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Sample records for high-dose three-dimensional radiation

  1. Global Gene Expression Responses to Low- or High-Dose Radiation in a Human Three-Dimensional Tissue Model

    PubMed Central

    Mezentsev, Alexandre; Amundson, Sally A.

    2011-01-01

    Accumulating data suggest that the biological responses to high and low doses of radiation are qualitatively different, necessitating the direct study of low-dose responses to better understand potential risks. Most such studies have used two-dimensional culture systems, which may not fully represent responses in three-dimensional tissues. To gain insight into low-dose responses in tissue, we have profiled global gene expression in EPI-200, a three-dimensional tissue model that imitates the structure and function of human epidermis, at 4, 16 and 24 h after exposure to high (2.5 Gy) and low (0.1 Gy) doses of low-LET protons. The most significant gene ontology groups among genes altered in expression were consistent with effects observed at the tissue level, where the low dose was associated with recovery and tissue repair, while the high dose resulted in loss of structural integrity and terminal differentiation. Network analysis of the significantly responding genes suggested that TP53 dominated the response to 2.5 Gy, while HNF4A, a novel transcription factor not previously associated with radiation response, was most prominent in the low-dose response. HNF4A protein levels and phosphorylation were found to increase in tissues and cells after low- but not high-dose irradiation. PMID:21486161

  2. Fast, three-dimensional, MR Imaging for polymer gel dosimetric applications involving high dose and steep dose gradients

    NASA Astrophysics Data System (ADS)

    Sandilos, Panagiotis; Baras, Panagiotis; Georgiou, Evangelos; Dardoufas, Konstantinos; Karaiskos, Pantelis; Papagiannis, Panagiotis; Paschalis, Theodoros; Tatsis, Elias; Torrens, Michael; Vlahos, Lampros

    2006-12-01

    Polymer gels constitute water equivalent integrating detectors, which, combined with magnetic resonance imaging (MRI), can provide accurate three dimensional (3D) dose distributions in contemporary radiotherapy applications where the small field dimensions and steep dose gradients induce limitations to conventional dosimeters. One of the main obstacles for adapting the method for routine use in the clinical setting is the cost effectiveness of the MRI readout method. Currently, optimized Carr-Purcell-Meiboom-Gill (CPMG) multiple spin echo imaging pulse sequences are commonly used which however result in long imaging times. This work evaluates the efficiency of 3D, dual-echo, k-space segmented turbo spin echo (TSE) scanning sequences for accurate dosimetry with sub-millimetre spatial resolution in strenuous radiation therapy applications. PABIG polymer gel dosimeters were irradiated with an 192Ir High Dose Rate brachytherapy source, the 4 mm and 8 mm collimator helmets of a gamma knife unit and a custom made x-knife collimator of 1 cm diameter. Profile and dose distribution measurements using TSE are benchmarked against corresponding findings obtained by the commonly used, but time consuming, CPMG sequence as well as treatment planning calculations, Monte Carlo (MC) simulations and film measurements. The implementation of a high Turbo factor was found to provide comparable accuracy, allowing a 64-fold MRI scan acceleration compared to conventional multi-echo sequences. The availability of TSE sequences in typical MRI installations greatly facilitates the introduction of polymer gel dosimetry in the clinical environment as a practicable tool for the determination of full 3D dose distributions in contemporary radiotherapy applications.

  3. Radiative transfer for a three-dimensional raining cloud

    NASA Technical Reports Server (NTRS)

    Haferman, J. L.; Krajewski, W. F.; Smith, T. F.; Sanchez, A.

    1993-01-01

    Satellite-sensor-based microwave brightness temperatures for a three-dimensional raining cloud over a reflecting surface are computed by using a radiative transfer model based on the discrete-ordinates solution procedure. The three-dimensional model applied to a plane layer is validated by comparison with results from a one-dimensional model that is available in the literature. Results examining the effects of cloud height, rainfall rate, surface reflectance, rainfall footprint area, and satellite viewing position on one- and three-dimensional brightness temperature calculations are reported. The numerical experiments indicate that, under certain conditions, three-dimensional effects are significant in the analysis of satellite-sensor-based rainfall retrieval algorithms. The results point to the need to consider carefully three-dimensional effects as well as surface reflectance effects when interpreting satellite-measured radiation data.

  4. Radiative transfer for a three-dimensional raining cloud

    NASA Technical Reports Server (NTRS)

    Haferman, J. L.; Krajewski, W. F.; Smith, T. F.; Sanchez, A.

    1993-01-01

    Satellite-sensor-based microwave brightness temperatures for a three-dimensional raining cloud over a reflecting surface are computed by using a radiative transfer model based on the discrete-ordinates solution procedure. The three-dimensional model applied to a plane layer is validated by comparison with results from a one-dimensional model that is available in the literature. Results examining the effects of cloud height, rainfall rate, surface reflectance, rainfall footprint area, and satellite viewing position on one- and three-dimensional brightness temperature calculations are reported. The numerical experiments indicate that, under certain conditions, three-dimensional effects are significant in the analysis of satellite-sensor-based rainfall retrieval algorithms. The results point to the need to consider carefully three-dimensional effects as well as surface reflectance effects when interpreting satellite-measured radiation data.

  5. Definitive three-dimensional high-dose-rate brachytherapy for inoperable endometrial cancer.

    PubMed

    Draghini, Lorena; Maranzano, Ernesto; Casale, Michelina; Trippa, Fabio; Anselmo, Paola; Arcidiacono, Fabio; Fabiani, Stefania; Italiani, Marco; Chirico, Luigia; Muti, Marco

    2017-04-01

    To report our experience on high-dose-rate brachytherapy (HDR-BT) in patients with stage I-III endometrial cancer unfit to surgery. Seventeen patients underwent HDR-BT as definitive treatment. Median age was 79 years (range, 60-95), median Karnofsky performance status 90% (range, 60-100). Histology was endometrial adenocarcinoma in 14 (82%), and non-endometrial in 3 (18%) patients. In 15 (88%) patients, clinical stage was I and in remaining 2 (12%) was III. All patients were evaluated with computed tomography (CT) and endometrial biopsy. Using the Fletcher applicator, a CT-based planning HDR-BT was delivered. Local control (LC) was obtained when there was an interruption of vaginal bleeding in absence of CT-imaging progression. Fourteen patients underwent HDR-BT alone and three external beam radiotherapy (EBRT) combined with HDR-BT. All patients had a clinical LC, after a median follow-up of 53 months (range, 6-131), 3 and 6 years LC rates were 86% and 69%, respectively. Cancer specific survival (CSS) at 1, 2, and 6 years was 93%, 85%, and 85%, respectively. Age, stage, dose, and type of radiotherapy did not result significant prognostic factors for LC and CSS. Only histology significantly influenced LC: for high-risk histology (i.e., non-endometrial carcinoma or grade [G] 3 endometrial adenocarcinoma) LC was 73% at 1 year and 36% at 6 years; for low-risk histology (i.e., G1-2 endometrial adenocarcinoma) was 100% at 1 and 6 years (p = 0.05). Two (12%) patients had G2 acute toxicity and two others (12%) G1 late toxicity. Although some limitations of our analysis (relatively few number of patients recruited, retrospective evaluation, and consequent suboptimal patient selection), it confirms effectiveness and safety of definitive HDR-BT for medically inoperable stage I-III endometrial cancer. The best LC was obtained in stage I low-risk histology.

  6. Definitive three-dimensional high-dose-rate brachytherapy for inoperable endometrial cancer

    PubMed Central

    Draghini, Lorena; Casale, Michelina; Trippa, Fabio; Anselmo, Paola; Arcidiacono, Fabio; Fabiani, Stefania; Italiani, Marco; Chirico, Luigia; Muti, Marco

    2017-01-01

    Purpose To report our experience on high-dose-rate brachytherapy (HDR-BT) in patients with stage I-III endometrial cancer unfit to surgery. Material and methods Seventeen patients underwent HDR-BT as definitive treatment. Median age was 79 years (range, 60-95), median Karnofsky performance status 90% (range, 60-100). Histology was endometrial adenocarcinoma in 14 (82%), and non-endometrial in 3 (18%) patients. In 15 (88%) patients, clinical stage was I and in remaining 2 (12%) was III. All patients were evaluated with computed tomography (CT) and endometrial biopsy. Using the Fletcher applicator, a CT-based planning HDR-BT was delivered. Local control (LC) was obtained when there was an interruption of vaginal bleeding in absence of CT-imaging progression. Results Fourteen patients underwent HDR-BT alone and three external beam radiotherapy (EBRT) combined with HDR-BT. All patients had a clinical LC, after a median follow-up of 53 months (range, 6-131), 3 and 6 years LC rates were 86% and 69%, respectively. Cancer specific survival (CSS) at 1, 2, and 6 years was 93%, 85%, and 85%, respectively. Age, stage, dose, and type of radiotherapy did not result significant prognostic factors for LC and CSS. Only histology significantly influenced LC: for high-risk histology (i.e., non-endometrial carcinoma or grade [G] 3 endometrial adenocarcinoma) LC was 73% at 1 year and 36% at 6 years; for low-risk histology (i.e., G1-2 endometrial adenocarcinoma) was 100% at 1 and 6 years (p = 0.05). Two (12%) patients had G2 acute toxicity and two others (12%) G1 late toxicity. Conclusions Although some limitations of our analysis (relatively few number of patients recruited, retrospective evaluation, and consequent suboptimal patient selection), it confirms effectiveness and safety of definitive HDR-BT for medically inoperable stage I-III endometrial cancer. The best LC was obtained in stage I low-risk histology. PMID:28533799

  7. Radiative Instabilities in Three-Dimensional Astrophysical Masers

    NASA Technical Reports Server (NTRS)

    Scappaticci, Gerardo A.; Watson, William D.

    1995-01-01

    Inherent instabilities in the radiative transfer for astrophysical masers have been recognized and calculated in the linear maser idealization in our previous investigations. The same instabilities are now shown to occur in the more realistic, three-dimensional geometries. Fluctuations in the emergent flux result and may be related to the observed fluctuations in the radiative flux from the 1665 MHz OH masers that have been reported to occur on timescales as short as 1000 s. The time-dependent differential equations of radiative transfer are solved numerically for three-dimensional astrophysical masers. Computations are performed for spherical and elongated (rectangular parallelepiped) geometries.

  8. Radiation hardness of three-dimensional polycrystalline diamond detectors

    SciTech Connect

    Lagomarsino, Stefano Sciortino, Silvio; Bellini, Marco; Corsi, Chiara; Cindro, Vladimir; Kanxheri, Keida; Servoli, Leonello; Morozzi, Arianna; Passeri, Daniele; Schmidt, Christian J.

    2015-05-11

    The three-dimensional concept in particle detection is based on the fabrication of columnar electrodes perpendicular to the surface of a solid state radiation sensor. It permits to improve the radiation resistance characteristics of a material by lowering the necessary bias voltage and shortening the charge carrier path inside the material. If applied to a long-recognized exceptionally radiation-hard material like diamond, this concept promises to pave the way to the realization of detectors of unprecedented performances. We fabricated conventional and three-dimensional polycrystalline diamond detectors, and tested them before and after neutron damage up to 1.2 ×10{sup 16 }cm{sup −2}, 1 MeV-equivalent neutron fluence. We found that the signal collected by the three-dimensional detectors is up to three times higher than that of the conventional planar ones, at the highest neutron damage ever experimented.

  9. High dose bystander effects in spatially fractionated radiation therapy

    PubMed Central

    Asur, Rajalakshmi; Butterworth, Karl T.; Penagaricano, Jose A.; Prise, Kevin M.; Griffin, Robert J.

    2014-01-01

    Traditional radiotherapy of bulky tumors has certain limitations. Spatially fractionated radiation therapy (GRID) and intensity modulated radiotherapy (IMRT) are examples of advanced modulated beam therapies that help in significant reductions in normal tissue damage. GRID refers to the delivery of a single high dose of radiation to a large treatment area that is divided into several smaller fields, while IMRT allows improved dose conformity to the tumor target compared to conventional three-dimensional conformal radiotherapy. In this review, we consider spatially fractionated radiotherapy approaches focusing on GRID and IMRT, and present complementary evidence from different studies which support the role of radiation induced signaling effects in the overall radiobiological rationale for these treatments. PMID:24246848

  10. Three-dimensional radiation transfer modeling in a dicotyledon leaf

    NASA Astrophysics Data System (ADS)

    Govaerts, Yves M.; Jacquemoud, Stéphane; Verstraete, Michel M.; Ustin, Susan L.

    1996-11-01

    The propagation of light in a typical dicotyledon leaf is investigated with a new Monte Carlo ray-tracing model. The three-dimensional internal cellular structure of the various leaf tissues, including the epidermis, the palisade parenchyma, and the spongy mesophyll, is explicitly described. Cells of different tissues are assigned appropriate morphologies and contain realistic amounts of water and chlorophyll. Each cell constituent is characterized by an index of refraction and an absorption coefficient. The objective of this study is to investigate how the internal three-dimensional structure of the tissues and the optical properties of cell constituents control the reflectance and transmittance of the leaf. Model results compare favorably with laboratory observations. The influence of the roughness of the epidermis on the reflection and absorption of light is investigated, and simulation results confirm that convex cells in the epidermis focus light on the palisade parenchyma and increase the absorption of radiation.

  11. Prospective Clinical Trial of Bladder Filling and Three-Dimensional Dosimetry in High-Dose-Rate Vaginal Cuff Brachytherapy

    SciTech Connect

    Stewart, Alexandra J.; Cormack, Robert A.; Lee, Hang; Xiong Li; Hansen, Jorgen L.; O'Farrell, Desmond A.; Viswanathan, Akila N.

    2008-11-01

    Purpose: To investigate the effect of bladder filling on dosimetry and to determine the best bladder dosimetric parameter for vaginal cuff brachytherapy. Methods and Materials: In this prospective clinical trial, a total of 20 women underwent vaginal cylinder high-dose-rate brachytherapy. The bladder was full for Fraction 2 and empty for Fraction 3. Dose-volume histogram and dose-surface histogram values were generated for the bladder, rectum, and urethra. The midline maximal bladder point (MBP) and the midline maximal rectal point were recorded. Paired t tests, Pearson correlations, and regression analyses were performed. Results: The volume and surface area of the irradiated bladder were significantly smaller when the bladder was empty than when full. Of the several dose-volume histogram and dose-surface histogram parameters evaluated, the bladder maximal dose received by 2 cm{sup 3} of tissue, volume of bladder receiving {>=}50% of the dose, volume of bladder receiving {>=}70% of the dose, and surface area of bladder receiving {>=}50% of the dose significantly predicted for the difference between the empty vs. full filling state. The volume of bladder receiving {>=}70% of the dose and the maximal dose received by 2 cm{sup 3} of tissue correlated significantly with the MBP. Bladder filling did not alter the volume or surface area of the rectum irradiated. However, an empty bladder did result in the nearest point of bowel being significantly closer to the vaginal cylinder than when the bladder was full. Conclusions: Patients undergoing vaginal cuff brachytherapy treated with an empty bladder have a lower bladder dose than those treated with a full bladder. The MBP correlated well with the volumetric assessments of bladder dose and provided a noninvasive method for reporting the MBP dose using three-dimensional imaging. The MBP can therefore be used as a surrogate for complex dosimetry in the clinic.

  12. High-dose-rate Three-dimensional Conformal Radiotherapy Combined with Active Breathing Control for Stereotactic Body Radiotherapy of Early-stage Non-small-cell Lung Cancer.

    PubMed

    Wang, Ruozheng; Yin, Yong; Qin, Yonghui; Yu, Jinming

    2015-12-01

    The purpose of this study was to evaluate the feasibility and benefits of using high-dose-rate three-dimensional conformal radiotherapy (3D-CRT) combined with active breathing control (ABC) for stereotactic body radiotherapy (SBRT) of patients with early-stage non-small-cell lung cancer (NSCLC). Eight patients with early-stage NSCLC underwent CT scans under standard free-breathing (FB) and moderately deep inspiration breath-hold (mDIBH) with ABC. Two high-dose-rate 3D-CRT plans (1000 Mu/min) were designed based on the CT scans with FB and mDIBH. The maximal dose (D1%), minimal dose (D99%), conformity index (CI), and homogeneity index (HI) of the planning target volume (PTV), and dose-volume indices of the organs at risk between each plan were compared. The mean PTV volume decreased from 158.04 cm(3) with FB to 76.90 cm(3) with mDIBH (p < 0.05). When mDIBH was used, increases in the affected lung volume (by 47%), contralateral lung volume (by 55%), and total lung volume (by 50%) were observed compared to FB (p < 0.05). The V5-V40 of the affected lung (Vx represented the percentage volume of organs receiving at least the x Gy), V5-V40 and the mean dose for the total lung, V5-V40 and mean dose of the chest wall, and the maximum dose of the spinal cord were less for mDIBH than FB (p < 0.05). There were no significant differences in CI, HI, D1%, or D99% for the PTV between the plans. In conclusion, high-dose-rate 3D-CRT combined with ABC reduced the radiation dose to the lungs and chest wall without affecting the dose distribution in SBRT of early-stage NSCLC patients.

  13. TWILIGHT: A Cellular Framework for Three-Dimensional Radiative Transfer

    NASA Astrophysics Data System (ADS)

    Khatami, David; Madore, Barry

    2015-01-01

    We describe a new framework for solving three-dimensional radiative transfer of arbitrary geometries, including a full characterisation of the wavelength-dependent anisotropic scattering, absorption, and thermal reemission of light by dust. By adopting a cellular approach to discretising the light and dust, the problem can be efficiently solved through a fully deterministic iterative process. As a proof of concept we present TWILIGHT, our implementation of the cellular approach, in order to demonstrate and benchmark the new method. TWILIGHT simultaneously renders over one hundred unique images of a given environment with no additional slowdown, enabling a close study of inclination effects of three-dimensional dust geometries. In addition to qualitative rendering tests, TWILIGHT is successfully tested against two Monte-Carlo radiative transfer benchmarks, producing similar brightness profiles at varying inclinations. With the proof-of-concept established, we describe the improvements and current developments underway using the cellular framework, including a technique to resolve the subgrid physics of dust radiative transfer from micron-scale grain models to kiloparsec-sized dust environments.

  14. HERACLES: a three-dimensional radiation hydrodynamics code

    NASA Astrophysics Data System (ADS)

    González, M.; Audit, E.; Huynh, P.

    2007-03-01

    Aims:We present a new three-dimensional radiation hydrodynamics code called HERACLES that uses an original moment method to solve the radiative transfer. Methods: The radiation transfer is modelled using a two-moment model and a closure relation that allows large angular anisotropies in the radiation field to be preserved and reproduced. The radiative equations thus obtained are solved by a second-order Godunov-type method and integrated implicitly by using iterative solvers. HERACLES has been parallelized with the MPI library and implemented in Cartesian, cylindrical, and spherical coordinates. To characterize the accuracy of HERACLES and to compare it with other codes, we performed a series of tests including purely radiative tests and radiation-hydrodynamics ones. Results: The results show that the physical model used in HERACLES for the transfer is fairly accurate in both the diffusion and transport limit, but also for semi-transparent regions. Conclusions: . This makes HERACLES very well-suited to studying many astrophysical problems such as radiative shocks, molecular jets of young stars, fragmentation and formation of dense cores in the interstellar medium, and protoplanetary discs. Appendices are only available in electronic form at http://www.aanda.org

  15. Realistic three-dimensional radiative transfer simulations of observed precipitation

    NASA Astrophysics Data System (ADS)

    Adams, I. S.; Bettenhausen, M. H.

    2013-12-01

    Remote sensing observations of precipitation typically utilize a number of instruments on various platforms. Ground validation campaigns incorporate ground-based and airborne measurements to characterize and study precipitating clouds, while the precipitation measurement constellation envisioned by the Global Precipitation Measurement (GPM) mission includes measurements from differing space-borne instruments. In addition to disparities such as frequency channel selection and bandwidth, measurement geometry and resolution differences between observing platforms result in inherent inconsistencies between data products. In order to harmonize measurements from multiple passive radiometers, a framework is required that addresses these differences. To accomplish this, we have implemented a flexible three-dimensional radiative transfer model. As its core, the radiative transfer model uses the Atmospheric Radiative Transfer Simulator (ARTS) version 2 to solve the radiative transfer equation in three dimensions using Monte Carlo integration. Gaseous absorption is computed with MonoRTM and formatted into look-up tables for rapid processing. Likewise, scattering properties are pre-computed using a number of publicly available codes, such as T-Matrix and DDSCAT. If necessary, a melting layer model can be applied to the input profiles. Gaussian antenna beams estimate the spatial resolutions of the passive measurements, and realistic bandpass characteristics can be included to properly account for the spectral response of the simulated instrument. This work presents three-dimensional simulations of WindSat brightness temperatures for an oceanic rain event sampled by the Tropical Rainfall Measuring Mission (TRMM) satellite. The 2B-31 combined Precipitation Radar / TRMM Microwave Imager (TMI) retrievals provide profiles that are the input to the radiative transfer model. TMI brightness temperatures are also simulated. Comparisons between monochromatic, pencil beam simulations and

  16. EFFICIENT THREE-DIMENSIONAL NLTE DUST RADIATIVE TRANSFER WITH SKIRT

    SciTech Connect

    Baes, Maarten; Verstappen, Joris; De Looze, Ilse; Fritz, Jacopo; Saftly, Waad; Vidal Perez, Edgardo; Stalevski, Marko; Valcke, Sander

    2011-10-01

    We present an updated version of SKIRT, a three-dimensional (3D) Monte Carlo radiative transfer code developed to simulate dusty galaxies. The main novel characteristics of the SKIRT code are the use of a stellar foam to generate random positions, an efficient combination of eternal forced scattering and continuous absorption, and a new library approach that links the radiative transfer code to the DustEM dust emission library. This approach enables a fast, accurate, and self-consistent calculation of the dust emission of arbitrary mixtures of transiently heated dust grains and polycyclic aromatic hydrocarbons, even for full 3D models containing millions of dust cells. We have demonstrated the accuracy of the SKIRT code through a set of simulations based on the edge-on spiral galaxy UGC 4754. The models we ran were gradually refined from a smooth, two-dimensional, local thermal equilibrium (LTE) model to a fully 3D model that includes non-LTE (NLTE) dust emission and a clumpy structure of the dusty interstellar medium. We find that clumpy models absorb UV and optical radiation less efficiently than smooth models with the same amount of dust, and that the dust in clumpy models is on average both cooler and less luminous. Our simulations demonstrate that, given the appropriate use of optimization techniques, it is possible to efficiently and accurately run Monte Carlo radiative transfer simulations of arbitrary 3D structures of several million dust cells, including a full calculation of the NLTE emission by arbitrary dust mixtures.

  17. Radiation dosimetry using three-dimensional optical random access memories

    NASA Technical Reports Server (NTRS)

    Moscovitch, M.; Phillips, G. W.

    2001-01-01

    Three-dimensional optical random access memories (3D ORAMs) are a new generation of high-density data storage devices. Binary information is stored and retrieved via a light induced reversible transformation of an ensemble of bistable photochromic molecules embedded in a polymer matrix. This paper describes the application of 3D ORAM materials to radiation dosimetry. It is shown both theoretically and experimentally, that ionizing radiation in the form of heavy charged particles is capable of changing the information originally stored on the ORAM material. The magnitude and spatial distribution of these changes are used as a measure of the absorbed dose, particle type and energy. The effects of exposure on 3D ORAM materials have been investigated for a variety of particle types and energies, including protons, alpha particles and 12C ions. The exposed materials are observed to fluoresce when exposed to laser light. The intensity and the depth of the fluorescence is dependent on the type and energy of the particle to which the materials were exposed. It is shown that these effects can be modeled using Monte Carlo calculations. The model provides a better understanding of the properties of these materials. which should prove useful for developing systems for charged particle and neutron dosimetry/detector applications. c2001 Published by Elsevier Science B.V.

  18. Radiation dosimetry using three-dimensional optical random access memories

    NASA Technical Reports Server (NTRS)

    Moscovitch, M.; Phillips, G. W.

    2001-01-01

    Three-dimensional optical random access memories (3D ORAMs) are a new generation of high-density data storage devices. Binary information is stored and retrieved via a light induced reversible transformation of an ensemble of bistable photochromic molecules embedded in a polymer matrix. This paper describes the application of 3D ORAM materials to radiation dosimetry. It is shown both theoretically and experimentally, that ionizing radiation in the form of heavy charged particles is capable of changing the information originally stored on the ORAM material. The magnitude and spatial distribution of these changes are used as a measure of the absorbed dose, particle type and energy. The effects of exposure on 3D ORAM materials have been investigated for a variety of particle types and energies, including protons, alpha particles and 12C ions. The exposed materials are observed to fluoresce when exposed to laser light. The intensity and the depth of the fluorescence is dependent on the type and energy of the particle to which the materials were exposed. It is shown that these effects can be modeled using Monte Carlo calculations. The model provides a better understanding of the properties of these materials. which should prove useful for developing systems for charged particle and neutron dosimetry/detector applications. c2001 Published by Elsevier Science B.V.

  19. Evolution of inclined planets in three-dimensional radiative discs

    NASA Astrophysics Data System (ADS)

    Bitsch, B.; Kley, W.

    2011-06-01

    Context. While planets in the solar system only have a low inclination with respect to the ecliptic there is mounting evidence that in extrasolar systems the inclination can be very high, at least for close-in planets. One process to alter the inclination of a planet is through planet-disc interactions. Recent simulations considering radiative transport have shown that the evolution of migration and eccentricity can strongly depend on the thermodynamic state of the disc. So far, this process has only been studied for a few selected planet masses using isothermal discs. Aims: We extend previous studies to investigate the planet-disc interactions of fixed and moving planets on inclined and eccentric orbits. We also analyse the effect of the disc's thermodynamic properties on the orbital evolution of embedded planets in detail. Methods: The protoplanetary disc is modelled as a viscous gas where the internally produced dissipation is transported by radiation. To solve the equations we use an explicit three-dimensional (3D) hydrodynamical code NIRVANA that includes full tensor viscosity, as well as implicit radiation transport in the flux-limited diffusion approximation. To speed up the simulations we apply the FARGO-algorithm in a 3D context. Results: For locally isothermal discs, we confirm previous results and find inclination damping and inward migration for planetary cores. For low inclinations (i ≲ 2H/r), the damping is exponential, while it follows di/dt ∝ i-2 for larger i. For radiative discs, the planetary migration is very limited, as long as their inclination exceeds a certain threshold. If the inclination is damped below this threshold, planetary cores with a mass up to ≈33 MEarth start to migrate outwards, while larger cores migrate inwards right from the start. The inclination is damped for all analysed planet masses. Conclusions: In a viscous disc an initial inclination of embedded planets will be damped for all planet masses. This damping occurs on

  20. THREE-DIMENSIONAL RADIATION TRANSFER IN YOUNG STELLAR OBJECTS

    SciTech Connect

    Whitney, B. A.; Honor, J.; Robitaille, T. P.; Bjorkman, J. E.; Dong, R.; Wolff, M. J.; Wood, K.

    2013-08-15

    We have updated our publicly available dust radiative transfer code (HOCHUNK3D) to include new emission processes and various three-dimensional (3D) geometries appropriate for forming stars. The 3D geometries include warps and spirals in disks, accretion hotspots on the central star, fractal clumping density enhancements, and misaligned inner disks. Additional axisymmetric (2D) features include gaps in disks and envelopes, ''puffed-up inner rims'' in disks, multiple bipolar cavity walls, and iteration of disk vertical structure assuming hydrostatic equilibrium (HSEQ). We include the option for simple power-law envelope geometry, which, combined with fractal clumping and bipolar cavities, can be used to model evolved stars as well as protostars. We include non-thermal emission from polycyclic aromatic hydrocarbons (PAHs) and very small grains, and external illumination from the interstellar radiation field. The grid structure was modified to allow multiple dust species in each cell; based on this, a simple prescription is implemented to model dust stratification. We describe these features in detail, and show example calculations of each. Some of the more interesting results include the following: (1) outflow cavities may be more clumpy than infalling envelopes. (2) PAH emission in high-mass stars may be a better indicator of evolutionary stage than the broadband spectral energy distribution slope; and related to this, (3) externally illuminated clumps and high-mass stars in optically thin clouds can masquerade as young stellar objects. (4) Our HSEQ models suggest that dust settling is likely ubiquitous in T Tauri disks, in agreement with previous observations.

  1. Three-Dimensional Display Of Radiation Therapy Planning

    NASA Astrophysics Data System (ADS)

    Cook, L. T.; Lee, K. R.; Cytacki, E. P.; Dwyer, S. J.

    1987-06-01

    Three-dimensional (3-D) treatment planning has been widely recognized as the ultimate method for radiation therapy for several decades. Recently, interest in developing 3-D treatment planning has been stimulated by the advent of computed tomography (CT), magnetic resonance imaging, and advanced computer technology. A 3-D treatment planning system requires an interactive computer system which is capable of performing the following functions: Demonstration of the tumor volume and normal anatomy in three dimensions, Calculation of the tumor volume, Definition of the target volume, Measurement of the distance and angles from outer surface reference points (e.g., external meatus) to specific anatomic points of interest (e.g., center of tumor), Projection of the spatial relationship between the therapy beam and normal anatomy, and calculation and display of dose distribution in three-dimensions. We have used a commercially available computer display system with a host microcomputer (M68000) to satisfy the above display and interaction requirements except for the calculation of 3-D dose distributions. The system has been applied to several cases which used CT as the imaging modality. A scanning protocol was established which called for contiguous 5mm thick slices from 2 cm above to 2 cm below the skin markers for the designated treatment field. Each patient was scanned in the treatment position, possibly using a fixation device. The outer skin contours, the tumor and adjacent contours were manually traced using a digitizing pen. The surfaces of the skin, the tumor, and normal anatomic structures were reconstructed in the display computer which then allowed a variety of interactions with the data, including beam definition and the real time positioning of the beam. After beam positions were established, the dose distribution within the treatment volume was computed, reconstructed, and then displayed along with the anatomic structures.

  2. A practical three-dimensional dosimetry system for radiation therapy

    SciTech Connect

    Guo Pengyi; Adamovics, John; Oldham, Mark

    2006-10-15

    There is a pressing need for a practical three-dimensional (3D) dosimetry system, convenient for clinical use, and with the accuracy and resolution to enable comprehensive verification of the complex dose distributions typical of modern radiation therapy. Here we introduce a dosimetry system that can achieve this challenge, consisting of a radiochromic dosimeter (PRESAGE trade mark sign ) and a commercial optical computed tomography (CT) scanning system (OCTOPUS trade mark sign ). PRESAGE trade mark sign is a transparent material with compelling properties for dosimetry, including insensitivity of the dose response to atmospheric exposure, a solid texture negating the need for an external container (reducing edge effects), and amenability to accurate optical CT scanning due to radiochromic optical contrast as opposed to light-scattering contrast. An evaluation of the performance and viability of the PRESAGE trade mark sign /OCTOPUS, combination for routine clinical 3D dosimetry is presented. The performance of the two components (scanner and dosimeter) was investigated separately prior to full system test. The optical CT scanner has a spatial resolution of {<=}1 mm, geometric accuracy within 1 mm, and high reconstruction linearity (with a R{sup 2} value of 0.9979 and a standard error of estimation of {approx}1%) relative to independent measurement. The overall performance of the PRESAGE trade mark sign /OCTOPUS system was evaluated with respect to a simple known 3D dose distribution, by comparison with GAFCHROMIC[reg] EBT film and the calculated dose from a commissioned planning system. The 'measured' dose distribution in a cylindrical PRESAGE trade mark sign dosimeter (16 cm diameter and 11 cm height) was determined by optical-CT, using a filtered backprojection reconstruction algorithm. A three-way Gamma map comparison (4% dose difference and 4 mm distance to agreement), between the PRESAGE trade mark sign , EBT and calculated dose distributions, showed full

  3. A practical three-dimensional dosimetry system for radiation therapy.

    PubMed

    Guo, Pengyi; Adamovics, John; Oldham, Mark

    2006-10-01

    There is a pressing need for a practical three-dimensional (3D) dosimetry system, convenient for clinical use, and with the accuracy and resolution to enable comprehensive verification of the complex dose distributions typical of modern radiation therapy. Here we introduce a dosimetry system that can achieve this challenge, consisting of a radiochromic dosimeter (PRESAGE) and a commercial optical computed tomography (CT) scanning system (OCTOPUS). PRESAGE is a transparent material with compelling properties for dosimetry, including insensitivity of the dose response to atmospheric exposure, a solid texture negating the need for an external container (reducing edge effects), and amenability to accurate optical CT scanning due to radiochromic optical contrast as opposed to light-scattering contrast. An evaluation of the performance and viability of the PRESAGE/OCTOPUS, combination for routine clinical 3D dosimetry is presented. The performance of the two components (scanner and dosimeter) was investigated separately prior to full system test. The optical CT scanner has a spatial resolution of < or = 1 mm, geometric accuracy within 1 mm, and high reconstruction linearity (with a R2 value of 0.9979 and a standard error of estimation of approximately 1%) relative to independent measurement. The overall performance of the PRESAGE/OCTOPUS system was evaluated with respect to a simple known 3D dose distribution, by comparison with GAFCHROMIC EBT film and the calculated dose from a commissioned planning system. The "measured" dose distribution in a cylindrical PRESAGE dosimeter (16 cm diameter and 11 cm height) was determined by optical-CT, using a filtered backprojection reconstruction algorithm. A three-way Gamma map comparison (4% dose difference and 4 mm distance to agreement), between the PRESAGE, EBT and calculated dose distributions, showed full agreement in measurable region of PRESAGE dosimeter (approximately 90% of radius). The EBT and PRESAGE distributions agreed

  4. A practical three-dimensional dosimetry system for radiation therapy

    PubMed Central

    Guo, Pengyi; Adamovics, John; Oldham, Mark

    2006-01-01

    There is a pressing need for a practical three-dimensional (3D) dosimetry system, convenient for clinical use, and with the accuracy and resolution to enable comprehensive verification of the complex dose distributions typical of modern radiation therapy. Here we introduce a dosimetry system that can achieve this challenge, consisting of a radiochromic dosimeter (PRESAGE™) and a commercial optical computed tomography (CT) scanning system (OCTOPUS™). PRESAGE™ is a transparent material with compelling properties for dosimetry, including insensitivity of the dose response to atmospheric exposure, a solid texture negating the need for an external container (reducing edge effects), and amenability to accurate optical CT scanning due to radiochromic optical contrast as opposed to light-scattering contrast. An evaluation of the performance and viability of the PRESAGE™/OCTOPUS, combination for routine clinical 3D dosimetry is presented. The performance of the two components (scanner and dosimeter) was investigated separately prior to full system test. The optical CT scanner has a spatial resolution of ≤1 mm, geometric accuracy within 1 mm, and high reconstruction linearity (with a R2 value of 0.9979 and a standard error of estimation of ~1%) relative to independent measurement. The overall performance of the PRESAGE™/OCTOPUS system was evaluated with respect to a simple known 3D dose distribution, by comparison with GAFCHROMIC® EBT film and the calculated dose from a commissioned planning system. The “measured” dose distribution in a cylindrical PRESAGE™ dosimeter (16 cm diameter and 11 cm height) was determined by optical-CT, using a filtered backprojection reconstruction algorithm. A three-way Gamma map comparison (4% dose difference and 4 mm distance to agreement), between the PRESAGE™, EBT and calculated dose distributions, showed full agreement in measurable region of PRESAGE™ dosimeter (~90% of radius). The EBT and PRESAGE™ distributions

  5. High-dose accelerated hypofractionated three-dimensional conformal radiotherapy (at 3 Gy/fraction) with concurrent vinorelbine and carboplatin chemotherapy in locally advanced non-small-cell lung cancer: a feasibility study

    PubMed Central

    2013-01-01

    Background Increasing the radiotherapy dose can result in improved local control for non-small-cell lung cancer (NSCLC) and can thereby improve survival. Accelerated hypofractionated radiotherapy can expose tumors to a high dose of radiation in a short period of time, but the optimal treatment regimen remains unclear. The purpose of this study was to evaluate the feasibility of utilizing high-dose accelerated hypofractionated three-dimensional conformal radiotherapy (at 3 Gy/fraction) with concurrent vinorelbine (NVB) and carboplatin (CBP) chemotherapy for the treatment of local advanced NSCLC. Methods Untreated patients with unresectable stage IIIA/IIIB NSCLC or patients with a recurrence of NSCLC received accelerated hypofractionated three-dimensional conformal radiotherapy. The total dose was greater than or equal to 60 Gy. The accelerated hypofractionated radiotherapy was conducted once daily at 3 Gy/fraction with 5 fractions per week, and the radiotherapy was completed in 5 weeks. In addition to radiotherapy, the patients also received at least 1 cycle of a concurrent two-drug chemotherapy regimen of NVB and CBP. Results A total of 26 patients (19 previously untreated cases and 7 cases of recurrent disease) received 60Gy-75Gy radiotherapy with concurrent chemotherapy. All of the patients underwent evaluations for toxicity and preliminary therapeutic efficacy. There were no treatment-related deaths within the entire patient group. The major acute adverse reactions were radiation esophagitis (88.5%) and radiation pneumonitis (42.3%). The percentages of grade III acute radiation esophagitis and grade III radiation pneumonitis were 15.4% and 7.7%, respectively. Hematological toxicities were common and did not significantly affect the implementation of chemoradiotherapy after supportive treatment. Two patients received high dose of 75 Gy had grade III late esophageal toxicity, and none had grade IV and above. Grade III and above late lung toxicity did not occur

  6. High-dose accelerated hypofractionated three-dimensional conformal radiotherapy (at 3 Gy/fraction) with concurrent vinorelbine and carboplatin chemotherapy in locally advanced non-small-cell lung cancer: a feasibility study.

    PubMed

    Liu, Yue-E; Lin, Qiang; Meng, Fan-Jie; Chen, Xue-Ji; Ren, Xiao-Cang; Cao, Bin; Wang, Na; Zong, Jie; Peng, Yu; Ku, Ya-Jun; Chen, Yan

    2013-08-11

    Increasing the radiotherapy dose can result in improved local control for non-small-cell lung cancer (NSCLC) and can thereby improve survival. Accelerated hypofractionated radiotherapy can expose tumors to a high dose of radiation in a short period of time, but the optimal treatment regimen remains unclear. The purpose of this study was to evaluate the feasibility of utilizing high-dose accelerated hypofractionated three-dimensional conformal radiotherapy (at 3 Gy/fraction) with concurrent vinorelbine (NVB) and carboplatin (CBP) chemotherapy for the treatment of local advanced NSCLC. Untreated patients with unresectable stage IIIA/IIIB NSCLC or patients with a recurrence of NSCLC received accelerated hypofractionated three-dimensional conformal radiotherapy. The total dose was greater than or equal to 60 Gy. The accelerated hypofractionated radiotherapy was conducted once daily at 3 Gy/fraction with 5 fractions per week, and the radiotherapy was completed in 5 weeks. In addition to radiotherapy, the patients also received at least 1 cycle of a concurrent two-drug chemotherapy regimen of NVB and CBP. A total of 26 patients (19 previously untreated cases and 7 cases of recurrent disease) received 60Gy-75Gy radiotherapy with concurrent chemotherapy. All of the patients underwent evaluations for toxicity and preliminary therapeutic efficacy. There were no treatment-related deaths within the entire patient group. The major acute adverse reactions were radiation esophagitis (88.5%) and radiation pneumonitis (42.3%). The percentages of grade III acute radiation esophagitis and grade III radiation pneumonitis were 15.4% and 7.7%, respectively. Hematological toxicities were common and did not significantly affect the implementation of chemoradiotherapy after supportive treatment. Two patients received high dose of 75 Gy had grade III late esophageal toxicity, and none had grade IV and above. Grade III and above late lung toxicity did not occur. High-dose accelerated

  7. CT based three dimensional dose-volume evaluations for high-dose rate intracavitary brachytherapy for cervical cancer

    PubMed Central

    2014-01-01

    Background In this study, high risk clinical target volumes (HR-CTVs) according to GEC-ESTRO guideline were contoured retrospectively based on CT images taken at the time of high-dose rate intracavitary brachytherapy (HDR-ICBT) and correlation between clinical outcome and dose of HR-CTV were analyzed. Methods Our study population consists of 51 patients with cervical cancer (Stages IB-IVA) treated with 50 Gy external beam radiotherapy (EBRT) using central shield combined with 2–5 times of 6 Gy HDR-ICBT with or without weekly cisplatin. Dose calculation was based on Manchester system and prescribed dose of 6 Gy were delivered for point A. CT images taken at the time of each HDR-ICBT were reviewed and HR-CTVs were contoured. Doses were converted to the equivalent dose in 2 Gy (EQD2) by applying the linear quadratic model (α/β = 10 Gy). Results Three-year overall survival, Progression-free survival, and local control rate was 82.4%, 85.3% and 91.7%, respectively. Median cumulative dose of HR-CTV D90 was 65.0 Gy (52.7-101.7 Gy). Median length from tandem to the most lateral edge of HR-CTV at the first ICBT was 29.2 mm (range, 18.0-51.9 mm). On univariate analysis, both LCR and PFS was significantly favorable in those patients D90 for HR-CTV was 60 Gy or greater (p = 0.001 and 0.03, respectively). PFS was significantly favorable in those patients maximum length from tandem to edge of HR-CTV at first ICBT was shorter than 3.5 cm (p = 0.042). Conclusion Volume-dose showed a relationship to the clinical outcome in CT based brachytherapy for cervical carcinoma. PMID:24938757

  8. Three-dimensional, position-sensitive radiation detection

    DOEpatents

    He, Zhong; Zhang, Feng

    2010-04-06

    Disclosed herein is a method of determining a characteristic of radiation detected by a radiation detector via a multiple-pixel event having a plurality of radiation interactions. The method includes determining a cathode-to-anode signal ratio for a selected interaction of the plurality of radiation interactions based on electron drift time data for the selected interaction, and determining the radiation characteristic for the multiple-pixel event based on both the cathode-to-anode signal ratio and the electron drift time data. In some embodiments, the method further includes determining a correction factor for the radiation characteristic based on an interaction depth of the plurality of radiation interactions, a lateral distance between the selected interaction and a further interaction of the plurality of radiation interactions, and the lateral positioning of the plurality of radiation interactions.

  9. Flux canceling in three-dimensional radiative magnetohydrodynamic simulations

    NASA Astrophysics Data System (ADS)

    Thaler, Irina; Spruit, H. C.

    2017-05-01

    We aim to study the processes involved in the disappearance of magnetic flux between regions of opposite polarity on the solar surface using realistic three-dimensional (3D) magnetohydrodynamic (MHD) simulations. "Retraction" below the surface driven by magnetic forces is found to be a very effective mechanism of flux canceling of opposite polarities. The speed at which flux disappears increases strongly with initial mean flux density. In agreement with existing inferences from observations we suggest that this is a key process of flux disappearance within active complexes. Intrinsic kG strength concentrations connect the surface to deeper layers by magnetic forces, and therefore the influence of deeper layers on the flux canceling process is studied. We do this by comparing simulations extending to different depths. For average flux densities of 50 G, and on length scales on the order of 3 Mm in the horizontal and 10 Mm in depth, deeper layers appear to have only a mild influence on the effective rate of diffusion.

  10. Preliminary results of a three-dimensional radiative transfer model

    SciTech Connect

    O`Hirok, W.

    1995-09-01

    Clouds act as the primary modulator of the Earth`s radiation at the top of the atmosphere, within the atmospheric column, and at the Earth`s surface. They interact with both shortwave and longwave radiation, but it is primarily in the case of shortwave where most of the uncertainty lies because of the difficulties in treating scattered solar radiation. To understand cloud-radiative interactions, radiative transfer models portray clouds as plane-parallel homogeneous entities to ease the computational physics. Unfortunately, clouds are far from being homogeneous, and large differences between measurement and theory point to a stronger need to understand and model cloud macrophysical properties. In an attempt to better comprehend the role of cloud morphology on the 3-dimensional radiation field, a Monte Carlo model has been developed. This model can simulate broadband shortwave radiation fluxes while incorporating all of the major atmospheric constituents. The model is used to investigate the cloud absorption anomaly where cloud absorption measurements exceed theoretical estimates and to examine the efficacy of ERBE measurements and cloud field experiments. 3 figs.

  11. Formation of globular clusters induced by external ultraviolet radiation - II. Three-dimensional radiation hydrodynamics simulations

    NASA Astrophysics Data System (ADS)

    Abe, Makito; Umemura, Masayuki; Hasegawa, Kenji

    2016-12-01

    We explore the possibility of the formation of globular clusters (GCs) under ultraviolet (UV) background radiation. One-dimensional spherical symmetric radiation hydrodynamics (RHD) simulations by Hasegawa et al. have demonstrated that the collapse of low-mass (106-7 M⊙) gas clouds exposed to intense UV radiation can lead to the formation of compact star clusters like GCs if gas clouds contract with supersonic infall velocities. However, three-dimensional effects, such as the anisotropy of background radiation and the inhomogeneity in gas clouds, have not been studied so far. In this paper, we perform three-dimensional RHD simulations in a semicosmological context, and reconsider the formation of compact star clusters in strong UV radiation fields. As a result, we find that although anisotropic radiation fields bring an elongated shadow of neutral gas, almost spherical compact star clusters can be procreated from a `supersonic infall' cloud, since photodissociating radiation suppresses the formation of hydrogen molecules in the shadowed regions and the regions are compressed by UV heated ambient gas. The properties of resultant star clusters match those of GCs. On the other hand, in weak UV radiation fields, dark-matter-dominated star clusters with low stellar density form due to the self-shielding effect as well as the positive feedback by ionizing photons. Thus, we conclude that the `supersonic infall' under a strong UV background is a potential mechanism to form GCs.

  12. Understanding Accretion Disks through Three Dimensional Radiation MHD Simulations

    NASA Astrophysics Data System (ADS)

    Jiang, Yan-Fei

    I study the structures and thermal properties of black hole accretion disks in the radiation pressure dominated regime. Angular momentum transfer in the disk is provided by the turbulence generated by the magneto-rotational instability (MRI), which is calculated self-consistently with a recently developed 3D radiation magneto-hydrodynamics (MHD) code based on Athena. This code, developed by my collaborators and myself, couples both the radiation momentum and energy source terms with the ideal MHD equations by modifying the standard Godunov method to handle the stiff radiation source terms. We solve the two momentum equations of the radiation transfer equations with a variable Eddington tensor (VET), which is calculated with a time independent short characteristic module. This code is well tested and accurate in both optically thin and optically thick regimes. It is also accurate for both radiation pressure and gas pressure dominated flows. With this code, I find that when photon viscosity becomes significant, the ratio between Maxwell stress and Reynolds stress from the MRI turbulence can increase significantly with radiation pressure. The thermal instability of the radiation pressure dominated disk is then studied with vertically stratified shearing box simulations. Unlike the previous results claiming that the radiation pressure dominated disk with MRI turbulence can reach a steady state without showing any unstable behavior, I find that the radiation pressure dominated disks always either collapse or expand until we have to stop the simulations. During the thermal runaway, the heating and cooling rates from the simulations are consistent with the general criterion of thermal instability. However, details of the thermal runaway are different from the predictions of the standard alpha disk model, as many assumptions in that model are not satisfied in the simulations. We also identify the key reasons why previous simulations do not find the instability. The thermal

  13. Three-dimensional architecture for solid state radiation detectors

    DOEpatents

    Parker, S.

    1999-03-30

    A radiation-damage resistant radiation detector is formed on a substrate formed of a material doped with a first conductivity type dopant. The detector includes at least one first electrode formed of first conductivity type dopant, and at least one second electrode that is spaced-apart from the first electrode and formed of a second conductivity type dopant. Each first and second electrode penetrates into the substrate from a substrate surface, and one or more electrodes may penetrate entirely through the substrate, that is traversing from one surface to the other surface. Particulate and/or electromagnetic radiation penetrating at least a surface of the substrate releases electrons and holes in substrate regions. Because the electrodes may be formed entirely through the substrate thickness, the released charges will be a relatively small distance from at least a portion of such an electrode, e.g., a distance less than the substrate thickness. The electrons and/or holes traverse the small distance and are collected by said electrodes, thus promoting rapid detection of the radiation. By providing one or more electrodes with a dopant profile radially graded in a direction parallel to a substrate surface, an electric field results that promotes rapid collection of released electrons and said holes. Monolithic combinations of such detectors may be fabricated including CMOS electronics to process radiation signals. 45 figs.

  14. Three-dimensional architecture for solid state radiation detectors

    DOEpatents

    Parker, Sherwood

    1999-01-01

    A radiation-damage resistant radiation detector is formed on a substrate formed of a material doped with a first conductivity type dopant. The detector includes at least one first electrode formed of first conductivity type dopant, and at least one second electrode that is spaced-apart from the first electrode and formed of a second conductivity type dopant. Each first and second electrode penetrates into the substrate from a substrate surface, and one or more electrodes may penetrate entirely through the substrate, that is traversing from one surface to the other surface. Particulate and/or electromagnetic radiation penetrating at least a surface of the substrate releases electrons and holes in substrate regions. Because the electrodes may be formed entirely through the substrate thickness, the released charges will be a relatively small distance from at least a portion of such an electrode, e.g., a distance less than the substrate thickness. The electrons and/or holes traverse the small distance and are collected by said electrodes, thus promoting rapid detection of the radiation. By providing one or more electrodes with a dopant profile radially graded in a direction parallel to a substrate surface, an electric field results that promotes rapid collection of released electrons and said holes. Monolithic combinations of such detectors may be fabricated including CMOS electronics to process radiation signals.

  15. Three Dimensional Radiative Transfer In Tropical Deep Convective Clouds.

    NASA Astrophysics Data System (ADS)

    di Giuseppe, F.

    In this study the focus is on the interaction between short-wave radiation with a field of tropical deep convective events generated using a 3D cloud resolving model (CRM) to assess the significance of 3D radiative transport (3DRT). It is not currently un- derstood what magnitude of error is involved when a two stream approximation is used to describe the radiative transfer through such a cloud field. It seems likely that deep convective clouds could be the most complex to represent, and that the error in neglecting horizontal transport could be relevant in these cases. The field here con- sidered has an extention of roughly 90x90 km, approximately equivalent to the grid box dimension of many global models. The 3DRT results are compared both with the calculations obtained by an Independent Pixel Approximation (IPA) approch and by the Plane Parallel radiative scheme (PP) implemented in ECMWF's Forecast model. The differences between the three calculations are used to assess both problems in current GCM's representation of radiative heating and inaccuracies in the dynamical response of CRM simulations due to the Independent Column Approximation (ICA). The understanding of the mechanisms involved in the main 3DRT/1D differences is the starting point for the future attempt to develop a parameterization procedure.

  16. Three-Dimensional Analysis of Optical Transition Radiation

    DTIC Science & Technology

    1988-12-01

    may be observed from the front face of the foil and is called backward transition radiation siliCe it is reflected back fLou- the foil. Transition...reflection coefficients. The Lorentz factor , aPI the velocity / are defined E -1+ KE , (2.3) and ~= - (2.4) The parallel and perpendicular reflection...Re[(-y-N2Z/ax)W(Z)+ax (2/ )l/2] , (2.8) where Z is defined as (I +i0)/a, ax as the rms beam angle of divergence projected into the observation plane

  17. Three-dimensional radiative transfer on a massively parallel computer

    NASA Technical Reports Server (NTRS)

    Vath, H. M.

    1994-01-01

    We perform 3D radiative transfer calculations in non-local thermodynamic equilibrium (NLTE) in the simple two-level atom approximation on the Mas-Par MP-1, which contains 8192 processors and is a single instruction multiple data (SIMD) machine, an example of the new generation of massively parallel computers. On such a machine, all processors execute the same command at a given time, but on different data. To make radiative transfer calculations efficient, we must re-consider the numerical methods and storage of data. To solve the transfer equation, we adopt the short characteristic method and examine different acceleration methods to obtain the source function. We use the ALI method and test local and non-local operators. Furthermore, we compare the Ng and the orthomin methods of acceleration. We also investigate the use of multi-grid methods to get fast solutions for the NLTE case. In order to test these numerical methods, we apply them to two problems with and without periodic boundary conditions.

  18. Delay-Line Three-Dimensional Position Sensitive Radiation Detection

    NASA Astrophysics Data System (ADS)

    Jeong, Manhee

    High-resistivity silicon(Si) in large volumes and with good charge carrier transport properties has been produced and achieved success as a radiation detector material over the past few years due to its relatively low cost as well as the availability of well-established processing technologies. One application of that technology is in the fabrication of various position-sensing topologies from which the incident radiation's direction can be determined. We have succeeded in developing the modeling tools for investigating different position-sensing schemes and used those tools to examine both amplitude-based and time-based methods, an assessment that indicates that fine position-sensing can be achieved with simpler readout designs than are conventionally deployed. This realization can make ubiquitous and inexpensive deployment of special nuclear materials (SNM) detecting technology becomes more feasible because if one can deploy position-sensitive semiconductor detectors with only one or two contacts per side. For this purpose, we have described the delay-line radiation detector and its optimized fabrication. The semiconductor physics were simulated, the results from which guided the fabrication of the guard ring structure and the detector electrode, both of which included metal-field-plates. The measured improvement in the leakage current was confirmed with the fabricated devices, and the structures successfully suppressed soft-breakdown. We also demonstrated that fabricating an asymmetric strip-line structure successfully minimizing the pulse shaping and increases the distance through which one can propagate the information of the deposited charge distribution. With fabricated delay-line detectors we can acquire alpha spectra (Am-241) and gamma spectra (Ba-133, Co-57 and Cd-109). The delay-line detectors can therefore be used to extract the charge information from both ion and gamma-ray interactions. Furthermore, standard charge-sensitive circuits yield high SNR

  19. Three-dimensional imaging of optically opaque materials using nonionizing terahertz radiation.

    PubMed

    Wallace, Vincent P; Macpherson, Emma; Zeitler, J Axel; Reid, Caroline

    2008-12-01

    Terahertz electromagnetic radiation has already been shown to have a wide number of uses. We consider specific applications of terahertz time-domain imaging that are inherently three-dimensional. This paper highlights the ability of terahertz radiation to reveal subsurface information as we exploit the fact that the radiation can penetrate optically opaque materials such as clothing, cardboard, plastics, and to some extent biological tissue. Using interactive science publishing tools, we concentrate on full three-dimensional terahertz data from three specific areas of application, namely, security, pharmaceutical, and biomedical.

  20. Implementation of three dimensional conformal radiation therapy: prospects, opportunities, and challenges.

    PubMed

    Vijayakumar, S; Chen, G T

    1995-12-01

    (s). Such definitions should make implementation of 3DCRT more complex, yet will make high-dose delivery a possibility. There are many sites in which single and multiinstitutional studies are ongoing that include prostate, lung, head and neck, and brain. In other areas, cooperative group trials are required because of the inability of single institutions to accrue enough patients to answer clinically relevant questions with statistical validity. Although implementation of 3DCRT will require multiple steps, these multiple steps can be brought into clinical practice gradually and one does not have to wait until all steps required for implementation of 3DCRT are available. In this respect, "3DCRT" should be used in a very broad sense, from beam's eye view blocking, use of multibeam dose distribution, use of dose-volume histograms in choosing alternative plans, noncoplanar beam arrangements, intensity modulation, inverse planning, to totally automated implementation of 3DCRT. To transfer the 3DCRT capabilities to the community from the University Centers, there is a necessity to develop quality assurance programs. RTOG and the Three-Dimensional Oncology Group are spearheading these efforts. Three-dimensional conformal radiation therapy has potential not only to improve local control and decrease toxicity, but also to improve the cost benefit ratio in the use of radiotherapy as well as in improving quality of life in patients with cancer. Achieving many potential benefits of 3DCRT (improvement in local control, decreasing toxicity, organs-function preservation, improvement in cost effectiveness) will require further physics-related and clinical research in carefully conceived and successfully completed future clinical trials.

  1. A quantitative three-dimensional dose attenuation analysis around Fletcher-Suit-Delclos due to stainless steel tube for high-dose-rate brachytherapy by Monte Carlo calculations.

    PubMed

    Parsai, E Ishmael; Zhang, Zhengdong; Feldmeier, John J

    2009-01-01

    The commercially available brachytherapy treatment-planning systems today, usually neglects the attenuation effect from stainless steel (SS) tube when Fletcher-Suit-Delclos (FSD) is used in treatment of cervical and endometrial cancers. This could lead to potential inaccuracies in computing dwell times and dose distribution. A more accurate analysis quantifying the level of attenuation for high-dose-rate (HDR) iridium 192 radionuclide ((192)Ir) source is presented through Monte Carlo simulation verified by measurement. In this investigation a general Monte Carlo N-Particles (MCNP) transport code was used to construct a typical geometry of FSD through simulation and compare the doses delivered to point A in Manchester System with and without the SS tubing. A quantitative assessment of inaccuracies in delivered dose vs. the computed dose is presented. In addition, this investigation expanded to examine the attenuation-corrected radial and anisotropy dose functions in a form parallel to the updated AAPM Task Group No. 43 Report (AAPM TG-43) formalism. This will delineate quantitatively the inaccuracies in dose distributions in three-dimensional space. The changes in dose deposition and distribution caused by increased attenuation coefficient resulted from presence of SS are quantified using MCNP Monte Carlo simulations in coupled photon/electron transport. The source geometry was that of the Vari Source wire model VS2000. The FSD was that of the Varian medical system. In this model, the bending angles of tandem and colpostats are 15 degrees and 120 degrees , respectively. We assigned 10 dwell positions to the tandem and 4 dwell positions to right and left colpostats or ovoids to represent a typical treatment case. Typical dose delivered to point A was determined according to Manchester dosimetry system. Based on our computations, the reduction of dose to point A was shown to be at least 3%. So this effect presented by SS-FSD systems on patient dose is of concern.

  2. Dosimetric comparison between three dimensional treatment planning system, Monte Carlo simulation and gel dosimetry in nasopharynx phantom for high dose rate brachytherapy.

    PubMed

    Fazli, Zeynab; Sadeghi, Mahdi; Zahmatkesh, M H; Mahdavi, Seied Rabei; Tenreiro, Claudio

    2013-01-01

    For the treatment of nasopharnx carcinoma (NPC) using brachytherapy methods and high-energy photon sources are common techniques. In the common three dimensional (3D) treatments planning, all of the computed tomography images are assumed homogeneous. This study presents the results of Monte Carlo calculations for non-homogeneous nasopharynx phantom, MAGICA normoxic gel dosimetry and 3D treatment planning system (TPS). The head phantom was designed with Plexiglas cylinder, head bone, and nasopharynx brachytherapy silicon applicator. For the simulations, version 5 of the Monte Carlo N-particle transport code (MCNP5) was used. 3D treatment planning was performed in Flexiplan software. A normoxic radiosensitive polymer gel was fabricated under normal atmospheric conditions and poured into test tubes (for calibration curve) and the head phantom. In addition, the head phantom was irradiated with Flexitron afterloader brachytherapy machine with (192)Ir source. To obtain calibration curves, 11 dosimeters were irradiated with dose range of 0-2000 cGy. Evaluations of dosimeters were performed on 1.5T scanner. Two-dimensional iso-dose in coronal plan at distances of z = +0.3, -0.3 cm was calculated. There was a good accordance between 3D TPS and MCNP5 simulation and differences in various distances were between 2.4% and 6.1%. There was a predictable accordance between MAGICA gel dosimetry and MCNP5 simulation and differences in various distances were between 5.7% and 7.4%. Moreover, there was an acceptable accordance between MAGICA gel dosimetry and MCNP5 data and differences in various distances were between 5.2% and 9.4%. The sources of differences in this comparison are divided to calculations variation and practical errors that was added in experimental dosimetry. The result of quality assurance of nasopharynx high dose rate brachytherapy is consistent with international standards.

  3. Three-dimensional visualization of shear wave propagation generated by dual acoustic radiation pressure

    NASA Astrophysics Data System (ADS)

    Mochizuki, Yuta; Taki, Hirofumi; Kanai, Hiroshi

    2016-07-01

    An elastic property of biological soft tissue is an important indicator of the tissue status. Therefore, quantitative and noninvasive methods for elasticity evaluation have been proposed. Our group previously proposed a method using acoustic radiation pressure irradiated from two directions for elastic property evaluation, in which by measuring the propagation velocity of the shear wave generated by the acoustic radiation pressure inside the object, the elastic properties of the object were successfully evaluated. In the present study, we visualized the propagation of the shear wave in a three-dimensional space by the synchronization of signals received at various probe positions. The proposed method succeeded in visualizing the shear wave propagation clearly in the three-dimensional space of 35 × 41 × 4 mm3. These results show the high potential of the proposed method to estimate the elastic properties of the object in the three-dimensional space.

  4. Three-dimensional radiation dosimetry for gamma knife using a gel dosimeter

    NASA Astrophysics Data System (ADS)

    Hussain, Kazi Muazzam

    The use of three-dimensional radiation dosimetry has been limited. With the use of water phantoms and ionization chambers, it has been possible to determine three dimensional dose distributions on a gross scale for cobalt 60 and linear accelerator sources. This method has been somewhat useful for traditional radiotherapy. There is, however, a need for more precise dosimetry, particularly with stereotactic radiosurgery. Most gamma knife facilities use either thermoluminescant dosimetry or film, neither of which provides three dimensional dose distributions. To overcome this limitation, we have developed a gel dosimetry system that relies on the production of a ferric ion-xylenol orange colored complex. This work demonstrates the use of laser light and a detector to quantify radiation-induced colorimetric changes in absorbance for the gel dosimeter. The absorbance has been reconstructed by the back projection technique to demonstrate the applicability of the gel dosimeter to gamma knife 3D-dose distributions.

  5. High-dose radiation sensor with wireless optical detection

    NASA Astrophysics Data System (ADS)

    Knapkiewicz, Paweł; Augustyniak, Izabela; Sareło, Katarzyna; Gorecka-Drzazga, Anna; Dziuban, Jan

    2017-05-01

    We present a miniature silicon-glass MEMS sensor for measurement of high doses of ionizing radiation (above 10 kGy) using a novel wireless optical detection method. The radiation sensor is a miniaturized version of the so-called hydrogen dosimeter. An amount of high-density polyethylene, located inside the MEMS sensor, degrades under ionizing radiation, releasing gaseous hydrogen. The increasing pressure deflects the thin silicon membrane. The sensor’s destructive and proportional modes of work are also proposed. In the destructive mode, sensors provide in situ information on excessive and discrete levels of radiation. The optical detection method is based on an optical head consisting of a moving membrane and a silicon screen with a matrix of micro-holes. Laser light is reflected from the membrane and scattered when the membrane is deflected, in the process illuminating the holes on the silicon screen. The number of illuminated holes is a function of the degree of membrane deflection; the transformation of the holes to the deflection allows for the calculation of pressure and eventually the dose of ionizing radiation.

  6. Equivalent Biochemical Control and Improved Prostate-Specific Antigen Nadir After Permanent Prostate Seed Implant Brachytherapy Versus High-Dose Three-Dimensional Conformal Radiotherapy and High-Dose Conformal Proton Beam Radiotherapy Boost

    SciTech Connect

    Jabbari, Siavash; Weinberg, Vivian K.; Shinohara, Katsuto; Speight, Joycelyn L.; Gottschalk, Alexander R.; Hsu, I.-C.; Pickett, Barby; McLaughlin, Patrick W.; Sandler, Howard M.; Roach, Mack

    2010-01-15

    Purpose: Permanent prostate implant brachytherapy (PPI), three-dimensional conformal radiotherapy (3D-CRT), and conformal proton beam radiotherapy (CPBRT) are used in the treatment of localized prostate cancer, although no head-to-head trials have compared these modalities. We studied the biochemical control (biochemical no evidence of disease [bNED]) and prostate-specific antigen (PSA) nadir achieved with contemporary PPI, and evaluated it against 3D-CRT and CPBRT. Patients and Methods: A total of 249 patients were treated with PPI at the University of California, San Francisco, and the outcomes were compared with those from a 3D-CRT cohort and the published results of a high-dose CPBRT boost (CPBRTB) trial. For each comparison, subsets of the PPI cohort were selected with patient and disease criteria similar to those of the reference group. Results: With a median follow-up of 5.3 years, the bNED rate at 5 and 7 years achieved with PPI was 92% and 86%, respectively, using the American Society for Therapeutic Radiology and Oncology (ASTRO) definition, and 93% using the PSA nadir plus 2 ng/mL definition. Using the ASTRO definition, a 5-year bNED rate of 78% was achieved for the 3D-CRT patients compared with 94% for a comparable PPI subset and 93% vs. 92%, respectively, using the PSA nadir plus 2 ng/mL definition. The median PSA nadir for patients treated with PPI and 3D-CRT was 0.10 and 0.40 ng/mL, respectively (p < .0001). For the CPBRT comparison, the 5-year bNED rate after a CPBRTB was 91% using the ASTRO definition vs. 93% for a similar group of PPI patients. A greater proportion of PPI patients achieved a lower PSA nadir compared with those achieved in the CPBRTB trial (PSA nadir <=0.5 ng/mL, 91% vs. 59%, respectively). Conclusion: We have demonstrated excellent outcomes in low- to intermediate-risk patients treated with PPI, suggesting at least equivalent 5-year bNED rates and a greater proportion of men achieving lower PSA nadirs compared with 3D-CRT or

  7. Three-dimensional simulation of super-radiant Smith-Purcell radiation

    SciTech Connect

    Li, D.; Imasaki, K.; Yang, Z.; Park, Gun-Sik

    2006-05-15

    A simulation of coherent and super-radiant Smith-Purcell radiation is performed in the gigahertz regime using a three-dimensional particle-in-cell code. The simulation model supposes a rectangular grating to be driven by a single electron bunch and a train of periodic bunches, respectively. The true Smith-Purcell radiation is distinguished from the evanescent wave, which has an angle independent frequency lower than the minimum allowed Smith-Purcell frequency. We also find that the super-radiant radiations excited by periodic bunches are emitted at higher harmonics of the bunching frequency and at the corresponding Smith-Purcell angles.

  8. Recent Developments in Three Dimensional Radiation Transport Using the Green's Function Technique

    NASA Technical Reports Server (NTRS)

    Rockell, Candice; Tweed, John; Blattnig, Steve R.; Mertens, Christopher J.

    2010-01-01

    In the future, astronauts will be sent into space for longer durations of time compared to previous missions. The increased risk of exposure to dangerous radiation, such as Galactic Cosmic Rays and Solar Particle Events, is of great concern. Consequently, steps must be taken to ensure astronaut safety by providing adequate shielding. In order to better determine and verify shielding requirements, an accurate and efficient radiation transport code based on a fully three dimensional radiation transport model using the Green's function technique is being developed

  9. Hawking radiation of spin-1 particles from a three-dimensional rotating hairy black hole

    SciTech Connect

    Sakalli, I.; Ovgun, A.

    2015-09-15

    We study the Hawking radiation of spin-1 particles (so-called vector particles) from a three-dimensional rotating black hole with scalar hair using a Hamilton–Jacobi ansatz. Using the Proca equation in the WKB approximation, we obtain the tunneling spectrum of vector particles. We recover the standard Hawking temperature corresponding to the emission of these particles from a rotating black hole with scalar hair.

  10. Using Synchrotron Radiation Microtomography to Investigate Multi-scale Three-dimensional Microelectronic Packages

    SciTech Connect

    Carlton, Holly D.; Elmer, John W.; Li, Yan; Pacheco, Mario; Goyal, Deepak; Parkinson, Dilworth Y.; MacDowell, Alastair A.

    2016-04-13

    For this study synchrotron radiation micro-­tomography, a non-destructive three-dimensional imaging technique, is employed to investigate an entire microelectronic package with a cross-sectional area of 16 x 16 mm. Due to the synchrotron’s high flux and brightness the sample was imaged in just 3 minutes with an 8.7 μm spatial resolution.

  11. Using Synchrotron Radiation Microtomography to Investigate Multi-scale Three-dimensional Microelectronic Packages

    SciTech Connect

    Carlton, Holly D.; Elmer, John W.; Li, Yan; Pacheco, Mario; Goyal, Deepak; Parkinson, Dilworth Y.; MacDowell, Alastair A.

    2016-04-13

    For this study synchrotron radiation micro-­tomography, a non-destructive three-dimensional imaging technique, is employed to investigate an entire microelectronic package with a cross-sectional area of 16 x 16 mm. Due to the synchrotron’s high flux and brightness the sample was imaged in just 3 minutes with an 8.7 μm spatial resolution.

  12. Three-dimensional surface grid generation for calculation of thermal radiation shape factors

    NASA Technical Reports Server (NTRS)

    Aly, Hany M.

    1992-01-01

    A technique is described to generate three dimensional surface grids suitable for calculating shape factors for thermal radiative heat transfer. The surface under consideration is approximated by finite triangular elements generated in a special manner. The grid is generated by dividing the surface into a two dimensional array of nodes. Each node is defined by its coordinates. Each set of four adjacent nodes is used to construct two triangular elements. Each triangular element is characterized by the vector representation of its vertices. Vector algebra is used to calculate all desired geometric properties of grid elements. The properties are used to determine the shape factor between the element and an area element in space. The grid generation can be graphically displayed using any software with three dimensional features. DISSPLA was used to view the grids.

  13. Modelling canopy scale solar induced chlorophyll fluorescence simulated by the three dimensional radiative transfer model

    NASA Astrophysics Data System (ADS)

    Kobayashi, H.; Nagai, S.; Inoue, T.; Yang, W.; Ichii, K.

    2014-12-01

    Recent studies show that the vegetation canopy scale sun-induced chlorophyll fluorescence (SIF) can be observed from satellite. To understand how the canopy scale bidirectional fluorescence observations are related to three-dimensional fluorescence distribution within a plant canopy, it is necessary to evaluate canopy scale fluorescence emission using a detailed plant canopy radiative transfer model. In this study, we developed a three-dimensional plant canopy radiative transfer model that can simulate the bidirectional chlorophyll fluorescence radiance and show several preliminary results of fluorescence distribution at the tree level. To simulate the three dimensional variations in chlorophyll fluorescence from trees, we measured tree structures using a terrestrial LiDAR instrument. The measurements were conducted in Yokohama, Japan (35°22'49" N 139°37'29" E). Three Japanese cherry trees (Cerasus Speciosa) were chosen for our study (Figure 1). Leaf-level sun-induced chlorophyll fluorescence (SIF) is also necessary as an input of radiative transfer model. To measure the leaf-level SIF, we used high spectral resolution spectroradiometer (HR 4000, Ocean Optics Inc. USA). The spectral resolution of this instrument is 0.05 nm (full width half maximum). The spectral range measured was 720 to 780 nm. From the spectral radiance measurements, we estimated SIF using the three band Fraunhofer Line Depth (3FLD) method. The effect of solar and view zenith angles, multiple scattering depends on many factors such as back ground reflectance, leaf reflectance transmittance and landscape structures. To understand how the SIF from both sparse and dense forest stands vary with sun and view angles and optical variables, it is necessary to conduct further sensitivity analysis. Radiative transfer simulation will help understand SIF emission at variety of forest canopy cases.

  14. On the Development of a Deterministic Three-Dimensional Radiation Transport Code

    NASA Technical Reports Server (NTRS)

    Rockell, Candice; Tweed, John

    2011-01-01

    Since astronauts on future deep space missions will be exposed to dangerous radiations, there is a need to accurately model the transport of radiation through shielding materials and to estimate the received radiation dose. In response to this need a three dimensional deterministic code for space radiation transport is now under development. The new code GRNTRN is based on a Green's function solution of the Boltzmann transport equation that is constructed in the form of a Neumann series. Analytical approximations will be obtained for the first three terms of the Neumann series and the remainder will be estimated by a non-perturbative technique . This work discusses progress made to date and exhibits some computations based on the first two Neumann series terms.

  15. Extending generalized Kubelka-Munk to three-dimensional radiative transfer.

    PubMed

    Sandoval, Christopher; Kim, Arnold D

    2015-08-10

    The generalized Kubelka-Munk (gKM) approximation is a linear transformation of the double spherical harmonics of order one (DP1) approximation of the radiative transfer equation. Here, we extend the gKM approximation to study problems in three-dimensional radiative transfer. In particular, we derive the gKM approximation for the problem of collimated beam propagation and scattering in a plane-parallel slab composed of a uniform absorbing and scattering medium. The result is an 8×8 system of partial differential equations that is much easier to solve than the radiative transfer equation. We compare the solutions of the gKM approximation with Monte Carlo simulations of the radiative transfer equation to identify the range of validity for this approximation. We find that the gKM approximation is accurate for isotropic scattering media that are sufficiently thick and much less accurate for anisotropic, forward-peaked scattering media.

  16. Spontaneous radiation and lamb shift in three-dimensional photonic crystals

    PubMed

    Zhu; Yang; Chen; Zheng; Zubairy

    2000-03-06

    Spontaneous emission in photonic crystals with anisotropic three-dimensional dispersion relation is studied. If the upper level is below a characteristic frequency omega(1), or above omega(2), or between omega(1) and omega(2), the radiation is a localized field with a frequency in the band gap, or a propagating field with a frquency in the band, or a diffusion field, respectively. An analytical expression for the Lamb shift is obtained. The Lamb shift for the current case is small compared to that in an ordinary vacuum or in one- or two-dimensional photonic crystals due to lower density of states.

  17. NOTE: Measurement of the three-dimensional distribution of radiation dose in grid therapy

    NASA Astrophysics Data System (ADS)

    Trapp, J. V.; Warrington, A. P.; Partridge, M.; Philps, A.; Glees, J.; Tait, D.; Ahmed, R.; Leach, M. O.; Webb, S.

    2004-10-01

    A single large dose of megavoltage x-rays delivered through a grid is currently being utilized by some centres for palliative radiotherapy treatments of large tumours. In this note, we investigate the dosimetry of grid therapy using two-dimensional film dosimetry and three-dimensional gel dosimetry. It is shown that the radiation dose is attenuated more rapidly with depth in a grid field than an open field, and that even shielded regions receive approximately 25% of the dose to the unshielded areas.

  18. Fast evaluation of Sommerfeld integrals for EM scattering and radiation by three-dimensional buried objects

    SciTech Connect

    Cui, T.J.; Chew, W.C.

    1999-03-01

    This paper presents a fast method for electromagnetic scattering and radiation problems pertinent to three-dimensional (3-D) buried objects. In this approach, a new symmetrical form of the Green`s function is derived, which can reduce the number of Sommerfeld integrals involved in the buried objects problem. The integration along steepest descent paths and leading-order approximations are introduced to evaluate these Sommerfeld integrals, which can greatly accelerate the computation. Based on the fast evaluation of Sommerfeld integrals, the radiation of an arbitrarily oriented electric dipole buried in a half space is first analyzed and computed. Then, the scattering by buried dielectric objects and conducting objects is considered using the method of moments (MOM). Numerical results show that the fast method can save tremendous CPU time in radiation and scattering problems involving buried objects.

  19. Electron energy loss and Smith-Purcell radiation in two- and three-dimensional photonic crystals

    NASA Astrophysics Data System (ADS)

    Ochiai, Tetsuyuki; Ohtaka, Kazuo

    2005-09-01

    A theoretical description of the electron energy loss and the Smith-Purcell radiation is presented for an electron moving near a two-dimensional photonic crystal slab and a three-dimensional woodpile photonic crystal. The electron energy loss and the Smith-Purcell radiation spectra are well correlated with the photonic band structures of these crystals and thus can be used as a probe of them. In particular, there is a selection rule concerning the symmetries of the photonic band modes to be excited when the electron moves in a mirror plane of the crystals. In the woodpile, a highly directional Smith-Purcell radiation is realized by using the planar defect mode inside the complete band gap.

  20. Electron energy loss and Smith-Purcell radiation in two- and three-dimensional photonic crystals.

    PubMed

    Ochiai, Tetsuyuki; Ohtaka, Kazuo

    2005-09-19

    A theoretical description of the electron energy loss and the Smith-Purcell radiation is presented for an electron moving near a two-dimensional photonic crystal slab and a three-dimensional woodpile photonic crystal. The electron energy loss and the Smith-Purcell radiation spectra are well correlated with the photonic band structures of these crystals and thus can be used as a probe of them. In particular, there is a selection rule concerning the symmetries of the photonic band modes to be excited when the electron moves in a mirror plane of the crystals. In the woodpile, a highly directional Smith-Purcell radiation is realized by using the planar defect mode inside the complete band gap.

  1. A fast method to compute Three-Dimensional Infrared Radiative Transfer in non scattering medium

    NASA Astrophysics Data System (ADS)

    Makke, Laurent; Musson-Genon, Luc; Carissimo, Bertrand

    2014-05-01

    The Atmospheric Radiation field has seen the development of more accurate and faster methods to take into account absoprtion in participating media. Radiative fog appears with clear sky condition due to a significant cooling during the night, so scattering is left out. Fog formation modelling requires accurate enough method to compute cooling rates. Thanks to High Performance Computing, multi-spectral approach of Radiative Transfer Equation resolution is most often used. Nevertheless, the coupling of three-dimensionnal radiative transfer with fluid dynamics is very detrimental to the computational cost. To reduce the time spent in radiation calculations, the following method uses analytical absorption functions fitted by Sasamori (1968) on Yamamoto's charts (Yamamoto,1956) to compute a local linear absorption coefficient. By averaging radiative properties, this method eliminates the spectral integration. For an isothermal atmosphere, analytical calculations lead to an explicit formula between emissivities functions and linear absorption coefficient. In the case of cooling to space approximation, this analytical expression gives very accurate results compared to correlated k-distribution. For non homogeneous paths, we propose a two steps algorithm. One-dimensional radiative quantities and linear absorption coefficient are computed by a two-flux method. Then, three-dimensional RTE under the grey medium assumption is solved with the DOM. Comparisons with measurements of radiative quantities during ParisFOG field (2006) shows the cability of this method to handle strong vertical variations of pressure/temperature and gases concentrations.

  2. Implementation of Localized Ensemble Assimilation for a Three-Dimensional Radiation Belt Model (Invited)

    NASA Astrophysics Data System (ADS)

    Godinez, H. C.; Chen, Y.; Kellerman, A. C.; Subbotin, D.; Shprits, Y.

    2013-12-01

    Earth's outer radiation belt is very dynamic and energetic electrons therein undergo constant changes due to acceleration, loss, and trans- port processes. In this work we improve the accuracy of simulated electron phase space density (PSD) of the Versatile Electron Radiation Belt (VERB) code, a three-dimensional radiation belt model, by implementing the localized ensemble transform Kalman filter (LETKF) assimilation method. Assimilation methods based on Kalman filtering have been successfully applied to one-dimensional radial diffusion radiation belt models, where it has been shown to greatly improve the model estimation of electron phase space density (PSD). This work expands upon previous research by implementing the LETKF method to assimilate observed electron density into VERB, a three-dimensional radiation belt model. In particular, the LETKF will perform the assimilation locally, where the size of the local region is defined by the diffusion of electrons in the model. This will enable the optimal assimilation of data throughout the model consistently with the flow of electrons. Two sets of assimilation experiments are presented. The first is an identical-twin experiment, where artificial data is generated from the same model, with the purpose of verifying the assimilation method. In the second set of experiments, real PSD observational data from missions such as CRRES and/or the Van Allen Probes are assimilated into VERB. The results show that data assimilation significantly improves the accuracy of the VERB model by efficiently including the available observations at the appropriate pitch angles, energy levels, and L-shell regions throughout the model.

  3. The Coupling of Finite Element and Integral Equation Representations for Efficient Three-Dimensional Modeling of Electromagnetic Scattering and Radiation

    NASA Technical Reports Server (NTRS)

    Cwik, Tom; Zuffada, Cinzia; Jamnejad, Vahraz

    1996-01-01

    Finite element modeling has proven useful for accurtely simulating scattered or radiated fields from complex three-dimensional objects whose geometry varies on the scale of a fraction of a wavelength.

  4. Magnetohydrodynamic three-dimensional flow of viscoelastic nanofluid in the presence of nonlinear thermal radiation

    NASA Astrophysics Data System (ADS)

    Hayat, T.; Muhammad, Taseer; Alsaedi, A.; Alhuthali, M. S.

    2015-07-01

    Magnetohydrodynamic (MHD) three-dimensional flow of couple stress nanofluid in the presence of thermophoresis and Brownian motion effects is analyzed. Energy equation subject to nonlinear thermal radiation is taken into account. The flow is generated by a bidirectional stretching surface. Fluid is electrically conducting in the presence of a constant applied magnetic field. The induced magnetic field is neglected for a small magnetic Reynolds number. Mathematical formulation is performed using boundary layer analysis. Newly proposed boundary condition requiring zero nanoparticle mass flux is employed. The governing nonlinear mathematical problems are first converted into dimensionless expressions and then solved for the series solutions of velocities, temperature and nanoparticles concentration. Convergence of the constructed solutions is verified. Effects of emerging parameters on the temperature and nanoparticles concentration are plotted and discussed. Skin friction coefficients and Nusselt number are also computed and analyzed. It is found that the thermal boundary layer thickness is an increasing function of radiative effect.

  5. Simulation of radiation effects on three-dimensional computer optical memories

    NASA Technical Reports Server (NTRS)

    Moscovitch, M.; Emfietzoglou, D.

    1997-01-01

    A model was developed to simulate the effects of heavy charged-particle (HCP) radiation on the information stored in three-dimensional computer optical memories. The model is based on (i) the HCP track radial dose distribution, (ii) the spatial and temporal distribution of temperature in the track, (iii) the matrix-specific radiation-induced changes that will affect the response, and (iv) the kinetics of transition of photochromic molecules from the colored to the colorless isomeric form (bit flip). It is shown that information stored in a volume of several nanometers radius around the particle's track axis may be lost. The magnitude of the effect is dependent on the particle's track structure.

  6. Simulation of radiation effects on three-dimensional computer optical memories.

    PubMed

    Moscovitch, M; Emfietzoglou, D

    1997-01-01

    A model was developed to simulate the effects of heavy charged-particle (HCP) radiation on the information stored in three-dimensional computer optical memories. The model is based on (i) the HCP track radial dose distribution, (ii) the spatial and temporal distribution of temperature in the track, (iii) the matrix-specific radiation-induced changes that will affect the response, and (iv) the kinetics of transition of photochromic molecules from the colored to the colorless isomeric form (bit flip). It is shown that information stored in a volume of several nanometers radius around the particle's track axis may be lost. The magnitude of the effect is dependent on the particle's track structure.

  7. Analysis of ionizing radiation-induced DNA damage and repair in three-dimensional human skin model system

    PubMed Central

    Su, Yanrong; Meador, Jarah A.; Geard, Charles R.; Balajee, Adayabalam S.

    2010-01-01

    Knowledge of cellular responses in tissue microenvironment is crucial for the accurate prediction of human health risks following chronic or acute exposure to ionizing radiation (IR). With this objective, we investigated the radio responses for the first time in three-dimensional (3D) artificial human skin tissue microenvironment after γ-rays radiation. IR-induced DNA damage/repair response was assessed by immunological analysis of well-known DNA double strand break (DSB) repair proteins, i.e. 53BP1 and phosphorylated ataxia telangiectasia mutatedser1981 (ATMser1981). Efficient 53BP1 and phosphorylated ATM foci formation was observed in human EpiDerm tissue constructs after low and high doses of γ-rays. Interestingly, EpiDerm tissue constructs displayed less 53BP1 and ATM foci number at all radiation doses (0.1, 1, 2.5 and 5 Gy) than that observed for 2D human fibroblasts. DSB repair efficiency judged by the disappearance of 53BP1 foci declined with increasing doses of γ-rays and tissue constructs irradiated with 2.5 and 5 Gy of γ-rays displayed 53BP1 foci persisting up to 72 h of analysis. Pretreatment of EpiDerm tissue constructs with LY294002, [an inhibitor of phosphatidylinositol-3 kinase and PI-3 kinase like kinases (PIKK)] completely abolished IR-induced 53BP1 foci formation and increased the apoptotic death. This observation indicates the importance of PIKK signalling pathway for efficient radiation responses in intact tissue constructs. In summary, we have successfully demonstrated the feasibility of monitoring the DNA damage response in human skin tissue microenvironment. In this system, 53BP1 can be used as a useful marker for monitoring the DSB repair efficiency. PMID:19650866

  8. Analysis of ionizing radiation-induced DNA damage and repair in three-dimensional human skin model system.

    PubMed

    Su, Yanrong; Meador, Jarah A; Geard, Charles R; Balajee, Adayabalam S

    2010-08-01

    Knowledge of cellular responses in tissue microenvironment is crucial for the accurate prediction of human health risks following chronic or acute exposure to ionizing radiation (IR). With this objective, we investigated the radio responses for the first time in three-dimensional (3D) artificial human skin tissue microenvironment after gamma-rays radiation. IR-induced DNA damage/repair response was assessed by immunological analysis of well-known DNA double strand break (DSB) repair proteins, i.e. 53BP1 and phosphorylated ataxia telangiectasia mutated(ser1981) (ATM(ser1981)). Efficient 53BP1 and phosphorylated ATM foci formation was observed in human EpiDerm tissue constructs after low and high doses of gamma-rays. Interestingly, EpiDerm tissue constructs displayed less 53BP1 and ATM foci number at all radiation doses (0.1, 1, 2.5 and 5 Gy) than that observed for 2D human fibroblasts. DSB repair efficiency judged by the disappearance of 53BP1 foci declined with increasing doses of gamma-rays and tissue constructs irradiated with 2.5 and 5 Gy of gamma-rays displayed 53BP1 foci persisting up to 72 h of analysis. Pretreatment of EpiDerm tissue constructs with LY294002, [an inhibitor of phosphatidylinositol-3 kinase and PI-3 kinase like kinases (PIKK)] completely abolished IR-induced 53BP1 foci formation and increased the apoptotic death. This observation indicates the importance of PIKK signalling pathway for efficient radiation responses in intact tissue constructs. In summary, we have successfully demonstrated the feasibility of monitoring the DNA damage response in human skin tissue microenvironment. In this system, 53BP1 can be used as a useful marker for monitoring the DSB repair efficiency.

  9. A global three-dimensional radiation magneto-hydrodynamic simulation of super-eddington accretion disks

    SciTech Connect

    Jiang, Yan-Fei; Stone, James M.; Davis, Shane W.

    2014-12-01

    We study super-Eddington accretion flows onto black holes using a global three-dimensional radiation magneto-hydrodynamical simulation. We solve the time-dependent radiative transfer equation for the specific intensities to accurately calculate the angular distribution of the emitted radiation. Turbulence generated by the magneto-rotational instability provides self-consistent angular momentum transfer. The simulation reaches inflow equilibrium with an accretion rate ∼220 L {sub Edd}/c {sup 2} and forms a radiation-driven outflow along the rotation axis. The mechanical energy flux carried by the outflow is ∼20% of the radiative energy flux. The total mass flux lost in the outflow is about 29% of the net accretion rate. The radiative luminosity of this flow is ∼10 L {sub Edd}. This yields a radiative efficiency ∼4.5%, which is comparable to the value in a standard thin disk model. In our simulation, vertical advection of radiation caused by magnetic buoyancy transports energy faster than photon diffusion, allowing a significant fraction of the photons to escape from the surface of the disk before being advected into the black hole. We contrast our results with the lower radiative efficiencies inferred in most models, such as the slim disk model, which neglect vertical advection. Our inferred radiative efficiencies also exceed published results from previous global numerical simulations, which did not attribute a significant role to vertical advection. We briefly discuss the implications for the growth of supermassive black holes in the early universe and describe how these results provided a basis for explaining the spectrum and population statistics of ultraluminous X-ray sources.

  10. A Global Three-dimensional Radiation Magneto-hydrodynamic Simulation of Super-Eddington Accretion Disks

    NASA Astrophysics Data System (ADS)

    Jiang, Yan-Fei; Stone, James M.; Davis, Shane W.

    2014-12-01

    We study super-Eddington accretion flows onto black holes using a global three-dimensional radiation magneto-hydrodynamical simulation. We solve the time-dependent radiative transfer equation for the specific intensities to accurately calculate the angular distribution of the emitted radiation. Turbulence generated by the magneto-rotational instability provides self-consistent angular momentum transfer. The simulation reaches inflow equilibrium with an accretion rate ~220 L Edd/c 2 and forms a radiation-driven outflow along the rotation axis. The mechanical energy flux carried by the outflow is ~20% of the radiative energy flux. The total mass flux lost in the outflow is about 29% of the net accretion rate. The radiative luminosity of this flow is ~10 L Edd. This yields a radiative efficiency ~4.5%, which is comparable to the value in a standard thin disk model. In our simulation, vertical advection of radiation caused by magnetic buoyancy transports energy faster than photon diffusion, allowing a significant fraction of the photons to escape from the surface of the disk before being advected into the black hole. We contrast our results with the lower radiative efficiencies inferred in most models, such as the slim disk model, which neglect vertical advection. Our inferred radiative efficiencies also exceed published results from previous global numerical simulations, which did not attribute a significant role to vertical advection. We briefly discuss the implications for the growth of supermassive black holes in the early universe and describe how these results provided a basis for explaining the spectrum and population statistics of ultraluminous X-ray sources.

  11. Apparatus and method for high dose rate brachytherapy radiation treatment

    DOEpatents

    Macey, Daniel J.; Majewski, Stanislaw; Weisenberger, Andrew G.; Smith, Mark Frederick; Kross, Brian James

    2005-01-25

    A method and apparatus for the in vivo location and tracking of a radioactive seed source during and after brachytherapy treatment. The method comprises obtaining multiple views of the seed source in a living organism using: 1) a single PSPMT detector that is exposed through a multiplicity of pinholes thereby obtaining a plurality of images from a single angle; 2) a single PSPMT detector that may obtain an image through a single pinhole or a plurality of pinholes from a plurality of angles through movement of the detector; or 3) a plurality of PSPMT detectors that obtain a plurality of views from different angles simultaneously or virtually simultaneously. The plurality of images obtained from these various techniques, through angular displacement of the various acquired images, provide the information required to generate the three dimensional images needed to define the location of the radioactive seed source within the body of the living organism.

  12. Three-dimensional aspects of radiative transfer in remote sensing of precipitation: Application to the 1986 COHMEX storm

    NASA Technical Reports Server (NTRS)

    Haferman, J. L.; Krajewski, W. F.; Smith, T. F.

    1994-01-01

    Several multifrequency techniques for passive microwave estimation of precipitation based on the absorption and scattering properties of hydrometers have been proposed in the literature. In the present study, plane-parallel limitations are overcome by using a model based on the discrete-ordinates method to solve the radiative transfer equation in three-dimensional rectangular domains. This effectively accounts for the complexity and variety of radiation problems encountered in the atmosphere. This investigation presents result for plane-parallel and three-dimensional radiative transfer for a precipitating system, discusses differences between these results, and suggests possible explanations for these differences. Microphysical properties were obtained from the Colorado State University Regional Atmospehric Modeling System and represent a hailstorm observed during the 1986 Cooperative Huntsville Meteorological Experiment. These properties are used as input to a three-dimensional radiative transfer model in order to simulate satellite observation of the storm. The model output consists of upwelling brightness temperatures at several of the frequencies on the Special Sensor Microwave/Imager. The radiative transfer model accounts for scattering and emission of atmospheric gases and hydrometers in liquid and ice phases. Brightness temperatures obtained from the three-dimensional model of this investigation indicate that horizontal inhomogeneities give rise to brightness temperature fields that can be quite different from fields obtained using plane-parallel radiative transfer theory. These differences are examined for various resolutions of the satellite sensor field of view. In adddition, the issue of boundary conditions for three-dimensional atmospheric radiative transfer is addressed.

  13. Australian and New Zealand three-dimensional conformal radiation therapy consensus guidelines for prostate cancer.

    PubMed

    Skala, M; Berry, M; Duchesne, G; Gogna, K; Tai, K-H; Turner, S; Kneebone, A; Rolfo, A; Haworth, A

    2004-12-01

    Three-dimensional conformal radiation therapy (3DCRT) has been shown to reduce normal tissue toxicity and allow dose escalation in the curative treatment of prostate cancer. The Faculty of Radiation Oncology Genito-Urinary Group initiated a consensus process to generate evidence-based guidelines for the safe and effective implementation of 3DCRT. All radiation oncology departments in Australia and New Zealand were invited to complete a survey of their prostate practice and to send representatives to a consensus workshop. After a review of the evidence, key issues were identified and debated. If agreement was not reached, working parties were formed to make recommendations. Draft guidelines were circulated to workshop participants for approval prior to publication. Where possible, evidence-based recommendations have been made with regard to patient selection, risk stratification, simulation, planning, treatment delivery and toxicity reporting. This is the first time a group of radiation therapists, physicists and oncologists representing professional radiotherapy practice across Australia and New Zealand have worked together to develop best-practice guidelines. These guidelines should serve as a baseline for prospective clinical trials, outcome research and quality assurance.

  14. Impact of thermophoresis particle deposition on three-dimensional radiative flow of Burgers fluid

    NASA Astrophysics Data System (ADS)

    Khan, Waqar Azeem; Khan, Masood

    This paper explores the analytical solution to heat and mass transfer of a three-dimensional steady flow of Burgers fluid over a bidirectional stretching surface. Additionally, analysis is carried out in the presence of thermal radiation, heat generation/absorption and thermophoretic effects. The governing non-linear problem is developed and transformed into self-similar form by utilizing similarity approach. The resulting non-linear problem is solved analytically by employing the homotpy analysis method (HAM). The obtained results are plotted and discussed in detail for interesting physical parameters. It is seen that increasing values of the thermophoretic parameter leads to a decrease in the concentration field and the corresponding concentration boundary layer thickness. Also, it is noticed that the concentration field decays quickly corresponding with thermophoretic parameter in comparison to Schmidt number.

  15. Scattering and radiation analysis of three-dimensional cavity arrays via a hybrid finite element method

    NASA Technical Reports Server (NTRS)

    Jin, Jian-Ming; Volakis, John L.

    1992-01-01

    A hybrid numerical technique is presented for a characterization of the scattering and radiation properties of three-dimensional cavity arrays recessed in a ground plane. The technique combines the finite element and boundary integral methods and invokes Floquet's representation to formulate a system of equations for the fields at the apertures and those inside the cavities. The system is solved via the conjugate gradient method in conjunction with the Fast Fourier Transform (FFT) thus achieving an O(N) storage requirement. By virtue of the finite element method, the proposed technique is applicable to periodic arrays comprised of cavities having arbitrary shape and filled with inhomogeneous dielectrics. Several numerical results are presented, along with new measured data, which demonstrate the validity, efficiency, and capability of the technique.

  16. Very High Dose-Rate Radiobiology and Radiation Therapy for Lung Cancer

    DTIC Science & Technology

    2015-02-01

    AWARD NUMBER: W81XWH-14-1-0014 TITLE: Very High Dose-Rate Radiobiology and Radiation Therapy for Lung Cancer PRINCIPAL INVESTIGATOR: Peter Maxim...TITLE AND SUBTITLE ery High Dose-Rate Radiobiology and Radiation Therapy for Lung Cancer 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-14-1-0014 5c...1 Contract number: W81XWH-14-1-0014 Title: Very High Dose-Rate Radiobiology and Radiation Therapy for Lung Cancer Principal Investigator: Peter G

  17. Three-Dimensional Mixed Convection Flow of Viscoelastic Fluid with Thermal Radiation and Convective Conditions

    PubMed Central

    Hayat, Tasawar; Ashraf, Muhammad Bilal; Alsulami, Hamed H.; Alhuthali, Muhammad Shahab

    2014-01-01

    The objective of present research is to examine the thermal radiation effect in three-dimensional mixed convection flow of viscoelastic fluid. The boundary layer analysis has been discussed for flow by an exponentially stretching surface with convective conditions. The resulting partial differential equations are reduced into a system of nonlinear ordinary differential equations using appropriate transformations. The series solutions are developed through a modern technique known as the homotopy analysis method. The convergent expressions of velocity components and temperature are derived. The solutions obtained are dependent on seven sundry parameters including the viscoelastic parameter, mixed convection parameter, ratio parameter, temperature exponent, Prandtl number, Biot number and radiation parameter. A systematic study is performed to analyze the impacts of these influential parameters on the velocity and temperature, the skin friction coefficients and the local Nusselt number. It is observed that mixed convection parameter in momentum and thermal boundary layers has opposite role. Thermal boundary layer is found to decrease when ratio parameter, Prandtl number and temperature exponent are increased. Local Nusselt number is increasing function of viscoelastic parameter and Biot number. Radiation parameter on the Nusselt number has opposite effects when compared with viscoelastic parameter. PMID:24608594

  18. Evaluating a three dimensional model of diffuse photosynthetically active radiation in maize canopies

    NASA Astrophysics Data System (ADS)

    Wang, Xiping; Guo, Yan; Li, Baoguo; Wang, Xiyong; Ma, Yuntao

    2006-07-01

    Diffuse photosynthetically active radiation (DPAR) is important during overcast days and for plant parts shaded from the direct beam radiation. Simulation of DPAR interception by individual plant parts of a canopy, separately from direct beam photosynthetically active radiation (PAR), may give important insights into plant ecology. This paper presents a model to simulate the interception of DPAR in plant canopies. A sub-model of a virtual maize canopy was reconstructed. Plant surfaces were represented as small triangular facets positioned according to three-dimensionally (3D) digitized data collected in the field. Then a second sub-model to simulate the 3D DPAR distribution in the canopy was developed by dividing the sky hemisphere into a grid of fine cells that allowed for the anisotropic distribution of DPAR over the sky hemisphere. This model, DSHP (Dividing Sky Hemisphere with Projecting), simulates which DSH (Divided Sky Hemisphere) cells are directly visible from a facet in the virtual canopy, i.e. not obscured by other facets. The DPAR reaching the center of a facet was calculated by summing the amounts of DPAR present in every DSH cell. The distribution of DPAR in a canopy was obtained from the calculated DPARs intercepted by all facets in the canopy. This DSHP model was validated against DPAR measurements made in an actual maize ( Zea mays L.) canopy over selected days during the early filling stage. The simulated and measured DPAR at different canopy depths showed a good agreement with a R 2 equaling 0.78 ( n=120).

  19. Observations of Three-Dimensional Radiative Effects that Influence Satellite Retrievals of Cloud Properties

    NASA Technical Reports Server (NTRS)

    Varnai, Tamas; Marshak, Alexander; Lau, William K. M. (Technical Monitor)

    2001-01-01

    This paper examines three-dimensional (3D) radiative effects, which arise from horizontal radiative interactions between areas that have different cloud properties. Earlier studies have argued that these effects can cause significant uncertainties in current satellite retrievals of cloud properties, because the retrievals rely on one-dimensional (1D) theory and do not consider the effects of horizontal changes in cloud properties. This study addresses two questions: which retrieved cloud properties are influenced by 3D radiative effects, and where 3D effects tend to occur? The influence of 3D effects is detected from the wayside illumination and shadowing make clouds appear asymmetric: Areas appear brighter if the cloud top surface is tilted toward, rather than away from, the Sun. The analysis of 30 images by the Moderate Resolution Imaging Spectroradiometer (MODIS) reveals that retrievals of cloud optical thickness and cloud water content are most influenced by 3D effects, whereas retrievals of cloud particle size are much less affected. The results also indicate that while 3D effects are strongest at cloud edges, cloud top variability in cloud interiors, even in overcast regions, also produces considerable 3D effects. Finally, significant 3D effects are found in a wide variety of situations, ranging from thin clouds to thick ones and from low clouds to high ones.

  20. Three-dimensional mixed convection flow of viscoelastic fluid with thermal radiation and convective conditions.

    PubMed

    Hayat, Tasawar; Ashraf, Muhammad Bilal; Alsulami, Hamed H; Alhuthali, Muhammad Shahab

    2014-01-01

    The objective of present research is to examine the thermal radiation effect in three-dimensional mixed convection flow of viscoelastic fluid. The boundary layer analysis has been discussed for flow by an exponentially stretching surface with convective conditions. The resulting partial differential equations are reduced into a system of nonlinear ordinary differential equations using appropriate transformations. The series solutions are developed through a modern technique known as the homotopy analysis method. The convergent expressions of velocity components and temperature are derived. The solutions obtained are dependent on seven sundry parameters including the viscoelastic parameter, mixed convection parameter, ratio parameter, temperature exponent, Prandtl number, Biot number and radiation parameter. A systematic study is performed to analyze the impacts of these influential parameters on the velocity and temperature, the skin friction coefficients and the local Nusselt number. It is observed that mixed convection parameter in momentum and thermal boundary layers has opposite role. Thermal boundary layer is found to decrease when ratio parameter, Prandtl number and temperature exponent are increased. Local Nusselt number is increasing function of viscoelastic parameter and Biot number. Radiation parameter on the Nusselt number has opposite effects when compared with viscoelastic parameter.

  1. Successful catheter ablation of incessant atrial tachycardia in pregnancy using three-dimensional electroanatomical mapping with minimal radiation.

    PubMed

    Wu, H; Ling, L-H; Lee, G; Kistler, P M

    2012-06-01

    Arrhythmias during pregnancy are not an infrequent problem and present a difficult therapeutic challenge to physicians. Anti-arrhythmic medication is used with some trepidation given concerns for the unborn foetus. Catheter ablation is typically avoided due to concerns regarding foetal exposure to radiation and delayed until the post-partum period. With the availability of three-dimensional mapping systems, catheter ablation may be performed with minimal radiation. We report a pregnant woman who underwent successful ablation of focal atrial tachycardia using three-dimensional electroanatomical mapping with minimal radiation exposure.

  2. Implementation of Ensemble Data Assimilation for a Three-Dimensional Radiation Belt Model

    NASA Astrophysics Data System (ADS)

    Godinez, H. C.; Chen, Y.; Shprits, Y.; Kellerman, A. C.; Subbotin, D.

    2013-05-01

    Earth's outer radiation belt is very dynamic and undergoes constant changes due to acceleration, loss, and transport processes of the energetic electrons. In this work the ensemble Kalman filter (EnKF) assimilation method is applied to the Versatile Electron Radiation Belt (VERB) code, a three-dimensional radiation belt model developed at the University of California Los Angeles. The VERB model includes radial, pitch angle, and energy diffusion caused by low-latitude and high-latitude chorus, plasma- spheric hiss, and electromagnetic ion cyclotron (EMIC) waves. Assimi- lation methods based on Kalman filtering have been successfully applied to one-dimensional radial diffusion radiation belt models, where it has been shown that assimilating real observational data into the radiation belt models greatly improves the accuracy of electron PSD estimation. In our work we implement the EnKF for assimilation of real electron PSD data into the VERB model. In particular the assimilation is performed locally along the direction of the dominant diffusion of electrons in the model. This will enable the correct assimilation of data to be consistent with the flow of electrons throughout the model. Two set of assimila- tion experiments are presented. The first is an identical-twin experiment, where artificial data is generated from the same model, with the purpose of validating the assimilation method. In the second set of experiments, real PSD observational data from CRRES are assimilated into VERB in order to improve the model estimation of the electron PSD distribution. The results show that data assimilation significantly improves the accu- racy of the VERB model by efficiently including observations to correct the model PSD estimation.

  3. Three-dimensional simulation of wave-induced circulation: Comparison of three radiation stress formulations

    NASA Astrophysics Data System (ADS)

    Sheng, Y. Peter; Liu, Tianyi

    2011-05-01

    A three-dimensional current-wave modeling system, Curvilinear-grid Hydrodynamics 3D (CH3D)-Simulating Waves Nearshore (SWAN), has been used to simulate wave-induced circulation and compare the performances of three radiation stress (RS) formulations: two depth-dependent formulations (M08 by Mellor (2008) and X04 by Xia et al. (2004)) and one depth-independent formulation (LHS by Longuet-Higgins and Stewart (1964)). While all are based on linear wave theory, LHS uses the vertically integrated equations of motion, and M08 and X04 consider the three-dimensional equations of motion. Results of CH3D-SWAN with three RS formulations are compared with steady state wave setup, observed data in an undertow experiment by Ting and Kirby (1994) (TK94), and observed data in a laboratory fringing reef. All three RS formulations reproduce the analytical solution of wave setup very well. Simulated wave-induced currents and turbulence for TK94 are the best when M08 is used and worst when X04 is used, apparently due to the errors in the X04 formulation. All three RS formulations give good simulation of wave setup in the fringing reef. Wave-induced currents in the fringing reef simulated by the three RS formulations are quite different: M08 produces a single large clockwise gyre in the x-z plane, LHS produces a weaker gyre, and X04 produces a clockwise gyre plus a counterclockwise gyre inside the surf zone. Using the CH3D-Storm Surge Modeling System and M08, storm surge and currents in the Outer Banks and Chesapeake Bay during Hurricane Isabel are simulated. Compared to the earlier simulation obtained with the LHS, M08 produces similar storm surge but slightly improved the wave-induced currents.

  4. Three-dimensional radiation dose mapping with the TORT computer code

    SciTech Connect

    Slater, C.O.; Pace, J.V. III; Childs, R.L.; Haire, M.J. ); Koyama, T. )

    1991-01-01

    The Consolidated Fuel Reprocessing Program (CFRP) at Oak Ridge National Laboratory (ORNL) has performed radiation shielding studies in support of various facility designs for many years. Computer codes employing the point-kernel method have been used, and the accuracy of these codes is within acceptable limits. However, to further improve the accuracy and to calculate dose at a larger number of locations, a higher order method is desired, even for analyses performed in the early stages of facility design. Consequently, the three-dimensional discrete ordinates transport code TORT, developed at ORNL in the mid-1980s, was selected to examine in detail the dose received at equipment locations. The capabilities of the code have been previously reported. Recently, the Power Reactor and Nuclear Fuel Development Corporation in Japan and the US Department of Energy have used the TORT code as part of a collaborative agreement to jointly develop breeder reactor fuel reprocessing technology. In particular, CFRP used the TORT code to estimate radiation dose levels within the main process cell for a conceptual plant design and to establish process equipment lifetimes. The results reported in this paper are for a conceptual plant design that included the mechanical head and (i.e., the disassembly and shear machines), solvent extraction equipment, and miscellaneous process support equipment.

  5. Can we afford three-dimensional radiative transfer in NWP and LES models?

    NASA Astrophysics Data System (ADS)

    Jakub, Fabian; Mayer, Bernhard

    2014-05-01

    Next generation NWP models shift from statistical cloud parametrizations to physics based convection, by increasing the spatial resolution to considerably less than 1km. The calculation of atmospheric heating rates still relies heavily on one dimensional schemes (independent column approximation, ICA), although recent studies showed that three dimensional radiative heating rates may have considerable impact on clouds and precipitation. Simple approximations such as the ICA are needed because of the extraordinary computational burden of known 3D radiative transfer operators (Monte Carlo based or SHDOM) which makes the assessment of 3D RT-effects on cloud dynamics cumbersome. Thus, to date NWP/LES simulations which include 3D RT effects are only performed for limited time periods and domain sizes. In order to study the full extent of 3D RT effects a fresh approach is needed: We present a new RT-scheme which compares well in computational speed to currently employed 1D-schemes whilst incorporating principal 3D-effects. Special emphasis in the development of such a RT-scheme has to be laid on the calculation of atmospheric heating rates. Furthermore the scalability on massively parallel computers is mandatory.

  6. Global three-dimensional simulation and radiative forcing of various aerosol species with GCM

    NASA Astrophysics Data System (ADS)

    Takemura, Toshihiko; Okamoto, Hajime; Numaguti, Atusi; Suzuki, Kentaroh; Higurashi, Akiko; Nakajima, Teruyuki

    2001-02-01

    A global three-dimensional transport model that can simultaneously treat main tropospheric aerosols, i.e., carbonaceous (organic and black carbons), sulfate, soil dust, and sea salt, is developed. It is coupled with a Center for Climate System Research (CCSR)/National Institute for Enviormental Studies (NIES) atmospheric general circulation model (AGCM), and the meteorological field of wind, temperature, and specific humidity can be nudged by reanalysis data. Simulated results are compared with not only observations for aerosol concentrations but also the optical thickness and Angstrom exponent retrieved from remote sensing data such as National Oceanic and Atmospheric Administration (NOAA)/Advanced Very High Resolution Radiometer (AVHRR) and Aerosol Robotic Network (AERONET). A general agreement is found between simulated results and observations spatially seasonally, and quantitatively. The present model is also coupled with the radiative process over both the solar and thermal regions. The annual and global mean radiative forcing by anthropogenic aerosols from fossil fuel sources is estimated to be -0.5 W m-2 over the clear sky for the direct effect and -2.0 W m-2 for the indirect effect.

  7. PAKAL: A THREE-DIMENSIONAL MODEL TO SOLVE THE RADIATIVE TRANSFER EQUATION

    SciTech Connect

    De la Luz, Victor; Lara, Alejandro; Mendoza-Torres, J. E.; Selhorst, Caius L.

    2010-06-15

    We present a new numerical model called 'Pakal' intended to solve the radiative transfer equation in a three-dimensional (3D) geometry, using the approximation for a locally plane-parallel atmosphere. Pakal uses pre-calculated radial profiles of density and temperature (based on hydrostatic, hydrodynamic, or MHD models) to compute the emission from 3D source structures with high spatial resolution. Then, Pakal solves the radiative transfer equation in a set of (3D) ray paths, going from the source to the observer. Pakal uses a new algorithm to compute the radiative transfer equation by using an intelligent system consisting of three structures: a cellular automaton; an expert system; and a program coordinator. The code outputs can be either two-dimensional maps or one-dimensional profiles, which reproduce the observations with high accuracy, giving detailed physical information about the environment where the radiation was generated and/or transmitted. We present the model applied to a 3D solar radial geometry, assuming a locally plane-parallel atmosphere, and thermal free-free radio emission from hydrogen-helium gas in thermodynamic equilibrium. We also present the convergence test of the code. We computed the synthetic spectrum of the centimetric-millimetric solar emission and found better agreement with observations (up to 10{sup 4} K at 20 GHz) than previous models reported in the literature. The stability and convergence test show the high accuracy of the code. Finally, Pakal can improve the integration time by up to an order of magnitude compared against linear integration codes.

  8. Pakal: A Three-dimensional Model to Solve the Radiative Transfer Equation

    NASA Astrophysics Data System (ADS)

    De la Luz, Victor; Lara, Alejandro; Mendoza-Torres, J. E.; Selhorst, Caius L.

    2010-06-01

    We present a new numerical model called "Pakal" intended to solve the radiative transfer equation in a three-dimensional (3D) geometry, using the approximation for a locally plane-parallel atmosphere. Pakal uses pre-calculated radial profiles of density and temperature (based on hydrostatic, hydrodynamic, or MHD models) to compute the emission from 3D source structures with high spatial resolution. Then, Pakal solves the radiative transfer equation in a set of (3D) ray paths, going from the source to the observer. Pakal uses a new algorithm to compute the radiative transfer equation by using an intelligent system consisting of three structures: a cellular automaton; an expert system; and a program coordinator. The code outputs can be either two-dimensional maps or one-dimensional profiles, which reproduce the observations with high accuracy, giving detailed physical information about the environment where the radiation was generated and/or transmitted. We present the model applied to a 3D solar radial geometry, assuming a locally plane-parallel atmosphere, and thermal free-free radio emission from hydrogen-helium gas in thermodynamic equilibrium. We also present the convergence test of the code. We computed the synthetic spectrum of the centimetric-millimetric solar emission and found better agreement with observations (up to 104 K at 20 GHz) than previous models reported in the literature. The stability and convergence test show the high accuracy of the code. Finally, Pakal can improve the integration time by up to an order of magnitude compared against linear integration codes.

  9. High-dose fractionated radiation therapy for select patients with brain metastases

    SciTech Connect

    Pezner, R.D.; Lipsett, J.A.; Archambeau, J.O.; Fine, R.M.; Moss, W.T.

    1981-08-01

    Four patients with metastases to the brain were treated by high-dose fractionated radiation therapy. In all four cases, a complete response and prolonged disease-free survival could be documented. Unlike the standard therapy for such patients (i.e., craniotomy and postoperative irradiation), high-dose fractionated radiation therapy carries no operative risk and can encompass multiple brain metastases and metastases in deep or critical intracranial sites. The risk of radiotherapy side effects in the brain is discussed.

  10. Two- and three-dimensional models for risk assessment of radiation-enhanced colorectal tumorigenesis.

    PubMed

    Roig, Andres I; Hight, Suzie K; Shay, Jerry W

    2009-01-01

    Astronauts may be at an increased risk for developing colorectal cancer after a prolonged interplanetary mission given the potential for greater carcinogenic effects of radiation to the colon. In addition, with an increase in age, there is a greater incidence of premalignant colon adenomas with age. In the present study, we have compared the effects of radiation on human colon epithelial cells in two-dimensional (2D) monolayer culture, in three-dimensional (3D) culture, and in intact human colon tissue biopsies. Immortalized colon epithelial cells were irradiated at the NASA Space Radiation Laboratory (NSRL) with either 1 Gy 1 GeV/nucleon (56)Fe particles or 1 Gy 1 GeV/nucleon protons and were stained at various times to assess DNA damage and repair responses. The results show more persisting damage at 24 h with iron-particle radiation compared to protons. Similar results were seen in 3D colon epithelial cell cultures in which (56)Fe-particle-irradiated specimens show more persisting damage at 24 h than those irradiated with low-LET gamma rays. We compared these results to those obtained from human colon tissue biopsies irradiated with 1 Gy gamma rays or 1 Gy 1 GeV (56)Fe particles. Observations of radiation-induced DNA damage and repair in gamma-irradiated specimens revealed more pronounced early DNA damage responses in the epithelial cell compartment compared to the stromal cell compartment. After low-LET irradiation, the damage foci mostly disappeared at 24 h. Antibodies to more than one type of DNA repair factor display this pattern of DNA damage, and staining of nonirradiated cells with nonphosphorylated DNA-PKcs shows a predominance of epithelial staining over stromal cells. Biopsy specimens irradiated with high-LET radiations also show a pattern of predominance of the DNA damage response in the highly proliferative epithelial cell compartment. Persistent unrepaired DNA damage in colon epithelial cells and the differing repair responses between the epithelial

  11. Behavioral Incapacitation from a High Dose of Ionizing Radiation

    DTIC Science & Technology

    1993-11-01

    1983. (UNCLASSIFIED) SMcMillan, G., Falkenberg , S., and Thompson, WI Early behavioral effects of ionizing radiation on fou• r species pf subhuman...aspect of Os, collection of iformatlort, indudkg Suggestions for reducing ttds burden, to Wahs ton HeadQuarters Services Directoralte f r infomratlon...wiere employed at the AFRRI in 1981 when the research was completed. R . W. Young and C. G. Franz were investigators in the Behavioral Science Department

  12. High Dose Gamma Radiation Selectively Reduces GABAA-slow Inhibition

    PubMed Central

    Dagne, Beza A; Sunay, Melis K; Cayla, Noëlie S; Ouyang, Yi-Bing; Knox, Susan J; Giffard, Rona G; Adler, John R.

    2017-01-01

    Studies on the effects of gamma radiation on brain tissue have produced markedly differing results, ranging from little effect to major pathology, following irradiation. The present study used control-matched animals to compare effects on a well characterized brain region following gamma irradiation. Male Sprague-Dawley rats were exposed to 60 Gy of whole brain gamma radiation and, after 24-hours, 48-hours, and one-week periods, hippocampal brain slices were isolated and measured for anatomical and physiological differences. There were no major changes observed in tissue appearance or evoked synaptic responses at any post-irradiation time point. However, exposure to 60 Gy of irradiation resulted in a small, but statistically significant (14% change; ANOVA p < 0.005; n = 9) reduction in synaptic inhibition seen at 100 ms, indicating a selective depression of the gamma-aminobutyric acid (GABAA) slow form of inhibition. Population spike (PS) amplitudes also transiently declined by ~ 10% (p < 0.005; n = 9) when comparing the 24-hour group to sham group. Effects on PS amplitude recovered to baseline 48 hour and one week later. There were no obvious negative pathological effects; however, a subtle depression in circuit level inhibition was observed and provides evidence for ‘radiomodulation’ of brain circuits. PMID:28401026

  13. Three-dimensional Čerenkov tomography of energy deposition from ionizing radiation beams.

    PubMed

    Glaser, Adam K; Voigt, William H A; Davis, Scott C; Zhang, Rongxiao; Gladstone, David J; Pogue, Brian W

    2013-03-01

    Since its discovery during the 1930s the Čerenkov effect (light emission from charged particles traveling faster than the local speed of light in a dielectric medium) has been paramount in the development of high-energy physics research. The ability of the emitted light to describe a charged particle's trajectory, energy, velocity, and mass has allowed scientists to study subatomic particles, detect neutrinos, and explore the properties of interstellar matter. However, to our knowledge, all applications of the process to date have focused on the identification of particles themselves, rather than their effect upon the surroundings through which they travel. Here we explore a novel application of the Čerenkov effect for the recovery of the spatial distribution of ionizing radiation energy deposition in a medium and apply it to the issue of dose determination in medical physics. By capturing multiple projection images of the Čerenkov light induced by a medical linear accelerator x-ray photon beam, we demonstrate the successful three-dimensional tomographic reconstruction of the imparted dose distribution.

  14. Monte Carlo Three-dimensional Radiative Transfer Modelling of Off Axis Situations

    NASA Astrophysics Data System (ADS)

    Friedeburg, C. V.; Morgner, A.; Wagner, T.; Wenig, M.; Platt, U.

    Off-Axis DOAS measurements with non-artificial scattered light, based upon the renowned DOAS technique, allow to optimize the sensitivity of the technique for the trace gas profile in question by strongly increasing the light's path through the relevant atmosphere layers. Multi-Axis-(MAX) DOAS probe several directions simultaneously or sequentially to increase the spatial resolution. Several devices (ground based, air- borne and ship-built) are operated by our group in the framework of the SCIAMACHY validation. Radiative transfer models are an essential requirement for the interpretation of these measurements and their conversion into detailed profile data. Apart from some existing Monte Carlo Models most codes use analytical algorithms to solve the radia- tive transfer equation for given atmospheric conditions. For specific circumstances, e.g. photon scattering within clouds, these approaches are not efficient enough to pro- vide sufficient accuracy. Also horizontal gradients in atmospheric parameters have to be taken into account. To meet the needs of measurement situations for all kinds of scattered light DOAS platforms, a three dimensional full spherical Monte Carlo model was devised. Here we present Air Mass Factors (AMF) to calculate vertical column densities (VCD) from measured slant column densities (SCD). Sensitivity studies on the influence of the wavelength and telescope direction used, of the altitude of profile layers, albedo, refraction and basic aerosols are shown. Also modelled intensity series are compared with radiometer data.

  15. Design and testing of indigenous cost effective three dimensional radiation field analyser (3D RFA).

    PubMed

    Ganesh, K M; Pichandi, A; Nehru, R M; Ravikumar, M

    2014-06-01

    The aim of the study is to design and validate an indigenous three dimensional Radiation Field Analyser (3D RFA). The feed system made for X, Y and Z axis movements is of lead screw with deep ball bearing mechanism made up of stain less steel driven by stepper motors with accuracy less than 0.5 mm. The telescopic column lifting unit was designed using linear actuation technology for lifting the water phantom. The acrylic phantom with dimensions of 800 x 750 x 570 mm was made with thickness of 15 mm. The software was developed in visual basic programming language, classified into two types, viz. beam analyzer software and beam acquisition software. The premeasurement checks were performed as per TG 106 recommendations. The physical parameters of photon PDDs such as Dmax, D10, D20 and Quality Index (QI), and the electron PDDs such as R50, Rp, E0, Epo and X-ray contamination values can be obtained instantaneously by using the developed RFA system. Also the results for profile data such as field size, central axis deviation, penumbra, flatness and symmetry calculated according to various protocols can be obtained for both photon and electron beams. The result of PDDs for photon beams were compared with BJR25 supplement values and the profile data were compared with TG 40 recommendation. The results were in agreement with standard protocols.

  16. Three-dimensional wave-induced current model equations and radiation stresses

    NASA Astrophysics Data System (ADS)

    Xia, Hua-yong

    2017-08-01

    After the approach by Mellor (2003, 2008), the present paper reports on a repeated effort to derive the equations for three-dimensional wave-induced current. Via the vertical momentum equation and a proper coordinate transformation, the phase-averaged wave dynamic pressure is well treated, and a continuous and depth-dependent radiation stress tensor, rather than the controversial delta Dirac function at the surface shown in Mellor (2008), is provided. Besides, a phase-averaged vertical momentum flux over a sloping bottom is introduced. All the inconsistencies in Mellor (2003, 2008), pointed out by Ardhuin et al. (2008) and Bennis and Ardhuin (2011), are overcome in the presently revised equations. In a test case with a sloping sea bed, as shown in Ardhuin et al. (2008), the wave-driving forces derived in the present equations are in good balance, and no spurious vertical circulation occurs outside the surf zone, indicating that Airy's wave theory and the approach of Mellor (2003, 2008) are applicable for the derivation of the wave-induced current model.

  17. Three-dimensional Čerenkov tomography of energy deposition from ionizing radiation beams

    PubMed Central

    Glaser, Adam K.; Voigt, William H.A.; Davis, Scott C.; Zhang, Rongxiao; Gladstone, David J.; Pogue, Brian W.

    2013-01-01

    Since its discovery during the 1930’s, the Čerenkov effect (light emission from charged particles traveling faster than the local speed of light in a dielectric medium) has been paramount in the development of high-energy physics research. The ability of the emitted light to describe a charged particle’s trajectory, energy, velocity, and mass has allowed scientists to study subatomic particles, detect neutrinos, and explore the properties of interstellar matter. However, all applications of the process to date have focused on identification of particle’s themselves, rather than their effect upon the surroundings through which they travel. Here, we explore a novel application of the Čerenkov effect for the recovery of the spatial distribution of ionizing radiation energy deposition in a medium, and apply it to the issue of dose determination in medical physics. By capturing multiple projection images of the Čerenkov light induced by a medical linear accelerator (LINAC) x-ray photon beam, we demonstrate the successful three-dimensional (3D) tomographic reconstruction of the imparted dose distribution for the first time. PMID:23455248

  18. Feasibility and efficacy of high-dose three-dimensional-conformal radiotherapy in cirrhotic patients with small-size hepatocellular carcinoma non-eligible for curative therapies-mature results of the French Phase II RTF-1 trial

    SciTech Connect

    Mornex, Francoise . E-mail: francoise.mornex@chu-lyon.fr; Girard, Nicolas; Beziat, Christophe; Kubas, Abdul; Khodri, Mustapha; Trepo, Christian; Merle, Philippe

    2006-11-15

    Purpose: Hepatocellular carcinoma (HCC) is a poor prognosis tumor, and only 20% of patients will benefit from curative therapies (surgery, liver transplantation, percutaneous ablation). Although conventional radiotherapy has been traditionally regarded as inefficient and toxic for cirrhotic patients, three-dimensional conformal radiotherapy (3DCRT) has provided promising preliminary data for the treatment of HCC. Methods and Materials: Prospective phase II trial including Child-Pugh A/B cirrhotic patients with small-size HCC (1 nodule {<=}5 cm, or 2 nodules {<=}3 cm) nonsuitable for curative treatments, to assess tolerance and efficacy of high-dose (66 Gy, 2 Gy/fraction) 3DCRT. Results: Twenty-seven patients were enrolled. Among the 25 assessable patients, tumor response was observed for 23 patients (92%), with complete response for 20 patients (80%), and partial response for 3 patients (12%). Stable disease was observed in 2 patients (8%). Grade 4 toxicities occurred in 2 of 11 (22%) Child-Pugh B patients only. Child-Pugh A patients tolerated treatment well, and 3/16 (19%) developed asymptomatic Grade 3 toxicities. Conclusion: High-dose 3DCRT is a noninvasive, well-tolerated modality that is highly suitable for the treatment of small HCCs in cirrhotic patients, with promising results. However, additional trials are needed to optimize this technique and formally compare it with the usual curative approaches.

  19. Radiative Effect of Clouds on Tropospheric Chemistry in a Global Three-Dimensional Chemical Transport Model

    NASA Technical Reports Server (NTRS)

    Liu, Hongyu; Crawford, James H.; Pierce, Robert B.; Norris, Peter; Platnick, Steven E.; Chen, Gao; Logan, Jennifer A.; Yantosca, Robert M.; Evans, Mat J.; Kittaka, Chieko; hide

    2006-01-01

    Clouds exert an important influence on tropospheric photochemistry through modification of solar radiation that determines photolysis frequencies (J-values). We assess the radiative effect of clouds on photolysis frequencies and key oxidants in the troposphere with a global three-dimensional (3-D) chemical transport model (GEOS-CHEM) driven by assimilated meteorological observations from the Goddard Earth Observing System data assimilation system (GEOS DAS) at the NASA Global Modeling and Assimilation Office (GMAO). We focus on the year of 2001 with the GEOS-3 meteorological observations. Photolysis frequencies are calculated using the Fast-J radiative transfer algorithm. The GEOS-3 global cloud optical depth and cloud fraction are evaluated and generally consistent with the satellite retrieval products from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the International Satellite Cloud Climatology Project (ISCCP). Results using the linear assumption, which assumes linear scaling of cloud optical depth with cloud fraction in a grid box, show global mean OH concentrations generally increase by less than 6% because of the radiative effect of clouds. The OH distribution shows much larger changes (with maximum decrease of approx.20% near the surface), reflecting the opposite effects of enhanced (weakened) photochemistry above (below) clouds. The global mean photolysis frequencies for J[O1D] and J[NO2] in the troposphere change by less than 5% because of clouds; global mean O3 concentrations in the troposphere increase by less than 5%. This study shows tropical upper tropospheric O3 to be less sensitive to the radiative effect of clouds than previously reported (approx.5% versus approx.20-30%). These results emphasize that the dominant effect of clouds is to influence the vertical redistribution of the intensity of photochemical activity while global average effects remain modest, again contrasting with previous studies. Differing vertical distributions

  20. Radiative Effect of Clouds on Tropospheric Chemistry in a Global Three-Dimensional Chemical Transport Model

    NASA Technical Reports Server (NTRS)

    Liu, Hongyu; Crawford, James H.; Pierce, Robert B.; Norris, Peter; Platnick, Steven E.; Chen, Gao; Logan, Jennifer A.; Yantosca, Robert M.; Evans, Mat J.; Kittaka, Chieko; Feng, Yan; Tie, Xuexi

    2006-01-01

    Clouds exert an important influence on tropospheric photochemistry through modification of solar radiation that determines photolysis frequencies (J-values). We assess the radiative effect of clouds on photolysis frequencies and key oxidants in the troposphere with a global three-dimensional (3-D) chemical transport model (GEOS-CHEM) driven by assimilated meteorological observations from the Goddard Earth Observing System data assimilation system (GEOS DAS) at the NASA Global Modeling and Assimilation Office (GMAO). We focus on the year of 2001 with the GEOS-3 meteorological observations. Photolysis frequencies are calculated using the Fast-J radiative transfer algorithm. The GEOS-3 global cloud optical depth and cloud fraction are evaluated and generally consistent with the satellite retrieval products from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the International Satellite Cloud Climatology Project (ISCCP). Results using the linear assumption, which assumes linear scaling of cloud optical depth with cloud fraction in a grid box, show global mean OH concentrations generally increase by less than 6% because of the radiative effect of clouds. The OH distribution shows much larger changes (with maximum decrease of approx.20% near the surface), reflecting the opposite effects of enhanced (weakened) photochemistry above (below) clouds. The global mean photolysis frequencies for J[O1D] and J[NO2] in the troposphere change by less than 5% because of clouds; global mean O3 concentrations in the troposphere increase by less than 5%. This study shows tropical upper tropospheric O3 to be less sensitive to the radiative effect of clouds than previously reported (approx.5% versus approx.20-30%). These results emphasize that the dominant effect of clouds is to influence the vertical redistribution of the intensity of photochemical activity while global average effects remain modest, again contrasting with previous studies. Differing vertical distributions

  1. Three-dimensional conformal reirradiation for locoregionally recurrent lung cancer previously treated with radiation therapy.

    PubMed

    Huh, Gil Ja; Jang, Seong Soon; Park, Suk Young; Seo, Jae Hyuk; Cho, Eun Youn; Park, Ji Chan; Yang, Young Jun

    2014-07-01

    To evaluate the efficacy and toxicity of reirradiation using three-dimensional conformal radiotherapy (3D-CRT) in symptomatic patients with locoregionally recurrent lung cancer. Between 2005 and 2012, 15 patients with locoregionally recurrent lung cancer were retreated with 3D-CRT after previously receiving thoracic radiotherapy. The median interval between the initial irradiation and reirradiation was 12 months (range, five to 41 months). The median initial radiotherapy dose was 63 Gy (range, 45-70 Gy), and reirradiation doses ranged from 25.2 to 45.2 Gy (median, 36 Gy), with daily fractions of 1.8-4 Gy (median, 2 Gy). After reirradiation, 80% of the patients experienced resolved or diminished symptoms for one or more of their symptoms, with an 83% improvement in a total of 24 symptoms. The overall tumor response rate to reirradiation was 46.7%, with progressive disease occurring in only one patient. The median overall survival (OS) time was 11 months (range, one to 27 months), and the one-year OS rate was 47%. The progression-free survival time ranged from one to 10 months (median, five months). In univariate analysis, the use of combined chemotherapy and a higher reirradiation dose showed a trend toward improved survival after reirradiation. Treatment-induced toxicity included grade 2 radiation pneumonitis in only one patient, and there were no other complications, such as radiation esophagitis or myelopathy. Reirradiation using 3D-CRT with moderate doses for locoregionally recurrent lung cancer can provide palliative benefits without severe complications to the majority of selected patients with symptoms as a result of a regrowing tumor.

  2. Using Synchrotron Radiation Microtomography to Investigate Multi-scale Three-dimensional Microelectronic Packages.

    PubMed

    Carlton, Holly D; Elmer, John W; Li, Yan; Pacheco, Mario; Goyal, Deepak; Parkinson, Dilworth Y; MacDowell, Alastair A

    2016-04-13

    Synchrotron radiation micro-tomography (SRµT) is a non-destructive three-dimensional (3D) imaging technique that offers high flux for fast data acquisition times with high spatial resolution. In the electronics industry there is serious interest in performing failure analysis on 3D microelectronic packages, many which contain multiple levels of high-density interconnections. Often in tomography there is a trade-off between image resolution and the volume of a sample that can be imaged. This inverse relationship limits the usefulness of conventional computed tomography (CT) systems since a microelectronic package is often large in cross sectional area 100-3,600 mm(2), but has important features on the micron scale. The micro-tomography beamline at the Advanced Light Source (ALS), in Berkeley, CA USA, has a setup which is adaptable and can be tailored to a sample's properties, i.e., density, thickness, etc., with a maximum allowable cross-section of 36 x 36 mm. This setup also has the option of being either monochromatic in the energy range ~7-43 keV or operating with maximum flux in white light mode using a polychromatic beam. Presented here are details of the experimental steps taken to image an entire 16 x 16 mm system within a package, in order to obtain 3D images of the system with a spatial resolution of 8.7 µm all within a scan time of less than 3 min. Also shown are results from packages scanned in different orientations and a sectioned package for higher resolution imaging. In contrast a conventional CT system would take hours to record data with potentially poorer resolution. Indeed, the ratio of field-of-view to throughput time is much higher when using the synchrotron radiation tomography setup. The description below of the experimental setup can be implemented and adapted for use with many other multi-materials.

  3. Cell Type-dependent Gene Transcription Profile in Three Dimensional Human Skin Tissue Model Exposed to Low Doses of Ionizing Radiation: Implications for Medical Exposures

    SciTech Connect

    Freiin von Neubeck, Claere H.; Shankaran, Harish; Karin, Norman J.; Kauer, Paula M.; Chrisler, William B.; Wang, Xihai; Robinson, Robert J.; Waters, Katrina M.; Tilton, Susan C.; Sowa, Marianne B.

    2012-04-17

    The concern over possible health risks from exposures to low doses of ionizing radiation has been driven largely by the increase in medical exposures, the routine implementation of X-ray backscatter devices for airport security screening, and, most recently, the nuclear incident in Japan. Due to a paucity of direct epidemiological data at very low doses, cancer risk must be estimated from high dose exposure scenarios. However, there is increasing evidence that low and high dose exposures result in different signaling events and may have different mechanisms of cancer induction. We have examined the radiation induced temporal response of an in vitro three dimensional (3D) human skin tissue model using microarray-based transcriptional profiling. Our data shows that exposure to 100 mGy of X-rays is sufficient to affect gene transcription. Cell type specific analysis showed significant changes in gene expression with the levels of > 1400 genes altered in the dermis and > 400 genes regulated in the epidermis. The two cell types rarely exhibited overlapping responses at the mRNA level. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) measurements validated the microarray data in both regulation direction and value. Key pathways identified relate to cell cycle regulation, immune responses, hypoxia, reactive oxygen signaling, and DNA damage repair. We discuss in particular the role of proliferation and emphasizing how the disregulation of cellular signaling in normal tissue may impact progression towards radiation induced secondary diseases.

  4. Genomic characterization of a three-dimensional skin model following exposure to ionizing radiation.

    PubMed

    Yunis, Reem; Albrecht, Huguette; Kalanetra, Karen M; Wu, Shiquan; Rocke, David M

    2012-11-01

    This study aimed at characterizing the genomic response to low versus moderate doses of ionizing radiation (LDIR versus MDIR) in a three-dimensional (3D) skin model, which exhibits a closer tissue complexity to human skin than monolayer cell cultures. EpiDermFT skin plugs were exposed to 0, 0.1 and 1 Gy doses of X-rays and harvested at 5 min, 3, 8 and 24 h post-irradiation (post-IR). RNA was interrogated for global gene expression alteration. Our results show that MDIR modulated a larger number of genes over the course of 24 h compared to LDIR. However, immediately and throughout the first 3h post-IR, LDIR modulated a larger number of genes than MDIR, mostly associated with cell-cell signaling and survival promotion. Significant modulation of pathways was detected only at 3 h post-IR in MDIR with induction of genes promoting apoptosis. Collectively, the data show different dynamics in the response to LDIR versus MDIR, especially in cell-cycle distribution. LDIR-exposed tissues showed signs of attempted cell-cycle re-entry as early as 3 h post-IR, but were arrested beyond 8 h at the G1/S checkpoint. At 24 h, cells appeared to accumulate at the G2/M checkpoint. MDIR-exposed tissues did not exhibit a prolonged G1/S arrest but rather a prolonged G2/M arrest, which was sustained at least up to 24 h. By 24 h cells exhibited signs of recovery in both LDIR- and MDIR-exposed tissues. In summary, the most pronounced difference in the initial cellular response to LDIR versus MDIR is the promotion of protection and survival in LDIR versus the promotion of apoptosis in MDIR.

  5. INVESTIGATING THE RELIABILITY OF CORONAL EMISSION MEASURE DISTRIBUTION DIAGNOSTICS USING THREE-DIMENSIONAL RADIATIVE MAGNETOHYDRODYNAMIC SIMULATIONS

    SciTech Connect

    Testa, Paola; De Pontieu, Bart; Martinez-Sykora, Juan; Hansteen, Viggo; Carlsson, Mats

    2012-10-10

    Determining the temperature distribution of coronal plasmas can provide stringent constraints on coronal heating. Current observations with the Extreme ultraviolet Imaging Spectrograph (EIS) on board Hinode and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory provide diagnostics of the emission measure distribution (EMD) of the coronal plasma. Here we test the reliability of temperature diagnostics using three-dimensional radiative MHD simulations. We produce synthetic observables from the models and apply the Monte Carlo Markov chain EMD diagnostic. By comparing the derived EMDs with the 'true' distributions from the model, we assess the limitations of the diagnostics as a function of the plasma parameters and the signal-to-noise ratio of the data. We find that EMDs derived from EIS synthetic data reproduce some general characteristics of the true distributions, but usually show differences from the true EMDs that are much larger than the estimated uncertainties suggest, especially when structures with significantly different density overlap along the line of sight. When using AIA synthetic data the derived EMDs reproduce the true EMDs much less accurately, especially for broad EMDs. The differences between the two instruments are due to the: (1) smaller number of constraints provided by AIA data and (2) broad temperature response function of the AIA channels which provide looser constraints to the temperature distribution. Our results suggest that EMDs derived from current observatories may often show significant discrepancies from the true EMDs, rendering their interpretation fraught with uncertainty. These inherent limitations to the method should be carefully considered when using these distributions to constrain coronal heating.

  6. Variation of clinical target volume definition in three-dimensional conformal radiation therapy for prostate cancer.

    PubMed

    Valicenti, R K; Sweet, J W; Hauck, W W; Hudes, R S; Lee, T; Dicker, A P; Waterman, F M; Anne, P R; Corn, B W; Galvin, J M

    1999-07-01

    Currently, three-dimensional conformal radiation therapy (3D-CRT) planning relies on the interpretation of computed tomography (CT) axial images for defining the clinical target volume (CTV). This study investigates the variation among multiple observers to define the CTV used in 3D-CRT for prostate cancer. Seven observers independently delineated the CTVs (prostate +/- seminal vesicles [SV]) from the CT simulation data of 10 prostate cancer patients undergoing 3D-CRT. Six patients underwent CT simulation without the use of contrast material and serve as a control group. The other 4 had urethral and bladder opacification with contrast medium. To determine interobserver variation, we evaluated the derived volume, the maximum dimensions, and the isocenter for each examination of CTV. We assessed the reliability in the CTVs among the observers by correlating the variation for each class of measurements. This was estimated by intraclass correlation coefficient (ICC), with 1.00 defining absolute correlation. For the prostate volumes, the ICC was 0.80 (95% confidence interval [CI]: 0.56-0.96). This changed to 0.92 (95% CI: 0.75-0.99) with the use of contrast material. Similarly, the maximal prostatic dimensions were reliable and improved. There was poor agreement in defining the SV. For this structure, the ICC never exceeded 0.28. The reliability of the isocenter was excellent, with the ICC exceeding 0.83 and 0.90 for the prostate +/- SV, respectively. In 3D-CRT for prostate cancer, there was excellent agreement among multiple observers to define the prostate target volume but poor agreement to define the SV. The use of urethral and bladder contrast improved the reliability of localizing the prostate. For all CTVs, the isocenter was very reliable and should be used to compare the variation in 3D dosimetry among multiple observers.

  7. Carcinoma of the anal canal: Intensity modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3DCRT)

    SciTech Connect

    Sale, Charlotte; Moloney, Phillip; Mathlum, Maitham

    2013-12-15

    Patients with anal canal carcinoma treated with standard conformal radiotherapy frequently experience severe acute and late toxicity reactions to the treatment area. Roohipour et al. (Dis Colon Rectum 2008; 51: 147–53) stated a patient's tolerance of chemoradiation to be an important prediction of treatment success. A new intensity modulated radiation therapy (IMRT) technique for anal carcinoma cases has been developed at the Andrew Love Cancer Centre aimed at reducing radiation to surrounding healthy tissue. A same-subject repeated measures design was used for this study, where five anal carcinoma cases at the Andrew Love Cancer Centre were selected. Conformal and IMRT plans were generated and dosimetric evaluations were performed. Each plan was prescribed a total of 54 Gray (Gy) over a course of 30 fractions to the primary site. The IMRT plans resulted in improved dosimetry to the planning target volume (PTV) and reduction in radiation to the critical structures (bladder, external genitalia and femoral heads). Statistically there was no difference between the IMRT and conformal plans in the dose to the small and large bowel; however, the bowel IMRT dose–volume histogram (DVH) doses were consistently lower. The IMRT plans were superior to the conformal plans with improved dose conformity and reduced radiation to the surrounding healthy tissue. Anecdotally it was found that patients tolerated the IMRT treatment better than the three-dimensional (3D) conformal radiation therapy. This study describes and compares the planning techniques.

  8. Carcinoma of the anal canal: Intensity modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3DCRT)

    PubMed Central

    Sale, Charlotte; Moloney, Phillip; Mathlum, Maitham

    2013-01-01

    Introduction Patients with anal canal carcinoma treated with standard conformal radiotherapy frequently experience severe acute and late toxicity reactions to the treatment area. Roohipour et al. (Dis Colon Rectum 2008; 51: 147–53) stated a patient's tolerance of chemoradiation to be an important prediction of treatment success. A new intensity modulated radiation therapy (IMRT) technique for anal carcinoma cases has been developed at the Andrew Love Cancer Centre aimed at reducing radiation to surrounding healthy tissue. Methods A same-subject repeated measures design was used for this study, where five anal carcinoma cases at the Andrew Love Cancer Centre were selected. Conformal and IMRT plans were generated and dosimetric evaluations were performed. Each plan was prescribed a total of 54 Gray (Gy) over a course of 30 fractions to the primary site. Results The IMRT plans resulted in improved dosimetry to the planning target volume (PTV) and reduction in radiation to the critical structures (bladder, external genitalia and femoral heads). Statistically there was no difference between the IMRT and conformal plans in the dose to the small and large bowel; however, the bowel IMRT dose–volume histogram (DVH) doses were consistently lower. Conclusion The IMRT plans were superior to the conformal plans with improved dose conformity and reduced radiation to the surrounding healthy tissue. Anecdotally it was found that patients tolerated the IMRT treatment better than the three-dimensional (3D) conformal radiation therapy. This study describes and compares the planning techniques. PMID:26229623

  9. Three-dimensional dosimetry of small megavoltage radiation fields using radiochromic gels and optical CT scanning.

    PubMed

    Babic, Steven; McNiven, Andrea; Battista, Jerry; Jordan, Kevin

    2009-04-21

    The dosimetry of small fields as used in stereotactic radiotherapy, radiosurgery and intensity-modulated radiation therapy can be challenging and inaccurate due to partial volume averaging effects and possible disruption of charged particle equilibrium. Consequently, there exists a need for an integrating, tissue equivalent dosimeter with high spatial resolution to avoid perturbing the radiation beam and artificially broadening the measured beam penumbra. In this work, radiochromic ferrous xylenol-orange (FX) and leuco crystal violet (LCV) micelle gels were used to measure relative dose factors (RDFs), percent depth dose profiles and relative lateral beam profiles of 6 MV x-ray pencil beams of diameter 28.1, 9.8 and 4.9 mm. The pencil beams were produced via stereotactic collimators mounted on a Varian 2100 EX linear accelerator. The gels were read using optical computed tomography (CT). Data sets were compared quantitatively with dosimetric measurements made with radiographic (Kodak EDR2) and radiochromic (GAFChromic EBT) film, respectively. Using a fast cone-beam optical CT scanner (Vista), corrections for diffusion in the FX gel data yielded RDFs that were comparable to those obtained by minimally diffusing LCV gels. Considering EBT film-measured RDF data as reference, cone-beam CT-scanned LCV gel data, corrected for scattered stray light, were found to be in agreement within 0.5% and -0.6% for the 9.8 and 4.9 mm diameter fields, respectively. The validity of the scattered stray light correction was confirmed by general agreement with RDF data obtained from the same LCV gel read out with a laser CT scanner that is less prone to the acceptance of scattered stray light. Percent depth dose profiles and lateral beam profiles were found to agree within experimental error for the FX gel (corrected for diffusion), LCV gel (corrected for scattered stray light), and EBT and EDR2 films. The results from this study reveal that a three-dimensional dosimetry method utilizing

  10. Laser-processed three dimensional graphitic electrodes for diamond radiation detectors

    SciTech Connect

    Caylar, Benoı-carett; Pomorski, Michal; Bergonzo, Philippe

    2013-07-22

    We have used an original approach for diamond detectors where three dimensional buried graphitic electrodes are processed in the bulk of a diamond substrate via laser-induced graphitization. Prototype made of polycrystalline chemical vapor deposition diamond was fabricated using a nanosecond UV laser. Its charge collection efficiency was evaluated using α-particles emitted by a 241-Americium source. An improved charge collection efficiency was measured proving that laser micro-machining of diamond is a valid option for the future fabrication of three dimensional diamond detectors.

  11. Laser-processed three dimensional graphitic electrodes for diamond radiation detectors

    NASA Astrophysics Data System (ADS)

    Caylar, Benoît; Pomorski, Michal; Bergonzo, Philippe

    2013-07-01

    We have used an original approach for diamond detectors where three dimensional buried graphitic electrodes are processed in the bulk of a diamond substrate via laser-induced graphitization. Prototype made of polycrystalline chemical vapor deposition diamond was fabricated using a nanosecond UV laser. Its charge collection efficiency was evaluated using α-particles emitted by a 241-Americium source. An improved charge collection efficiency was measured proving that laser micro-machining of diamond is a valid option for the future fabrication of three dimensional diamond detectors.

  12. Gene expression profiling in undifferentiated thyroid carcinoma induced by high-dose radiation

    PubMed Central

    Bang, Hyun Soon; Choi, Moo Hyun; Kim, Cha Soon; Choi, Seung Jin

    2016-01-01

    Published gene expression studies for radiation-induced thyroid carcinogenesis have used various methodologies. In this study, we identified differential gene expression in a human thyroid epithelial cell line after exposure to high-dose γ-radiation. HTori-3 cells were exposed to 5 or 10 Gy of ionizing radiation using two dose rates (high-dose rate: 4.68 Gy/min, and low-dose rate: 40 mGy/h) and then implanted into the backs of BALB/c nude mice after 4 (10 Gy) or 5 weeks (5 Gy). Decreases in cell viability, increases in giant cell frequency, anchorage-independent growth in vitro, and tumorigenicity in vivo were observed. Particularly, the cells irradiated with 5 Gy at the high-dose rate or 10 Gy at the low-dose rate demonstrated more prominent tumorigenicity. Gene expression profiling was analyzed via microarray. Numerous genes that were significantly altered by a fold-change of >50% following irradiation were identified in each group. Gene expression analysis identified six commonly misregulated genes, including CRYAB, IL-18, ZNF845, CYP24A1, OR4N4 and VN1R4, at all doses. These genes involve apoptosis, the immune response, regulation of transcription, and receptor signaling pathways. Overall, the altered genes in high-dose rate (HDR) 5 Gy and low-dose rate (LDR) 10 Gy were more than those of LDR 5 Gy and HDR 10 Gy. Thus, we investigated genes associated with aggressive tumor development using the two dosage treatments. In this study, the identified gene expression profiles reflect the molecular response following high doses of external radiation exposure and may provide helpful information about radiation-induced thyroid tumors in the high-dose range. PMID:27006382

  13. Use of three-dimensional mapping in young patients decreases radiation exposure even without a goal of zero fluoroscopy.

    PubMed

    Beach, Cheyenne; Beerman, Lee; Mazzocco, Sharon; Brooks, Maria M; Arora, Gaurav

    2016-10-01

    At present, three-dimensional mapping is often used during cardiac ablations with an explicit goal of decreasing radiation exposure; three-dimensional mapping was introduced in our institution in 2007, but not specifically to decrease fluoroscopy time. We document fluoroscopy use and catheterisation times in this setting. Data were obtained retrospectively from patients who underwent ablation for atrioventricular nodal re-entrant tachycardia from January, 2004 to December, 2011. A total of 93 patients were included in the study. Among them, 18 patients who underwent radiofrequency ablation without three-dimensional mapping were included in Group 1, 13 patients who underwent cryoablation without three-dimensional mapping were included in Group 2, and 62 patients who underwent cryoablation with three-dimensional mapping were included in Group 3. Mean fluoroscopy times differed significantly (34.3, 23.4, and 20.3 minutes, p<0.001) when all the groups were compared. Group 3 had a shorter average fluoroscopy time that did not reach significance when compared directly with Group 2 (p=0.29). An unadjusted linear regression model showed a progressive decrease in fluoroscopy time (p=0.002). Mean total catheterisation times differed significantly (180, 211, and 210 minutes, p=0.02) and were related to increased ablation times inherent to cryoablation techniques. Acute success was achieved in 89, 100, and 97% of patients (p=0.25), and chronic success was achieved in 80, 92, and 93% of patients (p=0.38). Complication rates were similar (17, 23, and 7%, p=0.14). In conclusion, three-dimensional mapping systems decrease fluoroscopy times even without an explicit goal of zero fluoroscopy. Efficacy and safety of the procedure have not changed.

  14. Statistics Analysis of the Uncertainties in Cloud Optical Depth Retrievals Caused by Three-Dimensional Radiative Effects

    NASA Technical Reports Server (NTRS)

    Varnai, Tamas; Marshak, Alexander

    2000-01-01

    This paper presents a simple approach to estimate the uncertainties that arise in satellite retrievals of cloud optical depth when the retrievals use one-dimensional radiative transfer theory for heterogeneous clouds that have variations in all three dimensions. For the first time, preliminary error bounds are set to estimate the uncertainty of cloud optical depth retrievals. These estimates can help us better understand the nature of uncertainties that three-dimensional effects can introduce into retrievals of this important product of the MODIS instrument. The probability distribution of resulting retrieval errors is examined through theoretical simulations of shortwave cloud reflection for a wide variety of cloud fields. The results are used to illustrate how retrieval uncertainties change with observable and known parameters, such as solar elevation or cloud brightness. Furthermore, the results indicate that a tendency observed in an earlier study, clouds appearing thicker for oblique sun, is indeed caused by three-dimensional radiative effects.

  15. Spatially resolved measurement of high doses in microbeam radiation therapy using samarium doped fluorophosphate glasses

    SciTech Connect

    Okada, Go; Morrell, Brian; Koughia, Cyril; Kasap, Safa; Edgar, Andy; Varoy, Chris; Belev, George; Wysokinski, Tomasz; Chapman, Dean

    2011-09-19

    The measurement of spatially resolved high doses in microbeam radiation therapy has always been a challenging task, where a combination of high dose response and high spatial resolution (microns) is required for synchrotron radiation peaked around 50 keV. The x-ray induced Sm{sup 3+}{yields} Sm{sup 2+} valence conversion in Sm{sup 3+} doped fluorophosphates glasses has been tested for use in x-ray dosimetry for microbeam radiation therapy. The conversion efficiency depends almost linearly on the dose of irradiation up to {approx}5 Gy and saturates at doses exceeding {approx}80 Gy. The conversion shows strong correlation with x-ray induced absorbance of the glass which is related to the formation of phosphorus-oxygen hole centers. When irradiated through a microslit collimator, a good spatial resolution and high ''peak-to-valley'' contrast have been observed by means of confocal photoluminescence microscopy.

  16. Nanotube-based three-dimensional albumin composite obtained using continuous laser radiation

    SciTech Connect

    Ageeva, S. A.; Bobrinetskii, I. I.; Nevolin, V. K. Podgaetskii, V. M.; Selishchev, S. V.; Simunin, M. M.; Konov, V. I.; Savranskii, V. V.

    2009-12-15

    The possibility of developing three-dimensional nanostructures for damaged bone and tissue restoration, including treatment of human congenital malformation is considered. Four types of multiwalled and single-walled carbon nanotubes fabricated by chemical vapor deposition via disproportionation on Fe clusters and thermal cathode sputtering in an inert gas were studied. The nanomaterial's topography was studied by atomic-force microscopy. The possibility of using 3D nanocomposites as a biosolder for laser biowelding of cartilaginous tissue was shown. The compatibility of biological tissues with a nanocomposite material in vivo introduced under the perichondrium of ear cartilage of a rabbit was validated.

  17. A finite element-boundary integral method for scattering and radiation by two- and three-dimensional structures

    NASA Technical Reports Server (NTRS)

    Jin, Jian-Ming; Volakis, John L.; Collins, Jeffery D.

    1991-01-01

    A review of a hybrid finite element-boundary integral formulation for scattering and radiation by two- and three-dimensional composite structures is presented. In contrast to other hybrid techniques involving the finite element method, the proposed one is in principle exact and can be implemented using a low O(N) storage. This is of particular importance for large scale applications and is a characteristic of the boundary chosen to terminate the finite element mesh, usually as close to the structure as possible. A certain class of these boundaries lead to convolutional boundary integrals which can be evaluated via the fast Fourier transform (FFT) without a need to generate a matrix; thus, retaining the O(N) storage requirement. The paper begins with a general description of the method. A number of two- and three-dimensional applications are then given, including numerical computations which demonstrate the method's accuracy, efficiency, and capability.

  18. Integral Dose and Radiation-Induced Secondary Malignancies: Comparison between Stereotactic Body Radiation Therapy and Three-Dimensional Conformal Radiotherapy

    PubMed Central

    D’Arienzo, Marco; Masciullo, Stefano G.; de Sanctis, Vitaliana; Osti, Mattia F.; Chiacchiararelli, Laura; Enrici, Riccardo M.

    2012-01-01

    The aim of the present paper is to compare the integral dose received by non-tumor tissue (NTID) in stereotactic body radiation therapy (SBRT) with modified LINAC with that received by three-dimensional conformal radiotherapy (3D-CRT), estimating possible correlations between NTID and radiation-induced secondary malignancy risk. Eight patients with intrathoracic lesions were treated with SBRT, 23 Gy × 1 fraction. All patients were then replanned for 3D-CRT, maintaining the same target coverage and applying a dose scheme of 2 Gy × 32 fractions. The dose equivalence between the different treatment modalities was achieved assuming α/β = 10Gy for tumor tissue and imposing the same biological effective dose (BED) on the target (BED = 76Gy10). Total NTIDs for both techniques was calculated considering α/β = 3Gy for healthy tissue. Excess absolute cancer risk (EAR) was calculated for various organs using a mechanistic model that includes fractionation effects. A paired two-tailed Student t-test was performed to determine statistically significant differences between the data (p ≤ 0.05). Our study indicates that despite the fact that for all patients integral dose is higher for SBRT treatments than 3D-CRT (p = 0.002), secondary cancer risk associated to SBRT patients is significantly smaller than that calculated for 3D-CRT (p = 0.001). This suggests that integral dose is not a good estimator for quantifying cancer induction. Indeed, for the model and parameters used, hypofractionated radiotherapy has the potential for secondary cancer reduction. The development of reliable secondary cancer risk models seems to be a key issue in fractionated radiotherapy. Further assessments of integral doses received with 3D-CRT and other special techniques are also strongly encouraged. PMID:23202843

  19. Integral dose and radiation-induced secondary malignancies: comparison between stereotactic body radiation therapy and three-dimensional conformal radiotherapy.

    PubMed

    D'Arienzo, Marco; Masciullo, Stefano G; de Sanctis, Vitaliana; Osti, Mattia F; Chiacchiararelli, Laura; Enrici, Riccardo M

    2012-11-19

    The aim of the present paper is to compare the integral dose received by non-tumor tissue (NTID) in stereotactic body radiation therapy (SBRT) with modified LINAC with that received by three-dimensional conformal radiotherapy (3D-CRT), estimating possible correlations between NTID and radiation-induced secondary malignancy risk. Eight patients with intrathoracic lesions were treated with SBRT, 23 Gy × 1 fraction. All patients were then replanned for 3D-CRT, maintaining the same target coverage and applying a dose scheme of 2 Gy × 32 fractions. The dose equivalence between the different treatment modalities was achieved assuming α/β = 10 Gy for tumor tissue and imposing the same biological effective dose (BED) on the target (BED = 76 Gy(10)). Total NTIDs for both techniques was calculated considering α/β = 3 Gy for healthy tissue. Excess absolute cancer risk (EAR) was calculated for various organs using a mechanistic model that includes fractionation effects. A paired two-tailed Student t-test was performed to determine statistically significant differences between the data (p ≤ 0.05). Our study indicates that despite the fact that for all patients integral dose is higher for SBRT treatments than 3D-CRT (p = 0.002), secondary cancer risk associated to SBRT patients is significantly smaller than that calculated for 3D-CRT (p = 0.001). This suggests that integral dose is not a good estimator for quantifying cancer induction. Indeed, for the model and parameters used, hypofractionated radiotherapy has the potential for secondary cancer reduction. The development of reliable secondary cancer risk models seems to be a key issue in fractionated radiotherapy. Further assessments of integral doses received with 3D-CRT and other special techniques are also strongly encouraged.

  20. Micro-fabrication by laser radiation forces: a direct route to reversible free-standing three-dimensional structures.

    PubMed

    Athanasekos, Loukas; Vasileiadis, Miltiadis; Mantzaridis, Christos; Karoutsos, Vagelis C; Koutselas, Ioannis; Pispas, Stergios; Vainos, Nikolaos A

    2012-10-22

    The origins and first demonstration of structurally stable solids formed by use of radiation forces are presented. By experimentally proving that radiation forces can indeed produce stable solid material forms, a novel method enabling two- and three-dimensional (2d and 3d) microfabrication is introduced: An optical, non-contact single-step physical operation, reversible with respect to materials nature, based on the sole use of radiation forces. The present innovation is elucidated by the formation of polyisoprene and polybutadiene micro-solids, as well as plasmonic and fluorescent hybrids, respectively comprising Au nanoparticles and CdS quantum dots, together with novel concepts of polymeric fiber-drawing by radiation forces.

  1. Three Dimensional Radiation Transport Analyses in Pwr with Tort and Mcnp

    NASA Astrophysics Data System (ADS)

    Fukuya, Koji; Nakata, Hayato; Kimura, Itsuro; Kitagawa, Hideo; Ohmura, Masaki; Ito, Taku; Shin, Kazuo

    2003-06-01

    Three dimensional (3D) neutron and gamma calculations for structural materials inside the reactor vessel in a commercial PWR were performed using the 3D transport code TORT and the Monte Carlo code MCNP to assess the accuracy of calculations using these codes and libraries. Comparisons with two dimensional DORT calculations with various libraries and surveillance dosimetry measurements indicated that TORT and MCNP calculations give similar agreements with surveillance measurements to DORT calculations. Influences of the cross section data, ENDF/B-IV, ENDF/B-VI and JENDL3.2 on attenuation of the fast flux and dpa rate in the reactor vessel, relative contributions of gamma-rays and thermal neutrons to dpa were discussed.

  2. Radiation bronchitis and stenosis secondary to high dose rate endobronchial irradiation

    SciTech Connect

    Speiser, B.L. ); Spratling, L.

    1993-03-15

    The purpose of the study was to describe a new clinical entity observed in follow-up bronchoscopies in patients who were treated with high dose rate and medium dose rate remote afterloading brachytherapy of the tracheobronchial tree. Patients were treated by protocol with medium dose rate, 47 patients receiving 1000 cGy at a 5 mm depth times three fractions, high dose rate 144 patients receiving 1000 cGy at a 10 mm depth for three fractions and high dose rate 151 patients receiving cGy at a 10 mm depth for three fractions followed by bronchoscopy. Incidence of this entity was 9% for the first group, 12% for the second, and 13% for the third group. Reactions were grade 1 consisting of mild inflammatory response with a partial whitish circumferential membrane in an asymptomatic patient; grade 2, thicker complete white circumferential membrane with cough and/or obstructive problems requiring intervention; grade 3, severe inflammatory response with marked membranous exudate and mild fibrotic reaction; and grade 4 a predominant fibrotic reaction with progressive stenosis. Variables associated with a slightly increased incidence of radiation bronchitis and stenosis included: large cell carcinoma histology, curative intent, prior laser photoresection, and/or concurrent external radiation. Survival was the strongest predictor of the reaction. Radiation bronchitis and stenosis is a new clinical entity that must be identified in bronchial brachytherapy patients and treated appropriately. 23 refs., 3 figs., 7 tabs.

  3. Electron beam requirements for a three-dimensional Smith-Purcell backward-wave oscillator for intense terahertz radiation.

    SciTech Connect

    Kim, K.-J.; Kumar, V.; Accelerator Systems Division; Raja Ramanna Center for Advanced Tech.

    2007-08-01

    A Smith-Purcell device can operate as a backward-wave oscillator for intense, narrow-bandwidth, continuous wave radiation at terahertz wavelengths. We determine the requirements on electron beam current and emittance for the system to oscillate based on a three-dimensional extension of our previous two-dimensional analysis. It is found that specially designed electron beams are required with a current that exceeds a certain threshold value and a flat transverse profile that allows the beam to travel very close to the grating surface. Two methods for producing electron beams with the required characteristics are discussed.

  4. Comparison of low and high dose ionising radiation using topological analysis of gene coexpression networks.

    PubMed

    Ray, Monika; Yunis, Reem; Chen, Xiucui; Rocke, David M

    2012-05-17

    The growing use of imaging procedures in medicine has raised concerns about exposure to low-dose ionising radiation (LDIR). While the disastrous effects of high dose ionising radiation (HDIR) is well documented, the detrimental effects of LDIR is not well understood and has been a topic of much debate. Since little is known about the effects of LDIR, various kinds of wet-lab and computational analyses are required to advance knowledge in this domain. In this paper we carry out an "upside-down pyramid" form of systems biology analysis of microarray data. We characterised the global genomic response following 10 cGy (low dose) and 100 cGy (high dose) doses of X-ray ionising radiation at four time points by analysing the topology of gene coexpression networks. This study includes a rich experimental design and state-of-the-art computational systems biology methods of analysis to study the differences in the transcriptional response of skin cells exposed to low and high doses of radiation. Using this method we found important genes that have been linked to immune response, cell survival and apoptosis. Furthermore, we also were able to identify genes such as BRCA1, ABCA1, TNFRSF1B, MLLT11 that have been associated with various types of cancers. We were also able to detect many genes known to be associated with various medical conditions. Our method of applying network topological differences can aid in identifying the differences among similar (eg: radiation effect) yet very different biological conditions (eg: different dose and time) to generate testable hypotheses. This is the first study where a network level analysis was performed across two different radiation doses at various time points, thereby illustrating changes in the cellular response over time.

  5. Comparison of low and high dose ionising radiation using topological analysis of gene coexpression networks

    PubMed Central

    2012-01-01

    Background The growing use of imaging procedures in medicine has raised concerns about exposure to low-dose ionising radiation (LDIR). While the disastrous effects of high dose ionising radiation (HDIR) is well documented, the detrimental effects of LDIR is not well understood and has been a topic of much debate. Since little is known about the effects of LDIR, various kinds of wet-lab and computational analyses are required to advance knowledge in this domain. In this paper we carry out an “upside-down pyramid” form of systems biology analysis of microarray data. We characterised the global genomic response following 10 cGy (low dose) and 100 cGy (high dose) doses of X-ray ionising radiation at four time points by analysing the topology of gene coexpression networks. This study includes a rich experimental design and state-of-the-art computational systems biology methods of analysis to study the differences in the transcriptional response of skin cells exposed to low and high doses of radiation. Results Using this method we found important genes that have been linked to immune response, cell survival and apoptosis. Furthermore, we also were able to identify genes such as BRCA1, ABCA1, TNFRSF1B, MLLT11 that have been associated with various types of cancers. We were also able to detect many genes known to be associated with various medical conditions. Conclusions Our method of applying network topological differences can aid in identifying the differences among similar (eg: radiation effect) yet very different biological conditions (eg: different dose and time) to generate testable hypotheses. This is the first study where a network level analysis was performed across two different radiation doses at various time points, thereby illustrating changes in the cellular response over time. PMID:22594378

  6. Three-dimensional conformal intensity-modulated radiation therapy of left femur foci does not damage the sciatic nerve

    PubMed Central

    Xu, Wanlong; Zhao, Xibin; Wang, Qing; Sun, Jungang; Xu, Jiangbo; Zhou, Wenzheng; Wang, Hao; Yan, Shigui; Yuan, Hong

    2014-01-01

    During radiotherapy to kill femoral hydatid tapeworms, the sciatic nerve surrounding the focus can be easily damaged by the treatment. Thus, it is very important to evaluate the effects of radiotherapy on the surrounding nervous tissue. In the present study, we used three-dimensional, conformal, intensity-modulated radiation therapy to treat bilateral femoral hydatid disease in Meriones meridiani. The focus of the hydatid disease on the left femur was subjected to radiotherapy (40 Gy) for 14 days, and the right femur received sham irradiation. Hematoxylin-eosin staining, electron microscopy, and terminal deoxynucleotidyl transferase-dUTP nick end labeling assays on the left femurs showed that the left sciatic nerve cell structure was normal, with no obvious apoptosis after radiation. Trypan blue staining demonstrated that the overall protoscolex structure in bone parasitized with Echinococcus granulosus disappeared in the left femur of the animals after treatment. The mortality of the protoscolex was higher in the left side than in the right side. The succinate dehydrogenase activity in the protoscolex in bone parasitized with Echinococcus granulosus was lower in the left femur than in the right femur. These results suggest that three-dimensional conformal intensity-modulated radiation therapy achieves good therapeutic effects on the secondary bone in hydatid disease in Meriones meridiani without damaging the morphology or function of the sciatic nerve. PMID:25422645

  7. Natural element method for solving radiative transfer with or without conduction in three-dimensional complex geometries

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Ma, Yu; Yi, Hong-Liang; Tan, He-Ping

    2013-11-01

    A meshless method called as the natural element method (NEM) is developed for solving radiative heat transfer problem in 3D complex enclosures filled with an absorbing, emitting and scattering medium. The boundary surfaces are supposed to be opaque, diffuse as well as gray. The shape functions used in NEM are constructed by the natural neighbor interpolations, which are strictly interpolant and the essential boundary conditions can be imposed directly. The NEM solutions dealing with the radiative heat transfer with or without conduction are validated by comparison with some cases reported by the literature. Furthermore, the radiative heat transfer in cubic enclosures with or without an inner hollow sphere, cylinder and elliptical cylinder is also examined to demonstrate the applicability of the present method towards various three-dimensional geometries. For pure radiative transfer, both the cases of radiative non-equilibrium and radiative equilibrium are investigated. For combined conduction and radiation heat transfer, effects of various parameters such as the conduction-radiation parameter, the scattering albedo, the extinction coefficient, and the boundary emissivity are analyzed on the temperature distributions.

  8. Three-dimensional radiation dosimetry based on optically-stimulated luminescence

    NASA Astrophysics Data System (ADS)

    Sadel, M.; Høye, E. M.; Skyt, P. S.; Muren, L. P.; Petersen, J. B. B.; Balling, P.

    2017-05-01

    A new approach to three-dimensional (3D) dosimetry based on optically-stimulated luminescence (OSL) is presented. By embedding OSL-active particles into a transparent silicone matrix (PDMS), the well-established dosimetric properties of an OSL material are exploited in a 3D-OSL dosimeter. By investigating prototype dosimeters in standard cuvettes in combination with small test samples for OSL readers, it is shown that a sufficient transparency of the 3D-OSL material can be combined with an OSL response giving an estimated >10.000 detected photons in 1 second per 1mm3 voxel of the dosimeter at a dose of 1 Gy. The dose distribution in the 3D-OSL dosimeters can be directly read out optically without the need for subsequent reconstruction by computational inversion algorithms. The dosimeters carry the advantages known from personal-dosimetry use of OSL: the dose distribution following irradiation can be stored with minimal fading for extended periods of time, and dosimeters are reusable as they can be reset, e.g. by an intense (bleaching) light field.

  9. Dispersion characteristics of three-dimensional dielectric-loaded grating for terahertz Smith-Purcell radiation

    SciTech Connect

    Cao, Miaomiao Li, Ke; Liu, Wenxin Wang, Yong

    2014-02-15

    In this paper, a dielectric-loaded grating for Smith-Purcell device is proposed. The three-dimensional (3D) analytical theory for hot dispersion relation is obtained by using field matched method, which is solved by numerical simulations. The first and second order growth rates for the proposal model are analyzed, which is obtained by expanding hot dispersion equation at the operating point. The results show that the dispersion can be effectively weakened by introducing dielectric-loaded grating, in which the cutoff frequency is affected by the grating thickness. The dispersion curve becomes flatter and shifts towards lower frequency at the optimum grating parameters. The 3D particle-in-cell (PIC) simulation is also performed and the results are in good agreement with theoretical calculations. Comparing the first order growth rate with the second one, it reveals that the discrepancy is small when electron beam parameters are selected with small values. Otherwise, the discrepancy is large and cannot be ignored. To accurately describe the process of beam-wave interaction, the second order growth rate is necessary to apply.

  10. Three-Dimensional Characterization of Cell Clusters Using Synchrotron-Radiation-Based Micro-Computed Tomography

    NASA Astrophysics Data System (ADS)

    Müller, Ert; Riedel, Marco; Thurner, Philipp J.

    2006-04-01

    Micro-computed tomography with the highly intense, monochromatic X rays produced by the synchrotron is a superior method to nondestructively measure the local absorption in three-dimensional space. Because biological tissues and cells consist mainly of water as the surrounding medium, higher absorbing agents have to be incorporated into the structures of interest. Even without X-ray optics such as refractive lens, one can uncover the stain distribution with the spatial resolution of about 1 [mu]m. Incorporating the stain at selected cell compartments, for example, binding to the RNA/DNA, their density distribution becomes quantified. In this communication, we demonstrate that tomograms obtained at the beamlines BW2 and W2 (HASYLAB at DESY, Hamburg, Germany) and 4S (SLS, Villigen, Switzerland) clearly show that the RNA/DNA-stained HEK 293 cell clusters have a core of high density and a peripheral part of lower density, which correlate with results of optical microscopy. The inner part of the clusters is associated with nonvital cells as the result of insufficient oxygen and nutrition supply. This necrotic part is surrounded by (6 ± 1) layers of vital cells.

  11. Three Dimensional Radiation Fields in Free Electron Lasers Using Lienard-Wiechert Fields,

    DTIC Science & Technology

    1981-10-28

    compared to 60 trad for the short pulse. It is possible to think of the resultant radiation as being generated by a long line of phased-array antenas ...cone of angular dimension given approximately by 1/No where No is the number of radiators in the antena . For the FEL, however, No represents the number

  12. Three-dimensional radiative interactions in a polluted broken cloud system

    NASA Astrophysics Data System (ADS)

    Podgorny, I. A.

    2003-07-01

    This paper is a theoretical study of short-wave radiative interactions in a polluted broken cloud scene encountered during the Indian Ocean Experiment (INDOEX). Towards this goal, the nadir reflectance has been obtained by integrating INDOEX in-situ observations and a 3D Monte-Carlo Aerosol-Cloud radiation model. The comparison of 2D radiative transfer and independent pixel approximation (IPA) results demonstrates that IPA substantially underestimates nadir reflectances between the clouds. The effect can be explained by the radiative smoothing resulting from the horizontal photon transport. For the polluted cloud scene considered, the radiative smoothing is responsible for a 50% bias in aerosol optical depth retrieved between the clouds based on the plane-parallel theory.

  13. Incorporation of Three-dimensional Radiative Transfer into a Very High Resolution Simulation of Horizontally Inhomogeneous Clouds

    NASA Astrophysics Data System (ADS)

    Ishida, H.; Ota, Y.; Sekiguchi, M.; Sato, Y.

    2016-12-01

    A three-dimensional (3D) radiative transfer calculation scheme is developed to estimate horizontal transport of radiation energy in a very high resolution (with the order of 10 m in spatial grid) simulation of cloud evolution, especially for horizontally inhomogeneous clouds such as shallow cumulus and stratocumulus. Horizontal radiative transfer due to inhomogeneous clouds seems to cause local heating/cooling in an atmosphere with a fine spatial scale. It is, however, usually difficult to estimate the 3D effects, because the 3D radiative transfer often needs a large resource for computation compared to a plane-parallel approximation. This study attempts to incorporate a solution scheme that explicitly solves the 3D radiative transfer equation into a numerical simulation, because this scheme has an advantage in calculation for a sequence of time evolution (i.e., the scene at a time is little different from that at the previous time step). This scheme is also appropriate to calculation of radiation with strong absorption, such as the infrared regions. For efficient computation, this scheme utilizes several techniques, e.g., the multigrid method for iteration solution, and a correlated-k distribution method refined for efficient approximation of the wavelength integration. For a case study, the scheme is applied to an infrared broadband radiation calculation in a broken cloud field generated with a large eddy simulation model. The horizontal transport of infrared radiation, which cannot be estimated by the plane-parallel approximation, and its variation in time can be retrieved. The calculation result elucidates that the horizontal divergences and convergences of infrared radiation flux are not negligible, especially at the boundaries of clouds and within optically thin clouds, and the radiative cooling at lateral boundaries of clouds may reduce infrared radiative heating in clouds. In a future work, the 3D effects on radiative heating/cooling will be able to be

  14. Effect of High Doses of Radiation on Human Neutrophil Chemotaxis, Phagocytosis and Morphology

    PubMed Central

    Holley, Thomas R.; Van Epps, Dennis E.; Harvey, Ronald L.; Anderson, Robert E.; Williams, Ralph C.

    1974-01-01

    Human neutrophils were exposed to varying amounts of ionizing radiation up to 1,000,000 rad and evaluated as to their ability to respond to chemotactic stimuli and phagocytize and kill bacteria. Striking morphologic and functional resistance to radiation was apparent. At doses up to 5,000 rad there was little or no impairment of chemotaxis. As the dosage increased to 50,000 rad, chemotaxis decreased to approximately 50% of nonirradiated control values. At very high doses of radiation (250,000 to 1,000,000 rad) neutrophils failed to respond significantly to chemotactic stimuli. Effects of radiation as measured by phagocytosis and the degree of ultrastructural change paralleled the chemotaxis results. ImagesFig 3Fig 4AFigs 4B-CFig 1Fig 2 PMID:4596654

  15. Three-dimensional tomographic imaging for dynamic radiation behavior study using infrared imaging video bolometers in large helical device plasma

    SciTech Connect

    Sano, Ryuichi; Iwama, Naofumi; Peterson, Byron J.; Kobayashi, Masahiro; Mukai, Kiyofumi; Teranishi, Masaru; Pandya, Shwetang N.

    2016-05-15

    A three-dimensional (3D) tomography system using four InfraRed imaging Video Bolometers (IRVBs) has been designed with a helical periodicity assumption for the purpose of plasma radiation measurement in the large helical device. For the spatial inversion of large sized arrays, the system has been numerically and experimentally examined using the Tikhonov regularization with the criterion of minimum generalized cross validation, which is the standard solver of inverse problems. The 3D transport code EMC3-EIRENE for impurity behavior and related radiation has been used to produce phantoms for numerical tests, and the relative calibration of the IRVB images has been carried out with a simple function model of the decaying plasma in a radiation collapse. The tomography system can respond to temporal changes in the plasma profile and identify the 3D dynamic behavior of radiation, such as the radiation enhancement that starts from the inboard side of the torus, during the radiation collapse. The reconstruction results are also consistent with the output signals of a resistive bolometer. These results indicate that the designed 3D tomography system is available for the 3D imaging of radiation. The first 3D direct tomographic measurement of a magnetically confined plasma has been achieved.

  16. Three-dimensional tomographic imaging for dynamic radiation behavior study using infrared imaging video bolometers in large helical device plasma

    NASA Astrophysics Data System (ADS)

    Sano, Ryuichi; Peterson, Byron J.; Teranishi, Masaru; Iwama, Naofumi; Kobayashi, Masahiro; Mukai, Kiyofumi; Pandya, Shwetang N.

    2016-05-01

    A three-dimensional (3D) tomography system using four InfraRed imaging Video Bolometers (IRVBs) has been designed with a helical periodicity assumption for the purpose of plasma radiation measurement in the large helical device. For the spatial inversion of large sized arrays, the system has been numerically and experimentally examined using the Tikhonov regularization with the criterion of minimum generalized cross validation, which is the standard solver of inverse problems. The 3D transport code EMC3-EIRENE for impurity behavior and related radiation has been used to produce phantoms for numerical tests, and the relative calibration of the IRVB images has been carried out with a simple function model of the decaying plasma in a radiation collapse. The tomography system can respond to temporal changes in the plasma profile and identify the 3D dynamic behavior of radiation, such as the radiation enhancement that starts from the inboard side of the torus, during the radiation collapse. The reconstruction results are also consistent with the output signals of a resistive bolometer. These results indicate that the designed 3D tomography system is available for the 3D imaging of radiation. The first 3D direct tomographic measurement of a magnetically confined plasma has been achieved.

  17. Three-dimensional tomographic imaging for dynamic radiation behavior study using infrared imaging video bolometers in large helical device plasma.

    PubMed

    Sano, Ryuichi; Peterson, Byron J; Teranishi, Masaru; Iwama, Naofumi; Kobayashi, Masahiro; Mukai, Kiyofumi; Pandya, Shwetang N

    2016-05-01

    A three-dimensional (3D) tomography system using four InfraRed imaging Video Bolometers (IRVBs) has been designed with a helical periodicity assumption for the purpose of plasma radiation measurement in the large helical device. For the spatial inversion of large sized arrays, the system has been numerically and experimentally examined using the Tikhonov regularization with the criterion of minimum generalized cross validation, which is the standard solver of inverse problems. The 3D transport code EMC3-EIRENE for impurity behavior and related radiation has been used to produce phantoms for numerical tests, and the relative calibration of the IRVB images has been carried out with a simple function model of the decaying plasma in a radiation collapse. The tomography system can respond to temporal changes in the plasma profile and identify the 3D dynamic behavior of radiation, such as the radiation enhancement that starts from the inboard side of the torus, during the radiation collapse. The reconstruction results are also consistent with the output signals of a resistive bolometer. These results indicate that the designed 3D tomography system is available for the 3D imaging of radiation. The first 3D direct tomographic measurement of a magnetically confined plasma has been achieved.

  18. High-dose radiation-induced meningiomas following acute lymphoblastic leukemia in children.

    PubMed

    Salvati, M; Cervoni, L; Artico, M

    1996-05-01

    The authors review three personal cases of patients who developed cerebral meningiomas following high-dose radiotherapy for acute lymphoblastic leukemia. Two patients were female and one male. Their ages when the leukemia appeared were between 11 and 15 years. All patients were treated with a course of prophylactic irradiation to the neuraxis for a total dose of 24 Gy. After an average interval of 10.4 years, all three patients presented a meningioma; histologically, one was meningothelial and two were fibrous. All three meningiomas presented atypical features. At follow-up 1, 4, and 4 years respectively after surgery, none of these patients presents neurological deficits or neuroradiological signs of recurrence. Forty-nine cases of high-dose radiation-induced meningioma are also reviewed.

  19. Membrane Signaling Induced by High Doses of Ionizing Radiation in the Endothelial Compartment. Relevance in Radiation Toxicity

    PubMed Central

    Corre, Isabelle; Guillonneau, Maëva; Paris, François

    2013-01-01

    Tumor areas can now be very precisely delimited thanks to technical progress in imaging and ballistics. This has also led to the development of novel radiotherapy protocols, delivering higher doses of ionizing radiation directly to cancer cells. Despite this, radiation toxicity in healthy tissue remains a major issue, particularly with dose-escalation in these new protocols. Acute and late tissue damage following irradiation have both been linked to the endothelium irrigating normal tissues. The molecular mechanisms involved in the endothelial response to high doses of radiation are associated with signaling from the plasma membrane, mainly via the acid sphingomyelinase/ceramide pathway. This review describes this signaling pathway and discusses the relevance of targeting endothelial signaling to protect healthy tissues from the deleterious effects of high doses of radiation. PMID:24252908

  20. Three-Dimensional Conformal Radiation Therapy for Esophageal Squamous Cell Carcinoma: Is Elective Nodal Irradiation Necessary?

    SciTech Connect

    Zhao Kuaile; Ma Jinbo; Liu Guang; Wu Kailiang; Shi Xuehui; Jiang Guoliang

    2010-02-01

    Purpose: To evaluate the local control, survival, and toxicity associated with three-dimensional conformal radiotherapy (3D-CRT) for squamous cell carcinoma (SCC) of the esophagus, to determine the appropriate target volumes, and to determine whether elective nodal irradiation is necessary in these patients. Methods and Materials: A prospective study of 3D-CRT was undertaken in patients with esophageal SCC without distant metastases. Patients received 68.4 Gy in 41 fractions over 44 days using late-course accelerated hyperfractionated 3D-CRT. Only the primary tumor and positive lymph nodes were irradiated. Isolated out-of-field regional nodal recurrence was defined as a recurrence in an initially uninvolved regional lymph node. Results: All 53 patients who made up the study population tolerated the irradiation well. No acute or late Grade 4 or 5 toxicity was observed. The median survival time was 30 months (95% confidence interval, 17.7-41.8). The overall survival rate at 1, 2, and 3 years was 77%, 56%, and 41%, respectively. The local control rate at 1, 2, and 3 years was 83%, 74%, and 62%, respectively. Thirty-nine of the 53 patients (74%) showed treatment failure. Seventeen of the 39 (44%) developed an in-field recurrence, 18 (46%) distant metastasis with or without regional failure, and 3 (8%) an isolated out-of-field nodal recurrence only. One patient died of disease in an unknown location. Conclusions: In patients treated with 3D-CRT for esophageal SCC, the omission of elective nodal irradiation was not associated with a significant amount of failure in lymph node regions not included in the planning target volume. Local failure and distant metastases remained the predominant problems.

  1. Three-dimensional virtual histology of Silurian osteostracan scales revealed by synchrotron radiation microtomography.

    PubMed

    Qu, Qingming; Blom, Henning; Sanchez, Sophie; Ahlberg, Per

    2015-08-01

    We used propagation phase contrast X-ray synchrotron microtomography to study the three-dimensional (3D) histology of scales of two osteostracans, Tremataspis and Oeselaspis, members of a jawless vertebrate group often cited as the sister group of jawed vertebrates. 3D-models of the canal systems and other internal structures are assembled based on the virtual thin section datasets and compared with previous models based on real thin sections. The primary homology framework of the canal systems in the two taxa is revised and new histological details are revealed based on the results of this work. There is no separation of vascular canals and lower mesh canals in the Tremataspis scale, contrary to previous results. The secondary upper mesh canals have a limited distribution to the anterior region of the Tremataspis scale. The upper and lower mesh canal systems of Tremataspis have different geometries, inferred to reflect different developmental origins: we interpret the upper system as a probable epithelial invagination, the lower system as entirely vascular. Oeselaspis has no equivalent of the upper mesh canal system. The upper mesh canal system of Tremataspis may have been sensory in function. In Oeselaspis, numerous polyp-shaped structures opening from the canal system onto the surface of the scale resemble the innervation tracts for neuromast organs. The growth of the Oeselaspis scale proceeds by addition of small odontodes containing unmineralized lacunae, which may further mineralize and become more compact. Our results highlight that 3D-histological investigation on scales and other dermal skeletons of osteostracans is necessary to fully appreciate the diversity of skeletal histologies in the group. Traditional 3D-models based on thin sections alone are not reliable and should no longer be used as the basis for homology assessments or functional hypotheses. © 2015 Wiley Periodicals, Inc.

  2. Analysis of global radiation budgets and cloud forcing using three-dimensional cloud nephanalysis data base. Master's thesis

    SciTech Connect

    Mitchell, B.

    1990-12-01

    A one-dimensional radiative transfer model was used to compute the global radiative budget at the top of the atmosphere (TOA) and the surface for January and July. 1979. The model was also used to determine the global cloud radiative forcing for all clouds and for high and low cloud layers. In the computations. the authors used the monthly cloud data derived from the Air Force Three-Dimensional Cloud Nephanalysis (3DNEPH). These data were used in conjunction with conventional temperature and humidity profiles analyzed during the 1979 First GARP (Global Atmospheric Research Program) Global Experiment (FGGE) year. Global surface albedos were computed from available data and were included in the radiative transfer analysis. Comparisons of the model-produced outgoing solar and infrared fluxes with those derived from Nimbus 7 Earth Radiation Budget (ERS) data were made to validate the radiative model and cloud cover. For reflected solar and emitted infrared (IR) flux, differences within 20 w/sq m meters were shown.

  3. Silicon-based three-dimensional microstructures for radiation dosimetry in hadrontherapy

    SciTech Connect

    Guardiola, C. Solberg, T.; Carabe, A.; Quirion, D.; Pellegrini, G.; Fleta, C.; Esteban, S.; Lozano, M.; Cortés-Giraldo, M. A.; Gómez, F.

    2015-07-13

    In this work, we propose a solid-state-detector for use in radiation microdosimetry. This device improves the performance of existing dosimeters using customized 3D-cylindrical microstructures etched inside silicon. The microdosimeter consists of an array of micro-sensors that have 3D-cylindrical electrodes of 15 μm diameter and a depth of 5 μm within a silicon membrane, resulting in a well-defined micrometric radiation sensitive volume. These microdetectors have been characterized using an {sup 241}Am source to assess their performance as radiation detectors in a high-LET environment. This letter demonstrates the capability of this microdetector to be used to measure dose and LET in hadrontherapy centers for treatment plan verification as part of their patient-specific quality control program.

  4. Silicon-based three-dimensional microstructures for radiation dosimetry in hadrontherapy

    NASA Astrophysics Data System (ADS)

    Guardiola, C.; Quirion, D.; Pellegrini, G.; Fleta, C.; Esteban, S.; Cortés-Giraldo, M. A.; Gómez, F.; Solberg, T.; Carabe, A.; Lozano, M.

    2015-07-01

    In this work, we propose a solid-state-detector for use in radiation microdosimetry. This device improves the performance of existing dosimeters using customized 3D-cylindrical microstructures etched inside silicon. The microdosimeter consists of an array of micro-sensors that have 3D-cylindrical electrodes of 15 μm diameter and a depth of 5 μm within a silicon membrane, resulting in a well-defined micrometric radiation sensitive volume. These microdetectors have been characterized using an 241Am source to assess their performance as radiation detectors in a high-LET environment. This letter demonstrates the capability of this microdetector to be used to measure dose and LET in hadrontherapy centers for treatment plan verification as part of their patient-specific quality control program.

  5. [High-dose radiation-induced meningioma following prophylactic cranial irradiation for acute lymphoblastic leukaemia].

    PubMed

    Matsuda, Ryosuke; Nikaido, Yuji; Yamada, Tomonori; Mishima, Hideaki; Tamaki, Ryo

    2005-03-01

    A 12 year-old girl was treated with prophylatic cranial irradiation for acute lymphoblastic leukaemia (ALL). At the age of 39, she was admitted to our hospital for status epilepticus. Computed tomography demonstrated two, enhancing bilateral sided intracranial tumors. After surgery, this patient presented meningiomas which histologically, were of the meningothelial type. The high cure rate in childhood ALL, attributable to aggressive chemotherapy and prophylatic cranial irradiation, is capable of inducing secondary brain tumor. Twelve cases of high-dose radiation-induced meningioma following ALL are also reviewed.

  6. Radiation dose delivered to the proximal penis as a predictor of the risk of erectile dysfunction after three-dimensional conformal radiotherapy for localized prostate cancer

    SciTech Connect

    Wernicke, A. Gabriella; Valicenti, Richard . E-mail: richard.valicenti@mail.tju.edu; DiEva, Kelly; Houser, Christopher; Pequignot, Ed

    2004-12-01

    Purpose/objective: In this study, we evaluated in a serial manner whether radiation dose to the bulb of the penis is predictive of erectile dysfunction, ejaculatory difficulty (EJ), and overall satisfaction with sex life (quality of life) by using serial validated self-administered questionnaires. Methods and materials: Twenty-nine potent men with AJCC Stage II prostate cancer treated with three-dimensional conformal radiation therapy alone to a median dose 72.0 Gy (range: 66.6-79.2 Gy) were evaluated by determining the doses received by the penile bulb. The penile bulb was delineated volumetrically, and the dose-volume histogram was obtained on each patient. Results: The median follow-up time was 35 months (range, 16-43 months). We found that for D{sub 30}, D{sub 45}, D{sub 60}, and D{sub 75} (doses to a percent volume of PB: 30%, 45%, 60%, and 75%), higher than the corresponding median dose (defined as high-dose group) correlated with an increased risk of impotence (erectile dysfunction firmness score = 0) (odds ratio [OR] = 7.5, p = 0.02; OR = 7.5, p = 0.02; OR = 8.6, p = 0.008; and OR = 6.9, p = 0.015, respectively). Similarly, for EJD D{sub 30}, D{sub 45}, D{sub 60}, and D{sub 75}, doses higher than the corresponding median ones correlated with worsening ejaculatory function score (EJ = 0 or 1) (OR = 8, p = 0.013; OR = 8, p 0.013; OR = 9.2, p = 0.015; and OR = 8, p = 0.026, respectively). For quality of life, low ({<=}median dose) dose groups of patients improve over time, whereas high-dose groups of patients worsen. Conclusions: This study supports the existence of a penile bulb dose-volume relationship underlying the development of radiation-induced erectile dysfunction. Our data may guide the use of inverse treatment planning to maximize the probability of maintaining sexual potency after radiation therapy.

  7. Radiation Parameterization for Three-Dimensional Inhomogeneous Cirrus Clouds Applied to ARM Data and Climate Models

    SciTech Connect

    Kuo-Nan Liou

    2003-12-29

    OAK-B135 (a) We developed a 3D radiative transfer model to simulate the transfer of solar and thermal infrared radiation in inhomogeneous cirrus clouds. The model utilized a diffusion approximation approach (four-term expansion in the intensity) employing Cartesian coordinates. The required single-scattering parameters, including the extinction coefficient, single-scattering albedo, and asymmetry factor, for input to the model, were parameterized in terms of the ice water content and mean effective ice crystal size. The incorporation of gaseous absorption in multiple scattering atmospheres was accomplished by means of the correlated k-distribution approach. In addition, the strong forward diffraction nature in the phase function was accounted for in each predivided spatial grid based on a delta-function adjustment. The radiation parameterization developed herein is applied to potential cloud configurations generated from GCMs to investigate broken clouds and cloud-overlapping effects on the domain-averaged heating rate. Cloud inhomogeneity plays an important role in the determination of flux and heating rate distributions. Clouds with maximum overlap tend to produce less heating than those with random overlap. Broken clouds show more solar heating as well as more IR cooling as compared to a continuous cloud field (Gu and Liou, 2001). (b) We incorporated a contemporary radiation parameterization scheme in the UCLA atmospheric GCM in collaboration with the UCLA GCM group. In conjunction with the cloud/radiation process studies, we developed a physically-based cloud cover formation scheme in association with radiation calculations. The model clouds were first vertically grouped in terms of low, middle, and high types. Maximum overlap was then used for each cloud type, followed by random overlap among the three cloud types. Fu and Liou's 1D radiation code with modification was subsequently employed for pixel-by-pixel radiation calculations in the UCLA GCM. We showed

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

    SciTech Connect

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

    2005-04-01

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

  9. Three-dimensional relativistic pair plasma reconnection with radiative feedback in the Crab Nebula

    SciTech Connect

    Cerutti, B.; Werner, G. R.; Uzdensky, D. A.; Begelman, M. C. E-mail: greg.werner@colorado.edu E-mail: mitch@jila.colorado.edu

    2014-02-20

    The discovery of rapid synchrotron gamma-ray flares above 100 MeV from the Crab Nebula has attracted new interest in alternative particle acceleration mechanisms in pulsar wind nebulae. Diffuse shock-acceleration fails to explain the flares because particle acceleration and emission occur during a single or even sub-Larmor timescale. In this regime, the synchrotron energy losses induce a drag force on the particle motion that balances the electric acceleration and prevents the emission of synchrotron radiation above 160 MeV. Previous analytical studies and two-dimensional (2D) particle-in-cell (PIC) simulations indicate that relativistic reconnection is a viable mechanism to circumvent the above difficulties. The reconnection electric field localized at X-points linearly accelerates particles with little radiative energy losses. In this paper, we check whether this mechanism survives in three dimension (3D), using a set of large PIC simulations with radiation reaction force and with a guide field. In agreement with earlier works, we find that the relativistic drift kink instability deforms and then disrupts the layer, resulting in significant plasma heating but few non-thermal particles. A moderate guide field stabilizes the layer and enables particle acceleration. We report that 3D magnetic reconnection can accelerate particles above the standard radiation reaction limit, although the effect is less pronounced than in 2D with no guide field. We confirm that the highest-energy particles form compact bunches within magnetic flux ropes, and a beam tightly confined within the reconnection layer, which could result in the observed Crab flares when, by chance, the beam crosses our line of sight.

  10. Long-term androgen deprivation increases Grade 2 and higher late morbidity in prostate cancer patients treated with three-dimensional conformal radiation therapy

    SciTech Connect

    Feigenberg, Steven J. . E-mail: S_Feigenberg@fccc.edu; Hanlon, Alexandra L.; Horwitz, Eric M.; Uzzo, Robert G.; Eisenberg, Debra; Pollack, Alan

    2005-06-01

    Purpose: To determine whether the use of androgen deprivation (AD) increases late morbidity when combined with high-dose three-dimensional conformal radiation therapy (3D-CRT). Methods and materials: Between May 1989 and November 1998, 1,204 patients were treated for prostate cancer with 3D-CRT to a median dose of 74 Gy. Patients were evaluated every 3-6 months. No AD was given to 945 patients, whereas 140 and 119 patients, respectively, received short-term AD (STAD; {<=}6 months) and long-term AD (LTAD; > 6 months). Radiation morbidity was graded according to the Fox Chase modification of the Late Effects Normal Tissue Task Force late morbidity scale. Covariates in the multivariate analysis (MVA) included age, history of diabetes mellitus, prostate-specific antigen (PSA) level, Gleason score, T category, RT field size, total RT dose, use of rectal shielding, and AD status (no AD vs. STAD vs. LTAD). Results: The only independent predictor for Grade 2 or higher genitourinary (GU) morbidity in the MVA was the use of AD (p = 0.0065). The 5-year risk of Grade 2 or higher GU morbidity was 8% for no AD, 8% for STAD, and 14% for LTAD (p = 0.02). Independent predictors of Grade 2 or higher gastrointestinal (GI) morbidity in the MVA were the use of AD (p = 0.0079), higher total radiation dose (p < 0.0001), the lack of a rectal shield (p = 0.0003), and older age (p = 0.0009). The 5-year actuarial risk of Grade 2 or higher GI morbidity was 17% for no AD vs. 18% for STAD and 26% for LTAD (p = 0.017). Conclusions: The use of LTAD seems to significantly increase the risk of both GU and GI morbidity for patients treated with 3D-CRT.

  11. Therapy of locally unresectable pancreatic carcinoma: a randomized comparison of high dose (6000 rads) radiation alone, moderate dose radiation (4000 rads + 5-fluorouracil), and high dose radiation + 5-fluorouracil: the Gastrointestinal Tumor Study Group. [X ray

    SciTech Connect

    Moertel, C.G.; Frytak, S.; Hahn, R.G.

    1981-10-15

    One-hundred-ninety-four eligible and evaluable patients with histologically confirmed locally unresectable adenocarcinoma of the pancreas were randomly assigned to therapy with high-dose (6000 rads) radiation therapy alone, to moderate-dose (4000 rads) radiation + 5-fluorouracil (5-FU), and to high-dose radiation plus 5-FU. Median survival with radiation alone was only 5 1/2 months from date of diagnosis. Both 5-FU-containing treatment regimens produced a highly significant survival improvement when compared with radiation alone. Survival differences between 4000 rads plus 5-FU and 6000 rads plus 5-FU were not significant with an overall median survival of ten months. Significant prognostic variables, in addition to treatment, were pretreatment performance status and pretreatment CEA level. The toxic reactions related to the treatment are discussed.

  12. A Novel Implementation of Massively Parallel Three Dimensional Monte Carlo Radiation Transport

    NASA Astrophysics Data System (ADS)

    Robinson, P. B.; Peterson, J. D. L.

    2005-12-01

    The goal of our summer project was to implement the difference formulation for radiation transport into Cosmos++, a multidimensional, massively parallel, magneto hydrodynamics code for astrophysical applications (Peter Anninos - AX). The difference formulation is a new method for Symbolic Implicit Monte Carlo thermal transport (Brooks and Szöke - PAT). Formerly, simultaneous implementation of fully implicit Monte Carlo radiation transport in multiple dimensions on multiple processors had not been convincingly demonstrated. We found that a combination of the difference formulation and the inherent structure of Cosmos++ makes such an implementation both accurate and straightforward. We developed a "nearly nearest neighbor physics" technique to allow each processor to work independently, even with a fully implicit code. This technique coupled with the increased accuracy of an implicit Monte Carlo solution and the efficiency of parallel computing systems allows us to demonstrate the possibility of massively parallel thermal transport. This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48

  13. Effect of ionizing radiation on acinar morphogenesis of human prostatic epithelial cells under three-dimensional culture conditions.

    PubMed

    Wang, T; X, S Ma; Kong, D; Yi, H; Wang, X; Liang, B; Xu, H; He, M; Jia, L; Qased, A B; Yang, Y; Liu, X

    2012-01-01

    Homeostasis is maintained by the interplay of multiple factors that directly or indirectly regulate cell proliferation and cell death. Complex multiple interactions between cells and the extracellular matrix occur during acinar morphogenesis and changes in these might indicate carcinogenesis of cells from a normal to a malignant, invasive phenotype. In this study, the human prostatic epithelial cell line RWPE-1 was cultured under three-dimensional (3-D) culture conditions, and the effect of ionizing radiation on acinar morphogenesis and its association with autophagy were discussed. The results illustrated that formation of specific spheroid (acinar) structures was detectable under 3-D culture conditions. Radiation induced the disruption of acini in different cell models using either gene overexpression (Akt) or gene knock-down (Beclin 1 and ATG7). Introduction of Akt not only accelerated the growth of cells (i.e., caused the cells to manifest elongating and microspike-like structures that are obviously different from structures seen in wild-type RWPE-1 cells under two-dimensional conditions), but also changed their morphological characteristics under 3-D culture conditions. Knock-down of autophagy-related genes (Beclin 1 and ATG7) increased the radiosensitivity of cells under 3-D culture conditions, and cells died of non-apoptotic death after radiation. The results suggested that ionizing radiation may change the cell phenotype and the formation of acini. Additionally even the autophagy mechanism may play a role in these processes.

  14. Three-dimensional radiation dosimetry using polymer gel and solid radiochromic polymer: From basics to clinical applications

    PubMed Central

    Watanabe, Yoichi; Warmington, Leighton; Gopishankar, N

    2017-01-01

    Accurate dose measurement tools are needed to evaluate the radiation dose delivered to patients by using modern and sophisticated radiation therapy techniques. However, the adequate tools which enable us to directly measure the dose distributions in three-dimensional (3D) space are not commonly available. One such 3D dose measurement device is the polymer-based dosimeter, which changes the material property in response to radiation. These are available in the gel form as polymer gel dosimeter (PGD) and ferrous gel dosimeter (FGD) and in the solid form as solid plastic dosimeter (SPD). Those are made of a continuous uniform medium which polymerizes upon irradiation. Hence, the intrinsic spatial resolution of those dosimeters is very high, and it is only limited by the method by which one converts the dose information recorded by the medium to the absorbed dose. The current standard methods of the dose quantification are magnetic resonance imaging, optical computed tomography, and X-ray computed tomography. In particular, magnetic resonance imaging is well established as a method for obtaining clinically relevant dosimetric data by PGD and FGD. Despite the likely possibility of doing 3D dosimetry by PGD, FGD or SPD, the tools are still lacking wider usages for clinical applications. In this review article, we summarize the current status of PGD, FGD, and SPD and discuss the issue faced by these for wider acceptance in radiation oncology clinic and propose some directions for future development. PMID:28396725

  15. Spot Radiative Ignition and Subsequent Three Dimensional Flame Spread Over Thin Cellulose Fuels

    NASA Technical Reports Server (NTRS)

    Olson, Sandra L.; Kashiwagi, T.; Kikuchi, M.; Fujita, O.; Ito, K.

    1999-01-01

    Spontaneous radiative ignition and transition to flame spread over thin cellulose fuel samples was studied aboard the USMP-3 STS-75 Space Shuttle mission, and in three test series in the 10 second Japan Microgravity Center (JAMIC). A focused beam from a tungsten/halogen lamp was used to ignite the center of the fuel sample while an external air flow was varied from 0 to 10 cm/s. Non-piloted radiative ignition of the paper was found to occur more easily in microgravity than in normal gravity. Ignition of the sample was achieved under all conditions studied (shuttle cabin air, 21%-50% O2 in JAMIC), with transition to flame spread occurring for all but the lowest oxygen and flow conditions. While radiative ignition in a quiescent atmosphere was achieved, the flame quickly extinguished in air. The ignition delay time was proportional to the gas-phase mixing time, which is estimated using the inverse flow rate. The ignition delay was a much stronger function of flow at lower oxygen concentrations. After ignition, the flame initially spread only upstream, in a fan-shaped pattern. The fan angle increased with increasing external flow and oxygen concentration from zero angle (tunneling flame spread) at the limiting 0.5 cm/s external air flow, to 90 degrees (semicircular flame spread) for external flows at and above 5 cm/s, and higher oxygen concentrations. The fan angle was shown to be directly related to the limiting air flow velocity. Despite the convective heating from the upstream flame, the downstream flame was inhibited due to the 'oxygen shadow' of the upstream flame for the air flow conditions studied. Downstream flame spread rates in air, measured after upstream flame spread was complete and extinguished, were slower than upstream flame spread rates at the same flow. The quench regime for the transition to flame spread was skewed toward the downstream, due to the augmenting role of diffusion for opposed flow flame spread, versus the canceling effect of diffusion

  16. Modelling of three-dimensional transient conjugate convection-conduction-radiation heat transfer processes and turbulence in building spaces

    NASA Astrophysics Data System (ADS)

    Potter, Stephen Edward

    1998-12-01

    A survey of the developments in the field of Computational Fluid Dynamics (CFD) is presented the results of which are used to identify numerical methods capable of solving the equation sets that define the various categories of fluid flow and heat transfer that apply to air movement within buildings. The background to turbulence modelling is discussed together with the treatment of near-wall regions to which turbulence models are inapplicable. A further survey into the application of CFD methods to air movement within buildings is presented together with an appraisal of the success of these studies in terms of realistic modelling. From this survey it is concluded that there is a need to integrate surface radiation heat transfer methods within CFD procedures in order to provide a fully coupled model. The equation set describing advection, convection and conduction processes together with the k-ɛ turbulence model are presented and the development of this equation set into the final mathematical model described. Details of the numerical procedure adopted for solution of the equation set are provided together with a general approach to the incorporation of radiation heat transfer within the same solution scheme. Shortwave and longwave radiation heat transfer processes in buildings are discussed and the geometric requirements for the numerical simulation of radiation process identified. A general numerical method for handling room geometry is presented together with a method for linking building surface and CFD grid geometries. A method for incorporating shortwave solar radiation together with an approximate method for longwave radiation within the CFD solution scheme is detailed dispensing with the need for an involved iterative approach. A computer program has been developed from these mathematical models which is capable of solving coupled three-dimensional convection, conduction and radiation heat transfer processes. The program has been applied to a set of test

  17. Polarized radiance fields under a dynamic ocean surface: a three-dimensional radiative transfer solution.

    PubMed

    You, Yu; Zhai, Peng-Wang; Kattawar, George W; Yang, Ping

    2009-06-01

    The hybrid matrix operator, Monte Carlo (HMOMC) method previously reported [Appl. Opt.47, 1063-1071 (2008)] is improved by neglecting higher-order terms in the coupling of the matrix operators and by introducing a dual grid scheme. The computational efficiency for solving the vector radiative transfer equation in a full 3D coupled atmosphere-surface-ocean system is substantially improved, and, thus, large-scale simulations of the radiance distribution become feasible. The improved method is applied to the computation of the polarized radiance field under realistic surface waves simulated by the power spectral density method. To the authors' best knowledge, this is the first time that the polarized radiance field under a dynamic ocean surface and the underwater image of an object above such an ocean surface have been reported.

  18. High-dose MVCT image guidance for stereotactic body radiation therapy

    SciTech Connect

    Westerly, David C.; Schefter, Tracey E.; Kavanagh, Brian D.; Chao, Edward; Lucas, Dan; Flynn, Ryan T.; Miften, Moyed

    2012-08-15

    Purpose: Stereotactic body radiation therapy (SBRT) is a potent treatment for early stage primary and limited metastatic disease. Accurate tumor localization is essential to administer SBRT safely and effectively. Tomotherapy combines helical IMRT with onboard megavoltage CT (MVCT) imaging and is well suited for SBRT; however, MVCT results in reduced soft tissue contrast and increased image noise compared with kilovoltage CT. The goal of this work was to investigate the use of increased imaging doses on a clinical tomotherapy machine to improve image quality for SBRT image guidance. Methods: Two nonstandard, high-dose imaging modes were created on a tomotherapy machine by increasing the linear accelerator (LINAC) pulse rate from the nominal setting of 80 Hz, to 160 Hz and 300 Hz, respectively. Weighted CT dose indexes (wCTDIs) were measured for the standard, medium, and high-dose modes in a 30 cm solid water phantom using a calibrated A1SL ion chamber. Image quality was assessed from scans of a customized image quality phantom. Metrics evaluated include: contrast-to-noise ratios (CNRs), high-contrast spatial resolution, image uniformity, and percent image noise. In addition, two patients receiving SBRT were localized using high-dose MVCT scans. Raw detector data collected after each scan were used to reconstruct standard-dose images for comparison. Results: MVCT scans acquired using a pitch of 1.0 resulted in wCTDI values of 2.2, 4.7, and 8.5 cGy for the standard, medium, and high-dose modes respectively. CNR values for both low and high-contrast materials were found to increase with the square root of dose. Axial high-contrast spatial resolution was comparable for all imaging modes at 0.5 lp/mm. Image uniformity was improved and percent noise decreased as the imaging dose increased. Similar improvements in image quality were observed in patient images, with decreases in image noise being the most notable. Conclusions: High-dose imaging modes are made possible on a

  19. Impact of Three-Dimensional Radiative Effects on Satellite Retrievals of Cloud Droplet Sizes

    NASA Technical Reports Server (NTRS)

    Marshak, Alexander; Platnick, Steven; Varnai, Tamas; Wen, Guoyong; Cahalan, Robert F.

    2006-01-01

    There are several dozen papers that study the effects of cloud horizontal inhomogeneity on the retrievals of cloud optical thickness, but only a few of them deal with cloud droplet sizes. This paper is one of the first comprehensive attempts to fill this gap: It takes a close theoretical look at the radiative effects of cloud 3-D structure in retrievals of droplet effective radii. Under some general assumptions, it was found that ignoring subpixel (unresolved) variability produces a negative bias in the retrieved effective radius, while ignoring cloud inhomogeneity at scales larger than a pixel scale (resolved variability), on the contrary, leads to overestimation of the domain average droplet size. The theoretical results are illustrated with examples from Large Eddy Simulations (LES) of cumulus (Cu) and stratocumulus (Sc) cloud fields. The analysis of cloud drop size distributions retrieved from both LES fields confirms that ignoring shadowing in 1-D retrievals results in substantial overestimation of effective radii which is more pronounced for broken Cu than for Sc clouds. Collocated measurements of broken Cu clouds by Moderate Resolution Imaging Spectrometer (MODIS) and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) are used to check simulations and theory with observations. The analysis of ASTER and MODIS data and associated derived products recommends against blindly using retrieved effective radii for broken cloud fields, especially if one wants to relate aerosol amounts to cloud droplet sizes.

  20. MAGIC-type polymer gel for three-dimensional dosimetry: intensity-modulated radiation therapy verification.

    PubMed

    Gustavsson, Helen; Karlsson, Anna; Bäck, Sven A J; Olsson, Lars E; Haraldsson, Pia; Engström, Per; Nyström, Håkan

    2003-06-01

    A new type of polymer gel dosimeter, which responds well to absorbed dose even when manufactured in the presence of normal levels of oxygen, was recently described by Fong et al. [Phys. Med. Biol. 46, 3105-3113 (2001)] and referred to by the acronym MAGIC. The aim of this study was to investigate the feasibility of using this new type of gel for intensity-modulated radiation therapy (IMRT) verification. Gel manufacturing was carried out in room atmosphere under normal levels of oxygen. IMRT inverse treatment planning was performed using the Helios software. The gel was irradiated using a linear accelerator equipped with a dynamic multileaf collimator, and intensity modulation was achieved using sliding window technique. The response to absorbed dose was evaluated using magnetic resonance imaging. Measured and calculated dose distributions were compared with regard to in-plane isodoses and dose volume histograms. In addition, the spatial and dosimetric accuracy was evaluated using the gamma formalism. Good agreement between calculated and measured data was obtained. In the isocenter plane, the 70% and 90% isodoses acquired using the different methods are mostly within 2 mm, with up to 3 mm disagreement at isolated points. For the planning target volume (PTV), the calculated mean relative dose was 96.8 +/- 2.5% (1 SD) and the measured relative mean dose was 98.6 +/- 2.2%. Corresponding data for an organ at risk was 34.4 +/- 0.9% and 32.7 +/- 0.7%, respectively. The gamma criterion (3 mm spatial/3% dose deviation) was fulfilled for 94% of the pixels in the target region. Discrepancies were found in hot spots the upper and lower parts of the PTV, where the measured dose was up to 11% higher than calculated. This was attributed to sub optimal scatter kernels used in the treatment planning system dose calculations. Our results indicate great potential for IMRT verification using MAGIC-type polymer gel.

  1. Attenuation of Radiated Ground Motion and Stresses from Three-Dimensional Supershear Ruptures

    NASA Astrophysics Data System (ADS)

    Bhat, H. S.; Dunham, E. M.

    2007-12-01

    Radiating shear and Rayleigh waves from supershear ruptures form Mach fronts that transmit large-amplitude ground motion and stresses to locations far from the fault. We simulate bilateral ruptures on a finite-width vertical strike-slip fault (of width W and half-length L with L >> W) breaking the surface of an elastic half-space, and focus on the wavefield out to distances comparable to L. At distances much smaller than W, two- dimensional plane-strain slip-pulse models (i.e., models in which the lateral extent of the slip zone is unbounded) [Dunham, 2005; Bhat et al., 2007] accurately predict the subsurface wavefield. Amplitudes in the shear Mach wedges of those models are undiminished with distance from the fault. When viewed from distances far greater than W, the fault is accurately modeled as a line source that produces a shear Mach cone and, on the free surface, a Rayleigh Mach wedge. Geometrical spreading of the shear Mach cone occurs radially and amplitudes there decrease with the inverse square-root of distance [Ben-Menahem and Singh, 1987]. The transition between these two asymptotic limits occurs at distances comparable to W. Similar considerations suggest that Rayleigh Mach waves suffer no attenuation in the ideally elastic medium studied here. The rate at which fault strength weakens at the rupture front exerts a strong influence on the off-fault fields only in the immediate vicinity of the fault (for both sub-Rayleigh and supershear ruptures) and at the Mach fronts of supershear ruptures. More rapid weakening generates larger amplitudes at the Mach fronts. A paper has been prepared on this topic, with title the same as for this abstract, by E. M. Dunham and H. S. Bhat, submitted to \\it{J. Geophys. Res.}

  2. CHEMISTRY IN THE FIRST HYDROSTATIC CORE STAGE BY ADOPTING THREE-DIMENSIONAL RADIATION HYDRODYNAMIC SIMULATIONS

    SciTech Connect

    Furuya, Kenji; Aikawa, Yuri; Tomida, Kengo; Tomisaka, Kohji; Matsumoto, Tomoaki; Saigo, Kazuya; Hersant, Franck; Wakelam, Valentine

    2012-10-20

    We investigate molecular evolution from a molecular cloud core to a first hydrostatic core in three spatial dimensions. We perform a radiation hydrodynamic simulation in order to trace fluid parcels, in which molecular evolution is investigated, using a gas-phase and grain-surface chemical reaction network. We derive spatial distributions of molecular abundances and column densities in the molecular cloud core harboring the first core. We find that the total gas and ice abundances of many species in a cold era (10 K) remain unaltered until the temperature reaches {approx}500 K. The gas abundances in the warm envelope and the outer layer of the first core (T {approx}< 500 K) are mainly determined via the sublimation of ice-mantle species. Above 500 K, the abundant molecules, such as H{sub 2}CO, start to be destroyed, and simple molecules, such as CO, H{sub 2}O, and N{sub 2}, are reformed. On the other hand, some molecules are effectively formed at high temperature; carbon chains, such as C{sub 2}H{sub 2} and cyanopolyynes, are formed at temperatures >700 K. We also find that large organic molecules, such as CH{sub 3}OH and HCOOCH{sub 3}, are associated with the first core (r {approx}< 10 AU). Although the abundances of these molecules in the first core stage are comparable to or less than in the protostellar stage (hot corino), reflecting the lower luminosity of the central object, their column densities in our model are comparable to the observed values toward the prototypical hot corino, IRAS 16293-2422. We propose that these large organic molecules can be good tracers of the first cores.

  3. Radiation-induced liver disease in three-dimensional conformal radiation therapy for primary liver carcinoma: The risk factors and hepatic radiation tolerance

    SciTech Connect

    Liang Shixiong; Zhu Xiaodong; Xu Zhiyong

    2006-06-01

    Purpose: To identify risk factors relevant to radiation-induced liver disease (RILD) and to determine the hepatic tolerance to radiation. Methods and Materials: The data of 109 primary liver carcinomas (PLC) treated with hypofractionated three-dimensional conformal radiation therapy (3D-CRT) were analyzed. Seventeen patients were diagnosed with RILD and 13 of 17 died of it. Results: The risk factors for RILD were late T stage, large gross tumor volume, presence of portal vein thrombosis, association with Child-Pugh Grade B cirrhosis, and acute hepatic toxicity. Multivariate analyses demonstrated that the severity of hepatic cirrhosis was a unique independent predictor. For Child-Pugh Grade A patients, the hepatic radiation tolerance was as follows: (1) Mean dose to normal liver (MDTNL) of 23 Gy was tolerable. (2) For cumulative dose-volume histogram, the tolerable volume percentages would be less than: V{sub 5} of 86%, V{sub 1} of 68%, V{sub 15} of 59%, V{sub 2} of 49%, V{sub 25} of 35%, V{sub 3} of 28%, V{sub 35} of 25%, and V{sub 4} of 20%. (3) Tolerable MDTNL could be estimated by MDTNL (Gy) = -1.686 + 0.023 * normal liver volume (cm{sup 3}). Conclusion: The predominant risk factor for RILD was the severity of hepatic cirrhosis. The hepatic tolerance to radiation could be estimated by dosimetric parameters.

  4. Three-dimensional Non-LTE Radiative Transfer of CS in Clumpy Dense Cores

    NASA Astrophysics Data System (ADS)

    Park, Y.-S.; Hong, S. S.

    1998-02-01

    With a Monte Carlo radiative transfer code we have investigated excitation conditions of the CS molecule in dense cores and synthesized line profiles for several transitions of both CS and C34S. We took two kinds of models of the dense core: a clumpy and a smooth model. In the clumpy model, the core is composed of many small clumps, whose volume filling factor f is unity in the central region of r <= 0.2R and then declines as f ~ r-1.5. However, H2 number density in the clump is kept constant and also independent of the clump position. The mean number density, nH2(r), is thus constant in the central part and then decreases as the same power law. In the smooth model, the gas fills the core completely, and its local density exactly follows the mean density of the clumpy model. For both models, each clump has thermal as well as bulk motions, velocity dispersion of the latter being proportional to r0.5. In the clumpy structured core, the excitation temperature of the CS transitions is found to be generally constant over an entire region. As a consequence, the synthesized profile is of a Gaussian shape superposed with some wiggles, which reflects the existence of clumps under the bulk motion. The trend of flat distribution of excitation temperature becomes more prominent for optically thin transitions of the rarer species C34S. The profiles develop flat-top features with minor wiggles only when the core becomes extremely thick in the optical sense. On the other hand, wider profiles that have self-absorption are synthesized in the smooth core. The self-absorption is formed by a steep gradient in the radial distribution of the excitation temperature. For optically thin C34S transitions, both the clumpy and the smooth cores exhibit profiles close to a Gaussian shape. Comparing line parameters derived in the Monte Carlo code and those by the large-scale velocity gradient calculations, we found that only the clumpy models can give correct estimations of the density and

  5. Demonstration of three-dimensional deterministic radiation transport theory dose distribution analysis for boron neutron capture therapy.

    PubMed

    Nigg, D W; Randolph, P D; Wheeler, F J

    1991-01-01

    The Monte Carlo stochastic simulation technique has traditionally been the only well-recognized method for computing three-dimensional radiation dose distributions in connection with boron neutron capture therapy (BNCT) research. A deterministic approach to this problem would offer some advantages over the Monte Carlo method. This paper describes an application of a deterministic method to analytically simulate BNCT treatment of a canine head phantom using the epithermal neutron beam at the Brookhaven medical research reactor (BMRR). Calculations were performed with the TORT code from Oak Ridge National Laboratory (ORNL), an implementation of the discrete ordinates, or Sn method. Calculations were from first principles and used no empirical correction factors. The phantom surface was modeled by flat facets of approximately 1 cm2. The phantom interior was homogeneous. Energy-dependent neutron and photon scalar fluxes were calculated on a 32 x 16 x 22 mesh structure with 96 discrete directions in angular phase space. The calculation took 670 min on an Apollo DN10000 workstation. The results were subsequently integrated over energy to obtain full three-dimensional dose distributions. Isodose contours and depth-dose curves were plotted for several separate dose components of interest. Phantom measurements were made by measuring neutron activation (and therefore neutron flux) as a function of depth in copper-gold alloy wires that were inserted through catheters placed in holes drilled in the phantom. Measurements agreed with calculations to within about 15%. The calculations took about an order of magnitude longer than comparable Monte Carlo calculations but provided various conveniences, as well as a useful check.

  6. An ultra-high dose of electron radiation response of Germanium Flat Fiber and TLD-100

    NASA Astrophysics Data System (ADS)

    Alawiah, A.; Amin, Y. M.; Abdul-Rashid, H. A.; Abdullah, W. S. Wan; Maah, M. J.; Bradley, D. A.

    2017-01-01

    The thermoluminescence (TL) response of Germanium Flat Fiber (GFF) and TLD-100 irradiated with 2.5 MeV electrons for the doses up to 1 MGy were studied and compared. The aim was to evaluate the TL supralinearity response at an ultra-high dose (UHD) range and to investigate the change in kinetic parameters of the glow peaks, as the doses increases up to 1 MGy. It is found that the critical dose limit (CDL) of GFF is 5 times higher as compared to TLD-100. CDL is determined by the dose at the maximum supralinearity, f(D)max. It is also found that annealing the TLD-100 and GFF with temperature more than 400 °C is required to reset it back to its original condition, following radiation doses up to 1 MGy. It is also noticed the strange behavior of Peak 4 (TLD-100), which tends to be invisible at the lower dose (<10 kGy) and starts to be appeared at the critical dose limit of 10 kGy. This result might be an important clue to understand the behavior of TLD-100 at extremely high dose range. For both samples, it is observed that the TL intensity is not saturated within the UHD range studied.

  7. Acute Exposure to High Dose γ-Radiation Results in Transient Activation of Bone Lining Cells

    PubMed Central

    Turner, Russell T.; Iwaniec, Urszula T.; Wong, Carmen P.; Lindenmaier, Laurence B.; Wagner, Lindsay A.; Branscum, Adam J.; Menn, Scott A.; Taylor, James; Zhang, Ye; Wu, Honglu; Sibonga, Jean D.

    2014-01-01

    The present studies investigated the cellular mechanisms for the detrimental effects of high dose whole body γ-irradiation on bone. In addition, radioadaptation and bone marrow transplantation were assessed as interventions to mitigate the skeletal complications of irradiation. Increased trabecular thickness and separation and reduced fractional cancellous bone volume, connectivity density, and trabecular number were detected in proximal tibia and lumbar vertebra 14 days following γ-irradiation with 6 Gy. To establish the cellular mechanism for the architectural changes, vertebrae were analyzed by histomorphometry 1, 3, and 14 days following irradiation. Marrow cell density decreased within 1 day (67% reduction, p<0.0001), reached a minimum value after 3 days (86% reduction, p<0.0001), and partially rebounded by 14 days (30% reduction, p=0.0025) following irradiation. In contrast, osteoblast-lined bone perimeter was increased by 290% (1 day, p=0.04), 1230% (3 days, p<0.0001), and 530% (14 days, p=0.003), respectively. There was a strong association between radiation-induced marrow cell death and activation of bone lining cells to express the osteoblast phenotype (Pearson correlation −0.85, p<0.0001). An increase (p=0.004) in osteoclast-lined bone perimeter was also detected with irradiation. A priming dose of γ-radiation (0.5 mGy), previously shown to reduce mortality, had minimal effect on the cellular responses to radiation and did not prevent detrimental changes in bone architecture. Bone marrow transplantation normalized marrow cell density, bone turnover, and most indices of bone architecture following irradiation. In summary, radiation-induced death of marrow cells is associated with 1) a transient increase in bone formation due, at least in part, to activation of bone lining cells, and 2) an increase in bone resorption due to increased osteoclast perimeter. Bone marrow transplantation is effective in mitigating the detrimental effects of acute exposure

  8. Acute high-dose X-radiation-induced genomic changes in A549 cells.

    PubMed

    Muradyan, A; Gilbertz, K; Stabentheiner, S; Klause, S; Madle, H; Meineke, V; Ullmann, R; Scherthan, H

    2011-06-01

    Accidents with ionizing radiation often involve single, acute high-dose exposures that can lead to acute radiation syndrome and late effects such as carcinogenesis. To study such effects at the cellular level, we investigated acute ionizing radiation-induced chromosomal aberrations in A549 adenocarcinoma cells at the genome-wide level by exposing the cells to an acute dose of 6 Gy 240 kV X rays. One sham-irradiated clone and four surviving irradiated clones were recovered by minimal dilution and further expanded and analyzed by chromosome painting and tiling-path array CGH, with the nonirradiated clone 0 serving as the control. Acute X-ray exposure induced specific translocations and changes in modal chromosome number in the four irradiated clones. Array CGH disclosed unique and recurrent genomic changes, predominantly losses, and revealed that the fragile sites FRA3B and FRA16D were preferential regions of genomic alterations in all irradiated clones, which is likely related to radioresistant S-phase progression and genomic stress. Furthermore, clone 4 displayed an increased radiosensitivity at doses >5 Gy. Pairwise comparisons of the gene expression patterns of all irradiated clones to the sham-irradiated clone 0 revealed an enrichment of the Gene Ontology term "M Phase" (P = 6.2 × 10(-7)) in the set of differentially expressed genes of clone 4 but not in those of clones 1-3. Ionizing radiation-induced genomic changes and fragile site expression highlight the capacity of a single acute radiation exposure to affect the genome of exposed cells by inflicting genomic stress.

  9. Implementation and modification of a three-dimensional radiation stress formulation for surf zone and rip-current applications

    USGS Publications Warehouse

    Kumar, N.; Voulgaris, G.; Warner, J.C.

    2011-01-01

    Regional Ocean Modeling System (ROMS v 3.0), a three-dimensional numerical ocean model, was previously enhanced for shallow water applications by including wave-induced radiation stress forcing provided through coupling to wave propagation models (SWAN, REF/DIF). This enhancement made it suitable for surf zone applications as demonstrated using examples of obliquely incident waves on a planar beach and rip current formation in longshore bar trough morphology (Haas and Warner, 2009). In this contribution, we present an update to the coupled model which implements a wave roller model and also a modified method of the radiation stress term based on Mellor (2008, 2011a,b,in press) that includes a vertical distribution which better simulates non-conservative (i.e., wave breaking) processes and appears to be more appropriate for sigma coordinates in very shallow waters where wave breaking conditions dominate. The improvements of the modified model are shown through simulations of several cases that include: (a) obliquely incident spectral waves on a planar beach; (b) obliquely incident spectral waves on a natural barred beach (DUCK'94 experiment); (c) alongshore variable offshore wave forcing on a planar beach; (d) alongshore varying bathymetry with constant offshore wave forcing; and (e) nearshore barred morphology with rip-channels. Quantitative and qualitative comparisons to previous analytical, numerical, laboratory studies and field measurements show that the modified model replicates surf zone recirculation patterns (onshore drift at the surface and undertow at the bottom) more accurately than previous formulations based on radiation stress (Haas and Warner, 2009). The results of the model and test cases are further explored for identifying the forces operating in rip current development and the potential implication for sediment transport and rip channel development. Also, model analysis showed that rip current strength is higher when waves approach at angles of 5

  10. Black Carbon Simulations Using a Size- and Mixing-State-Resolved Three-Dimensional Model: Radiative Effects and Their Uncertainties

    NASA Astrophysics Data System (ADS)

    Matsui, H.

    2016-12-01

    This study quantifies how uncertainties in the size distribution and mixing state parameters of black carbon (BC) emissions translate into the uncertainties in BC radiative effects by using a particle-size- and mixing-state-resolved three-dimensional model, the Weather Research and Forecasting model with chemistry (WRF-chem) with the Aerosol Two-dimensional bin module for foRmation and Aging Simulation (ATRAS) and the Model for Simulating Aerosol Interactions and Chemistry (MOSAIC). The WRF-chem/ATRAS-MOSAIC model can explicitly calculate BC processes in the atmosphere, such as BC aging due to condensation and coagulation and the resulting enhancement of absorption and cloud condensation nuclei activity, with 12 size and 10 BC mixing state bins (128 bins in total). Fifteen model simulations perturbing the emission parameters within their uncertainties are conducted over East Asia (spring 2009) to understand which parameters and processes are important and which are associated with the uncertainty in evaluating BC radiative effects. The simulations reveal a large variability (uncertainty) of BC optical and radiative variables over the East Asian region (the variability is 58-99%), which corresponds to ranges of BC radiative effect of 1.6-2.8 W m-2 at the top of the atmosphere and from -5.2 to -2.1 W m-2 at the surface over East Asia. BC optical and radiative variables are 3 to 5 times sensitive to the size and the mixing state in emissions than BC mass concentrations (the variability is 20%). The two main causes of the difference in sensitivity are the reduction of the variability of BC mass concentrations by coagulation and the enhancement of the variability of BC absorption by resolving BC mixing state. These complicated responses of aerosol processes can be calculated for the first time using a detailed aerosol model such as ATRAS. The results suggest that the following two points are important in the estimation of BC radiative effects: (1) reduction of the

  11. Skin wound trauma, following high-dose radiation exposure, amplifies and prolongs skeletal tissue loss.

    PubMed

    Swift, Joshua M; Swift, Sibyl N; Smith, Joan T; Kiang, Juliann G; Allen, Matthew R

    2015-12-01

    The present study investigated the detrimental effects of non-lethal, high-dose (whole body) γ-irradiation on bone, and the impact that radiation combined with skin trauma (i.e. combined injury) has on long-term skeletal tissue health. Recovery of bone after an acute dose of radiation (RI; 8 Gy), skin wounding (15-20% of total body skin surface), or combined injury (RI+Wound; CI) was determined 3, 7, 30, and 120 days post-irradiation in female B6D2F1 mice and compared to non-irradiated mice (SHAM) at each time-point. CI mice demonstrated long-term (day 120) elevations in serum TRAP 5b (osteoclast number) and sclerostin (bone formation inhibitor), and suppression of osteocalcin levels through 30 days as compared to SHAM (p<0.05). Radiation-induced reductions in distal femur trabecular bone volume fraction and trabecular number through 120 days post-exposure were significantly greater than non-irradiated mice (p<0.05) and were exacerbated in CI mice by day 30 (p<0.05). Negative alterations in trabecular bone microarchitecture were coupled with extended reductions in cancellous bone formation rate in both RI and CI mice as compared to Sham (p<0.05). Increased osteoclast surface in CI animals was observed for 3 days after irradiation and remained elevated through 120 days (p<0.01). These results demonstrate a long-term, exacerbated response of bone to radiation when coupled with non-lethal wound trauma. Changes in cancellous bone after combined trauma were derived from extended reductions in osteoblast-driven bone formation and increases in osteoclast activity.

  12. The effect of high dose rate transient gamma radiation on high-energy optical fibers

    NASA Astrophysics Data System (ADS)

    Akinci, A.; Bowden, M. D.; Cheeseman, M. C.; Knowles, S. L.; Meister, D. C.; Pecak, S. N.; Simmons Potter, K.

    2009-08-01

    High power laser systems have a number of uses in a variety of scientific and defense applications, for example laser induced breakdown spectroscopy (LIBS) or laser-triggered switches. In general, high power optical fibers are used to deliver the laser energy from the source to the target in preference to free space beams. In certain cases, such as nuclear reactors, these optical systems are expected to operate in ionizing radiation environments. In this paper, a variety of modern, currently available commercial off-the-shelf (COTS) optical fiber designs have been assessed for successful operation in the transient gamma radiation environment produced by the HERMES III accelerator at Sandia National Laboratories, USA. The performance of these fibers was evaluated for high (~1 MW) and low (<1 W) optical power transmission during high dose rate, high total dose gamma irradiation. A significant reduction in low optical power transmission to 32% of maximum was observed for low OH- content fibers, and 35% of maximum for high OH- fibers. The high OH- fibers were observed to recover to 80% transmission within 1 μs and 100% transmission within 1 ms. High optical power transmission losses followed generally similar trends to the low optical power transmission losses, though evidence for an optical power dependent recovery was observed. For 10-20 mJ, 15 ns laser pulses, around 46% was transmitted coincident with the radiation pulse, recovering to 70% transmission within 40 ns of the radiation pulse. All fibers were observed to completely recover within a few minutes for high optical powers. High optical power densities in excess of 1 GW/cm2 were successfully transmitted during the period of highest loss without any observed damage to the optical fibers.

  13. High-resolution three-dimensional visualization of the rat spinal cord microvasculature by synchrotron radiation micro-CT

    SciTech Connect

    Hu, Jianzhong; Cao, Yong; Wu, Tianding; Li, Dongzhe; Lu, Hongbin

    2014-10-15

    Purpose: Understanding the three-dimensional (3D) morphology of the spinal cord microvasculature has been limited by the lack of an effective high-resolution imaging technique. In this study, synchrotron radiation microcomputed tomography (SRµCT), a novel imaging technique based on absorption imaging, was evaluated with regard to the detection of the 3D morphology of the rat spinal cord microvasculature. Methods: Ten Sprague-Dawley rats were used in this ex vivo study. After contrast agent perfusion, their spinal cords were isolated and scanned using conventional x-rays, conventional micro-CT (CµCT), and SRµCT. Results: Based on contrast agent perfusion, the microvasculature of the rat spinal cord was clearly visualized for the first time ex vivo in 3D by means of SRµCT scanning. Compared to conventional imaging techniques, SRµCT achieved higher resolution 3D vascular imaging, with the smallest vessel that could be distinguished approximately 7.4 μm in diameter. Additionally, a 3D pseudocolored image of the spinal cord microvasculature was generated in a single session of SRµCT imaging, which was conducive to detailed observation of the vessel morphology. Conclusions: The results of this study indicated that SRµCT scanning could provide higher resolution images of the vascular network of the spinal cord. This modality also has the potential to serve as a powerful imaging tool for the investigation of morphology changes in the 3D angioarchitecture of the neurovasculature in preclinical research.

  14. Three-dimensional evaluation of the compression and recovery behavior in a flexible graphite sheet by synchrotron radiation microtomography

    SciTech Connect

    Kobayashi, M.; Toda, H.; Takeuchi, A.; Uesugi, K.; Suzuki, Y.

    2012-07-15

    The compression and unloading behavior of flexible graphite sheets was investigated using synchrotron radiation microtomography with 1 {mu}m voxel size. The recovery ratio of the flexible graphite sheet was measured accurately by in-situ observation. The three-dimensional strain distribution in the interior of the specimen was obtained using the microstructural tracking method. The inner strain distribution with micrometer scale indicated inhomogeneous deformation. The microstructural tracking analysis revealed that deformation units exist in the flexible graphite sheet. The units seem to deform, affecting the neighboring units with each other. The units had a similar size and shape with compacted exfoliated graphite worms that constitute the flexible graphite sheet. Microscopic deformations during compression and unloading are surely affected by the microstructure of the sheet. Highlights: Black-Right-Pointing-Pointer The compression and recovery behavior was investigated using microtomography. Black-Right-Pointing-Pointer The tracking analysis revealed that deformation units exist in the specimen. Black-Right-Pointing-Pointer Each unit deforms in relation to the neighboring unit.

  15. General-Relativistic Three-Dimensional Multi-group Neutrino Radiation-Hydrodynamics Simulations of Core-Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Roberts, Luke F.; Ott, Christian D.; Haas, Roland; O'Connor, Evan P.; Diener, Peter; Schnetter, Erik

    2016-11-01

    We report on a set of long-term general-relativistic three-dimensional (3D) multi-group (energy-dependent) neutrino radiation-hydrodynamics simulations of core-collapse supernovae. We employ a full 3D two-moment scheme with the local M1 closure, three neutrino species, and 12 energy groups per species. With this, we follow the post-core-bounce evolution of the core of a nonrotating 27 - {M}⊙ progenitor in full unconstrained 3D and in octant symmetry for ≳380 ms. We find the development of an asymmetric runaway explosion in our unconstrained simulation. We test the resolution dependence of our results and, in agreement with previous work, find that low resolution artificially aids explosion and leads to an earlier runaway expansion of the shock. At low resolution, the octant and full 3D dynamics are qualitatively very similar, but at high resolution, only the full 3D simulation exhibits the onset of explosion.

  16. Three-dimensional Effects and Shortwave Cloud Radiative Forcing Associated with Shallow Cumuli Over Central North America

    SciTech Connect

    Berg, Larry K.; Kassianov, Evgueni I.; Long, Charles N.; Mills, Jr., David

    2009-09-30

    Shallow cumuli are ubiquitous over large areas of the globe, including both the interior of continents and the trade wind regions over the oceans. Measurements made at the Atmospheric Radiation Measurement (ARM) Climate Research Facility, located in central North America, provide a unique long-term data set that can be used to investigate the influence that these clouds have on the shortwave surface energy budget at a continental location. Using data collected for the summers of 2000 through 2007, inclusive, over 900 hours with fair-weather cumuli were identified using data from a Total Sky Imager, cloud-radar and lidar. Data from a suite of surface radiometers was used to determine the shortwave forcing. This analysis estimates the three-dimensional effects of shallow cumuli by examining the occurrences of both positive and negative shortwave forcing. We show that the average surface shortwave forcing is approximately -45.5 W m-2. When the data are adjusted to account for periods without shallow clouds, the shortwave forcing over the entire summer (defined as May through August) are reduced in magnitude, with forcings of -2.1 W m-2.

  17. Three-dimensional numerical simulation of internal tides that radiated from the Luzon Strait into the Western Pacific

    NASA Astrophysics Data System (ADS)

    Liu, Kun; Xu, Zhenhua; Yin, Baoshu

    2017-01-01

    Recent satellite altimeter observations have indicated that internal tides (ITs) from the Luzon Strait (LS) propagate more than 2 500 km into the Western Pacific (WP). This study used a high-resolution three-dimensional numerical model to reproduce and examine the ITs radiation process. The propagation of diurnal and semidiurnal ITs showed different patterns and variations. Diurnal ITs with lower frequency were affected more by the earth's rotation and they were bent more toward the equator than semidiurnal ITs. ITs phase speeds are functions of latitude and diurnal ITs showed greater distinctions of phase speeds during propagation. For M2 ITs, the wavelength remained nearly unchanged but the beam width increased significantly during propagation away from the LS. For diurnal ITs (K1 and O1), the wavelength decreased noticeably with latitude, while the beam width varied little during propagation because of blocking by land. Baroclinic energy was also examined as a complement to satellite results reported by Zhao (2014). The magnitude of the generated baroclinic energy flux reduced remarkably within 300 km from the generation site but it then decayed slowly when propagating into abyssal sea. Baroclinic energy of diurnal ITs was found to dissipate at a slower rate than semidiurnal ITs along the main propagation path in the WP.

  18. High doses of gamma radiation suppress allergic effect induced by food lectin

    NASA Astrophysics Data System (ADS)

    Vaz, Antônio F. M.; Souza, Marthyna P.; Vieira, Leucio D.; Aguiar, Jaciana S.; Silva, Teresinha G.; Medeiros, Paloma L.; Melo, Ana M. M. A.; Silva-Lucca, Rosemeire A.; Santana, Lucimeire A.; Oliva, Maria L. V.; Perez, Katia R.; Cuccovia, Iolanda M.; Coelho, Luana C. B. B.; Correia, Maria T. S.

    2013-04-01

    One of the most promising areas for the development of functional foods lies in the development of effective methods to reduce or eliminate food allergenicity, but few reports have summarized information concerning the progress made with food irradiation. In this study, we investigated the relationship between allergenicity and molecular structure of a food allergen after gamma irradiation and evaluate the profile of the allergic response to irradiated allergens. Cramoll, a lectin isolated from a bean and used as a food allergen, was irradiated and the possible structural changes were accompanied by spectrofluorimetry, circular dichroism and microcalorimetry. Subsequently, sensitized animals subjected to intragastric administration of non-irradiated and irradiated Cramoll were treated for 7 days. Then, body weight, leukocytes, cytokine profiles and histological parameters were also determined. Cramoll showed complete inhibition of intrinsic activity after high radiation doses. Changes in fluorescence and CD spectra with a simultaneous collapse of the tertiary structure followed by a pronounced decrease of native secondary structure were observed after irradiation. After oral challenge, sensitized mice demonstrate an association between Cramoll intake, body weight loss, eosinophilia, lymphocytic infiltrate in the gut and Eotaxin secretion. Irradiation significantly reduces, according to the dose, the effects observed by non-irradiated food allergens. We confirm that high-dose radiation may render protein food allergens innocuous by irreversibly compromising their molecular structure.

  19. Three Dimensional Fusion CT Decreases Radiation Exposure, Procedure Time and Contrast Use during Fenestrated Endovascular Aortic Repair

    PubMed Central

    McNally, Michael M.; Scali, Salvatore T.; Feezor, Robert J.; Neal, Daniel; Huber, Thomas S.; Beck, Adam W.

    2014-01-01

    Objectives Endovascular surgery has revolutionized the treatment of aortic aneurysms; however these improvements have come at the cost of increased radiation and contrast exposure, particularly for more complex procedures. Three dimensional (3D) fusion computed tomographic (CT) imaging is a new technology that may facilitate these repairs. The purpose of this analysis was to determine the impact of utilizing intraoperative 3D fusion CT on performance of fenestrated endovascular aortic repair. Methods A review of our institutional database was performed to identify patients undergoing fenestrated/branched endovascular aortic repair (FEVAR). Subjects treated using 3D fusion CT were compared to patients treated in the immediate 12-month period prior to implementation of this technology when procedures were performed in a standard hybrid operating room without CT fusion capabilities. Primary endpoints included patient radiation exposure (air kerma area product: milliGray; mGy*cm2), fluoroscopy time (minutes; min), contrast usage (mL) and procedure time (min). Patients were grouped by number of aortic graft fenestrations revascularized with a stentgraft and operative outcomes were compared. Results A total of 72 patients (N = 41 before vs. N = 31 after 3D fusion CT implementation) underwent FEVAR from September 2012 through March 2014. For 2-vessel fenestrated endografts, there was a significant decrease in radiation exposure (3400±1900 vs. 1380±520 mGy*cm2; P=.001), fluoroscopy time (63±29 vs. 41±11min; P=.02), and contrast usage (69±16 vs. 26±8 mL; P=.0002) with intraoperative 3D fusion CT. Similarly, for combined 3 and 4-vessel FEVAR, significantly decreased radiation exposure (5400±2225 vs. 2700±1400 mGy*cm2; P<.0001), fluoroscopy time (89±36 vs 6±21min; P=.02), contrast usage (90±25 vs. 39±17mL; P<.0001), as well as procedure time (330±100 vs. 230±50min; P=.002) was noted. Estimated blood loss was significantly less (P<.0001) and length of stay had a

  20. Three-dimensional radiation-hydrodynamics calculations of the envelopes of young planets embedded in protoplanetary disks

    SciTech Connect

    D'Angelo, Gennaro; Bodenheimer, Peter E-mail: peter@ucolick.org

    2013-11-20

    We perform global three-dimensional (3D) radiation-hydrodynamics calculations of the envelopes surrounding young planetary cores of 5, 10, and 15 Earth masses, located in a protoplanetary disk at 5 and 10 AU from a solar-mass star. We apply a nested-grid technique to resolve the thermodynamics of the disk at the orbital-radius length scale and that of the envelope at the core-radius length scale. The gas is modeled as a solar mixture of molecular and atomic hydrogen, helium, and their ions. The equation of state accounts for both gas and radiation, and gas energy includes contributions from rotational and vibrational states of molecular hydrogen and from ionization of atomic species. Dust opacities are computed from first principles, applying the full Mie theory. One-dimensional (1D) calculations of planet formation are used to supplement the 3D calculations by providing energy deposition rates in the envelope due to solids accretion. We compare 1D and 3D envelopes and find that masses and gas accretion rates agree within factors of 2, and so do envelope temperatures. The trajectories of passive tracers are used to define the size of 3D envelopes, resulting in radii much smaller than the Hill radius and smaller than the Bondi radius. The moments of inertia and angular momentum of the envelopes are determined and the rotation rates are derived from the rigid-body approximation, resulting in slow bulk rotation. We find that the polar flattening is ≲ 0.05. The dynamics of the accretion flow are examined by tracking the motion of tracers that move into the envelope. The anisotropy of this flow is characterized in terms of both its origin and impact site at the envelope surface. Gas merges with the envelope preferentially at mid- to high latitudes.

  1. Identifying cell and molecular stress after radiation in a three-dimensional (3-D) model of oral mucositis.

    PubMed

    Lambros, Maria Polikandritou; Parsa, Cyrus; Mulamalla, HariChandana; Orlando, Robert; Lau, Bernard; Huang, Ying; Pon, Doreen; Chow, Moses

    2011-02-04

    Mucositis is a debilitating adverse effect of chemotherapy and radiation treatment. It is important to develop a simple and reliable in vitro model, which can routinely be used to screen new drugs for prevention and treatment of mucositis. Furthermore, identifying cell and molecular stresses especially in the initiation phase of mucositis in this model will help towards this end. We evaluated a three-dimensional (3-D) human oral cell culture that consisted of oral keratinocytes and fibroblasts as a model of oral mucositis. The 3-D cell culture model was irradiated with 12 or 2 Gy. Six hours after the irradiation we evaluated microscopic sections of the cell culture for evidence of morphologic changes including apoptosis. We used microarrays to compare the expression of several genes from the irradiated tissue with identical genes from tissue that was not irradiated. We found that irradiation with 12 Gy induced significant histopathologic effects including cellular apoptosis. Irradiation significantly affected the expression of several genes of the NF-kB pathway and several inflammatory cytokines, such as IL-1B, 1L-8, NF-kB1, and FOS compared to tissue that was not irradiated. We identified significant upregulation of several genes that belong to damage-associated molecular patterns (DAMPs) such as HMB1, S100A13, SA10014, and SA10016 in the 3-D tissues that received 12 Gy but not in tissues that received 2 Gy. In conclusion, this model quantifies radiation damage and this is an important first step towards the development 3-D tissue as a screening tool.

  2. Formation of Overheated Regions and Truncated Disks around Black Holes: Three-dimensional General Relativistic Radiation-magnetohydrodynamics Simulations

    NASA Astrophysics Data System (ADS)

    Takahashi, Hiroyuki R.; Ohsuga, Ken; Kawashima, Tomohisa; Sekiguchi, Yuichiro

    2016-07-01

    Using three-dimensional general relativistic radiation-magnetohydrodynamics simulations of accretion flows around stellar mass black holes, we report that the relatively cold disk (≳ {10}7 {{K}}) is truncated near the black hole. Hot and less dense regions, of which the gas temperature is ≳ {10}9 {{K}} and more than 10 times higher than the radiation temperature (overheated regions), appear within the truncation radius. The overheated regions also appear above as well as below the disk, sandwiching the cold disk, leading to the effective Compton upscattering. The truncation radius is ˜ 30{r}{{g}} for \\dot{M}˜ {L}{{Edd}}/{c}2, where {r}{{g}},\\dot{M},{L}{Edd},c are the gravitational radius, mass accretion rate, Eddington luminosity, and light speed, respectively. Our results are consistent with observations of a very high state, whereby the truncated disk is thought to be embedded in the hot rarefied regions. The truncation radius shifts inward to ˜ 10{r}{{g}} with increasing mass accretion rate \\dot{M}˜ 100{L}{{Edd}}/{c}2, which is very close to an innermost stable circular orbit. This model corresponds to the slim disk state observed in ultraluminous X-ray sources. Although the overheated regions shrink if the Compton cooling effectively reduces the gas temperature, the sandwich structure does not disappear at the range of \\dot{M}≲ 100{L}{{Edd}}/{c}2. Our simulations also reveal that the gas temperature in the overheated regions depends on black hole spin, which would be due to efficient energy transport from black hole to disks through the Poynting flux, resulting in gas heating.

  3. Three-Dimensional, Finite-Difference, Time-Domain Modeling of Local Volcano Infrasound Radiation Using GPU

    NASA Astrophysics Data System (ADS)

    Kim, K.; Lees, J. M.

    2013-12-01

    Since volcano infrasound is a direct measure of atmospheric pressure fluctuation near open-vent activity, it can provide important constraints on eruption source parameters including the volume of gas released and eruption velocity. Local infrasound data (<15 Km) have been used to quantify and characterize acoustic sources of volcanic eruptions since they are relatively less affected by atmospheric velocity structures in the near field. The interaction of volcano infrasound sources and complex topography near the volcanic edifice, however, has not been fully explored. Infrasound observations from world-wide volcanoes and two-dimensional numerical modeling of infrasound radiation in the vicinity of the crater suggest a strong distortion of the wavefield by local topography [Kim and Lees, GRL, 2011]. To get a complete picture of these effects, however, full three-dimensional modeling is required. We have developed a new, accelerated, 3D finite-difference time-domain program using GPU (Grpahic Processing Units) to simulate local infrasound propagation near volcanoes, while taking into account complex topography, local wind distortion, and atmospheric sound velocity structures. While CPU-based 3D FDTD method requires a prohibitive amount of computational resources, GPU-based algorithms significantly reduce the computational time of infrasound modeling, making parallel processing practical even on a desktop computer. In these simulations we provide a comprehensive solution of volcano infrasound radiation assuming different acoustic sources and real volcano topography. We illustrate the interaction of local vent topography and difference acoustic sources and how they combine to affect the infrasound wavefield. By removing topographic effects from local infrasound observation we can begin to quantitatively model acoustic sources and finally establish the partitioning of energy, at the vent, between the acoustic and seismic wavefields.

  4. Optically erasable samarium-doped fluorophosphate glasses for high-dose measurements in microbeam radiation therapy

    NASA Astrophysics Data System (ADS)

    Morrell, B.; Okada, G.; Vahedi, S.; Koughia, C.; Edgar, A.; Varoy, C.; Belev, G.; Wysokinski, T.; Chapman, D.; Sammynaiken, R.; Kasap, S. O.

    2014-02-01

    Previous work has demonstrated that fluorophosphate (FP) glasses doped with trivalent samarium (Sm3+) can be used as a dosimetric detector in microbeam radiation therapy (MRT) to measure high radiation doses and large dose variations with a resolution in the micrometer range. The present work addresses the use of intense optical radiation at 405 nm to erase the recorded dose information in Sm3+-doped FP glass plates and examines the underlying physics. We have evaluated both the conversion and optical erasure of Sm3+-doped FP glasses using synchrotron-generated high-dose x-rays at the Canadian Light Source. The Sm-ion valency conversion is accompanied by the appearance of x-ray induced optical absorbance due to the trapping of holes and electrons into phosphorus-oxygen hole (POHC) and electron (POEC) capture centers. Nearly complete Sm2+ to Sm3+ reconversion (erasure) may be achieved by intense optical illumination. Combined analysis of absorbance and electron spin resonance measurements indicates that the optical illumination causes partial disappearance of the POHC and the appearance of new POEC. The suggested model for the observed phenomena is based on the release of electrons during the Sm2+ to Sm3+ reconversion process, the capture of these electrons by POHC (and hence their disappearance), or by PO groups, with the appearance of new and/or additional POEC. Optical erasure may be used as a practical means to erase the recorded data and permits the reuse of these Sm-doped FP glasses in monitoring dose in MRT.

  5. Optically erasable samarium-doped fluorophosphate glasses for high-dose measurements in microbeam radiation therapy

    SciTech Connect

    Morrell, B.; Okada, G.; Vahedi, S.; Koughia, C. Kasap, S. O.; Edgar, A.; Varoy, C.; Belev, G.; Wysokinski, T.; Chapman, D.; Sammynaiken, R.

    2014-02-14

    Previous work has demonstrated that fluorophosphate (FP) glasses doped with trivalent samarium (Sm{sup 3+}) can be used as a dosimetric detector in microbeam radiation therapy (MRT) to measure high radiation doses and large dose variations with a resolution in the micrometer range. The present work addresses the use of intense optical radiation at 405 nm to erase the recorded dose information in Sm{sup 3+}-doped FP glass plates and examines the underlying physics. We have evaluated both the conversion and optical erasure of Sm{sup 3+}-doped FP glasses using synchrotron-generated high-dose x-rays at the Canadian Light Source. The Sm-ion valency conversion is accompanied by the appearance of x-ray induced optical absorbance due to the trapping of holes and electrons into phosphorus-oxygen hole (POHC) and electron (POEC) capture centers. Nearly complete Sm{sup 2+} to Sm{sup 3+} reconversion (erasure) may be achieved by intense optical illumination. Combined analysis of absorbance and electron spin resonance measurements indicates that the optical illumination causes partial disappearance of the POHC and the appearance of new POEC. The suggested model for the observed phenomena is based on the release of electrons during the Sm{sup 2+} to Sm{sup 3+} reconversion process, the capture of these electrons by POHC (and hence their disappearance), or by PO groups, with the appearance of new and/or additional POEC. Optical erasure may be used as a practical means to erase the recorded data and permits the reuse of these Sm-doped FP glasses in monitoring dose in MRT.

  6. High-Dose-Rate Intraoperative Radiation Therapy for Recurrent Head-and-Neck Cancer

    SciTech Connect

    Perry, David J.; Chan, Kelvin; Wolden, Suzanne; Zelefsky, Michael J.; Chiu, Johnny; Cohen, Gilad; Zaider, Marco; Kraus, Dennis; Shah, Jatin; Lee, Nancy

    2010-03-15

    Purpose: To report the use of high-dose-rate intraoperative radiation therapy (HDR-IORT) for recurrent head-and-neck cancer (HNC) at a single institution. Methods and Materials: Between July 1998 and February 2007, 34 patients with recurrent HNC received 38 HDR-IORT treatments using a Harrison-Anderson-Mick applicator with Iridium-192. A single fraction (median, 15 Gy; range, 10-20 Gy) was delivered intraoperatively after surgical resection to the region considered at risk for close or positive margins. In all patients, the target region was previously treated with external beam radiation therapy (median dose, 63 Gy; range, 24-74 Gy). The 1- and 2-year estimates for in-field local progression-free survival (LPFS), locoregional progression-free survival (LRPFS), distant metastases-free survival (DMFS), and overall survival (OS) were calculated. Results: With a median follow-up for surviving patients of 23 months (range, 6-54 months), 8 patients (24%) are alive and without evidence of disease. The 1- and 2-year LPFS rates are 66% and 56%, respectively, with 13 (34%) in-field recurrences. The 1- and 2-year DMFS rates are 81% and 62%, respectively, with 10 patients (29%) developing distant failure. The 1- and 2-year OS rates are 73% and 55%, respectively, with a median time to OS of 24 months. Severe complications included cellulitis (5 patients), fistula or wound complications (3 patients), osteoradionecrosis (1 patient), and radiation-induced trigeminal neuralgia (1 patient). Conclusions: HDR-IORT has shown encouraging local control outcomes in patients with recurrent HNC with acceptable rates of treatment-related morbidity. Longer follow-up with a larger cohort of patients is needed to fully assess the benefit of this procedure.

  7. Estimation of canopy parameters for inhomogeneous vegetation canopies from reflectance data. III - TRIM: A model for radiative transfer in heterogeneous three-dimensional canopies

    NASA Technical Reports Server (NTRS)

    Goel, Narendra S.; Grier, Toby

    1988-01-01

    A model for radiative transfer in heterogeneous three-dimensional canopies such as those found in forests is proposed. Its use in estimating important biophysical variables such as leaf area index and canopy architecture from bidirectional canopy reflectance data is discussed. The model and its use in estimating canopy parameters through its inversion are validated with measured canopy reflectance data for corn canopies.

  8. THREE-DIMENSIONAL RADIATIVE TRANSFER CALCULATIONS OF RADIATION FEEDBACK FROM MASSIVE BLACK HOLES: OUTFLOW OF MASS FROM THE DUSTY 'TORUS'

    SciTech Connect

    Roth, Nathaniel; Kasen, Daniel; Quataert, Eliot; Hopkins, Philip F.

    2012-11-01

    Observational and theoretical arguments suggest that the momentum carried in mass outflows from active galactic nuclei (AGNs) can reach several times L/c, corresponding to outflow rates of hundreds of solar masses per year. Radiation pressure on resonant absorption lines alone may not be sufficient to provide this momentum deposition, and the transfer of reprocessed IR radiation in dusty nuclear gas has been postulated to provide the extra enhancement. The efficacy of this mechanism, however, will be sensitive to multi-dimensional effects such as the tendency for the reprocessed radiation to preferentially escape along sightlines of lower column density. We use Monte Carlo radiative transfer calculations to determine the radiation force on dusty gas residing within approximately 30 parsecs from an accreting supermassive black hole. We calculate the net rate of momentum deposition in the surrounding gas and estimate the mass-loss rate in the resulting outflow as a function of solid angle for different black hole luminosities, sightline-averaged column densities, clumping parameters, and opening angles of the dusty gas. We find that these dust-driven winds carry momentum fluxes of 1-5 times L/c and correspond to mass-loss rates of 10-100 M {sub Sun} per year for a 10{sup 8} M {sub Sun} black hole radiating at or near its Eddington limit. These results help to explain the origin of high velocity molecular and atomic outflows in local ultraluminous infrared galaxies and can inform numerical simulations of galaxy evolution including AGN feedback.

  9. Adaptive Iterative Dose Reduction Using Three Dimensional Processing (AIDR3D) Improves Chest CT Image Quality and Reduces Radiation Exposure

    PubMed Central

    Yamashiro, Tsuneo; Miyara, Tetsuhiro; Honda, Osamu; Kamiya, Hisashi; Murata, Kiyoshi; Ohno, Yoshiharu; Tomiyama, Noriyuki; Moriya, Hiroshi; Koyama, Mitsuhiro; Noma, Satoshi; Kamiya, Ayano; Tanaka, Yuko; Murayama, Sadayuki

    2014-01-01

    Objective To assess the advantages of Adaptive Iterative Dose Reduction using Three Dimensional Processing (AIDR3D) for image quality improvement and dose reduction for chest computed tomography (CT). Methods Institutional Review Boards approved this study and informed consent was obtained. Eighty-eight subjects underwent chest CT at five institutions using identical scanners and protocols. During a single visit, each subject was scanned using different tube currents: 240, 120, and 60 mA. Scan data were converted to images using AIDR3D and a conventional reconstruction mode (without AIDR3D). Using a 5-point scale from 1 (non-diagnostic) to 5 (excellent), three blinded observers independently evaluated image quality for three lung zones, four patterns of lung disease (nodule/mass, emphysema, bronchiolitis, and diffuse lung disease), and three mediastinal measurements (small structure visibility, streak artifacts, and shoulder artifacts). Differences in these scores were assessed by Scheffe's test. Results At each tube current, scans using AIDR3D had higher scores than those without AIDR3D, which were significant for lung zones (p<0.0001) and all mediastinal measurements (p<0.01). For lung diseases, significant improvements with AIDR3D were frequently observed at 120 and 60 mA. Scans with AIDR3D at 120 mA had significantly higher scores than those without AIDR3D at 240 mA for lung zones and mediastinal streak artifacts (p<0.0001), and slightly higher or equal scores for all other measurements. Scans with AIDR3D at 60 mA were also judged superior or equivalent to those without AIDR3D at 120 mA. Conclusion For chest CT, AIDR3D provides better image quality and can reduce radiation exposure by 50%. PMID:25153797

  10. Simulated Space Radiation: Impact of Four Different Types of High-Dose Ionizing Radiation on the Lichen Xanthoria elegans.

    PubMed

    Brandt, Annette; Meeßen, Joachim; Jänicke, Reiner U; Raguse, Marina; Ott, Sieglinde

    2017-02-01

    This study addresses the viability of the lichen Xanthoria elegans after high-dose ionizing irradiation in the frame of the STARLIFE campaign. The first set of experiments was intended to resemble several types of galactic cosmic radiation (GCR) as present beyond the magnetic shield of Earth. In the second set of experiments, γ radiation up to 113 kGy was applied to test the limit of lichen resistance to ionizing radiation. Entire thalli of Xanthoria elegans were irradiated in the anhydrobiotic state. After STARLIFE 1, the metabolic activity of both symbionts was quantified by live/dead staining with confocal laser scanning microscopy. The photosynthetic activity was measured after the respective irradiation to assess the ability of the symbiotic green algae to restore photosynthesis after irradiation. The STARLIFE campaign complements the results of the LIFE experiments at the EXPOSE-E facility on the International Space Station by testing the model organism Xanthoria elegans on its resistance to hazardous radiation that might be accumulated during long-term space exposure. In addition, the photosynthetic activity of metabolically active lichen was investigated after X-ray irradiation up to 100 Gy (3.3 Gy/min). Since previous astrobiological experiments were mostly performed with anhydrobiotic lichen, these experiments will broaden our knowledge on the correlation of physiological state and astrobiological stressors. Key Words: Astrobiology-Extremotolerance-Gamma rays-Ionizing radiation-Lichens-Viability. Astrobiology 17, 136-144.

  11. Retrospective Biological Dosimetry at Low and High Doses of Radiation and Radioiodine Impact on Individual Susceptibility to Ionizing Radiation

    PubMed Central

    Cebulska-Wasilewska, Antonina; Krzysiek, Mateusz; Krajewska, Grażyna; Stępień, Artur; Krajewski, Paweł

    2017-01-01

    Iodine-131 (I-131) is often used in thyroid diagnostics and therapy. External and internal exposure to radioiodine can lead to molecular and cellular damage in peripheral blood lymphocytes. The aim of this study was to explore the influence of low and high doses of I-131 on susceptibility to ionizing radiation. Study groups consisted of 30 individuals free of thyroid diseases, 41 patients exposed diagnostically to low doses of I-131, and 37 hyperthyroidism patients exposed therapeutically to high doses. The standardized DNA repair competence assay was used to test the efficacy of the fast DNA repair process in G0 cells. Cytogenetic preparations were made in fresh blood samples before and after challenging cells in vitro with X-ray dose. The frequency of sister chromatid exchanges (SCE) and percentage of cells with significantly elevated numbers of SCE were used as cytogenetic biomarkers associated to homologous recombination and compared to reported earlier cytogenetic biomarkers of cancer risk. Strong individual variation in the biomarkers is observed in all investigated groups before and after challenging. Nevertheless, the efficiency of post challenging fast repair is significantly high in the patients exposed to diagnostic I-131 doses than in unexposed control group and linked to decreased cytogenetic damage. However, 5 weeks after administration of therapeutic doses, significant increases of unrepaired post challenging DNA and cytogenetic damages were observed indicating a health risk. Results also suggest that the appearance of cancers in immediate families might influence DNA repair differently in patients exposed to low than to high doses. PMID:28250909

  12. Identifying cell and molecular stress after radiation in a three-dimensional (3-D) model of oral mucositis

    SciTech Connect

    Lambros, Maria Polikandritou; Parsa, Cyrus; Mulamalla, HariChandana; Orlando, Robert; Lau, Bernard; Huang, Ying; Pon, Doreen; Chow, Moses

    2011-02-04

    Research highlights: {yields} We irradiated a 3-D human oral cell culture of keratinocytes and fibroblasts with 12 and 2 Gy. {yields} 6 h after irradiation the histopathology and apoptosis of the 3-D culture were evaluated. Microarrays were used to assess the gene expression in the irradiated 3-D tissue. {yields} 12 Gy induced significant histopathologic changes and cellular apoptosis. {yields} 12 Gy significantly affected genes of the NF-kB pathway, inflammatory cytokines and DAMPs. -- Abstract: Mucositis is a debilitating adverse effect of chemotherapy and radiation treatment. It is important to develop a simple and reliable in vitro model, which can routinely be used to screen new drugs for prevention and treatment of mucositis. Furthermore, identifying cell and molecular stresses especially in the initiation phase of mucositis in this model will help towards this end. We evaluated a three-dimensional (3-D) human oral cell culture that consisted of oral keratinocytes and fibroblasts as a model of oral mucositis. The 3-D cell culture model was irradiated with 12 or 2 Gy. Six hours after the irradiation we evaluated microscopic sections of the cell culture for evidence of morphologic changes including apoptosis. We used microarrays to compare the expression of several genes from the irradiated tissue with identical genes from tissue that was not irradiated. We found that irradiation with 12 Gy induced significant histopathologic effects including cellular apoptosis. Irradiation significantly affected the expression of several genes of the NF-kB pathway and several inflammatory cytokines, such as IL-1B, 1L-8, NF-kB1, and FOS compared to tissue that was not irradiated. We identified significant upregulation of several genes that belong to damage-associated molecular patterns (DAMPs) such as HMB1, S100A13, SA10014, and SA10016 in the 3-D tissues that received 12 Gy but not in tissues that received 2 Gy. In conclusion, this model quantifies radiation damage and this

  13. Intensity modulated radiation therapy (IMRT) is not superior to three-dimensional conformal radiation (3DCRT) for adjuvant gastric radiation: A matched pair analysis.

    PubMed

    Chopra, Supriya; Agarwal, Aditi; Engineer, Reena; Dora, Tapas; Thomas, Biji; Sonawone, Supriya; Paul, Siji N; Kannan, Sadhna; Patil, Prachi; Mehta, Shaesta; Shrivastava, Shyam Kishore

    2015-01-01

    To compare three-dimensional conformal radiation (3DCRT) and Intensity Modulated Radiation Therapy (IG-IMRT) for adjuvant gastric irradiation. From Jan 2010-Aug 2013, all patients undergoing 3DCRT and IG-IMRT were included. Systemic chemotherapy included 1 cycle before and 2 cycles after chemoradiation. Planning Target Volume (PTV) received 45 Gy/25 fractions/5 weeks with concurrent capcetabine 825 mg/m2 bid. Matched pair analysis was performed to evaluate imbalance in two cohorts if any. Common Toxicity Criteria for Adverse Event (CTCAE) vs 3.0 was used to record gastrointestinal (GI), hematological (HL), and renal toxicity during treatment and follow-up. Patterns of recurrence were documented. Mann-Whitney U test was used for statistical comparison. Of the 51 patients, 26 received 3DCRT and 25 IMRT. IMRT led to decrease in dose received by right and left kidney (12.4 Gy and 7.1 Gy and 29 Gy vs 8.2 Gy; P<0.001). Overall, 17.6% and 19.6% patients had grade II GI and HL toxicity and 3.9% and 5.9% had grade III GI and HL toxicity. No difference was observed in acute grade II-V GI or HL toxicity (11.5% vs 24%, P=0.07; 7.6% vs 20% P=0.20) or late GI, HL, or renal toxicity between 3DCRT and IMRT. No difference was observed in patterns of local relapse (11.5% vs 12%, P=0.14) or overall survival (39% and 38% (P=0.97)) between 3DCRT and IMRT. 3DCRT and IMRT are equivalent in terms of toxicity and local control.

  14. Simulated Space Radiation: Impact of Four Different Types of High-Dose Ionizing Radiation on the Lichen Xanthoria elegans

    NASA Astrophysics Data System (ADS)

    Brandt, Annette; Meeßen, Joachim; Jänicke, Reiner U.; Raguse, Marina; Ott, Sieglinde

    2017-02-01

    This study addresses the viability of the lichen Xanthoria elegans after high-dose ionizing irradiation in the frame of the STARLIFE campaign. The first set of experiments was intended to resemble several types of galactic cosmic radiation (GCR) as present beyond the magnetic shield of Earth. In the second set of experiments, γ radiation up to 113 kGy was applied to test the limit of lichen resistance to ionizing radiation. Entire thalli of Xanthoria elegans were irradiated in the anhydrobiotic state. After STARLIFE 1, the metabolic activity of both symbionts was quantified by live/dead staining with confocal laser scanning microscopy. The photosynthetic activity was measured after the respective irradiation to assess the ability of the symbiotic green algae to restore photosynthesis after irradiation. The STARLIFE campaign complements the results of the LIFE experiments at the EXPOSE-E facility on the International Space Station by testing the model organism Xanthoria elegans on its resistance to hazardous radiation that might be accumulated during long-term space exposure. In addition, the photosynthetic activity of metabolically active lichen was investigated after X-ray irradiation up to 100 Gy (3.3 Gy/min). Since previous astrobiological experiments were mostly performed with anhydrobiotic lichen, these experiments will broaden our knowledge on the correlation of physiological state and astrobiological stressors.

  15. Risk-adapted androgen deprivation and escalated three-dimensional conformal radiotherapy for prostate cancer: Does radiation dose influence outcome of patients treated with adjuvant androgen deprivation? A GICOR study.

    PubMed

    Zapatero, Almudena; Valcárcel, Francisco; Calvo, Felipe A; Algás, Rosa; Béjar, Amelia; Maldonado, Javier; Villá, Salvador

    2005-09-20

    Multicenter study conducted to determine the impact on biochemical control and survival of risk-adapted androgen deprivation (AD) combined with high-dose three-dimensional conformal radiotherapy (3DCRT) for prostate cancer. Results of biochemical control are reported. Between October 1999 and October 2001, 416 eligible patients with prostate cancer were assigned to one of three treatment groups according to their risk factors: 181 low-risk patients were treated with 3DCRT alone; 75 intermediate-risk patients were allocated to receive neoadjuvant AD (NAD) 4-6 months before and during 3DCRT; and 160 high-risk patients received NAD and adjuvant AD (AAD) 2 years after 3DCRT. Stratification was performed for treatment/risk group and total radiation dose. After a median follow-up of 36 months (range, 18 to 63 months), the actuarial biochemical disease-free survival (bDFS) at 5 years for all patients was 74%. The corresponding figures for low-risk, intermediate-risk, and high-risk disease were 80%, 73%, and 79%, respectively (P = .847). Univariate analysis showed that higher radiation dose was the only significant factor associated with bDFS for all patients (P = .0004). When stratified for treatment group, this benefit was evident for low-risk patients (P = .009) and, more interestingly, for high-risk patients treated with AAD. The 5-year bDFS for high-risk patients treated with AAD was 63% for radiation doses less than 72 Gy and 84% for those > or = 72 Gy (P = .003). The results of combined AAD plus high-dose 3DCRT are encouraging. To our knowledge, this is the first study showing an additional benefit of high-dose 3DCRT when combined with long-term AD for unfavorable disease.

  16. Vector theory of laser radiation scattering in an integrated optical waveguide with three-dimensional irregularities in the presence of noise

    SciTech Connect

    Egorov, Alexander A

    2004-08-31

    The vector theory of laser radiation scattering in an integrated optical waveguide with three-dimensional irregularities in the presence of noise is developed. The solution of the electrodynamic problem of laser radiation scattering in an irregular waveguide is obtained by the mode coupling technique using the perturbation theory. An approximate solution of the inhomogeneous three-dimensional wave equation is obtained by the method of Green's functions. The analytic formulas are derived for the radiation fields of propagating and evanescent modes. A physical interpretation is given for the obtained results. The role of noise as an independent depolarising factor (in addition to the classical one) during scattering of light is pointed out. (integrated optical waveguides and devices)

  17. Phase I Study of Concurrent High-Dose Three-Dimensional Conformal Radiotherapy With Chemotherapy Using Cisplatin and Vinorelbine for Unresectable Stage III Non-Small-Cell Lung Cancer

    SciTech Connect

    Sekine, Ikuo; Sumi, Minako; Ito, Yoshinori; Horinouchi, Hidehito; Nokihara, Hiroshi; Yamamoto, Noboru; Kunitoh, Hideo; Ohe, Yuichiro; Kubota, Kaoru; Tamura, Tomohide

    2012-02-01

    Purpose: To determine the maximum tolerated dose in concurrent three-dimensional conformal radiotherapy (3D-CRT) with chemotherapy for unresectable Stage III non-small-cell lung cancer (NSCLC). Patients and Methods: Eligible patients with unresectable Stage III NSCLC, age {>=}20 years, performance status 0-1, percent of volume of normal lung receiving 20 GY or more (V{sub 20}) {<=}30% received three to four cycles of cisplatin (80 mg/m{sup 2} Day 1) and vinorelbine (20 mg/m{sup 2} Days 1 and 8) repeated every 4 weeks. The doses of 3D-CRT were 66 Gy, 72 Gy, and 78 Gy at dose levels 1 to 3, respectively. Results: Of the 17, 16, and 24 patients assessed for eligibility, 13 (76%), 12 (75%), and 6 (25%) were enrolled at dose levels 1 to 3, respectively. The main reasons for exclusion were V{sub 20} >30% (n = 10) and overdose to the esophagus (n = 8) and brachial plexus (n = 2). There were 26 men and 5 women, with a median age of 60 years (range, 41-75). The full planned dose of radiotherapy could be administered to all the patients. Grade 3-4 neutropenia and febrile neutropenia were noted in 24 (77%) and 5 (16%) of the 31 patients, respectively. Grade 4 infection, Grade 3 esophagitis, and Grade 3 pulmonary toxicity were noted in 1 patient, 2 patients, and 1 patient, respectively. The dose-limiting toxicity was noted in 17% of the patients at each dose level. The median survival and 3-year and 4-year survival rates were 41.9 months, 72.3%, and 49.2%, respectively. Conclusions: 72 Gy was the maximum dose that could be achieved in most patients, given the predetermined normal tissue constraints.

  18. Genetic compensation of high dose radiation-induced damage in an anhydrobiotic insect

    NASA Astrophysics Data System (ADS)

    Gusev, Oleg; Nakahara, Yuichi; Sakashita, Tetsuya; Kikawada, Takahiro; Okuda, Takashi

    Anhydrobiotic larvae of African chironomid Polypedilum vanderplanki are known to show an extremely high tolerance against a range of stresses. The tolerance against various extreme environments exhibited by that insect might be due to being almost completely desiccated replacing water with trehalose, a state where little or no chemical reactions occur. From 2005 dried larvae of this insect are being used in a number of space experiments, both inside and outside of ISS as a model organism for estimation the limits of higher organisms' resistance to space environment stresses and long-term storage of the alive anhydrobiotic organisms during continues spaceflight. We have shown previously that both hydrated and dried larvae of Polypedilum vanderplanki have very higher tolerance against both highand low-linear energy transfer (LET), surviving after 7000Gy irradiation. It was suggested that the larvae would have effective DNA-reparation system in addition to artificial protection provided by glass-stage without water. In the present study we conducted analysis of stress-related gene expression in the larvae after 70-2000 Gy irradiations. Both DNA damage level and activity of DNA-reparation, anti-apoptotic and protein-damage related genes were analyzed. Direct visualization of DNA damage in the larvae fat body cells using Comet Assay showed that fragmented by radiation DNA is re-arranged within 76-98 hours after exposure. We found that massive overexpression of hsp and anti-oxidant genes occur in larvae entering anhydrobiosis , and provides refolding of proteins after rehydration. In the irradiated larvae overexpression of DNA-reparation enzymes anti-apoptotic genes was confirmed, suggesting that survival after high-dose irradiation is a result of combination of highly effective blocking of entering the apoptosis after severe DNA damage and DNA reparation.

  19. Effect of high dose natural ionizing radiation on the immune system of the exposed residents of Ramsar Town, Iran.

    PubMed

    Attar, Massoud; Molaie Kondolousy, Yaghob; Khansari, Nemat

    2007-06-01

    Iran is one of several countries that has regions of high dose natural ionizing radiation. Two well-known villages in the suburb of Ramsar Town in the Caspian Sea strip, Taleshmahaleh and Chaparsar, have background radiation that is 13 times higher than normal. This radiation is the result of Radium 226 and Radon gas both of which are highly water soluble. While people living in these regions do not suffer from any major health problems, we decided to study the their immune responses to infection and inflammation in order to determine if their habitat affects their immune defense mechanisms as a way of compensating for their exposure to high dose environmental ionizing radiation. Our results showed that the total serum antioxidant level in the exposed people was significantly lower than the individuals not exposed to high dose natural ionizing radiation. The exposed individuals also had higher lymphocyte-induced IL-4 and IL-10 production, and lower IL-2 and IFN-gamma production. In addition, neutrophil NBT, phagocytosis, and locomotion were higher in the exposed group. In contrast, lymphocyte proliferation in response to PHA was unaffected. We conclude that the immune system of individuals exposed to high dose ionizing radiation has adapted to its environment by shifting from a Type 1 to a Type 2 response to promote anti-inflammation. This may be because inflammatory Type 1 responses generate more free radicals than Type 2 responses, in addition to the free radicals generated as a result of high environmental radiation. Thus, the serum total antioxidant level in the exposed residents was lower than the unexposed group.

  20. Radiation safety protocol for high dose 131I therapy of thyroid carcinoma in patients on hemodialysis for chronic renal failure.

    PubMed

    Modarresifar, Homayoun; Almodovar, Samuel; Bass, William B; Ojha, Buddhiwardhan

    2007-02-01

    Iodine ablation therapy for thyroid cancer on patients receiving dialysis poses unique radiation safety challenges. Exposure to gamma and beta negative particles by the hemodialysis (HD) staff is a concern that has not been well studied. A 53-y-old male patient on HD for chronic renal failure was scheduled for 131I high dose therapy as treatment for thyroid papillary carcinoma. The patient was on HD every other day, prior to ablation. A high dose of 131I (3,607.5 MBq) was required. The patient was admitted for 131I therapy, and continued HD. Thyroid cancer ablation therapy was administered according to our institutional protocol. New radiation safety measures were developed and implemented in order to give the patient an optimal treatment dose, reduce radiation to the patient (critical organs and whole body), and to protect the HD personnel. This included placing two lead shields between the patient and the HD nurse, and HD monitoring by two alternating nurses to reduce their radiation exposure. Film badges were used to measure radiation exposure to the nursing staff. Dosimetry calculations were obtained to determine radiation absorbed doses by the optic lens, skin, and whole body. Quality control verification for this shielding arrangement proved to be effective in protecting the HD staff against gamma and beta negative radiation from recent 131I high dose therapy. Implementation of this model proved to be an effective and adequate radiation safety protocol for limiting radiation exposure to the HD staff. The patient was given 3607.5 MBq for optimal treatment after HD. Hemodialysis was repeated after approximately 48 and 96 h to remove excess 131I and reduce radiation to the patient.

  1. High-dose radiation-induced meningiomas. Report of five cases and critical review of the literature.

    PubMed

    Salvati, Maurizio; Caroli, Emanuela; Brogna, Cristian; Orlando, Epimenio Ramundo; Delfini, Roberto

    2003-01-01

    Radiotherapy is an important modality for the treatment of tumors and arteriovenous malformations affecting the central nervous system, even though several significant side effects have been described (radionecrosis, tumors, etc.). Meningiomas induced by high-dose radiation therapy are uncommon. In this study we describe five cases treated at our institute and review all previously published reports of meningioma occurring after high-dose radiotherapy. These tumors develop mainly in patients irradiated in childhood; their incidence peaks in the second decade of life, there is a predominance in females and a high frequency of malignant forms. Although rare, meningiomas may represent a late complication of radiation treatment. The behavior of the radiation-induced variety of meningioma seems to differ from that of its "spontaneous" counterpart. The use of radiotherapy should be carefully evaluated for relatively benign or congenital lesions which generally affect young patients with a long life expectancy.

  2. Monte Carlo Study of Radiation Dose Enhancement by Gadolinium in Megavoltage and High Dose Rate Radiotherapy

    PubMed Central

    Zhang, Daniel G.; Feygelman, Vladimir; Moros, Eduardo G.; Latifi, Kujtim; Zhang, Geoffrey G.

    2014-01-01

    MRI is often used in tumor localization for radiotherapy treatment planning, with gadolinium (Gd)-containing materials often introduced as a contrast agent. Motexafin gadolinium is a novel radiosensitizer currently being studied in clinical trials. The nanoparticle technologies can target tumors with high concentration of high-Z materials. This Monte Carlo study is the first detailed quantitative investigation of high-Z material Gd-induced dose enhancement in megavoltage external beam photon therapy. BEAMnrc, a radiotherapy Monte Carlo simulation package, was used to calculate dose enhancement as a function of Gd concentration. Published phase space files for the TrueBeam flattening filter free (FFF) and conventional flattened 6MV photon beams were used. High dose rate (HDR) brachytherapy with Ir-192 source was also investigated as a reference. The energy spectra difference caused a dose enhancement difference between the two beams. Since the Ir-192 photons have lower energy yet, the photoelectric effect in the presence of Gd leads to even higher dose enhancement in HDR. At depth of 1.8 cm, the percent mean dose enhancement for the FFF beam was 0.38±0.12, 1.39±0.21, 2.51±0.34, 3.59±0.26, and 4.59±0.34 for Gd concentrations of 1, 5, 10, 15, and 20 mg/mL, respectively. The corresponding values for the flattened beam were 0.09±0.14, 0.50±0.28, 1.19±0.29, 1.68±0.39, and 2.34±0.24. For Ir-192 with direct contact, the enhanced were 0.50±0.14, 2.79±0.17, 5.49±0.12, 8.19±0.14, and 10.80±0.13. Gd-containing materials used in MRI as contrast agents can also potentially serve as radiosensitizers in radiotherapy. This study demonstrates that Gd can be used to enhance radiation dose in target volumes not only in HDR brachytherapy, but also in 6 MV FFF external beam radiotherapy, but higher than the currently used clinical concentration (>5 mg/mL) would be needed. PMID:25275550

  3. Anatomy-based definition of point A utilizing three-dimensional volumetric imaging approach for high-dose-rate (HDR) intracavitary brachytherapy dose prescription when treating cervical cancer using limited resources.

    PubMed

    Goyal, Manish K; Rai, D V; Kehwar, Than S; Manjhi, Jayanand; Heintz, Bret H; Shide, Kathleen L; Barker, Jerry L

    2016-07-16

    This study was designed to determine whether volumetric imaging could identify consistent alternative prescription methods to Manchester/point A when prescribing radiation dose in the treatment of cervical cancer using HDR intracavitary brachy-therapy (ICBT). One hundred and twenty-five treatment plans of 25 patients treated for carcinoma of the cervix were reviewed retrospectively. Each patient received 5 fractions of HDR ICBT following initial cisplatin-based pelvic chemoradiation, and radiation dose was originally prescribed to point A (ICRU-38). The gross tumor volume (GTV) and high-risk clinical target volume (HR-CTV) were contoured in three dimensions on the CT datasets, and inferior-superior, anterior-posterior, and left-right dimensions HR-CTV were recorded along with multiple anatomic and skeletal dimensions for each patient. The least square-best fit regression lines were plotted between one half of the HR-CTV width and pelvic cavity dimension at femoral head level and at maximum cavity dimension. The points in both plots lie reasonably close to straight lines and are well defined by straight lines with slopes of 0.15 and 0.17; intercept on y-axes of -0.08 and -0.03, point A, at the same level as defined based on applicator coordinates, is defined using this correlation, which is a function of distance between femoral heads/dimensions of maximum pelvic cavity width. Both relations, defined by straight lines, provide an estimated location of point A, which provides adequate coverage to the HR-CTV compared to the point A defined based on applicator coordinates. The point A defined based on femoral head distance would, therefore, be a reasonable surrogate to use for dose prescription because of subjective variation of cavity width dimension. Simple surrogate anatomic/skeletal landmarks can be useful for prescribing radiation dose when treating cervical cancer using intracavitary brachytherapy in limited-resource settings. Our ongoing work will continue to

  4. Anatomy-based definition of point A utilizing three-dimensional volumetric imaging approach for high-dose-rate (HDR) intracavitary brachytherapy dose prescription when treating cervical cancer using limited resources.

    PubMed

    Goyal, Manish K; Rai, D V; Kehwar, Than S; Manjhi, Jayanand; Heintz, Bret H; Shide, Kathleen L; Barker, Jerry L

    2016-11-01

    This study was designed to determine whether volumetric imaging could identify consistent alternative prescription methods to Manchester/point A when prescribing radiation dose in the treatment of cervical cancer using HDR intracavitary brachytherapy (ICBT). One hundred and twenty-five treatment plans of 25 patients treated for carcinoma of the cervix were reviewed retrospectively. Each patient received 5 fractions of HDR ICBT following initial cisplatin-based pelvic chemoradiation, and radiation dose was originally prescribed to point A (ICRU-38). The gross tumor volume (GTV) and high-risk clinical target volume (HR-CTV) were contoured in three dimensions on the CT datasets, and inferior-superior, anterior-posterior, and left-right dimensions HR-CTV were recorded along with multiple anatomic and skeletal dimensions for each patient. The least square-best fit regression lines were plotted between one half of the HR-CTV width and pelvic cavity dimension at femoral head level and at maximum cavity dimension. The points in both plots lie reasonably close to straight lines and are well defined by straight lines with slopes of 0.15 and 0.17; intercept on y-axes of -0.08 and -0.03, point A, at the same level as defined based on applicator coordinates, is defined using this correlation, which is a function of distance between femoral heads/dimensions of maximum pelvic cavity width. Both relations, defined by straight lines, provide an estimated location of point A, which provides adequate coverage to the HR-CTV compared to the point A defined based on applicator coordinates. The point A defined based on femoral head distance would, therefore, be a reasonable surrogate to use for dose prescription because of subjective variation of cavity width dimension. Simple surrogate anatomic/skeletal landmarks can be useful for prescribing radiation dose when treating cervical cancer using intracavitary brachytherapy in limited-resource settings. Our ongoing work will continue to

  5. Mixed convection radiative flow of three dimensional Maxwell fluid over an inclined stretching sheet in presence of thermophoresis and convective condition

    SciTech Connect

    Ashraf, M. Bilal; Hayat, T.; Shehzad, S. A.; Alsaedi, A.

    2015-02-15

    Three dimensional radiative flow of Maxwell fluid over an inclined stretching surface with convective boundary condition is investigated. Heat and mass transfer analysis is taken into account with thermophoresis effects. Similarity transformations are utilized to reduce the partial differential equations into ordinary differential equations. Series solutions of velocity, temperature and concentration are developed. Influence of different parameters Biot number, therrmophoretic parameter, Deborah number, ratio parameter, inclined stretching angle, radiation parameter, mixed convection parameter and concentration buoyancy parameter on the non-dimensional velocity components, temperature and concentration are plotted and discussed in detail. Physical quantities of interests are tabulated and examined.

  6. Mechanism of action for anti-radiation vaccine in reducing the biological impact of high-dose gamma irradiation

    NASA Astrophysics Data System (ADS)

    Maliev, Vladislav; Popov, Dmitri; Jones, Jeffrey A.; Casey, Rachael C.

    Ionizing radiation is a major health risk of long-term space travel, the biological consequences of which include genetic and oxidative damage. In this study, we propose an original mechanism by which high doses of ionizing radiation induce acute toxicity. We identified biological components that appear in the lymphatic vessels shortly after high-dose gamma irradiation. These radiation-induced toxins, which we have named specific radiation determinants (SRD), were generated in the irradiated tissues and then circulated throughout the body via the lymph circulation and bloodstream. Depending on the type of SRD elicited, different syndromes of acute radiation sickness (ARS) were expressed. The SRDs were developed into a vaccine used to confer active immunity against acute radiation toxicity in immunologically naïve animals. Animals that were pretreated with SRDs exhibited resistance to lethal doses of gamma radiation, as measured by increased survival times and survival rates. In comparison, untreated animals that were exposed to similar large doses of gamma radiation developed acute radiation sickness and died within days. This phenomenon was observed in a number of mammalian species. Initial analysis of the biochemical characteristics indicated that the SRDs were large molecular weight (200-250 kDa) molecules that were comprised of a mixture of protein, lipid, carbohydrate, and mineral. Further analysis is required to further identify the SRD molecules and the biological mechanism by which they mediate the toxicity associated with acute radiation sickness. By doing so, we may develop an effective specific immunoprophylaxis as a countermeasure against the acute effects of ionizing radiation.

  7. Three-dimensional modeling of genome macroarchitecture on the basis of its structural changes after the action of radiation

    NASA Astrophysics Data System (ADS)

    Aleksandrov, I. D.; Aleksandrova, M. V.; Zaikin, N. S.; Koren'kov, V. V.; Pervushova, O. V.; Stepanenko, V. A.

    2006-12-01

    At present, after 120 years of theoretical and experimental studies, the problem of the genome macroarchitecture as the highest level of interphase chromosome organization in the nucleus of somatic cells is still open. The problem of spatial organization of interphase chromosomes in the haploid nucleus of germ cells has never been studied. The three-dimensional modeling of spatial organization of part of the haploid genome (the second chromosome) in Drosophila melanogaster mature sperms is performed using mathematical methods and the methods of visualization of macromolecular biostructures. The frequency and arrangement of inversion breaks for 72 structural vg mutants were used as genetic markers under the assumption that both ends of each inversion are brought together and form loops of an appropriate size. For taking into account the spatial proximity and visualization of loop structures of the chromosome, modern methods of three-dimensional modeling with application of splines, Open GL library, Delphi, and Gmax were used. According to the model developed, the whole second chromosome in the nucleus of mature sperms is probably arranged in the form of the megarosette-loop structure, which can be assumed to be the fundamental ordered form of the genome macroarchitecture in haploid germs of higher organisms.

  8. High-dose selenium for the mitigation of radiation injury: a pilot study in a rat model.

    PubMed

    Sieber, Fritz; Muir, Sarah A; Cohen, Eric P; North, Paula E; Fish, Brian L; Irving, Amy A; Mäder, Marylou; Moulder, John E

    2009-03-01

    The purpose of this study was to evaluate in an animal model the safety and efficacy of dietary supplementation with high doses of selenium for the mitigation of the type of radiation injury that might be sustained during a nuclear accident or an act of radiological terrorism. Age-matched male rats were exposed to 10 Gy (single dose) of total-body irradiation (TBI) followed by a syngeneic bone marrow transplant, then randomized to standard drinking water or drinking water supplemented with sodium selenite or seleno-l-methionine. At 21 weeks after TBI, most rats on standard drinking water had severe renal failure with a mean blood urea nitrogen (BUN) level of 124 +/- 29 mg/dl (geometric mean +/- SE) whereas rats on selenium-supplemented drinking water (100 microg/day) had a mean BUN level of 67 +/- 12 mg/dl. The mitigating effect of selenium was confirmed by histopathological analyses. None of the animals on high-dose selenium showed signs of selenium toxicity. Our results suggest that dietary supplementation with high-dose selenium may provide a safe, effective and practical way to mitigate radiation injury to kidneys.

  9. Three-dimensional visualization of morphology and ventilation procedure (air flow and diffusion) of a subdivision of the acinus using synchrotron radiation microtomography of the human lung specimens

    NASA Astrophysics Data System (ADS)

    Shimizu, Kenji; Ikura, Hirohiko; Ikezoe, Junpei; Nagareda, Tomofumi; Yagi, Naoto; Umetani, Keiji; Imai, Yutaka

    2004-04-01

    We have previously reported a synchrotron radiation (SR) microtomography system constructed at the bending magnet beamline at the SPring-8. This system has been applied to the lungs obtained at autopsy and inflated and fixed by Heitzman"s method. Normal lung and lung specimens with two different types of pathologic processes (fibrosis and emphysema) were included. Serial SR microtomographic images were stacked to yield the isotropic volumetric data with high-resolution (12 μm3 in voxel size). Within the air spaces of a subdivision of the acinus, each voxel is segmented three-dimensionally using a region growing algorithm ("rolling ball algorithm"). For each voxel within the segmented air spaces, two types of voxel coding have been performed: single-seeded (SS) coding and boundary-seeded (BS) coding, in which the minimum distance from an initial point as the only seed point and all object boundary voxels as a seed set were calculated and assigned as the code values to each voxel, respectively. With these two codes, combinations of surface rendering and volume rendering techniques were applied to visualize three-dimensional morphology of a subdivision of the acinus. Furthermore, sequentially filling process of air into a subdivision of the acinus was simulated under several conditions to visualize the ventilation procedure (air flow and diffusion). A subdivision of the acinus was reconstructed three-dimensionally, demonstrating the normal architecture of the human lung. Significant differences in appearance of ventilation procedure were observed between normal and two pathologic processes due to the alteration of the lung architecture. Three-dimensional reconstruction of the microstructure of a subdivision of the acinus and visualization of the ventilation procedure (air flow and diffusion) with SR microtomography would offer a new approach to study the morphology, physiology, and pathophysiology of the human respiratory system.

  10. Three dimensional strained semiconductors

    DOEpatents

    Voss, Lars; Conway, Adam; Nikolic, Rebecca J.; Leao, Cedric Rocha; Shao, Qinghui

    2016-11-08

    In one embodiment, an apparatus includes a three dimensional structure comprising a semiconductor material, and at least one thin film in contact with at least one exterior surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the three dimensional structure. In another embodiment, a method includes forming a three dimensional structure comprising a semiconductor material, and depositing at least one thin film on at least one surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the structure.

  11. CONTROL OF LASER RADIATION PARAMETERS: Properties of self-compensation for three-dimensional periodic phase distortions in active media of gas-flow lasers

    NASA Astrophysics Data System (ADS)

    Lobachev, V. V.

    2003-10-01

    A mathematical model for optimising the beam formation direction in an active medium with three-dimensional periodic perturbations is developed. This model is applicable to the refractive-index distributions that can be represented in a multiplicative form with separated variables. The analysis of the actual structure of perturbations that appear behind the original nozzle assembly of a cw chemical laser has shown that the optimal direction of the beam formation lies in the region of partial self-compensation for distortions, which ensures an acceptable wave-front quality of the formed radiation.

  12. Intensity modulated radiation therapy versus three-dimensional conformal radiation therapy for the treatment of high grade glioma: a dosimetric comparison.

    PubMed

    MacDonald, Shannon M; Ahmad, Salahuddin; Kachris, Stefanos; Vogds, Betty J; DeRouen, Melissa; Gittleman, Alicia E; DeWyngaert, Keith; Vlachaki, Maria T

    2007-04-19

    The present study compared the dosimetry of intensity-modulated radiation therapy (IMRT) and three-dimensional conformal radiation therapy (3D-CRT) techniques in patients treated for high-grade glioma. A total of 20 patients underwent computed tomography treatment planning in conjunction with magnetic resonance imaging fusion. Prescription dose and normal-tissue constraints were identical for the 3D-CRT and IMRT plans. The prescribed dose was 59.4 Gy delivered at 1.8 Gy per fraction using 4-10 MV photons. Normal-tissue dose constraints were 50-54 Gy for the optic chiasm and nerves, and 55-60 Gy for the brainstem. The IMRT plan yielded superior target coverage as compared with the 3D-CRT plan. Specifically, minimum and mean planning target volume cone down doses were 54.52 Gy and 61.74 Gy for IMRT and 50.56 Gy and 60.06 Gy for 3D-CRT (p < or = 0.01). The IMRT plan reduced the percent volume of brainstem receiving a dose greater than 45 Gy by 31% (p = 0.004) and the percent volume of brain receiving a dose greater than 18 Gy, 24 Gy, and 45 Gy by 10% (p = 0.059), 14% (p = 0.015), and 40% (p < or = 0.0001) respectively. With IMRT, the percent volume of optic chiasm receiving more than 45 Gy was also reduced by 30.40% (p = 0.047). As compared with 3D-CRT, IMRT significantly increased the tumor control probability (p < or = 0.005) and lowered the normal-tissue complication probability for brain and brainstem (p < 0.033). Intensity-modulated radiation therapy improved target coverage and reduced radiation dose to the brain, brainstem, and optic chiasm. With the availability of new cancer imaging tools and more effective systemic agents, IMRT may be used to intensify tumor doses while minimizing toxicity, therefore potentially improving outcomes in patients with high-grade glioma.

  13. Effect of conjoint administration of tamoxifen and high-dose radiation on the development of mammary carcinoma

    SciTech Connect

    Kantorowitz, D.A. ); Thompson, H.J. ); Furmanski, P. )

    1993-04-30

    Tamoxifen is currently advocated for post-menopausal breast cancer patients receiving definitive irradiation after limited surgery. The purpose of this study was to assess in an experimental model for breast cancer whether the efficacy of irradiation is altered by conjoint administration of tamoxifen. To this end, rats with small tumors induced by 1-methyl-1-nitrosourea (MNU) were treated with tamoxifen, radiation, or a combination of the two modalities. Female Sprague Dawley rats were injected i.p. with 50 mg MNU/kg body weight at 50 days of age. At 64 days post carcinogen, the majority of the rats had at least one palpable mammary tumor. At that time radiation with or without tamoxifen treatment was initiated and given 5 days per week for 5 weeks. Radiation dose was 4500 cGy delivered as 25, 180 cGy fractions. Tamoxifen, 500 mg/kg body weight, was administered subcutaneously each day during the irradiation interval. The study was terminated 28 weeks after carcinogen treatment. High dose radiation alone induced a reduction in the size of existing tumors, but resulted in a significant increase in the number of tumors that were detected. Treatment with tamoxifen alone also caused a reduction in tumor volume, but had no effect on final incidence or number of mammary tumors. Combined modality treatment resulted in a significant reduction in the volume of existing tumors and suppressed the enhanced occurrence of additional tumors observed when only radiation alone was administered. The findings of this study indicate that in the context of fractionated, high dose radiation treatment of established mammary cancers, tamoxifen may reduce the likelihood of subsequent tumor development and by so doing prove a helpful simultaneous conjoint adjuvant treatment to post-operative irradiation. 35 refs., 1 fig., 2 tabs.

  14. Dose-volumetric parameters predicting radiation-induced hepatic toxicity in unresectable hepatocellular carcinoma patients treated with three-dimensional conformal radiotherapy

    SciTech Connect

    Kim, Tae Hyun; Kim, Dae Yong . E-mail: radiopia@ncc.re.kr; Park, Joong-Won; Kim, Seong Hoon; Choi, Joon-Il; Kim, Hyun Beom; Lee, Woo Jin; Park, Sang Jae; Hong, Eun Kyung; Kim, Chang-Min

    2007-01-01

    Purpose: To identify the dose-volumetric parameters associated with the risk of radiation-induced hepatic toxicity (RIHT) in hepatocellular carcinoma patients treated with three-dimensional conformal radiotherapy. Methods and Materials: A total of 105 hepatocellular carcinoma patients underwent three-dimensional conformal radiotherapy (total dose range, 44-58.5 Gy; median, 54). RIHT was scored within 4 months of completing three-dimensional conformal radiotherapy. The dose-volume parameters analyzed were the gross tumor volume; normal liver volume; total liver volume; radiation dose; mean dose to the normal liver; percentage of the normal liver volume receiving {>=}20, {>=}25, {>=}30, {>=}35, and {>=}40 Gy; percentage of the total liver volume receiving {>=}20, {>=}25, {>=}30, {>=}35, and {>=}40 Gy; and the normal tissue complication probability. Results: Of the 105 patients, Grade 1 RIHT was observed in 21 (20.0%), Grade 2 in 7 (6.7%), Grade 3 in 5 (4.8%), and Grade 4 in 1 (1.0%) patient. No fatal Grade 5 RIHT developed. On multivariate analysis for predicting Grade 2 or worse RIHT, the total liver volume receiving {>=}30 Gy was the only significant parameter (p < 0.001). Grade 2 or worse RIHT was observed in only 2 (2.4%) of 85 patients with a total liver volume receiving 30 Gy of {<=}60% and in 11 (55.0%) of 20 patients with >60% (p < 0.001). Conclusion: The total liver volume receiving {>=}30 Gy appears to be a useful dose-volumetric parameter for predicting the risk of RIHT. This volume should be limited to {<=}60% whenever possible to minimize the risk of Grade 2 or worse RIHT.

  15. Mechanism of Action for Anti-Radiation Vaccine in Reducing the Biological Impact of High-Dose Irradiation

    NASA Technical Reports Server (NTRS)

    Maliev, Vladislav; Popov, Dmitri; Jones, Jeffrey A.; Casey, Rachael C.

    2006-01-01

    Ionizing radiation is a major health risk of long-term space travel, the biological consequences of which include genetic and oxidative damage. In this study, we propose an original mechanism by which high doses of ionizing radiation induce acute toxicity. We identified biological components that appear in the lymphatic vessels shortly after gamma irradiation. These radiation-induced toxins, which we have named specific radiation determinants (SRD), were generated in the irradiated tissues and then collected and circulated throughout the body via the lymph circulation and bloodstream. Depending on the type of SRD elicited, different syndromes of acute radiation sickness (ARS) were expressed. The SRDs were developed into a vaccine used to confer active immunity against acute radiation toxicity in immunologically naive animals. Animals that were pretreated with SRDs exhibited resistance to lethal doses of gamma radiation, as measured by increased survival times and survival rates. In comparison, untreated animals that were exposed to similar large doses of gamma radiation developed acute radiation sickness and died within days. This phenomenon was observed in a number of mammalian species. We partially analyzed the biochemical characteristics of the SRDs. The SRDs were large molecular weight (200-250 kDa) molecules that were comprised of a mixture of protein, lipid, carbohydrate, and mineral. Further analysis is required to further identify the SRD molecules and the biological mechanism by which the mediate the toxicity associated with acute radiation sickness. By doing so, we may develop an effective specific immunoprophylaxis as a countermeasure against the acute effects of ionizing radiation.

  16. Mechanism of Action for Anti-radiation Vaccine in Reducing the Biological Impact of High-dose Gamma Irradiation

    NASA Technical Reports Server (NTRS)

    Maliev, Vladislav; Popov, Dmitri; Jones, Jeffrey A.; Casey, Rachael C.

    2007-01-01

    Ionizing radiation is a major health risk of long-term space travel, the biological consequences of which include genetic and oxidative damage. In this study, we propose an original mechanism by which high doses of ionizing radiation induce acute toxicity. We identified biological components that appear in the lymphatic vessels shortly after gamma irradiation. These radiation-induced toxins, which we have named specific radiation determinants (SRD), were generated in the irradiated tissues and then collected and circulated throughout the body via the lymph circulation and bloodstream. Depending on the type of SRD elicited, different syndromes of acute radiation sickness (ARS) were expressed. The SRDs were developed into a vaccine used to confer active immunity against acute radiation toxicity in immunologically naive animals. Animals that were pretreated with SRDs exhibited resistance to lethal doses of gamma radiation, as measured by increased survival times and survival rates. In comparison, untreated animals that were exposed to similar large doses of gamma radiation developed acute radiation sickness and died within days. This phenomenon was observed in a number of mammalian species. Initial analysis of the biochemical characteristics indicated that the SRDs were large molecular weight (200-250 kDa) molecules that were comprised of a mixture of protein, lipid, carbohydrate, and mineral. Further analysis is required to further identify the SRD molecules and the biological mechanism by which the mediate the toxicity associated with acute radiation sickness. By doing so, we may develop an effective specific immunoprophylaxis as a countermeasure against the acute effects of ionizing radiation.

  17. [Exploring the three-dimensional structure of dermal tissues of normal skin and scar in rat with synchrotron radiation X-ray imaging technology].

    PubMed

    Jiang, Yu-zhi; Tong, Ya-jun; Xiao, Ti-qiao; Xie, Hong-lan; Qing, Chun; DU, Guo-hao; Lu, Shu-liang

    2012-02-01

    To compare the morphological difference between dermal tissue of normal skin and that of scar in rat, and to explore its structural pattern. The full-thickness skin and the scar tissue formed 3 weeks after wound healing from SD rats were harvested as samples, which were prepared appropriately afterwards. Samples were scanned and imaged with synchrotron radiation technology, micro-CT, and phase-contrast imaging technology. The images were rebuilt with three-dimensional software. The micro-CT was materialized by using X-ray generated by synchrotron radiation light source. The structure of dermal tissues was clearly shown with the assistance of phase-contrast imaging technology in the process. It was demonstrated that the dermal tissues of normal skin of rat were mainly composed of collagenous fibers, which twined together to form an olive-like structure. These olive-like structures as basic units were arranged randomly in a certain way. The collagenous fibers in dermal tissue of the scar were arranged in a parallel manner, while some fibers were crooked and arranged in a disorderly manner. Dermal tissue of normal skin in rat has stable three-dimensional structure, and its basic structure and manner of composition are obviously different from those of scar dermal tissue.

  18. Quantum-mechanical calculation of three-dimensional atom-diatom collisions in the presence of intense laser radiation

    NASA Technical Reports Server (NTRS)

    Devries, P. L.; George, T. F.

    1979-01-01

    A formalism is presented for describing the collision of fluorine with the hydrogen molecule in the presence of intense radiation. For a laser frequency on the order of the spin-orbit splitting of fluorine, the interaction of the molecular system with the radiation occurs at relatively long range where, for this system, the electric dipole is vanishingly small. Hence the interaction occurs due to the magnetic dipole coupling. Even so, at low collision energies a substantial enhancement of the quenching cross section is found for a radiation intensity of 10 to the 11th W/sq cm.

  19. Quantum-mechanical calculation of three-dimensional atom-diatom collisions in the presence of intense laser radiation

    NASA Technical Reports Server (NTRS)

    Devries, P. L.; George, T. F.

    1979-01-01

    A formalism is presented for describing the collision of fluorine with the hydrogen molecule in the presence of intense radiation. For a laser frequency on the order of the spin-orbit splitting of fluorine, the interaction of the molecular system with the radiation occurs at relatively long range where, for this system, the electric dipole is vanishingly small. Hence the interaction occurs due to the magnetic dipole coupling. Even so, at low collision energies a substantial enhancement of the quenching cross section is found for a radiation intensity of 10 to the 11th W/sq cm.

  20. High doses of ionizing radiation on bone repair: is there effect outside the irradiated site?

    PubMed

    Rocha, Flaviana Soares; Dias, Pâmella Coelho; Limirio, Pedro Henrique Justino Oliveira; Lara, Vitor Carvalho; Batista, Jonas Dantas; Dechichi, Paula

    2017-03-01

    Local ionizing radiation causes damage to bone metabolism, it reduces blood supply and cellularity over time. Recent studies indicate that radiation promotes biological response outside the treatment field. The aim of this study was to investigate the effects of ionizing radiation on bone repair outside the irradiated field. Ten healthy male Wistar rats were used; and five animals were submitted to radiotherapy on the left femur. After 4 weeks, in all animals were created bone defects in the right and left femurs. Seven days after surgery, animals were euthanized. The femurs were removed and randomly divided into 3 groups (n=5): Control (C) (right femur of the non-irradiated animals); Local ionizing radiation (IR) (left femur of the irradiated animals); Contralateral ionizing radiation (CIR) (right femur of the irradiated animals). The femurs were processed and embedded in paraffin; and bone histologic sections were evaluated to quantify the bone neoformation. Histomorphometric analysis showed that there was no significant difference between groups C (24.6±7.04) and CIR (25.3±4.31); and IR group not showed bone neoformation. The results suggest that ionizing radiation affects bone repair, but does not interfere in bone repair distant from the primary irradiated site.

  1. Transcriptional response of ex vivo human skin to ionizing radiation: comparison between low- and high-dose effects.

    PubMed

    Albrecht, Huguette; Durbin-Johnson, Blythe; Yunis, Reem; Kalanetra, Karen M; Wu, Shiquan; Chen, Rachel; Stevenson, Thomas R; Rocke, David M

    2012-01-01

    Although human exposure to low-dose ionizing radiation can occur through a variety of sources, including natural, medical, occupational and accidental, the true risks of low-dose ionizing radiation are still poorly understood in humans. Here, the global transcriptional responses of human skin after ex vivo exposure to low (0.05 Gy) and high (5 Gy) doses of X rays and of time in culture (0 Gy) at 0, 2, 8 and 30 h postirradiation were analyzed and compared. Responses to low and high doses differed quantitatively and qualitatively. Differentially expressed genes fell into three groups: (1) unique genes defined as responsive to either 0.05 or 5 Gy but not both and also responsive to time in culture, (2) specific genes defined as responsive to either 0.05 or 5 Gy but not both and not responsive to time in culture, and (3) dose-independent responsive genes. Major differences observed in ex vivo irradiated skin between transcriptional responses to low or high doses were twofold. First, gene expression modulated by 0.05 Gy was transient, while in response to 5 Gy persistence of modified gene expression was observed for a limited number of genes. Second, neither TP53 nor TGFβ target genes were modulated after exposure to an acute low dose, suggesting that the TP53-dependent DNA damage response either was not triggered or was triggered only briefly.

  2. Transcriptional Response of Ex Vivo Human Skin to Ionizing Radiation: Comparison Between Low- and High-Dose Effects

    PubMed Central

    Albrecht, Huguette; Durbin-Johnson, Blythe; Yunis, Reem; Kalanetra, Karen M.; Wu, Shiquan; Chen, Rachel; Stevenson, Thomas R.; Rocke, David M.

    2013-01-01

    Although human exposure to low-dose ionizing radiation can occur through a variety of sources, including natural, medical, occupational and accidental, the true risks of low-dose ionizing radiation are still poorly understood in humans. Here, the global transcriptional responses of human skin after ex vivo exposure to low (0.05 Gy) and high (5 Gy) doses of X rays and of time in culture (0 Gy) at 0, 2, 8 and 30 h postirradiation were analyzed and compared. Responses to low and high doses differed quantitatively and qualitatively. Differentially expressed genes fell into three groups: (1) unique genes defined as responsive to either 0.05 or 5 Gy but not both and also responsive to time in culture, (2) specific genes defined as responsive to either 0.05 or 5 Gy but not both and not responsive to time in culture, and (3) dose-independent responsive genes. Major differences observed in ex vivo irradiated skin between transcriptional responses to low or high doses were twofold. First, gene expression modulated by 0.05 Gy was transient, while in response to 5 Gy persistence of modified gene expression was observed for a limited number of genes. Second, neither TP53 nor TGFβ target genes were modulated after exposure to an acute low dose, suggesting that the TP53-dependent DNA damage response either was not triggered or was triggered only briefly. PMID:22029842

  3. Three-dimensional data assimilation and reanalysis of radiation belt electrons: Observations over two solar cycles, and operational forecasting.

    NASA Astrophysics Data System (ADS)

    Kellerman, A. C.; Shprits, Y.; Kondrashov, D. A.; Podladchikova, T.; Drozdov, A.; Subbotin, D.; Makarevich, R. A.; Donovan, E.; Nagai, T.

    2015-12-01

    Understanding of the dynamics in Earth's radiation belts is critical to accurate modeling and forecasting of space weather conditions, both which are important for design, and protection of our space-borne assets. In the current study, we utilize the Versatile Electron Radiation Belt (VERB) code, multi-spacecraft measurements, and a split-operator Kalman filter to recontructe the global state of the radiation belt system in the CRRES era and the current era. The reanalysis has revealed a never before seen 4-belt structure in the radiation belts during the March 1991 superstorm, and highlights several important aspects in regards to the the competition between the source, acceleration, loss, and transport of particles. In addition to the above, performing reanalysis in adiabatic coordinates relies on specification of the Earth's magnetic field, and associated observational, and model errors. We determine the observational errors for the Kalman filter directly from cross-spacecraft phase-space density (PSD) conjunctions, and obtain the error in VERB by comparison with reanalysis over a long time period. Specification of errors associated with several magnetic field models provides an important insight into the applicability of such models for radiation belt research. The comparison of CRRES area reanalysis with Van Allen Probe era reanalysis allows us to perform a global comparison of the dynamics of the radiation belts during different parts of the solar cycle and during different solar cycles. The data assimilative model is presently used to perform operational forecasts of the radiation belts (http://rbm.epss.ucla.edu/realtime-forecast/).

  4. The Effect of High-Dose Ionizing Radiation on the Astrobiological Model Lichen Circinaria gyrosa.

    PubMed

    de la Torre, Rosa; Miller, Ana Zélia; Cubero, Beatriz; Martín-Cerezo, M Luisa; Raguse, Marina; Meeßen, Joachim

    2017-02-01

    The lichen Circinaria gyrosa is an astrobiological model defined by its high capacity of resistance to space conditions and to a simulated martian environment. Therefore, it became part of the currently operated BIOMEX experiment on board the International Space Station and the recent STARLIFE campaign to study the effects of four types of space-relevant ionizing radiation. The samples were irradiated with helium and iron ions at doses up to 2 kGy, with X-rays at doses up to 5 kGy and with γ rays at doses from 6 to 113 kGy. Results on C. gyrosa's resistance to simulated space ionizing radiation and its post-irradiation viability were obtained by (i) chlorophyll a fluorescence of photosystem II (PSII), (ii) epifluorescence microscopy, (iii) confocal laser scanning microscopy (CLSM), and (iv) field emission scanning electron microscopy (FESEM). Results of photosynthetic activity and epifluorescence show no significant changes up to a dose of 1 kGy (helium ions), 2 kGy (iron ions), 5 kGy (X-rays)-the maximum doses applied for those radiation qualities-as well as a dose of 6 kGy of γ irradiation, which was the lowest dose applied for this low linear energy transfer (LET) radiation. Significant damage in a dose-related manner was observed only at much higher doses of γ irradiation (up to 113 kGy). These data corroborate the findings of the parallel STARLIFE studies on the effects of ionizing radiation on the lichen Circinaria gyrosa, its isolated photobiont, and the lichen Xanthoria elegans. Key Words: Simulated space ionizing radiation-Gamma rays-Extremotolerance-Lichens-Circinaria gyrosa-Photosynthetic activity. Astrobiology 17, 145-153.

  5. Upregulated epidermal growth factor receptor expression following near-infrared irradiation simulating solar radiation in a three-dimensional reconstructed human corneal epithelial tissue culture model.

    PubMed

    Tanaka, Yohei; Nakayama, Jun

    2016-01-01

    Humans are increasingly exposed to near-infrared (NIR) radiation from both natural (eg, solar) and artificial (eg, electrical appliances) sources. Although the biological effects of sun and ultraviolet (UV) exposure have been extensively investigated, the biological effect of NIR radiation is still unclear. We previously reported that NIR as well as UV induces photoaging and standard UV-blocking materials, such as sunglasses, do not sufficiently block NIR. The objective of this study was to investigate changes in gene expression in three-dimensional reconstructed corneal epithelial tissue culture exposed to broad-spectrum NIR irradiation to simulate solar NIR radiation that reaches human tissues. DNA microarray and quantitative real-time polymerase chain reaction analysis were used to assess gene expression levels in a three-dimensional reconstructed corneal epithelial model composed of normal human corneal epithelial cells exposed to water-filtered broad-spectrum NIR irradiation with a contact cooling (20°C). The water-filter allowed 1,000-1,800 nm wavelengths and excluded 1,400-1,500 nm wavelengths. A DNA microarray with >62,000 different probes showed 25 and 150 genes that were up- or downregulated by at least fourfold and twofold, respectively, after NIR irradiation. In particular, epidermal growth factor receptor (EGFR) was upregulated by 19.4-fold relative to control cells. Quantitative real-time polymerase chain reaction analysis revealed that two variants of EGFR in human corneal epithelial tissue were also significantly upregulated after five rounds of 10 J/cm(2) irradiation (P<0.05). We found that NIR irradiation induced the upregulated expression of EGFR in human corneal cells. Since over half of the solar energy reaching the Earth is in the NIR region, which cannot be adequately blocked by eyewear and thus can induce eye damage with intensive or long-term exposure, protection from both UV and NIR radiation may prevent changes in gene expression and in

  6. Modeling of transient ionizing radiation effects in bipolar devices at high dose-rates

    SciTech Connect

    FJELDLY,T.A.; DENG,Y.; SHUR,M.S.; HJALMARSON,HAROLD P.; MUYSHONDT,ARNOLDO

    2000-04-25

    To optimally design circuits for operation at high intensities of ionizing radiation, and to accurately predict their a behavior under radiation, precise device models are needed that include both stationary and dynamic effects of such radiation. Depending on the type and intensity of the ionizing radiation, different degradation mechanisms, such as photoelectric effect, total dose effect, or single even upset might be dominant. In this paper, the authors consider the photoelectric effect associated with the generation of electron-hole pairs in the semiconductor. The effects of low radiation intensity on p-II diodes and bipolar junction transistors (BJTs) were described by low-injection theory in the classical paper by Wirth and Rogers. However, in BJTs compatible with modem integrated circuit technology, high-resistivity regions are often used to enhance device performance, either as a substrate or as an epitaxial layer such as the low-doped n-type collector region of the device. Using low-injection theory, the transient response of epitaxial BJTs was discussed by Florian et al., who mainly concentrated on the effects of the Hi-Lo (high doping - low doping) epilayer/substrate junction of the collector, and on geometrical effects of realistic devices. For devices with highly resistive regions, the assumption of low-level injection is often inappropriate, even at moderate radiation intensities, and a more complete theory for high-injection levels was needed. In the dynamic photocurrent model by Enlow and Alexander. p-n junctions exposed to high-intensity radiation were considered. In their work, the variation of the minority carrier lifetime with excess carrier density, and the effects of the ohmic electric field in the quasi-neutral (q-n) regions were included in a simplified manner. Later, Wunsch and Axness presented a more comprehensive model for the transient radiation response of p-n and p-i-n diode geometries. A stationary model for high-level injection in p

  7. The susceptibility of TaOx-based memristors to high dose rate ionizing radiation and total ionizing dose

    DOE PAGES

    McLain, Michael Lee; Sheridan, Timothy J.; Hjalmarson, Harold Paul; ...

    2014-11-11

    This paper investigates the effects of high dose rate ionizing radiation and total ionizing dose (TID) on tantalum oxide (TaOx) memristors. Transient data were obtained during the pulsed exposures for dose rates ranging from approximately 5.0 ×107 rad(Si)/s to 4.7 ×108 rad(Si)/s and for pulse widths ranging from 50 ns to 50 μs. The cumulative dose in these tests did not appear to impact the observed dose rate response. Static dose rate upset tests were also performed at a dose rate of ~3.0 ×108 rad(Si)/s. This is the first dose rate study on any type of memristive memory technology. Inmore » addition to assessing the tolerance of TaOx memristors to high dose rate ionizing radiation, we also evaluated their susceptibility to TID. The data indicate that it is possible for the devices to switch from a high resistance off-state to a low resistance on-state in both dose rate and TID environments. The observed radiation-induced switching is dependent on the irradiation conditions and bias configuration. Furthermore, the dose rate or ionizing dose level at which a device switches resistance states varies from device to device; the enhanced susceptibility observed in some devices is still under investigation. As a result, numerical simulations are used to qualitatively capture the observed transient radiation response and provide insight into the physics of the induced current/voltages.« less

  8. Evidence for Three-Dimensional Radiative Effects in MODIS Cloud Optical Depths Retrieved at Back Scattering View Angles

    NASA Technical Reports Server (NTRS)

    Varnai, Tamas; Marshak, Alexander

    2003-01-01

    This study addresses the question whether 1D radiative transfer theory describes well the angular distribution of shortwave cloud reflection. The statistical analysis of a large set of MODIS observations indicates that in oblique backward scattering directions, cloud reflection is stronger than 1D theory would predict. After considering a variety of possible causes, the paper concludes that the most likely reason for the increase lies in 3D radiative interactions. The results' main implication is that cloud optical depths retrieved at back scattering view angles larger than about 50 degrees tend to be overestimated and should be used only with great caution.

  9. The Effect of High-Dose Ionizing Radiation on the Astrobiological Model Lichen Circinaria gyrosa

    NASA Astrophysics Data System (ADS)

    de la Torre, Rosa; Zélia Miller, Ana; Cubero, Beatriz; Martín-Cerezo, M. Luisa; Raguse, Marina; Meeßen, Joachim

    2017-02-01

    The lichen Circinaria gyrosa is an astrobiological model defined by its high capacity of resistance to space conditions and to a simulated martian environment. Therefore, it became part of the currently operated BIOMEX experiment on board the International Space Station and the recent STARLIFE campaign to study the effects of four types of space-relevant ionizing radiation. The samples were irradiated with helium and iron ions at doses up to 2 kGy, with X-rays at doses up to 5 kGy and with γ rays at doses from 6 to 113 kGy. Results on C. gyrosa's resistance to simulated space ionizing radiation and its post-irradiation viability were obtained by (i) chlorophyll a fluorescence of photosystem II (PSII), (ii) epifluorescence microscopy, (iii) confocal laser scanning microscopy (CLSM), and (iv) field emission scanning electron microscopy (FESEM). Results of photosynthetic activity and epifluorescence show no significant changes up to a dose of 1 kGy (helium ions), 2 kGy (iron ions), 5 kGy (X-rays) - the maximum doses applied for those radiation qualities - as well as a dose of 6 kGy of γ irradiation, which was the lowest dose applied for this low linear energy transfer (LET) radiation. Significant damage in a dose-related manner was observed only at much higher doses of γ irradiation (up to 113 kGy). These data corroborate the findings of the parallel STARLIFE studies on the effects of ionizing radiation on the lichen Circinaria gyrosa, its isolated photobiont, and the lichen Xanthoria elegans.

  10. Comparative MicroRNA Expression Patterns in Fibroblasts after Low and High Doses of Low-LET Radiation Exposure

    NASA Technical Reports Server (NTRS)

    Maes, Olivier C.; Xu, Suying; Hada, Megumi; Wu, Honglu; Wang, Eugenia

    2007-01-01

    Exposure to ionizing radiation causes DNA damage to cells, and provokes a plethora of cellular responses controlled by unique gene-directed signaling pathways. MicroRNAs (miRNAs) are small (22-nucleotide), non-coding RNAs which functionally silence gene expression by either degrading the messages or inhibiting translation. Here we investigate radiation-dependent changes in these negative regulators by comparing the expression patterns of all 462 known human miRNAs in fibroblasts, after exposure to low (0.1 Gy) or high (2 Gy) doses of X-rays at 30 min, 2, 6 and 24 hrs post-treatment. The expression patterns of microRNAs after low and high doses of radiation show a similar qualitative down-regulation trend at early (0.5 hr) and late (24 hr) time points, with a quantitatively steeper slope following the 2 Gy exposures. Interestingly, an interruption of this downward trend is observed after the 2 Gy exposure, i.e. a significant up-regulation of microRNAs at 2 hrs, then reverting to the downward trend by 6 hrs; this interruption at the intermediate time point was not observed with the 0.1 Gy exposure. At the early time point (0.5 hr), candidate gene targets of selected down-regulated microRNAs, common to both 0.1 and 2 Gy exposures, were those functioning in chromatin remodeling. Candidate target genes of unique up-regulated microRNAs seen at a 2 hr intermediate time point, after the 2 Gy exposure only, are those involved in cell death signaling. Finally, putative target genes of down-regulated microRNAs seen at the late (24 hr) time point after either doses of radiation are those involved in the up-regulation of DNA repair, cell signaling and homeostasis. Thus we hypothesize that after radiation exposure, microRNAs acting as hub negative regulators for unique signaling pathways needed to be down-regulated so as to de-repress their target genes for the proper cellular responses, including DNA repair and cell maintenance. The unique microRNAs up-regulated at 2 hr after 2

  11. Low and high dose rate heavy ion radiation-induced intestinal and colonic tumorigenesis in APC(1638N/+) mice.

    PubMed

    Suman, Shubhankar; Kumar, Santosh; Moon, Bo-Hyun; Fornace, Albert J; Datta, Kamal

    2017-05-01

    Ionizing radiation (IR) is a recognized risk factor for colorectal cancer (CRC) and astronauts undertaking long duration space missions are expected to receive IR doses in excess of permissible limits with implications for colorectal carcinogenesis. Exposure to IR in outer space occurs at low doses and dose rates, and energetic heavy ions due to their high linear energy transfer (high-LET) characteristics remain a major concern for CRC risk in astronauts. Previously, we have demonstrated that intestinal tumorigenesis in a mouse model (APC(1638N/+)) of human colorectal cancer was significantly higher after exposure to high dose rate energetic heavy ions relative to low-LET γ radiation. The purpose of the current study was to compare intestinal tumorigenesis in APC(1638N/+) mice after exposure to energetic heavy ions at high (50cGy/min) and relatively low (0.33cGy/min) dose rate. Male and female mice (6-8 weeks old) were exposed to either 10 or 50cGy of (28)Si (energy: 300MeV/n; LET: 70keV/μm) or (56)Fe (energy: 1000MeV/n; LET: 148keV/μm) ions at NASA Space Radiation Laboratory in Brookhaven National Laboratory. Mice (n=20 mice/group) were euthanized and intestinal and colon tumor frequency and size were counted 150days after radiation exposure. Intestinal tumorigenesis in male mice exposed to (56)Fe was similar for high and low dose rate exposures. Although male mice showed a decreasing trend at low dose rate relative to high dose rate exposures, the differences in tumor frequency between the two types of exposures were not statistically significant after (28)Si radiation. In female mice, intestinal tumor frequency was similar for both radiation type and dose rates tested. In both male and female mice intestinal tumor size was not different after high and low dose rate radiation exposures. Colon tumor frequency in male and female mice after high and low dose rate energetic heavy ions was also not significantly different. In conclusion, intestinal and colonic

  12. Low and high dose rate heavy ion radiation-induced intestinal and colonic tumorigenesis in APC1638N/+ mice

    NASA Astrophysics Data System (ADS)

    Suman, Shubhankar; Kumar, Santosh; Moon, Bo-Hyun; Fornace, Albert J.; Datta, Kamal

    2017-05-01

    Ionizing radiation (IR) is a recognized risk factor for colorectal cancer (CRC) and astronauts undertaking long duration space missions are expected to receive IR doses in excess of permissible limits with implications for colorectal carcinogenesis. Exposure to IR in outer space occurs at low doses and dose rates, and energetic heavy ions due to their high linear energy transfer (high-LET) characteristics remain a major concern for CRC risk in astronauts. Previously, we have demonstrated that intestinal tumorigenesis in a mouse model (APC1638N/+) of human colorectal cancer was significantly higher after exposure to high dose rate energetic heavy ions relative to low-LET γ radiation. The purpose of the current study was to compare intestinal tumorigenesis in APC1638N/+ mice after exposure to energetic heavy ions at high (50 cGy/min) and relatively low (0.33 cGy/min) dose rate. Male and female mice (6-8 weeks old) were exposed to either 10 or 50 cGy of 28Si (energy: 300 MeV/n; LET: 70 keV/μm) or 56Fe (energy: 1000 MeV/n; LET: 148 keV/μm) ions at NASA Space Radiation Laboratory in Brookhaven National Laboratory. Mice (n = 20 mice/group) were euthanized and intestinal and colon tumor frequency and size were counted 150 days after radiation exposure. Intestinal tumorigenesis in male mice exposed to 56Fe was similar for high and low dose rate exposures. Although male mice showed a decreasing trend at low dose rate relative to high dose rate exposures, the differences in tumor frequency between the two types of exposures were not statistically significant after 28Si radiation. In female mice, intestinal tumor frequency was similar for both radiation type and dose rates tested. In both male and female mice intestinal tumor size was not different after high and low dose rate radiation exposures. Colon tumor frequency in male and female mice after high and low dose rate energetic heavy ions was also not significantly different. In conclusion, intestinal and colonic tumor

  13. Three-dimensional inhomogeneous rain fields: implications for the distribution of intensity and polarization of the microwave thermal radiation.

    NASA Astrophysics Data System (ADS)

    Ilyushin, Yaroslaw; Kutuza, Boris

    Observations and mapping of the upwelling thermal radiation of the Earth is the very promising remote sensing technique for the global monitoring of the weather and precipitations. For reliable interpretation of the observation data, numerical model of the microwave radiative transfer in the precipitating atmosphere is necessary. In the present work, numerical simulations of thermal microwave radiation in the rain have been performed at three wavelengths (3, 8 and 22 mm). Radiative properties of the rain have been simulated using public accessible T-matrix codes (Mishchenko, Moroz) for non-spherical particles of fixed orientation and realistic raindrop size distributions (Marshall-Palmer) within the range of rain intensity 1-100 mm/h. Thermal radiation of infinite flat slab medium and isolated rain cell of kilometer size has been simulated with finite difference scheme for the vectorial radiative transfer equation (VRTE) in dichroic scattering medium. Principal role of cell structure of the rain field in the formation of angular and spatial distribution of the intensity and polarization of the upwelling thermal radiation has been established. Possible approaches to interpretation of satellite data are also discussed. It is necessary that spatial resolution of microwave radiometers be less than rain cell size. At the present time the resolution is approximately 15 km. It can be considerably improved, for example by two-dimensional synthetic aperture millimeter-wave radiometric interferometer for measuring full-component Stokes vector of emission from hydrometeors. The estimates show that in millimeter band it is possible to develop such equipment with spatial resolution of the order of 1-2 km, which is significantly less than the size of rain cell, with sensitivity 0.3-0.5 K. Under this condition the second Stokes parameter may by successfully measured and may be used for investigation of precipitation regions. Y-shaped phased array antenna is the most promising to

  14. Three-dimensional, two-species magnetohydrodynamic studies of the early time behaviors of the Combined Release and Radiation Effects Satellite G2 barium release

    SciTech Connect

    Xie, Lianghai Li, Lei; Wang, Jingdong; Zhang, Yiteng

    2014-04-15

    We present a three-dimensional, two-species (Ba{sup +} and H{sup +}) MHD model to study the early time behaviors of a barium release at about 1 R{sub E} like Combined Release and Radiation Effects Satellite G2, with emphasis placed on the three-dimensional evolution of the barium cloud and its effects on the ambient plasma environment. We find that the perturbations caused by the cloud are the combined results of the initial injection, the radial expansion, and the diamagnetic effect and propagate as fast MHD waves in the magnetosphere. In return, the transverse expansion and the cross-B motion of barium ions are constrained by the magnetic force, which lead to a field-aligned striation of ions and the decoupling of these ions from the neutrals. Our simulation shows the formation and collapse of the diamagnetic cavity in the barium cloud. The estimated time scale for the cavity evolution might be much shorter if photoionization time scale and field aligned expansion of barium ions are considered. In addition, our two species MHD simulation also finds the snowplow effect resulting from the momentum coupling between barium ions and background H{sup +}, which creates density hole and bumps in the background H{sup +} when barium ions expanding along the magnetic field lines.

  15. Octave-wide photonic band gap in three-dimensional plasmonic Bragg structures and limitations of radiative coupling.

    PubMed

    Taubert, Richard; Dregely, Daniel; Stroucken, Tineke; Christ, Andre; Giessen, Harald

    2012-02-21

    Radiative coupling between oscillators is one of the most fundamental subjects of research in optics, where particularly a Bragg-type arrangement is of interest and has already been applied to atoms and excitons in quantum wells. Here we explore this arrangement in a plasmonic structure. We observe the emergence of an octave-wide photonic band gap in the optical regime. Compared with atomic or excitonic systems, the coupling efficiency of the particle plasmons utilized here is several orders of magnitude larger and widely tunable by changing the size and geometry of the plasmonic nanowires. We are thus able to explore the regime where the coupling distance is even limited by the large radiative decay rate of the oscillators. This Bragg-stacked coupling scheme will open a new route for future plasmonic applications such as far-field coupling to quantum emitters without quenching, plasmonic cavity structures and plasmonic distributed gain schemes for spasers.

  16. High-dose radiation therapy alone by moderate hypofractionation for patients with thoracic esophageal squamous cell carcinoma.

    PubMed

    Oh, Dongryul; Noh, Jae Myoung; Nam, Heerim; Lee, Hyebin; Kim, Tae Gyu; Ahn, Yong Chan

    2016-08-01

    We conducted retrospective analyses to investigate the clinical outcome of thoracic esophageal cancer patients who were treated with high-dose radiation therapy (RT) alone by moderate hypofractionation due to medical unfitness or refusal to receive either surgery or chemo-radiotherapy.Between May 2003 and April 2013, 70 patients were treated with high-dose RT alone with curative aim. The planned total RT dose was 60 Gy in daily 3.0 Gy per fraction. We evaluated the survival outcome, toxicities, and prognostic factors affecting patients' survival.At the time of analysis, 32 patients experienced disease progression. The 2-year overall survival (OS), cancer-specific survival (CSS) and local control (LC) rates were 52.1%, 57.8%, and 68.2%, respectively. Among them, 25 patients had superficial (cT1a-b) esophageal cancers, and the 2-year OS, CSS, and LC rates were 80.0%, 87.3%, and 81.6%, respectively. Multivariate analysis revealed that cT disease (P < 0.001) and tumor location (P = 0.022) were the significant factors for OS. The incidence of grade 3 or higher toxicities were 9.9%, including grade 3 esophagitis (2 patients, 2.8%) and grade 4 or 5 trachea-esophageal fistula (5 patients, 7.1%).High-dose RT alone by moderate hypofractionation had led to reasonable clinical outcomes at acceptable toxicity risk in thoracic esophageal cancer patients who are medically unfit or refuse surgery or chemotherapy, especially for the patients having superficial lesion.

  17. High-dose radiation therapy alone by moderate hypofractionation for patients with thoracic esophageal squamous cell carcinoma

    PubMed Central

    Oh, Dongryul; Noh, Jae Myoung; Nam, Heerim; Lee, Hyebin; Kim, Tae Gyu; Ahn, Yong Chan

    2016-01-01

    Abstract We conducted retrospective analyses to investigate the clinical outcome of thoracic esophageal cancer patients who were treated with high-dose radiation therapy (RT) alone by moderate hypofractionation due to medical unfitness or refusal to receive either surgery or chemo-radiotherapy. Between May 2003 and April 2013, 70 patients were treated with high-dose RT alone with curative aim. The planned total RT dose was 60 Gy in daily 3.0 Gy per fraction. We evaluated the survival outcome, toxicities, and prognostic factors affecting patients’ survival. At the time of analysis, 32 patients experienced disease progression. The 2-year overall survival (OS), cancer-specific survival (CSS) and local control (LC) rates were 52.1%, 57.8%, and 68.2%, respectively. Among them, 25 patients had superficial (cT1a-b) esophageal cancers, and the 2-year OS, CSS, and LC rates were 80.0%, 87.3%, and 81.6%, respectively. Multivariate analysis revealed that cT disease (P < 0.001) and tumor location (P = 0.022) were the significant factors for OS. The incidence of grade 3 or higher toxicities were 9.9%, including grade 3 esophagitis (2 patients, 2.8%) and grade 4 or 5 trachea-esophageal fistula (5 patients, 7.1%). High-dose RT alone by moderate hypofractionation had led to reasonable clinical outcomes at acceptable toxicity risk in thoracic esophageal cancer patients who are medically unfit or refuse surgery or chemotherapy, especially for the patients having superficial lesion. PMID:27537591

  18. Development and validation of a black carbon mixing state resolved three-dimensional model: Aging processes and radiative impact

    SciTech Connect

    Matsui, H.; Koike, Makoto; Kondo, Yutaka; Moteki, N.; Fast, Jerome D.; Zaveri, Rahul A.

    2013-03-16

    : A new two-dimensional aerosol bin scheme, which resolves both aerosol size and black carbon (BC) mixing state for BC aging processes (e.g., condensation and coagulation), has been developed and implemented into the WRF-chem model (MS-resolved WRF-chem). The mixing state of BC simulated by this model is compared with direct measurements over the East Asian region in spring 2009. Model simulations generally reproduce the observed features of the BC mixing state, such as the size-dependent number fractions of BC-containing and BC-free particles and the coating thickness of BC-containing particles. Sensitivity simulations show that the condensation process is dominant for the growth of thinly coated BC particles, while the coagulation process is necessary to produce thickly coated BC particles. Off-line optical and radiative calculations assuming an average mixing state for each size bin show that the domain- and period-averaged absorption coefficient and heating rate by aerosols are overestimated by 30 – 40% in the boundary layer compared with a benchmark simulation with the detailed treatment of mixing state. The absolute value of aerosol radiative forcing is also overestimated (10%, 3 W m-2) at the surface. However, these overestimations are reduced considerably when all the parameters (including mass and number concentration) are calculated with the simple treatment of mixing state. This is because the overestimation of radiative parameters due to higher absorption efficiency (compared with the benchmark simulation) is largely canceled by the underestimation of BC concentrations due to efficient wet removal processes. The overall errors in radiative forcing can be much smaller because of this cancellation but for the wrong reasons.

  19. Predictors of High-grade Esophagitis After Definitive Three-dimensional Conformal Therapy, Intensity-modulated Radiation Therapy, or Proton Beam Therapy for Non-small cell Lung Cancer

    SciTech Connect

    Gomez, Daniel R.; Tucker, Susan L.; Martel, Mary K.; Mohan, Radhe; Balter, Peter A.; Lopez Guerra, Jose Luis; Liu Hongmei; Komaki, Ritsuko; Cox, James D.; Liao Zhongxing

    2012-11-15

    Introduction: We analyzed the ability of various patient- and treatment-related factors to predict radiation-induced esophagitis (RE) in patients with non-small cell lung cancer (NSCLC) treated with three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), or proton beam therapy (PBT). Methods and Materials: Patients were treated for NSCLC with 3D-CRT, IMRT, or PBT at MD Anderson from 2000 to 2008 and had full dose-volume histogram (DVH) data available. The endpoint was severe (grade {>=}3) RE. The Lyman-Kutcher-Burman (LKB) model was used to analyze RE as a function of the fractional esophageal DVH, with clinical variables included as dose-modifying factors. Results: Overall, 652 patients were included: 405 patients were treated with 3D-CRT, 139 with IMRT, and 108 with PBT; corresponding rates of grade {>=}3 RE were 8%, 28%, and 6%, respectively, with a median time to onset of 42 days (range, 11-93 days). A fit of the fractional DVH LKB model demonstrated that the fractional effective dose was significantly different (P=.046) than 1 (fractional mean dose) indicating that high doses to small volumes are more predictive than mean esophageal dose. The model fit was better for 3D-CRT and PBT than for IMRT. Including receipt of concurrent chemotherapy as a dose-modifying factor significantly improved the LKB model (P=.005), and the model was further improved by including a variable representing treatment with >30 fractions. Examining individual types of chemotherapy agents revealed a trend toward receipt of concurrent taxanes and increased risk of RE (P=.105). Conclusions: Fractional dose (dose rate) and number of fractions (total dose) distinctly affect the risk of severe RE, estimated using the LKB model, and concurrent chemotherapy improves the model fit. This risk of severe RE is underestimated by this model in patients receiving IMRT.

  20. High-dose Radiation Induced Heart Damage in a Rat Model.

    PubMed

    Kiscsatári, Laura; Sárközy, Márta; Kővári, Bence; Varga, Zoltán; Gömöri, Kamilla; Morvay, Nikolett; Leprán, István; Hegyesi, Hargita; Fábián, Gabriella; Cserni, Bálint; Cserni, Gábor; Csont, Tamás; Kahán, Zsuzsanna

    Radiation-induced heart disease (RIHD) is a concern during radiotherapy. For its comprehensive study, an in vivo selective heart irradiation model was developed. Sprague-Dawley rats were irradiated with 50 Gy and functional imaging, biochemical (circulating growth differentiation factor-15 (GDF-15), transforming growth factor-beta (TGF-beta) and morphological (picrosirius red staining of the heart) objectives were tested. Signs and symptoms of RIHD occurred >12 weeks after irradiation with tachypnea, systolic and diastolic dysfunction, cardiac hypertrophy and body development retardation. Plasma GDF-15 was increased 3, 12 and 26, while plasma TGF-beta was increased 12 weeks after irradiation. At autopsy, extensive pleural fluid was found in the irradiated animals. Interstitial fibrosis could be reliably detected and quantified in irradiated hearts after a follow-up time of 19 weeks. The studied parameters could be used in future experiments for testing protective agents for prevention of radiation heart injury. Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  1. Study of high-dose x-ray radiation damage of silicon sensors

    NASA Astrophysics Data System (ADS)

    Schwandt, Joern; Fretwurst, Eckhart; Klanner, Robert; Pintilie, Ioana; Zhang, Jiaguo

    2013-05-01

    The high intensity and high repetition rate of the XFEL, the European X-ray Free-Electron Laser presently under construction in Hamburg, results in X-ray doses of up to 1 GGy in silicon sensors for 3 years of operation. Within the AGIPD Collaboration the Hamburg group has systematically studied X-ray-radiation damage using test structures and segmented sensors fabricated on high-ohmic n-type silicon. MOS Capacitors and Gate- Controlled Diodes from 4 vendors with different crystal orientations and different technological parameters, as well as strip sensors have been irradiated in the dose range between 10 kGy and 1 GGy. Current-Voltage, Capacitance/Conductance-Voltage and Thermal Dielectric Relaxation Current measurements were used to extract oxide-charge densities, interface-trap densities and surface-current densities as function of dose and annealing conditions. The results have been implemented into TCAD simulations, and the radiation performance of strip sensors and guard-ring structures simulated and compared to experimental results. Finally, with the help of detailed TCAD simulations, the layout and technological parameters of the AGIPD pixel sensor have been optimized. It is found that the optimization for sensors exposed to high X-ray doses is significantly different than for non-irradiated sensors, and that the specifications of the AGIPD sensor can be met. In 2012 sensors have been ordered, the first batch has been delivered recently, and first results on a comparison between simulations and measurements will be presented.

  2. Meridian is a three-dimensional network from bio-electromagnetic radiation interference: an interference hypothesis of meridian.

    PubMed

    Han, Jinxiang

    2012-03-01

    An electromagnetic radiation field within a biological organism is characterized by non-local interference. The interfering beams form a unitary tridimensional network with beams of varying intensity, also called striae, which are distributed on the organism surface. These striae are equivalent to semi-reflectors. The striae carry bio-information of corresponding organs and, thus, integrate all tissues, and organs of the organism. The longitudinal striae are classified as channels, while the transverse striae are collaterals. The acupoints are seen as the points where electromagnetic interfering striae intersect or converge. This hypothesis builds a foundation to understand the traditional Chinese medicine, including acupuncture, from the perspective of scientific knowledge.

  3. Validation of three-dimensional radiative transfer in coastal-ocean water systems as modeled by DIRSIG

    NASA Astrophysics Data System (ADS)

    Speir, Jacqueline Amy

    The radiative transfer equation (RTE) is a mathematical description of radiative gains and losses experienced by a propagating electromagnetic wave in a participating medium. Except for an isotropic lossless vacuum, all other volumes have the potential to scatter, absorb and emit radiant energy. Of these possible events, the global scattering term is the greatest obstacle between a radiative transfer problem and its solution. Historically, the RTE has been solved using a host of analytical approximations and numerical methods. Typical solution models exploit plane-parallel assumptions where it is assumed that optical properties may vary vertically with depth, but have an infinite horizontal extent. For more complicated scenarios that include pronounced 3D variability, a Monte Carlo statistical approach to the radiative transfer solution is often utilized. This statistical approach has been integrated within the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model in the form of photon mapping. Photon mapping provides a probabilistic solution to the in-scattered radiance problem, by employing a two-pass technique that first populates a photon map based on a Monte Carlo solution to the global scattering term, and then later uses this map to reconstruct the in-scattered radiance distribution during a traditional raytracing pass. As with any computational solution, the actual implementation of the technique requires assumptions, simplifications and integration within a cohesive rendering model. Moreover, the realistic simulation of any environment requires several other radiometric solutions that are not directly related to the photon mapped in-scattered radiance. This research attempts to validate raytraced and photon mapped contributions to sensor reaching radiance that can be expected in typical littoral environments, including boundary interface, medium and submerged or floating object effects. This is accomplished by comparing DIRSIG modeled results

  4. Assessment of The Dose-Response Relationship of Radiation-Induced Bystander Effect in Two Cell Lines Exposed to High Doses of Ionizing Radiation (6 and 8 Gy)

    PubMed Central

    Bahreyni Toossi, Mohammad Taghi; Khademi, Sara; Azimian, Hosein; Mohebbi, Shokoufeh; Soleymanifard, Shokouhozaman

    2017-01-01

    Objective The dose-response relationship of radiation-induced bystander effect (RIBE) is controversial at high dose levels. The aim of the present study is to assess RIBE at high dose levels by examination of different endpoints. Materials and Methods This experimental study used the medium transfer technique to induce RIBE. The cells were divided into two main groups: QU-DB cells which received medium from autologous irradiated cells and MRC5 cells which received medium from irradiated QU-DB cells. Colony, MTT, and micronucleus assays were performed to quantify bystander responses. The medium was diluted and transferred to bystander cells to investigate whether medium dilution could revive the RIBE response that disappeared at a high dose. Results The RIBE level in QU-DB bystander cells increased in the dose range of 0.5 to 4 Gy, but decreased at 6 and 8 Gy. The Micronucleated cells per 1000 binucleated cells (MNBN) frequency of QU-DB bystander cells which received the most diluted medium from 6 and 8 Gy QU-DB irradiated cells reached the maximum level compared to the MNBN frequency of the cells that received complete medium (P<0.0001). MNBN frequency of MRC5 cells which received the most diluted medium from 4 Gy QU-DB irradiated cells reached the maximum level compared to MNBN frequency of cells that received complete medium (P<0.0001). Conclusion Our results showed that RIBE levels decreased at doses above 4 Gy; however, RIBE increased when diluted conditioned medium was transferred to bystander cells. This finding confirmed that a negative feedback mechanism was responsible for the decrease in RIBE response at high doses. Decrease of RIBE at high doses might be used to predict that in radiosurgery, brachytherapy and grid therapy, in which high dose per fraction is applied, normal tissue damage owing to RIBE may decrease. PMID:28836405

  5. Assessment of The Dose-Response Relationship of Radiation-Induced Bystander Effect in Two Cell Lines Exposed to High Doses of Ionizing Radiation (6 and 8 Gy).

    PubMed

    Bahreyni Toossi, Mohammad Taghi; Khademi, Sara; Azimian, Hosein; Mohebbi, Shokoufeh; Soleymanifard, Shokouhozaman

    2017-10-01

    The dose-response relationship of radiation-induced bystander effect (RIBE) is controversial at high dose levels. The aim of the present study is to assess RIBE at high dose levels by examination of different endpoints. This experimental study used the medium transfer technique to induce RIBE. The cells were divided into two main groups: QU-DB cells which received medium from autologous irradiated cells and MRC5 cells which received medium from irradiated QU-DB cells. Colony, MTT, and micronucleus assays were performed to quantify bystander responses. The medium was diluted and transferred to bystander cells to investigate whether medium dilution could revive the RIBE response that disappeared at a high dose. The RIBE level in QU-DB bystander cells increased in the dose range of 0.5 to 4 Gy, but decreased at 6 and 8 Gy. The Micronucleated cells per 1000 binucleated cells (MNBN) frequency of QU-DB bystander cells which received the most diluted medium from 6 and 8 Gy QU-DB irradiated cells reached the maximum level compared to the MNBN frequency of the cells that received complete medium (P<0.0001). MNBN frequency of MRC5 cells which received the most diluted medium from 4 Gy QU-DB irradiated cells reached the maximum level compared to MNBN frequency of cells that received complete medium (P<0.0001). Our results showed that RIBE levels decreased at doses above 4 Gy; however, RIBE increased when diluted conditioned medium was transferred to bystander cells. This finding confirmed that a negative feedback mechanism was responsible for the decrease in RIBE response at high doses. Decrease of RIBE at high doses might be used to predict that in radiosurgery, brachytherapy and grid therapy, in which high dose per fraction is applied, normal tissue damage owing to RIBE may decrease.

  6. Influence of nonlinear thermal radiation and viscous dissipation on three-dimensional flow of Jeffrey nano fluid over a stretching sheet in the presence of Joule heating

    NASA Astrophysics Data System (ADS)

    Ganesh Kumar, K.; Rudraswamy, N. G.; Gireesha, B. J.; Krishnamurthy, M. R.

    2017-09-01

    Present exploration discusses the combined effect of viscous dissipation and Joule heating on three dimensional flow and heat transfer of a Jeffrey nanofluid in the presence of nonlinear thermal radiation. Here the flow is generated over bidirectional stretching sheet in the presence of applied magnetic field by accounting thermophoresis and Brownian motion of nanoparticles. Suitable similarity transformations are employed to reduce the governing partial differential equations into coupled nonlinear ordinary differential equations. These nonlinear ordinary differential equations are solved numerically by using the Runge-Kutta-Fehlberg fourth-fifth order method with shooting technique. Graphically results are presented and discussed for various parameters. Validation of the current method is proved by comparing our results with the existing results under limiting situations. It can be concluded that combined effect of Joule and viscous heating increases the temperature profile and thermal boundary layer thickness.

  7. Tree crown structural characterization: A study using terrestrial laser scanning and three-dimensional radiative transfer modeling

    NASA Astrophysics Data System (ADS)

    Moorthy, Inian

    Spectroscopic observational data for vegetated environments, have been coupled with 3D physically-based radiative transfer models for retrievals of biochemical and biophysical indicators of vegetation health and condition. With the recent introduction of Terrestrial Laser Scanning (TLS) units, there now exists a means of rapidly measuring intricate structural details of vegetation canopies, which can also serve as input into 3D radiative transfer models. In this investigation, Intelligent Laser Ranging and Imaging System (ILRIS-3D) data was acquired of individual tree crowns in laboratory, and field-based experiments. The ILRIS-3D uses the Time-Of-Flight (TOF) principle to measure the distances of objects based on the time interval between laser pulse exitance and return, upon reflection from an object. At the laboratory-level, this exploratory study demonstrated and validated innovative approaches for retrieving crown-level estimates of Leaf Area Index (LAI) (r2 = 0.98, rmse = 0.26m2/m2), a critical biophysical parameter for vegetation monitoring and modeling. These methods were implemented and expanded in field experiments conducted in olive (Olea europaea L.) orchards in Cordoba, Spain, where ILRIS-3D observations for 24 structurally-variable trees were made. Robust methodologies were developed to characterize diagnostic architectural parameters, such as tree height (r2 = 0.97, rmse = 0.21m), crown width (r 2 = 0.98, rmse = 0.12m), crown height (r2 = 0.81, rmse = 0.11m), crown volume (r2 = 0.99, rmse = 2.6m3), and LAI (r2 = 0.76, rmse = 0.27m2/ m2). These parameters were subsequently used as direct inputs into the Forest LIGHT (FLIGHT) 3D ray tracing model for characterization of the spectral behavior of the olive crowns. Comparisons between FLIGHT-simulated spectra and measured data showed small differences in the visible (< 3%) and near infrared (< 10%) spectral ranges. These differences between model simulations and measurements were significantly correlated

  8. PORTA: A three-dimensional multilevel radiative transfer code for modeling the intensity and polarization of spectral lines with massively parallel computers

    NASA Astrophysics Data System (ADS)

    Štěpán, Jiří; Trujillo Bueno, Javier

    2013-09-01

    The interpretation of the intensity and polarization of the spectral line radiation produced in the atmosphere of the Sun and of other stars requires solving a radiative transfer problem that can be very complex, especially when the main interest lies in modeling the spectral line polarization produced by scattering processes and the Hanle and Zeeman effects. One of the difficulties is that the plasma of a stellar atmosphere can be highly inhomogeneous and dynamic, which implies the need to solve the non-equilibrium problem of the generation and transfer of polarized radiation in realistic three-dimensional (3D) stellar atmospheric models. Here we present PORTA, an efficient multilevel radiative transfer code we have developed for the simulation of the spectral line polarization caused by scattering processes and the Hanle and Zeeman effects in 3D models of stellar atmospheres. The numerical method of solution is based on the non-linear multigrid iterative method and on a novel short-characteristics formal solver of the Stokes-vector transfer equation which uses monotonic Bézier interpolation. Therefore, with PORTA the computing time needed to obtain at each spatial grid point the self-consistent values of the atomic density matrix (which quantifies the excitation state of the atomic system) scales linearly with the total number of grid points. Another crucial feature of PORTA is its parallelization strategy, which allows us to speed up the numerical solution of complicated 3D problems by several orders of magnitude with respect to sequential radiative transfer approaches, given its excellent linear scaling with the number of available processors. The PORTA code can also be conveniently applied to solve the simpler 3D radiative transfer problem of unpolarized radiation in multilevel systems.

  9. Alteration of the serum N-glycome of mice locally exposed to high doses of ionizing radiation.

    PubMed

    Chaze, Thibault; Slomianny, Marie-Christine; Milliat, Fabien; Tarlet, Georges; Lefebvre-Darroman, Tony; Gourmelon, Patrick; Bey, Eric; Benderitter, Marc; Michalski, Jean-Claude; Guipaud, Olivier

    2013-02-01

    Exposure of the skin to ionizing radiation leads to characteristic reactions that will often turn into a pathophysiological process called the cutaneous radiation syndrome. The study of this disorder is crucial to finding diagnostic and prognostic bioindicators of local radiation exposure or radiation effects. It is known that irradiation alters the serum proteome content and potentially post-translationally modifies serum proteins. In this study, we investigated whether localized irradiation of the skin alters the serum glycome. Two-dimensional differential in-gel electrophoresis of serum proteins from a man and from mice exposed to ionizing radiation showed that potential post-translational modification changes occurred following irradiation. Using a large-scale quantitative mass-spectrometry-based glycomic approach, we performed a global analysis of glycan structures of serum proteins from non-irradiated and locally irradiated mice exposed to high doses of γ-rays (20, 40, and 80 Gy). Non-supervised descriptive statistical analyses (principal component analysis) using quantitative glycan structure data allowed us to discriminate between uninjured/slightly injured animals and animals that developed severe lesions. Decisional statistics showed that several glycan families were down-regulated whereas others increased, and that particular structures were statistically significantly changed in the serum of locally irradiated mice. The observed increases in multiantennary N-glycans and in outer branch fucosylation and sialylation were associated with the up-regulation of genes involved in glycosylation in the liver, which is the main producer of serum proteins, and with an increase in the key proinflammatory serum cytokines IL-1β, IL-6, and TNFα, which can regulate the expression of glycosylation genes. Our results suggest for the first time a role of serum protein glycosylation in response to irradiation. These protein-associated glycan structure changes might

  10. Alteration of the Serum N-glycome of Mice Locally Exposed to High Doses of Ionizing Radiation*

    PubMed Central

    Chaze, Thibault; Slomianny, Marie-Christine; Milliat, Fabien; Tarlet, Georges; Lefebvre-Darroman, Tony; Gourmelon, Patrick; Bey, Eric; Benderitter, Marc; Michalski, Jean-Claude; Guipaud, Olivier

    2013-01-01

    Exposure of the skin to ionizing radiation leads to characteristic reactions that will often turn into a pathophysiological process called the cutaneous radiation syndrome. The study of this disorder is crucial to finding diagnostic and prognostic bioindicators of local radiation exposure or radiation effects. It is known that irradiation alters the serum proteome content and potentially post-translationally modifies serum proteins. In this study, we investigated whether localized irradiation of the skin alters the serum glycome. Two-dimensional differential in-gel electrophoresis of serum proteins from a man and from mice exposed to ionizing radiation showed that potential post-translational modification changes occurred following irradiation. Using a large-scale quantitative mass-spectrometry-based glycomic approach, we performed a global analysis of glycan structures of serum proteins from non-irradiated and locally irradiated mice exposed to high doses of γ-rays (20, 40, and 80 Gy). Non-supervised descriptive statistical analyses (principal component analysis) using quantitative glycan structure data allowed us to discriminate between uninjured/slightly injured animals and animals that developed severe lesions. Decisional statistics showed that several glycan families were down-regulated whereas others increased, and that particular structures were statistically significantly changed in the serum of locally irradiated mice. The observed increases in multiantennary N-glycans and in outer branch fucosylation and sialylation were associated with the up-regulation of genes involved in glycosylation in the liver, which is the main producer of serum proteins, and with an increase in the key proinflammatory serum cytokines IL-1β, IL-6, and TNFα, which can regulate the expression of glycosylation genes. Our results suggest for the first time a role of serum protein glycosylation in response to irradiation. These protein-associated glycan structure changes might

  11. The Effect of High-Dose Ionizing Radiation on the Isolated Photobiont of the Astrobiological Model Lichen Circinaria gyrosa.

    PubMed

    Meeßen, Joachim; Backhaus, Theresa; Brandt, Annette; Raguse, Marina; Böttger, Ute; de Vera, Jean-Pierre; de la Torre, Rosa

    2017-02-01

    Lichen symbioses between fungi and algae represent successful life strategies to colonize the most extreme terrestrial habitats. Consequently, space exposure and simulation experiments have demonstrated lichens' high capacity for survival, and thus, they have become models in astrobiological research with which to discern the limits and limitations of terrestrial life. In a series of ground-based irradiation experiments, the STARLIFE campaign investigated the resistance of astrobiological model organisms to galactic cosmic radiation, which is one of the lethal stressors of extraterrestrial environments. Since previous studies have identified that the alga is the more sensitive lichen symbiont, we chose the isolated photobiont Trebouxia sp. of the astrobiological model Circinaria gyrosa as a subject in the campaign. Therein, γ radiation was used to exemplify the deleterious effects of low linear energy transfer (LET) ionizing radiation at extremely high doses up to 113 kGy in the context of astrobiology. The effects were analyzed by chlorophyll a fluorescence of photosystem II (PSII), cultivation assays, live/dead staining and confocal laser scanning microscopy (CLSM), and Raman laser spectroscopy (RLS). The results demonstrate dose-dependent impairment of photosynthesis, the cessation of cell proliferation, cellular damage, a decrease in metabolic activity, and degradation of photosynthetic pigments. While previous investigations on other extraterrestrial stressors have demonstrated a high potential of resistance, results of this study reveal the limits of photobiont resistance to ionizing radiation and characterize γ radiation-induced damages. This study also supports parallel STARLIFE studies on the lichens Circinaria gyrosa and Xanthoria elegans, both of which harbor a Trebouxia sp. photobiont. Key Words: Astrobiology-Gamma rays-Extremotolerance-Ionizing radiation-Lichens-Photobiont. Astrobiology 17, 154-162.

  12. Comparison of Acute and Late Toxicities for Three Modern High-Dose Radiation Treatment Techniques for Localized Prostate Cancer

    SciTech Connect

    Mohammed, Nasiruddin; Kestin, Larry; Ghilezan, Mihai; Krauss, Daniel; Vicini, Frank; Brabbins, Donald; Gustafson, Gary; Ye Hong; Martinez, Alavaro

    2012-01-01

    Purpose: We compared acute and late genitourinary (GU) and gastrointestinal (GI) toxicities in prostate cancer patients treated with three different high-dose radiation techniques. Methods and Materials: A total of 1,903 patients with localized prostate cancer were treated with definitive RT at William Beaumont Hospital from 1992 to 2006: 22% with brachytherapy alone (BT), 55% with image-guided external beam (EB-IGRT), and 23% external beam with high-dose-rate brachytherapy boost (EBRT+HDR). Median dose with BT was 120 Gy for LDR and 38 Gy for HDR (9.5 Gy Multiplication-Sign 4). Median dose with EB-IGRT was 75.6 Gy (PTV) to prostate with or without seminal vesicles. For EBRT+HDR, the pelvis was treated to 46 Gy with an additional 19 Gy (9.5 Gy Multiplication-Sign 2) delivered via HDR. GI and GU toxicity was evaluated utilizing the NCI-CTC criteria (v.3.0). Median follow-up was 4.8 years. Results: The incidences of any acute {>=} Grade 2 GI or GU toxicities were 35%, 49%, and 55% for BT, EB-IGRT, and EBRT+HDR (p < 0.001). Any late GU toxicities {>=} Grade 2 were present in 22%, 21%, and 28% for BT, EB-IGRT, and EBRT+HDR (p = 0.01), respectively. Patients receiving EBRT+HDR had a higher incidence of urethral stricture and retention, whereas dysuria was most common in patients receiving BT. Any Grade {>=}2 late GI toxicities were 2%, 20%, and 9% for BT, EB-IGRT, and EBRT+HDR (p < 0.001). Differences were most pronounced for rectal bleeding, with 3-year rates of 0.9%, 20%, and 6% (p < 0.001) for BT, EB-IGRT, and EBRT+HDR respectively. Conclusions: Each of the three modern high-dose radiation techniques for localized prostate cancer offers a different toxicity profile. These data can help patients and physicians to make informed decisions regarding radiotherapy for prostate andenocarcinoma.

  13. Coupling sky images with three-dimensional radiative transfer models: a new method to estimate cloud optical depth

    NASA Astrophysics Data System (ADS)

    Mejia, F. A.; Kurtz, B.; Murray, K.; Hinkelman, L. M.; Sengupta, M.; Xie, Y.; Kleissl, J.

    2015-10-01

    A method for retrieving cloud optical depth (τc) using a ground-based sky imager (USI) is presented. The Radiance Red-Blue Ratio (RRBR) method is motivated from the analysis of simulated images of various τc produced by a 3-D Radiative Transfer Model (3DRTM). From these images the basic parameters affecting the radiance and RBR of a pixel are identified as the solar zenith angle (θ0), τc, solar pixel angle/scattering angle (ϑs), and pixel zenith angle/view angle (ϑz). The effects of these parameters are described and the functions for radiance, Iλ(τc, θ0, ϑs, ϑz) and the red-blue ratio, RBR(τc, θ0, ϑs, ϑz) are retrieved from the 3DRTM results. RBR, which is commonly used for cloud detection in sky images, provides non-unique solutions for τc, where RBR increases with τc up to about τc = 1 (depending on other parameters) and then decreases. Therefore, the RRBR algorithm uses the measured Iλmeas(ϑs, ϑz), in addition to RBRmeas(ϑs, ϑz) to obtain a unique solution for τc. The RRBR method is applied to images taken by a USI at the Oklahoma Atmospheric Radiation Measurement program (ARM) site over the course of 220 days and validated against measurements from a microwave radiometer (MWR); output from the Min method for overcast skies, and τc retrieved by Beer's law from direct normal irradiance (DNI) measurements. A τc RMSE of 5.6 between the Min method and the USI are observed. The MWR and USI have an RMSE of 2.3 which is well within the uncertainty of the MWR. An RMSE of 0.95 between the USI and DNI retrieved τc is observed. The procedure developed here provides a foundation to test and develop other cloud detection algorithms.

  14. Three-dimensional, Time-Resolved, Intrafraction Motion Monitoring Throughout Stereotactic Liver Radiation Therapy on a Conventional Linear Accelerator

    SciTech Connect

    Worm, Esben S.; Høyer, Morten; Fledelius, Walter; Poulsen, Per R.

    2013-05-01

    Purpose: To investigate the time-resolved 3-dimensional (3D) internal motion throughout stereotactic body radiation therapy (SBRT) of tumors in the liver using standard x-ray imagers of a conventional linear accelerator. Methods and Materials: Ten patients with implanted gold markers received 11 treatment courses of 3-fraction SBRT in a stereotactic body-frame on a conventional linear accelerator. Two pretreatment and 1 posttreatment cone-beam computed tomography (CBCT) scans were acquired during each fraction. The CBCT projection images were used to estimate the internal 3D marker motion during CBCT acquisition with 11-Hz resolution by a monoscopic probability-based method. Throughout the treatment delivery by conformal or volumetric modulated arc fields, simultaneous MV portal imaging (8 Hz) and orthogonal kV imaging (5 Hz) were applied to determine the 3D marker motion using either MV/kV triangulation or the monoscopic method when marker segmentation was unachievable in either MV or kV images. The accuracy of monoscopic motion estimation was quantified by also applying monoscopic estimation as a test for all treatments during which MV/kV triangulation was possible. Results: Root-mean-square deviations between monoscopic estimations and triangulations were less than 1.0 mm. The mean 3D intrafraction and intrafield motion ranges during liver SBRT were 17.6 mm (range, 5.6-39.5 mm) and 11.3 mm (2.1-35.5mm), respectively. The risk of large intrafraction baseline shifts correlated with intrafield respiratory motion range. The mean 3D intrafractional marker displacement relative to the first CBCT was 3.4 mm (range, 0.7-14.5 mm). The 3D displacements exceeded 8.8 mm 10% of the time. Conclusions: Highly detailed time-resolved internal 3D motion was determined throughout liver SBRT using standard imaging equipment. Considerable intrafraction motion was observed. The demonstrated methods provide a widely available approach for motion monitoring that, combined with motion

  15. Study of bulk damage in high resistivity silicon detectors irradiated by high dose of {sup 60}Co {gamma}-radiation

    SciTech Connect

    Li, Z.; Li, C.J.

    1996-04-01

    High dose (> 200 Mrad) {gamma}-radiation induced displacement damage (or bulk damage) in high resistivity (6--10 k{Omega}-cm) silicon detectors has been studied. It has been found that detector bulk leakage current increases with {gamma} dose at a rate of 3.3 {times} 10{sup {minus}7} A/cm{sup 3}/Mrad. This introduction rate of bulk leakage current makes the introduction of generation centers by 210 Mrad of {gamma}-radiation comparable to that by 1 {times} 10{sup 12} n/cm{sup 2} of neutron radiation. Significant carrier removal (or donor removal), about 100%, was found in detectors irradiated to 215 Mrad. Space charge sign inversion (SCSI) (or type inversion) was observed in detectors irradiated to {ge} 215 Mrad using transient current technique (TCT). As many as seven deep levels have been observed by current deep level transient spectroscopy (I-DLTS). There was little or no annealing (or reverse annealing) for detectors irradiated to 215 Mrad. Some annealing for detectors irradiated to 500 Mrad have been observed.

  16. Three-dimensional imaging of human hippocampal tissue using synchrotron radiation- and grating-based micro computed tomography

    NASA Astrophysics Data System (ADS)

    Hieber, Simone E.; Khimchenko, Anna; Kelly, Christopher; Mariani, Luigi; Thalmann, Peter; Schulz, Georg; Schmitz, Rüdiger; Greving, Imke; Dominietto, Marco; Müller, Bert

    2014-09-01

    Hippocampal sclerosis is a common cause of epilepsy, whereby a neuronal cell loss of more than 50% cells is characteristic. If medication fails the best possible treatment is the extraction of the diseased organ. To analyze the microanatomy of the diseased tissue we scanned a human hippocampus extracted from an epilepsy patient. After the identification of degenerated tissue using magnetic resonance imaging the specimen was reduced in size to fit into a cylindrical container with a diameter of 6 mm. Using synchrotron radiation and grating interferometry we acquired micro computed tomography datasets of the specimen. The present study was one of the first successful phase tomography measurements at the imaging beamline P05 (operated by HZG at the PETRA III storage ring, DESY, Hamburg, Germany). Ring and streak artefacts were reduced by enhanced flat-field corrections, combined wavelet-Fourier filters and bilateral filtering. We improved the flat-field correction by the consideration of the correlation between the projections and the flat-field images. In the present study, the correlation that was based on mean squared differences and evaluated on manually determined reference regions leads to the best artefact reduction. A preliminary segmentation of the abnormal tissue reveals that a clinically relevant study requires the development of even more sophisticated artifact reduction tools or a phase contrast measurement of higher quality.

  17. Signatures of asymmetry in neutron spectra and images predicted by three-dimensional radiation hydrodynamics simulations of indirect drive implosions

    NASA Astrophysics Data System (ADS)

    Chittenden, J. P.; Appelbe, B. D.; Manke, F.; McGlinchey, K.; Niasse, N. P. L.

    2016-05-01

    We present the results of 3D simulations of indirect drive inertial confinement fusion capsules driven by the "high-foot" radiation pulse on the National Ignition Facility. The results are post-processed using a semi-deterministic ray tracing model to generate synthetic deuterium-tritium (DT) and deuterium-deuterium (DD) neutron spectra as well as primary and down scattered neutron images. Results with low-mode asymmetries are used to estimate the magnitude of anisotropy in the neutron spectra shift, width, and shape. Comparisons of primary and down scattered images highlight the lack of alignment between the neutron sources, scatter sites, and detector plane, which limits the ability to infer the ρr of the fuel from a down scattered ratio. Further calculations use high bandwidth multi-mode perturbations to induce multiple short scale length flows in the hotspot. The results indicate that the effect of fluid velocity is to produce a DT neutron spectrum with an apparently higher temperature than that inferred from the DD spectrum and which is also higher than the temperature implied by the DT to DD yield ratio.

  18. Three dimensional location of internal mammary lymph nodes (IMLN) in patients undergoing radiation therapy: Implications for portal planning

    SciTech Connect

    Kaplan, W.D.; Anderson, J.W.; Siddon, R.L.; Connolly, B.T.; McCormick, C.A.; Laffin, S.M.; Rosenbaum, E.M.; Jennings, C.A.; Harris, J.R.

    1985-05-01

    In breast cancer patients (pts.), radiation therapy (RT) techniques must account for individual anatomy to ensure optimal coverage of tumor regions. Knowledge of IMLN localization is often useful when tangential or anterior (AP) portals are used. We have analyzed IMLN localization in 167 pts. who had lymphoscintigraphy (LS) for RT planning. Parallel and slant-hole collimation were used for imaging. Ribs were defined with lead markers, and a chest x-ray was taken to localize marker positions. Rib and interspace (IS) location of each node was recorded. 768 nodes were analyzed for position and RT coverage (Rib 1-IS 5). The X-bar number of nodes was 4/6 pt. with no significant difference in number by age. Cross-over to the opposite IMLN chain occurred in 13.8% of cases (56.5% manubrial, 17.4% midsternal, and 26.1% xiphoid). With nodes in the idealized tangential field (those from IS 2-5, anterior to a 35/sup 0/ plane entering the thorax 3 cm contralateral to midline, at least one node could have been missed in 31 pts. (18.6%), represented by 44 of 768 nodes (5.7%). In conclusion, RT portals based on ''idealized pts.'' can result in both over and undertreated nodes; LS will obviate this and provide data for individualized treatment planning.

  19. Signatures of asymmetry in neutron spectra and images predicted by three-dimensional radiation hydrodynamics simulations of indirect drive implosions

    SciTech Connect

    Chittenden, J. P. Appelbe, B. D.; Manke, F.; McGlinchey, K.; Niasse, N. P. L.

    2016-05-15

    We present the results of 3D simulations of indirect drive inertial confinement fusion capsules driven by the “high-foot” radiation pulse on the National Ignition Facility. The results are post-processed using a semi-deterministic ray tracing model to generate synthetic deuterium-tritium (DT) and deuterium-deuterium (DD) neutron spectra as well as primary and down scattered neutron images. Results with low-mode asymmetries are used to estimate the magnitude of anisotropy in the neutron spectra shift, width, and shape. Comparisons of primary and down scattered images highlight the lack of alignment between the neutron sources, scatter sites, and detector plane, which limits the ability to infer the ρr of the fuel from a down scattered ratio. Further calculations use high bandwidth multi-mode perturbations to induce multiple short scale length flows in the hotspot. The results indicate that the effect of fluid velocity is to produce a DT neutron spectrum with an apparently higher temperature than that inferred from the DD spectrum and which is also higher than the temperature implied by the DT to DD yield ratio.

  20. Comparison of intensity-modulated radiotherapy with three-dimensional conformal radiation therapy planning for glioblastoma multiforme

    SciTech Connect

    Chan, Maria F.; Schupak, Karen; Burman, Chandra; Chui, C.-S.; Ling, C. Clifton

    2003-12-31

    This study was designed to assess the feasibility and potential benefit of using intensity-modulated radiotherapy (IMRT) planning for patients newly diagnosed with glioblastoma multiforme (GBM). Five consecutive patients with confirmed histopathologically GBM were entered into the study. These patients were planned and treated with 3-dimensional conformal radiation therapy (3DCRT) using our standard plan of 3 noncoplanar wedged fields. They were then replanned with the IMRT method that included a simultaneous boost to the gross tumor volume (GTV). The dose distributions and dose-volume histograms (DHVs) for the planning treatment volume (PTV), GTV, and the relevant critical structures, as obtained with 3DCRT and IMRT, respectively, were compared. In both the 3DCRT and IMRT plans, 59.4 Gy was delivered to the GTV plus a margin of 2.5 cm, with doses to critical structures below the tolerance threshold. However, with the simultaneous boost in IMRT, a higher tumor dose of {approx}70 Gy could be delivered to the GTV, while still maintaining the uninvolved brain at dose levels of the 3DCRT technique. In addition, our experience indicated that IMRT planning is less labor intensive and time consuming than 3DCRT planning. Our study shows that IMRT planning is feasible and efficient for radiotherapy of GBM. In particular, IMRT can deliver a simultaneous boost to the GTV while better sparing the normal brain and other critical structures.

  1. High-dose Neural Stem Cell Radiation May Not Improve Survival in Glioblastoma.

    PubMed

    Achari, R; Arunsingh, M; Badgami, R K; Saha, A; Chatterjee, S; Shrimali, R K; Mallick, I; Arun, B

    2017-06-01

    To evaluate the effect of radiotherapy dose-volume parameters of neural stem cell (NSC) compartment on progression-free survival (PFS) and overall survival after post-resection chemoradiation in newly diagnosed glioblastoma. Sixty-one patients with unifocal glioblastoma were included. Ipsilateral (NSC_Ipsi), contralateral (NSC_Contra) and combined NSC (NSC_Combined) were contoured on radiotherapy planning computerised tomography datasets. NSC dose-volume parameters were correlated with PFS and overall survival. Serial magnetic resonance imaging scans were assessed to understand the frequency of pre- and post-treatment involvement of the NSC by contrast enhancing lesions (CELs). Baseline involvement of NSC with CELs was seen in 67.2% and 95.9% had CELs and FLAIR abnormalities at progression. With a median follow-up of 14.1 months (interquartile range 9.4-20.6 months), median PFS and overall survival were 14.5 (95% confidence interval 11.6-17.5) and 16.2 (95% confidence interval 13.3-19.2) months, respectively. Poor Eastern Cooperative Oncology Group performance score, advanced recursive partitioning analysis class, unmethylated O6-methylguanine methyltransferase (MGMT) status, higher than median of mean NSC_Ipsi dose were associated with significantly inferior PFS and overall survival on univariate analysis. On multivariate analysis, unmethylated MGMT status, higher than median of mean doses to NSC_Ipsi and poor compliance to adjuvant temozolomide were independent predictors of inferior survival. In this cohort, 67.2% of newly diagnosed glioblastoma patients had NSC involved with CELs at presentation and 95.9% at progression. This might be an imaging surrogate of the current notion of gliomagenesis and progression from NSC rests. A high radiation dose to NSC_Ipsi was significantly associated with inferior survival. This could be a function of larger tumours and planning target volumes in those with pre-treatment NSC involvement. Methylated MGMT and good compliance

  2. The Effect of High-Dose Ionizing Radiation on the Isolated Photobiont of the Astrobiological Model Lichen Circinaria gyrosa

    NASA Astrophysics Data System (ADS)

    Meeßen, Joachim; Backhaus, Theresa; Brandt, Annette; Raguse, Marina; Böttger, Ute; de Vera, Jean-Pierre; de la Torre, Rosa

    2017-02-01

    Lichen symbioses between fungi and algae represent successful life strategies to colonize the most extreme terrestrial habitats. Consequently, space exposure and simulation experiments have demonstrated lichens' high capacity for survival, and thus, they have become models in astrobiological research with which to discern the limits and limitations of terrestrial life. In a series of ground-based irradiation experiments, the STARLIFE campaign investigated the resistance of astrobiological model organisms to galactic cosmic radiation, which is one of the lethal stressors of extraterrestrial environments. Since previous studies have identified that the alga is the more sensitive lichen symbiont, we chose the isolated photobiont Trebouxia sp. of the astrobiological model Circinaria gyrosa as a subject in the campaign. Therein, γ radiation was used to exemplify the deleterious effects of low linear energy transfer (LET) ionizing radiation at extremely high doses up to 113 kGy in the context of astrobiology. The effects were analyzed by chlorophyll a fluorescence of photosystem II (PSII), cultivation assays, live/dead staining and confocal laser scanning microscopy (CLSM), and Raman laser spectroscopy (RLS). The results demonstrate dose-dependent impairment of photosynthesis, the cessation of cell proliferation, cellular damage, a decrease in metabolic activity, and degradation of photosynthetic pigments. While previous investigations on other extraterrestrial stressors have demonstrated a high potential of resistance, results of this study reveal the limits of photobiont resistance to ionizing radiation and characterize γ radiation-induced damages. This study also supports parallel STARLIFE studies on the lichens Circinaria gyrosa and Xanthoria elegans, both of which harbor a Trebouxia sp. photobiont.

  3. Pulmonary Artery Invasion, High-Dose Radiation, and Overall Survival in Patients With Non-Small Cell Lung Cancer

    SciTech Connect

    Han, Cheng-Bo; Wang, Wei-Li; Quint, Leslie; Xue, Jian-Xin; Matuszak, Martha; Ten Haken, Randall; Kong, Feng-Ming

    2014-06-01

    Purpose: To investigate whether high-dose radiation to the pulmonary artery (PA) affects overall survival (OS) in patients with non-small cell lung cancer (NSCLC). Methods and Materials: Patients with medically inoperable/unresectable NSCLC treated with definitive radiation therapy in prospective studies were eligible for this study. Pulmonary artery involvement was defined on the basis of pretreatment chest CT and positron emission tomography/CT fusion. Pulmonary artery was contoured according to the Radiation Therapy Oncology Group protocol 1106 atlas, and dose-volume histograms were generated. Results: A total of 100 patients with a minimum follow-up of 1 year for surviving patients were enrolled: 82.0% underwent concurrent chemoradiation therapy. Radiation dose ranged from 60 to 85.5 Gy in 30-37 fractions. Patients with PA invasion of grade ≤2, 3, 4, and 5 had 1-year OS and median survival of 67% and 25.4 months (95% confidence interval [CI] 15.7-35.1), 62% and 22.2 months (95% CI 5.8-38.6), 90% and 35.8 months (95% CI 28.4-43.2), and 50% and 7.0 months, respectively (P=.601). Two of the 4 patients with grade 5 PA invasion died suddenly from massive hemorrhage at 3 and 4.5 months after completion of radiation therapy. Maximum and mean doses to PA were not significantly associated with OS. The V45, V50, V55, and V60 of PA were correlated significantly with a worse OS (P<.05). Patients with V45 >70% or V60 >37% had significantly worse OS (13.3 vs 37.9 months, P<.001, and 13.8 vs 37.9 months, P=.04, respectively). Conclusions: Grade 5 PA invasion and PA volume receiving more than 45-60 Gy may be associated with inferior OS in patients with advanced NSCLC treated with concurrent chemoradiation.

  4. Ex vivo cultures of glioblastoma in three-dimensional hydrogel maintain the original tumor growth behavior and are suitable for preclinical drug and radiation sensitivity screening

    SciTech Connect

    Jiguet Jiglaire, Carine; Baeza-Kallee, Nathalie; Denicolaï, Emilie; Barets, Doriane; Metellus, Philippe; and others

    2014-02-15

    Identification of new drugs and predicting drug response are major challenges in oncology, especially for brain tumors, because total surgical resection is difficult and radiation therapy or chemotherapy is often ineffective. With the aim of developing a culture system close to in vivo conditions for testing new drugs, we characterized an ex vivo three-dimensional culture system based on a hyaluronic acid-rich hydrogel and compared it with classical two-dimensional culture conditions. U87-MG glioblastoma cells and seven primary cell cultures of human glioblastomas were subjected to radiation therapy and chemotherapy drugs. It appears that 3D hydrogel preserves the original cancer growth behavior and enables assessment of the sensitivity of malignant gliomas to radiation and drugs with regard to inter-tumoral heterogeneity of therapeutic response. It could be used for preclinical assessment of new therapies. - Highlights: • We have compared primary glioblastoma cell culture in a 2D versus 3D-matrix system. • In 3D morphology, organization and markers better recapitulate the original tumor. • 3D-matrix culture might represent a relevant system for more accurate drug screening.

  5. Laser-guided direct writing for three-dimensional tissue engineering: Analysis and application of radiation forces

    NASA Astrophysics Data System (ADS)

    Nahmias, Yaakov Koby

    Tissue Engineering aims for the creation of functional tissues or organs using a combination of biomaterials and living cells. Artificial tissues can be implanted in patients to restore tissue function that was lost due to trauma, disease, or genetic disorder. Tissue equivalents may also be used to screen the effects of drugs and toxins, reducing the use of animals in research. One of the principle limitations to the size of engineered tissue is oxygen and nutrient transport. Lacking their own vascular bed, cells embedded in the engineered tissue will consume all available oxygen within hours while out branching blood vessels will take days to vascularize the implanted tissue. Establishing capillaries within the tissue prior to implantation can potentially eliminate this limitation. One approach to establishing capillaries within the tissue is to directly write endothelial cells with micrometer accuracy as it is being built. The patterned endothelial cells will then self-assemble into vascular structures within the engineering tissue. The cell patterning technique known as laser-guided direct writing can confine multiple cells in a laser beam and deposit them as a steady stream on any non-absorbing surface with micrometer scale accuracy. By applying the generalized Lorenz-Mie theory for light scattering on laser-guided direct writing we were able to accurately predict the behavior of with various cells and particles in the focused laser. In addition, two dimensionless parameters were identified for general radiation-force based system design. Using laser-guided direct writing we were able to direct the assembly of endothelial vascular structures with micrometer accuracy in two and three dimensions. The patterned vascular structures provided the backbone for subsequent in vitro liver morphogenesis. Our studies show that hepatocytes migrate toward and adhere to endothelial vascular structures in response to endothelial-secreted hepatocyte growth factor (HGF). Our

  6. Wireless and chip-less passive radiation sensors for high dose monitoring

    SciTech Connect

    Debourg, E.; Aubert, H.; Pons, P.; Augustyniak, I.; Knapkiewicz, P.; Dziuban, J.; Matusiak, M.; Olszacki, M.

    2015-07-01

    The safety of nuclear infrastructures may involve the monitoring of many parameters in harsh environments (high radiation level, high temperature, high pressure,..). If technological solutions exist for transducers part in such environments, the electronic part used in reader is not appropriate and still a challenging task. Well-known solutions to remove the electronic part from the harsh environment consist of connecting the transducer and the reader by long electrical wires or performing ex situ remote sensing. However wires may practically be difficult to implement while ex situ measurements are not compatible with on line monitoring. Wireless and passive sensors working in harsh environments could be an appropriate solution for the remote sensing of critical parameters. Passive sensors without electronics in the sensing unit are available (e.g., SAW sensors) but they suffer from short reading range (typically lower than 10 meters). In order to overcome this range limitation a new class of electromagnetic transducers was developed in the mid-2000's. The operating principle is based on the modification of the properties of high-frequency (>> 1 GHz) passive electromagnetic devices by the quantity to be measured. Based on this principle a wide range of sensing properties can be addressed and a large number of materials can be chosen. Moreover the use of high frequency allows reducing the size of the sensor elements (antenna, transducer) and enhancing the immunity to multi-path. Several principles of RF transducers have been already validated by LAAS-CNRS (e;g; pressure, temperature, stress) as well as radar-based solution for the wireless long-range sensors interrogation. The sensor dosimeter exploit here the known property of Hydrogen-Pressure Dosimeters (HPD) for which the polymer material dehydrogenates under nuclear irradiation. The transducer principle is described. The irradiation will generate the out-gazing (hydrogen) of the polymer inside a micro

  7. Upregulated epidermal growth factor receptor expression following near-infrared irradiation simulating solar radiation in a three-dimensional reconstructed human corneal epithelial tissue culture model

    PubMed Central

    Tanaka, Yohei; Nakayama, Jun

    2016-01-01

    Background and objective Humans are increasingly exposed to near-infrared (NIR) radiation from both natural (eg, solar) and artificial (eg, electrical appliances) sources. Although the biological effects of sun and ultraviolet (UV) exposure have been extensively investigated, the biological effect of NIR radiation is still unclear. We previously reported that NIR as well as UV induces photoaging and standard UV-blocking materials, such as sunglasses, do not sufficiently block NIR. The objective of this study was to investigate changes in gene expression in three-dimensional reconstructed corneal epithelial tissue culture exposed to broad-spectrum NIR irradiation to simulate solar NIR radiation that reaches human tissues. Materials and methods DNA microarray and quantitative real-time polymerase chain reaction analysis were used to assess gene expression levels in a three-dimensional reconstructed corneal epithelial model composed of normal human corneal epithelial cells exposed to water-filtered broad-spectrum NIR irradiation with a contact cooling (20°C). The water-filter allowed 1,000–1,800 nm wavelengths and excluded 1,400–1,500 nm wavelengths. Results A DNA microarray with >62,000 different probes showed 25 and 150 genes that were up- or downregulated by at least fourfold and twofold, respectively, after NIR irradiation. In particular, epidermal growth factor receptor (EGFR) was upregulated by 19.4-fold relative to control cells. Quantitative real-time polymerase chain reaction analysis revealed that two variants of EGFR in human corneal epithelial tissue were also significantly upregulated after five rounds of 10 J/cm2 irradiation (P<0.05). Conclusion We found that NIR irradiation induced the upregulated expression of EGFR in human corneal cells. Since over half of the solar energy reaching the Earth is in the NIR region, which cannot be adequately blocked by eyewear and thus can induce eye damage with intensive or long-term exposure, protection from both

  8. Development and Testing of Gallium Arsenide Photoconductive Detectors for Ultra Fast, High Dose Rate Pulsed Electron and Bremsstrahlung Radiation Measurements

    SciTech Connect

    Kharashvili, George; Makarashvili, Vakhtang; Mitchell, Marc; Beezhold, Wendland; Spaulding, Randy; Wells, Douglas; Gesell, Thomas; Wingert, Wayne

    2009-03-10

    Real time radiation dose measurements are challenging in high dose rate environments such as those used for testing electronic devices or biological agents. Dosimetry needs in pulsed reactor fields and particle accelerator facilities require development of dosimeters with fast (10 s of picoseconds) response to pulsed radiation, linear response over a wide range of dose rates (up to 10{sup 11} Gy/s), high resistance to radiation damage, and successful operation in mixed gamma and neutron environments. Gallium arsenide photoconductive detectors (GaAs PCD) have been shown to exhibit many of these desirable characteristics, especially fast time response. Less than 50 ps time resolution has been demonstrated when previously irradiated by fission neutrons. We have conducted a study of the response-time dependence on neutron fluence, starting with fluences at {approx}10{sup 14} n/cm{sup 2}. A 23-MeV electron beam was used to produce photoneutrons in a tungsten target for irradiation of a GaAs wafer from which PCDs were made. The process was modeled using MCNPX computer code and the simulation results were compared to the experimental measurements. GaAs PCDs were fabricated from both neutron-irradiated and non-irradiated GaAs samples. The results of the preliminary tests of these devices in accelerator-produced pulses of electron and bremsstrahlung radiation of various energies (13 to 35 MeV) and pulse lengths (100 ps to 4 {mu}s) are presented together with an overview of the future plans of continuing GaAs PCD research at Idaho State University.

  9. Three Dimensional Visualization of Human Cardiac Conduction Tissue in Whole Heart Specimens by High-Resolution Phase-Contrast CT Imaging Using Synchrotron Radiation.

    PubMed

    Shinohara, Gen; Morita, Kiyozo; Hoshino, Masato; Ko, Yoshihiro; Tsukube, Takuro; Kaneko, Yukihiro; Morishita, Hiroyuki; Oshima, Yoshihiro; Matsuhisa, Hironori; Iwaki, Ryuma; Takahashi, Masashi; Matsuyama, Takaaki; Hashimoto, Kazuhiro; Yagi, Naoto

    2016-11-01

    The feasibility of synchrotron radiation-based phase-contrast computed tomography (PCCT) for visualization of the atrioventricular (AV) conduction axis in human whole heart specimens was tested using four postmortem structurally normal newborn hearts obtained at autopsy. A PCCT imaging system at the beamline BL20B2 in a SPring-8 synchrotron radiation facility was used. The PCCT imaging of the conduction system was performed with "virtual" slicing of the three-dimensional reconstructed images. For histological verification, specimens were cut into planes similar to the PCCT images, then cut into 5-μm serial sections and stained with Masson's trichrome. In PCCT images of all four of the whole hearts of newborns, the AV conduction axis was distinguished as a low-density structure, which was serially traceable from the compact node to the penetrating bundle within the central fibrous body, and to the branching bundle into the left and right bundle branches. This was verified by histological serial sectioning. This is the first demonstration that visualization of the AV conduction axis within human whole heart specimens is feasible with PCCT. © The Author(s) 2016.

  10. Similarity solution to three dimensional boundary layer flow of second grade nanofluid past a stretching surface with thermal radiation and heat source/sink

    SciTech Connect

    Hayat, T.; Muhammad, Taseer; Shehzad, S. A.; Alsaedi, A.

    2015-01-15

    Development of human society greatly depends upon solar energy. Heat, electricity and water from nature can be obtained through solar power. Sustainable energy generation at present is a critical issue in human society development. Solar energy is regarded one of the best sources of renewable energy. Hence the purpose of present study is to construct a model for radiative effects in three-dimensional of nanofluid. Flow of second grade fluid by an exponentially stretching surface is considered. Thermophoresis and Brownian motion effects are taken into account in presence of heat source/sink and chemical reaction. Results are derived for the dimensionless velocities, temperature and concentration. Graphs are plotted to examine the impacts of physical parameters on the temperature and concentration. Numerical computations are presented to examine the values of skin-friction coefficients, Nusselt and Sherwood numbers. It is observed that the values of skin-friction coefficients are more for larger values of second grade parameter. Moreover the radiative effects on the temperature and concentration are quite reverse.

  11. Phase 2 trial of radiation plus high-dose tamoxifen for glioblastoma multiforme: RTOG protocol BR-00211

    PubMed Central

    Robins, H. Ian; Won, M.; Seiferheld, Wendy F.; Schultz, Christopher J.; Choucair, Ali K.; Brachman, David G.; Demas, William F.; Mehta, Minesh P.

    2006-01-01

    Preclinical studies support the concept that inhibition of protein kinase C (PKC) by tamoxifen (TAM) should provide both antineoplastic effects and radiosensitization. High-dose TAM (80 mg/m2 p.o. daily in divided doses) was given with and after conventional radiotherapy (XRT) to inhibit PKC-mediated signaling, which is known to be enhanced in glioblastoma (GBM). Seventy-seven patients were accrued between December 2000 and December 2001; two were ineligible and not included in the efficacy results. Pretreatment characteristics of the patients included the following: 52% were less than 60 years of age, 39% had a Zubrod score of 0, 70% had minor or no neurological symptoms, and 65% were Radiation Therapy Oncology Group–recursive partition analysis (RPA) class III and IV. Eighty-six percent of patients achieved acceptable dosing of TAM. Notable toxicity included late radiation grade 3 in two patients and thromboembolic events in 16 patients (two grade 2, 10 grade 3, three grade 4, and one grade 5), for an incidence of 20.8% (which is lower than expected, based on the literature for deep vein thrombophlebitis in GBM patients not receiving TAM). Median survival time (MST) was 9.7 months as compared (by three different statistical methodologies) to the historical GBM control database of 1457 RPA class III, IV, and V drug/ XRT-treated patients. After controlling for RPA class IV, the MST was 11.3 months, which compares to the historical RPA control of 11.3 months (P = 0.37). The results obtained do not exhibit a substantial advance over those of previous studies with various XRT/drug doublets, including BCNU. However, as TAM does not have significant overlapping toxicities with most other drugs, its testing in a combined modality approach with other medications may be justified in future clinical trials. Historically, the incidence of thromboembolic events in GBM patients is approximately 30%. The lower-than-expected incidence seen here has also been observed in other

  12. WE-E-BRE-06: High-Dose Microbeam Radiation Induces Different Responses in Tumor Microenvironment Compared to Conventional Seamless Radiation in Window Chamber Tumor Models

    SciTech Connect

    Chang, S; Zhang, J; Hadsell, M; Fontanella, A; Schroeder, T; Palmer, G; Dewhirst, M; Boss, M; Berman, K

    2014-06-15

    Purpose: Microbeam radiation therapy and GRID therapy are different forms of Spatially-Fractioned Radiation Therapy (SFRT) that is fundamentally different from the conventional seamless and temporally fractionated radiation therapy. SFRT is characterized by a ultra-high dose (10s –100s Gy) dose single treatment with drastic inhomogeneity pattern of given spatial frequencies. Preclinical and limited clinical studies have shown that the SFRT treatments may offer significant improvements in reducing treatment toxicity, especially for those patients who have not benefited from the state-of-the-art radiation therapy approaches. This preliminary study aims to elucidate the underlying working mechanisms of SFRT, which currently remains poorly understood. Methods: A genetically engineered 4T1 murine mammary carcinoma cell line and nude mice skin fold window chamber were used. A nanotechnology-based 160kV x-ray irradiator delivered 50Gy (entrance dose) single treatments of microbeam or seamless radiation. Animals were in 3 groups: mock, seamless radiation, and 300μm microbeam radiation. The windows were imaged using a hyperspectral system to capture total hemoglobin/saturation, GFP fluorescence emission, RFP fluorescence emission, and vessel density at 9 time points up to 7 days post radiation. Results: We found unique physiologic changes in different tumor/normal tissue regions and differential effects between seamless and microbeam treatments. They include 1) compared to microbeam and mock radiation seamless radiation damaged more microvasculature in tumor-surrounding normal tissue, 2) a pronounced angiogenic effect was observed with vascular proliferation in the microbeam irradiated portion of the tumor days post treatment (no such effect observed in seamless and mock groups), and 3) a notable change in tumor vascular orientation was observed where vessels initially oriented parallel to the beam length were replaced by vessels running perpendicular to the irradiation

  13. Black carbon simulations using a size- and mixing-state-resolved three-dimensional model: 1. Radiative effects and their uncertainties

    NASA Astrophysics Data System (ADS)

    Matsui, H.

    2016-02-01

    This study quantifies how uncertainties in the size distribution and mixing state parameters of black carbon (BC) emissions translate into the uncertainties in BC radiative effects by using a particle-size- and mixing-state-resolved three-dimensional model, the Weather Research and Forecasting model with chemistry (WRF-chem) with the Aerosol Two-dimensional bin module for foRmation and Aging Simulation (ATRAS) and the Model for Simulating Aerosol Interactions and Chemistry (MOSAIC). The WRF-chem/ATRAS-MOSAIC model can explicitly calculate BC processes in the atmosphere, such as BC aging due to condensation and coagulation and the resulting enhancement of absorption and cloud condensation nuclei activity, with 12 size and 10 BC mixing state bins (128 bins in total). Fifteen model simulations perturbing the emission parameters within their uncertainties are conducted over East Asia (spring 2009) to understand which parameters and processes are important and which are associated with the uncertainty in evaluating BC radiative effects. The simulations reveal a large variability (uncertainty) of BC optical and radiative variables over the East Asian region (the variability is 58-99%), which corresponds to ranges of BC radiative effect of 1.6-2.8 W m-2 at the top of the atmosphere and from -5.2 to -2.1 W m-2 at the surface over East Asia. BC optical and radiative variables are 3 to 5 times sensitive to the size and the mixing state in emissions than BC mass concentrations (the variability is 20%). The two main causes of the difference in sensitivity are the reduction of the variability of BC mass concentrations by coagulation and the enhancement of the variability of BC absorption by resolving BC mixing state. These complicated responses of aerosol processes can be calculated for the first time using a detailed aerosol model such as ATRAS. The results suggest that the following two points are important in the estimation of BC radiative effects: (1) reduction of the

  14. Three-dimensional nanomagnetism

    DOE PAGES

    Fernandez-Pacheco, Amalio; Streubel, Robert; Fruchart, Olivier; ...

    2017-06-09

    Magnetic nanostructures are being developed for use in many aspects of our daily life, spanning areas such as data storage, sensing and biomedicine. Whereas patterned nanomagnets are traditionally two-dimensional planar structures, recent work is expanding nanomagnetism into three dimensions; a move triggered by the advance of unconventional synthesis methods and the discovery of new magnetic effects. In three-dimensional nanomagnets more complex magnetic configurations become possible, many with unprecedented properties. Here we review the creation of these structures and their implications for the emergence of new physics, the development of instrumentation and computational methods, and exploitation in numerous applications.

  15. Three dimensional quantum chromodynamics

    NASA Astrophysics Data System (ADS)

    Ferretti, G.; Rajeev, S. G.; Yang, Z.

    1992-02-01

    The subject of this talk is the study of the low energy behavior of three (2+1) dimensional Quantum Chromodynamics. We show the existence of a phase where parity is unbroken and the flavor group U(2n) is broken into a subgroup U(n)×U(n). We derive the low energy effective action for the theory and show that it has solitonic excitations with Fermi statistic, to be identified with the three dimensional ``baryon''. Finally, we study the current algebra for this effective action and we find a co-homologically nontrivial generalization of Kac-Moody algebras to three dimension.

  16. Three-dimensional metamaterials

    SciTech Connect

    Burckel, David Bruce

    2012-06-12

    A fabrication method is capable of creating canonical metamaterial structures arrayed in a three-dimensional geometry. The method uses a membrane suspended over a cavity with predefined pattern as a directional evaporation mask. Metallic and/or dielectric material can be evaporated at high vacuum through the patterned membrane to deposit resonator structures on the interior walls of the cavity, thereby providing a unit cell of micron-scale dimension. The method can produce volumetric metamaterial structures comprising layers of such unit cells of resonator structures.

  17. Three-dimensional nanomagnetism

    NASA Astrophysics Data System (ADS)

    Fernández-Pacheco, Amalio; Streubel, Robert; Fruchart, Olivier; Hertel, Riccardo; Fischer, Peter; Cowburn, Russell P.

    2017-06-01

    Magnetic nanostructures are being developed for use in many aspects of our daily life, spanning areas such as data storage, sensing and biomedicine. Whereas patterned nanomagnets are traditionally two-dimensional planar structures, recent work is expanding nanomagnetism into three dimensions; a move triggered by the advance of unconventional synthesis methods and the discovery of new magnetic effects. In three-dimensional nanomagnets more complex magnetic configurations become possible, many with unprecedented properties. Here we review the creation of these structures and their implications for the emergence of new physics, the development of instrumentation and computational methods, and exploitation in numerous applications.

  18. Direct 2-Arm Comparison Shows Benefit of High-Dose-Rate Brachytherapy Boost vs External Beam Radiation Therapy Alone for Prostate Cancer

    SciTech Connect

    Khor, Richard; Duchesne, Gillian; Tai, Keen-Hun; Foroudi, Farshad; Chander, Sarat; Van Dyk, Sylvia; Garth, Margaret; Williams, Scott

    2013-03-01

    Purpose: To evaluate the outcomes of patients treated for intermediate- and high-risk prostate cancer with a single schedule of either external beam radiation therapy (EBRT) and high-dose-rate brachytherapy (HDRB) boost or EBRT alone. Methods and Materials: From 2001-2006, 344 patients received EBRT with HDRB boost for definitive treatment of intermediate- or high-risk prostate cancer. The prescribed EBRT dose was 46 Gy in 23 fractions, with a HDR boost of 19.5 Gy in 3 fractions. This cohort was compared to a contemporaneously treated cohort who received EBRT to 74 Gy in 37 fractions, using a matched pair analysis. Three-dimensional conformal EBRT was used. Matching was performed using a propensity score matching technique. High-risk patients constituted 41% of the matched cohorts. Five-year clinical and biochemical outcomes were analyzed. Results: Initial significant differences in prognostic indicators between the unmatched treatment cohorts were rendered negligible after matching, providing a total of 688 patients. Median biochemical follow-up was 60.5 months. The 5-year freedom from biochemical failure was 79.8% (95% confidence interval [CI], 74.3%-85.0%) and 70.9% (95% CI, 65.4%-76.0%) for the HDRB and EBRT groups, respectively, equating to a hazard ratio of 0.59 (95% CI, 0.43-0.81, P=.0011). Interaction analyses showed no alteration in HDR efficacy when planned androgen deprivation therapy was administered (P=.95), but a strong trend toward reduced efficacy was shown compared to EBRT in high-risk cases (P=.06). Rates of grade 3 urethral stricture were 0.3% (95% CI, 0%-0.9%) and 11.8% (95% CI, 8.1%-16.5%) for EBRT and HDRB, respectively (P<.0001). No differences in clinical outcomes were observed. Conclusions: This comparison of 2 individual contemporaneously treated HDRB and EBRT approaches showed improved freedom from biochemical progression with the HDR approach. The benefit was more pronounced in intermediate- risk patients but needs to be weighed against

  19. Dosimetric Comparison of High-Dose-Rate Brachytherapy and Intensity-Modulated Radiation Therapy as a Boost to the Prostate

    SciTech Connect

    Hermesse, Johanne; Biver, Sylvie; Jansen, Nicolas; Lenaerts, Eric; Nickers, Philippe

    2010-01-15

    Purpose: We compared the dose conformity of two radiation modalities: high-dose-rate brachytherapy (HDR BT) and intensity-modulated radiation therapy (IMRT) to deliver a boost to the prostate after external beam radiotherapy (EBRT). Methods and Materials: Ten successive patients with prostate adenocarcinoma treated with a single 10-Gy HDR BT boost after EBRT were investigated. Four theoretical IMRT plans were computed: (a) 32.85 Gy IMRT and (b) 26 Gy IMRT with CTV-PTV expansions, doses corresponding to the equivalent dose in 2-Gy fractions (EQD2) of one 10-Gy fraction calculated with a prostate alpha/beta ratio of respectively 1.5 and 3 Gy; and (c) 32.85 Gy IMRT and (d) 26 Gy IMRT without CTV-PTV expansions. The dose-volume histogram values converted in EQD2 with an alpha/beta ratio of 3 Gy for the organs at risk were compared. Results: The HDR BT plan delivered higher mean doses to the PTV compared with IMRT plans. In all, 33% of the rectal volume received a mean dose of 5.32 +- 0.65 Gy and 20% of bladder volume received 4.61 +- 1.24 Gy with HDR BT. In comparison, doses delivered with IMRT were respectively 13.4 +- 1.49 Gy and 10.81 +- 4 Gy, even if only 26 Gy was prescribed to the PTV with no CTV-PTV expansion (p < 0.0001). The hot spots inside the urethra were greater with HDR BT but acceptable. Conclusions: Use of HDR BT produced a more conformal plan for the boost to the prostate than IMRT even without CTV-PTV expansions.

  20. Pulmonary Artery Invasion, High Dose Radiation, and Overall Survival in Patients with Non-Small Cell Lung Cancer

    PubMed Central

    Han, Cheng-Bo; Wang, Wei-Li; Quint, Leslie; Xue, Jian-Xin; Matuszak, Martha; Haken, Randall Ten; Kong, Feng-Ming (Spring)

    2014-01-01

    Purpose This study aimed to investigate whether high dose radiation to the pulmonary artery (PA) affects overall survival (OS) in patients with non-small cell lung cancer (NSCLC). Methods and Materials Patients with medically inoperable/unresectable NSCLC treated with definitive radiotherapy (RT) in prospective studies were eligible for this study. PA involvement was defined on the basis of pre-treatment chest computed tomography (CT) and positron emission tomography CT fusion (PET/CT). PA was contoured according to RTOG 1106 atlas and dose volume histograms were generated. Results A total of 100 patients with a minimum follow-up of 1 year for surviving patients were enrolled: 82.0% underwent concurrent chemoradiotherapy. Radiation dose ranged 60-85.5 Gy in 30-37 fractions. Patients with PA invasion of grade ≤ 2, 3, 4, and 5 had 1-year overall survival and median survival of 67% and 25.4 months (95% CI, 15.7-35.1), 62% and 22.2 months (95% CI, 5.8-38.6), 90% and 35.8 months (95% CI, 28.4-43.2), and 50% and 7.0 months, respectively (P = 0.601). Two of the 4 patients with grade 5 PA invasion died suddenly from massive hemorrhage at 3 and 4.5 months after completion of RT. Maximum and mean doses to PA were not significantly associated with OS. V45, V50, V55, and V60 of PA were correlated significantly with a worse OS (P < 0.05). Patients with V45 > 70%, or V60 > 37% had significantly worse OS (13.3 vs. 37.9 P < 0.001, and 13.8 vs. 37.9 months, P = 0.04, respectively). Conclusions Grade 5 PA invasion and PA volume receiving more than 45-60 Gy may be associated with inferior OS in patients with advanced NSCLC treated with concurrent chemoradiation. PMID:24685448

  1. Three-dimensional registration of synchrotron radiation-based micro-computed tomography images with advanced laboratory micro-computed tomography data from murine kidney casts

    NASA Astrophysics Data System (ADS)

    Thalmann, Peter; Hieber, Simone E.; Schulz, Georg; Deyhle, Hans; Khimchenko, Anna; Kurtcuoglu, Vartan; Olgac, Ufuk; Marmaras, Anastasios; Kuo, Willy; Meyer, Eric P.; Beckmann, Felix; Herzen, Julia; Ehrbar, Stefanie; Müller, Bert

    2014-09-01

    Malfunction of oxygen regulation in kidney and liver may lead to the pathogenesis of chronic diseases. The underlying mechanisms are poorly understood. In kidney, it is hypothesized that renal gas shunting from arteries to veins eliminates excess oxygen. Such shunting is highly dependent on the structure of the renal vascular network. The vascular tree has so far not been quantified under maintenance of its connectivity as three-dimensional imaging of the vessel tree down to the smallest capillaries, which in mouse model are smaller than 5 μm in diameter, is a challenging task. An established protocol uses corrosion casts and applies synchrotron radiation-based micro-computed tomography (SRμCT), which provides the desired spatial resolution with the necessary contrast. However, SRμCT is expensive and beamtime access is limited. We show here that measurements with a phoenix nanotomrm (General Electric, Wunstorf, Germany) can provide comparable results to those obtained with SRμCT, except for regions with small vessel structures, where the signal-to-noise level was significantly reduced. For this purpose the nanotom®m measurement was compared with its corresponding measurement acquired at the beamline P05 at PETRA III at DESY, Hamburg, Germany.

  2. Three Dimensional Dirac Semimetals

    NASA Astrophysics Data System (ADS)

    Zaheer, Saad

    2014-03-01

    Dirac points on the Fermi surface of two dimensional graphene are responsible for its unique electronic behavior. One can ask whether any three dimensional materials support similar pseudorelativistic physics in their bulk electronic spectra. This possibility has been investigated theoretically and is now supported by two successful experimental demonstrations reported during the last year. In this talk, I will summarize the various ways in which Dirac semimetals can be realized in three dimensions with primary focus on a specific theory developed on the basis of representations of crystal spacegroups. A three dimensional Dirac (Weyl) semimetal can appear in the presence (absence) of inversion symmetry by tuning parameters to the phase boundary separating a bulk insulating and a topological insulating phase. More generally, we find that specific rules governing crystal symmetry representations of electrons with spin lead to robust Dirac points at high symmetry points in the Brillouin zone. Combining these rules with microscopic considerations identifies six candidate Dirac semimetals. Another method towards engineering Dirac semimetals involves combining crystal symmetry and band inversion. Several candidate materials have been proposed utilizing this mechanism and one of the candidates has been successfully demonstrated as a Dirac semimetal in two independent experiments. Work carried out in collaboration with: Julia A. Steinberg, Steve M. Young, J.C.Y. Teo, C.L. Kane, E.J. Mele and Andrew M. Rappe.

  3. A direct comparison of a depth-dependent Radiation stress formulation and a Vortex force formulation within a three-dimensional coastal ocean model

    NASA Astrophysics Data System (ADS)

    Moghimi, Saeed; Klingbeil, Knut; Gräwe, Ulf; Burchard, Hans

    2013-10-01

    In this study a model system consisting of the three-dimensional General Estuarine Transport Model (GETM) and the third generation wind wave model SWAN was developed. Both models were coupled in two-way mode. The effects of waves were included into the ocean model by implementing the depth-dependent Radiation stress formulation (RS) of Mellor (2011a) and the Vortex force formulation (VF) presented by Bennis et al. (2011). Thus, the developed model system offers a direct comparison of these two formulations. The enhancement of the vertical eddy viscosity due to the energy transfer by white capping and breaking waves was taken into account by means of injecting turbulent kinetic energy at the surface. Wave-current interaction inside the bottom boundary layer was considered as well. The implementation of both wave-averaged formulations was validated against three flume experiments. One of these experiments with long period surface waves (swell), had not been evaluated before. The validation showed the capability of the model system to reproduce the three-dimensional interaction of waves and currents. For the flume test cases the wave-induced water level changes (wave set-up and set-down) and the corresponding depth-integrated wave-averaged velocities were similar for RS and VF. Both formulations produced comparable velocity profiles for short period waves. However, for large period waves, VF overestimated the wave set-down near the main breaking points and RS showed artificial offshore-directed transport at the surface where wave shoaling was taking place. Finally the validated model system was applied to a realistic barred beach scenario. For RS and VF the resulting velocity profiles were similar after being significantly improved by a roller evolution method. Both wave-averaged formulations generally provided similar results, but some shortcomings were revealed. Although VF partly showed significant deviations from the measurements, its results were still physically

  4. High-dose mode of mortality in Tribolium: A model system for study of radiation injury and repair in non-proliferative tissues

    SciTech Connect

    Cheng, Chihing Christina.

    1989-01-01

    With appropriate doses of ionizing radiation, both the acute, or lethal-midlethal, dose-independent pattern of mortality, and the hyperacute, dose-dependent pattern, were demonstrated within a single insect genus (Tribolium). This demonstration provides resolution of apparently contradictory reports of insect radiation responses in terms of doses required to cause lethality and those based on survival time as a function of dose. A dose-dependent mortality pattern was elicited in adult Tribolium receiving high doses, viz., 300 Gy or greater; its time course was complete in 10 days, before the dose-independent pattern of mortality began. Visual observations of heavily-irradiated Tribolium suggested neural and/or neuromuscular damage, as had been previously proposed by others for lethally-irradiated wasps, flies, and mosquitoes. Results of experiments using fractionated high doses supported the suggestion that the hyperacute or high-dose mode of death is the result of damage to nonproliferative tissues. Relative resistance of a strain to the hyperacute or high-dose mode of death was not correlated with resistance to the midlethal mode, which is believed to be the result of damage to the proliferative cells of the midgut. Using the high-dose mode of death as a model of radiation damage to nonproliferative tissues, the effects of age, and of a moderate priming dose were assessed. Beetles showed age-related increase in sensitivity to the high-dose mode of death, suggesting a decline in capacity to repair radiation damage to postmitotic tissue. This correlated with a decrease (50%) in the amount of repair reflected in the sparing effect of dose-fractionation (SDF) between the age of 1 to 3 months. The age related increase in radiosensitivity was reduced by a moderate priming dose (40 or 65 Gy) given at a young age.

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

    PubMed Central

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

    2016-01-01

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

  6. Late Gastrointestinal Morbidity After Three-Dimensional Conformal Radiation Therapy for Prostate Cancer Fades With Time in Contrast to Genitourinary Morbidity

    SciTech Connect

    Karlsdottir, Asa Muren, Ludvig Paul; Wentzel-Larsen, Tore; Dahl, Olav

    2008-04-01

    Purpose: To investigate the incidence, time course, and relation to irradiated volumes of late morbidity after three-dimensional conformal radiation therapy (RT) for prostate cancer. Methods and Materials: From January 2000 to December 2001, a total of 247 patients with prostate cancer received a target dose of 70 Gy using conformal RT. Forty-eight patients (20%) received irradiation to the prostate only (Group P), 154 patients (62%) received irradiation to the prostate and seminal vesicles (Group PSV), and 45 patients (18%) received modified pelvic fields (Group MPF). Androgen deprivation was given to 86% of patients. Median follow-up was 62 months. Late gastrointestinal (GI) and genitourinary (GU) morbidity were recorded according to the Radiation Therapy Oncology Group scoring system. Results: We observed 9%, 7%, and 25% Grade 2 or higher GI morbidity and 36%, 30%, and 21% Grade 2 or higher GU morbidity in Groups P, PSV, and MPF, respectively. In multivariate analyses, age and treatment group were independent predictors for the incidence of late Grade 2 or higher GI morbidity, whereas age and urinary symptoms before treatment were independent predictors for late Grade 2 or higher GU morbidity. Acute side effects predicted for late effects. The rectum dose-volume histogram parameters correlated with the incidence of late Grade 2 or higher GI morbidity, especially the fractional volume receiving more than 40-43 Gy. At 5 years of follow-up, the rate of Grade 2 late GI morbidity was only 1.4%, and Grade 2 or higher GU morbidity was 10.6%. Conclusions: The data presented here show that late GI morbidity after prostate RT is low and subsides with time.

  7. Dose-Rate Dependence of High-Dose Health Effects in Humans from Photon Radiation with Application to Radiological Terrorism

    SciTech Connect

    Strom, Daniel J.

    2005-01-14

    In 1981, as part of a symposium entitled ''The Control of Exposure of the Public to Ionizing Radiation in the Event of Accident or Attack,'' Lushbaugh, H?bner, and Fry published a paper examining ''radiation tolerance'' of various human health endpoints as a function of dose rate. This paper may not have received the notice it warrants. The health endpoints examined by Lushbaugh et al. were the lethal dose that will kill 50% of people within 60 days of exposure without medical care (LD50/60); severe bone marrow damage in healthy men; severe bone marrow damage in leukemia patients; temporary sterility (azoospermia); reduced male fertility; and late effects such as cancer. Their analysis was grounded in extensive clinical experience and anchored to a few selected data points, and based on the 1968 dose-rate dependence theory of J.L. Bateman. The Lushbaugh et al. paper did not give predictive equations for the relationships, although they were implied in the text, and the relationships were presented in a non-intuitive way. This work derives the parameters needed in Bateman's equation for each health endpoint, tabulates the results, and plots them in a more conventional manner on logarithmic scales. The results give a quantitative indication of how the human organism can tolerate more radiation dose when it is delivered at lower dose rates. For example, the LD50/60 increases from about 3 grays (300 rads) when given at very high dose rates to over 10 grays (1,000 rads) when given at much lower dose rates over periods of several months. The latter figure is borne out by the case of an individual who survived for at least 19 years after receiving doses in the range of 9 to 17 grays (900-1700 rads) over 106 days. The Lushbaugh et al. work shows the importance of sheltering when confronted with long-term exposure to radiological contamination such as would be expected from a radiological dispersion event, reactor accident, or ground-level nuclear explosion.

  8. Once Daily High-dose Radiation (≥60 Gy) Treatment in Limited Stage Small Cell Lung Cancer

    PubMed Central

    Zahra, Amir; Chang, Tangel; Hejleh, Taher Abu; Furqan, Muhammad; Clamon, Gerald H.; Bhatia, Sudershan K.; Watkins, John M.; Mott, Sarah L.; Ahmann, Logan L.; Bodeker, Kellie L.; Spitz, Douglas R.; Buatti, John M.; Allen, Bryan G.

    2016-01-01

    Background To investigate outcomes and prognostic factors in patients treated with once daily high-dose (≥60 Gy) radiation therapy (HDRT) and concurrent platinum-based chemotherapy in limited stage small cell lung cancer (LS-SCLC). While we await current phase III trials to determine optimal radiation dose fractionation schemes in LS-SCLC, we report our experience in LS-SCLC with once daily HDRT. We hypothesized that HDRT would achieve similar efficacy and tolerability as twice daily therapy. Methods We conducted a single institution retrospective review of all patients with LS-SCLC who underwent curative intent treatment from 2005–2013. Patients treated with HDRT (≥60 Gy) and concurrent chemotherapy (cisplatin or carboplatin and etoposide) were included in our analysis. Clinicopathologic variables assessed include gender, performance status, time to treatment, response to treatment, toxicity, volumetric tumor response at 3 months, and use of prophylactic cranial irradiation (PCI). Results 42 patients with LS-SCLC who initiated concurrent chemoradiation from 2005 to 2013 were included in the analysis. 38 patients (90%) completed definitive treatment to the lung; 16 (38%) also completed PCI. Median failure free survival (FFS) and overall survival (OS) were 11.9 and 23.1 months, respectively. Two-year and 5-year OS rates were 47% (CI=30–62%) and 21% (CI=7–38%), respectively. On univariate analysis, PCI was associated with improved FFS but this was not significant (p=0.18). Gender was the only co-variate significantly associated with statistical differences in FFS (p=0.03) and OS (p=0.02). Grade 3 and 4 esophagitis were 10.5% and 2.6%, respectively. Pre-HDRT tumor volume and 3-month post-treatment tumor volume were both associated with FFS (p<0.01) but not OS. Conclusions In this single institution series, daily HDRT demonstrated a 2-year OS of 47% in LS-SCLC. This compares well to the historical survival of daily fractionation (47%) from INT 0096 reported

  9. Lack of high-dose radiation mediated prostate cancer promotion and low-dose radiation adaptive response in the TRAMP mouse model.

    PubMed

    Lawrence, M D; Ormsby, R J; Blyth, B J; Bezak, E; England, G; Newman, M R; Tilley, W D; Sykes, P J

    2013-10-01

    Cancer of the prostate is a highly prevalent disease with a heterogeneous aetiology and prognosis. Current understanding of the biological mechanisms underlying the responses of prostate tissue to ionizing radiation exposure, including cancer induction, is surprisingly limited for both high- and low-dose exposures. As population exposure to radiation increases, largely through medical imaging, a better understanding of the response of the prostate to radiation exposure is required. Low-dose radiation-induced adaptive responses for increased cancer latency and decreased cancer frequency have been demonstrated in mouse models, largely for hematological cancers. This study examines the effects of high- and low-dose whole-body radiation exposure on prostate cancer development using an autochthonous mouse model of prostate cancer: TRansgenic Adenocarcinoma of the Mouse Prostate (TRAMP). TRAMP mice were exposed to single acute high (2 Gy), low (50 mGy) and repeated low (5 × 50 mGy) doses of X rays to evaluate both the potential prostate cancer promoting effects of high-dose radiation and low-dose adaptive response phenomena in this prostate cancer model. Prostate weights and histopathology were examined to evaluate gross changes in cancer development and, in mice exposed to a single 2 Gy dose, time to palpable tumor was examined. Proliferation (Ki-67), apoptosis, DNA damage (γ-H2AX) and transgene expression (large T-antigen) were examined within TRAMP prostate sections. Neither high- nor low-dose radiation-induced effects on prostate cancer progression were observed for any of the endpoints studied. Lack of observable effects of high- or low-dose radiation exposure suggests that modulation of tumorigenesis in the TRAMP model is largely resistant to such exposures. However, further study is required to better assess the effects of radiation exposure using alternative prostate cancer models that incorporate normal prostate and in those that are not driven by SV40 large T

  10. Three dimensional interactive display

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    2005-01-01

    A three-dimensional (3-D) interactive display and method of forming the same, includes a transparent capaciflector (TC) camera formed on a transparent shield layer on the screen surface. A first dielectric layer is formed on the shield layer. A first wire layer is formed on the first dielectric layer. A second dielectric layer is formed on the first wire layer. A second wire layer is formed on the second dielectric layer. Wires on the first wire layer and second wire layer are grouped into groups of parallel wires with a turnaround at one end of each group and a sensor pad at the opposite end. An operational amplifier is connected to each of the sensor pads and the shield pad biases the pads and receives a signal from connected sensor pads in response to intrusion of a probe. The signal is proportional to probe location with respect to the monitor screen.

  11. Prediction of radiation-induced liver disease by Lyman normal-tissue complication probability model in three-dimensional conformal radiation therapy for primary liver carcinoma

    SciTech Connect

    Xu ZhiYong; Liang Shixiong; Zhu Ji; Zhu Xiaodong; Zhao Jiandong; Lu Haijie; Yang Yunli; Chen Long; Wang Anyu; Fu Xiaolong; Jiang Guoliang . E-mail: jianggl@21cn.com

    2006-05-01

    Purpose: To describe the probability of RILD by application of the Lyman-Kutcher-Burman normal-tissue complication (NTCP) model for primary liver carcinoma (PLC) treated with hypofractionated three-dimensional conformal radiotherapy (3D-CRT). Methods and Materials: A total of 109 PLC patients treated by 3D-CRT were followed for RILD. Of these patients, 93 were in liver cirrhosis of Child-Pugh Grade A, and 16 were in Child-Pugh Grade B. The Michigan NTCP model was used to predict the probability of RILD, and then the modified Lyman NTCP model was generated for Child-Pugh A and Child-Pugh B patients by maximum-likelihood analysis. Results: Of all patients, 17 developed RILD in which 8 were of Child-Pugh Grade A, and 9 were of Child-Pugh Grade B. The prediction of RILD by the Michigan model was underestimated for PLC patients. The modified n, m, TD{sub 5} (1) were 1.1, 0.28, and 40.5 Gy and 0.7, 0.43, and 23 Gy for patients with Child-Pugh A and B, respectively, which yielded better estimations of RILD probability. The hepatic tolerable doses (TD{sub 5}) would be MDTNL of 21 Gy and 6 Gy, respectively, for Child-Pugh A and B patients. Conclusions: The Michigan model was probably not fit to predict RILD in PLC patients. A modified Lyman NTCP model for RILD was recommended.

  12. Three-Dimensional Complex Variables

    NASA Technical Reports Server (NTRS)

    Martin, E. Dale

    1988-01-01

    Report presents new theory of analytic functions of three-dimensional complex variables. While three-dimensional system subject to more limitations and more difficult to use than the two-dimensional system, useful in analysis of three-dimensional fluid flows, electrostatic potentials, and other phenomena involving harmonic functions.

  13. Evaluation of a three-dimensional MR acoustic radiation force imaging pulse sequence using a novel unbalanced bipolar motion encoding gradient.

    PubMed

    de Bever, Joshua T; Odéen, Henrik; Todd, Nick; Farrer, Alexis I; Parker, Dennis L

    2016-09-01

    MR guided focused ultrasound procedures require accurate focal spot localization in three dimensions. This study presents a three-dimensional (3D) pulse sequence for acoustic radiation force imaging (ARFI) that efficiently localizes the focal spot by means of ultrasound induced tissue displacement over a large field-of-view. A novel unbalanced bipolar motion encoding gradient was implemented to maximize time available for motion encoding, reduce echo times, and allow for longer echo train lengths. Two advanced features, kz reduction factor (KZRF) and kz -level interleaving, were implemented to reduce tissue heating. Studies in gelatin phantoms compared the location of peak displacement and temperature measured by 3D MR thermometry. MR-ARFI induced tissue heating was evaluated through a parametric study of sequence parameters and MR thermometry measurements during repeated application of ARFI sonication patterns. Sequence performance was characterized in the presence of respiration and tissue inhomogeneity. The location of peak displacement and temperature rise agreed within 0.2 ± 0.1 mm and 0.5 ± 0.3 mm in the transverse and longitudinal direction, respectively. The 3D displacement maps were acquired safely, and the KZRF and kz -level interleaving features reduced tissue heating by 51%. High quality displacement maps were obtained despite respiration and tissue inhomogeneities. This sequence provides a safe, accurate, and simple approach to localizing the focal spot in three dimensions with a single scan. Magn Reson Med 76:803-813, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  14. Patient outcomes of monotherapy with hypofractionated three-dimensional conformal radiation therapy for stage T2 or T3 non-small cell lung cancer: a retrospective study.

    PubMed

    Sakaguchi, Masakuni; Maebayashi, Toshiya; Aizawa, Takuya; Ishibashi, Naoya; Fukushima, Shoko; Abe, Osamu; Saito, Tsutomu

    2016-01-19

    Hypofractionated three-dimensional conformal radiation therapy (3D-CRT) is a treatment option for patients with early-stage non-small cell lung cancer (NSCLC) who are medically unable to tolerate surgery and who are not amenable to treatment with stereotactic body radiotherapy. This study assessed the efficacy and safety of 3D-CRT as a monotherapy in patients with localized stage T2 or T3 NSCLC. This retrospective study consisted of 29 patients (20 males) aged 56-89 years (median, 76 years) with histologically confirmed NSCLC who underwent 3D-CRT between 2005 and 2014. The median duration of patient observation was 17.0 months (range, 1.0-64.0 months). Complete and partial responses occurred in 13.8 and 44.8 % of patients, respectively, and the overall response rate was 58.2 %. Meanwhile, the 1- and 3-year survival rates were 65.8 and 33.8 %, respectively. In T2 NSCLC, the median survival time (MST) was 12 months, and the 1- and 3-year survival rates were 62.4 and 21.4 %, respectively. In T3 NSCLC, the MST was 17 months, and the 1- and 3-year survival rates were 72.9 and 48.6 %, respectively. Severe toxicities (Common Terminology Criteria Grade 3) were not observed. The mean biologically effective dose required to improve local control exceeded 80 Gy (range, 67.2-96.0 Gy). These findings support a role for 3D-CRT as a treatment option for patients who refuse or could not tolerate surgical therapy with early-stage NSCLC. Although this was a small, retrospective study, it may form the basis for future, larger controlled studies on 3D-CRT as a monotherapy for NSCLC.

  15. Synchrotron radiation micro-CT at the micrometer scale for the analysis of the three-dimensional morphology of microcracks in human trabecular bone.

    PubMed

    Larrue, Aymeric; Rattner, Aline; Peter, Zsolt-Andrei; Olivier, Cécile; Laroche, Norbert; Vico, Laurence; Peyrin, Françoise

    2011-01-01

    Bone quality is an important concept to explain bone fragility in addition to bone mass. Among bone quality factors, microdamage which appears in daily life is thought to have a marked impact on bone strength and plays a major role in the repair process. The starting point for all studies designed to further our understanding of how bone microdamage initiate or dissipate energy, or to investigate the impact of age, gender or disease, remains reliable observation and measurement of microdamage. In this study, 3D Synchrotron Radiation (SR) micro-CT at the micrometric scale was coupled to image analysis for the three-dimensional characterization of bone microdamage in human trabecular bone specimens taken from femoral heads. Specimens were imaged by 3D SR micro-CT with a voxel size of 1.4 µm. A new tailored 3D image analysis technique was developed to segment and quantify microcracks. Microcracks from human trabecular bone were observed in different tomographic sections as well as from 3D renderings. New 3D quantitative measurements on the microcrack density and morphology are reported on five specimens. The 3D microcrack density was found between 3.1 and 9.4/mm3 corresponding to a 2D density between 0.55 and 0.76 /mm2. The microcrack length and width measured in 3D on five selected microcrack ranged respectively from 164 µm to 209 µm and 100 µm to 120 µm. This is the first time that various microcracks in unloaded human trabecular bone--from the simplest linear crack to more complex cross-hatch cracks--have been examined and quantified by 3D imaging at this scale. The suspected complex morphology of microcracks is here considerably more evident than in the 2D observations. In conclusion, this technique opens new perspective for the 3D investigation of microcracks and the impact of age, disease or treatment.

  16. Four-Year Efficacy, Cosmesis, and Toxicity Using Three-Dimensional Conformal External Beam Radiation Therapy to Deliver Accelerated Partial Breast Irradiation

    SciTech Connect

    Chen, Peter Y.; Wallace, Michelle; Mitchell, Christina; Grills, Inga; Kestin, Larry; Fowler, Ashley; Martinez, Alvaro; Vicini, Frank

    2010-03-15

    Purpose: This prospective study examines the use of three-dimensional conformal external beam radiation therapy (3D-CRT) to deliver accelerated partial breast irradiation (APBI). Four-year data on efficacy, cosmesis, and toxicity are presented. Methods: Patients with Stage O, I, or II breast cancer with lesions <=3 cm, negative margins, and negative nodes were eligible. The 3D-CRT delivered was 38.5 Gy in 3.85 Gy/fraction. Ipsilateral breast, ipsilateral nodal, contralateral breast, and distant failure (IBF, INF, CBF, DF) were estimated using the cumulative incidence method. Disease-free, overall, and cancer-specific survival (DFS, OS, CSS) were recorded. The National Cancer Institute Common Terminology Criteria for Adverse Events (version 3) toxicity scale was used to grade acute and late toxicities. Results: Ninety-four patients are evaluable for efficacy. Median patient age was 62 years with the following characteristics: 68% tumor size <1 cm, 72% invasive ductal histology, 77% estrogen receptor (ER) (+), 88% postmenopausal; 88% no chemotherapy and 44% with no hormone therapy. Median follow-up was 4.2 years (range, 1.3-8.3). Four-year estimates of efficacy were IBF: 1.1% (one local recurrence); INF: 0%; CBF: 1.1%; DF: 3.9%; DFS: 95%; OS: 97%; and CSS: 99%. Four (4%) Grade 3 toxicities (one transient breast pain and three fibrosis) were observed. Cosmesis was rated good/excellent in 89% of patients at 4 years. Conclusions: Four-year efficacy, cosmesis, and toxicity using 3D-CRT to deliver APBI appear comparable to other experiences with similar follow-up. However, additional patients, further follow-up, and mature Phase III data are needed to evaluate thoroughly the extent of application, limitations, and complete value of this particular form of APBI.

  17. Late radiation side effects, cosmetic outcomes and pain in breast cancer patients after breast-conserving surgery and three-dimensional conformal radiotherapy : Risk-modifying factors.

    PubMed

    Hille-Betz, Ursula; Vaske, Bernhard; Bremer, Michael; Soergel, Philipp; Kundu, Sudip; Klapdor, Rüdiger; Hillemanns, Peter; Henkenberens, Christoph

    2016-01-01

    The purpose of this work was to identify parameters influencing the risk of late radiation side effects, fair or poor cosmetic outcomes (COs) and pain in breast cancer patients after breast-conserving therapy (BCT) and three-dimensional conformal radiotherapy (3D-CRT). Between 2006 and 2013, 159 patients were treated at the Hannover Medical School. Physician-rated toxicity according to the LENT-SOMA criteria, CO and pain were assessed by multivariate analysis. LENT-SOMA grade 1-4 toxicity was observed as follows: fibrosis 10.7 %, telangiectasia 1.2 %, arm oedema 8.8 % and breast oedema 5.0 %. In addition, 15.1 % of patients reported moderate or severe breast pain, and 21.4 % complained about moderate or severe pain in the arm or shoulder. In multivariate analysis, axillary clearing (AC) was significantly associated with lymphoedema of the arm [odds ratio (OR) 4.37, p = 0.011, 95 % confidence interval (CI) 1.4-13.58]. Breast oedema was also highly associated with AC (OR 10.59, p = 0.004, 95 % CI 2.1-53.36), a ptosis grade 2/3 or pseudoptosis and a bra size ≥ cup C (OR 5.34, p = 0.029, 95 % CI 1.2-24.12). A ptosis grade 2/3 or pseudoptosis and a bra size ≥ cup C were the parameters significantly associated with an unfavourable CO (OR 3.19, p = 0.019, 95 % CI 1.2-8.4). Concerning chronic breast pain, we found a trend related to the prescribed radiation dose including boost (OR 1.077, p = 0.060, 95 % CI 0.997-1.164). Chronic shoulder or arm pain was statistically significantly associated with lymphoedema of the arm (OR 3.9, p = 0.027, 95 % CI 1.17-13.5). Chronic arm and breast oedema were significantly influenced by the extent of surgery (AC). Ptotic and large breasts were significantly associated with unfavourable COs and chronic breast oedema. Late toxicities exclusive breast pain were not associated with radiotherapy parameters.

  18. Three-dimensional diffusion of non-sorbing species in porous sandstone: computer simulation based on X-ray microtomography using synchrotron radiation.

    PubMed

    Nakashima, Yoshito; Nakano, Tsukasa; Nakamura, Koichi; Uesugi, Kentaro; Tsuchiyama, Akira; Ikeda, Susumu

    2004-10-01

    The diffusion pathways of porous sandstone were examined by a three-dimensional (3-D) imaging technique based on X-ray computed tomography (CT) using the SPring-8 (Super Photon ring-8 GeV, Hyogo, Japan) synchrotron radiation facility. The analysis was undertaken to develop better understanding of the diffusion pathways in natural rock as a key factor in clarifying the detailed mechanism of the diffusion of radionuclides and water molecules through the pore spaces of natural barriers in underground nuclear waste disposal facilities. A cylindrical sample (diameter 4 mm, length 6 mm) of sandstone (porosity 0.14) was imaged to obtain a 3-D image set of 450(3) voxels=2.62(3) mm(3). Through cluster-labeling analysis of the 3-D image set, it was revealed that 89% of the pore space forms a single large pore-cluster responsible for macroscopic diffusive transport, while only 11% of the pore space is made up of isolated pores that are not involved in long-range diffusive transport. Computer simulations of the 3-D diffusion of non-sorbing random walkers in the largest pore cluster were performed to calculate the surface-to-volume ratio of the pore, tortuosity (diffusion coefficient in free space divided by that in porous rock). The results showed that (i) the simulated surface-to-volume ratio is about 60% of the results obtained by conventional pulsed-field-gradient proton nuclear magnetic resonance (NMR) laboratory experiments and (ii) the simulated tortuosity is five to seven times larger than the results of laboratory diffusion experiments using non-sorbing I(-) and Br(-). These discrepancies are probably attributed to the intrinsic sample heterogeneity and limited spatial resolution of the CT system. The permeability was also estimated based on the NMR diffusometry theory using the results of the random walk simulations via the Kozeny-Carman equation. The estimated permeability involved an error of about 20% compared with the permeability measured by the conventional

  19. Phase I Three-Dimensional Conformal Radiation Dose Escalation Study in Newly Diagnosed Glioblastoma: Radiation Therapy Oncology Group Trial 98-03

    SciTech Connect

    Tsien, Christina Moughan, Jennifer; Michalski, Jeff M.; Gilbert, Mark R.; Purdy, James; Simpson, Joseph; Kresel, John J.; Curran, Walter J.; Diaz, Aidnag; Mehta, Minesh P.

    2009-03-01

    Purpose: To evaluate in a Phase I trial the feasibility and toxicity of dose-escalated three-dimensional conformal radiotherapy (3D-CRT) concurrent with chemotherapy in patients with primary supratentorial glioblastoma (GBM). Methods and Materials: A total of 209 patients were enrolled. All received 46 Gy in 2-Gy fractions to the first planning target volume (PTV{sub 1}), defined as the gross tumor volume (GTV) plus 1.8 cm. A subsequent boost was given to PTV{sub 2}, defined as GTV plus 0.3 cm. Patients were stratified into two groups (Group 1: PTV{sub 2} <75 cm{sup 3}; Group 2: PTV{sub 2} {>=}75 cm{sup 3}). Four RT dose levels were evaluated: 66, 72, 78, and 84 Gy. Carmustine 80 mg/m{sup 2} was given during RT, then every 8 weeks for 6 cycles. Pretreatment characteristics were well balanced. Results: Acute and late Grade 3/4 RT-related toxicities were no more frequent at higher RT dose or with larger tumors. There were no dose-limiting toxicities (acute Grade {>=}3 irreversible central nervous system toxicities) observed on any dose level in either group. On the basis of the absence of dose-limiting toxicities, dose was escalated to 84 Gy in both groups. Late RT necrosis was noted at 66 Gy (1 patient), 72 Gy (2 patients), 78 Gy (2 patients), and 84 Gy (3 patients) in Group 1. In Group 2, late RT necrosis was noted at 78 Gy (1 patient) and 84 Gy (2 patients). Median time to RT necrosis was 8.8 months (range, 5.1-12.5 months). Median survival in Group 1 was 11.6-19.3 months. Median survival in Group 2 was 8.2-13.9 months. Conclusions: Our study shows the feasibility of delivering higher than standard (60 Gy) RT dose with concurrent chemotherapy for primary GBM, with an acceptable risk of late central nervous system toxicity.

  20. Image guided radiation therapy boost in combination with high-dose-rate intracavitary brachytherapy for the treatment of cervical cancer

    PubMed Central

    Wang, Xianliang; Li, Jie; Yuan, Ke; Yin, Gang; Wan, Bin

    2016-01-01

    Purpose The purpose of this study was to demonstrate the dosimetric and clinical feasibility of image guided radiation therapy (IGRT) combined with high-dose-rate (HDR) intracavitary brachytherapy (ICBT) to improve dose distribution in cervical cancer treatment. Material and methods For 42 cervical cancer patients, magnetic resonance imaging (MRI) scans were acquired after completion of whole pelvic irradiation 45-46 Gy and 5 fractions of B + I (ICBT + IGRT) treatment were subsequently received. The high risk clinical target volume (HRCTV), intermediate risk clinical target volume (IRCTV), bladder, rectum, and sigmoid were contoured on the computed tomography (CT) scans. The total planning aim doses for HRCTV was D90% > 85 Gy, whilst constraints for rectum and sigmoid were D2cc < 75 Gy and D2cc < 90 Gy for bladder in terms of an equivalent dose in 2 Gy (EQD2) for external beam radiotherapy (EBRT) and brachytherapy boost. The IGRT plan was optimized on top of the ICBT dose distribution. A dosimetric comparison was made between B + I and optimized ICBT (O-ICBT) only. Results The mean D90% of HRCTV was comparable for B + I and O-ICBT (p = 0.82). For B + I plan, HRCTV D100%, IRCTV D100%, and IRCTV D90% were significantly increased by a mean of 10.52 Gy, 5.61 Gy, and 2.70 Gy, respectively (p < 0.01). The D2cc for bladder, rectum, and sigmoid were lower by a mean of 21.36, 6.78, and 10.65 Gy, respectively (p < 0.01). The mean rectum V60 Gy value over 42 patients was almost the same for both techniques but for bladder and sigmoid B + I had higher V60 Gy mean values as compared with the O-ICBT. Conclusions B + I can improve dose distribution in cervical cancer treatment; it could be useful for tumors extended beyond the reach of intracavitary/interstitial brachytherapy (IC/ISBT) or for centers that are inexperienced or ill-equipped with IC/ISBT techniques. Additional confirmatory prospective studies with larger numbers of patients and longer follow-up are required to

  1. The Value of Botox-A in Acute Radiation Proctitis: Results From a Phase I/II Study Using a Three-Dimensional Scoring System

    SciTech Connect

    Vuong, Te; Waschke, Kevin; Niazi, Tamim; Richard, Carole; Parent, Josee; Liberman, Sender; Mayrand, Serge; Loungnarath, Rasmy; Stein, Barry; Devic, Slobodan

    2011-08-01

    Purpose: Acute radiation proctitis (ARP) is a common side effect of pelvic radiotherapy, and its management is challenging in daily practice. The present phase I/II study evaluates the safety and efficacy of the botulinum toxin A (BTX-A) in ARP treatment for rectal cancer patients undergoing neoadjuvant high-dose-rate endorectal brachytherapy (HDREBT). Methods and Materials: Fifteen patients, treated with neoadjuvant HDREBT, 26-Gy in 4 fractions, received the study treatment that consisted of a single injection of BTX-A into the rectal wall. The injection was performed post-HDREBT and prior to the development of ARP. The control group, 20 such patients, did not receive the BTX-A injection. Both groups had access to standard treatment with hydrocortisone rectal aerosol foam (Cortifoam) and anti-inflammatory and narcotic medication. The ARP was clinically evaluated by self-administered daily questionnaires using visual analog scores to document frequency and urgency of bowel movements, rectal burning/tenesmus, and pain symptoms before and after HDREBT. Results: At the time of this analysis, there was no observed systemic toxicity. Patient compliance with the self-administered questionnaire was 100% from week 1 to 4, 70% during week 5, and 40% during week 6. The maximum tolerated dose was established at the 100-U dose level, and noticeable mean differences were observed in bowel frequency (p = 0.016), urgency (p = 0.007), and pain (p = 0.078). Conclusions: This study confirms the feasibility and efficacy of BTX-A intervention at 100-U dose level for study patients compared to control patients. A phase III study with this dose level is planned to validate these results.

  2. Three-dimensional Monte Carlo dust radiative transfer study of the H-poor planetary nebula IRAS 18333-2357 located in M22

    NASA Astrophysics Data System (ADS)

    Muthumariappan, C.

    2017-09-01

    We analyse the characteristics of dust and its distribution in the planetary nebula IRAS 18333-2357 located in M22 using a three-dimensional radiative transfer code Hochunk3D. The spectral energy distribution was constructed using ultraviolet, optical and infrared archival data. We also have used Spitzer 8-μm and Wide-field Infrared Survey Explorer (WISE) 22-μm images for our study. Taking into account that the dust shell is carbon-rich, models are presented for amorphous carbon and graphite grains. The spectral energy distribution and the thermal images are fit better by the amorphous carbon model than the graphite model. The stellar photospheric temperature is (50 000 ± 3000) K. IRAS 18333-2357 has a (40 ± 2)° inclined equatorial disc and a thin spherical shell around it, similar to the inner geometry of the born-again planetary nebula A30. Disc inner and outer radii are (2.8 ± 0.1) and (6.0 ± 0.6) arcsec, respectively. The inner and outer radii of the shell are (13.3 ± 1.5) and (25 ± 4) arcsec, respectively. Incorporating a very small grain population, we explain the excess emission in the region of 3-12 μm. The stellar bolometric luminosity is (2460 ± 800) L⊙ and the luminosity reprocessed by dust is (630 ± 200) L⊙. The masses of very small grain population and the classical dust grains are (9.4 ± 0.75) × 10-4 M⊙ and (3.1 ± 0.24) × 10-3 M⊙, respectively, resulting in a total dust mass of (4.1 ± 0.31)× 10-3 M⊙. The derived gas-to-dust mass ratio is 7 ± 1. We discuss a possible origin of IRAS 18333-2357 from a born-again event. The faint envelope seen in the WISE 22-μm image may contain H-rich matter ejected before the H-deficient nebula.

  3. Three dimensional Dirac semimetals

    NASA Astrophysics Data System (ADS)

    Zaheer, Saad

    We extend the physics of graphene to three dimensional systems by showing that Dirac points can exist on the Fermi surface of realistic materials in three dimensions. Many of the exotic electronic properties of graphene can be ascribed to the pseudorelativistic behavior of its charge carriers due to two dimensional Dirac points on the Fermi surface. We show that certain nonsymmorphic spacegroups exhibit Dirac points among the irreducible representations of the appropriate little group at high symmetry points on the surface of the Brillouin zone. We provide a list of all Brillouin zone momenta in the 230 spacegroups that can host Dirac points. We describe microscopic considerations necessary to design materials in one of the candidate spacegroups such that the Dirac point appears at the Fermi energy without any additional non-Dirac-like Fermi pockets. We use density functional theory based methods to propose six new Dirac semimetals: BiO 2 and SbO2 in the beta-cristobalite lattice (spacegroup 227), and BiCaSiO4, BiMgSiO4, BiAlInO 4, and BiZnSiO4 in the distorted spinels lattice (spacegroup 74). Additionally we derive effective Dirac Hamiltonians given group representative operators as well as tight binding models incorporating spin-orbit coupling. Finally we study the Fermi surface of zincblende (spacegroup 216) HgTe which is effectively point-like at Gamma in the Brillouin zone and exhibits accidental degeneracies along a threefold rotation axis. Whereas compressive strain gaps the band structure into a topological insulator, tensile strain shifts the accidental degeneracies away from Gamma and enlarges the Fermi surface. States on the Fermi surface exhibit nontrivial spin texture marked by winding of spins around the threefold rotation axis and by spin vortices indicating a change in the winding number. This is confirmed by microscopic calculations performed in tensile strained HgTe and Hg0.5Zn 0.5 Te as well as k.p theory. We conclude with a summary of recent

  4. Dose optimization of fractionated external radiation and high-dose-rate intracavitary brachytherapy for FIGO stage IB uterine cervical carcinoma.

    PubMed

    Lee, Sang-wook; Suh, Chang Ok; Chung, Eun Ji; Kim, Gwi Eon

    2002-04-01

    To determine the optimal dose combination scheme of external beam radiotherapy (EBRT) and high-dose-rate (HDR) intracavitary radiation (ICR) for maximizing tumor control while conferring an acceptable late complication rate in the treatment of Stage IB uterine cervical cancer. We retrospectively analyzed 162 patients with International Federation of Gynecology and Obstetrics (FIGO) Stage IB squamous cell carcinoma of the uterine cervix who received definitive RT between May 1979 and December 1990. Before HDR-ICR, all patients received EBRT to a total dose of 40-46 Gy (median 45), administered during 4-5 weeks to the whole pelvis. HDR-ICR was given 3 times weeks to a total dose of 24-51 Gy (median 39) at point A, using a dose of 3 Gy/fraction. Central shielding from EBRT was begun after the delivery using 20-45 Gy (median 40) of the external dose. The total dose to point A, calculated by adding the EBRT biologically effective dose (BED) and the ICR BED to point A, was 74.1-118.1 Gy (mean 95.2). The rectal point dose was calculated at the anterior rectal wall at the level of the cervical os. The local control rate, survival rate, and late complication rate were analyzed according to the irradiation dose and BED. The initial complete response rate was 99.4%. The overall 5-year survival rate and 5-year disease-free survival rate was 91.1% and 90.9%, respectively. The local failure rate was 4.9%, and the distant failure rate was 4.3%. Late complications were mild and occurred in 23.5% of patients, with 18.5% presenting with rectal complications and 4.9% with bladder complications. The mean rectal BED (the sum of the external midline BED and the ICR rectal point BED) was lower in the patients without rectal complications than in those with rectal complications (125.6 Gy vs. 142.7 Gy, p = 0.3210). The late rectal complication rate increased when the sum of the external midline BED and the rectal BED by ICR was >or=131 Gy (p = 0.1962). However, 5-year survival rates did

  5. Radiation-induced lung fibrosis after treatment of small cell carcinoma of the lung with very high-dose cyclophosphamide

    SciTech Connect

    Trask, C.W.; Joannides, T.; Harper, P.G.; Tobias, J.S.; Spiro, S.G.; Geddes, D.M.; Souhami, R.L.; Beverly, P.C.

    1985-01-01

    Twenty-five previously untreated patients with small cell carcinoma of the lung were treated with cyclophosphamide 160 to 200 mg/kg (with autologous bone marrow support) followed by radiotherapy (4000 cGy) to the primary site and mediastinum. No other treatment was given until relapse occurred. Nineteen patients were assessable at least 4 months after radiotherapy; of these, 15 (79%) developed radiologic evidence of fibrosis, which was symptomatic in 14 (74%). The time of onset of fibrosis was related to the volume of lung irradiated. A retrospective analysis was made of 20 consecutive patients treated with multiple-drug chemotherapy and an identical radiotherapy regimen as part of a randomized trial. Radiologic and symptomatic fibrosis was one half as frequent (35%) as in the high-dose cyclophosphamide group. Very high-dose cyclophosphamide appears to sensitize the lung to radiotherapy and promotes the production of fibrosis.

  6. Three-dimensional simulations of the generation of one Angstrom radiation by a self-amplified spontaneous emission free-electron laser

    SciTech Connect

    Goldstein, J.C.; Elliott, C.J.; Schmitt, M.J.

    1990-01-01

    Three-dimensional numerical simulations of the generation of one Angstrom x-rays by a free-electron laser operating in the self-amplified spontaneous emission mode have been performed. Using model electron beam and wiggler parameters, we have investigated the length of wiggler needed to just avoid bandwidth broadening effects associated with gain saturation, and we have also obtained requirements for wiggler field errors to avoid significant loss of performance. 14 refs., 5 figs., 1 tab.

  7. Three-dimensional ultrasound scanning.

    PubMed

    Fenster, Aaron; Parraga, Grace; Bax, Jeff

    2011-08-06

    The past two decades have witnessed developments of new imaging techniques that provide three-dimensional images about the interior of the human body in a manner never before available. Ultrasound (US) imaging is an important cost-effective technique used routinely in the management of a number of diseases. However, two-dimensional viewing of three-dimensional anatomy, using conventional two-dimensional US, limits our ability to quantify and visualize the anatomy and guide therapy, because multiple two-dimensional images must be integrated mentally. This practice is inefficient, and may lead to variability and incorrect diagnoses. Investigators and companies have addressed these limitations by developing three-dimensional US techniques. Thus, in this paper, we review the various techniques that are in current use in three-dimensional US imaging systems, with a particular emphasis placed on the geometric accuracy of the generation of three-dimensional images. The principles involved in three-dimensional US imaging are then illustrated with a diagnostic and an interventional application: (i) three-dimensional carotid US imaging for quantification and monitoring of carotid atherosclerosis and (ii) three-dimensional US-guided prostate biopsy.

  8. Three-dimensional echocardiographic technology.

    PubMed

    Salgo, Ivan S

    2007-05-01

    This article addresses the current state of the art of technology in three-dimensional echocardiography as it applies to transducer design, beam forming, display, and quantification. Because three-dimensional echocardiography encompasses many technical and clinical areas, this article reviews its strengths and limitations and concludes with an analysis of what to use when.

  9. Three-Dimensional Photo Structures

    ERIC Educational Resources Information Center

    Vieth, Ken

    2006-01-01

    People influence lives in many ways. Through the author's desire to encourage high school students to reflect on the influential people in their lives, he developed this three-dimensional project in which they create a celebratory three-dimensional structure that shares their impressions of themselves and those who have influenced them. This…

  10. Three-dimensional ultrasound scanning

    PubMed Central

    Fenster, Aaron; Parraga, Grace; Bax, Jeff

    2011-01-01

    The past two decades have witnessed developments of new imaging techniques that provide three-dimensional images about the interior of the human body in a manner never before available. Ultrasound (US) imaging is an important cost-effective technique used routinely in the management of a number of diseases. However, two-dimensional viewing of three-dimensional anatomy, using conventional two-dimensional US, limits our ability to quantify and visualize the anatomy and guide therapy, because multiple two-dimensional images must be integrated mentally. This practice is inefficient, and may lead to variability and incorrect diagnoses. Investigators and companies have addressed these limitations by developing three-dimensional US techniques. Thus, in this paper, we review the various techniques that are in current use in three-dimensional US imaging systems, with a particular emphasis placed on the geometric accuracy of the generation of three-dimensional images. The principles involved in three-dimensional US imaging are then illustrated with a diagnostic and an interventional application: (i) three-dimensional carotid US imaging for quantification and monitoring of carotid atherosclerosis and (ii) three-dimensional US-guided prostate biopsy. PMID:22866228

  11. Patterns of Recurrence Analysis in Newly Diagnosed Glioblastoma Multiforme After Three-Dimensional Conformal Radiation Therapy With Respect to Pre-Radiation Therapy Magnetic Resonance Spectroscopic Findings

    SciTech Connect

    Park, Ilwoo; Chuang, Cynthia F.; Chang, Susan M.; Berger, Mitchel S.; Nelson, Sarah J.

    2007-10-01

    Purpose: To determine whether the combined magnetic resonance imaging (MRI) and magnetic resonance spectroscopy imaging (MRSI) before radiation therapy (RT) is valuable for RT target definition, and to evaluate the feasibility of replacing the current definition of uniform margins by custom-shaped margins based on the information from MRI and MRSI. Methods and Materials: A total of 23 glioblastoma multiforme (GBM) patients underwent MRI and MRSI within 4 weeks after surgery but before the initiation of RT and at 2-month follow-up intervals thereafter. The MRSI data were quantified on the basis of a Choline-to-NAA Index (CNI) as a measure of spectroscopic abnormality. A combined anatomic and metabolic region of interest (MRI/S) consisting of T2-weighted hyperintensity, contrast enhancement (CE), resection cavity, and CNI2 (CNI {>=} 2) based on the pre-RT imaging was compared to the extent of CNI2 and the RT dose distribution. The spatial relationship of the pre-RT MRI/S and the RT dose volume was compared with the extent of CE at each follow-up. Results: Nine patients showed new or increased CE during follow-up, and 14 patients were either stable or had decreased CE. New or increased areas of CE occurred within CNI2 that was covered by 60 Gy in 6 patients and within the CNI2 that was not entirely covered by 60 Gy in 3 patients. New or increased CE resided within the pre-RT MRI/S lesion in 89% (8/9) of the patients with new or increased CE. Conclusion: These data indicate that the definition of RT target volumes according to the combined morphologic and metabolic abnormality may be sufficient for RT targeting.

  12. INTERACTION OF LASER RADIATION WITH MATTER. LASER PLASMA: Initial stage of the development of three-dimensional periodic structures in laser melting

    NASA Astrophysics Data System (ADS)

    Dolgaev, Sergei I.; Kirichenko, N. A.; Simakin, Aleksandr V.; Shafeev, Georgii A.

    2004-08-01

    The initial stage of three-dimensional periodic structures developing during the laser melting of solids is numerically simulated. The temperature nonuniformity caused by reflectivity variations along a capillary wave leads to a self-consistent melt displacement under the action of the temperature gradient due to the temperature dependence of the surface tension coefficient. Based on the numerical solution of the simplified Navier—Stokes equation, the transformation of the initial sinusoidal perturbation of the melt surface is investigated at the stages of self-consistent laser heating and the subsequent cooling. The derived surface shape well agrees with experimental data.

  13. American Society for Radiation Oncology (ASTRO) and American College of Radiology (ACR) Practice Guideline for the Performance of High-Dose-Rate Brachytherapy

    SciTech Connect

    Erickson, Beth A.; Demanes, D. Jeffrey; Ibbott, Geoffrey S.; Hayes, John K.; Hsu, I-Chow J.; Morris, David E.; Rabinovitch, Rachel A.; Tward, Jonathan D.; Rosenthal, Seth A.

    2011-03-01

    High-Dose-Rate (HDR) brachytherapy is a safe and efficacious treatment option for patients with a variety of different malignancies. Careful adherence to established standards has been shown to improve the likelihood of procedural success and reduce the incidence of treatment-related morbidity. A collaborative effort of the American College of Radiology (ACR) and American Society for Therapeutic Radiation Oncology (ASTRO) has produced a practice guideline for HDR brachytherapy. The guideline defines the qualifications and responsibilities of all the involved personnel, including the radiation oncologist, physicist and dosimetrists. Review of the leading indications for HDR brachytherapy in the management of gynecologic, thoracic, gastrointestinal, breast, urologic, head and neck, and soft tissue tumors is presented. Logistics with respect to the brachytherapy implant procedures and attention to radiation safety procedures and documentation are presented. Adherence to these practice guidelines can be part of ensuring quality and safety in a successful HDR brachytherapy program.

  14. Brachial Plexus-Associated Neuropathy After High-Dose Radiation Therapy for Head-and-Neck Cancer

    SciTech Connect

    Chen, Allen M.; Hall, William H.; Li, Judy; Beckett, Laurel; Farwell, D. Gregory; Lau, Derick H.; Purdy, James A.

    2012-09-01

    Purpose: To identify clinical and treatment-related predictors of brachial plexus-associated neuropathies after radiation therapy for head-and-neck cancer. Methods and Materials: Three hundred thirty patients who had previously completed radiation therapy for head-and-neck cancer were prospectively screened using a standardized instrument for symptoms of neuropathy thought to be related to brachial plexus injury. All patients were disease-free at the time of screening. The median time from completion of radiation therapy was 56 months (range, 6-135 months). One-hundred fifty-five patients (47%) were treated by definitive radiation therapy, and 175 (53%) were treated postoperatively. Radiation doses ranged from 50 to 74 Gy (median, 66 Gy). Intensity-modulated radiation therapy was used in 62% of cases, and 133 patients (40%) received concurrent chemotherapy. Results: Forty patients (12%) reported neuropathic symptoms, with the most common being ipsilateral pain (50%), numbness/tingling (40%), motor weakness, and/or muscle atrophy (25%). When patients with <5 years of follow-up were excluded, the rate of positive symptoms increased to 22%. On univariate analysis, the following factors were significantly associated with brachial plexus symptoms: prior neck dissection (p = 0.01), concurrent chemotherapy (p = 0.01), and radiation maximum dose (p < 0.001). Cox regression analysis confirmed that both neck dissection (p < 0.001) and radiation maximum dose (p < 0.001) were independently predictive of symptoms. Conclusion: The incidence of brachial plexus-associated neuropathies after radiation therapy for head-and-neck cancer may be underreported. In view of the dose-response relationship identified, limiting radiation dose to the brachial plexus should be considered when possible.

  15. Assessment and Comparison of Homogeneity and Conformity Indexes in Step-and-Shoot and Compensator-Based Intensity Modulated Radiation Therapy (IMRT) and Three-Dimensional Conformal Radiation Therapy (3D CRT) in Prostate Cancer

    PubMed Central

    Salimi, Marzieh; Abi, Kaveh Shirani Tak; Nedaie, Hassan Ali; Hassani, Hossein; Gharaati, Hussain; Samei, Mahmood; Shahi, Rezgar; Zarei, Hamed

    2017-01-01

    Intensity modulated radiation therapy (IMRT) and three-dimensional conformal radiation therapy (3D CRT) are two treatment modalities in prostate cancer, which provide acceptable dose distribution in tumor region with sparing the surrounding normal tissues. IMRT is based on inverse planning optimization; in which, intensity of beams is modified by using multileaf collimators and also compensators with optimum shapes in step and shoot (SAS) and compensator-based method, respectively. In the recent study, some important parameters were compared in two IMRT and 3D CRT methods. Prescribed dose was 80 Gy for both IMRT procedures and 70 Gy for 3D CRT. Treatment plans of 15 prostate cancer candidates were compared to target the minimum dose, maximum dose, V 76 Gy (for IMRT plans) V 66.5 Gy (for 3D CRT), mean dose, conformity index (CI), and homogeneity index (HI). Dose conformity in compensators-based IMRT was better than SAS and 3D CRT. The same outcome was also achieved for homogeneity index. The target coverage was achieved 95% of prescribed dose to 95% of planning target volume (PTV) in 3D CRT and 95% of prescribed dose to 98% of PTV in IMRT methods. IMRT increases maximum dose of tumor region, improves CI and HI of target volume, and also reduces dose of organs at risks. PMID:28553583

  16. Concomitant 5-fluorouracil infusion and high-dose radiation for stage III non-small cell lung cancer

    SciTech Connect

    Lokich, J.; Chaffey, J.; Neptune, W. )

    1989-09-01

    Thirty patients with Stage III non-small cell lung cancer were entered on a trial to evaluate the feasibility of combined radiation and concomitant 5-fluorouracil infusion. Patients had received prior debulking surgery (nine), induction chemotherapy (16), or no therapy (five). Radiation employed standard fractionation (180-200 rad/day) administered to a median cumulative dose of 5500 rad (range, 4500-6200 rad). 5-Fluorouracil was infused 24 hours per day throughout the period of radiation at a dose of 300 mg/m2/day for a median of 42 days (range, 28-56 days). Radiation complications included pneumonitis three of 30 (10%) and esophagitis (27%). Chemotherapy complications included stomatitis, two of 27 (7%), and hand-foot syndrome, three of 30 (10%). Treatment interruptions were necessary in six of 30 (20%) and four of 30 required parenteral nutrition. At a median follow-up of 12 months 26/30 (87%) maintained local control and eight had distant metastases (three of whom presented with Stage IV disease). 5-Fluorouracil delivered continuously throughout standard fractionation radiation to high cumulative doses is feasible and practical. Comparative clinical trials of the various combined radiation and chemotherapy schedules employed are in order. One additional clinical observation was the identification of six of 30 (20%) with brain metastases at presentation or after 12 months, all of whom had adenocarcinoma histologic subtype.

  17. A Treatment Planning Method for Sequentially Combining Radiopharmaceutical Therapy and External Radiation Therapy;External beam therapy; Radiopharmaceutical therapy; Three-dimensional dosimetry; Treatment planning

    SciTech Connect

    Hobbs, Robert F.; McNutt, Todd; Baechler, Sebastien; He Bin; Esaias, Caroline E.; Frey, Eric C.; Loeb, David M.; Wahl, Richard L.; Shokek, Ori; Sgouros, George

    2011-07-15

    Purpose: Effective cancer treatment generally requires combination therapy. The combination of external beam therapy (XRT) with radiopharmaceutical therapy (RPT) requires accurate three-dimensional dose calculations to avoid toxicity and evaluate efficacy. We have developed and tested a treatment planning method, using the patient-specific three-dimensional dosimetry package 3D-RD, for sequentially combined RPT/XRT therapy designed to limit toxicity to organs at risk. Methods and Materials: The biologic effective dose (BED) was used to translate voxelized RPT absorbed dose (D{sub RPT}) values into a normalized total dose (or equivalent 2-Gy-fraction XRT absorbed dose), NTD{sub RPT} map. The BED was calculated numerically using an algorithmic approach, which enabled a more accurate calculation of BED and NTD{sub RPT}. A treatment plan from the combined Samarium-153 and external beam was designed that would deliver a tumoricidal dose while delivering no more than 50 Gy of NTD{sub sum} to the spinal cord of a patient with a paraspinal tumor. Results: The average voxel NTD{sub RPT} to tumor from RPT was 22.6 Gy (range, 1-85 Gy); the maximum spinal cord voxel NTD{sub RPT} from RPT was 6.8 Gy. The combined therapy NTD{sub sum} to tumor was 71.5 Gy (range, 40-135 Gy) for a maximum voxel spinal cord NTD{sub sum} equal to the maximum tolerated dose of 50 Gy. Conclusions: A method that enables real-time treatment planning of combined RPT-XRT has been developed. By implementing a more generalized conversion between the dose values from the two modalities and an activity-based treatment of partial volume effects, the reliability of combination therapy treatment planning has been expanded.

  18. Phase 2 Trial of Hypofractionated High-Dose Intensity Modulated Radiation Therapy With Concurrent and Adjuvant Temozolomide for Newly Diagnosed Glioblastoma

    SciTech Connect

    Iuchi, Toshihiko; Hatano, Kazuo; Kodama, Takashi; Sakaida, Tsukasa; Yokoi, Sana; Kawasaki, Koichiro; Hasegawa, Yuzo; Hara, Ryusuke

    2014-03-15

    Purpose/Objectives: To assess the effect and toxicity of hypofractionated high-dose intensity modulated radiation therapy (IMRT) with concurrent and adjuvant temozolomide (TMZ) in 46 patients with newly diagnosed glioblastoma multiforme (GBM). Methods and Materials: All patients underwent postsurgical hypofractionated high-dose IMRT. Three layered planning target volumes (PTVs) were contoured. PTV1 was the surgical cavity and residual tumor on T1-weighted magnetic resonance images with 5-mm margins, PTV2 was the area with 15-mm margins surrounding the PTV1, and PTV3 was the high-intensity area on fluid-attenuated inversion recovery images. Irradiation was performed in 8 fractions at total doses of 68, 40, and 32 Gy for PTV1, PTV2, and PTV3, respectively. Concurrent TMZ was given at 75 mg/m{sup 2}/day for 42 consecutive days. Adjuvant TMZ was given at 150 to 200 mg/m{sup 2}/day for 5 days every 28 days. Overall and progression-free survivals were evaluated. Results: No acute IMRT-related toxicity was observed. The dominant posttreatment failure pattern was dissemination. During a median follow-up time of 16.3 months (range, 4.3-80.8 months) for all patients and 23.7 months (range, 12.4-80.8 months) for living patients, the median overall survival was 20.0 months after treatment. Radiation necrosis was diagnosed in 20 patients and was observed not only in the high-dose field but also in the subventricular zone (SVZ). Necrosis in the SVZ was significantly correlated with prolonged survival (hazard ratio, 4.08; P=.007) but caused deterioration in the performance status of long-term survivors. Conclusions: Hypofractionated high-dose IMRT with concurrent and adjuvant TMZ altered the dominant failure pattern from localized to disseminated and prolonged the survival of patients with GBM. Necrosis in the SVZ was associated with better patient survival, but the benefit of radiation to this area remains controversial.

  19. Randomized Phase II Trial of High-Dose Melatonin and Radiation Therapy for RPA Class 2 Patients With Brain Metastases (RTOG 0119)

    SciTech Connect

    Berk, Lawrence . E-mail: Berklb@moffitt.usf.edu; Berkey, Brian; Rich, Tyvin; Hrushesky, William; Gallagher, Michael; Kudrimoti, Mahesh; McGarry, Ronald C.; Suh, John; Mehta, Minesh

    2007-07-01

    Purpose: To determine if high-dose melatonin for Radiation Therapy Oncology Group (RTOG) recursive partitioning analysis (RPA) Class 2 patients with brain metastases improved survival over historical controls, and to determine if the time of day melatonin was given affected its toxicity or efficacy. RTOG 0119 was a phase II randomized trial for this group of patients. Methods and Materials: RTOG RPA Class 2 patients with brain metastases were randomized to 20 mg of melatonin, given either in the morning (8-9 AM) or in the evening (8-9 PM). All patients received radiation therapy (30 Gy in 10 fractions) in the afternoon. Melatonin was continued until neurologic deterioration or death. The primary endpoint was overall survival time. Neurologic deterioration, as reflected by the Mini-Mental Status Examination, was also measured. Results: Neither of the randomized groups had survival distributions that differed significantly from the historic controls of patients treated with whole-brain radiotherapy. The median survivals of the morning and evening melatonin treatments were 3.4 and 2.8 months, while the RTOG historical control survival was 4.1 months. Conclusions: High-dose melatonin did not show any beneficial effect in this group of patients.

  20. Is argon plasma coagulation an effective and safe treatment option for patients with chronic radiation proctitis after high doses of radiotherapy?

    PubMed

    Hortelano, Eduardo; Gómez-Iturriaga, Alfonso; Ortiz-de-Zárate, Roberto; Zaballa, Manuel; Barturen, Ángel; Casquero, Francisco; San-Miguel, Íñigo; Carvajal, Carvajal; Cacicedo, Jon; Del-Hoyo, Olga; Lupiani, Javier; Pérez, Fernando; Bilbao, Pedro

    2014-03-01

    In severe cases refractory to medical treatment, APC appears to be the preferred alternative to control persistent rectal bleeding of patients with chronic radiation proctitis. Although successful outcomes have been demonstrated in patients previously treated with moderate doses of radiotherapy, there is reluctance towards its indication due to the concern of severe adverse events in patients treated with high doses of radiation. The aim of this study was to assess the efficacy and toxicity of APC in the management of bleeding radiationinduced proctitis in patients treated with high doses of radiation for prostate cancer. Data from 30 patients were treated with APC due to chronic radiation proctitis, were reviewed retrospectively. All cases had prostate cancer and 9 of them (30 %) underwent previous radical prostatectomy. The median dose of conformal 3D External Beam Radiotherapy (EBRT) delivered was 74 Gy (range 46-76). Median rectal D1cc and D2cc was 72.5 and 72.4 Gy respectively. Median rectal V70, V60 and V40 was 12, 39.5 and 80 %. Cardiovascular and digestive disease, diabetes, smoking behaviour, lowest haemoglobin and transfusion requirements were recorded. Indications for treatment with APC were anemia and persistent bleeding despite medical treatment. Argon gas flow was set at 1.8 l/min with an electrical power setting of 50 W. Median age of all patients was 69.6 years. The median lowest haemoglobin level was 9.6 g/dL. Median time between completion of radiotherapy and first session of APC was 13 months. Ninety-four therapeutic sessions were performed (median 3 sessions). Median time follow-up was 14.5 months (range 2-61). Complete response with resolved rectal bleeding was achieved in 23 patients (77 %), partial response in 5 (16 %) and no control in 2 (6 %). No patients required transfusion following therapy. Two patients developed long-term (> 6 weeks) grade 2 rectal ulceration and grade 2 rectal incontinence, respectively. The argon plasma coagulation

  1. [A randomized study of intensity-modulated radiation therapy versus three dimensional conformal radiation therapy for pelvic radiation in patients of post-operative treatment with gynecologic malignant tumor].

    PubMed

    Ni, J; Yin, Z M; Yuan, S H; Liu, N F; Li, L; Xu, X X; Lou, H M

    2017-03-25

    Objective: To study the difference between intensity-modulated radiation therapy (IMRT) and three dimensional conformal radiation therapy (3D-CRT) for pelvic radiation of post-operative treatment with gynecologic malignant tumor. Methods: A prospective investigation study was conducted on 183 patients of post-operative patients with whole pelvic radiation therapy of cervical cancer or endometrial cancer in Zhejiang Cancer Hospital [IMRT group (n=85) and 3D-CRT group (n=98)] from Oct. 2015 to Oct. 2016. The two groups received same dose (45 Gy in 25 fractions). Comparison of two groups with radiation dosimetry:the score according to the Radiation Therapy Oncology Group (RTOG) acute radiation injury grading standards before and after radiotherapy reaction, the score from functional assessment of cancer therapy scale-cervix (FACT-Cx) scale and expanded prostate cancer index composite for clinical practice (EPIC-CP) scale were also analyzed. Results: (1) There were no significant effect with age, culture level, family economic condition and ratio of radiochemotherapy between two groups (all P>0.05). (2) Dosimetric comparison for IMRT vs 3D-CRT: the average dose of planning target volume (PTV) decreased (46.1±0.4) vs (46.4±0.5) Gy, V(45) dose percentage increased (95.2±1.0) % vs (93.3±2.0) %, intestinal bag dose of V(4)0 decreased (24.4±6.8) % vs (36.5±15.9) %, rectal V(40) dose percentage decreased (73.9±12.3) % vs (85.4±8.4) %, and lower rectal V(45) dose percentage (32.8±13.4) % vs (71.5±13.7) %, bladder V(40) dose percentage decreased (55.5±13.0) % vs (84.4±13.0) %. Bone marrow V(20) lower: (67.9±5.4) % vs (79.5±6.6) %, V(1)0 lower: (82.1±6.0) % vs (86.3±6.6) %; there were significant differences (all P<0.05). There was no significant difference between the dose of V(45) in the intestinal pouch and bladder (P>0.05). (3) Acute radiation injury classification for IMRT vs 3D-CRT: big or small intestine: Ⅱ-Ⅲ reaction [13% (11/85) vs 24% (24/98); χ(2

  2. Radiation-induced failures and degradation of wireless real-time dosimeter under high-dose-rate irradiation

    NASA Astrophysics Data System (ADS)

    Tsuchiya, K.; Kuroki, K.; Akiba, N.; Kurosawa, K.; Matsumoto, T.; Nishiyama, J.; Harano, H.

    2010-04-01

    Radiation-induced malfunction and degradation of electronic modules in certain operating conditions are described in this report. The cumulative radiation effects on Atmel AVR microcontrollers, and 2.4 GHz and 303 MHz wireless network devices were evaluated under gamma ray irradiation with dose rates of 100, 10 and 3 Gy/h. The radiation-induced malfunctions occurred at doses of 510+/-22 Gy for AVR microcontrollers, and 484+/-111 and 429+/-14 Gy for 2.4 GHz and 303 MHz wireless network devices, respectively, under a 100 Gy/h equivalent dose rate. The degradation of microcontrollers occurred for total ionizing doses between 400 and 600 Gy under X-ray irradiation. In addition, we evaluated the reliability of neutron dosimeters using a standard neutron field. One of the neutron dosimeters gave a reading that was half of the standard field value.

  3. Combined Hydration and Antibiotics with Lisinopril to Mitigate Acute and Delayed High-dose Radiation Injuries to Multiple Organs.

    PubMed

    Fish, Brian L; Gao, Feng; Narayanan, Jayashree; Bergom, Carmen; Jacobs, Elizabeth R; Cohen, Eric P; Moulder, John E; Orschell, Christie M; Medhora, Meetha

    2016-11-01

    The NIAID Radiation and Nuclear Countermeasures Program is developing medical agents to mitigate the acute and delayed effects of radiation that may occur from a radionuclear attack or accident. To date, most such medical countermeasures have been developed for single organ injuries. Angiotensin converting enzyme (ACE) inhibitors have been used to mitigate radiation-induced lung, skin, brain, and renal injuries in rats. ACE inhibitors have also been reported to decrease normal tissue complication in radiation oncology patients. In the current study, the authors have developed a rat partial-body irradiation (leg-out PBI) model with minimal bone marrow sparing (one leg shielded) that results in acute and late injuries to multiple organs. In this model, the ACE inhibitor lisinopril (at ~24 mg m d started orally in the drinking water at 7 d after irradiation and continued to ≥150 d) mitigated late effects in the lungs and kidneys after 12.5-Gy leg-out PBI. Also in this model, a short course of saline hydration and antibiotics mitigated acute radiation syndrome following doses as high as 13 Gy. Combining this supportive care with the lisinopril regimen mitigated overall morbidity for up to 150 d after 13-Gy leg-out PBI. Furthermore, lisinopril was an effective mitigator in the presence of the growth factor G-CSF (100 μg kg d from days 1-14), which is FDA-approved for use in a radionuclear event. In summary, by combining lisinopril (FDA-approved for other indications) with hydration and antibiotics, acute and delayed radiation injuries in multiple organs were mitigated.

  4. Phase II Trial of Radiation Dose Escalation With Conformal External Beam Radiotherapy and High-Dose-Rate Brachytherapy Combined With Long-Term Androgen Suppression in Unfavorable Prostate Cancer: Feasibility Report

    SciTech Connect

    Valero, Jeanette; Cambeiro, Mauricio; Galan, Carlos; Teijeira, Mercedes; Romero, Pilar; Zudaire, Javier; Moreno, Marta; Ciervide, Raquel; Aristu, Jose Javier; Martinez-Monge, Rafael

    2010-02-01

    Purpose: To determine the feasibility of combined long-term luteinizing hormone-releasing hormone agonist-based androgen suppressive therapy (AST) and dose escalation with high-dose-rate (HDR) brachytherapy for high-risk (HRPC) or very-high-risk prostate cancer (VHRPC). Methods and Materials: Between January 2001 and October 2006, 134 patients (median age, 70 years) with either National Comprehensive Cancer Network criteria-defined HRPC (n = 47, 35.1%) or VHRPC (n = 87, 64.9%) were prospectively enrolled in this Phase II trial. Tumor characteristics included a median pretreatment prostate-specific antigen level of 14.6 ng/mL, a median clinical stage of T2c, and a median Gleason score of 7. Three-dimensional conformal radiotherapy (54 Gy in 30 fractions) was followed by HDR brachytherapy (19 Gy in 4 b.i.d. treatments). Androgen suppressive therapy started 0-3 months before three-dimensional conformal radiotherapy and continued for 2 years. Results: One implant was repositioned with a new procedure (0.7%). Five patients (3.7%) discontinued AST at a median of 13 months (range, 6-18 months) because of disease progression (n = 1), hot flashes (n = 2), fatigue (n = 1), and impotence (n = 1). After a median follow-up of 37.4 months (range, 24-90 months), the highest Radiation Therapy Oncology Group-defined late urinary toxicities were Grade 0 in 47.8%, Grade 1 in 38.1%, Grade 2 in 7.5%, and Grade 3 in 6.7% of patients. Maximal late gastrointestinal toxicities were Grade 0 in 73.1%, Grade 1 in 16.4%, Grade 2 in 7.5%, and Grade 3 in 2.9% of patients. There were no Grade 4 or 5 events. Conclusions: Intermediate-term results show that dose escalation with HDR brachytherapy combined with long-term AST is feasible and has a toxicity profile similar to that reported by previous HDR brachytherapy studies.

  5. The susceptibility of TaOx-based memristors to high dose rate ionizing radiation and total ionizing dose

    SciTech Connect

    McLain, Michael Lee; Sheridan, Timothy J.; Hjalmarson, Harold Paul; Mickel, Patrick R.; Hanson, Donald J.; McDonald, Joseph K.; Hughart, David Russell; Marinella, Matthew J.

    2014-11-11

    This paper investigates the effects of high dose rate ionizing radiation and total ionizing dose (TID) on tantalum oxide (TaOx) memristors. Transient data were obtained during the pulsed exposures for dose rates ranging from approximately 5.0 ×107 rad(Si)/s to 4.7 ×108 rad(Si)/s and for pulse widths ranging from 50 ns to 50 μs. The cumulative dose in these tests did not appear to impact the observed dose rate response. Static dose rate upset tests were also performed at a dose rate of ~3.0 ×108 rad(Si)/s. This is the first dose rate study on any type of memristive memory technology. In addition to assessing the tolerance of TaOx memristors to high dose rate ionizing radiation, we also evaluated their susceptibility to TID. The data indicate that it is possible for the devices to switch from a high resistance off-state to a low resistance on-state in both dose rate and TID environments. The observed radiation-induced switching is dependent on the irradiation conditions and bias configuration. Furthermore, the dose rate or ionizing dose level at which a device switches resistance states varies from device to device; the enhanced susceptibility observed in some devices is still under investigation. As a result, numerical simulations are used to qualitatively capture the observed transient radiation response and provide insight into the physics of the induced current/voltages.

  6. Ionizing radiation and autoimmunity: Induction of autoimmune disease in mice by high dose fractionated total lymphoid irradiation and its prevention by inoculating normal T cells

    SciTech Connect

    Sakaguchi, N.; Sakaguchi, S. Scripps Research Institute, La Jolla, CA PRESTO, JRDC, Institute of Phical and Chemical Research, Tsukuba, Ibaraki ); Miyai, K. )

    1992-11-01

    Ionizing radiation can functionally alter the immune system and break self-tolerance. High dose (42.5 Gy), fractionated (2.5 Gy 17 times) total lymphoid irradiation (TLI) on mice caused various organ-specific autoimmune diseases, such as gastritis, thyroiditis, and orchitis, depending on the radiation dosages, the extent of lymphoid irradiation, and the genetic background of the mouse strains. Radiation-induced tissue damage is not the primary cause of the autoimmune disease because irradiation of the target organs alone failed to elicit the autoimmunity and shielding of the organs from irradiation was unable to prevent it. In contrast, irradiation of both the thymus and the peripheral lymphoid organs/tissues was required for efficient induction of autoimmune disease by TLI. TLI eliminated the majority of mature thymocytes and the peripheral T cells for 1 mo, and inoculation of spleen cell, thymocyte, or bone marrow cell suspensions (prepared from syngeneic nonirradiated mice) within 2 wk after TLI effectively prevented the autoimmune development. Depletion of T cells from the inocula abrogated the preventive activity. CD4[sup +] T cells mediated the autoimmune prevention but CD8[sup +] T cells did not. CD4[sup +] T cells also appeared to mediate the TLI-induced autoimmune disease because CD4[sup +] T cells from disease-bearing TLI mice adoptively transferred the autoimmune disease to syngeneic naive mice. Taken together, these results indicate that high dose, fractionated ionizing radiation on the lymphoid organs/tissues can cause autoimmune disease by affecting the T cell immune system, rather than the target self-Ags, presumably by altering T cell-dependent control of self-reactive T cells. 62 refs., 9 figs., 2 tabs.

  7. Three-dimensional marginal separation

    NASA Technical Reports Server (NTRS)

    Duck, Peter W.

    1988-01-01

    The three dimensional marginal separation of a boundary layer along a line of symmetry is considered. The key equation governing the displacement function is derived, and found to be a nonlinear integral equation in two space variables. This is solved iteratively using a pseudo-spectral approach, based partly in double Fourier space, and partly in physical space. Qualitatively, the results are similar to previously reported two dimensional results (which are also computed to test the accuracy of the numerical scheme); however quantitatively the three dimensional results are much different.

  8. Comparative toxicity and micronuclei formation in Tribolium castaneum, Callosobruchus maculatus and Sitophilus oryzae exposed to high doses of gamma radiation.

    PubMed

    Ahmadi, Mehrdad; Mozdarani, Hossein; Abd-Alla, Adly M M

    2015-07-01

    The effects of gamma radiation on mortality and micronucleus formation in Tribolium castaneum Herbst, Callosobruchus maculatus (F.) and Sitophilus oryzae (L.) genital cells were evaluated. Two groups of healthy and active adult insects 1-3 and 8-10 days old were irradiated with various doses (50-200 Gy) gamma ray. Seven days post-irradiation; mortality rates and micronucleus formation were assessed in genital cells of the irradiated insects. The results show that with increasing gamma doses, the mortality rate of each species increased and T. castaneum and S. oryzae showed the low and high sensitivity respectively. It was shown that the micronucleus appearance in the tested insects had correlation with amount and intensity of radiation doses. Moreover our results indicate different levels in the genotoxicity of gamma radiation among the insects' genital cells under study. The frequency of micronuclei in genital cells of 1-3 days old insects exposed to 50 and 200 Gy were 12.6 and 38.8 Mn/1000 cells in T. castaneum, 20.8 and 46.8 Mn/1000 cells in C. maculatus and 16.8 and 57.2 Mn/1000 cells in S. oryzae respectively. A high sensitivity of the genital cells to irradiation exposure was seen in S. oryzae correlated with its high mortality rate compared with the other two species. These results might be indicative of inflicting chromosomal damage expressed as micronucleus in high mortality rates observed in the pest population; an indication of genotoxic effects of radiation on the studied species.

  9. Three dimensional colorimetric assay assemblies

    SciTech Connect

    Charych, D.; Reichart, A.

    2000-06-27

    A direct assay is described using novel three-dimensional polymeric assemblies which change from a blue to red color when exposed to an analyte, in one case a flu virus. The assemblies are typically in the form of liposomes which can be maintained in a suspension, and show great intensity in their color changes. Their method of production is also described.

  10. Three dimensional colorimetric assay assemblies

    DOEpatents

    Charych, Deborah; Reichart, Anke

    2000-01-01

    A direct assay is described using novel three-dimensional polymeric assemblies which change from a blue to red color when exposed to an analyte, in one case a flu virus. The assemblies are typically in the form of liposomes which can be maintained in a suspension, and show great intensity in their color changes. Their method of production is also described.

  11. Three-Dimensional Lissajous Figures.

    ERIC Educational Resources Information Center

    D'Mura, John M.

    1989-01-01

    Described is a mechanically driven device for generating three-dimensional harmonic space figures with different frequencies and phase angles on the X, Y, and Z axes. Discussed are apparatus, viewing stereo pairs, equations of motion, and using space figures in classroom. (YP)

  12. Three-dimensional stellarator codes

    PubMed Central

    Garabedian, P. R.

    2002-01-01

    Three-dimensional computer codes have been used to develop quasisymmetric stellarators with modular coils that are promising candidates for a magnetic fusion reactor. The mathematics of plasma confinement raises serious questions about the numerical calculations. Convergence studies have been performed to assess the best configurations. Comparisons with recent data from large stellarator experiments serve to validate the theory. PMID:12140367

  13. Creating Three-Dimensional Scenes

    ERIC Educational Resources Information Center

    Krumpe, Norm

    2005-01-01

    Persistence of Vision Raytracer (POV-Ray), a free computer program for creating photo-realistic, three-dimensional scenes and a link for Mathematica users interested in generating POV-Ray files from within Mathematica, is discussed. POV-Ray has great potential in secondary mathematics classrooms and helps in strengthening students' visualization…

  14. Three-Dimensional Lissajous Figures.

    ERIC Educational Resources Information Center

    D'Mura, John M.

    1989-01-01

    Described is a mechanically driven device for generating three-dimensional harmonic space figures with different frequencies and phase angles on the X, Y, and Z axes. Discussed are apparatus, viewing stereo pairs, equations of motion, and using space figures in classroom. (YP)

  15. Creating Three-Dimensional Scenes

    ERIC Educational Resources Information Center

    Krumpe, Norm

    2005-01-01

    Persistence of Vision Raytracer (POV-Ray), a free computer program for creating photo-realistic, three-dimensional scenes and a link for Mathematica users interested in generating POV-Ray files from within Mathematica, is discussed. POV-Ray has great potential in secondary mathematics classrooms and helps in strengthening students' visualization…

  16. Hydrodynamic instability growth of three-dimensional modulations in radiation-driven implosions with "low-foot" and "high-foot" drives at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Smalyuk, V. A.; Weber, C. R.; Robey, H. F.; Casey, D. T.; Chen, K.-C.; Clark, D. S.; Farrell, M.; Felker, S.; Field, J. E.; Haan, S. W.; Hammel, B. A.; Hamza, A. V.; Hoover, D.; Kroll, J. J.; Landen, O. L.; MacPhee, A. G.; Martinez, D.; Nikroo, A.; Rice, N.

    2017-04-01

    Hydrodynamic instability growth has been studied using three-dimensional (3-D) broadband modulations by comparing "high-foot" and "low-foot" spherical plastic (CH) capsule implosions at the National Ignition Facility (NIF) [E. M. Campbell et al., AIP Conf. Proc. 429, 3 (1998)]. The initial perturbations included capsule outer-surface roughness and capsule-mounting membranes ("tents") that were similar to those used in a majority of implosions on NIF. The tents with thicknesses of 31-nm, 46-nm, and 109-nm were used in the experiments. The outer-surface roughness in the "low-foot" experiment was similar to the standard specification, while it was increased by ˜4 times in the "high-foot" experiment to compensate for the reduced growth. The ablation-front instability growth was measured using a Hydrodynamic Growth Radiography platform at a convergence ratio of ˜3. The dominant capsule perturbations, generated by the tent mountings, had measured perturbation amplitudes comparable to the capsule thickness with the "low-foot" drive. These tent perturbations were reduced by ˜3 to 10 times in implosions with the "high-foot" drive. Unexpectedly, the measured perturbations with initially thinner tents were either larger or similar to the measured perturbations with thicker tents for both "high-foot" and "low-foot" drives. While the measured instability growth of 3-D broadband perturbations was also significantly reduced by ˜5 to 10 times with the "high-foot" drive, compared to the "low-foot" drive, the growth mitigation was stronger than expected based on previous "growth-factor" results measured with two-dimensional modulations [D. T. Casey et al., Phys. Rev. E 90, 011102 (2014)]. One of the hypotheses to explain the results is based on the 3-D modulations of the oxygen content in the bulk of the capsule having a stronger effect on the overall growth of capsule perturbations than the outer-surface capsule roughness.

  17. Three-dimensional ultrasound system for guided breast brachytherapy.

    PubMed

    De Jean, Paul; Beaulieu, Luc; Fenster, Aaron

    2009-11-01

    Breast-conserving surgery combined with subsequent radiation therapy is a standard procedure in breast cancer treatment. The disadvantage of whole-breast beam irradiation is that it requires 20-25 treatment days, which is inconvenient for patients with limited mobility or who reside far from the treatment center. However, interstitial high-dose-rate (HDR) brachytherapy is an irradiation method requiring only 5 treatment days and that delivers a lower radiation dose to the surrounding healthy tissue. It involves delivering radiation through 192Ir seeds placed inside the catheters, which are inserted into the breast. The catheters are attached to a HDR afterloader, which controls the seed placement within the catheters and irradiation times to deliver the proper radiation dose. One disadvantage of using HDR brachytherapy is that it requires performing at least one CT scan during treatment planning. The procedure at our institution involves the use of two CT scans. Performing CT scans requires moving the patient from the brachytherapy suite with catheters inserted in their breasts. One alternative is using three-dimensional ultrasound (3DUS) to image the patient. In this study, the authors developed a 3DUS translation scanning system for use in breast brachytherapy. The new system was validated using CT, the current clinical standard, to image catheters in a breast phantom. Once the CT and 3DUS images were registered, the catheter trajectories were then compared. The results showed that the average angular separation between catheter trajectories was 2.4 degrees, the average maximum trajectory separation was 1.0 mm, and the average mean trajectory separation was found to be 0.7 mm. In this article, the authors present the 3DUS translation scanning system's capabilities as well as its potential to be used as the primary treatment planning imaging modality in breast brachytherapy.

  18. Three-dimensional ultrasound system for guided breast brachytherapy

    SciTech Connect

    De Jean, Paul; Beaulieu, Luc; Fenster, Aaron

    2009-11-15

    Breast-conserving surgery combined with subsequent radiation therapy is a standard procedure in breast cancer treatment. The disadvantage of whole-breast beam irradiation is that it requires 20-25 treatment days, which is inconvenient for patients with limited mobility or who reside far from the treatment center. However, interstitial high-dose-rate (HDR) brachytherapy is an irradiation method requiring only 5 treatment days and that delivers a lower radiation dose to the surrounding healthy tissue. It involves delivering radiation through {sup 192}Ir seeds placed inside the catheters, which are inserted into the breast. The catheters are attached to a HDR afterloader, which controls the seed placement within the catheters and irradiation times to deliver the proper radiation dose. One disadvantage of using HDR brachytherapy is that it requires performing at least one CT scan during treatment planning. The procedure at our institution involves the use of two CT scans. Performing CT scans requires moving the patient from the brachytherapy suite with catheters inserted in their breasts. One alternative is using three-dimensional ultrasound (3DUS) to image the patient. In this study, the authors developed a 3DUS translation scanning system for use in breast brachytherapy. The new system was validated using CT, the current clinical standard, to image catheters in a breast phantom. Once the CT and 3DUS images were registered, the catheter trajectories were then compared. The results showed that the average angular separation between catheter trajectories was 2.4 deg., the average maximum trajectory separation was 1.0 mm, and the average mean trajectory separation was found to be 0.7 mm. In this article, the authors present the 3DUS translation scanning system's capabilities as well as its potential to be used as the primary treatment planning imaging modality in breast brachytherapy.

  19. Volumetric index of Tl-201 uptake in symptomatic patients after high - dose radiation treatment for high-grade gliomas

    SciTech Connect

    Carvalho, P.A.; Garada, B.M.; Loeffler, J.S. |

    1995-05-01

    To verify the utility of a volumetric estimation of Tl-201 uptake in the context of possible astrocytoma recurrence after surgery, radiotherapy plus stereotactic boost (radiosurgery/brachitherapy), we analyzed sequential Tl-201/Tc99m-HMPAO brain SPECT studies of 28 patients (18 m/10 f). These were categorized as having tumor mass recurrence (TM), infiltrating tumor cells but no definite tumor mass (IT), or radiation changes and necrosis (RCN) after stereotactic biopsy and/or craniotomy. SPECT studies were obtained with a high-resolution dedicated gamma camera (CERASPECT, Digital Scinitgraphics, Inc.) and image acquisition was performed after intravenous Tl-201 (18.5 MBq) and Tc-99m HMPAO (740 MBq). In order to include relevant information about tumor burden, a volumetric index of Tl-201 uptake was expressed in cm{sup 3} related to voxel size (4.6 x 10{sup -3} cc) within an elliptical ROI that included the tumor area. Only voxels with a threshold {ge} 2 in relation to the average scalp Tl-201 uptake were included and this total number of voxels expressed in cc was compared to previously established maximal tumor/scalp Tl-201 uptake ratios (T/S) and histopathology. Results are presented as the median (min-max) and differences were considered significant for p<0.05. Differences were significant between all groups for both ratios and volume indices and correlation between the two variables was 0.90. In conclusion, the volumetric index of Tl-201 is similar to the maximal Tl-201 T/S ratios in discriminating tumor recurrence and radiation necrosis, suggesting a future role for the volumetric index estimation in the evaluation of treatment efficacy and patient follow-up.

  20. Antitransforming growth factor-{beta} antibody 1D11 ameliorates normal tissue damage caused by high-dose radiation

    SciTech Connect

    Anscher, Mitchell S. . E-mail: ansch001@notes.duke.edu; Thrasher, Bradley; Rabbani, Zahid; Teicher, Beverly; Vujaskovic, Zeljko

    2006-07-01

    Purpose The aim of this study was to determine whether a neutralizing transforming growth factor-{beta} (TGF{beta}) antibody can prevent radiation (RT) induced lung injury. Methods and Materials Fractionated and sham right lung irradiation in Fischer 344 rats was delivered to assess the radioprotective effect of the antibodies. Animals were divided into the following groups: (1) control (sham RT, control antibody 13C4); (2) RT (800cGy x 5)+13C4); (3) RT + 0.1 mg/kg 1D11 anti-TGF{beta} antibody; and (4) RT + 1 mg/kg 1D11 antibody. Antibodies were intraperitoneally administered immediately after the last fraction of RT. Animals were sacrificed at 6 and 26 weeks after irradiation. Lungs were assessed for histologic changes, activation of macrophages, expression/activation of TGF{beta} and its signal transduction pathway. Results At 6 weeks post-RT, there was a significant reduction in macrophage accumulation (p = 0.041), alveolar wall thickness (p = 0.0003), and TGF-{beta} activation (p = 0.032) in animals receiving 1.0 mg/kg 1D11 vs. in the control group. However, at 6 weeks, the low dose of 1D11 antibody (0.1 mg/kg) failed to produce any significant changes. At 6 months post-RT, radioprotection is apparent for the group receiving 1.0 mg/kg 1D11, with activated macrophages (p = 0.037), alveolar wall thickness (p = 0.0002), TGF{beta} activation (p = 0.002) and its signal transduction proteins (p < 0.05) compared with the control group. Conclusions Administration of a single dose of 1.0 mg/kg of the anti-TGF{beta} antibody 1D11 resulted in decreased morphologic changes, inflammatory response, and reduced expression and activation of TGF{beta} 6 weeks and 6 months after 40 Gy to the right hemithorax. Targeting the TGF{beta} pathway may be a useful strategy to prevent radiation-induced lung injury.

  1. High-Dose Split-Course Radiation Therapy for Anal Cancer: Outcome Analysis Regarding the Boost Strategy (CORS-03 Study)

    SciTech Connect

    Hannoun-Levi, Jean-Michel; Ortholan, Cecile; Resbeut, Michel; Teissier, Eric; Ronchin, Philippe; Cowen, Didier; Zaccariotto, Audrey; Benezery, Karen; Francois, Eric; Salem, Naji; Ellis, Steve; Azria, David; Gerard, Jean-Pierre

    2011-07-01

    Purpose: To retrospectively assess the clinical outcome in anal cancer patients treated with split-course radiation therapy and boosted through external-beam radiation therapy (EBRT) or brachytherapy (BCT). Methods and Materials: From January 2000 to December 2004, a selected group (162 patients) with invasive nonmetastatic anal squamous cell carcinoma was studied. Tumor staging reported was T1 = 31 patients (19%), T2 = 77 patients (48%), T3 = 42 patients (26%), and T4= 12 patients (7%). Lymph node status was N0-1 (86%) and N2-3 (14%). Patients underwent a first course of EBRT: mean dose 45.1 Gy (range, 39.5-50) followed by a boost: mean dose 17.9 Gy (range, 8-25) using EBRT (76 patients, 47%) or BCT (86 patients, 53%). All characteristics of patients and tumors were well balanced between the BCT and EBRT groups. Results: The mean overall treatment time (OTT) was 82 days (range, 45-143) and 67 days (range, 37-128) for the EBRT and BCT groups, respectively (p < 0.001). The median follow-up was 62 months (range, 2-108). The 5-year cumulative rate of local recurrence (CRLR) was 21%. In the univariate analysis, the prognostic factors for CRLR were as follows: T stage (T1-2 = 15% vs. T3-4 = 36%, p = 0.03), boost technique (BCT = 12% vs. EBRT = 33%, p = 0.002) and OTT (OTT <80 days = 14%, OTT {>=}80 days = 34%, p = 0.005). In the multivariate analysis, BCT boost was the unique prognostic factor (hazard ratio = 0.62 (0.41-0.92). In the subgroup of patients with OTT <80 days, the 5-year CRLR was significantly increased with the BCT boost (BC = 9% vs. EBRT = 28%, p = 0.03). In the case of OTT {>=}80 days, the 5-year CRLR was not affected by the boost technique (BCT = 29% vs. EBRT = 38%, p = 0.21). Conclusion: In anal cancer, when OTT is <80 days, BCT boost is superior to EBRT boost for CRLR. These results suggest investigating the benefit of BCT boost in prospective trials.

  2. Tomotherapy after pleurectomy/decortication or biopsy for malignant pleural mesothelioma allows the delivery of high dose of radiation in patients with intact lung.

    PubMed

    Minatel, Emilio; Trovo, Marco; Polesel, Jerry; Rumeileh, Imad Abu; Baresic, Tania; Bearz, Alessandra; Del Conte, Alessandro; Franchin, Giovanni; Gobitti, Carlo; Drigo, Annalisa; Dassie, Andrea; Pagan, Vittore; Trovo, Mauro G

    2012-12-01

    This study aimed to assess the safety of high doses of radiation delivered with tomotherapy to the intact lung after radical pleurectomy/decortication or biopsy for malignant pleural mesothelioma (MPM). Twenty-eight patients were enrolled in this prospective study and underwent adjuvant or definitive tomotherapy after radical pleurectomy/decortication (n = 20) or pleural biopsy (n = 8) for MPM. The dose prescribed to the planning target volume, defined as the entire hemithorax, including chest-wall incisions and drain sites and excluding the intact lung, was 50 Gy delivered in 25 fractions. All patients underwent fluorodeoxyglucose-positron emission tomography for staging after surgery. Any fluorodeoxyglucose-avid areas or regions of particular concern for residual disease were given a simultaneous boost of radiotherapy to 60 Gy. Specific lung dosimetric parameters were reported. Toxicity was graded using the modified Common Toxicity Criteria version 3.0. The median follow-up was of 19 months (range, 6-29 months). Five patients (17.8%) experienced severe respiratory symptoms corresponding to grade 2 pneumonitis in three cases, and grade 3 pneumonitis in two cases. No fatal respiratory toxicity was reported. Controlateral lung V5 was strongly correlated with the risk of pneumonitis. Patients who developed grade 2 and 3 pneumonitis had a higher controlateral lung V5 (mean V5=32%) than those without pneumonitis (mean V5=17%) (p=0.002). Other two grade 3 toxicities were registered: one severe pain to the chest wall, and one severe thrombocytopenia. Tomotherapy allows the safe delivery of high dose of radiation to the hemithorax of MPM patients with intact lung.

  3. Intensity-modulated radiotherapy improves lymph node coverage and dose to critical structures compared with three-dimensional conformal radiation therapy in clinically localized prostate cancer

    SciTech Connect

    Wang-Chesebro, Alice . E-mail: awang@radonc17.ucsf.edu; Xia Ping; Coleman, Joy; Akazawa, Clayton C.; Roach, Mack

    2006-11-01

    Purpose: The aim of this study was to quantify gains in lymph node coverage and critical structure dose reduction for whole-pelvis (WP) and extended-field (EF) radiotherapy in prostate cancer using intensity-modulated radiotherapy (IMRT) compared with three-dimensional conformal radiotherapy (3DCRT) for the first treatment phase of 45 Gy in the concurrent treatment of lymph nodes and prostate. Methods and Materials: From January to August 2005, 35 patients with localized prostate cancer were treated with pelvic IMRT; 7 had nodes defined up to L5-S1 (Group 1), and 28 had nodes defined above L5-S1 (Group 2). Each patient had 2 plans retrospectively generated: 1 WP 3DCRT plan using bony landmarks, and 1 EF 3DCRT plan to cover the vascular defined volumes. Dose-volume histograms for the lymph nodes, rectum, bladder, small bowel, and penile bulb were compared by group. Results: For Group 1, WP 3DCRT missed 25% of pelvic nodes with the prescribed dose 45 Gy and missed 18% with the 95% prescribed dose 42.75 Gy, whereas WP IMRT achieved V{sub 45Gy} = 98% and V{sub 42.75Gy} = 100%. Compared with WP 3DCRT, IMRT reduced bladder V{sub 45Gy} by 78%, rectum V{sub 45Gy} by 48%, and small bowel V{sub 45Gy} by 232 cm{sup 3}. EF 3DCRT achieved 95% coverage of nodes for all patients at high cost to critical structures. For Group 2, IMRT decreased bladder V{sub 45Gy} by 90%, rectum V{sub 45Gy} by 54% and small bowel V{sub 45Gy} by 455 cm{sup 3} compared with EF 3DCRT. Conclusion: In this study WP 3DCRT missed a significant percentage of pelvic nodes. Although EF 3DCRT achieved 95% pelvic nodal coverage, it increased critical structure doses. IMRT improved pelvic nodal coverage while decreasing dose to bladder, rectum, small bowel, and penile bulb. For patients with extended node involvement, IMRT especially decreases small bowel dose.

  4. Mitigation Effect of an FGF-2 Peptide on Acute Gastrointestinal Syndrome After High-Dose Ionizing Radiation

    SciTech Connect

    Zhang Lurong; Sun Weimin; Wang Jianjun; Zhang Mei; Yang Shanmin; Tian Yeping; Vidyasagar, Sadasivan; Pena, Louis A.; Zhang Kunzhong; Cao Yongbing; Yin Liangjie; Wang Wei; Zhang Lei; Schaefer, Katherine L.; Saubermann, Lawrence J.; Swarts, Steven G.; Fenton, Bruce M.; Keng, Peter C.; Okunieff, Paul

    2010-05-01

    Purpose: Acute gastrointestinal syndrome (AGS) resulting from ionizing radiation causes death within 7 days. Currently, no satisfactory agent exists for mitigation of AGS. A peptide derived from the receptor binding domain of fibroblast growth factor 2 (FGF-P) was synthesized and its mitigation effect on AGS was examined. Methods and Materials: A subtotal body irradiation (sub-TBI) model was created to induce gastrointestinal (GI) death while avoiding bone marrow death. After 10.5 to 16 Gy sub-TBI, mice received an intramuscular injection of FGF-P (10 mg/kg/day) or saline (0.2 ml/day) for 5 days; survival (frequency and duration) was measured. Crypt cells and their proliferation were assessed by hematoxylin, eosin, and BrdU staining. In addition, GI hemoccult score, stool formation, and plasma levels of endotoxin, insulin, amylase, interleukin (IL)-6, keratinocyte-derived chemokine (KC) monocyte chemoattractant protein 1 (MCP-1) and tumor necrosis factor (TNF)-alpha were evaluated. Results: Treatment with FGF-P rescued a significant fraction of four strains of mice (33-50%) exposed to a lethal dose of sub-TBI. Use of FGF-P improved crypt survival and repopulation and partially preserved or restored GI function. Furthermore, whereas sub-TBI increased plasma endotoxin levels and several pro-inflammation cytokines (IL-6, KC, MCP-1, and TNF-alpha), FGF-P reduced these adverse responses. Conclusions: The study data support pursuing FGF-P as a mitigator for AGS.

  5. Three-dimensional conformal versus non-graphic radiation treatment planning for apocrine gland adenocarcinoma of the anal sac in 18 dogs (2002-2007).

    PubMed

    Keyerleber, M A; Gieger, T L; Erb, H N; Thompson, M S; McEntee, M C

    2012-12-01

    Differences in dose homogeneity and irradiated volumes of target and surrounding normal tissues between 3D conformal radiation treatment planning and simulated non-graphic manual treatment planning were evaluated in 18 dogs with apocrine gland adenocarcinoma of the anal sac. Overall, 3D conformal treatment planning resulted in more homogenous dose distribution to target tissues with lower hot spots and dose ranges. Dose homogeneity and guarantee of not under-dosing target tissues with 3D conformal planning came at the cost, however, of delivering greater mean doses of radiation and of irradiating greater volumes of surrounding normal tissue structures. © 2011 Blackwell Publishing Ltd.

  6. Hypofractionated High-Dose Radiation Therapy for Prostate Cancer: Long-Term Results of a Multi-Institutional Phase II Trial

    SciTech Connect

    Fonteyne, Valerie; Soete, Guy; Arcangeli, Stefano; De Neve, Wilfried; Rappe, Bernard; Storme, Guy; Strigari, Lidia; Arcangeli, Giorgio; De Meerleer, Gert

    2012-11-15

    Purpose: To report late gastrointestinal (GI) and genitourinary (GU) toxicity, biochemical and clinical outcomes, and overall survival after hypofractionated radiation therapy for prostate cancer (PC). Methods and Materials: Three institutions included 113 patients with T1 to T3N0M0 PC in a phase II study. Patients were treated with 56 Gy in 16 fractions over 4 weeks. Late toxicity was scored using Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria extended with additional symptoms. Biochemical outcome was reported according to the Phoenix definition for biochemical failure. Results: The incidence of late GI and GU toxicity was low. The 3-year actuarial risk of developing late GU and GI toxicity of grade {>=}2 was 13% and 8% respectively. Five-year biochemical non-evidence of disease (bNED) was 94%. Risk group, T stage, and deviation from planned hormone treatment were significant predictive factors for bNED. Deviation from hormone treatment remained significant in multivariate analysis. Five-year clinical non evidence of disease and overall survival was 95% and 91% respectively. No patient died from PC. Conclusions: Hypofractionated high-dose radiation therapy is a valuable treatment option for patients with PC, with excellent biochemical and clinical outcome and low toxicity.

  7. Comparison of Radiation Exposure in Lumbar Pedicle Screw Placement With Fluoroscopy Vs Computer-Assisted Image Guidance With Intraoperative Three-Dimensional Imaging

    PubMed Central

    Smith, Harvey E; Welsch, Matthew D; Sasso, Rick C; Vaccaro, Alexander R

    2008-01-01

    Background/Objective: Little is known about the long-term effects of chronic exposure to ionizing radiation. Studies have shown that spine surgeons may be exposed to significantly more radiation than that observed in surgery on the appendicular skeleton. Computer-assisted image guidance systems have been shown in preliminary studies to enable accurate instrumentation of the spine. Computer-assisted image guidance systems may have significant application to the surgical management of spinal trauma and deformity. The objective of this study was to compare C-arm fluoroscopy and computer-assisted image guidance in terms of radiation exposure to the operative surgeon when placing pedicle screw-rod constructs in cadaver specimens. Methods: Twelve single-level (2 contiguous vertebral bodies) lumbar pedicle screw-rod constructs (48 screws) in 4 fresh cadavers were placed using standard C-arm fluoroscopy and computer-assisted image guidance (Stealth Station with Iso-C3D). Pedicle screw-rod constructs were placed at L1–L2, L3–L4, and L5–S1 in 4 fresh cadaver specimens. Imaging was alternated between C-arm fluoroscopy and computer-assisted image guidance with StealthStation Iso-C3D. Radiation exposure was measured using ring and badge dosimeters to monitor the thyroid, torso, and index finger. Postprocedure CT scans were obtained to judge accuracy of screw placement. Results: Mean radiation exposure to the torso was 4.33 ± 2.66 mRem for procedures performed with standard fluoroscopy and 0.33 ± 0.82 mRem for procedures performed with computer-assisted image guidance. This difference was statistically significant (P = 0.012). Radiation exposure to the index finger and thyroid was negligible for all procedures. The accuracy of screw placement was similar for both techniques. Conclusions: Computer-assisted image guidance systems allow for the safe and accurate placement of pedicle screw-rod constructs with a significant reduction in exposure to ionizing radiation to the

  8. Three-dimensional perspective visualization

    NASA Technical Reports Server (NTRS)

    Hussey, Kevin

    1991-01-01

    It was demonstrated that image processing computer graphic techniques can provide an effective means of physiographic analysis of remotely sensed regions through the use of three-dimensional perspective rendering. THe methods used to simulate and animate three-dimensional surfaces from two-dimensional imagery and digital elevation models are explained. A brief historic look at JPL's efforts in this field and several examples of animations, illustrating the evolution of these techniques from 1985, are shown. JPL's current research in this area is discussed along with examples of technology transfer and potential commercial application. The software is part of the VICAR (Video Image Communication and Retrieval) image processing system which was developed at the Multimission Image Processing Laboratory of JPL.

  9. Randomized Trial Comparing Conventional-Dose With High-Dose Conformal Radiation Therapy in Early-Stage Adenocarcinoma of the Prostate: Long-Term Results From Proton Radiation Oncology Group/American College of Radiology 95-09

    PubMed Central

    Zietman, Anthony L.; Bae, Kyounghwa; Slater, Jerry D.; Shipley, William U.; Efstathiou, Jason A.; Coen, John J.; Bush, David A.; Lunt, Margie; Spiegel, Daphna Y.; Skowronski, Rafi; Jabola, B. Rodney; Rossi, Carl J.

    2010-01-01

    Purpose To test the hypothesis that increasing radiation dose delivered to men with early-stage prostate cancer improves clinical outcomes. Patients and Methods Men with T1b-T2b prostate cancer and prostate-specific antigen ≤ 15 ng/mL were randomly assigned to a total dose of either 70.2 Gray equivalents (GyE; conventional) or 79.2 GyE (high). No patient received androgen suppression therapy with radiation. Local failure (LF), biochemical failure (BF), and overall survival (OS) were outcomes. Results A total of 393 men were randomly assigned, and median follow-up was 8.9 years. Men receiving high-dose radiation therapy were significantly less likely to have LF, with a hazard ratio of 0.57. The 10-year American Society for Therapeutic Radiology and Oncology BF rates were 32.4% for conventional-dose and 16.7% for high-dose radiation therapy (P < .0001). This difference held when only those with low-risk disease (n = 227; 58% of total) were examined: 28.2% for conventional and 7.1% for high dose (P < .0001). There was a strong trend in the same direction for the intermediate-risk patients (n = 144; 37% of total; 42.1% v 30.4%, P = .06). Eleven percent of patients subsequently required androgen deprivation for recurrence after conventional dose compared with 6% after high dose (P = .047). There remains no difference in OS rates between the treatment arms (78.4% v 83.4%; P = .41). Two percent of patients in both arms experienced late grade ≥ 3 genitourinary toxicity, and 1% of patients in the high-dose arm experienced late grade ≥ 3 GI toxicity. Conclusion This randomized controlled trial shows superior long-term cancer control for men with localized prostate cancer receiving high-dose versus conventional-dose radiation. This was achieved without an increase in grade ≥ 3 late urinary or rectal morbidity. PMID:20124169

  10. Sexual Functioning Among Endometrial Cancer Patients Treated With Adjuvant High-Dose-Rate Intra-Vaginal Radiation Therapy

    SciTech Connect

    Damast, Shari; Alektiar, Kaled M.; Goldfarb, Shari; Eaton, Anne; Patil, Sujata; Mosenkis, Jeffrey; Bennett, Antonia; Atkinson, Thomas; Jewell, Elizabeth; Leitao, Mario; Barakat, Richard; Carter, Jeanne; Basch, Ethan

    2012-10-01

    Purpose: We used the Female Sexual Function Index (FSFI) to investigate the prevalence of sexual dysfunction (SD) and factors associated with diminished sexual functioning in early stage endometrial cancer (EC) patients treated with simple hysterectomy and adjuvant brachytherapy. Methods and Materials: A cohort of 104 patients followed in a radiation oncology clinic completed questionnaires to quantify current levels of sexual functioning. The time interval between hysterectomy and questionnaire completion ranged from <6 months to >5 years. Multivariate regression was performed using the FSFI as a continuous variable (score range, 1.2-35.4). SD was defined as an FSFI score of <26, based on the published validation study. Results: SD was reported by 81% of respondents. The mean ({+-} standard deviation) domain scores in order of highest-to-lowest functioning were: satisfaction, 2.9 ({+-}2.0); orgasm, 2.5 ({+-}2.4); desire, 2.4 ({+-}1.3); arousal, 2.2 ({+-}2.0); dryness, 2.1 ({+-}2.1); and pain, 1.9 ({+-}2.3). Compared to the index population in which the FSFI cut-score was validated (healthy women ages 18-74), all scores were low. Compared to published scores of a postmenopausal population, scores were not statistically different. Multivariate analysis isolated factors associated with lower FSFI scores, including having laparotomy as opposed to minimally invasive surgery (effect size, -7.1 points; 95% CI, -11.2 to -3.1; P<.001), lack of vaginal lubricant use (effect size, -4.4 points; 95% CI, -8.7 to -0.2, P=.040), and short time interval (<6 months) from hysterectomy to questionnaire completion (effect size, -4.6 points; 95% CI, -9.3-0.2; P=.059). Conclusions: The rate of SD, as defined by an FSFI score <26, was prevalent. The postmenopausal status of EC patients alone is a known risk factor for SD. Additional factors associated with poor sexual functioning following treatment for EC included receipt of laparotomy and lack of vaginal lubricant use.

  11. Facial three-dimensional morphometry.

    PubMed

    Ferrario, V F; Sforza, C; Poggio, C E; Serrao, G

    1996-01-01

    Three-dimensional facial morphometry was investigated in a sample of 40 men and 40 women, with a new noninvasive computerized method. Subjects ranged in age between 19 and 32 years, had sound dentitions, and no craniocervical disorders. For each subject, 16 cutaneous facial landmarks were automatically collected by a system consisting of two infrared camera coupled device (CCD) cameras, real time hardware for the recognition of markers, and software for the three-dimensional reconstruction of landmarks' x, y, z coordinates. From these landmarks, 15 linear and 10 angular measurements, and four linear distance ratios were computed and averaged for sex. For all angular values, both samples showed a narrow variability and no significant gender differences were demonstrated. Conversely, all the linear measurements were significantly higher in men than in women. The highest intersample variability was observed for the measurements of facial height (prevalent vertical dimension), and the lowest for the measurements of facial depth (prevalent horizontal dimension). The proportions of upper and lower face height relative to the anterior face height showed a significant sex difference. Mean values were in good agreement with literature data collected with traditional methods. The described method allowed the direct and noninvasive calculation of three-dimensional linear and angular measurements that would be usefully applied in clinics as a supplement to the classic x-ray cephalometric analyses.

  12. Three-dimensional ultrasonic colloidal crystals

    NASA Astrophysics Data System (ADS)

    Caleap, Mihai; Drinkwater, Bruce W.

    2016-05-01

    Colloidal assembly represents a powerful method for the fabrication of functional materials. In this article, we describe how acoustic radiation forces can guide the assembly of colloidal particles into structures that serve as microscopic elements in novel acoustic metadevices or act as phononic crystals. Using a simple three-dimensional orthogonal system, we show that a diversity of colloidal structures with orthorhombic symmetry can be assembled with megahertz-frequency (MHz) standing pressure waves. These structures allow rapid tuning of acoustic properties and provide a new platform for dynamic metamaterial applications.

  13. Three dimensional data-assimilative VERB-code simulations of the Earth's radiation belts: Reanalysis during the Van Allen Probe era, and operational forecasting

    NASA Astrophysics Data System (ADS)

    Kellerman, Adam; Shprits, Yuri; Podladchikova, Tatiana; Kondrashov, Dmitri

    2016-04-01

    The Versatile Electron Radiation Belt (VERB) code 2.0 models the dynamics of radiation-belt electron phase space density (PSD) in Earth's magnetosphere. Recently, a data-assimilative version of this code has been developed, which utilizes a split-operator Kalman-filtering approach to solve for electron PSD in terms of adiabatic invariants. A new dataset based on the TS07d magnetic field model is presented, which may be utilized for analysis of past geomagnetic storms, and for initial and boundary conditions in running simulations. Further, a data-assimilative forecast model is introduced, which has the capability to forecast electron PSD several days into the future, given a forecast Kp index. The model assimilates an empirical model capable of forecasting the conditions at geosynchronous orbit. The model currently runs in real time and a forecast is available to view online http://rbm.epss.ucla.edu.

  14. SU-E-T-514: Simultaneously Determination of Radiation Isocentricity of Gantry, Collimator and Couch Using a Commercial Three-Dimensional Dosimetry QA Apparatus

    SciTech Connect

    Yan, S; Song, H; Wu, Q

    2014-06-01

    Purpose: Radiation isocentricity is an important benchmark for a LINAC and is typically determined by 3 separate film star-shots. We developed a technique to simultaneously determine the radiation isocenter of gantry, collimator and couch with a commercial 3D QA apparatus. Methods: The ArcCHECK from SunNuclear was used on two LINACs. It was aligned with room lasers. For gantry rotation, collimator and couch were set to zero and gantry was placed to 0, 49, 213 and 311 degrees. Similarly, a set of collimator/couch angles were chosen with the other two axes at neutral positions. The measured dose matrices were analyzed by an in-house MATLAB program. For each shot, the central axis was determined by computing the FWHM of the diode arrays. The largest inscribed circle from these central axis lines was used to determine isocenter: the radius as the benchmark of isocentricity and the coordinates of the center as the discrepancy of radiation isocenter to the origin defined by lasers. To validate the method, the couch was shifted by ~5 mm in all three directions and measurements were repeated. Results: The radius of the largest inscribed circle for gantry, collimator and couch are (0.3, 0.5, 0.2) mm for one LINAC and (0.2, 0.3, 0.1) mm for the other, in agreement with the film star-shots at annual QA. The discrepancies of radiation isocenter are generally within 1 mm, except gantry rotation on one LINAC due to the drift of foot laser. The differences in positions detected are consistent with the intentional predefined shift. Conclusion: We have demonstrated a technique for the simultaneous measurement of gantry, collimator, and couch isocentricity with a set of carefully chosen irradiation parameters based on the specific construction geometry of the 3D detector ArcCheck. This can replace the standard film star-shots. The future work includes improving operation efficiency.

  15. Development of a minipig model for lung injury induced by a single high-dose radiation exposure and evaluation with thoracic computed tomography

    PubMed Central

    Lee, Jong-Geol; Park, Sunhoo; Bae, Chang-Hwan; Jang, Won-Suk; Lee, Sun-Joo; Lee, Dal Nim; Myung, Jae Kyung; Kim, Cheol Hyeon; Jin, Young-Woo; Lee, Seung-Sook; Shim, Sehwan

    2016-01-01

    Radiation-induced lung injury (RILI) due to nuclear or radiological exposure remains difficult to treat because of insufficient clinical data. The goal of this study was to establish an appropriate and efficient minipig model and introduce a thoracic computed tomography (CT)-based method to measure the progression of RILI. Göttingen minipigs were allocated to control and irradiation groups. The most obvious changes in the CT images after irradiation were peribronchial opacification, interlobular septal thickening, and lung volume loss. Hounsfield units (HU) in the irradiation group reached a maximum level at 6 weeks and decreased thereafter, but remained higher than those of the control group. Both lung area and cardiac right lateral shift showed significant changes at 22 weeks post irradiation. The white blood cell (WBC) count, a marker of pneumonitis, increased and reached a maximum at 6 weeks in both peripheral blood and bronchial alveolar lavage fluid. Microscopic findings at 22 weeks post irradiation were characterized by widening of the interlobular septum, with dense fibrosis and an increase in the radiation dose–dependent fibrotic score. Our results also showed that WBC counts and microscopic findings were positively correlated with the three CT parameters. In conclusion, the minipig model can provide useful clinical data regarding RILI caused by the adverse effects of high-dose radiotherapy. Peribronchial opacification, interlobular septal thickening, and lung volume loss are three quantifiable CT parameters that can be used as a simple method for monitoring the progression of RILI. PMID:26712795

  16. Is robotic arm stereotactic body radiation therapy “virtual high dose ratebrachytherapy” for prostate cancer? An analysis of comparative effectiveness using published data [corrected].

    PubMed

    Zaorsky, Nicholas George; Hurwitz, Mark D; Dicker, Adam P; Showalter, Timothy N; Den, Robert B

    2015-05-01

    High-dose rate brachytherapy (HDR-BT) monotherapy and robotic arm (i.e., CyberKnife) stereotactic body radiation therapy (SBRT) are emerging technologies that have become popular treatment options for prostate cancer. Proponents of both HDR-BT monotherapy and robotic arm SBRT claim that these modalities are as efficacious as intensity-modulated radiation therapy in treating prostate cancer. Moreover, proponents of robotic arm SBRT believe it is more effective than HDR-BT monotherapy because SBRT is non-invasive, touting it as 'virtual HDR-BT.' We perform a comparative effective analysis of the two technologies. The tumor control rates and toxicities of HDR-BT monotherapy and robotic arm SBRT are promising. However, at present, it would be inappropriate to state that HDR-BT monotherapy and robotic arm SBRT are as efficacious or effective as other treatment modalities for prostate cancer, which have stronger foundations of evidence. Studies reporting on these technologies have relatively short follow-up time, few patients and are largely retrospective.

  17. Radiation boundary conditions for the numerical solution of the three-dimensional time-dependent Schrödinger equation with a localized interaction.

    PubMed

    Heinen, M; Kull, H-J

    2009-05-01

    Exact radiation boundary conditions on the surface of a sphere are presented for the single-particle time-dependent Schrödinger equation with a localized interaction. With these boundary conditions, numerical computations of spatially unbounded outgoing wave solutions can be restricted to the finite volume of a sphere. The boundary conditions are expressed in terms of the free-particle Green's function for the outside region. The Green's function is analytically calculated by an expansion in spherical harmonics and by the method of Laplace transformation. For each harmonic number a discrete boundary condition between the function values at adjacent radial grid points is obtained. The numerical method is applied to quantum tunneling through a spherically symmetric potential barrier with different angular-momentum quantum numbers l . Calculations for l=0 are compared to exact theoretical results.

  18. High-energy Gamma Rays from the Milky Way: Three-dimensional Spatial Models for the Cosmic-Ray and Radiation Field Densities in the Interstellar Medium

    NASA Astrophysics Data System (ADS)

    Porter, T. A.; Jóhannesson, G.; Moskalenko, I. V.

    2017-09-01

    High-energy γ-rays of interstellar origin are produced by the interaction of cosmic-ray (CR) particles with the diffuse gas and radiation fields in the Galaxy. The main features of this emission are well understood and are reproduced by existing CR propagation models employing 2D galactocentric cylindrically symmetrical geometry. However, the high-quality data from instruments like the Fermi Large Area Telescope reveal significant deviations from the model predictions on few to tens of degrees scales, indicating the need to include the details of the Galactic spiral structure and thus requiring 3D spatial modeling. In this paper, the high-energy interstellar emissions from the Galaxy are calculated using the new release of the GALPROP code employing 3D spatial models for the CR source and interstellar radiation field (ISRF) densities. Three models for the spatial distribution of CR sources are used that are differentiated by their relative proportion of input luminosity attributed to the smooth disk or spiral arms. Two ISRF models are developed based on stellar and dust spatial density distributions taken from the literature that reproduce local near- to far-infrared observations. The interstellar emission models that include arms and bulges for the CR source and ISRF densities provide plausible physical interpretations for features found in the residual maps from high-energy γ-ray data analysis. The 3D models for CR and ISRF densities provide a more realistic basis that can be used for the interpretation of the nonthermal interstellar emissions from the Galaxy.

  19. A three-dimensional chemistry/general circulation model simulation of anthropogenically derived ozone in the troposphere and its radiative climate forcing

    NASA Astrophysics Data System (ADS)

    Roelofs, Geert-Jan; Lelieveld, Jos; van Dorland, Rob

    1997-10-01

    We present results from the tropospheric chemistry/climate European Center Hamburg Model by comparing two simulations that consider a preindustrial and a contemporary emission scenario. Photochemical O3 production from anthropogenically emitted precursors contributes about 30% to the present-day tropospheric O3 content, which is roughly equal to the natural photochemical production. Transports of stratospheric O3 into the troposphere contribute about 40%. As a result of anthropogenic emissions, the O3 maximum over remote northern hemisphere (NH) areas has shifted from winter to spring, when photochemical production of O3 is relatively efficient. Over NH continents the preindustrial seasonal variability is relatively weak whereas a distinct surface O3 summer maximum appears in the contemporary simulation. In the (sub)tropical southern hemisphere (SH), anthropogenic biomass burning emissions cause an increase of O3 mixing ratios in the dry season (September-November). We calculate a relative increase in O3 mixing ratios due to anthropogenic emissions of about 30% in the pristine SH middle and high latitudes to about 100% in the polluted NH boundary layer. The model simulations suggest that the absolute increase of tropospheric O3 maximizes in the middle troposphere. Through convection, upper tropospheric O3 mixing ratios are significantly affected in the tropical regions and, during summer, in the middle and high NH latitudes. Under these conditions the radiative forcing of climate by increasing O3 is relatively large. We calculate a global and annual average radiative forcing by tropospheric O3 perturbations of 0.42 W m-2, i.e., 0.51 W m-2 in the NH and 0.33 W m-2 in the SH.

  20. Contribution of three-dimensional conformal intensity-modulated radiation therapy for women affected by bulky stage II supradiaphragmatic Hodgkin disease.

    PubMed

    Antoni, Delphine; Natarajan-Ame, Shanti; Meyer, Philippe; Niederst, Claudine; Bourahla, Khalil; Noel, Georges

    2013-05-02

    To analyze the outcome and dose distribution of intensity-modulated radiation therapy (IMRT) by helical tomotherapy in women treated for large supradiaphragmatic Hodgkin's disease. A total of 13 patients received adjuvant radiation at a dose of 30 Gy to the initially involved sites with a boost of 6 Gy to those areas suspected of harboring residual disease on the simulation CT scan. With a median follow-up of 23 months, the two-year progression-free survival was 91.6%, and the 2- and 3-year overall survivals were 100%. We did not report any heart or lung acute side effects. The conformity index of PTV (Planning Target Volume) was better for IMRT than for 3D-CRT (p=0.001). For the breasts, lungs, heart, thyroid and esophagus, the volume distributions favored the IMRT plans. For the breasts, the V(20Gy), V(25Gy) and V(30Gy) were 1.5, 2.5 and 3.5 times lower, respectively, for IMRT than for 3D-CRT. For the lung tissues, the V(20Gy) and V(30Gy) were 2 times and 4.5 times lower, respectively, for IMRT than for 3D-CRT. For the heart, the V(20Gy) and V(30Gy) were 1.4 and 2 times lower, respectively, for IMRT than for 3D-CRT. For the esophagus, the V(35Gy) was 1.7 lower for IMRT than for 3D-CRT, and for the thyroid, the V(30Gy) was 1.2 times lower for IMRT. IMRT by helical tomotherapy improved the PTV coverage and dramatically decreased the dose in organs at risk. The treatment was well tolerated, but a longer follow-up is necessary to prove a translation of these dosimetric improvements in the outcome of the patients.

  1. Contribution of three-dimensional conformal intensity-modulated radiation therapy for women affected by bulky stage II supradiaphragmatic Hodgkin disease

    PubMed Central

    2013-01-01

    Purpose To analyze the outcome and dose distribution of intensity-modulated radiation therapy (IMRT) by helical tomotherapy in women treated for large supradiaphragmatic Hodgkin’s disease. Material and methods A total of 13 patients received adjuvant radiation at a dose of 30 Gy to the initially involved sites with a boost of 6 Gy to those areas suspected of harboring residual disease on the simulation CT scan. Results With a median follow-up of 23 months, the two-year progression-free survival was 91.6%, and the 2- and 3-year overall survivals were 100%. We did not report any heart or lung acute side effects. The conformity index of PTV (Planning Target Volume) was better for IMRT than for 3D-CRT (p=0.001). For the breasts, lungs, heart, thyroid and esophagus, the volume distributions favored the IMRT plans. For the breasts, the V20Gy, V25Gy and V30Gy were 1.5, 2.5 and 3.5 times lower, respectively, for IMRT than for 3D-CRT. For the lung tissues, the V20Gy and V30Gy were 2 times and 4.5 times lower, respectively, for IMRT than for 3D-CRT. For the heart, the V20Gy and V30Gy were 1.4 and 2 times lower, respectively, for IMRT than for 3D-CRT. For the esophagus, the V35Gy was 1.7 lower for IMRT than for 3D-CRT, and for the thyroid, the V30Gy was 1.2 times lower for IMRT. Conclusion IMRT by helical tomotherapy improved the PTV coverage and dramatically decreased the dose in organs at risk. The treatment was well tolerated, but a longer follow-up is necessary to prove a translation of these dosimetric improvements in the outcome of the patients. PMID:23638873

  2. Magnetic resonance imaging: an accurate, radiation-free, alternative to computed tomography for the primary imaging and three-dimensional reconstruction of the bony orbit.

    PubMed

    Schmutz, Beat; Rahmel, Benjamin; McNamara, Zeb; Coulthard, Alan; Schuetz, Michael; Lynham, Anthony

    2014-03-01

    To determine the extent to which the accuracy of magnetic resonance imaging (MRI) based virtual 3-dimensional (3D) models of the intact orbit can approach that of the gold standard, computed tomography (CT) based models. The goal was to determine whether MRI is a viable alternative to CT scans in patients with isolated orbital fractures and penetrating eye injuries, pediatric patients, and patients requiring multiple scans in whom radiation exposure is ideally limited. Patients who presented with unilateral orbital fractures to the Royal Brisbane and Women's Hospital from March 2011 to March 2012 were recruited to participate in this cross-sectional study. The primary predictor variable was the imaging technique (MRI vs CT). The outcome measurements were orbital volume (primary outcome) and geometric intraorbital surface deviations (secondary outcome) between the MRI- and CT-based 3D models. Eleven subjects (9 male) were enrolled. The patients' mean age was 30 years. On average, the MRI models underestimated the orbital volume of the CT models by 0.50 ± 0.19 cm(3). The average intraorbital surface deviation between the MRI and CT models was 0.34 ± 0.32 mm, with 78 ± 2.7% of the surface within a tolerance of ±0.5 mm. The volumetric differences of the MRI models are comparable to reported results from CT models. The intraorbital MRI surface deviations are smaller than the accepted tolerance for orbital surgical reconstructions. Therefore, the authors believe that MRI is an accurate radiation-free alternative to CT for the primary imaging and 3D reconstruction of the bony orbit. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  3. Quasicrystalline three-dimensional foams

    NASA Astrophysics Data System (ADS)

    Cox, S. J.; Graner, F.; Mosseri, R.; Sadoc, J.-F.

    2017-03-01

    We present a numerical study of quasiperiodic foams, in which the bubbles are generated as duals of quasiperiodic Frank–Kasper phases. These foams are investigated as potential candidates to the celebrated Kelvin problem for the partition of three-dimensional space with equal volume bubbles and minimal surface area. Interestingly, one of the computed structures falls close to (but still slightly above) the best known Weaire–Phelan periodic candidate. In addition we find a correlation between the normalized bubble surface area and the root mean squared deviation of the number of faces, giving an additional clue to understanding the main geometrical ingredients driving the Kelvin problem.

  4. Three-dimensional light bullets

    NASA Astrophysics Data System (ADS)

    Minardi, S.; Eilenberger, F.; Kartashov, Y. V.; Szameit, A.; Röpke, U.; Kobelke, J.; Schuster, K.; Bartelt, H.; Nolte, S.; Torner, L.; Lederer, F.; Tünnermann, A.; Pertsch, T.

    2012-02-01

    Three dimensional Light Bullets (3D-LBs) are the most symmetric solitary waves, being nonlinear optical wavepackets propagating without diffraction nor dispersion. Since their theoretical prediction, 3D-LB's have constituted a challenge in nonlinear science, due to the impossibility to avoid catastrophic collapse in conventional homogeneous nonlinear media. We have recently observed stable 3D-LBs in media with periodically modulated transverse refractive index profile. We found that higher order linear and nonlinear effects force the 3D-LBs to evolve along their propagation path and eventually decay. The evolution and decay mechanism entails spatiotemporal effects, which under certain conditions, leads to superluminally propagating wavepackets.

  5. Three-dimensional study of the multi-cavity FEL

    SciTech Connect

    Krishnagopal, S.; Kumar, V.

    1995-12-31

    The Multi-Cavity Free-Electron Laser has been proposed earlier, as a new configuration to obtain short, intense pulses of radiation, the key idea being to pre-bunch the electron beam in a number of very short cavities. Those studies were one-dimensional. Here we use three-dimensional simulations to study the viability of this concept when three-dimensional effects are included, particularly with regard to the transverse modes of the optical beam.

  6. Uniform Deterministic Discrete Method for three dimensional systems

    NASA Astrophysics Data System (ADS)

    Li, Ben-Wen; Tao, Wen-Quan; Nie, Yu-Hong

    1997-06-01

    For radiative direct exchange areas in three dimensional system, the Uniform Deterministic Discrete Method (UDDM) was adopted. The spherical surface dividing method for sending area element and the regular icosahedron for sending volume element can meet with the direct exchange area computation of any kind of zone pairs. The numerical examples of direct exchange area in three dimensional system with nonhomogeneous attenuation coefficients indicated that the UDDM can give very high numerical accuracy.

  7. Rapid assessment of high-dose radiation exposures through scoring of cell-fusion-induced premature chromosome condensation and ring chromosomes.

    PubMed

    Lamadrid Boada, A I; Romero Aguilera, I; Terzoudi, G I; González Mesa, J E; Pantelias, G; García, O

    2013-09-18

    Analysis of premature chromosome condensation (PCC) mediated by fusion of G0-lymphocytes with mitotic CHO cells in combination with rapid visualization and quantification of rings (PCC-Rf) is proposed as an alternative technique for dose assessment of radiation-exposed individuals. Isolated lymphocytes or whole blood from six individuals were γ-irradiated with 5, 10, 15 and 20Gy at a dose rate of 0.5Gy/min. Following either 8- or 24-h post-exposure incubation of irradiated samples at 37°C, chromosome spreads were prepared by standard PCC cytogenetic procedures. The protocol for PCC fusion proved to be effective at doses as high as 20Gy, enabling the analysis of ring chromosomes and excess PCC fragments. The ring frequencies remained constant during the 8-24-h repair time; the pooled dose relationship between ring frequency (Y) and dose (D) was linear: Y=(0.088±0.005)×D. During the repair time, excess fragments decreased from 0.91 to 0.59 chromatid pieces per Gy, revealing the importance of information about the exact time of exposure for dose assessment on the basis of fragments. Compared with other cytogenetic assays to estimate radiation dose, the PCC-Rf method has the following benefits: a 48-h culture time is not required, allowing a much faster assessment of dose in comparison with conventional scoring of dicentrics and rings in assays for chemically-induced premature chromosome condensation (PCC-Rch), and it allows the analysis of heavily irradiated lymphocytes that are delayed or never reach mitosis, thus avoiding the problem of saturation at high doses. In conclusion, the use of the PCC fusion assay in conjunction with scoring of rings in G0-lymphocytes offers a suitable alternative for fast dose estimation following accidental exposure to high radiation doses. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. High resolution three-dimensional visualization and characterization of coronary atherosclerosis in vitro by synchrotron radiation x-ray microtomography and highly localized x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Jin, Hua; Ham, Kyungmin; Chan, Julia Y.; Butler, Leslie G.; Kurtz, Richard L.; Thiam, Serigne; Robinson, James W.; Agbaria, Rezik A.; Warner, Isiah M.; Tracy, Richard E.

    2002-12-01

    Human atherosclerotic plaques in both native and bypass arteries have been visualized using microtomography to provide additional information on the nature of coronary artery disease. Plaques contained within arteries removed from three white males aged 51, 55 and 70 are imaged in three-dimensions with monochromatic synchrotron x-ray radiation. Fields of view are 658 × 658 × 517 voxels, with cubic voxels ranging from 12 to 13 µm on a side. X-ray energies range from 11 to 15 keV (bandpass approximately 10 eV). At lower energies, high local absorption tends to generate reconstruction artefacts, while at higher energies the arterial wall is scarcely visible. At all energies, calcifications are clearly visible and differences are observed between plaques in native arteries (lifetime accumulations) versus bypass arteries (plaques developing in the interval between the heart bypass operation and the autopsy). In order to characterize coronary calcification, a micro-focused, 50 µm2, 25 keV x-ray beam was used to acquire powder diffraction data from selected calcifications. Also, large calcifications were removed from the native arteries and imaged with 25 keV x-ray energy. Calcifications are composed of hydroxyapatite crystallites and an amorphous phase. In summary, native calcifications are larger and have a higher fraction of hydroxyapatite than calcifications from the bypass arteries.

  9. Three-dimensional personalized dosimetry for 188Re liver selective internal radiation therapy based on quantitative post-treatment SPECT studies

    NASA Astrophysics Data System (ADS)

    Shcherbinin, S.; Grimes, J.; Bator, A.; Cwikla, J. B.; Celler, A.

    2014-01-01

    We demonstrate that accurate patient-specific distributions of microspheres labeled with 188Re and resulting absorbed doses can be obtained from single-photon emission computed tomography (SPECT) studies performed after 188Re selective internal radiation therapy when accurate correction methods are employed in image reconstruction. Our quantitative image reconstruction algorithm includes corrections for attenuation, resolution degradations and scatter as well as a window-based compensation for contamination. The procedure has been validated using four phantom experiments containing an 18 ml cylindrical source (82-93 MBq of 188Re activity) simulating a liver tumor. In addition, we applied our approach to post-therapy SPECT studies of ten patients with progressive primary or metastatic liver carcinomas. Our quantitative algorithm accurately (within 9%) recovered 188Re activity from four phantom experiments. In addition, for two patients that received three scans, deviations remained consistent between the measured and the reconstructed activities that were determined from studies with differing severity of the dead-time effect. The analysis of absorbed doses for patient studies allowed us to hypothesize that D90 (the minimum dose received by 90% of the tumor volume) may be a reliable metric relating therapy outcomes to the calculated doses. Among several considered metrics, only D90 showed statistically significant correlation with the overall survival.

  10. Long-term Survival and Toxicity in Patients Treated With High-Dose Intensity Modulated Radiation Therapy for Localized Prostate Cancer

    SciTech Connect

    Spratt, Daniel E.; Pei, Xin; Yamada, Josh; Kollmeier, Marisa A.; Cox, Brett; Zelefsky, Michael J.

    2013-03-01

    Purpose: To report long-term survival and toxicity outcomes with the use of high-dose intensity modulated radiation therapy (IMRT) to 86.4 Gy for patients with localized prostate cancer. Methods and Materials: Between August 1997 and December 2008, 1002 patients were treated to a dose of 86.4 Gy using a 5-7 field IMRT technique. Patients were stratified by prognostic risk group based on National Comprehensive Cancer Network risk classification criteria. A total of 587 patients (59%) were treated with neoadjuvant and concurrent androgen deprivation therapy. The median follow-up for the entire cohort was 5.5 years (range, 1-14 years). Results: For low-, intermediate-, and high-risk groups, 7-year biochemical relapse-free survival outcomes were 98.8%, 85.6%, and 67.9%, respectively (P<.001), and distant metastasis-free survival rates were 99.4%, 94.1%, and 82.0% (P<.001), respectively. On multivariate analysis, T stage (P<.001), Gleason score (P<.001), and >50% of initial biopsy positive core (P=.001) were predictive for distant mestastases. No prostate cancer-related deaths were observed in the low-risk group. The 7-year prostate cancer-specific mortality (PCSM) rates, using competing risk analysis for intermediate- and high-risk groups, were 3.3% and 8.1%, respectively (P=.008). On multivariate analysis, Gleason score (P=.004), percentage of biopsy core positivity (P=.003), and T-stage (P=.033) were predictive for PCSM. Actuarial 7-year grade 2 or higher late gastrointestinal and genitourinary toxicities were 4.4% and 21.1%, respectively. Late grade 3 gastrointestinal and genitourinary toxicity was experienced by 7 patients (0.7%) and 22 patients (2.2%), respectively. Of the 427 men with full potency at baseline, 317 men (74%) retained sexual function at time of last follow-up. Conclusions: This study represents the largest cohort of patients treated with high-dose radiation to 86.4 Gy, using IMRT for localized prostate cancer, with the longest follow-up to date

  11. Three-dimensional vortex methods

    SciTech Connect

    Greengard, C.A.

    1984-08-01

    Three-dimensional vortex methods for the computation of incompressible fluid flow are presented from a unified point of view. Reformulations of the filament method and of the method of Beale and Majda show them to be very similar algorithms; in both of them, the vorticity is evaluated by a discretization of the spatial derivative of the flow map. The fact that the filament method, the one which is most often used in practice, can be formulated as a version of the Beale and Majda algorithm in a curved coordinate system is used to give a convergence theorem for the filament method. The method of Anderson is also discussed, in which vorticity is evaluated by the exact differentiation of the approximate velocity field. It is shown that, in the inviscid version of this algorithm, each approximate vector of vorticity remains tangent to a material curve moving with the computed flow, with magnitude proportional to the stretching of this vortex line. This remains true even when time discretization is taken into account. It is explained that the expanding core vortex method converges to a system of equations different from the Navier-Stokes equations. Computations with the filament method of the inviscid interaction of two vortex rings are reported, both with single filaments in each ring and with a fully three-dimensional discretization of vorticity. The dependence on parameters is discussed, and convergence of the computed solutions is observed. 36 references, 4 figures.

  12. Dosimetric comparison study between intensity modulated radiation therapy and three-dimensional conformal proton therapy for pelvic bone marrow sparing in the treatment of cervical cancer.

    PubMed

    Song, William Y; Huh, Soon N; Liang, Yun; White, Greg; Nichols, R Charles; Watkins, W Tyler; Mundt, Arno J; Mell, Loren K

    2010-08-15

    The objective was to compare intensity-modulated radiation therapy (IMRT) with 3D conformal proton therapy (3DCPT) in the treatment of cervical cancer. In particular, each technique's ability to spare pelvic bone marrow (PBM) was of primary interest in this study. A total of six cervical cancer patients (3 postoperative and 3 intact) were planned and analyzed. All plans had uniform 1.0 cm CTV-PTV margin and satisfied the 95% PTV with 100% isodose (prescription dose = 45 Gy) coverage. Dose-volume histograms (DVH) were analyzed for comparison. The overall PTV and PBM volumes were 1035.9 ± 192.2 cc and 1151.4 ± 198.3 cc, respectively. In terms of PTV dose conformity index (DCI) and dose homogeneity index (DHI), 3DCPT was slightly superior to IMRT with 1.00 ± 0.001, 1.01 ± 0.02, and 1.10 ± 0.02, 1.13 ± 0.01, respectively. In addition, 3DCPT demonstrated superiority in reducing lower doses (i.e., V30 or less) to PBM, small bowel and bladder. Particularly in PBM, average V10 and V20 reductions of 10.8% and 7.4% (p = 0.001 and 0.04), respectively, were observed. However, in the higher dose range, IMRT provided better sparing (> V30). For example, in small bowel and PBM, average reductions in V45 of 4.9% and 10.0% (p = 0.048 and 0.008), respectively, were observed. Due to its physical characteristics such as low entrance dose, spread-out Bragg peak and finite particle range of protons, 3DCPT illustrated superior target coverage uniformity and sparing of the lower doses in PBM and other organs. Further studies are, however, needed to fully exploit the benefits of protons for general use in cervical cancer.

  13. Image-guided high-dose-rate brachytherapy in inoperable endometrial cancer

    PubMed Central

    Petsuksiri, J; Chansilpa, Y; Hoskin, P J

    2014-01-01

    Inoperable endometrial cancer may be treated with curative aim using radical radiotherapy alone. The radiation techniques are external beam radiotherapy (EBRT) alone, EBRT plus brachytherapy and brachytherapy alone. Recently, high-dose-rate brachytherapy has been used instead of low-dose-rate brachytherapy. Image-guided brachytherapy enables sufficient coverage of tumour and reduction of dose to the organs at risk, thus increasing the therapeutic ratio of treatment. Local control rates with three-dimensional brachytherapy appear better than with conventional techniques (about 90–100% and 70–90%, respectively). PMID:24807067

  14. Mechanisms of action for an anti-radiation vaccine in reducing the biological impact of high dose and dose-rate, low-linear energy transfer radiation exposure.

    PubMed

    Maliev, V; Popov, D; Casey, R C; Jones, J A

    2007-01-01

    The development of an anti-radiation vaccine could be very useful in reducing acute radiation syndromes. Existing principles for the treatment of acute radiation syndromes are based on the amelioration of progressive pathophysiological changes, using the concept of replacement therapy. Active immunization by small quantities of the essential radiation-induced systemic toxins of what we call the Specific Radiation Determinant (SRD) before irradiation increased duration of life among animals that were irradiated by lethal or sub-lethal doses of gamma-radiation. The SRD toxins possess antigenic properties that are specific to different forms of acute radiation sickness. Intramuscular injection of larger quantities of the SRD toxins induce signs and symptoms in irradiated naive animals similar to those observed in acute radiation syndromes, including death. Providing passive immunization, at variable periods of time following radiation, with preparations of immune-globulins directed at the SRD molecules, can confer some protection in the development of clinical sequelae in irradiated animals. Improved survival rates and times were observed in animals that received lower, sublethal doses of the same SRDs prior to irradiation. Therefore, active immunization can be induced by SRD molecules as a prophylaxis. The protective effects of the immunization begin to manifest 15-35 days after an injection of a biologically active SDR preparation. The SRD molecules are a group of radiation toxins with antigenic properties that correlate specifically with different forms of radiation disease. The SRD molecules are composed of glycoproteins and lipoproteins that accumulate in the lymphatic system of mammals in the first hours after irradiation, and preliminary analysis suggests that they may originate from cellular membrane components. The molecular weight of the SRD group ranges from 200-250 kDa. The SRD molecules were isolated from the lymphatic systems of laboratory animals that

  15. Whole brain radiation dose reduction for primary central nervous system lymphoma patients who achieved partial response after high-dose methotrexate based chemotherapy.

    PubMed

    Park, Jun Su; Lim, Do Hoon; Ahn, Yong Chan; Park, Won; Kim, Seok Jin; Kim, Won Seog; Kim, Kihyun

    2017-08-30

    The whole brain radiotherapy (WBRT) dose for primary central nervous system lymphoma (PCNSL) patients who achieved complete response after induction chemotherapy was recently reduced to 23.4 Gy, but the optimal radiation dose for patients who achieved partial response (PR) is controversial. The aim of this study was to investigate the feasibility of reduced-dose WBRT for patients who achieved PR. We retrospectively reviewed the medical records of PCNSL patients who were treated with high-dose methotrexate based chemotherapy. We compared treatment outcomes between the patients who received WBRT at either 36 Gy or 45 Gy. The overall survival (OS) and intracranial progression-free survival (IC-PFS) was 66.3% and 42.6% at 5 years, respectively. There was no significant difference in treatment outcomes between the patients who received 36 Gy and 45 Gy, especially among patients who achieved PR. Three-year OS was 100% and 83.3% for 36 Gy and 45 Gy group, respectively (P = 0.313). Three-year IC-PFS was 60.0% and 66.7% for 36 Gy and 45 Gy group, respectively (P = 0.916). Findings of our study might provide a possibility for dose-reduction in patients achieving PR to induction chemotherapy, which may in turn reduce delayed neurologic sequelae. However, the number of patients included in this study was too small to lead to a concrete conclusion, thus further study is needed.

  16. Three-dimensional aromatic networks.

    PubMed

    Toyota, Shinji; Iwanaga, Tetsuo

    2014-01-01

    Three-dimensional (3D) networks consisting of aromatic units and linkers are reviewed from various aspects. To understand principles for the construction of such compounds, we generalize the roles of building units, the synthetic approaches, and the classification of networks. As fundamental compounds, cyclophanes with large aromatic units and aromatic macrocycles with linear acetylene linkers are highlighted in terms of transannular interactions between aromatic units, conformational preference, and resolution of chiral derivatives. Polycyclic cage compounds are constructed from building units by linkages via covalent bonds, metal-coordination bonds, or hydrogen bonds. Large cage networks often include a wide range of guest species in their cavity to afford novel inclusion compounds. Topological isomers consisting of two or more macrocycles are formed by cyclization of preorganized species. Some complicated topological networks are constructed by self-assembly of simple building units.

  17. Three-dimensional display technologies.

    PubMed

    Geng, Jason

    2013-01-01

    The physical world around us is three-dimensional (3D), yet traditional display devices can show only two-dimensional (2D) flat images that lack depth (i.e., the third dimension) information. This fundamental restriction greatly limits our ability to perceive and to understand the complexity of real-world objects. Nearly 50% of the capability of the human brain is devoted to processing visual information [Human Anatomy & Physiology (Pearson, 2012)]. Flat images and 2D displays do not harness the brain's power effectively. With rapid advances in the electronics, optics, laser, and photonics fields, true 3D display technologies are making their way into the marketplace. 3D movies, 3D TV, 3D mobile devices, and 3D games have increasingly demanded true 3D display with no eyeglasses (autostereoscopic). Therefore, it would be very beneficial to readers of this journal to have a systematic review of state-of-the-art 3D display technologies.

  18. Three-dimensional coil inductor

    DOEpatents

    Bernhardt, Anthony F.; Malba, Vincent

    2002-01-01

    A three-dimensional coil inductor is disclosed. The inductor includes a substrate; a set of lower electrically conductive traces positioned on the substrate; a core placed over the lower traces; a set of side electrically conductive traces laid on the core and the lower traces; and a set of upper electrically conductive traces attached to the side traces so as to form the inductor. Fabrication of the inductor includes the steps of forming a set of lower traces on a substrate; positioning a core over the lower traces; forming a set of side traces on the core; connecting the side traces to the lower traces; forming a set of upper traces on the core; and connecting the upper traces to the side traces so as to form a coil structure.

  19. Three-dimensional vortex methods

    NASA Astrophysics Data System (ADS)

    Greengard, C. A.

    1984-08-01

    Reformulations of the filament method and of the method of Beale and Majda show them to be very similar algorithms. The method of Anderson in which vorticity is evaluated by the exact differentiation of the approximate velocity field is discussed. It is shown that, in the inviscid version of this algorithm, each approximate vector of vorticity remains tangent to a material curve moving with the computed flow, with magnitude proportional to the stretching of this vortex line. It is explained that the expanding core vortex method converges to a system of equations different from the Navier-Stokes equations. Computations with the filament method of the inviscid interaction of two vortex rings are reported, both with single filaments in each ring and with a fully three-dimensional discretization of vorticity. The dependence on parameters is discussed, and convergence of the computed solutions is observed.

  20. CT computer-optimized high-dose-rate brachytherapy with surface applicator technique for scar boost radiation after breast reconstruction surgery.

    PubMed

    Stewart, Alexandra J; O'Farrell, Desmond A; Bellon, Jennifer R; Hansen, Jorgen L; Duggan, Catherine; Czerminska, Maria A; Cormack, Robert A; Devlin, Phillip M

    2005-01-01

    Immediate breast reconstruction has become increasingly prevalent after mastectomy for breast cancer. Postoperative scar boost radiation for the reconstructed breast presents many planning challenges due to the shape, size, and curvature of the scar. High-dose-rate (HDR) surface applicator brachytherapy is a novel and effective method of delivering scar boost radiation. Two cases, one with a saline implant and one with a transverse rectus abdominis musculocutaneous flap reconstruction, illustrate the method and advantages of HDR optimization of surface applicators. For 2 patients a mold of the breast was made with Aquaplast sheets. A reproducible system was used for arm positioning. Skin fiducials, including tattoos from external beam planning, were matched to fiducials on the mold. HDR catheters were sited on the mold at 1cm intervals, with the central catheter situated along the scar. Topographically, both scars demonstrated extreme curvature in both craniocaudal and mediolateral directions. A CT computer-optimized HDR plan was developed, with the reference dose prescribed at the skin surface. The dosimetry was compared to single-field and matched-field electron plans. This surface applicator technique provided a uniform skin dose of 100% to the entire clinical target volume (CTV) without hot spots in both patients. The patient position and surface applicator setup were consistently reproducible. The patients tolerated the treatment well with minimal skin erythema. In the single-field electron plan, skin dose was decreased to 50% at the periphery of the scar. Matching fields addressed this depth dose decrement, but resulted in large localized hot spots of more than 200% centrally in each field. CT computer-optimized HDR surface applicator brachytherapy provided a reproducible homogeneous method of treating highly curved scars on the reconstructed breast. Electron beam treatment would result in longer and more complex treatments yet still provide a less

  1. Early observed transient prostate-specific antigen elevations on a pilot study of external beam radiation therapy and fractionated MRI guided High Dose Rate brachytherapy boost

    PubMed Central

    Singh, Anurag K; Guion, Peter; Susil, Robert C; Citrin, Deborah E; Ning, Holly; Miller, Robert W; Ullman, Karen; Smith, Sharon; Crouse, Nancy Sears; Godette, Denise J; Stall, Bronwyn R; Coleman, C Norman; Camphausen, Kevin; Ménard, Cynthia

    2006-01-01

    Purpose To report early observation of transient PSA elevations on this pilot study of external beam radiation therapy and magnetic resonance imaging (MRI) guided high dose rate (HDR) brachytherapy boost. Materials and methods Eleven patients with intermediate-risk and high-risk localized prostate cancer received MRI guided HDR brachytherapy (10.5 Gy each fraction) before and after a course of external beam radiotherapy (46 Gy). Two patients continued on hormones during follow-up and were censored for this analysis. Four patients discontinued hormone therapy after RT. Five patients did not receive hormones. PSA bounce is defined as a rise in PSA values with a subsequent fall below the nadir value or to below 20% of the maximum PSA level. Six previously published definitions of biochemical failure to distinguish true failure from were tested: definition 1, rise >0.2 ng/mL; definition 2, rise >0.4 ng/mL; definition 3, rise >35% of previous value; definition 4, ASTRO defined guidelines, definition 5 nadir + 2 ng/ml, and definition 6, nadir + 3 ng/ml. Results Median follow-up was 24 months (range 18–36 mo). During follow-up, the incidence of transient PSA elevation was: 55% for definition 1, 44% for definition 2, 55% for definition 3, 33% for definition 4, 11% for definition 5, and 11% for definition 6. Conclusion We observed a substantial incidence of transient elevations in PSA following combined external beam radiation and HDR brachytherapy for prostate cancer. Such elevations seem to be self-limited and should not trigger initiation of salvage therapies. No definition of failure was completely predictive. PMID:16914054

  2. A Contralateral Esophagus-Sparing Technique to Limit Severe Esophagitis Associated With Concurrent High-Dose Radiation and Chemotherapy in Patients With Thoracic Malignancies

    SciTech Connect

    Al-Halabi, Hani; Paetzold, Peter; Sharp, Gregory C.; Olsen, Christine; Willers, Henning

    2015-07-15

    Purpose: Severe (Radiation Therapy Oncology Group [RTOG] grade 3 or greater) esophagitis generally occurs in 15% to 25% of non–small cell lung cancer (NSCLC) patients undergoing concurrent chemotherapy and radiation therapy (CCRT), which may result in treatment breaks that compromise local tumor control and pose a barrier to dose escalation. Here, we report a novel contralateral esophagus-sparing technique (CEST) that uses intensity modulated radiation therapy (IMRT) to reduce the incidence of severe esophagitis. Methods and Materials: We reviewed consecutive patients with thoracic malignancies undergoing curative CCRT in whom CEST was used. The esophageal wall contralateral (CE) to the tumor was contoured as an avoidance structure, and IMRT was used to guide a rapid dose falloff gradient beyond the target volume in close proximity to the esophagus. Esophagitis was recorded based on the RTOG acute toxicity grading system. Results: We identified 20 consecutive patients treated with CCRT of at least 63 Gy in whom there was gross tumor within 1 cm of the esophagus. The median radiation dose was 70.2 Gy (range, 63-72.15 Gy). In all patients, ≥99% of the planning and internal target volumes was covered by ≥90% and 100% of prescription dose, respectively. Strikingly, no patient experienced grade ≥3 esophagitis (95% confidence limits, 0%-16%) despite the high total doses delivered. The median maximum dose, V45, and V55 of the CE were 60.7 Gy, 2.1 cc, and 0.4 cc, respectively, indicating effective esophagus cross-section sparing by CEST. Conclusion: We report a simple yet effective method to avoid exposing the entire esophagus cross-section to high doses. By using proposed CE dose constraints of V45 <2.5 cc and V55 <0.5 cc, CEST may improve the esophagus toxicity profile in thoracic cancer patients receiving CCRT even at doses above the standard 60- to 63-Gy levels. Prospective testing of CEST is warranted.

  3. Simulating Three Dimensional Radiation Belt Dynamics

    NASA Astrophysics Data System (ADS)

    Perry, K. L.; Eccles, A. A.; Elkington, S. R.; Hudson, M. K.

    2001-12-01

    The model by Elkington et al. [1999], which uses a compressed dipole and a time-varying electric field in two dimensions, is extended to three dimensions by specifying a poloidal mode ULF wave with a single vector potential component described by Li et al. [1993] resulting in Eφ , Br and B//. The toroidal mode can similarly be specified by a single vector potential component yielding Er and Bφ . These vector potentials assume a Gaussian radial amplitude profile, a simple sine or cosine for the parallel mode structure and a time varying exponential depending on the mode number and angle in the azimuthal direction. Elkington, S. R., M. K. Hudson, and A. A. Chan, Acceleration of relativistic electrons via drift-resonant interaction with toroidal-mode Pc-5 ULF oscillations,Geophys. Res. Lett., 26, 3273, 1999. Li, X., M. K. Hudson, A. A. Chan, and I. Roth, Loss of ring current O+ ions due to interaction with Pc-5 waves, J. Geophys. Res., 98, 215, 1993.

  4. Phase II Study of Accelerated High-Dose Radiotherapy With Concurrent Chemotherapy for Patients With Limited Small-Cell Lung Cancer: Radiation Therapy Oncology Group Protocol 0239

    SciTech Connect

    Komaki, Ritsuko; Paulus, Rebecca; Ettinger, David S.; Videtic, Gregory M.M.; Bradley, Jeffrey D.; Glisson, Bonnie S.; Sause, William T.; Curran, Walter J.; Choy, Hak

    2012-07-15

    Purpose: To investigate whether high-dose thoracic radiation given twice daily during cisplatin-etoposide chemotherapy for limited small-cell lung cancer (LSCLC) improves survival, acute esophagitis, and local control rates relative to findings from Intergroup trial 0096 (47%, 27%, and 64%). Patients and Methods: Patients were accrued over a 3-year period from 22 US and Canadian institutions. Patients with LSCLC and good performance status were given thoracic radiation to 61.2 Gy over 5 weeks (daily 1.8-Gy fractions on days 1-22, then twice-daily 1.8-Gy fractions on days 23-33). Cisplatin (60 mg/m{sup 2} IV) was given on day 1 and etoposide (120 mg/m{sup 2} IV) on days 1-3 and days 22-24, followed by 2 cycles of cisplatin plus etoposide alone. Patients who achieved complete response were offered prophylactic cranial irradiation. Endpoints included overall and progression-free survival; severe esophagitis (Common Toxicity Criteria v 2.0) and treatment-related fatalities; response (Response Evaluation Criteria in Solid Tumors); and local control. Results: Seventy-two patients were accrued from June 2003 through May 2006; 71 were evaluable (median age 63 years; 52% female; 58% Zubrod 0). Median survival time was 19 months; at 2 years, the overall survival rate was 36.6% (95% confidence interval [CI] 25.6%-47.7%), and progression-free survival 19.7% (95% CI 11.4%-29.6%). Thirteen patients (18%) experienced severe acute esophagitis, and 2 (3%) died of treatment-related causes; 41% achieved complete response, 39% partial response, 10% stable disease, and 6% progressive disease. The local control rate was 73%. Forty-three patients (61%) received prophylactic cranial irradiation. Conclusions: The overall survival rate did not reach the projected goal; however, rates of esophagitis were lower, and local control higher, than projected. This treatment strategy is now one of three arms of a prospective trial of chemoradiation for LSCLC (Radiation Therapy Oncology Group 0538

  5. Impact of Dose to the Bladder Trigone on Long-Term Urinary Function After High-Dose Intensity Modulated Radiation Therapy for Localized Prostate Cancer

    SciTech Connect

    Ghadjar, Pirus; Zelefsky, Michael J.; Spratt, Daniel E.; Munck af Rosenschöld, Per; Oh, Jung Hun; Hunt, Margie; Kollmeier, Marisa; Happersett, Laura; Yorke, Ellen; Deasy, Joseph O.; Jackson, Andrew

    2014-02-01

    Purpose: To determine the potential association between genitourinary (GU) toxicity and planning dose–volume parameters for GU pelvic structures after high-dose intensity modulated radiation therapy in localized prostate cancer patients. Methods and Materials: A total of 268 patients who underwent intensity modulated radiation therapy to a prescribed dose of 86.4 Gy in 48 fractions during June 2004-December 2008 were evaluated with the International Prostate Symptom Score (IPSS) questionnaire. Dose–volume histograms of the whole bladder, bladder wall, urethra, and bladder trigone were analyzed. The primary endpoint for GU toxicity was an IPSS sum increase ≥10 points over baseline. Univariate and multivariate analyses were done by the Kaplan-Meier method and Cox proportional hazard models, respectively. Results: Median follow-up was 5 years (range, 3-7.7 years). Thirty-nine patients experienced an IPSS sum increase ≥10 during follow-up; 84% remained event free at 5 years. After univariate analysis, lower baseline IPSS sum (P=.006), the V90 of the trigone (P=.006), and the maximal dose to the trigone (P=.003) were significantly associated with an IPSS sum increase ≥10. After multivariate analysis, lower baseline IPSS sum (P=.009) and increased maximal dose to the trigone (P=.005) remained significantly associated. Seventy-two patients had both a lower baseline IPSS sum and a higher maximal dose to the trigone and were defined as high risk, and 68 patients had both a higher baseline IPSS sum and a lower maximal dose to the trigone and were defined as low risk for development of an IPSS sum increase ≥10. Twenty-one of 72 high-risk patients (29%) and 5 of 68 low-risk patients (7%) experienced an IPSS sum increase ≥10 (P=.001; odds ratio 5.19). Conclusions: The application of hot spots to the bladder trigone was significantly associated with relevant changes in IPSS during follow-up. Reduction of radiation dose to the lower bladder and specifically the

  6. A Novel Form of Breast Intraoperative Radiation Therapy With CT-Guided High-Dose-Rate Brachytherapy: Results of a Prospective Phase 1 Clinical Trial.

    PubMed

    Showalter, Shayna L; Petroni, Gina; Trifiletti, Daniel M; Libby, Bruce; Schroen, Anneke T; Brenin, David R; Dalal, Parchayi; Smolkin, Mark; Reardon, Kelli A; Showalter, Timothy N

    2016-09-01

    Existing intraoperative radiation therapy (IORT) techniques are criticized for the lack of image guided treatment planning and energy deposition with, at times, poor resultant dosimetry and low radiation dose. We pioneered a novel method of IORT that incorporates customized, computed tomography (CT)-based treatment planning and high-dose-rate (HDR) brachytherapy to overcome these drawbacks: CT-HDR-IORT. A phase 1 study was conducted to demonstrate the feasibility and safety of CT-HDR-IORT. Eligibility criteria included age ≥50 years, invasive or in situ breast cancer, tumor size <3 cm, and N0 disease. Patients were eligible before or within 30 days of breast-conserving surgery (BCS). BCS was performed, and a multilumen balloon catheter was placed. CT images were obtained, a customized HDR brachytherapy plan was created, and a dose of 12.5 Gy was delivered to 1-cm depth from the balloon surface. The catheter was removed, and the skin was closed. The primary endpoints were feasibility and acute toxicity. Feasibility was defined as IORT treatment interval (time from CT acquisition until IORT completion) ≤90 minutes. The secondary endpoints included dosimetry, cosmetic outcome, quality of life, and late toxicity. Twenty-eight patients were enrolled. The 6-month follow-up assessments were completed by 93% of enrollees. The median IORT treatment interval was 67.2 minutes (range, 50-108 minutes). The treatment met feasibility criteria in 26 women (93%). The dosimetric goals were met in 22 patients (79%). There were no Radiation Therapy Oncology Group grade 3+ toxicities; 6 patients (21%) experienced grade 2 events. Most patients (93%) had good/excellent cosmetic outcomes at the last follow-up visit. CT-HDR-IORT is feasible and safe. This promising approach for a conformal, image-based, higher-dose breast IORT is being evaluated in a phase 2 trial. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Effective treatment of stage I uterine papillary serous carcinoma with high dose-rate vaginal apex radiation (192Ir) and chemotherapy.

    PubMed

    Turner, B C; Knisely, J P; Kacinski, B M; Haffty, B G; Gumbs, A A; Roberts, K B; Frank, A H; Peschel, R E; Rutherford, T J; Edraki, B; Kohorn, E I; Chambers, S K; Schwartz, P E; Wilson, L D

    1998-01-01

    Uterine papillary serous carcinoma (UPSC) is a morphologically distinct variant of endometrial carcinoma that is associated with a poor prognosis, high recurrence rate, frequent clinical understaging, and poor response to salvage treatment. We retrospectively analyzed local control, actuarial overall survival (OS), actuarial disease-free survival (DFS), salvage rate, and complications for patients with Federation International of Gynecology and Obstetrics (FIGO) (1988) Stage I UPSC. This retrospective analysis describes 38 patients with FIGO Stage I UPSC who were treated with the combinations of radiation therapy, chemotherapy, total abdominal hysterectomy, and bilateral salpingo-oophorectomy (TAH/BSO), with or without a surgical staging procedure. Twenty of 38 patients were treated with a combination of low dose-rate (LDR) uterine/vaginal brachytherapy using 226Ra or 137Cs and conventional whole-abdomen radiation therapy (WART) or whole-pelvic radiation therapy (WPRT). Of 20 patients (10%) in this treatment group, 2 received cisplatin chemotherapy. Eighteen patients were treated with high dose-rate (HDR) vaginal apex brachytherapy using 192Ir with an afterloading device and cisplatin, doxorubicin, and cyclophosphamide (CAP) chemotherapy (5 of 18 patients). Only 6 of 20 UPSC patients treated with combination LDR uterine/vaginal brachytherapy and conventional external beam radiotherapy underwent complete surgical staging, consisting of TAH/BSO, pelvic/para-aortic lymph node sampling, omentectomy, and peritoneal fluid analysis, compared to 15 of 18 patients treated with HDR vaginal apex brachytherapy. The 5-year actuarial OS for patients with complete surgical staging and adjuvant radiation/chemotherapy treatment was 100% vs. 61% for patients without complete staging (p = 0.002). The 5-year actuarial OS for all Stage I UPSC patients treated with postoperative HDR vaginal apex brachytherapy and systemic chemotherapy was 94% (18 patients). The 5-year actuarial OS for

  8. Three-dimensional colloidal lithography.

    PubMed

    Nagai, Hironori; Poteet, Austen; Zhang, Xu A; Chang, Chih-Hao

    2017-03-24

    Light interactions with colloidal particles can generate a variety of complex three-dimensional (3D) intensity patterns, which can be utilized for nanolithography. The study of particle-light interactions can add more types of intensity patterns by manipulating key factors. Here we investigate a novel 3D nanolithography technique using colloidal particles under two-beam coherent illuminations. The fabricated 3D nanostructures are hollow, nested within periodic structures, and possess multiple chamber geometry. The effects of incident angles and particle size on the fabricated nanostructures were examined. The relative phase shift between particle position and interference pattern is identified as another significant parameter influencing the resultant nanostructures. A numerical model has been developed to show the evolution of nanostructure geometry with phase shifts, and experimental studies confirm the simulation results. Through the introduction of single colloidal particles, the fabrication capability of Lloyd's mirror interference can now be extended to fabrication of 3D nanostructure with complex shell geometry. The fabricated hollow nanostructures with grating background could find potential applications in the area of photonics, drug delivery, and nanofluidics.

  9. Three-dimensional colloidal lithography

    NASA Astrophysics Data System (ADS)

    Nagai, Hironori; Poteet, Austen; Zhang, Xu A.; Chang, Chih-Hao

    2017-03-01

    Light interactions with colloidal particles can generate a variety of complex three-dimensional (3D) intensity patterns, which can be utilized for nanolithography. The study of particle-light interactions can add more types of intensity patterns by manipulating key factors. Here we investigate a novel 3D nanolithography technique using colloidal particles under two-beam coherent illuminations. The fabricated 3D nanostructures are hollow, nested within periodic structures, and possess multiple chamber geometry. The effects of incident angles and particle size on the fabricated nanostructures were examined. The relative phase shift between particle position and interference pattern is identified as another significant parameter influencing the resultant nanostructures. A numerical model has been developed to show the evolution of nanostructure geometry with phase shifts, and experimental studies confirm the simulation results. Through the introduction of single colloidal particles, the fabrication capability of Lloyd’s mirror interference can now be extended to fabrication of 3D nanostructure with complex shell geometry. The fabricated hollow nanostructures with grating background could find potential applications in the area of photonics, drug delivery, and nanofluidics.

  10. Three-dimensional display technologies

    PubMed Central

    Geng, Jason

    2014-01-01

    The physical world around us is three-dimensional (3D), yet traditional display devices can show only two-dimensional (2D) flat images that lack depth (i.e., the third dimension) information. This fundamental restriction greatly limits our ability to perceive and to understand the complexity of real-world objects. Nearly 50% of the capability of the human brain is devoted to processing visual information [Human Anatomy & Physiology (Pearson, 2012)]. Flat images and 2D displays do not harness the brain’s power effectively. With rapid advances in the electronics, optics, laser, and photonics fields, true 3D display technologies are making their way into the marketplace. 3D movies, 3D TV, 3D mobile devices, and 3D games have increasingly demanded true 3D display with no eyeglasses (autostereoscopic). Therefore, it would be very beneficial to readers of this journal to have a systematic review of state-of-the-art 3D display technologies. PMID:25530827

  11. Three-dimensional laser microvision.

    PubMed

    Shimotahira, H; Iizuka, K; Chu, S C; Wah, C; Costen, F; Yoshikuni, Y

    2001-04-10

    A three-dimensional (3-D) optical imaging system offering high resolution in all three dimensions, requiring minimum manipulation and capable of real-time operation, is presented. The system derives its capabilities from use of the superstructure grating laser source in the implementation of a laser step frequency radar for depth information acquisition. A synthetic aperture radar technique was also used to further enhance its lateral resolution as well as extend the depth of focus. High-speed operation was made possible by a dual computer system consisting of a host and a remote microcomputer supported by a dual-channel Small Computer System Interface parallel data transfer system. The system is capable of operating near real time. The 3-D display of a tunneling diode, a microwave integrated circuit, and a see-through image taken by the system operating near real time are included. The depth resolution is 40 mum; lateral resolution with a synthetic aperture approach is a fraction of a micrometer and that without it is approximately 10 mum.

  12. Three-Dimensional Laser Microvision

    NASA Astrophysics Data System (ADS)

    Shimotahira, Hiroshi; Iizuka, Keigo; Chu, Sun-Chun; Wah, Christopher; Costen, Furnie; Yoshikuni, Yuzo

    2001-04-01

    A three-dimensional (3-D) optical imaging system offering high resolution in all three dimensions, requiring minimum manipulation and capable of real-time operation, is presented. The system derives its capabilities from use of the superstructure grating laser source in the implementation of a laser step frequency radar for depth information acquisition. A synthetic aperture radar technique was also used to further enhance its lateral resolution as well as extend the depth of focus. High-speed operation was made possible by a dual computer system consisting of a host and a remote microcomputer supported by a dual-channel Small Computer System Interface parallel data transfer system. The system is capable of operating near real time. The 3-D display of a tunneling diode, a microwave integrated circuit, and a see-through image taken by the system operating near real time are included. The depth resolution is 40 m; lateral resolution with a synthetic aperture approach is a fraction of a micrometer and that without it is approximately 10 m.

  13. Three dimensional magnetic abacus memory

    PubMed Central

    Zhang, ShiLei; Zhang, JingYan; Baker, Alexander A.; Wang, ShouGuo; Yu, GuangHua; Hesjedal, Thorsten

    2014-01-01

    Stacking nonvolatile memory cells into a three-dimensional matrix represents a powerful solution for the future of magnetic memory. However, it is technologically challenging to access the data in the storage medium if large numbers of bits are stacked on top of each other. Here we introduce a new type of multilevel, nonvolatile magnetic memory concept, the magnetic abacus. Instead of storing information in individual magnetic layers, thereby having to read out each magnetic layer separately, the magnetic abacus adopts a new encoding scheme. It is inspired by the idea of second quantisation, dealing with the memory state of the entire stack simultaneously. Direct read operations are implemented by measuring the artificially engineered ‘quantised' Hall voltage, each representing a count of the spin-up and spin-down layers in the stack. This new memory system further allows for both flexible scaling of the system and fast communication among cells. The magnetic abacus provides a promising approach for future nonvolatile 3D magnetic random access memory. PMID:25146338

  14. High-Dose and Extended-Field Intensity Modulated Radiation Therapy for Early-Stage NK/T-Cell Lymphoma of Waldeyer's Ring: Dosimetric Analysis and Clinical Outcome

    SciTech Connect

    Bi, Xi-Wen; Li, Ye-Xiong Fang, Hui; Jin, Jing; Wang, Wei-Hu; Wang, Shu-Lian; Liu, Yue-Ping; Song, Yong-Wen; Ren, Hua; Dai, Jian-Rong

    2013-12-01

    Purpose: To assess the dosimetric benefit, treatment outcome, and toxicity of high-dose and extended-field intensity modulated radiation therapy (IMRT) in patients with early-stage NK/T-cell lymphoma of Waldeyer's ring (WR-NKTCL). Methods and Materials: Thirty patients with early-stage WR-NKTCL who received extended-field IMRT were retrospectively reviewed. The prescribed dose was 50 Gy to the primary involved regions and positive cervical lymph nodes (planning target volume requiring radical irradiation [PTV{sub 50}]) and 40 Gy to the negative cervical nodes (PTV{sub 40}). Dosimetric parameters for the target volume and critical normal structures were evaluated. Locoregional control (LRC), overall survival (OS), and progression-free survival (PFS) were calculated using the Kaplan-Meier method. Results: The median mean doses to the PTV{sub 50} and PTV{sub 40} were 53.2 Gy and 43.0 Gy, respectively. Only 1.4% of the PTV{sub 50} and 0.9% of the PTV{sub 40} received less than 95% of the prescribed dose, indicating excellent target coverage. The average mean doses to the left and right parotid glands were 27.7 and 28.4 Gy, respectively. The 2-year OS, PFS, and LRC rates were 71.2%, 57.4%, and 87.8%. Most acute toxicities were grade 1 to 2, except for grade ≥3 dysphagia and mucositis. The most common late toxicity was grade 1-2 xerostomia, and no patient developed any ≥grade 3 late toxicities. A correlation between the mean dose to the parotid glands and the degree of late xerostomia was observed. Conclusions: IMRT achieves excellent target coverage and dose conformity, as well as favorable survival and locoregional control rates with acceptable toxicities in patients with WR-NKTCL.

  15. A dosimetric analysis of intensity-modulated radiation therapy (IMRT) as an alternative to adjuvant high-dose-rate (HDR) brachytherapy in early endometrial cancer patients

    SciTech Connect

    Aydogan, Bulent . E-mail: baydogan@radonc.uchicago.edu; Mundt, Arno J.; Smith, Brett D.; Mell, Loren K.; Wang, Steve; Sutton, Harold; Roeske, John C.

    2006-05-01

    Purpose: To evaluate the role of intensity-modulated radiation treatment (IMRT) as an alternative to high-dose-rate (HDR) brachytherapy in the treatment of the vagina in postoperative early endometrial cancer patients after surgery. Methods and Materials: Planning computed tomography (CT) scans of 10 patients previously treated with HDR were used in this study. In all cases, a dose of 700 cGy/fraction was prescribed at a distance of 0.5 cm from the cylinder surface. The same CT scans were then used in IMRT planning. In this paradigm, the vaginal cylinder represents a component of a hypothetical immobilization system that would be indexed to the linac treatment table. Results: Our study showed that IMRT provided relatively lower rectal doses than HDR when treatment was prescribed at a distance of 0.5 cm away from the cylinder surface. Maximum rectal doses were lower with IMRT compared with HDR (average: 89.0% vs. 142.6%, respectively, p < 0.05). Moreover, the mean rectal dose was lower in IMRT plans compared with HDR plans with treatment prescribed either to the surface (average: 14.8% vs. 21.4%, respectively, p < 0.05) or to 0.5 cm (average: 19.6% vs. 33.5%, respectively, p < 0.05). IMRT plans had planning target volume (PTV) coverage comparable with HDR (average PTV minimum for treatment prescribed to 0.5 cm: 93.9% vs. 92.1%, p = 0.71, respectively) with less inhomogeneity (average PTV maximum: 110.8% vs. 381.6%, p < 0.05). Conclusion: Our dosimetric analysis suggests that when used in conjunction with a suitable immobilization system, IMRT may provide an alternative to HDR brachytherapy in women with early endometrial cancer after hysterectomy. However, more studies are needed to evaluate the clinical merit of the IMRT in these patients.

  16. Dynamic contrast-enhanced magnetic resonance imaging of osseous spine metastasis before and 1 hour after high-dose image-guided radiation therapy.

    PubMed

    Lis, Eric; Saha, Atin; Peck, Kyung K; Zatcky, Joan; Zelefsky, Michael J; Yamada, Yoshiya; Holodny, Andrei I; Bilsky, Mark H; Karimi, Sasan

    2017-01-01

    OBJECTIVE High-dose image-guided radiation therapy (HD IGRT) has been instrumental in mitigating some limitations of conventional RT. The recent emergence of dynamic contrast-enhanced (DCE) MRI to investigate tumor physiology can be used to verify the response of human tumors to HD IGRT. The purpose of this study was to evaluate the near-immediate effects of HD IGRT on spine metastases through the use of DCE MRI perfusion studies. METHODS Six patients with spine metastases from prostate, thyroid, and renal cell carcinoma who underwent HD IGRT were studied using DCE MRI prior to and 1 hour after HD IGRT. The DCE perfusion parameters plasma volume (Vp) and vascular permeability (Ktrans) were measured to assess the near-immediate and long-term tumor response. A Mann-Whitney U-test was performed to compare significant changes (at p ≤ 0.05) in perfusion parameters before and after RT. RESULTS The authors observed a precipitous drop in Vp within 1 hour of HD IGRT, with a mean decrease of 65.2%. A significant difference was found between Vp values for before and 1 hour after RT (p ≤ 0.05). No significant change was seen in Vp (p = 0.31) and Ktrans (p = 0.1) from 1 hour after RT to the first follow-up. CONCLUSIONS The data suggest that there is an immediate effect of HD IGRT on the vascularity of spine metastases, as demonstrated by a precipitous decrease in Vp. The DCE MRI studies can detect such changes within 1 hour after RT, and findings are concordant with existing animal models.

  17. Rectal Dose and Source Strength of the High-Dose-Rate Iridium-192 Both Affect Late Rectal Bleeding After Intracavitary Radiation Therapy for Uterine Cervical Carcinoma

    SciTech Connect

    Isohashi, Fumiaki; Yoshioka, Yasuo; Koizumi, Masahiko

    2010-07-01

    Purpose: The purpose of this study was to reconfirm our previous findings that the rectal dose and source strength both affect late rectal bleeding after high-dose-rate intracavitary brachytherapy (HDR-ICBT), by using a rectal dose calculated in accordance with the definitions of the International Commission on Radiation Units and Measurements Report 38 (ICRU{sub RP}) or of dose-volume histogram (DVH) parameters by the Groupe Europeen de Curietherapie of the European Society for Therapeutic Radiology and Oncology. Methods and Materials: Sixty-two patients who underwent HDR-ICBT and were followed up for 1 year or more were studied. The rectal dose for ICBT was calculated by using the ICRP{sub RP} based on orthogonal radiographs or the DVH parameters based on computed tomography (CT). The total dose was calculated as the biologically equivalent dose expressed in 2-Gy fractions (EQD{sub 2}). The relationship between averaged source strength or the EQD{sub 2} and late rectal bleeding was then analyzed. Results: When patients were divided into four groups according to rectal EQD{sub 2} ({>=} or =} or <2.4 cGy.m{sup 2}.h{sup -1}), the group with both a high EQD{sub 2} and a high source strength showed a significantly greater probability of rectal bleeding for ICRU{sub RP}, D{sub 2cc}, and D{sub 1cc}. The patients with a median rectal dose above the threshold level did not show a greater frequency of rectal bleeding unless the source strength exceeded 2.4 cGy.m{sup 2}.h{sup -1}. Conclusions: Our results obtained with data based on ICRU{sub RP} and CT-based DVH parameters indicate that rectal dose and source strength both affect rectal bleeding after HDR-ICBT.

  18. Preliminary Patient Reported Outcomes Analysis of 3DCRT versus IMRT on the High Dose Arm of the Radiation Therapy Oncology Group (RTOG) 0126 Prostate Cancer Trial

    PubMed Central

    Bruner, Deborah Watkins; Hunt, Daniel; Michalski, Jeff; Bosch, Walter; Galvin, James; Amin, Mahul; Xiao, Canhua; Bahary, Jean-Paul; Patel, Malti; Chafe, Susan; Rodrigues, George; Lau, Harold; Duclos, Marie; Baikadi, Madhava; Deshmukh, Snehal; Sandler, Howard

    2015-01-01

    Purpose A preliminary report of patient reported outcomes (PROs) between men receiving high-dose radiation therapy (RT) on RTOG 0126, a phase III dose-escalation trial treated with either 3-dimensional conformal RT (3D-CRT) or intensity modulated RT (IMRT). Methods 3D-CRT patients received 55.8 Gy to the prostate and proximal seminal vesicles (P+PSV) and allowed for an optional field reduction, then 23.4 Gy to prostate only. IMRT patients received 79.2 Gy to the P+PSV. PROs were assessed at 0 (baseline), 3, 6, 12, and 24 months and included bladder and bowel function assessed with the Functional Alterations due to Changes in Elimination (FACE) and erectile function assessed with the International Index of Erectile Function (IIEF). Analyses included those who completed all data at baseline and at least one follow-up and compared to an imputed data set. Results Of 763 patients randomized to the 79.2-Gy arm, 551 and 595 patients who responded to FACE, 505 and 577 who responded to the IIEF were included in the completed and imputed analyses, respectively. There were no significant differences between modalities for any of the FACE or IIEF subscale or total scores at any time point for either the completed or imputed data sets. Conclusions Despite significant reductions in dose and volume to normal structures using IMRT, this robust analysis of 3D-CRT and IMRT showed no difference in PRO bowel, bladder and sexual functions for similar doses delivered to the P+PSV for IMRT compared to 3D-CRT delivered to either the P+PSV or prostate alone. PMID:25847819

  19. Rectal dose and source strength of the high-dose-rate iridium-192 both affect late rectal bleeding after intracavitary radiation therapy for uterine cervical carcinoma.

    PubMed

    Isohashi, Fumiaki; Yoshioka, Yasuo; Koizumi, Masahiko; Suzuki, Osamu; Konishi, Koji; Sumida, Iori; Takahashi, Yutaka; Ogata, Toshiyuki; Kotsuma, Tadayuki; Inoue, Takehiro

    2010-07-01

    The purpose of this study was to reconfirm our previous findings that the rectal dose and source strength both affect late rectal bleeding after high-dose-rate intracavitary brachytherapy (HDR-ICBT), by using a rectal dose calculated in accordance with the definitions of the International Commission on Radiation Units and Measurements Report 38 (ICRU(RP)) or of dose-volume histogram (DVH) parameters by the Groupe Européen de Curietherapie of the European Society for Therapeutic Radiology and Oncology. Sixty-two patients who underwent HDR-ICBT and were followed up for 1 year or more were studied. The rectal dose for ICBT was calculated by using the ICRP(RP) based on orthogonal radiographs or the DVH parameters based on computed tomography (CT). The total dose was calculated as the biologically equivalent dose expressed in 2-Gy fractions (EQD(2)). The relationship between averaged source strength or the EQD(2) and late rectal bleeding was then analyzed. When patients were divided into four groups according to rectal EQD(2) (>or= or or= or <2.4 cGy.m(2).h(-1)), the group with both a high EQD(2) and a high source strength showed a significantly greater probability of rectal bleeding for ICRU(RP), D(2cc), and D(1cc). The patients with a median rectal dose above the threshold level did not show a greater frequency of rectal bleeding unless the source strength exceeded 2.4 cGy.m(2).h(-1). Our results obtained with data based on ICRU(RP) and CT-based DVH parameters indicate that rectal dose and source strength both affect rectal bleeding after HDR-ICBT. (c) 2010 Elsevier Inc. All rights reserved.

  20. Dose painting to treat single-lobe prostate cancer with hypofractionated high-dose radiation using targeted external beam radiation: Is it feasible?

    SciTech Connect

    Amini, Arya; Westerly, David C.; Waxweiler, Timothy V.; Ryan, Nicole; Raben, David

    2015-10-01

    Targeted focal therapy strategies for treating single-lobe prostate cancer are under investigation. In this planning study, we investigate the feasibility of treating a portion of the prostate to full-dose external beam radiation with reduced dose to the opposite lobe, compared with full-dose radiation delivered to the entire gland using hypofractionated radiation. For 10 consecutive patients with low- to intermediate-risk prostate cancer, 2 hypofractionated, single-arc volumetric-modulated arc therapy (VMAT) plans were designed. The first plan (standard hypofractionation regimen [STD]) included the entire prostate gland, treated to 70 Gy delivered in 28 fractions. The second dose painting plan (DP) encompassed the involved lobe treated to 70 Gy delivered in 28 fractions, whereas the opposing, uninvolved lobe received 50.4 Gy in 28 fractions. Mean dose to the opposing neurovascular bundle (NVB) was considerably lower for DP vs STD, with a mean dose of 53.9 vs 72.3 Gy (p < 0.001). Mean penile bulb dose was 18.6 Gy for DP vs 19.2 Gy for STD (p = 0.880). Mean rectal dose was 21.0 Gy for DP vs 22.8 Gy for STD (p = 0.356). Rectum V{sub 70} (the volume receiving ≥70 Gy) was 2.01% for DP vs 2.74% for STD (p = 0.328). Bladder V{sub 70} was 1.69% for DP vs 2.78% for STD (p = 0.232). Planning target volume (PTV) maximum dose points were 76.5 and 76.3 Gy for DP and STD, respectively (p = 0.760). This study demonstrates the feasibility of using VMAT for partial-lobe prostate radiation in patients with prostate cancer involving 1 lobe. Partial-lobe prostate plans appeared to spare adjacent critical structures including the opposite NVB.

  1. Indirect Tumor Cell Death After High-Dose Hypofractionated Irradiation: Implications for Stereotactic Body Radiation Therapy and Stereotactic Radiation Surgery

    SciTech Connect

    Song, Chang W.; Lee, Yoon-Jin; Griffin, Robert J.; Park, Inhwan; Koonce, Nathan A.; Hui, Susanta; Kim, Mi-Sook; Dusenbery, Kathryn E.; Sperduto, Paul W.; Cho, L. Chinsoo

    2015-09-01

    Purpose: The purpose of this study was to reveal the biological mechanisms underlying stereotactic body radiation therapy (SBRT) and stereotactic radiation surgery (SRS). Methods and Materials: FSaII fibrosarcomas grown subcutaneously in the hind limbs of C3H mice were irradiated with 10 to 30 Gy of X rays in a single fraction, and the clonogenic cell survival was determined with in vivo–in vitro excision assay immediately or 2 to 5 days after irradiation. The effects of radiation on the intratumor microenvironment were studied using immunohistochemical methods. Results: After cells were irradiated with 15 or 20 Gy, cell survival in FSaII tumors declined for 2 to 3 days and began to recover thereafter in some but not all tumors. After irradiation with 30 Gy, cell survival declined continuously for 5 days. Cell survival in some tumors 5 days after 20 to 30 Gy irradiation was 2 to 3 logs less than that immediately after irradiation. Irradiation with 20 Gy markedly reduced blood perfusion, upregulated HIF-1α, and increased carbonic anhydrase-9 expression, indicating that irradiation increased tumor hypoxia. In addition, expression of VEGF also increased in the tumor tissue after 20 Gy irradiation, probably due to the increase in HIF-1α activity. Conclusions: Irradiation of FSaII tumors with 15 to 30 Gy in a single dose caused dose-dependent secondary cell death, most likely by causing vascular damage accompanied by deterioration of intratumor microenvironment. Such indirect tumor cell death may play a crucial role in the control of human tumors with SBRT and SRS.

  2. Radiation-induced fibrosis in the boost area after three-dimensional conformal radiotherapy with a simultaneous integrated boost technique for early-stage breast cancer: A multivariable prediction model.

    PubMed

    Hammer, C; Maduro, J H; Bantema-Joppe, E J; van der Schaaf, A; van der Laan, H P; Langendijk, J A; Crijns, A P G

    2017-01-01

    To develop a multivariable prediction model for the risk of grade⩾2 fibrosis in the boost area after breast conserving surgery (BCS) followed by three-dimensional conformal radiotherapy (RT) with a simultaneous integrated photon boost (3D-CRT-SIB), five years after RT. This prospective cohort study included 1,030 patients treated with RT for breast cancer (stage 0-III), after BCS. Data regarding physician-rated fibrosis and dose-volume parameters were available in 546 patients. A multivariable logistic regression model for grade⩾2 fibrosis was generated. At 5years, grade⩾2 fibrosis was observed in 13.4% of the patients. The multivariable analysis resulted in a prediction model for grade⩾2 fibrosis in the boost area including three independent variables: patient age, breast volume receiving⩾55Gy (V55 CTV breast) and the maximum radiation dose in the breast (Dmax). A multivariable prediction model was developed including age, V55 CTV breast and Dmax for grade⩾2 fibrosis in the boost area after breast cancer RT using a 3D-CRT-SIB technique. This model can be used to estimate the risk of fibrosis and to optimize dose distributions aiming at reducing this risk. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. Comparison study of the partial-breast irradiation techniques: dosimetric analysis of three-dimensional conformal radiation therapy, electron beam therapy, and helical tomotherapy depending on various tumor locations.

    PubMed

    Kim, Min-Joo; Park, So-Hyun; Son, Seok-Hyun; Cheon, Keum-Seong; Choi, Byung-Ock; Suh, Tae-Suk

    2013-01-01

    The partial-breast irradiation (PBI) technique, an alternative to whole-breast irradiation, is a beam delivery method that uses a limited range of treatment volume. The present study was designed to determine the optimal PBI treatment modalities for 8 different tumor locations. Treatment planning was performed on computed tomography (CT) data sets of 6 patients who had received lumpectomy treatments. Tumor locations were classified into 8 subsections according to breast quadrant and depth. Three-dimensional conformal radiation therapy (3D-CRT), electron beam therapy (ET), and helical tomotherapy (H-TOMO) were utilized to evaluate the dosimetric effect for each tumor location. Conformation number (CN), radical dose homogeneity index (rDHI), and dose delivered to healthy tissue were estimated. The Kruskal-Wallis, Mann-Whitney U, and Bonferroni tests were used for statistical analysis. The ET approach showed good sparing effects and acceptable target coverage for the lower inner quadrant-superficial (LIQ-S) and lower inner quadrant-deep (LIQ-D) locations. The H-TOMO method was the least effective technique as no evaluation index achieved superiority for all tumor locations except CN. The ET method is advisable for treating LIQ-S and LIQ-D tumors, as opposed to 3D-CRT or H-TOMO, because of acceptable target coverage and much lower dose applied to surrounding tissue.

  4. Comparison study of the partial-breast irradiation techniques: Dosimetric analysis of three-dimensional conformal radiation therapy, electron beam therapy, and helical tomotherapy depending on various tumor locations

    SciTech Connect

    Kim, Min-Joo; Park, So-Hyun; Son, Seok-Hyun; Cheon, Keum-Seong; Choi, Byung-Ock; Suh, Tae-Suk

    2013-10-01

    The partial-breast irradiation (PBI) technique, an alternative to whole-breast irradiation, is a beam delivery method that uses a limited range of treatment volume. The present study was designed to determine the optimal PBI treatment modalities for 8 different tumor locations. Treatment planning was performed on computed tomography (CT) data sets of 6 patients who had received lumpectomy treatments. Tumor locations were classified into 8 subsections according to breast quadrant and depth. Three-dimensional conformal radiation therapy (3D-CRT), electron beam therapy (ET), and helical tomotherapy (H-TOMO) were utilized to evaluate the dosimetric effect for each tumor location. Conformation number (CN), radical dose homogeneity index (rDHI), and dose delivered to healthy tissue were estimated. The Kruskal-Wallis, Mann-Whitney U, and Bonferroni tests were used for statistical analysis. The ET approach showed good sparing effects and acceptable target coverage for the lower inner quadrant—superficial (LIQ-S) and lower inner quadrant—deep (LIQ-D) locations. The H-TOMO method was the least effective technique as no evaluation index achieved superiority for all tumor locations except CN. The ET method is advisable for treating LIQ-S and LIQ-D tumors, as opposed to 3D-CRT or H-TOMO, because of acceptable target coverage and much lower dose applied to surrounding tissue.

  5. Primary Analysis of the Phase II Component of a Phase I/II Dose Intensification Study Using Three-Dimensional Conformal Radiation Therapy and Concurrent Chemotherapy for Patients With Inoperable Non–Small-Cell Lung Cancer: RTOG 0117

    PubMed Central

    Bradley, Jeffrey D.; Bae, Kyounghwa; Graham, Mary V.; Byhardt, Roger; Govindan, Ramaswamy; Fowler, Jack; Purdy, James A.; Michalski, Jeff M.; Gore, Elizabeth; Choy, Hak

    2010-01-01

    Purpose Phase I of Radiation Therapy Oncology Group (RTOG) 0117 determined that 74 Gy was the maximum-tolerated dose with concurrent weekly carboplatin/paclitaxel chemotherapy for inoperable non–small-cell lung cancer (NSCLC). Phase II results are reported here. Patients and Methods Patients with unresectable stages I-III NSCLC were eligible. Chemotherapy consisted of weekly paclitaxel at 50 mg/m2 and carboplatin at area under the curve 2 mg/m2. The radiation dose was 74 Gy given in 37 fractions. Radiation therapy volumes included those of the gross tumor and involved nodes. The volume of lung at or exceeding 20 Gy (V20) was mandated to be ≤ 30%. Results Of the combined phase I/II enrollment, a total of 55 patients received 74 Gy, of whom 53 were evaluable. The median follow-up was 19.3 months (range, 0.9 to 57.9 months) for all patients and 25.4 months (range, 13.1 to 57.9 months) for those still alive. The median survival for all patients was 25.9 months. The percentage surviving at least 12 months was 75.5% (95% CI, 65.7% to 85.2%). The median overall survival (OS) and progression-free survival (PFS) times for stage III patients (n = 44) were 21.6 months and 10.8 months, respectively. OS and PFS rates at 12 months were 72.7% and 50.0%, respectively. Twelve patients experienced grade ≥ 3 lung toxicity (two patients had grade 5 lung toxicity). Conclusion The median survival time and OS rate at 12 months for this regimen are encouraging. These results serve as projection expectations for the high-dose radiation arms of the current RTOG 0617 phase III intergroup trial. PMID:20368547

  6. Preliminary patient-reported outcomes analysis of 3-dimensional radiation therapy versus intensity-modulated radiation therapy on the high-dose arm of the Radiation Therapy Oncology Group (RTOG) 0126 prostate cancer trial.

    PubMed

    Bruner, Deborah W; Hunt, Daniel; Michalski, Jeff M; Bosch, Walter R; Galvin, James M; Amin, Mahul; Xiao, Canhua; Bahary, Jean-Paul; Patel, Malti; Chafe, Susan; Rodrigues, George; Lau, Harold; Duclos, Marie; Baikadi, Madhava; Deshmukh, Snehal; Sandler, Howard M

    2015-07-15

    The authors analyzed a preliminary report of patient-reported outcomes (PROs) among men who received high-dose radiation therapy (RT) on Radiation Therapy Oncology Group study 0126 (a phase 3 dose-escalation trial) with either 3-dimensional conformal RT (3D-CRT) or intensity-modulated RT (IMRT). Patients in the 3D-CRT group received 55.8 gray (Gy) to the prostate and proximal seminal vesicles and were allowed an optional field reduction; then, they received 23.4 Gy to the prostate only. Patients in the IMRT group received 79.2 Gy to the prostate and proximal seminal vesicles. PROs were assessed at 0 months (baseline), 3 months, 6 months, 12 months, and 24 months and included bladder and bowel function assessed with the Functional Alterations due to Changes in Elimination (FACE) instrument and erectile function assessed with the International Index of Erectile Function (IIEF). Analyses included the patients who completed all data at baseline and for at least 1 follow-up assessment, and the results were compared with an imputed data set. Of 763 patients who were randomized to the 79.2-Gy arm, 551 patients and 595 patients who responded to the FACE instrument and 505 patients and 577 patients who responded to the IIEF were included in the completed and imputed analyses, respectively. There were no significant differences between modalities for any of the FACE or IIEF subscale scores or total scores at any time point for either the completed data set or the imputed data set. Despite significant reductions in dose and volume to normal structures using IMRT, this robust analysis of 3D-CRT and IMRT demonstrated no difference in patient-reported bowel, bladder, or sexual functions for similar doses delivered to the prostate and proximal seminal vesicles with IMRT compared with 3D-CRT delivered either to the prostate and proximal seminal vesicles or to the prostate alone. © 2015 American Cancer Society.

  7. Three-dimensional far-infrared imaging by using perspective thermal images

    NASA Astrophysics Data System (ADS)

    Barada, Daisuke

    2016-06-01

    This paper proposes a method to obtain three-dimensional thermal radiation distribution. In the method, multiple oblique projection thermal images are obtained by moving a target object and three-dimensional thermal radiation distribution is reconstructed based on projection-slice theorem. In experiment, incandescent light bulbs or a plant is used as a sample object. The three-dimensional position measured is coincided with actual position and the principle is experimentally verified.

  8. Is intensity-modulated radiotherapy better than conventional radiation treatment and three-dimensional conformal radiotherapy for mediastinal masses in patients with Hodgkin's disease, and is there a role for beam orientation optimization and dose constraints assigned to virtual volumes?

    SciTech Connect

    Girinsky, Theodore . E-mail: girinsky@igr.fr; Pichenot, Charlotte; Beaudre, Anne; Ghalibafian, Mithra; Lefkopoulos, Dimitri

    2006-01-01

    Purpose: To evaluate the role of beam orientation optimization and the role of virtual volumes (VVs) aimed at protecting adjacent organs at risk (OARs), and to compare various intensity-modulated radiotherapy (IMRT) setups with conventional treatment with anterior and posterior fields and three-dimensional conformal radiotherapy (3D-CRT). Methods and Materials: Patients with mediastinal masses in Hodgkin's disease were treated with combined modality therapy (three to six cycles of adriamycin, bleomycin, vinblastine, and dacarbazine [ABVD] before radiation treatment). Contouring and treatment planning were performed with Somavision and CadPlan Helios (Varian Systems, Palo Alto, CA). The gross tumor volume was determined according to the prechemotherapy length and the postchemotherapy width of the mediastinal tumor mass. A 10-mm isotropic margin was added for the planning target volume (PTV). Because dose constraints assigned to OARs led to unsatisfactory PTV coverage, VVs were designed for each patient to protect adjacent OARs. The prescribed dose was 40 Gy to the PTV, delivered according to guidelines from International Commission on Radiation Units and Measurements Report No. 50. Five different IMRT treatment plans were compared with conventional treatment and 3D-CRT. Results: Beam orientation was important with respect to the amount of irradiated normal tissues. The best compromise in terms of PTV coverage and protection of normal tissues was obtained with five equally spaced beams (5FEQ IMRT plan) using dose constraints assigned to VVs. When IMRT treatment plans were compared with conventional treatment and 3D-CRT, dose conformation with IMRT was significantly better, with greater protection of the heart, coronary arteries, esophagus, and spinal cord. The lungs and breasts in women received a slightly higher radiation dose with IMRT compared with conventional treatments. The greater volume of normal tissue receiving low radiation doses could be a cause for

  9. View Factor Calculation for Three-Dimensional Geometries.

    SciTech Connect

    1989-06-20

    Version 00 MCVIEW calculates the radiation geometric view factor between surfaces for three dimensional geometries with and without interposed third surface obstructions. It was developed to calculate view factors for input data to heat transfer analysis programs such as SCA-03/TRUMP, SCA-01/HEATING-5 and PSR-199/HEATING-6.

  10. A comprehensive dosimetric study of pancreatic cancer treatment using three-dimensional conformal radiation therapy (3DCRT), intensity-modulated radiation therapy (IMRT), volumetric-modulated radiation therapy (VMAT), and passive-scattering and modulated-scanning proton therapy (PT).

    PubMed

    Ding, Xuanfeng; Dionisi, Francesco; Tang, Shikui; Ingram, Mark; Hung, Chun-Yu; Prionas, Evangelos; Lichtenwalner, Phil; Butterwick, Ian; Zhai, Huifang; Yin, Lingshu; Lin, Haibo; Kassaee, Alireza; Avery, Stephen

    2014-01-01

    With traditional photon therapy to treat large postoperative pancreatic target volume, it often leads to poor tolerance of the therapy delivered and may contribute to interrupted treatment course. This study was performed to evaluate the potential advantage of using passive-scattering (PS) and modulated-scanning (MS) proton therapy (PT) to reduce normal tissue exposure in postoperative pancreatic cancer treatment. A total of 11 patients with postoperative pancreatic cancer who had been previously treated with PS PT in University of Pennsylvania Roberts Proton Therapy Center from 2010 to 2013 were identified. The clinical target volume (CTV) includes the pancreatic tumor bed as well as the adjacent high-risk nodal areas. Internal (iCTV) was generated from 4-dimensional (4D) computed tomography (CT), taking into account target motion from breathing cycle. Three-field and 4-field 3D conformal radiation therapy (3DCRT), 5-field intensity-modulated radiation therapy, 2-arc volumetric-modulated radiation therapy, and 2-field PS and MS PT were created on the patients' average CT. All the plans delivered 50.4Gy to the planning target volume (PTV). Overall, 98% of PTV was covered by 95% of the prescription dose and 99% of iCTV received 98% prescription dose. The results show that all the proton plans offer significant lower doses to the left kidney (mean and V18Gy), stomach (mean and V20Gy), and cord (maximum dose) compared with all the photon plans, except 3-field 3DCRT in cord maximum dose. In addition, MS PT also provides lower doses to the right kidney (mean and V18Gy), liver (mean dose), total bowel (V20Gy and mean dose), and small bowel (V15Gy absolute volume ratio) compared with all the photon plans and PS PT. The dosimetric advantage of PT points to the possibility of treating tumor bed and comprehensive nodal areas while providing a more tolerable treatment course that could be used for dose escalation and combining with radiosensitizing chemotherapy. Published by

  11. A comprehensive dosimetric study of pancreatic cancer treatment using three-dimensional conformal radiation therapy (3DCRT), intensity-modulated radiation therapy (IMRT), volumetric-modulated radiation therapy (VMAT), and passive-scattering and modulated-scanning proton therapy (PT)

    SciTech Connect

    Ding, Xuanfeng; Dionisi, Francesco; Tang, Shikui; Ingram, Mark; Hung, Chun-Yu; Prionas, Evangelos; Lichtenwalner, Phil; Butterwick, Ian; Zhai, Huifang; Yin, Lingshu; Lin, Haibo; Kassaee, Alireza; Avery, Stephen

    2014-07-01

    With traditional photon therapy to treat large postoperative pancreatic target volume, it often leads to poor tolerance of the therapy delivered and may contribute to interrupted treatment course. This study was performed to evaluate the potential advantage of using passive-scattering (PS) and modulated-scanning (MS) proton therapy (PT) to reduce normal tissue exposure in postoperative pancreatic cancer treatment. A total of 11 patients with postoperative pancreatic cancer who had been previously treated with PS PT in University of Pennsylvania Roberts Proton Therapy Center from 2010 to 2013 were identified. The clinical target volume (CTV) includes the pancreatic tumor bed as well as the adjacent high-risk nodal areas. Internal (iCTV) was generated from 4-dimensional (4D) computed tomography (CT), taking into account target motion from breathing cycle. Three-field and 4-field 3D conformal radiation therapy (3DCRT), 5-field intensity-modulated radiation therapy, 2-arc volumetric-modulated radiation therapy, and 2-field PS and MS PT were created on the patients’ average CT. All the plans delivered 50.4 Gy to the planning target volume (PTV). Overall, 98% of PTV was covered by 95% of the prescription dose and 99% of iCTV received 98% prescription dose. The results show that all the proton plans offer significant lower doses to the left kidney (mean and V{sub 18} {sub Gy}), stomach (mean and V{sub 20} {sub Gy}), and cord (maximum dose) compared with all the photon plans, except 3-field 3DCRT in cord maximum dose. In addition, MS PT also provides lower doses to the right kidney (mean and V{sub 18} {sub Gy}), liver (mean dose), total bowel (V{sub 20} {sub Gy} and mean dose), and small bowel (V{sub 15} {sub Gy} absolute volume ratio) compared with all the photon plans and PS PT. The dosimetric advantage of PT points to the possibility of treating tumor bed and comprehensive nodal areas while providing a more tolerable treatment course that could be used for dose

  12. [Three-dimensional printing and oral medicine].

    PubMed

    Hu, M

    2017-04-09

    After 30 years of development, three-dimensional printing technology has made great progress, and the model and surgical guide have been clinically applied. The three-dimensional printing of titanium and other metal prosthesis and dental crown after adequate research will be applied clinically, and three-dimensional bioprinting and related biological materials need further study. Three-dimensional printing provides opportunities for the development of oral medicine, which will change the way of clinical work, teaching and research. The dentists should integrate multi-disciplinary knowledge and understand the essence of new technology to meet the challenges of the era of digital medicine.

  13. Three dimensional identification card and applications

    NASA Astrophysics Data System (ADS)

    Zhou, Changhe; Wang, Shaoqing; Li, Chao; Li, Hao; Liu, Zhao

    2016-10-01

    Three dimensional Identification Card, with its three-dimensional personal image displayed and stored for personal identification, is supposed be the advanced version of the present two-dimensional identification card in the future [1]. Three dimensional Identification Card means that there are three-dimensional optical techniques are used, the personal image on ID card is displayed to be three-dimensional, so we can see three dimensional personal face. The ID card also stores the three-dimensional face information in its inside electronics chip, which might be recorded by using two-channel cameras, and it can be displayed in computer as three-dimensional images for personal identification. Three-dimensional ID card might be one interesting direction to update the present two-dimensional card in the future. Three-dimension ID card might be widely used in airport custom, entrance of hotel, school, university, as passport for on-line banking, registration of on-line game, etc...

  14. Three-dimensional map construction.

    PubMed

    Jenks, G F; Brown, D A

    1966-11-18

    Three-dimensional maps are useful tools which have been neglected for some time. They shouldbe more commonly used, and familiarity with the techniques discussed in this article should dispel any qualms anyone might ve about needing artistic talent to nstruct them. The saving in time esulting from the use of an anamorphoser provides a further incentive. The anamorphoser transformations discussed above were all prepared by using straight slits, oriented at right angles to each other and placed so that all planes of the elements were parallel to each other. It is possible to vary these conditions in an infinite number of ways and thereby produce nonparallel tranceformations. Some of these variations are illustrated in Fig. 10. All the illustrations in Fig. 10 are transformations of the planimetric weather map shown in Fig. 8A. The variations used for the maps of Fig. 10 are as follows. (A) All planes parallel, with a curved rear slit; (B) all planes parallel, with curved slits front and rear; ( C) all planes parallel, with S-shaped rear slit; (D) all planes parallel, with an undulating rear slit; (E) all planes parallel, with curved front and undulating rear slit; (F) plane of the original rotated on the horizontal axis-both slits curved; (G) plane of the original rotated on thevertical axis- both slits curved; (H) plane of the original rotated on the horizontal axis -both slits straight. These are only a few of the many transformations which can be made with an anamorphoser, butthey do point toward some interesting possibilities. For example, it appears that maps based onone projection might be altered to satisfy the coordinates of a completely different projection. Note, for example, the change of parallels from concave to convex curves (Figs. 8A and 10A) and the change from converging meridians to diverging meridians (Figs. 8A and l0G). Similarly, the grids of maps B, F, and H of Fig. 10 approximate projections which are quite different from the original. Other

  15. Preliminary Toxicity Analysis of 3-Dimensional Conformal Radiation Therapy Versus Intensity Modulated Radiation Therapy on the High-Dose Arm of the Radiation Therapy Oncology Group 0126 Prostate Cancer Trial

    SciTech Connect

    Michalski, Jeff M.; Yan, Yan; Watkins-Bruner, Deborah; Bosch, Walter R.; Winter, Kathryn; Galvin, James M.; Bahary, Jean-Paul; Morton, Gerard C.; Parliament, Matthew B.; Sandler, Howard M.

    2013-12-01

    Purpose: To give a preliminary report of clinical and treatment factors associated with toxicity in men receiving high-dose radiation therapy (RT) on a phase 3 dose-escalation trial. Methods and Materials: The trial was initiated with 3-dimensional conformal RT (3D-CRT) and amended after 1 year to allow intensity modulated RT (IMRT). Patients treated with 3D-CRT received 55.8 Gy to a planning target volume that included the prostate and seminal vesicles, then 23.4 Gy to prostate only. The IMRT patients were treated to the prostate and proximal seminal vesicles to 79.2 Gy. Common Toxicity Criteria, version 2.0, and Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer late morbidity scores were used for acute and late effects. Results: Of 763 patients randomized to the 79.2-Gy arm of Radiation Therapy Oncology Group 0126 protocol, 748 were eligible and evaluable: 491 and 257 were treated with 3D-CRT and IMRT, respectively. For both bladder and rectum, the volumes receiving 65, 70, and 75 Gy were significantly lower with IMRT (all P<.0001). For grade (G) 2+ acute gastrointestinal/genitourinary (GI/GU) toxicity, both univariate and multivariate analyses showed a statistically significant decrease in G2+ acute collective GI/GU toxicity for IMRT. There were no significant differences with 3D-CRT or IMRT for acute or late G2+ or 3+ GU toxicities. Univariate analysis showed a statistically significant decrease in late G2+ GI toxicity for IMRT (P=.039). On multivariate analysis, IMRT showed a 26% reduction in G2+ late GI toxicity (P=.099). Acute G2+ toxicity was associated with late G3+ toxicity (P=.005). With dose–volume histogram data in the multivariate analysis, RT modality was not significant, whereas white race (P=.001) and rectal V70 ≥15% were associated with G2+ rectal toxicity (P=.034). Conclusions: Intensity modulated RT is associated with a significant reduction in acute G2+ GI/GU toxicity. There is a trend for a

  16. Initial Efficacy Results of RTOG 0319: Three-Dimensional Conformal Radiation Therapy (3D-CRT) Confined to the Region of the Lumpectomy Cavity for Stage I/ II Breast Carcinoma

    SciTech Connect

    Vicini, Frank; Winter, Kathryn; Wong, John

    2010-07-15

    Purpose: This prospective study (Radiation Therapy Oncology Group 0319) examines the use of three-dimensional conformal external beam radiotherapy (3D-CRT) to deliver accelerated partial breast irradiation (APBI). Initial data on efficacy and toxicity are presented. Methods and Materials: Patients with Stage I or II breast cancer with lesions {<=}3 cm, negative margins and with {<=}3 positive nodes were eligible. The 3D-CRT was 38.5 Gy in 3.85 Gy/fraction delivered 2x/day. Ipsilateral breast, ipsilateral nodal, contralateral breast, and distant failure (IBF, INF, CBF, DF) were estimated using the cumulative incidence method. Mastectomy-free, disease-free, and overall survival (MFS, DFS, OS) were recorded. The National Cancer Institute Common Terminology Criteria for Adverse Events, version 3, was used to grade acute and late toxicity. Results: Fifty-eight patients were entered and 52 patients are eligible and evaluable for efficacy. The median age of patients was 61 years with the following characteristics: 46% tumor size <1 cm; 87% invasive ductal histology; 94% American Joint Committee on Cancer Stage I; 65% postmenopausal; 83% no chemotherapy; and 71% with no hormone therapy. Median follow-up is 4.5 years (1.7-4.8). Four-year estimates (95% CI) of efficacy are: IBF 6% (0-12%) [4% within field (0-9%)]; INF 2% (0-6%); CBF 0%; DF 8% (0-15%); MFS 90% (78-96%); DFS 84% (71-92%); and OS 96% (85-99%). Only two (4%) Grade 3 toxicities were observed. Conclusions: Initial efficacy and toxicity using 3D-CRT to deliver APBI appears comparable to other experiences with similar follow-up. However, additional patients, further follow-up, and mature Phase III data are needed to evaluate the extent of application, limitations, and value of this particular form of APBI.

  17. Three-dimensional gravity and string ghosts

    SciTech Connect

    Carlip, S. ); Kogan, I.I. )

    1991-12-23

    It is known that much of the structure of string theory can be derived from three-dimensional topological field theory and gravity. We show here that, at least for simple topologies, the string diffeomorphism ghosts can also be explained in terms of three-dimensional physics.

  18. Weekly chemotherapy with radiation versus high-dose cisplatin with radiation as organ preservation for patients with HPV-positive and HPV-negative locally advanced squamous cell carcinoma of the oropharynx.

    PubMed

    Dobrosotskaya, Irina Y; Bellile, Emily; Spector, Matthew E; Kumar, Bhavna; Feng, Felix; Eisbruch, Avraham; Wolf, Gregory T; Prince, Mark E P; Moyer, Jeffrey S; Teknos, Theodoros; Chepeha, Douglas B; Walline, Heather M; McHugh, Jonathan B; Cordell, Kitrina G; Ward, P Daniel; Byrd, Serena; Maxwell, Jessica H; Urba, Susan; Bradford, Carol R; Carey, Thomas E; Worden, Francis P

    2014-05-01

    Optimal treatment for locally advanced squamous cell carcinoma of the oropharynx (SCCOP) is not well defined. Here we retrospectively compare survival and toxicities from 2 different organ preservation protocols. The matched dataset consisted of 35 patients from each trial matched for age, stage, smoking, and tumor human papillomavirus (HPV) status. Patients in the University of Michigan Cancer Center (UMCC) trial 9921 were treated with induction chemotherapy (IC) followed by high-dose cisplatin and radiation in responders or surgery in nonresponders. Patients in the UMCC trial 0221 were treated with weekly carboplatin and paclitaxel and radiation. Survival was comparable for both studies and did not differ significantly across each trial after stratifying by HPV status. Grade 3 and 4 toxicities were more frequent in UMCC 9921. At 6 months posttreatment, gastrostomy tube (G-tube) dependence was not statistically different. These data suggest that survival outcomes in patients with locally advanced SCCOP are not compromised with weekly chemotherapy and radiation therapy, and such treatment is generally more tolerable. Copyright © 2013 Wiley Periodicals, Inc.

  19. Three-dimensional reconstruction of Haversian systems in human cortical bone using synchrotron radiation-based micro-CT: morphology and quantification of branching and transverse connections across age.

    PubMed

    Maggiano, Isabel S; Maggiano, Corey M; Clement, John G; Thomas, C David L; Carter, Yasmin; Cooper, David M L

    2016-05-01

    This study uses synchrotron radiation-based micro-computed tomography (CT) scans to reconstruct three-dimensional networks of Haversian systems in human cortical bone in order to observe and analyse interconnectivity of Haversian systems and the development of total Haversian networks across different ages. A better knowledge of how Haversian systems interact with each other is essential to improve understanding of remodeling mechanisms and bone maintenance; however, previous methodological approaches (e.g. serial sections) did not reveal enough detail to follow the specific morphology of Haversian branching, for example. Accordingly, the aim of the present study was to identify the morphological diversity of branching patterns and transverse connections, and to understand how they change with age. Two types of branching morphologies were identified: lateral branching, resulting in small osteon branches bifurcating off of larger Haversian canals; and dichotomous branching, the formation of two new osteonal branches from one. The reconstructions in this study also suggest that Haversian systems frequently target previously existing systems as a path for their course, resulting in a cross-sectional morphology frequently referred to as 'type II osteons'. Transverse connections were diverse in their course from linear to oblique to curvy. Quantitative assessment of age-related trends indicates that while in younger human individuals transverse connections were most common, in older individuals more evidence of connections resulting from Haversian systems growing inside previously existing systems was found. Despite these changes in morphological characteristics, a relatively constant degree of overall interconnectivity is maintained throughout life. Altogether, the present study reveals important details about Haversian systems and their relation to each other that can be used towards a better understanding of cortical bone remodeling as well as a more accurate

  20. Three Dimensional Illustrating--Three-Dimensional Vision and Deception of Sensibility

    ERIC Educational Resources Information Center

    Szállassy, Noémi; Gánóczy, Anita; Kriska, György

    2009-01-01

    The wide-spread digital photography and computer use gave the opportunity for everyone to make three-dimensional pictures and to make them public. The new opportunities with three-dimensional techniques give chance for the birth of new artistic photographs. We present in detail the biological roots of three-dimensional visualization, the phenomena…

  1. Microlaser-based three-dimensional display

    NASA Astrophysics Data System (ADS)

    Takeuchi, Eric B.; Bergstedt, Robert; Hargis, David E.; Higley, Paul D.

    1999-08-01

    Three dimensional (3D) displays are critical for viewing complex multi-dimensional information and for viewing representations of the three dimensional real world. A teaming arrangement between Laser Power Corporation (LPC) and Specialty Devices, Inc. (SDI) has led to the feasibility demonstration of a directly-viewed three dimensional volumetric display. LPC has developed red, green, and blue (RGB) diode pumped solid state microlaser display technology for use as a high resolution, high brightness display engine for the three dimensional display. Concurrently, SDI has developed a unique technology for viewing high resolution three dimensional volumetric images without external viewing aids (eye wear). When coupled to LPC's display engine, the resultant all solid state three dimensional display presets a true, physical three dimensionality which is directly viewable from all angles by multiple viewers without additional viewing equipment (eye wear). The resultant volumetric display will further enable applications such as the 'virtual sandbox,' visualization of radar and sonar data, air traffic control, remote surgery and diagnostics, and CAD workstations.

  2. Three-dimensional topological insulator based nanospaser

    NASA Astrophysics Data System (ADS)

    Paudel, Hari P.; Apalkov, Vadym; Stockman, Mark I.

    2016-04-01

    After the discovery of the spaser (surface plasmon amplification by stimulated emission of radiation), first proposed by Bergman and Stockman in 2003, it has become possible to deliver optical energy beyond the diffraction limit and generate an intense source of an optical field. The spaser is a nanoplasmonic counterpart of a laser. One of the major advantages of the spaser is its size: A spaser is a truly nanoscopic device whose size can be made smaller than the skin depth of a material to a size as small as the nonlocality radius (˜1 nm). Recently, an electrically pumped graphene based nanospaser has been proposed that operates in the midinfrared region and utilizes a nanopatch of graphene as a source of plasmons and a quantum-well cascade as its gain medium. Here we propose an optically pumped nanospaser based on three-dimensional topological insulator (3D TI) materials, such as Bi2Se3 , that operates at an energy close to the bulk band-gap energy ˜0.3 eV and uses the surface as a source for plasmons and its bulk as a gain medium. Population inversion is obtained in the bulk and the radiative energy of the exciton recombination is transferred to the surface plasmons of the same material to stimulate spasing action. This is truly a nanoscale spaser as it utilizes the same material for dual purposes. We show theoretically the possibility of achieving spasing with a 3D TI. As the spaser operates in the midinfrared spectral region, it can be a useful device for a number of applications, such as nanoscopy, nanolithography, nanospectroscopy, and semiclassical information processing.

  3. Three-dimensional laser window formation

    NASA Technical Reports Server (NTRS)

    Verhoff, Vincent G.

    1992-01-01

    The NASA Lewis Research Center has developed and implemented a unique process for forming flawless three-dimensional laser windows. These windows represent a major part of specialized, nonintrusive laser data acquisition systems used in a variety of compressor and turbine research test facilities. This report discusses in detail the aspects of three-dimensional laser window formation. It focuses on the unique methodology and the peculiarities associated with the formation of these windows. Included in this discussion are the design criteria, bonding mediums, and evaluation testing for three-dimensional laser windows.

  4. Three-dimensional velocity measurements using LDA

    NASA Astrophysics Data System (ADS)

    Buchhave, Preben

    The design requirements for and development of an LDA that measures the three components of the fluid velocity vector are described. The problems encountered in LDA measurements in highly turbulent flows, multivariate response, velocity bias, spatial resolution, temporal resolution, and dynamic range, are discussed. The use of the fringe and/or the reference beam methods to measure the three velocity components, and the use of color, frequency shift, and polarization to separate three velocity projections are examined. Consideration is given to the coordinate transformation, the presentation of three-dimensional LDA data, and the possibility of three-dimensional bias correction. Procedures for conducting three-dimensional LDA measurements are proposed.

  5. {sup 18}F-Choline Positron Emission Tomography/Computed Tomography–Driven High-Dose Salvage Radiation Therapy in Patients With Biochemical Progression After Radical Prostatectomy: Feasibility Study in 60 Patients

    SciTech Connect

    D'Angelillo, Rolando M.; Sciuto, Rosa; Ramella, Sara; Papalia, Rocco; Jereczek-Fossa, Barbara A.; Trodella, Luca E.; Fiore, Michele; Gallucci, Michele; Maini, Carlo L.; Trodella, Lucio

    2014-10-01

    Purpose: To retrospectively review data of a cohort of patients with biochemical progression after radical prostatectomy, treated according to a uniform institutional treatment policy, to evaluate toxicity and feasibility of high-dose salvage radiation therapy (80 Gy). Methods and Materials: Data on 60 patients with biochemical progression after radical prostatectomy between January 2009 and September 2011 were reviewed. The median value of prostate-specific antigen before radiation therapy was 0.9 ng/mL. All patients at time of diagnosis of biochemical recurrence underwent dynamic {sup 18}F-choline positron emission tomography/computed tomography (PET/CT), which revealed in all cases a local recurrence. High-dose salvage radiation therapy was delivered up to total dose of 80 Gy to 18F-choline PET/CT-positive area. Toxicity was recorded according to the Common Terminology Criteria for Adverse Events, version 3.0, scale. Results: Treatment was generally well tolerated: 54 patients (90%) completed salvage radiation therapy without any interruption. Gastrointestinal grade ≥2 acute toxicity was recorded in 6 patients (10%), whereas no patient experienced a grade ≥2 genitourinary toxicity. No grade 4 acute toxicity events were recorded. Only 1 patient (1.7%) experienced a grade 2 gastrointestinal late toxicity. With a mean follow-up of 31.2 months, 46 of 60 patients (76.6%) were free of recurrence. The 3-year biochemical progression-free survival rate was 72.5%. Conclusions: At early follow-up, {sup 18}F-choline PET/CT-driven high-dose salvage radiation therapy seems to be feasible and well tolerated, with a low rate of toxicity.

  6. Three Dimensional Optic Tissue Culture and Process

    NASA Technical Reports Server (NTRS)

    OConnor, Kim C. (Inventor); Spaulding, Glenn F. (Inventor); Goodwin, Thomas J. (Inventor); Aten, Laurie A. (Inventor); Francis, Karen M. (Inventor); Caldwell, Delmar R. (Inventor); Prewett, Tacey L. (Inventor); Fitzgerald, Wendy S. (Inventor)

    1999-01-01

    A process for artificially producing three-dimensional optic tissue has been developed. The optic cells are cultured in a bioireactor at low shear conditions. The tissue forms as normal, functional tissue grows with tissue organization and extracellular matrix formation.

  7. Three dimensional optic tissue culture and process

    NASA Technical Reports Server (NTRS)

    Spaulding, Glenn F. (Inventor); Prewett, Tacey L. (Inventor); Goodwin, Thomas J. (Inventor); Francis, Karen M. (Inventor); Cardwell, Delmar R. (Inventor); Oconnor, Kim (Inventor); Fitzgerald, Wendy S. (Inventor); Aten, Laurie A. (Inventor)

    1994-01-01

    A process for artificially producing three-dimensional optic tissue has been developed. The optic cells are cultured in a bioreactor at low shear conditions. The tissue forms normal, functional tissue organization and extracellular matrix.

  8. Device fabrication: Three-dimensional printed electronics

    NASA Astrophysics Data System (ADS)

    Lewis, Jennifer A.; Ahn, Bok Y.

    2015-02-01

    Can three-dimensional printing enable the mass customization of electronic devices? A study that exploits this method to create light-emitting diodes based on 'quantum dots' provides a step towards this goal.

  9. Three-dimensional printing of surgical anatomy.

    PubMed

    Powers, Mary K; Lee, Benjamin R; Silberstein, Jonathan

    2016-05-01

    Over the past decade, three-dimensional printing for the medical field has been expanding rapidly throughout all of medicine. This manuscript reviews the current and potential applications for three-dimensional printing, including education, presurgical planning, surgical simulation, bioprinting, and printed surgical equipment. Three-dimensional printing has proved most relevant in the fields of craniofacial, plastic, orthopedics, and especially, urologic surgery. This review focuses on several examples of how three-dimensional printing can be utilized, with emphasis on renal models for renal cell carcinoma, ureteral stents, and staghorn calculus. From an education standpoint, both patients and residents can benefit from the use of three-dimensional printed models, and even skilled surgeons report better understanding of complex procedures by using printed models. Three-dimensional printing in the field of medicine is growing quickly, and will soon be incorporated into the way residents are taught and patients are educated. For surgical simulation in a variety of disease processes, this will be particularly useful for urologic surgery.

  10. Three-dimensional imaging of dislocations by X-ray diffraction laminography

    SciTech Connect

    Haenschke, D.; Helfen, L.; Altapova, V.; Danilewsky, A.; Baumbach, T.

    2012-12-10

    Synchrotron radiation laminography with X-ray diffraction contrast enables three-dimensional imaging of dislocations in monocrystalline wafers. We outline the principle of the technique, the required experimental conditions, and the reconstruction procedure. The feasibility and the potential of the method are demonstrated by three-dimensional imaging of dislocation loops in an indent-damaged and annealed silicon wafer.

  11. Viscosity of alkaline suspensions of ground black and white pepper samples: An indication or an identification of high dose radiation treatment?

    NASA Astrophysics Data System (ADS)

    Schreiber, G. A.; Leffke, A.; Mager, M.; Helle, N.; Bögl, K. W.

    1994-11-01

    Forty-nine pepper samples were taken from retail food stores of different cities in Germany. Most of the black and all white pepper samples showed high viscosity values after jellification in alkaline solution. After irradiation with a γ-ray dose of 6 kGy, viscosity was largely reduced in each case. Some black pepper samples showed a low viscosity level already before irradiation. However, thermoluminescence analysis did not reveal any sign for irradiation treatment prior to examination. Furthermore, the low viscosity level of these samples could not be correlated with a low starch content. It is concluded that the viscosity levels of irradiated white pepper samples clearly reveal high dose irradiation treatment. In case of black peppers it is judged that the method can be used to screen for irradiated samples since it is fast, easy and cheap. However, a positive result should be confirmed by another technique, e.g. thermoluminescence.

  12. Changes in the thermal properties of PADC film-based nuclear track detectors produced by high doses of γ-radiation

    NASA Astrophysics Data System (ADS)

    Saad, A. F.; Saad, Noura; Abdalla, Y. K.

    2014-04-01

    Irradiation effects on the thermal properties of poly allyl diglycol carbonate (PADC) polymer-based nuclear track detectors (in the form of CR-39) have been investigated. PADC films were exposed to γ-rays at high doses ranging from 5.0 × 105 to 1.0 × 106 Gy. The induced modifications were analyzed by means of thermogravimetric analysis, which indicated that the PADC film decomposed in three main stages. The activation energy for thermal decomposition was determined using a type of Arrhenius equation based on the TGA experimental results. This study presents quantitative results showing that the exposed PADC films do not undergo continual further degradation from high-energy γ-photons with increase in dose. The experimental results also provide insight into the specific property changes induced by γ-rays, which may be of use for industrial applications.

  13. Assessment of three-dimensional set-up errors using megavoltage computed tomography (MVCT) during image-guided intensity-modulated radiation therapy (IMRT) for craniospinal irradiation (CSI) on helical tomotherapy (HT).

    PubMed

    Gupta, Tejpal; Upasani, Maheshkumar; Master, Zubin; Patil, Anita; Phurailatpam, Reena; Nojin, Siji; Kannan, Sadhana; Godasastri, Jayant; Jalali, Rakesh

    2015-02-01

    The purpose of this study was to assess three-dimensional (3D) set-up errors using megavoltage computed tomography (MVCT) during image-guided intensity-modulated radiation therapy (IMRT) for supine craniospinal irradiation (CSI) on helical tomotherapy (HT). Patients were immobilized in a customized 4-clamp thermoplastic head mask with or without whole-body vacuum cradle. Set-up was based primarily on a set of cranial fiducial markers. MVCT scans were acquired and co-registered with planning scan separately at three different levels (brain, upper, and lower spine) at every fraction. Only translational displacements were analysed, wherein positive sign denotes deviation in anterior, left, and superior direction; while negative sign denotes deviation in posterior, right, and inferior direction. Mean displacements, systematic, and random errors of the study population were calculated at all three levels separately. Local residual uncertainty of the upper and lower spine was also derived assuming perfect co-registration of the skull. Set-up margins for clinical target volume (CTV) to planning target volume (PTV) were derived at these three levels separately using published margin recipes. Data from 1868 co-registrations in 674 fractions on 33 patients was included. The mean displacements in the lateral, longitudinal, and vertical directions were -1.21, -1.36, and 1.38 mm; -1.25, -0.34, and 0.65 mm; and -1.47, -2.78, and 0.22 mm for the brain; upper spine; and lumbar spine respectively. The corresponding 3D vector of displacement was 2.28; 1.45; and 3.15 mm respectively. There was a distinct systematic trend towards increasing inaccuracy from the brain towards the lower spine. Using Stroom's formula, the minimum recommended CTV to PTV margins in absence of daily image-guidance were 6.5; 7.0; and 9.5 mm for the brain; upper spine; and lower spine respectively. This increased to 7.5; 8.5; and 11.5 mm using van Herk's formula. Subset and sensitivity analyses

  14. Three-dimensional separation and reattachment

    NASA Technical Reports Server (NTRS)

    Peake, D. J.; Tobak, M.

    1982-01-01

    The separation of three dimensional turbulent boundary layers from the lee of flight vehicles at high angles of attack is investigated. The separation results in dominant, large scale, coiled vortex motions that pass along the body in the general direction of the free stream. In all cases of three dimensional flow separation and reattachment, the assumption of continuous vector fields of skin friction lines and external flow streamlines, coupled with simple laws of topology, provides a flow grammar whose elemental constituents are the singular points: the nodes, spiral nodes (foci), and saddles. The phenomenon of three dimensional separation may be construed as either a local or a global event, depending on whether the skin friction line that becomes a line of separation originates at a node or a saddle point.

  15. Topology of three-dimensional separated flows

    NASA Technical Reports Server (NTRS)

    Tobak, M.; Peake, D. J.

    1981-01-01

    Based on the hypothesis that patterns of skin-friction lines and external streamlines reflect the properties of continuous vector fields, topology rules define a small number of singular points (nodes, saddle points, and foci) that characterize the patterns on the surface and on particular projections of the flow (e.g., the crossflow plane). The restricted number of singular points and the rules that they obey are considered as an organizing principle whose finite number of elements can be combined in various ways to connect together the properties common to all steady three dimensional viscous flows. Introduction of a distinction between local and global properties of the flow resolves an ambiguity in the proper definition of a three dimensional separated flow. Adoption of the notions of topological structure, structural stability, and bifurcation provides a framework to describe how three dimensional separated flows originate and succeed each other as the relevant parameters of the problem are varied.

  16. Three-dimensional separation and reattachment

    NASA Technical Reports Server (NTRS)

    Peake, D. J.; Tobak, M.

    1982-01-01

    The separation of three dimensional turbulent boundary layers from the lee of flight vehicles at high angles of attack is investigated. The separation results in dominant, large scale, coiled vortex motions that pass along the body in the general direction of the free stream. In all cases of three dimensional flow separation and reattachment, the assumption of continuous vector fields of skin friction lines and external flow streamlines, coupled with simple laws of topology, provides a flow grammar whose elemental constituents are the singular points: the nodes, spiral nodes (foci), and saddles. The phenomenon of three dimensional separation may be constrained as either a local or a global event, depending on whether the skin friction line that becomes a line of separation originates at a node or a saddle point.

  17. Vision in our three-dimensional world.

    PubMed

    Parker, Andrew J

    2016-06-19

    Many aspects of our perceptual experience are dominated by the fact that our two eyes point forward. Whilst the location of our eyes leaves the environment behind our head inaccessible to vision, co-ordinated use of our two eyes gives us direct access to the three-dimensional structure of the scene in front of us, through the mechanism of stereoscopic vision. Scientific understanding of the different brain regions involved in stereoscopic vision and three-dimensional spatial cognition is changing rapidly, with consequent influences on fields as diverse as clinical practice in ophthalmology and the technology of virtual reality devices.This article is part of the themed issue 'Vision in our three-dimensional world'. © 2016 The Author(s).

  18. Vision in our three-dimensional world

    PubMed Central

    2016-01-01

    Many aspects of our perceptual experience are dominated by the fact that our two eyes point forward. Whilst the location of our eyes leaves the environment behind our head inaccessible to vision, co-ordinated use of our two eyes gives us direct access to the three-dimensional structure of the scene in front of us, through the mechanism of stereoscopic vision. Scientific understanding of the different brain regions involved in stereoscopic vision and three-dimensional spatial cognition is changing rapidly, with consequent influences on fields as diverse as clinical practice in ophthalmology and the technology of virtual reality devices. This article is part of the themed issue ‘Vision in our three-dimensional world’. PMID:27269595

  19. Three dimensional boundary conditions in supersonic flow

    NASA Technical Reports Server (NTRS)

    Rudman, S.; Marconi, F.

    1981-01-01

    A theoretical analysis of the flow pattern at a solid surface in three dimensional supersonic flow is presented. The additional information necessary to overcome the nonuniqueness associated with the body tangency condition in three dimensions was developed. The analysis is based on the fact that three dimensional waves propagate locally exactly as they do in axisymmetric flow when viewed in the osculating plane to the streamline. The supersonic flow over an infinite swept corner is examined by both the classical solution and the three dimensional solution in the osculating plane and the results are shown to be identical. A simple numerical algorithm is proposed which accounts for the three wave surfaces that interact at a solid boundary.

  20. Three-dimensional stability of vortex arrays

    NASA Astrophysics Data System (ADS)

    Robinson, A. C.; Saffman, P. G.

    1982-12-01

    The stability to three-dimensional disturbances of three classical steady vortex configurations in an incompressible inviscid fluid is studied in the limit of small vortex cross-sectional area and long axial disturbance wavelength. The configurations examined are the single infinite vortex row, the Karman vortex street of staggered vortices and the symmetric vortex street. It is shown that the single row is most unstable to a two-dimensional disturbance, while the Karman vortex street is most unstable to a three-dimensional disturbance over a significant range of street spacing ratios. The symmetric vortex street is found to be most unstable to three-dimensional or two-dimensional symmetric disturbances depending on the spacing ratio of the street. Short remarks are made concerning the relevance of the calculations to the observed instabilities in free shear layer, wake and boundary-layer type flows.

  1. Fabrication of three dimensional microstructure fiber

    NASA Astrophysics Data System (ADS)

    Luo, Ying; Ma, Jie; Chen, Zhe; Lu, Huihui; Zhong, Yongchun

    2015-05-01

    A method of fabricating three dimensional (3D) microstructured fiber is presented. Polystyrene (PS) microspheres were coated around the surface of a micro-fiber through isothermal heating evaporation induced self-assembly method. Scanning electron microscopy (SEM) image shows that the colloidal crystal has continuous, uniform, and well-ordered face-centered cubic (FCC) structure, with [111] crystallographic direction normal to the surface of micro-fiber. This micro-fiber with three-dimensional photonic crystals structure is very useful in the applications of micro-fiber sensors or filters.

  2. Three-dimensional topological insulators and bosonization

    NASA Astrophysics Data System (ADS)

    Cappelli, Andrea; Randellini, Enrico; Sisti, Jacopo

    2017-05-01

    Massless excitations at the surface of three-dimensional time-reversal invariant topological insulators possess both fermionic and bosonic descriptions, originating from band theory and hydrodynamic BF theory, respectively. We analyze the corresponding field theories of the Dirac fermion and compactified boson and compute their partition functions on the three-dimensional torus geometry. We then find some non-dynamic exact properties of bosonization in (2+1) dimensions, regarding fermion parity and spin sectors. Using these results, we extend the Fu-Kane-Mele stability argument to fractional topological insulators in three dimensions.

  3. Three-dimensional displays and stereo vision.

    PubMed

    Westheimer, Gerald

    2011-08-07

    Procedures for three-dimensional image reconstruction that are based on the optical and neural apparatus of human stereoscopic vision have to be designed to work in conjunction with it. The principal methods of implementing stereo displays are described. Properties of the human visual system are outlined as they relate to depth discrimination capabilities and achieving optimal performance in stereo tasks. The concept of depth rendition is introduced to define the change in the parameters of three-dimensional configurations for cases in which the physical disposition of the stereo camera with respect to the viewed object differs from that of the observer's eyes.

  4. Three-dimensional crack closure behavior

    NASA Technical Reports Server (NTRS)

    Dawicke, D. S.; Grandt, A. F., Jr.; Newman, J. C., Jr.

    1990-01-01

    A crack closure measurement technique involving fatigue striations was used to produce a three-dimensional crack opening load profile for 2024-T351 aluminum alloy. The crack opening load profile, determined through the specimen thickness, was compared with crack opening load measurements made with strain gages and displacement gages. The results of this study indicate that a significant three-dimensional variation in crack closure behavior occurs in the alloy examined. An understanding of this phehomenon is important in understanding crack growth behavior, predicting crack shape changes, and interpreting 'standard' crack closure measurement techniques.

  5. Three-dimensional stochastic vortex flows

    NASA Astrophysics Data System (ADS)

    Esposito, R.; Pulvirenti, M.

    1989-08-01

    It is well known that the dynamics of point vortices approximate, under suitable limits, the two-dimensional Euler flow for an ideal fluid. To find particle models for three-dimensional flows is a more intricate problem. A stochastic version of the algorithm introduced by Beale amd Maida (1982) for simulating the behavior of a three-dimensional Euler flow is introduced here, and convergence to the Navier-Stokes (NS) flow in R exp 3 is shown. The result is based on a stochastic Lagrangian picture of the NS equations.

  6. Three-dimensional magnetic bubble memory system

    NASA Technical Reports Server (NTRS)

    Stadler, Henry L. (Inventor); Katti, Romney R. (Inventor); Wu, Jiin-Chuan (Inventor)

    1994-01-01

    A compact memory uses magnetic bubble technology for providing data storage. A three-dimensional arrangement, in the form of stacks of magnetic bubble layers, is used to achieve high volumetric storage density. Output tracks are used within each layer to allow data to be accessed uniquely and unambiguously. Storage can be achieved using either current access or field access magnetic bubble technology. Optical sensing via the Faraday effect is used to detect data. Optical sensing facilitates the accessing of data from within the three-dimensional package and lends itself to parallel operation for supporting high data rates and vector and parallel processing.

  7. Interstitial high-dose-rate brachytherapy as salvage treatment for locally recurrent prostate cancer after definitive radiation therapy: Toxicity and 5-year outcome.

    PubMed

    Jiang, Ping; van der Horst, Christof; Kimmig, Bernhard; Zinsser, Fabian; Poppe, Bjoern; Luetzen, Ulf; Juenemann, Klaus-Peter; Dunst, Juergen; Siebert, Frank-André

    We report our results with interstitial high-dose-rate brachytherapy (HDR-BT) as a salvage therapy option after external beam therapy with or without BT. Emphasis was put on toxicity and 5-year outcome. From 2003 to 2011, 29 patients with local failure after previous radiotherapy for prostate cancer were treated with salvage interstitial HDR-BT. The diagnosis of local recurrence was made on the basis of choline positron emission tomography. Salvage HDR-BT was given in three fractions with a single dose of 10 Gy per fraction and weekly. The target volume covered the peripheral zone of the prostate and the positron emission tomography-positive area. Acute and late toxicities were documented according to common terminology criteria for adverse events (CTCAE v 4.0). Twenty-two patients with minimum followup of 60 months were analyzed. The 5-year overall survival was 95.5% with a disease-specific survival of 100%. The 5-year biochemical control was 45%. Late grade 2 gastrointestinal toxicities were observed in two patients (9%). No grade 3 or higher gastrointestinal late toxicities were observed. Urinary incontinence found in 2 patients (9%) and grade 2 obstruction of urinary tract occurred in one patient (4%). Interstitial HDR-BT was feasible and effective in the treatment of locally recurrent prostate cancer after definitive radiotherapy. The long-term toxicity was low and acceptable. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  8. Three-dimensional simulations of Nova capsule implosion experiments

    SciTech Connect

    Marinak, M.M.; Tipton, R.E.; Landen, O.L.

    1995-11-01

    Capsule implosion experiments carried out on the Nova laser are simulated with the three-dimensional HYDRA radiation hydrodynamics code. Simulations of ordered near single mode perturbations indicate that structures which evolve into round spikes can penetrate farthest into the hot spot. Bubble-shaped perturbations can burn through the capsule shell fastest, however, causing even more damage. Simulations of a capsule with multimode perturbations shows spike amplitudes evolving in good agreement with a saturation model during the deceleration phase. The presence of sizable low mode asymmetry, caused either by drive asymmetry or perturbations in the capsule shell, can dramatically affect the manner in which spikes approach the center of the hot spot. Three-dimensional coupling between the low mode shell perturbations intrinsic to Nova capsules and the drive asymmetry brings the simulated yields into closer agreement with the experimental values.

  9. Comparative Analysis of Whole-Genome Gene Expression Changes in Cultured Human Embryonic Stem Cells in Response to Low, Clinical Diagnostic Relevant, and High Doses of Ionizing Radiation Exposure.

    PubMed

    Sokolov, Mykyta; Nguyen, Van; Neumann, Ronald

    2015-06-30

    The biological effects of low-dose ionizing radiation (LDIR) exposure in humans are not comprehensively understood, generating a high degree of controversy in published literature. The earliest stages of human development are known to be among the most sensitive to stress exposures, especially genotoxic stresses. However, the risks stemming from exposure to LDIR, particularly within the clinical diagnostic relevant dose range, have not been directly evaluated in human embryonic stem cells (hESCs). Here, we describe the dynamics of the whole genome transcriptional responses of different hESC lines to both LDIR and, as a reference, high-dose IR (HDIR). We found that even doses as low as 0.05 Gy could trigger statistically significant transient changes in a rather limited subset of genes in all hESCs lines examined. Gene expression signatures of hESCs exposed to IR appear to be highly dose-, time-, and cell line-dependent. We identified 50 genes constituting consensus gene expression signature as an early response to HDIR across all lines of hESC examined. We observed substantial differences in biological pathways affected by either LDIR or HDIR in hESCs, suggesting that the molecular mechanisms underpinning the responses of hESC may fundamentally differ depending on radiation doses.

  10. Three-dimensional chiral photonic superlattices.

    PubMed

    Thiel, M; Fischer, H; von Freymann, G; Wegener, M

    2010-01-15

    We investigate three-dimensional photonic superlattices composed of polymeric helices in various spatial checkerboard-like arrangements. Depending on the relative phase shift and handedness of the chiral building blocks, different circular-dichroism resonances appear or are suppressed. Samples corresponding to four different configurations are fabricated by direct laser writing. The measured optical transmittance spectra are in good agreement with numerical calculations.

  11. Three-dimensional RF structure calculations

    NASA Astrophysics Data System (ADS)

    Cooper, R. K.; Browman, M. J.; Weiland, T.

    1989-04-01

    The calculation of three-dimensional rf structures is rapidly approaching adolescence, after having been in its infancy for the last four years. This paper will show the kinds of calculations that are currently being performed in the frequency domain and is a companion paper to one in which time-domain calculations are described.