masses of organs and tissues on internal dose assessment, the values corresponding to effective dose coefficients for intakes of radionuclides were calculated using the specific absorbed fractions (SAFs) of two phantoms: the average adult Japanese male phantom (JM-103) and the reference computational phantom-adult male (RCP-AM) of the International Commission on Radiological Protection. SAFs were evaluated using the phantoms and Monte Carlo radiation transport code MCNPX or were taken from published data. As a result of a comparison for 2894 cases of 923 radionuclides, the maximum discrepancy in the effective dose coefficients between the JM-103 and RCP-AM was about 40%. However, the discrepancies were smaller than 10% in 97% of all cases. (paper)

  1. Charged particle equilibrium effects on the electron absorbed fraction in the extra-thoracic airways

    Estimates of the dose to the extra thoracic airway (nasal vestibule) from inhaled beta-emitting radionuclides, obtained using the respiratory tract model presented in Publication 66 of the International Commission on Radiological Protection, frequently predict that the basal cells in this region are the most highly irradiated tissues of the body. The dose to the basal cells is averaged over a layer of tissue 10 μm thick located at a depth of 40 μm into the airway assuming that charged particle equilibrium exists. Since the target (basal cell layer) is very small and thin (10 cm2 area and 10 μm thickness), charged particle equilibrium does not exist. In this work the effect on the absorbed fraction of the lack of charged particle equilibrium is investigated. (authors)

  2. Taking into account absorbed doses in tooth enamel due to internal irradiation of human body by radioactive cesium isotopes at analysis EPR dosimetry data: Calculation by Monte-Carlo method

    Borysheva, N. [Medical Radiological Research Center, Korolyov str., 4, Obninsk 249020 (Russian Federation); Ivannikov, A. [Medical Radiological Research Center, Korolyov str., 4, Obninsk 249020 (Russian Federation)], E-mail: Ivannikov-Alexander@yandex.ru; Tikunov, D.; Orlenko, S.; Skvortsov, V.; Stepanenko, V. [Medical Radiological Research Center, Korolyov str., 4, Obninsk 249020 (Russian Federation); Hoshi, M. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553 (Japan)

    2007-07-15

    By Monte-Carlo simulation of ionizing particles transport, for a realistic mathematical phantom of a man supplemented by a dental region, absorbed doses in teeth enamel and whole body doses are calculated for cases of internal irradiation by {sup 137}Cs and {sup 134}Cs isotopes incorporated in the human body resulted from staying in radioactive contaminated territory. It is shown that dose in enamel constitutes (40{+-}4)% and (59{+-}6)% of whole body dose resulted from the decay of {sup 137}Cs and {sup 134}Cs isotopes, respectively. The results of calculations may be used for conversion of absorbed dose in enamel obtained by the tooth enamel EPR spectroscopy method to whole body dose for dosimetric investigation of population of territories contaminated by the radioactive cesium, which is specific for the Chernobyl accident.

  3. Specific absorbed fractions of electrons and photons for Rad-HUMAN phantom using Monte Carlo method

    Wang, Wen; Cheng, Meng-Yun; Long, Peng-Cheng; Hu, Li-Qin

    2015-07-01

    The specific absorbed fractions (SAF) for self- and cross-irradiation are effective tools for the internal dose estimation of inhalation and ingestion intakes of radionuclides. A set of SAFs of photons and electrons were calculated using the Rad-HUMAN phantom, which is a computational voxel phantom of a Chinese adult female that was created using the color photographic image of the Chinese Visible Human (CVH) data set by the FDS Team. The model can represent most Chinese adult female anatomical characteristics and can be taken as an individual phantom to investigate the difference of internal dose with Caucasians. In this study, the emission of mono-energetic photons and electrons of 10 keV to 4 MeV energy were calculated using the Monte Carlo particle transport calculation code MCNP. Results were compared with the values from ICRP reference and ORNL models. The results showed that SAF from the Rad-HUMAN have similar trends but are larger than those from the other two models. The differences were due to the racial and anatomical differences in organ mass and inter-organ distance. The SAFs based on the Rad-HUMAN phantom provide an accurate and reliable data for internal radiation dose calculations for Chinese females. Supported by Strategic Priority Research Program of Chinese Academy of Sciences (XDA03040000), National Natural Science Foundation of China (910266004, 11305205, 11305203) and National Special Program for ITER (2014GB112001)

  4. Specific absorbed fractions of electrons and photons for Rad-HUMAN phantom using Monte Carlo method

    WANG Wen; CHENG Meng-Yun; LONG Peng-Cheng; HU Li-Qin

    2015-01-01

    The specific absorbed fractions (SAF) for self-and cross-irradiation are effective tools for the internal dose estimation of inhalation and ingestion intakes of radionuclides.A set of SAFs of photons and electrons were calculated using the Rad-HUMAN phantom,which is a computational voxel phantom of a Chinese adult female that was created using the color photographic image of the Chinese Visible Human (CVH) data set by the FDS Team.The model can represent most Chinese adult female anatomical characteristics and can be taken as an individual phantom to investigate the difference of internal dose with Caucasians.In this study,the emission of mono-energetic photons and electrons of 10 keV to 4 MeV energy were calculated using the Monte Carlo particle transport calculation code MCNP.Results were compared with the values from ICRP reference and ORNL models.The results showed that SAF from the Rad-HUMAN have similar trends but are larger than those from the other two models.The differences were due to the racial and anatomical differences in organ mass and inter-organ distance.The SAFs based on the Rad-HUMAN phantom provide an accurate and reliable data for internal radiation dose calculations for Chinese females.

  5. Specific absorbed fraction in bone tissue and bone marrow resulting from photons distributed in the skeleton

    The computer code 'ALGAM: Monte Carlo Estimation of Internal Dose from Gamma -ray Sources in a Phanton Man' only provides for an average dose to bone marrow resulting from a photon source distributed in the human body. Since there is no realistic model for the separation of these doses in the present phantom, some modifications were performed in the ALGAM code in order to introduce an heterogeneous skeleton and through this new model it was possible to make the estimation of dose in bone marrow. The specific absorbed fraction resulting from running the new program for 12 monoenergetic photon sources distributed in three source organs - skeleton, red marrow and yellow marrow is presented. The results obtained show that for low photon energies, the old model overestimates the specific absorbed fraction in bone marrow up to a factor of 4; while in bone, it underestimates the specific absorbed fractions up to a factor of 1.6. (Author)

  6. Specific Absorbed Fractions of Electrons and Photons for Rad-HUMAN Phantom Using Monte Carlo Method

    Wang, Wen; Long, Peng-cheng; Hu, Li-qin

    2014-01-01

    The specific absorbed fractions (SAF) for self- and cross-irradiation are effective tools for the internal dose estimation of inhalation and ingestion intakes of radionuclides. A set of SAFs of photon and electron were calculated using the Rad-HUMAN phantom, a computational voxel phantom of Chinese adult female and created using the color photographic image of the Chinese Visible Human (CVH) data set. The model can represent most of Chinese adult female anatomical characteristics and can be taken as an individual phantom to investigate the difference of internal dose with Caucasians. In this study, the emission of mono-energetic photons and electrons of 10keV to 4MeV energy were calculated using the Monte Carlo particle transport calculation code MCNP. Results were compared with the values from ICRP reference and ORNL models. The results showed that SAF from Rad-HUMAN have the similar trends but larger than those from the other two models. The differences were due to the racial and anatomical differences in o...

  7. Specific absorbed fractions and S-factors for calculating absorbed dose to embryo and fetus

    The variation of specific absorbed fractions from maternal tissues to embryo/fetus is investigated for four different target masses and geometries. S-factors are calculated for selected radionuclides assumed to be distributed uniformly in fetal tissues represented by spheres from 1 mg to 4 kg. As an example, the dose to fetal tissues for iodine-131 and iron-59 is estimated based on human biokinetic data for various stages of pregnancy. 24 references, 4 tables

  8. A mathematical model of the nine-month pregnant woman for calculating specific absorbed fractions

    Watson, E.E.; Stabin, M.G.

    1986-01-01

    Existing models that allow calculation of internal doses from radionuclide intakes by both men and women are based on a mathematical model of Reference Man. No attempt has been made to allow for the changing geometric relationships that occur during pregnancy which would affect the doses to the mother's organs and to the fetus. As pregnancy progresses, many of the mother's abdominal organs are repositioned, and their shapes may be somewhat changed. Estimation of specific absorbed fractions requires that existing mathematical models be modified to accommodate these changes. Specific absorbed fractions for Reference Woman at three, six, and nine months of pregnancy should be sufficient for estimating the doses to the pregnant woman and the fetus. This report describes a model for the pregnant woman at nine months. An enlarged uterus was incorporated into a model for Reference Woman. Several abdominal organs as well as the exterior of the trunk were modified to accommodate the new uterus. This model will allow calculation of specific absorbed fractions for the fetus from photon emitters in maternal organs. Specific absorbed fractions for the repositioned maternal organs from other organs can also be calculated. 14 refs., 2 figs.

  9. A mathematical model of the nine-month pregnant woman for calculating specific absorbed fractions

    Existing models that allow calculation of internal doses from radionuclide intakes by both men and women are based on a mathematical model of Reference Man. No attempt has been made to allow for the changing geometric relationships that occur during pregnancy which would affect the doses to the mother's organs and to the fetus. As pregnancy progresses, many of the mother's abdominal organs are repositioned, and their shapes may be somewhat changed. Estimation of specific absorbed fractions requires that existing mathematical models be modified to accommodate these changes. Specific absorbed fractions for Reference Woman at three, six, and nine months of pregnancy should be sufficient for estimating the doses to the pregnant woman and the fetus. This report describes a model for the pregnant woman at nine months. An enlarged uterus was incorporated into a model for Reference Woman. Several abdominal organs as well as the exterior of the trunk were modified to accommodate the new uterus. This model will allow calculation of specific absorbed fractions for the fetus from photon emitters in maternal organs. Specific absorbed fractions for the repositioned maternal organs from other organs can also be calculated. 14 refs., 2 figs

  10. Absorbed dose estimation and prediction irradiation effects in tumor-bearing mice under radionuclide therapy

    Full text: As the sizes of mouse organ are comparable with the range of the high-energy beta particles emitted by the radionuclides commonly used in radionuclide therapy a significant amount of beta radiation emitted could be imparted to the adjacent tissues. The often assumption that beta particles are fully-absorbed at the emission site is not satisfied and cross-irradiation should be included into the dose estimation formulas. Keeping in mind that the radiation effects are correlated with the absorbed dose in the target the inclusion of cross-irradiation in the dose estimation must be evaluated. The MIRD's formulation was used to perform absorbed dose calculation in mice using absorbed fractions previously reported for 131I, 90Y and 177Lu. Two approaches were considered: a) cross irradiation when a fraction of beta particles emitted can escape from the organ source and, b) full self- irradiation when the beta particles are considered fully absorbed at the emission site. The formulation of linear-quadratic model was readapted to be used in the radionuclide therapy. Treatment with a single administration in mice was simulated and radiation effects on tumor, bone marrow and kidneys under the assumption of cross-irradiation were predicted. A biphasic repair kinetics was considered in the calculation of irradiation effects on kidneys. Typical published biokinetic data for radiopharmaceutical assayed in mice and radiobiological parameters were used in the calculations. The influence of cross irradiation condition was diverse for the tissues analyzed here. The absorbed dose values in kidneys calculated for both methods were no significantly different for low energies, but variations around to 40-50% (over or under-estimation) in absorbed dose were obtained for high energies. Approximately a 30% of the beta radiation emitted from bone will cross irradiates the bone marrow. For injected activities values higher than 10MBq (300μCi), as a single injection, the

  11. Specification of absorbed dose for reporting a therapeutic irradiation

    The problem of dose specification in external beam therapy with photons and electrons has been dealt with in ICRU Report 29 (1978). This problem arises from the fact that the absorbed dose distribution is usually not uniform in the target volume and that for the purpose of treatment reporting a nominal absorbed dose - which will be called target absorbed dose - has to be selected. When comparing the clinical results obtained between radiotherapy centres, the differences in the reported target absorbed doses which can be introduced by differences in the methods of dose specification often are much larger than the differences related to the dosimetric procedures themselves. This shows the importance of the problem. In this paper, some definitions of terms and concepts currently used in radiotherapy are first recalled: tumour volume, target volume, treatment volume, etc. These definitions have been proposed in ICRU Report 29 for photon and electron beams; they can be extended to any kind of irradiation. For external beam therapy with photons and electrons, the target absorbed dose is defined as the absorbed dose at selected point(s) (specification point(s)) having a meaningful relation to the target volume and/or the irradiation beams. Examples are discussed for typical cases. As far as interstitial and intracavitary therapy is concerned, the problem is more complex and no recommendations have so far been made by the ICRU Commission. A major difficulty arises from the sharp dose gradient as a function of the distance to the sources. The particular case of the treatment of cervix carcinoma is considered and some possible methods of specification are discussed: (1) the indication of the sources (in adequate units) and the duration of the application, (2) the absorbed doses at selected reference points (bladder, rectum, bony structures) and (3) the description of the tissue volume (height, width, thickness) encompassed by a given isodose surface (60Gy). (author)

  12. International Developments of Food Irradiation

    Loaharanu, P. [Head, Food Preservation Section, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Wagramerstr. 5, A-1400, Vienna (Austria)

    1997-12-31

    Food irradiation is increasingly accepted and applied in many countries in the past decade. Through its use, food losses and food-borne diseases can be reduced significantly, and wider trade in many food items can be facilitated. The past five decades have witnessed a positive evolution on food irradiation according to the following: 1940`s: discovery of principles of food irradiation; 1950`s: initiation of research in advanced countries; 1960`s: research and development were intensified in some advanced and developing countries; 1970`s: proof of wholesomeness of irradiated foods; 1980`s: establishment of national regulations; 1990`s: commercialization and international trade. (Author)

  13. International Developments of Food Irradiation

    Food irradiation is increasingly accepted and applied in many countries in the past decade. Through its use, food losses and food-borne diseases can be reduced significantly, and wider trade in many food items can be facilitated. The past five decades have witnessed a positive evolution on food irradiation according to the following: 1940's: discovery of principles of food irradiation; 1950's: initiation of research in advanced countries; 1960's: research and development were intensified in some advanced and developing countries; 1970's: proof of wholesomeness of irradiated foods; 1980's: establishment of national regulations; 1990's: commercialization and international trade. (Author)

  14. International status of food irradiation

    Recent international moves that are likely to result in an increasing acceptance of irradiated foods are reviewed. Particular attention is given to the activities of the FAO, WHO, Codex Alimentarius and to attitudes in the United States and the Asian-Pacific region. In 1979, the Codex Alimentarius Commission adopted a Recommended General Standard for Irradiated Food. A resume is given of a revised version of the standard that is presently under consideration. However, remaining barriers to trade in irradiated food are briefly discussed, such as legal and regulatory problems, labelling, public acceptance and economic viability

  15. Patient absorbed radiation doses estimation related to irradiation anatomy

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

  16. Irradiation performances of the Superphenix type absorber element

    Several aspects of irradiation behaviour of the SUPERPHENIX type absorber element are presented in this paper. A large programme of irradiation tests was performed in PHENIX to assess and to improve the absorber pin design whose main characteristics for the first load are a sodium bonded and vented pin with high density (96% TD) and highly enriched (up to 90 at % of boron 10) B4C pellets. We present and discuss the main post-irradiation results obtained by this program which concerns the behaviour of both B4C pellets (fragmentation, swelling, helium release, thermal conductivity evolution) and stainless steel clad (embrittlement by carburization, mechanical interaction). It appears that the residence time of the first load of SUPERPHENIX control rods is clearly limited by mechanical interaction between B4C and the clad, and particularly by relocating of small fragments of B4C at beginning of life of the first gap. The irradiation performed in PHENIX led to fix the residence time of the first load of control rods to 240 e.f.p.d. The analyses of the effects limiting the residence time have enabled us to propose an extension of this time by two measures. The first one is reduction of the capture rate in boron carbide. The measure was brought into operation by mean of lowering at 48 at % the boron 10 enrichment of the B4C pellets in the lower part of the pin. The second measure is preventing the fragment relocation by adoption of a thin stainless shroud enclosing the pellet stack. The efficiency of these measures was proved in several irradiation tests (ANTIMAG experiments) in PHENIX. A burn-up of 220 x 1020 capt/cm3 was achieved without any dimensional change of the pin diameter. The shroud failed but could nevertheless prevent any pellet cladding deformation. Thus, these results have enabled us to fix a residence time of 640 e.f.p.d. for the third load of the SUPERPHENIX control rods. The achievement in the future of lifetime up to 1000 e.f.p.d. will require the

  17. Neutron Absorbing Ability Variation in Neutron Absorbing Material Caused by the Neutron Irradiation in Spent Fuel Storage Facility

    In spent fuel storage facility like high density spent fuel storage racks and dry storage casks, spent fuels are stored with neutron absorbing materials installed as a part of those facilities, and they are used for absorbing neutrons emitted from spent fuels. Usually structural material with neutron absorbing material of racks and casks are located around spent fuels, so it is irradiated by neutrons for long time. Neutron absorbing ability could be changed by the variation of nuclide composition in neutron absorbing material caused by the irradiation of neutrons. So, neutron absorbing materials are continuously faced with spent fuels with boric acid solution or inert gas environment. Major nuclides in neutron absorbing material are Al27, C12, B11, B10 and they are changed to numerous other ones as radioactive decay or neutron absorption reaction. The B10 content in neutron absorbing material dominates the neutron absorbing ability, so, the variation of nuclide composition including the decrease of B10 content is the critical factor on neutron absorbing ability. In this study, neutron flux in spent fuel, the activation of neutron absorbing material and the variation of nuclide composition are calculated. And, the minimum neutron flux causing the decrease of B10 content is calculated in spent fuel storage facility. Finally, the variation of neutron multiplication factor is identified according to the one of B10 content in neutron absorbing material. The minimum neutron flux to impact the neutron absorbing ability is 1010 order, however, usual neutron flux from spent fuel is 108 order. Therefore, even though neutron absorbing material is irradiated for over 40 years, B10 content is little decreased, so, initial neutron absorbing ability could be kept continuously

  18. Specific absorbed fraction of X-ray in tissues from human organs

    Full text: X- rays are widely used in medical imaging and radiation therapy. The user of radioisotopes must have knowledge about how radiation interacts with matter, especially with the human body, because when photons enter the medium/body, they degrade their energy and build up in the medium, giving rise to secondary radiation. Calculations of the energy absorbed in a medium include not only the contribution of the uncollided photons from the source, but must also include the contributions from collided and secondary photons. In practice, this is done by multiplying the contribution of the uncollided photons by the energy absorption buildup factor. An accurate absorbed dose calculation needs specific absorbed fraction of energy. Geometric progression (GP) fitting method has been used to compute energy absorption build-up factor of Human organs such as brain, breast, eye lens, GI track, heart, kidney, liver, lung, lymph, ovary, pancreas, testis and skeleton-femur. The computed absorption build-up factor is used to estimate specific absorbed fraction of energy. The thickness of the medium up to 10mm and with penetration depth up to 40 mean free paths considered. The dependence of specific absorbed fraction of energy on incident photon energy, penetration and the thickness of the medium have also been studied. The specific absorbed fraction of energy increases up to the Epe and then decreases. Here Epe is the energy value at which the photo electric interaction coefficients matches with Compton interaction coefficients for a given value of effective atomic number (Zeff). The variation of specific absorbed fractions with energy is due to dominance of photoelectric absorption in the lower end and dominance of pair production in the higher photon energy region. In the lower energy end photoelectric absorption is dominant photon interaction process; hence specific absorbed fractions values minimum. As the energy of incident photon increases, Compton scattering overtakes

  19. Calculation of half-value thickness for aluminum absorbers by means of fractional calculus

    Highlights: • Inconsistency of half-value thickness for Al absorber is corrected by fractional calculus. • Experiments and calculations are performed for Cs-137, Tl-204 and Sr-90/Y-90 beta sources. • Theoretical values are calculated as equivalent with experimental data at same fractional order. • This fractional order is standard for Al absorber. - Abstract: Half-value thickness of aluminum absorbers has been investigated experimentally and theoretically. Cs-137, Tl-204 and Sr-90/Y-90 radio-isotopes were used as beta sources. Inconsistency between experimental measurements and standard theoretical calculations has been removed with the help of fractional calculus. The experimental and theoretical half-thickness values have been found equivalent for fractional derivative order ≈0.3

  20. An international intercomparison of absorbed dose measurements for radiation therapy

    Dose intercomparison on an international basis has become an important component of quality assurance measurement i.e. to check the performance of absorbed dose measurements in radiation therapy. The absorbed dose to water measurements for radiation therapy at the SSDL, MINT have been regularly compared through international intercomparison programmes organised by the IAEA Dosimetry Laboratory, Seibersdorf, Austria such as IAEA/WHO TLD postal dose quality audits and the Intercomparison of therapy level ionisation chamber calibration factors in terms of air kerma and absorbed dose to water calibration factors. The results of these intercomparison in terms of percentage deviations for Cobalt 60 gamma radiation and megavoltage x-ray from medical linear accelerators participated by the SSDL-MINT during the year 1985-2001 are within the acceptance limit. (Author)

  1. Paired-organ and other selected absorbed fraction for the Korean Reference Adult Male model

    The authors have developed a mathematical model for calculating internal radionuclide dosimetry for the Korean Reference Adult Male, and have also derived paired-organ and other selected inter-organ photon-specific absorbed fractions for this model. Each lung, kidney and adrenal gland was set as a separate source region even though each of them shares an identical physiological function with their complementary half. The thyroid gland was also set as a source region. Specific absorbed fractions (SAFs) were then derived by selecting 10 photon energies from 0.02 to 4.0 MeV inclusive. For this purpose the Monte Carlo methodology was used, and the derived SAF was compared with the resulting value of MIRD Pamphlet No. 5 and ORNL TM-8381, both of which were derived on the basis of the ICRP-23 reference man. The comparison showed that MIRD No. 5 and ORNL TM-8381 resulted in a higher absorbed fraction, but the phantom created on the basis of the Korean reference man led to a higher SAF. The weight of the organs of the phantom, and the size and location of the trunk seem to account for the differences. The energy-dependent differences in the SAFs are considered to be related to the distance between the source and target regions, the composition of the intervening tissues, and the photon energies and mean free paths. Also, as a result of deriving SAFs after setting each separate lung, kidney and adrenal gland as a source region, it was found that, although they are of the same physiological function, each individual organ serves as a source region on its own. Differences were noted in SAFs exerted on the source and target organs in accordance with the location of the organs, that is, whether they were located to the left or right of the source organs. The SAF derived in this study can be used for a more accurate internal radionuclide dosimetry for Koreans and other Orientals whose physiology, lifestyle and dietary habits are similar to those of Koreans. (authors)

  2. Blood compounds irradiation process: assessment of absorbed dose using Fricke and Thermoluminescent dosimetric systems

    The assessment of gamma absorbed doses in irradiation facilities allows the quality assurance and control of the irradiation process. The liability of dose measurements is assign to the metrological procedures adopted including the uncertainty evaluation. Fricke and TLD 800 dosimetric systems were used to measure absorbed dose in the blood compounds using the methodology presented in this paper. The measured absorbed doses were used for evaluating the effectiveness of the irradiation procedure and the gamma dose absorption inside the irradiation room of a gamma irradiation facility. The radiation eliminates the functional and proliferative capacities of donor T-lymphocytes, preventing Transfusion associated graft-versus-host disease (TA-GVHD), a possible complication of blood transfusions. The results show the applicability of such dosimetric systems in quality assurance programs, assessment of absorbed doses in blood compounds and dose uniformity assign to the blood compounds irradiation process by dose measurements in a range between 25 Gy and 100 Gy. (author)

  3. Influence of caffeine on fractionated irradiation in wheat and barley

    Fractionated irradiation is one of the important methods studying repair of radiation damage. Some authors reported that caffeine, a repair inhibitor, had no effects on fractionated irradiation in human cell, animal cell and Vicia faba. And they concluded that caffeine inhibited the repair of potentially lethal damage (PLD), but did not inhibit the repair of sub-lethal damage (SLD). In this study, the effect of caffeine on the repair of PLD and SLD were reexamined in wheat and barley systems. The germinating seeds of wheat of barley were pre-irradiation treated 3 h with 5 x 10-3 mol/L caffeine, then they were irradiated by single or fractionated X-ray doses. The results showed that after caffeine treatment the effect of fractionated irradiation was disappeared. In this case, caffeine not only inhibited the repair of PLD but also inhibited the repair SLD. In previous fracttionated radiation experiments, the repairs during interval were discussed in detail, but the repairs after whole irradiation were neglected. According to the resuls of this experiment and some early reported about fractionated irradiation, the repair efficiency during interval and the repair function after whole irradiation were discussed

  4. A mathematical model for the kidney and estimative of the specific absorbed fractions by Monte Carlo method

    Presently, the estimates of specific absorbed fractions in various organs of a heterogeneous phantom are based on Monte Carlo calculation for monoenergetic photons uniformly distributed in the organs of an adult phantom. But, it is known that the kidney and some other organs (for example the skeleton) do not retain the radionuclides in an uniform manner in its internal region. So, we developed a model for the kidney including the cortex, medulla and collecting region. This model was utilized to estimate the specific absorbed fractions, for monoenergetic photons or electrons, in various organs of a heterogeneous phantom, when sources were uniformly distributed in each region of the kidney. All results obtained in this work were compared with those using a homogeneous model for the kidney as presented in ORNL-5000. (Author)

  5. Computational modeling of the mathematical dummy of the Brazilian woman for calculations of internal dosimetry and ends of comparison of the fractions absorbed specific with the woman reference; Modelagem computacional do manequim matematico da mulher brasileira para calculos de dosimetria interna e para fins de comparacao das fracoes absorvidas especificas com a mulher referencia

    Ximenes, Edmir

    2006-07-01

    Tools for dosimetric calculations are of the utmost importance for the basic principles of radiological protection, not only in nuclear medicine, but also in other scientific calculations. In this work a mathematical model of the Brazilian woman is developed in order to be used as a basis for calculations of Specific Absorbed Fractions (SAFs) in internal organs and in the skeleton, in accord with the objectives of diagnosis or therapy in nuclear medicine. The model developed here is similar in form to that of Snyder, but modified to be more relevant to the case of the Brazilian woman. To do this, the formalism of the Monte Carlo method was used by means of the ALGAM- 97{sup R} computational code. As a contribution to the objectives of this thesis, we developed the computational system cSAF - consultation for Specific Absorbed Fractions (cFAE from Portuguese acronym) - which furnishes several 'look-up' facilities for the research user. The dialogue interface with the operator was planned following current practices in the utilization of event-oriented languages. This interface permits the user to navigate by means of the reference models, choose the source organ, the energy desired, and receive an answer through an efficient and intuitive dialogue. The system furnishes, in addition to the data referring to the Brazilian woman, data referring to the model of Snyder and to the model of the Brazilian man. The system makes available not only individual data to the SAFs of the three models, but also a comparison among them. (author)

  6. Serial histopathological changes in irradiated guinea pig lung receiving conventional fractionated and hyperfractionated irradiation

    The purpose of this study is to determine serial histopathological differences in guinea pig lungs receiving the same total dose as clinically used between conventional fractionated and hyperfractionated irradiation. The guinea pigs received 80 Gy in 40 daily fractions of 2 Gy each (conventional fractionation), 80 Gy in 80 fractions of 1 Gy each twice a day (hyperfractionation), 81 Gy in 27 daily fractions of 3 Gy each (conventional fractionation), or 81 Gy in 54 fractions of 1.5 Gy each twice a day (hyperfractionation). We evaluated the histopathological changes of irradiated guinea pig lungs at 1, 2, 3, 6, 9, and 12 months after irradiation. The guinea pig lungs that received 81 Gy in 27 daily fractions showed histopathological changes of inflammation including formation of lymph follicles after 6 months. The lungs which received 81 Gy in 54 fractions showed similar but slightly less pronounced changes than those that received 81 Gy in 27 daily fractions. The guinea pig lungs of other groups showed no histopathological changes during the observation period. In hyperfractionated irradiation the damage to the guinea pig lung is quantitatively less than that occurring as a result of conventional fractionated irradiation of the same total dose. (author)

  7. Dynamic dose-shaping by gravity-oriented absorbers for total lymph node irradiation

    Rotational therapy with gravity-oriented absorbers is proposed for better total lymph node irradiation (TLI). Two metal semicylinders are joined coaxially (face to face) to form a radiation absorber that is centrally suspended in the beam. During rotation this absorber is kept parallel to itself by gravity, like the riders of a Ferris wheel. The vertebrae remain continuously protected under the absorber's shadow. The circular full-dose region, achieved by ordinary rotation, is now transformed into a horse-shoe region embracing the spine anteriorly. The abdominal lymph nodes are thus irradiated while the spine and most of the normal tissue around the spine are protected. A similar technique is applied for the selective irradiation of the pelvic lymph nodes, which are confined in the two legs of an inverted V region

  8. Estimating Solar Irradiation Absorbed by Photovoltaic Panels with Low Concentration Located in Craiova, Romania

    Ionel L. Alboteanu

    2015-03-01

    Full Text Available Solar irradiation is one of the important parameters that should be taken into consideration for the design and utilization of a photovoltaic system. Usually, the input parameters of a photovoltaic system are solar irradiation, the ambient environment temperature and the wind speed, and as a consequence most photovoltaic systems are equipped with sensors for measuring these parameters. This paper presents several mathematical models for solar irradiation assessment. The starting point is represented by the mathematical model of extraterrestrial irradiation, and resulting finally in the model for solar irradiation, absorbed by a low concentration photovoltaic panel. These estimating models of solar irradiation have been particularized for the Craiova, Romania, and have been verified through numerical simulation. Regarding terrestrial solar irradiation, four mathematical models have been adopted, namely Adnot, Haurwitz, Kasten and Empirical (EIM. Of these, the most appropriate for the Craiova location were the models Adnot and Empirical. Consequently, for the calculation of the solar irradiation absorbed by the photovoltaic (PV panels with low concentration, these models have been taken into consideration. In this study, a comparative analysis was also carried out with respect to the solar irradiation absorbed by the PV panels without concentration and those with collectedness of the solar radiation. This analysis was based on the results of numerical simulation and experimental tests.

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

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

  10. Traversal of cells by radiation and absorbed fraction estimates for electrons and alpha particles

    Consideration of the pathlength which radiation traverses in a cell is central to algorithms for estimating energy deposition on a cellular level. Distinct pathlength distributions occur for radionuclides: (1) uniformly distributed in space about the cell (referred to as μ-randomness); (2) uniformly distributed on the surface of the cell (S-randomness); and (3) uniformly distributed within the cell volume (I-randomness). For a spherical cell of diameter d, the mean pathlengths are 2/3d, and 3/4d, respectively, for these distributions. Algorithms for simulating the path of radiation through a cell are presented and the absorbed fraction in the cell and its nucleus are tabulated for low energy electrons and alpha particles emitted on the surface of spherical cells. The algorithms and absorbed fraction data should be of interest to those concerned with the dosimetry of radionuclide-labeled monoclonal antibodies. 8 references, 3 figures, 2 tables

  11. Storage tank with internal neutron absorbers for fissile materials

    The advantages of the new storage tank design with internal neutron absorbers for fissile materials compared to the traditional slab tank design are as follows: The available volume of this vessel design has a value of more than 80%. The tank does not require neutron absorbers to be spaced between adjacent tanks as with the case with slab tanks. This results in a saving in cost and space. The tank is smaller in height and breadth and thus requires less room space for the same amount of storage capacity. Costs are reduced in manufacturing material and room space. The outer surface area of the tank is roughly 7 times smaller than the outer surface area of the slab tank and in less area for heat transfer in case of fire - improved safety. The tank manufacturing will require less welding points to be done and the type of welding required can be automated by machinery. The welding method required, is similar to the welding method that is used to weld the fuel rods for conventional HWR nuclear reactors and thus the technology is known, automated and proven. The tube bundle can be easily removed and more space is available inside the tank for inspection and maintenance of the vessel due to the circular geometry. The vessel design is similar to pressure vessel design which is a proven and well documented method.

  12. Electron beam dosimetry for a thin-layer absorber irradiated by 300-keV electrons

    Depth-dose distributions in thin-layer absorbers were measured for 300-keV electrons from a scanning-type irradiation system, the electrons having penetrated through a Ti-window and an air gap. Irradiations of stacks of cellulose triacetate(CTA) film were carried out using either a conveyor (i.e. dynamic irradiation) or fixed (i.e. static) irradiation. The sample was irradiated using various angles of incidence of electrons, in order to examine the effect of obliqueness of electron incidence at low-energy representative of routine radiation curing of thin polymeric or resin layers. Dynamic irradiation gives broader and shallower depth-dose distributions than static irradiation. Greater obliqueness of incident electrons gives results that can be explained in terms of broader and shallower depth-dose distributions. The back-scattering of incident electrons by a metal(Sn) backing material enhances the absorbed dose in a polymeric layer and changes the overall distribution. It is suggested that any theoretical estimations of the absorbed dose in thin layers irradiated in electron beam curing must be accomplished and supported by experimental data such as that provided by this investigation. (Author)

  13. Mouse skin damages caused by fractionated irradiation with carbon ions

    We have investigated carbon-dose responses of early and late skin damages after daily fractionations to the mouse leg. Depilated legs were irradiated with 7 different positions within 290 MeV/u carbon beams. Fractionation schedules were 1, 2, 4 and 8 daily fractions. Skin reaction was scored every other day for 32 days. Five highest scores in individual mice were averaged, and used as averaged peak reaction. The isoeffect doses to produce an averaged peak skin reaction of 3.0 (moist desquamation) on dose-response curves were calculated with 95% confidence limit. The isoeffect dose for control gamma rays constantly increased with an increase in the number of fraction. The isoeffect doses in low LET carbon ions of 14- and 20 keV/μm also increased up to 4 fractions, but did not increase when 4 fractions increased to 8 fractions. The saturation of isoeffect dose was more prominently observed for 40 keV/μm in such that the isoeffect doses did not change among 2, 4 and 8 fractions. The isoeffect doses for LET higher than 50 keV/μm were smaller than those for lower LET. However, the isoeffect doses for 50-, 60-, 80- and 100 keV/μ steadily increased with an increase in the number of fraction and did not show any saturation up to 8 fractions. Relation between LET and RBE was linear for all fractionation schedules. The slope of regression line in 4 fractions was steepest, and significantly (P<0.05) different from that in 1 fraction. (orig.)

  14. Mouse skin damages caused by fractionated irradiation with carbon ions

    Ando, K.; Chen, Y.J.; Ohira, C.; Nojima, K.; Ando, S.; Kobayashi, N.; Ohbuchi, T.; Shimizu, W. [Space and Particle Radiation Science Research Group, Chiba (Japan); Koike, S.; Kanai, T. [National Inst. of Radiological Sciences, Chiba (Japan). Div. of Accelerator Physics

    1997-09-01

    We have investigated carbon-dose responses of early and late skin damages after daily fractionations to the mouse leg. Depilated legs were irradiated with 7 different positions within 290 MeV/u carbon beams. Fractionation schedules were 1, 2, 4 and 8 daily fractions. Skin reaction was scored every other day for 32 days. Five highest scores in individual mice were averaged, and used as averaged peak reaction. The isoeffect doses to produce an averaged peak skin reaction of 3.0 (moist desquamation) on dose-response curves were calculated with 95% confidence limit. The isoeffect dose for control gamma rays constantly increased with an increase in the number of fraction. The isoeffect doses in low LET carbon ions of 14- and 20 keV/{mu}m also increased up to 4 fractions, but did not increase when 4 fractions increased to 8 fractions. The saturation of isoeffect dose was more prominently observed for 40 keV/{mu}m in such that the isoeffect doses did not change among 2, 4 and 8 fractions. The isoeffect doses for LET higher than 50 keV/{mu}m were smaller than those for lower LET. However, the isoeffect doses for 50-, 60-, 80- and 100 keV/{mu} steadily increased with an increase in the number of fraction and did not show any saturation up to 8 fractions. Relation between LET and RBE was linear for all fractionation schedules. The slope of regression line in 4 fractions was steepest, and significantly (P<0.05) different from that in 1 fraction. (orig.)

  15. Glycolytic metabolism and tumour response to fractionated irradiation

    Background and purpose: To study whether pre-therapeutic lactate or pyruvate predict for tumour response to fractionated irradiation and to identify possible coherencies between intermediates of glycolysis and expression levels of selected proteins. Materials and methods: Concentrations of lactate, pyruvate, glucose and ATP were quantified via bioluminescence imaging in tumour xenografts derived from 10 human head and neck squamous cell carcinoma (HNSCC) lines. Tumours were irradiated with 30 fractions within 6 weeks. Expression levels of the selected proteins in tumours were measured at the mRNA and protein level. Tumour-infiltrating leucocytes were quantified after staining for CD45. Results: Lactate but not pyruvate concentrations were significantly correlated with tumour response to fractionated irradiation. Lactate concentrations in vivo did not reflect lactate production rates in vitro. Metabolite concentrations did not correlate with GLUT1, PFK-L or LDH-A at the transcriptional or protein level. CD45-positive cell infiltration was low in the majority of tumours and did not correlate with lactate concentration. Conclusions: Our data support the hypothesis that the antioxidative capacity of lactate may contribute to radioresistance in malignant tumours. Non-invasive imaging of lactate to monitor radiation response and testing inhibitors of glycolysis to improve outcome after fractionated radiotherapy warrant further investigations.

  16. Absorbed dose distribution analyses in irradiation with adjacent fields

    Because the special irradiation technique with adjacent fields is the most used in the case of medulloblastoma treatment, we consider very important to specify some general information about medulloblastoma. This malignant disease has a large incidence in children with age between 5-7 years. This tumor usually originates in the cerebellum and is referred to as primitive undifferentiated tumor. It may spread contiguously to the cerebellar peduncle, floor of the fourth ventricle, into the cervical spine. In addition, it may spread via the cerebrospinal fluid intracranially and/or to the spinal cord. For this purpose it is necessary to perform a treatment technique with cranial tangential fields combined with adjacent fields for the entire spinal cord to achieve a perfect coverage of the zones with malignant cells. The treatment in this case is an association between surgery-radio-chemotherapy, where the radiotherapy has a very important roll and a curative purpose. This is due to the fact that the migration of malignant cells in the body can't be controlled by surgery. Because of this special irradiation technique used in medulloblastoma treatment, we chase to describe in this paper this complex type of irradiation where the implications of the beams divergence in doses distribution are essentials

  17. Spheroid control of malignant glioma cell lines after fractionated irradiation

    Spheroid control doses (SCD50) were determined for ten human glioma lines after fractionated irradiation under oxic conditions. In addition, SF2 values and colony forming efficiencies (CFE) were measured in a soft agarose clonogenic assay. A significant relationship existed between the SCD50 values and the SF2CFE data pairs (p=0.01) but the SCD50 values were higher than expected from the SF2 and CFE values. This comparison shows the influence of environmental factors (different in both model systems) on reproductive tumour cell death after irradiation. (author). figs., tab

  18. Assessment of specific absorbed fractions for photons and electrons using average adult Japanese male phantom

    The International Commission on Radiological Protection (ICRP) is revising dose coefficients, which are effective and equivalent doses per unit intake of radionuclides, based on the 2007 Recommendations. Specific absorbed fractions (SAFs) of voxel phantoms having standard physiques and organ masses (physical characteristics) of Caucasian are used for calculation of the new dose coefficients. SAFs depend on physical characteristics of a phantom used for assessment of the SAFs. Therefore, the SAFs and the dose coefficients developed by ICRP reflect physical characteristics of Caucasian. On the other hand, physiques of adult Japanese are generally smaller than those of adult Caucasian, and organ masses are also different from each other. Consequently, it is expected that SAFs and dose coefficients with physical characteristics of adult Japanese are different from those of ICRP. It is important to understand the influence of the differences in physical characteristics between both races on SAFs and dose coefficients when using the SAFs and dose coefficients of ICRP for radiation protection for Japanese. In order to evaluate internal doses considering the physical characteristics of adult Japanese, the Japan Atomic Energy Agency plans to develop a comprehensive data set of SAFs for photons, electrons, alpha particles and neutrons using average adult Japanese male and female phantoms (male: JM-103, female: JF-103). This report presents a data set of photon and electron SAFs for JM-103. JM-103 was incorporated into the general purpose radiation transport code, MCNPX 2.6.0, and the SAFs were calculated by the MCNPX 2.6.0 for 25 energies from 10 keV to 10 MeV and for combinations of 67 source regions and 41 target organs. Influences of differences in physical characteristics between adult Japanese and Caucasian on SAFs was also examined by comparison between the calculated SAFs in this study and the SAFs of the reference adult male phantom of ICRP. The photon and electron

  19. Photon and electron specific absorbed fractions for the University of Florida paediatric hybrid computational phantoms

    The University of Florida has developed a set of computational phantoms which originated from real human anatomy in the form of computed tomography (CT) image sets. The organ shapes, orientation, and placement of the internal anatomy were directly determined from these image sets, imported into a 3D graphics program Rhinoceros, and scaled to ICRP reference values. Rhinoceros employs a method of volume description called non-uniform rational B-spline (NURBS) surfaces. Any given volume is described by the boundary created by these surfaces. The surfaces themselves are easy to manipulate, so non-reference body morphometries are readily modeled. The majority of the gross human anatomy was created using NURBS surfaces, but the skeleton was treated separately due to its complexity. A skeletal model with delineated cortical bone and spongiosa/medullary cavity regions was created and imported into Rhinoceros and left in polygon mesh format. Surfaces are initially in polygon mesh format when imported. They are subsequently converted to NURBS surfaces. The result was a model which combines the anatomic realism of actual human anatomy with the simple deformability of stylized models. This class of phantom was termed the ''hybrid'' phantom. Male and female models were created for the ICRP reference ages of newborn, 1 year, 5 years, 10 years, and 15 years. The process for performing internal dosimetry for non-skeletal anatomy is relatively straight forward. Using MCNPX 2.6, radiation transport is performed, and the energy deposited in any given target organ is tallied and divided by the total energy emitted from any given source organ and the target organ's mass. This calculation yields the specific absorbed fraction or SAF, which contains the critical geometric information needed to perform accurate dose calculations for any nuclear medicine procedure. Coupled with the total number of transformations in the source organ and the radionuclide's radiation energies and yields, a

  20. The characteristics and mechanism of apoptosis induced by internal irradiation

    Apoptosis in tumor cells induced by radionuclides is likely the most effective way to cure cancer. In order to explore the possibility in clinic application, the characteristics and mechanism of apoptosis induced by internal irradiation were investigated. The apoptosis and expressions of bcl-2mRNA, bcl-2 and bax of K562 cells following internal exposure with different accumulated absorbed doses of strontium-89 were studied. 6 h after irradiation, the characteristics of apoptosis and necrosis appeared in K562 cells. The apoptosis and necrosis enhanced with the prolongation of internally contaminated time at 6 h, 9 h, 12 h, 24 h and 48 h. The expressions of bcl-2mRNA decreased at 12 h, most remarkably at 24 h. The expressions of bcl-2 decreased after irradiation whereas bax had no obvious changes. The results suggest that the apoptosis induced by internal exposure may be regulated by lower expressions of bcl-2mRNA and bcl-2, lower bcl-2/bax value

  1. Analytical formulae in fractionated irradiation of normal tissue

    The new conception of the modeling of the cell tissue kinetics after fractionated irradiation is proposed. The formulae given earlier are compared with experimental data on various normal tissues and further adjustments are considered. The tissues are shown to exhibit several general patterns of behaviour. The repopulation, if it takes place, seems to start after some time, independently of fractionation in first approximation and can be treated as simple autogenesis. The results are compared with the commonly used NSD conception and the well-known Cohen cell tissue kinetic model

  2. DNA damage induced by radionuclide internal irradiation

    Objective: To study the DNA damage of peripheral blood mononuclear cell (PBMC) in rats exposed to radionuclide internal irradiation. Methods: The radionuclides were injected into the rats and single cell get electrophoresis (SCGE) was performed to detect the length of DNA migration in the rat PBMC. Results: DNA migration in the rat PBMC increased with accumulative dose or dose-rate. It showed good relationship of dose vs. response and of dose-rate vs. response, both relationship could be described as linear models. Conclusion: Radionuclide internal irradiation could cause DNA damage in rat PBMC. (authors)

  3. How to improve the irradiation conditions for the International Fusion Materials Irradiation Facility

    Daum, E

    2000-01-01

    The accelerator-based intense D-Li neutron source International Fusion Materials Irradiation Facility (IFMIF) provides very suitable irradiation conditions for fusion materials development with the attractive option of accelerated irradiations. Investigations show that a neutron moderator made of tungsten and placed in the IFMIF test cell can further improve the irradiation conditions. The moderator softens the IFMIF neutron spectrum by enhancing the fraction of low energy neutrons. For displacement damage, the ratio of point defects to cascades is more DEMO relevant and for tritium production in Li-based breeding ceramic materials it leads to a preferred production via the sup 6 Li(n,t) sup 4 He channel as it occurs in a DEMO breeding blanket.

  4. Effects of carbogen plus fractionated irradiation on KHT tumor oxygenation

    Background and purpose: Numerous studies have demonstrated improvements in the oxygenation of tumor cells following both irradiation and carbogen breathing. The current studies were initiated to measure the combined effects of carbogen inhalation plus single and multi-dose irradiation on tumor oxygen availability, to better define the underlying physiological relationships. Materials and methods: Using KHT murine sarcomas, radiation was delivered to the tumor-bearing legs of non-anesthetized mice. Tumors were quick-frozen prior to or following single or multifraction irradiation and carbogen breathing, and intravascular HbO2 saturation profiles were determined cryospectrophotometrically. Results: HbO2 levels for blood vessels located near the tumor surface initially decreased following 10 Gy irradiation, then increased and remained elevated. Interior HbO2 levels remained unchanged. Following 2.5 Gy, HbO2 changes were minimal. At 24 h following 10 Gy, HbO2 levels were significantly increased compared to non-irradiated controls, and carbogen breathing produced no additional benefit. At 24 h following five fractions of 2 Gy, HbO2 levels throughout the tumor volume were significantly higher in carbogen breathing animals than in air breathing controls. Conclusions: Although peripheral blood vessels demonstrated substantial improvements in oxygenation following irradiation, oxygen availability nearer the tumor center remained at very low levels. The utility of carbogen in enhancing tumor oxygen availability was maintained following five clinically relevant fractions. At higher doses, radiation-induced enhancements in HbO2 levels overshadowed the carbogen effect. For either air or carbogen breathing, a decrease in the percentage of vessels with very low oxygen content did not appear to be a major factor in the reoxygenation of the KHT tumor

  5. NOAA Climate Data Record (CDR) of Leaf Area Index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), Version 4

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains gridded daily Leaf Area Index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) derived from the NOAA Climate Data...

  6. International standards and agreements in food irradiation

    Full text: The economies of both developed and developing countries have been effected by their exported food and agricultural products. Trading policies of food and agricultural products are governed by international agreement as well as national regulations. Trade in food and agricultural commodities may be affected by both principal Agreements within the overall World Trade Organization (WTO) Agreement, though neither specifically refers to irradiation or irradiated foods. The principal Agreements are the Technical Barriers to Trade (TBT) Agreement and the Sanitary and Phyto sanitary (SPS) Agreement. The SPS of the WTO requires governments to harmonize their sanitary and phyto sanitary measures on as wide basis as possible. Related standards, guidelines and recommendations of international standard setting bodies such as the Codex Alimentarius Commission (food safety); the International Plant Protection Convention (IPPC) (plant health and quarantine); and International Office of Epizootic (animal health and zoo noses) should be used in such a harmonization. International Standards for Phyto sanitary Measures (ISPM) no.18 was published under the IPPC by FAO (April 2003, Rome-Italy). ISPM standard provides technical guidance on the specific procedure for the application of ionizing radiation as a phyto sanitary treatment for regulated pests or articles. Moreover, Codex Alimentarius Commission, Codex General Standard for Irradiated Foods (Stand 106-1983) and Recommended International Code of Practice were first published in 1983 and revised in March 2003. Scope of this standard applies to foods processed by ionizing radiation that is used in conjunction with applicable hygienic codes, food standards and transportation codes. It does not apply to foods exposed to doses imparted by measuring instruments used for inspection purposes. Codex documents on Principles and Guidelines for the Import/Export Inspection and Certification of Foods have been prepared to guide

  7. International standards and agreements in food irradiation

    The economies of both developed and developing countries have been effected by their exported food and agricultural products. Trading policies of food and agricultural products are governed by international agreement as well as national regulations. Trade in food and agricultural commodities may be affected by both principal Agreements within the overall World Trade Organization (WTO) Agreement, though neither specifically refers to irradiation or irradiated foods. The principal Agreements are the Technical Barriers to Trade (TBT) Agreement and the Sanitary and Phyto sanitary (SPS) Agreement. The SPS of the WTO requires governments to harmonize their sanitary and phyto sanitary measures on as wide basis as possible. Related standards, guidelines and recommendations of international standard setting bodies such as the Codex Alimentarius Commission (food safety); the International Plant Protection Convention (IPPC) (plant health and quarantine); and International Office of Epizootic (animal health and zoo noses) should be used in such a harmonization. International Standards for Phyto sanitary Measures (ISPM) no.18 was published under the IPPC by FAO (April 2003, Rome-Italy). ISPM standard provides technical guidance on the specific procedure for the application of ionizing radiation as a phyto sanitary treatment for regulated pests or articles. Moreover, Codex Alimentarius Commission, Codex General Standard for Irradiated Foods (Stand 106-1983) and Recommended International Code of Practice were first published in 1983 and revised in March 2003. Scope of this standard applies to foods processed by ionizing radiation that is used in conjunction with applicable hygienic codes, food standards and transportation codes. It does not apply to foods exposed to doses imparted by measuring instruments used for inspection purposes. Codex documents on Principles and Guidelines for the Import/Export Inspection and Certification of Foods have been prepared to guide international

  8. Comparison of One and Two Fractional Irradiation by X-rays on Fibroblasts

    WangJufang; WeyratherWilma

    2003-01-01

    In order to investigate the fractional effect, normal human fibroblasts GM5758 were irradiated with oneand two fractional X-rays. After irradiation, cell survival was performed by standard methods. Cell terminal differentiation pattern was determined as mitotic fibroblasts (MF) Ⅰ, Ⅱ and Ⅲ, post mitotic fibroblasts (PMF) Ⅳ, Ⅴ and Ⅵ, according to cellular morphology, as described by C. Fournier. As show in Fig.l, the survival fraction of two-fraction irradiation is higher than that of one-fraction irradiation. This result suggests that sub-lethal damage induced by radiation can be repaired efficiently for fractional irradiation. As for differentiation

  9. Postirradiation examination of JOYO MK-II control rods. Irradiation performance of absorber pins

    Postirradiation examinations of JOYO MK-II control rods have been carried out since 1983, where 16 subassemblies with total 110 absorber pins of initial load to the fifth reload control rods have been subjected to a number of both non-destructive and destructive examinations. In the course of postirradiation examinations, a cracking of cladding tube was found in the total 15 absorber pins in five control assemblies. This paper indicates the results of postirradiation examinations and analysis of absorber pin performance using CORAL code to elucidate the cause of absorber pin cracking in JOYO MK-II control rods. The cause of cladding failure was attributed to the ACMI where the gap closure due to relocation of B4C pellet took place from early times of irradiation. The code analysis by CORAL indicated that the cladding strain due to ACMI was not fully absorbed by the irradiation creep and that the plastic strain became large enough to make a fracture of absorber pins with an increasing burnup. (J.P.N.)

  10. Solar Multi-stage Refrigeration Systems on the Basis of Absorber with the Internal Evaporative Cooling

    Doroshenko A.V.; Kirillov V.H.; Antonova A.R.; Liudnicky K.V.

    2015-01-01

    In the article, the developed schematics are presented for the alternative refrigeration systems and air-conditioning systems, based on the use of absorbing cycle and solar energy for the regeneration of absorbent solution. Multi-stage principle of construction of drying and cool contours of solar systems is used with growth of concentration of absorbent on the stages of cooler. An absorber with internal evaporative cooling, allowing to remove the separate evaporated cooler, usually included ...

  11. Study on Fractionated Total Body Irradiation before Hematopoietic Stem Cell Transplantation

    Tong Fang; Bo Liu; Hong Gao

    2009-01-01

    OBJECTIVE To observe the dose and the complications from total body irradiation before hematopoietic stem cell transplantation.METHODS This study involved 312 patients with total body irradiation before hematopoietic stem cell transplantation. They were entered into the treated research from May 1999 to October 2005. All patients had Received the irradiation from 60Co of an absorbed dose rate of (5.2 ± 1.13) cGy/min. The total dose of TBI was 7~12 Gy, 1 f/d × 2 d. A high-dose rate group (≥ 10 Gy) included 139 cases and a low-dose rate group (< 10 Gy) included 173 cases.RESULTS The probability of acute gastrointestinal reactions in the high-dose rate group was more compared with that in the low-dose rate group. The differences for other reactions, such as hematopoietic reconstitution and graft survival rate, between the two groups were insignificant.CONCLUSION Using fractional total body irradiation at a dose rate of 5 cGy/min, with a total dose of 7~12 Gy, 1 f/d x 2 d, with the lung receiving under 7.5 Gy is a safe and effective pretreatment for hematopoietic stem cell transplantation.

  12. Food Irradiation. Proceedings of the International Symposium on Food Irradiation

    For some years research has been done in several countries, with the object of contributing to the world's food supplies, on the application of nuclear methods to food preservation and processing. The importance of food preservation is of particular relevance in certain regions of the world where up to thirty per cent of harvested foodstuffs are being lost because of damage by animal pests and microorganisms. A series of international meetings have been held on this subject; the first, held in 1958 at Harwell, was followed by further meetings in 1960 in Paris and in 1961 in Brussels. The International Symposium on Food Irradiation organized by the International Atomic Energy Agency and the Food and Agriculture Organization of the United Nations through their Joint Division of Atomic Energy in Agriculture, and held at the Karlsruhe Nuclear Research Centre, Karlsruhe, from 6 to 10 June 1966, at the generous invitation of the Government of the Federal Republic of Germany, is the most recent of this series of meetings. It was held for the purpose of exchanging the most up-to-date results of research, of contributing towards co-operative efforts between Member States, and of stimulating trade in the international exchange of irradiated products between nations. Papers describing research over the past fourteen years were given by outstanding authorities; the results point to a breakthrough having been achieved in the use of ionizing radiation in food preservation, notwithstanding some problems still to be solved, such as overcoming changes in colour, flavour, odour or texture. The Symposium was attended by over 200 scientists from 25 countries and four international organizations. Sixty-nine papers were presented. It was shown that a wide variety of foodstuffs exist for which radiation could be used for three different purposes: to produce indefinitely stable products, to rid food of organisms that constitute health hazards, and to extend the normal shelf or market life

  13. Identification and absorbed dose determination in irradiated kiwi by electron paramagnetic resonance

    A methodology for identification and absorbed dose determination in irradiated Kiwi with doses between 200 and 1000 Gy is present. Measurement are performed by Electron Paramagetic Resonance (ESR) in the flesh of the fruit after alcohol extration that removes water and soluble substances. The signal used is the radial produced in cellulose by radiation that shows to be stable during the usefull life of the fruit and that is not present in non-irradiated samples. Reference samples are not necessary to dose determination and the results shows that 85% of the calculated values are found to be within ± 15% of the applied initial dose. (author). 9 refs., 5 figs., 2 tabs

  14. Methods to verify absorbed dose of irradiated containers and evaluation of dosimeters

    The research on dose distribution in irradiated food containers and evaluation of several methods to verify absorbed dose were carried out. The minimum absorbed dose of treated five orange containers was in the top of the highest or in the bottom of lowest container. Dmax/Dmin in this study was 1.45 irradiated in a commercial 60Co facility. The density of orange containers was about 0.391g/cm3. The evaluation of dosimeters showed that the PMMA-YL and clear PMMA dosimeters have linear relationship with dose response, and the word NOT in STERIN-125 and STERIN-300 indicators were covered completely at the dosage of 125 and 300 Gy respectively. (author)

  15. An international dosimetry exchange for boron neutron capture therapy. Part I: Absorbed dose measurements.

    Binns, P J; Riley, K J; Harling, O K; Kiger, W S; Munck af Rosenschöld, P M; Giusti, V; Capala, J; Sköld, K; Auterinen, I; Serén, T; Kotiluoto, P; Uusi-Simola, J; Marek, M; Viererbl, L; Spurny, F

    2005-12-01

    An international collaboration was organized to undertake a dosimetry exchange to enable the future combination of clinical data from different centers conducting neutron capture therapy trials. As a first step (Part I) the dosimetry group from the Americas, represented by MIT, visited the clinical centers at Studsvik (Sweden), VTT Espoo (Finland), and the Nuclear Research Institute (NRI) at Rez (Czech Republic). A combined VTT/NRI group reciprocated with a visit to MIT. Each participant performed a series of dosimetry measurements under equivalent irradiation conditions using methods appropriate to their clinical protocols. This entailed in-air measurements and dose versus depth measurements in a large water phantom. Thermal neutron flux as well as fast neutron and photon absorbed dose rates were measured. Satisfactory agreement in determining absorbed dose within the experimental uncertainties was obtained between the different groups although the measurement uncertainties are large, ranging between 3% and 30% depending upon the dose component and the depth of measurement. To improve the precision in the specification of absorbed dose amongst the participants, the individually measured dose components were normalized to the results from a single method. Assuming a boron concentration of 15 microg g(-1) that is typical of concentrations realized clinically with the boron delivery compound boronophenylalanine-fructose, systematic discrepancies in the specification of the total biologically weighted dose of up to 10% were apparent between the different groups. The results from these measurements will be used in future to normalize treatment plan calculations between the different clinical dosimetry protocols as Part II of this study. PMID:16475772

  16. SOLAR REFRIGERATION SYSTEMS BASED ON THE ABSORBER WITH INTERNAL EVAPORATIVE COOLING

    Дорошенко, O.В.; Людницький, К.В.

    2015-01-01

    The paper presents the developed schematics for alternative refrigeration systems and air conditioning systems based on the use of heat-absorption cycle and solar energy for regeneration (recovery) of the absorbent solution. Cascade principle of construction of the drying and cooling circuits with absorbent concentration increasing on the steps of the cascade is used. The absorber with internal evaporative cooling that eliminates a separate evaporative cooler, typically comprised after the co...

  17. Quality assurance program of a respiratory gating irradiation system based on external and internal fiducial markers

    Respiratory Gating involves the administration of radiation during treatment delivery within a particular portion of the patients breathing cycle, so the absorbed dose administration with respiratory control techniques requires specific quality control to ensure the correctness of the delivered dose. The establishment of a Quality Control Program (QC) is proposed for the Respiratory Gating based techniques in order to have a better understanding of how this system works and to know its associated dosimetric impact. The influence of the CT acquisition under respiratory motion conditions has been analyzed for the treatment isocenter localization, using internal and external fiducial markers with IGRT techniques that allow the correlation of the isocenter positioning with the phase of the respiratory cycle. Radiation delivery in the presence of intra fraction organ motion causes an averaging or blurring of the static dose distribution over the path of motion increasing the beam penumbra of the radiation field and reducing the therapeutic region when the irradiation is not breath controlled. The feasibility of intensity modulated treatments (IMRT) for both static and dynamic techniques, managed by respiratory control has been tested, demonstrating the possibility of synchronizing the movement of the leaves in the microfluorimeter collimator (mMLC) with the gated beam irradiation. (Author) 45 refs.

  18. Comparison of photon and electron absorbed fractions in voxel-based and simplified phantoms for small animals

    Internal dosimetry on non-human biota is getting more important from the view point of radiation protection of environment. The International Commission on Radiological Protection (ICRP) proposed the Reference Animals and Plants using simplified phantoms, such as ellipsoids and spheres, and assessed absorbed fractions (AFs) for the whole bodies. In this study, photon and electron AFs in whole body of voxel-based frog and mouse phantoms were evaluated and compared with AFs in simplified phantoms. The evaluations were done by Monte Carlo methods for voxel-based and simplified phantoms. The monoenergetic photon or electron source was considered to be distributed uniformly in whole body. There were very small differences (less than 2%) between whole-body AFs in voxel-based and simplified mouse phantoms however the differences were up to 24% for the voxel-based and the Reference Frog phantoms. Whole-body AFs in voxel-based and simplified phantoms demonstrated that not only mass but also shape of whole body effected on AFs significantly. The results of this study suggest the replacement of the Reference Animal phantoms by voxel-based animal phantoms to improve the accuracy of the whole-body AFs. (author)

  19. Determination of absorbed dose in the experimental animal irradiated on the Leksell gamma knife

    The purpose of this study was to evaluate and quantify inaccuracy of Leksell GammaPlan relative and absolute dose calculations for the experimental animal and to determine necessary corrections that must be applied. Both TLD and semiconductor detectors appeared to be suitable for measurement of absorbed dose in the rat brain irradiated on the Leksell gamma knife. Both detectors, due to their size, measured mean doses, nay doses to maximum. The Leksell GammaPlan treatment planning system can be employed for the calculation of absorbed doses even in such an extreme condition like irradiation of experimental animals. However, in our concrete case, it was necessary to apply correction factor of 1.0779 for the absolute absorbed dose to obtain reliable results. Comparison of dose profiles in all three axis calculated by the treatment planning system and measured ones by polymer gel dosimeter showed acceptable agreement. Results presented in this study are strictly related to the Leksell GammaPlan treatment planning system and the special fixation device developed in Na Homolce Hospital. (authors)

  20. Absorbed dose assessment in particle-beam irradiated metal-oxide and metal-nonmetal memristors

    Knežević Ivan D.

    2012-01-01

    Full Text Available Absorbed dose was estimated after Monte Carlo simulation of proton and ion beam irradiation on metal-oxide and metal-nonmetal memristors. A memristive device comprises two electrodes, each of a nanoscale width, and a double-layer active region disposed between and in electrical contact with electrodes. Following materials were considered for the active region: titanium dioxide, zirconium dioxide, hafnium dioxide, strontium titanium trioxide and galium nitride. Obtained results show that significant amount of oxygen ion - oxygen and nonmetal ion - nonmetal vacancy pairs is to be generated. The loss of such vacancies from the device is believed to deteriorate the device performance over time. Estimated absorbed dose values in the memristor for different constituting materials are of the same order of magnitude because of the close values of treshold displacement energies for the investigated materials.

  1. International standards, Agreements and Policy of food Irradiation

    There are few internationally recognised standards and agreements related to irradiated foods. Codex Alimentarius has its General standard for Irradiated foods. This sets standards for the production of irradiated foods that are safe and nutritionally adequate. Guidelines for the proper processing of foods by irradiation are covered in the Codex Recommended International Code of Practice for the Operation of Radiation Facilities Used for the Treatment of Food. For irradiation as a quarantine treatment for fruit, vegetables and other plants, the relevant international organization is the International Plant Protection Convention (IPPC), IPPC has no standards or guidelines for irradiation treatments. However, regional organizations within IPPC are moving towards recognition of irradiation as a technically viable and effective method of insect disinfestation. Especially notable are actions within the North American Plant Protection Organisation (NAPPO). NAPPO has endorsed a standard on the use of irradiation as a quarantine treatment. Other speakers have provided considerable detail on the Codex standard and on the situation with regard to quarantine issues. In this talk I will concentrate on irradiated foods as commodities that will be traded internationally in increasing amounts as we approach the next century. International trade is governed by bilateral arrangements. However, these arrangements should be consistent with the overarching multilateral agreements of the World trade Organization (WTO). The WTO Agreements do not refer directly to irradiation or irradiated foods. However, in this talk I will try to interpret the implications of the Agreements for trade in irradiated food. (Author)

  2. Synthesis of hemicellulose-acrylic acid graft copolymer super water absorbent resin by ultrasonic irradiation technology

    Liu, Fangfang; Conghui DU; Linya ZHANG

    2015-01-01

    The hemicellulose super water absorbent resin is prepared by using ultrasonic irradiation technology, with the waste liquid produced during the preparation of viscose fiber which contains a large amount of hemicellulose as raw material, acrylic acid as graft monomer, N,N’-methylene bis acrylamide (NMBA) as cross linking agent, and (NH4)2S2O8-NaHSO3 as the redox initiation system. The synthesis conditions, structure and water absorption ability of resin are discussed. The results indicate that...

  3. Kantian fractionalization predicts the conflict propensity of the international system

    Cranmer, Skyler J; Mucha, Peter J

    2014-01-01

    The study of complex social and political phenomena with the perspective and methods of network science has proven fruitful in a variety of areas, including applications in political science and more narrowly the field of international relations. We propose a new line of research in the study of international conflict by showing that the multiplex fractionalization of the international system (which we label Kantian fractionalization) is a powerful predictor of the propensity for violent interstate conflict, a key indicator of the system's stability. In so doing, we also demonstrate the first use of multislice modularity for community detection in a multiplex network application. Even after controlling for established system-level conflict indicators, we find that Kantian fractionalization contributes more to model fit for violent interstate conflict than previously established measures. Moreover, evaluating the influence of each of the constituent networks shows that joint democracy plays little, if any, rol...

  4. Solar Multi-stage Refrigeration Systems on the Basis of Absorber with the Internal Evaporative Cooling

    Doroshenko A.V.

    2015-08-01

    Full Text Available In the article, the developed schematics are presented for the alternative refrigeration systems and air-conditioning systems, based on the use of absorbing cycle and solar energy for the regeneration of absorbent solution. Multi-stage principle of construction of drying and cool contours of solar systems is used with growth of concentration of absorbent on the stages of cooler. An absorber with internal evaporative cooling, allowing to remove the separate evaporated cooler, usually included after the absorber of the proper stage, is developed. Heat-mass-transfer apparatus of film-type, entering in the complement of drying and cool contours compatible and executed on the basis of multichannel compositions from polymeric materials. The preliminary comparative analysis of possibilities of the solar refrigeration systems and air-conditioning systems is executed.

  5. Development of fluorescent, oscillometric and photometric methods to determine absorbed dose in irradiated fruits and nuts

    To ensure suitable quality control at food irradiation technologies and for quarantine authorities, simple routine dosimetry methods are needed for absorbed dose control. Taking into account the requirements at quarantine locations these methods would require nondestructive analysis for repeated measurements. Different dosimetry systems with different analytical evaluation methods have been tested and/or developed for absorbed dose measurements in the dose range of 0.1-10 kGy. In order to use the well accepted ethanolmonochlorobenzene dosimeter solution and the recently developed aqueous alanine solution in small volume sealed vials, a new portable, digital, and programmable oscillometric reader was developed. To make use of the availability of the very sensitive fluorimetric evaluation method, liquid and solid inorganic and organic dosimetry systems were developed for dose control using a new routine, portable, and computer controlled fluorimeter. Absorption or transmission photometric methods were also applied for dose measurements of solid or liquid phase dosimeter systems containing radiochromic dye agents, which change colour upon irradiation. (author)

  6. Curcumin Stimulates the Antioxidant Mechanisms in Mouse Skin Exposed to Fractionated γ-Irradiation

    Ganesh Chandra Jagetia; Golgod Krishnamurthy Rajanikant

    2015-01-01

    Fractionated irradiation is one of the important radiotherapy regimens to treat different types of neoplasia. Despite of the immense therapeutic gains accrued by delivering fractionated irradiation to tumors, the radiation burden on skin increases significantly. Low doses of irradiation to skin adversely affect its molecular and metabolic status. The use of antioxidant/s may help to alleviate the radiation-induced changes in the skin and allow delivering a higher dose of radiation to attain b...

  7. Role and activities of international consultative group on food irradiation

    This paper discusses the formation of a consultative group to focus on international cooperation on food irradiation. The functions of the group include studying such items as legislation, wholesomeness of irradiated food, safety, trade and technical training, marketing and labelling and providing an inventory of food irradiation facilities. (U.K.)

  8. About some aspects of absorbed and effective ionizing radiation dose computation of population under external and internal radiation influence

    The purpose of the investigation is to develop methods of dose assessment, absorbed by individual human organs, or effective dose of population, as well as to study factors effecting on uncertainties in their computation. The dose assessment for the Thyroid or other organ is based on retrospective information obtained from radioecological monitoring and according to the information about radioactive fallout's on the surface after each nuclear test, as well as the information about concrete living conditions of local population. The main parameter in proposed algorithms is gamma-radiation dose rate at open area, which is a result of direct measurements. When assessing internal radiation dose, in the course of inhalation, the whole period of local fallout's is taken into consideration. The developed method allows obtaining a systematic information describing irradiation of people by means of the radioactive traces, as well as tabulated information for model computations of internal and external radiation dose

  9. Recent international developments regarding standardization of food irradiation treatment

    The recommendations of the Joint Expert Committee on Food Irradiation at its 1976 and 1979 meetings, published by WHO/FAO/IAEA in 1977 and 1980 are discussed in relation to the Recommended Codex International General Standard for Irradiated Food and the Recommended International Code of Practice for the Operation of Radiation Facilities Used for the Treatment of Foods, which are based on them. The texts of these documents are appended. The problem of labelling irradiated foods is discussed

  10. Dependence of microwave absorption properties on ferrite volume fraction in MnZn ferrite/rubber radar absorbing materials

    Gama, Adriana M.; Mirabel C. Rezende; Dantas, Christine C.

    2011-01-01

    We report the analysis of measurements of the complex magnetic permeability ($\\mu_r$) and dielectric permittivity ($\\epsilon_r$) spectra of a rubber radar absorbing material (RAM) with various MnZn ferrite volume fractions. The transmission/reflection measurements were carried out in a vector network analyzer. Optimum conditions for the maximum microwave absorption were determined by substituting the complex permeability and permittivity in the impedance matching equation. Both the MnZn ferri...

  11. Understanding and predicting the behaviour of silver base neutron absorbers under irradiations

    The effect of neutron irradiation induced transmutations on the swelling of AgInCd (AIC) alloys used as neutron absorber in the control rods of Pressurized Water Reactors has been studied both experimentally and theoretically. Effective atomic volumes have been determined in synthetic AgCdInSn alloys with various compositions and containing fcc and hc phases, representative of irradiated AIC (Sn is a transmutation product). Swelling is shown to result first from the transmutation of Ag into Cd and of In into Sn, both with larger effective volume than the mother atom, and second from grain boundaries precipitation of s still less dense hc phase when solid solubility of transmuted products is exceeded. For both fcc and hc phases, we have determined profiles at the temperatures in the vicinity of the operating temperature. Unusual characteristics of second phase growth at grain boundaries induced by transmutations are identified on a simple binary alloy model: kinetics is controlled by irradiation temperature which scales diffusivities and flux which scales transmutation rates, as well as by the grain size in the underlying matrix. To address the AgInCdSn alloys, a novel technique is proposed to model diffusion in multicomponent alloys. It is based on a linearization of a simple atomistic model. With a single set of parameters, for each phase, our model well reproduces our interdiffusion measurements in quaternary alloys as well as existing interdiffusion experiments in binary alloys. Finally this diffusion model implemented with a moving interface algorithm is used to model the growth of the second phase induced by transmutation in the AIC under irradiation. (authors)

  12. Swelling and phenol absorbing property of Xanthan gum-g-N-vinylpyrrolidone prepared by irradiation

    Xanthan gum-g-N-vinylpyrrolidone graft copolymer (XG-g-NVP) was prepared by irradiation, and its swelling and phenol absorbing properties were studied. Results showed that the XG-g-NVP had the best swelling property (62.1 g/g) and the best phenol adsorption capacity (0.76 g/g) at the grafting yield of 623%. IR analysis showed that the copolymer was combined with phenol through hydrogen bonds. The data of isotherm were fitted to Freundlich model. At the temperature of 298 K, free energy (ΔG) of the adsorption process was -2.586 kJ/mol. Thus identified that the process was a physical adsorption and spontaneously occurred. Therefore, XG-g-NVP could be used as a highly effective adsorbent for wastewater treatment. (authors)

  13. A model for assessing cognitive impairment after fractionated whole-brain irradiation in nonhuman primates.

    Robbins, Mike E; Bourland, J Daniel; Cline, J Mark; Wheeler, Kenneth T; Deadwyler, Sam A

    2011-04-01

    To investigate the effect of fractionated whole-brain irradiation on nonhuman primates, 6-9-year-old male rhesus monkeys were irradiated with 40 Gy delivered as two 5-Gy fractions/week for 4 weeks. Cognitive function was assessed 5 days/week for 4 months prior to fractionated whole-brain irradiation and for 11 months after irradiation using a Delayed-Match-to-Sample (DMS) task at both low and high cognitive loads. Local rates of cerebral glucose metabolism were measured prior to and 9 months after irradiation using [(18)F]-2-deoxy-2-fluoro-d-glucose positron emission tomography. Low cognitive load trials did not reveal a significant reduction in performance until 7 months after irradiation; performance then declined progressively. In high cognitive load trials, the initial impairment was observed ∼1 month after irradiation. This was followed by a transient recovery period over the next 1-2 months, after which performance declined progressively through 11 months after irradiation. Nine months after irradiation, glucose uptake during the DMS task was decreased in the cuneate and prefrontal cortex and was increased in the cerebellum and thalamus compared with the levels prior to irradiation. Results from this pilot study suggest that the radiation-induced changes in cognition and brain metabolism observed in rhesus monkeys may be similar to those observed in brain tumor patients receiving brain irradiation. PMID:21275607

  14. A Comparison of Model Calculation and Measurement of Absorbed Dose for Proton Irradiation. Chapter 5

    Zapp, N.; Semones, E.; Saganti, P.; Cucinotta, F.

    2003-01-01

    With the increase in the amount of time spent EVA that is necessary to complete the construction and subsequent maintenance of ISS, it will become increasingly important for ground support personnel to accurately characterize the radiation exposures incurred by EVA crewmembers. Since exposure measurements cannot be taken within the organs of interest, it is necessary to estimate these exposures by calculation. To validate the methods and tools used to develop these estimates, it is necessary to model experiments performed in a controlled environment. This work is such an effort. A human phantom was outfitted with detector equipment and then placed in American EMU and Orlan-M EVA space suits. The suited phantom was irradiated at the LLUPTF with proton beams of known energies. Absorbed dose measurements were made by the spaceflight operational dosimetrist from JSC at multiple sites in the skin, eye, brain, stomach, and small intestine locations in the phantom. These exposures are then modeled using the BRYNTRN radiation transport code developed at the NASA Langley Research Center, and the CAM (computerized anatomical male) human geometry model of Billings and Yucker. Comparisons of absorbed dose calculations with measurements show excellent agreement. This suggests that there is reason to be confident in the ability of both the transport code and the human body model to estimate proton exposure in ground-based laboratory experiments.

  15. Study of the spatial distribution of the absorbed dose in blood volumes irradiated using a teletherapy unit

    Blood irradiation can be performed using a dedicated blood irradiator or a teletherapy unit. A thermal device providing appropriate storage conditions during blood components irradiation with a teletherapy unit has been recently proposed. However, the most appropriated volume of the thermal device was not indicated. The goal of this study was to indicate the most appropriated blood volume for irradiation using a teletherapy unit in order to minimize both the dose heterogeneity in the volume and the blood irradiation time using these equipments. Theoretical and experimental methods were used to study the dose distribution in the blood volume irradiated using a linear accelerator and a cobalt-60 therapy machine. The calculation of absorbed doses in the middle plane of cylindrical acrylic volumes was accomplished by a treatment planning system. Experimentally, we also used cylindrical acrylic phantoms and thermoluminescent dosimeters to confirm the calculated doses. The data obtained were represented by isodose curves. We observed that an irradiation volume should have a height of 28 cm and a diameter of 28 cm and a height of 35 cm and a diameter of 35 cm, when the irradiation is to be performed by a linear accelerator and a cobalt-60 teletherapy unit, respectively. Calculated values of relative doses varied from 93% to 100% in the smaller volume, and from 66% to 100% in the largest one. A difference of 5.0%, approximately, was observed between calculated and experimental data. The size of these volumes permits the irradiation of blood bags in only one bath without compromising the homogeneity of the absorbed dose over the irradiated volume. Thus, these irradiation volumes can be recommend to minimize the irradiation time when a teletherapy unit is used to irradiate blood.

  16. Internal radiation absorbed dose estimation in human brain due to technetium-99m and iodine-131

    Internal dosimetry is a branch of medical physics that deals with the measurement of the internally absorbed dose by an organ after applying isotopes. In this study, internal radiation absorbed dose has been calculated for 99mTc and 131I, which are frequently used for functioning tests and therapeutic treatments of thyroid, respectively in these cases, some amount of isotopes are accumulated in other tissues like brain, which are very soft and cannot be regenerated if they are damaged. Using ionizing radiation inside the body and to ensure the safety of brain, the internal radiation absorbed dose has been calculated applying direct counting measurement. Accumulation of isotopes to target organ has been measured and this target organ is considered as primary target organ; also this organ is considered as source with respect to other organs. These organ counts have, been measured by computer-based scintillation system. The amount of exposure in brain has been measured with the help of the data obtained from the special set-up equipment, including NaI detector, radiation survey meter and water phantoms of various sizes. Absorbed dose in brain for each isotope has been calculated by applying time-activity curve analysis. Finally, these results have been compared with the data in ICRP l Reports 53 and 71. (author)

  17. Results of post-irradiation examinations of the absorber NS 201 (with pellets) of the KNK II first core

    The absorber NS-201 of the KNK II first core has been unloaded after a residence time of 273 equivalent full-power days, because gap closure between pellet and cladding had to be expected in 24 pins with B4C-pellets. Selected pins of this element underwent post-irradiation examinations in the hot cells of the KfK Karlsruhe. The evaluated and interpreted results of the investigations, which are documented in this report, allow the conclusion that the absorber could have been irradiated for the full core residence time. The good irradiation behaviour of the pellets and the cladding without any visible interaction, lead to the plan for further irradiation of a complete pellet column of one pin in the third core of KNK II

  18. Immunologic changes after loco-regional radiotherapy and fractionated total body irradiation (TBI) in mice

    The immunologic effects of fractionated irradiation to both hind limbs and the tail of adult mice were investigated. A dose of 34 Gy given in 17 fractions of 2 Gy, 1 fraction per day, 5 days per week, was delivered with a 60Co source. A significant decrease of the total splenocyte count and of the PHA(phytohemagglutinin)-induced proliferation of T cells was found immediately after irradiation. Both parameters normalized within 30 days after irradiation. Immediately after irradiation, the MLC (mixed lymphocyte culture) was supranormal, dropped to 45% 1 week later, and normalized within 1 month after radiotherapy. The NK (natural killer) activity was significantly decreased only the first week after loco-regional irradiation, while the LAK (lymphokine activated killer) activity was not altered at all. The percentage of goat-anti-mouse+ cells (mainly B lymphocytes) was not changed immediately after loco-regional irradiation, but rose to supranormal values (175% of control level) 3 months after irradiation. A persistent decrease of the percentage and the absolute numbers of the Lyt2+ cells (= CD8+ cells, suppressor/cytotoxic phenotype) was observed up to 3 months after irradiation, while the percentage of L3T4+ cells (= CD4+ cells, helper phenotype) remained normal for the total follow-up. No differences in allogeneic skin graft survival could be demonstrated between irradiated and control animals. The observed immunological effects could not be explained by the scatter irradiation to the whole body as total body irradiation (TBI) administered in a dose and dose rate similar to the scatter dose did not result in persistent immunologic changes. No dose-rate effect could be demonstrated in a low dose fractionated total body irradiation schedule. A total body irradiation similar to the scatter dose in humans did not result in significant immunologic changes

  19. Secondary absorbed doses from light ion irradiation in anthropomorphic phantoms representing an adult male and a 10 year old child

    Secondary organ absorbed doses were calculated by Monte Carlo simulations with the SHIELD-HIT07 code coupled with the mathematical anthropomorphic phantoms CHILD-HIT and ADAM-HIT. The simulated irradiations were performed with primary 1H, 4He, 7Li, 12C and 16O ion beams in the energy range 100-400 MeV/u which were directly impinging on the phantoms, i.e. approximating scanned beams, and with a simplified beamline for 12C irradiation. The evaluated absorbed doses to the out-of-field organs were in the range 10-6 to 10-1 mGy per target Gy and with standard deviations 0.5-20%. While the contribution to the organ absorbed doses from secondary neutrons dominated in the ion beams of low atomic number Z, the produced charged fragments and their subsequent charged secondaries of higher generations became increasingly important for the secondary dose delivery as Z of the primary ions increased. As compared to the simulated scanned 12C ion beam, the implementation of a simplified beamline for prostate irradiation with 12C ions resulted in an increase of 2-50 times in the organ absorbed doses depending on the distance from the target volume. Comparison of secondary organ absorbed doses delivered by 1H and 12C beams showed smaller differences when the RBE for local tumor control of the ions was considered and normalization to the RBE-weighted dose to the target was performed.

  20. Absorbed dose response of Al2O3 dosimeter irradiated by 60Co γ spectrum source capture and collimators

    Objective: To investigated the absorbed dose response of Al2O3 dosimeter in water phantom irradiated by 60Co γ spectrum source. Methods: The EGSnrc simulation program code DOSRZnrc was used to calculate the absorbed dose of the Al2O3 dosimeter and that of the equivalent volume of water in the corresponding position, as well as the absorbed dose conversion factor, irradiated by 60Co photon beams in a water phantom. Simulations were done for a cylindrical geometry dosimeter (diameter 0.4 cm and height 0.1 cm) and the dosimeter was placed at the centre of the water phantom at different depths. Results: The average absorbed dose conversion factor is 1.143±0.006 and changes little with the depth of the dosimeter in the water phantom, and the deviation is less than 1.0%. Conclusion: The absorbed dose response of Al2O3 dosimeter irradiated by 60Co γ spectrum source is steady and is independent on the depth of the dosimeter in water phantom in this research. (authors)

  1. Effect of Fractionated Doses of Cerastes Cerastes Crude Venom on Tissues of Irradiated Mice

    This Work aims to study the effect of fractionated doses of Cerastes cerastes (C. cerastes) crude venom (CCV) on physiological alterations in different tissues of 5.5 Gy γ-irradiated mice. Male mice were grouped into: Control group. CCV group; mice received via inter peritoneum (i.p.) ⅓LD50 CCV in fractionated doses over a period of 2 weeks. Irradiated group; mice whole body exposed to 5.5 Gy γ-rays. Irradiated+ CCV; mice received via i.p ⅓LD50 CCV in fractionated doses over a period of 2 weeks starting 1 h post irradiation. Exposure to 5.5 Gy γ-rays elevated advanced oxidation protein products (AOPP) and malondialdehyde (MDA) levels and decreased glutathione (GSH) content of liver, spleen and kidney. Moreover, γ-irradiation significantly decreased calcium (Ca) and elevated zinc (Zn), and cupper (Cu) in liver, spleen and kidney tissues compared to the control, whereas, iron (Fe) was significantly elevated in liver and spleen and decreased in kidney. In addition, serum urea and creatinine and their ratio were significantly increased. Irradiated mice treated with fractionated CCV showed significant amelioration of oxidative stress and element alterations in the different tissues. It could be concluded that the fractionated doses of CCV (⅓LD50) might have favourable potential against irradiation induced-biochemical injuries.

  2. Spinal cord tolerance to single-fraction partial-volume irradiation: a swine model

    Medin, P.M.; Foster, R.D.; Kogel, A.J. van der; Sayre, J.W.; McBride, W.H.; Solberg, T.D.

    2011-01-01

    PURPOSE: To determine the spinal cord tolerance to single-fraction, partial-volume irradiation in swine. METHODS AND MATERIALS: A 5-cm-long cervical segment was irradiated in 38-47-week-old Yucatan minipigs using a dedicated, image-guided radiosurgery linear accelerator. The radiation was delivered

  3. The proliferative response of mouse intestinal crypts during fractionated irradiation of carbon beams

    Clonogenic assay of jejunal crypt during carbon beam and X-ray irradiations was performed. Fractionation with top-up dose assay revealed carbon beam irradiations caused more damage than X-ray did. To clarify this problem is urgent. (author)

  4. Internal friction of cold worked and irradiated copper

    The internal friction spectrum of cold worked copper is strongly modified, either by increasing the stress or by introducing irradiation point defects. It is shown that, in copper samples containing suitable dislocation lattices, it is possible to develop a Hasiguti-type peak by electron irradiation

  5. Optical properties of ion irradiated and annealed InGaAs/GaAs quantum wells and semiconductor saturable absorber mirrors

    Optical properties of Ni+ irradiated and thermally annealed InGaAs/GaAs multiple quantum wells and semiconductor saturable absorber mirrors (SESAMs) have been studied using photoluminescence (PL) and non-linear reflectivity measurements. Rapid decrease of PL intensity and lifetime with increasing irradiation dose was accompanied by undesirable degradation of the non-linear optical properties of SESAMs. However, some of the irradiation-created defects could be removed and the non-linear optical properties improved by rapid thermal annealing. The combination of ion irradiation and annealing provided a selective method for controlling the absorption recovery time of SESAMs while preserving the non-linear properties. Irradiation with 1012 cm-2 of 6 MeV Ni+ ions and 1 s annealing at 400 deg. C led to an absorption recovery time of ∼1 ps while the modulation depth, the non-saturable losses and the saturation fluence were all close to their as-grown values

  6. Response Funtions for Computing Absorbed Dose to Skeletal Tissues from Photon Irradiation

    Eckerman, Keith F [ORNL; Bolch, W E [University of Florida, Gainesville; Zankl, M [Institute of Radiation Protection, GSF-National Reserach Center for Environ; Petoussi-Henss, N [Institute of Radiation Protection, GSF-National Reserach Center for Environ

    2007-01-01

    The calculation of absorbed dose in skeletal tissues at radiogenic risk has been a difficult problem because the relevant structures cannot be represented in conventional geometric terms nor can they be visualised in the tomographic image data used to define the computational models of the human body. The active marrow, the tissue of concern in leukaemia induction, is present within the spongiosa regions of trabecular bone, whereas the osteoprogenitor cells at risk for bone cancer induction are considered to be within the soft tissues adjacent to the mineral surfaces. The International Commission on Radiological Protection (ICRP) recommends averaging the absorbed energy over the active marrow within the spongiosa and over the soft tissues within 10 mm of the mineral surface for leukaemia and bone cancer induction, respectively. In its forthcoming recommendation, it is expected that the latter guidance will be changed to include soft tissues within 50 mm of the mineral surfaces. To address the computational problems, the skeleton of the proposed ICRP reference computational phantom has been subdivided to identify those voxels associated with cortical shell, spongiosa and the medullary cavity of the long bones. It is further proposed that the Monte Carlo calculations with these phantoms compute the energy deposition in the skeletal target tissues as the product of the particle fluence in the skeletal subdivisions and applicable fluence-to-dose response functions. This paper outlines the development of such response functions for photons.

  7. Proliferation of human melanoma cells after single and fractionated exposure to hyperthermia and irradiation

    The growth, DNA synthesis, distribution of cells in the cell cycle, labeling index, and the formation of micronuclei were measured in a human melanoma cell line after single and fractionated treatment with hyperthermia (three times for 1 hr at 42 degrees C) and X-irradiation (4.0 gray three times) or a combination of both treatments. After fractionation with heat or irradiation alone, the cells showed a greater capacity for recovery than after fractionation with the combined modality. The DNA synthesis returned to the control values after each fraction at later periods. Concomitant with these observations was a decrease of labeled or unlabeled S-phase cells. The effect was more pronounced after the combined fractionation. Hypoploid cells as potentially dead cells were observed after each treatment, but hyperploid cells were observed only after the combined fractionation. According to the cell loss and occurrence of hypoploid cells, micronuclei increased except after heat alone

  8. Tests of equal effect per fraction in microcolony assays of survival after fractionated irradiations

    H.D Thames, Jr. and H.R. Withers propose a test of an equal effect per fraction in microcolony assays after fractionated radiation, in which the total effect is measured by counting microcolonies derived from surviving cells in a tissue. The factors considered to influence the cytocidal effect per fraction are incomplete repair, repopulation, and synchrony. The statistics used in the method are criticized and conditions are given under which the test should not be used. An alternative method of testing for an equal effect per fraction is proposed. The pros and cons of each test are discussed and compared using some mouse jejunal crypt cell survival data

  9. Fraction of energy absorbed from β-emitting particles in the rat lung

    Forty-four male Fischer-344 rats were exposed, nose only, to a relatively insoluble aerosol of 144Ce-labeled fused aluminosilicate particles. Fractional β energy absorption was measured 7 to 9 days after exposure for 28 rats (ages 12 to 25 weeks and body weights of 183 to 337 g); lung burdens were 13 to 82 nCi. An additional group of 16 rats was exposed when 12 weeks old and maintained for 6 months prior to analysis; body weights and lung burdens 6 months after exposure ranged from 276 to 368 g and 16 to 46 nCi, respectively. Lungs were carefully removed, inflated, and frozen by immersion in liquid nitrogen. The energy spectrum from each lung was measured in a 4π β spectrometer, keeping the lung frozen throughout this procedure. Over the range of lung sizes in this study (0.88 to 1.66 g) the mean fractional energy absorption and standard deviation were 0.23 +- 0.078, respectively. Results agreed well with theory, indicating that calculated values for fractional energy absorption in the lung can be used for a range of lung sizes and β energies. Calculated values for fractional energy absorption as a function of β energy are included for several lung sizes between 0.5 and 10 g

  10. Geant4-based comprehensive study of the absorbed fraction for electrons and gamma-photons using various geometrical models and biological tissues

    Rahman Ziaur

    2013-01-01

    Full Text Available The Geant4-based comprehensive model has been developed to predict absorbed fraction values for both electrons and gamma photons in spherical, ellipsoidal, and cylindrical geometries. Simulations have been carried out for water, ICRP soft-, brain-, lung-, and ICRU bone tissue for electrons in 0.1 MeV-4 MeV and g-photons in the 0.02 MeV-2.75 MeV energy range. Consistent with experimental observations, the Geant4-simulated values of absorbed fractions show a decreasing trend with an increase in radiation energy. Compared with NIST XCOM and ICRU data, the Geant4-based simulated values of the absorbed fraction remain within a 4.2% and 1.6% deviation, respectively. For electrons and g-photons, the relative difference between the Geant4-based comprehensive model predictions and those of Stabin and Konijnenberg's re-evaluation remains within a 6.8% and 7.4% range, respectively. Ellipsoidal and cylindrical models show 4.9% and 10.1% higher respective values of absorbed dose fractions relative to the spherical model. Target volume dependence of the absorbed fraction values has been found to follow a logical behavior for electrons and Belehradek's equation for g-photons. Gamma-ray absorbed fraction values have been found to be sensitive to the material composition of targets, especially at low energies, while for elections, they remain insensitive to them.

  11. Influence of high absorbed irradiation doses on conversion of CO2-H2S mixtures

    It was investigated the CO2-H2S mixture radiolysis at large absorbed irradiation doses. The observed high yield of final products in this system (Gpr.≥10.0) gives the possibility to consider the radiolytic hydrogen sulphide decomposition as one of the variants of purification of hydrogen sulphide containing residues of natural gas with a simultaneous production of sulphur and synthesis-gas (CO2). It has been show that at dose MGy∼16 % of initial product convert into synthesis-gas and sulfur. The mechanism of radiolytic conversion is discussed and the observed yield of hydrogen made G0(H2)=11.0±0.8 that considerably excesses G0(H2) at radiolysis of pure H2S(G0(H2)=7.5±0.5). Accumulation of carbon monoxide is described with 5 % accuracy with parabola of the second order: [CO] (-0.00082+0.359D-0.0013D2)·1019 mol/cm3 the initial yield of CO production for the given mixture is equal 3.59 which is G0(CO) = 4.5 in recalculation upon pure carbon dioxide. It has been established that the radiolytic reprocessing of acidic components of natural gas (CO2, H2S) gives the possibility to product sulphur and synthesis gas with yield to 30 vol.% (D=10 MGy), and the opportunity of simultaneous decision of ecological problems

  12. Development Manufacturing Method of Highly Functional Kapok Fiber Absorbent Using Irradiation

    Chung, Byung Yeoup; Kim, Jae Sung; Nho, Young Chang; Kang, Phil Hyun; Baek, Myung Hwa

    2006-01-15

    The hydrophobic characteristic of kapok fibers was changed to hydrophilic property after NaClO2, treatments which is able to break all phenolic units especially lignin. After NaClO2 treatment, NaIO4, applied to kapok fibers for opening hexagonal polysaccharide structure, this step led to produce carbonyl groups(>C=O) on kapok fibers. In the final step, NaClO2, treatments were performed again to provide carboxyl groups(-COOH) on kapok fibers. In addition, kapok fibers after all chemical treatments were retained hollow structure which was observed by scanning electron microscopy(SEM). Kapok fibers which were obtained after chemical treatments would be a good heavy metal absorbent when these fibers applied less than in 10 mg/L standard solution. Moreover, these fibers were not detached heavy metals even added physical forces and used kapok fibers are able to reuse after detached heavy metals under pH 2-3. The degree of grafting increased as the irradiation dose increased, and are in the range 32% to 250% when the concentration of glycidyl methacrylate monomer was 50 vol. %. Based on this result, various functional groups are possible to be attached on kapok fibers used by radiation grafting technique.

  13. Treatment of displaced radial head fractures by internal fixation with absorbable pins

    HOU Zhen-hai; ZHOU Ji-hong; SHI Jian-guo; SHI Yi-bin; XIA Jun-jie; YAO Jun

    2006-01-01

    Objective: To study the effect of internal fixation with absorbable pins on treatment of displaced radial head fractures.Methods: From May 1999 to May 2004, 16 patients with displaced radial head fractures (Mason types Ⅱ and Ⅲ) were treated with internal fixation by absorbable pins.The duration of follow-up averaged 22.6 months (12-58 months). The outcome was assessed on the basis of elbow motion, radiographic findings and the functional rating score delineated by Broberg and Morrey.Results: All fractures healed within 10 months without avascular necrosis of radial head. The mean elbow flexion loss was 15°(0°-35°), and pronation and supination decreased by 10° (0°-30°) on average compared with those of the contralateral elbow. Five patients had an excellent result, 6 a good result, and 3 a fair result according to the criteria of Borberg and Morrey.Conclusions: Internal fixation with absorbable pins is an effective method in treating displaced radial head fractures. It can maintain the biomechanical stability of forearm, improve the elbow function and avoid second operation.

  14. Stimulation of hematopoietic stem cells by interferon inducer in nonhuman primates receiving fractionated total body irradiation

    Interferon response and hematopoietic stem cells (spleen colony forming units-CFU-S) were studied in rhesus monkeys subjected to fractionated total body irradiation (FTBI). An interferon inducer, a nuclease resistant complex of polyinosinic-polycytidylic acid with poly-L-lysine and carboxmethylcellulose[-poly(ICLC)] was used. Poly(ICLC) at 3.75 mg/m2 was given I.V. to 7 monkeys, 5 of which, starting 24 hours later, received 50 rad of 4 MV X rays twice a week for 2.5 weeks (total of 250 rad). Another group of 4 monkeys received FTBI only. Although the initial interferon response was similar in both groups treated with poly(ICLC)-800 international units (IU), the animals receiving FTBI showed reduced interferon levels after 100 rad. These animals, however, did not develop the hyporesponsiveness to subsequent poly(ICLC) injections that was observed in non-irradiated monkeys. Stabile interferon response (30-100 IU) in the FTBI group paralleled the prolonged persistence of the drug in their serum. Bone marrow (BM) aspirates from animals receiving FTBI and poly(ICLC) contained more CFU-S per 106 nucleated cells than those treated with poly(ICLC) alone or FTBI alone. FTBI with and without poly(ICLC) led to thrombocytopenia and leukopenia. Lower white blood cell (WBC) count was found in irradiated animals treated with poly(ICLC). Partial alopecia was observed in animals receiving poly(ICLC). Two animals--one in the poly(ICLC) and FTBI group and the other receiving FTBI alone, died with thrombocytopenia and leukopenia

  15. Stimulation of hematopoietic stem cells by interferon inducer in nonhuman primates receiving fractionated total body irradiation

    Lvovsky, E.A. (George Washington Univ. Medical Center, Washington, DC); Levine, P.H.; Bengali, Z.; Leiseca, S.A.; Cicmanec, J.L.; Robinson, J.E.; Bautro, N.; Levy, H.B.; Scott, R.M.

    1982-10-01

    Interferon response and hematopoietic stem cells (spleen colony forming units--CFU-S) were studied in rhesus monkeys subjected to fractionated total body irradiation (FTBI). An interferon inducer, a nuclease resistant complex of polyinosinic-polycytidylic acid with poly-L-lysine and carboxmethylcellulose(-poly(ICLC)) was used. Poly(ICLC) at 3.75 mg/m/sup 2/ was given I.V. to 7 monkeys, 5 of which, starting 24 hours later, received 50 rad of 4 MV X rays twice a week at 2.5 weeks (total of 250 rad). Another group of 4 monkeys received FTBI only. Although the initial interferon response was similar in both groups treated wih poly(ICLC)--800 international units (IU), the animals that receiving FTBI showed reduced interferon levels after 100 rad. These animals, however, did not develop the hyporesponsiveness to subsequent poly(ICLC) injections that was observed in non-irradiated monkeys. Stabile interferon response (30-100 IU) in the FTBI group paralleled the prolonged persistence of the drug in their serum. Bone marrow (BM) aspirates from animals receiving FTBI and poly(ICLC) contained more CFU-S per 10/sup 6/ nucleated cells than those treated with poly(ICLC) along or FTBI with and without poly(ICLC) lead to thrombocytopenia and leukopenia. Lower white blood cell (WBC) count was found in irradiated animals treated with poly(ICLC). Partial alopecia was observed in animals receiving poly(ICLC). Two animals--one in the poly(ICLC) and FTBI group and the other receiving FTBI along, died with thrombocytopenia and leukopenia.

  16. Histological examination of the effect of differently fractionated irradiations in rat and mouse organs. Pt. 3

    The spleen of rats was irradiated with 50 Gy dose local X-rays in two different fractionation rhythms, i.e. twice a week given high and daily applied lower fractions of radiation. According to the results of 3H-thymidine autoradiography made after the last irradiation 24 hours later both in the white and the red pulp the labelling index was less on the effect of twice in a week applied high radiation fractions than in case of daily given lower fractions. This indicate in correlation with the results of earlier analogous histological experiments that the damaging effect of rarely given higher fractions of radiation in the spleen is especially obvious. (orig.)

  17. Investigation of the bystander effect in MRC5 cells after acute and fractionated irradiation in vitro

    Shokouhozaman Soleymanifard

    2014-01-01

    Full Text Available Radiation-induced bystander effect (RIBE has been defined as radiation responses observed in nonirradiated cells. It has been the focus of investigators worldwide due to the deleterious effects it induces in nonirradiated cells. The present study was performed to investigate whether acute or fractionated irradiation will evoke a differential bystander response in MRC5 cells. A normal human cell line (MRC5, and a human lung tumor cell line (QU-DB were exposed to 0, 1, 2, and 4Gy of single acute or fractionated irradiation of equal fractions with a gap of 6 h. The MRC5 cells were supplemented with the media of irradiated cells and their micronucleus frequency was determined. The micronucleus frequency after single and fractionated irradiation did not vary significantly in the MRC5 cells conditioned with autologous or QU-DB cell-irradiated media, except for 4Gy where the frequency of micronucleated cells was lower in those MRC5 cells cultured in the media of QU-DB-exposed with a single dose of 4Gy. Our study demonstrates that the radiation-induced bystander effect was almost similar after single acute and fractionated exposure in MRC5 cells.

  18. Quantitative changes of metabolic and bioenergetic parameters in experimental tumors during fractionated irradiation

    Purpose: Previous studies with rat rhabdomyosarcomas indicate that during fractionated irradiation profound alterations of the tumor microvasculature and the oxygenation status occur when the total dose exceeds 45 Gy. At this dose a destruction which included all structures of the vessels and a significant worsening in tumor oxygenation were found. The aim of the present study was to analyze whether these effects of fractionated irradiation on the microvasculature and on tumor oxygenation also induce changes in the bioenergetic and metabolic status in the tumors during radiation treatment. Methods and Materials: R1H rhabdomyosarcomas of the rat implanted into the flank were irradiated with 60Co-γ-rays using 5 fractions of 3 Gy per week over 5 weeks. During this irradiation schedule, tumors were investigated each week for the microregional distributions of glucose, lactate, and ATP concentrations. For this, tumors were rapidly excised, shock-frozen and quantitative bioluminescence measurements were performed on tumor tissue sections. Results: ATP concentrations remained unchanged during fractionated irradiation up to a total dose of 45 Gy. Above this dose, a significant decrease in ATP levels was observed. Lactate concentrations changed only slightly during irradiation whereas glucose levels increased continuously over the whole irradiation period. Conclusions: During fractionated irradiation of R1H tumors with a total dose of 75 Gy, the bioenergetic and metabolic status of the tumors changed considerably. This became most obvious once a dose of 45 Gy had been achieved. The severe energy depletion and worsening of tumor oxygenation might be the result of destruction of tumor blood vessels as has been described previously in the same tumor model. The modification of the tumor micromilieu appears to be an important parameter in the responsiveness of tumor cells to radiation and for local tumor control

  19. Clinical and immunologic effects of fractionated total lymphoid irradiation in refractory rheumatoid arthritis

    Ten patients with refractory rheumatoid arthritis were given 3000 rad of fractionated total lymphoid irradiation in an uncontrolled therapeutic trial. Total lymphoid irradiation was associated with objective evidence of considerable clinical improvement in eight patients and with reduced blood lymphocyte counts in all 10. On completion of irradiation, there was an abrogation of lymphocyte reactivity in vitro in the patients with clinical responses, but abnormal antibody activities characteristic of rheumatoid arthritis and normal components of humoral immunity were not suppressed. Partial recrudescence of arthritis occurred shortly after a year after the completion of irradiation and was paralleled by a restitution of lymphocyte concentrations and responsiveness to mitogens to levels similar to those observed before irradiation. These data provide further evidence of T-cell involvement in the pathogenesis of rheumatoid arthritis and demonstrate that total lymphoid irradiation can induce temporary relief, but they do not ascertain whether the natural history of this disease was altered

  20. Dietary enhancement of intestinal radioresistance during fractionated irradiation

    Rats fed laboratory chow or elemental diet 3 were given fractions of 240 rads of 60Co γ radiation abdominally (1200 rads/week) until all animals had died. Changes in appetite, body weight, and mortality were monitored as a function of the cumulative dose received. More radiation was needed in the diet-fed group to achieve both 0 and 100% mortality, a difference of 37% at the mean lethal dose level. Both groups developed similar progressive anorexia but the diet-fed animals lost weight more slowly. Data indicate that basic intestinal radioresistance is enhanced by feeding the elemental diet

  1. Enhancement of plant growth activity of irradiated chitosan by molecular weight fractionation

    The chitosan products irradiated at 25-200 kGy in 10% solution showed a positive effect on the growth of barley, while the unirradiated chitosan inhibited the growth of this plant. The 100 kGy irradiated chitosan product with average molecular weight (Mw) approx. 16 kDa was found as optimal to plant growth activity. Separation of the degraded samples was performed using ultrafiltration membranes and was found that the fraction F2 with Mw in range of 1 - 3 kDa not only showed a remarkable effect on the growth of barley and soybean, but also significantly increased the activity of phytoalexin enzymes, namely phenylalanine ammonia lyase (87%) and chitinase (186%). This fraction also increased 15.8% seed yield of soybean after three month cultivation. The results suggested that the irradiated chitosan fraction F2 with Mw in range of 1 - 3 kDa was a trigger for plant growth activity. (author)

  2. Histopathological changes in the irradiated normal organs of guinea pigs with conventional fractionation and hyperfractionation

    Guinea pigs were divided into groups according to four irradiation schedules : 2 Gy/3 Gy x 1/day, five fractions/week, total 80 Gy/81 Gy (A/C group) and 1.0 Gy/1.5 Gy x 2/day, ten fractions/week, total 80 Gy/81 Gy (B/D group). The A group and the C group pathologically caused severe damage in the kidney six and three months after irradiation, respectively. In the B group pathological analysis suggested that only slight-to-moderate changes were occurred in the Bowman's capsule. The D group caused slight damage in the kidney six months after irradiation. Hyperfractionation (B/D group) used in this protocol can clearly reduce radiation damage in the kidney of guinea pigs as compared with conventional fractionation (A/C group). (author)

  3. The clinical research on fractionated irradiation treatment with X knife in patients of PD

    Objective: To explore X knife treatment methods and to seek a new effective way for PD therapy. Methods: Sixteen patients of PD were treated by performing VIM with 2 times of X knife fractionated irradiation (interval, 24 h) to a total dose of 140 Gy, and 8 patients of PD were treated by performing VIM with 3 times of X knife fractionated irradiation (interval, 24 h) to a total of dose of 165 Gy. Results: During 3-24 months follow-up after X knife treatment, tremor was stopped in 19 patients and was relived significantly in 5 patients. Rigidity and bradykinesia of PD were relieved slightly. No complications were observed. Conclusion: To perform VIM with X knife fractionated irradiation can be safely and effectively used to treat PD. The tremor of PD can be relieved slightly

  4. Role of Rad52 in fractionated irradiation induced signaling in A549 lung adenocarcinoma cells

    Ghosh, Somnath, E-mail: ghosh.barc@gmail.com [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Krishna, Malini, E-mail: malinik00@gmail.com [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2012-01-03

    The effect of fractionated doses of {gamma}-irradiation (2 Gy per fraction over 5 days), as delivered in cancer radiotherapy, was compared with acute doses of 10 and 2 Gy, in A549 cells. A549 cells were found to be relatively more radioresistant if the 10 Gy dose was delivered as a fractionated regimen. Microarray analysis showed upregulation of DNA repair and cell cycle arrest genes in the cells exposed to fractionated irradiation. There was intense activation of DNA repair pathway-associated genes (DNA-PK, ATM, Rad52, MLH1 and BRCA1), efficient DNA repair and phospho-p53 was found to be translocated to the nucleus of A549 cells exposed to fractionated irradiation. MCF-7 cells responded differently in fractionated regimen. Silencing of the Rad52 gene in fractionated group of A549 cells made the cells radiosensitive. The above result indicated increased radioresistance in A549 cells due to the activation of Rad52 gene.

  5. Role of Rad52 in fractionated irradiation induced signaling in A549 lung adenocarcinoma cells.

    Ghosh, Somnath; Krishna, Malini

    2012-01-01

    The effect of fractionated doses of γ-irradiation (2Gy per fraction over 5 days), as delivered in cancer radiotherapy, was compared with acute doses of 10 and 2Gy, in A549 cells. A549 cells were found to be relatively more radioresistant if the 10Gy dose was delivered as a fractionated regimen. Microarray analysis showed upregulation of DNA repair and cell cycle arrest genes in the cells exposed to fractionated irradiation. There was intense activation of DNA repair pathway-associated genes (DNA-PK, ATM, Rad52, MLH1 and BRCA1), efficient DNA repair and phospho-p53 was found to be translocated to the nucleus of A549 cells exposed to fractionated irradiation. MCF-7 cells responded differently in fractionated regimen. Silencing of the Rad52 gene in fractionated group of A549 cells made the cells radiosensitive. The above result indicated increased radioresistance in A549 cells due to the activation of Rad52 gene. PMID:22001234

  6. The studies of irradiation assisted stress corrosion cracking on reactor internals stainless steel under Xe irradiation

    Wang, Rong-shan [Suzhou Nuclear Power Research Institute, Suzhou, Jiangsu Province 215004 (China); Xu, Chao-liang, E-mail: xuchaoliang@cgnpc.com.cn [Suzhou Nuclear Power Research Institute, Suzhou, Jiangsu Province 215004 (China); Liu, Xiang-bing; Huang, Ping [Suzhou Nuclear Power Research Institute, Suzhou, Jiangsu Province 215004 (China); Chen, Yu [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Beijing 100049 (China)

    2015-02-15

    Specimens of Chinese domestic reactor internals stainless steel were irradiated with 6 MeV Xe ions for three peak displacement damage of 2, 7 and 15 dpa at room temperature. The slow strain rate tests (SSRT), grazing incidence X-ray diffraction (GIXRD) and nano-indentation tests were carried out to study the IASCC properties, phase transition and nano-hardness variations. The SSRT results indicate that the IASCC susceptibility increases with irradiation damage. Ion irradiation accelerates the stress corrosion cracking (SCC). A new ferrite phase diffraction peak of α(1 1 0) after irradiated to 7 dpa and another two α phase of α(2 0 0) and α(2 1 1) after irradiated to 15 dpa were observed by GIXRD, which may be due to localized deformation. A similar trend of irradiation hardening and IASCC susceptibility was observed, which suggests an essential connection between them.

  7. Curcumin Stimulates the Antioxidant Mechanisms in Mouse Skin Exposed to Fractionated γ-Irradiation.

    Jagetia, Ganesh Chandra; Rajanikant, Golgod Krishnamurthy

    2015-01-01

    Fractionated irradiation is one of the important radiotherapy regimens to treat different types of neoplasia. Despite of the immense therapeutic gains accrued by delivering fractionated irradiation to tumors, the radiation burden on skin increases significantly. Low doses of irradiation to skin adversely affect its molecular and metabolic status. The use of antioxidant/s may help to alleviate the radiation-induced changes in the skin and allow delivering a higher dose of radiation to attain better therapeutic gains. Curcumin is an antioxidant and a free radical scavenging dietary supplement, commonly used as a flavoring agent in curries. Therefore, the effect of 100 mg/kg body weight curcumin was studied on the antioxidant status of mice skin exposed to a total dose of 10, 20 and 40 Gy γ-radiation below the rib cage delivered as a single fraction of 2 Gy per day for 5, 10 or 20 days. Skin biopsies from both the curcumin treated or untreated irradiated groups were collected for the biochemical estimations at various post-irradiation times. The irradiation of animals caused a dose dependent decline in the glutathione concentration, glutathione peroxidase, and superoxide dismutase activities and increased the lipid peroxidation in the irradiated skin. Curcumin treatment before irradiation resulted in a significant rise in the glutathione concentration and activities of both the glutathione peroxidase and superoxide dismutase enzymes in mouse skin, whereas lipid peroxidation declined significantly. The present study indicates that curcumin treatment increased the antioxidant status of mouse exposed to different doses of fractionated γ-radiation. PMID:26785336

  8. Curcumin Stimulates the Antioxidant Mechanisms in Mouse Skin Exposed to Fractionated γ-Irradiation

    Ganesh Chandra Jagetia

    2015-01-01

    Full Text Available Fractionated irradiation is one of the important radiotherapy regimens to treat different types of neoplasia. Despite of the immense therapeutic gains accrued by delivering fractionated irradiation to tumors, the radiation burden on skin increases significantly. Low doses of irradiation to skin adversely affect its molecular and metabolic status. The use of antioxidant/s may help to alleviate the radiation-induced changes in the skin and allow delivering a higher dose of radiation to attain better therapeutic gains. Curcumin is an antioxidant and a free radical scavenging dietary supplement, commonly used as a flavoring agent in curries. Therefore, the effect of 100 mg/kg body weight curcumin was studied on the antioxidant status of mice skin exposed to a total dose of 10, 20 and 40 Gy γ-radiation below the rib cage delivered as a single fraction of 2 Gy per day for 5, 10 or 20 days. Skin biopsies from both the curcumin treated or untreated irradiated groups were collected for the biochemical estimations at various post-irradiation times. The irradiation of animals caused a dose dependent decline in the glutathione concentration, glutathione peroxidase, and superoxide dismutase activities and increased the lipid peroxidation in the irradiated skin. Curcumin treatment before irradiation resulted in a significant rise in the glutathione concentration and activities of both the glutathione peroxidase and superoxide dismutase enzymes in mouse skin, whereas lipid peroxidation declined significantly. The present study indicates that curcumin treatment increased the antioxidant status of mouse exposed to different doses of fractionated γ-radiation.

  9. Effect of absorbed dose and storage length on electron paramagnetic resonance (EPR) signal strength in irradiated alfalfa seeds

    2006-01-01

    A kind of alfalfa seeds was irradiated by 1, 2, 3, 4 and 5 kGy at a dose rate of 6.288 kGy. h-1 in a self-shielded irradiator of 137Cs gamma rays. The EPR spectra, which were measured subsequently between 0.3401and 0.3501 T, showed that there was a direct proportional relationship between the EPR signal strength of free radicals produced by gamma irradiation in the alfalfa seeds and absorbed dose. The first derivative EPR spectra of the alfalfa seeds were very clear and easy to identify. However, the EPR signal strength of the peak-to-peak amplitude decreased rapidly and most of them decayed beyond 50% within 3 days after the seeds were irradiated. It tended to stabilize after half a month since the seeds were irradiated. The differences of the EPR signal strength between the irradiated and unirradiated alfalfa seeds still remained. All seeds were stored at ambient temperature for more than 3months. Therefore, using EPR spectrometry technique to measure free radicals in alfalfa seeds as a means to determine whether the seeds have been irradiated or not is feasible, relatively fast and simple.

  10. Effect of absorbed dose and storage length on electron paramagnetic resonance (EPR) signal strength in irradiated alfalfa seeds

    A kind of alfalfa seeds was irradiated by 1, 2, 3, 4 and 5 kGy at a dose rate of 6.288 kGy·h-1 in a self-shielded irradiator of 137Cs gamma rays. The EPR spectra, which were measured subsequently between 0.3401 and 0.3501 T, showed that there was a direct proportional relationship between the EPR signal strength of free radicals produced by gamma irradiation in the alfalfa seeds and absorbed dose. The first derivative EPR spectra of the alfalfa seeds were very clear and easy to identify. However, the EPR signal strength of the peak-to-peak amplitude decreased rapidly and most of them decayed beyond 50% within 3 days after the seeds were irradiated. It tended to stabilize after half a month since the seeds were irradiated. the differences of the EPR signal strength between the irradiated and unirradiated alfalfa seeds still remained. All seeds were stored at ambient temperature for more than 3 months. Therefore, using EPR spectrometry technique to measure free radicals in alfalfa seeds as a means to determine whether the seeds have been irradiated or not is feasible, relatively fast and simple. (authors)

  11. The effect of cis-diamminedichloroplatinum (II) on radiation damage in mouse rectum after fractionated irradiation

    Dewit, L.; Oussoren, Y.; Bartelink, H. (Nederlands Kanker Inst. ' Antoni van Leeuwenhoekhuis' , Amsterdam (Netherlands)); Thames, H.D. (Anderson (M.D.) Hospital and Tumor Inst., Houston, TX (USA))

    1989-10-01

    The influence of cis-diamminedichloroplatinum (II) (c-DDP) on radiation injury in the rectum of ice was investigated after single dose and fractionated irradiation. Mice were exposed to single doses, or 2, 4 or 8 fractions of X-rays given daily (or twice a day for the 8 fractions) with or without 8 mg/kg of c-DDP. The incidence of rectal stenosis and of anal discharge were scored and a direct analysis of the data for linear-quadratic dose-dependence of damage was performed with correction for censoring. For each endpoint, c-DDP did not significantly change the dose-response curves after fractionated irradiation. Subtile modifications in the coefficients of the linear-quadratic relationship were observed. The drug appeared to increase the {alpha} term by a factor of 2.3 and the {beta} term by a factor of 1.5, but the differences did not reach statistical significance. For the rectal stenosis endpoint, the {alpha}/{beta} was 4.4 Gy after irradiation alone and 6.9 Gy after combination treatment. Again the differences were not significant. These data suggest that c-DDP did not reduce the repair capacity in the mouse rectum during fractionated irradiation. Combined modality therapy with c-DDP and radiation would therefore not be expected to cause an increas in late damage in the large bowel. (author). 23 refs.; 2 figs.; 1 tab.

  12. EFFECT OF IRRADIATION TEMPERATURE ON GENERAL EQUATION OF SOL FRACTION-DOSE RELATIONSHIP FOR FLUOROPOLYMERS

    ZHANG Wanxi; XU Jun

    1992-01-01

    In this paper, the effect of irradiation temperature on sol fraction-dose relationship of fluoropolymers was studied. It was found that the increasing of irradiation temperature can result in the decreasing of β value of fluoropolymer , which increases the crosslinking probability of fluoropolymer. The relationship between crosslinking parameter β and irradiation temperature (Ti)of fluoropolymer is established as follows:β=2.2 × 10-3Tg +4×10-4 (Tg-Ti )+0.206.β values of some fluoropolymers calculated from the above expression are in agreement with the experimental values.

  13. Fractionated irradiation combined with carbogen breathing and nicotinamide of two human glioblastomas grafted in nude mice

    SUN, Lin-Quan; Buchegger, Franz; COUCKE, Philippe; MIRIMANOFF

    2001-01-01

    This study addressed the potential radiosensitizing effect of nicotinamide and/or carbogen on human glioblastoma xenografts in nude mice. U-87MG and LN-Z308 tumors were irradiated with either 20 fractions over 12 days or 5 fractions over 5 days in air-breathing mice, mice injected with nicotinamide, mice breathing carbogen, or mice receiving nicotinamide plus carbogen. The responses to treatment were assessed using local control and moist desquamation. In U-87MG tumors, the enhancement ratios...

  14. Fractional Absorption of Active Absorbable Algal Calcium (AAACa and Calcium Carbonate Measured by a Dual Stable-Isotope Method

    Steven A. Abrams

    2010-07-01

    Full Text Available With the use of stable isotopes, this study aimed to compare the bioavailability of active absorbable algal calcium (AAACa, obtained from oyster shell powder heated to a high temperature, with an additional heated seaweed component (Heated Algal Ingredient, HAI, with that of calcium carbonate. In 10 postmenopausal women volunteers aged 59 to 77 years (mean ± S.D., 67 ± 5.3, the fractional calcium absorption of AAACa and CaCO3 was measured by a dual stable isotope method. 44Ca-enriched CaCO3 and AAACa were administered in all subjects one month apart. After a fixed-menu breakfast and pre-test urine collection (Urine 0, 42Ca-enriched CaCl2 was intravenously injected, followed by oral administration of 44Ca-enriched CaCO3 without carrier 15 minutes later, and complete urine collection for the next 24 hours (Urine 24. The fractional calcium absorption was calculated as the ratio of Augmentation of 44Ca from Urine 0 to Urine 24/ augmentation of 42Ca from Urine 0 to Urine 24. Differences and changes of 44Ca and 42Ca were corrected by comparing each with 43Ca. Fractional absorption of AAACa (mean ± S.D., 23.1 ± 6.4, was distinctly and significantly higher than that of CaCO3 (14.7 ± 6.4; p = 0.0060 by paired t-test. The mean fractional absorption was approximately 1.57-times higher for AAACa than for CaCO3. The serum 25(OH vitamin D level was low (mean ± S.D., 14.2 ± 4.95 ng/ml, as is common in this age group in Japan. Among the parameters of the bone and mineral metabolism measured, none displayed a significant correlation with the fractional absorption of CaCO3 and AAACa. Higher fractional absorption of AAACa compared with CaCO3 supports previous reports on the more beneficial effect of AAACa than CaCO3 for osteoporosis.

  15. Evaluation of absorbed dose in irradiated sugar-containing plant material (peony roots) by an ESR method

    Yamaoki, Rumi; Kimura, Shojiro; Ohta, Masatoshi

    2015-12-01

    The relationship between electron spin resonance (ESR) signal intensity of irradiated plant materials and sugar content was investigated by spectral analysis using peony roots. A weak background signal near g=2.005 was observed in the roots. After a 10 kGy irradiation, the ESR line broadened and the intensity increased, and the spectral characteristics were similar to a typical spectrum of irradiated food containing crystalline sugars. The free radical concentration was nearly stable 30 days after irradiation. The spectrum of peony root 30 days after irradiation was simulated using the summation of the intensities of six assumed components: radical signals derived from (a) sucrose, (b) glucose, (c) fructose, (d) cellulose, (e) the background signal near g=2.005 and (f) unidentified component. The simulated spectra using the six components were in agreement with the observed sample spectra. The intensity of sucrose radical signal in irradiated samples increased proportionally up to 20 kGy. In addition, the intensity of sucrose radical signals was strongly correlated with the sucrose contents of the samples. The results showed that the radiation sensitivity of sucrose in peony roots was influenced little by other plant constituents. There was also a good correlation between the total area of the spectra and the sucrose content, because the sucrose content was higher than that of other sugars in the samples. In peony roots, estimation of the absorbed dose from the ESR signal intensity may be possible by a calibration method based on the sucrose content.

  16. Self-shielding and burn-out effects in the irradiation of strongly-neutron-absorbing material

    Self-shielding and burn-out effects are discussed in the evaluation of radioisotopes formed by neutron irradiation of a strongly-neutron-absorbing material. A method of the evaluation of such effects is developed both for thermal and epithermal neutrons. Gadolinium oxide uniformly mixed with graphite powder was irradiated by reactor-neutrons together with pieces of a Co-Al alloy wire (the content of Co being 0.475%) as the neutron flux monitor. The configuration of the samples and flux monitors in each of two irradiations is illustrated. The yields of activities produced in the irradiated samples were determined by the γ-spectrometry with a Ge(Li) detector of a relative detection efficiency of 8%. Activities at the end of irradiation were estimated by corrections due to pile-up, self-absorption, detection efficiency, branching ratio, and decay of the activity. Results of the calculation are discussed in comparison with the observed yields of 153Gd, 160Tb, and 161Tb for the case of neutron irradiation of disc-shaped targets of gadolinium oxide. (T.G.)

  17. In Vitro and In Vivo Radiosensitizing Effect of Valproic Acid on Fractionated Irradiation

    Chie, Eui Kyu; Shin, Jin Hee; Kim, Jin Ho; Kim, Hak Jae; Kim, In Ah; Kim, Il Han

    2014-01-01

    Purpose This study was conducted in order to validate the radiosensitization effect of valproic acid, a biologically available histone deacetylase inhibitor, for fractionated radiation. Materials and Methods Radiosensitization effect of valproic acid was tested for the A549 cell line and U87MG cell line in vitro. Fractionated irradiation of 12 Gy in four fractions was administered on D2-5 with valproic acid, 150 mg/Kg, ip, bid for six consecutive days (D1-6) to A549 and U87MG tumors implanted...

  18. Effects of single dose and fractionated irradiation on brain aggregation culture

    Foetal mouse brain cells were grown in vitro. One Gy of X-irradiation was given as a single dose on culture day 2 (corresponding to embryonic day 17 in vivo) or in daily fractions (4 x 0.25 Gy), starting on day 2 in culture. The growth (size) and biochemical differentiation of the aggregates were studied up to day 40 in culture. Aggregates given a single dose (1 Gy) were smaller with lower protein and DNA amount than controls up to day 30-40 in culture. When the dose was fractionated, a partial recovery occurred by day 20, and values returned to control levels by day 30-40. The specific activity of acetylcholine-esterase (AChE) was significantly higher after 10 to 20 days, in the irradiated (1 Gy) aggregates. In fractionated irradiated aggregates, only the specific activity of AChE was increased. This effect was only evident after 10 days in culture. Single irradiation induced, after 10 days in culture, an increase of nerve growth factor (NGF), however after 30 days the NGF amount decreased below control level. A single dose of irradiation produced more permanent changes in the amounts of DNA and protein and in the size and neurochemical activities of cells. (author)

  19. Response of human lymphocyte chromosomes to fractionated neutron irradiation in vitro

    Sevan' kaev, A.V.; Nasonova, V.A.; Golovinova, G.I. (Akademiya Meditsinskikh Nauk SSSR, Obninsk. Nauchno-Issledovatel' skij Inst. Meditsinskoj Radiologii)

    A comparative study was made of the yield of chromosome aberrations in a human lymphocyte culture after a single and fractionated exposure to neutron radiation at the beginning of the G/sub 1/ phase and during the S phase of the mitotic cycle. It was shown that the degree of the chromosome affection in both phases does not depend upon the irradiation schedules.

  20. Radiobiological effect of abdominal X-ray hypo-fraction irradiation on Wistar rats liver

    Peng Qi; Yongheng An; Hongsheng Yu; Xinjia He

    2012-01-01

    Objective: The aim of our study was to investigate the impact of abdominal hypo-fraction irradiation on liver dam-age in rats so as to provide a reference for its clinical application. Methods: A total of 100 Wistar rats were equally randomized to five groups as control, 4 Gy, 6 Gy, 8 Gy and 12 Gy group, and the corresponding fractionated doses were offered. Liver functions were examined at the 2nd, 4th, 6th, 8th and 10th week after irradiation. Morphological changes were observed by HE staining. Expressions of Bcl-2 and Bax were examined by immunohistochemical technique. Results: In all irradiation groups, hepatocellular swell, degeneration, necrosis and even hepatic fibrosis could be seen. The differences of the liver coef-ficient, Glutamyl pyruvic transaminase (GPT), Glutamyl oxaloacetic transaminase (GOT) were significant among the groups and different time points (F = 11.833–781.972, F = 20.857–264.692, P < 0.001). Expressions of Bcl-2 and Bax were signifi-cantly different between each group (F = 211.607, 116.577; P < 0. 001), and between each time point (F = 54.083, 68.749; P < 0. 001). Conclusion: Compare with conventional fraction, abdominal hypo-fraction irradiation may cause radiation damage to rat liver, being dose-and-time dependent. Up-regulation of activating apoptosis protein Bax and down-regulation of inhibiting apoptosis protein Bcl-2 may involve in the process.

  1. Annual rate of hearing loss falls after fractionated stereotactic irradiation for vestibular schwannoma

    Purpose: The rate of hearing loss in a population before and after irradiation was investigated to determine the effect of irradiation on hearing impairment. Methods and materials: In 72 patients with vestibular schwannoma who received fractionated stereotactic irradiation from 1992 to 1999, 21 had had their hearing levels examined 3 months or more before the treatment. The mean time between the initial examination and treatment was 18.6 months (range: 3-89 months), and the mean time between treatment and the last follow-up was 24.2 months (12-69 months). Thirty-six to 50 Gy in 20-25 fractions over 5 to 6 weeks was given using an X-ray beam from a linear accelerator. Pure tone average (PTA) was measured using the mean hearing level at five frequencies, and the annual rate of hearing loss was defined as [(hearing loss in PTA(dB))/(follow-up period (months)x12)]. Results: The actual cumulative curve of decrease in tumor size of 2 mm or more was 38.3% at 2 years and 80.0% at 3 years. The mean of hearing loss in PTA was 11.6±10.3 dB (-1 to 35 dB) from the initial examination to the start of irradiation and 11.9±14.4 dB (-14 to 37 dB) from the start of irradiation to the last follow-up. The mean annual rates of hearing loss before irradiation and in the 1st, 2nd, 3rd and 4th years after irradiation were, respectively, 18.6, 11.2, 6.2, 5.1, and 5.0 dB/year. The annual rates of hearing loss in the 2nd year (P=0.025) and 3rd year (P=0.018) were significantly slower than the rate before irradiation. Conclusions: The mean annual rate of hearing loss was higher before irradiation than after irradiation, and hearing loss slowed rather than accelerated after irradiation. Although hearing loss after the treatment was usually permanent, fractionated stereotactic irradiation was suggested to be effective to lower the rate of hearing loss

  2. Mathematical models and specific absorbed fractions of photon energy in the nonpregnant adult female and at the end of each trimester of pregnancy

    Stabin, M.G.; Watson, E.E.; Cristy, M.; Ryman, J.C.; Eckerman, K.F. [Oak Ridge National Lab., TN (United States); Davis, J.L. [Tennessee Univ., Chattanooga, TN (United States); Marshall, D. [Florida Univ., Gainesville, FL (United States). Dept. of Nuclear Engineering; Gehlen, M.K. [San Diego State Univ., CA (United States)

    1995-05-08

    Mathematical phantoms representing the adult female at three, six, and nine months of gestation are described. They are modifications of the 15-year-old male/adult female phantom (15-AF phantom) of Cristy and Eckerman (1987). The model of uterine contents includes the fetus, fetal skeleton, and placenta. The model is suitable for dose calculations for the fetus as a whole; individual organs within the fetus (other than the skeleton) are not modeled. A new model for the nonpregnant adult female is also described, comprising (1) the 15-AF phantom; (2) an adjustment to specific absorbed fractions for organ self-dose from photons to better match Reference Woman masses; and (3) computation of specific absorbed fractions with Reference Woman masses from ICRP Publication 23 for both penetrating and nonpenetrating radiations. Specific absorbed fractions for photons emitted from various source regions are tabulated for the new non;pregnant adult female model and the three pregnancy models.

  3. Effects of keratinocyte growth factor (palifermin) administration protocols on oral mucositis (mouse) induced by fractionated irradiation

    Background and purpose: Aim of this study was to assess the impact of the administration protocol of palifermin on amelioration of oral mucositis after fractionated irradiation. Materials and methods: Mouse tongue ulceration was analysed as the clinically relevant endpoint. Daily fractionated irradiation (5x3 Gy/week, days 0 to +4, +7 to +11, with a weekend gap on days +5 and +6) was followed by graded test doses on day +14, i.e. after a second weekend gap. Palifermin (5 mg/kg) was injected subcutaneously. In the first series of experiments, the effect of three daily injections (days -3, -2 and -1) was compared with a single administration either on day -2 or -1; all animals received a further injection on day +4. In the second series, a single or three injections were given in the weekend gap between fractionated irradiation (days +5 to +6), with an additional administration on day +11. In a final protocol, single weekly injections of palifermin were given either on days -3, +4 and +11, days +4, +11 and +18, or on days -3, +4, +11 and +18. Results: The ED50 (dose after which ulcer induction is expected in 50% of the mice) to single dose irradiation was 11.5±0.7 Gy. The ED50 for test irradiation after 10x3 Gy was 5.7±1.6 Gy. Palifermin administration before the start of fractionated irradiation and on day +4 increased the ED50 to 10-12 Gy, administration over the first weekend and on day +11 to 11-15 Gy. Administration over three consecutive weekends, starting on day -3 or day +4, increased the ED50 to 13.0±0.1 and 14.9±0.3 Gy. Single weekly KGF administrations over four weekends, including the weekend prior to and after completion of radiotherapy, showed no further increase in ED50. Conclusions: A single palifermin injection during the weekend gap before or during fractionated irradiation is as effective as three applications. Onset of the palifermin treatment during the first weekend gap between fractionated irradiation is more effective than during the

  4. Effect of roentgen, cyclotron neutron, or mixed neutron-photon fractionated irradiation of mice

    Mice were whole-body-irradiated with 5 fractions of roentgen rays in 5 days, 5 fractions of cycotron neutrons in 5 days, or with mixed neutron-photon fractionated radiation, in the sequence n-n-x-x-x or n-x-x-x-n. The LD50 sub(/) 4 day values were determined. Roentgen rays and neutrons interact in the additive manner in the mixed fractionation schemes: effective dose per fraction is as predicted from the roentgen ray-only and neutron-only experiments. This essentially agrees with HENDRY et coll. (1976). However, no trend was found towards a less-than-additive effect which was observed by those authors and has also been suggested in skin response to mixed schemes (NELSON et coll 1975). (author)

  5. Geant4-based comprehensive study of the absorbed fraction for electrons and gamma-photons using various geometrical models and biological tissues

    Rahman Ziaur; Rehman Shakeel Ur.; Mirza Sikander M.; Arshed Waheed; Mirza Nasir M.

    2013-01-01

    The Geant4-based comprehensive model has been developed to predict absorbed fraction values for both electrons and gamma photons in spherical, ellipsoidal, and cylindrical geometries. Simulations have been carried out for water, ICRP soft-, brain-, lung-, and ICRU bone tissue for electrons in 0.1 MeV-4 MeV and g-photons in the 0.02 MeV-2.75 MeV energy range. Consistent with experimental observations, the Geant4-simulated values of absorbed fractions show a ...

  6. Influence of post-harvest irradiation time and absorbed dose to potatoes and onions

    Post harvest losses of potatoes and onions were mainly due to sprouting and rotting. Irradiation dose of 50 Gy for onions and of 100 Gy for potatoes applied within the dormancy period effectively inhibited sprouting. In Vietnam conditions the optimal irradiation time after harvest is 3 - 6 weeks for potatoes, within 4 weeks for onions. Irradiated potatoes and onions stored under ambient conditions tend to be more spoiled in comparison with unirradiated ones.Irradiation caused a slight decrease of vitamin C content and an increase of reduced sugars and total sugars for potatoes and onions stored under room temperature. There are no changes in main nutritional properties of irradiated onions, no after-cooking discoloration in irradiated potatoes. (author). 8 refs, 4 tabs, 9 figs

  7. Estimating Solar Irradiation Absorbed by Photovoltaic Panels with Low Concentration Located in Craiova, Romania

    Ionel L. Alboteanu; Cornelia A. Bulucea; Sonia Degeratu

    2015-01-01

    Solar irradiation is one of the important parameters that should be taken into consideration for the design and utilization of a photovoltaic system. Usually, the input parameters of a photovoltaic system are solar irradiation, the ambient environment temperature and the wind speed, and as a consequence most photovoltaic systems are equipped with sensors for measuring these parameters. This paper presents several mathematical models for solar irradiation assessment. The starting point is repr...

  8. Optical properties of ion irradiated and annealed InGaAs/GaAs quantum wells and semiconductor saturable absorber mirrors

    Hakkarainen, T [Optoelectronics Research Centre, Tampere University of Technology, PO Box 692, FI-33101, Tampere (Finland); Pavelescu, E-M [Optoelectronics Research Centre, Tampere University of Technology, PO Box 692, FI-33101, Tampere (Finland); Arstila, K [Accelerator Laboratory, University of Helsinki, PO Box 43, FI-00014, Helsinki (Finland); Dhaka, V D S [Institute of Materials Chemistry, Tampere University of Technology, PO Box 541, FI-33101, Tampere (Finland); Hakulinen, T [Optoelectronics Research Centre, Tampere University of Technology, PO Box 692, FI-33101, Tampere (Finland); Herda, R [Optoelectronics Research Centre, Tampere University of Technology, PO Box 692, FI-33101, Tampere (Finland); Konttinen, J [Optoelectronics Research Centre, Tampere University of Technology, PO Box 692, FI-33101, Tampere (Finland); Tkachenko, N [Institute of Materials Chemistry, Tampere University of Technology, PO Box 541, FI-33101, Tampere (Finland); Lemmetyinen, H [Institute of Materials Chemistry, Tampere University of Technology, PO Box 541, FI-33101, Tampere (Finland); Keinonen, J [Accelerator Laboratory, University of Helsinki, PO Box 43, FI-00014, Helsinki (Finland); Pessa, M [Optoelectronics Research Centre, Tampere University of Technology, PO Box 692, FI-33101, Tampere (Finland)

    2005-04-07

    Optical properties of Ni{sup +} irradiated and thermally annealed InGaAs/GaAs multiple quantum wells and semiconductor saturable absorber mirrors (SESAMs) have been studied using photoluminescence (PL) and non-linear reflectivity measurements. Rapid decrease of PL intensity and lifetime with increasing irradiation dose was accompanied by undesirable degradation of the non-linear optical properties of SESAMs. However, some of the irradiation-created defects could be removed and the non-linear optical properties improved by rapid thermal annealing. The combination of ion irradiation and annealing provided a selective method for controlling the absorption recovery time of SESAMs while preserving the non-linear properties. Irradiation with 10{sup 12} cm{sup -2} of 6 MeV Ni{sup +} ions and 1 s annealing at 400 deg. C led to an absorption recovery time of {approx}1 ps while the modulation depth, the non-saturable losses and the saturation fluence were all close to their as-grown values.

  9. Changes in the fraction of total hypoxia and hypoxia subtypes in human squamous cell carcinomas upon fractionated irradiation: Evaluation using pattern recognition in microcirculatory supply units

    Background and purpose: Evaluate changes in total hypoxia and hypoxia subtypes in vital tumor tissue of human head and neck squamous cell carcinomas (hHNSCC) upon fractionated irradiation. Materials and methods: Xenograft tumors were generated from 5 hHNSCC cell lines (UT-SCC-15, FaDu, SAS, UT-SCC-5 and UT-SCC-14). Hypoxia subtypes were quantified in cryosections based on (immuno-)fluorescent marker distribution patterns of Hoechst 33342 (perfusion), pimonidazole (hypoxia) and CD31 (endothelium) in microcirculatory supply units (MCSUs). Tumors were irradiated with 5 or 10 fractions of 2 Gy, 5×/week. Results: Upon irradiation with 10 fractions, the overall fraction of hypoxic MCSUs decreased in UT-SCC-15, FaDu and SAS, remained the same in UT-SCC-5 and increased in UT-SCC-14. Decreases were observed in the proportion of chronically hypoxic MCSUs in UT-SCC-15, in the fraction of acutely hypoxic MCSUs in UT-SCC-15 and SAS, and in the percentage of hypoxemically hypoxic MCSUs in SAS tumors. After irradiation with 5 fractions, there were no significant changes in hypoxia subtypes. Changes in the overall fraction of hypoxic MCSUs were comparable to corresponding alterations in the proportions of acutely hypoxic MCSUs. There was no correlation between radiation resistance (TCD50) and any of the investigated hypoxic fractions upon fractionated irradiation. Conclusions: This study shows that there are large alterations in the fractions of hypoxia subtypes upon irradiation that can differ from changes in the overall fraction of hypoxic MCSUs.

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

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

    2014-07-01

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

  11. International co-operation in the field of food irradiation

    In 1982, the Directors General of FAO, IAEA and WHO took the initiative in forming the International Consultative Group on Food Irradiation, as an independent body composed of government-designated experts (currently 37 member states). It is the successor of the International Project in the Field of Food Irradiation (IFIP), Karlsruhe which terminated in 1983 after successful complation of its tasks. The major functions of ICGFI, as stated in Declaration, are: - To evaluate global developments; - to provide advice to Member States and the three organizations; - to furnish information through the organizations to the JECFI and CAC. ICGFI addresses matters such as safety assurance, legislation, public information, technical and economical feasibility, training and international trade. Under the Auspices of ICGFI Codes of Food Irradiation Practice for eight different food groups were published. ICGFI organizes workshops on different topics, harmonize legislation and regulation in the field of food irradiation, provides information to the general public, records the files on clearances of radiated food and market testing. (orig.)

  12. Evaluation of onion root tip cell surviving fraction by measuring growing speed irradiated by accelerated heavy ions

    Average growth of germinating onion seed roots irradiated with accelerated heavy ions decreased with increase of absorbed dose, and the ratio to the non-irradiated seeds approached asymptotically to about 40% with increasing of the dose and almost converged at 10 Gy. The converged ratio was about 20% for green sorgo seeds and about 80% for alphalfa seeds. Irradiation of the heavy ions and γ-ray larger than 2 Gy delayed appearance of micronuclei in the onion root tip cells. The delay increased with the increase of linear energy transfer (LET) and absorbed dose. (author)

  13. Fractionated homogenous total-body irradiation prior to bone marrow transplantation

    At the University of Kiel, myeloid and acute lymphatic leukemia is treated since 1983 by total-body irradiation applied prior to bone marrow transplantation. Dose deviations in the midplane caused by the irregular surface and tissue inhomogeneities of the patient are reduced down to +- 3.5% compared to the central ray, with the help of CT-based individual compensators. This method prevents above all an excessive dose to the lungs. The radiobiologic advantages of fractionated irradiation have been employed for all patients treated hitherto (n = 9). At present, a total body dose of 12 Gy in six fractions is applied within three days. There were no undesired acute radiogenic reactions except a mild acute mucositis found in all patients. Chronic side effects, especially in the lungs, were not demonstrated, too. However, the average follow-up time of 149 days has been rather short. One patient died from relapse of leukemia after a total dose of 10 Gy, another patient died because the transplanted bone marrow was rejected, and a third died from catheter sepsis. Six out of nine patients are in complete remission with a maximum index of Karnofsky. The limited experiences gained hitherto show that the homogeneous accelerated-fractionated total-body irradiation offers essential advantages compared to non-compensated single dose irradiation with respect to the prevention of undesired radiogenic effects in sound tissues and that its therapeutic efficacy is at least the same. (orig.)

  14. Combined treatment of the immunoconjugate bivatuzumab mertansine and fractionated irradiation improves local tumour control in vivo

    Background and purpose: To test whether BIWI 1 (bivatuzumab mertansine), an immunoconjugate of the humanized anti-CD44v6 monoclonal antibody BIWA 4 and the maytansinoid DM1, given simultaneously to fractionated irradiation improves local tumour control in vivo compared with irradiation alone. Material and methods: For growth delay, FaDu tumours were treated with 5 intravenous injections (daily) of phosphate buffered saline (PBS, control), BIWA 4 (monoclonal antibody against CD44v6) or BIWI 1 (bivatuzumab mertansine) at two different dose levels (50 μg/kg DM1 and 100 μg/kg DM1). For local tumour control, FaDu tumours received fractionated irradiation (5f/5d) with simultaneous PBS, BIWA 4 or BIWI 1 (two dose levels). Results: BIWI 1 significantly improved local tumour control after irradiation with 5 fractions already in the lower concentration. The dose modifying factor of 1.9 is substantial compared to the majority of other modifiers of radiation response. Conclusion: Because of the magnitude of the curative effect, this approach is highly promising and should be further evaluated using similar combinations with improved tumour-specificity.

  15. Post-irradiation-examination results for absorber material irradiation rig AMIR-6. The results of non-destructive examination for capsules

    Irradiation tests of Absorber Material Irradiation Rig (AMIR) have been continuously conducted, using the experimental fast reactor Joyo. AMIR-6, which was submitted for post-irradiation-examinations (PIE) this time, was irradiated in order to evaluate the limit of failure in control rods and confirm the effect of method for suppression of relocation caused by cracking of boron carbide (B4C) pellets. According to this purpose, gap size between B4C pellet and cladding tube (inner capsule tube), enrichment of 10B, thickness of cladding tube and its material were changed in this test. In addition, thin shroud tube wrapping B4C pellets was used as the method for suppression of relocation. Capsules were loaded in compartments, which had the upper and lower stairs, and irradiation rig AMIR-6 was constructed of seven compartments in total. The irradiation capsule had double tubes, namely inner capsule tube and outer capsule tube. Between these tubes, sodium was filled. AMIR-6 was irradiated at the 6 raw in Joyo Mark-II core up to 106 x 1026 cap/m3 (max. burn-up) and 3.82 x 1026 n/m2 (max, fluence). Irradiation temperatures were evaluated from 530 to 890 degC in design. Extraordinary results were observed for lower capsules by weight measurement performed. So, detailed visual inspection was carried out for these capsules. Consequently, sodium entered from the crack of screwhead attached to the outer tube in three irradiation capsules, whose weight increased. It was recognized that the sodium level between cladding tube and outer tube was lower in six capsules of lower stairs. Cladding crack was found out in three cladding tubes of lower irradiation capsule. It was suggested that the crack become for decrease of strength of cladding tube because those temperature increased at the position where sodium was not filled. The irradiation capsule using a shroud tube showed no diameter increase and ovality in the cladding. It is guessed from the results that the function as the

  16. Effects of single-dose and fractionated cranial irradiation on rat brain accumulation of methotrexate

    The effects of single-dose and fractionated whole-brain irradiation on brain methotrexate (MTX) has been studied in a rat model. The amount of MTX present in the brain 24 hr after a single i.p. dose (100 mg/kg) was the same whether animals were sham irradiated or given a single dose of 2000 rads 6 or 48 hr prior to the drug (6.9, 8.3, and 6.8 pmol MTX/g, wet weight, respectively). Animals sham irradiated or given 2000 rads in 10 fractions over 11 days and treated with an average dose of 1.2 mg MTX/kg i.p. twice a week for 24 weeks did not differ significantly in their brain MTX concentration (7.9 and 8.3 pmol MTX/g, wet weight, respectively). Chronically MTX-treated animals became folate deficient whether they were irradiated or not (450 and 670 pmol folate/g, wet weight, brain in MTX-treated and control animals). Thus, MTX accumulates in the brain with acute or chronic administration, and this accumulation is not altered by this amount of brain irradiation

  17. Changes in hemopoiesis of dying and surviving mice after fractionated irradiation and repeated bone marrow transplantation

    Mice received doses of 3 Gy of 60Co-gamma rays total body irradiation at four-day intervals up to a total dose of 24 Gy. After each dose per fraction half of the animals were injected with 106 bone marrow cells. At four- and nine-day intervals evaluations were made of the blood count, bone marrow and spleen cellularities, and spleen mass. In animals subjected only to irradiation the damage of hemopoietic organs was becoming deeper until the end of observation; the majority of these mice died by nine days after the irradiation with the last dose per fraction (by 37 days of the experiment). The authors consider anemia as the main cause of their death. All of the mice that were given bone marrow injections survived; nine days after the last dose of irradiation the mean cellularities of their bone marrows and spleens were 76.8% and 112.3% of the unirradiated controls respectively. In general, regeneration of erythropoiesis was quite successful, the number of thrombocytes was positively influenced, and the number of leukocytes nearly unchanged in bone marrow recipients when compared with the only irradiated mice. We observed two periods of maximum and one of minimum bone marrow and spleen regeneration, which were not synchronized. These results deny an unrepairable damage to the hemopoietic microenvironment in conditions of our experiment. This paper follows up with our preceding work describing results of an experiment which ended on day 24. (orig.)

  18. Audiological assessment before and after fractionated stereotactic irradiation for vestibular schwannoma

    Purpose: To find the audiological outcome after LINAC-based fractionated stereotactic irradiation (STI). Materials and methods: Twenty-four patients with vestibular schwannoma treated by fractionated STI between 1991 and 1997 had measurable hearing before STI and were followed audiologically for more than 6 months. The pure tone average (PTA) was measured by averaging the air-conduction threshold for five main frequencies (250-4000 Hz) before and periodically after STI in the 24 patients. Several possible prognostic factors for hearing preservation (defined as a PTA change at the last follow-up of less than 10 dB) were investigated. The median follow-up time was 22 months, ranging from 5 to 69 months. The irradiation schedule was 36 Gy in 20 fractions in 5 weeks to 44 Gy in 22 fractions in 6 weeks followed by 4 Gy/1 fraction boost. Results: The pure tone average before STI was distributed from 7 to 73 dB. Fifty percent of patients showed a change in PTA of less than 10 dB, 79.2% of patients showed a change in PTA of less than 20 dB and 20.8% of patients showed a change in PTA of more than 21 dB at the last follow-up. Only one patient (4%) became deaf. Cases with a sudden loss of hearing were more likely to experience hearing preservation than those with gradual loss of hearing (P<0.05). The mean age was younger in patients whose hearing was preserved (P<0.05). Poor pretreatment PTA appeared to linearly correspond to the changes in PTA (regression coefficient 0.78). The size of the tumor was not related to the change in PTA. No relationship was observed between the maximum or peripheral dose and the PTA change. The real benefit of stereotactic boost after small-field fractionated irradiation was not certain. Conclusion: Fractionated STI produced a hearing preservation rate compatible with meticulously collimated multi-spots single fraction irradiation. Further follow-up is required to confirm the long-term benefits of fractionation. (Copyright (c) 1998 Elsevier

  19. Calculation of the internal radiation absorbed dose of 123I-Annexin V

    To estimate absorbed doses by 123I-Annexin V in human, 125I-Annexin V was used as a radiotracer for measuring the distribution of radiolabeled Annexin V in mice. The standard Medical Internal Radiation Dose (MIRD) method was used by Mirdose-3 software in dosimetry estimation. The results show that liver and kidney received 2.77 x 10-3 and 2.71 x 10-3 mGy/MBq, respectively. The red marrow received 1.78 x 10-5 mGy/MBq, and the other organs received doses between 1.5 x 10-4 and 10.5 x 10-4 mGy/MBq. The effective dose was estimated at 5.55 x 10-4 mSv/MBq. Human radiation dosimetry can be performed by the mice biodistribution data and important data for clinical safe trial of 123I-Annexin V are provided. (authors)

  20. Single high-dose irradiation aggravates eosinophil-mediated fibrosis through IL-33 secreted from impaired vessels in the skin compared to fractionated irradiation.

    Lee, Eun-Jung; Kim, Jun Won; Yoo, Hyun; Kwak, Woori; Choi, Won Hoon; Cho, Seoae; Choi, Yu Jeong; Lee, Yoon-Jin; Cho, Jaeho

    2015-08-14

    We have revealed in a porcine skin injury model that eosinophil recruitment was dose-dependently enhanced by a single high-dose irradiation. In this study, we investigated the underlying mechanism of eosinophil-associated skin fibrosis and the effect of high-dose-per-fraction radiation. The dorsal skin of a mini-pig was divided into two sections containing 4-cm(2) fields that were irradiated with 30 Gy in a single fraction or 5 fractions and biopsied regularly over 14 weeks. Eosinophil-related Th2 cytokines such as interleukin (IL)-4, IL-5, and C-C motif chemokine-11 (CCL11/eotaxin) were evaluated by quantitative real-time PCR. RNA-sequencing using 30 Gy-irradiated mouse skin and functional assays in a co-culture system of THP-1 and irradiated-human umbilical vein endothelial cells (HUVECs) were performed to investigate the mechanism of eosinophil-mediated radiation fibrosis. Single high-dose-per-fraction irradiation caused pronounced eosinophil accumulation, increased profibrotic factors collagen and transforming growth factor-β, enhanced production of eosinophil-related cytokines including IL-4, IL-5, CCL11, IL-13, and IL-33, and reduced vessels compared with 5-fraction irradiation. IL-33 notably increased in pig and mouse skin vessels after single high-dose irradiation of 30 Gy, as well as in irradiated HUVECs following 12 Gy. Blocking IL-33 suppressed the migration ability of THP-1 cells and cytokine secretion in a co-culture system of THP-1 cells and irradiated HUVECs. Hence, high-dose-per-fraction irradiation appears to enhance eosinophil-mediated fibrotic responses, and IL-33 may be a key molecule operating in eosinophil-mediated fibrosis in high-dose-per fraction irradiated skin. PMID:26047701

  1. measurement of absorbed dose in mix-dp phantom irradiated by x and gamma rays

    It has been done of x-rays dan gamma rays absorbed dose measurement of mix-dp phantom of 70 kVp.90kvp and 110 kvp x rays kxo-12 medical exposure and cobalt-60 gamma (50 ci) by UD-170A BeO-TLD. Ionization chamber 12 cc NIRS-R2 as reference dosemeter, which was calibrated on primer dosemeter. In X-rays energy used, it was done of absorbed dose measurement on Mix-Dp phantom surface and depth (d= 10cm) beam field area 10 x 10 cm, focus distance (FSD), s=80 cm dose measurement of 90 kvp X-rays on Mix-Dp phantom surface, depth and scattering (d=15 cm) beam field area 12 x 12 cm, focus distance (FSD),s=79 cm and measurement of absorbed dose Co-60 gamma: 5 R, 10R, 20 R, 30R, 40R and 50R by dose rate 0.434 R/min. It was shown that in clinical, effective energy range of X-rays relative lower than dose range Co-60 gamma. BeO-TLD characteristic on energy dependence is low based on TI sensitivity ± 1.3 for energy below 100 keV. Relation between absorbed dose and TL response to 90 kVp X-rays shown that rperm=0.990, r ber=0.995 and r sact=0.962. In measurement of Co-60 gamma absorbed dose by BeO-TLD shown TI sensitivity decrease ± 0.900. The result still needed corrections to achieve optimum measurement of absorbed dose X-rays and gamma by UD-170A BeO-TLD, which were performed optimum fading time and anealling temperature

  2. Effects of modified fractionated irradiation on the growth of sarcoma 180 solid tumor in mouse

    The present experimental study has been designed and carried out to investigate the effects of various doses and timings of fractionated irradiation of 6 MV X-rays obtained from a linear accelerator on sarcoma 180 solid tumors produced in DDO/Lee mouse. A total of 2700 to approx. 2800 cGy(or rad) was delivered with daily dose of 250/ cGy, 350cGy, and 450cGy every other day to the inoculated site starting on day 2,4,6, and 8 post-inoculation and the tumor size change was observed by measuring a maximum circumference of tumor bearing region. The dose experimentally established in the mouse for one half of animals to produce a solid tumor (TSD50) from ascitic mouse sarcoma 180 was 10/sup 3.87/ cells/ml. The effect of fractionated irradiation on days 2 and 4 post-inoculation was inhibitory to the growth of solid form tumor of experimentally produced sarcoma 180 (p<0.001). The growth of tumor was also inhibited when irradiated on days 6 and 8 post-inoculation but the grade was less. Histologically tumor cells of mouse sarcoma 180 produced in the experimental animal were shown to be destroyed and eradicated by radiation once they were responsive to X-irradiation. The present study suggests that a small or early tumor is benefitted by a small daily dose(e.g. 250 cGy) irradiation whereas a moderately advanced tumor is beneficially treated with a relatively high dose (e.g. 450 cGy) irradiation. A large tumor responded very poorly to irradiation

  3. Model of the absorbed dose on a small sphere into a gamma irradiation field

    Several models of the absorbed dose calculated as the energy deposited by the secondary electrons on a small volume sphere are presented. The calculations use the Compton scattering of a uniform photon beam in water, the photon attenuation and the electron stopping power are included. The sphere total absorbed dose is due to the stopping of the electrons generated in three regions: into the sphere volume, ahead and behind the sphere volume. Calculations are performed for spheres of different radius and placed at various depth of the vacuum - water interface. (author)

  4. Effects of fractionated irradiation on the cytoskeleton and basal lamina in parotid glands. An immunohistochemical study

    Cytoskeletal, cytocontractile and basement membrane proteins were studied using the immunofluorescence technique in the parotid gland in female rats after half-side fractionated megavoltage irradiation. The non-irradiated parallel-handled parotid glands served as controls. The qualitative expression of cytoskeletal proteins remained unchanged 10 days following irradiation compared to controls, i.e. cytokeratin was observed but not vimentin, desmin or GFAP (glial fibrillary acidic proteins). Six months after irradiation the cytokeratin expression adjacent to duct lumina was clearly stronger. Actin staining was more pronounced in the periphery of the acini. Ten days after irradiation no alterations of the basal lamina proteins, laminin and fibronectin, were detected. Six months post-irradiation laminin deposits were detected in areas where the entire acini had degenerated and had been replaced by fibrosis. An increased expression of fibronectin was also observed in the stroma at that time, reflecting an increased fibrosis. In areas where the acini remained, laminin immunofluorescence was mainly found in basal laminae of normal thickness, but the mean diameter of the acini seemed to have increased. This indicates a regeneration of acini and a restructuring of the basal lamina of the parenchyma. (orig.)

  5. Food Preservation by Irradiation. Vol. I. Proceedings of an International Symposium on Food Preservation by Irradiation

    In the task of alleviating the distress caused by the world-wide food shortage it is essential to preserve what has been grown and harvested in the fields. Clearly all suitable methods for preserving agricultural produce and food should be made use of. In this context treatment with ionizing radiation has proved its value as an environmentally clean, physical method o f food preservation which is low in its energy requirement, but the volume of food being processed in this way is still low. The introduction o f food irradiation on a global basis poses certain economic, legal, regulatory and health-related questions, the solution o f which requires close international collaboration. Such collaboration between many international, intergovernmental and national organizations began over a decade ago. The need for dissemination and discussion o f information gained through research and development work on this subject became apparent, and a number of inter-regional meetings were held. The last international symposium on the topic was held jointly by FAO and the IAEA in 1972 in Bombay. To review progress made since then, FAO and the IAEA, together with WHO, convened the present Symposium on 21-25 November 1977. It appeared timely to hold this Symposium for the following reasons: (1) Apart from significant scientific work reported in the literature, progress in other directions between 1972 and 1977 had also been made. For example, the number of food items authorized by governments, with or without restriction, had grown from 19 to 26, and the number of countries accepting one or more irradiated foods for human consumption had increased from 11 to 19. (2) Largely on the basis of the work of the International Project in the Field of Food Irradiation (Karlsruhe), already described at the Bombay Symposium, an international expert committee, jointly convened by FAO, the IAEA and WHO in August-September 1976, had made important statements on the philosophy of wholesomeness

  6. Food Preservation by Irradiation. Vol. II. Proceedings of an International Symposium on Food Preservation by Irradiation

    In the task of alleviating the distress caused by the world-wide food shortage it is essential to preserve what has been grown and harvested in the fields. Clearly all suitable methods for preserving agricultural produce and food should be made use of. In this context treatment with ionizing radiation has proved its value as an environmentally clean, physical method of food preservation which is low in its energy requirement, but the volume of food being processed in this way is still low. The introduction of food irradiation on a global basis poses certain economic, legal, regulatory and health-related questions, the solution of which requires close international collaboration. Such collaboration between many international, intergovernmental and national organizations began over a decade ago. The need for dissemination and discussion of information gained through research and development work on this subject became apparent, and a number of inter-regional meetings were held. The last international symposium on the topic was held jointly by FAO and the IAEA in 1972 in Bombay. To review progress made since then, FAO and the IAEA, together with WHO, convened the present Symposium on 21-25 November 1977. It appeared timely to hold this Symposium for the following reasons: (1) Apart from significant scientific work reported in the literature, progress in other directions between 1972 and 1977 had also been made. For example, the number of food items authorized by governments, with or without restriction, had grown from 19 to 26, and the number of countries accepting one or more irradiated foods for human consumption had increased from 11 to 19. (2) Largely on the basis of the work of the International Project in the Field of Food Irradiation (Karlsruhe), already described at the Bombay Symposium, an international expert committee, jointly convened by FAO, the IAEA and WHO in August-September 1976, had made important statements on the philosophy of wholesomeness studies

  7. Surviving defect fraction in 14-MeV neutron-irradiated copper

    The fraction of Frenkel defects that survive in isolated or clustered form during room temperature irradiation of copper has been measured as a function of fluence by a combination of electron microscopy (TEM) and electrical resistivity methods. Both methods indicate that the ratio of surviving to created defects decreased from 12 to 4.7% as the fluence of 14-MeV neutrons increased from 1x1020 to 2.9x1021 n/m2. (orig.)

  8. Measured Wavelength-Dependent Absorption Enhancement of Internally Mixed Black Carbon with Absorbing and Nonabsorbing Materials.

    You, Rian; Radney, James G; Zachariah, Michael R; Zangmeister, Christopher D

    2016-08-01

    Optical absorption spectra of laboratory generated aerosols consisting of black carbon (BC) internally mixed with nonabsorbing materials (ammonium sulfate, AS, and sodium chloride, NaCl) and BC with a weakly absorbing brown carbon surrogate derived from humic acid (HA) were measured across the visible to near-IR (550 to 840 nm). Spectra were measured in situ using a photoacoustic spectrometer and step-scanning a supercontinuum laser source with a tunable wavelength and bandwidth filter. BC had a mass-specific absorption cross section (MAC) of 7.89 ± 0.25 m(2) g(-1) at λ = 550 nm and an absorption Ångström exponent (AAE) of 1.03 ± 0.09 (2σ). For internally mixed BC, the ratio of BC mass to the total mass of the mixture was chosen as 0.13 to mimic particles observed in the terrestrial atmosphere. The manner in which BC mixed with each material was determined from transmission electron microscopy (TEM). AS/BC and HA/BC particles were fully internally mixed, and the BC was both internally and externally mixed for NaCl/BC particles. The AS/BC, NaCl/BC, and HA/BC particles had AAEs of 1.43 ± 0.05, 1.34 ± 0.06, and 1.91 ± 0.05, respectively. The observed absorption enhancement of mixed BC relative to the pure BC was wavelength dependent for AS/BC and decreased from 1.5 at λ = 550 nm with increasing wavelength while the NaCl/BC enhancement was essentially wavelength independent. For HA/BC, the enhancement ranged from 2 to 3 and was strongly wavelength dependent. Removal of the HA absorption contribution to enhancement revealed that the enhancement was ≈1.5 and independent of wavelength. PMID:27359341

  9. Accelerated repopulation of mouse tongue epithelium during fractionated irradiations or following single doses

    Mouse tongue mucosa was established as an animal model to study repopulation after large single doses or during continuous irradiation. A top-up irradiation technique was used employing priming doses or fractionated treatment to the whole snout (300 kV X-rays) followed by local test doses (25 kV X-rays) to elicit denudation in a confined field of the inferior tongue surface. Clearcut quantal dose-response curves of ulcer incidence were obtained to all protocols; animal morbidity, i.e. body weight loss was minimal. Repopulation following priming doses of 10 and 13 Gy started with a delay of at least 3 days and then progressed rapidly to nearly restore original tissue tolerance by day 11. During continuous fractionation over 1 to 3 weeks with 5 fractions/week and doses per fraction of 2.5, 3 and 3.5 Gy, repopulation was small in week one but subsequently increased to fully compensate the weekly dose at all dose levels. Additional measurements of cell density during a 4 weeks course of 5 x 3 Gy or 5 x 4 Gy per week showed only moderate depletion to 67% of the control figures. The fact that rapid repopulation is achieved at relatively moderate damage levels should be taken into account when the timing of a treatment split is considered. (author). 18 refs.; 7 figs.; 1 tab

  10. Understanding and predicting the behaviour of silver base neutron absorbers under irradiations; Comprehension et prediction du comportement sous irradiation neutronique d`alliages absorbants a base d`argent

    Desgranges, C

    1998-12-31

    The effect of neutron irradiation induced transmutations on the swelling of AgInCd (AIC) alloys used as neutron absorber in the control rods of Pressurized Water Reactors has been studied both experimentally and theoretically. Effective atomic volumes have been determined in synthetic AgCdInSn alloys with various compositions and containing fcc and hc phases, representative of irradiated AIC (Sn is a transmutation product). Swelling is shown to result first from the transmutation of Ag into Cd and of In into Sn, both with larger effective volume than the mother atom, and second from grain boundaries precipitation of s still less dense hc phase when solid solubility of transmuted products is exceeded. For both fcc and hc phases, we have determined profiles at the temperatures in the vicinity of the operating temperature. Unusual characteristics of second phase growth at grain boundaries induced by transmutations are identified on a simple binary alloy model: kinetics is controlled by irradiation temperature which scales diffusivities and flux which scales transmutation rates, as well as by the grain size in the underlying matrix. To address the AgInCdSn alloys, a novel technique is proposed to model diffusion in multicomponent alloys. It is based on a linearization of a simple atomistic model. With a single set of parameters, for each phase, our model well reproduces our interdiffusion measurements in quaternary alloys as well as existing interdiffusion experiments in binary alloys. Finally this diffusion model implemented with a moving interface algorithm is used to model the growth of the second phase induced by transmutation in the AIC under irradiation. (authors) 74 refs.

  11. Degradation and decoloration of textiles wastewater by electron beam irradiation: Effect of energy, current and absorbed dose

    Bakar, Khomsaton Abu; Zulkafli,; Hashim, Siti A' aisah [Malaysian Nuclear Agency (Nuclear Malaysia), Bangi 43000 Kajang Selangor (Malaysia); Ahmad, Pauzi [Universiti Kebangsaan Malaysia, 43600 UKM, Bangi Selangor (Malaysia)

    2014-09-03

    In this study, electron beam accelerator (EB) was used to treat textiles wastewater from Rawang Industrial Park, Selangor. The objectives were to determine effective energy, beam current and absorbed dose required for decoloration and degradation of the textiles effluent. The textiles effluent was irradiated in a batch with various energy of 1MeV to 3MeV at constant beam current of 30mA. It was observed that removal of color and COD increases with higher beam energy. The EB energy of 1MeV effectively to removed 58% color and 19% COD. For textile effluent sample irradiated at fix energy of 1MeV and 3Mev but at different beam current 10mA, 20mA and 30mA. It was observed that removal of color and COD increases with the increased of beam current at each energy. However removal of color was significantly better at 1Mev as compared to 3Mev. In the case of textiles effluent, irradiated at doses of 17, 20,25,30, 35, 100 and 200kGy using 30 kW power of EB (1Mev, 30mA), results shows removal of BOD{sub 5}, COD and color were in the range 9%-33%, 14%-38% and 43%-78% respectively.

  12. Degradation and decoloration of textiles wastewater by electron beam irradiation: Effect of energy, current and absorbed dose

    In this study, electron beam accelerator (EB) was used to treat textiles wastewater from Rawang Industrial Park, Selangor. The objectives were to determine effective energy, beam current and absorbed dose required for decoloration and degradation of the textiles effluent. The textiles effluent was irradiated in a batch with various energy of 1MeV to 3MeV at constant beam current of 30mA. It was observed that removal of color and COD increases with higher beam energy. The EB energy of 1MeV effectively to removed 58% color and 19% COD. For textile effluent sample irradiated at fix energy of 1MeV and 3Mev but at different beam current 10mA, 20mA and 30mA. It was observed that removal of color and COD increases with the increased of beam current at each energy. However removal of color was significantly better at 1Mev as compared to 3Mev. In the case of textiles effluent, irradiated at doses of 17, 20,25,30, 35, 100 and 200kGy using 30 kW power of EB (1Mev, 30mA), results shows removal of BOD5, COD and color were in the range 9%-33%, 14%-38% and 43%-78% respectively

  13. Study of chromosome aberration repair after acute or fractionated X-irradiation in human peripheral lymphocytes

    Pure human peripheral blood has been subjected to a single irradiation with the dose of 125 and 250R and by fractions with the doses of 125+125 R in the following periods of the cell cycle: 0, 2, 4, 6, 8, 12, 16, 24, 30, 40 and 45 hrs. The following types of structural chromosome aberrations are counted on metaphase plates with a good chromosome scattering: dicentrics, rings, interstitial deletions, symmetric translocations, chromatide and chromosome fragments. The data on polycentrics and rings prove to be most characteristic: the frequency of these aberrations in the case of single irradiation for all periods of the ''presynthetic'' Gsub(I) period is stable varying in the range of 17-20% in the case of a 125 R dose and 66-73% in the case of a 250 R dose. Their frequency decreased for both doses of irradiation in later periods and reached 1% by the end of the synthetic period. The fractionated effect of two doses 125 R each gives the following values of polycentric and ring formation: second hour - 44,15%, fourth - 50,82%, sixth - 55,15% eighth -58,32% (maximum), twelfth - 55,48%. The descending tendency is preserved till the end of the presynthetic period and in the synthetic period. The statistic processing of results shows statistically authentic differences between fractionated and single irradiation in the output of polycentrics and rings, as well as other types of aberrations and breaks per cell. The data obtained permit to conclude that repair processes are undulatory and are characterized by maximum intensity in the first hours of presynthetic period which weakens to the 8th hour and then strengthens again almost to the end of the synthetic period

  14. Development of in vitro models for investigating spatially fractionated irradiation: physics and biological results

    Blockhuys, S; Vanhoecke, B; Paelinck, L; Bracke, M; DeWagter, C

    2009-03-01

    We present different in vitro experimental models which allow us to evaluate the effect of spatially fractionated dose distributions on metabolic activity. We irradiated a monolayer of MCF-7/6 human breast cancer cells with a steep and a smooth 6 MV x-ray dose gradient. In the steep gradient model, we irradiated the cells with three separate small fields. We also developed two smooth gradient models. In the first model, the cells are cultured in a T25 flask and irradiated with a smooth dose gradient over the length of the flask, while in the second one, the cells are cultured in a 96-well plate and also irradiated over the length of the plate. In an attempt to correlate the spatially fractionated dose distributions with metabolic activity, the effect of irradiation was evaluated by means of the MTT assay. This assay is used to determine the metabolic activity by measuring the amount of formazan formed after the conversion of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) by cellular dehydrogenases. The results obtained with our different models suggest a dose-specific effect on metabolic activity, characterized by an increased formazan optical density occurring in the dose range 1.0-4.0 Gy in the steep dose gradient model and in the dose ranges 4.2-6.5 Gy and 2.3-5.1 Gy in the two smooth dose gradient models. The corresponding times for maximal formazan accumulation were 5-7 days in the steep dose gradient model and day 9-13 and day 9-11 in the smooth dose gradient models. Altogether, our results suggest that the MTT assay may be used as a biological dose-response meter to monitor the radiotherapeutic effectiveness.

  15. Reemergence of apoptotic cells between fractionated doses in irradiated murine tumors

    The purpose of this investigation was to follow up our previous studies on the development of apoptosis in irradiated murine tumors by testing whether an apoptotic subpopulation of cells reemerges between fractionated exposures. Mice bearing a murine ovarian carcinoma, OCa-I, were treated in vivo with two fractionation protocols: two doses of 12.5 Gy separated by various times out to 5 days and multiple daily fractions of 2.5 Gy. Animals were killed 4 h after the last dose in each protocol, and the percent apoptosis was scored from stained histological sections made from the irradiated tumors according to the specific features characteristic of this mode of cell death. The 12.5+12.5 Gy protocol yielded a net total percent apoptosis of about 45% when the two doses were separated by 5 days (total dose = 25 Gy), whereas the 2.5 Gy per day protocol yielded about 50% net apoptotic cells when given for 5 days (total dose = 12.5 Gy). These values are to be compared to the value of 36% apoptotic cells that is yielded by large single doses (> 25 Gy). Thus, these results indicate that an apoptotic subpopulation of cells reemerged between the fractions in both protocols, but the kinetics appeared to be delayed in the 12.5+12.5 Gy vs. the multiple 2.5 Gy protocol. This reemergence of cells with the propensity for radiation-induced apoptosis between fractionated exposures is consistent with a role for this mode of cell death in the response of tumors to radiotherapy and may represent the priming of a new subpopulation of tumor cells for apoptosis as part of normal tumor homeostasis to counterbalance cell division. 25 refs., 3 figs., 1 tab

  16. Single high-dose irradiation aggravates eosinophil-mediated fibrosis through IL-33 secreted from impaired vessels in the skin compared to fractionated irradiation

    Lee, Eun-Jung, E-mail: forejs2@yuhs.ac [Department of Radiation Oncology, Yonsei University College of Medicine, Seoul 120-752 (Korea, Republic of); Kim, Jun Won, E-mail: JUNWON@yuhs.ac [Department of Radiation Oncology, Yonsei University College of Medicine, Seoul 120-752 (Korea, Republic of); Yoo, Hyun, E-mail: gochunghee@yuhs.ac [Department of Radiation Oncology, Yonsei University College of Medicine, Seoul 120-752 (Korea, Republic of); Kwak, Woori, E-mail: asleo02@snu.ac.kr [Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul 151-747 (Korea, Republic of); Choi, Won Hoon, E-mail: wonhoon@yuhs.ac [Department of Radiation Oncology, Yonsei University College of Medicine, Seoul 120-752 (Korea, Republic of); Cho, Seoae, E-mail: seoae@cnkgenomics.com [C& K Genomics, Seoul National University Mt.4-2, Main Bldg. #514, SNU Research Park, NakSeoungDae, Gwanakgu, Seoul 151-919 (Korea, Republic of); Choi, Yu Jeong, E-mail: yunk9275@daum.net [Department of Radiation Oncology, Yonsei University College of Medicine, Seoul 120-752 (Korea, Republic of); Lee, Yoon-Jin, E-mail: yjlee8@kirams.re.kr [Division of Radiation Effects, Research Center for Radiotherapy, Korea Institute of Radiological & Medical Sciences, Seoul 139-760 (Korea, Republic of); Cho, Jaeho, E-mail: jjhmd@yuhs.ac [Department of Radiation Oncology, Yonsei University College of Medicine, Seoul 120-752 (Korea, Republic of)

    2015-08-14

    We have revealed in a porcine skin injury model that eosinophil recruitment was dose-dependently enhanced by a single high-dose irradiation. In this study, we investigated the underlying mechanism of eosinophil-associated skin fibrosis and the effect of high-dose-per-fraction radiation. The dorsal skin of a mini-pig was divided into two sections containing 4-cm{sup 2} fields that were irradiated with 30 Gy in a single fraction or 5 fractions and biopsied regularly over 14 weeks. Eosinophil-related Th2 cytokines such as interleukin (IL)-4, IL-5, and C–C motif chemokine-11 (CCL11/eotaxin) were evaluated by quantitative real-time PCR. RNA-sequencing using 30 Gy-irradiated mouse skin and functional assays in a co-culture system of THP-1 and irradiated-human umbilical vein endothelial cells (HUVECs) were performed to investigate the mechanism of eosinophil-mediated radiation fibrosis. Single high-dose-per-fraction irradiation caused pronounced eosinophil accumulation, increased profibrotic factors collagen and transforming growth factor-β, enhanced production of eosinophil-related cytokines including IL-4, IL-5, CCL11, IL-13, and IL-33, and reduced vessels compared with 5-fraction irradiation. IL-33 notably increased in pig and mouse skin vessels after single high-dose irradiation of 30 Gy, as well as in irradiated HUVECs following 12 Gy. Blocking IL-33 suppressed the migration ability of THP-1 cells and cytokine secretion in a co-culture system of THP-1 cells and irradiated HUVECs. Hence, high-dose-per-fraction irradiation appears to enhance eosinophil-mediated fibrotic responses, and IL-33 may be a key molecule operating in eosinophil-mediated fibrosis in high-dose-per fraction irradiated skin. - Highlights: • Single high-dose irradiation aggravates eosinophil-mediated fibrosis through IL-33. • Vascular endothelial cells damaged by high-dose radiation secrete IL-33. • Blocking IL-33 suppressed migration of inflammatory cells and cytokine secretion. • IL

  17. Single high-dose irradiation aggravates eosinophil-mediated fibrosis through IL-33 secreted from impaired vessels in the skin compared to fractionated irradiation

    We have revealed in a porcine skin injury model that eosinophil recruitment was dose-dependently enhanced by a single high-dose irradiation. In this study, we investigated the underlying mechanism of eosinophil-associated skin fibrosis and the effect of high-dose-per-fraction radiation. The dorsal skin of a mini-pig was divided into two sections containing 4-cm2 fields that were irradiated with 30 Gy in a single fraction or 5 fractions and biopsied regularly over 14 weeks. Eosinophil-related Th2 cytokines such as interleukin (IL)-4, IL-5, and C–C motif chemokine-11 (CCL11/eotaxin) were evaluated by quantitative real-time PCR. RNA-sequencing using 30 Gy-irradiated mouse skin and functional assays in a co-culture system of THP-1 and irradiated-human umbilical vein endothelial cells (HUVECs) were performed to investigate the mechanism of eosinophil-mediated radiation fibrosis. Single high-dose-per-fraction irradiation caused pronounced eosinophil accumulation, increased profibrotic factors collagen and transforming growth factor-β, enhanced production of eosinophil-related cytokines including IL-4, IL-5, CCL11, IL-13, and IL-33, and reduced vessels compared with 5-fraction irradiation. IL-33 notably increased in pig and mouse skin vessels after single high-dose irradiation of 30 Gy, as well as in irradiated HUVECs following 12 Gy. Blocking IL-33 suppressed the migration ability of THP-1 cells and cytokine secretion in a co-culture system of THP-1 cells and irradiated HUVECs. Hence, high-dose-per-fraction irradiation appears to enhance eosinophil-mediated fibrotic responses, and IL-33 may be a key molecule operating in eosinophil-mediated fibrosis in high-dose-per fraction irradiated skin. - Highlights: • Single high-dose irradiation aggravates eosinophil-mediated fibrosis through IL-33. • Vascular endothelial cells damaged by high-dose radiation secrete IL-33. • Blocking IL-33 suppressed migration of inflammatory cells and cytokine secretion. • IL-33 is

  18. Single fraction prophylactic cranial irradiation for small cell carcinoma of the lung

    The effectiveness of a single 8-Gy fraction prophylactic cranial irradiation regime was assessed in 106 patients with small-cell carcinoma of the lung. All patients had limited stage disease and received combination chemotherapy consisting of either cisplatin or carboplatin with ifosfamide, etoposide, and vincristine (VICE). Cranial irradiation was administered 48 h after the first cycle of chemotherapy and was well tolerated. Actual 2-year survival was 35% and cranial relapse occurred in 22% of those patients who achieved complete remission. This compares favourably with a cranial relapse rate of 45% incomplete remitters previously reported with the same chemotherapy regime after a minimum follow-up of 2 years where PCI was not used. Formal psychometric testing was performed retrospectively on a series of 25 long-term survivors of whom 14 were taken from this reported series. Whilst 75% of patients were impaired on at least one test with 68% performing badly in the most complex task, this was not associated with clinically detectable neurological damage and the patients did not complain of memory or concentration difficulties. In conclusion, single fraction PCI, when used with platinum based combination chemotherapy, appears to be equally effective but may be less neurotoxic than the more standard fractionated regimes

  19. Experimental and theoretical determination of absorbed microwave dose rate distributions in phantom heads irradiated by an aperture source

    A thermographic technique is used to determine absorbed microwave energy distribution in phantom monkey and human heads irradiated by an aperture source. The phantom heads are brain equivalent tissue spheres and a bone and brain tissue geometric model of a monkey head. The results of the experiment are compared to patterns obtained from theoretical calculations, indicating good general agreement between experimental and theoretical data. The penetration of microwave energy is less for the phantom human head than for the monkey head. The overall poor penetration of the radiation due to the 2450 MHz aperture source used in this experiment indicates a need for further research using frequency and aperture dimensions as parameters to obtain desired microwave absorption patterns for both biological experiments and therapeutic applications. (author)

  20. Amelioration of acute oral mucositis by Keratinocyte growth factor: fractionated irradiation

    Purpose: The aim of the present study was to quantify the protective efficacy of recombinant human keratinocyte growth factor (rHuKGF) in oral mucosa. Methods and Materials: Mouse tongue mucosal ulceration was analyzed as the clinically relevant end point. Fractionated irradiation of the snout with 5 daily fractions of 3 Gy was followed by graded test doses, given to a test area of the lower tongue, on Day 7. rHuKGF was injected s.c. in daily doses of 5 mg/kg before radiotherapy, during radiotherapy, over the weekend break, or a combination. Moreover, single rHuKGF injections (5 or 15 mg/kg) were given on Day -1 or on Day 4. Results: In a single-dose control experiment, the ED50, i.e., the dose after which ulcer induction is expected in 50% of the mice, was 10.9 ± 0.7 Gy. Fractionated irradiation without keratinocyte growth factor rendered an ED50 for test irradiation of 5.6 ± 3.7 Gy. Keratinocyte growth factor increased the ED50 values to 7.8 ± 3.3 Gy (Days -3 to -1, p=0.01), 8.3 ± 1.6 Gy (Days -4 to -2, p=0.0008), 10.5 ± 1.4 Gy (Days 0 to +2, p=0.0002), 11.0 ± 0.5 Gy (Days 0 to +4, p=0.002), 10.6 ± 1.4 Gy (Days +4 to +6, p=0.0021), 10 ± 0.07 (Days -3 to +1, p=0.0001) or 11.0 ± 0.02 (Days +4 to +8, p=0.0001). This is equivalent to compensation of approximately 1.5 fractions of 3 Gy when rHuKGF is given before radiotherapy and 3-4 fractions in all other protocols by rHuKGF treatment. Single rHuKGF injections were similarly (5 mg/kg) or more (15 mg/kg) effective. Conclusions: In conclusion, these results indicate a marked increase in oral mucosal radiation tolerance by rHuKGF, which is most pronounced if the growth factor is applied during fractionated radiotherapy. The effect seems to be based on complex mechanisms, predominantly changes in both epithelial proliferation and differentiation processes

  1. Response of human tumor cell lines in vitro to fractionated irradiation

    Matthews, J.H.; Meeker, B.E.; Chapman, J.D.

    1989-01-01

    The surviving fraction of human tumor cell lines after 2 Gy (SF2) varies between 0.1 and 0.8. It has been postulated that differences in inherent radiosensitivity of tumor cells are a major determinant of radiation response in vivo. Assays of inherent radiosensitivity based on acute survival are being developed as predictors of tumor response which often assume that the same inherent radiosensitivity persists throughout a fractionated treatment. We have investigated the response of 2 human tumor cell lines (A549 and MCF7) with different inherent radiosensitivities to in vitro fractionated irradiation. A549 cells had an SF2 of 0.62 and a mean inactivation dose (D) of 3.07 Gy whereas MCF7 cells had an SF2 of 0.30 and a D of 1.52 Gy. Split dose repair capacity (at equal survival levels) was less for A549 than for MCF7 cells and recovery kinetics for both cell lines were substantially longer than those of rodent cell lines. Survival after 5 fractions of 2 Gy given 12 hr apart at 37 degrees C was near to that predicted from the acute survival curve, assuming complete repair and no proliferation. Acute survival of A549 cells which survived 5 fractions of 2 Gy given 12 hr apart was similar to the acute survival of unirradiated cells. When A549 cells were incubated at 22 degrees C between 5 fractions of 2 Gy given 12 hr apart, proliferation and split dose repair were substantially inhibited. These studies support the proposals to use in vitro inherent radiosensitivity assays for the prediction of in vivo response of tumors to fractionated treatment.

  2. Response of human tumor cell lines in vitro to fractionated irradiation.

    Matthews, J H; Meeker, B E; Chapman, J D

    1989-01-01

    The surviving fraction of human tumor cell lines after 2 Gy (SF2) varies between 0.1 and 0.8. It has been postulated that differences in inherent radiosensitivity of tumor cells are a major determinant of radiation response in vivo. Assays of inherent radiosensitivity based on acute survival are being developed as predictors of tumor response which often assume that the same inherent radiosensitivity persists throughout a fractionated treatment. We have investigated the response of 2 human tumor cell lines (A549 and MCF7) with different inherent radiosensitivities to in vitro fractionated irradiation. A549 cells had an SF2 of 0.62 and a mean inactivation dose (D) of 3.07 Gy whereas MCF7 cells had an SF2 of 0.30 and a D of 1.52 Gy. Split dose repair capacity (at equal survival levels) was less for A549 than for MCF7 cells and recovery kinetics for both cell lines were substantially longer than those of rodent cell lines. Survival after 5 fractions of 2 Gy given 12 hr apart at 37 degrees C was near to that predicted from the acute survival curve, assuming complete repair and no proliferation. Acute survival of A549 cells which survived 5 fractions of 2 Gy given 12 hr apart was similar to the acute survival of unirradiated cells. When A549 cells were incubated at 22 degrees C between 5 fractions of 2 Gy given 12 hr apart, proliferation and split dose repair were substantially inhibited. These studies support the proposals to use in vitro inherent radiosensitivity assays for the prediction of in vivo response of tumors to fractionated treatment. PMID:2912934

  3. Effect of single and fractionated x-irradiation on maze learning ability of mice

    Fifty-six-day-old male ddk mice at the starting of the investigation were used as subjects through the experiment for 64 weeks. After 15 days' preliminary training, and 16 times of weekly trial training using complete maze, 15 mice received a single 224 rads of x-rays (S group), another 15 mice received two 112 rads spaced two weeks apart (F group) and another 15 mice were sham-irradiated (Control group). Then those mice were tested on the multiple T-maze with nine-choice points and change of performance was observed in terms of errorchoices by giving one test trial a week. We introduced the concept of ''confusional trials'' as an index for surmising to what extent mice failed to exhibit good maze learning habits. In the results, the F group showed significantly worse performance than the two other groups at early stages, opposite to it the S group exhibited the same, but at late stages after irradiation. The worse performance of F group should be considered to be due to the psychological after-effect to fractionated irradiation and that for S group could be assumed to be due to the acceleration of aging by the irradiation. (auth.)

  4. Haemopoiesis in murine bone marrow and spleen after fractionated irradiation and repeated bone marrow transplantation. I

    Erythropoiesis was studied in mice repeatedly exposed to doses of 3 Gy of 60Co γ-rays at 4-day intervals up to a total dose of 24 Gy on the basis of total bone marrow and spleen cellularity follow-up and analysis of myelograms and splenograms. Half the number of the mice received 106 nuclear cells of syngeneic bone marrow after each fractional radiation dose. It was mainly the spleen which was involved in the adaptation and regeneration of erythropoiesis, its contribution to total erythropoiesis in bone marrow recipients having been as high as 73.9% (day 20 of experiment, total dose 15 Gy). In mice only irradiated, the number of nuclear cells of erythroid lineage decreased to zero values sooner in the spleen (day 16 of experiment, total dose 12 Gy) than in the bone marrow (day 24 of experiment, total dose 18 Gy). The analysis of the results of collections made on day 9 after the last irradiation revealed, however, that the hemopoietic microenvironment of the spleen and hemopoietic cells capable of differentiation in the erythroid direction were so resistant to irradiation in mice only irradiated that erythropoiesis in their spleens exhibited signs of regeneration even after the highest total dose of 24 Gy. (author). 2 figs., 3 tabs., 12 refs

  5. 77 FR 50113 - ASTM International-Food and Drug Administration Workshop on Absorbable Medical Devices: Lessons...

    2012-08-20

    ... Absorbable Medical Devices: Lessons Learned From Correlations of Bench Testing and Clinical Performance... Bench Testing and Clinical Performance.'' FDA is co-sponsoring the workshop together with ASTM... establishing correlations between in vitro and in vivo degradation of absorbable implant devices, and...

  6. The Effect of 60Co Gamma Irradiation on Various Fractions of Human Blood-Plasma Proteins

    The potential usefulness of employing ionizing radiation to cold-sterilize biomedical products has stimulated interest in characterizing the radiation sensitivity of various biologicals like vitamins, antibiotics, enzymes, antibodies and blood plasma fractions. This report presents findings on the sensitivity of haemagglutinin activity in human sera exposed to cobalt-60 gamma radiation. At doses tested between 0.2 and 5.0 Mrad, α-isohaemagglutinins were found to be more readily inactivated than ß-isohaemagglutinins, but neither was completely inactivated in this range. Sterility, clotting and antihaemophilic activity were also assessed on irradiated and freeze-dried preparations of human plasma with no significant differences in response detected. (author)

  7. Effects of irradiation with conventional and multiple daily fractionation on serum amylase activity

    The behaviour of serum α-amylase activity was determined in patients with head and neck cancer treated by radiation therapy. The levels of serum α-analyse activity during conventional and multiple daily fractionation were compared. Starting from the second day of treatment an increase of serum α-amylase activity was observed. The increase and its duration depended on the total daily dose: after the first day of treatment a linear correlation between serum levels and total daily dose could be observed. The size of the amylase increase correlated to the proportion of salivary gland tissue included in the irradiated volume. (orig.)

  8. Incompatible SLA bone marrow graft in the pig after fractionated irradiation and administration of cyclosporin A

    A series of fractionated partial irradiations which consisted of either 3 gray x 6 times or 3 gray x 4 times, combined with pharmacological immunosuppression (Cyclosporin A: Cs-A) ensure a SLA semidifferent bone marrow graft in the pig. Bone marrow and peripheral blood lymphocytes chimerism was readily detectable. No graft versus host disease (GVHD) symptoms were noticed as long as Cs-A was given at a sufficient dose. However when Cs-A treatment was stopped GVHD or rejection of the graft developed rapidly

  9. Radiation tolerance dose of the spinal cord following conventionally fractionated irradiation

    Yamada, Shogo; Hoshi, Akihiko; Takai, Yoshihiro; Hoshino, Fumiya; Mochizuki, Yukio; Kanehira, Chihiro; Kaneta, Koichi.

    1987-08-01

    409 patients whose spinal cord were irradiated over 30 Gy with conentionally fractionated method were surveied to study the colleration between the dose of spinal cord and the incidence of radiation myelitis. Radiation myelitis was observed in 26 cases including 3 transverse myelitis ones. 5 year incidences of transverse myelitis calculated with life table method were approximately 0 % at 40 Gy, 5 % at 50 Gy, 10 % at 60 Gy and 20 % at 70 Gy. The radiation tolerance dose of the spinal cord was considered to be 50 Gy.

  10. Radiation tolerance dose of the spinal cord following conventionally fractionated irradiation

    409 patients whose spinal cord were irradiated over 30 Gy with conentionally fractionated method were surveied to study the colleration between the dose of spinal cord and the incidence of radiation myelitis. Radiation myelitis was observed in 26 cases including 3 transverse myelitis ones. 5 year incidences of transverse myelitis calculated with life table method were approximately 0 % at 40 Gy, 5 % at 50 Gy, 10 % at 60 Gy and 20 % at 70 Gy. The radiation tolerance dose of the spinal cord was considered to be 50 Gy. (author)

  11. Recovery and cycle progression in multicell spheroids after fractionated γ-irradiation and combined hyperthermic treatment

    Spheroids of V79 cells were subjected to fractionated irradiation with two doses of γ-radiation. In addition, a two hours hyperthermic treatment at 420C immediately following the first dose was applied. Cycling and resting cells of this in-vitro tumour model were then assayed for survival as function of the fractionation interval. In parallel, changes in cycle progression between the doses were measured by means of cytofluorometry. As main proliferative effects induced by this combined radiation and heat treatment transient S-phase blocking of cycling and recruitment of resting cells were observed. The split-dose survival curve displayed considerable synergistic action of heat and radiation and a six hours delay of Elkind-recoverey in both cycling and resting cells. (orig.)

  12. Cytogenetic studies on recipients of allogeneic bone marrow transplants after fractionated total body irradiation

    Cytogenetic findings from the bone marrow (BM) and the peripheral blood (PB) of nine consecutive patients after allogeneic bone marrow transplantation (BMT) for acute or chronic myelogenous leukaemia are reported. After a conditioning regimen consisting of cyclophosphamide and fractionated total body irradiation (TBI) given in five or six fractions of 2 Gy, persistence of host cells was detected in four out of seven cases with permanent engraftment. While one of these patients relapsed 4 months after host cells had been found in BM and PB, the other patients stayed relapse-free 124, 257 and 347 d after grafting. Before transplantation, the leukaemic cells in all three cases carried unique cytogenetic abnormalities giving the opportunity to distinguish the leukaemic population from chromosomally non-aberrant cells thought to represent residual normal host cells. As the persisting host cells after BMT lacked any cytogenetic abnormalities, it is suggested that they were members of residual normal clones not involved in the leukaemic process. (author)

  13. Standardized methods to verify absorbed dose in irradiated food for insect control. Proceedings of a final research co-ordination meeting

    Irradiation to control insect infestation of food is increasingly accepted and applied, especially as a phytosanitary treatment of food as an alternative to fumigation. However, unlike other processes for insect control, irradiation does not always result in immediate insect death. Thus, it is conceivable that fresh and dried fruits and tree nuts, which have been correctly irradiated to meet insect disinfestation/quarantine requirements, may still contain live insects at the time of importation. There is, however, a movement by plant quarantine authorities away from inspecting to ensure the absence of live insects in imported consignments towards examining through administrative procedures that a treatment required by law has been given. Nevertheless, there is a need to provide plant quarantine inspectors with a reliable objective method to verify that a minimum absorbed dose of radiation was given to supplement administrative procedures. Such an objective method is expected to bolster the confidence of the inspectors in clearing the consignment without delay and to facilitate trade in irradiated commodities. The Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture initiated a co-ordinated research project (CRP) in 1994 to generate data on the verification of absorbed dose of irradiation in fresh, dried fruits and tree nuts for insect disinfestation/quarantine purposes. A standardized label dose indicator available commercially was used to verify the minimum/maximum absorbed dose of the irradiated commodities for these purposes as required by regulations in certain countries. It appears that such a label dose indicator with certain modifications could be made available to assist national authorities and the food industry to verify the absorbed dose of irradiation to facilitate trade in such irradiated commodities. This TECDOC reports on the accomplishments of this co-ordinated research project and includes the papers presented by the participants

  14. Cataracts after total body irradiation and marrow transplantation: a sparing effect of dose fractionation

    Two hundred seventy-seven patients, who have been followed for 1 to 12 years after marrow transplantation, have been examined for cataract development. In preparation for transplantation, 96 patients with aplastic anemia were conditioned with chemotherapy only, while 181 patients (two with aplastic anemia and 179 with a hematologic malignancy) were conditioned with a regimen of total body irradiation (TBI) and chemotherapy. TBI was delivered from two opposing 60Co sources at an exposure rate of 4 to 8 cGy/min, either as a single dose of 10 Gy (105 patients) or in fractions (76 patients). To date, 86 patients have developed cataracts. Kaplan-Meier product limit estimates of the incidence of cataracts for patients given chemotherapy only and no TBI, single-dose TBI, and fractionated TBI are 19, 80, 18%, respectively. On the basis of proportional hazards regression analyses, patients given single-dose TBI had a relative risk of developing cataracts that was 4.7-fold higher than in patients given fractionated TBI or chemotherapy only, suggesting a significant sparing effect with use of TBI dose fractionation

  15. Study by internal friction of curing low temperature irradiation defects in graphite

    Micromechanical properties and anelastic effects of neutrons irradiated graphites at 300 and 770K are investigated by internal friction analysis and elasticity modulus variations. Defects created by irradiation are studied and evolution versus dose and annealing is followed

  16. EPR evaluation of absorbed doses in γ-irradiated animal bone tissues

    By the ESR method accumulation of CO2- radicals in γ-irradiated bone tissues of swine, chicken, cattle, navaga and other small fish of the cod family, hen's eggs shell was studied to reveal the fact of radiation exposure and to evaluate exposure dose received during radiation treatment of food stuffs. It is shown that in the range of doses 0-10 kGy dependence of the radicals concentration on dose is of linear character, while coefficient of the radicals radiation-chemical yield variation for diverse biological types of bone tissue does not exceed 30 %. Potentiality of using the method of additive doses for the ESR dosimetry of radiation-treated beef was considered. It is shown that the linear model used in the additive doses method provides overrated results compared to the exponential model

  17. Skin toxicity during hypo fractionated breast irradiation in patient with early breast cancer

    Radiotherapy is an important component in the treatment of breast cancer. (1) Many women with an early stage of breast cancer are candidates for a breast conservation therapy, which combines both conservative surgery and radiotherapy. (2) According to the data from some series, an estimated 90% of the patients treated with radiotherapy for breast cancer will develop a degree of radiation-induced dermatitis. (3) The severity of the skin reactions during and following the breast irradiation is influenced by both treatment-related and patient-related factors. The treatment - related factors include the fraction size (the dose delivered with each treatment), the total dose delivered, the volume of tissue treated, the type of radiation (4) and the addition of chemotherapy. (5) The patient-related factors include breast size, smoking, axillary lymphocele drainage before treatment, age, and infection of the surgical wound. (6) A hypo fractionation radiotherapy is alternative for a standard fractionation radiotherapy for women with early stage of breast cancer after conservative surgery. The aim of the study was to analyse the acute skin reactions during a hypo fractionated radiotherapy in patients with early breast cancer at our institution. Materials and methods: Twenty patients with early stage of breast cancer (Stadium I and II) and conservative surgery (quadrantectomy of breast with ipsilateral axillary dissection) were analysed. The patients were treated with 6MV x rays on LINAC, using tangential fields with 2.65Gy per fraction and the total dose prescribed to target volume was 42,4 Gy. These patients were observed for acute skin toxicity during the second week and at the end of the treatment. We evaluated dryness, epilation, pigmentation, changes and eritema, dry desquamation (clinically characterized by scaling and pruritus) and moist desquamation (characterized by serious oozing and exposure of the dermis). By using the radiation therapy oncology group’s (RTOG

  18. New specific absorbed fractions for annihilation radiation as a step towards a more individual dosimetry in nuclear diagnostics

    In order to establish a more individual dosimetry for treatments involving radiopharmaceuticals like nuclear diagnostics and targeted radionuclide therapy, this project aims to calculate Specific Absorbed Fractions (SAFs) for annihilation radiation over a broad range of physiognomies. For the estimation of the SAFs varying with different physiognomic parameters, the study uses the Monte Carlo N-Particle Transport Code (MCNP) which during the last decades proved to be a powerful and reliable tool for dose calculations in human tissue. The human phantoms are generated from an additional software called The Body Builder which enables the user to generate a phantom according to his specifications. The phantoms generated by The Body Builder are based on the Christy/Eckermann phantoms with a first interpolation made on their coefficients and a subsequent transformation into the equivalent MCNP surface representation. The spectrum of age groups ranges from 1 to 21 years, covering both sexes. As source organs we chose the biokinetical compartments of 18 F-fluorodeoxyglucose (FDG) used in the model of Hays and Segall. A homogeneous distribution of the activity within the source organ is assumed, which means that the annihilation photons of 511 keV are considered to be emitted from an isotropic and homogenous volume source. In order to get good statistics the number of photons simulated ranged between 2 and 20 million, depending on size and distance between source and target organs. Results. Considering all possible combinations between source and target organs, representing 21 age groups of both sexes, one gets more than 30 000 SAFs. The work is still in progress during the preparation of this paper, but first results are already presented here. The relative error of the Monte Carlo simulation for every SAF mentioned below does not exceed 1,1%. An additional uncertainty factor of approximately 0,5% is introduced by using the p-mode of MCNP. The results of the different age

  19. Nd:YAG laser irradiation on temporary teeth carious tissue using 12% diamine silver fluoride as a photo-absorber - a morphological study

    Since Nd:YAG laser radiation was first introduced in Dentistry various photo-absorbers were employed with the intent of improving its efficacy when used on dental carious tissue. The purpose of the present study was to analyze the influence of this radiation using Scanning and Optical microscopy over carious tissue of primary teeth using two photo-absorbers. 15 primary human teeth were used and, in each one, 3 cavity preparations were performed. Specimens were then submitted to an in vitro demineralizing environment during 18 days. Two of the cavities of each specimen were laser irradiated using the Nd:YAG laser with 60 mJ of energy per pulse, 10 Hz and average power of 0,6 W. The 12% diamine silver fluoride or the mineral coal were used as photo-absorbers. The third cavity of the specimens was used as a control and received no laser irradiation. Samples were transversally cut and the section analyzed by SEM and OM. Results showed that the 12% diamine silver fluoride is an efficient photo-absorber and, when used it the Nd:YAG laser, leading to melting and resolidification of the carious tissue. It can be concluded that the 12% diammine silver fluoride presents advantages over the mineral coal as a photo absorber when used in primary teeth as it promotes and improves the efficacy of laser irradiation. This substance also works as a barrier on the carie progression in deeper areas such as the infected and necrotic zones. (author)

  20. Sexual dimorphism of newborn mouse epithalamus after fractionated X-irradiation at late stage of organogenesis

    Fractionated X-irradiation with 3 x 0.95-1.35 Gy on gestational days 11-13 in the mouse results in two discrete, clearly distinguishable forms of an epithalamic malformation observable on gestational day 18. Type A is characterized by a rhombic shape of the dorsal diencephalic sulcus which first narrows at the occipital edge. The type B lesion is characterized by a rather narrow epithalamus with a sandglass-shaped dorsal diencephalic sulcus. With the exception of the group with the lowest radiation dose (3 x 0.95 Gy) the type B lesion predominates. Type B lesions occur in female fetuses at a higher frequency than in males. This is again most marked in the 3 x 1.05 Gy dosage group where the type B lesion occurs five times more frequently in females than in males. This sexual dimorphism in the reaction pattern of the epithalamus after X-irradiation in utero can best be explained by postulating a causal link with the forebrain lesions which were recently shown to exhibit similar sexual dimorphism. We therefore postulate a retrograde transsynaptic degeneration of the thalamo-cortical fibres that develop pre-term, which is significantly expressed only after a low X-irradiation dose, but is partly abolished in the higher dosage groups. (orig./MG)

  1. Computer simulation of fractionated radiotherapy: Further results and their relevance to percutaneous irradiation and brachytherapy

    Basing on previous papers, the present communication considers the simulation of the radiotherapeutic treatments of glioblastoma multiforme, rectum adenocarcinoma, and gynaecological tumors of cervix uteri (squamous and adenocarcinoma) in spheroid culture. Starting with a single tumor cell in a nutrient medium and after the corresponding growth of the tumor spheroids, varying irradiation schemes are applied to the carcinoma and are compared with regard to tumor kill effectivity using the LQ-model. The two first-mentioned carcinoma are exposed to the dose fractionation schemes standard-, super-, hyperfractionation, and weekly high single dose. The result is that hyperfractionation (3x1.5 Gy/day) and weekly high single dose (1x6 Gy/week) yield the most effective tumor cell kill. The weekly high single dose may be realized by some different irradiation techniques, e.g. stereotactic irradiation or interstitial high dose rate brachytherapy. The treatment of the cervix uteri tumors is performed by a combined therapy form (high dose rate brachytherapy and percutaneous irradition). A comparing simulation of two typical regimens yield a nearly equivalent tumor kill effectivity. By the integration of in vitro tumor growth and clinical treatment schemes in a computer model, the possibility is made available to test the effectivity of variable regimens with the help of computer experiments. (orig.)

  2. Combined effect of carcinogenic n-nitrosodimethylamine precursors and fractioned γ-irradiation on tumor development in rats

    The influence of combined action of N-nitrosodimethylamine (NDMA) and fractioned γ-irradiation on tumor development in rats was investigated. Both the tumor frequency and tumor plurality coefficient have been studied for two types of treatment: precursors of NDMA (amidopyrine and/or sodium nitrite (SN)) alone and the combination 'precursors plus radiation'. Tumor frequency decreased by about 11% after combination of γ-irradiation and precursors in comparison with precursors alone. Nevertheless, treatment with SN and γ-irradiation did not change tumor frequency in comparison with SN alone. Irradiation of rats treated with precursors led to an increased tumor plurality coefficient

  3. Fractional absorption of active absorbable algal calcium (AAACa) and calcium carbonate measured by a dual stable-isotope method

    With the use of stable isotopes, this study aimed to compare the bioavailability of active absorbable algal calcium (AAACa), obtained from oyster shell powder heated to a high temperature, with an additional heated seaweed component (Heated Algal Ingredient, HAI), with that of calcium carbonate. In ...

  4. Combination Processes in Food Irradiation. Proceedings of an International Symposium on Combination Processes in Food Irradiation

    Processes in Food Irradiation was held by the IAEA and FAO at the Bandaranaike Memorial International Conference Hall in Colombo on 24-28 November 1980, and the present volume contains the proceedings. One of the most effective means demonstrated of increasing the efficacy of irradiation in the control of food spoilage is the combination of a low irradiation dose with a mild heat treatment. Promising results were reported for the shelf-life extension of mangoes and papayas, and the disinfestation of dried dates. Commercial application of the heat-irradiation treatment for some fruits is expected to follow soon. The Symposium covered other topics, such as the mechanisms of sensitization of microorganisms by physical and chemical agents, improvement of the microbiological quality of foods by combination processes, and the aspects of the wholesomeness and legislation of the food irradiation process. A key issue in the general discussion was the recommendation on the acceptability of food irradiated up to an overall average dose of 10 kGy. This important recommendation had been achieved at a recently convened Joint FAO/IAEA/WHO Expert Committee on the Wholesomeness of Irradiated Foods (27 October — 3 November 1980, Geneva). The breakthrough on the toxicological acceptability constitutes a firm basis for going ahead speedily with the development of practical applications of food irradiation, which should take its rightful place among other food preservation methods in helping to provide more and better food to a world in need. The sponsoring organizations hope that the publication of these proceedings will encourage further research and development of food irradiation to the benefit of mankind

  5. Facts about food irradiation. A series of fact sheets from the International Consultative Group on Food Irradiation

    The safety and benefits of foods processed by ionizing radiation are well documented. In an effort to provide governments, especially those of developing countries, with scientifically accurate information on issues of general interest to the public, the International Consultative Group on Food Irradiation (ICGFI), which was established under the aegis of the Food and Agriculture Organization of the United Nations (FAO), the World Health Organization (WHO), and the IAEA, decided at its 7th Annual Meeting in Rome, Italy, on October 1990, to issue a series of ''Fact Sheets'' on the subject. ICGFI, an inter-governmental body with a membership of 37 governments, has as one of its mandates the function to provide information to Member States of the FAO, WHO, and IAEA and to the three organizations themselves on the safe and proper use of food irradiation technology. The Fact Sheets included here cover issues relating to: status and trends; scientific and technical terms; food irradiation and radioactivity; chemical changes in irradiated food; nutritional quality of irradiated foods; genetic studies; microbiological safety of irradiated food; irradiation and food safety; irradiation and food additives and residues; packaging of irradiated foods; safety of irradiation facilities; controlling the process; food irradiation costs; and irradiated foods and the consumer. The Fact Sheets have been separately indexed and included in the INIS Database under Reference Numbers 23011206-23011217, 23011319 and 23012743. The Fact Sheets were first issued by the ICGFI Secretariat (Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria) in May 1991

  6. Comparison of US and FRG post-irradiation examination procedures to measure statistically significant failure fractions of irradiated coated-particle fuels

    Two methods for measuring failure fraction on irradiated coated-particle fuels have been developed, one in the United States (the IMGA system - Irradiated-Microsphere Gamma Analyzer) and one in the Federal Republic of Germany (FRG) (the PIAA procedure - Postirradiation Annealing and Beta Autoradiography). A comparison of the two methods on two standardized sets of irradiated particles was undertaken to evaluate the accuracy, operational procedures, and expense of each method in obtaining statistically significant results. From the comparison, the postirradiation examination method employing the IMGA system was found to be superior to the PIAA procedure for measuring statistically significant failure fractions. Both methods require that the irradiated fuel be in the form of loose particles, each requires extensive remote hot-cell facilities, and each is capable of physically separating failed particles from unfailed particles. Important differences noted in the comparison are described

  7. Fractionated total lymphoid irradiation as preparative immunosuppression in high risk renal transplantation: clinical and immunological studies

    Twenty-two patients at high risk to reject renal allografts have been treated with fractionated total lymphoid irradiation (FTLI) prior to transplantation of primary (2), secondary (16) or teritary (4) renal allografts. All patients undergoing retransplantation had rapidly rejected previous grafts. At 24 months following transplantation, 72% of grafts were functioning in the TLI group compared with a 38% graft function in an historical control group of recipients receiving secondary or tertiary grafts and treated with conventional immunosuppression. Important variables in determining success of transplantation following fractionated TLI include the dose of TLI, the interval from radiation to transplantation, and maintenance, post-transplant immunosuppressive therapy. Optimal results were achieved with 2500 rads delivered in 100 rad fractions followed by transplantation within two weeks, and a tapering prednisone schedule and maintenance azathioprine post-transplantation. Seventeen patients had significant complications of the radiation treatment and there was one death, prior to transplantation, associated with pneumonitis. In vitro assessment of immune function demonstrated marked peripheral T cell depletion and loss of in vitro responsiveness to mitogen and allogeneic stimulation following FTLI. The administration of donor bone marrow at the time of transplantation did not produce chimerism. The results suggest that when properly utilized FTLI can produce effective adjunctive immunosuppression for clinical transplantation

  8. Fractionated total lymphoid irradiation as preparative immunosuppression in high risk renal transplantation

    Najarian, J.S.; Ferguson, R.M.; Sutherland, D.E.; Slavin, S.; Kim, T.; Kersey, J.; Simmons, R.L.

    1982-10-01

    Twenty-two patients at high risk to reject renal allografts have been treated with fractionated total lymphoid irradiation (FTLI) prior to transplantation of primary (2), secondary (16) or tertiary (4) renal allografts. All patients undergoing retransplantation had rapidly rejected previous grafts. At 24 months following transplantation, 72% of grafts were functioning in the TLI group compared with a 38% graft function in an historical control group of recipients receiving secondary or tertiary grafts and treated with conventional immunosuppression. Important variables in determining success of transplantation following fractionated TLI include the dose of TLI, the interval from radiation to transplantation, and maintenance post-transplant immunosuppressive therapy. Optimal results were achieved with 2500 rads delivered in 100 rad fractions followed by transplantation within two weeks, and a tapering prednisone schedule and maintenance azathioprine post-transplantation. Seventeen patients had significant complications of the radiation treatment and there was one death, prior to transplantation, associated with pneumonitis. In vitro assessment of immune function demonstrated marked peripheral T cell depletion and loss of in vitro responsiveness to mitogen and allogeneic stimulation following FTLI. The administration of donor bone marrow at the time of transplantation did not produce chimerism. The results suggest that when properly utilized FTLI can produce effective adjunctive immunosuppression for clinical transplantation.

  9. Fractionated total lymphoid irradiation as preparative immunosuppression in high risk renal transplantation: clinical and immunological studies

    Najarian, J.S.; Ferguson, R.M.; Sutherland, D.E.; Slavin, S.; Kim, T.; Kersey, J.; Simmons, R.S.

    1982-10-01

    Twenty-two patients at high risk to reject renal allografts have been treated with fractionated total lymphoid irradiation (FTLI) prior to transplantation of primary (2), secondary (16) or teritary (4) renal allografts. All patients undergoing retransplantation had rapidly rejected previous grafts. At 24 months following transplantation, 72% of grafts were functioning in the TLI group compared with a 38% graft function in an historical control group of recipients receiving secondary or tertiary grafts and treated with conventional immunosuppression. Important variables in determining success of transplantation following fractionated TLI include the dose of TLI, the interval from radiation to transplantation, and maintenance, post-transplant immunosuppressive therapy. Optimal results were achieved with 2500 rads delivered in 100 rad fractions followed by transplantation within two weeks, and a tapering prednisone schedule and maintenance azathioprine post-transplantation. Seventeen patients had significant complications of the radiation treatment and there was one death, prior to transplantation, associated with pneumonitis. In vitro assessment of immune function demonstrated marked peripheral T cell depletion and loss of in vitro responsiveness to mitogen and allogeneic stimulation following FTLI. The administration of donor bone marrow at the time of transplantation did not produce chimerism. The results suggest that when properly utilized FTLI can produce effective adjunctive immunosuppression for clinical transplantation.

  10. Fractionated half body irradiation for palliation of multiple symptomatic bone metastases from solid tumors

    This was a phase I-II nonrandomized study that explored the toxicity and response of fractionated half-body irradiation (F-HBI) in patients with multiple symptomatic osseous metastases. The patients had no premedication and received 10 Gy in 5 fractions with a dose rate of 15 cGy/min. At the Cancer Institute Hospital, 9 patients were treated by this technique (1 upper and lower F-HBI, 6 upper F-HBI, 2 lower F-HBI). All patients were female and had adenocarcinomas (8 breast and 1 lung). Adverse effects were myelosuppression, vomiting and partial alopecia. But hematologic toxicity was treated with blood transfusion or G-CSF. All toxicity was transient, and no pneumonitis nor radiation-related deaths occurred. When given as palliation, F-HBI was found to relieve pain in 80% of the patients. In 10% of the patients the pain relief was complete. The mean time to achieve pain relief in responders after F-HBI was 9 days. The pain relief was long-lasting and continued without need of reirradiation for 40% of the remaining patient's life. This treatment modality appears to be well tolerated and effective in patients with multiple symptomatic osseous metastases. The optimal indications, dose and fractionation for F-HBI should be further explored in randomized trials. (author)

  11. Fractionated half body irradiation for palliation of multiple symptomatic bone metastases from solid tumors

    Sekiguchi, Kenji; Hayashi, Shinya; Sunagawa, Yoshimitsu; Sougawa, Mitsuharu; Nakazawa, Masanori; Yamashita, Takashi (Japanese Foundation for Cancer Research, Tokyo (Japan). Hospital)

    1992-06-01

    This was a phase I-II nonrandomized study that explored the toxicity and response of fractionated half-body irradiation (F-HBI) in patients with multiple symptomatic osseous metastases. The patients had no premedication and received 10 Gy in 5 fractions with a dose rate of 15 cGy/min. At the Cancer Institute Hospital, 9 patients were treated by this technique (1 upper and lower F-HBI, 6 upper F-HBI, 2 lower F-HBI). All patients were female and had adenocarcinomas (8 breast and 1 lung). Adverse effects were myelosuppression, vomiting and partial alopecia. But hematologic toxicity was treated with blood transfusion or G-CSF. All toxicity was transient, and no pneumonitis nor radiation-related deaths occurred. When given as palliation, F-HBI was found to relieve pain in 80% of the patients. In 10% of the patients the pain relief was complete. The mean time to achieve pain relief in responders after F-HBI was 9 days. The pain relief was long-lasting and continued without need of reirradiation for 40% of the remaining patient's life. This treatment modality appears to be well tolerated and effective in patients with multiple symptomatic osseous metastases. The optimal indications, dose and fractionation for F-HBI should be further explored in randomized trials. (author).

  12. Development of standardized methods to verify absorbed dose of irradiated fresh and dried fruits, tree nuts in trade

    Investigations were carried out on standardization of desired process control parameters such as dose distribution in trade containers, container standardization and development of 'label' dosimeters. A prototype 'label' dose indicators Sterins for threshold doses of 125 Gy and 300 Gy was studied. Dose distribution was studied using fresh fruits and tree nuts in trade and standardized containers with varying product densities. The distribution of absorbed doses was measured by Fricke, Gammachrome YR, clear Polymethylmethacrylate (PMMA), EthanolChlorobenzene (ECB) and Sterin 300. These values are given as Dmax/Dmin ratios in relation to product bulk densities. It was observed that bulk densities varied greatly among different products depending on the types of fruits, containers and pattern of loading which also affected dose distribution. Dmax/Dmin obtained by proper dose mapping could be kept low by arranging proper irradiation conditions which ensured uniform dose distribution. Prototype 'label' dose indicators like Sterins and clear PMMA were used for dose mapping along with the standard primary and secondary dosimeters. Sterins and clear PMMA were also studied for their dosimetric properties, particularly for use in label dosimetry. Sterins 125 and 300 evaluated visually showed their integrity at their threshold doses. The word NOT on Sterin 125 eclipsed after 115 Gy and on Sterin 300 after 270 Gy dose. Clear PMMA samples of 410 mm thickness irradiated at 200-1000 Gy showed linear response and had postirradiation stability for over a month storage at normal temperatures (21-35 deg. C) and humidities. These could be investigated further for developing as 'label' dosimeters in insect control quarantine treatment. Other low dose indicators studied such as coloured perspex, dye solutions were not found useful at quarantine dose levels. Further investigations are required for developing a 'label' dosimeter for commercial use. (author)

  13. Allogeneic bone marrow transplantation in adults after fractionated body irradiation and high dose cyclophosphamide

    The authors present short and long-term results of allogeneic bone marrow transplantation after hyper-fractionated total body irradiation and high dose cyclophosphamide in ten patients treated for leukaemia during th period 1985-89. Three patients died from complications connected to the transplantation, while seven are living free from leukaemia 18 to 59 months after transplantation. Two patients need treatment for chronic graft versus host disease. Allogeneic bone marrow transplantation is expensive and risky. Close cooperation between clinicians and laboratory specialists is essential. The treatment increases long term survival and probably cures certain patients with leukaemia. Some of the patients will need treatment for chronic graft versus host disease and other late sequelae. 19 refs., 2 tabs

  14. Morphological changes in the rat liver following lethal and fractionated telecobalt irradiation studied by transmission and scanning electron microscopy

    Fully grown male albino rats were treated with a single abdominal telecobalt irradiation of 2.000 r or with fractionated irradiation of the right side of the epigastrium with 15 x 500 r. A few days after, the animals were perfusion fixated. One day after irradiation with 2.000 r, the epithelial cells exhibit only slight changes. Three days after the treatment, the glycogen content of the cells is increased. The damage pattern of the endothelial cells of the sinus wall is particularly interesting. After fractionated irradiation of the liver with a total of 7.500 r, a different pattern is found which is similar to the pattern provoked by other noxae. After 120 days, group necroses can be found. (MG)

  15. International Cooperation to Establish Standard Operating Procedure (SOP) for Quarantine Management of Irradiated Foods in International Trade

    · Development of SOPs through various research activities such as building international cooperation, and analysing current status of food irradiation in domestic and international markets, export and import, international market size, and of R and D - Analysis of examples for quarantine management in agricultural product exporting countries and use of irradiation technology for agricultural product quarantine, and changes in international quarantine management - Analysis of SOPs for food irradiation quarantine in international organization (CODEX, IPPC, WHO). U.S, EU, China, India, and Australia. - Collaborative researches of India/Korea and China/Korea entered into an agreement for market trials · Publishment of irradiation quarantine management SOPs agreed to CODEX standards - Collaborative researches for quarantine management, avoiding Technical Barrier to Trade (TBT), and Sanitary Phytosanitary Measures were conducted, and advanced SOPs agreed with WTO/FTA system were published

  16. Diversification of existing reference phantoms in nuclear medicine: Calculation of specific absorbed fractions for 21 mathematical phantoms and validation through dose estimates resulting from the administration of (18)F-FDG.

    Blaickner, Matthias; Kindl, Peter

    2008-12-01

    Current dose assessment in nuclear medicine patient studies relies on published S-values, which are, in turn, based on calculated specific absorbed fractions (SAFs) available for a limited number of anthro-pomorphic computational phantoms. In order to take the individual physiognomy of patients more into account, this study aimed to broaden the supply of phantoms and their respective SAFs. An ensemble of 21 mathematical phantoms was submitted to the Monte Carlo Code MCNP4c2 for the purpose of calculation of SAFs for annihilation radiation. These values were incorporated into an internal dose assessment following the Medical Internal Radiation Dose (MIRD) schema and relying on published biokinetic data for intravenous administration of (18)F-FDG. The results were compared with data from the ICRP, MIRD reports and concurrent calculations with OLINDA/EXM. A very good agreement with sources relying on the SAFs of Cristy and Eckerman (i.e., the ICRP and OLINDA/EXM) was observed, with the absorbed dose in lung being the only exception. In the case of dose to red marrow, the King Spiers factors were omitted in the three-factor approximation, which led to a precise accordance with the Cristy/Eckerman values. Summarizing, one can say that the coincidence with published data justifies the method chosen and demonstrates successfully the expansion of available reference phantoms for dose assessment in nuclear medicine. PMID:19111050

  17. Benefits of online in vivo dosimetry for single-fraction total body irradiation

    Eaton, David J., E-mail: davideaton@nhs.net [Department of Radiotherapy, Royal Free Hospital, London (United Kingdom); Warry, Alison J. [Department of Radiotherapy Physics, University College London Hospital, London (United Kingdom); Trimble, Rachel E.; Vilarino-Varela, Maria J.; Collis, Christopher H. [Department of Radiotherapy, Royal Free Hospital, London (United Kingdom)

    2014-01-01

    Use of a patient test dose before single-fraction total body irradiation (TBI) allows review of in vivo dosimetry and modification of the main treatment setup. However, use of computed tomography (CT) planning and online in vivo dosimetry may reduce the need for this additional step. Patients were treated using a supine CT-planned extended source-to-surface distance (SSD) technique with lead compensators and bolus. In vivo dosimetry was performed using thermoluminescent dosimeters (TLDs) and diodes at 10 representative anatomical locations, for both a 0.1-Gy test dose and the treatment dose. In total, 28 patients were treated between April 2007 and July 2013, with changes made in 10 cases (36%) following test dose results. Overall, 98.1% of measured in vivo treatment doses were within 10% of the prescribed dose, compared with 97.0% of test dose readings. Changes made following the test dose could have been applied during the single-fraction treatment itself, assuming that the dose was delivered in subportions and online in vivo dosimetry was available for all clinically important anatomical sites. This alleviates the need for a test dose, saving considerable time and resources.

  18. Analyse of the international recommendations on the calculation of absorbed dose in the biota

    This paper evaluates the recommendations of ICRP which has as objective the environmental radioprotection. It was analysed the recommendations 26, 60, 91, 103 and 108 of the ICRP. The ICRP-103 defined the concept of animal and plant of reference (APR) to be used in the RAP based on the calculation of absorbed dose based on APR concept. This last view allows to build a legal framework of environmental protection with a etic, moral and scientific visualization, more defensible than the anthropomorphic concept

  19. In vivo dosimetry of high-dose fractionated irradiation in an experimental set-up with rats

    Fortan, L.; Van Hecke, H.; Van Duyse, B.; De Neve, W.; De Meerleer, B. [Ghent Rijksuniversiteit (Belgium). Kliniek voor Radiotherapie en Kerngeneeskunde; Pattyn, P.; Van Renthergem, K. [Ghent University (Belgium). Dept. of Surgery

    1995-12-01

    The feasibility to irradiate a limited section of a rat abdomen with well-defined edges was assessed. Because of the relative small volume involved, in vivo dosimetry with TLDs was necessary in providing us information about the accuracy of the irradiation method. Three to five days prior to the start of the radiotherapy treatment, two plastic strips - each containing a TLD-dosimeter (Harshaw TLD10 LiF rods, 1 mm dia x 6 mm) sealed in polyethylene tubing, and a lead bean - were implanted in the rat abdomen. The plastic strips made a closed loop around the bowel, through the mesenterium, and were fixed with a single stitch on the inner abdominal wall. One loop was made in the hepatic area; another was made in the lower abdomen, around the rectosigmoid. Conscious animals were irradiated using a purpose-build plexi-holder, with rear legs immobilised to avoid longitudinal movements. The implanted lead beans enabled us to simulate the rat prior to each radiation session. This way, the radiation field could be set up individually for each rat, in such way that the rectosigmoid area received full dose and the hepatic area received no irradiation dose at all. Irradiation was carried out, using 5 MV photons of a linear accelerator. Fifteen animals per group were irradiated according a conventional (2.0 Gy / fraction; 5 fractions / week) or a hyperfractionated (1.6 Gy / fraction; 2 daily fractions; 5 days / week) schedule, with different total doses. Prior to implantation, TLDs were individually calibrated and checked for stability. After removal from the abdomen . TLDs were tested again for accuracy. TLDs with an unacceptable read-out curve were rejected (about 2 to 4 TLDs per group of 15). The obtained accumulated doses - as determined by TLD read-outs-were comparable to the theoretical doses, indicating that fractionated radiation of small fields, with well defined mark off, in rats is feasible.

  20. Identification and absorbed dose determination in irradiated kiwi by electron paramagnetic resonance; Identificacao e medida de dose absorvida em kiwi irradiado utilizando ressonancia paramagnetica eletronica

    Jesus, Edgar F.O. de; Lopes, Ricardo T. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia; Rossi, Alexandre M. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)

    1997-12-01

    A methodology for identification and absorbed dose determination in irradiated Kiwi with doses between 200 and 1000 Gy is present. Measurement are performed by Electron Paramagetic Resonance (ESR) in the flesh of the fruit after alcohol extration that removes water and soluble substances. The signal used is the radial produced in cellulose by radiation that shows to be stable during the usefull life of the fruit and that is not present in non-irradiated samples. Reference samples are not necessary to dose determination and the results shows that 85% of the calculated values are found to be within {+-} 15% of the applied initial dose. (author). 9 refs., 5 figs., 2 tabs.

  1. Dose Calculation Evolution for Internal Organ Irradiation in Humans

    The International Commission of Radiation Units (ICRU) has established through the years, a discrimination system regarding the security levels on the prescription and administration of doses in radiation treatments (Radiotherapy, Brach therapy, Nuclear Medicine). The first level is concerned with the prescription and posterior assurance of dose administration to a point of interest (POI), commonly located at the geometrical center of the region to be treated. In this, the effects of radiation around that POI, is not a priority. The second level refers to the dose specifications in a particular plane inside the patient, mostly the middle plane of the lesion. The dose is calculated to all the structures in that plane regardless if they are tumor or healthy tissue. In this case, the dose is not represented by a point value, but by level curves called 'isodoses' as in a topographic map, so you can assure the level of doses to this particular plane, but it also leave with no information about how this values go thru adjacent planes. This is why the third level is referred to the volumetrical description of doses so these isodoses construct now a volume (named 'cloud') that give us better assurance about tissue irradiation around the volume of the lesion and its margin (sub clinical spread or microscopic illness). This work shows how this evolution has resulted, not only in healthy tissue protection improvement but in a rise of tumor control, quality of life, better treatment tolerance and minimum permanent secuelae

  2. Dose Calculation Evolution for Internal Organ Irradiation in Humans

    Jimenez V., Reina A.

    2007-10-01

    The International Commission of Radiation Units (ICRU) has established through the years, a discrimination system regarding the security levels on the prescription and administration of doses in radiation treatments (Radiotherapy, Brach therapy, Nuclear Medicine). The first level is concerned with the prescription and posterior assurance of dose administration to a point of interest (POI), commonly located at the geometrical center of the region to be treated. In this, the effects of radiation around that POI, is not a priority. The second level refers to the dose specifications in a particular plane inside the patient, mostly the middle plane of the lesion. The dose is calculated to all the structures in that plane regardless if they are tumor or healthy tissue. In this case, the dose is not represented by a point value, but by level curves called "isodoses" as in a topographic map, so you can assure the level of doses to this particular plane, but it also leave with no information about how this values go thru adjacent planes. This is why the third level is referred to the volumetrical description of doses so these isodoses construct now a volume (named "cloud") that give us better assurance about tissue irradiation around the volume of the lesion and its margin (sub clinical spread or microscopic illness). This work shows how this evolution has resulted, not only in healthy tissue protection improvement but in a rise of tumor control, quality of life, better treatment tolerance and minimum permanent secuelae.

  3. Histologic effect of fractionated doses of selectively applied /sup 60/Co irradiation to the teeth of albino rats

    Sweeney, W.T.; Elzay, R.P.; Levitt, S.H.

    1977-01-01

    This study compares the effects of fractionated 2400, 4800 and 7200 rad doses of Co-60 irradiation on the formed and developing teeth of the rats. The 7200 rad dosage was found to cause damage to both odontoblasts and ameloblasts of developing incisors but to spare previously formed molars.

  4. Histologic effect of fractionated doses of selectively applied 60Co irradiation to the teeth of albino rats

    This study compares the effects of fractionated 2400, 4800 and 7200 rad doses of Co-60 irradiation on the formed and developing teeth of the rats. The 7200 rad dosage was found to cause damage to both odontoblasts and ameloblasts of developing incisors but to spare previously formed molars

  5. Clinical and experimental study of the radioprotective effect of riboxine in the case of low dose rate fractionated irradiation

    In experiments with dogs (fractionated gamma-irradiation, accumulated dose 1 Gy) as well as in clinical testing of the group of men, recieved 0.25 Gy being engaged in the Chernobyl NPS disaster repairment, the positive influence of riboxin (purine nucleoside0 course treatment on parameters of peripheral blood and non-specific ressitance system has been shown

  6. Characterization of gamma irradiated plasticized carboxymethyl cellulose (CMC)/gum arabic (GA) polymer blends as absorbents for dyestuffs

    Sayeda M Ibrahim; Issa M Mousaa; Mervat S Ibrahim

    2014-05-01

    Polymer blends based on carboxymethylcellulose (CMC) and gum arabic (GA) were prepared by solution casting method. Glycerol was added to the polymer blend solution as a plasticizer with different ratios (2.5, 5, 10 and 20%). Then, the plasticized blends were exposed to gamma irradiation at different doses (5, 10 and 20 kGy). The physical properties of the plasticized polymer blends were investigated in terms of gel fraction (%) and swelling percent (%). Thermal properties were investigated by TGA. Also, the structure of the plasticized polymer blends was characterized by Fourier transform infrared spectroscopy. Scanning electron microscope was investigated in order to examine the compatibility between two polymers in the blend and also between polymer blend and plasticizer. The prepared plasticized polymer blends were used as an adsorbent for different dyestuffs. The sorption of dyestuffs by the plasticized polymer blend was determined by a method based on spectroscopic analysis. The results showed that the plasticized polymer blend has a high affinity for basic, acid, reactive and direct dyes. The obtained results showed that using glycerol as plasticizer improved the swellability of polymer blend and also the dye uptake (%).

  7. Fractionation for Whole Breast Irradiation: An American Society for Radiation Oncology (ASTRO) Evidence-Based Guideline

    Purpose: In patients with early-stage breast cancer treated with breast-conserving surgery, randomized trials have found little difference in local control and survival outcomes between patients treated with conventionally fractionated (CF-) whole breast irradiation (WBI) and those receiving hypofractionated (HF)-WBI. However, it remains controversial whether these results apply to all subgroups of patients. We therefore developed an evidence-based guideline to provide direction for clinical practice. Methods and Materials: A task force authorized by the American Society for Radiation Oncology weighed evidence from a systematic literature review and produced the recommendations contained herein. Results: The majority of patients in randomized trials were aged 50 years or older, had disease Stage pT1-2 pN0, did not receive chemotherapy, and were treated with a radiation dose homogeneity within ±7% in the central axis plane. Such patients experienced equivalent outcomes with either HF-WBI or CF-WBI. Patients not meeting these criteria were relatively underrepresented, and few of the trials reported subgroup analyses. For patients not receiving a radiation boost, the task force favored a dose schedule of 42.5 Gy in 16 fractions when HF-WBI is planned. The task force also recommended that the heart should be excluded from the primary treatment fields (when HF-WBI is used) due to lingering uncertainty regarding late effects of HF-WBI on cardiac function. The task force could not agree on the appropriateness of a tumor bed boost in patients treated with HF-WBI. Conclusion: Data were sufficient to support the use of HF-WBI for patients with early-stage breast cancer who met all the aforementioned criteria. For other patients, the task force could not reach agreement either for or against the use of HF-WBI, which nevertheless should not be interpreted as a contraindication to its use.

  8. Absorbed dose at subcellular level by Monte Carlo simulation for a 99mTc-peptide with nuclear internalization

    The utility of radiolabeled peptides for the early and specific diagnosis of cancer is being investigated around the world. Recent investigations have demonstrated the specificity of 99mTc-bombesin conjugates to target breast and prostate cancer cells. The novel idea of adding the Tat (49-57) peptide to the radiopharmaceutical in order to penetrate the cell nucleus is a new proposal for therapy at cellular level. 99mTc radionuclide produces Auger energy of 0.9 keV/decay and internal conversion electron energy of 15.4 keV/decay, which represent 11.4% of the total 99mTc energy released per decay. It is expected that the dose delivered at specific microscopic levels in cancer cells induce a therapeutic effect. The aim of this research was to assess in vitro internalization kinetics in breast and prostate cancer cells of 99mTc-Tat(49-57)-bombesin and to evaluate the radiation absorbed dose at subcellular level simulating the electron transport. The pen main program from the 2006 version of the Penelope code was used to simulate and calculate the absorbed dose by Auger and internal conversion electron contribution in the membrane, cytoplasm and nucleus of Pc-3 prostate cancer and MCF7 and MDA human breast cancer cell lines. Nuclear data were obtained from the 2002 BNM-LNHB 99mTc decay scheme. The spatial distribution of the absorbed doses to the membrane, cytoplasm and nucleus were calculated using a geometric model built from real images of cancer cells. The elemental cell composition was taken from the literature. The biokinetic data were obtained evaluating total disintegrations in each subcellular compartment by integration of the time-activity curves acquired from experimental data. Results showed that 61, 63 and 46% of total disintegrations per cell-bound 99mTc-Tat-Bn activity unit occurred in the nucleus of Pc-3, MCF7 and MDA-MB231 respectively. 99mTc--Tat-Bn absorbed doses were 1.78, 5.76 and 2.59 Gy/Bq in the nucleus of Pc-3, MCF7 and MDA-MB231 correspondingly

  9. The international protocol for the dosimetry of external radiotherapy beams based on standards of absorbed dose to water

    An International Code of Practice (CoP, or dosimetry protocol) for external beam radiotherapy dosimetry based on standards of absorbed dose to water has been published by the IAEA on behalf of IAEA, WHO, PAHO and ESTRO. The CoP provides a systematic and internationally unified approach for the determination of the absorbed dose to water in reference conditions with radiotherapy beams. The development of absorbed-dose-to-water standards for high-energy photons and electrons offers the possibility of reducing the uncertainty in the dosimetry of radiotherapy beams. Many laboratories already provide calibrations at the radiation quality of 60Co gamma-rays and some have extended calibrations to high-energy photon and electron beams. The dosimetry of kilovoltage x-rays, as well as that of proton and ion beams can also be based on these standards. Thus, a coherent dosimetry system based on the same formalism is achieved for practically all radiotherapy beams. The practical use of the CoP as simple. The document is formed by a set of different CoPs for each radiation type, which include detailed procedures and worksheets. All CoPs are based on ND,w chamber calibrations at a reference beam quality Qo, together with radiation beam quality correction factors kQ preferably measured directly for the user's chamber in a standards laboratory. Calculated values of kQ are provided together with their uncertainty estimates. Beam quality specifiers are 60Co, TPR20,10 (high-energy photons), R50 (electrons), HVL and kV (x-rays) and Rres (protons and ions)

  10. Inhibiting the Aurora B Kinase Potently Suppresses Repopulation During Fractionated Irradiation of Human Lung Cancer Cell Lines

    Sak, Ali, E-mail: ali.sak@uni-due.de [Department of Radiotherapy, West German Cancer Centre (WTZ), University Hospital Essen, University Duisburg-Essen, Essen (Germany); Stuschke, Martin; Groneberg, Michael; Kuebler, Dennis; Poettgen, Christoph [Department of Radiotherapy, West German Cancer Centre (WTZ), University Hospital Essen, University Duisburg-Essen, Essen (Germany); Eberhardt, Wilfried E.E. [Department of Medicine (Cancer Research), West German Cancer Centre (WTZ), University Hospital Essen, University Duisburg-Essen, Essen (Germany)

    2012-10-01

    Purpose: The use of molecular-targeted agents during radiotherapy of non-small-cell lung cancer (NSCLC) is a promising strategy to inhibit repopulation, thereby improving therapeutic outcome. We assessed the combined effectiveness of inhibiting Aurora B kinase and irradiation on human NSCLC cell lines in vitro. Methods and Materials: NSCLC cell lines were exposed to concentrations of AZD1152-hydroxyquinazoline pyrazol anilide (AZD1152-HQPA) inhibiting colony formation by 50% (IC50{sub clone}) in combination with single dose irradiation or different fractionation schedules using multiple 2-Gy fractions per day up to total doses of 4-40 Gy. The total irradiation dose required to control growth of 50% of the plaque monolayers (TCD50) was determined. Apoptosis, G2/M progression, and polyploidization were also analyzed. Results: TCD50 values after single dose irradiation were similar for the H460 and H661 cell lines with 11.4 {+-} 0.2 Gy and 10.7 {+-} 0.3 Gy, respectively. Fractionated irradiation using 3 Multiplication-Sign 2 Gy/day, 2 Multiplication-Sign 2 Gy/day, and 1 Multiplication-Sign 2 Gy/day schedules significantly increased TCD50 values for both cell lines grown as plaque monolayers with increasing radiation treatment time. This could be explained by a repopulation effect per day that counteracts 75 {+-} 8% and 27 {+-} 6% of the effect of a 2-Gy fraction in H460 and H661 cells, respectively. AZD1152-HQPA treatment concomitant to radiotherapy significantly decreased the daily repopulation effect (H460: 28 {+-} 5%, H661: 10 {+-} 4% of a 2-Gy fraction per day). Treatment with IC50{sub clone} AZD1152-HPQA did not induce apoptosis, prolong radiation-induced G2 arrest, or delay cell cycle progression before the spindle check point. However, polyploidization was detected, especially in cell lines without functional p53. Conclusions: Inhibition of Aurora B kinase with low AZD1152-HQPA concentrations during irradiation of NSCLC cell lines affects repopulation during

  11. Inhibiting the Aurora B Kinase Potently Suppresses Repopulation During Fractionated Irradiation of Human Lung Cancer Cell Lines

    Purpose: The use of molecular-targeted agents during radiotherapy of non-small-cell lung cancer (NSCLC) is a promising strategy to inhibit repopulation, thereby improving therapeutic outcome. We assessed the combined effectiveness of inhibiting Aurora B kinase and irradiation on human NSCLC cell lines in vitro. Methods and Materials: NSCLC cell lines were exposed to concentrations of AZD1152-hydroxyquinazoline pyrazol anilide (AZD1152-HQPA) inhibiting colony formation by 50% (IC50clone) in combination with single dose irradiation or different fractionation schedules using multiple 2-Gy fractions per day up to total doses of 4–40 Gy. The total irradiation dose required to control growth of 50% of the plaque monolayers (TCD50) was determined. Apoptosis, G2/M progression, and polyploidization were also analyzed. Results: TCD50 values after single dose irradiation were similar for the H460 and H661 cell lines with 11.4 ± 0.2 Gy and 10.7 ± 0.3 Gy, respectively. Fractionated irradiation using 3 × 2 Gy/day, 2 × 2 Gy/day, and 1 × 2 Gy/day schedules significantly increased TCD50 values for both cell lines grown as plaque monolayers with increasing radiation treatment time. This could be explained by a repopulation effect per day that counteracts 75 ± 8% and 27 ± 6% of the effect of a 2-Gy fraction in H460 and H661 cells, respectively. AZD1152-HQPA treatment concomitant to radiotherapy significantly decreased the daily repopulation effect (H460: 28 ± 5%, H661: 10 ± 4% of a 2-Gy fraction per day). Treatment with IC50clone AZD1152-HPQA did not induce apoptosis, prolong radiation-induced G2 arrest, or delay cell cycle progression before the spindle check point. However, polyploidization was detected, especially in cell lines without functional p53. Conclusions: Inhibition of Aurora B kinase with low AZD1152-HQPA concentrations during irradiation of NSCLC cell lines affects repopulation during radiotherapy. Thus, concomitant Aurora B kinase inhibition and irradiation

  12. Enzyme-activity mutations detected in mice after paternal fractionated irradiation

    (101/E1 X C3H/E1)F1-hybrid male mice were exposed in a 24-h fractionation interval to either 3.0 + 3.0-Gy or 5.1 + 5.1-Gy X-irradiation, and mated to untreated Test-stock females. The offspring were examined for mutations at 7 recessive specific loci and for activity alterations of erythrocyte enzymes controlled presumably by 12 loci. No enzyme-activity mutant was found in 3610 F1-offspring of the control group. In the experimental groups, no mutant was detected in 533 (3.0 + 3.0 Gy) and 173 (5.1 + 5.1 Gy) offspring from postspermatogonial germ cells treated. After treatment of spermatogonia, 1 mutant in 3388 F1-offspring of the 3.0 + 3.0-Gy group, and 5 mutants in 3187 F1 offspring of the 5.1 + 5.1-Gy group were found. The mutants were all genetically confirmed. The frequency (expressed as mutants/locus/gamete) of enzyme-activity mutations is 2 (5.1 + 5.1-Gy group) to 10 (3.0 + 3.0-Gy group) times lower than the frequency of recessive specific-locus mutations. (Auth.)

  13. Haemopoiesis in murine bone marrow and spleen after fractionated irradiation and repeated bone marrow transplantation. II

    Granulopoiesis was studied in mice repeatedly exposed to doses of 3 Gy of 60Co γ-rays at 4-day intervals up to a total dose of 24 Gy on the basis of total bone marrow cellularity follow-up and analysis of myelograms and splenograms. Half the number of the mice received lO6 nuclear cells of syngeneic bone marrow after each fractional radiation dose. After an initial steep decrease, the number of granuloid cells in the spleen increased about 30-fold between days 12 and 16 of the experiment (total dose 9 and 12 Gy, respectively). This increase was temporary and between days 20 and 24 (total dose 15 and 18 Gy, respectively) a steep decrease again occurred. At a low level (below 10% of the control value) the granuloid cells remained in the spleens of bone marrow recipients until the end of the experiment (day 37, total dose 24 Gy). The behavior of the granuloid compartment of hemopoiesis thus contrasts with findings in the erythroid compartment (Hofer et al., 1989) when high numbers of erythroid nuclear cells remained in the spleens of bone marrow recipients until the end of the experiment. On the whole, the influence of repeated bone marrow transplantation on granulopoiesis in the bone marrow and spleen is positive. Of the 22 comparisons made between bone marrow recipients and mice only irradiated, 14 differences are statistically significant, always in favor of bone marrow recipients. (author)

  14. Fractionated irradiation-induced EMT-like phenotype conferred radioresistance in esophageal squamous cell carcinoma

    Zhang, Hongfang; Luo, Honglei; Jiang, Zhenzhen; Yue, Jing; Hou, Qiang; Xie, Ruifei; Wu, Shixiu

    2016-01-01

    The efficacy of radiotherapy, one major treatment modality for esophageal squamous cell carcinoma (ESCC) is severely attenuated by radioresistance. Epithelial-to-mesenchymal transition (EMT) is a cellular process that determines therapy response and tumor progression. However, whether EMT is induced by ionizing radiation and involved in tumor radioresistance has been less studied in ESCC. Using multiple fractionated irradiation, the radioresistant esophageal squamous cancer cell line KYSE-150R had been established from its parental cell line KYSE-150. We found KYSE-150R displayed a significant EMT phenotype with an elongated spindle shape and down-regulated epithelial marker E-cadherin and up-regulated mesenchymal marker N-cadherin in comparison with KYSE-150. Furthermore, KYSE-150R also possessed some stemness-like properties characterized by density-dependent growth promotion and strong capability for sphere formation and tumorigenesis in NOD-SCID mice. Mechanical studies have revealed that WISP1, a secreted matricellular protein, is highly expressed in KYSE-150R and mediates EMT-associated radioresistance both in ESCC cells and in xenograft tumor models. Moreover, WISP1 has been demonstrated to be closely associated with the EMT phenotype observed in ESCC patients and to be an independent prognosis factor of ESCC patients treated with radiotherapy. Our study highlighted WISP1 as an attractive target to reverse EMT-associated radioresistance in ESCC and can be used as an independent prognostic factor of patients treated with radiotherapy. PMID:27125498

  15. Marrow transplantation for leukemia following fractionated total body irradiation. A comparative trial of methotrexate and cyclosporine

    Fifty-six patients, 30-47 yr of age, with leukemia in relapse received allogeneic marrow transplants from HLA-identical siblings. All patients were treated with cyclophosphamide (120 mg/kg) and 7 daily fractions of 2.25 Gy of total body irradiation (TBI) for seven consecutive days. Nine patients (16%) are currently alive, free of disease, 324-845 days from transplantation. Actuarial relapse and survival rates at 2 yr were 56% and 9.5% respectively. These data were not remarkably different from those in previous studies using 10 Gy of TBI administered as a single dose. Thirty patients were randomized to receive methotrexate (MTX) and 26 to receive cyclosporine (CSP) as postgrafting prophylaxis for acute graft-versus-host disease (GVHD). Probability of developing significant acute GVHD by day 100 post-transplant was 71% for patients in the MTX group and 45% for patients in the CSP group (p<0.05). Probability of relapse was 37% for patients in the MTX group and 70% for patients in the CSP group (p<0.05). Transplant-related deaths were more frequent in the MTX group and leukemic deaths more frequent in the CSP group although this may have been related to an uneven distribution of high-risk patients. Long term disease-free survival was comparable. (author)

  16. The content and UV-Vis absorbances of bog peat organic matter fractions (Divčivare, Serbia

    Petrović Petar G.

    2015-01-01

    Full Text Available This paper presents peat soil organic matter characteristics at Divčibare Mountain (950 m a.s.l, mountain climate. Excessive wetting is caused by groundwater and floods, and plant litter originates from hydrophilic vegetation. An investigation was aimed at determining the correlation between organic matter characteristics (humification degree, stability and bioavailability with factors of soil formation and the most important physico-chemical characteristics of peat. Peat is mild acid and has a low base saturation. The content of organic matter is higher than 60% at depth of 40−80 cm, and higher than 40% at depths of 0−40 and 80−105 cm, respectively. Investigated peat had sapric characteristics. A content of humic acids in total organic matter indicates its unequal humification degree within profile, moderate to high at depth of 0−40 cm, low at 40−80-cm depth, and very low beneath 80 cm. A value of Ch/Cf ratio indicates high humus stability up to 80 cm where it has humate-type humus, while below 80 cm humus is the humatefulvate type. A low content of fractions separated with 0.1N cold H2SO4, and cold and hot water, points out a low bioavailability of organic matter through whole soil profile. UV-Vis indices indicate a low humification degree of humic acids (increased to 80-cm depth, and a very low humification degree of fulvic acids (variable, the highest at 60−80-cm depth. Overall results indicate that particle size of mineral fraction, soil reaction, and cation exchange capacity had no significant impact on organic matter characteristics. Soil moisture content, that is alterations of oxido-reductive conditions throughout soil profile had the crucial impact on peat organic matter characteristics.

  17. The influence of fractionated thymocytes of intact and irradiated mice on restoration of CFUs content in bone marrow after sublethal irradiation

    In studying the influence of thymocytes fractionated by their size in the ficoll density gradient on the CFUs content of the irradiated mouse bone marrow, two subpolations of T-cells were isolated; the administration of the first thymocyte subpopulation decreased the CFUs content during the postirradiation recovery period while thymocytes of the second subpopulation increased the content of CFUs in the bone marrow. When thymocytes of mice exposed to low-level radiation were separated a considerable stimulatory effect was produced by certain tthymus cell fractions on the number of CFUs in the bone marrow of exposed recipients; no inhibitory effect was registered

  18. A framework for consistent estimation of leaf area index, fraction of absorbed photosynthetically active radiation, and surface albedo from MODIS time-series data

    Xiao, Zhiqiang; Liang, Shunlin; Wang, Jindi;

    2015-01-01

    model and the MODIS surface reflectance data. The estimated LAI values were then input into the ACRM to calculate the surface albedo and the fraction of absorbed photosynthetically active radiation (FAPAR). For snow-covered areas, the surface albedo was calculated as the underlying vegetation canopy...... albedo plus the weighted distance between the underlying vegetation canopy albedo and the albedo over deep snow. The LAI/FAPAR and surface albedo values estimated using this framework were compared with MODIS collection 5 eight-day 1-km LAI/FAPAR products (MOD15A2) and 500-m surface albedo product (MCD43......-surface parameter profiles from MODIS time-series reflectance data even if some of the reflectance data are contaminated by residual cloud or are missing and that the retrieved LAI, FAPAR, and surface albedo values are physically consistent. The root mean square errors of the retrieved LAI, FAPAR, and surface...

  19. Glycolysis-related gene induction and ATP reduction during fractionated irradiation. Markers for radiation responsiveness of human tumor xenografts

    Goetze, K.; Meyer, S.S.; Mueller-Klieser, W. [University Medical Center Mainz Univ. (Germany). Inst. of Physiology and Pathophysiology; Yaromina, A. [Technical Univ. Dresden (Germany). OncoRay - National Center for Radiation Research in Oncology; Zips, D. [University Hospital Tuebingen (Germany). Dept. of Radiation Oncology; Baumann, M. [Technical Univ. Dresden (Germany). OncoRay - National Center for Radiation Research in Oncology; University Hospital Dresden Technical Univ. Dresden (Germany). Dept. of Radiation Oncology

    2013-09-15

    Background and purpose: Lactate was previously shown to be a prognostic but not a predictive pre-therapeutic marker for radiation response of tumor xenografts. We hypothesize that metabolic changes during fractionated irradiation may restrict the predictiveness of lactate regarding tumor radiosensitivity. Materials and methods: Tumor xenografts were generated in nude mice by implanting 4 head and neck squamous cell carcinoma lines with different sensitivities to fractionated irradiation. Tumors were irradiated with up to 15 fractions of 2 Gy over a period of 3 weeks, and ATP and lactate levels were measured in vital tumor areas with induced metabolic bioluminescence imaging. Corresponding changes in mRNA expression of glycolysis-related genes were determined by quantitative RT-PCR. Results: Lactate content decreased significantly in 3 out of 4 cell lines in the course of irradiation showing no correlation with cell line-specific radiosensitivity. Radiation-induced changes in ATP levels and glycolysis-related mRNA expression, however, only occurred in radiosensitive or intermediately radioresistant xenografts, whereas these parameters remained unchanged in radioresistant tumors. Conclusion: Sensitivity-related differences in the transcriptional response of tumors to radiotherapy may be exploited in the clinic for better individualization of tumor treatment. (orig.)

  20. The effect of the number of fractions of cranial irradiation on growth in children with acute lymphoblastic leukaemia

    Growth was documented over a period of 7 years in all long-term survivors treated for acute lymphoblastic leukaemia (ALL) with the DAL-70- and BFM-70-protocol. Normal growth was documented in patients of the DAL-70-protocol during and after therapy. In contrast, in children treated with the BFM-70-protocol the mean height standard deviation score (SDS) decreased significantly from 1.21 SDS prior to therapy to 0.80 SDS at the end of therapy and remained unchanged thereafter. Prophylatic cranial irradiation was given in total doses of 15 to 30 Gy. Ten children of the DAL-70- and 20 children of the BFM-70-protocol received 24 Gy of cranial irradiation. No significant change in height-SDS was observed in any patients of the DAL-70- and in 8 patients of the BFM-70-group, who received 24 Gy of cranial irradiation on 16-26 fractions. Adult height in 7 girls and 6 boys was normal and 3.15 cm and 5.06 cm above target height. In the remaining 12 patients of the BFM-70-protocol the total dose of 24 Gy of cranial irradiation was applied in 11-14 fractions. Their height-SDS had fallen significantly from 1.24 SDS before to 0.66 SDS at the end of therapy. Adult height in 4 girls and 6 boys was also normal, but the height increase was comparatively smaller, -2.20 cm below target height in the girls and 1.91 cm above in the boys. We conclude, that the loss of height-SDS in patients with ALL receiving 24 Gy of cranial irradiation is most probably due to the number of fractions of irradiation and not to the total radiation dose or the type of chemotherapy

  1. Hypo-fractionated whole breast irradiation: Pro and cons; Irradiation hypofractionnee dans le cancer du sein: pour ou contre?

    Cutuli, B. [Institut du cancer Courlancy, 38, rue de Courlancy, 51100 Reims (France); Fourquet, A. [Institut Curie, 26, rue d' Ulm, 75005 Paris (France)

    2011-10-15

    The continuous increase of breast cancer (BC) incidence, the logistic constraints of the protracted standard 5-week radiations regimen have led to test short hypo-fractionated whole breast radiation therapy schemes. Three prospective randomized trials and a pilot trial have been published. Large numbers of patients were included, with follow-up duration ranging from 5 to 12 years. The conclusions of these trials were similar, showing local control and toxicity equivalent to those of the standard regimen, and supporting the use of three schemes: 42.5 Gy/16 fractions/3 weeks, 40 Gy/15 fractions/3 weeks or 41.6 Gy/13 fractions/5 weeks. However, the patients in these trials had favourable prognostic factors, were treated to the breast only and the boost dose, when indicated, was delivered with a standard fractionation. Hypo-fractionated treatment can only be recommended in patients treated to the breast only, without nodal involvement, with grade < 3 tumours and who are not candidate to chemotherapy. If a boost is to be given, a standard fractionation should be used. Particular care should be taken to avoid heterogeneities leading to high fractional doses to organs at risk (lung and heart). (authors)

  2. Impact of anemia prevention by recombinant human erythropoietin on the sensitivity of xenografted glioblastomas to fractionated irradiation

    Stueben, G.; Poettgen, C.; Knuehmann, K.; Sack, H.; Stuschke, M. [West German Tumor Center, Dept. of Radiotherapy, Univ. Hospital Essen (Germany); Thews, O.; Vaupel, P. [Inst. of Physiology and Pathophysiology, Univ. of Mainz (Germany)

    2003-09-01

    Background: Pronounced oxygen deficiency in tumors which might be caused by a diminished oxygen transport capacity of the blood (e.g., in anemia) reduces the efficacy of ionizing radiation. The aim of this study was to analyze whether anemia prevention by recombinant human erythropoietin (rHuEPO) affects the radiosensitivity of human glioblastoma xenografts during fractionated irradiation. Material and Methods: Anemia was induced by total body irradiation (TBI, 2 x 4 Gy) of mice prior to tumor implantation into the subcutis of the hind leg. In one experimental group, the development of anemia was prevented by rHuEPO (750 U/kg s.c.) given three times weekly starting 10 days prior to TBI. 13 days after tumor implantation (tumor volume approx. 40 mm{sup 3}), fractionated irradiation (4 x 7 Gy, one daily fraction) of the glioblastomas was performed resulting in a growth delay with subsequent regrowth of the tumors. Results: Compared to nonanemic control animals (hemoglobin concentration cHb = 14.7 g/dl), the growth delay in anemic mice (cHb = 9.9 g/dl) was significantly shorter (49 {+-} 5 days vs. 79 {+-} 4 days to reach four times the initial tumor volume) upon fractionated radiation. The prevention of anemia by rHuEPO treatment (cHb = 13.3 g/dl) resulted in a significantly prolonged growth delay (61 {+-} 5 days) compared to the anemia group, even though the growth inhibition found in control animals was not completely achieved. Conclusions: These data indicate that moderate anemia significantly reduces the efficacy of radiotherapy. Prevention of anemia with rHuEPO partially restores the radiosensitivity of xenografted glioblastomas to fractionated irradiation. (orig.)

  3. Impact of anemia prevention by recombinant human erythropoietin on the sensitivity of xenografted glioblastomas to fractionated irradiation

    Background: Pronounced oxygen deficiency in tumors which might be caused by a diminished oxygen transport capacity of the blood (e.g., in anemia) reduces the efficacy of ionizing radiation. The aim of this study was to analyze whether anemia prevention by recombinant human erythropoietin (rHuEPO) affects the radiosensitivity of human glioblastoma xenografts during fractionated irradiation. Material and Methods: Anemia was induced by total body irradiation (TBI, 2 x 4 Gy) of mice prior to tumor implantation into the subcutis of the hind leg. In one experimental group, the development of anemia was prevented by rHuEPO (750 U/kg s.c.) given three times weekly starting 10 days prior to TBI. 13 days after tumor implantation (tumor volume approx. 40 mm3), fractionated irradiation (4 x 7 Gy, one daily fraction) of the glioblastomas was performed resulting in a growth delay with subsequent regrowth of the tumors. Results: Compared to nonanemic control animals (hemoglobin concentration cHb = 14.7 g/dl), the growth delay in anemic mice (cHb = 9.9 g/dl) was significantly shorter (49 ± 5 days vs. 79 ± 4 days to reach four times the initial tumor volume) upon fractionated radiation. The prevention of anemia by rHuEPO treatment (cHb = 13.3 g/dl) resulted in a significantly prolonged growth delay (61 ± 5 days) compared to the anemia group, even though the growth inhibition found in control animals was not completely achieved. Conclusions: These data indicate that moderate anemia significantly reduces the efficacy of radiotherapy. Prevention of anemia with rHuEPO partially restores the radiosensitivity of xenografted glioblastomas to fractionated irradiation. (orig.)

  4. Response of the immune system of monkeys to single and fractionated low-level gamma-irradiation

    A study was made of total and local imminity of two groups of Papio hamadryads subjected to single and ten-fold external gamma-irradiation at a cumulative dose of 5 cGy. It has been shown that with equal dosages changes in the relative and absolute number of lymphocytes in the peripheral blood, the number of circulating T-cells and their functional activity are more pronounced in animals subjected to fractionated irradiation. Both groups exhibited similar disturbances in the functional activity of antibody-dependent kilers and in local immunity of stomatopharynx

  5. Quality assurance program of a respiratory gating irradiation system based on external and internal fiducial markers; Programa de garantia de calidad de un sistema de irradiacion con control respiratorio basado en marcadores fiduciales externos e internos

    Zucca Aparicio, D.; Perez Moreno, J. M.; Fernandez Leton, P.; Garcia Ruiz-Zorrilla, J.; Minambres Moro, A.

    2011-07-01

    Respiratory Gating involves the administration of radiation during treatment delivery within a particular portion of the patients breathing cycle, so the absorbed dose administration with respiratory control techniques requires specific quality control to ensure the correctness of the delivered dose. The establishment of a Quality Control Program (QC) is proposed for the Respiratory Gating based techniques in order to have a better understanding of how this system works and to know its associated dosimetric impact. The influence of the CT acquisition under respiratory motion conditions has been analyzed for the treatment isocenter localization, using internal and external fiducial markers with IGRT techniques that allow the correlation of the isocenter positioning with the phase of the respiratory cycle. Radiation delivery in the presence of intra fraction organ motion causes an averaging or blurring of the static dose distribution over the path of motion increasing the beam penumbra of the radiation field and reducing the therapeutic region when the irradiation is not breath controlled. The feasibility of intensity modulated treatments (IMRT) for both static and dynamic techniques, managed by respiratory control has been tested, demonstrating the possibility of synchronizing the movement of the leaves in the microfluorimeter collimator (mMLC) with the gated beam irradiation. (Author) 45 refs.

  6. Evaluation of onion root tip cell surviving fraction by measuring growing speed irradiated by accelerated heavy ions

    Irradiation of accelerated heavy ions to germinated onion seeds reduced the root growth. The extent of the root shortening increased with the increase of the absorbed dose and with the increase of linear energy transfer (LET). The growing curve looks like converging to a limited curve with increase of the dose and the growing did not stop even at highest dose of 100 Gy. Germinated seeds of green sorgo and alphalfa were investigated for comparison and they showed different dose responses from onion. Growth of green sorgo germs almost stopped at high doses. Growth of alphalfa germs was unaffected by radiations. (author)

  7. CMSAF products Cloud Fraction Coverage and Cloud Type used for solar global irradiance estimation

    Badescu, Viorel; Dumitrescu, Alexandru

    2016-08-01

    Two products provided by the climate monitoring satellite application facility (CMSAF) are the instantaneous Cloud Fractional Coverage (iCFC) and the instantaneous Cloud Type (iCTY) products. Previous studies based on the iCFC product show that the simple solar radiation models belonging to the cloudiness index class n CFC = 0.1-1.0 have rRMSE values ranging between 68 and 71 %. The products iCFC and iCTY are used here to develop simple models providing hourly estimates for solar global irradiance. Measurements performed at five weather stations of Romania (South-Eastern Europe) are used. Two three-class characterizations of the state-of-the-sky, based on the iCTY product, are defined. In case of the first new sky state classification, which is roughly related with cloud altitude, the solar radiation models proposed here perform worst for the iCTY class 4-15, with rRMSE values ranging between 46 and 57 %. The spreading error of the simple models is lower than that of the MAGIC model for the iCTY classes 1-4 and 15-19, but larger for iCTY classes 4-15. In case of the second new sky state classification, which takes into account in a weighted manner the chance for the sun to be covered by different types of clouds, the solar radiation models proposed here perform worst for the cloudiness index class n CTY = 0.7-0.1, with rRMSE values ranging between 51 and 66 %. Therefore, the two new sky state classifications based on the iCTY product are useful in increasing the accuracy of solar radiation models.

  8. The Suitability of Absorbable Mesh Insertion for Oncoplastic Breast Surgery in Patients with Breast Cancer Scheduled to Be Irradiated

    Kim, Taehyun; Cho, Heunglae

    2013-01-01

    Purpose The objective of this study was to investigate the influence of radiotherapy on the cosmetic outcome after immediate breast reconstruction using an absorbable mesh in breast cancer. Methods From July 2008 to July 2009, 35 breast cancer patients who received immediate breast reconstruction with absorbable mesh insertion at the time of breast conserving surgery followed by radiotherapy were retrospectively studied. Results In 91% of cases there was an excellent or good cosmetic outcome ...

  9. Impact of fractionated local irradiation on lung metastasis in H22-bearing mice and exploration of its mechanism

    Objective: To study the impact of local fractionated irradiation on lung metastasis in H22-bearing ice, and to explore its mechanism involved. Methods: Subcutaneous transplantation tumor model bearing with H22 was established. Mice were divided into three groups as healthy control, tumor control and irradiation groups. The size of subcutaneous tumors was measured and lung metastasis was observed. The expressions of PCNA, VEGF and MVD were detected immunohistochemically. The plasma levels of CD4 and CD8 were determined by using flow cytometry. Results: The tumor size in irradiated group was smaller than that in tumor control group. The tumor inhibition rate in irradiated group was 30%. Lung metastasis in irradiated group was more severe than that in tumor control group (χ2=8.31, 4.48, 9.60, P<0.05). The expressions of PCNA, VEGF and MVD in two groups were statistically different (t=23.78, -2.47, -6.43, P<0.05). The levels of CD4 and CD8 in irradiated group were statistically different compared to healthy control group (t=4.72 and 3.31, P<0.05). Conclusions: For the H22 model, radiation might inhibit the local transplantation tumor, but increase the risk of lung metastasis. (authors)

  10. Experiences of an international trade action with irradiated onions between GDR and Hungary

    Extensive work has been carried out in the field of food irradiation in the GDR and Hungary in recent years. The irradiation of onions for sprout inhibition has reached a commercial stage in the GDR of more than 5,000 tons in 1986. The export of onions is the first example of international trade in irradiated food between socialist countries. Experiences of this trade is presented in the paper. Results of quality control of the bulbs (losses in weight an quality) after an intermediate storage period are discussed. Hungarian consumer reactions to irradiated onions is also evaluated. (author)