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Sample records for dose affects odontoblast

  1. Fluoride at non-toxic dose affects odontoblast gene expression in vitro

    International Nuclear Information System (INIS)

    Wurtz, Tilmann; Houari, Sophia; Mauro, Nicole; MacDougall, Mary; Peters, Heiko; Berdal, Ariane

    2008-01-01

    Elevated fluoride intake may lead to local tissue disturbances, known as fluorosis. Towards an understanding of this effect, fluoride-induced molecular responses were analyzed in MO6-G3 cultured odontoblasts cells. NaF at 1 mM changed expression of genes implicated in tissue formation and growth, without affecting cell proliferation or inducing stress factor RNAs. Up to 1 mM NaF, DNA accumulation was not inhibited, whereas at 3 mM, cells detached from their support and did not proliferate. Intracellular structures, characterized by EM, were normal up to 1 mM, but at 3 mM, necrotic features were evident. No sign of apoptotic transformation appeared at any NaF concentration. Fluoride-sensitive genes were identified by microarray analysis; expression levels of selected RNAs were determined by conventional and real-time RT-PCR. At 1 mM fluoride, RNAs encoding the extracellular matrix proteins asporin and fibromodulin, and the cell membrane associated proteins periostin and IMT2A were 10-fold reduced. RNA coding for signaling factor TNF-receptor 9 was diminished to one-third, whereas that for the chemokine Scya-5 was enhanced 2.5-fold. These RNAs are present in vivo in tooth forming cells. This was demonstrated by in situ hybridization and RT-PCR on RNA from dissected tissue samples; for the presence and functioning of fibromodulin in dentin matrix, a more comprehensive study has earlier been performed by others [Goldberg, M., Septier, D., Oldberg, A., Young, M.F., Ameye, L.G., 2006. Fibromodulin deficient mice display impaired collagen fibrillogenesis in predentin as well as altered dentin mineralization and enamel formation. J. Histochem. Cytochem. 54, 525-537]. Expression of most other RNA species, in particular of stress factor coding RNAs, was not altered. It was concluded that fluoride could influence the transcription pattern without inducing cell stress or apoptosis. In odontoblasts in vivo, aberrant expression of these fluoride-sensitive genes may impair the

  2. Inhibition of chondroitin sulfate glycosaminoglycans incorporation affected odontoblast differentiation in cultured embryonic mouse molars.

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    Liu, Lipei; Chen, Weiting; Li, Lefeng; Xu, Fangfang; Jiang, Beizhan

    2017-12-01

    Chondroitin sulfate proteoglycan (CSPG) is an important component of extracellular matrix (ECM), it is composed of a core protein and one or more chondroitin sulfate glycosaminoglycan side chains (CS-GAGs). To investigate the roles of its CS-GAGs in dentinogenesis, the mouse mandibular first molar tooth germs at early bell stage were cultivated with or without β-xyloside. As expected, the CS-GAGs were inhibited on their incorporation to CSPGs by β-xyloside, accompanied by the change of morphology of the cultured tooth germs. The histological results and the transmission electron microscopy (TEM) investigation indicated that β-xyloside exhibited obvious inhibiting effects on odontoblasts differentiation compared with the control group. Meanwhile the results of immunohistochemistry, in situ hybridization and quantitative RT-PCR for type I collagen, dentin matrix acidic phosphoprotein 1 and dentin sialophosphoprotein, the products of differentiated odontoblasts, further proved that odontoblasts differentiation was inhibited. Collagen fibers detected in TEM decreased and arranged in disorder as well. Thus we conclude that the inhibition of CS-GAGs incorporation to CSPGs can affect odontoblast differentiation in cultured embryonic mouse molars.

  3. Expression of Vesicular Nucleotide Transporter in Rat Odontoblasts

    International Nuclear Information System (INIS)

    Ikeda, Erina; Goto, Tetsuya; Gunjigake, Kaori; Kuroishi, Kayoko; Ueda, Masae; Kataoka, Shinji; Toyono, Takashi; Nakatomi, Mitsushiro; Seta, Yuji; Kitamura, Chiaki; Nishihara, Tatsuji; Kawamoto, Tatsuo

    2016-01-01

    Several theories have been proposed regarding pain transmission mechanisms in tooth. However, the exact signaling mechanism from odontoblasts to pulp nerves remains to be clarified. Recently, ATP-associated pain transmission has been reported, but it is unclear whether ATP is involved in tooth pain transmission. In the present study, we focused on the vesicular nucleotide transporter (VNUT), a transporter of ATP into vesicles, and examined whether VNUT was involved in ATP release from odontoblasts. We examined the expression of VNUT in rat pulp by RT-PCR and immunostaining. ATP release from cultured odontoblast-like cells with heat stimulation was evaluated using ATP luciferase methods. VNUT was expressed in pulp tissue, and the distribution of VNUT-immunopositive vesicles was confirmed in odontoblasts. In odontoblasts, some VNUT-immunopositive vesicles were colocalized with membrane fusion proteins. Additionally P2X 3 , an ATP receptor, immunopositive axons were distributed between odontoblasts. The ATP release by thermal stimulation from odontoblast-like cells was inhibited by the addition of siRNA for VNUT. These findings suggest that cytosolic ATP is transported by VNUT and that the ATP in the vesicles is then released from odontoblasts to ATP receptors on axons. ATP vesicle transport in odontoblasts seems to be a key mechanism for signal transduction from odontoblasts to axons in the pulp

  4. Intercellular signal communication among odontoblasts and trigeminal ganglion neurons via glutamate.

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    Nishiyama, A; Sato, M; Kimura, M; Katakura, A; Tazaki, M; Shibukawa, Y

    2016-11-01

    Various stimuli to the exposed surface of dentin induce changes in the hydrodynamic force inside the dentinal tubules resulting in dentinal pain. Recent evidences indicate that mechano-sensor channels, such as the transient receptor potential channels, in odontoblasts receive these hydrodynamic forces and trigger the release of ATP to the pulpal neurons, to generate dentinal pain. A recent study, however, has shown that odontoblasts also express glutamate receptors (GluRs). This implies that cells in the dental pulp tissue have the ability to release glutamate, which acts as a functional intercellular mediator to establish inter-odontoblast and odontoblast-trigeminal ganglion (TG) neuron signal communication. To investigate the intercellular signal communication, we applied mechanical stimulation to odontoblasts and measured the intracellular free Ca 2+ concentration ([Ca 2+ ] i ). During mechanical stimulation in the presence of extracellular Ca 2+ , we observed a transient [Ca 2+ ] i increase not only in single stimulated odontoblasts, but also in adjacent odontoblasts. We could not observe these responses in the absence of extracellular Ca 2+ . [Ca 2+ ] i increases in the neighboring odontoblasts during mechanical stimulation of single odontoblasts were inhibited by antagonists of metabotropic glutamate receptors (mGluRs) as well as glutamate-permeable anion channels. In the odontoblast-TG neuron coculture, we observed an increase in [Ca 2+ ] i in the stimulated odontoblasts and TG neurons, in response to direct mechanical stimulation of single odontoblasts. These [Ca 2+ ] i increases in the neighboring TG neurons were inhibited by antagonists for mGluRs. The [Ca 2+ ] i increases in the stimulated odontoblasts were also inhibited by mGluRs antagonists. We further confirmed that the odontoblasts express group I, II, and III mGluRs. However, we could not record any currents evoked from odontoblasts near the mechanically stimulated odontoblast, with or without

  5. Odontoblast layer structure alteration as a response to carious lesions

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    Tetiana Haniastuti

    2011-09-01

    Full Text Available Background: Dental caries is a bacterial disease affecting the hard tissue of the teeth as well as the pulp. The human dental pulp consists of odontoblast which are organized as a densely packed cell layer. Odontoblasts is located at the periphery of the pulp; therefore, they are the first cells encountered by cariogenic bacteria and their products that are represented in the carious lesion. Purpose: This study aimed to elucidate the effect of cariogenic bacteria to odontoblasts of human teeth. Methods: Five intact third molars and 15 third molars with occlusal caries at various stages of decay were extracted because of orthodontic or therapeutic reasons. The tooth specimens were fixed, decalcified with 10% EDTA solution (pH 7.4, and embedded in paraffin. Serial sections of 5 μm thickness were cut and stained with haematoxylin eosin and Gram’s, in addition to nestin immunohistochemistry. The specimens were then examined under light microscopy. Results: In normal teeth, odontoblast layer were aligned along the pulp chamber showing normal morphology of the cells. Slight disorganization of odontoblast layer was seen in the cases of carious lesions confined to enamel. In the cases of carious lesions confined to dentin, odontoblast layer was not observed in the areas subjacent to the lesions, only single cells showing flattened cell morphology were found. Odontoblasts beneath the lesion suffered severe damage and diminished nestin immunoreaction were observed in all cases of carious lesions with pulp exposure. Conclusion: Cariogenic bacteria invasion may damage the odontoblasts by affecting the morphology and vitality of the cells. The severity of the damage of the odontoblasts may increase as the bacterial invasion progresses toward the pulp.Latar belakang: Karies merupakan penyakit yang disebabkan oleh bakteri, yang dapat memengaruhi jaringan keras gigi maupun pulpa. Pada pulpa gigi manusia terdapat sel odontoblas yang tersusun atas lapisan sel

  6. Odontoblasts: Specialized hard-tissue-forming cells in the dentin-pulp complex.

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    Kawashima, Nobuyuki; Okiji, Takashi

    2016-07-01

    Odontoblasts are specialized cells that produce dentin and exhibit unique morphological characteristics; i.e., they extend cytoplasmic processes into dentinal tubules. While osteoblasts, which are typical hard-tissue-forming cells, are generated from mesenchymal stem cells during normal and pathological bone metabolism, the induction of odontoblasts only occurs once during tooth development, and odontoblasts survive throughout the lives of healthy teeth. During the differentiation of odontoblasts, signaling molecules from the inner enamel epithelium are considered necessary for the differentiation of odontoblast precursors, i.e., peripheral dental papilla cells. If odontoblasts are destroyed by severe external stimuli, such as deep caries, the differentiation of dental pulp stem cells into odontoblast-like cells is induced. Various bioactive molecules, such as non-collagenous proteins, might be involved in this process, although the precise mechanisms responsible for odontoblast differentiation have not been fully elucidated. Recently, our knowledge about the other functional activities of odontoblasts (apart from dentin formation) has increased. For example, it has been suggested that odontoblasts might act as nociceptive receptors, and surveillance cells that detect the invasion of exogenous pathogens. The regeneration of the dentin-pulp complex has recently gained much attention as a promising future treatment modality that could increase the longevity of pulpless teeth. Finally, congenital dentin anomalies, which are concerned with the disturbance of odontoblast functions, are summarized. © 2016 Japanese Teratology Society.

  7. Identification of Secretory Odontoblasts Using DMP1-GFP Transgenic Mice

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    Balic, Anamaria; Mina, Mina

    2011-01-01

    Terminal differentiation of odontoblasts from dental papilla is a long process involving several intermediate steps and changes in the transcriptional profile and expression of proteins secreted by cells in the odontoblast lineage. Transgenic mouse lines in which GFP expression is under the control of tissue-and stage specific promoters have provided powerful experimental tools for identification and isolation of cells at specific stages of differentiation along a lineage. Our previous studies showed utilization of pOBCol3.6GFP and pOBCol2.3GFP animals for identification of odontoblasts at early and late stages of polarization respectively. In the present study we used the DMP1-GFP transgenic animal as an experimental model to examine its expression during the differentiation of odontoblasts from progenitor cells in vivo and in vitro. Our observations showed that DMP1-GFP transgene is first activated in secretory/functional odontoblasts engaged in secretion of predentin and then transiently expressed at high levels in newly differentiated odontoblasts. Expression of DMP1-GFP was down-regulated in highly differentiated odontoblasts. The temporal and spatial pattern of expression of DMP1-GFP transgene closely mimics the expression of endogenous DMP1. This transgenic animal will facilitate studies of gene expression and biological functions in secretory/functional odontoblasts. PMID:21172466

  8. Intercellular odontoblast communication via ATP mediated by pannexin-1 channel and phospholipase C-coupled receptor activation.

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    Masaki eSato

    2015-11-01

    Full Text Available Extracellular ATP released via pannexin-1 channels, in response to the activation of mechanosensitive-TRP channels during odontoblast mechanical stimulation, mediates intercellular communication among odontoblasts in dental pulp slice preparation dissected form rat incisor. Recently, odontoblast cell lines, such as mouse odontoblast lineage cells, have been widely used to investigate physiological/pathological cellular functions. To clarify whether the odontoblast cell lines also communicate with each other by diffusible chemical substance(s, we investigated the chemical intercellular communication among cells from mouse odontoblast cell lines following mechanical stimulation. A single cell was stimulated using a glass pipette filled with standard extracellular solution. We measured intracellular free Ca2+ concentration ([Ca2+]i by fura-2 in stimulated cells, as well as in cells located nearby. Direct mechanical stimulation to a single odontoblast increased [Ca2+]i, which showed sensitivity to capsazepine. In addition, we observed increases in [Ca2+]i not only in the mechanically stimulated odontoblast, but also in nearby odontoblasts. We could observe mechanical stimulation-induced increase in [Ca2+]i in a stimulated human embryo kidney (HEK 293 cell, but not in nearby HEK293 cells. The increase in [Ca2+]i in nearby odontoblasts, but not in the stimulated odontoblast, was inhibited by adenosine triphosphate (ATP release channel (pannexin-1 inhibitor in a concentration- and spatial-dependent manner. Moreover, in the presence of phospholipase C (PLC inhibitor, the increase in [Ca2+]i in nearby odontoblasts, following mechanical stimulation of a single odontoblast, was abolished. We could record some inward currents evoked from odontoblasts near the stimulated odontoblast, but the currents were observed in only 4.8% of the recorded odontoblasts. The results of this study showed that ATP is released via pannexin-1, from a mechanically stimulated

  9. Expression, purification, and characterization of a dentin phosphoprotein produced by Escherichia coli, and its odontoblastic differentiation effects on human dental pulp cells.

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    Yun, Ye-Rang; Jeon, Eunyi; Lee, Sujin; Kang, Wonmo; Kim, Sang-Gi; Kim, Hae-Won; Suh, Chang Kook; Jang, Jun-Hyeog

    2012-08-01

    To investigate the functions of recombinant human dentin phosphoprotein (rhDPP), we examined cell adhesion, viability and the odontoblastic differentiation activity of human dental pulp cells (hDPCs). Firstly, rhDPP was constructed using pBAD-HisA plasmid in Escherichia coli. Cell adhesion and viability of hDPCs by rhDPP was examined using a crystal violet assay and a MTT assay, ALP, mineralization activity and odontoblastic differentiation-related mRNA levels of hDPCs were measured to elucidate the odontoblastic differentiation effect of rhDPP on hDPCs. Initially, rhDPP significantly and dose-dependently increased hDPCs adhesion versus the untreated control (p < 0.05). Cell viability was also significantly increased by rhDPP at 5 days (p < 0.001). Furthermore, the odontoblastic differentiation effect of rhDPP was verified by measuring ALP activity, mineralization activity and the mRNA levels of odontoblastic differentiation markers. Taken together, rhDPP is expected to play an important role on hDPCs, thereby suggesting its potential use for tooth repair and regeneration.

  10. The dynamics of TGF-β in dental pulp, odontoblasts and dentin.

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    Niwa, Takahiko; Yamakoshi, Yasuo; Yamazaki, Hajime; Karakida, Takeo; Chiba, Risako; Hu, Jan C-C; Nagano, Takatoshi; Yamamoto, Ryuji; Simmer, James P; Margolis, Henry C; Gomi, Kazuhiro

    2018-03-13

    Transforming growth factor-beta (TGF-β) is critical for cell proliferation and differentiation in dental pulp. Here, we show the dynamic mechanisms of TGF-β in porcine dental pulp, odontoblasts and dentin. The mRNA of latent TGF-β1 and TGF-β3 is predominantly expressed in odontoblasts, whereas the mRNA expression level of latent TGF-β2 is high in dental pulp. TGF-β1 is a major isoform of TGF-β, and latent TGF-β1, synthesized in dental pulp, is primarily activated by matrix metalloproteinase 11 (MMP11). Activated TGF-β1 enhances the mRNA expression levels of MMP20 and full-length dentin sialophosphoprotein (DSPP) in dental pulp cells, coinciding with the induction of odontoblast differentiation. Latent TGF-β1 synthesized in odontoblasts is primarily activated by MMP2 and MMP20 in both odontoblasts and dentin. The activity level of TGF-β1 was reduced in the dentin of MMP20 null mice, although the amount of latent TGF-β1 expression did not change between wild-type and MMP20 null mice. TGF-β1 activity was reduced with the degradation of DSPP-derived proteins that occurs with ageing. We propose that to exert its multiple biological functions, TGF-β1 is involved in a complicated dynamic interaction with matrix metalloproteinases (MMPs) and/or DSPP-derived proteins present in dental pulp, odontoblasts and dentin.

  11. Mouse ES cells have a potential to differentiate into odontoblast-like cells using hanging drop method.

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    Kawai, R; Ozeki, N; Yamaguchi, H; Tanaka, T; Nakata, K; Mogi, M; Nakamura, H

    2014-05-01

    We examined whether mouse embryonic stem (ES) cells can differentiate into odontoblast-like cells without epithelial-mesenchymal interaction. Cells were cultured by the 'hanging drop' method using a collagen type-I scaffold (CS) combined with bone morphogenetic protein (BMP)-4 (CS/BMP-4). Expression of odontoblast-related mRNA and protein, and cell proliferation were performed by reverse transcription-polymerase chain reaction (RT-PCR), immunofluorescence staining and WST-1 assay, respectively. Cells potently expressed odontoblast-related cell marker mRNAs following induction of odontoblastic differentiation. Dentin sialophosphoprotein, a marker of mature odontoblasts, was strongly expressed in differentiated ES cells. The cells also acquired an odontoblast-like functional phenotype, as evidenced by the appearance of alkaline phosphatase activity and calcification. The cell-surface expression of α2, α6, αV and αVβ3 integrin proteins was rapidly upregulated in differentiated cells. Finally, anti-α2 integrin antibody suppressed the expression of odontoblastic markers in cells grown using this culture system, suggesting that α2 integrin expression in ES cells triggers their differentiation into odontoblast-like cells. Mouse ES cells cultured by the 'hanging drop' method are able to differentiate into cells with odontoblast-specific physiological functions and cell-surface integrin protein expression. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Polyphosphate induces matrix metalloproteinase-3-mediated proliferation of odontoblast-like cells derived from induced pluripotent stem cells

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    Ozeki, Nobuaki; Hase, Naoko; Yamaguchi, Hideyuki; Hiyama, Taiki; Kawai, Rie [Department of Endodontics, School of Dentistry, Aichi Gakuin University, 2-11 Suemori-dori, Chikusa-ku, Nagoya, Aichi 464-8651 (Japan); Kondo, Ayami [Department of Medicinal Biochemistry, School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto, Chikusa-ku, Nagoya 464-8650 (Japan); Nakata, Kazuhiko [Department of Endodontics, School of Dentistry, Aichi Gakuin University, 2-11 Suemori-dori, Chikusa-ku, Nagoya, Aichi 464-8651 (Japan); Mogi, Makio, E-mail: makio@dpc.agu.ac.jp [Department of Medicinal Biochemistry, School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto, Chikusa-ku, Nagoya 464-8650 (Japan)

    2015-05-01

    Inorganic polyphosphate [Poly(P)] may represent a physiological source of phosphate and has the ability to induce bone differentiation in osteoblasts. We previously reported that cytokine-induced matrix metalloproteinase (MMP)-3 accelerates the proliferation of purified odontoblast-like cells. In this study, MMP-3 small interfering RNA (siRNA) was transfected into odontoblast-like cells derived from induced pluripotent stem cells to investigate whether MMP-3 activity is induced by Poly(P) and/or is associated with cell proliferation and differentiation into odontoblast-like cells. Treatment with Poly(P) led to an increase in both cell proliferation and additional odontoblastic differentiation. Poly(P)-treated cells showed a small but significant increase in dentin sialophosphoprotein (DSPP) and dentin matrix protein-1 (DMP-1) mRNA expression, which are markers of mature odontoblasts. The cells also acquired additional odontoblast-specific properties including adoption of an odontoblastic phenotype typified by high alkaline phosphatase (ALP) activity and a calcification capacity. In addition, Poly(P) induced expression of MMP-3 mRNA and protein, and increased MMP-3 activity. MMP-3 siRNA-mediated disruption of the expression of these effectors potently suppressed the expression of odontoblastic biomarkers ALP, DSPP, and DMP-1, and blocked calcification. Interestingly, upon siRNA-mediated silencing of MMP-3, we noted a potent and significant decrease in cell proliferation. Using specific siRNAs, we revealed that a unique signaling cascade, Poly(P)→MMP-3→DSPP and/or DMP-1, was intimately involved in the proliferation of odontoblast-like cells. - Highlights: • Polyphosphate increases proliferation of iPS cell-derived odontoblast-like cells. • Polyphosphate-induced MMP-3 results in an increase of cell proliferation. • Induced cell proliferation involves MMP-3, DSPP, and/or DMP-1 sequentially. • Induced MMP-3 also results in an increase of odontoblastic

  13. Odontoblast-Like Cells Differentiated from Dental Pulp Stem Cells Retain Their Phenotype after Subcultivation

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    Paula A. Baldión

    2018-01-01

    Full Text Available Odontoblasts, the main cell type in teeth pulp tissue, are not cultivable and they are responsible for the first line of response after dental restauration. Studies on dental materials cytotoxicity and odontoblast cells physiology require large quantity of homogenous cells retaining most of the phenotype characteristics. Odontoblast-like cells (OLC were differentiated from human dental pulp stem cells using differentiation medium (containing TGF-β1, and OLC expanded after trypsinization (EXP-21 were evaluated and compared. Despite a slower cell growth curve, EXP-21 cells express similarly the odontoblast markers dentinal sialophosphoprotein and dentin matrix protein-1 concomitantly with RUNX2 transcripts and low alkaline phosphatase activity as expected. Both OLC and EXP-21 cells showed similar mineral deposition activity evidenced by alizarin red and von Kossa staining. These results pointed out minor changes in phenotype of subcultured EXP-21 regarding the primarily differentiated OLC, making the subcultivation of these cells a useful strategy to obtain odontoblasts for biocompatibility or cell physiology studies in dentistry.

  14. Functional expression of TRPM8 and TRPA1 channels in rat odontoblasts.

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    Maki Tsumura

    Full Text Available Odontoblasts produce dentin during development, throughout life, and in response to pathological conditions by sensing stimulation of exposed dentin. The functional properties and localization patterns of transient receptor potential (TRP melastatin subfamily member 8 (TRPM8 and ankyrin subfamily member 1 (TRPA1 channels in odontoblasts remain to be clarified. We investigated the localization and the pharmacological, biophysical, and mechano-sensitive properties of TRPM8 and TRPA1 channels in rat odontoblasts. Menthol and icilin increased the intracellular free Ca(2+ concentration ([Ca(2+]i. Icilin-, WS3-, or WS12-induced [Ca(2+]i increases were inhibited by capsazepine or 5-benzyloxytriptamine. The increase in [Ca(2+]i elicited by allyl isothiocyanate (AITC was inhibited by HC030031. WS12 and AITC exerted a desensitizing effect on [Ca(2+]i increase. Low-temperature stimuli elicited [Ca(2+]i increases that are sensitive to both 5-benzyloxytriptamine and HC030031. Hypotonic stimulation-induced membrane stretch increased [Ca(2+]i; HC030031 but not 5-benzyloxytriptamine inhibited the effect. The results suggest that TRPM8 channels in rat odontoblasts play a role in detecting low-temperature stimulation of the dentin surface and that TRPA1 channels are involved in sensing membrane stretching and low-temperature stimulation. The results also indicate that odontoblasts act as mechanical and thermal receptor cells, detecting the stimulation of exposed dentin to drive multiple cellular functions, such as sensory transduction.

  15. The expressions of NF-kb and TGFb-1 on odontoblast-like cells of human dental pulp injected with propolis extracts

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    Ira Widjiastuti

    2014-03-01

    Full Text Available Background: Propolis is known to have beneficial effects, namely anti- bacterial, anti-viral, anti-inflammatory, antioxidant, and immunomodulatory. Propolis extracts with anti-inflammatory properties are expected to be useful in treating inflamed pulp tissue with a diagnosis of reversible pulpitis. The inflammation of pulp tissue is caused by bacteria, namely Lactobacillus acidophilus. This research used odontoblast like cells derived from pulp tissue of human third molars. Odontoblast like cells exposed to Lactobacillus achidophilus were used as a model of proinflammatory cytokine signaling. This research examined the effects of propolis extracts on odontoblast like cells exposed to Lactobacillus acidophilus. Purpose: This research was aimed to determine the effectiveness of propolis extracts on the activities of odontoblast-like cells exposed to Lactobacillus acidophillus by measuring the expressions of NFkb and TGF- b1. Methods: First, pulp odontoblast cultures were derived from human dental pulp tissues of impacted third molars removed by using digestion method. Next, odontoblast-like cells exposed to inactive Lactobacillus acidophilus bacteria were given propolis extract. Finally, the activities of odontoblast-like cells were monitored by measuring the expressions of NF-kb and TGFb-1 with immunocytochemistry technique. Results: A decline NF-kb expression and on increase of TGFb-1 expression on odontoblast like cells exposed to inactive Lactobacillus acidophilus. Conclusion: Propolis extracts inhibit the expression of NF-kb, and increase the expression of TGF-b1 in pulp odontoblast-like cells exposed to inactive Lactobacillus acidophillus.Latar belakang: Propolis dilaporkan mempunyai efek menguntungkan yaitu bersifat anti bakteri, anti virus, anti inflamasi, anti oksidan, dan imunomodulator. Ekstrak propolis dengan sifat anti inflamasi diharapkan bermanfaat untuk mengobati jaringan pulpa yang mengalami inflamasi dengan diagnosis pulpitis

  16. A quantitative light microscopic study of the odontoblast and subodontoblastic reactions to active and arrested enamel caries without cavitation

    DEFF Research Database (Denmark)

    Bjørndal, L.; Darvann, T.A.; Thylstrup, Anders

    1998-01-01

    Carious lesions, Computerized histomorphology, Dental pulp, Dentine, Enamel, Microradiography, Odontoblast......Carious lesions, Computerized histomorphology, Dental pulp, Dentine, Enamel, Microradiography, Odontoblast...

  17. Functional Roles of NOD1 in Odontoblasts on Dental Pulp Innate Immunity

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    Yuki Hosokawa

    2016-01-01

    Full Text Available Caries-related pathogens are first recognized by odontoblasts and induce inflammatory events that develop to pulpitis. Generally, initial sensing of microbial pathogens is mediated by pattern recognition receptors, such as Toll-like receptor and nucleotide-binding oligomerization domain (NOD; however, little is known about NODs in odontoblasts. In this study, the levels of NODs expressed in rat odontoblastic cell line, KN-3, were assessed by flow cytometry and the levels of chemokines in NOD-specific ligand-stimulated KN-3 cells were analyzed by real-time PCR and ELISA. The signal transduction pathway activated with NOD-specific ligand was assessed by blocking assay with specific inhibitors and reporter assay. In KN-3 cells, the expression level of NOD1 was stronger than that of NOD2 and the production of chemokines, such as CINC-1, CINC-2, CCL20, and MCP-1, was upregulated by stimulation with NOD1-specific ligand, but not with NOD2-specific ligand. CINC-2 and CCL20 production by stimulation with NOD1-specific ligand was reduced by p38 MAPK and AP-1 signaling inhibitors. Furthermore, the reporter assay demonstrated AP-1 activation in NOD1-specific ligand-stimulated KN-3 cells. These findings indicated that NOD1 expressed in odontoblasts functions to upregulate the chemokines expression via p38-AP-1 signaling pathway and suggested that NOD1 may play important roles in the initiation and progression of pulpitis.

  18. Functional Roles of NOD1 in Odontoblasts on Dental Pulp Innate Immunity.

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    Hosokawa, Yuki; Hirao, Kouji; Yumoto, Hiromichi; Washio, Ayako; Nakanishi, Tadashi; Takegawa, Daisuke; Kitamura, Chiaki; Matsuo, Takashi

    2016-01-01

    Caries-related pathogens are first recognized by odontoblasts and induce inflammatory events that develop to pulpitis. Generally, initial sensing of microbial pathogens is mediated by pattern recognition receptors, such as Toll-like receptor and nucleotide-binding oligomerization domain (NOD); however, little is known about NODs in odontoblasts. In this study, the levels of NODs expressed in rat odontoblastic cell line, KN-3, were assessed by flow cytometry and the levels of chemokines in NOD-specific ligand-stimulated KN-3 cells were analyzed by real-time PCR and ELISA. The signal transduction pathway activated with NOD-specific ligand was assessed by blocking assay with specific inhibitors and reporter assay. In KN-3 cells, the expression level of NOD1 was stronger than that of NOD2 and the production of chemokines, such as CINC-1, CINC-2, CCL20, and MCP-1, was upregulated by stimulation with NOD1-specific ligand, but not with NOD2-specific ligand. CINC-2 and CCL20 production by stimulation with NOD1-specific ligand was reduced by p38 MAPK and AP-1 signaling inhibitors. Furthermore, the reporter assay demonstrated AP-1 activation in NOD1-specific ligand-stimulated KN-3 cells. These findings indicated that NOD1 expressed in odontoblasts functions to upregulate the chemokines expression via p38-AP-1 signaling pathway and suggested that NOD1 may play important roles in the initiation and progression of pulpitis.

  19. Mouse-induced pluripotent stem cells differentiate into odontoblast-like cells with induction of altered adhesive and migratory phenotype of integrin.

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    Nobuaki Ozeki

    Full Text Available Methods for differentiating induced pluripotent stem (iPS cells into odontoblasts generally require epithelial-mesenchymal interactions. Here, we sought to characterize the cells produced by a 'hanging drop' technique for differentiating mouse iPS cells into odontoblast-like cells that requires no such interaction. Cells were cultured by the hanging drop method on a collagen type-I (Col-I scaffold (CS combined with bone morphogenetic protein (BMP-4 (CS/BMP-4 without an epithelial-mesenchymal interaction. We evaluated the expression of odontoblast-related mRNA and protein, and the proliferation rate of these cells using reverse-transcription polymerase chain reaction, immunofluorescence staining, and BrdU cell proliferation enzyme-linked immunosorbent assay, respectively. The differentiated cells strongly expressed the mRNA for dentin sialophosphoprotein (DSPP and dentin matrix protein-1 (Dmp-1, which are markers of mature odontoblasts. Osteopontin and osteocalcin were not expressed in the differentiated cells, demonstrating that the differentiated iPS cells bore little resemblance to osteoblasts. Instead, they acquired odontoblast-specific properties, including the adoption of an odontoblastic phenotype, typified by high alkaline phosphatase (ALP activity and calcification capacity. The cell-surface expression of proteins such as integrins α2, α6, αV and αVβ3 was rapidly up-regulated. Interestingly, antibodies and siRNAs against integrin α2 suppressed the expression of DSPP and Dmp-1, reduced the activity of ALP and blocked calcification, suggesting that integrin α2 in iPS cells mediates their differentiation into odontoblast-like cells. The adhesion of these cells to fibronectin and Col-I, and their migration on these substrata, was significantly increased following differentiation into odontoblast-like cells. Thus, we have demonstrated that integrin α2 is involved in the differentiation of mouse iPS cells into odontoblast-like cells

  20. NRP1 Accelerates Odontoblast Differentiation of Dental Pulp Stem Cells Through Classical Wnt/β-Catenin Signaling.

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    Song, Yihua; Liu, Xiaojuan; Feng, Xingmei; Gu, Zhifeng; Gu, Yongchun; Lian, Min; Xiao, Jingwen; Cao, Peipei; Zheng, Ke; Gu, Xiaobing; Li, Dongping; He, Ping; Wang, Chenfei

    2017-10-01

    Neuropilin-1 (NRP1) is one of the members of neuropilin family. It can combine with disparate ligands involved in regulating cell proliferation, apoptosis, and differentiation. The binding of NRP1 to Sema3A stimulates osteoblast differentiation through the classical Wnt/β-catenin pathway. However, the functions of NRP1 in dental pulp stem cells (DPSCs) are not clear. The aim of our study was to investigate how NRP1 controlled odontoblast differentiation in DPSCs and clarified the underlying mechanisms. NRP1 expression was increased in time-dependent manner along with cell odontoblast differentiation. Overexpression of NRP1 upregulated dentin matrix protein-1, dentin sialophosphoprotein, alkaline phosphatase protein level, and mineralization in DPSCs, while knockdown of NRP1 induced the opposite effects. SiNRP1 similar to DKK1 availably blocked classical Wnt/β-catenin signaling and odontoblast differentiation. In summary, NRP1, as a promoter of odontoblast differentiation, regulates DPSCs via the classical Wnt/β-catenin pathway.

  1. In vitro effect of low-level laser on odontoblast-like cells

    International Nuclear Information System (INIS)

    Oliveira, C F; Hebling, J; De Souza Costa, C A; Basso, F G; Lins, E C; Kurachi, C; Bagnato, V S

    2011-01-01

    The aim of this study was to evaluate the metabolism of odontoblast-like MDPC-23 cells subjected to direct LLL irradiation. The cells were seeded (20,000 cells/well) in 24-well plates and incubated for 24 hours at 37deg C. After this period, the culture medium (DMEM) was replaced by fresh DMEM supplemented with 2 or 5% (stress induction by nutritional deficit) or 10% fetal bovine serum (FBS). The cells were exposed to laser doses of 2, 4, 10, 15 and 25 J/cm 2 from a near infrared InGaAsP diode laser prototype (LASERTable; 780±3 nm, 40 mW). One control group (sham irradiation) was established for each experimental condition (laser dose x FBS supplementation). Three and 72 hours after the last irradiation, cells were analyzed with respect to metabolism, morphology, total protein expression and alkaline phosphatase (ALP) activity. Higher metabolism and total protein expression were observed 72 hours after the last irradiation at the doses of 15 and 25 J/cm 2 (Mann-Whitney; p 2 . For the dose of 25 J/cm 2 , the highest ALP activity was observed with 10% FBS. It was concluded that the LLLT parameters used in this study stimulated the metabolic activity of the MDPC-23 cells, especially at the doses of 15 and 25 J/cm 2

  2. Unique proliferation response in odontoblastic cells derived from human skeletal muscle stem cells by cytokine-induced matrix metalloproteinase-3

    International Nuclear Information System (INIS)

    Ozeki, Nobuaki; Hase, Naoko; Kawai, Rie; Yamaguchi, Hideyuki; Hiyama, Taiki; Kondo, Ayami; Nakata, Kazuhiko; Mogi, Makio

    2015-01-01

    A pro-inflammatory cytokine mixture (CM: interleukin (IL)-1β, tumor necrosis factor-α and interferon-γ) and IL-1β-induced matrix metalloproteinase (MMP)-3 activity have been shown to increase the proliferation of rat dental pulp cells and murine stem cell-derived odontoblast-like cells. This suggests that MMP-3 may regulate wound healing and regeneration in the odontoblast-rich dental pulp. Here, we determined whether these results can be extrapolated to human dental pulp by investigating the effects of CM-induced MMP-3 up-regulation on the proliferation and apoptosis of purified odontoblast-like cells derived from human skeletal muscle stem cells. We used siRNA to specifically reduce MMP-3 expression. We found that CM treatment increased MMP-3 mRNA and protein levels as well as MMP-3 activity. Cell proliferation was also markedly increased, with no changes in apoptosis, upon treatment with CM and following the application of exogenous MMP-3. Endogenous tissue inhibitors of metalloproteinases were constitutively expressed during all experiments and unaffected by MMP-3. Although treatment with MMP-3 siRNA suppressed cell proliferation, it also unexpectedly increased apoptosis. This siRNA-mediated increase in apoptosis could be reversed by exogenous MMP-3. These results demonstrate that cytokine-induced MMP-3 activity regulates cell proliferation and suppresses apoptosis in human odontoblast-like cells. - Highlights: • Pro-inflammatory cytokines induce MMP-3 activity in human odontoblast-like cells. • Increased MMP-3 activity can promote cell proliferation in odontoblasts. • Specific loss of MMP-3 increases apoptosis in odontoblasts. • MMP-3 has potential as a promising new target for pupal repair and regeneration

  3. Unique proliferation response in odontoblastic cells derived from human skeletal muscle stem cells by cytokine-induced matrix metalloproteinase-3

    Energy Technology Data Exchange (ETDEWEB)

    Ozeki, Nobuaki; Hase, Naoko; Kawai, Rie; Yamaguchi, Hideyuki; Hiyama, Taiki [Department of Endodontics, School of Dentistry, Aichi Gakuin University, 2-11 Suemori-dori, Chikusa-ku, Nagoya 464-8651, Aichi (Japan); Kondo, Ayami [Department of Medicinal Biochemistry, School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto, Chikusa-ku, Nagoya 464-8650 (Japan); Nakata, Kazuhiko [Department of Endodontics, School of Dentistry, Aichi Gakuin University, 2-11 Suemori-dori, Chikusa-ku, Nagoya 464-8651, Aichi (Japan); Mogi, Makio, E-mail: makio@dpc.agu.ac.jp [Department of Medicinal Biochemistry, School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto, Chikusa-ku, Nagoya 464-8650 (Japan)

    2015-02-01

    A pro-inflammatory cytokine mixture (CM: interleukin (IL)-1β, tumor necrosis factor-α and interferon-γ) and IL-1β-induced matrix metalloproteinase (MMP)-3 activity have been shown to increase the proliferation of rat dental pulp cells and murine stem cell-derived odontoblast-like cells. This suggests that MMP-3 may regulate wound healing and regeneration in the odontoblast-rich dental pulp. Here, we determined whether these results can be extrapolated to human dental pulp by investigating the effects of CM-induced MMP-3 up-regulation on the proliferation and apoptosis of purified odontoblast-like cells derived from human skeletal muscle stem cells. We used siRNA to specifically reduce MMP-3 expression. We found that CM treatment increased MMP-3 mRNA and protein levels as well as MMP-3 activity. Cell proliferation was also markedly increased, with no changes in apoptosis, upon treatment with CM and following the application of exogenous MMP-3. Endogenous tissue inhibitors of metalloproteinases were constitutively expressed during all experiments and unaffected by MMP-3. Although treatment with MMP-3 siRNA suppressed cell proliferation, it also unexpectedly increased apoptosis. This siRNA-mediated increase in apoptosis could be reversed by exogenous MMP-3. These results demonstrate that cytokine-induced MMP-3 activity regulates cell proliferation and suppresses apoptosis in human odontoblast-like cells. - Highlights: • Pro-inflammatory cytokines induce MMP-3 activity in human odontoblast-like cells. • Increased MMP-3 activity can promote cell proliferation in odontoblasts. • Specific loss of MMP-3 increases apoptosis in odontoblasts. • MMP-3 has potential as a promising new target for pupal repair and regeneration.

  4. Transforming growth factor-β-induced gene product-h3 inhibits odontoblastic differentiation of dental pulp cells.

    Science.gov (United States)

    Serita, Suguru; Tomokiyo, Atsushi; Hasegawa, Daigaku; Hamano, Sayuri; Sugii, Hideki; Yoshida, Shinichiro; Mizumachi, Hiroyuki; Mitarai, Hiromi; Monnouchi, Satoshi; Wada, Naohisa; Maeda, Hidefumi

    2017-06-01

    The aim of this study was to investigate transforming growth factor-β-induced gene product-h3 (βig-h3) expression in dental pulp tissue and its effects on odontoblastic differentiation of dental pulp cells (DPCs). A rat direct pulp capping model was prepared using perforated rat upper first molars capped with mineral trioxide aggregate cement. Human DPCs (HDPCs) were isolated from extracted teeth. βig-h3 expression in rat dental pulp tissue and HDPCs was assessed by immunostaining. Mineralization of HDPCs was assessed by Alizarin red-S staining. Odontoblast-related gene expression in HDPCs was analyzed by quantitative RT-PCR. Expression of βig-h3 was detected in rat dental pulp tissue, and attenuated by direct pulp capping, while expression of interleukin-1β and tumor necrosis factor-α was increased in exposed pulp tissue. βig-h3 expression was also detected in HDPCs, with reduced expression during odontoblastic differentiation. The above cytokines reduced βig-h3 expression in HDPCs, and promoted their mineralization. Recombinant βig-h3 inhibited the expression of odontoblast-related genes and mineralization of HDPCs, while knockdown of βig-h3 gene expression promoted the expression of odontoblast-related genes in HDPCs. The present findings suggest that βig-h3 in DPCs may be involved in reparative dentin formation and that its expression is likely to negatively regulate this process. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Interleukin-1β-induced autophagy-related gene 5 regulates proliferation of embryonic stem cell-derived odontoblastic cells.

    Directory of Open Access Journals (Sweden)

    Nobuaki Ozeki

    Full Text Available We previously established a method for the differentiation of induced pluripotent stem cells and embryonic stem cells into α2 integrin-positive odontoblast-like cells. We also reported that Wnt5 in response to interleukin (IL-1β induces matrix metalloproteinase (MMP-3-regulated cell proliferation in these cells. Our findings suggest that MMP-3 plays a potentially unique physiological role in the generation of odontoblast-like cells under an inflammatory state. Here, we examined whether up-regulation of autophagy-related gene (Atg 5 by IL-1β was mediated by Wnt5 signaling, thus leading to increased proliferation of odontoblast-like cells. IL-1β increased the mRNA and protein levels of Atg5, microtubule-associated protein 1 light chain (LC3, a mammalian homolog of yeast Atg8 and Atg12. Treatment with siRNAs against Atg5, but not LC3 and Atg12, suppressed the IL-1β-induced increase in MMP-3 expression and cell proliferation. Our siRNA analyses combined with western blot analysis revealed a unique sequential cascade involving Atg5, Wnt5a and MMP-3, which resulted in the potent increase in odontoblastic cell proliferation. These results demonstrate the unique involvement of Atg5 in IL-1β-induced proliferation of embryonic stem cell-derived odontoblast-like cells.

  6. Activation of Mechanosensitive Transient Receptor Potential/Piezo Channels in Odontoblasts Generates Action Potentials in Cocultured Isolectin B4-negative Medium-sized Trigeminal Ganglion Neurons.

    Science.gov (United States)

    Sato, Masaki; Ogura, Kazuhiro; Kimura, Maki; Nishi, Koichi; Ando, Masayuki; Tazaki, Masakazu; Shibukawa, Yoshiyuki

    2018-04-27

    Various stimuli to the dentin surface elicit dentinal pain by inducing dentinal fluid movement causing cellular deformation in odontoblasts. Although odontoblasts detect deformation by the activation of mechanosensitive ionic channels, it is still unclear whether odontoblasts are capable of establishing neurotransmission with myelinated A delta (Aδ) neurons. Additionally, it is still unclear whether these neurons evoke action potentials by neurotransmitters from odontoblasts to mediate sensory transduction in dentin. Thus, we investigated evoked inward currents and evoked action potentials form trigeminal ganglion (TG) neurons after odontoblast mechanical stimulation. We used patch clamp recordings to identify electrophysiological properties and record evoked responses in TG neurons. We classified TG cells into small-sized and medium-sized neurons. In both types of neurons, we observed voltage-dependent inward currents. The currents from medium-sized neurons showed fast inactivation kinetics. When mechanical stimuli were applied to odontoblasts, evoked inward currents were recorded from medium-sized neurons. Antagonists for the ionotropic adenosine triphosphate receptor (P2X 3 ), transient receptor potential channel subfamilies, and Piezo1 channel significantly inhibited these inward currents. Mechanical stimulation to odontoblasts also generated action potentials in the isolectin B 4 -negative medium-sized neurons. Action potentials in these isolectin B 4 -negative medium-sized neurons showed a short duration. Overall, electrophysiological properties of neurons indicate that the TG neurons with recorded evoked responses after odontoblast mechanical stimulation were myelinated Aδ neurons. Odontoblasts established neurotransmission with myelinated Aδ neurons via P2X 3 receptor activation. The results also indicated that mechanosensitive TRP/Piezo1 channels were functionally expressed in odontoblasts. The activation of P2X 3 receptors induced an action potential

  7. α2 Integrin, extracellular matrix metalloproteinase inducer, and matrix metalloproteinase-3 act sequentially to induce differentiation of mouse embryonic stem cells into odontoblast-like cells

    International Nuclear Information System (INIS)

    Ozeki, Nobuaki; Kawai, Rie; Hase, Naoko; Hiyama, Taiki; Yamaguchi, Hideyuki; Kondo, Ayami; Nakata, Kazuhiko; Mogi, Makio

    2015-01-01

    We previously reported that interleukin 1β acts via matrix metalloproteinase (MMP)-3 to regulate cell proliferation and suppress apoptosis in α2 integrin-positive odontoblast-like cells differentiated from mouse embryonic stem (ES) cells. Here we characterize the signal cascade underpinning odontoblastic differentiation in mouse ES cells. The expression of α2 integrin, extracellular matrix metalloproteinase inducer (Emmprin), and MMP-3 mRNA and protein were all potently increased during odontoblastic differentiation. Small interfering RNA (siRNA) disruption of the expression of these effectors potently suppressed the expression of the odontoblastic biomarkers dentin sialophosphoprotein, dentin matrix protein-1 and alkaline phosphatase, and blocked odontoblast calcification. Our siRNA, western blot and blocking antibody analyses revealed a unique sequential cascade involving α2 integrin, Emmprin and MMP-3 that drives ES cell differentiation into odontoblasts. This cascade requires the interaction between α2 integrin and Emmprin and is potentiated by exogenous MMP-3. Finally, although odontoblast-like cells potently express α2, α6, αV, β1, and β3, integrins, we confirmed that β1 integrin acts as the trigger for ES cell differentiation, apparently in complex with α2 integrin. These results demonstrate a unique and unanticipated role for an α2 integrin-, Emmprin-, and MMP-3-mediated signaling cascade in driving mouse ES cell differentiation into odontoblast-like cells. - Highlights: • Odontoblast differentiation requires activation of α2 integrin, Emmprin and MMP-3. • α2 integrin, Emmprin and MMP-3 form a sequential signaling cascade. • β1 integrin acts a specific trigger for odontoblast differentiation. • The role of these effectors is highly novel and unanticipated

  8. α2 Integrin, extracellular matrix metalloproteinase inducer, and matrix metalloproteinase-3 act sequentially to induce differentiation of mouse embryonic stem cells into odontoblast-like cells

    Energy Technology Data Exchange (ETDEWEB)

    Ozeki, Nobuaki; Kawai, Rie; Hase, Naoko; Hiyama, Taiki; Yamaguchi, Hideyuki [Department of Endodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Aichi 464-8651 (Japan); Kondo, Ayami [Department of Medicinal Biochemistry, School of Pharmacy, Aichi Gakuin University, Nagoya 464-8650 (Japan); Nakata, Kazuhiko [Department of Endodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Aichi 464-8651 (Japan); Mogi, Makio, E-mail: makio@dpc.agu.ac.jp [Department of Medicinal Biochemistry, School of Pharmacy, Aichi Gakuin University, Nagoya 464-8650 (Japan)

    2015-02-01

    We previously reported that interleukin 1β acts via matrix metalloproteinase (MMP)-3 to regulate cell proliferation and suppress apoptosis in α2 integrin-positive odontoblast-like cells differentiated from mouse embryonic stem (ES) cells. Here we characterize the signal cascade underpinning odontoblastic differentiation in mouse ES cells. The expression of α2 integrin, extracellular matrix metalloproteinase inducer (Emmprin), and MMP-3 mRNA and protein were all potently increased during odontoblastic differentiation. Small interfering RNA (siRNA) disruption of the expression of these effectors potently suppressed the expression of the odontoblastic biomarkers dentin sialophosphoprotein, dentin matrix protein-1 and alkaline phosphatase, and blocked odontoblast calcification. Our siRNA, western blot and blocking antibody analyses revealed a unique sequential cascade involving α2 integrin, Emmprin and MMP-3 that drives ES cell differentiation into odontoblasts. This cascade requires the interaction between α2 integrin and Emmprin and is potentiated by exogenous MMP-3. Finally, although odontoblast-like cells potently express α2, α6, αV, β1, and β3, integrins, we confirmed that β1 integrin acts as the trigger for ES cell differentiation, apparently in complex with α2 integrin. These results demonstrate a unique and unanticipated role for an α2 integrin-, Emmprin-, and MMP-3-mediated signaling cascade in driving mouse ES cell differentiation into odontoblast-like cells. - Highlights: • Odontoblast differentiation requires activation of α2 integrin, Emmprin and MMP-3. • α2 integrin, Emmprin and MMP-3 form a sequential signaling cascade. • β1 integrin acts a specific trigger for odontoblast differentiation. • The role of these effectors is highly novel and unanticipated.

  9. Effects of alternating and direct electrical current application on the odontoblastic layer in human teeth : an in vitro study

    NARCIS (Netherlands)

    Alwas-Danowska, HM; Huysmans, MCDNJM; Verdonschot, EH

    Aim The aim of this study was to investigate the influence of a low intensity alternating current on the odontoblasts and odontoblast layer and compare this with the effects of a direct current. Methodology Teeth extracted for orthodontic were immersed in physiological saline stabilized with thymol

  10. Effects of heat stress and starvation on clonal odontoblast-like cells.

    Science.gov (United States)

    Morotomi, Takahiko; Kitamura, Chiaki; Toyono, Takashi; Okinaga, Toshinori; Washio, Ayako; Saito, Noriko; Nishihara, Tatsuji; Terashita, Masamichi; Anan, Hisashi

    2011-07-01

    Heat stress during restorative procedures, particularly under severe starvation conditions, can trigger damage to dental pulp. In the present study, we examined effects of heat stress on odontoblastic activity and inflammatory responses in an odontoblast-like cell line (KN-3) under serum-starved conditions. Viability, nuclear structures, and inflammatory responses of KN-3 cells were examined in culture medium containing 10% or 1% serum after exposure to heat stress at 43°C for 45 minutes. Gene expression of extracellular matrices, alkaline phosphatase activity, and detection of extracellular calcium deposition in cells exposed to heat stress were also examined. Reduced viability and apoptosis were transiently induced in KN-3 cells during the initial phases after heat stress; thereafter, cells recovered their viability. The cytotoxic effects of heat stress were enhanced under serum-starved conditions. Heat stress also strongly up-regulated expression of heat shock protein 25 as well as transient expression of tumor necrosis factor-alpha, interleukin-6, and cyclooxygenase-2 in KN-3 cells. In contrast, expression of type-1 collagen, runt-related transcription factor 2, and dentin sialophosphoprotein were not inhibited by heat stress although starvation suppressed ALP activity and delayed progression of calcification. Odontoblast-like cells showed thermoresistance with transient inflammatory responses and without loss of calcification activity, and their thermoresistance and calcification activity were influenced by nutritional status. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  11. Caries induced cytokine network in the odontoblast layer of human teeth

    Directory of Open Access Journals (Sweden)

    Horst Jeremy A

    2011-01-01

    Full Text Available Abstract Background Immunologic responses of the tooth to caries begin with odontoblasts recognizing carious bacteria. Inflammatory propagation eventually leads to tooth pulp necrosis and danger to health. The present study aims to determine cytokine gene expression profiles generated within human teeth in response to dental caries in vivo and to build a mechanistic model of these responses and the downstream signaling network. Results We demonstrate profound differential up-regulation of inflammatory genes in the odontoblast layer (ODL in human teeth with caries in vivo, while the pulp remains largely unchanged. Interleukins, chemokines, and all tested receptors thereof were differentially up-regulated in ODL of carious teeth, well over one hundred-fold for 35 of 84 genes. By interrogating reconstructed protein interaction networks corresponding to the differentially up-regulated genes, we develop the hypothesis that pro-inflammatory cytokines highly expressed in ODL of carious teeth, IL-1β, IL-1α, and TNF-α, carry the converged inflammatory signal. We show that IL1β amplifies antimicrobial peptide production in odontoblasts in vitro 100-fold more than lipopolysaccharide, in a manner matching subsequent in vivo measurements. Conclusions Our data suggest that ODL amplifies bacterial signals dramatically by self-feedback cytokine-chemokine signal-receptor cycling, and signal convergence through IL1R1 and possibly others, to increase defensive capacity including antimicrobial peptide production to protect the tooth and contain the battle against carious bacteria within the dentin.

  12. The thickness of odontoblast-like cell layer after induced by propolis extract and calcium hydroxide

    Directory of Open Access Journals (Sweden)

    Irfan Dwiandhono

    2016-12-01

    Full Text Available Background: Propolis is a substance made from resin collected by bees (Apis mellifera from variety of plants, mixed with its saliva and various enzymes to build a nest. Propolis has potential antimicrobial and antiinflammatory agents with some advantages over calcium hydroxide (Ca(OH2. Ca(OH2 has been considered as the “gold standard” of direct pulp-capping materials, but there are still some weakness of its application. First, it can induce pulp inflammation which last up to 3 months. Second, the tissue response to Ca(OH2 is not always predictable. Third, the tunnel defect can probably formed in dentinal bridge with possible bacterial invasion in that gap. Purpose: This study was aimed to determine and compare the thickness of odontoblast-like cells layer after induced by propolis extract and Ca(OH2 in rat’s pulp tissue. Method: Class 1 preparation was done in maxillary first molar tooth of wistar mice until the pulp opened. The Ca(OH2 and propolis extract was applied to induce the formation of odontoblast-like cells, the cavity was filled with RMGIC. The teeth were extracted (after 14 and 28 days of induction. The samples were then processed for histological evaluation. Result: There were significant differences between the thickness of odontoblast-like cells after induced by propolis extract and Ca(OH2. Conclusion: The propolis extract as the direct pulp capping agent produces thicker odontoblast-like cell layer compared to Ca(OH2.

  13. The effect of delta-like 1 homologue on the proliferation and odontoblastic differentiation in human dental pulp stem cells.

    Science.gov (United States)

    Qi, Shengcai; Yan, Yanhong; Wen, Yue; Li, Jialiang; Wang, Jing; Chen, Fubo; Tang, Xiaoshan; Shang, Guangwei; Xu, Yuanzhi; Wang, Raorao

    2017-06-01

    This study aimed to investigate the functions of delta-like homologue 1 (DLK1) in the proliferation and differentiation of human dental pulp stem cells (hDPSCs). Immunohistochemical analysis was used to determine the expression of alkaline phosphatase (ALP), dentin sialophosphoprotein (DSPP), DLK1, NOTCH1 and p-ERK1/2 in the mouse first maxillary molar. Recombinant lentivirus was constructed to overexpress DLK1 stably in hDPSCs. The cell viability and proliferation of hDPSCs were examined by CCK8 and EdU incorporation assay respectively. The odontoblastic differentiation of hDPSCs was determined by detection of ALPase activity assay, ALP and alizarin red staining and the expression of mineralization-related genes including ALP, DSPP and dental matrix protein. The mRNA and protein levels of DLK1 and p-ERK1/2 protein expression were detected. ERK inhibitor was used to test the differentiation effect of DLK1 on hDPSCs. Delta-like homologue 1 was highly expressed on the odontoblasts and dental pulp cells on the first maxillary molar; the expression of p-ERK1/2 is similar with the DLK1 in the same process. The expression level of DLK1 increased significantly after the odontoblastic induction of hDPSCs. DLK1 overexpression increased the proliferation ability of hDPSCs and inhibited odontoblastic differentiation of hDPSCs. The protein level of p-ERK1/2 significantly increased in hDPSCs/dlk1-oe group. ERK signalling pathway inhibitor reversed the odontoblastic differentiation effects of DLK1 on hDPSCs. The proliferation of hDPSCs was promoted after DLK1 overexpression. DLK1 inhibited the odontoblastic differentiation of hDPSCs, which maybe through ERK signalling pathway. © 2017 John Wiley & Sons Ltd.

  14. Continuous fever-range heat stress induces thermotolerance in odontoblast-lineage cells.

    Science.gov (United States)

    Morotomi, Takahiko; Kitamura, Chiaki; Okinaga, Toshinori; Nishihara, Tatsuji; Sakagami, Ryuji; Anan, Hisashi

    2014-07-01

    Heat shock during restorative procedures can trigger damage to the pulpodentin complex. While severe heat shock has toxic effects, fever-range heat stress exerts beneficial effects on several cells and tissues. In this study, we examined whether continuous fever-range heat stress (CFHS) has beneficial effects on thermotolerance in the rat clonal dental pulp cell line with odontoblastic properties, KN-3. KN-3 cells were cultured at 41°C for various periods, and the expression level of several proteins was assessed by Western blot analysis. After pre-heat-treatment at 41°C for various periods, KN-3 cells were exposed to lethal severe heat shock (LSHS) at 49°C for 10min, and cell viability was examined using the MTS assay. Additionally, the expression level of odontoblast differentiation makers in surviving cells was examined by Western blot analysis. CFHS increased the expression levels of several heat shock proteins (HSPs) in KN-3 cells, and induced transient cell cycle arrest. KN-3 cells, not pre-heated or exposed to CFHS for 1 or 3h, died after exposure to LSHS. In contrast, KN-3 cells exposed to CFHS for 12h were transiently lower on day 1, but increased on day 3 after LSHS. The surviving cells expressed odontoblast differentiation markers, dentine sialoprotein and dentine matrix protein-1. These results suggest that CFHS for 12h improves tolerance to LSHS by inducing HSPs expression and cell cycle arrest in KN-3 cells. The appropriate pretreatment with continuous fever-range heat stress can provide protection against lethal heat shock in KN-3 cells. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. [miRNA profile of the human dental pulp cells during odontoblast differentiation induced by BMP-2].

    Science.gov (United States)

    Bao, Li-Rong; Zhao, Wen-Qing; Lin, Tian; Lu, Yan-Ling; Wu, Yu

    2017-10-01

    To screen and verify the differentially expressed microRNAs (miRNAs) during the differentiation of human dental pulp cells (hDPCs) to odontoblasts induced by BMP-2. The isolated hDPCs were cultured in vitro and induced by BMP-2. The levels of ALP, DMP-1 and DSPP were quantified by quantitative real-time polymerase chain reaction (qRT-PCR). The potential characteristics of hDPCs were investigated by miRNA microarray and highly expressed miRNAs were selected with bio-information software for predicting target genes and their biological functions. Then the results were validated using qRT-PCR analysis for the selected miRNAs. Statistical analysis was performed using SPSS 18.0 software package. The expression of ALP, DSPP, and DMP-1 showed significantly higher levels in BMP-2 induced groups compared to the control group(Pfunction(33%), while the function of other 0.2% genes remained unknown. This study identified differential expression of miRNAs in BMP-2-induced odontoblastic differentiation of hDPCs, thus contributing to further investigations of regulatory mechanisms and biological effect of target genes in BMP-2-induced odontoblastic differentiation of hDPCs.

  16. Differentiation of Odontoblast-Like Cells From Mouse Induced Pluripotent Stem Cells by Pax9 and Bmp4 Transfection.

    Science.gov (United States)

    Seki, Daisuke; Takeshita, Nobuo; Oyanagi, Toshihito; Sasaki, Shutaro; Takano, Ikuko; Hasegawa, Masakazu; Takano-Yamamoto, Teruko

    2015-09-01

    The field of tooth regeneration has progressed in recent years, and human tooth regeneration could become viable in the future. Because induced pluripotent stem (iPS) cells can differentiate into odontogenic cells given appropriate conditions, iPS cells are a potential cell source for tooth regeneration. However, a definitive method to induce iPS cell-derived odontogenic cells has not been established. We describe a novel method of odontoblast differentiation from iPS cells using gene transfection. We generated mouse iPS cell-derived neural crest-like cells (iNCLCs), which exhibited neural crest markers. Next, we differentiated iNCLCs into odontoblast-like cells by transfection of Pax9 and Bmp4 expression plasmids. Exogenous Pax9 upregulated expression of Msx1 and dentin matrix protein 1 (Dmp1) in iNCLCs but not bone morphogenetic protein 4 (Bmp4) or dentin sialophosphoprotein (Dspp). Exogenous Bmp4 upregulated expression of Msx1, Dmp1, and Dspp in iNCLCs, but not Pax9. Moreover, cotransfection of Pax9 and Bmp4 plasmids in iNCLCs revealed a higher expression of Pax9 than when Pax9 plasmid was used alone. In contrast, exogenous Pax9 downregulated Bmp4 overexpression. Cotransfection of Pax9 and Bmp4 synergistically upregulated Dmp1 expression; however, Pax9 overexpression downregulated exogenous Bmp4-induced Dspp expression. Together, these findings suggest that an interaction between exogenous Pax9- and Bmp4-induced signaling modulated Dmp1 and Dspp expression. In conclusion, transfection of Pax9 and Bmp4 expression plasmids in iNCLCs induced gene expression associated with odontoblast differentiation, suggesting that iNCLCs differentiated into odontoblast-like cells. The iPS cell-derived odontoblast-like cells could be a useful cell source for tooth regeneration. It has been reported that induced pluripotent stem (iPS) cells differentiate into odontogenic cells by administration of recombinant growth factors and coculture with odontogenic cells. Therefore, they can

  17. PDGFRβ+/c-kit+ pulp cells are odontoblastic progenitors capable of producing dentin-like structure in vitro and in vivo.

    Science.gov (United States)

    Cai, Shiwei; Zhang, Wenjian; Chen, Wei

    2016-10-28

    Successful pulp regeneration depends on identification of pulp stem cells capable of differentiation under odontoblastic lineage and producing pulp-dentinal like structure. Recent studies demonstrate that platelet-derived growth factor (PDGF) plays an important role in damage repair and tissue regeneration. The aim of this study was to identify a subpopulation of dental pulp cells responsive to PDGF and with dentin regeneration potential. Pulp tissues were isolated from 12 freshly extracted human impacted third molars. Pulp cells were sorted by their expression of PDGFRβ and stem cell marker genes via flow cytometry. For the selected cells, proliferation was analyzed by a colorimetric cell proliferation assay, differentiation was assessed by real time PCR detection the expression of odontoblast marker genes, and mineralization was evaluated by Alizarin Red S staining. GFP marked PDGFRβ + /c-kit + pulp cells were transplanted into emptied root canals of nude rat lower left incisors. Pulp-dentinal regeneration was examined by immunohistochemistry. PDGFRβ + /c-kit + pulp cells proliferated significantly faster than whole pulp cells. In mineralization media, PDGFRβ + /c-kit + pulp cells were able to develop under odontoblastic linage as demonstrated by a progressively increased expression of DMP1, DSPP, and osteocalcin. BMP2 seemed to enhance whereas PDGF-BB seemed to inhibit odontoblastic differentiation and mineralization of PDGFRβ + /c-kit + pulp cells. In vivo root canal transplantation study revealed globular dentin and pulp-like tissue formation by PDGFRβ + /c-kit + cells. PDGFRβ + /c-kit + pulp cells appear to have pulp stem cell potential capable of producing dentinal like structure in vitro and in vivo.

  18. IL-1β-induced, matrix metalloproteinase-3-regulated proliferation of embryonic stem cell-derived odontoblastic cells is mediated by the Wnt5 signaling pathway

    International Nuclear Information System (INIS)

    Ozeki, Nobuaki; Hase, Naoko; Hiyama, Taiki; Yamaguchi, Hideyuki; Kawai, Rie; Kondo, Ayami; Nakata, Kazuhiko; Mogi, Makio

    2014-01-01

    We previously established a method for differentiating induced pluripotent stem cells and embryonic stem (ES) cells into α2 integrin-positive odontoblast-like cells. We also reported that interleukin (IL)-1β induces matrix metalloproteinase (MMP)-3-regulated cell proliferation and suppresses apoptosis in these cells, suggesting that MMP-3 plays a potentially unique physiological role in the regeneration of odontoblast-like cells. Here, we examined whether up-regulation of MMP-3 activity by IL-1β was mediated by Wnt signaling and led to increased proliferation of odontoblast-like cells. IL-1β increased mRNA and protein levels of Wnt5a, Wnt5b and the Wnt receptor Lrp5. Exogenous Wnt5a and Wnt5b were found to increase MMP-3 mRNA, protein and activity, and interestingly the rate of proliferation in these cells. Treatment with siRNAs against Wnt5a, Wnt5b and Lrp5 suppressed the IL-1β-induced increase in MMP-3 expression and suppressed cell proliferation, an effect rescued by application of exogenous Wnt5. These results demonstrate the sequential involvement of Wnt5, Lrp5 and MMP-3 in effecting IL-1β-induced proliferation of ES cell-derived odontoblast-like cells. - Highlights: • IL-1β induces Wnt5, Lrp5/Fzd9 and MMP-3 in ES cell-derived odontoblast-like cells. • IL-1β-induced Wnt5 expression results in increased cell proliferation. • Exogenous Wnt5 increases MMP-3 activity and cell proliferation. • Exogenous Wnt5 rescues IL-1β-driven proliferation with anti-Wnt5 siRNA suppression. • IL-1β-induced cell proliferation involves Wnt5, Lrp5, and MMP-3 sequentially

  19. IL-1β-induced, matrix metalloproteinase-3-regulated proliferation of embryonic stem cell-derived odontoblastic cells is mediated by the Wnt5 signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Ozeki, Nobuaki; Hase, Naoko; Hiyama, Taiki; Yamaguchi, Hideyuki; Kawai, Rie [Department of Endodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Aichi 464-8651 (Japan); Kondo, Ayami [Department of Medicinal Biochemistry, School of Pharmacy, Aichi Gakuin University, Nagoya 464-8650 (Japan); Nakata, Kazuhiko [Department of Endodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Aichi 464-8651 (Japan); Mogi, Makio, E-mail: makio@dpc.agu.ac.jp [Department of Medicinal Biochemistry, School of Pharmacy, Aichi Gakuin University, Nagoya 464-8650 (Japan)

    2014-10-15

    We previously established a method for differentiating induced pluripotent stem cells and embryonic stem (ES) cells into α2 integrin-positive odontoblast-like cells. We also reported that interleukin (IL)-1β induces matrix metalloproteinase (MMP)-3-regulated cell proliferation and suppresses apoptosis in these cells, suggesting that MMP-3 plays a potentially unique physiological role in the regeneration of odontoblast-like cells. Here, we examined whether up-regulation of MMP-3 activity by IL-1β was mediated by Wnt signaling and led to increased proliferation of odontoblast-like cells. IL-1β increased mRNA and protein levels of Wnt5a, Wnt5b and the Wnt receptor Lrp5. Exogenous Wnt5a and Wnt5b were found to increase MMP-3 mRNA, protein and activity, and interestingly the rate of proliferation in these cells. Treatment with siRNAs against Wnt5a, Wnt5b and Lrp5 suppressed the IL-1β-induced increase in MMP-3 expression and suppressed cell proliferation, an effect rescued by application of exogenous Wnt5. These results demonstrate the sequential involvement of Wnt5, Lrp5 and MMP-3 in effecting IL-1β-induced proliferation of ES cell-derived odontoblast-like cells. - Highlights: • IL-1β induces Wnt5, Lrp5/Fzd9 and MMP-3 in ES cell-derived odontoblast-like cells. • IL-1β-induced Wnt5 expression results in increased cell proliferation. • Exogenous Wnt5 increases MMP-3 activity and cell proliferation. • Exogenous Wnt5 rescues IL-1β-driven proliferation with anti-Wnt5 siRNA suppression. • IL-1β-induced cell proliferation involves Wnt5, Lrp5, and MMP-3 sequentially.

  20. Effect of low dose radiation on the odontogenesis of mice foetus

    International Nuclear Information System (INIS)

    Osman, M.; Al-Achkar, W.

    1998-09-01

    Mice foetuses were irradiated in utero by gamma rays (0,2, 4,6 Gy) at 10, 12, 14, 16, 18 days of gestation. Histological study was carried out on the first premandibular tooth after 2,4,6,8 days of irradiation, to investigate the effect of irradiation on different steps of tooth development. It appeared that the irradiation induced a delay in the tooth development depending on the time of irradiation and period of gestation. The 2 Gy irradiation effect was small. The 4 Gy dose induced a delay of the cytodifferentiation of the odontoblasts and the ameloblasts. These effects were associated with a morphological retardation in the coronal and the tooth root. More pronounced effects after 6 Gy irradiation for all aspects of the odontogenesis were observed. It caused a strong decrease in the tooth development of the anlages (irradiation of day 12 of the gestation), blocked the morphogenesis (irradiation of day 14), and delayed the cytodifferentiation of the odontoblasts and the amelobasts (irradiation of day 16). Whereas the irradiation at the day 18 had no effects on the functional differentiation of the odontoblasts, but a delay in the functional differentiation of the ameloblasts was observed. Our results show, in our experimental conditions, that irradiation effect the processes prior to the cytodifferentiation of the ameloblasts and the odontoblasts and there are no effects to be observed on the cyto and functional differentiation of these two blasts when their cells achieved its final differentiation. (author)

  1. Determination of inorganic pyrophosphatase in rat odontoblast layer by a radiochemical method

    International Nuclear Information System (INIS)

    Granstroem, G.; Linde, A.

    1975-01-01

    The enzyme inorganic pyrophosphatase (PPsub(i)ase, EC 3.6.1.1) from the odontoblastic layer of rat incisors has been studied by means of a radiochemical micromethod. The enzyme was incubated with 32 P-pyrophosphate in tris-HCl buffer at 37degC. The reaction was linear with time fr at least 45 min, and the pH optimum was found to be 8.8, independent of the amount of pyrophosphate present. Heating the enzyme at 56degC inhibited the enzyme activity rapidly, Mg 2+ ions activated the enzyme by 15 % at an ion concentration of 4 mM, while higher concentrations were inhibitory. Ca 2+ ions and PO 4 3- ions inhibited the enzyme at all concentrations. F - ions did not affect the PPsub(i)ase at concentrations below 8 mM, whereas higher concentrations had an inhibiting effect. Urea was found to inhibit the enzyme at concentrations above 1.5 M, while EDTA was a strong inhibitor at very low concentrations. The characteristics of PPsub(i)ase agree well with the properties of the enzyme nonspecific alkaline phosphatase (EC 3.1.3.1.) studied earlier. (author)

  2. Electron microscopic studies on odontoblasts using 45Ca as the tracer

    International Nuclear Information System (INIS)

    Okamoto, Eiji

    1980-01-01

    In order to study the relationship between odontoblasts and inorganic salts, odontoblasts of 10-day old rats' incisions and molars were used. The animals were sacrificed 15 minutes, 30 minutes, 1 hour or 2 hours after 45 Ca administration to obtain the specimen. The specimens were processed for electron microscopic autoradiography. 15 minutes after 45 Ca administration, silver grains indicated 45 Ca uptake was already noted within the cells. 45 Ca was localized in the mitochondria, Golgi area, rough surfaced endoplasmic reticulum and partially within the karyoplasm. After 30 minutes' administration, the number of silver grains were generally increased as compared with the findings obtained after 15 minutes' administration. The localization was similar with those after 15 minutes' administration but some were found in the ribosomes and smooth surfaced endoplasmic reticulum with numerous silver grains within small vesicles derived from the Golgi apparatus as well. A movement of 45 Ca from the protruding part to the stroma was also noted. 1 hour after the administration, the number of silver grains were generally decreased, with a more pronounced movement towards stroma from the protruding part. The marked movement of silver grains was obtained onto the collagen fibers in the stroma. In the mitochondria, however, considerable number of silver grains were still seen. In this section, on the other hand, numerous silver grains were seen in the intercellular space, in addition to the pathway of intracellular route, indicating the Ca shift from outside of the cells. After 2 hours' 45 Ca administration, the tendency towards the decrease of the silver grains became more remarkable, the movement of 45 Ca via the extracellular pathway described above was also frequently found. (author)

  3. Semaphorin 3A Induces Odontoblastic Phenotype in Dental Pulp Stem Cells.

    Science.gov (United States)

    Yoshida, S; Wada, N; Hasegawa, D; Miyaji, H; Mitarai, H; Tomokiyo, A; Hamano, S; Maeda, H

    2016-10-01

    In cases of pulp exposure due to deep dental caries or severe traumatic injuries, existing pulp-capping materials have a limited ability to reconstruct dentin-pulp complexes and can result in pulpectomy because of their low potentials to accelerate dental pulp cell activities, such as migration, proliferation, and differentiation. Therefore, the development of more effective therapeutic agents has been anticipated for direct pulp capping. Dental pulp tissues are enriched with dental pulp stem cells (DPSCs). Here, the authors investigated the effects of semaphorin 3A (Sema3A) on various functions of human DPSCs in vitro and reparative dentin formation in vivo in a rat dental pulp exposure model. Immunofluorescence staining revealed expression of Sema3A and its receptor Nrp1 (neuropilin 1) in rat dental pulp tissue and human DPSC clones. Sema3A induced cell migration, chemotaxis, proliferation, and odontoblastic differentiation of DPSC clones. In addition, Sema3A treatment of DPSC clones increased β-catenin nuclear accumulation, upregulated expression of the FARP2 gene (FERM, RhoGEF, and pleckstrin domain protein 2), and activated Rac1 in DPSC clones. Furthermore, in the rat dental pulp exposure model, Sema3A promoted reparative dentin formation with dentin tubules and a well-aligned odontoblast-like cell layer at the dental pulp exposure site and with novel reparative dentin almost completely covering pulp tissue at 4 wk after direct pulp capping. These findings suggest that Sema3A could play an important role in dentin regeneration via canonical Wnt/β-catenin signaling. Sema3A might be an alternative agent for direct pulp capping, which requires further study. © International & American Associations for Dental Research 2016.

  4. The increasing of odontoblast-like cell number on direct pulp capping of Rattus norvegicus using chitosan

    Directory of Open Access Journals (Sweden)

    Widyasri Prananingrum

    2010-12-01

    Full Text Available Background: Pulpal perforation care with direct pulp capping in the case of reversible pulpitis due to mechanical trauma was performed with chitosan which has the ability to facilitate migration, proliferation, and progenitor cell differentiation. Purpose: The purpose of this study was to determine the increasing number of odontoblast-like cells in direct pulp capping dental care of Rattus norvegicus using chitosan for seven and fourteen days. Methods: Samples were molars of male Rattus norvegicus strain wistar, aged between 8–16 weeks, divided into two treatment groups, namely group I given chitosan and group II as a control group given Ca(OH2. Those Rattus norvegicus’ occlusal molar teeth were prepared with class I cavity, and then chitosan and Ca(OH2 were applied as the pulp capping materials. Afterwards, glasss ionomer cement type IX was used as a restoration material. Their teeth and jaw were then cut on the seventh day and the fourteenth day. Next, histopathological examination was carried out to observe the odontoblast like cells. All data were then analyzed by t test. Degree of confidence obtained, finally, was 95%. Results: The results obtained showed that the significant differences of odontoblast like cells on the seventh day observation was 0.001 (p = 0.001, and on the fourteenth day observation was 0.002 (p = 0.002. Conclusion: The number of odontoblast-like cells in direct pulp capping dental care of rattus norvegicus using chitosan is higher than the one using Ca(OH2 for seven and fourteen days.Latar belakang: Perawatan perforasi pulpa pada kasus pulpitis reversible karena trauma mekanis bur dilakukan direct pulp capping dengan cara pemberian bahan secara topikal pada daerah perforasi. Kitosan memiliki kemampuan untuk memfasilitasi migrasi, proliferasi dan diferensiasi sel progenitor pulpa. Tujuan: Tujuan penelitian ini adalah untuk menentukan jumlah peningkatan odontoblas-like cell pada perawatan direct pulp capping gigi

  5. Factors affecting patient dose in diagnostic radiology

    International Nuclear Information System (INIS)

    Poletti, J.L.

    1994-03-01

    The report, Factors Affecting Patient Dose in Diagnostic Radiology is divided into three main sections. Part one is introductory and covers the basic principles of x-ray production and image formation. It includes discussion of x-ray generators and x-ray tubes, radiation properties and units, specification and measurement of x-ray beams, methods of patient dose measurement, radiation effects, radiation protection philosophy and finally the essentials of imaging systems. Part two examines factors affecting the x-ray output of x-ray machines and the characteristics of x-ray beams. These include the influence of heat ratings, kVp, waveform, exposure timer, filtration, focus-film distance, beam intensity distribution, x-ray tube age and focal spot size. Part three examines x-ray machine, equipment and patient factors which affect the dose received by individual patients. The factors considered include justification of examinations, choice of examination method, film/screen combinations, kVp, mAs, focus-film distance, collimation and field size, exposure time, projection, scatter, generator calibration errors, waveform, filtration, film processing and patient size. The patient dose implications of fluoroscopy systems, CT scanners, special procedures and mammography are also discussed. The report concludes with a brief discussion of patient dose levels in New Zealand and dose optimisation. 104 refs., 32 figs., 27 tabs

  6. The increasing of odontoblast-like cell number on direct pulp capping of Rattus norvegicus using chitosan

    OpenAIRE

    Prananingrum, Widyasri

    2010-01-01

    Background: Pulpal perforation care with direct pulp capping in the case of reversible pulpitis due to mechanical trauma was performed with chitosan which has the ability to facilitate migration, proliferation, and progenitor cell differentiation. Purpose: The purpose of this study was to determine the increasing number of odontoblast-like cells in direct pulp capping dental care of Rattus norvegicus using chitosan for seven and fourteen days. Methods: Samples were molars of male Rattus norve...

  7. Identification of Cells at Early and Late Stages of Polarization During Odontoblast Differentiation Using pOBCol3.6GFP and pOBCol2.3GFP Transgenic Mice

    Science.gov (United States)

    Balic, Anamaria; Aguila, H. Leonardo; Mina, Mina

    2010-01-01

    Transgenic mouse lines in which GFP expression is under the control of tissue-and stage specific promoters have provided powerful experimental tools for identification and isolation of cells at specific stage of differentiation along a lineage. In the present study we used primary cell cultures derived from the dental pulp from pOBCol3.6GFP and pOBCol2.3GFP transgenic mice as a model to develop markers for early stages of odontoblast differentiation from progenitor cells. We analyzed the temporal and spatial expression of 2.3-GFP and 3.6-GFP during in vitro mineralization. Using FACS to separate cells based on GFP expression, we obtained relatively homogenous sub-populations of cells and analyzed their dentinogenic potentials and their progression into odontoblasts. Our observations showed that these transgenes were activated before the onset of matrix deposition and in cells at different stages of polarization. The 3.6-GFP transgene was activated in cells in early stages of polarization whereas the 2.3-GFP transgene was activated at a later stage of polarization just before or at the time of formation of secretory odontoblast. PMID:20728593

  8. Alcohol Inhibits Odontogenic Differentiation of Human Dental Pulp Cells by Activating mTOR Signaling

    Directory of Open Access Journals (Sweden)

    Wei Qin

    2017-01-01

    Full Text Available Long-term heavy alcohol consumption could result in a range of health, social, and behavioral problems. People who abuse alcohol are at high risks of seriously having osteopenia, periodontal disease, and compromised oral health. However, the role of ethanol (EtOH in the biological functions of human dental pulp cells (DPCs is unknown. Whether EtOH affects the odontoblastic differentiation of DPCs through the mechanistic target of rapamycin (mTOR remains unexplored. The objective of this study was to investigate the effects of EtOH on DPC differentiation and mineralization. DPCs were isolated and purified from human dental pulps. The proliferation and odontoblastic differentiation of DPCs treated with EtOH were subsequently investigated. Different doses of EtOH were shown to be cytocompatible with DPCs. EtOH significantly activated the mTOR pathway in a dose-dependent manner. In addition, EtOH downregulated the alkaline phosphatase activity, attenuated the mineralized nodule formation, and suppressed the expression of odontoblastic markers including ALP, DSPP, DMP-1, Runx2, and OCN. Moreover, the pretreatment with rapamycin, a specific mTOR inhibitor, markedly reversed the EtOH-induced odontoblastic differentiation and cell mineralization. Our findings show for the first time that EtOH can suppress DPC differentiation and mineralization in a mTOR-dependent manner, indicating that EtOH may be involved in negatively regulating the dental pulp repair.

  9. Alcohol Inhibits Odontogenic Differentiation of Human Dental Pulp Cells by Activating mTOR Signaling.

    Science.gov (United States)

    Qin, Wei; Huang, Qi-Ting; Weir, Michael D; Song, Zhi; Fouad, Ashraf F; Lin, Zheng-Mei; Zhao, Liang; Xu, Hockin H K

    2017-01-01

    Long-term heavy alcohol consumption could result in a range of health, social, and behavioral problems. People who abuse alcohol are at high risks of seriously having osteopenia, periodontal disease, and compromised oral health. However, the role of ethanol (EtOH) in the biological functions of human dental pulp cells (DPCs) is unknown. Whether EtOH affects the odontoblastic differentiation of DPCs through the mechanistic target of rapamycin (mTOR) remains unexplored. The objective of this study was to investigate the effects of EtOH on DPC differentiation and mineralization. DPCs were isolated and purified from human dental pulps. The proliferation and odontoblastic differentiation of DPCs treated with EtOH were subsequently investigated. Different doses of EtOH were shown to be cytocompatible with DPCs. EtOH significantly activated the mTOR pathway in a dose-dependent manner. In addition, EtOH downregulated the alkaline phosphatase activity, attenuated the mineralized nodule formation, and suppressed the expression of odontoblastic markers including ALP, DSPP, DMP-1, Runx2, and OCN. Moreover, the pretreatment with rapamycin, a specific mTOR inhibitor, markedly reversed the EtOH-induced odontoblastic differentiation and cell mineralization. Our findings show for the first time that EtOH can suppress DPC differentiation and mineralization in a mTOR-dependent manner, indicating that EtOH may be involved in negatively regulating the dental pulp repair.

  10. Combination of Mineral Trioxide Aggregate and Platelet-rich Fibrin Promotes the Odontoblastic Differentiation and Mineralization of Human Dental Pulp Cells via BMP/Smad Signaling Pathway.

    Science.gov (United States)

    Woo, Su-Mi; Kim, Won-Jae; Lim, Hae-Soon; Choi, Nam-Ki; Kim, Sun-Hun; Kim, Seon-Mi; Jung, Ji-Yeon

    2016-01-01

    Recent reports have shown that the combined use of platelet-rich fibrin (PRF), an autologous fibrin matrix, and mineral trioxide aggregate (MTA) as root filling material is beneficial for the endodontic management of an open apex. However, the potential of the combination of MTA and PRF as an odontogenic inducer in human dental pulp cells (HDPCs) in vitro has not yet been studied. The purpose of this study was to evaluate the effect of the combination of MTA and PRF on odontoblastic maturation in HDPCs. HDPCs extracted from third molars were directly cultured with MTA and PRF extract (PRFe). Odontoblastic differentiation of HDPCs was evaluated by measuring the alkaline phosphatase (ALP) activity, and the expression of odontogenesis-related genes was detected using reverse-transcription polymerase chain reaction or Western blot. Mineralization formation was assessed by alizarin red staining. HDPCs treated with MTA and PRFe significantly up-regulated the expression of dentin sialoprotein and dentin matrix protein-1 and enhanced ALP activity and mineralization compared with those with MTA or PRFe treatment alone. In addition, the combination of MTA and PRFe induced the activation of bone morphogenic proteins (BMP)/Smad, whereas LDN193189, the bone morphogenic protein inhibitor, attenuated dentin sialophosphoprotein and dentin matrix protein-1 expression, ALP activity, and mineralization enhanced by MTA and PRFe treatment. This study shows that the combination of MTA and PRF has a synergistic effect on the stimulation of odontoblastic differentiation of HDPCs via the modulation of the BMP/Smad signaling pathway. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  11. A systematic study on factors affecting patient dose, (1)

    International Nuclear Information System (INIS)

    Otsuka, Akiyoshi; Higashida, Yoshiharu; Utsumi, Hiromoto; Ota, Masaji; Nakanishi, Takashi

    1979-01-01

    In the study of possible reduction in irradiation dose to patients during medical treatments, the following two methods can be considered: (1) To obtain absorbed doses for each part of a body in diagnostic X-ray examinations. (2) To obtain data on factors such as the tube voltage which may affect patient dose. There are a number of reports both at home and abroad concerning the above (1), but very few reports are available concerning the above (2). Moreover, most of them are on fragmentary aspects of each factor and no systematic reports have been made. For this reason, we have taken up, as factors affecting the patient dose, the field size, the tube voltage, and by checking them again, we wanted to obtain some systematic data. Our aim has been fully attained by conducting an experiment. In the ICRP's Publ. 26 issued last year, the idea of the critical organ which had not been fully elucidated in the Publ. 9 was abandoned. As a result, assessment of the irradiation doses has become more rational and the total risk for an individual was obtained. In Japan, the idea proposed in the Publ. 9 is adopted. Therefore, in this paper, we will raise some questions regarding the assessment of the irradiation doses, pointing out at the same time the rationality of the idea put forward in Publ. 26. (author)

  12. Gamma-Ray Doses Affected on Alfalfa (Medicago sativa L.)

    International Nuclear Information System (INIS)

    Zayed, E.M; Tarrad, M.M.; Abd El-Daem, G.A.N.A.

    2013-01-01

    Field experiments were conducted at the experimental from, Nuclear Research Center at Inshas. Atomic Energy Authority (AEA) at Egypt during 2011– 2012 growing seasons on alfalfa genotype. The aim of this investigation to evaluate the effect of different gamma ray doses (100-300 Gy) on the alfalfa yield and related traits. Seeds lots of alfalfa genotype were subjected to five gamma ray treatments (100,150,200,250 and 300 Gray). Over all cuts, the dose treatment 300 Gy increased the majority of studied traits i.e., plant height, No. of shoots/plant, fresh weight/plant, fresh yield/Fadden and dry weight yield/fed. The results observed indicated that. In addition, dose of 200 and 250 Gy increased No. of leaves /plant, No. of shoots/plant, stem diameter and fresh weight /plant. However, the plant dry weight was decreased by all doses used and over all cuts, but the dose of 100 and 150 Gy increased leaves /stem ratio. Meanwhile, the later cuts were more affected by irradiation treatments than the earlier ones. In general, the low doses had negative effects on yield traits, but, the relatively high doses exhibited an increase in yield traits

  13. Aquatic pathway variables affecting the estimation of dose commitment from uranium mill tailings

    International Nuclear Information System (INIS)

    Lush, D.L.; Snodgrass, W.J.; McKee, P.

    1982-01-01

    As one of a series of studies being carried out for the Atomic Energy Control Board of Canada, the environmental variables affecting population dose commitment and critical group dose rates from aquatic pathways were investigated. A model was developed to follow uranium and natural thorium decay series radionuclides through aquatic pathways leading both to long-term sediment sinks and to man. Pathways leading to man result in both a population dose commitment and a critical group dose rate. The key variables affecting population dose commitment are suspended particulate concentrations in the receiving aquatic systems, the settling velocities of these particulates and the solid-aqueous phase distribution coefficient associated with each radionuclide. Of secondary importance to population dose commitment are the rate at which radionuclides enter the receiving waters and the value of the water to food transfer coefficients that are used in the model. For the critical group dose rate, the rate at which the radionuclides leave the tailings, the water to food transfer coefficients, the rate of water and fish consumption and the dose conversion factors for 210 Pb and 210 Po are of secondary importance (author)

  14. Radiation dose exposure in patients affected by lymphoma undergoing repeat CT examinations: how to manage the radiation dose variability.

    Science.gov (United States)

    Paolicchi, Fabio; Bastiani, Luca; Guido, Davide; Dore, Antonio; Aringhieri, Giacomo; Caramella, Davide

    2018-03-01

    To assess the variability of radiation dose exposure in patients affected by lymphoma undergoing repeat CT (computed tomography) examinations and to evaluate the influence of different scan parameters on the overall radiation dose. A series of 34 patients (12 men and 22 women with a median age of 34.4 years) with lymphoma, after the initial staging CT underwent repeat follow-up CT examinations. For each patient and each repeat examination, age, sex, use of AEC system (Automated Exposure Control, i.e. current modulation), scan length, kV value, number of acquired scans (i.e. number of phases), abdominal size diameter and dose length product (DLP) were recorded. The radiation dose of just one venous phase was singled out from the DLP of the entire examination. All scan data were retrieved by our PACS (Picture Archiving and Communication System) by means of a dose monitoring software. Among the variables we considered, no significant difference of radiation dose was observed among patients of different ages nor concerning tube voltage. On the contrary the dose delivered to the patients varied depending on sex, scan length and usage of AEC. No significant difference was observed depending on the behaviour of technologists, while radiologists' choices had indirectly an impact on the radiation dose due to the different number of scans requested by each of them. Our results demonstrate that patients affected by lymphoma who undergo repeat whole body CT scanning may receive unnecessary overexposure. We quantified and analyzed the most relevant variables in order to provide a useful tool to manage properly CT dose variability, estimating the amount of additional radiation dose for every single significant variable. Additional scans, incorrect scan length and incorrect usage of AEC system are the most relevant cause of patient radiation exposure.

  15. 4D dose simulation in volumetric arc therapy: Accuracy and affecting parameters

    Science.gov (United States)

    Werner, René

    2017-01-01

    Radiotherapy of lung and liver lesions has changed from normofractioned 3D-CRT to stereotactic treatment in a single or few fractions, often employing volumetric arc therapy (VMAT)-based techniques. Potential unintended interference of respiratory target motion and dynamically changing beam parameters during VMAT dose delivery motivates establishing 4D quality assurance (4D QA) procedures to assess appropriateness of generated VMAT treatment plans when taking into account patient-specific motion characteristics. Current approaches are motion phantom-based 4D QA and image-based 4D VMAT dose simulation. Whereas phantom-based 4D QA is usually restricted to a small number of measurements, the computational approaches allow simulating many motion scenarios. However, 4D VMAT dose simulation depends on various input parameters, influencing estimated doses along with mitigating simulation reliability. Thus, aiming at routine use of simulation-based 4D VMAT QA, the impact of such parameters as well as the overall accuracy of the 4D VMAT dose simulation has to be studied in detail–which is the topic of the present work. In detail, we introduce the principles of 4D VMAT dose simulation, identify influencing parameters and assess their impact on 4D dose simulation accuracy by comparison of simulated motion-affected dose distributions to corresponding dosimetric motion phantom measurements. Exploiting an ITV-based treatment planning approach, VMAT treatment plans were generated for a motion phantom and different motion scenarios (sinusoidal motion of different period/direction; regular/irregular motion). 4D VMAT dose simulation results and dose measurements were compared by local 3% / 3 mm γ-evaluation, with the measured dose distributions serving as ground truth. Overall γ-passing rates of simulations and dynamic measurements ranged from 97% to 100% (mean across all motion scenarios: 98% ± 1%); corresponding values for comparison of different day repeat measurements were

  16. Limestone doses affecting mineral contents in tropical grass forage

    International Nuclear Information System (INIS)

    Armelin, M.J.A.; Saiki, M.

    2005-01-01

    Field trial was performed at the experimental farm of Southeast Embrapa Cattle, Sao Carlos - SP, Brazil, on a 16 year old Brachiaria decumbens pasture, grown on a distrophic Hapludox (Oxisol), recovered by the use of limestone and fertilizer. The experiments were carried out in random blocks, with 6 replications and 5 treatments. The 100 m 2 blocks were established in the pasture. Each block received a sequence of limestone doses of 0, 1, 2, 4 and 8 t/ha. The forage samples were taken one year after limestone application on soil surface. Instrumental neutron activation analysis (INAA) followed by gamma-ray spectrometry was the analytical method used to determine mineral contents. The statistical analysis showed a negative linear correlation of Br, Co, Cr, Mn and Zn contents in forage with the limestone doses, while the uptake of Mg was affected in a positive way. (author)

  17. Carbon dioxide inhalation induces dose-dependent and age-related negative affectivity.

    Directory of Open Access Journals (Sweden)

    Eric J Griez

    Full Text Available BACKGROUND: Carbon dioxide inhalation is known to induce an emotion similar to spontaneous panic in Panic Disorder patients. The affective response to carbon dioxide in healthy subjects was not clearly characterized yet. METHODOLOGY/PRINCIPAL FINDINGS: Sixty-four healthy subjects underwent a double inhalation of four mixtures containing respectively 0, 9, 17.5 and 35% CO(2 in compressed air, following a double blind, cross-over, randomized design. Affective responses were assessed according to DSM IV criteria for panic, using an Electronic Visual Analogue Scale and the Panic Symptom List. It was demonstrated that carbon dioxide challenges induced a dose dependent negative affect (p<0.0001. This affect was semantically identical to the DSM IV definition of panic. Older individuals were subjectively less sensitive to Carbon Dioxide (p<0.05. CONCLUSIONS/SIGNIFICANCE: CO(2 induced affectivity may lay on a continuum with pathological panic attacks. Consistent with earlier suggestions that panic is a false biological alarm, the affective response to CO(2 may be part of a protective system triggered by suffocation and acute metabolic distress.

  18. EMMPRIN/CD147 deficiency disturbs ameloblast-odontoblast cross-talk and delays enamel mineralization.

    Science.gov (United States)

    Khaddam, Mayssam; Huet, Eric; Vallée, Benoît; Bensidhoum, Morad; Le Denmat, Dominique; Filatova, Anna; Jimenez-Rojo, Lucia; Ribes, Sandy; Lorenz, Georg; Morawietz, Maria; Rochefort, Gael Y; Kiesow, Andreas; Mitsiadis, Thimios A; Poliard, Anne; Petzold, Matthias; Gabison, Eric E; Menashi, Suzanne; Chaussain, Catherine

    2014-09-01

    Tooth development is regulated by a series of reciprocal inductive signaling between the dental epithelium and mesenchyme, which culminates with the formation of dentin and enamel. EMMPRIN/CD147 is an Extracellular Matrix MetalloPRoteinase (MMP) INducer that mediates epithelial-mesenchymal interactions in cancer and other pathological processes and is expressed in developing teeth. Here we used EMMPRIN knockout (KO) mice to determine the functional role of EMMPRIN on dental tissue formation. We report a delay in enamel deposition and formation that is clearly distinguishable in the growing incisor and associated with a significant reduction of MMP-3 and MMP-20 expression in tooth germs of KO mice. Insufficient basement membrane degradation is evidenced by a persistent laminin immunostaining, resulting in a delay of both odontoblast and ameloblast differentiation. Consequently, enamel volume and thickness are decreased in adult mutant teeth but enamel maturation and tooth morphology are normal, as shown by micro-computed tomographic (micro-CT), nanoindentation, and scanning electron microscope analyses. In addition, the dentino-enamel junction appears as a rough calcified layer of approximately 10±5μm thick (mean±SD) in both molars and growing incisors of KO adult mice. These results indicate that EMMPRIN is involved in the epithelial-mesenchymal cross-talk during tooth development by regulating the expression of MMPs. The mild tooth phenotype observed in EMMPRIN KO mice suggests that the direct effect of EMMPRIN may be limited to a short time window, comprised between basement membrane degradation allowing direct cell contact and calcified matrix deposition. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Biphasic effects of FGF2 on odontoblast differentiation involve changes in the BMP and Wnt signaling pathways.

    Science.gov (United States)

    Sagomonyants, Karen; Mina, Mina

    2014-08-01

    Odontoblast differentiation during physiological and reparative dentinogenesis is dependent upon multiple signaling molecules, including fibroblast growth factors (FGFs), bone morphogenetic proteins (BMPs) and Wingless/Integrated (Wnt) ligands. Recent studies in our laboratory showed that continuous exposure of primary dental pulp cultures to FGF2 exerted biphasic effects on the expression of markers of dentinogenesis. In the present study, we examined the possible involvement of the BMP and Wnt signaling pathways in mediating the effects of FGF2 on dental pulp cells. Our results showed that stimulatory effects of FGF2 on dentinogenesis during the proliferation phase of growth were associated with increased expression of the components of the BMP (Bmp2, Dlx5, Msx2, Osx) and Wnt (Wnt10a, Wisp2) pathways, and decreased expression of an inhibitor of the Wnt signaling, Nkd2. Further addition of FGF2 during the differentiation/mineralization phase of growth resulted in decreased expression of components of the BMP signaling (Bmp2, Runx2, Osx) and increased expression of inhibitors of the Wnt signaling (Nkd2, Dkk3). This suggests that both BMP and Wnt pathways may be involved in mediating the effects of FGF2 on dental pulp cells.

  20. Involvement of TRPV1 and AQP2 in hypertonic stress by xylitol in odontoblast cells.

    Science.gov (United States)

    Tokuda, M; Fujisawa, M; Miyashita, K; Kawakami, Y; Morimoto-Yamashita, Y; Torii, M

    2015-02-01

    To examine the responses of mouse odontoblast-lineage cell line (OLC) cultures to xylitol-induced hypertonic stress. OLCs were treated with xylitol, sucrose, sorbitol, mannitol, arabinose and lyxose. Cell viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium assay. The expression of transient receptor potential vanilloids (TRPV) 1, 3 and 4 was detected using a reverse transcriptase-polymerase chain reaction (RT-PCR) assay. The expression of aquaporin (AQP) 2 was detected using immunofluorescence and Western blotting analysis. The expression of interleukin-6 (IL-6) under xylitol-induced hypertonic stress was assessed using an enzyme-linked immunosorbent assay (ELISA). Small interfering ribonucleic acid (siRNA) for AQP-2 was used to inhibition assay. Xylitol-induced hypertonic stress did not decrease OLC viability, unlike the other sugars tested. OLCs expressed TRPV1, 3 and 4 as well as AQP2. Xylitol inhibited lipopolysaccharide (LPS)-induced IL-6 expression after 3 h of hypertonic stress. TRPV1 mRNA expression was upregulated by xylitol. Costimulation with HgCl2 (AQP inhibitor) and Ruthenium red (TRPV1 inhibitor) decreased cell viability with xylitol stimulation. OLCs treated with siRNA against TRPV1 exhibited decreased cell viability with xylitol stimulation. OLCs have high-cell viability under xylitol-induced hypertonic stress, which may be associated with TRPV1 and AQP2 expressions.

  1. Can prenatal low-dose irradiation affect behavior of adult rats?

    International Nuclear Information System (INIS)

    Smajda, B.; Tomasova, L.; Kokocova, N.

    2011-01-01

    The aim of our study was to determine whether exposure of very low dose gamma-rays during the critical phase of brain development affects some selected behavioral parameters in adult rats. Pregnant female Wistar rats were irradiated with 1 Gy gamma-rays from a cobalt source at 17 th day of pregnancy. The progeniture of irradiated as well as non-irradiated females have undergone behavioral tests at the age of 3 months. Irradiated animals exhibited lower locomotor and exploratory activity in the open field test. (authors)

  2. Pulpal responses to cavity preparation in aged rat molars.

    Science.gov (United States)

    Kawagishi, Eriko; Nakakura-Ohshima, Kuniko; Nomura, Shuichi; Ohshima, Hayato

    2006-10-01

    The dentin-pulp complex is capable of repair after tooth injuries including dental procedures. However, few data are available concerning aged changes in pulpal reactions to such injuries. The present study aimed to clarify the capability of defense in aged pulp by investigating the responses of odontoblasts and cells positive for class II major histocompatibility complex (MHC) to cavity preparation in aged rat molars (300-360 days) and by comparing the results with those in young adult rats (100 days). In untreated control teeth, immunoreactivity for intense heat-shock protein (HSP)-25 and nestin was found in odontoblasts, whereas class-II-MHC-positive cells were densely distributed in the periphery of the pulp. Cavity preparation caused two types of pulpal reactions based on the different extent of damage in the aged rats. In the case of severe damage, destruction of the odontoblast layer was conspicuous at the affected site. By 12 h after cavity preparation, numerous class-II-MHC-positive cells appeared along the pulp-dentin border but subsequently disappeared together with HSP-25-immunopositive cells, and finally newly differentiated odontoblast-like cells took the place of the degenerated odontoblasts and acquired immunoreactivity for HSP-25 and nestin by postoperative day 3. In the case of mild damage, no remarkable changes occurred in odontoblasts after operation, and some survived through the experimental stages. These findings indicate that aged pulp tissue still possesses a defense capacity, and that a variety of reactions can occur depending on the difference in the status of dentinal tubules and/or odontoblast processes in individuals.

  3. Culture medium modulates the behaviour of human dental pulp-derived cells: Technical Note

    Directory of Open Access Journals (Sweden)

    S Lopez-Cazaux

    2006-02-01

    Full Text Available In vitro approaches have extensively been developed to study reparative dentinogenesis. While dental pulp is a source of unidentified progenitors able to differentiate into odontoblast-like cells, we investigated the effect of two media; MEM (1.8mM Ca and 1mM Pi and RPMI 1640 (0.8mM Ca and 5mM Pi on the behaviour of human dental pulp cells. Our data indicate that MEM significantly increased cell proliferation and markedly enhanced the proportion of -smooth muscle actin positive cells, which represent a putative source of progenitors able to give rise to odontoblast-like cells. In addition, MEM strongly stimulated alkaline phosphatase activity and was found to induce expression of transcripts encoding dentin sialophosphoprotein, an odontoblastic marker, without affecting that of parathyroid hormone/parathyroid hormone related protein-receptor and osteonectin. In conclusion, these observations demonstrate that not only proliferation but also differentiation into odontoblast-like cells was induced by rich calcium and poor phosphate medium (MEM as compared to RPMI 1640. This study provides important data for the determination of the optimal culture conditions allowing odontoblast-like differentiation in human pulp cell culture.

  4. The influence of social psychological factors on behaviour, stress and dose in Chernobyl affected areas

    International Nuclear Information System (INIS)

    Murphy, M.; Allen, P.

    1998-01-01

    During the 12 years since the Chernobyl nuclear accident, people in the affected areas have lived day to day with the risks of radiation. During these 12 years many countermeasures have been applied to minimise dose and thus reduce the threat to the health of the affected populations. Some of these countermeasures are aimed at changing daily life; for example, advice and restrictions on behaviours relating to the forest, consumption of forest produce and the consumption of private milk. In order to be effective, these countermeasures require action, or compliance, on the part of the affected populations. How have people in these areas responded to this risk and to the countermeasures employed to minimise the risk? A number of social psychological factors may be involved in peoples responses to this situation, including their perceptions of threat, the perceived costs and benefits of the behaviours involved, and the influence of other people. We examine the influence of these various social psychological factors on compliance behaviour, dose, and stress related health through a survey of people in the affected areas using quantitative questionnaire measures. SPARPA or Social psychological aspects of radiation protection after accidents, is a European Commission-sponsored project (F14C-CT96-0010) involving U. Surrey, Symlog and NRPB as well as partners in the CIS. Specific objectives include: to characterise, using quantitative methods, the nature and psychological impact of countermeasures and the influence of behaviour on dose, and to develop, guidance on the implementation of countermeasures, taking account of the social and psychological context. (authors)

  5. Fluoxetine Dose and Administration Method Differentially Affect Hippocampal Plasticity in Adult Female Rats

    Science.gov (United States)

    Pawluski, Jodi L.; van Donkelaar, Eva; Abrams, Zipporah; Steinbusch, Harry W. M.; Charlier, Thierry D.

    2014-01-01

    Selective serotonin reuptake inhibitor medications are one of the most common treatments for mood disorders. In humans, these medications are taken orally, usually once per day. Unfortunately, administration of antidepressant medications in rodent models is often through injection, oral gavage, or minipump implant, all relatively stressful procedures. The aim of the present study was to investigate how administration of the commonly used SSRI, fluoxetine, via a wafer cookie, compares to fluoxetine administration using an osmotic minipump, with regards to serum drug levels and hippocampal plasticity. For this experiment, adult female Sprague-Dawley rats were divided over the two administration methods: (1) cookie and (2) osmotic minipump and three fluoxetine treatment doses: 0, 5, or 10 mg/kg/day. Results show that a fluoxetine dose of 5 mg/kg/day, but not 10 mg/kg/day, results in comparable serum levels of fluoxetine and its active metabolite norfluoxetine between the two administration methods. Furthermore, minipump administration of fluoxetine resulted in higher levels of cell proliferation in the granule cell layer (GCL) at a 5 mg dose compared to a 10 mg dose. Synaptophysin expression in the GCL, but not CA3, was significantly lower after fluoxetine treatment, regardless of administration method. These data suggest that the administration method and dose of fluoxetine can differentially affect hippocampal plasticity in the adult female rat. PMID:24757568

  6. Fluoxetine Dose and Administration Method Differentially Affect Hippocampal Plasticity in Adult Female Rats

    Directory of Open Access Journals (Sweden)

    Jodi L. Pawluski

    2014-01-01

    Full Text Available Selective serotonin reuptake inhibitor medications are one of the most common treatments for mood disorders. In humans, these medications are taken orally, usually once per day. Unfortunately, administration of antidepressant medications in rodent models is often through injection, oral gavage, or minipump implant, all relatively stressful procedures. The aim of the present study was to investigate how administration of the commonly used SSRI, fluoxetine, via a wafer cookie, compares to fluoxetine administration using an osmotic minipump, with regards to serum drug levels and hippocampal plasticity. For this experiment, adult female Sprague-Dawley rats were divided over the two administration methods: (1 cookie and (2 osmotic minipump and three fluoxetine treatment doses: 0, 5, or 10 mg/kg/day. Results show that a fluoxetine dose of 5 mg/kg/day, but not 10 mg/kg/day, results in comparable serum levels of fluoxetine and its active metabolite norfluoxetine between the two administration methods. Furthermore, minipump administration of fluoxetine resulted in higher levels of cell proliferation in the granule cell layer (GCL at a 5 mg dose compared to a 10 mg dose. Synaptophysin expression in the GCL, but not CA3, was significantly lower after fluoxetine treatment, regardless of administration method. These data suggest that the administration method and dose of fluoxetine can differentially affect hippocampal plasticity in the adult female rat.

  7. The study of mean glandular dose in mammography in Yazd and the factors affecting it

    International Nuclear Information System (INIS)

    Bouzarjomehri, F.; Mostaar, A.; Ghasemi, A.; Ehramposh, M. H.; Khosravi, H.

    2006-01-01

    The objective of this study was to determine the mean glandular dose resulting from mammography examinations in Yazd, southeastern Iran and to identify the factors affecting it. Patients and Methods: This survey was conducted during May to December 2005 to estimate the mean glandular dose for women undergoing mammography and to report the distribution of dose. compressed breast thickness, glandular tissue content, and mammography technique used. The clinical data were collected from 946 mammograms taken from 246 women who were referred to four mammography centers. The mammography instruments in these centers were four modern units with a molybdenum anode and either molybdenum or rhodium filter. The exposure conditions of each mammogram were recorded. The breast glandular content of each mammogram was estimated by a radiologist. The mean glandular dose was calculated based on measuring the normalized entrance skin dose in air. half value layer, kVp, mAs, breast thickness and glandular content. Half value layer, kVp and entrance skin dose were measured by a solid-state detector. The analytical method of Sobol et al. was used for calculation of mean glandular dose . Results: The mean±SD mean glandular dose per film was.2±0.6 mGy for cranio caudal and 1.63±O.9 mGy for mediolateral oblique views. The mean±SD mean glandular dose per woman was 5.5 3.1.mGy. A positive correlation was found between the beam Half value layer with mean glandular dose (r=O.38) and the breast thickness with mean glandular dose (r=O.5). Conclusion: The mean±SD mean glandular dose per film of 1.42±0.8 mGy in present study was lower than most of similar reports. However, the mean mean glandular dose per woman was higher than that in other studies

  8. Processing of facial affect in social drinkers: a dose-response study of alcohol using dynamic emotion expressions.

    Science.gov (United States)

    Kamboj, Sunjeev K; Joye, Alyssa; Bisby, James A; Das, Ravi K; Platt, Bradley; Curran, H Valerie

    2013-05-01

    Studies of affect recognition can inform our understanding of the interpersonal effects of alcohol and help develop a more complete neuropsychological profile of this drug. The objective of the study was to examine affect recognition in social drinkers using a novel dynamic affect-recognition task, sampling performance across a range of evolutionarily significant target emotions and neutral expressions. Participants received 0, 0.4 or 0.8 g/kg alcohol in a double-blind, independent groups design. Relatively naturalistic changes in facial expression-from neutral (mouth open) to increasing intensities of target emotions, as well as neutral (mouth closed)-were simulated using computer-generated dynamic morphs. Accuracy and reaction time were measured and a two-high-threshold model applied to hits and false-alarm data to determine sensitivity and response bias. While there was no effect on the principal emotion expressions (happiness, sadness, fear, anger and disgust), compared to those receiving 0.8 g/kg of alcohol and placebo, participants administered with 0.4 g/kg alcohol tended to show an enhanced response bias to neutral expressions. Exploration of this effect suggested an accompanying tendency to misattribute neutrality to sad expressions following the 0.4-g/kg dose. The 0.4-g/kg alcohol-but not 0.8 g/kg-produced a limited and specific modification in affect recognition evidenced by a neutral response bias and possibly an accompanying tendency to misclassify sad expressions as neutral. In light of previous findings on involuntary negative memory following the 0.4-g/kg dose, we suggest that moderate-but not high-doses of alcohol have a special relevance to emotional processing in social drinkers.

  9. Relationship between Individual External Doses, Ambient Dose Rates and Individuals' Activity-Patterns in Affected Areas in Fukushima following the Fukushima Daiichi Nuclear Power Plant Accident.

    Directory of Open Access Journals (Sweden)

    Wataru Naito

    Full Text Available The accident at Fukushima Daiichi Nuclear Power Plant on March 11, 2011, released radioactive material into the atmosphere and contaminated the land in Fukushima and several neighboring prefectures. Five years after the nuclear disaster, the radiation levels have greatly decreased due to physical decay, weathering, and decontamination operations in Fukushima. The populations of 12 communities were forced to evacuate after the accident; as of March 2016, the evacuation order has been lifted in only a limited area, and permanent habitation is still prohibited in most of the areas. In order for the government to lift the evacuation order and for individuals to return to their original residential areas, it is important to assess current and future realistic individual external doses. Here, we used personal dosimeters along with the Global Positioning System and Geographic Information System to understand realistic individual external doses and to relate individual external doses, ambient doses, and activity-patterns of individuals in the affected areas in Fukushima. The results showed that the additional individual external doses were well correlated to the additional ambient doses based on the airborne monitoring survey. The results of linear regression analysis suggested that the additional individual external doses were on average about one-fifth that of the additional ambient doses. The reduction factors, which are defined as the ratios of the additional individual external doses to the additional ambient doses, were calculated to be on average 0.14 and 0.32 for time spent at home and outdoors, respectively. Analysis of the contribution of various activity patterns to the total individual external dose demonstrated good agreement with the average fraction of time spent daily in each activity, but the contribution due to being outdoors varied widely. These results are a valuable contribution to understanding realistic individual external doses

  10. Does the dose-solubility ratio affect the mean dissolution time of drugs?

    Science.gov (United States)

    Lánský, P; Weiss, M

    1999-09-01

    To present a new model for describing drug dissolution. On the basis of the new model to characterize the dissolution profile by the distribution function of the random dissolution time of a drug molecule, which generalizes the classical first order model. Instead of assuming a constant fractional dissolution rate, as in the classical model, it is considered that the fractional dissolution rate is a decreasing function of the dissolved amount controlled by the dose-solubility ratio. The differential equation derived from this assumption is solved and the distribution measures (half-dissolution time, mean dissolution time, relative dispersion of the dissolution time, dissolution time density, and fractional dissolution rate) are calculated. Finally, instead of monotonically decreasing the fractional dissolution rate, a generalization resulting in zero dissolution rate at time origin is introduced. The behavior of the model is divided into two regions defined by q, the ratio of the dose to the solubility level: q 1 (saturation of the solution, saturation time). The singular case q = 1 is also treated and in this situation the mean as well as the relative dispersion of the dissolution time increase to infinity. The model was successfully fitted to data (1). This empirical model is descriptive without detailed physical reasoning behind its derivation. According to the model, the mean dissolution time is affected by the dose-solubility ratio. Although this prediction appears to be in accordance with preliminary application, further validation based on more suitable experimental data is required.

  11. Influence of valproate on the required dose of propofol for anesthesia during electroconvulsive therapy of bipolar affective disorder patients

    Directory of Open Access Journals (Sweden)

    Hızlı Sayar G

    2014-03-01

    Full Text Available Gökben Hizli Sayar, Gül Eryilmaz, Siban Şemieoğlu, Eylem Özten, Işil Göğcegöz Gül Uskudar University, Neuropsychiatry Istanbul Hospital, Istanbul, Turkey Background: Propofol is often used as an anesthetic agent for electroconvulsive therapy (ECT. In recent studies, propofol was shown to possess significant seizure-shortening properties during ECT. "Valproate" is a mood stabilizer used mainly in the treatment of bipolar affective disorder. It is reported that valproate, being an anticonvulsant, raises the seizure threshold, thus decreases the efficacy of ECT treatment. Aim: The purpose of our study was to compare the dose of propofol in valproate-using patients and valproate-free patients. Methods: In an open design, 17 patients with bipolar affective disorder manic episodes who were to be treated with valproate and ECT in combination, were compared with 16 manic-episode patients who were to be treated with ECT but not valproate. The two groups were compared on the basis of electroencephalography-registered seizure duration and the propofol dosage required to induce anesthesia. Results: Valproate, compared with no valproate treatment, results in a decrease in the propofol dose required to induce anesthesia. In the valproate group of study participants, seizure duration was significantly shorter than in the valproate-free group. Conclusion: The results suggest that valproate reduces the dose of propofol required for anesthesia during ECT treatment in patients with bipolar affective disorder manic episodes. Although propofol is a safe and efficacious anesthetic for ECT treatment, lower doses of propofol should be used to induce anesthesia for patients under valproate treatment. When the clinician needs to prolong seizure duration in patients treated with valproate, interruption of the valproate treatment or an anesthetic agent other than propofol should be considered. Keywords: bipolar affective disorder, ECT, anticonvulsant, mood

  12. Milnacipran affects mouse impulsive, aggressive, and depressive-like behaviors in a distinct dose-dependent manner

    Directory of Open Access Journals (Sweden)

    Iku Tsutsui-Kimura

    2017-07-01

    Full Text Available Serotonin/noradrenaline reuptake inhibitors (SNRIs are widely used for the treatment for major depressive disorder, but these drugs induce several side effects including increased aggression and impulsivity, which are risk factors for substance abuse, criminal involvement, and suicide. To address this issue, milnacipran (0, 3, 10, or 30 mg/kg, an SNRI and antidepressant, was intraperitoneally administered to mice prior to the 3-choice serial reaction time task, resident–intruder test, and forced swimming test to measure impulsive, aggressive, and depressive-like behaviors, respectively. A milnacipran dose of 10 mg/kg suppressed all behaviors, which was accompanied by increased dopamine and serotonin levels in the medial prefrontal cortex (mPFC but not in the nucleus accumbens (NAc. Although the most effective dose for depressive-like behavior was 30 mg/kg, the highest dose increased aggressive behavior and unaffected impulsive behavior. Increased dopamine levels in the NAc could be responsible for the effects. In addition, the mice basal impulsivity was negatively correlated with the latency to the first agonistic behavior. Thus, the optimal dose range of milnacipran is narrower than previously thought. Finding drugs that increase serotonin and dopamine levels in the mPFC without affecting dopamine levels in the NAc is a potential strategy for developing novel antidepressants.

  13. Study of the parameters affecting operator doses in interventional radiology using Monte Carlo simulations

    International Nuclear Information System (INIS)

    Koukorava, C.; Carinou, E.; Ferrari, P.; Krim, S.; Struelens, L.

    2011-01-01

    Measurements performed within the ORAMED project helped to evaluate the dose levels to the operators’ hands, wrists, legs and eye lenses, during several types of interventional radiology (IR) and cardiology (IC) procedures, and also to determine the parameters that affect the doses. However, the study of the effect of each parameter separately, was possible only through Monte Carlo (MC) simulations, as in clinical practice many of those parameters change simultaneously. The influence of the protective equipment, the beam projections, the beam quality, the field size and the position of the operator according to the position of access of the catheter was investigated, using anthropomorphic phantoms in setups that represent realistic IR/IC procedures. The proper use of protective shields was found to be the most important way of reducing extremity and eye lens exposure during such examinations. Ceiling suspended shields can reduce the doses to the eye lenses up to 97%, but they can also reduce hand doses about 70% when placed correctly. The highest exposure to the operator is observed for left anterior oblique (LAO) and cranial projections. Additionally, for overcouch irradiations the eyes and the hands are about 6 times more exposed compared to the cases where the tube is below the operating table. For the lateral LAO projection, placing the ceiling suspended shield at the left side of the operator is twice more effective for the protection of the eyes compared to the cases where it is placed above the patient. Finally, beam collimation was found to play an important role in the reduction of the hands and wrists doses, especially when the operator is close to the irradiation field.

  14. The effect of adriamycin on dentinogenesis and 3H-thymidine incorporation into the enamel organ of the rat incisor

    International Nuclear Information System (INIS)

    Karim, A.C.

    1990-01-01

    The effect of adriamycin (5 mg/kg) on 3 H-thymidine incorporation and on dentin formation was studied in rat incisors. Male Sprague Dawley rats received an intravenous injection of adriamycin. Some of these also received a subcutaneous injection of 3 H-thymidine at a dose of 2 mCi/kg one day later. One group of control animals received an intravenous injection of a volume of physiological saline equal to that of the adriamycin dose. Another group received physiological saline, and one hour later was given an additional injection of 3 H-thymidine at a similar dose as above. All the animals were killed 1 h, 1 d, 4 d, 8 d, 16 d, 28 d, and 32 d after 3 H-thymidine treatment. Light microscopy revealed irregular dentin deposits between the mantle and circumpulpal layer of the labial dentin at 16 d. Within these deposits were trapped cells. The latter, through radioautographic labelling, appeared to be cells from the odontoblast layer. Also, the labelling pattern of the enamel organ in both the control and experimental groups indicated that the eruption rate of the tooth was not affected. Serial sectioning and examination of the lingual portion of the incisors at 28 d revealed a lack of dentin formation and a failure in the closure of the apical foramen. Electron microscopic observations showed an irregular and random arrangement of collagen fibers within the deposits of irregular dentin, and the presence of twisted odontoblastic processes. Examination of the lingual surface showed the presence of fibroblasts and collagen fibers bridging the gap that resulted from the failure in dentin formation. These cells, which were similar to periodontal ligament cells, appeared to have arisen from that area. (author)

  15. Evaluation of dose from external irradiation for individuals living in areas affected by the Fukushima Daiichi nuclear plant accident

    International Nuclear Information System (INIS)

    Naito, Wataru; Uesaka, Motoki; Yamada, Chie; Ishii, Hideki

    2015-01-01

    In order to effectively and appropriately manage external radiation doses in the affected areas of Fukushima, it is important to identify when, where and how much exposure occurred. It is also necessary to quantitatively measure external exposure and air dose rates for different activity patterns in individuals living and working in Japanese-style buildings. The authors used a new personal dosemeter (D-shuttle) along with a global positioning system and geographical information system to relate personal dose rate with activity patterns and air dose rate. Hourly individual doses obtained by D-shuttle can provide an effective communication tool for those who want to identify when and how much exposure occurs. Personal monitoring of 26 volunteers showed that personal doses obtained from D-shuttle were ∼30 % of cumulative air dose estimated by data from the airborne monitoring survey. This analysis showed that, for most study volunteers, the exposure from staying at home represented about half of the total cumulative dose. This suggests that even though the peak exposure doses may be observed outside of working hours, to develop appropriate countermeasures for external dose reduction, it is thus important to identify the contributions of individuals' time-activities. This study provides a valuable basis for developing a realistic and pragmatic method to estimate external doses of individuals in Fukushima. (authors)

  16. Repeated low-dose exposures to sarin, soman, or VX affect acoustic startle in guinea pigs.

    Science.gov (United States)

    Smith, C D; Lee, R B; Moran, A V; Sipos, M L

    2016-01-01

    Chemical warfare nerve agents (CWNAs) are known to cause behavioral abnormalities in cases of human exposures and in animal models. The behavioral consequences of single exposures to CWNAs that cause observable toxic signs are particularly well characterized in animals; however, less is known regarding repeated smaller exposures that may or may not cause observable toxic signs. In the current study, guinea pigs were exposed to fractions (0.1, 0.2, or 0.4) of a medial lethal dose (LD50) of sarin, soman, or VX for two weeks. On each exposure day, and for a post-exposure period, acoustic startle response (ASR) was measured in each animal. Although relatively few studies use guinea pigs to measure behavior, this species is ideal for CWNA-related experiments because their levels of carboxylesterases closely mimic those of humans, unlike rats or mice. Results showed that the 0.4 LD50 doses of soman and VX transiently increased peak startle amplitude by the second week of injections, with amplitude returning to baseline by the second week post-exposure. Sarin also increased peak startle amplitude independent of week. Latencies to peak startle and PPI were affected by agent exposure but not consistently among the three agents. Most of the changes in startle responses returned to baseline following the cessation of exposures. These data suggest that doses of CWNAs not known to produce observable toxic signs in guinea pigs can affect behavior in the ASR paradigm. Further, these deficits are transient and usually return to baseline shortly after the end of a two-week exposure period. Published by Elsevier Inc.

  17. A systematic study on factors affecting patient dose, 2

    International Nuclear Information System (INIS)

    Otsuka, Akiyoshi; Higashida, Yoshiharu; Utsumi, Hiromoto; Ota, Masaji; Nakanishi, Takashi

    1979-01-01

    In the preceding report, we dealt with the field size and the tube voltage. This paper covers the differences in patient dose due to the focus to film distance (FFD), the patient thickness and whether the grid is used or not. Regarding the FFD, 100 cm is most commonly employed except in X-ray examinations of the chest, but from the viewpoint of the patient dose, this requires special consideration as to whether there is any theoretical basis for it. The patient thickness has a great bearing on the patient dose, but there is an individual difference, and it is almost impossible to change it artificially. However, there has been no detailed report on the relation between the patient thickness and the patient dose, therefore, this report treats of such relationship as well. Concerning the grid, consideration is given to the exposure times (Bucky factor). (author)

  18. Milnacipran affects mouse impulsive, aggressive, and depressive-like behaviors in a distinct dose-dependent manner.

    Science.gov (United States)

    Tsutsui-Kimura, Iku; Ohmura, Yu; Yoshida, Takayuki; Yoshioka, Mitsuhiro

    2017-07-01

    Serotonin/noradrenaline reuptake inhibitors (SNRIs) are widely used for the treatment for major depressive disorder, but these drugs induce several side effects including increased aggression and impulsivity, which are risk factors for substance abuse, criminal involvement, and suicide. To address this issue, milnacipran (0, 3, 10, or 30 mg/kg), an SNRI and antidepressant, was intraperitoneally administered to mice prior to the 3-choice serial reaction time task, resident-intruder test, and forced swimming test to measure impulsive, aggressive, and depressive-like behaviors, respectively. A milnacipran dose of 10 mg/kg suppressed all behaviors, which was accompanied by increased dopamine and serotonin levels in the medial prefrontal cortex (mPFC) but not in the nucleus accumbens (NAc). Although the most effective dose for depressive-like behavior was 30 mg/kg, the highest dose increased aggressive behavior and unaffected impulsive behavior. Increased dopamine levels in the NAc could be responsible for the effects. In addition, the mice basal impulsivity was negatively correlated with the latency to the first agonistic behavior. Thus, the optimal dose range of milnacipran is narrower than previously thought. Finding drugs that increase serotonin and dopamine levels in the mPFC without affecting dopamine levels in the NAc is a potential strategy for developing novel antidepressants. Copyright © 2017 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  19. LD-aminopterin in the canine homologue of human atopic dermatitis: a randomized, controlled trial reveals dosing factors affecting optimal therapy.

    Science.gov (United States)

    Zebala, John A; Mundell, Alan; Messinger, Linda; Griffin, Craig E; Schuler, Aaron D; Kahn, Stuart J

    2014-01-01

    Options are limited for patients with atopic dermatitis (AD) who do not respond to topical treatments. Antifolate therapy with systemic methotrexate improves the disease, but is associated with adverse effects. The investigational antifolate LD-aminopterin may offer improved safety. It is not known how antifolate dose and dosing frequency affect efficacy in AD, but a primary mechanism is thought to involve the antifolate-mediated accumulation of 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR). However, recent in vitro studies indicate that AICAR increases then decreases as a function of antifolate concentration. To address this issue and understand how dosing affects antifolate efficacy in AD, we examined the efficacy and safety of different oral doses and schedules of LD-aminopterin in the canine model of AD. This was a multi-center, double-blind trial involving 75 subjects with canine AD randomized to receive up to 12 weeks of placebo, once-weekly (0.007, 0.014, 0.021 mg/kg) or twice-weekly (0.007 mg/kg) LD-aminopterin. The primary efficacy outcome was the Global Score (GS), a composite of validated measures of disease severity and itch. GS improved in all once-weekly cohorts, with 0.014 mg/kg being optimal and significant (43%, P<0.01). The majority of improvement was seen by 8 weeks. In contrast, GS in the twice-weekly cohort was similar to placebo and worse than all once-weekly cohorts. Adverse events were similar across all treated cohorts and placebo. Once-weekly LD-aminopterin was safe and efficacious in canine AD. Twice-weekly dosing negated efficacy despite having the same daily and weekly dose as effective once-weekly regimens. Optimal dosing in this homologue of human AD correlated with the concentration-selective accumulation of AICAR in vitro, consistent with AICAR mediating LD-aminopterin efficacy in AD.

  20. LD-aminopterin in the canine homologue of human atopic dermatitis: a randomized, controlled trial reveals dosing factors affecting optimal therapy.

    Directory of Open Access Journals (Sweden)

    John A Zebala

    Full Text Available Options are limited for patients with atopic dermatitis (AD who do not respond to topical treatments. Antifolate therapy with systemic methotrexate improves the disease, but is associated with adverse effects. The investigational antifolate LD-aminopterin may offer improved safety. It is not known how antifolate dose and dosing frequency affect efficacy in AD, but a primary mechanism is thought to involve the antifolate-mediated accumulation of 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR. However, recent in vitro studies indicate that AICAR increases then decreases as a function of antifolate concentration. To address this issue and understand how dosing affects antifolate efficacy in AD, we examined the efficacy and safety of different oral doses and schedules of LD-aminopterin in the canine model of AD.This was a multi-center, double-blind trial involving 75 subjects with canine AD randomized to receive up to 12 weeks of placebo, once-weekly (0.007, 0.014, 0.021 mg/kg or twice-weekly (0.007 mg/kg LD-aminopterin. The primary efficacy outcome was the Global Score (GS, a composite of validated measures of disease severity and itch. GS improved in all once-weekly cohorts, with 0.014 mg/kg being optimal and significant (43%, P<0.01. The majority of improvement was seen by 8 weeks. In contrast, GS in the twice-weekly cohort was similar to placebo and worse than all once-weekly cohorts. Adverse events were similar across all treated cohorts and placebo.Once-weekly LD-aminopterin was safe and efficacious in canine AD. Twice-weekly dosing negated efficacy despite having the same daily and weekly dose as effective once-weekly regimens. Optimal dosing in this homologue of human AD correlated with the concentration-selective accumulation of AICAR in vitro, consistent with AICAR mediating LD-aminopterin efficacy in AD.

  1. Objective factors affecting the image quality of low-dose cranial CT of infant

    International Nuclear Information System (INIS)

    Xie Na; Gan Yungen; Wang Hongwei; Zeng Hongwu; Cao Weiguo; Sun Longwei

    2010-01-01

    Objective: To investigate the objective factors that affect the image quality of infant cranial CT using different mAs. Materials and Methods: Ninety infants were divided into three groups randomly. The maximum anteroposterior diameter (MAPD) of skull of each infant was measured. Three reference levels, cerebellar, basal ganglia and centrum semiovale levels were selected respectively. Only one level was studied in each group and scanned with 150, 100 and 80 mAs. The subjective quality grade and the objective noise of all images were recorded and analysed statistically. Results: The average MAPD of ninety patients was (148.0±17.4) mm. On the cerebellar level, the subjective quality grade was lower than the other two levels, which were 6.3%, 9.4% and 22.9% respectively when mAs were 150, 100 and 80 mAs. Both quality grade of image and objective noise were significantly correlated with MAPD. Conclusions: The inherent high noise of cerebellar level and MAPD were the objective factors that affect the image quality of low-dose cranial CT of infant. (authors)

  2. Outdoor γ-ray dose rate in Shariki Village and environmental factors affecting outdoor γ-ray dose rate in IES

    International Nuclear Information System (INIS)

    Iyogi, Takashi; Hisamatsu, Shun'ichi; Inaba, Jiro

    2000-01-01

    Previously, we surveyed the outdoor γ-ray dose rate throughout Aomori Prefecture from 1992 to 1995, and found an annual mean dose rate of 51 nGy h -1 . Relatively high dose rates were also observed in several areas (municipalities) of the survey locations. In this study, we examined the detailed distribution of the γ-ray dose rate in one such high dose rate area, Shariki Village. Glass dosemeters were used for the monitoring of cumulative γ-ray dose rate at 10 locations in the village. The dose rate from each radioactive nuclide in the ground at the monitoring locations was measured by using an in situ γ-ray spectrometer with a Ge detector. The results obtained with the glass dosemeters showed that the γ-ray dose rates in Shariki Village varied from 49 to 55 nGy h -1 . Although the dose rates were generally higher than the mean dose in Aomori Prefecture (1992-1995), the rates were lower than other high dose rate areas which had already been measured. The in situ γ-ray spectrometry revealed that these relatively high dose rates were mainly caused by 40 K and Th series radionuclides in the village. The effect of meteorological conditions on the γ-ray dose rate was studied at a monitoring station in the IES site. The dose rate was continuously recorded by a DBM NaI(Tl) scintillation detector system. The mean dose rate obtained when precipitation was sensed was 27 nGy h -1 and higher than when no precipitation was sensed (25 nGy h -1 ). (author)

  3. Outdoor γ-ray dose rate in Mutsu city and environmental factors affecting outdoor γ-ray dose rate in IES

    International Nuclear Information System (INIS)

    Iyogi, Takashi; Hisamatsu, Shun'ichi; Inaba, Jiro

    2001-01-01

    Previously, we surveyed outdoor γ-ray dose rates throughout Aomori Prefecture from 1992 to 1995, and found a mean annual dose rate of 28 nGy h -1 . Relatively high dose rates were also observed in several areas (municipalities) of the survey locations. In this study, we examined the detailed distribution of the γ-ray dose rate in one such high dose rate area, Mutsu City. Glass dosemeters were used for the monitoring of cumulative γ-ray dose rate at 10 locations in the city. The dose rate from each radioactive nuclide in the ground at the monitoring locations was measured by using an in situ γ-ray spectrometer with a Ge detector. The results obtained with the glass dosemeters showed that the γ-ray dose rates in Mutsu City varied from 17 to 32 nGy h -1 . Although the dose rates were almost the same as the mean dose in Aomori Prefecture (1992-1995), the rates were lower than other high dose rate areas which had already been measured. The in situ γ-ray spectrometry revealed that these relatively high dose rates were mainly caused by 40 K and Th series radionuclides in the local ground. The effect of meteorological conditions on the γ-ray dose rate was studied at a monitoring station in the IES site. The dose rate was continuously recorded by a DBM NaI(Tl) scintillation detector system. The mean dose rate obtained when precipitation was sensed was 26 nGy h -1 and higher than when no precipitation was sensed (24 nGy h -1 ). (author)

  4. Factors affecting patient dose in diagnostic radiology

    International Nuclear Information System (INIS)

    Poletti, J.L.

    1985-01-01

    There are two stages in the X-ray image forming process; first the irradiation of the patient to produce the X-ray pattern in space, known as the primary radiological image, and second, the conversion of this pattern into a visible form. This report discusses the first stage and its interrelation with image quality and patient dose

  5. Quantitative analysis of biological responses to low dose-rate γ-radiation, including dose, irradiation time, and dose-rate

    International Nuclear Information System (INIS)

    Magae, J.; Furukawa, C.; Kawakami, Y.; Hoshi, Y.; Ogata, H.

    2003-01-01

    Full text: Because biological responses to radiation are complex processes dependent on irradiation time as well as total dose, it is necessary to include dose, dose-rate and irradiation time simultaneously to predict the risk of low dose-rate irradiation. In this study, we analyzed quantitative relationship among dose, irradiation time and dose-rate, using chromosomal breakage and proliferation inhibition of human cells. For evaluation of chromosome breakage we assessed micronuclei induced by radiation. U2OS cells, a human osteosarcoma cell line, were exposed to gamma-ray in irradiation room bearing 50,000 Ci 60 Co. After the irradiation, they were cultured for 24 h in the presence of cytochalasin B to block cytokinesis, cytoplasm and nucleus were stained with DAPI and propidium iodide, and the number of binuclear cells bearing micronuclei was determined by fluorescent microscopy. For proliferation inhibition, cells were cultured for 48 h after the irradiation and [3H] thymidine was pulsed for 4 h before harvesting. Dose-rate in the irradiation room was measured with photoluminescence dosimeter. While irradiation time less than 24 h did not affect dose-response curves for both biological responses, they were remarkably attenuated as exposure time increased to more than 7 days. These biological responses were dependent on dose-rate rather than dose when cells were irradiated for 30 days. Moreover, percentage of micronucleus-forming cells cultured continuously for more than 60 days at the constant dose-rate, was gradually decreased in spite of the total dose accumulation. These results suggest that biological responses at low dose-rate, are remarkably affected by exposure time, that they are dependent on dose-rate rather than total dose in the case of long-term irradiation, and that cells are getting resistant to radiation after the continuous irradiation for 2 months. It is necessary to include effect of irradiation time and dose-rate sufficiently to evaluate risk

  6. Experimentally studied dynamic dose interplay does not meaningfully affect target dose in VMAT SBRT lung treatments.

    Science.gov (United States)

    Stambaugh, Cassandra; Nelms, Benjamin E; Dilling, Thomas; Stevens, Craig; Latifi, Kujtim; Zhang, Geoffrey; Moros, Eduardo; Feygelman, Vladimir

    2013-09-01

    The effects of respiratory motion on the tumor dose can be divided into the gradient and interplay effects. While the interplay effect is likely to average out over a large number of fractions, it may play a role in hypofractionated [stereotactic body radiation therapy (SBRT)] treatments. This subject has been extensively studied for intensity modulated radiation therapy but less so for volumetric modulated arc therapy (VMAT), particularly in application to hypofractionated regimens. Also, no experimental study has provided full four-dimensional (4D) dose reconstruction in this scenario. The authors demonstrate how a recently described motion perturbation method, with full 4D dose reconstruction, is applied to describe the gradient and interplay effects during VMAT lung SBRT treatments. VMAT dose delivered to a moving target in a patient can be reconstructed by applying perturbations to the treatment planning system-calculated static 3D dose. Ten SBRT patients treated with 6 MV VMAT beams in five fractions were selected. The target motion (motion kernel) was approximated by 3D rigid body translation, with the tumor centroids defined on the ten phases of the 4DCT. The motion was assumed to be periodic, with the period T being an average from the empirical 4DCT respiratory trace. The real observed tumor motion (total displacement ≤ 8 mm) was evaluated first. Then, the motion range was artificially increased to 2 or 3 cm. Finally, T was increased to 60 s. While not realistic, making T comparable to the delivery time elucidates if the interplay effect can be observed. For a single fraction, the authors quantified the interplay effect as the maximum difference in the target dosimetric indices, most importantly the near-minimum dose (D99%), between all possible starting phases. For the three- and five-fractions, statistical simulations were performed when substantial interplay was found. For the motion amplitudes and periods obtained from the 4DCT, the interplay effect

  7. Experimentally studied dynamic dose interplay does not meaningfully affect target dose in VMAT SBRT lung treatments

    International Nuclear Information System (INIS)

    Stambaugh, Cassandra; Nelms, Benjamin E.; Dilling, Thomas; Stevens, Craig; Latifi, Kujtim; Zhang, Geoffrey; Moros, Eduardo; Feygelman, Vladimir

    2013-01-01

    Purpose: The effects of respiratory motion on the tumor dose can be divided into the gradient and interplay effects. While the interplay effect is likely to average out over a large number of fractions, it may play a role in hypofractionated [stereotactic body radiation therapy (SBRT)] treatments. This subject has been extensively studied for intensity modulated radiation therapy but less so for volumetric modulated arc therapy (VMAT), particularly in application to hypofractionated regimens. Also, no experimental study has provided full four-dimensional (4D) dose reconstruction in this scenario. The authors demonstrate how a recently described motion perturbation method, with full 4D dose reconstruction, is applied to describe the gradient and interplay effects during VMAT lung SBRT treatments.Methods: VMAT dose delivered to a moving target in a patient can be reconstructed by applying perturbations to the treatment planning system-calculated static 3D dose. Ten SBRT patients treated with 6 MV VMAT beams in five fractions were selected. The target motion (motion kernel) was approximated by 3D rigid body translation, with the tumor centroids defined on the ten phases of the 4DCT. The motion was assumed to be periodic, with the period T being an average from the empirical 4DCT respiratory trace. The real observed tumor motion (total displacement ≤8 mm) was evaluated first. Then, the motion range was artificially increased to 2 or 3 cm. Finally, T was increased to 60 s. While not realistic, making T comparable to the delivery time elucidates if the interplay effect can be observed. For a single fraction, the authors quantified the interplay effect as the maximum difference in the target dosimetric indices, most importantly the near-minimum dose (D 99% ), between all possible starting phases. For the three- and five-fractions, statistical simulations were performed when substantial interplay was found.Results: For the motion amplitudes and periods obtained from the

  8. Experimentally studied dynamic dose interplay does not meaningfully affect target dose in VMAT SBRT lung treatments

    Energy Technology Data Exchange (ETDEWEB)

    Stambaugh, Cassandra [Department of Physics, University of South Florida, Tampa, Florida 33612 (United States); Nelms, Benjamin E. [Canis Lupus LLC, Merrimac, Wisconsin 53561 (United States); Dilling, Thomas; Stevens, Craig; Latifi, Kujtim; Zhang, Geoffrey; Moros, Eduardo; Feygelman, Vladimir [Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida 33612 (United States)

    2013-09-15

    Purpose: The effects of respiratory motion on the tumor dose can be divided into the gradient and interplay effects. While the interplay effect is likely to average out over a large number of fractions, it may play a role in hypofractionated [stereotactic body radiation therapy (SBRT)] treatments. This subject has been extensively studied for intensity modulated radiation therapy but less so for volumetric modulated arc therapy (VMAT), particularly in application to hypofractionated regimens. Also, no experimental study has provided full four-dimensional (4D) dose reconstruction in this scenario. The authors demonstrate how a recently described motion perturbation method, with full 4D dose reconstruction, is applied to describe the gradient and interplay effects during VMAT lung SBRT treatments.Methods: VMAT dose delivered to a moving target in a patient can be reconstructed by applying perturbations to the treatment planning system-calculated static 3D dose. Ten SBRT patients treated with 6 MV VMAT beams in five fractions were selected. The target motion (motion kernel) was approximated by 3D rigid body translation, with the tumor centroids defined on the ten phases of the 4DCT. The motion was assumed to be periodic, with the period T being an average from the empirical 4DCT respiratory trace. The real observed tumor motion (total displacement ≤8 mm) was evaluated first. Then, the motion range was artificially increased to 2 or 3 cm. Finally, T was increased to 60 s. While not realistic, making T comparable to the delivery time elucidates if the interplay effect can be observed. For a single fraction, the authors quantified the interplay effect as the maximum difference in the target dosimetric indices, most importantly the near-minimum dose (D{sub 99%}), between all possible starting phases. For the three- and five-fractions, statistical simulations were performed when substantial interplay was found.Results: For the motion amplitudes and periods obtained from

  9. Genetic Factors Affecting Susceptibility to Low Dose & Low Dose-Rate Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bedford, Joel

    2014-04-18

    Our laboratory has, among other things, developed and used the gamma H2AX focus assay and other chromosomal and cell killing assays to show that differences in this DNA double strand break (dsb) related response can be clearly and distinctly demonstrated for cells which are mildly hyper-radiosensitive such as those associated with A-T heterozygosity. We have found this level of mild hypersensitivity for cells from some 20 to 30 % of apparently normal individuals and from apparently normal parents of Retinoblastoma patients. We found significant differences in gene expression in somatic cells from unaffected parents of Rb patients as compared with normal controls, suggesting that these parents may harbor some as yet unidentified genetic abnormality. In other experiments we sought to determine the extent of differences in normal human cellular reaponses to radiation depending on their irradiation in 2D monolayer vs 3D organized acinar growth conditions. We exmined cell reproductive death, chromosomal aberration induction, and the levels of γ-H2AX foci in cells after single acute gamma-ray doses and immediately after 20 hours of irradiation at a dose rate of 0.0017 Gy/min. We found no significant differences in the dose-responses of these cells under the 2D or 3D growth conditions. While this does not mean such differences cannot occur in other situations, it does mean that they do not generally or necessarily occur. In another series of studies in collaboration with Dr Chuan Li, with supprt from this current grant. We reported a role for apoptotic cell death in promoting wound healing and tissue regeneration in mice. Apoptotic cells released growth signals that stimulated the proliferation of progenitor or stem cells. In yet another collaboration with Dr, B. Chen with funds from this grant, the relative radiosensitivity to cell killing as well as chromosomal instability of 13 DNA-PKcs site-directed mutant cell lines (defective at phosphorylation sites or kinase

  10. Single therapeutic and supratherapeutic doses of sacubitril/valsartan (LCZ696) do not affect cardiac repolarization.

    Science.gov (United States)

    Langenickel, Thomas H; Jordaan, Pierre; Petruck, Jesika; Kode, Kiran; Pal, Parasar; Vaidya, Soniya; Chandra, Priya; Rajman, Iris

    2016-08-01

    Sacubitril/valsartan (LCZ696) is a first-in-class angiotensin receptor neprilysin inhibitor (ARNI) indicated to reduce the risk of cardiovascular death and hospitalization for heart failure in patients with chronic heart failure (NYHA class II-IV) and reduced ejection fraction. This study was aimed to evaluate the effect of single oral therapeutic (400 mg) and supratherapeutic (1200 mg) doses of LCZ696 on cardiac repolarization. This randomized double-blind crossover study in healthy male subjects compared the effect of therapeutic and supratherapeutic doses of LCZ696 with placebo and moxifloxacin 400 mg (open-label treatment) as positive control. The primary assessment was mean baseline- and placebo-corrected QTcF (∆∆QTcF; Fridericia correction). Additional assessments included the ∆∆QTcB (Bazett's correction), PR interval, QRS duration, heart rate (HR), LCZ696 pharmacokinetics, pharmacokinetic/pharmacodynamic relationships, and safety. Of the 84 subjects enrolled, 81 completed the study. The maximum upper bound of the two-sided 90 % confidence interval for ∆∆QTcF for LCZ696 400 mg and 1200 mg were <10 ms, and assay sensitivity was confirmed with moxifloxacin. No relevant treatment-emergent changes were observed in any of the ECG-derived parameters with LCZ696 or placebo, and the incidence of adverse events was comparable among the treatment groups. Single therapeutic and supratherapeutic doses of LCZ696 did not affect cardiac repolarization as defined by the E14 ICH guidelines.

  11. Dose/dose-rate responses of shrimp larvae to UV-B radiation

    International Nuclear Information System (INIS)

    Damkaer, D.M.

    1981-01-01

    Previous work indicated dose-rate thresholds in the effects of UV-B on the near-surface larvae of three shrimp species. Additional observations suggest that the total dose response varies with dose-rate. Below 0.002 Wm -2 sub([DNA]) irradiance no significant effect is noted in activity, development, or survival. Beyond that dose-rate threshold, shrimp larvae are significantly affected if the total dose exceeds about 85 Jm -2 sub([DNA]). Predictions cannot be made without both the dose-rate and the dose. These dose/dose-rate thresholds are compared to four-year mean dose/dose-rate solar UV-B irradiances at the experimental site, measured at the surface and calculated for 1 m depth. The probability that the shrimp larvae would receive lethal irradiance is low for the first half of the season of surface occurrence, even with a 44% increase in damaging UV radiation. (orig.)

  12. Dose/dose-rate responses of shrimp larvae to UV-B radiation

    Energy Technology Data Exchange (ETDEWEB)

    Damkaer, D.M.; Dey, D.B.; Heron, G.A.

    1981-01-01

    Previous work indicated dose-rate thresholds in the effects of UV-B on the near-surface larvae of three shrimp species. Additional observations suggest that the total dose response varies with dose-rate. Below 0.002 Wm/sup -2/sub((DNA)) irradiance no significant effect is noted in activity, development, or survival. Beyond that dose-rate threshold, shrimp larvae are significantly affected if the total dose exceeds about 85 Jm/sup -2/sub((DNA)). Predictions cannot be made without both the dose-rate and the dose. These dose/dose-rate thresholds are compared to four-year mean dose/dose-rate solar UV-B irradiances at the experimental site, measured at the surface and calculated for 1 m depth. The probability that the shrimp larvae would receive lethal irradiance is low for the first half of the season of surface occurrence, even with a 44% increase in damaging UV radiation.

  13. Effect of irradiation on the dental pulp tissues in streptozotocin-induced diabetic rats

    International Nuclear Information System (INIS)

    Kang, Ho Duk; Hwang, Eui Hwan; Lee, Sang Rae

    2005-01-01

    To observe the histological changes in the pulp tissues of mandibular molars in streptozotocin-induced diabetic rats after irradiation. The male Sprague-Dawley rats weighing approximately 250 gm were divided into four groups : control, diabetes, irradiation, and diabetes-irradiation groups. Diabetes mellitus was induced in the rats by injecting streptozotocin. Rats in control and irradiation groups were injected with citrate buffer only. After 5 days, the head and neck region of the rats in irradiation and diabetes-irradiation groups were irradiated with a single absorbed dose of 10 Gy. All the rats were sacrificed at 3, 7, 14, 21, and 28 days after irradiation. The specimen including the mandibular molars were sectioned and observed using a histopathological method. In the diabetes group, capillary dilatation was observed. However, there was no obvious morphologic alteration of the odontoblasts. In the irradiation group, generalized necrosis of the dental pulp tissues was observed. Vacuolation of the odontoblasts and dilatation of the capillaries were noted in the early experimental phases. In the diabetes-irradiation group, generalized degeneration of the dental pulp tissues was observed. Vacuolation of the dental pulp cells and the odontoblasts was noted in the late experimental phases. This experiment suggest that dilatation of the capillaries in the dental pulp tissue is induced by diabetic state, and generalized degeneration of the dental pulp tissues is induced by irradiation of the diabetic group.

  14. Overexpression of Receptor for Advanced Glycation End Products and High-Mobility Group Box 1 in Human Dental Pulp Inflammation

    Directory of Open Access Journals (Sweden)

    Salunya Tancharoen

    2014-01-01

    Full Text Available High mobility group box 1 (HMGB1, a nonhistone DNA-binding protein, is released into the extracellular space and promotes inflammation. HMGB1 binds to related cell signaling transduction receptors, including receptor for advanced glycation end products (RAGE, which actively participate in vascular and inflammatory diseases. The aim of this study was to examine whether RAGE and HMGB1 are involved in the pathogenesis of pulpitis and investigate the effect of Prevotella intermedia (P. intermedia lipopolysaccharide (LPS on RAGE and HMGB1 expression in odontoblast-like cells (OLC-1. RAGE and HMGB1 expression levels in clinically inflamed dental pulp were higher than those in healthy dental pulp. Upregulated expression of RAGE was observed in odontoblasts, stromal pulp fibroblasts-like cells, and endothelial-like cell lining human pulpitis tissue. Strong cytoplasmic HMGB1 immunoreactivity was noted in odontoblasts, whereas nuclear HMGB1 immunoreactivity was seen in stromal pulp fibroblasts-like cells in human pulpitis tissue. LPS stimulated OLC-1 cells produced HMGB1 in a dose-dependent manner through RAGE. HMGB1 translocation towards the cytoplasm and secretion from OLC-1 in response to LPS was inhibited by TPCA-1, an inhibitor of NF-κB activation. These findings suggest that RAGE and HMGB1 play an important role in the pulpal immune response to oral bacterial infection.

  15. Autoradiographic investigation of the effects of low-dose colchicine on dentinogenesis in rat incisors

    International Nuclear Information System (INIS)

    Oliveira Nogueira, T. de; Rossetini, S.M.

    1991-01-01

    Twelve wistar rats received 0.5 mg/kg colchicine (CLC) i.v. Three animals were sacrified 5 h, 24 h, 3 days and 7 days after the injection. Ninety minutes before sacrifice all animals received tritiated proline intraperitoneally. Autoradiograms of sections from the maxillary incisor were subjected to quantitative, and statistical analysis. These results revealed an increased secretory activity in the odontoblasts in the more incisal parts of the tooth, indicating a stimulatory effect of CLC on collagen production and secretion after 3 days. (author)

  16. Does Vertebroplasty Affect Radiation Dose Distribution?: Comparison of Spatial Dose Distributions in a Cement-Injected Vertebra as Calculated by Treatment Planning System and Actual Spatial Dose Distribution

    International Nuclear Information System (INIS)

    Komemushi, A.; Tanigawa, N.; Kariya, Sh.; Yagi, R.; Nakatani, M.; Suzuki, S.; Sano, A.; Ikeda, K.; Utsunomiya, K.; Harima, Y.; Sawada, S.

    2012-01-01

    Purpose. To assess differences in dose distribution of a vertebral body injected with bone cement as calculated by radiation treatment planning system (RTPS) and actual dose distribution. Methods. We prepared two water-equivalent phantoms with cement, and the other two phantoms without cement. The bulk density of the bone cement was imported into RTPS to reduce error from high CT values. A dose distribution map for the phantoms with and without cement was calculated using RTPS with clinical setting and with the bulk density importing. Actual dose distribution was measured by the film density. Dose distribution as calculated by RTPS was compared to the dose distribution measured by the film dosimetry. Results. For the phantom with cement, dose distribution was distorted for the areas corresponding to inside the cement and on the ventral side of the cement. However, dose distribution based on film dosimetry was undistorted behind the cement and dose increases were seen inside cement and around the cement. With the equivalent phantom with bone cement, differences were seen between dose distribution calculated by RTPS and that measured by the film dosimetry. Conclusion. The dose distribution of an area containing bone cement calculated using RTPS differs from actual dose distribution

  17. Balancing patient dose and image quality

    International Nuclear Information System (INIS)

    Martin, C.J.; Sutton, D.G.; Sharp, P.F.

    1999-01-01

    The formation of images in diagnostic radiology involves a complex interdependence of many factors. The ideal balance is to obtain an image which is adequate for the clinical purpose with the minimum radiation dose. Factors which affect radiation dose and image quality can be grouped under three headings; radiation quality, photon fluence and removal of scattered radiation. If optimal performance is to be achieved, it is necessary to understand how these factors influence image formation and affect radiation dose, and apply methodology for image quality and dose analysis at each stage in the development and use of X-ray equipment

  18. A single high dose of escitalopram increases mismatch negativity without affecting processing negativity or P300 amplitude in healthy volunteers

    DEFF Research Database (Denmark)

    Wienberg, M; Glenthøj, Birte Yding; Jensen, K S

    2009-01-01

    processing. The present study was designed to replicate and further extent the results of our initial study on the effects of a low dose of escitalopram (10 mg) on MMN, PN and P300 amplitude. In a randomised, double-blind, cross-over experiment, 20 healthy male volunteers received either a single, orally...... administered dose of 15 mg escitalopram (a highly selective serotonin reuptake inhibitor (SSRI)) or placebo, after which their PN, MMN and P300 amplitude were assessed. Similar to our initial study with 10 mg escitalopram, 15 mg escitalopram significantly increased MMN, while it did not affect P300 amplitude....... In contrast to our initial study, however, the currently higher dose of escitalopram did not increase PN. Results support the view that a broad range of increased serotonergic activity enhances MMN, while the relationship between serotonin and PN seems more complex. The current study does not support...

  19. Renal function affects absorbed dose to the kidneys and haematological toxicity during {sup 177}Lu-DOTATATE treatment

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, Johanna; Berg, Gertrud [Sahlgrenska University Hospital, Department of Oncology, Goeteborg (Sweden); Waengberg, Bo [Sahlgrenska University Hospital, Department of Surgery, Goeteborg (Sweden); Larsson, Maria [University of Gothenburg, Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy, Goeteborg (Sweden); Forssell-Aronsson, Eva; Bernhardt, Peter [University of Gothenburg, Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy, Goeteborg (Sweden); Sahlgrenska University Hospital, Department of Medical Physics and Medical Bioengineering, Goeteborg (Sweden)

    2015-05-01

    Peptide receptor radionuclide therapy (PRRT) has become an important treatment option in the management of advanced neuroendocrine tumours. Long-lasting responses are reported for a majority of treated patients, with good tolerability and a favourable impact on quality of life. The treatment is usually limited by the cumulative absorbed dose to the kidneys, where the radiopharmaceutical is reabsorbed and retained, or by evident haematological toxicity. The aim of this study was to evaluate how renal function affects (1) absorbed dose to the kidneys, and (2) the development of haematological toxicity during PRRT treatment. The study included 51 patients with an advanced neuroendocrine tumour who received {sup 177}Lu-DOTATATE treatment during 2006 - 2011 at Sahlgrenska University Hospital in Gothenburg. An average activity of 7.5 GBq (3.5 - 8.2 GBq) was given at intervals of 6 - 8 weeks on one to five occasions. Patient baseline characteristics according to renal and bone marrow function, tumour burden and medical history including prior treatment were recorded. Renal and bone marrow function were then monitored during treatment. Renal dosimetry was performed according to the conjugate view method, and the residence time for the radiopharmaceutical in the whole body was calculated. A significant correlation between inferior renal function before treatment and higher received renal absorbed dose per administered activity was found (p < 0.01). Patients with inferior renal function also experienced a higher grade of haematological toxicity during treatment (p = 0.01). The residence time of {sup 177}Lu in the whole body (range 0.89 - 3.0 days) was correlated with grade of haematological toxicity (p = 0.04) but not with renal absorbed dose (p = 0.53). Patients with inferior renal function were exposed to higher renal absorbed dose per administered activity and developed a higher grade of haematological toxicity during {sup 177}Lu-DOTATATE treatment. The study confirms the

  20. The development of enamel tubules during the formation of enamel in the marsupial Monodelphis domestica.

    OpenAIRE

    Sasagawa, I; Ferguson, M W

    1991-01-01

    In Monodelphis domestica, although both processes from odontoblasts and projections from ameloblasts were found in developing enamel, the majority of the contents of enamel tubules were probably processes that originated from odontoblasts. Processes from odontoblasts penetrating into enamel touched part of the ameloblasts in the stage of enamel formation. No specialised cell junctions were seen at the adherence between the two. There were no enamel tubules in the aprismatic and pseudoprismati...

  1. Low-dose radiation as an environmental agent affecting intrauterine development

    International Nuclear Information System (INIS)

    Kameyama, Yoshiro

    1982-01-01

    The low-dose radiation effects which have been recognized in mammalian teratological studies are direct injuries to the particularly radiosensitive tissues of embryo and fetus, and increased incidences of spontaneous malformations and minor anomalies. The lowest radiation doses for manifestation of those effects in mice and rats are: 5 rad for resorption of preimplantation embryos; 5-10 rad for acute cytological changes such as pyknosis, cytoplasmic degeneration and mitotic delay; 5 rad for increasing frequency of spontaneous minor anomalies of the skeleton; 15-20 rad for malformations of the eye, brain and spinal cord; 20-25 rad for histogenetic and functional disorders of the central nervous system; and 20-25 rad for impaired fertility. Pregnant women who are subject to X-ray examination are much concerned about potential hazard of radiation to their offspring in utero. The above experimental findings suggest that the possibility of teratogenic effects of diagnostic radiation on human embryos and fetuses is extremely low, and probably negligible, given the proper dose control measures. (author)

  2. Does the amount of tagged stool and fluid significantly affect the radiation exposure in low-dose CT colonography performed with an automatic exposure control?

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Hyun Kyong; Lee, Kyoung Ho; Kim, So Yeon; Kim, Young Hoon [Seoul National University Bundang Hospital, Department of Radiology, Seongnam-si, Gyeonggi-do (Korea, Republic of); Seoul National University College of Medicine, Seoul National University Medical Research Center, Institute of Radiation Medicine, Bundang (Korea, Republic of); Kim, Kil Joong [Seoul National University College of Medicine, Department of Radiation Applied Life Science, Seoul (Korea, Republic of); Kim, Bohyoung; Lee, Hyunna [Seoul National University, School of Computer Science and Engineering, Seoul (Korea, Republic of); Park, Seong Ho [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Seoul (Korea, Republic of); Yanof, Jeffrey H. [Philips Healthcare, CT Clinical Science, Cleveland, OH (United States); Hwang, Seung-sik [Inha University School of Medicine, Department of Social and Preventive Medicine, Incheon (Korea, Republic of)

    2011-02-15

    To determine whether the amount of tagged stool and fluid significantly affects the radiation exposure in low-dose screening CT colonography performed with an automatic tube-current modulation technique. The study included 311 patients. The tagging agent was barium (n = 271) or iodine (n = 40). Correlation was measured between mean volume CT dose index (CTDI{sub vol}) and the estimated x-ray attenuation of the tagged stool and fluid (ATT). Multiple linear regression analyses were performed to determine the effect of ATT on CTDI{sub vol} and the effect of ATT on image noise while adjusting for other variables including abdominal circumference. CTDI{sub vol} varied from 0.88 to 2.54 mGy. There was no significant correlation between CTDI{sub vol} and ATT (p = 0.61). ATT did not significantly affect CTDI{sub vol} (p = 0.93), while abdominal circumference was the only factor significantly affecting CTDI{sub vol} (p < 0.001). Image noise ranged from 59.5 to 64.1 HU. The p value for the regression model explaining the noise was 0.38. The amount of stool and fluid tagging does not significantly affect radiation exposure. (orig.)

  3. Does the amount of tagged stool and fluid significantly affect the radiation exposure in low-dose CT colonography performed with an automatic exposure control?

    International Nuclear Information System (INIS)

    Lim, Hyun Kyong; Lee, Kyoung Ho; Kim, So Yeon; Kim, Young Hoon; Kim, Kil Joong; Kim, Bohyoung; Lee, Hyunna; Park, Seong Ho; Yanof, Jeffrey H.; Hwang, Seung-sik

    2011-01-01

    To determine whether the amount of tagged stool and fluid significantly affects the radiation exposure in low-dose screening CT colonography performed with an automatic tube-current modulation technique. The study included 311 patients. The tagging agent was barium (n = 271) or iodine (n = 40). Correlation was measured between mean volume CT dose index (CTDI vol ) and the estimated x-ray attenuation of the tagged stool and fluid (ATT). Multiple linear regression analyses were performed to determine the effect of ATT on CTDI vol and the effect of ATT on image noise while adjusting for other variables including abdominal circumference. CTDI vol varied from 0.88 to 2.54 mGy. There was no significant correlation between CTDI vol and ATT (p = 0.61). ATT did not significantly affect CTDI vol (p = 0.93), while abdominal circumference was the only factor significantly affecting CTDI vol (p < 0.001). Image noise ranged from 59.5 to 64.1 HU. The p value for the regression model explaining the noise was 0.38. The amount of stool and fluid tagging does not significantly affect radiation exposure. (orig.)

  4. A Low Ethanol Dose Affects all Types of Cells in Mixed Long-Term Embryonic Cultures of the Cerebellum

    DEFF Research Database (Denmark)

    Pickering, Chris; Wicher, Grzegorz; Rosendahl, Sofi

    2010-01-01

    of this ethanol dose, cultures were exposed for 30 days. After this period, virtually no neurons or myelinating oligodendrocytes were present in the ethanol-treated cultures. In conclusion, chronic exposure to ethanol, even at small doses, dramatically and persistently affects normal development........ We exposed a primary culture of rat cerebellum from embryonic day 17 (corresponding to second trimester in humans) to ethanol at a concentration of 17.6 mM which is roughly equivalent to one glass of wine. Acutely, there was no change in cell viability after 5 or 8 days of exposure relative...... to control. By 11 days, a reduction in the number of viable cells was observed without an accompanying change in caspase-3 activity (marker of apoptotic cell death), suggesting changes in cell proliferation. As the proportion of nestin-positive cells was higher in the ethanol-treated cultures after 5 days...

  5. Low Dose Gamma Irradiation Does Not Affect the Quality or Total Ascorbic Acid Concentration of "Sweetheart" Passionfruit (Passiflora edulis).

    Science.gov (United States)

    Golding, John B; Blades, Barbara L; Satyan, Shashirekha; Spohr, Lorraine J; Harris, Anne; Jessup, Andrew J; Archer, John R; Davies, Justin B; Banos, Connie

    2015-08-26

    Passionfruit ( Passiflora edulis , Sims, cultivar "Sweetheart") were subject to gamma irradiation at levels suitable for phytosanitary purposes (0, 150, 400 and 1000 Gy) then stored at 8 °C and assessed for fruit quality and total ascorbic acid concentration after one and fourteen days. Irradiation at any dose (≤1000 Gy) did not affect passionfruit quality (overall fruit quality, colour, firmness, fruit shrivel, stem condition, weight loss, total soluble solids level (TSS), titratable acidity (TA) level, TSS/TA ratio, juice pH and rot development), nor the total ascorbic acid concentration. The length of time in storage affected some fruit quality parameters and total ascorbic acid concentration, with longer storage periods resulting in lower quality fruit and lower total ascorbic acid concentration, irrespective of irradiation. There was no interaction between irradiation treatment and storage time, indicating that irradiation did not influence the effect of storage on passionfruit quality. The results showed that the application of 150, 400 and 1000 Gy gamma irradiation to "Sweetheart" purple passionfruit did not produce any deleterious effects on fruit quality or total ascorbic acid concentration during cold storage, thus supporting the use of low dose irradiation as a phytosanitary treatment against quarantine pests in purple passionfruit.

  6. Doses and affects of radon and its daughters

    International Nuclear Information System (INIS)

    Snihs, J.O.

    1982-01-01

    Radon and its short-lived daughters are one of the main contributors to the natural exposures of ionizing radiation to man. Their sources, levels and characteristics are described. By inhalation of radon and its daughters tissues in the lung are irritated by α-particles leading to an increased risk of lung cancer. Methods of calculation of doses and risks using the dosimetric approach and the epidemiological approach are described and discussed. (Author)

  7. Radiological dose reconstruction for birds reconciles outcomes of Fukushima with knowledge of dose-effect relationships

    International Nuclear Information System (INIS)

    Garnier-Laplace, Jacqueline; Beaugelin-Seiller, Karine; Della-Vedova, Claire; Metivier, Jean-Michel; Ritz, Christian; Mousseau, Timothy A.; Pape Moeller, Anders

    2015-01-01

    We reconstructed the radiological dose for birds observed at 300 census sites in the 50-km northwest area affected by the accident at the Fukushima Daiichi nuclear power plant over 2011-2014. Substituting the ambient dose rate measured at the census points (from 0.16 to 31 μGy h -1 ) with the dose rate reconstructed for adult birds of each species (from 0.3 to 97 μGy h -1 ), we confirmed that the overall bird abundance at Fukushima decreased with increasing total doses. This relationship was directly consistent with exposure levels found in the literature to induce physiological disturbances in birds. Among the 57 species constituting the observed bird community, we found that 90% were likely chronically exposed at a dose rate that could potentially affect their reproductive success. We quantified a loss of 22.6% of the total number of individuals per increment of one unit log10-transformed total dose (in Gy), over the four-year post-accident period in the explored area. We estimated that a total dose of 0.55 Gy reduced by 50% the total number of birds in the study area over 2011-2014. The data also suggest a significant positive relationship between total dose and species diversity. (authors)

  8. An endocrine disruptor, bisphenol A, affects development in the protochordate Ciona intestinalis: Hatching rates and swimming behavior alter in a dose-dependent manner

    International Nuclear Information System (INIS)

    Matsushima, Ayami; Ryan, Kerrianne; Shimohigashi, Yasuyuki; Meinertzhagen, Ian A.

    2013-01-01

    Bisphenol A (BPA) is widely used industrially to produce polycarbonate plastics and epoxy resins. Numerous studies document the harmful effects caused by low-dose BPA exposure especially on nervous systems and behavior in experimental animals such as mice and rats. Here, we exposed embryos of a model chordate, Ciona intestinalis, to seawater containing BPA to evaluate adverse effects on embryonic development and on the swimming behavior of subsequent larvae. Ciona is ideal because its larva develops rapidly and has few cells. The rate of larval hatching decreased in a dose-dependent manner with exposures to BPA above 3 μM; swimming behavior was also affected in larvae emerging from embryos exposed to 1 μM BPA. Adverse effects were most severe on fertilized eggs exposed to BPA within 7 h post-fertilization. Ciona shares twelve nuclear receptors with mammals, and BPA is proposed to disturb the physiological functions of one or more of these. - Highlights: ► Embryos of Ciona intestinalis were exposed to BPA to evaluate its developmental effects. ► The rate of larval hatching decreased in a dose-dependent manner. ► Swimming behavior was affected in larvae that emerge from embryos exposed to 1 μM BPA. ► Our findings will support a new strategy to analyze the developmental effects induced by BPA. - Exposure of fertilized Ciona embryos to BPA decreased their hatch rate in a dose-dependent manner and led to abnormal larval swimming behavior.

  9. Dentin and pulp sense cold stimulus.

    Science.gov (United States)

    Tokuda, Masayuki; Tatsuyama, Shoko; Fujisawa, Mari; Morimoto-Yamashita, Yoko; Kawakami, Yoshiko; Shibukawa, Yoshiyuki; Torii, Mistuso

    2015-05-01

    Dentin hypersensitivity is a common symptom, and recent convergent evidences have reported transient receptor potential (TRP) channels in odontoblasts act as mechanical and thermal molecular sensor, which detect stimulation applied on the exposed dentin surface, to drive multiple odontoblastic cellular functions, such as sensory transduction and/or dentin formation. In the present study, we confirmed expression of TRP melastatin subfamily member-8 (TRPM8) channels in primary cultured cells derived from human dental pulp cells (HPCs) and mouse odontoblast-lineage cells (OLCs) as well as in dentin matrix protein-1 (DMP-1) and dentin sialoprotein (DSP) positive acutely isolated rat odontoblasts from dental pulp tissue slice culture by immunohistochemical analyses. In addition, we detected TRPM8 channel expression on HPCs and OLCs by RT-PCR and Western blotting analyses. These results indicated that both odontoblasts and dental pulp cells express TRPM8 channels in rat, mouse and human, and therefore we hypothesize they may contribute as cold sensor in tooth. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Factors affecting radiation doses from dedicated rail transport of spent reactor fuel

    International Nuclear Information System (INIS)

    Martin, J.E.

    1988-01-01

    This paper reports there are two exposure control concerns associated with the shipment of spent reactor fuel in dedicated trains -- compliance with transportation regulations for maximum allowable radiation levels, and minimizing the dose received by the general public. This article examines the methods used to calculate the dose equivalent rates alongside stationary (transport regulations) and moving trains (public exposure) of various lengths. The factors examined include the source term, the effect of overlapping radiation fields, the speed of the train, and the location of the population relative to the train. Trains made up of series of cars that individually meet transport regulations can, as a whole, exceed transport vehicle dose equivalent rate limits by up to 23% due to overlapping radiation fields. For moving trains and the worst case analyzed -- a person located 20 feet from the tracks and a train speed of 5 mph --- 141 rail cars would have to pass by to deliver a dose equivalent of 1 mrem

  11. Fipronil promotes motor and behavioral changes in honey bees (Apis mellifera) and affects the development of colonies exposed to sublethal doses.

    Science.gov (United States)

    Zaluski, Rodrigo; Kadri, Samir Moura; Alonso, Diego Peres; Martins Ribolla, Paulo Eduardo; de Oliveira Orsi, Ricardo

    2015-05-01

    Bees play a crucial role in pollination and generate honey and other hive products; therefore, their worldwide decline is cause for concern. New broad-spectrum systemic insecticides such as fipronil can harm bees and their use has been discussed as a potential threat to bees' survival. In the present study, the authors evaluate the in vitro toxicity of fipronil and note behavioral and motor activity changes in Africanized adult Apis mellifera that ingest or come into contact with lethal or sublethal doses of fipronil. The effects of sublethal doses on brood viability, population growth, behavior, and the expression of the defensin 1 gene in adult bees were studied in colonies fed with contaminated sugar syrup (8 µg fipronil L(-1) ). Fipronil is highly toxic to bees triggering agitation, seizures, tremors, and paralysis. Bees that are exposed to a lethal or sublethal doses showed reduced motor activity. The number of eggs that hatched, the area occupied by worker eggs, and the number of larvae and pupae that developed were reduced, adult bees showed lethargy, and colonies were abandoned when they were exposed to sublethal doses of fipronil. No change was seen in the bees' expression of defensin 1. The authors conclude that fipronil is highly toxic to honey bees and even sublethal doses may negatively affect the development and maintenance of colonies. © 2015 SETAC.

  12. Bodily activity measurements and estimation of dose by inner contamination during 1993-1994 in children from areas affected by the Chernobyl accident

    International Nuclear Information System (INIS)

    Arado Lopez, Orquidea; Lopez Bejerano, Gladys; Cornejo Diaz, Nestor; Cruz Suarez, Rodolfo; Valdes Ramos, Maryzury

    1996-01-01

    At the whole body counter laboratory installed at the Jose Marti Pioneers City, measurements to determine inner contamination with Cesium 137 were taken of 463 Ukrainian children from areas affected by The Chernobyl accident. Starting from the measured activity, both the incorporated activity and the inner dose were estimated according to the ICRP latest recommendations, which take age into account. The results obtained showed that a 46,9 % of the measured children presented a bodily activity of cesium 137 higher to the minimal detectable activity. The highest valve that was calculated for the effective dose in this group of children was 9,2 mSv

  13. Outdoor γ-ray dose rate in Ajigasawa Town and environmental factors affecting it in IES

    International Nuclear Information System (INIS)

    Iyogi, Takashi; Hisamatsu, Shunichi; Sakurai, Naoyuki; Koyama, Kenji

    1999-01-01

    We surveyed the outdoor γ-ray dose rate throughout Aomori Prefecture from 1991 to 1995, and found an annual mean dose rate of 46 nGy h -1 . Relatively high dose rates were also observed in several areas (municipalities) of the survey locations. In this study, we examined the detailed distribution of the γ-ray dose rate in one such high dose rate area, Ajigasawa Town. Glass dosimeters were used for the monitoring of cumulative γ-ray dose rate at 10 locations in the town. The dose rate from each radioactive nuclide in the ground at the monitoring locations was measured by using an in situ γ-ray spectrometer with a Ge detector. The results obtained with the glass dosimeters showed that the γ-ray dose rates in Ajigasawa Town varied from 48 to 57 nGy h -1 . Although the dose rates were generally higher than the mean dose in Aomori Prefecture (1992-1995), the rates were lower than other high dose rate areas which had already been measured. The in situ γ-ray spectrometry revealed that these relatively high dose rates were mainly caused by 40 K and Th series radionuclides in the town. The effect of meteorological conditions on the γ-ray dose rate was studied at a monitoring station in IES. The dose rate was continuously recorded by a DBM NaI(Tl) scintillation detector system. The mean dose rate obtained when precipitation was sensed was 27 nGy h -1 and higher than when no precipitation was sensed (23 nGy h -1 ). (author)

  14. Inhaled corticosteroid metered-dose inhalers: how do variations in technique for solutions versus suspensions affect drug distribution?

    Science.gov (United States)

    Robinson, Christie A; Tsourounis, Candy

    2013-03-01

    To assess the literature that evaluates how variations in metered-dose inhaler (MDI) technique affect lung distribution for inhaled corticosteroids (ICSs) formulated as MDI suspensions and solutions. PubMed (up to November 2012) and Cochrane Library (up to November 2012) were searched using the terms metered-dose inhalers, HFA 134a, Asthma/*drug therapy, and inhaled corticosteroids. In addition, reference citations from publications identified were reviewed. All articles in English from the data sources that assessed MDI technique comparing total lung distribution (TLD) of MDI solutions or suspensions formulated with ICSs were included in the review. Five relevant studies were identified. Five controlled studies compared how variations in MDI technique affect TLD for ICS MDI solutions with suspensions. MDI solutions resulted in greater TLD compared with larger particle MDI suspensions. Delayed or early inspiration upon device actuation of MDI solutions resulted in less TLD than coordinated actuation, but with a 3- to 4-times greater TLD than MDI suspensions inhaled using a standard technique. A sixth study evaluated inspiratory flow rates (IFR) for small, medium, and large particles. Rapid and slow IFRs resulted in similar TLD for small particles, while far fewer particles reached the airways with medium and large particles at rapid, rather than slow, IFRs. Based on the literature evaluated, standard MDI technique should be used for ICS suspensions. ICS MDI solutions can provide a higher average TLD than larger-particle ICS suspensions using standard technique, discoordinated inspiration and medication actuation timing, or rapid and slow IFRs. ICS MDI solutions allow for a more forgiving technique, which makes them uniquely suitable options for patients with asthma who have difficultly with MDI technique.

  15. Notes on the effect of dose uncertainty

    International Nuclear Information System (INIS)

    Morris, M.D.

    1987-01-01

    The apparent dose-response relationship between amount of exposure to acute radiation and level of mortality in humans is affected by uncertainties in the dose values. It is apparent that one of the greatest concerns regarding the human data from Hiroshima and Nagasaki is the unexpectedly shallow slope of the dose response curve. This may be partially explained by uncertainty in the dose estimates. Some potential effects of dose uncertainty on the apparent dose-response relationship are demonstrated

  16. Dose rate effect on low-dose hyper-radiosensitivity with cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Geon-Min; Kim, Eun-Hee [Seoul National University, Seoul (Korea, Republic of)

    2016-10-15

    Low-dose hyper-radiosensitivity (HRS) is the phenomenon that mammalian cells exhibit higher sensitivity to radiation at low doses (< 0.5 Gy) than expected by the linear-quadratic model. At doses above 0.5Gy, the cellular response is recovered to the level expected by the linear-quadratic model. This transition is called the increased radio-resistance (IRR). HRS was first verified using Chinese hamster V79 cells in vitro by Marples and has been confirmed in studies with other cell lines including human normal and tumor cells. HRS is known to be induced by inactivation of ataxia telangiectasia-mutated (ATM), which plays a key role in repairing DNA damages. Considering the connection between ATM and HRS, one can infer that dose rate may affect cellular response regarding HRS at low doses. In this study, we quantitated the effect of dose rate on HRS by clonogenic assay with normal and tumor cells. The HRS of cells at low dose exposures is a phenomenon already known. In this study, we observed HRS of rat normal diencephalon cells and rat gliosarcoma cells at doses below 1 Gy. In addition, we found that dose rate mattered. HRS occurred at low doses, but only when total dose was delivered at a rate below certain level.

  17. Performance of commercial platforms for rapid genotyping of polymorphisms affecting warfarin dose.

    Science.gov (United States)

    King, Cristi R; Porche-Sorbet, Rhonda M; Gage, Brian F; Ridker, Paul M; Renaud, Yannick; Phillips, Michael S; Eby, Charles

    2008-06-01

    Initiation of warfarin therapy is associated with bleeding owing to its narrow therapeutic window and unpredictable therapeutic dose. Pharmacogenetic-based dosing algorithms can improve accuracy of initial warfarin dosing but require rapid genotyping for cytochrome P-450 2C9 (CYP2C9) *2 and *3 single nucleotide polymorphisms (SNPs) and a vitamin K epoxide reductase (VKORC1) SNP. We evaluated 4 commercial systems: INFINITI analyzer (AutoGenomics, Carlsbad, CA), Invader assay (Third Wave Technologies, Madison, WI), Tag-It Mutation Detection assay (Luminex Molecular Diagnostics, formerly Tm Bioscience, Toronto, Canada), and Pyrosequencing (Biotage, Uppsala, Sweden). We genotyped 112 DNA samples and resolved any discrepancies with bidirectional sequencing. The INFINITI analyzer was 100% accurate for all SNPs and required 8 hours. Invader and Tag-It were 100% accurate for CYP2C9 SNPs, 99% accurate for VKORC1 -1639/3673 SNP, and required 3 hours and 8 hours, respectively. Pyrosequencing was 99% accurate for CYP2C9 *2, 100% accurate for CYP2C9 *3, and 100% accurate for VKORC1 and required 4 hours. Current commercial platforms provide accurate and rapid genotypes for pharmacogenetic dosing during initiation of warfarin therapy.

  18. The frequency of chromatide aberrations as a function of radiation dose estimated by the number of dicentrics found by the cytogenetic analysis of lymphocytes in subjects affected by the Chernobyl accident

    International Nuclear Information System (INIS)

    Nugis, V.Yu.; Chirkov, A.A.

    1990-01-01

    A study was made of the frequency of chromatide aberrations in lymphocyte culture of subjects affected by the Chernobyl accident as a function of dose estimated by the incidence of dicentrics. The average number of chromatide aberrations was nearly the same within the dose range from 0 to 5 Gy exhibiting a tendency towards growth with dose. A high individual variability of the chromatide aberration frequency was observed

  19. Radiological dose reconstruction for birds reconciles outcomes of Fukushima with knowledge of dose-effect relationships

    DEFF Research Database (Denmark)

    Garnier-Laplace, Jacqueline; Beaugelin-Seiller, Karine; Della-Vedova, Claire

    2015-01-01

    We reconstructed the radiological dose for birds observed at 300 census sites in the 50-km northwest area affected by the accident at the Fukushima Daiichi nuclear power plant over 2011-2014. Substituting the ambient dose rate measured at the census points (from 0.16 to 31 μGy h(-1)) with the dos...

  20. Downregulation of adenomatous polyposis coli by microRNA-663 promotes odontogenic differentiation through activation of Wnt/beta-catenin signaling

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae-Sung; Park, Min-Gyeong; Lee, Seul Ah; Park, Sun-Young; Kim, Heung-Joong; Yu, Sun-Kyoung; Kim, Chun Sung; Kim, Su-Gwan; Oh, Ji-Su; You, Jae-Seek; Kim, Jin-Soo; Seo, Yo-Seob [Oral Biology Research Institute, School of Dentistry, Chosun University, Gwangju 501-759 (Korea, Republic of); Chun, Hong Sung [Department of Biomedical Science, Chosun University, Gwangju 501-759 (Korea, Republic of); Park, Joo-Cheol [Department of Oral Histology-Developmental Biology, School of Dentistry and Dental Research Institute, BK 21, Seoul National University, Seoul 110-749 (Korea, Republic of); Kim, Do Kyung, E-mail: kdk@chosun.ac.kr [Oral Biology Research Institute, School of Dentistry, Chosun University, Gwangju 501-759 (Korea, Republic of)

    2014-04-18

    Highlights: • miR-663 is significantly up-regulated during MDPC-23 odontoblastic cell differentiation. • miR-663 accelerates mineralization in MDPC-23 odontoblastic cells without cell proliferation. • miR-663 promotes odontoblastic cell differentiation by targeting APC and activating Wnt/β-catenin signaling in MDPC-23 cells. - Abstract: MicroRNAs (miRNAs) regulate cell differentiation by inhibiting mRNA translation or by inducing its degradation. However, the role of miRNAs in odontogenic differentiation is largely unknown. In this present study, we observed that the expression of miR-663 increased significantly during differentiation of MDPC-23 cells to odontoblasts. Furthermore, up-regulation of miR-663 expression promoted odontogenic differentiation and accelerated mineralization without proliferation in MDPC-23 cells. In addition, target gene prediction for miR-663 revealed that the mRNA of the adenomatous polyposis coli (APC) gene, which is associated with the Wnt/β-catenin signaling pathway, has a miR-663 binding site in its 3′-untranslated region (3′UTR). Furthermore, APC expressional was suppressed significantly by miR-663, and this down-regulation of APC expression triggered activation of Wnt/β-catenin signaling through accumulation of β-catenin in the nucleus. Taken together, these findings suggest that miR-663 promotes differentiation of MDPC-23 cells to odontoblasts by targeting APC-mediated activation of Wnt/β-catenin signaling. Therefore, miR-663 can be considered a critical regulator of odontoblast differentiation and can be utilized for developing miRNA-based therapeutic agents.

  1. Vancomycin Dosing in Obese Patients: Special Considerations and Novel Dosing Strategies.

    Science.gov (United States)

    Durand, Cheryl; Bylo, Mary; Howard, Brian; Belliveau, Paul

    2018-06-01

    To review the literature regarding vancomycin pharmacokinetics in obese patients and strategies used to improve dosing in this population. PubMed, EMBASE (1974 to November 2017), and Google Scholar searches were conducted using the search terms vancomycin, obese, obesity, pharmacokinetics, strategy, and dosing. Additional articles were selected from reference lists of selected studies. Included articles were those published in English with a primary focus on vancomycin pharmacokinetic parameters in obese patients and practical vancomycin dosing strategies, clinical experiences, or challenges of dosing vancomycin in this population. Volume of distribution and clearance are the pharmacokinetic parameters that most often affect vancomycin dosing in obese patients; both are increased in this population. Challenges with dosing in obese patients include inconsistent and inadequate dosing, observations that the obese population may not be homogeneous, and reports of an increased likelihood of supratherapeutic trough concentrations. Investigators have revised and developed dosing and monitoring protocols to address these challenges. These approaches improved target trough attainment to varying degrees. Some of the vancomycin dosing approaches provided promising results in obese patients, but there were notable differences in methods used to develop these approaches, and sample sizes were small. Although some approaches can be considered for validation in individual institutions, further research is warranted. This may include validating approaches in larger populations with narrower obesity severity ranges, investigating target attainment in indication-specific target ranges, and evaluating the impact of different dosing weights and methods of creatinine clearance calculation.

  2. Caffeine at a Moderate Dose Did Not Affect the Skeletal System of Rats with Streptozotocin-Induced Diabetes

    Directory of Open Access Journals (Sweden)

    Joanna Folwarczna

    2017-10-01

    Full Text Available Diabetes may lead to the development of osteoporosis. Coffee drinking, apart from its health benefits, is taken into consideration as an osteoporosis risk factor. Data from human and animal studies on coffee and caffeine bone effects are inconsistent. The aim of the study was to investigate effects of caffeine at a moderate dose on the skeletal system of rats in two models of experimental diabetes induced by streptozotocin. Effects of caffeine administered orally (20 mg/kg aily for four weeks were investigated in three-month-old female Wistar rats, which, two weeks before the start of caffeine administration, received streptozotocin (60 mg/kg, intraperitoneally alone or streptozotocin after nicotinamide (230 mg/kg, intraperitoneally. Bone turnover markers, mass, mineral density, histomorphometric parameters, and mechanical properties were examined. Streptozotocin induced diabetes, with profound changes in the skeletal system due to increased bone resorption and decreased bone formation. Although streptozotocin administered after nicotinamide induced slight increases in glucose levels at the beginning of the experiment only, slight, but significant unfavorable changes in the skeletal system were demonstrated. Administration of caffeine did not affect the investigated skeletal parameters of rats with streptozotocin-induced disorders. In conclusion, caffeine at a moderate dose did not exert a damaging effect on the skeletal system of diabetic rats.

  3. Caffeine at a Moderate Dose Did Not Affect the Skeletal System of Rats with Streptozotocin-Induced Diabetes.

    Science.gov (United States)

    Folwarczna, Joanna; Janas, Aleksandra; Cegieła, Urszula; Pytlik, Maria; Śliwiński, Leszek; Matejczyk, Magdalena; Nowacka, Anna; Rudy, Karolina; Krivošíková, Zora; Štefíková, Kornélia; Gajdoš, Martin

    2017-10-30

    Diabetes may lead to the development of osteoporosis. Coffee drinking, apart from its health benefits, is taken into consideration as an osteoporosis risk factor. Data from human and animal studies on coffee and caffeine bone effects are inconsistent. The aim of the study was to investigate effects of caffeine at a moderate dose on the skeletal system of rats in two models of experimental diabetes induced by streptozotocin. Effects of caffeine administered orally (20 mg/kg aily for four weeks) were investigated in three-month-old female Wistar rats, which, two weeks before the start of caffeine administration, received streptozotocin (60 mg/kg, intraperitoneally) alone or streptozotocin after nicotinamide (230 mg/kg, intraperitoneally). Bone turnover markers, mass, mineral density, histomorphometric parameters, and mechanical properties were examined. Streptozotocin induced diabetes, with profound changes in the skeletal system due to increased bone resorption and decreased bone formation. Although streptozotocin administered after nicotinamide induced slight increases in glucose levels at the beginning of the experiment only, slight, but significant unfavorable changes in the skeletal system were demonstrated. Administration of caffeine did not affect the investigated skeletal parameters of rats with streptozotocin-induced disorders. In conclusion, caffeine at a moderate dose did not exert a damaging effect on the skeletal system of diabetic rats.

  4. Immunohistochemical Examination for the Distribution of Podoplanin-Expressing Cells in Developing Mouse Molar Tooth Germs

    Science.gov (United States)

    Imaizumi, Yuri; Amano, Ikuko; Tsuruga, Eichi; Kojima, Hiroshi; Sawa, Yoshihiko

    2010-01-01

    We recently reported the expression of podoplanin in the apical bud of adult mouse incisal tooth. This study was aimed to investigate the distribution of podoplanin-expressing cells in mouse tooth germs at several developing stages. At the bud stage podoplanin was expressed in oral mucous epithelia and in a tooth bud. At the cap stage podoplanin was expressed on inner and outer enamel epithelia but not in mesenchymal cells expressing the neural crest stem cell marker nestin. At the early bell stage nestin and podoplanin were expressed in cervical loop and odontoblasts. At the root formation stage both nestin and podoplanin were weakly expressed in odontoblasts generating radicular dentin. Podoplanin expression was also found in the Hertwig epithelial sheath. These results suggest that epithelial cells of developing tooth germ acquire the ability to express nestin, and that tooth germ epithelial cells maintain the ability to express podoplanin in oral mucous epithelia. The expression of podoplanin in odontoblasts was induced as tooth germ development advanced, but was suppressed with the completion of the primary dentin, suggesting that podoplanin may be involved in the cell growth of odontoblasts. Nestin may function as an intermediate filament that binds podoplanin in odontoblasts. PMID:21060740

  5. The autoradiographic pattern of the in vitro uptake of proline by the coronal areas of intact and carious human teeth

    International Nuclear Information System (INIS)

    Karjalainen, S.; Soederling, E.

    1979-01-01

    The biosynthesis of collagen in teeth was studied by following the uptake of proline in vitro. Whole crowns of human teeth were incubated for 6 h with ( 14 C)- or ( 3 H)-proline. Autoradiographs were prepared from sections of intact teeth and teeth with carious lesions of varying depths and location. The number of silver grains per cm 2 in the predentine, odontoblast layer and pulp were counted in selected fields magnified x 430 representing the deepest parts of the carious lesions. No differences in the labelling pattern were observed between the intact teeth incubated freshly after extraction and those preserved in liquid nitrogen. The densest labelling of intact teeth was seen in the predentine and odontoblast layer. The alterations under initial dentine caries appeared as increased labelling of the predentine and decreased labelling of the odontoblast layer; no alterations were observed in the underlying pulp. In advanced lesions, the predentine labelling decreased and that in the odontoblast layer and pulp increased. In the initial stages, caries seem to activate collagen synthesis in a relatively restricted area of the underlying structures, but in advanced stages, caries seem to increase the odontoblastic cellular polypeptide chain formation but prevent further maturation of the collagen. (author)

  6. Autoradiographic pattern of the in vitro uptake of proline by the coronal areas of intact and carious human teeth

    Energy Technology Data Exchange (ETDEWEB)

    Karjalainen, S; Soederling, E [Turku Univ. (Finland)

    1979-01-01

    The biosynthesis of collagen in teeth was studied by following the uptake of proline in vitro. Whole crowns of human teeth were incubated for 6 h with (/sup 14/C)- or (/sup 3/H)-proline. Autoradiographs were prepared from sections of intact teeth and teeth with carious lesions of varying depths and location. The number of silver grains per cm/sup 2/ in the predentine, odontoblast layer and pulp were counted in selected fields magnified x 430 representing the deepest parts of the carious lesions. No differences in the labelling pattern were observed between the intact teeth incubated freshly after extraction and those preserved in liquid nitrogen. The densest labelling of intact teeth was seen in the predentine and odontoblast layer. The alterations under initial dentine caries appeared as increased labelling of the predentine and decreased labelling of the odontoblast layer; no alterations were observed in the underlying pulp. In advanced lesions, the predentine labelling decreased and that in the odontoblast layer and pulp increased. In the initial stages, caries seem to activate collagen synthesis in a relatively restricted area of the underlying structures, but in advanced stages, caries seem to increase the odontoblastic cellular polypeptide chain formation but prevent further maturation of the collagen.

  7. Analysis of Cumulative Dose to Implanted Pacemaker According to Various IMRT Delivery Methods: Optimal Dose Delivery Versus Dose Reduction Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Woo; Hong, Se Mie [Dept. of Radiation Oncology, Konkuk University Medical Center, Seoul (Korea, Republic of)

    2011-11-15

    Cancer patients with implanted cardiac pacemaker occasionally require radiotherapy. Pacemaker may be damaged or malfunction during radiotherapy due to ionizing radiation or electromagnetic interference. Although radiotherapy should be planned to keep the dose to pacemaker as low as possible not to malfunction ideally, current radiation treatment planning (RTP) system does not accurately calculate deposited dose to adjacent field border or area beyond irradiated fields. In terms of beam delivery techniques using multiple intensity modulated fields, dosimetric effect of scattered radiation in high energy photon beams is required to be detailed analyzed based on measurement data. The aim of this study is to evaluate dose discrepancies of pacemaker in a RTP system as compared to measured doses. We also designed dose reduction strategy limited value of 2 Gy for radiation treatment patients with cardiac implanted pacemaker. Total accumulated dose of 145 cGy based on in-vivo dosimetry was satisfied with the recommendation criteria to prevent malfunction of pacemaker in SS technique. However, the 2 mm lead shielder enabled the scattered doses to reduce up to 60% and 40% in the patient and the phantom, respectively. The SS technique with the lead shielding could reduce the accumulated scattered doses less than 100 cGy. Calculated and measured doses were not greatly affected by the beam delivery techniques. In-vivo and measured doses on pacemaker position showed critical dose discrepancies reaching up to 4 times as compared to planned doses in RTP. The current SS technique could deliver lower scattered doses than recommendation criteria, but use of 2 mm lead shielder contributed to reduce scattered doses by 60%. The tertiary lead shielder can be useful to prevent malfunction or electrical damage of implanted pacemakers during radiotherapy. It is required to estimate more accurate scattered doses of the patient or medical device in RTP to design proper dose reduction strategy.

  8. Analysis of Cumulative Dose to Implanted Pacemaker According to Various IMRT Delivery Methods: Optimal Dose Delivery Versus Dose Reduction Strategy

    International Nuclear Information System (INIS)

    Lee, Jeong Woo; Hong, Se Mie

    2011-01-01

    Cancer patients with implanted cardiac pacemaker occasionally require radiotherapy. Pacemaker may be damaged or malfunction during radiotherapy due to ionizing radiation or electromagnetic interference. Although radiotherapy should be planned to keep the dose to pacemaker as low as possible not to malfunction ideally, current radiation treatment planning (RTP) system does not accurately calculate deposited dose to adjacent field border or area beyond irradiated fields. In terms of beam delivery techniques using multiple intensity modulated fields, dosimetric effect of scattered radiation in high energy photon beams is required to be detailed analyzed based on measurement data. The aim of this study is to evaluate dose discrepancies of pacemaker in a RTP system as compared to measured doses. We also designed dose reduction strategy limited value of 2 Gy for radiation treatment patients with cardiac implanted pacemaker. Total accumulated dose of 145 cGy based on in-vivo dosimetry was satisfied with the recommendation criteria to prevent malfunction of pacemaker in SS technique. However, the 2 mm lead shielder enabled the scattered doses to reduce up to 60% and 40% in the patient and the phantom, respectively. The SS technique with the lead shielding could reduce the accumulated scattered doses less than 100 cGy. Calculated and measured doses were not greatly affected by the beam delivery techniques. In-vivo and measured doses on pacemaker position showed critical dose discrepancies reaching up to 4 times as compared to planned doses in RTP. The current SS technique could deliver lower scattered doses than recommendation criteria, but use of 2 mm lead shielder contributed to reduce scattered doses by 60%. The tertiary lead shielder can be useful to prevent malfunction or electrical damage of implanted pacemakers during radiotherapy. It is required to estimate more accurate scattered doses of the patient or medical device in RTP to design proper dose reduction strategy.

  9. Factors affecting calculations of dose resulting from a tritium release into the atmosphere

    International Nuclear Information System (INIS)

    Otaduy, P.; Easterly, C.E.; Booth, R.S.; Jacobs, D.G.

    1976-01-01

    Tritium releases in the form of HT represent a lower hazard to man than releases as HTO. However, during movement in the environment, HT is converted into HTO. The effects of the conversion rate on calcultions of dose are described, and a general method is presented for determining the dose from tritium for various conversion rates and relative HTO/HT risk factors

  10. Health effect of low dose/low dose rate radiation

    International Nuclear Information System (INIS)

    Kodama, Seiji

    2012-01-01

    The clarified and non-clarified scientific knowledge is discussed to consider the cause of confusion of explanation of the title subject. The low dose is defined roughly lower than 200 mGy and low dose rate, 0.05 mGy/min. The health effect is evaluated from 2 aspects of clinical symptom/radiation hazard protection. In the clinical aspect, the effect is classified in physical (early and late) and genetic ones, and is classified in stochastic (no threshold value, TV) and deterministic (with TV) ones from the radioprotection aspect. Although the absence of TV in the carcinogenic and genetic effects has not been proved, ICRP employs the stochastic standpoint from the safety aspect for radioprotection. The lowest human TV known now is 100 mGy, meaning that human deterministic effect would not be generated below this dose. Genetic deterministic effect can be observable only in animal experiments. These facts suggest that the practical risk of exposure to <100 mGy in human is the carcinogenesis. The relationship between carcinogenic risk in A-bomb survivors and their exposed dose are found fitted to the linear no TV model, but the epidemiologic data, because of restriction of subject number analyzed, do not always mean that the model is applicable even below the dose <100 mGy. This would be one of confusing causes in explanation: no carcinogenic risk at <100 mGy or risk linear to dose even at <100 mGy, neither of which is scientifically conclusive at present. Also mentioned is the scarce risk of cancer in residents living in the high background radiation regions in the world in comparison with that in the A-bomb survivors exposed to the chronic or acute low dose/dose rate. Molecular events are explained for the low-dose radiation-induced DNA damage and its repair, gene mutation and chromosome aberration, hypothesis of carcinogenesis by mutation, and non-targeting effect of radiation (bystander effect and gene instability). Further researches to elucidate the low dose

  11. New evidence for the etiology of the so-called radiation caries. Proof for direct radiogenic damage of the dento-enamel junction

    International Nuclear Information System (INIS)

    Groetz, K.A.; Wagner, W.; Duschner, H.; Kutzner, J.; Thelen, M.

    1997-01-01

    Methods: A systematic study is presented, comparing teeth with a manifest radiation caries (group 1, about 60 Gy, long interval to the extraction) and clinically caries free teeth (group 2, about 30 Gy, short interval) with tooth specimens after an experimental enoral (in situ) irradiation (60 Gy, group 3) and after in vitro irradiation (500 to 2.500 Gy, group 4). 60 Co was the irradiation source. Sound teeth were used as a standard (group 5). For non destructive visualisation of subsurface histotomograms by confocal laser scanning microscopy (CLSM) teeth were either used as fresh sections or as Technovit embedded thin slices (sawing grinding technique). Results: Tooth samples from radiotherapy patients (cancer therapeutic doses, long interval before extraction; group 1) showed three characteristic changes: 1. Rarefication of the branching (ramification) of odontoblast processes near the junction, 2. dentine tubules end infront of the interface to the hard tissue and 3. in dentine the interface is characterised by a zone (about 10 μm wide) of low intensity of the remitted light. Conclusions: The obliteration of the dentine tubules, preceded by a degeneration of the odontoblast processes, is obviously the result of a direct radiogenic cell damage with hampered vascularisation and metabolism particularly in the area of the terminations of the odontoblast processes. The deficit in metabolism combined with a latent damage of the parenchyma (hypo-remitting zone) is evidence for the functional symptoms (subsurface caries). The prerequisite for the micromorphological manifestation of this direct irradiation damage is a vital tooth and in consequence cannot be simulated in situ or in vivo. (orig./MG) [de

  12. Cancer risk of low dose/low dose rate radiation: a meta-analysis of cancer data of mammals exposed to low doses of radiation

    International Nuclear Information System (INIS)

    Ogata, Hiromitsu; Magae, Junji

    2008-01-01

    Full text: Linear No Threshold (LNT) model is a basic theory for radioprotection, but the adaptability of this hypothesis to biological responses at low doses or at low dose rates is not sufficiently investigated. Simultaneous consideration of the cumulative dose and the dose rate is necessary for evaluating the risk of long-term exposure to ionizing radiation at low dose. This study intends to examine several numerical relationships between doses and dose rates in biological responses to gamma radiation. Collected datasets on the relationship between dose and the incidence of cancer in mammals exposed to low doses of radiation were analysed using meta-regression models and modified exponential (MOE) model, which we previously published, that predicts irradiation time-dependent biological response at low dose rate ionizing radiation. Minimum doses of observable risk and effective doses with a variety of dose rates were calculated using parameters estimated by fitting meta-regression models to the data and compared them with other statistical models that find values corresponding to 'threshold limits'. By fitting a weighted regression model (fixed-effects meta-regression model) to the data on risk of all cancers, it was found that the log relative risk [log(RR)] increased as the total exposure dose increased. The intersection of this regression line with the x-axis denotes the minimum dose of observable risk. These estimated minimum doses and effective doses increased with decrease of dose rate. The goodness of fits of MOE-model depended on cancer types, but the total cancer risk is reduced when dose rates are very low. The results suggest that dose response curve for cancer risk is remarkably affected by dose rate and that dose rate effect changes as a function of dose rate. For scientific discussion on the low dose exposure risk and its uncertainty, the term 'threshold' should be statistically defined, and dose rate effects should be included in the risk

  13. Dose-dependent hepatic transcriptional responses in Atlantic salmon (Salmo salar) exposed to sublethal doses of gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Song, You, E-mail: you.song@niva.no [Norwegian University of Life Sciences (NMBU), Faculty of Environmental Science and Technology, Department of Environmental Sciences (IMV), Centre for Environmental Radioactivity - CERAD, P.O. Box 5003, N-1432 Ås (Norway); Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, N-0349 Oslo (Norway); Salbu, Brit; Teien, Hans-Christian; Heier, Lene Sørlie [Norwegian University of Life Sciences (NMBU), Faculty of Environmental Science and Technology, Department of Environmental Sciences (IMV), Centre for Environmental Radioactivity - CERAD, P.O. Box 5003, N-1432 Ås (Norway); Rosseland, Bjørn Olav [Norwegian University of Life Sciences (NMBU), Faculty of Environmental Science and Technology, Department of Environmental Sciences (IMV), Centre for Environmental Radioactivity - CERAD, P.O. Box 5003, N-1432 Ås (Norway); Norwegian University of Life Sciences (NMBU), Department of Ecology and Natural Resource Management, P.O. Box 5003, N-1432 Ås (Norway); Tollefsen, Knut Erik [Norwegian University of Life Sciences (NMBU), Faculty of Environmental Science and Technology, Department of Environmental Sciences (IMV), Centre for Environmental Radioactivity - CERAD, P.O. Box 5003, N-1432 Ås (Norway); Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, N-0349 Oslo (Norway)

    2014-11-15

    affected DEGs associated with cellular signaling and immune response; 70 mGy radiation affected cell cycle regulation and DNA damage repair, cellular energy production; and 280 mGy radiation affected pathways related to cell cycle regulation and DNA repair, mitochondrial dysfunction and immune functions. Twelve genes representative of key pathways found in this study were verified by qPCR. Potential common MoAs of low-dose gamma radiation may include induction of oxidative stress, DNA damage and disturbance of oxidative phosphorylation (OXPHOS). Although common MoAs were proposed, a number of DEGs and pathways were still found to be dose-specific, potentially indicating multiple mechanisms of action (MOAs) of low-dose gamma radiation in fish. In addition, plasma glucose displayed an apparent increase with increasing radiation doses, although the results were not significantly different from the control. These findings suggested that sublethal doses of gamma radiation may cause dose-dependent transcriptional changes in the liver of Atlantic salmon after short-term exposure. The current study predicted multiple MoA for gamma radiation and may aid future impact assessment of environmental radioactivity in fish.

  14. Attenuation of 10 MeV electron beam energy to achieve low doses does not affect Salmonella spp. inactivation kinetics

    International Nuclear Information System (INIS)

    Hieke, Anne-Sophie Charlotte; Pillai, Suresh D.

    2015-01-01

    The effect of attenuating the energy of a 10 MeV electron beam on Salmonella inactivation kinetics was investigated. No statistically significant differences were observed between the D 10 values of either Salmonella 4,[5],12:i:- or a Salmonella cocktail (S. 4,[5],12:i:-, Salmonella Heidelberg, Salmonella Newport, Salmonella Typhimurium, Salmonella) when irradiated with either a non-attenuated 10 MeV eBeam or an attenuated 10 MeV eBeam (~2.9±0.22 MeV). The results show that attenuating the energy of a 10 MeV eBeam to achieve low doses does not affect the inactivation kinetics of Salmonella spp. when compared to direct 10 MeV eBeam irradiation. - Highlights: • 10 MeV eBeam energy was attenuated to 2.9±0.22 MeV using HDPE sheets. • Attenuation of eBeam energy does not affect the inactivation kinetics of Salmonella. • Microbial inactivation is independent of eBeam energy in the range of 3–10 MeV

  15. Labour cost of radiation dose

    International Nuclear Information System (INIS)

    Cook, A.; Lockett, L.E.

    1978-01-01

    In order to optimise capital expenditure on measures to protect workers against radiation it would be useful to have a means to measure radiation dose in money terms. Because labour has to be employed to perform radiation work there must be some relationship between the wages paid and the doses received. Where the next increment of radiation dose requires additional labour to be recruited the cost will at least equal the cost of the extra labour employed. This paper examines some of the factors which affect the variability of the labour cost of radiation dose and notes that for 'in-plant' exposures the current cost per rem appears to be significantly higher than values quoted in ICRP Publication 22. An example is given showing how this concept may be used to determine the capital it is worth spending on installed plant to prevent regular increments of radiation dose to workers. (author)

  16. Dose and dose rate effects of whole-body gamma-irradiation: II. Hematological variables and cytokines

    Science.gov (United States)

    Gridley, D. S.; Pecaut, M. J.; Miller, G. M.; Moyers, M. F.; Nelson, G. A.

    2001-01-01

    The goal of part II of this study was to evaluate the effects of gamma-radiation on circulating blood cells, functional characteristics of splenocytes, and cytokine expression after whole-body irradiation at varying total doses and at low- and high-dose-rates (LDR, HDR). Young adult C57BL/6 mice (n = 75) were irradiated with either 1 cGy/min or 80 cGy/min photons from a 60Co source to cumulative doses of 0.5, 1.5, and 3.0 Gy. The animals were euthanized at 4 days post-exposure for in vitro assays. Significant dose- (but not dose-rate-) dependent decreases were observed in erythrocyte and blood leukocyte counts, hemoglobin, hematocrit, lipopolysaccharide (LPS)-induced 3H-thymidine incorporation, and interleukin-2 (IL-2) secretion by activated spleen cells when compared to sham-irradiated controls (p factor-beta 1 (TGF-beta 1) and splenocyte secretion of tumor necrosis factor-alpha (TNF-alpha) were not affected by either the dose or dose rate of radiation. The data demonstrate that the responses of blood and spleen were largely dependent upon the total dose of radiation employed and that an 80-fold difference in the dose rate was not a significant factor in the great majority of measurements.

  17. Expression of Podoplanin in the Mouse Tooth Germ and Apical Bud Cells

    Science.gov (United States)

    Sawa, Yoshihiko; Iwasawa, Kana; Ishikawa, Hiroyuki

    2008-01-01

    This study was designed to investigate the distribution of cells expressing podoplanin in the mouse tooth bud. Podoplanin expression was detected in enamel epithelia of the cervical loop at cell-cell contacts strongly, and weakly on the loosely aggregated stellate reticulum in the center and the neighboring stratum intermedium. Odontoblasts exhibited intense podoplanin expression at the junction with predentin while no expression was detected in the enamel organ containing ameloblasts. These results suggest that proliferating inner and outer enamel epithelia express podoplanin but that the expression is suppressed in the differentiated epithelia containing ameloblasts. On the other hand the podoplanin expression occurs in the differentiating odontoblasts and the expression is sustained in differentiated odontoblasts, indicating that odontoblasts have the strong ability to express podoplanin. In cultured apical bud cells podoplanin was detected at cell-cell contacts. In real-time PCR analysis the amount of podoplanin mRNA of the apical buds was 2-fold compared with the amount of kidney used as a positive control. These findings indicate that apical bud cells have the strong ability to express the podoplanin gene. Podoplanin is a mucin-type glycoprotein negatively charged by extensive O-glycosylation and a high content of sialic acid, which expresses the adhesive property. The podoplanin may contribute to form odontoblastic fiber or function as the anchorage to the tooth development and in proliferating epithelial cells of cervical loop and apical bud. PMID:18989465

  18. Distribution of the amelogenin protein in developing, injured and carious human teeth

    Directory of Open Access Journals (Sweden)

    Thimios eMitsiadis

    2014-12-01

    Full Text Available Amelogenin is the major enamel matrix protein with key roles in amelogenesis. Although for many decades amelogenin was considered to be exclusively expressed by ameloblasts, more recent studies have shown that amelogenin is also expressed in other dental and no-dental cells. However, amelogenin expression in human tissues remains unclear. Here, we show that amelogenin protein is not only expressed during human embryonic development but also in pathological conditions such as carious lesions and injuries after dental cavity preparation. In developing embryonic teeth, amelogenin stage-specific expression is found in all dental epithelia cell populations but with different instensities. In the different layers of enamel matrix, waves of positive versus negative immunostaining for amelogenin are detected suggesting that the secretion of amelogenin protein is orchestreted by a biological clock. Amelogenin is also expressed transiently in differentiating odontoblasts during predentin formation, but was absent in mature functional odontoblasts. In intact adult teeth, amelogenin was not present in dental pulp, odontoblasts, and dentin. However, in injured and carious adult human teeth amelogenin is strongly re-expressed in newly differentiated odontoblasts and is distributed in the dentinal tubuli under the lesion site. In an in vitro culture system, amelogenin is expressed preferentially in human dental pulp cells that start differentiating into odontoblast-like cells and form mineralization nodules. These data suggest that amelogenin plays important roles not only during cytodifferentiation, but also during tooth repair processes in humans.

  19. Imaging dose in breast radiotherapy: does breast size affect the dose to the organs at risk and the risk of secondary cancer to the contralateral breast?

    International Nuclear Information System (INIS)

    Batumalai, Vikneswary; Quinn, Alexandra; Jameson, Michael; Delaney, Geoff; Holloway, Lois

    2015-01-01

    Correct target positioning is crucial for accurate dose delivery in breast radiotherapy resulting in utilisation of daily imaging. However, the radiation dose from daily imaging is associated with increased probability of secondary induced cancer. The aim of this study was to quantify doses associated with three imaging modalities and investigate the correlation of dose and varying breast size in breast radiotherapy. Planning computed tomography (CT) data sets of 30 breast cancer patients were utilised to simulate the dose received by various organs from a megavoltage computed tomography (MV-CT), megavoltage electronic portal image (MV-EPI) and megavoltage cone-beam computed tomography (MV-CBCT). The mean dose to organs adjacent to the target volume (contralateral breast, lungs, spinal cord and heart) were analysed. Pearson correlation analysis was performed to determine the relationship between imaging dose and primary breast volume and the lifetime attributable risk (LAR) of induced secondary cancer was calculated for the contralateral breast. The highest contralateral breast mean dose was from the MV-CBCT (1.79 Gy), followed by MV-EPI (0.22 Gy) and MV-CT (0.11 Gy). A similar trend was found for all organs at risk (OAR) analysed. The primary breast volume inversely correlated with the contralateral breast dose for all three imaging modalities. As the primary breast volume increases, the likelihood of a patient developing a radiation-induced secondary cancer to the contralateral breast decreases. MV-CBCT showed a stronger relationship between breast size and LAR of developing a radiation-induced contralateral breast cancer in comparison with the MV-CT and MV-EPI. For breast patients, imaging dose to OAR depends on imaging modality and treated breast size. When considering the use of imaging during breast radiotherapy, the patient's breast size and contralateral breast dose should be taken into account

  20. Radiation dose-reduction strategies in thoracic CT.

    Science.gov (United States)

    Moser, J B; Sheard, S L; Edyvean, S; Vlahos, I

    2017-05-01

    Modern computed tomography (CT) machines have the capability to perform thoracic CT for a range of clinical indications at increasingly low radiation doses. This article reviews several factors, both technical and patient-related, that can affect radiation dose and discusses current dose-reduction methods relevant to thoracic imaging through a review of current techniques in CT acquisition and image reconstruction. The fine balance between low radiation dose and high image quality is considered throughout, with an emphasis on obtaining diagnostic quality imaging at the lowest achievable radiation dose. The risks of excessive radiation dose reduction are also considered. Inappropriately low dose may result in suboptimal or non-diagnostic imaging that may reduce diagnostic confidence, impair diagnosis, or result in repeat examinations incurring incremental ionising radiation exposure. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  1. Absorbed dose by a CMOS in radiotherapy

    International Nuclear Information System (INIS)

    Borja H, C. G.; Valero L, C. Y.; Guzman G, K. A.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R.; Paredes G, L. C.

    2011-10-01

    Absorbed dose by a complementary metal oxide semiconductor (CMOS) circuit as part of a pacemaker, has been estimated using Monte Carlo calculations. For a cancer patient who is a pacemaker carrier, scattered radiation could damage pacemaker CMOS circuits affecting patient's health. Absorbed dose in CMOS circuit due to scattered photons is too small and therefore is not the cause of failures in pacemakers, but neutron calculations shown an absorbed dose that could cause damage in CMOS due to neutron-hydrogen interactions. (Author)

  2. Follow up on a workloaded interventional radiologist's occupational radiation doses - a study case

    International Nuclear Information System (INIS)

    Ketner, D.; Ofer, A.; Engel, A.

    2004-01-01

    During many interventional procedures, patients' radiation doses are high, affecting radiologist's radiation doses. We checked occupational doses of a workloaded interventional radiologist during seven years

  3. Dose and dose rate effects of whole-body gamma-irradiation: II. Hematological variables and cytokines

    Science.gov (United States)

    Gridley, D. S.; Pecaut, M. J.; Miller, G. M.; Moyers, M. F.; Nelson, G. A.

    2001-01-01

    The goal of part II of this study was to evaluate the effects of gamma-radiation on circulating blood cells, functional characteristics of splenocytes, and cytokine expression after whole-body irradiation at varying total doses and at low- and high-dose-rates (LDR, HDR). Young adult C57BL/6 mice (n = 75) were irradiated with either 1 cGy/min or 80 cGy/min photons from a 60Co source to cumulative doses of 0.5, 1.5, and 3.0 Gy. The animals were euthanized at 4 days post-exposure for in vitro assays. Significant dose- (but not dose-rate-) dependent decreases were observed in erythrocyte and blood leukocyte counts, hemoglobin, hematocrit, lipopolysaccharide (LPS)-induced 3H-thymidine incorporation, and interleukin-2 (IL-2) secretion by activated spleen cells when compared to sham-irradiated controls (p < 0.05). Basal proliferation of leukocytes in the blood and spleen increased significantly with increasing dose (p < 0.05). Significant dose rate effects were observed only in thrombocyte counts. Plasma levels of transforming growth factor-beta 1 (TGF-beta 1) and splenocyte secretion of tumor necrosis factor-alpha (TNF-alpha) were not affected by either the dose or dose rate of radiation. The data demonstrate that the responses of blood and spleen were largely dependent upon the total dose of radiation employed and that an 80-fold difference in the dose rate was not a significant factor in the great majority of measurements.

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

    International Nuclear Information System (INIS)

    Park, Sang Hyun

    2003-02-01

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

  5. Dose and dose rate effects of whole-body gamma-irradiation: I. Lymphocytes and lymphoid organs

    Science.gov (United States)

    Pecaut, M. J.; Nelson, G. A.; Gridley, D. S.

    2001-01-01

    The major goal of part I of this study was to compare varying doses and dose rates of whole-body gamma-radiation on lymphoid cells and organs. C57BL/6 mice (n = 75) were exposed to 0, 0.5, 1.5, and 3.0 Gy gamma-rays (60Co) at 1 cGy/min (low-dose rate, LDR) and 80 cGy/min (high-dose rate, HDR) and euthanized 4 days later. A significant dose-dependent loss of spleen mass was observed with both LDR and HDR irradiation; for the thymus this was true only with HDR. Decreasing leukocyte and lymphocyte numbers occurred with increasing dose in blood and spleen at both dose rates. The numbers (not percentages) of CD3+ T lymphocytes decreased in the blood in a dose-dependent manner at both HDR and LDR. Splenic T cell counts decreased with dose only in HDR groups; percentages increased with dose at both dose rates. Dose-dependent decreases occurred in CD4+ T helper and CD8+ T cytotoxic cell counts at HDR and LDR. In the blood the percentages of CD4+ cells increased with increasing dose at both dose rates, whereas in the spleen the counts decreased only in the HDR groups. The percentages of the CD8+ population remained stable in both blood and spleen. CD19+ B cell counts and percentages in both compartments declined markedly with increasing HDR and LDR radiation. NK1.1+ natural killer cell numbers and proportions remained relatively stable. Overall, these data indicate that the observed changes were highly dependent on the dose, but not dose rate, and that cells in the spleen are more affected by dose rate than those in blood. The results also suggest that the response of lymphocytes in different body compartments may be variable.

  6. The Effects of Irradiation and Calcium-deficient Diet on the Expression of Bone Morphogenetic Protein-2/4 during Early Tooth Development

    International Nuclear Information System (INIS)

    Park, Dai Hee; Hwang, Eui Hwan; Lee, Sang Rae

    2000-01-01

    To investigate the expression of bone morphogenetic protein (BMP)-2/4 during early tooth development after irradiation and calcium-deficient diet. The pregnant three-week-old Sprague-Dawley rats were used for the study. The control group was non-irradiation/normal diet group (Group 1), and the experimental groups were irradiation/normal diet group (Group 2) and irradiation/calcium-diet group (Group 3). The abdomen of the rats at the 9th day of pregnancy were irradiated with single dose of 350 cGy. The rat pups were sacrificed at embryonic 18 days, 3 days and 14 days after delivery and the maxillae tooth germs were taken. The tissue sections of specimen were stained immunohistochemically with anti-BMP-2/4 antibody. At embryo-18 days, immunoreacivity for BMP-2/4 of the Group 1 was modetate in stratum intermedium of dental organ and weak in dental papilla and dental follicle, but that of Group 2 was weak in cell layer of dental organ, and no immunoreacivity was shown in dental papilla and dental follice of Group 2 and in all tissue components of the Group 3. At postnatal-3 days, immunoreacivity for BMP-2/4 of the Group 1 was strong in cell layer of dental organ, odontoblasts and developing alveolar bone, but that of Group of 2 and Group 3 was weak in odontoblasts and developing alveolar bone. At postnatal-14 days, immunoreacivity for BMP-2/4 of the Group 1 was strong in newly formed cementum, alveolar bone and odontoblasts, but that of Group 2 was weaker than that of Group 1. In the Group 3, tooth forming cell layer showed weak immunoreactivity, but other cell layers showed no immunoreactivity. The expression of bone morphogenetic protein (BMP)-2/4 during early tooth development was disturbed after irradiation and calcium-deficient diet.

  7. The Effects of Irradiation and Calcium-deficient Diet on the Expression of Bone Morphogenetic Protein-2/4 during Early Tooth Development

    Energy Technology Data Exchange (ETDEWEB)

    Park, Dai Hee; Hwang, Eui Hwan; Lee, Sang Rae [Dept. of Oral and Maxillofacial Radiology, College of Dentistry, Kyunghee University, Seoul (Korea, Republic of)

    2000-09-15

    To investigate the expression of bone morphogenetic protein (BMP)-2/4 during early tooth development after irradiation and calcium-deficient diet. The pregnant three-week-old Sprague-Dawley rats were used for the study. The control group was non-irradiation/normal diet group (Group 1), and the experimental groups were irradiation/normal diet group (Group 2) and irradiation/calcium-diet group (Group 3). The abdomen of the rats at the 9th day of pregnancy were irradiated with single dose of 350 cGy. The rat pups were sacrificed at embryonic 18 days, 3 days and 14 days after delivery and the maxillae tooth germs were taken. The tissue sections of specimen were stained immunohistochemically with anti-BMP-2/4 antibody. At embryo-18 days, immunoreacivity for BMP-2/4 of the Group 1 was modetate in stratum intermedium of dental organ and weak in dental papilla and dental follicle, but that of Group 2 was weak in cell layer of dental organ, and no immunoreacivity was shown in dental papilla and dental follice of Group 2 and in all tissue components of the Group 3. At postnatal-3 days, immunoreacivity for BMP-2/4 of the Group 1 was strong in cell layer of dental organ, odontoblasts and developing alveolar bone, but that of Group of 2 and Group 3 was weak in odontoblasts and developing alveolar bone. At postnatal-14 days, immunoreacivity for BMP-2/4 of the Group 1 was strong in newly formed cementum, alveolar bone and odontoblasts, but that of Group 2 was weaker than that of Group 1. In the Group 3, tooth forming cell layer showed weak immunoreactivity, but other cell layers showed no immunoreactivity. The expression of bone morphogenetic protein (BMP)-2/4 during early tooth development was disturbed after irradiation and calcium-deficient diet.

  8. Dose estimation from residual and fallout radioactivity, 1

    International Nuclear Information System (INIS)

    Takeshita, Kenji

    1975-01-01

    External dose rates and cumulative doses for early entrants from areal surveys and simulated experiments are reviewed. The average cumulative doses to infinity at the hypocenters were 101 rad in Hiroshima and 32 rad in Nagasaki, with a variation of about 60 percent. Radioactive fallout areas nearly matched the ''black rain'' areas in Nagasaki and in Hiroshima. Radioactivity in the fallout areas was affected by radioactive decay and by the leaching and dissipation by rains. Considering these factors, the cumulative dose to infinity in the fallout area of Hiroshima was estimated to be 13 rad, excluding internal radiation doses from inhaled and ingested radionuclides. Attempts to estimate radiation dose from internally deposited radionuclides are also described. (auth.)

  9. Patient dose and risk in mammography

    International Nuclear Information System (INIS)

    Law, J.

    1991-01-01

    Patient dose in mammography is estimated by two methods compared and giving agreement. A mean tissue dose of about 1 mGy per film is found for a breast of 4.5 cm compressed thickness. Variables affecting dose are then considered quantitatively, including compressed breast thickness, tube potential, grids, magnification and beam collimation. The variables having the greatest effect are breast thickness and magnification. The dose estimates are combined with existing data on breast cancer induction to predict the risk of carcinogenesis in a breast screening programme. For example, in a screening centre performing 15 000 examinations per year, only one induced cancer is predicted in about 7 years of screening under average UK conditions of age and breast thickness. (author)

  10. Absorbed dose by a CMOS in radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Borja H, C. G.; Valero L, C. Y.; Guzman G, K. A.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L. C., E-mail: candy_borja@hotmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2011-10-15

    Absorbed dose by a complementary metal oxide semiconductor (CMOS) circuit as part of a pacemaker, has been estimated using Monte Carlo calculations. For a cancer patient who is a pacemaker carrier, scattered radiation could damage pacemaker CMOS circuits affecting patient's health. Absorbed dose in CMOS circuit due to scattered photons is too small and therefore is not the cause of failures in pacemakers, but neutron calculations shown an absorbed dose that could cause damage in CMOS due to neutron-hydrogen interactions. (Author)

  11. Low doses of ultraviolet-B or ultraviolet-C radiation affect phytohormones in young pea plants

    International Nuclear Information System (INIS)

    Ivanov, S.; Azmi, A.; Prinsen, E.; Van Onckelen, H.; Alexieva, V.; Katerova, Z.

    2009-01-01

    Pea (cv. Scinado) seedlings were exposed to low doses of ultraviolet-B (UV-B; 4.4 and 13.3 kJ/square m/d) or UV-C (0.1 and 0.3 kJ/square m/d) radiation for 14 d. Aminocyclopropane carboxylic acid (ACC), indoleacetic acid (IAA) and abscisic acid (ABA) concentrations were quantified by gas chromatography coupled to mass spectrometry. The accumulation of ACC upon irradiation was dose-dependent. ABA conc. was reduced and IAA conc. increased upon UV-C treatment, whereas the UV-B doses used did not cause significant changes in ABA and IAA levels

  12. Radiation dose rates from UF{sub 6} cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Friend, P.J. [Urenco, Capenhurst (United Kingdom)

    1991-12-31

    This paper describes the results of many studies, both theoretical and experimental, which have been carried out by Urenco over the last 15 years into radiation dose rates from uranium hexafluoride (UF{sub 6}) cylinders. The contents of the cylinder, its history, and the geometry all affect the radiation dose rate. These factors are all examined in detail. Actual and predicted dose rates are compared with levels permitted by IAEA transport regulations.

  13. Pediatric chest HRCT using the iDose4 Hybrid Iterative Reconstruction Algorithm: Which iDose level to choose?

    International Nuclear Information System (INIS)

    Smarda, M; Alexopoulou, E; Mazioti, A; Kordolaimi, S; Ploussi, A; Efstathopoulos, E; Priftis, K

    2015-01-01

    Purpose of the study is to determine the appropriate iterative reconstruction (IR) algorithm level that combines image quality and diagnostic confidence, for pediatric patients undergoing high-resolution computed tomography (HRCT). During the last 2 years, a total number of 20 children up to 10 years old with a clinical presentation of chronic bronchitis underwent HRCT in our department's 64-detector row CT scanner using the iDose IR algorithm, with almost similar image settings (80kVp, 40-50 mAs). CT images were reconstructed with all iDose levels (level 1 to 7) as well as with filtered-back projection (FBP) algorithm. Subjective image quality was evaluated by 2 experienced radiologists in terms of image noise, sharpness, contrast and diagnostic acceptability using a 5-point scale (1=excellent image, 5=non-acceptable image). Artifacts existance was also pointed out. All mean scores from both radiologists corresponded to satisfactory image quality (score ≤3), even with the FBP algorithm use. Almost excellent (score <2) overall image quality was achieved with iDose levels 5 to 7, but oversmoothing artifacts appearing with iDose levels 6 and 7 affected the diagnostic confidence. In conclusion, the use of iDose level 5 enables almost excellent image quality without considerable artifacts affecting the diagnosis. Further evaluation is needed in order to draw more precise conclusions. (paper)

  14. Effects of Chronic Low-Dose Radiation on Human Neural Progenitor Cells

    Science.gov (United States)

    Katsura, Mari; Cyou-Nakamine, Hiromasa; Zen, Qin; Zen, Yang; Nansai, Hiroko; Amagasa, Shota; Kanki, Yasuharu; Inoue, Tsuyoshi; Kaneki, Kiyomi; Taguchi, Akashi; Kobayashi, Mika; Kaji, Toshiyuki; Kodama, Tatsuhiko; Miyagawa, Kiyoshi; Wada, Youichiro; Akimitsu, Nobuyoshi; Sone, Hideko

    2016-01-01

    The effects of chronic low-dose radiation on human health have not been well established. Recent studies have revealed that neural progenitor cells are present not only in the fetal brain but also in the adult brain. Since immature cells are generally more radiosensitive, here we investigated the effects of chronic low-dose radiation on cultured human neural progenitor cells (hNPCs) derived from embryonic stem cells. Radiation at low doses of 31, 124 and 496 mGy per 72 h was administered to hNPCs. The effects were estimated by gene expression profiling with microarray analysis as well as morphological analysis. Gene expression was dose-dependently changed by radiation. By thirty-one mGy of radiation, inflammatory pathways involving interferon signaling and cell junctions were altered. DNA repair and cell adhesion molecules were affected by 124 mGy of radiation while DNA synthesis, apoptosis, metabolism, and neural differentiation were all affected by 496 mGy of radiation. These in vitro results suggest that 496 mGy radiation affects the development of neuronal progenitor cells while altered gene expression was observed at a radiation dose lower than 100 mGy. This study would contribute to the elucidation of the clinical and subclinical phenotypes of impaired neuronal development induced by chronic low-dose radiation.

  15. Biological responses to low dose rate gamma radiation

    International Nuclear Information System (INIS)

    Magae, Junji; Ogata, Hiromitsu

    2003-01-01

    Linear non-threshold (LNT) theory is a basic theory for radioprotection. While LNT dose not consider irradiation time or dose-rate, biological responses to radiation are complex processes dependent on irradiation time as well as total dose. Moreover, experimental and epidemiological studies that can evaluate LNT at low dose/low dose-rate are not sufficiently accumulated. Here we analyzed quantitative relationship among dose, dose-rate and irradiation time using chromosomal breakage and proliferation inhibition of human cells as indicators of biological responses. We also acquired quantitative data at low doses that can evaluate adaptability of LNT with statistically sufficient accuracy. Our results demonstrate that biological responses at low dose-rate are remarkably affected by exposure time, and they are dependent on dose-rate rather than total dose in long-term irradiation. We also found that change of biological responses at low dose was not linearly correlated to dose. These results suggest that it is necessary for us to create a new model which sufficiently includes dose-rate effect and correctly fits of actual experimental and epidemiological results to evaluate risk of radiation at low dose/low dose-rate. (author)

  16. Drug dosing in chronic kidney disease.

    Science.gov (United States)

    Gabardi, Steven; Abramson, Stuart

    2005-05-01

    Patients with chronic kidney disease (CKD) are at high risk for adverse drug reactions and drug-drug interactions. Drug dosing in these patients often proves to be a difficult task. Renal dysfunction-induced changes in human pathophysiology regularly results may alter medication pharmacodynamics and handling. Several pharmacokinetic parameters are adversely affected by CKD, secondary to a reduced oral absorption and glomerular filtration; altered tubular secretion; and reabsorption and changes in intestinal, hepatic, and renal metabolism. In general, drug dosing can be accomplished by multiple methods; however, the most common recommendations are often to reduce the dose or expand the dosing interval, or use both methods simultaneously. Some medications need to be avoided all together in CKD either because of lack of efficacy or increased risk of toxicity. Nevertheless, specific recommendations are available for dosing of certain medications and are an important resource, because most are based on clinical or pharmacokinetic trials.

  17. Radioiodine-131 treatment of thyrotoxicosis: Dose required for and some factors affecting the early induction of hypothyroidism

    International Nuclear Information System (INIS)

    Alevizaki, C.C.; Alevizaki-Harhalaki, M.C.; Ikkos, D.G.

    1985-01-01

    The results of 131 I treatment of thyrotoxicosis in 1,168 patients (302 males, 866 females; 58.5% diffuse and 41.5% multinodular toxic goitre) are presented. At the end of the 1st year post-treatment, 54.4% were hypothyroid, and the incidence of hypothyroidism after the 2nd year increased by 3% per year. When the results were analysed according to the calculated radiation dose the thyroid, it was found that the cumulative incidence of hypothyroidism from 6 months to 2 years post-treatment rose almost proportionally to the dose in cases of doses of 1,500-15,0000 rad, but increased very little for higher doses; however, the long-term incidence of hypothyroidism was almost independent of the thyroid dose. Multivariate analysis showed that the results of 131 I therapy at 6 months depended also on sex (treatment being more effective in women), the consistency of the thyroid gland and the year of treatment, with the same radiation dose giving a higher incidence of hypothyroidism in patients treated recently, in comparison to those treated in early in the period studied. Of the patients treated in the period 1978-1982 (mean dose, 300 μCi/g), 93.5% were cured with a single dose of 131 I, and 78% were hypothyroid at 6 months post-treatment. (orig.)

  18. Radioiodine-131 treatment of thyrotoxicosis: Dose required for and some factors affecting the early induction of hypothyroidism

    Energy Technology Data Exchange (ETDEWEB)

    Alevizaki, C C; Alevizaki-Harhalaki, M C; Ikkos, D G

    1985-05-01

    The results of /sup 131/I treatment of thyrotoxicosis in 1,168 patients (302 males, 866 females; 58.5% diffuse and 41.5% multinodular toxic goitre) are presented. At the end of the 1st year post-treatment, 54.4% were hypothyroid, and the incidence of hypothyroidism after the 2nd year increased by 3% per year. When the results were analysed according to the calculated radiation dose the thyroid, it was found that the cumulative incidence of hypothyroidism from 6 months to 2 years post-treatment rose almost proportionally to the dose in cases of doses of 1,500-15,0000 rad, but increased very little for higher doses; however, the long-term incidence of hypothyroidism was almost independent of the thyroid dose. Multivariate analysis showed that the results of /sup 131/I therapy at 6 months depended also on sex (treatment being more effective in women), the consistency of the thyroid gland and the year of treatment, with the same radiation dose giving a higher incidence of hypothyroidism in patients treated recently, in comparison to those treated in early in the period studied. Of the patients treated in the period 1978-1982 (mean dose, 300 ..mu..Ci/g), 93.5% were cured with a single dose of /sup 131/I, and 78% were hypothyroid at 6 months post-treatment.

  19. Occupational dose estimates for a monitored retrievable storage facility

    International Nuclear Information System (INIS)

    Harty, R.; Stoetzel, G.A.

    1986-06-01

    Occupational doses were estimated for radiation workers at the monitored retrievable storage (MRS) facility. This study provides an estimate of the occupational dose based on the current MRS facility design, examines the extent that various design parameters and assumptions affect the dose estimates, and identifies the areas and activities where exposures can be reduced most effectively. Occupational doses were estimated for both the primary storage concept and the alternate storage concept. The dose estimates indicate the annual dose to all radiation workers will be below the 5 rem/yr federal dose equivalent limit. However, the estimated dose to most of the receiving and storage crew (the workers responsible for the receipt, storage, and surveillance of the spent fuel and its subsequent retrieval), to the crane maintenance technicians, and to the cold and remote maintenance technicians is above the design objective of 1 rem/yr. The highest annual dose is received by the riggers (4.7 rem) in the receiving and storage crew. An indication of the extent to which various design parameters and assumptions affect the dose estimates was obtained by changing various design-based assumptions such as work procedures, background dose rates in radiation zones, and the amount of fuel received and stored annually. The study indicated that a combination of remote operations, increased shielding, and additional personnel (for specific jobs) or changes in operating procedures will be necessary to reduce worker doses below 1.0 rem/yr. Operations that could be made at least partially remote include the removal and replacement of the tiedowns, impact limiters, and personnel barriers from the shipping casks and the removal or installation of the inner closure bolts. Reductions of the background dose rates in the receiving/shipping and the transfer/discharge areas may be accomplished with additional shielding

  20. Considerations on absorbed dose estimates based on different β-dose point kernels in internal dosimetry

    International Nuclear Information System (INIS)

    Uchida, Isao; Yamada, Yasuhiko; Yamashita, Takashi; Okigaki, Shigeyasu; Oyamada, Hiyoshimaru; Ito, Akira.

    1995-01-01

    In radiotherapy with radiopharmaceuticals, more accurate estimates of the three-dimensional (3-D) distribution of absorbed dose is important in specifying the activity to be administered to patients to deliver a prescribed absorbed dose to target volumes without exceeding the toxicity limit of normal tissues in the body. A calculation algorithm for the purpose has already been developed by the authors. An accurate 3-D distribution of absorbed dose based on the algorithm is given by convolution of the 3-D dose matrix for a unit cubic voxel containing unit cumulated activity, which is obtained by transforming a dose point kernel into a 3-D cubic dose matrix, with the 3-D cumulated activity distribution given by the same voxel size. However, beta-dose point kernels affecting accurate estimates of the 3-D absorbed dose distribution have been different among the investigators. The purpose of this study is to elucidate how different beta-dose point kernels in water influence on the estimates of the absorbed dose distribution due to the dose point kernel convolution method by the authors. Computer simulations were performed using the MIRD thyroid and lung phantoms under assumption of uniform activity distribution of 32 P. Using beta-dose point kernels derived from Monte Carlo simulations (EGS-4 or ACCEPT computer code), the differences among their point kernels gave little differences for the mean and maximum absorbed dose estimates for the MIRD phantoms used. In the estimates of mean and maximum absorbed doses calculated using different cubic voxel sizes (4x4x4 mm and 8x8x8 mm) for the MIRD thyroid phantom, the maximum absorbed doses for the 4x4x4 mm-voxel were estimated approximately 7% greater than the cases of the 8x8x8 mm-voxel. They were found in every beta-dose point kernel used in this study. On the other hand, the percentage difference of the mean absorbed doses in the both voxel sizes for each beta-dose point kernel was less than approximately 0.6%. (author)

  1. Duration of high-dose aspirin therapy does not affect long-term coronary artery outcomes in Kawasaki disease.

    Science.gov (United States)

    Migally, Karl; Braunlin, Elizabeth A; Zhang, Lei; Binstadt, Bryce A

    2018-05-02

    BackgroundHigh-dose aspirin (HDA) is used with intravenous immunoglobulin (IVIg) in Kawasaki disease (KD). Practice regarding HDA varies, and it is unclear whether HDA duration affects the long-term course.MethodsWe retrospectively studied KD patients at our hospital for over 10 years. Patients were categorized as having received HDA for 0, 1-7, or >7 days. Primary outcome was the maximum coronary Z-score at diagnosis and follow-up; secondary outcomes included inflammatory markers.ResultsOne hundred and three patients had HDA duration documented, of which 35 patients had coronary artery abnormalities (CAAs) at diagnosis. There was no difference in demographics or inflammatory markers between the HDA groups, and no difference in HDA duration between patients with or without CAAs. Seventeen patients received no HDA; they had longer illness and defervescence duration before diagnosis, and were less likely to receive IVIg. For CAAs, multivariate regression revealed that HDA duration did not predict the coronary Z-score at 9-15 months. Higher Z-score at diagnosis was associated with higher Z-score at 9-15 months.ConclusionThe only factor associated with coronary Z-score at 9-15 months was the Z-score at diagnosis. At our institution, longer illness and defervescence duration and the lack of IVIg administration were associated with not administering HDA. HDA duration did not affect the clinically relevant outcomes, particularly CAA persistence.Pediatric Research advance online publication, 2 May 2018; doi:10.1038/pr.2018.44.

  2. Dose Response Model of Biological Reaction to Low Dose Rate Gamma Radiation

    International Nuclear Information System (INIS)

    Magae, J.; Furikawa, C.; Hoshi, Y.; Kawakami, Y.; Ogata, H.

    2004-01-01

    It is necessary to use reproducible and stable indicators to evaluate biological responses to long term irradiation at low dose-rate. They should be simple and quantitative enough to produce the results statistically accurate, because we have to analyze the subtle changes of biological responses around background level at low dose. For these purposes we chose micronucleus formation of U2OS, a human osteosarcoma cell line, as indicators of biological responses. Cells were exposed to gamma ray in irradiation rom bearing 50,000 Ci 60Co. After irradiation, they were cultured for 24 h in the presence of cytochalasin B to block cytokinesis, and cytoplasm and nucleus were stained with DAPI and prospidium iodide, respectively. the number of binuclear cells bearing micronuclei was counted under a fluorescence microscope. Dose rate in the irradiation room was measured with PLD. Dose response of PLD is linear between 1 mGy to 10 Gy, and standard deviation of triplicate count was several percent of mean value. We fitted statistically dose response curves to the data, and they were plotted on the coordinate of linearly scale response and dose. The results followed to the straight line passing through the origin of the coordinate axes between 0.1-5 Gy, and dose and does rate effectiveness factor (DDREF) was less than 2 when cells were irradiated for 1-10 min. Difference of the percent binuclear cells bearing micronucleus between irradiated cells and control cells was not statistically significant at the dose above 0.1 Gy when 5,000 binuclear cells were analyzed. In contrast, dose response curves never followed LNT, when cells were irradiated for 7 to 124 days. Difference of the percent binuclear cells bearing micronucleus between irradiated cells and control cells was not statistically significant at the dose below 6 Gy, when cells were continuously irradiated for 124 days. These results suggest that dose response curve of biological reaction is remarkably affected by exposure

  3. Lenalidomide at the dose of 25 mg every other day in patients affected by multiple myeloma and renal failure: a real-life experience.

    Science.gov (United States)

    Cerchione, Claudio; Nappi, Davide; Pareto, Anna E; Romano, Alessandra; Martinelli, Vincenzo; Picardi, Marco; Pane, Fabrizio; Catalano, Lucio

    2018-04-01

    Renal impairment (RI) is a relevant complication of patients affected by multiple myeloma (MM); it can be present in up to 30-35% of newly diagnosed MM and is linked to a poor outcome. However, early recognition and early treatment with novel agents can overcome the negative impact of RI and even reverse kidney damage in most cases. Lenalidomide, available as an oral compound, is an immunomodulatory drug with both antiproliferative and immunomodulatory activity that is largely used in the management of MM. Dose reduction is mandatory in RI; however, there is no theoretical assumption against the possibility that protracting the time of full standard doses can be equally effective and tolerated by patients requiring reduced doses. In this report, we describe our retrospective experience, in 18 patients, with the administration of lenalidomide 25 mg every other day for patients with MM and RI. The overall response ratio was 66.5%. More than half (61.1%) of the patients had a renal response. The median progression-free survival was 8 months (range: 3-18 months). No serious adverse event occurred during treatment, and it was never necessary to disrupt or delay treatment for toxicity. These preliminary observations point to a significant therapeutic effect of lenalidomide, at the dose of 25 mg every other day for 21 days, with logistic and economic advantages. However, these results should be validated by controlled studies involving larger numbers of patients.

  4. Low-dose aspartame consumption differentially affects gut microbiota-host metabolic interactions in the diet-induced obese rat.

    Science.gov (United States)

    Palmnäs, Marie S A; Cowan, Theresa E; Bomhof, Marc R; Su, Juliet; Reimer, Raylene A; Vogel, Hans J; Hittel, Dustin S; Shearer, Jane

    2014-01-01

    Aspartame consumption is implicated in the development of obesity and metabolic disease despite the intention of limiting caloric intake. The mechanisms responsible for this association remain unclear, but may involve circulating metabolites and the gut microbiota. Aims were to examine the impact of chronic low-dose aspartame consumption on anthropometric, metabolic and microbial parameters in a diet-induced obese model. Male Sprague-Dawley rats were randomized into a standard chow diet (CH, 12% kcal fat) or high fat (HF, 60% kcal fat) and further into ad libitum water control (W) or low-dose aspartame (A, 5-7 mg/kg/d in drinking water) treatments for 8 week (n = 10-12 animals/treatment). Animals on aspartame consumed fewer calories, gained less weight and had a more favorable body composition when challenged with HF compared to animals consuming water. Despite this, aspartame elevated fasting glucose levels and an insulin tolerance test showed aspartame to impair insulin-stimulated glucose disposal in both CH and HF, independently of body composition. Fecal analysis of gut bacterial composition showed aspartame to increase total bacteria, the abundance of Enterobacteriaceae and Clostridium leptum. An interaction between HF and aspartame was also observed for Roseburia ssp wherein HF-A was higher than HF-W (Paspartame attenuated the typical HF-induced increase in the Firmicutes:Bacteroidetes ratio. Serum metabolomics analysis revealed aspartame to be rapidly metabolized and to be associated with elevations in the short chain fatty acid propionate, a bacterial end product and highly gluconeogenic substrate, potentially explaining its negative affects on insulin tolerance. How aspartame influences gut microbial composition and the implications of these changes on the development of metabolic disease require further investigation.

  5. Characteristics of natural background external radiation and effective dose equivalent

    International Nuclear Information System (INIS)

    Fujimoto, Kenzo

    1989-01-01

    The two sources of natural radiation - cosmic rays and primordial radionuclides - are described. The factors affecting radiation doses received from natural radiation and the calculation of effective dose equivalent due to natural radiation are discussed. 10 figs., 3 tabs

  6. Childhood adversity specificity and dose-response effect in non-affective first-episode psychosis

    DEFF Research Database (Denmark)

    Trauelsen, Anne Marie; Bendall, Sarah; Jansen, Jens Einar

    2015-01-01

    BACKGROUND: Reviews conclude that childhood and adolescence sexual, physical, emotional abuse and emotional and physical neglect are all risk factors for psychosis. However, studies suggest only some adversities are associated with psychosis. Dose-response effects of several adversities on risk......% of the control group. Childhood and adolescent sexual, physical, emotional abuse, and physical and emotional neglect, separation and institutionalization were about four to 17 times higher for the FEP group (all p... of psychosis have not been consistently found. The current study aimed to explore adversity specificity and dose-response effects of adversities on risk of psychosis. METHOD: Participants were 101 persons with first-episode psychosis (FEP) diagnosed with ICD-10 F20 - F29 (except F21) and 101 non-clinical...

  7. Nordic Guidance Levels for Patient Doses in Diagnostic Radiology

    International Nuclear Information System (INIS)

    Saxebol, G.; Olerud, H.M.; Hjardemaal, O.; Leitz, W.; Servomaa, A.; Walderhaug, T.

    1998-01-01

    Within the framework of Nordic authoritative cooperation in radiation protection and nuclear safety, recommendations have been prepared dealing with dose constraints in diagnostic radiology. A working group with participants from all the Nordic countries has met and discussed possible implementations of the ICRP dose constraint for medical radiology. Dose constraints, expressed as guidance levels, were specified for six different radiological examinations, i.e. chest, pelvis, lumbar spine, urography, barium meal and enema in units of kerma-area product and entrance surface dose. The recommendations are described in report No 5 in the series 'Report on Nordic Radiation Protection Cooperation'. Examples of dose distributions and factors affecting the patient dose are described in the report. (author)

  8. Investigation of the dose rate dependency of the PAGAT gel dosimeter at low dose rates

    International Nuclear Information System (INIS)

    Zehtabian, M.; Faghihi, R.; Zahmatkesh, M.H.; Meigooni, A.S.; Mosleh-Shirazi, M.A.; Mehdizadeh, S.; Sina, S.; Bagheri, S.

    2012-01-01

    Medical physicists need dosimeters such as gel dosimeters capable of determining three-dimensional dose distributions with high spatial resolution. To date, in combination with magnetic resonance imaging (MRI), polyacrylamide gel (PAG) polymers are the most promising gel dosimetry systems. The purpose of this work was to investigate the dose rate dependency of the PAGAT gel dosimeter at low dose rates. The gel dosimeter was used for measurement of the dose distribution around a Cs-137 source from a brachytherapy LDR source to have a range of dose rates from 0.97 Gy h −1 to 0.06 Gy h −1 . After irradiation of the PAGAT gel, it was observed that the dose measured by gel dosimetry was almost the same at different distances (different dose rates) from the source, although the points nearer the source had been expected to receive greater doses. Therefore, it was suspected that the PAGAT gel is dose rate dependent at low dose rates. To test this further, three other sets of measurements were performed by placing vials containing gel at different distances from a Cs-137 source. In the first two measurements, several plastic vials were exposed to equal doses at different dose rates. An ionization chamber was used to measure the dose rate at each distance. In addition, three TLD chips were simultaneously irradiated in order to verify the dose to each vial. In the third measurement, to test the oxygen diffusion through plastic vials, the experiment was repeated again using plastic vials in a nitrogen box and glass vials. The study indicates that oxygen diffusion through plastic vials for dose rates lower than 2 Gy h −1 would affect the gel dosimeter response and it is suggested that the plastic vials or (phantoms) in an oxygen free environment or glass vials should be used for the dosimetry of low dose rate sources using PAGAT gel to avoid oxygen diffusion through the vials.

  9. Radiation dose estimates for radiopharmaceuticals

    International Nuclear Information System (INIS)

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

    1996-04-01

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

  10. Microbeams, microdosimetry and specific dose

    International Nuclear Information System (INIS)

    Randers-Pehrson, H.

    2002-01-01

    Dose and its usefulness as a single parameter to describe the amount of radiation absorbed are well established for most situations. The conditions where the concept of dose starts to break down are well known, mostly from the study of microdosimetry. For low doses of high LET radiation it is noted that the process of taking the limiting value of the energy absorbed within a test volume divided by the mass within that volume yields either zero or a relatively large value. The problem is further exacerbated with microbeam irradiations where the uniformity of the energy deposition is experimentally manipulated on the spatial scale of cells being irradiated. Booz introduced a quantity to deal with these problems: the unfortunately named 'mean specific energy in affected volumes'. This quantity multiplied by the probability that a test volume has received an energy deposit is equal to dose (in situations where dose can be defined). I propose that Booz's quantity be renamed 'specific dose', that is the mean energy deposited divided by the mass within a specified volume. If we believe for instance that the nucleus of a cell is the critical volume for biological effects, we can refer to the nuclear specific dose. A microbeam experiment wherein 10 per cent of the cell nuclei were targeted with 10 alpha particles would be described as delivering a nuclear specific dose of 1.6 Gy to 10 per cent of the population. (author)

  11. Dose-response characteristics of an amorphous silicon EPID

    International Nuclear Information System (INIS)

    Winkler, Peter; Hefner, Alfred; Georg, Dietmar

    2005-01-01

    Electronic portal imaging devices (EPIDs) were originally developed for the purpose of patient setup verification. Nowadays, they are increasingly used as dosimeters (e.g., for IMRT verification and linac-specific QA). A prerequisite for any clinical dosimetric application is a detailed understanding of the detector's dose-response behavior. The aim of this study is to investigate the dosimetric properties of an amorphous silicon EPID (Elekta IVIEWGT) with respect to three photon beam qualities: 6, 10, and 25 MV. The EPID showed an excellent temporal stability on short term as well as on long term scales. The stability throughout the day was strongly influenced by warming up, which took several hours and affected EPID response by 2.5%. Ghosting effects increased the sensitivity of the EPID. They became more pronounced with decreasing time intervals between two exposures as well as with increasing dose. Due to ghosting, changes in pixel sensitivity amounted up to 16% (locally) for the 25 MV photon beam. It was observed that the response characteristics of our EPID depended on dose as well as on dose rate. Doubling the dose rate increased the EPID sensitivity by 1.5%. This behavior was successfully attributed to a dose per frame effect, i.e., a nonlinear relationship between the EPID signal and the dose which was delivered to the panel between two successive readouts. The sensitivity was found to vary up to 10% in the range of 1 to 1000 monitor units. This variation was governed by two independent effects. For low doses, the EPID signal was reduced due to the linac's changing dose rate during startup. Furthermore, the detector reading was influenced by intrabeam variations of EPID sensitivity, namely, an increase of detector response during uniform exposure. For the beam qualities which were used, the response characteristics of the EPID did not depend on energy. Differences in relative dose-response curves resulted from energy dependent temporal output

  12. Dose-dependency of radiation on enzyme production in Trichoderma reesei

    International Nuclear Information System (INIS)

    Kumakura, Minoru

    1993-01-01

    Effect of irradiation dose on the production of cellulase and amylase related enzymes in Trichoderma reesei was studied in which post-irradiation time response pattern was measured. The damage of the cells irradiated with certain irradiation doses (1.40±0.20x10 5 , 2.20±0.10x10 5 , 3.00±0.50x10 5 and 3.50±0.20x10 5 rad) was rapidly recovered. The increased enzyme production in the culture of the irradiated cells resulted from the recovery of radiation damage after irradiation. The function of cell growth was not affected by irradiation below dose of 5x10 5 rad, though the function of enzyme synthesis was drastically affected. (orig.)

  13. Long term exposure to low dose neurotoxic pesticides affects hatching, viability and cholinesterase activity of Artemia sp.

    Science.gov (United States)

    Gambardella, Chiara; Nichino, Daniela; Iacometti, Camillo; Ferrando, Sara; Falugi, Carla; Faimali, Marco

    2018-03-01

    The brine shrimp Artemia was used as a model organism to test toxicity of several neuroactive pesticides (chlorpyrifos (CLP), chlorpyrifos oxon (CLP ox), diazinon (DZN), carbaryl (CBR)) following exposure to far below than lethal doses. Cysts were exposed to the pesticides in order to test a scenario similar to actual coastal environment contamination, by analyzing different responses. Cysts were rehydrated in water containing the pesticides at concentrations ranging from 10 -11 to 10 -5  M, for 72, 96 and 192 h, respectively. For these exposure times, morpho-functional and biochemical parameters, such as hatching speed and viability were investigated in the larvae together with cholinesterase (ChE) activity quantification and histochemical localization. Finally, ChE inhibition was also compared with conventional selective ChE inhibitors. Results showed that CLP ox and CBR caused a significant dose-dependent decrease in hatching speed, followed by high percentages of larval death, while CLP and DZN were responsible for irregular hatching patterns. In addition, the pesticides mostly caused larval death some days post-hatching, whereas this effect was negligible for the specific ChE inhibitors, suggesting that part of pesticide toxicity may be due to molecules other than the primary target. ChE activity was observed in the protocerebrum lobes, linked to the development of pair eyes. Such activity was inhibited in larvae exposed to all pesticides. When compared to conventional selective inhibitors of ChE activities, this inhibition demonstrated that the selected pesticides mainly affect acetylcholinesterase and, to a lesser extent, pseudocholinesterases. In conclusion, the brine shrimp is a good model to test the environmental toxicity of long term exposure to cholinergic pesticides, since changes in hatching speed, viability and ChE activity were observed. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Low-dose aspartame consumption differentially affects gut microbiota-host metabolic interactions in the diet-induced obese rat.

    Directory of Open Access Journals (Sweden)

    Marie S A Palmnäs

    Full Text Available Aspartame consumption is implicated in the development of obesity and metabolic disease despite the intention of limiting caloric intake. The mechanisms responsible for this association remain unclear, but may involve circulating metabolites and the gut microbiota. Aims were to examine the impact of chronic low-dose aspartame consumption on anthropometric, metabolic and microbial parameters in a diet-induced obese model. Male Sprague-Dawley rats were randomized into a standard chow diet (CH, 12% kcal fat or high fat (HF, 60% kcal fat and further into ad libitum water control (W or low-dose aspartame (A, 5-7 mg/kg/d in drinking water treatments for 8 week (n = 10-12 animals/treatment. Animals on aspartame consumed fewer calories, gained less weight and had a more favorable body composition when challenged with HF compared to animals consuming water. Despite this, aspartame elevated fasting glucose levels and an insulin tolerance test showed aspartame to impair insulin-stimulated glucose disposal in both CH and HF, independently of body composition. Fecal analysis of gut bacterial composition showed aspartame to increase total bacteria, the abundance of Enterobacteriaceae and Clostridium leptum. An interaction between HF and aspartame was also observed for Roseburia ssp wherein HF-A was higher than HF-W (P<0.05. Within HF, aspartame attenuated the typical HF-induced increase in the Firmicutes:Bacteroidetes ratio. Serum metabolomics analysis revealed aspartame to be rapidly metabolized and to be associated with elevations in the short chain fatty acid propionate, a bacterial end product and highly gluconeogenic substrate, potentially explaining its negative affects on insulin tolerance. How aspartame influences gut microbial composition and the implications of these changes on the development of metabolic disease require further investigation.

  15. Low-dose effects of hormones and endocrine disruptors.

    Science.gov (United States)

    Vandenberg, Laura N

    2014-01-01

    Endogenous hormones have effects on tissue morphology, cell physiology, and behaviors at low doses. In fact, hormones are known to circulate in the part-per-trillion and part-per-billion concentrations, making them highly effective and potent signaling molecules. Many endocrine-disrupting chemicals (EDCs) mimic hormones, yet there is strong debate over whether these chemicals can also have effects at low doses. In the 1990s, scientists proposed the "low-dose hypothesis," which postulated that EDCs affect humans and animals at environmentally relevant doses. This chapter focuses on data that support and refute the low-dose hypothesis. A case study examining the highly controversial example of bisphenol A and its low-dose effects on the prostate is examined through the lens of endocrinology. Finally, the chapter concludes with a discussion of factors that can influence the ability of a study to detect and interpret low-dose effects appropriately. © 2014 Elsevier Inc. All rights reserved.

  16. Sensibility of Teeth Having Based versus Non-Based Amalgam Restorations: A Clinical Study.

    Science.gov (United States)

    1983-04-01

    50:129-34, Apr. 1980. 102. Morrant, G. Dental instrumentation and pulpal injury: clinical considerations. Brit. Endodont . Soc. J., 10:3-8, 55-63...on the teeth are suspected mechanisms. In general, the effects of rotary cavity preparations--cutting of dentinal tubules and odontoblastic processes...aspiration of odontoblasts is of no consequence to the pulp providing the cells in the cell rich zone are intact. The idea that heat production from rotary

  17. Immunogenicity to poliovirus type 2 following two doses of fractional intradermal inactivated poliovirus vaccine: A novel dose sparing immunization schedule.

    Science.gov (United States)

    Anand, Abhijeet; Molodecky, Natalie A; Pallansch, Mark A; Sutter, Roland W

    2017-05-19

    The polio eradication endgame strategic plan calls for the sequential removal of Sabin poliovirus serotypes from the trivalent oral poliovirus vaccine (tOPV), starting with type 2, and the introduction of ≥1 dose of inactivated poliovirus vaccine (IPV), to maintain an immunity base against poliovirus type 2. The global removal of oral poliovirus type 2 was successfully implemented in May 2016. However, IPV supply constraints has prevented introduction in 21 countries and led to complete stock-out in >20 countries. We conducted a literature review and contacted corresponding authors of recent studies with fractional-dose IPV (fIPV), one-fifth of intramuscular dose administered intradermally, to conduct additional type 2 immunogenicity analyses of two fIPV doses compared with one full-dose IPV. Four studies were identified that assessed immunogenicity of two fIPV doses compared to one full-dose IPV. Two fractional doses are more immunogenic than 1 full-dose, with type 2 seroconversion rates improving between absolute 19-42% (median: 37%, pvaccine compared to one full-dose IPV. In response to the current IPV shortage, a schedule of two fIPV doses at ages 6 and 14weekshas been endorsed by technical oversight committees and has been introduced in some affected countries. Copyright © 2017. Published by Elsevier Ltd.

  18. Quality Control in Mammography: Image Quality and Patient Doses

    International Nuclear Information System (INIS)

    Ciraj Bjelac, O.; Arandjic, D.; Boris Loncar, B.; Kosutic, D.

    2008-01-01

    Mammography is method of choice for early detection of breast cancer. The purpose of this paper is preliminary evaluation the mammography practice in Serbia, in terms of both quality control indicators, i.e. image quality and patient doses. The survey demonstrated considerable variations in technical parameters that affect image quality and patients doses. Mean glandular doses ranged from 0.12 to 2.8 mGy, while reference optical density ranged from 1.2 to 2.8. Correlation between image contrast and mean glandular doses was demonstrated. Systematic implementation of quality control protocol should provide satisfactory performance of mammography units and maintain satisfactory image quality and keep patient doses as low as reasonably practicable. (author)

  19. Effects of low-dose recombinant human erythropoietin treatment on cognitive performance

    DEFF Research Database (Denmark)

    Viuff, Søren Lundgaard; Plenge, Ulla; Belhage, Bo

    2017-01-01

    , NUFI or self-reported results between the groups. CONCLUSIONS: In this small study, we found no significant effect of low-dose or micro-dose rhEpo on visual attention, cognitive performance in complex cognitive tasks or self-experienced cognitive performance compared with placebo. FUNDING: The Aase......INTRODUCTION: High-dose recombinant human erythropoietin (rhEpo) has been shown to improve cognitive performance in both healthy volunteers and in patients suffering from diseases affecting the brain. The aim of this study was to examine whether administration of low-dose and even micro-dose rh...

  20. Effects of low-dose recombinant human erythropoietin treatment on cognitive performance

    DEFF Research Database (Denmark)

    Viuff, Søren Lundgaard; Plenge, Ulla; Belhage, Bo

    2017-01-01

    -reported results between the groups. Conclusions: In this small study, we found no significant effect of low-dose or micro-dose rhEpo on visual attention, cognitive performance in complex cognitive tasks or self-experienced cognitive performance compared with placebo. Funding: The Aase and Ejnar Danielsen......Introduction: High-dose recombinant human erythropoietin (rhEpo) has been shown to improve cognitive performance in both healthy volunteers and in patients suffering from diseases affecting the brain. The aim of this study was to examine whether administration of low-dose and even micro-dose rh...

  1. Computed radiography dose optimization in pediatric patients

    International Nuclear Information System (INIS)

    Juste, B.; Verdu, G.; Tortosa, R.; Villaescusa, J.I.

    2008-01-01

    Radiation dose reduction in pediatric X-ray imaging is especially important because of children radiation sensitivity. For any radiographic examination performed at a fixed radiographic tube potential, the patient absorbed dose is directly proportional to the value of milliampere-seconds (mAs) selected by the operator. Nevertheless, reducing X-ray exposure has the unavoidable disadvantage of increasing the quantum noise in the resultant image. The objective of this work is to identify the minimum tube current setting required for maintaining accurate examinations, to modify, if required, the daily protocols applied at La Fe de Valencia Universitary Hospital. To accomplish this goal, a noise addition software has been developed in order to study the diagnostic accuracy as a function of reducing dose by artificially increasing the image noise. The noise addition tool has been applied to several thorax images acquired from pediatric unit to simulate new lower dose radiographies and allow medical researchers to study how lower dose affects the patient pneumonia diagnosis. (author)

  2. The assessment of personal dose due to external radiation

    International Nuclear Information System (INIS)

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

    1990-01-01

    The fundamental basis of thermoluminescent dosimetry (TLD) is discussed and a number of considerations in the measurement of thermoluminescence described, with particular reference to CaSO 4 :Dy. The steps taken to convert a thermoluminescence measurement to an exposure and then an absorbed dose are outlined. The calculation of effective dose equivalents due to external exposure to γ-radiation in a number of situations commonly encountered in a uranium mine is discussed. Factors which may affect the accuracy of external dose assessments are described

  3. Recollections of a Dental Researcher. Fifty Years at the U.S. National Bureau of Standards: Interviews with George C. Paffenbarger, DDS,

    Science.gov (United States)

    1980-10-01

    firm, practicing Methodists who frowned upon dancing and cardplaying. No alcohol was allowed in our home, and tobacco use was forbidden. (They had...theater where, ! l in a rear seat, he appar- nt1 ,; fell asleep and peacefully passed away (4). -"Eve since the early 1900’s, when Hunter and Billings...C and dental health, and showed that the first visible manifestation of the lack of Vitamin C was the odontoblast. The odontoblast was the first cell

  4. Ultra-low Dose CT for Attenuation Correction of 82Rb Cardiac PET

    DEFF Research Database (Denmark)

    Sørensen, Maria Balshøj; Bouchelouche, Kirsten; Tolbod, Lars Poulsen

    Aim: Myocardial perfusion imaging (MPI) using cardiac PET with tracers like 82Rb and 15O-water is substantially lower in radiation dose than classic MIBI-based SPECT. However, for cardiac PET, the dose contribution of CT for attenuation correction (CTAC) is typically 20-30% of the total dose....... To reduce the total radiation dose of cardiac PET further, we set out to examine if the use of ultra-low dose CTAC (UL-CTAC) would affect the accuracy of the quantitative parameters related to MPI. Furthermore, we examined whether the low quality of the UL-CTAC would affect the technologist’s ability...... to perform manual adjustment for misalignment between PET and CTAC. The CT reconstruction algorithm Q.AC was used to improve quality and consistency of the CTAC. Method: 23 consecutive clinical patients (BMI: 26.9 [range: 15.4-38.8]) referred for 82Rb PET rest and stress imaging were included in the study...

  5. Doses to worker groups in the nuclear industry

    International Nuclear Information System (INIS)

    Khan, T.; Baum, J.W.

    1992-01-01

    This article presents some of the results of a study carried out at the Brookhaven National Laboratory's ALARA Center on doses to various worker groups in the U.S. nuclear industry. In this study, data from workers in the industry were divided into male and female groups; the average radiation dose of these tow groups and the correlation of dose with age are presented. The male and female workers were further considered in the various sectors of the industry, and correlations of dose with age for each sector were investigated. For male workers, a downward correlation with age was observed, while for women there appeared to be a slight upward correlation. Data form 13 PWR and 9 BWR plants shows that a small, but important, group of workers would be affected by the NCRP proposed constraint of workers' lifetime dose in rem being maintained less than their ages. Various techniques proposed by the plants to reduce dose to this critical group of workers are also presented

  6. How does the chemistry of polymer gel dosimeters affect their performance?

    International Nuclear Information System (INIS)

    Jirasek, A; McAuley, K B; Lepage, M

    2009-01-01

    This review article describes the primary chemical processes affecting polymerization in polymer-based radiosensitive gel dosimeters. Furthermore, recently studied environmental factors and gelation processes affecting polymerization and gel dose response are discussed. Finally, the predominant physical factors affecting dose-response sensitivity for each of the three imaging modalities (MRI, Optical CT, x-ray CT) are outlined. Emphasis is concentrated on recent literature in this area, as prior literature was summarized in review articles submitted to DOSGEL 2006 in Sherbrooke (J. Conf. Series, 56, 2006). Discussions from the recent DOSGEL conference (2008) are incorporated into this review.

  7. How does the chemistry of polymer gel dosimeters affect their performance?

    Energy Technology Data Exchange (ETDEWEB)

    Jirasek, A [Department of Physics and Astronomy, University of Victoria, Victoria BC V8W 3P6 (Canada); McAuley, K B [Department of Chemical Engineering, Queen' s University, Kingston ON K7L 3N6 (Canada); Lepage, M [Centre d' imagerie moleculaire de Sherbrooke, Universite de Sherbrooke, 3001 12e Avenue Nord, Sherbrooke QC J1H 5N4 (Canada)], E-mail: jirasek@uvic.ca, E-mail: kim.mcauley@chee.queensu.ca, E-mail: martin.lepage@usherbrooke.ca

    2009-05-01

    This review article describes the primary chemical processes affecting polymerization in polymer-based radiosensitive gel dosimeters. Furthermore, recently studied environmental factors and gelation processes affecting polymerization and gel dose response are discussed. Finally, the predominant physical factors affecting dose-response sensitivity for each of the three imaging modalities (MRI, Optical CT, x-ray CT) are outlined. Emphasis is concentrated on recent literature in this area, as prior literature was summarized in review articles submitted to DOSGEL 2006 in Sherbrooke (J. Conf. Series, 56, 2006). Discussions from the recent DOSGEL conference (2008) are incorporated into this review.

  8. Effects of gamma radiation on hard dental tissues of albino rats: investigation by light microscopy.

    Science.gov (United States)

    El-Faramawy, Nabil; Ameen, Reham; El-Haddad, Khaled; El-Zainy, Medhat

    2013-08-01

    The present work aims at studying the effect of gamma radiation on the hard dental tissues. Eighty adult male albino rats with weights of about 250 g were used. The rats were irradiated at 0.2, 0.5, 1.0, 2.0, 4.0 and 6.0 Gy whole-body gamma doses. The effects on hard dental tissue samples were investigated after 48 h in histological and ground sections using light microscopy. Areas of acid phosphatase activity were detected using tartrate-resistant acid phosphatase (TRAP) stains. Observation of histological sections revealed disturbance in predentin thickness and odontoblastic layer as the irradiation dose increased. In cementum, widened cementocytes lacunae were occasionally detected even with low irradiated doses. On the other hand, relatively homogenous enamel was detected with darkened areas in enamel surface at doses over than 0.5 Gy. TRAP-positive cells were detected on the surface of the dentin of irradiated groups as well as cementum surface. Minimal detectable changes were observed in ground sections.

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

    International Nuclear Information System (INIS)

    Ma, C-M; Li Jinsheng

    2011-01-01

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

  10. The effect of source-axis distance on integral dose: implications for IMRT

    International Nuclear Information System (INIS)

    Keall, P.

    2001-01-01

    The source-axis distance (SAD) is a treatment machine design parameter that affects integral dose, dose rate and patient clearance. The aim of this work was to investigate the effect of source-axis distance on integral dose for conformal arc therapy. This work is part of a larger project to determine the ideal characteristics of a dedicated IMRT machine. The sensitivity of SAD to beam energy, PTV size, body size and PTV position were determined for conformal arc therapy. For the calculations performed here it was assumed that dose equals terma. The integral dose ratio (IDR) was used to quantify the calculation results. It was found that the IDR increases as both SAD and photon energy increase, though the dependence of IDR on SAD decreases as energy increases. The PTV size was found to have a negligible effect on the relationship between the SAD and IDR, however the body size does affect the relationship between the SAD and IDR. The position of the PTV within the body also affects the IDR. From dosimetric considerations alone, the larger the SAD, the better the possible dose distribution. The IDR for a very large SAD is increased by approximately 5% when compared with the IDR for 100 cm SAD. Similarly, the IDR for 100 cm SAD is approximately 5% higher than the IDR at 50 cm SAD. Copyright (2001) Australasian College of Physical Scientists and Engineers in Medicine

  11. Atmospheric radiation flight dose rates

    Science.gov (United States)

    Tobiska, W. K.

    2015-12-01

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

  12. Dose-dependent effects of endotoxin on neurobehavioral functions in humans.

    Directory of Open Access Journals (Sweden)

    Jan-Sebastian Grigoleit

    Full Text Available Clinical and experimental evidence document that inflammation and increased peripheral cytokine levels are associated with depression-like symptoms and neuropsychological disturbances in humans. However, it remains unclear whether and to what extent cognitive functions like memory and attention are affected by and related to the dose of the inflammatory stimulus. Thus, in a cross-over, double-blind, experimental approach, healthy male volunteers were administered with either placebo or bacterial lipopolysaccharide (LPS at doses of 0.4 (n = 18 or 0.8 ng/kg of body weight (n = 16. Pro- and anti-inflammatory cytokines, norephinephrine and cortisol concentrations were analyzed before and 1, 1.75, 3, 4, 6, and 24 h after injection. In addition, changes in mood and anxiety levels were determined together with working memory (n-back task and long term memory performance (recall of emotional and neutral pictures of the International Affective Picture System. Endotoxin administration caused a profound transient physiological response with dose-related elevations in body temperature and heart rate, increases in plasma interleukin (IL-6, IL-10, tumor necrosis factor (TNF-α and IL-1 receptor antagonist (IL-1ra, salivary and plasma cortisol, and plasma norepinephrine. These changes were accompanied by dose-related decreased mood and increased anxiety levels. LPS administration did not affect accuracy in working memory performance but improved reaction time in the high-dose LPS condition compared to the control conditon. In contrast, long-term memory performance was impaired selectively for emotional stimuli after administration of the lower but not of the higher dose of LPS. These data suggest the existence of at least two counter-acting mechanisms, one promoting and one inhibiting cognitive performance during acute systemic inflammation.

  13. Relation between dose of bendrofluazide, antihypertensive effect, and adverse biochemical effects

    DEFF Research Database (Denmark)

    Carlsen, J E; Køber, L; Torp-Pedersen, C

    1990-01-01

    OBJECTIVE--To determine the relevant dose of bendrofluazide for treating mild to moderate hypertension. DESIGN--Double blind parallel group trial of patients who were given placebo for six weeks and then randomly allocated to various doses of bendrofluazide (1.25, 2.5, 5, or 10 mg daily) or place...... of bendrofluazide to treat mild to moderate hypertension is 1.25-2.5 mg a day. Higher doses caused more pronounced adverse biochemical effects including adverse lipid effects. Previous trials with bendrofluazide have used too high doses....... relations between dose and effect were shown for potassium, urate, glucose, total cholesterol, and apolipoprotein B concentrations. The 1.25 mg dose increased only urate concentrations, whereas the 10 mg dose affected all the above biochemical variables. CONCLUSION--The relevant range of doses...

  14. Analysis of offsite dose calculation methodology for a nuclear power reactor

    International Nuclear Information System (INIS)

    Moser, D.M.

    1995-01-01

    This technical study reviews the methodology for calculating offsite dose estimates as described in the offsite dose calculation manual (ODCM) for Pennsylvania Power and Light - Susquehanna Steam Electric Station (SSES). An evaluation of the SSES ODCM dose assessment methodology indicates that it conforms with methodology accepted by the US Nuclear Regulatory Commission (NRC). Using 1993 SSES effluent data, dose estimates are calculated according to SSES ODCM methodology and compared to the dose estimates calculated according to SSES ODCM and the computer model used to produce the reported 1993 dose estimates. The 1993 SSES dose estimates are based on the axioms of Publication 2 of the International Commission of Radiological Protection (ICRP). SSES Dose estimates based on the axioms of ICRP Publication 26 and 30 reveal the total body estimates to be the most affected

  15. Dysphagia disorders in patients with cancer of the oropharynx are significantly affected by the radiation therapy dose to the superior and middle constrictor muscle: A dose-effect relationship

    International Nuclear Information System (INIS)

    Levendag, Peter C.; Teguh, David N.; Voet, Peter; Est, Henri van der; Noever, Inge; Kruijf, Wilhelmus J.M. de; Kolkman-Deurloo, Inger-Karine; Prevost, Jean-Briac; Poll, Johan; Schmitz, Paul I.M.; Heijmen, Ben J.

    2007-01-01

    Purpose/Objective: To assess the relationship between the radiation therapy (RT) dose received by the muscular components of the swallowing (sw) apparatus and - dysphagia related - quality of life (QoL) in oropharyngeal cancer. Materials/Methods: Between 2000 and 2005, 81 patients with SCC of the oropharynx were treated by 3DCRT or IMRT, with or without concomitant chemotherapy (CHT); 43 out of these 81 patients were boosted by brachytherapy (BT). Charts of 81 patients were reviewed with regard to late dysphagia complaints; 23% experienced severe dysphagia. Seventeen patients expired. Fifty-six out of 64 (88%) responded to quality of life (QoL) questionnaires; that is, the Performance Status Scales of List, EORTC H and N35, and the M.D. Anderson Dysphagia Inventory. The superior (scm), middle (mcm), and inferior constrictor muscle (icm), the cricopharyngeus muscle and the inlet of the esophagus, are considered of paramount importance for swallowing. The mean dose was calculated in the muscular structures. Univariate analysis and multivariate analysis were performed using the proportional odds model. Results: Mean follow-up was 18 months (range 2-34) for IMRT, and 46 months for 3DCRT (range 2-72). At 3-years, a LRC of 84%, DFS of 78% and OS of 77% were observed. A significant correlation was observed between the mean dose in the scm and mcm, and severe dysphagia complaints (univariate analysis). A steep dose-effect relationship, with an increase of the probability of dysphagia of 19% with every additional 10 Gy, was established. In the multivariate analysis, BT (dose) was the only significant factor. Conclusion: A dose-effect relationship between dose and swallowing complaints was observed. One way to improve the QoL is to constrain the dose to be received by the swallowing muscles

  16. An efficient dose-compensation method for proximity effect correction

    International Nuclear Information System (INIS)

    Wang Ying; Han Weihua; Yang Xiang; Zhang Yang; Yang Fuhua; Zhang Renping

    2010-01-01

    A novel simple dose-compensation method is developed for proximity effect correction in electron-beam lithography. The sizes of exposed patterns depend on dose factors while other exposure parameters (including accelerate voltage, resist thickness, exposing step size, substrate material, and so on) remain constant. This method is based on two reasonable assumptions in the evaluation of the compensated dose factor: one is that the relation between dose factors and circle-diameters is linear in the range under consideration; the other is that the compensated dose factor is only affected by the nearest neighbors for simplicity. Four-layer-hexagon photonic crystal structures were fabricated as test patterns to demonstrate this method. Compared to the uncorrected structures, the homogeneity of the corrected hole-size in photonic crystal structures was clearly improved. (semiconductor technology)

  17. A review of in vitro dose-effect relationships

    International Nuclear Information System (INIS)

    Dolphin, G.W.

    1978-01-01

    One of the principal reasons for investigating the relationship between absorbed dose and the number of chromosome aberrations per cell in lymphocytes taken from samples of human peripheral blood is to obtain a calibration curve for biological dosimetry. Factors affecting the radiation-induced aberration yield in vitro of T lymphocytes are reviewed under the following heads: temperature, oxygen effect, inter-mitotic death, mitotic delay, dose rate background of aberrations in normal humans, mathematical representation. (U.K.)

  18. Radiation doses to Finns

    International Nuclear Information System (INIS)

    Rantalainen, L.

    1996-01-01

    The estimated annual radiation doses to Finns have been reduced in the recent years without any change in the actual radiation environment. This is because the radiation types have been changed. The risk factors will probably be changed again in the future, because recent studies show discrepancies in the neutron dosimetry concerning the city of Hiroshima. Neutron dosimetry discrepancy has been found between the predicted and estimated neutron radiation. The prediction of neutron radiation is calculated by Monte Carlo simulations, which have also been used when designing recommendations for the limits of radiation doses (ICRP60). Estimation of the neutron radiation is made on the basis of measured neutron activation of materials in the city. The estimated neutron dose beyond 1 km is two to ten, or more, times as high as the predicted dose. This discrepancy is important, because the most relevant distances with respect to radiation risk evaluation are between 1 and 2 km. Because of this discrepancy, the present radiation risk factors for gamma and neutron radiation, which rely on the Monte Carlo calculations, are false, too. The recommendations of ICRP60 have been adopted in a few countries, including Finland, and they affect the planned common limits of the EU. It is questionable whether happiness is increased by adopting false limits, even if they are common. (orig.) (2 figs., 1 tab.)

  19. Dose assessment for decontamination in Goiania

    International Nuclear Information System (INIS)

    Amaral, E.C.S.

    2000-01-01

    Shortly after the accident at Goiania, the need arose to set derived intervention levels for the various exposure pathways to guide and optimise clean up measures. For the members of the critical group an intervention level of 5 mSv for the total effective dose in the first year after the accident was chosen, which then was subdivided into values of 1 mSv due to the contribution of external irradiation indoors, 3 mSv from external irradiation while being outdoors, and 1 mSv due to incorporation of resuspended particles and ingestion of locally produced food. The clean up indoors could be directed such that a pre-described ambient dose rate was no longer exceeded. These exposure levels and effective doses to the critical groups predicted in 1988 are compared to actual measurements made in 1988 to 1993 in a local house near one primary contamination foci, and best estimate. It can be shown that the actual doses received by members of the public living in the affected areas were significantly lower. The various reasons for this overprediction will be discussed. (author)

  20. Radiation dose reduction in a neonatal intensive care unit in computed radiography

    International Nuclear Information System (INIS)

    Frayre, A.S.; Torres, P.; Gaona, E.; Rivera, T.; Franco, J.; Molina, N.

    2012-01-01

    The purpose of this study was to evaluate the dose received by chest x-rays in neonatal care with thermoluminescent dosimetry and to determine the level of exposure where the quantum noise level does not affect the diagnostic image quality in order to reduce the dose to neonates. In pediatric radiology, especially the prematurely born children are highly sensitive to the radiation because of the highly mitotic state of their cells; in general, the sensitivity of a tissue to radiation is directly proportional to its rate of proliferation. The sample consisted of 208 neonatal chest x-rays of 12 neonates admitted and treated in a Neonatal Intensive Care Unit (NICU). All the neonates were preterm in the range of 28–34 weeks, with a mean of 30.8 weeks. Entrance Surface Doses (ESD) values for chest x-rays are higher than the DRL of 50 μGy proposed by the National Radiological Protection Board (NRPB). In order to reduce the dose to neonates, the optimum image quality was achieved by determining the level of ESD where level noise does not affect the diagnostic image quality. The optimum ESD was estimated for additional 20 chest x-rays increasing kVp and reducing mAs until quantum noise affects image quality. - Highlights: ► Entrance surface doses (ESD) in neonates were measured. ► Doses measured in neonates examinations were higher than those reported by literature. ► Reference levels in neonatal studies are required. ► Radiation protection optimization was proposed.

  1. He-Ne laser irradiation affects proliferation of cultured rat Schwann cells in a dose-dependent manner

    International Nuclear Information System (INIS)

    Breugel, H.H.F.I. van; Bar, P.R.

    1993-01-01

    Schwann cell proliferation is considered an essential part of Wallerian degeneration after nerve damage. Laminin, an important component of the extracellular matrix and produced by Schwann cells, provides a preferred substrate for outgrowing axons. To study whether low energy (He-Ne) laser irradiation may exert a positive effect on nerve regeneration through an effect on Schwann cells, its effect was evaluated in vitro. Schwann cells were isolated from sciatic nerves of 4-5-day old Wistar rats and cultures on 96-multiwell plates. The cells were irradiated by a He-Ne laser beam. At three consecutive days, starting either at day 5 or day 8, cells were irradiated each day for 0.5, 1, 2, 5 or 10 min. Both cell number and laminin production were determined for each irradiation condition within one experiment. Schwann cells that were irradiated from day 8 on were hardly affected by laser irradiation. However, the proliferation of cells that were irradiated starting on day 5 was significantly increased after 1, 2 and 5 min of daily irradiation, compared to non-irradiated control cultures. The lamin production per cell of these Schwann cells was not significantly altered. From these results we conclude that He-Ne laser irradiation can modulate proliferation of rat Schwann cells in vitro in a dose-dependent manner. (Author)

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

    Science.gov (United States)

    Duong, Phuong-Anh; Little, Brent P

    2014-08-01

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

  3. Dose-rate effects for apoptosis and micronucleus formation in gamma-irradiated human lymphocytes

    International Nuclear Information System (INIS)

    Boreham, D.R.; Dolling, J.-A.; Maves, S.R.; Siwarungsun, N.; Mitchel, R.E.J.

    2000-01-01

    We have compared dose-rate effects for γ-radiation-induced apoptosis and micronucleus formation in human lymphocytes. Long-term assessment of individual radiation-induced apoptosis showed little intraindividual variation but significant interindividual variation. The effectiveness of radiation exposure to cause apoptosis or micronucleus formation was reduced by low-dose-rate exposures, but the reduction was apparent at different dose rates for these two end points. Micronucleus formation showed a dose-rate effect when the dose rate was lowered to 0.29 cGy/min, but there was no accompanying cell cycle delay. A further increase in the dose-rate effect was seen at 0.15 cGy/min, but was now accompanied by cell cycle delay. There was no dose-rate effect for the induction of apoptosis until the dose rate was reduced to 0.15 cGy/min, indicating that the mechanisms or signals for processing radiation-induced lesions for these two end points must be different at least in part. There appear to be two mechanisms that contribute to the dose-rate effect for micronucleus formation. One of these does not affect binucleate cell frequency and occurs at dose rates higher than that required to produce a dose-rate effect for apoptosis, and one affects binucleate cell frequency, induced only at the very low dose rate which coincidentally produces a dose-rate effect for apoptosis. Since the dose rate at which cells showed reduced apoptosis as well as a further reduction in micronucleus formation was very low, we conclude that the processing of the radiation-induced lesions that induce apoptosis, and some micronuclei, is very slow in quiescent and PHA-stimulated lymphocytes, respectively. (author)

  4. Dose-rate effects for apoptosis and micronucleus formation in gamma-irradiated human lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Boreham, D.R.; Dolling, J.-A.; Maves, S.R. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Siwarungsun, N. [Chulalongkorn Univ., Bangkok (Thailand); Mitchel, R.E.J. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2000-07-01

    We have compared dose-rate effects for {gamma}-radiation-induced apoptosis and micronucleus formation in human lymphocytes. Long-term assessment of individual radiation-induced apoptosis showed little intraindividual variation but significant interindividual variation. The effectiveness of radiation exposure to cause apoptosis or micronucleus formation was reduced by low-dose-rate exposures, but the reduction was apparent at different dose rates for these two end points. Micronucleus formation showed a dose-rate effect when the dose rate was lowered to 0.29 cGy/min, but there was no accompanying cell cycle delay. A further increase in the dose-rate effect was seen at 0.15 cGy/min, but was now accompanied by cell cycle delay. There was no dose-rate effect for the induction of apoptosis until the dose rate was reduced to 0.15 cGy/min, indicating that the mechanisms or signals for processing radiation-induced lesions for these two end points must be different at least in part. There appear to be two mechanisms that contribute to the dose-rate effect for micronucleus formation. One of these does not affect binucleate cell frequency and occurs at dose rates higher than that required to produce a dose-rate effect for apoptosis, and one affects binucleate cell frequency, induced only at the very low dose rate which coincidentally produces a dose-rate effect for apoptosis. Since the dose rate at which cells showed reduced apoptosis as well as a further reduction in micronucleus formation was very low, we conclude that the processing of the radiation-induced lesions that induce apoptosis, and some micronuclei, is very slow in quiescent and PHA-stimulated lymphocytes, respectively. (author)

  5. The embryogenesis of dose assessment at Hanford

    International Nuclear Information System (INIS)

    Foster, R.F.

    1990-01-01

    Several significant events occurred between 1955 and 1960 that resulted in major changes in environmental monitoring at Hanford and in the initiation of comprehensive dose assessments. These included: (1) specification of dose limits for nonoccupational exposure (including internal emitters); (2) a national and international awakening to the need for managing the disposal of radioactive wastes; (3) identification of the most important radionuclides and their sources of exposure; (4) data that quantified the transfer coefficients of nuclides along environmental pathways; and (5) development of greatly improved radiation detection instrumentation. In response to a growing need, the Hanford Laboratories formed the Environmental Studies and Evaluation component. This group revamped the monitoring and sampling programs so that analytical results contributed directly to dose estimation. Special studies were conducted to ascertain local dietary and recreational habits that affected dose calculations and to calibrate the models. These studies involved extensive contact with the public and governmental agencies, which elicited a positive reaction

  6. Establishing the irradiation dose for paper decontamination

    International Nuclear Information System (INIS)

    Moise, Ioan Valentin; Virgolici, Marian; Negut, Constantin Daniel; Manea, Mihaela; Alexandru, Mioara; Trandafir, Laura; Zorila, Florina Lucica; Talasman, Catalina Mihaela; Manea, Daniela; Nisipeanu, Steluta; Haiducu, Maria; Balan, Zamfir

    2012-01-01

    Museums, libraries and archives are preserving documents that are slowly degrading due to the inherent ageing of the cellulose substrate or to the technological errors of the past (acid paper, iron gall ink). Beside this, large quantities of paper are rapidly damaged by biological attacks following natural disasters and improper storage conditions. The treatment of paper documents with ionizing radiation can be used for mass decontamination of cultural heritage items but conservators and restaurators are still reserved because of the radiation induced degradation. We conducted a study for establishing the dose needed for the effective treatment of paper documents, taking into account the biological burden and the irradiation effects on paper structure. We used physical testing specific to paper industry and less destructive analytical methods (thermal analysis). Our results show that an effective treatment can be performed with doses lower than 10 kGy. Old paper appears to be less affected by gamma radiation than recent paper but the sampling is highly affected by the non-uniform degree of the initial degradation status. The extent of testing for degradation and the magnitude of acceptable degradation should take into account the biological threat and the expected life time of the paper documents. - RESEARCH HIGHLIGHTS: ► For doses <15 kGy, the measurement uncertainty of mechanical properties is higher than the radiation induced degradation. ► The statistics of measuring induced degradation may be improved by testing both mechanical properties and thermal decomposition of paper. ►Because of the large variability of paper samples, testing to only one irradiation dose has no or reduced relevance. ►It was choused for the irradiation of paper items from archives and collections a dose range of 5–7 kGy.

  7. Characteristics of repair following very low doses

    International Nuclear Information System (INIS)

    Braby, L.A.; Metting, N.F.; Nelson, J.M.

    1987-01-01

    The effects of ionizing radiation on living systems being with the physical processes of energy deposition and develop through many stages of chemical reaction and biological response. The modeling effort attempts to organize the available data and theories of all of these stages into self-consistent models that can be compared and tested. In some cases, important differences among models result in only small differences in cell survival within the ranges of dose and dose rate that are normally investigated. To overcome this limitation, new ways of irradiating cells at extremes of dose rate, or ways of evaluating the effects of very small doses, are developed. Mathematical modeling and cellular studies complement each other. It has recently been found that some mechanisms are not adequate to account for the interaction of dose and repair time as they affect the reproductive survival of plateau-phase Chinese hamster ovary (CHO) cells. Repair of radiation-induced cellular damage plays a central role in the survival of cells exposed to doses of 1 Gy or more. This repair is responsible for the dose rate, split-dose and delayed plating effect and can be evaluated. Because split-dose and dose-rate experiments involve repair during irradiation and delayed plating experiments involve repair after irradiation is completed, it was originally thought that different repair processes were involved. It is now clear that this is not necessarily the case. Appropriately designed models can account for observed effects at conventional doses (1 Gy or more) whether they assume all damage is lethal unless repaired or some damage is innocuous unless it interacts with additional damage. The fact that the survival following a plating delay is always less than the survival following immediate plating at low doses indicates that the damage produced is probably not potentially lethal

  8. Factors affecting quality for beta dose rate measurements using ISO 6980 series I reference sources

    Energy Technology Data Exchange (ETDEWEB)

    Burns, R.E. Jr.; O`Brien, J.M. Jr. [Atlan-Tech, Rosewll, GA (United States)

    1993-12-31

    Atlan-Tech, Inc. has performed several calibrations of ISO 6980 Series 1 reference beta sources over the past two to three years. There were many problems encountered in attempting to compare the results of these calibrations with those from other laboratories, indicating the need for more standardization in the methodology employed for the measurement of the absorbed dose rate from ISO 6980 Series 1 reference beta sources. This document describes some of the problems encountered in attempting to intercompare results of beta dose-rate measurements. It proposes some solutions in an attempt to open a dialogue among facilities using reference beta standards for the purpose of promoting better measurement quality assurance through data intercomparison.

  9. Factors affecting quality for beta dose rate measurements using ISO 6980 series I reference sources

    International Nuclear Information System (INIS)

    Burns, R.E. Jr.; O'Brien, J.M. Jr.

    1993-01-01

    Atlan-Tech, Inc. has performed several calibrations of ISO 6980 Series 1 reference beta sources over the past two to three years. There were many problems encountered in attempting to compare the results of these calibrations with those from other laboratories, indicating the need for more standardization in the methodology employed for the measurement of the absorbed dose rate from ISO 6980 Series 1 reference beta sources. This document describes some of the problems encountered in attempting to intercompare results of beta dose-rate measurements. It proposes some solutions in an attempt to open a dialogue among facilities using reference beta standards for the purpose of promoting better measurement quality assurance through data intercomparison

  10. Early exposure to a low dose of bisphenol A affects socio-sexual behavior of juvenile female rats.

    Science.gov (United States)

    Porrini, Stefania; Belloni, Virginia; Della Seta, Daniele; Farabollini, Francesca; Giannelli, Giuletta; Dessì-Fulgheri, Francesco

    2005-04-15

    Play behavior is affected by alteration of the hormonal environment during development. In fact, congenital adrenal hyperplasia or early administration of diethylstilbestrol are able to modify female play behavior in mammals. In this research, play behavior of female rats was used to explore the effects of perinatal exposure to low, environmentally relevant dose of bisphenol A (BPA), a xenoestrogen widely diffused in the environment. We used 18 females born to mothers exposed to 40 microg/kg/day BPA during pregnancy and lactation, and 18 control females. The subjects were observed in a heterosexual social situation from 35 to 55 days of age. Six main behaviors were identified by principal component analysis (PCA): exploration, defensive behavior to males, play behavior with males, play behavior with females, low-intensity mating behavior, social grooming. Early administration of BPA was responsible for a significant increase of exploration (including social investigation) (pbehavior, but is able however to defeminize some aspects of female behavior. This result is compatible with the estrogenic properties of BPA, and suggests caution in the use of a chemical that, in the range of human exposure, is able to influence the development of the brain during a critical period, resulting in long-term effects on behavior.

  11. The Hanford Environmental Dose Reconstruction Project: Overview

    International Nuclear Information System (INIS)

    Haerer, H.A.; Freshley, M.D.; Gilbert, R.O.; Morgan, L.G.; Napier, B.A.; Rhoads, R.E.; Woodruff, R.K.

    1990-01-01

    In 1988, researchers began a multiyear effort to estimate radiation doses that people could have received since 1944 at the U.S. Department of Energy's Hanford Site. The study was prompted by increasing concern about potential health effects to the public from more than 40 yr of nuclear activities. We will provide an overview of the Hanford Environmental Dose Reconstruction Project and its technical approach. The work has required development of new methods and tools for dealing with unique technical and communication challenges. Scientists are using a probabilistic, rather than the more typical deterministic, approach to generate dose distributions rather than single-point estimates. Uncertainties in input parameters are reflected in dose results. Sensitivity analyses are used to optimize project resources and define the project's scope. An independent technical steering panel directs and approves the work in a public forum. Dose estimates are based on review and analysis of historical data related to operations, effluents, and monitoring; determination of important radionuclides; and reconstruction of source terms, environmental conditions that affected transport, concentrations in environmental media, and human elements, such as population distribution, agricultural practices, food consumption patterns, and lifestyles. A companion paper in this volume, The Hanford Environmental Dose Reconstruction Project: Technical Approach, describes the computational framework for the work

  12. Ultrastructural study of the effect of cyclophosphamide on the growth area of incisor teeth of DBA/2 and C57BL/6 mice.

    Science.gov (United States)

    Anton, E

    1996-04-01

    The effect of a single dose of 300 mg/kg of cyclophosphamide (CY) on the ultrastructure of the basal area of lower incisor teeth was investigated in two strains of mice (DBA/2 and C57BL/6) which are very differently affected by the delayed toxicity of CY. As in the rat, CY produced necrosis in the primitive mesenchymal cells and preodontoblasts of the pulp. Moreover, important changes were noticed in the associated layers of the enamel organ (presumptive stratum intermedium cells and stellate reticulum); thus, most of the cells displayed degenerative changes including extensive vacuolization, cytoplasm sequestration and variable nuclear alterations ranging from relative integrity to complete disorganization. In contrast, non-dividing columnar odontoblasts and ameloblasts were not affected by the drug. The alterations appeared as early as 21 hours after CY and progressed in the following 2 and 3 days. Normality of the formative tooth end was regained 7 days after CY. These results indicate that in addition to the effect on the pulp, CY produces severe cytopathological changes in the cells of the stratum intermedium and stellate reticulum of the enamel organ. The different sensitivity of DBA/2 and C57BL/6 mice to the delayed toxicity of CY does not seem to be related to its effect on odontogenesis since both strains showed the same response to CY in this respect.

  13. Dose rates of beach sands along the Enshu-nada coast

    International Nuclear Information System (INIS)

    Minato, Susumu; Shimo, Michikuni

    2014-01-01

    In order to understand the mechanism of beach-to-beach variations in dose rates, measurements at 35 sand beaches were carried out along the Enshu-nada coast (a total of 140km). The sand samples were collected at 10 beaches to obtain the concentrations of potassium, uranium and thorium by means of Ge(Li) spectroscopy. Factors affecting the variation in dose rates were discussed, incorporating these data with data of coastal sea-bottom sediments taken by the Geological Survey of Japan. Two-dimensional measurements were performed at 50 locations each in two beaches near the Tenryu river mouth to know within-beach variations in detail. Contour maps of the data revealed a considerable regularity. It was found from simple analyses of the data collected in this work that the dose rate levels at beaches are affected by the distance from the river mouth, erosion or sedimentation of beach, and depth distribution of seawater. (author)

  14. Stage-specific effects of FGF2 on the differentiation of dental pulp cells

    Science.gov (United States)

    Sagomonyants, Karen; Mina, Mina

    2015-01-01

    Dentinogenesis is a complex and multistep process, which is regulated by various growth factors, including members of the Fibroblast Growth Factor (FGF) family. Both positive and negative effects of FGFs on dentinogenesis have been reported but the underlying mechanisms of these conflicting results are still unclear. To gain better insight into the role of FGF2 in dentinogenesis, we used dental pulp cells from various transgenic mice, in which fluorescent protein expression identifies cells at different stages of odontoblast differentiation. Our results showed that continuous exposure of pulp cells to FGF2 inhibited mineralization and revealed both stimulatory and inhibitory effects of FGF2 on expression of markers of dentinogenesis and various transgenes. During the proliferation phase of in vitro growth FGF2 increased expression of markers of dentinogenesis and the percentages of DMP1-GFP+ functional odontoblasts and DSPP-Cerulean+ odontoblasts. Additional exposure to FGF2 during the differentiation/mineralization phase of in vitro growth decreased the extent of mineralization, expression of markers of dentinogenesis, and expression of DMP1-GFP and DSPP-Cerulean transgenes. Recovery experiments showed that the inhibitory effects of FGF2 on dentinogenesis were related to the blocking of differentiation of cells into mature odontoblasts. These observations together showed stage-specific effects of FGF2 on dentinogenesis by dental pulp cells and provide critical information for the development of improved treatments for vital pulp therapy and dentin regeneration. PMID:25823776

  15. Effects of low doses of gamma rays on yield, yield components, and other characters of two maize varieties

    International Nuclear Information System (INIS)

    Yousif, Z. B.; Jabbo, N. F.; Khalaf, M. Z.; Majid, A. H.; Ali, H. J.

    1994-01-01

    The study was conducted during the fall of 1991 and 1992 at Al-Latyfia Experimental Station to determine the effect of low doses of gamma rays on yield, yield components, and other characters of two maize varieties. Five doses were used in addition to control. A factorial experiment with randomized complete block design in three replications was used in the study. Results revealed that there was significant difference between varieties in plant and ear height in 1992. However, differences between varieties were also significantly affected by most yield component characters. Low doses significantly affected plant height, weight of 500 kernels in 1991, and kernel row number in 1992. Grain yield was affected significantly in 1991 and 1992 by low doses. Results showed that 2.0 krad was the most useful low dose to increase grain yield, whereas there was no significant effect between varieties in grain yield. 7 refs., 6 tabs

  16. Retrospective Dosimetry: Dose Analysis From Tooth Enamel Using Electron Spin Resonance (ESR)

    International Nuclear Information System (INIS)

    Mohd Rodzi Ali; Rahimah Abdul Rahim; Noraisyah Yusof; Syed Asraf Fahlawi Wafa Syed Mohd Ghazi; Juliana Mahamad Napiah; Yahaya Talib; Rehir Dahalan

    2014-01-01

    The radiation dose should be accurately measured in order to relate its effect to the cells. The assessment of dose usually performed using biological dosimetry techniques. However, the reduction of lymphocytes (white blood cells) after the time period results in inaccuracy of dose measurement. An alternative method used is the application of Electron Spin Resonance (ESR) using tooth enamel. In this study, tooth enamels were evaluated and used to measure the individual absorbed dose from the background. The basic tooth features that would affect dose measurement were discussed. The results show this technique is capable and effective for retrospective dose measurement and useful for the study of radiation effect to human. (author)

  17. Analysis of occupational doses in radioactive and nuclear facilities

    International Nuclear Information System (INIS)

    Curti, A.; Gomez P, I.; Pardo, G.; Thomasz, E.

    1996-01-01

    Occupational doses were analyzed in the most important nuclear and radioactive facilities in Argentina, on the period 1988-1994. The areas associated with uranium mining and milling, and medical uses of radiation facilities were excluded from this analysis. The ICRP publication 60 recommendations, adopted in 1990, and enforced in Argentine in 1994, keep the basic criteria of dose limitation system and recommend a substantial reduction in the dose limits. The reduction of the dose limits will affect the individual dose distributions, principally in those installations with occupational doses close to 50 mSv. It were analyzed Occupational doses, principally in the following facilities: Atucha-I and Embalse Nuclear Power Plants, radioisotope production plants, research reactors and radioactive waste management plants. The highest doses were identified in each facility, as well as the task associated with them. Trends in the individual dose distribution and collective and average doses were analyzed. It is concluded, that no relevant difficulties should appear in accomplishing with the basic standards for radiological safety, except for the Atucha-I Nuclear Power Plant. In this NPP a significant effort for the optimization of radiological safety procedures in order to diminish the occupational doses, and a change of the fuel channels by new ones free of cobalt are being carried out. (authors). 4 refs., 3 figs., 3 tabs

  18. Dose rate constants for new dose quantities

    International Nuclear Information System (INIS)

    Tschurlovits, M.; Daverda, G.; Leitner, A.

    1992-01-01

    Conceptual changes and new quantities made is necessary to reassess dose rate quantities. Calculations of the dose rate constant were done for air kerma, ambient dose equivalent and directional dose equivalent. The number of radionuclides is more than 200. The threshold energy is selected as 20 keV for the dose equivalent constants. The dose rate constant for the photon equivalent dose as used mainly in German speaking countries as a temporary quantity is also included. (Author)

  19. Simulation of lung cancer treatment with equivalent dose calculation and analysis of the dose distribution profile

    International Nuclear Information System (INIS)

    Thalhofer, J. L.; Marques L, J.; Da Silva, A. X.; Dos Reis J, J. P.; Da Silva J, W. F. R.; Arruda C, S. C.; Monteiro de S, E.; Santos B, D. V.

    2017-10-01

    Actually, lung cancer is one of the most lethal types, due to the disease in the majority of the cases asymptomatic in the early stages, being the detection of the pathology in advanced stage, with tumor considerable volume. Dosimetry analysis of healthy organs under real conditions is not feasible. Therefore, computational simulations are used to auxiliary in dose verification in organs of patients submitted to radiotherapy. The goal of this study is to calculate the equivalent dose, due to photons, in surrounding in healthy organs of a patient submitted to radiotherapy for lung cancer, through computational modeling. The simulation was performed using the MCNPX code (Version, 2006], Rex and Regina phantom [ICRP 110, 2008], radiotherapy room, Siemens Oncor Expression accelerator operating at 6 MV and treatment protocol adopted at the Inca (National Cancer Institute, Brazil). The results obtained, considering the dose due to photons for both phantom indicate that organs located inside the thoracic cavity received higher dose, being the bronchi, heart and esophagus more affected, due to the anatomical positioning. Clinical data describe the development of bronchiolitis, esophagitis, and cardiomyopathies with decreased cardiopulmonary function as one of the major effects of lung cancer treatment. In the Regina phantom, the second largest dose was in the region of the breasts with 615,73 mSv / Gy, while in the Rex 514,06 mSv / Gy, event related to the difference of anatomical structure of the organ. Through the t mesh command, a qualitative analysis was performed between the dose deposition profile of the planning system and the simulated treatment, with a similar profile of the dose distribution being verified along the patients body. (Author)

  20. Single Dose Versus 3 Doses of Intramuscular Benzathine Penicillin for Early Syphilis in HIV: A Randomized Clinical Trial.

    Science.gov (United States)

    Andrade, Roberto; Rodriguez-Barradas, Maria C; Yasukawa, Kosuke; Villarreal, Erick; Ross, Michael; Serpa, Jose A

    2017-03-15

    Patients coinfected with syphilis and human immunodeficiency virus (HIV) may have a slower decrease in rapid plasma reagin (RPR) titers. Currently a single dose of 2.4 million units of intramuscular benzathine penicillin G (BPG) is recommended for the treatment of early syphilis. Some observational studies have suggested that this regimen may lead to high failure rates in coinfected patients. We conducted an open-label randomized clinical trial to compare the efficacy of single-dose and 3-dose regimens of BPG for the treatment of early syphilis in HIV-infected individuals. RPR titers were monitored every 3 months. Treatment success was defined as a decrease in RPR titers of ≥2 dilutions (4-fold) during a 12-month follow-up period. Sixty-four patients were included. In the intention-to-treat analysis, treatment success rates were 80% (28 of 35 subjects) and 93% (27 of 29 subjects) in the single-dose and 3-dose regimens, respectively (absolute difference, 13% [95% confidence interval {CI}, -5% to 30%; P = .17). In the per-protocol analysis, success rates were 93% (27 of 29) and 100% in the single-dose and 3-dose regimens, respectively (absolute difference, 7% [95% CI, -7% to 22%]; P = .49). CD4 T-cell count, RPR titer and syphilis stage did not affect treatment results. When compared with a single dose of BPG, a 3-dose regimen did not improve syphilis serological outcomes. Our results support the Centers for Disease Control and Prevention recommendation of a single dose of BPG in HIV-infected patients with early syphilis. NCT02611765. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  1. Analysis of factors affecting the outcome of Graves disease patients treated with two regimens of fixed Iodine-131 doses (10 mCi and 15 mCi)

    International Nuclear Information System (INIS)

    Machado, Ana C.B.; Santos, Roberto B.; Chaves, Fatima R.; Romaldini, Joao H.; Ward, Laura S.

    2005-01-01

    Full text: The use of fixed doses of radioiodine ( 131 I) simplifies the approach to treatment for Graves' disease (GD) patients with potential cost savings. In order to evaluate factors that may affect the outcome of 2 different regimens of 131 I, we prospectively examined 128 patients with overt thyrotoxicosis from GD, as confirmed by suppressed serum TSH, presence of TRAb, increased serum T 3 and FT 4 values. Group 1 comprised 76 patients who received a fixed dose of 10 mCi and Group 2=52 patients who received a fixed dose of 15 mCi. 36 patients did not use any antithyroid drugs and 92 patients used methimazole that was withdrawn at least 5 days before radioiodine administration. Antithyroid drugs treatment was restarted at least 7 days following 131 I therapy when needed. Baseline serum TSH and FT 4 levels were measured at 3, 6, 9 and 12 months after treatment. The groups were similar concerning age, gender, smoke, eye disease, goiter size, serum T 3 , FT 4 , TRAb, anti-Tg and anti-TPO levels as well as 24-hour 131 I or Tec-uptake values and thyroid scan. Clinical outcome was evaluated at the end of 1-year follow-up and cure of hyperthyroidism was defined as clinical and laboratory evidence of either euthyroidism or hypothyroidism in the absence of antithyroid drugs. The cure rate obtained was similar in groups 1 and 2: 73.7% and 80.8%, respectively (p=0.35). Hypothyroidism was diagnosed in 56.5% and 71.15% of the patients from groups 1 and 2, respectively (p=0.13). There was no correlation between clinical features, thyroid uptake, antibodies, serum hormones and outcome. However, logistic regression analysis demonstrated that patients with larger thyroids (weight >60 g) that, consequently, received a lower dose of radioiodine in MBq/g, had 2.4 times less chance to cure (95% Cl=1.18-4.96). The use of fixed doses of radioiodine ( 131 I) simplifies the approach to treatment for Graves' disease (GD) patients with potential cost savings. In order to evaluate

  2. Dose measurement, its distribution and individual external dose assessments of inhabitants on high background radiation area in China

    Energy Technology Data Exchange (ETDEWEB)

    Koga, Taeko; Morishima, Hiroshige [Kinki Univ., Atomic Energy Research Institute, Osaka (Japan); Tatsumi, Kusuo [Kinki Univ., Life Science Research Institute, Osaka (Japan); Nakai, Sayaka; Sugahara, Tsutomu [Health Research Foundation, Kyoto (Japan); Yuan Yongling [Labor Hygiene Institute of Hunan Prov. (China); Wei Luxin [Laboratory of Industorial Hygiene, Ministry of Health (China)

    2001-01-01

    As a part of the China-Japan cooperative research on the natural radiation epidemiology, we have carried out a dose-assessment study to evaluate the external to natural radiation in the high background radiation area (HBRA) of Yangjiang in Guangdong province and in the control area (CA) of Enping prefecture since 1991. Because of the difficulties in measuring the individual doses of all inhabitants directly by the personal dosimeters, an indirect method was applied to estimate the exposed dose rates from the environmental radiation dose rates measured by survey meters and the occupancy factors of each hamlet. An individual radiation dose roughly correlates with the environmental radiation dose and the life style of the inhabitant. We have analyzed the environmental radiation doses in the hamlets and the variation of the occupancy factors to obtain the parameters of dose estimation on the inhabitants in selected hamlets; Madi and the several hamlets of the different level doses in HBRA and Hampizai hamlet in CA. With these parameters, we made estimations of individual dose rates and compared them with those obtained from the direct measurement using dosimeters carried by selected individuals. The results obtained are as follows: (1) The environmental radiation dose rates are influenced by the natural radioactive nuclide concentrations in building materials, the age of the building and the arrangement of the houses in a hamlet. There existed a fairly large and heterogeneous distribution of indoor and outdoor environmental radiation. The indoor radiation dose rates were due to the exposure from the natural radioactive nuclides in the building materials and they were about twice higher than the outdoor radiation dose rates. This difference was not observed in CA. (2) The occupancy factor was affected by the age of individuals and the seasons of a year. Indoor occupancy factors were higher for infants and aged individuals than for other age groups. This lead to higher

  3. Dose measurement, its distribution and individual external dose assessments of inhabitants on high background radiation area in China

    International Nuclear Information System (INIS)

    Koga, Taeko; Morishima, Hiroshige; Tatsumi, Kusuo; Nakai, Sayaka; Sugahara, Tsutomu; Yuan Yongling; Wei Luxin

    2001-01-01

    As a part of the China-Japan cooperative research on the natural radiation epidemiology, we have carried out a dose-assessment study to evaluate the external to natural radiation in the high background radiation area (HBRA) of Yangjiang in Guangdong province and in the control area (CA) of Enping prefecture since 1991. Because of the difficulties in measuring the individual doses of all inhabitants directly by the personal dosimeters, an indirect method was applied to estimate the exposed dose rates from the environmental radiation dose rates measured by survey meters and the occupancy factors of each hamlet. An individual radiation dose roughly correlates with the environmental radiation dose and the life style of the inhabitant. We have analyzed the environmental radiation doses in the hamlets and the variation of the occupancy factors to obtain the parameters of dose estimation on the inhabitants in selected hamlets; Madi and the several hamlets of the different level doses in HBRA and Hampizai hamlet in CA. With these parameters, we made estimations of individual dose rates and compared them with those obtained from the direct measurement using dosimeters carried by selected individuals. The results obtained are as follows: 1) The environmental radiation dose rates are influenced by the natural radioactive nuclide concentrations in building materials, the age of the building and the arrangement of the houses in a hamlet. There existed a fairly large and heterogeneous distribution of indoor and outdoor environmental radiation. The indoor radiation dose rates were due to the exposure from the natural radioactive nuclides in the building materials and they were about twice higher than the outdoor radiation dose rates. This difference was not observed in CA. 2) The occupancy factor was affected by the age of individuals and the seasons of a year. Indoor occupancy factors were higher for infants and aged individuals than for other age groups. This lead to higher

  4. [Evaluation of Organ Dose Estimation from Indices of CT Dose Using Dose Index Registry].

    Science.gov (United States)

    Iriuchijima, Akiko; Fukushima, Yasuhiro; Ogura, Akio

    Direct measurement of each patient organ dose from computed tomography (CT) is not possible. Most methods to estimate patient organ dose is using Monte Carlo simulation with dedicated software. However, dedicated software is too expensive for small scale hospitals. Not every hospital can estimate organ dose with dedicated software. The purpose of this study was to evaluate the simple method of organ dose estimation using some common indices of CT dose. The Monte Carlo simulation software Radimetrics (Bayer) was used for calculating organ dose and analysis relationship between indices of CT dose and organ dose. Multidetector CT scanners were compared with those from two manufactures (LightSpeed VCT, GE Healthcare; SOMATOM Definition Flash, Siemens Healthcare). Using stored patient data from Radimetrics, the relationships between indices of CT dose and organ dose were indicated as each formula for estimating organ dose. The accuracy of estimation method of organ dose was compared with the results of Monte Carlo simulation using the Bland-Altman plots. In the results, SSDE was the feasible index for estimation organ dose in almost organs because it reflected each patient size. The differences of organ dose between estimation and simulation were within 23%. In conclusion, our estimation method of organ dose using indices of CT dose is convenient for clinical with accuracy.

  5. SU-F-J-133: Adaptive Radiation Therapy with a Four-Dimensional Dose Calculation Algorithm That Optimizes Dose Distribution Considering Breathing Motion

    Energy Technology Data Exchange (ETDEWEB)

    Ali, I; Algan, O; Ahmad, S [University of Oklahoma Health Sciences, Oklahoma City, OK (United States); Alsbou, N [University of Central Oklahoma, Edmond, OK (United States)

    2016-06-15

    Purpose: To model patient motion and produce four-dimensional (4D) optimized dose distributions that consider motion-artifacts in the dose calculation during the treatment planning process. Methods: An algorithm for dose calculation is developed where patient motion is considered in dose calculation at the stage of the treatment planning. First, optimal dose distributions are calculated for the stationary target volume where the dose distributions are optimized considering intensity-modulated radiation therapy (IMRT). Second, a convolution-kernel is produced from the best-fitting curve which matches the motion trajectory of the patient. Third, the motion kernel is deconvolved with the initial dose distribution optimized for the stationary target to produce a dose distribution that is optimized in four-dimensions. This algorithm is tested with measured doses using a mobile phantom that moves with controlled motion patterns. Results: A motion-optimized dose distribution is obtained from the initial dose distribution of the stationary target by deconvolution with the motion-kernel of the mobile target. This motion-optimized dose distribution is equivalent to that optimized for the stationary target using IMRT. The motion-optimized and measured dose distributions are tested with the gamma index with a passing rate of >95% considering 3% dose-difference and 3mm distance-to-agreement. If the dose delivery per beam takes place over several respiratory cycles, then the spread-out of the dose distributions is only dependent on the motion amplitude and not affected by motion frequency and phase. This algorithm is limited to motion amplitudes that are smaller than the length of the target along the direction of motion. Conclusion: An algorithm is developed to optimize dose in 4D. Besides IMRT that provides optimal dose coverage for a stationary target, it extends dose optimization to 4D considering target motion. This algorithm provides alternative to motion management

  6. Optimal initial dose adjustment of warfarin in orthopedic patients.

    Science.gov (United States)

    Lenzini, Petra A; Grice, Gloria R; Milligan, Paul E; Gatchel, Susan K; Deych, Elena; Eby, Charles S; Burnett, R Stephen J; Clohisy, John C; Barrack, Robert L; Gage, Brian F

    2007-11-01

    Warfarin sodium is commonly prescribed for the prophylaxis and treatment of venous thromboembolism. Dosing algorithms have not been widely adopted because they require a fixed initial warfarin dose (eg, 5 mg) and are not tailored to other factors that may affect the international normalized ratio (INR). To develop an algorithm that could predict a therapeutic warfarin dose based on drug interactions, INR response after the initial warfarin doses, and other clinical factors. We used stepwise regression to quantify the relationship between these factors in patients beginning prophylactic warfarin therapy immediately prior to joint replacement. In the derivation cohort (n = 271), we separately modeled the therapeutic dose after 2 and 3 initial doses. We prospectively validated these 2 models in an independent cohort (n = 105). About half of the therapeutic dose variability was predictable after 3 days of therapy: R2 was 53% in the derivation cohort and 42% in the validation cohort. INR response after 3 warfarin doses (INR3) inversely correlated with therapeutic dose (p < 0.001). Intraoperative blood loss transiently, but significantly, elevated the postoperative INR values. Other significant (p < 0.03) predictors were the first and second warfarin doses (+7% and +6%, respectively, per 1 mg), and statin use (-15.0%). The model derived after 2 warfarin doses explained 32% of the variability in therapeutic dose. We developed and validated algorithms that estimate therapeutic warfarin doses based on clinical factors and INR response available after 2-3 days of warfarin therapy. The algorithms are implemented online at www.WarfarinDosing.org.

  7. Work management practices that reduce dose and improve efficiency

    International Nuclear Information System (INIS)

    Miller, D.W.; Hulin, M.

    1998-01-01

    Work management practices at nuclear power plants can dramatically affect the outcome of annual site dose goals and outage costs. This presentation discusses global work management practices that contribute to dose reduction including work philosophy, work selection, work planning, work scheduling, worker training, work implementation and worker feedback. The presentation is based on a two-year international effort (sponsored by NEA/IAEA ISOE) to study effective work practices that reduce dose. Experts in this area believe that effective work selection and planning practices can substantially reduce occupational dose during refueling outages. For example, some plants represented in the expert group complete refueling outages in 12-18 days (Finland) with doses below 0,90 person-Sv. Other plants typically have 50-75 day outages with substantially higher site doses. The fundamental reasons for longer outages and higher occupational doses are examined. Good work management principles that have a proven track record of reducing occupational dose are summarized. Practical methods to reduce work duration and dose are explained. For example, scheduling at nuclear power plants can be improved by not only sequencing jobs on a time line but also including zone and resource-based considerations to avoid zone congestion and manpower delays. An ongoing, global, benchmarking effort is described which provides current duration and dose information for repetitive jobs to participating utilities world-wide. (author)

  8. Estimation of the total absorbed dose by quartz in retrospective conditions

    International Nuclear Information System (INIS)

    Correcher, V.; Delgado, A.

    2003-01-01

    The estimation of the total absorbed dose is of great interest in areas affected by a radiological accident when no conventional dosimetric systems are available. This paper reports about the usual methodology employed in dose reconstruction from the thermoluminescence (TL) properties of natural quartz, extracted from selected ceramic materials (12 bricks) picked up in the Chernobyl area. It has been possible to evaluate doses under 50mGy after more than 11 years later since the radiological accident happened. The main advance of this fact is the reduction of the commonly accepted limit dose estimation more than 20 times employing luminescence methods. (Author) 11 refs

  9. Comparison of proton and photon dose distributions

    International Nuclear Information System (INIS)

    Goitein, Michael

    1995-01-01

    Recently, there has been considerable work, as yet largely theoretical, in developing ways to improve the dose distributions which can be achieved with x-rays. Foremost among these developments are the use of non-coplanar beam directions, the use of intensity-modulated beams, and the implementation of computer-controlled delivery of complex plans using new beam modifiers such as multi-leaf collimators and beam scanners. One way of improving the dose distributions which have been achieved with conventional radiations is to use protons, with their quite different physical characteristics but very similar radiobiological properties as compared with supervoltage x-rays. Some substantial experience has been gained in the use of protons which has confirmed clinically that better results have been obtained as a result of their better dose distributions. Indeed, it is fair to say that the advantages which protons have demonstrated are, in large part, responsible for the renewed interest in improving the dose distributions from all radiation modalities. So much better are the dose distributions which the new techniques, mentioned above, offer that there is the impression that, with their use, photons can deliver dose distributions as good as can be obtained with protons. In this paper, the extent of the possible improvement will be discussed. It will be suggested that the integral dose is relatively little affected by the treatment technique - so that the lower normal tissue doses which the new approaches offer is almost always at the price of delivering dose to a larger volume. Protons can be matched pencil beam for pencil beam with photons - and then almost always deliver substantially less dose outside the target volume. Ultimately, the clinical importance of the differences will have to decided by clinical trial

  10. Estimation and comparison of effective dose (E) in standard chest CT by organ dose measurements and dose-length-product methods and assessment of the influence of CT tube potential (energy dependency) on effective dose in a dual-source CT.

    Science.gov (United States)

    Paul, Jijo; Banckwitz, Rosemarie; Krauss, Bernhard; Vogl, Thomas J; Maentele, Werner; Bauer, Ralf W

    2012-04-01

    To determine effective dose (E) during standard chest CT using an organ dose-based and a dose-length-product-based (DLP) approach for four different scan protocols including high-pitch and dual-energy in a dual-source CT scanner of the second generation. Organ doses were measured with thermo luminescence dosimeters (TLD) in an anthropomorphic male adult phantom. Further, DLP-based dose estimates were performed by using the standard 0.014mSv/mGycm conversion coefficient k. Examinations were performed on a dual-source CT system (Somatom Definition Flash, Siemens). Four scan protocols were investigated: (1) single-source 120kV, (2) single-source 100kV, (3) high-pitch 120kV, and (4) dual-energy with 100/Sn140kV with equivalent CTDIvol and no automated tube current modulation. E was then determined following recommendations of ICRP publication 103 and 60 and specific k values were derived. DLP-based estimates differed by 4.5-16.56% and 5.2-15.8% relatively to ICRP 60 and 103, respectively. The derived k factors calculated from TLD measurements were 0.0148, 0.015, 0.0166, and 0.0148 for protocol 1, 2, 3 and 4, respectively. Effective dose estimations by ICRP 103 and 60 for single-energy and dual-energy protocols show a difference of less than 0.04mSv. Estimates of E based on DLP work equally well for single-energy, high-pitch and dual-energy CT examinations. The tube potential definitely affects effective dose in a substantial way. Effective dose estimations by ICRP 103 and 60 for both single-energy and dual-energy examinations differ not more than 0.04mSv. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  11. Radiation dose reduction in a neonatal intensive care unit in computed radiography.

    Science.gov (United States)

    Frayre, A S; Torres, P; Gaona, E; Rivera, T; Franco, J; Molina, N

    2012-12-01

    The purpose of this study was to evaluate the dose received by chest x-rays in neonatal care with thermoluminescent dosimetry and to determine the level of exposure where the quantum noise level does not affect the diagnostic image quality in order to reduce the dose to neonates. In pediatric radiology, especially the prematurely born children are highly sensitive to the radiation because of the highly mitotic state of their cells; in general, the sensitivity of a tissue to radiation is directly proportional to its rate of proliferation. The sample consisted of 208 neonatal chest x-rays of 12 neonates admitted and treated in a Neonatal Intensive Care Unit (NICU). All the neonates were preterm in the range of 28-34 weeks, with a mean of 30.8 weeks. Entrance Surface Doses (ESD) values for chest x-rays are higher than the DRL of 50 μGy proposed by the National Radiological Protection Board (NRPB). In order to reduce the dose to neonates, the optimum image quality was achieved by determining the level of ESD where level noise does not affect the diagnostic image quality. The optimum ESD was estimated for additional 20 chest x-rays increasing kVp and reducing mAs until quantum noise affects image quality. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Doses of emergency exposure to the USSR Navy personnel

    International Nuclear Information System (INIS)

    Skaletskiy, Yuriy

    2013-01-01

    Radiological consequences of the Soviet Navy accidents are significant and the number of acute radiation syndrome (ARS) cases is comparable to the number of ARS cases to Chernobyl catastrophe witness and clean-up workers in 1986. Results of a careful clinical-epidemiological examination of the personnel overexposed in the Navy accidents not only have value of radiobiology and radiation medicine specialists but can become a basis for the evaluation of the effectiveness of social protection strategy for the Chernobyl catastrophe clean-up workers. The officially registered exposure doses to persons affected by the Navy radiation accidents in some cases differ from the actual ones due to the imperfections of radiation monitoring facilities at the time of accidents. There was a tendency of clinical overstatement of the exposure doses resulting in diagnosis of 1st degree of ARS to persons who received external doses lower than 0.75. In some cases even 0.2 Gy was overstated as ARS severity for 2nd, 3rd, and 4th degrees. Exposure doses to the affected by the Navy accidents and their ARS severity degrees were evaluated with rather good accuracy. The use of modern method and approaches to the retrospective dose assessment allows more accurate evaluation of the submarine personnel exposure doses as well as verification of every ARS case, thus creating a necessary dosimetric basis for the organization of a correct radiation epidemiological investigation for persons of this contingent. Regretfully, tragic experience of nuclear power plants operation at the Navy vessels was not subject to analysis of specialists in order to improve nuclear safety, radiation protection, and emergency response organization in order to nuclear energy use in the USSR. (N.T.)

  13. Dose estimation using different ways of irradiation in a group of infants from zones affected by the Chernobyl accident

    International Nuclear Information System (INIS)

    Cruz Suarez, R.; Jova Sed, L.; Corripio, J.A.

    1993-01-01

    A dosimetry study is done to 4506 children from the Republic of Ukraine (69,3%), Belarus (8,1%) and Russian (22,5%) from 659 village and with ages between 1 and 17 years old. The study covers several stages. We can mention, for example, the dose estimation of iodine 121 in thyroids, the dose estimation for contamination with strontium 90 in the field and the calculation of the effective dose integrated in 70 years for the incorporation of cesium 137 in the body of the children, assuming a model of chronic incorporation. The estimation of the effective dose due to the strontium 90 was limited to a small group of 1314 children of those zones where the values of surface contamination of the field with this radionuclide are know

  14. Injury of the blood-testies barrier after low-dose-rate chronic radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Young Hoon; Bae Min Ji; Lee, Chang Geun; Yang, Kwang Mo; Jur, Kyu; Kim, Jong Sun [Dongnam Institute of Radiological and Medical Science, Busan (Korea, Republic of)

    2014-04-15

    The systemic effect of radiation increases in proportionally with the dose and dose rate. Little is known concerning the relationships between harmful effects and accumulated dose, which is derived from continuous low-dose rate radiation exposure. Recent our studies show that low-dose-rate chronic radiation exposure (3.49 mGy/h) causes adverse effects in the testis at a dose of 2 Gy (6 mGy/h). However, the mechanism of the low-dose-rate 2 Gy irradiation induced testicular injury remains unclear. The present results indicate that low-dose rate chronic radiation might affect the BTB permeability, possibly by decreasing levels of ZO-1, Occludin-1, and NPC-2. Furthermore, our results suggest that there is a risk of male infertility through BTB impairment even with low-dose-rate radiation if exposure is continuous.

  15. Dose distribution and mapping with 3D imaging presentation in intraoral and panoramic examinations

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hsiu-Ling [Department of Dental Medicine, Mackay Memorial Hospital, Taipei, Taiwan (China); Huang, Yung-Hui [Department of Medical Imaging and Radiological Science, I-Shou University, Kaohsiung, Taiwan (China); Wu, Tung-Hsin, E-mail: tung@ym.edu.tw [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Taipei 112 Taiwan (China); Wang, Shih-Yuan [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Taipei 112 Taiwan (China); Lee, Jason J.S., E-mail: jslee@ym.edu.tw [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Taipei 112 Taiwan (China)

    2011-10-01

    In current medical imaging applications, high quality images not only provide more diagnostic value for anatomic delineation but also offer functional information for treatment direction. However, this approach would potentially subscribe higher radiation dose in dental radiographies, which has been putatively associated with low-birth-weight during pregnancy, which affects the hypothalamus-pituitary-thyroid axis or thereby directly affects the reproductive organs. The aim of this study was to apply the high resolution 3-D image mapping technique to evaluate radiation doses from the following aspects: (1) verifying operating parameters of dental X-ray units, (2) measuring the leakage radiations and (3) mapping dose with 3-D radiographic imaging to evaluate dose distribution in head and neck regions. From the study results, we found that (1) leakage radiation from X-ray units was about 21.31{+-}15.24 mR/h (<100 mR/h), (2) error of actual tube voltage for 60 kVp setting was from 0.2% to 6.5%, with an average of 2.5% (<7%) and (3) the error of exposure time for a 0.5-1.5 s setting was within 0.7-8.5%, with an average of 7.3% (<10%) error as well. Our 3-D dose mapping demonstrated that dose values were relatively lower in soft tissues and higher in bone surfaces compared with other investigations. Multiple causes could contribute to these variations, including irradiation geometry, image equipment and type of technique applied, etc. From the results, we also observed that larger accumulated doses were presented in certain critical organs, such as salivary gland, thyroid gland and bone marrow. Potential biological affects associated with these findings warrant further investigation.

  16. Dose distribution and mapping with 3D imaging presentation in intraoral and panoramic examinations

    Science.gov (United States)

    Chen, Hsiu-Ling; Huang, Yung-Hui; Wu, Tung-Hsin; Wang, Shih-Yuan; Lee, Jason J. S.

    2011-10-01

    In current medical imaging applications, high quality images not only provide more diagnostic value for anatomic delineation but also offer functional information for treatment direction. However, this approach would potentially subscribe higher radiation dose in dental radiographies, which has been putatively associated with low-birth-weight during pregnancy, which affects the hypothalamus-pituitary-thyroid axis or thereby directly affects the reproductive organs. The aim of this study was to apply the high resolution 3-D image mapping technique to evaluate radiation doses from the following aspects: (1) verifying operating parameters of dental X-ray units, (2) measuring the leakage radiations and (3) mapping dose with 3-D radiographic imaging to evaluate dose distribution in head and neck regions. From the study results, we found that (1) leakage radiation from X-ray units was about 21.31±15.24 mR/h (error of actual tube voltage for 60 kVp setting was from 0.2% to 6.5%, with an average of 2.5% (error of exposure time for a 0.5-1.5 s setting was within 0.7-8.5%, with an average of 7.3% (error as well. Our 3-D dose mapping demonstrated that dose values were relatively lower in soft tissues and higher in bone surfaces compared with other investigations. Multiple causes could contribute to these variations, including irradiation geometry, image equipment and type of technique applied, etc. From the results, we also observed that larger accumulated doses were presented in certain critical organs, such as salivary gland, thyroid gland and bone marrow. Potential biological affects associated with these findings warrant further investigation.

  17. Human dental pulp cell culture and cell transplantation with an alginate scaffold.

    Science.gov (United States)

    Kumabe, Shunji; Nakatsuka, Michiko; Kim, Gi-Seup; Jue, Seong-Suk; Aikawa, Fumiko; Shin, Je-Won; Iwai, Yasutomo

    2006-02-01

    Many studies on tissue stem cells have been conducted in the field of regenerative medicine, and some studies have indicated that cultured dental pulp mesenchymal cells secrete dentin matrix. In the present study we used alginate as a scaffold to transplant subcultured human dental pulp cells subcutaneously into the backs of nude mice. We found that when beta-glycerophosphate was added to the culture medium, dentin sialophosphoprotein mRNA coding dentin sialoprotein (DSP) was expressed. An increase in alkaline phosphatase, which is an early marker for odontoblast differentiation, was also demonstrated. At 6 weeks after implantation the subcutaneous formation of radio-opaque calcified bodies was observed in situ. Immunohistochemical and fine structure studies identified expression of type I collagen, type III collagen, and DSP in the mineralizing transplants. Isolated odontoblast-like cells initiated dentin-like hard tissue formation and scattered autolyzing apoptotic cells were also observed in the transplants. The study showed that subcultured dental pulp cells actively differentiate into odontoblast-like cells and induce calcification in an alginate scaffold.

  18. Isolated rat dental pulp cell culture and transplantation with an alginate scaffold.

    Science.gov (United States)

    Fujiwara, Shiro; Kumabe, Shunji; Iwai, Yasutomo

    2006-05-01

    Many studies have been conducted on tissue stem cells in the field of regenerative medicine, and cultured dental pulp mesenchymal cells have been reported to secrete dentin matrix. In the present study we used alginate as a scaffold to transplant subcultured rat dental-pulp-derived cells subcutaneously into the back of nude mice. We found that when beta-glycerophosphate was added to the culture medium, the mRNA of the dentin sialophosphoprotein (DSPP) gene coding dentin sialoprotein (DSP) and dentin phosphoprotein (DPP) was expressed, and an increase in alkaline phosphatase, an early marker of odontoblast differentiation, was also demonstrated. Six weeks after implantation, subcutaneous formation of radiopaque calcified bodies was observed in situ. Immunohistochemical and fine structure studies identified expression of type I collagen, type III collagen, and DSP in the mineralizing transplants, and isolated odontoblast-like cells began to form dentin-like hard tissue formation. Scattered autolyzing apoptotic cells were also observed in the transplants. The study showed that subcultured rat dental-pulp-derived cells actively differentiate into odontoblast-like cells and induce calcification in an alginate scaffold.

  19. Assessment of committed effective dose due to the ingestion of 210Po and 210Pb in consumed Lebanese fish affected by a phosphate fertilizer plant

    International Nuclear Information System (INIS)

    Aoun, M.; El Samad, O.; Bou Khozam, R.; Lobinski, R.

    2015-01-01

    Ingestion of radionuclides through seafood intake is a one of the sources contributing to the internal effective dose in the human organism. In order to evaluate the internal exposure and potential risks due to 210 Po and 210 Pb associated with fish consumption, these radionuclides were measured in commonly consumed fish species from a clean area and an area subjected to the impact of a Lebanese phosphate fertilizer plant. The highest concentration of 210 Pb was 98.7 Bq/kg fresh weight while 210 Po activity concentrations varied from 3.6 Bq/kg to 140 Bq/kg. A supplementary radiation exposure was detected; the highest committed effective dose due to 210 Po and 210 Pb was found to be 1110 μSv/y and 450 μSv/y, respectively. Moreover, the average mortality and morbidity risks due to the fish consuming were estimated. - Highlights: • Enrichment in 210 Po and 210 Pb in fish affected by a phosphate fertilizer plant. • Significant human exposure associated with the ingestion of fish. • Estimation of potential risks due to 210 Po and 210 Pb via fish consumption

  20. Dose sculpting with generalized equivalent uniform dose

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  1. Dose rate and total dose dependence of the 1/f noise performance of a GaAs operational amplifier during irradiation

    International Nuclear Information System (INIS)

    Hiemstra, D.M.

    1995-01-01

    A pictorial of a sectioned view of the torus of the International Thermonuclear Experimental Reactor (ITER) is shown. Maintenance and inspection of the reactor are required to be performed remotely. This is due to the high gamma radiation environment in vessel during inspection and maintenance activities. The custom GaAs operational amplifier is to be used to readout sensors on the in-vessel manipulator and inspection equipment. The gamma dose rate during maintenance and inspection is anticipated to be 3 Mrad(GaAs)/hour. Here, dose rate and total dose dependence of the 1/f noise performance of a custom GaAs MESFET operational amplifier during irradiation are presented. Dose rate dependent 1/f noise degradation during irradiation is believed to be due to electron trapping in deep levels, enhanced by backgating and shallow traps excited during irradiation. The reduction of this affect with accumulated total dose is believed to be due a reduction of deep level site concentration associated with substitutional oxygen. Post irradiation 1/f noise degradation is also presented.The generation-recombination noise observed post irradiation can be attributed to the production of shallow traps due to ionizing radiation

  2. Effects of sparse sampling schemes on image quality in low-dose CT

    International Nuclear Information System (INIS)

    Abbas, Sajid; Lee, Taewon; Cho, Seungryong; Shin, Sukyoung; Lee, Rena

    2013-01-01

    Purpose: Various scanning methods and image reconstruction algorithms are actively investigated for low-dose computed tomography (CT) that can potentially reduce a health-risk related to radiation dose. Particularly, compressive-sensing (CS) based algorithms have been successfully developed for reconstructing images from sparsely sampled data. Although these algorithms have shown promises in low-dose CT, it has not been studied how sparse sampling schemes affect image quality in CS-based image reconstruction. In this work, the authors present several sparse-sampling schemes for low-dose CT, quantitatively analyze their data property, and compare effects of the sampling schemes on the image quality.Methods: Data properties of several sampling schemes are analyzed with respect to the CS-based image reconstruction using two measures: sampling density and data incoherence. The authors present five different sparse sampling schemes, and simulated those schemes to achieve a targeted dose reduction. Dose reduction factors of about 75% and 87.5%, compared to a conventional scan, were tested. A fully sampled circular cone-beam CT data set was used as a reference, and sparse sampling has been realized numerically based on the CBCT data.Results: It is found that both sampling density and data incoherence affect the image quality in the CS-based reconstruction. Among the sampling schemes the authors investigated, the sparse-view, many-view undersampling (MVUS)-fine, and MVUS-moving cases have shown promising results. These sampling schemes produced images with similar image quality compared to the reference image and their structure similarity index values were higher than 0.92 in the mouse head scan with 75% dose reduction.Conclusions: The authors found that in CS-based image reconstructions both sampling density and data incoherence affect the image quality, and suggest that a sampling scheme should be devised and optimized by use of these indicators. With this strategic

  3. In utero and lactational exposure to low-dose genistein-vinclozolin mixture affects the development and growth factor mRNA expression of the submandibular salivary gland in immature female rats.

    Science.gov (United States)

    Kouidhi, Wided; Desmetz, Catherine; Nahdi, Afef; Bergès, Raymond; Cravedi, Jean-Pierre; Auger, Jacques; El May, Michèle; Canivenc-Lavier, Marie Chantal

    2012-06-01

    It has been suggested that hormonally controlled submandibular salivary gland (SSG) development and secretions may be affected by endocrine disruptor compounds. We investigated the effects of oral gestation-lactation exposure to 1 mg/kg body weight daily dose of the estrogenic soy-isoflavone genistein and/or the anti-androgenic food contaminant vinclozolin in female rats. The SSGs of female offspring were collected at postnatal day 35 to study gland morphogenesis and mRNA expression of sex-hormone receptors and endocrine growth factors as sex-dependent biomarkers. Because of high expression in neonatal SSG, mRNA expression of transforming growth factor α was also studied. Exposure to genistein, vinclozolin, or a genistein+vinclozolin mixture resulted in significantly lower numbers of striated ducts linked to an increase in their area and lower acinar proliferation (Ki-67-positive nuclei). Exposure to the mixture had the highest significant effects, which were particularly associated with repression of epidermal growth factor, nerve growth factor, and transforming growth factor α expression. In conclusion, early exposure to low doses of genistein and vinclozolin can affect glandular structure and endocrine gene mRNA expression in prepubertal SSG in female rats, and the effects are potentialized by the genistein+vinclozolin mixture. Our study provides the first evidence that SSG are targeted by both estrogenic and anti-androgenic disrupting compounds and are more sensitive to mixtures.

  4. SU-E-T-802: Verification of Implanted Cardiac Pacemaker Doses in Intensity-Modulated Radiation Therapy: Dose Prediction Accuracy and Reduction Effect of a Lead Sheet

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J [Dept. of Radiation Oncology, Konkuk University Medical Center, Seoul (Korea, Republic of); Chung, J [Dept. of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of)

    2015-06-15

    Purpose: To verify delivered doses on the implanted cardiac pacemaker, predicted doses with and without dose reduction method were verified using the MOSFET detectors in terms of beam delivery and dose calculation techniques in intensity-modulated radiation therapy (IMRT). Methods: The pacemaker doses for a patient with a tongue cancer were predicted according to the beam delivery methods [step-and-shoot (SS) and sliding window (SW)], intensity levels for dose optimization, and dose calculation algorithms. Dosimetric effects on the pacemaker were calculated three dose engines: pencil-beam convolution (PBC), analytical anisotropic algorithm (AAA), and Acuros-XB. A lead shield of 2 mm thickness was designed for minimizing irradiated doses to the pacemaker. Dose variations affected by the heterogeneous material properties of the pacemaker and effectiveness of the lead shield were predicted by the Acuros-XB. Dose prediction accuracy and the feasibility of the dose reduction strategy were verified based on the measured skin doses right above the pacemaker using mosfet detectors during the radiation treatment. Results: The Acuros-XB showed underestimated skin doses and overestimated doses by the lead-shield effect, even though the lower dose disagreement was observed. It led to improved dose prediction with higher intensity level of dose optimization in IMRT. The dedicated tertiary lead sheet effectively achieved reduction of pacemaker dose up to 60%. Conclusion: The current SS technique could deliver lower scattered doses than recommendation criteria, however, use of the lead sheet contributed to reduce scattered doses.Thin lead plate can be a useful tertiary shielder and it could not acuse malfunction or electrical damage of the implanted pacemaker in IMRT. It is required to estimate more accurate scattered doses of the patient with medical device to design proper dose reduction strategy.

  5. SU-E-T-802: Verification of Implanted Cardiac Pacemaker Doses in Intensity-Modulated Radiation Therapy: Dose Prediction Accuracy and Reduction Effect of a Lead Sheet

    International Nuclear Information System (INIS)

    Lee, J; Chung, J

    2015-01-01

    Purpose: To verify delivered doses on the implanted cardiac pacemaker, predicted doses with and without dose reduction method were verified using the MOSFET detectors in terms of beam delivery and dose calculation techniques in intensity-modulated radiation therapy (IMRT). Methods: The pacemaker doses for a patient with a tongue cancer were predicted according to the beam delivery methods [step-and-shoot (SS) and sliding window (SW)], intensity levels for dose optimization, and dose calculation algorithms. Dosimetric effects on the pacemaker were calculated three dose engines: pencil-beam convolution (PBC), analytical anisotropic algorithm (AAA), and Acuros-XB. A lead shield of 2 mm thickness was designed for minimizing irradiated doses to the pacemaker. Dose variations affected by the heterogeneous material properties of the pacemaker and effectiveness of the lead shield were predicted by the Acuros-XB. Dose prediction accuracy and the feasibility of the dose reduction strategy were verified based on the measured skin doses right above the pacemaker using mosfet detectors during the radiation treatment. Results: The Acuros-XB showed underestimated skin doses and overestimated doses by the lead-shield effect, even though the lower dose disagreement was observed. It led to improved dose prediction with higher intensity level of dose optimization in IMRT. The dedicated tertiary lead sheet effectively achieved reduction of pacemaker dose up to 60%. Conclusion: The current SS technique could deliver lower scattered doses than recommendation criteria, however, use of the lead sheet contributed to reduce scattered doses.Thin lead plate can be a useful tertiary shielder and it could not acuse malfunction or electrical damage of the implanted pacemaker in IMRT. It is required to estimate more accurate scattered doses of the patient with medical device to design proper dose reduction strategy

  6. From personnel dose to personal dose

    International Nuclear Information System (INIS)

    Hoefert, M.; Raffnsoe, R.C.; Tuyn, J.W.N.; Wittekind, D.

    1985-01-01

    From following the development of personnel doses at CERN over the past six years it has become evident that work in areas of induced radioactivity is the principal cause of exposure. The results of photon dose measurements free-in-air and around a phantom are presented and discussed in the light of new quantities in individual monitoring. The importance of these results, with respect to the practical situation, is discussed and the problem of phantom size is mentioned. Finally, the results of dose measurements in the phantom are presented, since such information is important in cases where it becomes necessary to transform personnel doses into personal doses. (author)

  7. A comparison of submicrometer particle dose between Australian and Italian people

    International Nuclear Information System (INIS)

    Buonanno, G.; Morawska, L.; Stabile, L.; Wang, L.; Giovinco, G.

    2012-01-01

    Alveolar and tracheobronchial-deposited submicrometer particle number and surface area data received by different age groups in Australia are shown. Activity patterns were combined with microenvironmental data through a Monte Carlo method. Particle number distributions for the most significant microenvironments were obtained from our measurement survey data and people activity pattern data from the Australian Human Activity Pattern Survey were used. Daily alveolar particle number (surface area) dose received by all age groups was equal to 3.0 × 10 10 particles (4.5 × 10 2 mm 2 ), varying slightly between males and females. In contrast to gender, the lifestyle was found to significantly affect the daily dose, with highest depositions characterizing adults. The main contribution was due to indoor microenvironments. Finally a comparison between Italian and Australian people in terms of received particle dose was reported; it shows that different cooking styles can affect dose levels: higher doses were received by Italians, mainly due to their particular cooking activity. - Highlights: ► Particle number and surface area deposition in alveolar and tracheobronchial areas. ► Activity pattern and microenvironment data combination by Monte Carlo simulation. ► Deposition increases as a function of age group: maximum value for 19–40 years old. ► Major contributions arise from cooking, eating and transportation activities. ► Italian people statistically experience a dose higher than Australian one. - Alveolar and tracheobronchial-deposited submicrometer particle doses, in terms of number and surface area, were evaluated through a Monte Carlo method for different age groups population in Brisbane, Australia and compared to previously published Italian data.

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

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

    Science.gov (United States)

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

    2010-09-01

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

  10. Estimation and comparison of effective dose (E) in standard chest CT by organ dose measurements and dose-length-product methods and assessment of the influence of CT tube potential (energy dependency) on effective dose in a dual-source CT

    International Nuclear Information System (INIS)

    Paul, Jijo; Banckwitz, Rosemarie; Krauss, Bernhard; Vogl, Thomas J.; Maentele, Werner; Bauer, Ralf W.

    2012-01-01

    Sv. Conclusion: Estimates of E based on DLP work equally well for single-energy, high-pitch and dual-energy CT examinations. The tube potential definitely affects effective dose in a substantial way. Effective dose estimations by ICRP 103 and 60 for both single-energy and dual-energy examinations differ not more than 0.04 mSv.

  11. Effect of gamma irradiation at doses of 5-15 kGy on the quality properties of durum wheat semolina

    International Nuclear Information System (INIS)

    Taha, S.A.

    1990-01-01

    Semolina purified from four durum wheat varieties were gamma-irradiated with doses of 0, 5, 10 and 15 kGy, i.e., dose levels expected to improve the colour of pasta products, suitable for reduction of microbial contamination, and high doses required for insect disinfestation. The irradiation resulted in significant losses in carotenoid content and oxidative enzyme activities. Gamma irradiation slightly affected the mixing properties, greatly reduced the gluten strength and adversely affected firmness of cooked pasta. Consequently, preservative gamma irradiation of durum wheat semolina should be limited to a maximum dose of 5 kGy. (author) 39 refs.; 3 tabs

  12. Radiation absorbed dose from medically administered radiopharmaceuticals

    International Nuclear Information System (INIS)

    Roedler, H.D.; Kaul, A.

    1975-01-01

    The use of radiopharmaceuticals for medical examinations is increasing. Surveys carried out in West Berlin show a 20% average yearly increase in such examinations. This implies an increased genetic and somatic radiation exposure of the population in general. Determination of radiation exposure of the population as well as of individual patients examined requires a knowledge of the radiation dose absorbed by each organ affected by each examination. An extensive survey of the literature revealed that different authors reported widely different dose values for the same defined examination methods and radiopharmaceuticals. The reason for this can be found in the uncertainty of the available biokinetic data for dose calculations and in the application of various mathematical models to describe the kinetics and calculation of organ doses. Therefore, the authors recalculated some of the dose values published for radiopharmaceuticals used in patients by applying biokinetic data obtained from exponential models of usable metabolism data reported in the literature. The calculation of organ dose values was done according to the concept of absorbed fractions in its extended form. For all radiopharmaceuticals used in nuclear medicine the energy dose values for the most important organs (ovaries, testicles, liver, lungs, spleen, kidneys, skeleton, total body or residual body) were recalculated and tabulated for the gonads, skeleton and critical or examined organs respectively. These dose values are compared with those reported in the literature and the reasons for the observed deviations are discussed. On the basis of recalculated dose values for the gonads and bone-marrow as well as on the basis of results of statistical surveys in West Berlin, the genetically significant dose and the somatically (leukemia) significant dose were calculated for 1970 and estimated for 1975. For 1970 the GSD was 0.2 mrad and the LSD was 0.7 mrad. For 1975 the GSD is estimated at < 0.5 mrad and the

  13. Ameliorative effects of low dose/low dose-rate irradiation on reactive oxygen species-related diseases model mice

    International Nuclear Information System (INIS)

    Nomura, Takaharu

    2008-01-01

    Living organisms have developed complex biological system which protects themselves against environmental radiation, and irradiation with proper dose, dose-rate and irradiation time can stimulate their biological responses against oxidative stress evoked by the irradiation. Because reactive oxygen species are involved in various human diseases, non-toxic low dose/low dose-rate radiation can be utilized for the amelioration of such diseases. In this study, we used mouse experimental models for fatty liver, nephritis, diabetes, and ageing to elucidate the ameliorative effect of low dose/low dose-rate radiation in relation to endogenous antioxidant activity. Single irradiation at 0.5 Gy ameliorates carbon tetrachloride-induced fatty liver. The irradiation increases hepatic anti-oxidative system involving glutathione and glutathione peroxidase, suggesting that endogenous radical scavenger is essential for the ameliorative effect of low dose radiation on carbon tetrachloride-induced fatty liver. Single irradiation at 0.5 Gy ameliorates ferric nitrilotriacetate-induced nephritis. The irradiation increases catalase and decreases superoxide dismutase in kidney. The result suggests that low dose radiation reduced generation of hydroxide radical generation by reducing cellular hydroperoxide level. Single irradiation at 0.5 Gy at 12 week of age ameliorates incidence of type I diabetes in non-obese diabetic (NOD) mice through the suppression of inflammatory activity of splenocytes, and resultant apoptosis of β-cells in pancreas. The irradiation activities of superoxide dismutase and catalase, which coordinately diminish intracellular reactive oxygen species. Continuous irradiation at 0.70 mGy/hr from 10 week of age elongates life span, and suppresses alopecia in type II diabetesmice. The irradiation improved glucose clearance without affecting insulin-resistance, and increased pancreatic catalase activity. The results suggest that continuous low dose-rate irradiation protect

  14. MO-D-213-04: The Proximity to the Skin of PTV Affects PTV Coverage and Skin Dose for TomoTherapy

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, T; Higgins, P; Watanabe, Y [University of Minnesota, Minneapolis, MN (United States)

    2015-06-15

    Purpose: The proximity to the skin surface of the PTV for the patients with skin disease could be a concern in terms of the PTV coverage and actual surface dose (SD). IMRT optimization algorithms increase the beam intensity close to the skin in order to compensate for lack of scattering material, leading to enhanced SD but potential hot spots. This study aims to investigate the effect of PTV proximity to the skin on planning and measured SD Methods: All measurements were done for 6 MV X-ray beam of Helical TomoTherapy. An anthropomorphic phantom was scanned in a CT simulator in a routine manner with thermoplastic mask immobilization. PTVs were created with varying distances to the skin of 0 mm -(PTV1), 1 mm- (PTV2), 2 mm-(PTV3) and 3 mm-(PTV4). Also, a 5 mm bolus was used with PTV1 (PTV5). All planning constraints were kept the same in all studies (hard constraint: 95% of the prescription dose covered 95% of the PTV). Gafchromic film (EBT3) was placed under the mask on the phantom surface, and the resulting dose was estimated using RIT software. Results: Optimizing the dose using different PTVs lead to average planned target doses of 10.8, 10.3, 10.2, 10.3 and 10.0 Gy, with maximum doses 12.2, 11.2, 11.1, 11.1 and 10.0 Gy for PTV1, PTV2, PTV3, PTV4 and PTV5, respectively. EBT3 measurements indicated a significant decrease of SD with skin distance by 12.7% (PTV1), 21.9% (PTV2), 24.8% (PTV3) and 28.4% (PTV4) comparing to prescription dose. Placement of a 5 mm bolus on the phantom surface resulted in a SD close to prescribed (+0.5%). Conclusion: This work provides a clear demonstration of the relationship between the skin dose and the PTV to the skin distance. The results indicate the necessity of a bolus even for TomoTherapy when high skin dose is required.

  15. MO-D-213-04: The Proximity to the Skin of PTV Affects PTV Coverage and Skin Dose for TomoTherapy

    International Nuclear Information System (INIS)

    Reynolds, T; Higgins, P; Watanabe, Y

    2015-01-01

    Purpose: The proximity to the skin surface of the PTV for the patients with skin disease could be a concern in terms of the PTV coverage and actual surface dose (SD). IMRT optimization algorithms increase the beam intensity close to the skin in order to compensate for lack of scattering material, leading to enhanced SD but potential hot spots. This study aims to investigate the effect of PTV proximity to the skin on planning and measured SD Methods: All measurements were done for 6 MV X-ray beam of Helical TomoTherapy. An anthropomorphic phantom was scanned in a CT simulator in a routine manner with thermoplastic mask immobilization. PTVs were created with varying distances to the skin of 0 mm -(PTV1), 1 mm- (PTV2), 2 mm-(PTV3) and 3 mm-(PTV4). Also, a 5 mm bolus was used with PTV1 (PTV5). All planning constraints were kept the same in all studies (hard constraint: 95% of the prescription dose covered 95% of the PTV). Gafchromic film (EBT3) was placed under the mask on the phantom surface, and the resulting dose was estimated using RIT software. Results: Optimizing the dose using different PTVs lead to average planned target doses of 10.8, 10.3, 10.2, 10.3 and 10.0 Gy, with maximum doses 12.2, 11.2, 11.1, 11.1 and 10.0 Gy for PTV1, PTV2, PTV3, PTV4 and PTV5, respectively. EBT3 measurements indicated a significant decrease of SD with skin distance by 12.7% (PTV1), 21.9% (PTV2), 24.8% (PTV3) and 28.4% (PTV4) comparing to prescription dose. Placement of a 5 mm bolus on the phantom surface resulted in a SD close to prescribed (+0.5%). Conclusion: This work provides a clear demonstration of the relationship between the skin dose and the PTV to the skin distance. The results indicate the necessity of a bolus even for TomoTherapy when high skin dose is required

  16. Phentermine, sibutramine and affective disorders.

    Science.gov (United States)

    An, Hoyoung; Sohn, Hyunjoo; Chung, Seockhoon

    2013-04-01

    A safe and effective way to control weight in patients with affective disorders is needed, and phentermine is a possible candidate. We performed a PubMed search of articles pertaining to phentermine, sibutramine, and affective disorders. We compared the studies of phentermine with those of sibutramine. The search yielded a small number of reports. Reports concerning phentermine and affective disorders reported that i) its potency in the central nervous system may be comparatively low, and ii) it may induce depression in some patients. We were unable to find more studies on the subject; thus, it is unclear presently whether phentermine use is safe in affective disorder patients. Reports regarding the association of sibutramine and affective disorders were slightly more abundant. A recent study that suggested that sibutramine may have deleterious effects in patients with a psychiatric history may provide a clue for future phentermine research. Three explanations are possible concerning the association between phentermine and affective disorders: i) phentermine, like sibutramine, may have a depression-inducing effect that affects a specific subgroup of patients, ii) phentermine may have a dose-dependent depression-inducing effect, or iii) phentermine may simply not be associated with depression. Large-scale studies with affective disorder patients focusing on these questions are needed to clarify this matter before investigation of its efficacy may be carried out and it can be used in patients with affective disorders.

  17. Occupational eye lens doses in interventional cardiology. A multicentric study

    International Nuclear Information System (INIS)

    Sánchez, R M; Vano, E; Fernández, J M; Pifarré, X; Ordiales, J M; Rovira, J J; Carrera, F; Goicolea, J; Fernández-Ortiz, A

    2016-01-01

    New European regulation regarding radiological protection of workers and more specifically the new occupational dose limit for the eye lens recently reduced to 20 mSv yr −1 may affect interventional cardiologists. This paper presents a set of measurements of occupational doses performed in five interventional cardiology centres and then compared with the new dose limit. The measurement of occupational doses was performed over the apron at chest level using electronic dosemeters recording H p (10). In one of the centres, scatter dose at goggles was also measured with optically stimulated luminescence dosemeters calibrated in terms of H p (0.07). An average H p (10) over the apron of 46 μSv/procedure was measured for cardiologists. Lower doses were noted in other professionals like second cardiologists, nurses or anaesthetists. Procedures for valvular and other structural heart diseases involved the highest occupational doses, averaging over 100 μSv/procedure. Important differences in occupational doses among centres may be indicative of different radiation protection habits. The new occupational dose limit for the eye lens is likely to be exceeded by those among the interventionalists who do not use protection tools (ceiling suspended screen and/or goggles) even with standard workloads. (paper)

  18. Radiation mutagenesis in lavender. I.Dose and emissive power as affecting the radiosensitivity of lavender seeds in gamma-ray treatment

    International Nuclear Information System (INIS)

    Tsvetkov, R.

    1977-01-01

    The radiosensitivity has been investigated of dormant seeds of the widely distributed aboriginal Hemus and Karlovo varieties and of the Soviet Stepnaya lavender variety in treatment with gamma rays using 60 Co. Doses within 1 to 100 kRad are applied at different emissive power of the emitter. Both irradiated and nonirradiated control seeds are gibberellic acid treated. The dynamics of seed sprouting is followed up. The number of survived plants and peculiarities of their growth are registered. The radiosensitivity of Lavandula vera D.C. seeds is modified by the emissive power in equal doses applied. Stepnaya variety showed highest resistance, followed by Karlovo and Hemus varieties. Doses are ascertained with a stimulating, inhibiting, semilethal and lethal effect in regard to the separate varietoes. Both stimulation and injuring prove to be of saltatory character. The radiation injuring of doses with an inhibitory, semilethal and lethal effect positively correlate with the dose of all tested emissive powers of the gamma-emitter. (author)

  19. Assessment of skin dose modification caused by application of immobilizing cast in head and neck radiotherapy

    International Nuclear Information System (INIS)

    Soleymanifard, Shokouhozaman; Toossi, Mohammad T.B.; Khosroabadi, Mohsen; Noghreiyan, Atefeh Vejdani; Shahidsales, Soodabeh; Tabrizi, Fatemeh Varshoee

    2014-01-01

    Skin dose assessment for radiotherapy patients is important to ensure that the dose received by skin is not excessive and does not cause skin reactions. Immobilizing casts may have a buildup effect, and can enhance the skin dose. This study has quantified changes to the surface dose as a result of head and neck immobilizing casts. Medtech and Renfu casts were stretched on the head of an Alderson Rando-Phantom. Irradiation was performed using 6 and 15 MV X-rays, and surface dose was measured by thermoluminescence dosimeters. In the case of 15MV photons, immobilizing casts had no effect on the surface dose. However, the mean surface dose increase reached up to 20 % when 6MV X-rays were applied. Radiation incidence angle, thickness, and meshed pattern of the casts affected the quantity of dose enhancement. For vertical beams, the surface dose increase was more than tangential beams, and when doses of the points under different areas of the casts were analysed separately, results showed that only doses of the points under the thick area had been changed. Doses of the points under the thin area and those within the holes were identical to the same points without immobilizing casts. Higher dose which was incurred due to application of immobilizing casts (20 %) would not affect the quality of life and treatment of patients whose head and neck are treated. Therefore, the benefits of head and neck thermoplastic casts are more than their detriments. However, producing thinner casts with larger holes may reduce the dose enhancement effect.

  20. Dose deviations caused by positional inaccuracy of multileaf collimator in intensity modulated radiotherapy

    International Nuclear Information System (INIS)

    Wang, H.C.; Chui, C.S.; Tsai, H.Y.; Chen, C.H.; Tsai, L.F.

    2008-01-01

    Introduction: Multileaf collimator (MLC) is currently a widely used system in the delivery of intensity modulated radiotherapy (IMRT). The accuracy of the multileaf position plays an important role in the final outcome of the radiation treatment. According to ICRU recommendation, a dose inaccuracy over than 5% of prescribed dose affects treatment results. In order to quantify the influence of leaf positional errors on dose distribution, we set different MLC positional inaccuracy from 0 to 6 mm for step-and-shoot IMRT in clinical cases. Two-dimensional dose distributions of radiotherapy plans with different leaf displacements generated with a commercial treatment planning system. And verification films were used to measure two-dimensional dose distributions. Then a computerized dose comparison system will be introduced to analyze the dose deviations. Materials/methods: We assumed MLC positional inaccuracy from 0 to 6 mm for step-and-shoot IMRT in clinical cases by simulating the different leaf displacements with a commercial treatment planning system. Then we transferred the treatment plans with different leaf offset that may be happened in clinical situation to linear accelerator. Verification films (Kodat EDR2) were well positioned within solid water phantoms to be irradiated by the simulated plans. The films were scanned to display two-dimensional dose distributions. Finally, we compared with the dose distributions with MLC positional inaccuracy by a two-dimensional dose comparison software to analyze the deviations in Gamma indexes and normalized agreement test (NAT) values. Results: In general, the data show that larger leaf positional error induces larger dose error. More fields used for treatment generate lesser errors. Besides, leaf position relative to a field influences the degree of dose error. A leaf lying close to the border of a field leads to a more significant dose deviation than a leaf in the center. Algorithms for intensity modulation also affect

  1. Low-dose cyclophosphamide administered as daily or single dose enhances the antitumor effects of a therapeutic HPV vaccine

    Science.gov (United States)

    Peng, Shiwen; Lyford-Pike, Sofia; Akpeng, Belinda; Wu, Annie; Hung, Chien-Fu; Hannaman, Drew; Saunders, John R.; Wu, T.-C.

    2012-01-01

    Although therapeutic HPV vaccines are able to elicit systemic HPV-specific immunity, clinical responses have not always correlated with levels of vaccine-induced CD8+ T cells in human clinical trials. This observed discrepancy may be attributable to an immunosuppressive tumor microenvironment in which the CD8+ T cells are recruited. Regulatory T cells (Tregs) are cells that can dampen cytotoxic CD8+ T-cell function. Cyclophosphamide (CTX) is a systemic chemotherapeutic agent, which can eradicate immune cells, including inhibitory Tregs. The optimal dose and schedule of CTX administration in combination with immunotherapy to eliminate the Treg population without adversely affecting vaccine-induced T-cell responses is unknown. Therefore, we investigated various dosing and administration schedules of CTX in combination with a therapeutic HPV vaccine in a preclinical tumor model. HPV tumor-bearing mice received either a single preconditioning dose or a daily dose of CTX in combination with the pNGVL4a-CRT/E7(detox) DNA vaccine. Both single and daily dosing of CTX in combination with vaccine had a synergistic anti-tumor effect as compared to monotherapy alone. The potent antitumor responses were attributed to the reduction in Treg frequency and increased infiltration of HPV16 E7-specific CD8+ T cells, which led to higher ratios of CD8+/Treg and CD8+/CD11b+Gr-1+ myeloid-derived suppressor cells (MDSCs). There was an observed trend toward decreased vaccine-induced CD8+ T-cell frequency with daily dosing of CTX. We recommend a single, preconditioning dose of CTX prior to vaccination due to its efficacy, ease of administration, and reduced cumulative adverse effect on vaccine-induced T cells. PMID:23011589

  2. Proton Therapy Dose Characterization and Verification

    Science.gov (United States)

    2016-10-01

    necrosis may be confined to the white matter, both grey and white matter is affected by vascular changes. It is very difficult to predict the severity of...treatment planning may contribute to the risk of late neurocognitive injury. Radiation dose-dependent subclinical vascular effects have been reported...changes in vascular perfusion, in spectroscopic parameters of neuronal injury, and in changes in the degree and directionality of tissue water

  3. Cellular Stress to Low Gamma-ray Dose

    International Nuclear Information System (INIS)

    Manzanares-Acuna, E.; Vega-Carrillo, H. R.; Letechipia de Leon, C.; Guzman Enriquez, L. J.; Garcia-Talavera, M.

    2004-01-01

    The purpose of this study was to evaluate the effect of low gamma ray intensity upon Hsp 70 expression in human lymphocytes. the heat shock proteins (Hsp) family, are a group of proteins present in all living organism, therefore there are highly conserved and are related to adaptation and evolution. At cellular level these proteins acts as chaperones correcting denatured proteins. when a stress agent, such heavy metals, UV, heat, etc. is affecting a cell a response to this aggression is triggered through overexpression of Hsp. Several studies has been carried out in which the cellular effect are observed, mostly of these studies uses large doses, but very few studies are related with low doses. Blood of healthy volunteers was obtained and the lymphocytes were isolated by ficoll-histopaque gradient. Experimental lots were irradiated in a ''137Cs gamma-ray. Hsp70 expression was found since 0.5 cGy, indicating a threshold to very low doses of gamma rays. (Author) 27 refs

  4. Radiation dose delivery verification in the treatment of carcinoma-cervix

    International Nuclear Information System (INIS)

    Shrotriya, D.; Srivastava, R. N. L.; Kumar, S.

    2015-01-01

    The accurate dose delivery to the clinical target volume in radiotherapy can be affected by various pelvic tissues heterogeneities. An in-house heterogeneous woman pelvic phantom was designed and used to verify the consistency and computational capability of treatment planning system of radiation dose delivery in the treatment of cancer cervix. Oncentra 3D-TPS with collapsed cone convolution (CCC) dose calculation algorithm was used to generate AP/PA and box field technique plan. the radiation dose was delivered by Primus Linac (Siemens make) employing high energy 15 MV photon beam by isocenter technique. A PTW make, 0.125cc ionization chamber was used for direct measurements at various reference points in cervix, bladder and rectum. The study revealed that maximum variation between computed and measured dose at cervix reference point was 1% in both the techniques and 3% and 4% variation in AP/PA field and 5% and 4.5% in box technique at bladder and rectum points respectively

  5. Radiation dose delivery verification in the treatment of carcinoma-cervix

    Science.gov (United States)

    Shrotriya, D.; Kumar, S.; Srivastava, R. N. L.

    2015-06-01

    The accurate dose delivery to the clinical target volume in radiotherapy can be affected by various pelvic tissues heterogeneities. An in-house heterogeneous woman pelvic phantom was designed and used to verify the consistency and computational capability of treatment planning system of radiation dose delivery in the treatment of cancer cervix. Oncentra 3D-TPS with collapsed cone convolution (CCC) dose calculation algorithm was used to generate AP/PA and box field technique plan. the radiation dose was delivered by Primus Linac (Siemens make) employing high energy 15 MV photon beam by isocenter technique. A PTW make, 0.125cc ionization chamber was used for direct measurements at various reference points in cervix, bladder and rectum. The study revealed that maximum variation between computed and measured dose at cervix reference point was 1% in both the techniques and 3% and 4% variation in AP/PA field and 5% and 4.5% in box technique at bladder and rectum points respectively.

  6. Radiation dose delivery verification in the treatment of carcinoma-cervix

    Energy Technology Data Exchange (ETDEWEB)

    Shrotriya, D., E-mail: shrotriya2007@gmail.com; Srivastava, R. N. L. [Department of Radiotherapy, J.K. Cancer Institute Kanpur-208019 (India); Kumar, S. [Department of Physics, Christ Church College, Kanpur-208001 (India)

    2015-06-24

    The accurate dose delivery to the clinical target volume in radiotherapy can be affected by various pelvic tissues heterogeneities. An in-house heterogeneous woman pelvic phantom was designed and used to verify the consistency and computational capability of treatment planning system of radiation dose delivery in the treatment of cancer cervix. Oncentra 3D-TPS with collapsed cone convolution (CCC) dose calculation algorithm was used to generate AP/PA and box field technique plan. the radiation dose was delivered by Primus Linac (Siemens make) employing high energy 15 MV photon beam by isocenter technique. A PTW make, 0.125cc ionization chamber was used for direct measurements at various reference points in cervix, bladder and rectum. The study revealed that maximum variation between computed and measured dose at cervix reference point was 1% in both the techniques and 3% and 4% variation in AP/PA field and 5% and 4.5% in box technique at bladder and rectum points respectively.

  7. Doses of Chernobyl liquidators: Ukrainian prospective

    International Nuclear Information System (INIS)

    Chumak, Vadim V.; Bakhanova, Elena V.; Sholom, Sergey V.; Bouville, Andre; Luckyanov, Nickolas K.; Skaletsky, Yuri N.; Kryuchkov, Viktor P.

    2008-01-01

    least at group level. However, as anticipated, in about 10% of cases the dose records were artificially assigned. Analysis of such major discrepancies showed that the ratio of the number of overestimated doses to those that were underestimated is about 20:1. As a rule unrealistically high doses were assigned to some specific 'privileged' groups of military liquidators (i.e., commanders, logistics specialists, etc.). Such groups can, in principle, be isolated and excluded from analysis. Analysis of doses retrospectively reconstructed using the RADRUE technique shows that the second numerous category (∼28%) were civilians sent on mission to the 30-km zone (CSOM). These liquidators performed a broad variety of tasks at various times and places; as a result the dose distribution for this category is very broad. About 10% of Ukrainian liquidators took part in clean-up activities in April-May 1986 and generally received higher doses. Another 10% of liquidators belong to 'mixed' category, which is characterized by several work sessions (missions) that were defined by differing roles (tasks) during Chernobyl clean-up. Other categories, like victims of the accident, early respondents, and professional atomic workers contribute ≤1% of the total number of Ukrainian liquidators and their doses do not significantly affect the overall dose distribution. The data collected in the aforementioned studies allows reevaluation of dose distribution for Ukrainian liquidators. The new distribution is quite different from the previously circulated dose distribution derived from incomplete and biased ODRs stored in the SRU. (author)

  8. Hydrocortisone infusion exerts dose- and sex-dependent effects on attention to emotional stimuli.

    Science.gov (United States)

    Breitberg, Alaina; Drevets, Wayne C; Wood, Suzanne E; Mah, Linda; Schulkin, Jay; Sahakian, Barbara J; Erickson, Kristine

    2013-03-01

    Glucocorticoid administration has been shown to exert complex effects on cognitive and emotional processing. In the current study we investigated the effects of glucocorticoid administration on attention towards emotional words, using an Affective Go/No-go task on which healthy humans have shown an attentional bias towards positive as compared to negative words. Healthy volunteers received placebo and either low-dose (0.15mg/kg) or high-dose (0.45mg/kg) hydrocortisone intravenously during two separate visits in a double-blind, randomized design. Seventy-five minutes post-infusion, the subjects performed tests of attention (Rapid Visual Information Processing [RVIP]), spatial working memory (Spatial Span) and emotional processing (Affective Go/No-go task [AGNG]). On the attention task, performance was impaired under both hydrocortisone doses relative to placebo, though the effect on error rate was not significant after controlling for age; Spatial Span performance was unaffected by hydrocortisone administration. On the AGNG task, relative to the placebo condition the low-dose hydrocortisone infusion decreased response time to emotional words while high-dose hydrocortisone increased response time. In the females specifically, both high and low dose hydrocortisone administration attenuated the normal attentional bias toward positively valenced words. These data suggest that, in healthy women, the modulation of attention by the emotional salience of stimuli is influenced by glucocorticoid hormone concentrations. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Dose and perceived image quality in chest radiography

    International Nuclear Information System (INIS)

    Veldkamp, Wouter J.H.; Kroft, Lucia J.M.; Geleijns, Jacob

    2009-01-01

    Chest radiography is the most commonly performed diagnostic X-ray examination. The radiation dose to the patient for this examination is relatively low but because of its frequent use, the contribution to the collective dose is considerable. Consequently, optimization of dose and image quality offers a challenging area of research. In this article studies on dose reduction, different detector technologies, optimization of image acquisition and new technical developments in image acquisition and post processing will be reviewed. Studies indicate that dose reduction in PA chest images to at least 50% of commonly applied dose levels does not affect diagnosis in the lung fields; however, dose reduction in the mediastinum, upper abdomen and retrocardiac areas appears to directly deteriorate diagnosis. In addition to patient dose, also the design of the various digital detectors seems to have an effect on image quality. With respect to image acquisition, studies showed that using a lower tube voltage improves visibility of anatomical structures and lesions in digital chest radiographs but also increases the disturbing appearance of ribs. New techniques that are currently being evaluated are dual energy, tomosynthesis, temporal subtraction and rib suppression. These technologies may improve diagnostic chest X-ray further. They may for example reduce the negative influence of over projection of ribs, referred to as anatomic noise. In chest X-ray this type of noise may be the dominating factor in the detection of nodules. In conclusion, optimization and new developments will enlarge the value of chest X-ray as a mainstay in the diagnosis of chest diseases.

  10. Flight attendant radiation dose from solar particle events.

    Science.gov (United States)

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

    2014-08-01

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

  11. A subconvulsive dose of kainate selectively compromises astrocytic metabolism in the mouse brain in vivo.

    Science.gov (United States)

    Walls, Anne B; Eyjolfsson, Elvar M; Schousboe, Arne; Sonnewald, Ursula; Waagepetersen, Helle S

    2014-08-01

    Despite the well-established use of kainate as a model for seizure activity and temporal lobe epilepsy, most studies have been performed at doses giving rise to general limbic seizures and have mainly focused on neuronal function. Little is known about the effect of lower doses of kainate on cerebral metabolism and particularly that associated with astrocytes. We investigated astrocytic and neuronal metabolism in the cerebral cortex of adult mice after treatment with saline (controls), a subconvulsive or a mildly convulsive dose of kainate. A combination of [1,2-(13)C]acetate and [1-(13)C]glucose was injected and subsequent nuclear magnetic resonance spectroscopy of cortical extracts was employed to distinctively map astrocytic and neuronal metabolism. The subconvulsive dose of kainate led to an instantaneous increase in the cortical lactate content, a subsequent reduction in the amount of [4,5-(13)C]glutamine and an increase in the calculated astrocytic TCA cycle activity. In contrast, the convulsive dose led to decrements in the cortical content and (13)C labeling of glutamate, glutamine, GABA, and aspartate. Evidence is provided that astrocytic metabolism is affected by a subconvulsive dose of kainate, whereas a higher dose is required to affect neuronal metabolism. The cerebral glycogen content was dose-dependently reduced by kainate supporting a role for glycogen during seizure activity.

  12. A review of occupational dose assessment uncertainties and approaches

    International Nuclear Information System (INIS)

    Anderson, R. W.

    2004-01-01

    The Radiological Protection Practitioner (RPP) will spend a considerable proportion of his time predicting or assessing retrospective radiation exposures to occupational personnel for different purposes. The assessments can be for a variety of purposes, such as to predict doses for occupational dose control, or project design purposes or to make retrospective estimates for the dose record, or account for dosemeters which have been lost or damaged. There are other less frequent occasions when dose assessment will be required such as to support legal cases and compensation claims and to provide the detailed dose information for epidemiological studies. It is important that the level of detail, justification and supporting evidence in the dose assessment is suitable for the requirements. So for instance, day to day operational dose assessments often rely mainly on the knowledge of the RPP in discussion with operators whilst at the other end of the spectrum a historical dose assessment for a legal case will require substantial research and supporting evidence for the estimate to withstand forensic challenge. The robustness of the assessment will depend on many factors including a knowledge of the work activities, the radiation dose uptake and field characteristics; all of which are affected by factors such as the time elapsed, the memory of operators and the dosemeters employed. This paper reviews the various options and uncertainties in dose assessments ranging from use of personal dosimetry results to the development of upper bound assessments. The level of assessment, the extent of research and the evidence adduced should then be appropriate to the end use of the estimate. (Author)

  13. Peripheral doses from pediatric IMRT

    International Nuclear Information System (INIS)

    Klein, Eric E.; Maserang, Beth; Wood, Roy; Mansur, David

    2006-01-01

    0.47-0.94) doses ∼[0.4-1.8 cGy]/[0.9-2.9 cGy]/fraction, respectively. Prior phantom reports are for fields 10 cm or greater, while pediatric central nervous system fields range from 4 to 7 cm, and effectively much smaller for IMRT (2-6 cm). Peripheral dose in close proximity (<10 cm from the field edge) is dominated by internal scatter; therefore, field-size differences overwhelm phantom size affects and increased MU. Distant peripheral dose, dominated by head leakage, was higher than predicted, even when accounting for MUs (∼factor of 3) likely due to the pediatric phantom size. The ratio of the testes dose ranged from 3.3-5.3 for IMRT/conventional. PD to OAR for pediatric IMRT cannot be predicted from large-field full phantom studies. For regional OAR, doses are likely lower than predicted by existing ''large field'' data, while the distant PD is higher

  14. Radiological Evaluation of the effects of varied doses of Celecoxib on fracture healing in dogs

    Directory of Open Access Journals (Sweden)

    Edwin Aihanuwa Uwagie-Ero and Rapheal Chukwujekwu Kene

    2011-04-01

    Full Text Available To determine if Cyclooxygenase -2 (COX-2 functions in fracture healing, 10 dogs were treated with COX-2-selective nonsteroidal anti-inflammatory drugs (Celecoxib to reduce and stop COX-2-dependent prostaglandin production. Radiographic testing evaluation determined that fracture healing was not affected in dogs treated with a low dose of COX-2-selective NSAIDs (celecoxib and delayed union was observed in dogs treated with a high dose of COX-2-selective NSAIDs (celecoxib. Celecoxib dose of 5 mg/kg/day did not affect fracture callus formed in the study group and did not cause a significant increase in the proportion of delayed unions, however, at a dose of 10 mg/kg/day it reduced the rate of fracture callus formation and significantly increased the proportion of delayed unions for dogs in the group. [Veterinary World 2011; 4(2.000: 75-76

  15. [Dose rate-dependent cellular and molecular effects of ionizing radiation].

    Science.gov (United States)

    Przybyszewski, Waldemar M; Wideł, Maria; Szurko, Agnieszka; Maniakowski, Zbigniew

    2008-09-11

    The aim of radiation therapy is to kill tumor cells while minimizing damage to normal cells. The ultimate effect of radiation can be apoptotic or necrotic cell death as well as cytogenetic damage resulting in genetic instability and/or cell death. The destructive effects of radiation arise from direct and indirect ionization events leading to peroxidation of macromolecules, especially those present in lipid-rich membrane structures as well as chromatin lipids. Lipid peroxidative end-products may damage DNA and proteins. A characteristic feature of radiation-induced peroxidation is an inverse dose-rate effect (IDRE), defined as an increase in the degree of oxidation(at constant absorbed dose) accompanying a lower dose rate. On the other hand, a low dose rate can lead to the accumulation of cells in G2, the radiosensitive phase of the cell cycle since cell cycle control points are not sensitive to low dose rates. Radiation dose rate may potentially be the main factor improving radiotherapy efficacy as well as affecting the intensity of normal tissue and whole-body side effects. A better understanding of dose rate-dependent biological effects may lead to improved therapeutic intervention and limit normal tissue reaction. The study reviews basic biological effects that depend on the dose rate of ionizing radiation.

  16. Analysis of the main factors affecting the evaluation of the dose in workplaces: the case of tourist caves

    International Nuclear Information System (INIS)

    Sainz, C.; Santiago Quindos, L.; Fuente, I.; Nicolas, J.; Quindos, L.

    2006-01-01

    Since 2001, Spanish law incorporated EURATOM basic standards for radiological protection, which include a request at the European Communities Member States to determine the working places on which exposure to natural radiation is significant. On Title VII (BOE 178/2001) radiation coming from natural sources has analogous role than radiation emitted from artificial ones used to. High concentrations of radon exist in several workplaces like tourist caves mainly because of the low ventilation rates existing at these enclosures. In this sense, in its 1990 publication, the ICRP recommended that high exposures of radon in workplace could be regarded as the responsibility of the operating management and should be considered as occupational exposure. In developed caves in which guides provide tours for the general public great care is needed for taking remedial actions concerning radon, because in some circumstances forced ventilation may alter the humidity inside the cave affecting the some of the formations or paintings that attract tourists. Tourist guides can work about 1900 hours per year, so the only option to protect them and other cave workers from radon exposure is to apply an appropriate system of radiation protection mainly based on limitation of exposure by restricting the amount of time spent in the cave. The information needed for carrying out the above mentioned protecting actions is related with the specific characteristics of the cave concerning the behaviour of radon and it decay products. In order to perform a precise effective dose calculation, factors like unattached progeny fraction (fp), equilibrium factor (F) and particle concentration (Z) are of main importance. One of the specific characteristic of the caves is the high unattached fraction due to very low particle concentration. The fp values can be higher than 0.1, for places with low ventilation and without additional aerosol sources, with Z -3 .In this work the results of the first stage of

  17. Analysis of the main factors affecting the evaluation of the dose in workplaces: the case of tourist caves

    Energy Technology Data Exchange (ETDEWEB)

    Sainz, C.; Santiago Quindos, L.; Fuente, I.; Nicolas, J.; Quindos, L. [Cantabria Univ., Dept. of Medical Physics. RADON Group, Faculty of Medicine, (Spain)

    2006-07-01

    Since 2001, Spanish law incorporated EURATOM basic standards for radiological protection, which include a request at the European Communities Member States to determine the working places on which exposure to natural radiation is significant. On Title VII (BOE 178/2001) radiation coming from natural sources has analogous role than radiation emitted from artificial ones used to. High concentrations of radon exist in several workplaces like tourist caves mainly because of the low ventilation rates existing at these enclosures. In this sense, in its 1990 publication, the ICRP recommended that high exposures of radon in workplace could be regarded as the responsibility of the operating management and should be considered as occupational exposure. In developed caves in which guides provide tours for the general public great care is needed for taking remedial actions concerning radon, because in some circumstances forced ventilation may alter the humidity inside the cave affecting the some of the formations or paintings that attract tourists. Tourist guides can work about 1900 hours per year, so the only option to protect them and other cave workers from radon exposure is to apply an appropriate system of radiation protection mainly based on limitation of exposure by restricting the amount of time spent in the cave. The information needed for carrying out the above mentioned protecting actions is related with the specific characteristics of the cave concerning the behaviour of radon and it decay products. In order to perform a precise effective dose calculation, factors like unattached progeny fraction (fp), equilibrium factor (F) and particle concentration (Z) are of main importance. One of the specific characteristic of the caves is the high unattached fraction due to very low particle concentration. The fp values can be higher than 0.1, for places with low ventilation and without additional aerosol sources, with Z < 4 103 particle cm{sup -3}.In this work the results

  18. Childhood adversity specificity and dose-response effect in non-affective first-episode psychosis.

    Science.gov (United States)

    Trauelsen, Anne Marie; Bendall, Sarah; Jansen, Jens Einar; Nielsen, Hanne-Grethe Lyse; Pedersen, Marlene Buch; Trier, Christopher Høier; Haahr, Ulrik H; Simonsen, Erik

    2015-06-01

    Reviews conclude that childhood and adolescence sexual, physical, emotional abuse and emotional and physical neglect are all risk factors for psychosis. However, studies suggest only some adversities are associated with psychosis. Dose-response effects of several adversities on risk of psychosis have not been consistently found. The current study aimed to explore adversity specificity and dose-response effects of adversities on risk of psychosis. Participants were 101 persons with first-episode psychosis (FEP) diagnosed with ICD-10 F20 - F29 (except F21) and 101 non-clinical control persons matched by gender, age and parents' socio-economic status. Assessment included the Childhood Trauma Questionnaire and parts of the Childhood Experience of Care and Abuse Questionnaire. Eighty-nine percent of the FEP group reported one or more adversities compared to 37% of the control group. Childhood and adolescent sexual, physical, emotional abuse, and physical and emotional neglect, separation and institutionalization were about four to 17 times higher for the FEP group (all p<0.01). The risk of psychosis increased two and a half times for each additional adversity. All associations between specific adversities and psychosis decreased when they were adjusted for other adversities. Our findings suggest that there is a large shared effect of adversities on the risk of psychosis. Contrary to the call for further research into specific adversities, we suggest a search for mechanisms in the shared effects of traumatization. Clinical implications are thorough assessment of adversities and their possible effects. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Effect of radiation doses rate on SOS response induction in irradiated Escherichia coli Cells

    International Nuclear Information System (INIS)

    Cuetara Lugo, Elizabeth B.; Fuentes Lorenzo, Jorge L.; Almeida Varela, Eliseo; Prieto Miranda, Enrique F.; Sanchez Lamar, Angel; Llagostera Casal, Montserrat

    2005-01-01

    The present work is aimed to study the effect of radiation dose rate on the induction of SOS response in Escherichia coli cells. We measured the induction of sul A reporter gene in PQ-37 (SOS Chromotest) cells. Lead devises were built with different diameter and these were used for diminishing the dose rate of PX- -30M irradiator. Our results show that radiation doses rate significantly modifies the induction of SOS response. Induction factor increases proportionally to doses rate in Escherichia coli cells defective to nucleotide excision repair (uvrA), but not in wild type cells. We conclude that the dose rate affects the level of induction of SOS response

  20. Dose planning and dose delivery in radiation therapy

    International Nuclear Information System (INIS)

    Knoeoes, T.

    1991-01-01

    A method has been developed for calibration of CT-numbers to volumetric electron density distributions using tissue substitutes of known elemental composition and experimentally determined electron density. This information have been used in a dose calculation method based on photon and electron interaction processes. The method utilizes a convolution integral between the photon fluence matrix and dose distribution kernels. Inhomogeneous media are accounted for using the theorems of Fano and O'Connor for scaling dose distribution kernels in proportion to electron density. For clinical application of a calculated dose plan, a method for prediction of accelerator output have been developed. The methods gives the number of monitor units that has to be given to obtain a certain absorbed dose to a point inside an irregular, inhomogeneous object. The method for verification of dose distributions outlined in this study makes it possible to exclude the treatment related variance contributions, making an objective evaluation of dose calculations with experiments feasible. The methods for electron density determination, dose calculation and prediction of accelerator output discussed in this study will all contribute to an increased accuracy in the mean absorbed dose to the target volume. However, a substantial gain in the accuracy for the spatial absorbed dose distribution will also follow, especially using CT for mapping of electron density together with the dose calculation algorithm. (au)

  1. Normal tissue dose-effect models in biological dose optimisation

    International Nuclear Information System (INIS)

    Alber, M.

    2008-01-01

    Sophisticated radiotherapy techniques like intensity modulated radiotherapy with photons and protons rely on numerical dose optimisation. The evaluation of normal tissue dose distributions that deviate significantly from the common clinical routine and also the mathematical expression of desirable properties of a dose distribution is difficult. In essence, a dose evaluation model for normal tissues has to express the tissue specific volume effect. A formalism of local dose effect measures is presented, which can be applied to serial and parallel responding tissues as well as target volumes and physical dose penalties. These models allow a transparent description of the volume effect and an efficient control over the optimum dose distribution. They can be linked to normal tissue complication probability models and the equivalent uniform dose concept. In clinical applications, they provide a means to standardize normal tissue doses in the face of inevitable anatomical differences between patients and a vastly increased freedom to shape the dose, without being overly limiting like sets of dose-volume constraints. (orig.)

  2. Technical basis for beta skin dose calculations at the Y-12 Plant

    International Nuclear Information System (INIS)

    Thomas, J.M.; Bogard, R.S.

    1994-03-01

    This report describes the methods for determining shallow dose equivalent to workers at the Oak Ridge Y-12 Plant from skin contamination detected by survey instrumentation. Included is a discussion of how the computer code VARSKIN is used to calculate beta skin dose and how the code input parameters affect skin dose calculation results. A summary of Y-12 Plant specific assumptions used in performing VARSKIN calculations is presented. Derivations of contamination levels that trigger the need for skin dose assessment are given for both enriched and depleted uranium with the use of Y-12 Plant site-specific survey instruments. Department of Energy recording requirements for nonuniform exposure of the skin are illustrated with sample calculations

  3. The interpretation of animal data in the calculation of doses from new radiolabeled compounds

    International Nuclear Information System (INIS)

    Naylor, G.P.L.; Ellender, M.; Harrison, J.D.

    1992-01-01

    At NRPB, dose calculations are performed for pharmaceutical companies wishing to obtain approval for human volunteer experiments. Animal data from one or more species are used to estimate the radiation doses to humans that would result from the administration of novel radiolabeled compounds. The calculations themselves are straightforward, but the animal data can be interpreted in different ways, leading to variations in the calculated dose. Doses to the gut compartments usually dominate the committed effective dose equivalent, but retention in other tissues may be important for some compounds. Long-term retention components in tissues can affect doses considerably, and the binding of many radiopharmaceuticals to melanin means that doses to the eye are particularly important. The effect of these considerations on calculating doses are considered, as well as the effect of changes in risk estimates and tissue weighting factors

  4. Uncertainties associated to the using of alanine/EPR for the dose interval in the radiotherapy; Incertezas associadas na utilizacao da alanina/RPE para o intervalo de dose da radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues Junior, O.; Campos, L. L. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2004-07-01

    The High Doses Laboratory of IPEN is developing a dosimetric system for high doses based on Electron Paramagnetic Resonance (EPR) of free radical radiation induced on alanine. The objective of this work is to present the efforts towards to improve the measure accuracy for doses in the range between 1-10 Gy. This system could be used as reference by radiotherapy services, as much in the quality control of the equipment, as for routine accompaniment of more complex handling where the total doses can reach some grays. The main problem for routine implantation is the calibration and the traceability of the system and many errors sources affects the accuracy of the measurements. In this work are discussed same aspects related on the uncertainty evaluation associated with high dose measurement using alanine and EPR. (author)

  5. Radiation Dose-Response Relationships and Risk Assessment

    International Nuclear Information System (INIS)

    Strom, Daniel J.

    2005-01-01

    The notion of a dose-response relationship was probably invented shortly after the discovery of poisons, the invention of alcoholic beverages, and the bringing of fire into a confined space in the forgotten depths of ancient prehistory. The amount of poison or medicine ingested can easily be observed to affect the behavior, health, or sickness outcome. Threshold effects, such as death, could be easily understood for intoxicants, medicine, and poisons. As Paracelsus (1493-1541), the 'father' of modern toxicology said, 'It is the dose that makes the poison.' Perhaps less obvious is the fact that implicit in such dose-response relationships is also the notion of dose rate. Usually, the dose is administered fairly acutely, in a single injection, pill, or swallow; a few puffs on a pipe; or a meal of eating or drinking. The same amount of intoxicants, medicine, or poisons administered over a week or month might have little or no observable effect. Thus, before the discovery of ionizing radiation in the late 19th century, toxicology ('the science of poisons') and pharmacology had deeply ingrained notions of dose-response relationships. This chapter demonstrates that the notion of a dose-response relationship for ionizing radiation is hopelessly simplistic from a scientific standpoint. While useful from a policy or regulatory standpoint, dose-response relationships cannot possibly convey enough information to describe the problem from a quantitative view of radiation biology, nor can they address societal values. Three sections of this chapter address the concepts, observations, and theories that contribute to the scientific input to the practice of managing risks from exposure to ionizing radiation. The presentation begins with irradiation regimes, followed by responses to high and low doses of ionizing radiation, and a discussion of how all of this can inform radiation risk management. The knowledge that is really needed for prediction of individual risk is presented

  6. Default Drug Doses in Anesthesia Information Management Systems.

    Science.gov (United States)

    Rodriquez, Luis I; Smaka, Todd J; Mahla, Michael; Epstein, Richard H

    2017-07-01

    In the United States, anesthesia information management systems (AIMS) are well established, especially within academic practices. Many hospitals are replacing their stand-alone AIMS during migration to an enterprise-wide electronic health record. This presents an opportunity to review choices made during the original implementation, based on actual usage. One area amenable to this informatics approach is the configuration in the AIMS of quick buttons for typical drug doses. The use of such short cuts, as opposed to manual typing of doses, simplifies and may improve the accuracy of drug documentation within the AIMS. We analyzed administration data from 3 different institutions, 2 of which had empirically configured default doses, and one in which defaults had not been set up. Our first hypothesis was that most (ie, >50%) of drugs would need at least one change to the existing defaults. Our second hypothesis was that for most (>50%) drugs, the 4 most common doses at the site lacking defaults would be included among the most common doses at the 2 sites with defaults. If true, this would suggest that having default doses did not affect the typical administration behavior of providers. The frequency distribution of doses for all drugs was determined, and the 4 most common doses representing at least 5% of total administrations for each drug were identified. The appropriateness of the current defaults was determined by the number of changes (0-4) required to match actual usage at the 2 hospitals with defaults. At the institution without defaults, the most frequent doses for the 20 most commonly administered drugs were compared with the default doses at the other institutions. At the 2 institutions with defaults, 84.7% and 77.5% of drugs required at least 1 change in the default drug doses (P default drug doses, 100% of the 20 most commonly administered doses (representing ≥5% of use for that drug) were included in the most commonly administered doses at the other 2

  7. Global DNA methylation responses to low dose radiation exposure

    International Nuclear Information System (INIS)

    Newman, M.R.; Ormsby, R.J.; Blyth, B.J.; Sykes, P.J.; Bezak, E.

    2011-01-01

    Full text: High radiation doses cause breaks in the DNA which are considered the critical lesions in initiation of radiation-induced cancer. However, at very low radiation doses relevant for the general public, the induction of such breaks will be rare, and other changes to the DNA such as DNA methylation which affects gene expression may playa role in radiation responses. We are studying global DNA methylation after low dose radiation exposure to determine if low dose radiation has short- and/or long-term effects on chromatin structure. We developed a sensitive high resolution melt assay to measure the levels of DNA methylation across the mouse genome by analysing a stretch of DNA sequence within Long Interspersed Nuclear Elements-I (LINE I) that comprise a very large proportion of the mouse and human genomes. Our initial results suggest no significant short-term or longterm) changes in global NA methylation after low dose whole-body X-radiation of 10 J1Gyor 10 mGy, with a significant transient increase in NA methylation observed I day after a high dose of I Gy. If the low radiation doses tested are inducing changes in bal DNA methylation, these would appear to be smaller than the variation observed between the sexes and following the general stress of the sham-irradiation procedure itself. This research was funded by the Low Dose Radiation Research Program, Biological and Environmental Research, US DOE, Grant DE-FG02-05ER64104 and MN is the recipient of the FMCF/BHP Dose Radiation Research Scholarship.

  8. Preservation of Minced Meats by Using Medium and High-doses Irradiation

    International Nuclear Information System (INIS)

    Hammad, A.A.I.; Swailam, H.M.H.; Taha, S.M.A.

    2003-01-01

    The effect of medium (2.5-10 kGy) dose irradiation and high(20-70 kGy) dose irradiation on the microbiological, chemical and organoleptic properties of minced meat samples was studied. It was found that irradiation dose of only 5 kGy greatly reduced all microbial counts and completely eliminated all non-spore forming pathogenic bacteria contaminated minced meat samples. Consequently this irradiation dose extended the refrigerated (3 degree ±1) storage life of these products for more than 8 weeks. This irradiation dose almost did not affect the chemical composition, particularly the main amino acids and main fatty acids of minced meat samples. Panelists could not differentiate between irradiated minced meat samples at this dose and unirradiated samples. High doses irradiation, i.e.40 and 70 kGy were sufficient and efficient in sterilization of minced meat samples and in obtaining long-stable minced meat products (Two years) at ambient temperature. These irradiation doses slightly reduced (not more than 7%) aspartic acid, glutamic acid, methionine and lysine of minced meat. It also decreased the relative percentage of total unsaturated fatty acids by not more than 17 % . These high irradiation doses caused loss of C 18:3 and C 20:1

  9. Dose Distributions of an 192Ir Brachytherapy Source in Different Media

    Directory of Open Access Journals (Sweden)

    C. H. Wu

    2014-01-01

    Full Text Available This study used MCNPX code to investigate the brachytherapy 192Ir dose distributions in water, bone, and lung tissue and performed radiophotoluminescent glass dosimeter measurements to verify the obtained MCNPX results. The results showed that the dose-rate constant, radial dose function, and anisotropy function in water were highly consistent with data in the literature. However, the lung dose near the source would be overestimated by up to 12%, if the lung tissue is assumed to be water, and, hence, if a tumor is located in the lung, the tumor dose will be overestimated, if the material density is not taken into consideration. In contrast, the lung dose far from the source would be underestimated by up to 30%. Radial dose functions were found to depend not only on the phantom size but also on the material density. The phantom size affects the radial dose function in bone more than those in the other tissues. On the other hand, the anisotropy function in lung tissue was not dependent on the radial distance. Our simulation results could represent valid clinical reference data and be used to improve the accuracy of the doses delivered during brachytherapy applied to patients with lung cancer.

  10. Electron microscopic studies of the matrix formation of hard tissue organized cell

    International Nuclear Information System (INIS)

    Chou, Ching-Eng

    1982-01-01

    In order to study the functions of odontoblast, especially on the matrix formation, odontoblasts of rats' incisor and molar teeth were used. The animals were sacrificed 5 minutes, 15 minutes, 30 minutes, 1 hour, 2 hours and 24 hours after 3 H-proline administration to obtain the specimen. The specimens were processed for electron microscopic autoradiography. The following results were obtained. 1. 5 minutes after 3 H-proline administration: Silver grains indicated 3 H-proline uptake were already noted within the cells and localized in the rough surfaced endoplasmic reticulum and surrounding ribosomes, partially within the karyoplasm. 2. 15 minutes after 3 H-proline administration: The number of silver grains were generally increased as compared with the findings obtained in 5 minutes. The localization moved to the Golgi apparatus and their surroundings. 3. 30 minutes after 3 H-proline administration: Silver grains obtained in Tome's fibers area and some in predentin. In this area granules derived from Golgi body were found. 4. 1 hour after 3 H-proline administration: The number of silver grains were generally decreased and more pronounced movement toward predentin, the marked movement of silver grains were obtained onto the collagen fibers and surroundings. 5. 2 hours after 3 H-proline administration: Silver grains moved to the calcified area and there collagen fibers became more remarkable. 6. 24 hours after 3 H-proline administration: No silver grains were founded in the odontoblast side but deposited in the predentin calcified area with stable condition. Based on the results of these observations, odontoblasts were shown to perform the function of synthesis, storage, transportation and control of collagen formation in addition to the role of matrix formation. (author)

  11. Sub-Lethal Dose of Shiga toxin 2 from Enterohemorrhagic Escherichia coli Affects Balance and Cerebellar Cythoarquitecture.

    Directory of Open Access Journals (Sweden)

    Luciana eD’Alessio

    2016-02-01

    Full Text Available Shiga toxin producing Escherichia coli may damage the central nervous system before or concomitantly to manifested hemolytic uremic syndrome symptoms. The cerebellum is frequently damaged during this syndrome, however the deleterious effects of Shiga toxin 2 has never been integrally reported by ultrastructural, physiological and behavioral means. The aim of this study was to determine the cerebellar compromise after intravenous administration of a sub-lethal dose of Shiga toxin 2 by measuring the cerebellar blood brain barrier permeability, behavioral task of cerebellar functionality (inclined plane test, and ultrastructural analysis (transmission electron microscope. Intravenous administration of vehicle (control group, sub-lethal dose of 0.5 ηg and 1 ηg of Stx2 per mouse were tested for behavioral and ultrastructural studies. A set of three independent experiments were performed for each study (n=6. Blood–Brain Barrier resulted damaged and consequently its permeability was significantly increased. Lower scores obtained in the inclined plane task denoted poor cerebellar functionality in comparison to their controls. The most significant lower score was obtained after 5 days of 1ηg of toxin administration. Transmission electron microscope micrographs from the Stx2-treated groups showed neurons with a progressive neurodegenerative condition in a dose dependent manner. As sub-lethal intravenous Shiga toxin 2 altered the blood brain barrier permeability in the cerebellum the toxin penetrated the cerebellar parenchyma and produced cell damaged with significant functional implications in the test balance.

  12. Rural areas affected by the Chernobyl accident: Radiation exposure and remediation strategies

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, P., E-mail: Jacob@helmholtz-muenchen.de [Helmholtz Zentrum Muenchen, Institute of Radiation Protection, 85764 Neuherberg (Germany); Fesenko, S. [International Atomic Energy Agency, Vienna (Austria); Bogdevitch, I. [Scientific Research State Enterprise ' Institute for Soil Science and Agrochemistry' , Minsk (Belarus); Kashparov, V. [Ukrainian Institute of Agricultural Radiology, Chabany (Ukraine); Sanzharova, N. [Russian Institute of Agricultural Radiology and Radioecology, Obninsk (Russian Federation); Grebenshikova, N. [Institute of Radiology, Gomel (Belarus); Isamov, N. [Russian Institute of Agricultural Radiology and Radioecology, Obninsk (Russian Federation); Lazarev, N. [Ukrainian Institute of Agricultural Radiology, Chabany (Ukraine); Panov, A. [Russian Institute of Agricultural Radiology and Radioecology, Obninsk (Russian Federation); Ulanovsky, A. [Helmholtz Zentrum Muenchen, Institute of Radiation Protection, 85764 Neuherberg (Germany); Zhuchenko, Y. [Institute of Radiology, Gomel (Belarus); Zhurba, M. [Ukrainian Institute of Agricultural Radiology, Chabany (Ukraine)

    2009-12-15

    Main objectives of the present work were to develop an internationally agreed methodology for deriving optimized remediation strategies in rural areas that are still affected by the Chernobyl accident, and to give an overview of the radiological situation in the three affected countries, Belarus, Russia and Ukraine. Study settlements were defined by having in 2004 less than 10,000 inhabitants and official dose estimates exceeding 1 mSv. Data on population, current farming practices, contamination of soils and foodstuffs, and remedial actions previously applied were collected for each of such 541 study settlements. Calculations of the annual effective dose from internal radiation were validated with extensive data sets on whole body counter measurements. According to our calculations for 2004, in 290 of the study settlements the effective dose exceeded 1 mSv, and the collective dose in these settlements amounted to about 66 person-Sv. Six remedial actions were considered: radical improvement of grassland, application of ferrocyn to cows, feeding pigs with uncontaminated fodder before slaughter, application of mineral fertilizers for potato fields, information campaign on contaminated forest produce, and replacement of contaminated soil in populated areas by uncontaminated soil. Side effects of the remedial actions were quantified by a 'degree of acceptability'. Results are presented for two remediation strategies, namely, Strategy 1, in which the degree of acceptability was given a priority, and Remediation Strategy 2, in which remedial actions were chosen according to lowest costs per averted dose only. Results are highly country-specific varying from preference for soil replacement in populated areas in Belarus to preference for application of ferrocyn to cows in Ukraine. Remedial actions in 2010 can avert a large collective dose of about 150 person-Sv (including averted doses, which would be received in the following years). Nevertheless, the number of

  13. Low dose X-irradiation of thymus filler cells in limiting dilution cultures of LPS-reactive B cells reduces the background Ig-secreting cells without affecting growth-supporting capacity

    International Nuclear Information System (INIS)

    Hooijkaas, H.; Preesman, A.A.; Benner, R.

    1982-01-01

    Frequencies of lipopolysaccharide (LPS)-reactive B cells in the mouse can be determined in the limiting dilution culture system developed by Andersson et al. (1976, 1977) which is completely dependent upon the presence of thymus filler cells, usually of rat origin. The assessment of B cell clones of mouse origin, however, can be hampered by the occurrence of varying numbers of thymus-derived immunoglobulin (Ig)-secreting cells. The number of these background Ig-secreting cells can be significantly reduced by low dose (110 mgray = 11 rad) X-irradiation of the rat thymus filler cells, without affecting their growth-supporting capacity. (Auth.)

  14. Dose optimization in radiotherapy patients for IMRT based on 4D-CBCT

    International Nuclear Information System (INIS)

    Alfonso, R.; Castillo, D.; Ascensión, Y.; Linares, H.; García, F.; Argota, R.

    2015-01-01

    The use of tomographic systems based on conical photon beams kVp (kV-CBCT) to verify the accuracy of the positioning of patients in external radiotherapy treatments has expanded in recent years, with increasing availability of linear accelerators systems for image guided radiation therapy (IGRT) based kV-CBCT systems, incorporated into the gantry of the equipment. Several studies have evaluated the collateral doses received by patients using these positioning systems for radiotherapy (RT). Recently, the firm Elekta has developed a solution to manage the effects of respiratory movements and reduce internal margins that affect the planning target volume (Symmetry TM ), which is based on the acquisition of dynamic tomographic studies (4D- CBCT), making it possible to estimate the average white temporal position in each treatment, without using methods triggered or ‘tracking’. These 4D studies however require a greater number of images per gantry angle, potentially involves a higher dose administered to patients, besides the actual dose treatment beam. The present study investigated a methodology to assess dose rates 4DCBCT (4D-CBDI) using dosimetric instrumentation and phantoms as those typically available in radiotherapy departments. The doses received by different techniques are compared using as criteria of merit image quality and overall geometric accuracy achieved in positioning and internal margins. The results show that it is possible to reduce the administered to patients in studies of CBCT static and dynamic, without significantly affecting the objectives of the same in terms of geometric accuracy dose. [es

  15. A C-terminal fragment of fibulin-7 interacts with endothelial cells and inhibits their tube formation in culture.

    Science.gov (United States)

    de Vega, Susana; Suzuki, Nobuharu; Nonaka, Risa; Sasaki, Takako; Forcinito, Patricia; Arikawa-Hirasawa, Eri; Yamada, Yoshihiko

    2014-03-01

    We have previously demonstrated that fibulin-7 (Fbln7) is expressed in teeth by pre-odontoblast and odontoblast cells, localized in the basement membrane and dentin matrices, and is an adhesion molecule for dental mesenchyme cells and odontoblasts. Fbln7 is also expressed in blood vessels by endothelial cells. In this report, we show that a recombinant C-terminal Fbln7 fragment (Fbln7-C) bound to Human Umbilical Vein Endothelial Cells (HUVECs) but did not promote cell spreading and actin stress fiber formation. Fbln7-C binding to HUVECs induced integrin clustering at cell adhesion sites with other focal adhesion molecules, and sustained activation of FAK, p130Cas, and Rac1. In addition, RhoA activation was inhibited, thereby preventing HUVEC spreading. As endothelial cell spreading is an important step for angiogenesis, we examined the effect of Fbln7-C on angiogenesis using in vitro assays for endothelial cell tube formation and vessel sprouting from aortic rings. We found that Fbln7-C inhibited the HUVEC tube formation and the vessel sprouting in aortic ring assays. Our findings suggest potential anti-angiogenic activity of the Fbln7 C-terminal region. Published by Elsevier Inc.

  16. Rac1 Regulates the Proliferation, Adhesion, Migration, and Differentiation of MDPC-23 Cells.

    Science.gov (United States)

    Ren, Jing; Liang, Guobin; Gong, Li; Guo, Bing; Jiang, Hongwei

    2017-04-01

    Stem cells are responsible for replacing damaged pulp tissue; therefore, promoting their survival and inducing their adhesion to dentin are vital. As a member of the Rho family of guanosine triphosphatases, Rac1 is an important regulator of osteoblast functions. However, little is known about its role in regenerative endodontic procedures. The current study examined the role of Rac1 in the proliferation, migration, and odontoblastic differentiation of MDPC-23 cells. MDPC-23 cells were transfected with small interfering RNA to knock down Rac1 expression, and then their proliferation, migration, adhesion, and odontoblastic differentiation were examined in vitro. MDPC-23 cells transfected with si-Rac1 exhibited the increased expression of several key odontogenic protein markers, including Dmp1, Dspp, Runx2, and alkaline phosphatase, as well as decreased proliferation and migration in vitro. The results suggest that Rac1 might regulate nuclear factor kappa B signaling in MDPC-23 cells. Rac1 may have vital roles in the proliferation, migration, adhesion, and odontoblastic differentiation of MDPC-23 cells. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  17. Different expressions of connexin 43 and 32 in the fibroblasts of human dental pulp.

    Science.gov (United States)

    Ibuki, N; Yamaoka, Y; Sawa, Y; Kawasaki, T; Yoshida, S

    2002-06-01

    The expression and localization of gap junctional proteins connexin (Cx) 26, 32, and 43 was examined in human dental pulp. Dental pulp tissues were obtained from human third molars immediately after extraction. Some pulp tissues were used for cell culture, and the rest for histological observations. Immunostaining for cultured dental pulp fibroblasts (DPFs) showed that Cx32 and 43 were expressed in human DPFs, and proteins corresponding to 27 (Cx32) and 43kDa (Cx43) were identified by Western blot analysis. Immunostaining for tissue sections showed that the expression of Cx32 and 43 was observed in the entire region of the pulp and further strong expression of Cx32 was established beneath the cell-rich zone. Considering the close relationship between Cx types and cell functions, the results indicate that DPFs beneath the cell-rich zone may have specific, Cx32-related functions. The cell rich zone is thought to contain progenitor odontoblasts that can be induced to differentiate into mature odontoblasts in response to wounding. Therefore, it may be hypothesized that DPFs just beneath the cell-rich zone produce proteins and induce odontoblast differentiation from the cells in the cell-rich zone.

  18. Personal dosimetry statistics and specifics of low dose evaluation

    International Nuclear Information System (INIS)

    Avila, R.E.; Gómez Salinas, R.A.; Oyarzún Cortés, C.H.

    2015-01-01

    The dose statistics of a personal dosimetry service, considering 35,000+ readings, display a sharp peak at low dose (below 0.5 mSv) with skewness to higher values. A measure of the dispersion is that approximately 65% of the doses fall below the average plus 2 standard deviations, an observation which may prove helpful to radiation protection agencies. Categorizing the doses by the concomitant use of a finger ring dosimeter, that skewness is larger in the whole body, and ring dosimeters. The use of Harshaw 5500 readers at high gain leads to frequent values of the glow curve that are judged to be spurious, i.e. values not belonging to the roughly normal noise over the curve. A statistical criterion is shown for identifying those anomalous values, and replacing them with the local behavior, as fit by a cubic polynomial. As a result, the doses above 0.05 mSv which are affected by more than 2% comprise over 10% of the data base. The low dose peak of the statistics, above, has focused our attention on the evaluation of LiF(Mg,Ti) dosimeters exposed at low dose, and read with Harshaw 5500 readers. The standard linear procedure, via an overall reader calibration factor, is observed to fail at low dose, in detailed calibrations from 0.02 mSv to 1 Sv. A significant improvement is achieved by a piecewise polynomials calibration curve. A cubic, at low dose is matched, at ∼10 mSv, in value and first derivative, to a linear dependence at higher doses. This improvement is particularly noticeable below 2 mSv, where over 60% of the evaluated dosimeters are found. (author)

  19. The limiting dose rate and its importance in radiation protection

    International Nuclear Information System (INIS)

    Bakkiam, D.; Sonwani, Swetha; Arul Ananthakumar, A.; Mohankumar, Mary N.

    2012-01-01

    The concept of defining a low dose of ionizing radiation still remains unclear. Before attempting to define a low dose, it is more important to define a low-dose rate since effects at low dose-rates are different from those observed at higher dose-rates. Hence, it follows that low dose-rates rather than a low dose is an important criteria to determine radio-biological effects and risk factors i.e. stochastic health effects. Chromosomal aberrations induced by ionizing radiations are well fitted by quadratic model Y= áD + âD 2 + C with the linear coefficient of dose predominating for high LET radiations and low doses of low LET. At higher doses and dose rates of sparsely ionizing radiation, break pairs produced by inter-track action leads to the formation of exchange type aberrations and is dependent on dose rate. Whereas at lower doses and dose rates, intra-track action produces break pairs and resulting aberrations are in direct proportion to absorbed dose and independent of dose rate. The dose rate at which inter-track ceases to be observable and where intra-track action effectively becomes the sole contributor of lesion-pair formation is referred to as limiting dose rate (LDR). Once the LDR is reached further reduction in dose rates will not affect the slope of DR since breaks produced by independent charged particle tracks are widely separated in time to interact with each other for aberration yield. This linear dependency is also noticed for acute exposures at very low doses. Existing reports emphasizes the existence of LDR likely to be e6.3cGyh -1 . However no systematic studies have been conducted so far to determine LDR. In the present investigation DR curves were constructed for the dose rates 0.002 and 0.003 Gy/min and to define LDR at which a coefficient approaches zero. Extrapolation of limiting low dose rate data can be used to predict low dose effects regardless of dose rate and its definition ought to serve as a useful index for studies pertaining

  20. Dose optimisation of double-contrast barium enema examinations.

    Science.gov (United States)

    Berner, K; Båth, M; Jonasson, P; Cappelen-Smith, J; Fogelstam, P; Söderberg, J

    2010-01-01

    The purpose of the present work was to optimise the filtration and dose setting for double-contrast barium enema examinations using a Philips MultiDiagnost Eleva FD system. A phantom study was performed prior to a patient study. A CDRAD phantom was used in a study where copper and aluminium filtration, different detector doses and tube potentials were examined. The image quality was evaluated using the software CDRAD Analyser and the phantom dose was determined using the Monte Carlo-based software PCXMC. The original setting [100 % detector dose (660 nGy air kerma) and a total filtration of 3.5 mm Al, at 81 kVp] and two other settings identified by the phantom study (100 % detector dose and additional filtration of 1 mm Al and 0.2 mm Cu as well as 80 % detector dose and added filtration of 1 mm Al and 0.2 mm Cu) were included in the patient study. The patient study included 60 patients and up to 8 images from each patient. Six radiologists performed a visual grading characteristics study to evaluate the image quality. A four-step scale was used to judge the fulfillment of three image quality criteria. No overall statistical significant difference in image quality was found between the three settings (P > 0.05). The decrease in the effective dose for the settings in the patient study was 15 % when filtration was added and 34 % when both filtrations was added and detector dose was reduced. The study indicates that additional filtration of 1 mm Al and 0.2 mm Cu and a decrease in detector dose by 20 % from the original setting can be used in colon examinations with Philips MultiDiagnost Eleva FD to reduce the patient dose by 30 % without significantly affecting the image quality. For 20 exposures, this corresponds to a decrease in the effective dose from 1.6 to 1.1 mSv.

  1. Analysis of the main factors affecting the evaluation of the radon dose in workplaces: The case of tourist caves

    International Nuclear Information System (INIS)

    Sainz, Carlos; Quindos, Luis Santiago; Fuente, Ismael; Nicolas, Jorge; Quindos, Luis

    2007-01-01

    High concentrations of radon exist in several workplaces like tourist caves mainly because of the low ventilation rates existing at these enclosures. In this sense, in its 1990 publication, the ICRP recommended that high exposures of radon in workplaces should be considered as occupational exposure. In developed caves in which guides provide tours for the general public great care is needed for taking remedial actions concerning radon, because in some circumstances forced ventilation may alter the humidity inside the cave affecting some of the formations or paintings that attract tourists. Tourist guides can work about 1900 h per year, so the only option to protect them and other cave workers from radon exposure is to apply an appropriate system of radiation protection mainly based on limitation of exposure by restricting the amount of time spent in the cave. Because of the typical environmental conditions inside the caves, the application of these protecting actions requires to know some indoor air characteristics like particle concentration, as well as radon progeny behaviour in order to get more realistic effective dose values In this work the results of the first two set of radon measurements program carried out in 10 caves located in the region of Cantabria (Spain) are presented

  2. Biosynthesis of phenolic compounds and water soluble vitamins in culantro (Eryngium foetidum L. plantlets as affected by low doses of gamma irradiation

    Directory of Open Access Journals (Sweden)

    Amina Abd El-Hamid ALY

    2010-11-01

    Full Text Available Explants obtained from in-vitro propagated plantlets of Culantro (Eryngium foetidum L. were exposed to four dose levels of γ-irradiation (0.0, 10.0, 20.0 and 40.0 Gy to investigate the biosynthesis of phenolic compounds and water soluble vitamins in Culantro fresh plantlets. Among six identified phenolic compounds, the content of p-cumaric acid was the highest in the extracts, followed by caffeic acid, coumarin, benzoic acid, salicylic acid and apigenin. Significant increases were observed at dose 40.0 Gy (61.66 mg/g d.w. for flavonoids, 18.02 mg/g d.w, for flavonone and 5.06 mg/g d.w for anthocyanin compared to control. On the other hand, the flavonols were decreased by increasing the irradiation dose. Vitamin C was increased in irradiated samples and this increase was in correlation with irradiation dose level. Thiamin, riboflavin and nicotinic acid were enhanced by the applied dose level 10 Gy. In addition, folic acid was enhanced by the dose levels 20 and 40 Gy and not detected for the control and 10 Gy treatments. Meanwhile, pyridoxine was decreased by increasing the irradiation dose level. The results obtained suggested that both low doses of γ-irradiation and tissue culture technique could be used to produce plantlets with high amount of phenolic compounds and water soluble vitamins.

  3. Chromosomal Aberrations in Normal and AT Cells Exposed to High Dose of Low Dose Rate Irradiation

    Science.gov (United States)

    Kawata, T.; Shigematsu, N.; Kawaguchi, O.; Liu, C.; Furusawa, Y.; Hirayama, R.; George, K.; Cucinotta, F.

    2011-01-01

    Ataxia telangiectasia (A-T) is a human autosomally recessive syndrome characterized by cerebellar ataxia, telangiectases, immune dysfunction, and genomic instability, and high rate of cancer incidence. A-T cell lines are abnormally sensitive to agents that induce DNA double strand breaks, including ionizing radiation. The diverse clinical features in individuals affected by A-T and the complex cellular phenotypes are all linked to the functional inactivation of a single gene (AT mutated). It is well known that cells deficient in ATM show increased yields of both simple and complex chromosomal aberrations after high-dose-rate irradiation, but, less is known on how cells respond to low-dose-rate irradiation. It has been shown that AT cells contain a large number of unrejoined breaks after both low-dose-rate irradiation and high-dose-rate irradiation, however sensitivity for chromosomal aberrations at low-dose-rate are less often studied. To study how AT cells respond to low-dose-rate irradiation, we exposed confluent normal and AT fibroblast cells to up to 3 Gy of gamma-irradiation at a dose rate of 0.5 Gy/day and analyzed chromosomal aberrations in G0 using fusion PCC (Premature Chromosomal Condensation) technique. Giemsa staining showed that 1 Gy induces around 0.36 unrejoined fragments per cell in normal cells and around 1.35 fragments in AT cells, whereas 3Gy induces around 0.65 fragments in normal cells and around 3.3 fragments in AT cells. This result indicates that AT cells can rejoin breaks less effectively in G0 phase of the cell cycle? compared to normal cells. We also analyzed chromosomal exchanges in normal and AT cells after exposure to 3 Gy of low-dose-rate rays using a combination of G0 PCC and FISH techniques. Misrejoining was detected in the AT cells only? When cells irradiated with 3 Gy were subcultured and G2 chromosomal aberrations were analyzed using calyculin-A induced PCC technique, the yield of unrejoined breaks decreased in both normal and AT

  4. Qualidade do fruto de melão rendilhado em função de doses de nitrogênio Muskmelon fruit quality as affected by nitrogen rates

    Directory of Open Access Journals (Sweden)

    Evando Luiz Coelho

    2003-01-01

    Full Text Available Foram realizados dois experimentos com meloeiro, (Cucumis melo L. Grupo Cantalupensis, no verão, em condições de campo e de ambiente protegido com o objetivo de avaliar o efeito de doses de nitrogênio sobre características físicas (massa, diâmetro, espessura da polpa e diâmetro da cavidade e químicas (teor de sólidos solúveis, acidez titulável e pH do fruto. Cada experimento constou de quatro blocos ao acaso, contendo cinco tratamentos que foram as doses de nitrogênio (0, 75, 150, 300 e 450 kg ha-1de N. Utilizou-se uréia, sendo 30% colocada nos sulcos, antes do transplante, e 70% remanescente aplicada via água de irrigação, por gotejamento, durante o ciclo da cultura. Nos dois ambientes, os valores das características físicas elevaram-se com o aumento da dose de N. Sob ambiente protegido, associados à dose de 312 kg.ha-1de N, que propiciou a produção comercial máxima de frutos (PCM, os valores de massa, diâmetro, espessura da polpa e cavidade do fruto foram: 1.280 g, 12,6 cm, 3,1 cm e 6,1 cm respectivamente. No campo, com dose de 344 kg.ha-1de N, que propiciou a PCM, os valores correspondentes foram de 1.390 g, 13,1 cm, 3,4 cm e 5,9 cm respectivamente. O teor de sólidos solúveis não foi influenciado por doses de N, alcançando 9% e 9,5%, respectivamente, nos frutos produzidos no ambiente protegido e no campo. Nos dois ambientes, a acidez titulável da polpa elevou-se com as doses de N, atingindo 0,13 e 0,14 % de ácido cítrico com as doses de N para a PCM. O pH do fruto produzido em ambiente protegido não foi influenciado pelo aumento da dose de N, atingindo 6,83, enquanto o pH daquele produzido no campo elevou-se com as doses de N, atingindo 6,99 com a dose de N para a PCM.Two experiments with melon plants (Cucumis melo L. Cantalupensis Group were carried out in the summer, in the field and in an unheated greenhouse, aiming to evaluate the effect of nitrogen rates on fruit physical (weight, diameter, flesh pulp

  5. Dose and dose rate monitor

    International Nuclear Information System (INIS)

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

    1984-10-01

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

  6. How accurately can the peak skin dose in fluoroscopy be determined using indirect dose metrics?

    International Nuclear Information System (INIS)

    Jones, A. Kyle; Ensor, Joe E.; Pasciak, Alexander S.

    2014-01-01

    Purpose: Skin dosimetry is important for fluoroscopically-guided interventions, as peak skin doses (PSD) that result in skin reactions can be reached during these procedures. There is no consensus as to whether or not indirect skin dosimetry is sufficiently accurate for fluoroscopically-guided interventions. However, measuring PSD with film is difficult and the decision to do so must be madea priori. The purpose of this study was to assess the accuracy of different types of indirect dose estimates and to determine if PSD can be calculated within ±50% using indirect dose metrics for embolization procedures. Methods: PSD were measured directly using radiochromic film for 41 consecutive embolization procedures at two sites. Indirect dose metrics from the procedures were collected, including reference air kerma. Four different estimates of PSD were calculated from the indirect dose metrics and compared along with reference air kerma to the measured PSD for each case. The four indirect estimates included a standard calculation method, the use of detailed information from the radiation dose structured report, and two simplified calculation methods based on the standard method. Indirect dosimetry results were compared with direct measurements, including an analysis of uncertainty associated with film dosimetry. Factors affecting the accuracy of the different indirect estimates were examined. Results: When using the standard calculation method, calculated PSD were within ±35% for all 41 procedures studied. Calculated PSD were within ±50% for a simplified method using a single source-to-patient distance for all calculations. Reference air kerma was within ±50% for all but one procedure. Cases for which reference air kerma or calculated PSD exhibited large (±35%) differences from the measured PSD were analyzed, and two main causative factors were identified: unusually small or large source-to-patient distances and large contributions to reference air kerma from cone

  7. Determination of organ doses and effective doses in radiooncology

    International Nuclear Information System (INIS)

    Roth, J.; Martinez, A.E.

    2007-01-01

    Background and Purpose: With an increasing chance of success in radiooncology, it is necessary to estimate the risk from radiation scatter to areas outside the target volume. The cancer risk from a radiation treatment can be estimated from the organ doses, allowing a somewhat limited effective dose to be estimated and compared. Material and Methods: The doses of the radiation-sensitive organs outside the target volume can be estimated with the aid of the PC program PERIDOSE developed by van der Giessen. The effective doses are determined according to the concept of ICRP, whereby the target volume and the associated organs related to it are not taken into consideration. Results: Organ doses outside the target volume are generally < 1% of the dose in the target volume. In some cases, however, they can be as high as 3%. The effective doses during radiotherapy are between 60 and 900 mSv, depending upon the specific target volume, the applied treatment technique, and the given dose in the ICRU point. Conclusion: For the estimation of the radiation risk, organ doses in radiooncology can be calculated with the aid of the PC program PERIDOSE. While evaluating the radiation risk after ICRP, for the calculation of the effective dose, the advanced age of many patients has to be considered to prevent that, e.g., the high gonad doses do not overestimate the effective dose. (orig.)

  8. Vaxchora: A Single-Dose Oral Cholera Vaccine.

    Science.gov (United States)

    Cabrera, Adriana; Lepage, Jayne E; Sullivan, Karyn M; Seed, Sheila M

    2017-07-01

    To review trials evaluating the efficacy and safety of Vaxchora, a reformulated, single-dose, oral, lyophilized Vibrio cholerae CVD 103-HgR vaccine for the prevention of travel-related cholera caused by V cholerae serogroup O1. A literature search was conducted using MEDLINE (1946 to January week 3, 2017) and EMBASE (1996 to 2017 week 3). Keywords included oral cholera vaccine, single-dose, Vaxchora, and CVD 103-HgR. Limits included human, clinical trials published in English since 2010. ClinicalTrials.gov was used as a source for unpublished data. Additional data sources were obtained through bibliographic review of selected articles. Studies that addressed the safety and efficacy of Vaxchora, the reformulated, single-dose oral CVD 103-HgR cholera vaccine, were selected for analysis. Approval of Vaxchora, was based on efficacy of the vaccine in human trials demonstrating 90.3% protection among those challenged with V cholerae 10 days after vaccination and in immunogenicity studies with 90% systemic vibriocidal antibody conversion at 6 months after a single-dose of vaccine. Tolerability was acceptable, with the most common adverse effects reported to be fatigue, headache, and abdominal pain. Vaxchora is the only FDA-approved, single-dose oral vaccine for the prevention of cholera caused by V cholerae serogroup O1 in adult travelers from the United States going to cholera-affected areas. Safety and efficacy has not been established in children, immunocompromised persons, and pregnant or breastfeeding women or those living in cholera-endemic areas.

  9. SSD effects on high energy x-ray surface and build up dose

    International Nuclear Information System (INIS)

    Cheung, T.; Yu, P.K.N.; Butson, M.J.; Cancer Services, Wollongong, NSW

    2004-01-01

    Full text: Dose in the build up region for high energy x-rays produced by a medical linear accelerator is affected by the x-ray source to patient surface distance (SSD). The use of isocentric treatments whereby the tumour is positions 100cm from the source means that depending of the depth of the tumour and the size of the patient, the SSD can vary from distances of 80cm to 100cm. To achieve larger field sizes, the SSD can also be extended out to 120cm at times. Results have shown that open fields are not significantly affected by SSD changes with deviations in percentage dose being less than 4% of maximum dose for SSD's from 80cm to 120cm SSD. With the introduction of beam modifying devices such as Perspex blocking trays, the effects are significant with a deviation of up to 22% measured at 6MV energy with a 6mm Perspex tray for SSD's from 80cm to 120cm. These variations are largest at the skin surface and reduce with depth. The use of a multi leaf collimator for blocking removes extra skin dose caused by the Perspex block trays with decreasing SSD. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

  10. The dose from actinides in the environment

    International Nuclear Information System (INIS)

    Harley, Naomi H.; Pasternack, Bernard S.

    1978-01-01

    We attempt to evaluate the health effects on local populations from the nuclear power industry. The nuclides which are thought to be most hazardous are the long-lived, alpha-emitting isotopes of plutonium, americium and curium. These long-lived alpha emitters will almost certainly be dispersed in the environment during fuel reprocessing. Their effect is local, not global and at worst a single community could be affected. The most important pathway for exposure to the actinides is through inhalation following resuspension of contaminated soil particles. The most important alpha dose estimates are to cells in bronchial epithelium and cells on bone surfaces. These alpha dose estimates are calculated for a dispersal which contaminates soil with 1 pCi/g of each of the nuclides Pu 238,239 , Am 241 , Cm 242,244 . These bronchial and bone cell dose estimates are compared with those from the naturally occurring actinide 232 Th (and daughters) which are normally found in soil at a level of about 1 pCi/g. (author)

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

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  12. Maltese CT doses for commonly performed examinations demonstrate alignment with published DRLs across europe

    International Nuclear Information System (INIS)

    Zarb, F.; McEntee, M.; Rainford, L.

    2012-01-01

    This work recommends dose reference levels (DRLs) for abdomen, chest and head computerised tomography (CT) examinations in Malta as the first step towards national CT dose optimisation. Third quartiles volume CT dose index values for abdomen: 12.1 mGy, chest: 13.1 mGy and head: 41 mGy and third quartile dose-length product values for abdomen: 539.4, chest: 492 and head: 736 mGy cm -1 are recommended as Maltese DRLs derived from this first Maltese CT dose survey. These values compare well with DRLs of other European countries indicating that CT scanning in Malta is consistent with standards of good practice. Further work to minimise dose without affecting image quality and extending the establishment of DRLs for other CT examinations is recommended. (authors)

  13. Radiation chemistry of water at low dose rates with emphasis on the energy balance

    International Nuclear Information System (INIS)

    Fletcher, J.W.

    1982-09-01

    There has been considerable interest in absorbed dose water calorimetry. In order to accurately relate the temperature change to the absorbed dose, the energy balance of the overall chemistry of the system must be known. The radiolytic products and their yields are affected by dose rate, dose and added solutes. The yields of the radiolytic products have been calculated using a computer program developed at Atomic Energy of Canada. The chemical energy balance was determined as a function of dose for various dose rates and initial concentrations of hydrogen (H 2 ), oxygen (O 2 ), and hydrogen peroxide (H 2 O 2 ). In solutions containing H 2 O 2 or O 2 and H 2 the chemical reactions were exothermic; in other cases they were endothermic. Approach to equilibrium and equilbrium conditions are discussed

  14. Electronic Personal Dosimeters Open a New Dimension in Radon Dose Management

    International Nuclear Information System (INIS)

    Streil, T.; Oeser, V.

    2001-01-01

    Full text: Electronic Radon dosimeters enable the installation of completely automated dose management systems in Radon exposed areas for the first time. In opposition to passive dosimeters, the actual dose value will be displayed online. The alarm function indicates the reaching of the permissible doses and prevents exceeding of given levels. The immediate availability of all user- and measurement information leads to a new level of quality assurance within complex dose management systems. Furthermore, the sequentially stored data give an exact assignment of concentration and dose values to the real time and location. This information is very important for staff planning and the assessment of Radon affected objects (local dosimeters). The measurement of Radon concentration is based on the alpha spectroscopy. The gas diffuses through a membrane into the measurement chamber. Progeny inside the chamber ionised after decay will be collected at the detector surface forced by the electric field. All incoming events will be processed by a Multi Channel Analyser (MCA). A integral spectrum and a record of five peak-areas (each assigned to a single nuclide) at every time step will be stored for computing concentration and dose values. The sensitivity of the device was determined to 0.25 counts/(minkBq/m 3 ). An average concentration of 200 Bq/m 3 during an eight-hours work day gives an error of ±20%. The response time (95% of final value) only depends on half live times of 218 Po and 214 Po (10 minutes using fast mode, 2 hours in slow mode) and is not affected by the diffusion membrane. Further tests at high levels (up to several MBq/m 3 ) were carried out successfully during soil gas and water measurements. (author)

  15. Optimized Dose Distribution of Gammamed Plus Vaginal Cylinders

    International Nuclear Information System (INIS)

    Supe, Sanjay S.; Bijina, T.K.; Varatharaj, C.; Shwetha, B.; Arunkumar, T.; Sathiyan, S.; Ganesh, K.M.; Ravikumar, M.

    2009-01-01

    points were higher for the apex model compared with the non-apex model. Mean doses to the optimization points for both the cylinder models and all the cylinder diameters were 6 Gy, matching with the prescription dose of 6 Gy. Iterative optimization routine resulted in the highest dose to apex point and dome points. The mean dose for optimization point was 6.01 Gy for iterative optimization and was much higher than 5.74 Gy for geometric and equal times routines. Step size of 1 cm gave the highest dose to the apex point. This step size was superior in terms of mean dose to optimization points. Selection of dose optimization points for the derivation of optimized dose distributions for vaginal cylinders affects the dose distributions

  16. Single toxin dose-response models revisited

    Energy Technology Data Exchange (ETDEWEB)

    Demidenko, Eugene, E-mail: eugened@dartmouth.edu [Department of Biomedical Data Science, Geisel School of Medicine at Dartmouth, Hanover, NH03756 (United States); Glaholt, SP, E-mail: sglaholt@indiana.edu [Indiana University, School of Public & Environmental Affairs, Bloomington, IN47405 (United States); Department of Biological Sciences, Dartmouth College, Hanover, NH03755 (United States); Kyker-Snowman, E, E-mail: ek2002@wildcats.unh.edu [Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH03824 (United States); Shaw, JR, E-mail: joeshaw@indiana.edu [Indiana University, School of Public & Environmental Affairs, Bloomington, IN47405 (United States); Chen, CY, E-mail: Celia.Y.Chen@dartmouth.edu [Department of Biological Sciences, Dartmouth College, Hanover, NH03755 (United States)

    2017-01-01

    The goal of this paper is to offer a rigorous analysis of the sigmoid shape single toxin dose-response relationship. The toxin efficacy function is introduced and four special points, including maximum toxin efficacy and inflection points, on the dose-response curve are defined. The special points define three phases of the toxin effect on mortality: (1) toxin concentrations smaller than the first inflection point or (2) larger then the second inflection point imply low mortality rate, and (3) concentrations between the first and the second inflection points imply high mortality rate. Probabilistic interpretation and mathematical analysis for each of the four models, Hill, logit, probit, and Weibull is provided. Two general model extensions are introduced: (1) the multi-target hit model that accounts for the existence of several vital receptors affected by the toxin, and (2) model with a nonzero mortality at zero concentration to account for natural mortality. Special attention is given to statistical estimation in the framework of the generalized linear model with the binomial dependent variable as the mortality count in each experiment, contrary to the widespread nonlinear regression treating the mortality rate as continuous variable. The models are illustrated using standard EPA Daphnia acute (48 h) toxicity tests with mortality as a function of NiCl or CuSO{sub 4} toxin. - Highlights: • The paper offers a rigorous study of a sigmoid dose-response relationship. • The concentration with highest mortality rate is rigorously defined. • A table with four special points for five morality curves is presented. • Two new sigmoid dose-response models have been introduced. • The generalized linear model is advocated for estimation of sigmoid dose-response relationship.

  17. Dosimetric systems of high dose, dose rate and dose uniformity in food and medical products

    International Nuclear Information System (INIS)

    Vargas, J.; Vivanco, M.; Castro, E.

    2014-08-01

    In the Instituto Peruano de Energia Nuclear (IPEN) we use the chemical dosimetry Astm-E-1026 Fricke as a standard dosimetric system of reference and different routine dosimetric systems of high doses, according to the applied doses to obtain the desired effects in the treated products and the doses range determined for each type of dosimeter. Fricke dosimetry is a chemical dosimeter in aqueous solution indicating the absorbed dose by means an increase in absorbance at a specific wavelength. A calibrated spectrophotometer with controlled temperature is used to measure absorbance. The adsorbed dose range should cover from 20 to 400 Gy, the Fricke solution is extremely sensitive to organic impurities, to traces of metal ions, in preparing chemical products of reactive grade must be used and the water purity is very important. Using the referential standard dosimetric system Fricke, was determined to March 5, 2013, using the referential standard dosimetric system Astm-1026 Fricke, were irradiated in triplicate Fricke dosimeters, to 5 irradiation times (20; 30; 40; 50 and 60 seconds) and by linear regression, the dose rate of 5.400648 kGy /h was determined in the central point of the irradiation chamber (irradiator Gamma cell 220 Excel), applying the decay formula, was compared with the obtained results by manufacturers by means the same dosimetric system in the year of its manufacture, being this to the date 5.44691 kGy /h, with an error rate of 0.85. After considering that the dosimetric solution responds to the results, we proceeded to the irradiation of a sample of 200 g of cereal instant food, 2 dosimeters were placed at the lateral ends of the central position to maximum dose and 2 dosimeters in upper and lower ends as minimum dose, they were applied same irradiation times; for statistical analysis, the maximum dose rate was 6.1006 kGy /h and the minimum dose rate of 5.2185 kGy /h; with a dose uniformity of 1.16. In medical material of micro pulverized bone for

  18. Patient-specific radiation dose and cancer risk for pediatric chest CT.

    Science.gov (United States)

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

    2011-06-01

    To estimate patient-specific radiation dose and cancer risk for pediatric chest computed tomography (CT) and to evaluate factors affecting dose and risk, including patient size, patient age, and scanning parameters. The institutional review board approved this study and waived informed consent. This study was HIPAA compliant. The study included 30 patients (0-16 years old), for whom full-body computer models were recently created from clinical CT data. A validated Monte Carlo program was used to estimate organ dose from eight chest protocols, representing clinically relevant combinations of bow tie filter, collimation, pitch, and tube potential. Organ dose was used to calculate effective dose and risk index (an index of total cancer incidence risk). The dose and risk estimates before and after normalization by volume-weighted CT dose index (CTDI(vol)) or dose-length product (DLP) were correlated with patient size and age. The effect of each scanning parameter was studied. Organ dose normalized by tube current-time product or CTDI(vol) decreased exponentially with increasing average chest diameter. Effective dose normalized by tube current-time product or DLP decreased exponentially with increasing chest diameter. Chest diameter was a stronger predictor of dose than weight and total scan length. Risk index normalized by tube current-time product or DLP decreased exponentially with both chest diameter and age. When normalized by DLP, effective dose and risk index were independent of collimation, pitch, and tube potential (chest CT protocols. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101900/-/DC1. RSNA, 2011

  19. High dose tetrabromobisphenol A impairs hippocampal neurogenesis and memory retention.

    Science.gov (United States)

    Kim, Ah Hyun; Chun, Hye Jeong; Lee, Seulah; Kim, Hyung Sik; Lee, Jaewon

    2017-08-01

    Tetrabromobisphenol A (TBBPA) is a brominated flame retardant that is commonly used in commercial and household products, such as, computers, televisions, mobile phones, and electronic boards. TBBPA can accumulate in human body fluids, and it has been reported that TBBPA possesses endocrine disruptive activity. However, the neurotoxic effect of TBBPA on hippocampal neurogenesis has not yet been investigated. Accordingly, the present study was undertaken to evaluate the effect of TBBPA on adult hippocampal neurogenesis and cognitive function. Male C57BL/6 mice were orally administrated vehicle or TBBPA (20 mg/kg, 100 mg/kg, or 500 mg/kg daily) for two weeks. TBBPA was observed to significantly and dose-dependently reduce the survival of newly generated cells in the hippocampus but not to affect the proliferation of newly generated cells. Numbers of hippocampal BrdU and NeuN positive cells were dose-dependently reduced by TBBPA, indicating impaired neurogenesis in the hippocampus. Interestingly, glial activation without neuronal death was observed in hippocampi exposed to TBBPA. Furthermore, memory retention was found to be adversely affected by TBBPA exposure by a mechanism involving suppression of the BDNF-CREB signaling pathway. The study suggests high dose TBBPA disrupts hippocampal neurogenesis and induces associated memory deficits. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Assessment of Effective Dose Equivalent of Indoor 222Rn Daughters in Inchass

    International Nuclear Information System (INIS)

    Ali, E.M.; Taha, T.M.; Gomaa, M.A.; El-Hussein, A.M.; Ahmad, A.A.

    2000-01-01

    The dominant component of natural radiation dose for the general population comes from the radon gas 222 Rn and its short-lived decay products, Ra A ( 214 Po), Ra B ( 214 Pb), Ra C ( 214 Bi), Ra C( 214 Po) in the breathing air. The objective of the present work is to assess the affective dose equivalent of the inhalation exposure of indoor 222 Rn for occupational workers. Average indon concentrations (Bqm -3 ) were monitored in several departments in Nuclear Research Center by radon monitor. We have calculated the lung dose equivalent and the effective dose equivalent for the Egyptian workers due to inhalation exposure of an equilibrium equivalent concentrations of radon daughters which varies from 0.27 to 2.5 mSvy -1 and 0.016 to 0.152mSvy -1 respectively. The annual effective doses obtained are within the accepted range of ICRP recommendations

  1. Evaluation of the dose uniformity for double-plane high dose rate interstitial breast implants with the use of dose reference points and dose non-uniformity ratio

    International Nuclear Information System (INIS)

    MAjor, T.; Polgar, C.; Somogyi, A.; Nemeth, G.

    2000-01-01

    This study investigated the influence of dwell time optimizations on dose uniformity characterized by dose values in dose points and dose non-uniformity ratio (DNR) and analyzed which implant parameters have influence on the DNR. Double-plane breast implants with catheters arranged in triangular pattern were used for the calculations. At a typical breast implant, dose values in dose reference points inside the target volume and volumes enclosed by given isodose surfaces were calculated and compared for non-optimized and optimized implants. The same 6-cm treatment length was used for the comparisons. Using different optimizations plots of dose non-uniformity ratio as a function of catheter separation, source step size, number of catheters, length of active sections were drawn and the minimum DNR values were determined. Optimization resulted in less variation in dose values over dose points through the whole volume and in the central plane only compared to the non-optimized case. At implant configurations consisting of seven catheters with 15-mm separation, 5-mm source step size and various active lengths adapted according to the type of optimization, the no optimization, geometrical (volume mode) and dose point (on dose points and geometry) optimization resulted in similar treatment volumes, but an increased high dose volume was observed due to the optimization. The dose non-uniformity ratio always had the minimum at average dose over dose normalization points, defined in the midpoints between the catheters through the implant volume. The minimum value of DNR depended on catheter separation, source step size, active length and number of catheters. The optimization had only a small influence on DNR. In addition to the reference points in the central plane only, dose points positioned in the whole implant volume can be used for evaluating the dose uniformity of interstitial implants. The dose optimization increases not only the dose uniformity within the implant but

  2. CT patterns of fungal pulmonary infections of the lung: Comparison of standard-dose and simulated low-dose CT

    International Nuclear Information System (INIS)

    Christe, Andreas; Lin, Margaret C.; Yen, Andrew C.; Hallett, Rich L.; Roychoudhury, Kingshuk; Schmitzberger, Florian; Fleischmann, Dominik; Leung, Ann N.; Rubin, Geoffry D.; Vock, Peter; Roos, Justus E.

    2012-01-01

    Purpose: To assess the effect of radiation dose reduction on the appearance and visual quantification of specific CT patterns of fungal infection in immuno-compromised patients. Materials and methods: Raw data of thoracic CT scans (64 × 0.75 mm, 120 kVp, 300 reference mAs) from 41 consecutive patients with clinical suspicion of pulmonary fungal infection were collected. In 32 patients fungal infection could be proven (median age of 55.5 years, range 35–83). A total of 267 cuboids showing CT patterns of fungal infection and 27 cubes having no disease were reconstructed at the original and 6 simulated tube currents of 100, 40, 30, 20, 10, and 5 reference mAs. Eight specific fungal CT patterns were analyzed by three radiologists: 76 ground glass opacities, 42 ground glass nodules, 51 mixed, part solid, part ground glass nodules, 36 solid nodules, 5 lobulated nodules, 6 spiculated nodules, 14 cavitary nodules, and 37 foci of air-space disease. The standard of reference was a consensus subjective interpretation by experts whom were not readers in the study. Results: The mean sensitivity and standard deviation for detecting pathological cuboids/disease using standard dose CT was 0.91 ± 0.07. Decreasing dose did not affect sensitivity significantly until the lowest dose level of 5 mAs (0.87 ± 0.10, p = 0.012). Nodular pattern discrimination was impaired below the dose level of 30 reference mAs: specificity for fungal ‘mixed nodules’ decreased significantly at 20, 10 and 5 reference mAs (p < 0.05). At lower dose levels, classification drifted from ‘solid’ to ‘mixed nodule’, although no lesion was missed. Conclusion: Our simulation data suggest that tube current levels can be reduced from 300 to 30 reference mAs without impairing the diagnostic information of specific CT patterns of pulmonary fungal infections

  3. Dose gradient curve: A new tool for evaluating dose gradient.

    Science.gov (United States)

    Sung, KiHoon; Choi, Young Eun

    2018-01-01

    Stereotactic radiotherapy, which delivers an ablative high radiation dose to a target volume for maximum local tumor control, requires a rapid dose fall-off outside the target volume to prevent extensive damage to nearby normal tissue. Currently, there is no tool to comprehensively evaluate the dose gradient near the target volume. We propose the dose gradient curve (DGC) as a new tool to evaluate the quality of a treatment plan with respect to the dose fall-off characteristics. The average distance between two isodose surfaces was represented by the dose gradient index (DGI) estimated by a simple equation using the volume and surface area of isodose levels. The surface area was calculated by mesh generation and surface triangulation. The DGC was defined as a plot of the DGI of each dose interval as a function of the dose. Two types of DGCs, differential and cumulative, were generated. The performance of the DGC was evaluated using stereotactic radiosurgery plans for virtual targets. Over the range of dose distributions, the dose gradient of each dose interval was well-characterized by the DGC in an easily understandable graph format. Significant changes in the DGC were observed reflecting the differences in planning situations and various prescription doses. The DGC is a rational method for visualizing the dose gradient as the average distance between two isodose surfaces; the shorter the distance, the steeper the dose gradient. By combining the DGC with the dose-volume histogram (DVH) in a single plot, the DGC can be utilized to evaluate not only the dose gradient but also the target coverage in routine clinical practice.

  4. Factors affecting the absorption and excretion of lead in the rat

    International Nuclear Information System (INIS)

    Conrad, M.E.; Barton, J.C.

    1978-01-01

    A reliable method for studying lead absorption and excretion in rats is described. Lead absorption occurs primarily in the duodenum where lead enters the epithelial mucosal cells. There is a relative mucosal block for lead with increasing intraluminal doses. Certain substances which bind lead and increase its solubility enhance its absorption. Iron, zinc, and calcium decrease the absorption of lead without affecting its solubility, probably by competing for shared absorptive receptors in the intestinal mucosa. The total body burden of lead does not affect lead absorption. Thus, lead does not have a feedback mechanism which limits absorption. Lead absorption is increased during rapid periods of growth and in iron-deficient animals. It is diminished with starvation and in iron-overloaded animals. The excretion and kinetics of tracer doses of radiolead were quantified. Erythrocytes seem to serve an important role in transport. Excretion occurs in urine and stool. Bile is an important route of excretion in the gut. Although most of a tracer dose is rapidly excreted, the excretory process is limited permitting lead accumulation primarily in bone

  5. Dose rate influence in the response of the amber 3042 perspex Dosimeter, batch l

    International Nuclear Information System (INIS)

    Prieto Miranda, E. F.; Barrera Gonzalez, G.

    2001-01-01

    The answer of the dosimetry systems is affected by several factors , as the temperature, humidity, light, concentration of oxygen, dose rate, energy spectrum and one can also add the technological conditions of the irradiation process. It should be known as these factors influence in each one of the different dosimetry systems and this way to minimize their effect in the value of the absorbed dose and to obtain exact values . The objective of this paper is to know the influence of the dose rate in the value of the absorbed dose in the Amber 3042 Perspex dosimeters, Batch L, for different measurement wavelengths, as well as, the relation between the post-irradiation time and the induced specific absorbance value in function of the absorbed dose

  6. Dose properties of x-ray beams produced by laser-wakefield-accelerated electrons

    International Nuclear Information System (INIS)

    Kainz, K K; Hogstrom, K R; Antolak, J A; Almond, P R; Bloch, C D

    2005-01-01

    Given that laser wakefield acceleration (LWFA) has been demonstrated experimentally to accelerate electron beams to energies beyond 25 MeV, it is reasonable to assess the ability of existing LWFA technology to compete with conventional radiofrequency linear accelerators in producing electron and x-ray beams for external-beam radiotherapy. We present calculations of the dose distributions (off-axis dose profiles and central-axis depth dose) and dose rates of x-ray beams that can be produced from electron beams that are generated using state-of-the-art LWFA. Subsets of an LWFA electron energy distribution were propagated through the treatment head elements (presuming an existing design for an x-ray production target and flattening filter) implemented within the EGSnrc Monte Carlo code. Three x-ray energy configurations (6 MV, 10 MV and 18 MV) were studied, and the energy width ΔE of the electron-beam subsets varied from 0.5 MeV to 12.5 MeV. As ΔE increased from 0.5 MeV to 4.5 MeV, we found that the off-axis and central-axis dose profiles for x-rays were minimally affected (to within about 3%), a result slightly different from prior calculations of electron beams broadened by scattering foils. For ΔE of the order of 12 MeV, the effect on the off-axis profile was of the order of 10%, but the central-axis depth dose was affected by less than 2% for depths in excess of about 5 cm beyond d max . Although increasing ΔE beyond 6.5 MeV increased the dose rate at d max by more than 10 times, the absolute dose rates were about 3 orders of magnitude below those observed for LWFA-based electron beams at comparable energies. For a practical LWFA-based x-ray device, the beam current must be increased by about 4-5 orders of magnitude. (note)

  7. Low-dose effect of developmental bisphenol A exposure on sperm count and behaviour in rats

    DEFF Research Database (Denmark)

    Hass, Ulla; Christiansen, Sofie; Boberg, Julie

    2016-01-01

    /day. In the offspring, growth, sexual maturation, weights and histopathology of reproductive organs, oestrus cyclicity and sperm counts were assessed. Neurobehavioural development was investigated using a behavioural testing battery including tests for motor activity, sweet preference, anxiety and spatial learning....... Decreased sperm count was found at the lowest bisphenol A dose, that is 25 μg/kg/day, but not at the higher doses. Reproductive organ weight and histology were not affected and no behavioural effects were seen in male offspring. In the female offspring, exposure to 25 μg/kg bw/day bisphenol A dose resulted...... not significantly affected. In conclusion, the present study using a robust experimental study design, has shown that developmental exposure to 25 μg/kg bw/day bisphenol A can cause adverse effects on fertility (decreased sperm count), neurodevelopment (masculinization of spatial learning in females) and lead...

  8. Optimized dose distribution of a high dose rate vaginal cylinder

    International Nuclear Information System (INIS)

    Li Zuofeng; Liu, Chihray; Palta, Jatinder R.

    1998-01-01

    Purpose: To present a comparison of optimized dose distributions for a set of high-dose-rate (HDR) vaginal cylinders calculated by a commercial treatment-planning system with benchmark calculations using Monte-Carlo-calculated dosimetry data. Methods and Materials: Optimized dose distributions using both an isotropic and an anisotropic dose calculation model were obtained for a set of HDR vaginal cylinders. Mathematical optimization techniques available in the computer treatment-planning system were used to calculate dwell times and positions. These dose distributions were compared with benchmark calculations with TG43 formalism and using Monte-Carlo-calculated data. The same dwell times and positions were used for a quantitative comparison of dose calculated with three dose models. Results: The isotropic dose calculation model can result in discrepancies as high as 50%. The anisotropic dose calculation model compared better with benchmark calculations. The differences were more significant at the apex of the vaginal cylinder, which is typically used as the prescription point. Conclusion: Dose calculation models available in a computer treatment-planning system must be evaluated carefully to ensure their correct application. It should also be noted that when optimized dose distribution at a distance from the cylinder surface is calculated using an accurate dose calculation model, the vaginal mucosa dose becomes significantly higher, and therefore should be carefully monitored

  9. A wide range survey meter for estimating γ- and β-dose rates

    International Nuclear Information System (INIS)

    Jones, A.R.

    1980-09-01

    A survey meter has been developed to measure β-dose rates in the range 0.1 - 100 rad/h (1 mGy/h - 1 Gy/h) and γ-dose rates in the range 1 mrad/h - 100 rad/h (10 μGy/h-1 Gy/h). It also provides an audible warning of high γ-dose rates and an audible and visible warning when a predetermined γ-dose is exceeded. The report describes the design of the survey meter and presents data measured on the performance of an engineering prototype. Factors which affect performance and have been investigated are temperature, battery voltage (and type of battery), GM counter counting loss, direction of incident radiation, and energy of γ-rays. Finally, the application and calibration of the survey meter are discussed. (auth)

  10. Effect of substerilization doses of radiation on the biology of diamondback moth

    International Nuclear Information System (INIS)

    Omar, D.; Mansor, M.

    1993-01-01

    The pupae of the diamondback moth, Plutella xylostella, were exposed to four substerilizing doses (100, 150, 200 and 250 Gy) of gamma radiation. The fecundity, sterility and progeny development of parental crosses and certain F 1 backcrosses (progeny of irradiated males) were studied in the laboratory. All doses caused sterility in the parental crosses and F 1 backcrosses. Doses above 20 Gy greatly affected the development of larvae in parental crosses of irradiated females with normal males and of irradiated males with irradiated females, as no pupation was observed. The study indicated that a dose between 150 and 200 Gy would be suitable for inherited sterility of the diamondback moth. However, the backcross of progeny from irradiated males showed no significant increase in inheritance of deleterious effects. (author). 10 refs, 7 tabs

  11. Acute topiramate differentially affects human aggressive responding at low vs. moderate doses in subjects with histories of substance abuse and antisocial behavior.

    Science.gov (United States)

    Lane, Scott D; Gowin, Joshua L; Green, Charles E; Steinberg, Joel L; Moeller, F Gerard; Cherek, Don R

    2009-04-01

    Anticonvulsant drugs have demonstrated efficacy in the management of irritability and aggression in a variety of psychiatric populations. We examined the acute effects of topiramate on aggression using a laboratory model of human aggression (PSAP) in individuals at high risk for aggressive and violent behavior.Twelve subjects, on parole/probation and with an Axis-II personality disorder and/or a substance use disorder, received 100, 200, 300, and 400 mg in an ascending sequence, with intervening placebo doses.Subjects participated 2-3 days per week over 4-6 weeks. Due to cognitive side effects at 300 mg, two subjects only completed through the 200 mg dose. Topiramate produced an inverted U-shaped dose response curve, with increases in aggression peaking at 200 mg and a modest decrease at 400 mg. Statistical analysis revealed a polynomial trend for dose (p=0.001). The observed inverted U-shaped function in aggressive responding is consistent with non-human aggression studies of GABA-A modulators. Acute topiramate doses >400 mg may have anti-aggressive effects, but dose levels in the 200-300 mg range may produce increases in aggression and side effects.

  12. Dynamically accumulated dose and 4D accumulated dose for moving tumors

    International Nuclear Information System (INIS)

    Li Heng; Li Yupeng; Zhang Xiaodong; Li Xiaoqiang; Liu Wei; Gillin, Michael T.; Zhu, X. Ronald

    2012-01-01

    Purpose: The purpose of this work was to investigate the relationship between dynamically accumulated dose (dynamic dose) and 4D accumulated dose (4D dose) for irradiation of moving tumors, and to quantify the dose uncertainty induced by tumor motion. Methods: The authors established that regardless of treatment modality and delivery properties, the dynamic dose will converge to the 4D dose, instead of the 3D static dose, after multiple deliveries. The bounds of dynamic dose, or the maximum estimation error using 4D or static dose, were established for the 4D and static doses, respectively. Numerical simulations were performed (1) to prove the principle that for each phase, after multiple deliveries, the average number of deliveries for any given time converges to the total number of fractions (K) over the number of phases (N); (2) to investigate the dose difference between the 4D and dynamic doses as a function of the number of deliveries for deliveries of a “pulsed beam”; and (3) to investigate the dose difference between 4D dose and dynamic doses as a function of delivery time for deliveries of a “continuous beam.” A Poisson model was developed to estimate the mean dose error as a function of number of deliveries or delivered time for both pulsed beam and continuous beam. Results: The numerical simulations confirmed that the number of deliveries for each phase converges to K/N, assuming a random starting phase. Simulations for the pulsed beam and continuous beam also suggested that the dose error is a strong function of the number of deliveries and/or total deliver time and could be a function of the breathing cycle, depending on the mode of delivery. The Poisson model agrees well with the simulation. Conclusions: Dynamically accumulated dose will converge to the 4D accumulated dose after multiple deliveries, regardless of treatment modality. Bounds of the dynamic dose could be determined using quantities derived from 4D doses, and the mean dose

  13. Smartphone apps for calculating insulin dose: a systematic assessment.

    Science.gov (United States)

    Huckvale, Kit; Adomaviciute, Samanta; Prieto, José Tomás; Leow, Melvin Khee-Shing; Car, Josip

    2015-05-06

    Medical apps are widely available, increasingly used by patients and clinicians, and are being actively promoted for use in routine care. However, there is little systematic evidence exploring possible risks associated with apps intended for patient use. Because self-medication errors are a recognized source of avoidable harm, apps that affect medication use, such as dose calculators, deserve particular scrutiny. We explored the accuracy and clinical suitability of apps for calculating medication doses, focusing on insulin calculators for patients with diabetes as a representative use for a prevalent long-term condition. We performed a systematic assessment of all English-language rapid/short-acting insulin dose calculators available for iOS and Android. Searches identified 46 calculators that performed simple mathematical operations using planned carbohydrate intake and measured blood glucose. While 59% (n = 27/46) of apps included a clinical disclaimer, only 30% (n = 14/46) documented the calculation formula. 91% (n = 42/46) lacked numeric input validation, 59% (n = 27/46) allowed calculation when one or more values were missing, 48% (n = 22/46) used ambiguous terminology, 9% (n = 4/46) did not use adequate numeric precision and 4% (n = 2/46) did not store parameters faithfully. 67% (n = 31/46) of apps carried a risk of inappropriate output dose recommendation that either violated basic clinical assumptions (48%, n = 22/46) or did not match a stated formula (14%, n = 3/21) or correctly update in response to changing user inputs (37%, n = 17/46). Only one app, for iOS, was issue-free according to our criteria. No significant differences were observed in issue prevalence by payment model or platform. The majority of insulin dose calculator apps provide no protection against, and may actively contribute to, incorrect or inappropriate dose recommendations that put current users at risk of both catastrophic overdose and more

  14. A review of radiology staff doses and dose monitoring requirements

    International Nuclear Information System (INIS)

    Martin, C. J.

    2009-01-01

    Studies of radiation doses received during X-ray procedures by radiology, cardiology and other clinical staff have been reviewed. Data for effective dose (E), and doses to the eyes, thyroid, hands and legs have been analysed. These data have been supplemented with local measurements to determine the most exposed part of the hand for monitoring purposes. There are ranges of 60-100 in doses to individual tissues reported in the literature for similar procedures at different centres. While ranges in the doses per unit dose-area product (DAP) are between 10 and 25, large variations in dose result from differences in the sensitivity of the X-ray equipment, the type of procedure and the operator technique, but protection factors are important in maintaining dose levels as low as possible. The influence of shielding devices is significant for determining the dose to the eyes and thyroid, and the position of the operator, which depends on the procedure, is the most significant factor determining doses to the hands. A second body dosemeter worn at the level of the collar is recommended for operators with high workloads for use in assessment of effective dose and the dose to the eye. It is proposed that the third quartile values from the distributions of dose per unit DAP identified in the review might be employed in predicting the orders of magnitude of doses to the eye, thyroid and hands, based on interventional operator workloads. Such dose estimates could be employed in risk assessments when reviewing protection and monitoring requirements. A dosemeter worn on the little finger of the hand nearest to the X-ray tube is recommended for monitoring the hand. (authors)

  15. Effect of dose increase or cimetidine co-administration on albendazole bioavailability

    NARCIS (Netherlands)

    Schipper, H. G.; Koopmans, R. P.; Nagy, J.; Butter, J. J.; Kager, P. A.; van Boxtel, C. J.

    2000-01-01

    The low bioavailability of albendazole affects the therapeutic response in patients with echinococcosis. Cimetidine co-administration is reported to improve bioavailability. To analyze the assumed dose-dependent bioavailability of albendazole, we administered 5 to 30 mg/kg albendazole to 6 male

  16. Radiation Dose and Image Quality from Coronary Angiography in 320-Detecor Row CT

    International Nuclear Information System (INIS)

    Thanomphudsa, J.; Krisanachinda, A.; Tumkosit, M.

    2012-01-01

    Introduction: Coronary Computed Tomography Angiography examinations are increasing rapidly. New Computed Tomography has been developed to improve image quality with the patient dose reduction. The purpose of this study is to evaluate radiation dose and image quality of Coronary Computed Tomography Angiography in patients using 320-detector row CT. Methods: Forty-one patients referred for cardiac CT examinations at King Chulalongkorn Memorial Hospital were included in this study. All coronary computed tomographic angiography (CCTA) examinations were performed on the 320-detector row CT, Toshiba Aquilion One. Scanning protocol was investigated on dose estimates and image quality. Patients were scanned base on heart rate (HR) by HR 75 bpm use retrospective with dose modulation. Scanning parameters, kVp, mAs, HR, BMI, CTDIvol(mGy) and DLP(mGy.cm), were recorded to study the factors affecting the image quality and patient dose. And mA and kVp setting depend on BMI of the patient. Effective dose is calculated from DLP using specific conversion factor. The image quality was evaluated in 4 vessels by two radiologists. Noise assessment was also studied quantitatively. Results: The patient effective dose in prospective gating 70-80% was 3.6 ± 0.9 mSv, prospective gating 30-80% (1R-R) was 6.3 ± 1.9 mSv, and 30-80% (2R-R) was 10.8 ± 1.8 mSv and in retrospective with tube current modulation was 12.1± 7.7 mSv. Image noise was highest in PGT 70-80% 1R-R and decreased in RGT with tube current modulation, PGT 30-80% 1R-R and lowest in PGT 30-80% 2 R-R. And overall qualitative image quality was mostly good to excellent score. Discussion: The heart rate, heart rate variability and disease of the patient are affecting in the radiation dose and image quality so the suitable acquisition protocol used could be necessary. the effective dose and the image noise for the image quality. (author)

  17. Effects of fibroblast growth factor-2 on the expression and regulation of chemokines in human dental pulp cells.

    Science.gov (United States)

    Kim, Young-Suk; Min, Kyung-San; Jeong, Dong-Ho; Jang, Jun-Hyeog; Kim, Hae-Won; Kim, Eun-Cheol

    2010-11-01

    Fibroblast growth factor-2 (FGF-2) participates in both hematopoiesis and osteogenesis; however, the effects of FGF-2 on chemokines during odontoblastic differentiation have not been reported. This study investigated whether human dental pulp cells (HDPCs) treated with FGF-2 could express chemokines during differentiation into odontoblastic cells and sought to identify its underlying mechanism of action. To analyze differentiation, we measured alkaline phosphatase (ALP) activity, calcified nodule formation by alizarin red staining, and marker RNA (mRNA) expression by reverse-transcriptase polymerase chain reaction (RT-PCR). Expression of chemokines, such as interleukin-6 (IL-6), IL-8, monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1α (MIP-1α), and MIP-3α, were evaluated by RT-PCR. ALP activity, the mineralization, and mRNA expression for odontoblastic markers were enhanced by FGF-2 in HDPCs. FGF-2 also up-regulated the expression of IL-6, IL-8, MCP-1, MIP-1α, and MIP-3α mRNAs, which were attenuated by inhibitors of p38, ERK1/2 and p38 MAP kinases, protein kinase C, phosphoinositide-3 kinase, and NF-κB. Taken together, these data suggest that FGF-2 plays a role not only as a differentiation inducing factor in the injury repair processes of pulpal tissue but also as a positive regulator of chemokine expression, which may help in tissue engineering and pulp regeneration using HDPCs. However, the fate of odontoblastic or osteoblastic differentiation, effective local delivery for FGF-2, interaction of chemotatic and odontogenic factors, and other limitations will need to be overcome before a major modality for the treatment of pulp disease. Copyright © 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  18. In Vitro Study of Dentin Hypersensitivity Treated by 980-nm Diode Laser.

    Science.gov (United States)

    Liu, Ying; Gao, Jie; Gao, Yan; Xu, Shuaimei; Zhan, Xueling; Wu, Buling

    2013-01-01

    To investigate the ultrastructural changes of dentin irradiated with 980-nm diode laser under different parameters and to observe the morphological alterations of odontoblasts and pulp tissue to determine the safety parameters of 980-nm diode laser in the treatment of dentin hypersensitivity (DH). Twenty extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into four areas and was irradiated by 980-nm diode laser under different parameters: Group A: control group, 0 J/cm(2); Group B: 2 W/CW (continuous mode), 166 J/cm(2); Group C: 3W/CW, 250 J/cm(2); and Group D: 4W/CW, 333 J/cm(2). Ten additional extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into two areas and was irradiated by 980-nm diode laser: Group E: control group, 0 J/cm(2); and Group F: 2.0 W/CW, 166 J/cm(2). The morphological alterations of the dentin surfaces and odontoblasts were examined with scanning electron microscopy (SEM), and the morphological alterations of the dental pulp tissue irradiated by laser were observed with an upright microscope. The study demonstrated that dentinal tubules can be entirely blocked after irradiation by 980-nm diode laser, regardless of the parameter setting. Diode laser with settings of 2.0 W and 980-nm sealed exposed dentin tubules effectively, and no significant morphological alterations of the pulp and odontoblasts were observed after irradiation. Irradiation with 980-nm diode laser could be effective for routine clinical treatment of DH, and 2.0W/CW (166 J/cm(2)) was a suitable energy parameter due to its rapid sealing of the exposed dentin tubules and its safety to the odontoblasts and pulp tissue.

  19. In Vitro Study of Dentin Hypersensitivity Treated by 980-nm Diode Laser

    Science.gov (United States)

    Liu, Ying; Gao, Jie; Gao, Yan; XU, Shuaimei; Zhan, Xueling; Wu, Buling

    2013-01-01

    Introduction: To investigate the ultrastructural changes of dentin irradiated with 980-nm diode laser under different parameters and to observe the morphological alterations of odontoblasts and pulp tissue to determine the safety parameters of 980-nm diode laser in the treatment of dentin hypersensitivity (DH). Methods: Twenty extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into four areas and was irradiated by 980-nm diode laser under different parameters: Group A: control group, 0 J/cm2; Group B: 2 W/CW (continuous mode), 166 J/cm2; Group C: 3W/CW, 250 J/cm2; and Group D: 4W/CW, 333 J/cm2. Ten additional extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into two areas and was irradiated by 980-nm diode laser: Group E: control group, 0 J/cm2; and Group F: 2.0 W/CW, 166 J/cm2. The morphological alterations of the dentin surfaces and odontoblasts were examined with scanning electron microscopy (SEM), and the morphological alterations of the dental pulp tissue irradiated by laser were observed with an upright microscope. Results: The study demonstrated that dentinal tubules can be entirely blocked after irradiation by 980-nm diode laser, regardless of the parameter setting. Diode laser with settings of 2.0 W and 980-nm sealed exposed dentin tubules effectively, and no significant morphological alterations of the pulp and odontoblasts were observed after irradiation. Conclusions: Irradiation with 980-nm diode laser could be effective for routine clinical treatment of DH, and 2.0W/CW (166 J/cm2) was a suitable energy parameter due to its rapid sealing of the exposed dentin tubules and its safety to the odontoblasts and pulp tissue. PMID:25606318

  20. A single whole-body low dose X-irradiation does not affect L1, B1 and IAP repeat element DNA methylation longitudinally.

    Directory of Open Access Journals (Sweden)

    Michelle R Newman

    Full Text Available The low dose radioadaptive response has been shown to be protective against high doses of radiation as well as aging-induced genomic instability. We hypothesised that a single whole-body exposure of low dose radiation would induce a radioadaptive response thereby reducing or abrogating aging-related changes in repeat element DNA methylation in mice. Following sham or 10 mGy X-irradiation, serial peripheral blood sampling was performed and differences in Long Interspersed Nucleic Element 1 (L1, B1 and Intracisternal-A-Particle (IAP repeat element methylation between samples were assessed using high resolution melt analysis of PCR amplicons. By 420 days post-irradiation, neither radiation- or aging-related changes in the methylation of peripheral blood, spleen or liver L1, B1 and IAP elements were observed. Analysis of the spleen and liver tissues of cohorts of untreated aging mice showed that the 17-19 month age group exhibited higher repeat element methylation than younger or older mice, with no overall decline in methylation detected with age. This is the first temporal analysis of the effect of low dose radiation on repeat element methylation in mouse peripheral blood and the first to examine the long term effect of this dose on repeat element methylation in a radiosensitive tissue (spleen and a tissue fundamental to the aging process (liver. Our data indicate that the methylation of murine DNA repeat elements can fluctuate with age, but unlike human studies, do not demonstrate an overall aging-related decline. Furthermore, our results indicate that a low dose of ionising radiation does not induce detectable changes to murine repeat element DNA methylation in the tissues and at the time-points examined in this study. This radiation dose is relevant to human diagnostic radiation exposures and suggests that a dose of 10 mGy X-rays, unlike high dose radiation, does not cause significant short or long term changes to repeat element or global DNA

  1. ''Low dose'' and/or ''high dose'' in radiation protection: A need to setting criteria for dose classification

    International Nuclear Information System (INIS)

    Sohrabi, M.

    1997-01-01

    The ''low dose'' and/or ''high dose'' of ionizing radiation are common terms widely used in radiation applications, radiation protection and radiobiology, and natural radiation environment. Reading the title, the papers of this interesting and highly important conference and the related literature, one can simply raise the question; ''What are the levels and/or criteria for defining a low dose or a high dose of ionizing radiation?''. This is due to the fact that the criteria for these terms and for dose levels between these two extreme quantities have not yet been set, so that the terms relatively lower doses or higher doses are usually applied. Therefore, setting criteria for classification of radiation doses in the above mentioned areas seems a vital need. The author while realizing the existing problems to achieve this important task, has made efforts in this paper to justify this need and has proposed some criteria, in particular for the classification of natural radiation areas, based on a system of dose limitation. (author)

  2. Correspondence model-based 4D VMAT dose simulation for analysis of local metastasis recurrence after extracranial SBRT

    Science.gov (United States)

    Sothmann, T.; Gauer, T.; Wilms, M.; Werner, R.

    2017-12-01

    The purpose of this study is to introduce a novel approach to incorporate patient-specific breathing variability information into 4D dose simulation of volumetric arc therapy (VMAT)-based stereotactic body radiotherapy (SBRT) of extracranial metastases. Feasibility of the approach is illustrated by application to treatment planning and motion data of lung and liver metastasis patients. The novel 4D dose simulation approach makes use of a regression-based correspondence model that allows representing patient motion variability by breathing signal-steered interpolation and extrapolation of deformable image registration motion fields. To predict the internal patient motion during treatment with only external breathing signal measurements being available, the patients’ internal motion information and external breathing signals acquired during 4D CT imaging were correlated. Combining the correspondence model, patient-specific breathing signal measurements during treatment and time-resolved information about dose delivery, reconstruction of a motion variability-affected dose becomes possible. As a proof of concept, the proposed approach is illustrated by a retrospective 4D simulation of VMAT-based SBRT treatment of ten patients with 15 treated lung and liver metastases and known clinical endpoints for the individual metastases (local metastasis recurrence yes/no). Resulting 4D-simulated dose distributions were compared to motion-affected dose distributions estimated by standard 4D CT-only dose accumulation and the originally (i.e. statically) planned dose distributions by means of GTV D98 indices (dose to 98% of the GTV volume). A potential linkage of metastasis-specific endpoints to differences between GTV D98 indices of planned and 4D-simulated dose distributions was analyzed.

  3. The optimal dose of radiation in Hodgkin's disease: an analysis of clinical and treatment factors affecting in-field disease control

    International Nuclear Information System (INIS)

    Price Mendenhall, Nancy; Lewis Rodrigue, Lori; Moore-Higgs, Giselle J.; Marcus, Robert B.; Million, Rodney R.

    1999-01-01

    Purpose: The purpose of this study is to analyze the effect of radiation dose, as well as other clinical and therapeutic factors, on in-field disease control. Patients and Materials: The study population comprised 232 patients with Stage I and II Hodgkin's disease (HD) treated with curative intent at the University of Florida with radiotherapy (RT) alone (169 patients) or chemotherapy and radiotherapy (CMT) (63 patients). Sites of involvement and radiation doses were prospectively recorded and correlated with sites of disease recurrence. Results: Freedom from relapse and absolute survival rates at 10 years were as follows: 76% and 77%, entire group; 76% and 80%, RT group; 79% and 70%, CMT group; 85% and 78%, Stage I; and 71% and 77%, Stage II. Treatment failure occurred in 50 patients (22%) including in-field failure in 22 patients (9%). In-field failure was rare in electively treated sites. Multivariate analysis of clinical factors (tumor size, number of sites involved, B-symptoms, gender, histology, age, and site of involvement) and treatment factors (use of chemotherapy, number of cycles of chemotherapy, radiation dose, radiation treatment volume, and radiation treatment time) showed only tumor size (p = 0.0001) to be significantly correlated with in-field disease control. In RT patients, the in-field failure rate according to tumor size was as follows: 0% for ≤ 3 cm; 4% for > 3 cm and ≤ 6 cm; 23% for > 6 cm and ≤ 9 cm; and 36% for > 9 cm. In CMT patients, the in-field failure rate was as follows: 0% for ≤ 3 cm; 0% for > 3 and ≤ 6 cm; 5% for > 6 cm and ≤ 9 cm; and 26% for > 9 cm. In-field recurrence was not a predominant pattern of failure in RT patients with small tumors (≤ 6 cm); thus, the difference in in-field control in tumors ≤ 6 cm between doses ≤ 35 Gy (6%) and doses ≥ 36 Gy (0%) was not statistically significant. In larger tumors (> 6 cm), in-field recurrence was a predominant pattern of failure; the in-field failure rate in RT

  4. [MAXIMUM SINGLE DOSE OF COLLOIDAL SILVER NEGATIVELY AFFECTS ERYTHROPOIESIS IN VITRO].

    Science.gov (United States)

    Tishevskayal, N V; Zakharovl, Y M; Bolotovl, A A; Arkhipenko, Yu V; Sazontova, T G

    2015-01-01

    Erythroblastic islets (EI) of rat bone marrow were cultured for 24 h in the presence of silver nanoparticles (1.07 · 10(-4) mg/ml; 1.07 · 10(-3) mg/ml; and 1.07 · 10(-2) mg/mL). The colloidal silver at 1.07 · 10(-3) mg/ml concentration inhibited the formation of new Elby disrupting contacts of bone marrow macrophages with CFU-E (erythropoiesis de novo) by 65.3% (p Colloidal silver nanoparticles suppressed the reconstruction of erythropoiesis and inhibited the formation of new EI by disrupting contacts of CFU-E and central macrophages with matured erythroidal "crown" (erythropoiesis de repeto). The colloidal silver concentration of 1.07 · 10(-3) mg/ml in the culture medium also reduced the number of self-reconstructing EI by 67.5% (p colloidal silver reduced this value by 93.7% (p Silver nanoparticles retarded maturation of erythroid cells at the stage of oxiphylic normoblast denucleation: 1.07 · 10(-3) mg/ml colloidal silver increased the number of mature El by 53% (p colloidal silver in concentration equivalent to the maximum single dose is related to the effect of silver nanoparticles rather than glycerol present in the colloidal suspension.

  5. Patient doses and radiation risks in film-screen mammography in Finland

    International Nuclear Information System (INIS)

    Servomaa, A.; Parviainen, T.; Komppa, T.

    1995-01-01

    Screen-film mamography is the most sensitive method for the early detection of breast cancer. Breast doses in mamography should be measured for several reasons, especially for the evaluation of patient risk in a screening programme, but also for the assessment and comparison of imaging techniques and equipment performance. In this study, the factors affecting patient doses were assessed by making performance and patient dose measurements; about 50 mammographic units used for screening were included in the study. The lifetime risk as a function of age at exposure was calculated using the average glandular dose, the relative risk model shown in the BEIR V report, and the breast cancer mortality in Finland. The mean surface dose of a 4.5 cm thick phantom was 6.3 mGy, and the mean glandular dose 1.0 mGy. Analysis of the surface dose with respect to film optical density, relative speed of film processing, sensitivity of image receptors, and antiscatter grid showed that the mean surface dose could be decreased by more than 50%. For the screened age group of 50 to 59 years, the risk of exposure-induced death (REID) of breast cancer is about 1.4 x 10 -6 mSv -1 , and the average loss of life expectancy due to the radiation-induced breast cancer deaths (LLE/REID) is about 9.5 years. (Author)

  6. Calculation of dose conversion factors for doses in the fingernails to organ doses at external gamma irradiation in air

    International Nuclear Information System (INIS)

    Khailov, A.M.; Ivannikov, A.I.; Skvortsov, V.G.; Stepanenko, V.F.; Orlenko, S.P.; Flood, A.B.; Williams, B.B.; Swartz, H.M.

    2015-01-01

    Absorbed doses to fingernails and organs were calculated for a set of homogenous external gamma-ray irradiation geometries in air. The doses were obtained by stochastic modeling of the ionizing particle transport (Monte Carlo method) for a mathematical human phantom with arms and hands placed loosely along the sides of the body. The resulting dose conversion factors for absorbed doses in fingernails can be used to assess the dose distribution and magnitude in practical dose reconstruction problems. For purposes of estimating dose in a large population exposed to radiation in order to triage people for treatment of acute radiation syndrome, the calculated data for a range of energies having a width of from 0.05 to 3.5 MeV were used to convert absorbed doses in fingernails to corresponding doses in organs and the whole body as well as the effective dose. Doses were assessed based on assumed rates of radioactive fallout at different time periods following a nuclear explosion. - Highlights: • Elemental composition and density of nails were determined. • MIRD-type mathematical human phantom with arms and hands was created. • Organ doses and doses to nails were calculated for external photon exposure in air. • Effective dose and nail doses values are close for rotational and soil surface exposures.

  7. Dose distribution in organs: patient-specific phantoms versus reference phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, I.V.B., E-mail: isabelle.lacerda@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife (Brazil); Vieira, J.W. [Instituto Federal de Pernambuco (IFPE), Recife (Brazil); Oliveira, M.L.; Lima, F.R.A. [Centro Regional de Ciências Nucleares do Nordeste (CRCN-NE/CNEN-PB), Recife (Brazil)

    2017-07-01

    Discrepancies between ICRP phantoms and real patients lead to disparities on patient-dose estimations. This paper aims to compare distribution of dose in organs of male/female specific-phantoms and ICRP reference phantoms. The absorbed dose estimation was performed using the EGSnrc Monte Carlo code and a parallel source algorithm. In this work were used a patient-specific phantom for a man (1.73m/70.3kg) and another for a woman (1.63m/60.3kg) and the male and female ICRP reference phantoms. The comparison of the absorbed dose from each phantom gender was performed using the relative error. The results were expressed in terms of conversion coefficients to brain, lungs, liver and kidneys. The greatest absolute relative error between the organs of the patient-specific phantom and the reference phantom was 22.92% in the liver and 62.84% in the kidneys, respectively for man and woman. There are errors that cannot be disregarded. This paper shows the need for a specific study for each patient or for the population of each country, since there are different body types, which affects the distribution of the organ doses. (author)

  8. Dose distribution in organs: patient-specific phantoms versus reference phantoms

    International Nuclear Information System (INIS)

    Lacerda, I.V.B.; Vieira, J.W.; Oliveira, M.L.; Lima, F.R.A.

    2017-01-01

    Discrepancies between ICRP phantoms and real patients lead to disparities on patient-dose estimations. This paper aims to compare distribution of dose in organs of male/female specific-phantoms and ICRP reference phantoms. The absorbed dose estimation was performed using the EGSnrc Monte Carlo code and a parallel source algorithm. In this work were used a patient-specific phantom for a man (1.73m/70.3kg) and another for a woman (1.63m/60.3kg) and the male and female ICRP reference phantoms. The comparison of the absorbed dose from each phantom gender was performed using the relative error. The results were expressed in terms of conversion coefficients to brain, lungs, liver and kidneys. The greatest absolute relative error between the organs of the patient-specific phantom and the reference phantom was 22.92% in the liver and 62.84% in the kidneys, respectively for man and woman. There are errors that cannot be disregarded. This paper shows the need for a specific study for each patient or for the population of each country, since there are different body types, which affects the distribution of the organ doses. (author)

  9. DOZIM - evaluation dose code for nuclear accident

    International Nuclear Information System (INIS)

    Oprea, I.; Musat, D.; Ionita, I.

    2008-01-01

    During a nuclear accident an environmentally significant fission products release can happen. In that case it is not possible to determine precisely the air fission products concentration and, consequently, the estimated doses will be affected by certain errors. The stringent requirement to cope with a nuclear accident, even minor, imposes creation of a computation method for emergency dosimetric evaluations needed to compare the measurement data to certain reference levels, previously established. These comparisons will allow a qualified option regarding the necessary actions to diminish the accident effects. DOZIM code estimates the soil contamination and the irradiation doses produced either by radioactive plume or by soil contamination. Irradiations either on whole body or on certain organs, as well as internal contamination doses produced by isotope inhalation during radioactive plume crossing are taken into account. The calculus does not consider neither the internal contamination produced by contaminated food consumption, or that produced by radioactive deposits resuspension. The code is recommended for dose computation on the wind direction, at distances from 10 2 to 2 x 10 4 m. The DOZIM code was utilized for three different cases: - In air TRIGA-SSR fuel bundle destruction with different input data for fission products fractions released into the environment; - Chernobyl-like accident doses estimation; - Intervention areas determination for a hypothetical severe accident at Cernavoda Nuclear Power Plant. For the first case input data and results (for a 60 m emission height without iodine retention on active coal filters) are presented. To summarize, the DOZIM code conception allows the dose estimation for any nuclear accident. Fission products inventory, released fractions, emission conditions, atmospherical and geographical parameters are the input data. Dosimetric factors are included in the program. The program is in FORTRAN IV language and was run on

  10. Higher hydrocortisone dose increases bilirubin in hypopituitary patients- results from an RCT.

    Science.gov (United States)

    Werumeus Buning, Jorien; Kootstra-Ros, Jenny E; Brummelman, Pauline; van den Berg, Gerrit; van der Klauw, Melanie; Wolffenbuttel, Bruce H R; van Beek, André P; Dullaart, Robin P F

    2016-05-01

    Bilirubin has anti-oxidative and anti-inflammatory properties, which may explain its proposed protective effects on the development of cardiometabolic disorders. Glucocorticoids affect heme oxygenase regulation in vitro, which plays a key role in bilirubin production. Effects of variations in glucocorticoid exposure on circulating bilirubin levels in humans are unknown. Here we tested whether a higher hydrocortisone replacement dose affects circulating bilirubin in hypopituitary patients. A randomized double-blind cross-over study (ClinicalTrials.gov, number NCT01546992) was performed in 47 patients with secondary adrenal failure [10-week exposure to a higher hydrocortisone dose (0·4-0·6 mg/kg body weight) vs. 10 weeks of a lower hydrocortisone dose (0·2-0·3 mg/kg body weight)]. Plasma total bilirubin was increased by 10% from 7 to 8 μM in response to the higher hydrocortisone dose (P = 0·033). This effect was inversely related to age (P = 0·042), but was unaffected by sex, obesity and (replacement for) other hormonal insufficiencies. The higher hydrocortisone dose also resulted in lower alkaline phosphatase (P = 0·006) and aspartate aminotransferase activities (P = 0·001). Bilirubin is modestly increased in response to higher glucocorticoid exposure in humans, in conjunction with lower alkaline phosphatase and aspartate aminotransferase activities, which are supposed to represent biomarkers of a pro-inflammatory state and enhanced liver fat accumulation. © 2016 The Authors. European Journal of Clinical Investigation published by John Wiley & Sons Ltd on behalf of Stichting European Society for Clinical Investigation Journal Foundation.

  11. Background levels and radiation dose yield of o-tyrosine in chicken meat

    International Nuclear Information System (INIS)

    Chuaqui-Offermanns, N.; McDougall, T.

    1991-01-01

    The measurement of o-tyrosine levels in poultry meat is a potential method for postirradiation dosimetry of poultry. The validity of using o-tyrosine for this purpose has not yet been established. As part of the validation process, the o-tyrosine content in unirradiated chicken meat, the radiation dose response curve, and the effects of postirradiation storage on o-tyrosine levels are examined. In 18 individual samples, the mean background level of o-tyrosine was 0.18 +/- 0.11 ppm (wet weight, 70% moisture), and the most frequent background level (60% of the cases) was between 0.05 and 0.15 ppm (wet weight, 70% moisture). In pooled samples of 10 chickens, the mean background level was 0.12 +/- 0.03 ppm (wet weight, 70% moisture). The levels were not significantly affected by storage at 5 degrees C (7 d) or by freezing the sample. The radiation dose response curve was linear within the dose range studied (0 to 10 kGy), with a slope of 0.127 + 0.003 ppm (wet weight)/kGy. Although there was some variation in the intercept (0.132 + 0.013), the slope was the same in all samples tested. Postirradiation storage at either 4 or 8 degrees C until spoilage did not affect the levels of o-tyrosine. These data indicate that o-tyrosine level may be useful for determining the absorbed dose in chicken meat gamma-irradiated to doses greater than 0.6 kGy. Further validation studies are continuing

  12. Variations in 6MV x-ray radiotherapy build-up dose with treatment distance

    International Nuclear Information System (INIS)

    Butson, M.J.; Illawarra Cancer Care Centre, Wollongong, NSW; Cheung, T.; Yu, P.K.N.

    2003-01-01

    Dose in the build up region for high energy x-rays produced by a medical linear accelerator is affected by the x-ray source to patient surface distance (SSD). The use of isocentric treatments whereby the tumour is positions 100cm from the source means that depending of the depth of the tumour and the size of the patient, the SSD can vary from distances of 80cm to 100cm. To achieve larger field sizes, the SSD can also be extended out to 120cm at times. Results have shown that open fields are not significantly affected by SSD changes with deviations in percentage dose being less than 4% of maximum dose for SSD's from 80cm to 120cm SSD. With the introduction of beam modifying devices such as Perspex blocking trays, the effects are significant with a deviation of up to 22% measured at 6MV energy with a 6mm Perspex tray for SSD's from 80cm to 120cm. These variations are largest at the skin surface and reduce with depth. The use of a multi leaf collimator for blocking removes extra skin dose caused by the Perspex block trays with decreasing SSD. Copyright (2003) Australasian College of Physical Scientists and Engineers in Medicine

  13. Dose reduction in pediatric abdominal CT: use of iterative reconstruction techniques across different CT platforms

    International Nuclear Information System (INIS)

    Khawaja, Ranish Deedar Ali; Singh, Sarabjeet; Otrakji, Alexi; Padole, Atul; Lim, Ruth; Nimkin, Katherine; Westra, Sjirk; Kalra, Mannudeep K.; Gee, Michael S.

    2015-01-01

    Dose reduction in children undergoing CT scanning is an important priority for the radiology community and public at large. Drawbacks of radiation reduction are increased image noise and artifacts, which can affect image interpretation. Iterative reconstruction techniques have been developed to reduce noise and artifacts from reduced-dose CT examinations, although reconstruction algorithm, magnitude of dose reduction and effects on image quality vary. We review the reconstruction principles, radiation dose potential and effects on image quality of several iterative reconstruction techniques commonly used in clinical settings, including 3-D adaptive iterative dose reduction (AIDR-3D), adaptive statistical iterative reconstruction (ASIR), iDose, sinogram-affirmed iterative reconstruction (SAFIRE) and model-based iterative reconstruction (MBIR). We also discuss clinical applications of iterative reconstruction techniques in pediatric abdominal CT. (orig.)

  14. Dose reduction in pediatric abdominal CT: use of iterative reconstruction techniques across different CT platforms

    Energy Technology Data Exchange (ETDEWEB)

    Khawaja, Ranish Deedar Ali; Singh, Sarabjeet; Otrakji, Alexi; Padole, Atul; Lim, Ruth; Nimkin, Katherine; Westra, Sjirk; Kalra, Mannudeep K.; Gee, Michael S. [MGH Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States)

    2015-07-15

    Dose reduction in children undergoing CT scanning is an important priority for the radiology community and public at large. Drawbacks of radiation reduction are increased image noise and artifacts, which can affect image interpretation. Iterative reconstruction techniques have been developed to reduce noise and artifacts from reduced-dose CT examinations, although reconstruction algorithm, magnitude of dose reduction and effects on image quality vary. We review the reconstruction principles, radiation dose potential and effects on image quality of several iterative reconstruction techniques commonly used in clinical settings, including 3-D adaptive iterative dose reduction (AIDR-3D), adaptive statistical iterative reconstruction (ASIR), iDose, sinogram-affirmed iterative reconstruction (SAFIRE) and model-based iterative reconstruction (MBIR). We also discuss clinical applications of iterative reconstruction techniques in pediatric abdominal CT. (orig.)

  15. A Monte Carlo study of macroscopic and microscopic dose descriptors for kilovoltage cellular dosimetry

    Science.gov (United States)

    Oliver, P. A. K.; Thomson, Rowan M.

    2017-02-01

    This work investigates how doses to cellular targets depend on cell morphology, as well as relations between cellular doses and doses to bulk tissues and water. Multicellular models of five healthy and cancerous soft tissues are developed based on typical values of cell compartment sizes, elemental compositions and number densities found in the literature. Cells are modelled as two concentric spheres with nucleus and cytoplasm compartments. Monte Carlo simulations are used to calculate the absorbed dose to the nucleus and cytoplasm for incident photon energies of 20-370 keV, relevant for brachytherapy, diagnostic radiology, and out-of-field radiation in higher-energy external beam radiotherapy. Simulations involving cell clusters, single cells and single nuclear cavities are carried out for cell radii between 5 and 10~μ m, and nuclear radii between 2 and 9~μ m. Seven nucleus and cytoplasm elemental compositions representative of animal cells are considered. The presence of a cytoplasm, extracellular matrix and surrounding cells can affect the nuclear dose by up to 13 % . Differences in cell and nucleus size can affect dose to the nucleus (cytoplasm) of the central cell in a cluster of 13 cells by up to 13 % (8 % ). Furthermore, the results of this study demonstrate that neither water nor bulk tissue are reliable substitutes for subcellular targets for incident photon energies  <50 keV: nuclear (cytoplasm) doses differ from dose-to-medium by up to 32 % (18 % ), and from dose-to-water by up to 21 % (8 % ). The largest differences between dose descriptors are seen for the lowest incident photon energies; differences are less than 3 % for energies ≥slant 90 keV. The sensitivity of results with regard to the parameters of the microscopic tissue structure model and cell model geometry, and the importance of the nucleus and cytoplasm as targets for radiation-induced cell death emphasize the importance of accurate models for cellular dosimetry studies.

  16. Photon dose conversion coefficients for the human teeth in standard irradiation geometries

    Energy Technology Data Exchange (ETDEWEB)

    Ulanovsky, A; Wieser, A; Zankl, M; Jacob, P

    2005-07-01

    Photon dose conversion coefficients for the human tooth materials are computed in energy range from 0.01 to 10 MeV by the Monte Carlo method. The voxel phantom Golem of the human body with newly defined tooth region and a modified version of the EGS4 code have been used to compute the coefficients for 30 tooth cells with different locations and materials. The dose responses are calculated for cells representing buccal and lingual enamel layers. The computed coefficients demonstrate a strong dependence on energy and geometry of the radiation source and a weaker dependence on location of the enamel voxels. For isotropic and rotational radiation fields the enamel dose does not show a significant dependence on tooth sample locations. The computed coefficients are used to convert from absorbed dose in teeth to organ dose or to integral air kerma. Examples of integral conversion factors from enamel dose to air kerma are given for several photon fluences specific for the Mayak reprocessing plant in Russia. The integral conversion factors are strongly affected by the energy and angular distributions of photon fluence, which are important characteristics of an exposure scenario for reconstruction of individual occupational doses. (orig.)

  17. Skin dose mapping for fluoroscopically guided interventions.

    Science.gov (United States)

    Johnson, Perry B; Borrego, David; Balter, Stephen; Johnson, Kevin; Siragusa, Daniel; Bolch, Wesley E

    2011-10-01

    To introduce a new skin dose mapping software system for interventional fluoroscopy dose assessment and to analyze the benefits and limitations of patient-phantom matching. In this study, a new software system was developed for visualizing patient skin dose during interventional fluoroscopy procedures. The system works by translating the reference point air kerma to the location of the patient's skin, which is represented by a computational model. In order to orient the model with the x-ray source, geometric parameters found within the radiation dose structured report (RDSR) are used along with a limited number of in-clinic measurements. The output of the system is a visual indication of skin dose mapped onto an anthropomorphic model at a resolution of 5 mm. In order to determine if patient-dependent and patient-sculpted models increase accuracy, peak skin dose was calculated for each of 26 patient-specific models and compared with doses calculated using an elliptical stylized model, a reference hybrid model, a matched patient-dependent model and one patient-sculpted model. Results were analyzed in terms of a percent difference using the doses calculated using the patient-specific model as the true standard. Anthropometric matching, including the use of both patient-dependent and patient-sculpted phantoms, was shown most beneficial for left lateral and anterior-posterior projections. In these cases, the percent difference using a reference model was between 8 and 20%, using a patient-dependent model between 7 and 15%, and using a patient-sculpted model between 3 and 7%. Under the table tube configurations produced errors less than 5% in most situations due to the flattening affects of the table and pad, and the fact that table height is the main determination of source-to-skin distance for these configurations. In addition to these results, several skin dose maps were produced and a prototype display system was placed on the in-clinic monitor of an interventional

  18. Intravenously administered oxotremorine and atropine, in doses known to affect pain threshold, affect the intraspinal release of acetylcholine in rats

    DEFF Research Database (Denmark)

    Abelson, Klas S P; Höglund, A Urban

    2002-01-01

    muscarinic agonists and antagonists modify nociceptive threshold by affecting intraspinal release of acetylcholine (ACh). Catheters were inserted into the femoral vein in rats maintained on isoflurane anaesthesia for administration of oxotremorine (10-300 microg/kg) and atropine (0.1, 10, 5000 microg...

  19. An investigation of the interactions of low doses of ionising radiation and chemical pollutants on Artemia Salina

    International Nuclear Information System (INIS)

    Danova, D.; Benova, K.; Hromada, R.; Falis, M.; Dvorak, P.

    2004-01-01

    Nuclear reactor failures present a risk of global contamination which can be affected by other environmental factors, such as chemicals. The present study has investigated the effect of low doses of gamma radiation in relation to the presence of low doses of Cr and Cd. (authors)

  20. Effect of low doses of gamma radiation on barley tolerance grown under saline conditions

    International Nuclear Information System (INIS)

    Charbaji, T.; Khalifa, Kh; Al-Ain, F.

    2003-01-01

    A field experiment was conducted at Al-Hijanah, an area located at about 35 km south east of Damascus. Seeds of two barley varieties [White Arabi (WA) and Pakistani 30163 (PK) were irradiated with 2 doses 0 and 15 Gy of gamma irradiation. Then, they were shown on salty soil (17.6-18,9 m mos/cm) and irrigated with salty water (5.12-5.75 m mos/cm). A dose of 15 Gy of gamma irradiation was shown to positively affect the percent germination of PK but had no similar effect on WA. The results were obtained at 3 different growth stages: first, the heading stage, 15 Gy dose increased shoots dry weight, Mg ++ , P content and percent of WA, whereas N percent of PK was decreased. When the seeds were irradiated by the same dose. K + content in WA was significantly higher than that in PK. Second, physiological maturity stage, the same dose (15 Gy) increased shoot dry, but affected negatively K + and Na + contents in PK variety. As for WA variety, Mg ++ and P contents were increased, whereas Na + and Cl - were slightly decreased. Third, harvest stage, gamma irradiation had a positive effect on total yield, grain yield, nitrogen yield and harvest index of PK variety. A positive effect was produced on straw yield, 1000-grain weight, and nitrogen yield of WA variety. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-08-01

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

  2. Absorbed dose in CT. Comparison by CT dose index

    International Nuclear Information System (INIS)

    Yamamoto, Kenji; Akazawa, Hiroshi; Andou, Takashi

    2002-01-01

    Few reports have discussed the absorbed dose on CT units with increased scanning capacity even with the current widespread adoption of multi-slice CT units. To compare and investigate the dose indexes among CT units, we measured the absorbed dose on CT units operating in Nagano Prefecture Japan. The measurements showed proportionality between phantom absorbed dose and the exposured mAs values in conventional scanning operation. Further, the measurements showed that the absorbed dose in the center of the phantom differed by about 2.1-fold between the highest and lowest levels on individual CT units. Within a single company, multi-slice CT units of the same company gave absorbed doses of about 1.3 to 1.5 times those of conventional single-slice CT units under the same exposured conditions of conventional scanning. When the scanning pitch was reduced in helical scanning, the absorbed dose at the center of the phantom increased. (author)

  3. Influencia de doses de potássio nos teores de macronutrientes em plantas e sementes de alface Macronutrient content in lettuce affected by potassium side dressing

    Directory of Open Access Journals (Sweden)

    Cristiaini Kano

    2010-09-01

    Full Text Available Avaliou-se a influência de doses de potássio aplicadas em cobertura nos teores de nutrientes em plantas de alface cultivada para produção de sementes. O delineamento experimental utilizado foi blocos casualizados, com cinco tratamentos (0,0; 1,0; 1,5; 2,0 e 2,5 g planta-1 de K2O e seis repetições. Os dados foram submetidos à análise de variância e à análise de regressão. Somente os teores de potássio e magnésio determinados na matéria seca da parte aérea das plantas foram influenciados significativamente pelas doses de potássio testadas, em que para o teor de potássio ocorreu aumento linear e para o de magnésio houve redução também linear. Conclui-se que os tratamentos testados não interferiram de forma significativa nos teores de macronutrientes das sementes, apesar de ter modificado os teores de potássio e de magnésio na matéria seca da parte aérea das plantas de alface, cultivar Verônica.The influence of potassium rates applied in side dressing was evaluated on the nutrient content of lettuce plants cultivated for seed production. The experiment was carried out in randomized complete blocks, with five treatments (0.0; 1.0; 1.5; 2.0 and 2.5 g plant-1 of K2O and six replications. Only the potassium and the magnesium content in the dry matter of the plant aboveground part was affected by the treatments. The potassium content increased and the magnesium content decreased, both linearly, as an effect of the application of increasing potassium rates. Also, despite of the effect on the plant potassium content, the treatments did not affect the seed macronutrient content.

  4. Bisphenol A (BPA) aggravates multiple low-dose streptozotocin-induced Type 1 diabetes in C57BL/6 mice.

    Science.gov (United States)

    Cetkovic-Cvrlje, Marina; Thinamany, Sinduja; Bruner, Kylie A

    2017-12-01

    Type 1 diabetes (T1D) is a T-cell-mediated autoimmune disorder characterized by destruction of insulin-producing pancreatic β-cells. Whereas epidemiological data implicate environmental factors in the increasing incidence of T1D, their identity remains unknown. Though exposure to bisphenol A (BPA) has been associated with several disorders, no epidemiologic evidence has linked BPA exposure and T1D. The goal of this study was to elucidate diabetogenic potentials of BPA and underlying mechanisms in the context of T-cell immunity, in a multiple low-dose streptozotocin (MLDSTZ)-induced autoimmune mouse T1D model. C57BL/6 mice were orally exposed to 1 or 10 mg BPA/L starting at 4 wk of age; diabetes was induced at 9 wk of age with STZ. T-cell composition, function, and insulitis levels were studied at Days 11 and 50 during diabetes development (i.e. post-first STZ injection). Results showed both BPA doses increased diabetes incidence and affected T-cell immunity. However, mechanisms of diabetogenic action appeared divergent based on dose. Low-dose BPA fits a profile of an agent that exhibits pro-diabetogenic effects via T-cell immunomodulation in the early stages of disease development, i.e. decreases in splenic T-cell subpopulations [especially CD4 + T-cells] along with a trend in elevation of splenic T-cell formation of pro-inflammatory cytokines (IFN-γ, TNF-α, and IL-6). In contrast, high-dose BPA did not affect T-cell populations and led to decreased levels of IFN-γ and TNF-α. Both treatments did not affect insulitis levels at the disease early stage, but aggravated it later on. By the study end, besides decreasing T-cell proliferative capacity, low-dose BPA did not affect other T-cell-related parameters, including cytokine secretion, comparable to the effects of high-dose BPA. In conclusion, this study confirmed BPA as a potential diabetogenic compound with immunomodulatory mechanisms of action - in the context of T-cell immunity - that seemed to be dose

  5. Laser-based irradiation apparatus and methods for monitoring the dose-rate response of semiconductor devices

    Science.gov (United States)

    Horn, Kevin M [Albuquerque, NM

    2006-03-28

    A scanned, pulsed, focused laser irradiation apparatus can measure and image the photocurrent collection resulting from a dose-rate equivalent exposure to infrared laser light across an entire silicon die. Comparisons of dose-rate response images or time-delay images from before, during, and after accelerated aging of a device, or from periodic sampling of devices from fielded operational systems allows precise identification of those specific age-affected circuit structures within a device that merit further quantitative analysis with targeted materials or electrical testing techniques. Another embodiment of the invention comprises a broad-beam, dose rate-equivalent exposure apparatus. The broad-beam laser irradiation apparatus can determine if aging has affected the device's overall functionality. This embodiment can be combined with the synchronized introduction of external electrical transients into a device under test to simulate the electrical effects of the surrounding circuitry's response to a radiation exposure.

  6. Comparison of doses, before and after remedial action

    International Nuclear Information System (INIS)

    Wallo, A. III

    1988-01-01

    The Division of Facility and Site Decommissioning Projects at DOE-Headquarters is evaluating potential doses from vicinity properties before and after remedial action at several sites using the RESRAD computer code. A preliminary review was completed for nineteen Colonie vicinity properties. This review indicated potential doses before remedial action at these sites ranged from about 43 to 2 mrem/year and after remediation between 5 and 0 mrem/year. These estimates indicate the conservatism in the DOE-derived soil decontamination remedial action. Following remedial action, the potential doses are on the order of those being considered to be below regulatory concern by EPA and NRC. The estimates made for these sites are still conservative due to the method used to determine the source term. More realistic assessments of source terms are anticipate dot significantly affect the after-remedial-action doses, possibly lowering them all to below 1 mrem/year. This evaluation is being refined with more realistic estimates of the source term, for all of the Colonie vicinity properties. Once the Colonie vicinity properties are completed, at least three other sites will be evaluated. It is hoped that this information will provide added confidence in the remedial action guidelines and more general acceptance of the guidelines by the EPA and others

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  8. Time improvement of photoelectric effect calculation for absorbed dose estimation

    International Nuclear Information System (INIS)

    Massa, J M; Wainschenker, R S; Doorn, J H; Caselli, E E

    2007-01-01

    Ionizing radiation therapy is a very useful tool in cancer treatment. It is very important to determine absorbed dose in human tissue to accomplish an effective treatment. A mathematical model based on affected areas is the most suitable tool to estimate the absorbed dose. Lately, Monte Carlo based techniques have become the most reliable, but they are time expensive. Absorbed dose calculating programs using different strategies have to choose between estimation quality and calculating time. This paper describes an optimized method for the photoelectron polar angle calculation in photoelectric effect, which is significant to estimate deposited energy in human tissue. In the case studies, time cost reduction nearly reached 86%, meaning that the time needed to do the calculation is approximately 1/7 th of the non optimized approach. This has been done keeping precision invariant

  9. Influence of a transverse magnetic field on the dose deposited by a 6 MV linear accelerator

    Directory of Open Access Journals (Sweden)

    Richter Sebastian

    2017-09-01

    Full Text Available An integrated system of a linear accelerator and a magnetic resonance imaging (MRI device may provide real-time imaging during radiotherapy treatments. This work investigated changes affecting the dose deposition caused by a magnetic field (B-field transverse to the beam direction by means of Monte Carlo simulations. Two different phantoms were used: A water phantom (Ph1 and a water-air phantom (Ph2 with a 4-2-4 cm water-air-water cross section. Dose depositions were scored for B-field values of 0 T, 0.35 T, 0.5 T, 1.5 T, 3 T and 5 T. Beams were based on a precalculated photon spectrum taken from an earlier simulated Elekta 6 MV FFF accelerator. All lateral profiles in Ph1 showed a Lorentz force driven shift w.r.t. the B-field strength, presenting a steeper penumbra in the shift's direction. Depositions were shifted up to 0.3 cm for 5 T, showing a constant central axis plateau-dose or an increase by 2.3 % for small fields. Depth-dose curves in Ph1 showed a shift of the dose maximum towards the beam entrance direction for increasing B-field of up to 1.1 cm; the maximum dose was increased by 6.9 %. In Ph2, an asymmetric dose increase by up to 36.9 % was observed for 1.5 T at the water-air boundary, resulting from the electron return effect (ERE. In our scenario, B-field dependent dose shifts and local build-ups were observed, which consequently affect the resulting dose distribution and need to be considered in magnetic resonance guided radiotherapy treatment planning.

  10. TU-F-9A-01: Balancing Image Quality and Dose in Radiography

    International Nuclear Information System (INIS)

    Peck, D; Pasciak, A

    2014-01-01

    Emphasis is often placed on minimizing radiation dose in diagnostic imaging without a complete consideration of the effect on image quality, especially those that affect diagnostic accuracy. This session will include a patient image-based review of diagnostic quantities important to radiologists in conventional radiography, including the effects of body habitus, age, positioning, and the clinical indication of the exam. The relationships between image quality, radiation dose, and radiation risk will be discussed, specifically addressing how these factors are affected by image protocols and acquisition parameters and techniques. This session will also discuss some of the actual and perceived radiation risk associated with diagnostic imaging. Regardless if the probability for radiation-induced cancer is small, the fear associated with radiation persists. Also when a risk has a benefit to an individual or to society, the risk may be justified with respect to the benefit. But how do you convey the risks and the benefits to people? This requires knowledge of how people perceive risk and how to communicate the risk and the benefit to different populations. In this presentation the sources of errors in estimating risk from radiation and some methods used to convey risks are reviewed. Learning Objectives: Understand the image quality metrics that are clinically relevant to radiologists. Understand how acquisition parameters and techniques affect image quality and radiation dose in conventional radiology. Understand the uncertainties in estimates of radiation risk from imaging exams. Learn some methods for effectively communicating radiation risk to the public

  11. TU-F-9A-01: Balancing Image Quality and Dose in Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Peck, D [Henry Ford Health System, Detroit, MI (United States); Pasciak, A [University of Tennessee Medical Center, Knoxville, TN (United States)

    2014-06-15

    Emphasis is often placed on minimizing radiation dose in diagnostic imaging without a complete consideration of the effect on image quality, especially those that affect diagnostic accuracy. This session will include a patient image-based review of diagnostic quantities important to radiologists in conventional radiography, including the effects of body habitus, age, positioning, and the clinical indication of the exam. The relationships between image quality, radiation dose, and radiation risk will be discussed, specifically addressing how these factors are affected by image protocols and acquisition parameters and techniques. This session will also discuss some of the actual and perceived radiation risk associated with diagnostic imaging. Regardless if the probability for radiation-induced cancer is small, the fear associated with radiation persists. Also when a risk has a benefit to an individual or to society, the risk may be justified with respect to the benefit. But how do you convey the risks and the benefits to people? This requires knowledge of how people perceive risk and how to communicate the risk and the benefit to different populations. In this presentation the sources of errors in estimating risk from radiation and some methods used to convey risks are reviewed. Learning Objectives: Understand the image quality metrics that are clinically relevant to radiologists. Understand how acquisition parameters and techniques affect image quality and radiation dose in conventional radiology. Understand the uncertainties in estimates of radiation risk from imaging exams. Learn some methods for effectively communicating radiation risk to the public.

  12. What is correct: equivalent dose or dose equivalent

    International Nuclear Information System (INIS)

    Franic, Z.

    1994-01-01

    In Croatian language some physical quantities in radiation protection dosimetry have not precise names. Consequently, in practice either terms in English or mathematical formulas are used. The situation is even worse since the Croatian language only a limited number of textbooks, reference books and other papers are available. This paper compares the concept of ''dose equivalent'' as outlined in International Commission on Radiological Protection (ICRP) recommendations No. 26 and newest, conceptually different concept of ''equivalent dose'' which is introduced in ICRP 60. It was found out that Croatian terminology is both not uniform and unprecise. For the term ''dose equivalent'' was, under influence of Russian and Serbian languages, often used as term ''equivalent dose'' even from the point of view of ICRP 26 recommendations, which was not justified. Unfortunately, even now, in Croatia the legal unit still ''dose equivalent'' defined as in ICRP 26, but the term used for it is ''equivalent dose''. Therefore, in Croatian legislation a modified set of quantities introduced in ICRP 60, should be incorporated as soon as possible

  13. Relative effect of radiation dose rate on hemopoietic and nonhemopoietic lethality of total-body irradiation

    International Nuclear Information System (INIS)

    Peters, L.J.; McNeill, J.; Karolis, C.; Thames, H.D. Jr.; Travis, E.L.

    1986-01-01

    Experiments were undertaken to determine the influence of dose rate on the toxicity of total-body irrdiation (TBI) with and without syngeneic bone-marrow rescue in mice. The results showed a much greater dose-rate dependence for death from nonhemopoietic toxicity than from bone-marrow ablation, with the ratio of LD 50 's increasing from 1.73 at 25 cGy/min to 2.80 at 1 cGy/min. At the higher dose rates, dose-limiting nonhemopoietic toxicity resulted from late organ injury, affecting the lungs, kidneys, and liver. At 1 cGy/min the major dose-limiting nonhemopoietic toxicity was acute gastrointestinal injury. The implications of these results in the context of TBI in preparation for bone-marrow transplantation are discussed. 15 refs., 4 figs

  14. Outcome of stroke patients receiving different doses of recombinant tissue plasminogen activator.

    Science.gov (United States)

    Ong, Cheung-Ter; Wong, Yi-Sin; Wu, Chi-Shun; Su, Yu-Hsiang

    2017-01-01

    Intravenous recombinant tissue plasminogen activator (tPA) at a dose of 0.9 mg/kg body weight is associated with a high hemorrhagic transformation (HT) rate. Low-dose tPA (0.6 mg/kg) may have a lower hemorrhage rate but the mortality and disability rates at 90 days cannot be confirmed as non-inferior to standard-dose tPA. Whether the doses 0.7 and 0.8 mg/kg have better efficacy and safety needs further investigation. Therefore, this study is to compare the efficacy and safety of each dose of tPA (0.6, 0.7, 0.8, and 0.9 mg/kg body weight) and to investigate the factors affecting early neurological improvement (ENI) and early neurological deterioration (END). For this observational study, data were obtained from 274 patients who received tPA thrombolytic therapy in Chia-Yi Christian Hospital stroke unit. The tPA dose was given at the discretion of each physician. The definition of ENI was a >8 point improvement (compared with baseline) at 24 h following thrombolytic therapy or an improvement in the National Institutes of Health Stroke Score (NIHSS) to 0 or 1 toward the end of tPA infusion. The definition of END was a >4 point increase in NIHSS (compared with baseline) within 24 h of tPA infusion. The primary objective was to investigate whether 0.7 and 0.8 mg/kg of tPA have higher ENI rate, lower END rate, and better outcome at 6 months. Poor outcome was defined as having a modified Rankin Scale of 3 to 6 (range, 0 [no symptoms] to 6 [death]). The secondary objective was to investigate whether low-dose tPA has a lower risk of intracerebral HT than that with standard-dose tPA. We also investigated the factors affecting ENI, END, HT, and 6-month outcome. A total of 274 patients were included during the study period, of whom 260 were followed up for >6 months. There was a trend for the HT rate to increase as the dose increased ( P =0.02). The symptomatic HT rate was not significantly different among the low-dose and standard-dose groups. The ENI and END ( P =0.52) were

  15. Dose-Escalation Study for Cardiac Radiosurgery in a Porcine Model

    Energy Technology Data Exchange (ETDEWEB)

    Blanck, Oliver, E-mail: oliver.blanck@uksh.de [Department of Radiation Oncology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); CyberKnife Center Northern Germany, Guestrow (Germany); Bode, Frank [Medical Department II, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Gebhard, Maximilian [Institute of Pathology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Hunold, Peter [Department of Radiology and Nuclear Medicine, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Brandt, Sebastian [Department of Anaesthesiology and Intensive Care Medicine, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Bruder, Ralf [Institute for Robotics and Cognitive Systems, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Grossherr, Martin [Department of Anaesthesiology and Intensive Care Medicine, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Vonthein, Reinhard [Institute of Medical Biometry and Statistics, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Rades, Dirk [Department of Radiation Oncology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Dunst, Juergen [Department of Radiation Oncology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); University Copenhagen (Denmark)

    2014-07-01

    Purpose: To perform a proof-of-principle dose-escalation study to radiosurgically induce scarring in cardiac muscle tissue to block veno-atrial electrical connections at the pulmonary vein antrum, similar to catheter ablation. Methods and Materials: Nine mini-pigs underwent pretreatment magnetic resonance imaging (MRI) evaluation of heart function and electrophysiology assessment by catheter measurements in the right superior pulmonary vein (RSPV). Immediately after examination, radiosurgery with randomized single-fraction doses of 0 and 17.5-35 Gy in 2.5-Gy steps were delivered to the RSPV antrum (target volume 5-8 cm{sup 3}). MRI and electrophysiology were repeated 6 months after therapy, followed by histopathologic examination. Results: Transmural scarring of cardiac muscle tissue was noted with doses ≥32.5 Gy. However, complete circumferential scarring of the RSPV was not achieved. Logistic regressions showed that extent and intensity of fibrosis significantly increased with dose. The 50% effective dose for intense fibrosis was 31.3 Gy (odds ratio 2.47/Gy, P<.01). Heart function was not affected, as verified by MRI and electrocardiogram evaluation. Adjacent critical structures were not damaged, as verified by pathology, demonstrating the short-term safety of small-volume cardiac radiosurgery with doses up to 35 Gy. Conclusions: Radiosurgery with doses >32.5 Gy in the healthy pig heart can induce circumscribed scars at the RSPV antrum noninvasively, mimicking the effect of catheter ablation. In our study we established a significant dose-response relationship for cardiac radiosurgery. The long-term effects and toxicity of such high radiation doses need further investigation in the pursuit of cardiac radiosurgery for noninvasive treatment of atrial fibrillation.

  16. Interactive dose shaping - efficient strategies for CPU-based real-time treatment planning

    International Nuclear Information System (INIS)

    Ziegenhein, P; Kamerling, C P; Oelfke, U

    2014-01-01

    Conventional intensity modulated radiation therapy (IMRT) treatment planning is based on the traditional concept of iterative optimization using an objective function specified by dose volume histogram constraints for pre-segmented VOIs. This indirect approach suffers from unavoidable shortcomings: i) The control of local dose features is limited to segmented VOIs. ii) Any objective function is a mathematical measure of the plan quality, i.e., is not able to define the clinically optimal treatment plan. iii) Adapting an existing plan to changed patient anatomy as detected by IGRT procedures is difficult. To overcome these shortcomings, we introduce the method of Interactive Dose Shaping (IDS) as a new paradigm for IMRT treatment planning. IDS allows for a direct and interactive manipulation of local dose features in real-time. The key element driving the IDS process is a two-step Dose Modification and Recovery (DMR) strategy: A local dose modification is initiated by the user which translates into modified fluence patterns. This also affects existing desired dose features elsewhere which is compensated by a heuristic recovery process. The IDS paradigm was implemented together with a CPU-based ultra-fast dose calculation and a 3D GUI for dose manipulation and visualization. A local dose feature can be implemented via the DMR strategy within 1-2 seconds. By imposing a series of local dose features, equal plan qualities could be achieved compared to conventional planning for prostate and head and neck cases within 1-2 minutes. The idea of Interactive Dose Shaping for treatment planning has been introduced and first applications of this concept have been realized.

  17. Dose volume assessment of high dose rate 192IR endobronchial implants

    International Nuclear Information System (INIS)

    Cheng, B. Saw; Korb, Leroy J.; Pawlicki, Todd; Wu, Andrew

    1996-01-01

    Purpose: To study the dose distributions of high dose rate (HDR) endobronchial implants using the dose nonuniformity ratio (DNR) and three volumetric irradiation indices. Methods and Materials: Multiple implants were configured by allowing a single HDR 192 Ir source to step through a length of 6 cm along an endobronchial catheter. Dwell times were computed to deliver a dose of 5 Gy to points 1 cm away from the catheter axis. Five sets of source configurations, each with different dwell position spacings from 0.5 to 3.0 cm, were evaluated. Three-dimensional (3D) dose distributions were then generated for each source configuration. Differential and cumulative dose-volume curves were generated to quantify the degree of target volume coverage, dose nonuniformity within the target volume, and irradiation of tissues outside the target volume. Evaluation of the implants were made using the DNR and three volumetric irradiation indices. Results: The observed isodose distributions were not able to satisfy all the dose constraints. The ability to optimally satisfy the dose constraints depended on the choice of dwell position spacing and the specification of the dose constraint points. The DNR and irradiation indices suggest that small dwell position spacing does not result in a more homogeneous dose distribution for the implant. This study supports the existence of a relationship between the dwell position spacing and the distance from the catheter axis to the reference dose or dose constraint points. Better dose homogeneity for an implant can be obtained if the spacing of the dwell positions are about twice the distance from the catheter axis to the reference dose or dose constraint points

  18. Optimisation of antimicrobial dosing based on pharmacokinetic and pharmacodynamic principles

    Directory of Open Access Journals (Sweden)

    Grace Si Ru Hoo

    2017-01-01

    Full Text Available While suboptimal dosing of antimicrobials has been attributed to poorer clinical outcomes, clinical cure and mortality advantages have been demonstrated when target pharmacokinetic (PK and pharmacodynamic (PD indices for various classes of antimicrobials were achieved to maximise antibiotic activity. Dosing optimisation requires a good knowledge of PK/PD principles. This review serves to provide a foundation in PK/PD principles for the commonly prescribed antibiotics (β-lactams, vancomycin, fluoroquinolones and aminoglycosides, as well as dosing considerations in special populations (critically ill and obese patients. PK principles determine whether an appropriate dose of antimicrobial reaches the intended pathogen(s. It involves the fundamental processes of absorption, distribution, metabolism and elimination, and is affected by the antimicrobial's physicochemical properties. Antimicrobial pharmacodynamics define the relationship between the drug concentration and its observed effect on the pathogen. The major indicator of the effect of the antibiotics is the minimum inhibitory concentration. The quantitative relationship between a PK and microbiological parameter is known as a PK/PD index, which describes the relationship between dose administered and the rate and extent of bacterial killing. Improvements in clinical outcomes have been observed when antimicrobial agents are dosed optimally to achieve their respective PK/PD targets. With the rising rates of antimicrobial resistance and a limited drug development pipeline, PK/PD concepts can foster more rational and individualised dosing regimens, improving outcomes while simultaneously limiting the toxicity of antimicrobials.

  19. Thyroid doses for evacuees from the Fukushima nuclear accident

    Science.gov (United States)

    Tokonami, Shinji; Hosoda, Masahiro; Akiba, Suminori; Sorimachi, Atsuyuki; Kashiwakura, Ikuo; Balonov, Mikhail

    2012-07-01

    A primary health concern among residents and evacuees in affected areas immediately after a nuclear accident is the internal exposure of the thyroid to radioiodine, particularly I-131, and subsequent thyroid cancer risk. In Japan, the natural disasters of the earthquake and tsunami in March 2011 destroyed an important function of the Fukushima Daiichi Nuclear Power Plant (F1-NPP) and a large amount of radioactive material was released to the environment. Here we report for the first time extensive measurements of the exposure to I-131 revealing I-131 activity in the thyroid of 46 out of the 62 residents and evacuees measured. The median thyroid equivalent dose was estimated to be 4.2 mSv and 3.5 mSv for children and adults, respectively, much smaller than the mean thyroid dose in the Chernobyl accident (490 mSv in evacuees). Maximum thyroid doses for children and adults were 23 mSv and 33 mSv, respectively.

  20. Absorbed doses to the main parts of eyeball due to use 90Sr + 90Y ophthalmic applicator

    International Nuclear Information System (INIS)

    Chen Lishu

    1993-05-01

    The ophthalmic radiotherapy dosimetry and some affecting factors are introduced. The distributions of absorbed doses to the main parts of a fresh eyeball such as the cornea, sclera, lens and anterior chamber, during the radiotherapy by using a 90 Sr + 90 Y ophthalmic applicator are presented. An tissue-equivalent extrapolation ionization chamber was used in the dose measurement. The reasonable doses during ophthalmic radiotherapy for different depths have been obtained. Therefore, the absorbed dose to the lens, the most sensitive organ, can be given. These data are useful for radiation protection in ophthalmic radiotherapy

  1. Correlation-study about the ambient dose rate and the weather conditions

    Science.gov (United States)

    Furuya, Masato; Hatano, Yuko; Aoyama, Tomoo; Igarashi, Yasuhito; Kita, Kazuyuki; Ishizuka, Masahide

    2016-04-01

    The long-term radiation risks are believed to be heavily affected by the resuspension process. We therefore focus on the surface-atmosphere exchange process of released radioactive materials in this study. Radioactive materials were deposited on the soil and float in the air, and such complicated process are influenced by the weather conditions deeply. We need to reveal the correlation between the weather conditions and the ambient dose rate. In this study, we study the correlation between the weather conditions and the ambient dose rate with the correction of the decrease due to the radioactive decay. We found that there is a negative correlation between the ambient dose rate and the soil water content by the correlation coefficient. Using this result, we reconstruct the ambient dose rate from the weather conditions by the multiple regression analysis and found that the reconstructed data agree with the observation very well. Using Kalman filter, which can be sequentially updates the state estimate, we obtained such a good agreement.

  2. A novel dose uncertainty model and its application for dose verification

    International Nuclear Information System (INIS)

    Jin Hosang; Chung Heetaek; Liu Chihray; Palta, Jatinder; Suh, Tae-Suk; Kim, Siyong

    2005-01-01

    Based on statistical approach, a novel dose uncertainty model was introduced considering both nonspatial and spatial dose deviations. Non-space-oriented uncertainty is mainly caused by dosimetric uncertainties, and space-oriented dose uncertainty is the uncertainty caused by all spatial displacements. Assuming these two parts are independent, dose difference between measurement and calculation is a linear combination of nonspatial and spatial dose uncertainties. Two assumptions were made: (1) the relative standard deviation of nonspatial dose uncertainty is inversely proportional to the dose standard deviation σ, and (2) the spatial dose uncertainty is proportional to the gradient of dose. The total dose uncertainty is a quadratic sum of the nonspatial and spatial uncertainties. The uncertainty model provides the tolerance dose bound for comparison between calculation and measurement. In the statistical uncertainty model based on a Gaussian distribution, a confidence level of 3σ theoretically confines 99.74% of measurements within the bound. By setting the confidence limit, the tolerance bound for dose comparison can be made analogous to that of existing dose comparison methods (e.g., a composite distribution analysis, a γ test, a χ evaluation, and a normalized agreement test method). However, the model considers the inherent dose uncertainty characteristics of the test points by taking into account the space-specific history of dose accumulation, while the previous methods apply a single tolerance criterion to the points, although dose uncertainty at each point is significantly different from others. Three types of one-dimensional test dose distributions (a single large field, a composite flat field made by two identical beams, and three-beam intensity-modulated fields) were made to verify the robustness of the model. For each test distribution, the dose bound predicted by the uncertainty model was compared with simulated measurements. The simulated

  3. A dose error evaluation study for 4D dose calculations

    Science.gov (United States)

    Milz, Stefan; Wilkens, Jan J.; Ullrich, Wolfgang

    2014-10-01

    Previous studies have shown that respiration induced motion is not negligible for Stereotactic Body Radiation Therapy. The intrafractional breathing induced motion influences the delivered dose distribution on the underlying patient geometry such as the lung or the abdomen. If a static geometry is used, a planning process for these indications does not represent the entire dynamic process. The quality of a full 4D dose calculation approach depends on the dose coordinate transformation process between deformable geometries. This article provides an evaluation study that introduces an advanced method to verify the quality of numerical dose transformation generated by four different algorithms. The used transformation metric value is based on the deviation of the dose mass histogram (DMH) and the mean dose throughout dose transformation. The study compares the results of four algorithms. In general, two elementary approaches are used: dose mapping and energy transformation. Dose interpolation (DIM) and an advanced concept, so called divergent dose mapping model (dDMM), are used for dose mapping. The algorithms are compared to the basic energy transformation model (bETM) and the energy mass congruent mapping (EMCM). For evaluation 900 small sample regions of interest (ROI) are generated inside an exemplary lung geometry (4DCT). A homogeneous fluence distribution is assumed for dose calculation inside the ROIs. The dose transformations are performed with the four different algorithms. The study investigates the DMH-metric and the mean dose metric for different scenarios (voxel sizes: 8 mm, 4 mm, 2 mm, 1 mm 9 different breathing phases). dDMM achieves the best transformation accuracy in all measured test cases with 3-5% lower errors than the other models. The results of dDMM are reasonable and most efficient in this study, although the model is simple and easy to implement. The EMCM model also achieved suitable results, but the approach requires a more complex

  4. Standardization of high-dose measurement of electron and gamma ray absorbed doses and dose rates

    International Nuclear Information System (INIS)

    McLaughlin, W.L.

    1985-01-01

    Intense electron beams and gamma radiation fields are used for sterilizing medical devices, treating municipal wastes, processing industrial goods, controlling parasites and pathogens, and extending the shelf-life of foods. Quality control of such radiation processes depends largely on maintaining measurement quality assurance through sound dosimetry procedures in the research leading to each process, in the commissioning of that process, and in the routine dose monitoring practices. This affords documentation as to whether satisfactory dose uniformity is maintained throughout the product and throughout the process. Therefore, dosimetry at high doses and dose rates must in many radiation processes be standardized carefully, so that 'dosimetry release' of a product is verified. This standardization is initiated through preliminary dosimetry intercomparison studies such as those sponsored recently by the IAEA. This is followed by establishing periodic exercises in traceability to national or international standards of absorbed dose and dose rate. Traceability is achieved by careful selection of dosimetry methods and proven reference dosimeters capable of giving sufficiently accurate and precise 'transfer' dose assessments: (1) they must be calibrated or have well-established radiation-yield indices; (2) their radiation response characteristics must be reproducible and cover the dose range of interest; (3) they must withstand the rigours of back-and-forth mailing between a central standardizing laboratory and radiation processing facilities, without excessive errors arising due to instabilities, dosimeter batch non-uniformities, and environmental and handling stresses. (author)

  5. On the population dose close to the Semipalatinsk Nuclear Test Site

    International Nuclear Information System (INIS)

    Hill, P.; Peterson, L.; Pivovarov, S.; Rukhin, A.; Seredavina, T.; Sushkova, N.; Artemyev, O.; Abildinova, G.

    2008-01-01

    Full text: As a result of nuclear weapon tests at the Semipalatinsk Nuclear Test Site (SNTS) radiation exposure of inhabitants in surrounding villages has occurred over a period of several decades. Despite a number of published reports the determination of cumulative doses to the associated population and its uncertainty has not been finalized yet. Among the factors complicating this task are a) the time passed, b) the lack of direct personal dosimetry within the population possibly exposed, c) significant migration (out and in), d) inhomogeneous distribution of radionuclide deposition, e) new settlers at the SNTS and f) economic activities at the SNTS. This paper reports on the contribution of the ISTC-project K-465.2 'Complex examination of Semipalatinsk Test Site Region's population by advanced dosimetry methods' in assessing the population dose. The main results have been obtained during a period of three years by using the recent methodological progress made in EPR dosimetry on tooth enamel. Tooth enamel of people from settlements Dolon, Bodene, Cheremushki, Mostik, which were affected mainly by the first atomic explosion 1949, settlement Sarjal, affected by the first thermonuclear explosion in 1953, and as a control village Maysk, where radiological and meteorological records suggest that there was no significant radionuclide deposition near this village despite its position at the borders of SNTS, were investigated. Fresh tooth samples were used, which reflect well the current radiological situation. Additional measurements included e.g. environmental monitoring and in-vivo monitoring. EPR results suggest the existence of two sub-populations with different dose distributions: One with doses in the range of expected values from both natural background and SNTS testing, and another one with still higher doses not explained by the observed radioactive contamination. This finding is rather surprising. Additional research is needed to obtain a better statistic

  6. SU-F-T-59: The Effect of Radiotherapy Dose On Immunoadjuvants

    International Nuclear Information System (INIS)

    Moreau, M; Yasmin-Karim, S; Hao, Y; Ngwa, W

    2016-01-01

    Purpose: Combining radiotherapy with immunotherapy is a promising approach to enhance treatment outcomes for cancer patients. This in-vitro study investigated which radiotherapy doses could adversely affect the function of anti-CD40 mAb, which is one of the key immunoadjuvants under investigations for priming such combination therapy. Methods: Human monocyte derived THP-1 cells were treated with 100ng/mL of PMA in chamber slides to differentiate into macrophage. The THP-1 differentiated macrophages were treated with 2uL/ml of the anti-CD40 mAb and incubated at 37°C and 5% CO2 for 24 hours. Anti-CD40 mAb treated cells were then irradiated at different doses of x-rays: (0, 2, 4, 6, 8, and 12) Gy using the Small Animal Radiotherapy Research Platform (SARRP). After radiation, the cells were left at 4°C for 2 hours followed by immunofluorescence assay. A Nikon inverted live-cell imaging system with fluorescence microscope was used to image the cells mounted on a slide fixed with Dapi. For comparison, an ELISA assay was performed with the antibody added to 3mL of PBS in multiple 10mm dishes. The 10mm dishes were irradiated at different x-ray dose: (0, 2, 4, 6, 8. 10, 12, and 15) Gy using the SARRP. Results: The anti-CD40 mAb activating the macrophages starts to lose their viability due to radiation dose between 8Gy to 12Gy as indicated by the immunofluorescence assay. The ELISA assay, also indicated that such high doses could lead to loss of the mAb’s viability. Conclusion: This work suggests that high doses like those employed during Stereotactic Ablative Radiotherapy may affect the viability of immunoadjuvants such as anti-CD 40. This study avails in-vivo experiments combining radiotherapy with anti-cd40 to get synergistic outcomes, including in the treatment of metastatic disease.

  7. SU-F-T-59: The Effect of Radiotherapy Dose On Immunoadjuvants

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, M [Dana Farber Cancer Institute, Boston, MA (United States); Yasmin-Karim, S [Dana-Farber Cancer Institute, Boston, Massachusetts (United States); Hao, Y [University of Massachusetts Lowell, Lowell, MA (United States); Ngwa, W [Harvard Medical School, Boston, MA (United States)

    2016-06-15

    Purpose: Combining radiotherapy with immunotherapy is a promising approach to enhance treatment outcomes for cancer patients. This in-vitro study investigated which radiotherapy doses could adversely affect the function of anti-CD40 mAb, which is one of the key immunoadjuvants under investigations for priming such combination therapy. Methods: Human monocyte derived THP-1 cells were treated with 100ng/mL of PMA in chamber slides to differentiate into macrophage. The THP-1 differentiated macrophages were treated with 2uL/ml of the anti-CD40 mAb and incubated at 37°C and 5% CO2 for 24 hours. Anti-CD40 mAb treated cells were then irradiated at different doses of x-rays: (0, 2, 4, 6, 8, and 12) Gy using the Small Animal Radiotherapy Research Platform (SARRP). After radiation, the cells were left at 4°C for 2 hours followed by immunofluorescence assay. A Nikon inverted live-cell imaging system with fluorescence microscope was used to image the cells mounted on a slide fixed with Dapi. For comparison, an ELISA assay was performed with the antibody added to 3mL of PBS in multiple 10mm dishes. The 10mm dishes were irradiated at different x-ray dose: (0, 2, 4, 6, 8. 10, 12, and 15) Gy using the SARRP. Results: The anti-CD40 mAb activating the macrophages starts to lose their viability due to radiation dose between 8Gy to 12Gy as indicated by the immunofluorescence assay. The ELISA assay, also indicated that such high doses could lead to loss of the mAb’s viability. Conclusion: This work suggests that high doses like those employed during Stereotactic Ablative Radiotherapy may affect the viability of immunoadjuvants such as anti-CD 40. This study avails in-vivo experiments combining radiotherapy with anti-cd40 to get synergistic outcomes, including in the treatment of metastatic disease.

  8. Dose survival of G0 lymphocytes irradiated in vitro: A test for a possible population bias in the cohort of atomic-bomb survivors exposed to high doses

    International Nuclear Information System (INIS)

    Nakamura, Nori; Sposto, R.; Akiyama, Mitoshi.

    1993-04-01

    An in-vitro colony assay was employed for X-ray dose-survival studies of peripheral-blood lymphocytes from 117 Adult Health Study participants with Dosimetry System 1986 doses 10 values (the X-ray dose required to kill 90% of cells) for these two groups were 3.40 Gy (7.5%) and 3.34 Gy (7.8%), respectively. No statistically significant differences in their distributions were detected. In addition, neither sex nor age affected the in-vitro radiosensitivity of lymphocytes for either group or for all subjects combined. Therefore it was concluded that, as far as the G 0 -lymphocyte colony assay is concerned, there is no evidence for preferential loss of individuals with higher cellular radiosensitivity among the high-dose atomic bomb survivors. However, it should be noted that the interindividual variations in cellular radiosensitivity were not large compared with the experimental variations. Consequently, the above-mentioned results should be considered due to the small heterogeneity of lymphocyte radiosensitivity among the survivors. (J.P.N.)

  9. Biological influence from low dose and low-dose rate radiation

    International Nuclear Information System (INIS)

    Magae, Junji

    2007-01-01

    Although living organisms have defense mechanisms for radioadaptive response, the influence is considered to vary qualitatively and quantitatively for low dose and high dose, as well as for low-dose rate and high-dose rate. This article describes the bioresponse to low dose and low-dose rate. Among various biomolecules, DNA is the most sensitive to radiation, and accurate replication of DNA is an essential requirement for the survival of living organisms. Also, the influence of active enzymes resulted from the effect of radiation on enzymes in the body is larger than the direct influence of radiation on the body. After this, the article describes the carcinogenic risk by low-dose radiation, and then so-called Hormesis effect to create cancer inhibition effect by stimulating active physiology. (S.K.)

  10. Superficial dose evaluation of four dose calculation algorithms

    Science.gov (United States)

    Cao, Ying; Yang, Xiaoyu; Yang, Zhen; Qiu, Xiaoping; Lv, Zhiping; Lei, Mingjun; Liu, Gui; Zhang, Zijian; Hu, Yongmei

    2017-08-01

    Accurate superficial dose calculation is of major importance because of the skin toxicity in radiotherapy, especially within the initial 2 mm depth being considered more clinically relevant. The aim of this study is to evaluate superficial dose calculation accuracy of four commonly used algorithms in commercially available treatment planning systems (TPS) by Monte Carlo (MC) simulation and film measurements. The superficial dose in a simple geometrical phantom with size of 30 cm×30 cm×30 cm was calculated by PBC (Pencil Beam Convolution), AAA (Analytical Anisotropic Algorithm), AXB (Acuros XB) in Eclipse system and CCC (Collapsed Cone Convolution) in Raystation system under the conditions of source to surface distance (SSD) of 100 cm and field size (FS) of 10×10 cm2. EGSnrc (BEAMnrc/DOSXYZnrc) program was performed to simulate the central axis dose distribution of Varian Trilogy accelerator, combined with measurements of superficial dose distribution by an extrapolation method of multilayer radiochromic films, to estimate the dose calculation accuracy of four algorithms in the superficial region which was recommended in detail by the ICRU (International Commission on Radiation Units and Measurement) and the ICRP (International Commission on Radiological Protection). In superficial region, good agreement was achieved between MC simulation and film extrapolation method, with the mean differences less than 1%, 2% and 5% for 0°, 30° and 60°, respectively. The relative skin dose errors were 0.84%, 1.88% and 3.90%; the mean dose discrepancies (0°, 30° and 60°) between each of four algorithms and MC simulation were (2.41±1.55%, 3.11±2.40%, and 1.53±1.05%), (3.09±3.00%, 3.10±3.01%, and 3.77±3.59%), (3.16±1.50%, 8.70±2.84%, and 18.20±4.10%) and (14.45±4.66%, 10.74±4.54%, and 3.34±3.26%) for AXB, CCC, AAA and PBC respectively. Monte Carlo simulation verified the feasibility of the superficial dose measurements by multilayer Gafchromic films. And the rank

  11. Analysis of patient CT dose data using virtualdose

    Science.gov (United States)

    Bennett, Richard

    X-ray computer tomography has many benefits to medical and research applications. Recently, over the last decade CT has had a large increase in usage in hospitals and medical diagnosis. In pediatric care, from 2000 to 2006, abdominal CT scans increased by 49 % and chest CT by 425 % in the emergency room (Broder 2007). Enormous amounts of effort have been performed across multiple academic and government groups to determine an accurate measure of organ dose to patients who undergo a CT scan due to the inherent risks with ionizing radiation. Considering these intrinsic risks, CT dose estimating software becomes a necessary tool that health care providers and radiologist must use to determine many metrics to base the risks versus rewards of having an x-ray CT scan. This thesis models the resultant organ dose as body mass increases for patients with all other related scan parameters fixed. In addition to this,this thesis compares a modern dose estimating software, VirtualDose CT to two other programs, CT-Expo and ImPACT CT. The comparison shows how the software's theoretical basis and the phantom they use to represent the human body affect the range of results in organ dose. CT-Expo and ImPACT CT dose estimating software uses a different model for anatomical representation of the organs in the human body and the results show how that approach dramatically changes the outcome. The results categorizes four datasets as compared to the three software types where the appropriate phantom was available. Modeling was done to simulate chest abdominal pelvis scans and whole body scans. Organ dose difference versus body mass index shows as body mass index (BMI) ranges from 23.5 kg/m 2 to 45 kg/m2 the amount of organ dose also trends a percent change from -4.58 to -176.19 %. Comparing organ dose difference with increasing x-ray tube potential from 120 kVp to 140 kVp the percent change in organ dose increases from 55 % to 65 % across all phantoms. In comparing VirtualDose to CT

  12. Biological dose estimation for accidental supra-high dose gamma-ray exposure

    International Nuclear Information System (INIS)

    Chen, Y.; Yan, X.K.; Du, J.; Wang, Z.D.; Zhang, X.Q.; Zeng, F.G.; Zhou, P.K.

    2011-01-01

    To correctly estimate the biological dose of victims accidentally exposed to a very high dose of 60 Co gamma-ray, a new dose-effect curve of chromosomal dicentrics/multicentrics and rings in the supra-high dose range was established. Peripheral blood from two healthy men was irradiated in vitro with doses of 60 Co gamma-rays ranging from 6 to 22 Gy at a dose rate of 2.0 Gy/min. Lymphocytes were concentrated, cultured and harvested at 52 h, 68 h and 72 h. The numbers of dic + r were counted. The dose-effect curves were established and validated using comparisons with doses from the Tokai-mura accident and were then applied to two victims of supra-high dose exposure accident. The results indicated that there were no significant differences in chromosome aberration frequency among the different culture times from 52 h to 72 h. The 6-22 Gy dose-effect curve was fitted to a linear quadratic model Y = -2.269 + 0.776D - 7.868 x l0 -3 D 2 . Using this mathematic model, the dose estimates were similar to data from Tokai-mura which were estimated by PCC ring. Whole body average doses of 9.7 Gy and 18.1 Gy for two victims in the Jining accident were satisfactorily given. We established and successfully applied a new dose-effect curve of chromosomal dicentrics plus ring (dic + r) after 6-22 Gy γ-irradiation from a supra-high dose 60 Co gamma-ray accident.

  13. The relative importance of ingestion for multiple pathway dose assessments

    International Nuclear Information System (INIS)

    Wicker, W.; Grogan, H.; Bergstroem, U.; Hoffman, O.

    1991-01-01

    The general purpose of this report is to examine the relative importance of ingestion pathways, and particularly food chain transport in overall dose assessment. The importance of ingestion pathways is examined for various release scenarios and radionuclides because the findings are expected to differ with circumstances. The degree to which contaminated food products contribute to the total dose will affect the importance of accuracy and uncertainty of food chain model predictions, which is the main thrust of the Biospheric Model Validation Study (BIOMOVS). This analysis requires that all modes of radiation exposure be examined, including inhalation, external exposure, and the various ingestion pathways. (2 figs., 2 tabs.)

  14. A novel approach for estimating ingested dose associated with paracetamol overdose.

    Science.gov (United States)

    Zurlinden, Todd J; Heard, Kennon; Reisfeld, Brad

    2016-04-01

    In cases of paracetamol (acetaminophen, APAP) overdose, an accurate estimate of tissue-specific paracetamol pharmacokinetics (PK) and ingested dose can offer health care providers important information for the individualized treatment and follow-up of affected patients. Here a novel methodology is presented to make such estimates using a standard serum paracetamol measurement and a computational framework. The core component of the computational framework was a physiologically-based pharmacokinetic (PBPK) model developed and evaluated using an extensive set of human PK data. Bayesian inference was used for parameter and dose estimation, allowing the incorporation of inter-study variability, and facilitating the calculation of uncertainty in model outputs. Simulations of paracetamol time course concentrations in the blood were in close agreement with experimental data under a wide range of dosing conditions. Also, predictions of administered dose showed good agreement with a large collection of clinical and emergency setting PK data over a broad dose range. In addition to dose estimation, the platform was applied for the determination of optimal blood sampling times for dose reconstruction and quantitation of the potential role of paracetamol conjugate measurement on dose estimation. Current therapies for paracetamol overdose rely on a generic methodology involving the use of a clinical nomogram. By using the computational framework developed in this study, serum sample data, and the individual patient's anthropometric and physiological information, personalized serum and liver pharmacokinetic profiles and dose estimate could be generated to help inform an individualized overdose treatment and follow-up plan. © 2015 The British Pharmacological Society.

  15. Fast in vivo volume dose reconstruction via reference dose perturbation

    International Nuclear Information System (INIS)

    Lu, Weiguo; Chen, Mingli; Mo, Xiaohu; Parnell, Donald; Olivera, Gustavo; Galmarini, Daniel

    2014-01-01

    Purpose: Accurate on-line reconstruction of in-vivo volume dose that accounts for both machine and patient discrepancy is not clinically available. We present a simple reference-dose-perturbation algorithm that reconstructs in-vivo volume dose fast and accurately. Methods: We modelled the volume dose as a function of the fluence map and density image. Machine (output variation, jaw/leaf position errors, etc.) and patient (setup error, weight loss, etc.) discrepancies between the plan and delivery were modelled as perturbation of the fluence map and density image, respectively. Delivered dose is modelled as perturbation of the reference dose due to change of the fluence map and density image. We used both simulated and clinical data to validate the algorithm. The planned dose was used as the reference. The reconstruction was perturbed from the reference and accounted for output-variations and the registered daily image. The reconstruction was compared with the ground truth via isodose lines and the Gamma Index. Results: For various plans and geometries, the volume doses were reconstructed in few seconds. The reconstruction generally matched well with the ground truth. For the 3%/3mm criteria, the Gamma pass rates were 98% for simulations and 95% for clinical data. The differences mainly appeared on the surface of the phantom/patient. Conclusions: A novel reference-dose-perturbation dose reconstruction model is presented. The model accounts for machine and patient discrepancy from planning. The algorithm is simple, fast, yet accurate, which makes online in-vivo 3D dose reconstruction clinically feasible.

  16. Evaluation of dose according to the volume and respiratory range during SBRT in lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Deuk Hee [Dept. of Radiation Oncology, Busan Paik Hospital, Inje University, Busan (Korea, Republic of); Park, Eun Tae; Kim, Jung Hoon; Kang, Se Seik [Dept. of Radiological Science, College of Health Sciences, Catholic University of Pusan, Busan (Korea, Republic of)

    2016-09-15

    Stereotactic body radiotherapy is effective technic in radiotherapy for low stage lung cancer. But lung cancer is affected by respiratory so accurately concentrate high dose to the target is very difficult. In this study, evaluated the target volume according to how to take the image. And evaluated the dose by photoluminescence glass dosimeter according to how to contour the volume and respiratory range. As a result, evaluated the 4D CT volume was 10.4 cm{sup 3} which was closest value of real size target. And in dose case is internal target volume dose was 10.82, 16.88, 21.90 Gy when prescribed dose was 10, 15, 20 Gy and it was the highest dose. Respiratory gated radiotherapy dose was more higher than internal target volume. But it made little difference by respiratory range. Therefore, when moving cancer treatment, acquiring image by 4D CT, contouring internal target volume and respiratory gated radiotherapy technic would be the best way.

  17. Evaluation of dose according to the volume and respiratory range during SBRT in lung cancer

    International Nuclear Information System (INIS)

    Lee, Deuk Hee; Park, Eun Tae; Kim, Jung Hoon; Kang, Se Seik

    2016-01-01

    Stereotactic body radiotherapy is effective technic in radiotherapy for low stage lung cancer. But lung cancer is affected by respiratory so accurately concentrate high dose to the target is very difficult. In this study, evaluated the target volume according to how to take the image. And evaluated the dose by photoluminescence glass dosimeter according to how to contour the volume and respiratory range. As a result, evaluated the 4D CT volume was 10.4 cm 3 which was closest value of real size target. And in dose case is internal target volume dose was 10.82, 16.88, 21.90 Gy when prescribed dose was 10, 15, 20 Gy and it was the highest dose. Respiratory gated radiotherapy dose was more higher than internal target volume. But it made little difference by respiratory range. Therefore, when moving cancer treatment, acquiring image by 4D CT, contouring internal target volume and respiratory gated radiotherapy technic would be the best way

  18. RADIATION HYGIENIC MONITORING AND ASSESSMENT OF POPULATION DOSES IN RADIOACTIVELY CONTAMINATED AREAS OF TULA REGION

    Directory of Open Access Journals (Sweden)

    T. M. Chichura

    2016-01-01

    Full Text Available The goal. The analyses of radiation hygienic monitoring conducted in Tula region territories affected by the Chernobyl NPP accident regarding cesium-137 and strontium- 90 in the local foodstuffs and the analyses of populational annual effective dose. The materials and methods. The survey was conducted in Tula Region since 1997 to 2015. Over that period, more than fifty thousand samples of the main foodstuffs from the post-Chernobyl contaminated area were analyzed. Simultaneously with that, the external gamma - radiation dose rate was measured in the fixed control points. The dynamics of cesium -137 and strontium-90 content in foodstuffs were assessed along with the maximum values of the mean annual effective doses to the population and the contribution of the collective dose from medical exposures into the structure of the annual effective collective dose to the population. The results. The amount of cesium-137 and strontium -90 in the local foodstuffs was identified. The external gamma- radiation dose rate values were found to be stable and not exceeding the natural fluctuations range typical for the middle latitudes of Russia’s European territory. The maximum mean annual effective dose to the population reflects the stable radiation situation and does not exceed the permissible value of 1 mSv. The contribution of the collective dose from medical exposures of the population has been continuously reducing as well as the average individual dose to the population per one medical treatment under the annual increase of the medical treatments quantities. The conclusion. There is no exceedance of the admissible levels of cesium-137 and strontium- 90 content in the local foodstuffs. The mean annual effective dose to the population has decreased which makes it possible to transfer the settlements affected by the Chernobyl NPP accident to normal life style. This is covered by the draft concept of the settlements’ transfer to normal life style.

  19. Estimation of the transit dose component in high dose rate brachytherapy

    International Nuclear Information System (INIS)

    Garcia Romero, A.; Millan Cebrian, E.; Lozano Flores, F.J.; Lope Lope, R.; Canellas Anoz, M.

    2001-01-01

    Current high dose rate brachytherapy (HDR) treatment planning systems usually calculate dose only from source stopping positions (stationary component), but fails to account for the administered dose when the source is moving (dynamic component or transit dose). Numerical values of this transit dose depends upon the source velocity, implant geometry, source activity and prescribed dose. In some HDR treatments using particular geometry the transit dose cannot be ignored because it increases the dose at the prescriptions points and also could increase potential late tissue complications as predicted by the linear quadratic model. International protocols recommend to verify this parameter. The aim of this paper has been to establish a procedure for the transit dose calculation for the Gammamed 12i equipment at the RT Department in the Clinical University Hospital (Zaragoza-Spain). A numeric algorithm was implemented based on a dynamic point approximation for the moving HDR source and the calculated results for the entrance-exit transit dose was compared with TLD measurements made in some discrete points. (author) [es

  20. Sodium benzoate, a food preservative, affects the functional and activation status of splenocytes at non cytotoxic dose.

    Science.gov (United States)

    Yadav, Ashish; Kumar, Arvind; Das, Mukul; Tripathi, Anurag

    2016-02-01

    Sodium benzoate (SB) is a widely used food preservative due to its bacteriostatic and fungistatic properties. The acceptable daily intake of SB is 5 mg/kg-bw, however, it has been found to be used in the food commodities at relatively high levels (2119 mg/kg). Earlier studies on SB have shown its immunosuppressive properties, but comprehensive immunotoxicity data is lacking. Our studies have shown that SB was non cytotoxic in splenocytes up to 1000 μg/ml for 72 h, however at 2500 μg/ml it was found to be cytotoxic. Thus, 1000 μg/ml dose of SB was chosen for the subsequent experiments. SB significantly suppresses the proliferation of Con A and LPS stimulated splenocytes at 72 h, while allogenic response of T cells was significantly decreased after 96 h. SB did not affect the relative expression of CD3e or CD4 molecules following 72 h exposure, however, it downregulated the relative expression of CD8 co-receptor. Further, exposure of splenocytes to SB for 72 h led to reduced expression of CD28 and CD95, which play a vital role in T cell activation. SB also suppresses the relative expression of CD19, CD40 and CD95 receptors on B cells after 72 h. In addition to the functional responses, SB lowered the expression of IL4, IL6, IFNγ and IL17 cytokines in Con A stimulated splenocytes; and IL6, IFNγ and TNFα in LPS stimulated splenocytes following 48 h of exposure. Taken together, the present study is suggestive of the immunomodulatory potential of SB. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Does selenium supplementation affect thyroid function?

    DEFF Research Database (Denmark)

    Winther, Kristian Hillert; Bonnema, Steen Joop; Cold, Frederik

    2015-01-01

    OBJECTIVE: Selenium is present in the active site of proteins important for thyroid hormone synthesis and metabolism. The objective of this study is to investigate the effect of selenium supplementation in different doses on thyroid function, under conditions of suboptimal dietary selenium intake....... DESIGN: The Danish PREvention of Cancer by Intervention with SElenium pilot study (DK-PRECISE) is a randomized, double-blinded, placebo-controlled trial. A total of 491 males and females aged 60-74 years were randomized to 100 μg (n=124), 200 μg (n=122), or 300 μg (n=119) selenium-enriched yeast......=0.015), respectively, per 100 μg/day increase, with insignificant differences between 6 months and 5 years. No significant effects were found for FT3 and FT3:FT4 ratio. CONCLUSIONS: In euthyroid subjects, selenium supplementation minutely and dose-dependently affects thyroid function, when compared...

  2. Effective dose and dose to crystalline lens during angiographic procedures

    International Nuclear Information System (INIS)

    Pages, J.

    1998-01-01

    The highest radiation doses levels received by radiologists are observed during interventional procedures. Doses to forehead and neck received by a radiologist executing angiographic examinations at the department of radiology at the academic hospital (AZ-VUB) have been measured for a group of 34 examinations. The doses to crystalline lens and the effective doses for a period of one year have been estimated. For the crystalline lens the maximum dose approaches the ICRP limit, that indicates the necessity for the radiologist to use leaded glasses. (N.C.)

  3. Dose rate estimation of the Tohoku hynobiid salamander, Hynobius lichenatus, in Fukushima.

    Science.gov (United States)

    Fuma, Shoichi; Ihara, Sadao; Kawaguchi, Isao; Ishikawa, Takahiro; Watanabe, Yoshito; Kubota, Yoshihisa; Sato, Youji; Takahashi, Hiroyuki; Aono, Tatsuo; Ishii, Nobuyoshi; Soeda, Haruhi; Matsui, Kumi; Une, Yumi; Minamiya, Yukio; Yoshida, Satoshi

    2015-05-01

    The radiological risks to the Tohoku hynobiid salamanders (class Amphibia), Hynobius lichenatus due to the Fukushima Dai-ichi Nuclear Power Plant accident were assessed in Fukushima Prefecture, including evacuation areas. Aquatic egg clutches (n = 1 for each sampling date and site; n = 4 in total), overwintering larvae (n = 1-5 for each sampling date and site; n = 17 in total), and terrestrial juveniles or adults (n = 1 or 3 for each sampling date and site; n = 12 in total) of H. lichenatus were collected from the end of April 2011 to April 2013. Environmental media such as litter (n = 1-5 for each sampling date and site; n = 30 in total), soil (n = 1-8 for each sampling date and site; n = 31 in total), water (n = 1 for each sampling date and site; n = 17 in total), and sediment (n = 1 for each sampling date and site; n = 17 in total) were also collected. Activity concentrations of (134)Cs + (137)Cs were 1.9-2800, 0.13-320, and 0.51-220 kBq (dry kg) (-1) in the litter, soil, and sediment samples, respectively, and were 0.31-220 and <0.29-40 kBq (wet kg)(-1) in the adult and larval salamanders, respectively. External and internal absorbed dose rates to H. lichenatus were calculated from these activity concentration data, using the ERICA Assessment Tool methodology. External dose rates were also measured in situ with glass dosimeters. There was agreement within a factor of 2 between the calculated and measured external dose rates. In the most severely contaminated habitat of this salamander, a northern part of Abukuma Mountains, the highest total dose rates were estimated to be 50 and 15 μGy h(-1) for the adults and overwintering larvae, respectively. Growth and survival of H. lichenatus was not affected at a dose rate of up to 490 μGy h(-1) in the previous laboratory chronic gamma-irradiation experiment, and thus growth and survival of this salamander would not be affected, even in the most severely contaminated habitat in Fukushima Prefecture. However, further

  4. Genetic factors affecting radiosensitivity and cancer predisposition: application of a continuous low dose-rate irradiation colony formation assay to select radiosensitive retinoblastoma family members for correction with a cDNA library

    International Nuclear Information System (INIS)

    Wilson, P.F.; Nagasawa, H.; Bedford, J.S.; Little, J.B.

    2003-01-01

    Full text: The aim of this study is to identify new or undescribed functions of radiosensitivity and genomic instability genes using a continuous low dose-rate colony formation assay. This assay expands on the standard colony formation assay, whereby colony formation ability (retention of proliferative capacity) is measured during continuous low dose-rate irradiation rather than 10-14 days following the completion of such exposures. This approach has previously employed by the Bedford laboratory to identify a Prkdc (DNA-PKcs) mutant of CHO cells, irs-20. In this study we examine the growth response of fibroblasts derived from recently identified radiosensitive retinoblastoma family members, both affected probands and their unaffected parents, and various apparently normal fibroblast lines obtained from the NIGMS Human Genetic Cell Repository (Coriell Medical Institute, Camden, NJ). Colony formation was assayed by plating single cells, exposing them at 37 deg C to continuous Cs-137 gamma irradiation at dose rates of 0.5-8.5 cGy/h, and scoring survivors as colonies with >100 viable cells. The retinoblastoma family members display severely limited growth (survival less than 10E-3) at dose rates greater than 2-2.5 cGy/h, while the apparently normal cell lines do not display such inhibited growth until 6-7 cGy/h. Two of the retinoblastoma family cell lines, MF-6F and MF-15F (both unaffected but radiosensitive parents), were selected as targets of transfection with a viral cDNA library (ViraPort human cDNA library, Stratagene Cloning Systems, La Jolla, CA) and subjected to a ∼3 cGy/h selection dose rate, where uncorrected survival relative to normal cells is lower by a factor of 50-150. Colonies recovered will provide valuable information regarding the genetic nature of their radiosensitivity (possibly involving chromosome stability, DNA repair, and/or cell cycle regulatory pathways), that may influence risks for cancer and heritable effects for a previously

  5. Measurement of absorbed dose with a bone-equivalent extrapolation chamber

    International Nuclear Information System (INIS)

    DeBlois, Francois; Abdel-Rahman, Wamied; Seuntjens, Jan P.; Podgorsak, Ervin B.

    2002-01-01

    A hybrid phantom-embedded extrapolation chamber (PEEC) made of Solid Water trade mark sign and bone-equivalent material was used for determining absorbed dose in a bone-equivalent phantom irradiated with clinical radiation beams (cobalt-60 gamma rays; 6 and 18 MV x rays; and 9 and 15 MeV electrons). The dose was determined with the Spencer-Attix cavity theory, using ionization gradient measurements and an indirect determination of the chamber air-mass through measurements of chamber capacitance. The collected charge was corrected for ionic recombination and diffusion in the chamber air volume following the standard two-voltage technique. Due to the hybrid chamber design, correction factors accounting for scatter deficit and electrode composition were determined and applied in the dose equation to obtain absorbed dose in bone for the equivalent homogeneous bone phantom. Correction factors for graphite electrodes were calculated with Monte Carlo techniques and the calculated results were verified through relative air cavity dose measurements for three different polarizing electrode materials: graphite, steel, and brass in conjunction with a graphite collecting electrode. Scatter deficit, due mainly to loss of lateral scatter in the hybrid chamber, reduces the dose to the air cavity in the hybrid PEEC in comparison with full bone PEEC by 0.7% to ∼2% depending on beam quality and energy. In megavoltage photon and electron beams, graphite electrodes do not affect the dose measurement in the Solid Water trade mark sign PEEC but decrease the cavity dose by up to 5% in the bone-equivalent PEEC even for very thin graphite electrodes (<0.0025 cm). In conjunction with appropriate correction factors determined with Monte Carlo techniques, the uncalibrated hybrid PEEC can be used for measuring absorbed dose in bone material to within 2% for high-energy photon and electron beams

  6. Humidity affects the morphology of particles emitted from beclomethasone dipropionate pressurized metered dose inhalers.

    Science.gov (United States)

    Ivey, James W; Bhambri, Pallavi; Church, Tanya K; Lewis, David A; McDermott, Mark T; Elbayomy, Shereen; Finlay, Warren H; Vehring, Reinhard

    2017-03-30

    The effects of propellant type, cosolvent content, and air humidity on the morphology and solid phase of the particles produced from solution pressurized metered dose inhalers containing the corticosteroid beclomethasone dipropionate were investigated. The active ingredient was dissolved in the HFA propellants 134a and 227ea with varying levels of the cosolvent ethanol and filled into pressurized metered dose inhalers. Inhalers were actuated into an evaporation chamber under controlled temperature and humidity conditions and sampled using a single nozzle, single stage inertial impactor. Particle morphology was assessed qualitatively using field emission scanning electron microscopy and focused ion beam-helium ion microscopy. Drug solid phase was assessed using Raman microscopy. The relative humidity of the air during inhaler actuation was found to have a strong effect on the particle morphology, with solid spheroidal particles produced in dry air and highly porous particles produced at higher humidity levels. Air humidification was found to have no effect on the solid phase of the drug particles, which was predominantly amorphous for all tested formulations. A critical level of air relative humidity was required to generate porous particles for each tested formulation. This critical relative humidity was found to depend on the amount of ethanol used in the inhaler, but not on the type of propellant utilized. The results indicate that under the right circumstances water vapor saturation followed by nucleated water condensation or ice deposition occurs during particle formation from evaporating propellant-cosolvent-BDP droplets. This finding reveals the importance of condensed water or ice as a templating agent for porosity when particle formation occurs at saturated conditions, with possible implications on the pharmacokinetics of solution pMDIs and potential applications in particle engineering for drug delivery. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Liposome accumulation in irradiated tumors display important tumor and dose dependent differences

    DEFF Research Database (Denmark)

    Hansen, Anders Elias; Fliedner, Frederikke Petrine; Henriksen, Jonas Rosager

    2018-01-01

    Radiation therapy may affect several important parameters in the tumor microenvironment and thereby influence the accumulation of liposomes by the enhanced permeability and retention (EPR)-effect. Here we investigate the effect of single dose radiation therapy on liposome tumor accumulation by PET...

  8. Experimental research on fresh mussel meat irradiated by high-dose electron beam

    International Nuclear Information System (INIS)

    Xiao Lin; Lu Ruifeng; Hu Huachao; Wang Chaoqi; Liu Yanna

    2011-01-01

    The sterilization storage of fresh mussel irradiated high-dose electron beam was studied. From the subjective assessment by the weighted average of the test and other determined parameters, it can be concluded that the flavor of fresh mussel meat sealed canned food irradiated by high-dose electron beam has not been significant affected, and various micro-organisms can be killed effectively, which means that the irradiated fresh mussel meat can be preserved for long-term at room temperature. Therefore the method might resolve the problems induced by traditional frozen preservation methods. (authors)

  9. Prescribing and evaluating target dose in dose-painting treatment plans

    DEFF Research Database (Denmark)

    Håkansson, Katrin; Specht, Lena; Aznar, Marianne C

    2014-01-01

    BACKGROUND: Assessment of target dose conformity in multi-dose-level treatment plans is challenging due to inevitable over/underdosage at the border zone between dose levels. Here, we evaluate different target dose prescription planning aims and approaches to evaluate the relative merit of such p......-painting and multi-dose-level plans. The tool can be useful for quality assurance of multi-center trials, and for visualizing the development of treatment planning in routine clinical practice....... of such plans. A quality volume histogram (QVH) tool for history-based evaluation is proposed. MATERIAL AND METHODS: Twenty head and neck cancer dose-painting plans with five prescription levels were evaluated, as well as clinically delivered simultaneous integrated boost (SIB) plans from 2010 and 2012. The QVH...

  10. Radiation doses to patients from x-ray examinations - development from 2005 to 2008

    International Nuclear Information System (INIS)

    Leitz, Wolfram; Almen, Anja

    2010-04-01

    Data has been compiled and analyzed and compared with the earlier reports. Radiation doses were tested for possible links with various parameters (eg type of x-ray equipment, image recording systems, different technique factors). In conventional x-ray examinations radiation doses were, for equipment with direct digital image receivers, in average 30% lower than for those with photo plates. Mammography doses were, with one exception, the same for all types of equipment and video receivers. The CT-examinations had a small trend for higher doses for new equipment as compared to earlier. Use of exposure automation did not affect radiation doses. Compared with 2006, the doses of conventional surveys decreased by an average of 21%. One third of this dose reduction can be attributed the introduction of direct digital system whose use grew by about 30%. Most of the dose reduction can be attributed to the actions carried out to lower the dose of the reference level. Doses for the CT scan showed only a weak downwards trend. Mammography Doses decreased by an average of just over 10% a large part dependent on increased number of Sectra equipment. The system of diagnostic reference levels have again shown to have positive influence on the radiation level at the x-ray examinations, this is most pronounced for conventional radiography. There is still a large potential for dose reduction, and a measure to achieve this is to reduce the current reference levels. Very few diagnostic Standard doses are higher than the reference level. A reduction of the reference levels corresponding to the third quartile of dose distribution could lead further dose decrease of 10-20%. The corresponding reduction in dose should be done also for the DT and mammograms when lowering the reference level, there are few standard doses higher than the current reference levels

  11. Spontaneous mutation rates and the rate-doubling dose

    International Nuclear Information System (INIS)

    Von Borstel, R.C.; Moustaccki, E.; Latarjet, R.

    1978-01-01

    The amount of radiation required to double the frequency of mutations or tumours over the rate of those that occur spontaneously is called the rate-doubling dose. An equivalent concept has been proposed for exposure to other environmental mutagens. The doubling dose concept is predicated on the assumption that all human populations have the same spontaneous mutation rate, and that this spontaneous mutation rate is known. It is now established for prokaryotes and lower eukaryotes that numerous genes control the spontaneous mutation rate, and it is likely that the same is true for human cells as well. Given that the accepted mode of evolution of human populatons is from small, isolated groups of individuals, it seems likely that each population would have a different spontaneous mutation rate. Given that a minimum of twenty genes control or affect the spontaneous mutation rate, and that each of these in turn is susceptible to spontaneously arising or environmentally induced mutations, it seems likely that every individual within a population (except for siblings from identical multiple births) will have a unique spontaneous mutation rate. If each individual in a population does have a different spontaneous mutation rate, the doubling dose concept, in rigorous terms, is fallacious. Therefore, as with other concepts of risk evaluation, the doubling dose concept is subject to criticism. Nevertheless, until we know individual spontaneous mutation rates with precision, and can evaluate risks based on this information, the doubling dose concept has a heuristic value and is needed for practical assessment of risks for defined populations. (author)

  12. Predicted effects of countermeasures on radiation doses from contaminated food

    International Nuclear Information System (INIS)

    Yamamoto, Hideaki; Nielsen, S.P.; Nielsen, F.

    1993-02-01

    Quantitative assessments of the effects on radiation-dose reductions from nine typical countermeasures against accidental fod contamination have been carried out with dynamic radioecological models. The foodstuffs are assumed to be contaminated with iodine-131, caesium-134 and caesium-137 after a release of radioactive materials from the Ringhals nuclear power station in Sweden resulting from a hypothetical core melt accident. The release of activity of these radionuclides is assumed at 0.07% of the core inventory of the unit 1 reactor (1600 TBq of I-131, 220 TBq of Cs-134 and 190 TBq of Cs-137). Radiation doses are estimated for the 55,000 affected inhabitants along the south-eastern coast of Sweden eating locally produced foodstuffs. The average effective dose equivalent to an individual in the critical group is predicted to be 2.9 mSv from food consumption contaminated with I-131. An accident occurring during winter is estimated to cause average individual doses of 0.32 mSv from Cs-134 and 0.47 mSv from Cs-137, and 9.4 mSv and 6.8 mSv from Cs-134 and Cs-137, respectively, for an accident occurring during summer. Doses from the intake of radioiodine may be reduced by up to a factor of 60 by rejecting contaminated food for 30 days. For the doses from radiocaesium, the largest effect is found form deep ploughing which may reduce the dose by up to a factor of 80. (au) (12 tabs., 6 ills., 19 refs.)

  13. Characteristics of dental pulp in human upper first premolar teeth based on immunohistochemical and morphometric examinations.

    Science.gov (United States)

    Tomaszewska, Joanna Maria; Miskowiak, Bogdan; Matthews-Brzozowska, Teresa; Wierzbicki, Piotr

    2013-01-01

    Teeth extracted for orthodontic reasons are commonly considered as healthy. Therefore, it is possible to examine structure of the dental pulp can be fully recognized and how it is affected by malocclusion. The aim of the study was to evaluate by immunohistochemistry (IHC) and morphometry dental pulp in human upper first premolar teeth extracted for orthodontic reasons. The material comprised 36 teeth of 20 patients in the age range 16-26 years. By the use of IHC markers the presence of immunocompetent cells (CD20, CD45RO, and CD68), blood vessels (CD31) and nerves (PGP9.5) were examined in the pulp. Inflammatory infiltrates and tissue atrophy were observed in 24 and 10 teeth, respectively. Strong positive correlation between the width of the odontoblastic layer, the number of rows of odontoblast nuclei and the increase of MVA (microvessel area) in the pulp of atrophic teeth was found. The cellular infiltrations found in H&E-stained sections were identified by IHC as memory T cells (CD45RO+) and B lymphocytes (CD20+) with macrophages (CD68+) present at the periphery. The CD20 antigen was intensively expressed in 13 teeth, CD45RO in 33 teeth, and CD68 in 20 teeth. Thus, despite the lack of any clinical signs of pulp disease many teeth extracted for orthodontic reasons show focal pulp inflammation and atrophy which probably results from the malocclusion stress accompanying teeth crowding.

  14. Distribution of syndecan-1 protein in developing mouse teeth

    Directory of Open Access Journals (Sweden)

    Anna eFilatova

    2015-01-01

    Full Text Available Syndecan-1 is a cell surface proteoglycan involved in the regulation of various biological processes such as proliferation, migration, condensation and differentiation of cells, intercellular communication and morphogenesis. The extracellular domain of syndecan-1 can bind to extracellular matrix components and signalling molecules, while its intracellular domain interacts with cytoskeletal proteins, thus allowing the transfer of information about extracellular environment changes into the cell that consequently affect cellular behaviour. Although previous studies have shown syndecan-1 expression during precise stages of tooth development, there is no equivalent study regrouping the expression patterns of syndecan-1 during all stages of odontogenesis. Here we examined the distribution of syndecan-1 protein in embryonic and postnatal developing mouse molars and incisors. Syndecan-1 distribution in mesenchymal tissues such as dental papilla and dental follicle was correlated with proliferating events and its expression was often linked to stem cell niche territories. Syndecan-1 was also expressed in mesenchymal cells that will differentiate into the dentin producing odontoblasts, but not in differentiated functional odontoblasts. In the epithelium, syndecan-1 was detected in all cell layers, by the exception of differentiated ameloblasts that form the enamel. Furthermore, syndecan-1 was expressed in osteoblast precursors and osteoclasts of the alveolar bone that surrounds the developing tooth germs. Taken together these results show the dynamic nature of syndecan-1 expression during odontogenesis and suggest its implication in various processes of tooth development and homeostasis.

  15. Isobio software: biological dose distribution and biological dose volume histogram from physical dose conversion using linear-quadratic-linear model.

    Science.gov (United States)

    Jaikuna, Tanwiwat; Khadsiri, Phatchareewan; Chawapun, Nisa; Saekho, Suwit; Tharavichitkul, Ekkasit

    2017-02-01

    To develop an in-house software program that is able to calculate and generate the biological dose distribution and biological dose volume histogram by physical dose conversion using the linear-quadratic-linear (LQL) model. The Isobio software was developed using MATLAB version 2014b to calculate and generate the biological dose distribution and biological dose volume histograms. The physical dose from each voxel in treatment planning was extracted through Computational Environment for Radiotherapy Research (CERR), and the accuracy was verified by the differentiation between the dose volume histogram from CERR and the treatment planning system. An equivalent dose in 2 Gy fraction (EQD 2 ) was calculated using biological effective dose (BED) based on the LQL model. The software calculation and the manual calculation were compared for EQD 2 verification with pair t -test statistical analysis using IBM SPSS Statistics version 22 (64-bit). Two and three-dimensional biological dose distribution and biological dose volume histogram were displayed correctly by the Isobio software. Different physical doses were found between CERR and treatment planning system (TPS) in Oncentra, with 3.33% in high-risk clinical target volume (HR-CTV) determined by D 90% , 0.56% in the bladder, 1.74% in the rectum when determined by D 2cc , and less than 1% in Pinnacle. The difference in the EQD 2 between the software calculation and the manual calculation was not significantly different with 0.00% at p -values 0.820, 0.095, and 0.593 for external beam radiation therapy (EBRT) and 0.240, 0.320, and 0.849 for brachytherapy (BT) in HR-CTV, bladder, and rectum, respectively. The Isobio software is a feasible tool to generate the biological dose distribution and biological dose volume histogram for treatment plan evaluation in both EBRT and BT.

  16. Time-dose considerations in the treatment of anal cancer

    International Nuclear Information System (INIS)

    Constantinou, Eugene C.; Daly, William; Fung, Claire Y.; Willett, Christopher G.; Kaufman, Donald S.; DeLaney, Thomas F.

    1997-01-01

    Purpose: To analyze the impact of patient and treatment parameters in concurrent chemoradiation treatment for anal carcinoma. Methods and Materials: Retrospective review of 50 MO anal cancer patients treated from 1984-1994. Most patients received concurrent 5-FU, mitomycin, and radiation. Local control and disease-free/overall survival were determined and analyzed according to patient and treatment parameters. Results: With 43 month median follow-up, projected overall survival is 66% at 5 and 8 years. Disease-free survival is 67% at 5 years and 59% at 8 years. Local control is 70% at 5 and 8 years. Doses of ≥54 Gy are associated with improved 5-year survival (84 vs. 47%, p = 0.02), disease-free survival (74 v. 56%, p = 0.09), and local control (77 vs. 61%, p = 0.04). Although local control, disease-free survival, and overall survival were improved in patients whose overall treatment time was <40 days, this was not statistically significant. Outcome in the four patients with pretreatment hemoglobin (Hgb) <10 appeared worse with 3-year overall survival 50 vs. 68% (p = 0.07), disease-free survival 0 vs. 67% (p = 0.11), and local control 0 vs. 74% (p = 0.05). Projected 5-year overall survival, relapse-free survival, and local control in 4 HIV (+) patients is 0, 75, and 75%. Multivariate analysis reveals that dose (p 0.02) and Hgb (p = 0.05) independently affect local control, dose (p = 0.02) affects disease-free survival, and dose (p = 0.01), Hgb (p = 0.03), T-stage (p = 0.03), and HIV-status (0.07) independently influence overall survival. Conclusion: Radiation doses of ≥54 Gy are associated with significantly improved survival and local control in anal cancer patients treated with chemoradiation. Overall treatment times of less than 40 days are associated with a trend towards improved outcome, but this is not significant. Pretreatment hemoglobin <10 is associated with worse treatment outcome. Survival of HIV (+) patient is poor, but the majority of such patients

  17. Simulation of the field dose of the irradiator PX γ 30 using MCNP

    International Nuclear Information System (INIS)

    Torres, N.; Prieto, E. F.; Chavez, A.; Rosales, J.

    2011-01-01

    Given the acceptance and actual application of radiation technology for research purposes, industrial and trade is increasing, and that safety and quality of the product being treated by radiation technology is a function of absorbed dose, it becomes necessary to have a good characterization of the radiation field at processing volume, avoiding in this way that the product receives a different dose that affects its properties, or failure to reach the desired effect, which in many cases would be embarrassing. The simulation using the MCNP program, which uses probabilistic Monte Carlo code, can correctly characterize the dose field in the irradiation chamber of research irradiator PX γ 30 used in the CEADEN. (Author)

  18. Reduced-Nicotine Cigarettes in Young Smokers: Impact of Nicotine Metabolism on Nicotine Dose Effects.

    Science.gov (United States)

    Faulkner, Paul; Ghahremani, Dara G; Tyndale, Rachel F; Cox, Chelsea M; Kazanjian, Ari S; Paterson, Neil; Lotfipour, Shahrdad; Hellemann, Gerhard S; Petersen, Nicole; Vigil, Celia; London, Edythe D

    2017-07-01

    The use of cigarettes delivering different nicotine doses allows evaluation of the contribution of nicotine to the smoking experience. We compared responses of 46 young adult smokers to research cigarettes, delivering 0.027, 0.110, 0.231, or 0.763 mg nicotine, and conventional cigarettes. On five separate days, craving, withdrawal, affect, and sustained attention were measured after overnight abstinence and again after smoking. Participants also rated each cigarette, and the nicotine metabolite ratio (NMR) was used to identify participants as normal or slow metabolizers. All cigarettes equally alleviated craving, withdrawal, and negative affect in the whole sample, but normal metabolizers reported greater reductions of craving and withdrawal than slow metabolizers, with dose-dependent effects. Only conventional cigarettes and, to a lesser degree, 0.763-mg nicotine research cigarettes increased sustained attention. Finally, there were no differences between ratings of lower-dose cigarettes, but the 0.763-mg cigarettes and (even more so) conventional cigarettes were rated more favorably than lower-dose cigarettes. The findings indicate that smoking-induced relief of craving and withdrawal reflects primarily non-nicotine effects in slow metabolizers, but depends on nicotine dose in normal metabolizers. By contrast, relief of withdrawal-related attentional deficits and cigarette ratings depend on nicotine dose regardless of metabolizer status. These findings have bearing on the use of reduced-nicotine cigarettes to facilitate smoking cessation and on policy regarding regulation of nicotine content in cigarettes. They suggest that normal and slow nicotine metabolizers would respond differently to nicotine reduction in cigarettes, but that irrespective of metabolizer status, reductions to <0.763 mg/cigarette may contribute to temporary attentional deficits.

  19. Patient dose measurement and dose reduction in chest radiography

    Directory of Open Access Journals (Sweden)

    Milatović Aleksandra A.

    2014-01-01

    Full Text Available Investigations presented in this paper represent the first estimation of patient doses in chest radiography in Montenegro. In the initial stage of our study, we measured the entrance surface air kerma and kerma area product for chest radiography in five major health institutions in the country. A total of 214 patients were observed. We reported the mean value, minimum and third quartile values, as well as maximum values of surface air kerma and kerma area product of patient doses. In the second stage, the possibilities for dose reduction were investigated. Mean kerma area product values were 0.8 ± 0.5 Gycm2 for the posterior-anterior projection and 1.6 ± 0.9 Gycm2 for the lateral projection. The max/min ratio for the entrance surface air kerma was found to be 53 for the posterior-anterior projection and 88 for the lateral projection. Comparing the results obtained in Montenegro with results from other countries, we concluded that patient doses in our medical centres are significantly higher. Changes in exposure parameters and increased filtration contributed to a dose reduction of up to 36% for posterior-anterior chest examinations. The variability of the estimated dose values points to a significant space for dose reduction throughout the process of radiological practice optimisation.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-15

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

  1. Delivery of adjuvant sequential dose-dense FEC-Doc to patients with breast cancer is feasible, but dose reductions and toxicity are dependent on treatment sequence.

    Science.gov (United States)

    Wildiers, H; Dirix, L; Neven, P; Prové, A; Clement, P; Squifflet, P; Amant, F; Skacel, T; Paridaens, R

    2009-03-01

    This study prospectively investigates the impact of dose densification and altering sequence of fluorouracil, epirubicin and cyclophosphamide [FEC(100)] and docetaxel [Doc] on dose delivery and tolerability of adjuvant chemotherapy in breast cancer patients. 117 patients with high-risk primary operable breast cancer were randomized (1:1:2:2) to conventional (three cycles of 3-weekly FEC(100) then three cycles of 3-weekly Doc 100 mg/m(2) or reverse sequence) or dose-dense (dd) treatment (four 10- to 11-day cycles of FEC(75) then four 2-weekly cycles of Doc 75 mg/m(2), or the reverse). In the dd arms, pegfilgrastim was given on day 2 of each cycle, but only as secondary prophylaxis in conventional arms. The primary endpoint was the proportion of patients completing intended cycles at relative dose intensity >or=85% and this was achieved by 95% of patients in each group except for the ddDoc-->FEC group (90%). Dose intensity in the dd arms increased by 48% for FEC and 11% for docetaxel, compared with the conventional arms (both P Doc dose reductions were more frequent with dd treatment and when Doc was given after FEC. Grade 3-4 neutropenia was significantly more frequent with conventional treatment, while fatigue and hand-foot syndrome were numerically more common with dd treatment, particularly when Doc was given after FEC. Discussion Delivery of adjuvant sequential ddFEC and Doc is feasible with growth factor support, and chemotherapy sequence appeared to affect delivery of target doses and toxicity.

  2. Low-Dose versus Standard-Dose Intravenous Immunoglobulin to Prevent Fetal Intracranial Hemorrhage in Fetal and Neonatal Alloimmune Thrombocytopenia: A Randomized Trial.

    Science.gov (United States)

    Paridaans, Noortje P; Kamphuis, Marije M; Taune Wikman, Agneta; Tiblad, Eleonor; Van den Akker, Eline S; Lopriore, Enrico; Challis, Daniel; Westgren, Magnus; Oepkes, Dick

    2015-01-01

    Pregnancies at risk of fetal and neonatal alloimmune thrombocytopenia (FNAIT) are commonly treated using weekly intravenous immunoglobulin (IVIG) at 1 g/kg maternal weight. IVIG is an expensive multidonor human blood product with dose-related side effects. Our aim was to evaluate the effectiveness of IVIG at a lower dose, i.e., 0.5 g/kg. This was a randomized controlled multicenter trial conducted in Sweden, the Netherlands and Australia. Pregnant women with human platelet antigen alloantibodies and an affected previous child without intracranial hemorrhage (ICH) were enrolled. The participants were randomized to IVIG at 0.5 or 1 g/kg per week. The analyses were per intention to treat. The primary outcome was fetal or neonatal ICH. Secondary outcomes were platelet count at birth, maternal and neonatal IgG levels, neonatal treatment and bleeding other than ICH. A total of 23 women were randomized into two groups (low dose: n = 12; standard dose: n = 11). The trial was stopped early due to poor recruitment. No ICH occurred. The median newborn platelet count was 81 × 10(9)/l (range 8-269) in the 0.5 g/kg group versus 110 × 10(9)/l (range 11-279) in the 1 g/kg group (p = 0.644). The risk of adverse outcomes in FNAIT pregnancies treated with IVIG at 0.5 g/kg is very low, similar to that using 1 g/kg, although our uncompleted trial lacked the power to conclusively prove the noninferiority of using the low dose.

  3. Potential effects of climatic change on radiological doses from disposal of Canadian nuclear fuel waste

    International Nuclear Information System (INIS)

    Amiro, B.D.

    1997-01-01

    The environmental assessment of deep geologic disposal of Canadian nuclear fuel waste considers many processes that could affect radionuclide transport to humans over thousands of years. Climatic change is an important feature that will occur over these long times. Glaciation will likely occur within the next 100,000 years over much of Canada, and its impact on radiological doses has been assessed previously. In the present study, we investigate the potential effect of short- term climatic change, usually associated with global warming caused by increases in atmospheric trace gases. We study the main biosphere transport pathways causing a radiological dose to humans from 129 I, which is the most important radionuclide in disposal of Canadian used nuclear fuel. Irrigation of a garden with contaminated well water is the main pathway and it can be affected by changes in temperature and precipitation. A cold, wet climate decreases the need for irrigation, and this decreases the radiological dose. A drastic climatic change, such as an increase in temperature from 10 to 20 degrees C and decrease in precipitation from 0.3 to 0.2 m during the growing season, is estimated to increase the dose by a factor of four. This is a relatively small change compared to the range of doses that arise from the variability and uncertainty in many of the parameters used in the environmental assessment models. Therefore, it is likely that the results of probabilistic dose assessment models can include the consequences of short-term climatic change. 39 refs., 3 figs

  4. Hematological toxicity in radioimmunotherapy is predicted both by the computed absorbed whole body dose (cGy) and by the administered dose (mCi)

    International Nuclear Information System (INIS)

    Marquez, Sheri D.; Knox, Susan J.; Trisler, Kirk D.; Goris, Michael L.

    1997-01-01

    -90 anti-CD20 antibody treated group, in which the estimated whole body dose varied (D(cGy)), the decrease in these values was predicted by the linear (zero intercept) equations: DWBC = 0.01158 D(cGy) + 0.05247 D(mCi), DPLAT = 0.1476 D(cGy) + 3.043 D(mCi), and DN=0.0047 D(cGy)+0.0507D(mCi). In the Iodine-131 anti-CD20 antibody treated group, where D(cGy) was constant and equal to 75 cGy, the variation in toxicity was predicted by the linear equation DPLAT = -241 + 5.53 D(mCi), with F=12.184 (p<0.01) and DWBC = -2.62 + 0.0757 D (mCi), with F=3.14 (NS). Conclusion: The results suggest that the total absorbed dose is not an absolute predictor of effect, but in this restricted data set a significant predominant effect of the administered dose on toxicity could not be demonstrated either. The data however do not invalidate the theoretical view that 1) with internal radionuclides a large fraction of the total absorbed dose is delivered at very low dose rates, which may be too low for any appreciable effect, and 2) if variation in the kinetics of the agents lead to an adaptation of the administered dose, the initial dose rate is affected. The therapeutic and toxic effects of RIT are probably a function of both the total dose and the dose rate. Further optimization of this therapy needs to take this into consideration

  5. The Hanford Environmental Dose Reconstruction (HEDR) Project: Technical approach

    International Nuclear Information System (INIS)

    Napier, B.A.; Freshley, M.D.; Gilbert, R.O.; Haerer, H.A.; Morgan, L.G.; Rhoads, R.E.; Woodruff, R.K.

    1990-01-01

    Historical measurements and current assessment techniques are being combined to estimate potential radiation doses to people from radioactive releases to the air, the Columbia River, soils, and ground water at the Hanford Site since 1944. Environmental contamination from these releases has been monitored, at varying levels of detail, for 45 yr. Phase I of the Hanford Environmental Reconstruction Project will estimate the magnitude of potential doses, their areal extends, and their associated uncertainties. The Phase I study area comprises 10 counties in eastern Washington and northern Oregon, within a 100-mi radius of the site, including a stretch of the Columbia River that was most significantly affected. These counties contain a range of projected and measured contaminant levels, environmental exposure pathways, and population groups. Phase I dose estimates are being developed for the periods 1944 through 1947 for air pathways and 1964 through 1966 for river pathways. Important radionuclide/pathway combinations include fission products, such as 131 I, in milk for early atmospheric releases and activation products, such as 32 P and 65 Zn, in fish for releases to the river. Potential doses range over several orders of magnitude within the study area. We will expand the time periods and study are in three successive phases, as warranted by results of Phase I

  6. Definitive intraoperative very high-dose radiotherapy for localized osteosarcoma in the extremities

    International Nuclear Information System (INIS)

    Oya, Natsuo; Kokubo, Masaki; Mizowaki, Takashi; Shibamoto, Yuta; Nagata, Yasushi; Sasai, Keisuke; Nishimura, Yasumasa; Tsuboyama, Tadao; Toguchida, Junya; Nakamura, Takashi; Hiraoka, Masahiro

    2001-01-01

    Purpose: To evaluate the outcome and adverse effects in patients with osteosarcoma treated with very high-dose definitive intraoperative radiotherapy (IORT), with the intention of saving the affected limb. Methods and Materials: Thirty-nine patients with osteosarcoma in their extremities were treated with definitive IORT. The irradiation field included the tumor plus an adequate wide margin and excluded the major vessels and nerves. Forty-five to 80 Gy of electrons or X-rays were delivered. The median follow-up of the surviving patients was 124 months. Results: The cause-specific and relapse-free 5-year survival rate was 50% and 43%, respectively. Distant metastasis developed in 23 patients; 19 died and 4 were alive for >10 years. Nine local recurrences were found 4-29 months after IORT in the affected limb. No radiation-induced skin reaction or nerve palsy was observed in the patients treated with X-rays. Experiments using phantoms also confirmed that the scatter dose was below the toxic level in the IORT setting with X-rays. Conclusions: Very high-dose definitive IORT combined with preventive nailing and chemotherapy appeared to be a promising quality-of-life-oriented alternative to treating patients with osteosarcomas in the extremities, although the problem of recurrences from the surrounding unirradiated soft tissue remains to be solved

  7. Dose-reduction techniques for high-dose worker groups in nuclear power plants

    International Nuclear Information System (INIS)

    Khan, T.A.; Baum, J.W.; Dionne, B.J.

    1991-03-01

    This report summarizes the main findings of a study of the extent of radiation dose received by special work groups in the nuclear power industry. Work groups which chronically get large doses were investigated, using information provided by the industry. The tasks that give high doses to these work groups were examined and techniques described that were found to be particularly successful in reducing dose. Quantitative information on the extent of radiation doses to various work groups shows that significant numbers of workers in several critical groups receive doses greater than 1 and even 2 rem per year, particularly contract personnel and workers at BWR-type plants. The number of radiation workers whose lifetime dose is greater than their age is much less. Although the techniques presented would go some way in reducing dose, it is likely that a sizeable reduction to the high-dose work groups may require development of new dose-reduction techniques as well as major changes in procedures. 10 refs., 26 tabs

  8. Methods of assessing total doses integrated across pathways

    International Nuclear Information System (INIS)

    Grzechnik, M.; Camplin, W.; Clyne, F.; Allott, R.; Webbe-Wood, D.

    2006-01-01

    Calculated doses for comparison with limits resulting from discharges into the environment should be summed across all relevant pathways and food groups to ensure adequate protection. Current methodology for assessments used in the radioactivity in Food and the Environment (R.I.F.E.) reports separate doses from pathways related to liquid discharges of radioactivity to the environment from those due to gaseous releases. Surveys of local inhabitant food consumption and occupancy rates are conducted in the vicinity of nuclear sites. Information has been recorded in an integrated way, such that the data for each individual is recorded for all pathways of interest. These can include consumption of foods, such as fish, crustaceans, molluscs, fruit and vegetables, milk and meats. Occupancy times over beach sediments and time spent in close proximity to the site is also recorded for inclusion of external and inhalation radiation dose pathways. The integrated habits survey data may be combined with monitored environmental radionuclide concentrations to calculate total dose. The criteria for successful adoption of a method for this calculation were: Reproducibility can others easily use the approach and reassess doses? Rigour and realism how good is the match with reality?Transparency a measure of the ease with which others can understand how the calculations are performed and what they mean. Homogeneity is the group receiving the dose relatively homogeneous with respect to age, diet and those aspects that affect the dose received? Five methods of total dose calculation were compared and ranked according to their suitability. Each method was labelled (A to E) and given a short, relevant name for identification. The methods are described below; A) Individual doses to individuals are calculated and critical group selection is dependent on dose received. B) Individual Plus As in A, but consumption and occupancy rates for high dose is used to derive rates for application in

  9. Radiation dose rate affects the radiosensitization of MCF-7 and HeLa cell lines to X-rays induced by dextran-coated iron oxide nanoparticles.

    Science.gov (United States)

    Khoshgard, Karim; Kiani, Parvaneh; Haghparast, Abbas; Hosseinzadeh, Leila; Eivazi, Mohammad Taghi

    2017-08-01

    The aim of radiotherapy is to deliver lethal damage to cancerous tissue while preserving adjacent normal tissues. Radiation absorbed dose of the tumoral cells can increase when high atomic nanoparticles are present in them during irradiation. Also, the dose rate is an important aspect in radiation effects that determines the biological results of a given dose. This in vitro study investigated the dose-rate effect on the induced radiosensitivity by dextran-coated iron oxide in cancer cells. HeLa and MCF-7 cells were cultured in vitro and incubated with different concentrations of dextran-coated iron oxide nanoparticles. They were then irradiated with 6 MV photons at dose rates of 43, 185 and 370 cGy/min. The MTT test was used to obtain the cells' survival after 48 h of irradiations. Incubating the cells with the nanoparticles at concentrations of 10, 40 and 80 μg/ml showed no significant cytotoxicity effect. Dextran-coated iron oxide nanoparticles showed more radiosensitivity effect by increasing the dose rate and nanoparticles concentration. Radiosensitization enhancement factors of MCF-7 and HeLa cells at a dose-rate of 370 cGy/min and nanoparticles' concentration of 80 μg/ml were 1.21 ± 0.06 and 1.19 ± 0.04, respectively. Increasing the dose rate of 6 MV photons irradiation in MCF-7 and HeLa cells increases the radiosensitization induced by the dextran-coated iron nanoparticles in these cells.

  10. Low-Dose Ionizing Radiation Affects Mesenchymal Stem Cells via Extracellular Oxidized Cell-Free DNA: A Possible Mediator of Bystander Effect and Adaptive Response

    Directory of Open Access Journals (Sweden)

    V. A. Sergeeva

    2017-01-01

    Full Text Available We have hypothesized that the adaptive response to low doses of ionizing radiation (IR is mediated by oxidized cell-free DNA (cfDNA fragments. Here, we summarize our experimental evidence for this model. Studies involving measurements of ROS, expression of the NOX (superoxide radical production, induction of apoptosis and DNA double-strand breaks, antiapoptotic gene expression and cell cycle inhibition confirm this hypothesis. We have demonstrated that treatment of mesenchymal stem cells (MSCs with low doses of IR (10 cGy leads to cell death of part of cell population and release of oxidized cfDNA. cfDNA has the ability to penetrate into the cytoplasm of other cells. Oxidized cfDNA, like low doses of IR, induces oxidative stress, ROS production, ROS-induced oxidative modifications of nuclear DNA, DNA breaks, arrest of the cell cycle, activation of DNA reparation and antioxidant response, and inhibition of apoptosis. The MSCs pretreated with low dose of irradiation or oxidized cfDNA were equally effective in induction of adaptive response to challenge further dose of radiation. Our studies suggest that oxidized cfDNA is a signaling molecule in the stress signaling that mediates radiation-induced bystander effects and that it is an important component of the development of radioadaptive responses to low doses of IR.

  11. Pb low doses induced genotoxicity in Lactuca sativa plants.

    Science.gov (United States)

    Silva, S; Silva, P; Oliveira, H; Gaivão, I; Matos, M; Pinto-Carnide, O; Santos, C

    2017-03-01

    Soil and water contamination by lead (Pb) remains a topic of great concern, particularly regarding crop production. The admissible Pb values in irrigation water in several countries range from ≈0.1 to ≈5 mg L -1 . In order to evaluate putative effects of Pb within legal doses on crops growth, we exposed Lactuca sativa seeds and seedlings to increasing doses of Pb(NO 3 ) 2 up to 20 mg L -1 . The OECD parameter seed germination and seedling/plant growth were not affected by any of the Pb-concentrations used. However, for doses higher than 5 mg L -1 significant DNA damage was detected: Comet assay detected DNA fragmentation at ≥ 5 mg L -1 and presence of micronuclei (MN) were detected for 20 mg L -1 . Also, cell cycle impairment was observed for doses as low as 0.05 mg L -1 and 0.5 mg L -1 (mostly G 2 arrest). Our data show that for the low doses of Pb used, the OECD endpoints were not able to detect toxicity, while more sensitive endpoints (related with DNA damage and mitotic/interphase disorders) identified genotoxic and cytostatic effects. Furthermore, the nature of the genotoxic effect was dependent on the concentration. Finally, we recommend that MN test and the comet assay should be included as sensitive endpoints in (eco)toxicological assays. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  12. Effects of X-rays spectrum on the dose

    International Nuclear Information System (INIS)

    Rodriguez I, J. L.; Hernandez A, P. L.; Vega C, H. R.; Rivera M, T.

    2015-10-01

    The X-ray equipment for diagnosis comes in different sizes and shapes depending on the scan type to perform. The X-ray spectrum is the energy distribution of the beam photons and consists of a continuous spectrum of photons braking and discrete spectrum due to the characteristic photons. The knowledge of the X-rays spectrum is important to understand like they affect the voltage changes (k Vp), current (m A), time (s) and the type of filter in the interaction mechanisms between X-rays and patient's body, the image receptor or other material that gets in the beam. Across the spectrum can be estimated the absorbed dose in any point of the patient, the quality of the image and the scattered radiation (which is related to the dose received by the equipment operator). The Monte Carlo method was used by MCNP5 code to calculate the spectrum of X-rays that occurs when a monoenergetic electron beam of 250 keV interact with targets of Mo, Rh and W. The spectra were calculated with and without filter, and the values of ambient dose equivalent were estimated, as well as the air kerma. (Author)

  13. Analysis of workers' dose records from the Greek Dose Registry Information System

    International Nuclear Information System (INIS)

    Kamenopoulou, V.; Dimitriou, P.; Proukakis, Ch.

    1995-01-01

    The object of this work is the study of the individual film badge annual dose information of classified workers in Greece, monitored and assessed by the central dosimetry service of the Greek Atomic Energy Commission. Dose summaries were recorded and processed by the Dose Registry Information System. The statistical analysis refers to the years 1989-93 and deals with the distribution of individuals in the occupational groups, the mean annual dose, the collective dose, the distribution of the dose over the different specialties and the number of workers that have exceeded any of the established dose limits. Results concerning the annual dose summaries, demonstrate a year-by-year reduction in the mean individual dose to workers in the health sector. Conversely, exposures in the industrial sector did not show any decreasing tendency during the period under consideration. (Author)

  14. Analysis of the personal doses lower than the reporting level

    International Nuclear Information System (INIS)

    Askounis, P.; Papadomarkaki, E.; Kirgiakou, H.; Dimitropoulou, F.; Carinou, E.; Maltezos, A.; Kamenopoulou, V.

    2008-01-01

    The personnel dosimetry department of Greek Atomic Energy Commission (GAEC) is the only laboratory in the country that assures the individual monitoring of more than 10,500 workers with whole body dosemeters and 100 workers with extremity dosemeters at 1300 establishments. Every year a statistical analysis of the results is performed that provides data for epidemiological studies and assists the evaluation of the radiation protection system of the country. The aim of this study is to perform an analysis of the doses that are lower than the reporting level. The vast majority (92%) of the evaluated H p (10) doses has been reported and recorded as zero. The mean H p (10) (of the non-reported doses) per dosemeter and per monitoring period has been calculated for every geographical department of Greece. The results were compared with the ones produced by the external gamma rate measurements performed by GAEC's telemetric network. The conclusion that can be drawn is that the part of the TL signal of the personal dosemeters is due to the natural background radiation and this can affect the evaluation of the low doses

  15. Gamma-ray mutagenic effect on adzuki bean and the optimum dose

    International Nuclear Information System (INIS)

    Shen Huifang; Li Guozhu

    2012-01-01

    Dry seeds of three kinds of adzuki beans (Jinhong1, Jihong9218, and Jingnong6) were irradiated by 60 Co γ-rays to 100, 200, 300, 400, 500 and 600 Gy. The radiation effects on seedlings were analyzed to estimate the optimum dose, which was 400 to 600 Gy, based on the average half lethal dose (LD 50 ) of 473.3 Gy for the three kinds of adzuki beans. The M 1 γ-ray mutagenic effects were studied by farming the three kinds of adzuki beans irradiated to 350, 500 and 650 Gy. It was found that the beans treated with higher doses had obvious inhibition on germination rate, seedling development, with significant or very significant difference compared with the CK. There was significantly negative correlation between seedling emergences, seedling height and doses. Irradiation affected mature plants by reducing plant height, decreasing nodes number of main stem, pods number per plant, seeds per pod and shortening pod length with significant. The order of radio-sensitivity to γ-rays was as follows: Jinhong1, Jihong9218, and Jingnong6. (authors)

  16. Radial dose distribution of 192Ir and 137Cs seed sources

    International Nuclear Information System (INIS)

    Thomason, C.; Higgins, P.

    1989-01-01

    The radial dose distributions in water around /sup 192/ Ir seed sources with both platinum and stainless steel encapsulation have been measured using LiF thermoluminescent dosimeters (TLD) for distances of 1 to 12 cm along the perpendicular bisector of the source to determine the effect of source encapsulation. Similar measurements also have been made around a /sup 137/ Cs seed source of comparable dimensions. The data were fit to a third order polynomial to obtain an empirical equation for the radial dose factor which then can be used in dosimetry. The coefficients of this equation for each of the three sources are given. The radial dose factor of the stainless steel encapsulated /sup 192/ Ir and that of the platinum encapsulated /sup 192/ Ir agree to within 2%. The radial dose distributions measured here for /sup 192/ Ir with either type of encapsulation and for /sup 137/ Cs are indistinguishable from those of other authors when considering uncertainties involved. For clinical dosimetry based on isotropic point or line source models, any of these equations may be used without significantly affecting accuracy

  17. Dose errors due to charge storage in electron irradiated plastic phantoms

    International Nuclear Information System (INIS)

    Galbraith, D.M.; Rawlinson, J.A.; Munro, P.

    1984-01-01

    Commercial plastics used for radiation dosimetry are good electrical insulators. Used in electron beams, these insulators store charge and produce internal electric fields large enough to measurably alter the electron dose distribution in the plastic. The reading per monitor unit from a cylindrical ion chamber imbedded in a polymethylmethacrylate (PMMA) or polystyrene phantom will increase with accumulated electron dose, the increase being detectable after about 20 Gy of 6-MeV electrons. The magnitude of the effect also depends on the type of the plastic, the thickness of the plastic, the wall thickness of the detector, the diameter and depth of the hole in the plastic, the energy of the electron beam, and the dose rate used. Effects of charge buildup have been documented elsewhere for very low energy electrons at extremely high doses and dose rates. Here we draw attention to the charging effects in plastics at the dose levels encountered in therapy dosimetry where ion chamber or other dosimeter readings may easily increase by 5% to 10% and where a phantom, once charged, will also affect subsequent readings taken in 60 Co beams and high-energy electron and x-ray beams for periods of several days to many months. It is recommended that conducting plastic phantoms replace PMMA and polystyrene phantoms in radiation dosimetry

  18. Anticonvulsant treatment of asphyxiated newborns under hypothermia with lidocaine : efficacy, safety and dosing

    NARCIS (Netherlands)

    van den Broek, Marcel P. H.; Rademaker, Carin M. A.; van Straaten, Henrica L. M.; Huitema, Alwin D. R.; Toet, Mona C.; de Vries, Linda S.; Egberts, Antoine C. G.; Groenendaal, Floris

    BACKGROUND: Lidocaine is an antiarrythmicum used as an anticonvulsant for neonatal seizures, also during therapeutic hypothermia following (perinatal) asphyxia. Hypothermia may affect the efficacy, safety and dosing of lidocaine in these patients. OBJECTIVE: To study the efficacy and safety of

  19. SU-F-I-32: Organ Doses from Pediatric Head CT Scan

    Energy Technology Data Exchange (ETDEWEB)

    Liu, H; Liu, Q; Qiu, J; Zhuo, W [Institute of Radiation Medicine Fudan University, Shanghai (China); Majer, M; Knezevic, Z; Miljanic, S [Radiation Chemistry and Dosimetry Laboratory, Ruder Boskovic Institute, Zagreb (Croatia); Hrsak, H [Clinical Hospital Centre Zagreb, Zagreb (Croatia)

    2016-06-15

    Purpose: To evaluate the organ doses of pediatric patients who undergoing head CT scan using Monte Carlo (MC) simulation and compare it with measurements in anthropomorphic child phantom.. Methods: A ten years old children voxel phantom was developed from CT images, the voxel size of the phantom was 2mm*2mm*2mm. Organ doses from head CT scan were simulated using MCNPX software, 180 detectors were placed in the voxel phantom to tally the doses of the represented tissues or organs. When performing the simulation, 120 kVp and 88 mA were selected as the scan parameters. The scan range covered from the top of the head to the end of the chain, this protocol was used at CT simulator for radiotherapy. To validate the simulated results, organ doses were measured with radiophotoluminescence (RPL) detectors, placed in the 28 organs of the 10 years old CIRS ATOM phantom. Results: The organ doses results matched well between MC simulation and phantom measurements. The eyes dose was showed to be as expected the highest organ dose: 28.11 mGy by simulation and 27.34 mGy by measurement respectively. Doses for organs not included in the scan volume were much lower than those included in the scan volume, thymus doses were observed more than 10 mGy due the CT protocol for radiotherapy covered more body part than routine head CT scan. Conclusion: As the eyes are superficial organs, they may receive the highest radiation dose during the CT scan. Considering the relatively high radio sensitivity, using shielding material or organ based tube current modulation technique should be encouraged to reduce the eye radiation risks. Scan range was one of the most important factors that affects the organ doses during the CT scan. Use as short as reasonably possible scan range should be helpful to reduce the patient radiation dose. This work was supported by the National Natural Science Foundation of China(11475047)

  20. Dose from radiological examinations

    International Nuclear Information System (INIS)

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

    1976-01-01

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

  1. Dose conversion factors

    International Nuclear Information System (INIS)

    Kocher, D.C.; Eckerman, K.F.

    1992-01-01

    The following is discussed in this report: concepts and quantities used in calculating radiation dose from internal and external exposure. Tabulations of dose conversion factor for internal and external exposure to radionuclides. Dose conversion factors give dose per unit intake (internal) or dose per unit concentration in environment (external). Intakes of radionuclides for internal exposure and concentrations of radionuclides in environment for external exposure are assumed to be known. Intakes and concentrations are obtained, e.g., from analyses of environmental transport and exposure pathways. differences between dosimetry methods for radionuclides and hazardous chemicals are highlighted

  2. Physiologic variability at the verge of systemic inflammation: multiscale entropy of heart rate variability is affected by very low doses of endotoxin.

    Science.gov (United States)

    Herlitz, Georg N; Arlow, Renee L; Cheung, Nora H; Coyle, Susette M; Griffel, Benjamin; Macor, Marie A; Lowry, Stephen F; Calvano, Steve E; Gale, Stephen C

    2015-02-01

    Human injury or infection induces systemic inflammation with characteristic neuroendocrine responses. Fluctuations in autonomic function during inflammation are reflected by beat-to-beat variation in heart rate, termed heart rate variability (HRV). In the present study, we determine threshold doses of endotoxin needed to induce observable changes in markers of systemic inflammation, investigate whether metrics of HRV exhibit a differing threshold dose from other inflammatory markers, and investigate the size of data sets required for meaningful use of multiscale entropy (MSE) analysis of HRV. Healthy human volunteers (n = 25) were randomized to receive placebo (normal saline) or endotoxin/lipopolysaccharide (LPS): 0.1, 0.25, 0.5, 1.0, or 2.0 ng/kg administered intravenously. Vital signs were recorded every 30 min for 6 h and then at 9, 12, and 24 h after LPS. Blood samples were drawn at specific time points for cytokine measurements. Heart rate variability analysis was performed using electrocardiogram epochs of 5 min. Multiscale entropy for HRV was calculated for all dose groups to scale factor 40. The lowest significant threshold dose was noted in core temperature at 0.25 ng/kg. Endogenous tumor necrosis factor α and interleukin 6 were significantly responsive at the next dosage level (0.5 ng/kg) along with elevations in circulating leukocytes and heart rate. Responses were exaggerated at higher doses (1 and 2 ng/kg). Time domain and frequency domain HRV metrics similarly suggested a threshold dose, differing from placebo at 1.0 and 2.0 ng/kg, below which no clear pattern in response was evident. By applying repeated-measures analysis of variance across scale factors, a significant decrease in MSE was seen at 1.0 and 2.0 ng/kg by 2 h after exposure to LPS. Although not statistically significant below 1.0 ng/kg, MSE unexpectedly decreased across all groups in an orderly dose-response pattern not seen in the other outcomes. By using repeated-measures analysis of

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Abdollahi, Hamid, E-mail: Hamid_rbp@yahoo.com [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Shiri, Isaac [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Salimi, Yazdan [Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Sarebani, Maghsoud; Mehdinia, Reza [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Deevband, Mohammad Reza [Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Mahdavi, Seied Rabi [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Radiation Biology Research Center, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Sohrabi, Ahmad [Department of Biostatistics, School of Public Health, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Bitarafan-Rajabi, Ahmad, E-mail: bitarafan@hotmail.com [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Department of Nuclear Medicine, Rajaei Cardiovascular, Medical and Research Center, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2016-12-15

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

  5. [Examination of patient dose reduction in cardiovasucular X-ray systems with a metal filter].

    Science.gov (United States)

    Yasuda, Mitsuyoshi; Kato, Kyouichi; Tanabe, Nobuaki; Sakiyama, Koushi; Uchiyama, Yushi; Suzuki, Yoshiaki; Suzuki, Hiroshi; Nakazawa, Yasuo

    2012-01-01

    In interventional X-ray for cardiology of flat panel digital detector (FPD), the phenomenon that exposure dose was suddenly increased when a subject thickness was thickened was recognized. At that time, variable metal built-in filters in FPD were all off. Therefore, we examined whether dose reduction was possible without affecting a clinical image using metal filter (filter) which we have been conventionally using for dose reduction. About 45% dose reduction was achieved when we measured an exposure dose at 30 cm of acrylic thickness in the presence of a filter. In addition, we measured signal to noise ratio/contrast to noise ratio/a resolution limit by the visual evaluation, and there was no influence by filter usage. In the clinical examination, visual evaluation of image quality of coronary angiography (40 cases) using a 5-point evaluation scale by a physician was performed. As a result, filter usage did not influence the image quality (p=NS). Therefore, reduction of sudden increase of exposure dose was achieved without influencing an image quality by adding filter to FPD.

  6. On dose distribution comparison

    International Nuclear Information System (INIS)

    Jiang, Steve B; Sharp, Greg C; Neicu, Toni; Berbeco, Ross I; Flampouri, Stella; Bortfeld, Thomas

    2006-01-01

    In radiotherapy practice, one often needs to compare two dose distributions. Especially with the wide clinical implementation of intensity-modulated radiation therapy, software tools for quantitative dose (or fluence) distribution comparison are required for patient-specific quality assurance. Dose distribution comparison is not a trivial task since it has to be performed in both dose and spatial domains in order to be clinically relevant. Each of the existing comparison methods has its own strengths and weaknesses and there is room for improvement. In this work, we developed a general framework for comparing dose distributions. Using a new concept called maximum allowed dose difference (MADD), the comparison in both dose and spatial domains can be performed entirely in the dose domain. Formulae for calculating MADD values for various comparison methods, such as composite analysis and gamma index, have been derived. For convenience in clinical practice, a new measure called normalized dose difference (NDD) has also been proposed, which is the dose difference at a point scaled by the ratio of MADD to the predetermined dose acceptance tolerance. Unlike the simple dose difference test, NDD works in both low and high dose gradient regions because it considers both dose and spatial acceptance tolerances through MADD. The new method has been applied to a test case and a clinical example. It was found that the new method combines the merits of the existing methods (accurate, simple, clinically intuitive and insensitive to dose grid size) and can easily be implemented into any dose/intensity comparison tool

  7. Radiation dose reduction for CT assessment of urolithiasis using iterative reconstruction. A prospective intra-individual study

    Energy Technology Data Exchange (ETDEWEB)

    Harder, Annemarie M. den; Willemink, Martin J.; Wessels, Frank J.; Schilham, Arnold M.R.; Leiner, Tim; Jong, Pim A. de [Utrecht University Medical Center, Department of Radiology, Utrecht (Netherlands); Doormaal, Pieter J. van; Budde, Ricardo P.J. [Erasmus Medical Center, Department of Radiology, Rotterdam (Netherlands); Lock, M.T.W.T. [University Medical Center, Department of Urology, Utrecht (Netherlands)

    2018-01-15

    To assess the performance of hybrid (HIR) and model-based iterative reconstruction (MIR) in patients with urolithiasis at reduced-dose computed tomography (CT). Twenty patients scheduled for unenhanced abdominal CT for follow-up of urolithiasis were prospectively included. Routine dose acquisition was followed by three low-dose acquisitions at 40%, 60% and 80% reduced doses. All images were reconstructed with filtered back projection (FBP), HIR and MIR. Urolithiasis detection rates, gall bladder, appendix and rectosigmoid evaluation and overall subjective image quality were evaluated by two observers. 74 stones were present in 17 patients. Half the stones were not detected on FBP at the lowest dose level, but this improved with MIR to a sensitivity of 100%. HIR resulted in a slight decrease in sensitivity at the lowest dose to 72%, but outperformed FBP. Evaluation of other structures with HIR at 40% and with MIR at 60% dose reductions was comparable to FBP at routine dose, but 80% dose reduction resulted in non-evaluable images. CT radiation dose for urolithiasis detection can be safely reduced by 40 (HIR)-60 (MIR) % without affecting assessment of urolithiasis, possible extra-urinary tract pathology or overall image quality. (orig.)

  8. Low-dose ultraviolet-B irradiation of donor corneal endothelium and graft survival

    International Nuclear Information System (INIS)

    Dana, M.R.; Olkowski, S.T.; Ahmadian, H.; Stark, W.J.; Young, E.M.

    1990-01-01

    Donor rabbit corneal endothelium was pretreated with different doses of ultraviolet (UV-B) irradiation (302 nm) before grafting to test whether allograft survival could be favorably affected in comparison with untreated corneas grafted into the same recipients. Endothelial rejection was observed in 19 of 32 (59%) eyes that received no treatment compared with five of 32 (16%) eyes that received UV-B (P less than 0.001), and increasing doses of UV-B were associated with lower rejection rates (P less than 0.05). Although exposure of donor endothelium significantly reduced endothelial rejection at all doses tested, it resulted in primary graft failure in a substantial proportion of corneas treated at high doses. Class II (Ia) antigen staining of corneal tissue was present in conjunction with clinical evidence of rejection, and the magnitude of staining correlated with the histologic extent of inflammation. Scanning electron microscopy revealed various endothelial cell surface irregularities and membrane defects in high-dose UV-treated corneas. Endothelial cell cultures exposed in vitro to UV-B light showed a dose-dependent loss in cell viability. These data suggest that UV-B pretreatment of donor corneal endothelium prolongs graft survival but that toxic side effects must be carefully controlled

  9. Radiation Dose to Newborns in Neonatal Intensive Care Units

    International Nuclear Information System (INIS)

    Bahreyni Toossi, M. T.; Malekzadeh, M.

    2012-01-01

    With the increase of X-ray use for medical diagnostic purposes, knowing the given doses is necessary in patients for comparison with reference levels. The concept of reference doses or diagnostic reference levels has been developed as a practical aid in the optimization of patient protection in diagnostic radiology. To assess the radiation doses to neonates from diagnostic radiography (chest and abdomen). This study has been carried out in the neonatal intensive care unit of a province in Iran. Entrance surface dose was measured directly with thermoluminescent dosimeters. The population included 195 neonates admitted for a diagnostic radiography, in eight NICUs of different hospital types. The mean entrance surface dose for chest and abdomen examinations were 76.3 μGy and 61.5 μGy, respectively. Diagnostic reference levels for neonate in NICUs of the province were 88 μGy for chest and 98 μGy for abdomen examinations that were slightly higher than other studies. Risk of death due to radiation cancer incidence of abdomens examination was equal to 1.88 × 10 -6 for male and 4.43 × 10 -6 for female. For chest X-ray, it was equal to 2.54 × 10 -6 for male and 1.17 × 10 -5 for female patients. Diagnostic reference levels for neonates in our province were slightly higher than values reported by other studies such as European national diagnostic reference levels and the NRPB reference dose. The main reason was related to using a high mAs and a low kVp applied in most departments and also a low focus film distance. Probably lack of collimation also affected some exams in the NICUs.

  10. Tissue classifications in Monte Carlo simulations of patient dose for photon beam tumor treatments

    Science.gov (United States)

    Lin, Mu-Han; Chao, Tsi-Chian; Lee, Chung-Chi; Tung-Chieh Chang, Joseph; Tung, Chuan-Jong

    2010-07-01

    The purpose of this work was to study the calculated dose uncertainties induced by the material classification that determined the interaction cross-sections and the water-to-material stopping-power ratios. Calculations were made for a head- and neck-cancer patient treated with five intensity-modulated radiotherapy fields using 6 MV photon beams. The patient's CT images were reconstructed into two voxelized patient phantoms based on different CT-to-material classification schemes. Comparisons of the depth-dose curve of the anterior-to-posterior field and the dose-volume-histogram of the treatment plan were used to evaluate the dose uncertainties from such schemes. The results indicated that any misassignment of tissue materials could lead to a substantial dose difference, which would affect the treatment outcome. To assure an appropriate material assignment, it is desirable to have different conversion tables for various parts of the body. The assignment of stopping-power ratio should be based on the chemical composition and the density of the material.

  11. Comparison of organ doses in human phantoms: variations due to body size and posture

    International Nuclear Information System (INIS)

    Feng, Xu; Xiang-Hong, Jia; Xue-Jun, Yu; Zhan-Chun, Pan; Qian, Liu; Chun-Xin, Yang

    2017-01-01

    Organ dose calculations performed using human phantoms can provide estimates of astronauts' health risks due to cosmic radiation. However, the characteristics of such phantoms strongly affect the estimation precision. To investigate organ dose variations with body size and posture in human phantoms, a non-uniform rational B-spline boundary surfaces model was constructed based on cryo-section images. This model was used to establish four phantoms with different body size and posture parameters, whose organs parameters were changed simultaneously and which were voxelised with 4x4x4 mm"3 resolution. Then, using Monte Carlo transport code, the organ doses caused by ≤500 MeV isotropic incident protons were calculated. The dose variations due to body size differences within a certain range were negligible, and the doses received in crouching and standing-up postures were similar. Therefore, a standard Chinese phantom could be established, and posture changes cannot effectively protect astronauts during solar particle events. (authors)

  12. Tissue classifications in Monte Carlo simulations of patient dose for photon beam tumor treatments

    International Nuclear Information System (INIS)

    Lin, Mu-Han; Chao, Tsi-Chian; Lee, Chung-Chi; Tung-Chieh Chang, Joseph; Tung, Chuan-Jong

    2010-01-01

    The purpose of this work was to study the calculated dose uncertainties induced by the material classification that determined the interaction cross-sections and the water-to-material stopping-power ratios. Calculations were made for a head- and neck-cancer patient treated with five intensity-modulated radiotherapy fields using 6 MV photon beams. The patient's CT images were reconstructed into two voxelized patient phantoms based on different CT-to-material classification schemes. Comparisons of the depth-dose curve of the anterior-to-posterior field and the dose-volume-histogram of the treatment plan were used to evaluate the dose uncertainties from such schemes. The results indicated that any misassignment of tissue materials could lead to a substantial dose difference, which would affect the treatment outcome. To assure an appropriate material assignment, it is desirable to have different conversion tables for various parts of the body. The assignment of stopping-power ratio should be based on the chemical composition and the density of the material.

  13. Variable effects of high-dose adrenaline relative to standard-dose adrenaline on resuscitation outcomes according to cardiac arrest duration.

    Science.gov (United States)

    Jeung, Kyung Woon; Ryu, Hyun Ho; Song, Kyung Hwan; Lee, Byung Kook; Lee, Hyoung Youn; Heo, Tag; Min, Yong Il

    2011-07-01

    Adjustment of adrenaline (epinephrine) dosage according to cardiac arrest (CA) duration, rather than administering the same dose, may theoretically improve resuscitation outcomes. We evaluated variable effects of high-dose adrenaline (HDA) relative to standard-dose adrenaline (SDA) on resuscitation outcomes according to CA duration. Twenty-eight male domestic pigs were randomised to the following 4 groups according to the dosage of adrenaline (SDA 0.02 mg/kg vs. HDA 0.2mg/kg) and duration of CA before beginning cardiopulmonary resuscitation (CPR): 6 min SDA, 6 min HDA, 13 min SDA, or 13 min HDA. After the predetermined duration of untreated ventricular fibrillation, CPR was provided. All animals in the 6 min SDA, 6 min HDA, and 13 min HDA groups were successfully resuscitated, while only 4 of 7 pigs in the 13 min SDA group were successfully resuscitated (p=0.043). HDA groups showed higher right atrial pressure, more frequent ventricular ectopic beats, higher blood glucose, higher troponin-I, and more severe metabolic acidosis than SDA groups. Animals of 13 min groups showed more severe metabolic acidosis and higher troponin-I than animals of 6 min groups. All successfully resuscitated animals, except two animals in the 13 min HDA group, survived for 7 days (p=0.121). Neurologic deficit score was not affected by the dose of adrenaline. HDA showed benefit in achieving restoration of spontaneous circulation in 13 min CA, when compared with 6 min CA. However, this benefit did not translate into improved long-term survival or neurologic outcome. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  14. Critical dose and toxicity index of organs at risk in radiotherapy: Analyzing the calculated effects of modified dose fractionation in non–small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Pedicini, Piernicola, E-mail: ppiern@libero.it [Service of Medical Physics, I.R.C.C.S. Regional Cancer Hospital C.R.O.B, Rionero in Vulture (Italy); Strigari, Lidia [Laboratory of Medical Physics and Expert Systems, Regina Elena National Cancer Institute, Rome (Italy); Benassi, Marcello [Service of Medical Physics, Scientific Institute of Tumours of Romagna I.R.S.T., Meldola (Italy); Caivano, Rocchina [Service of Medical Physics, I.R.C.C.S. Regional Cancer Hospital C.R.O.B, Rionero in Vulture (Italy); Fiorentino, Alba [U.O. of Radiotherapy, I.R.C.C.S. Regional Cancer Hospital C.R.O.B., Rionero in Vulture (Italy); Nappi, Antonio [U.O. of Nuclear Medicine, I.R.C.C.S. Regional Cancer Hospital C.R.O.B., Rionero in Vulture (Italy); Salvatore, Marco [U.O. of Nuclear Medicine, I.R.C.C.S. SDN Foundation, Naples (Italy); Storto, Giovanni [U.O. of Nuclear Medicine, I.R.C.C.S. Regional Cancer Hospital C.R.O.B., Rionero in Vulture (Italy)

    2014-04-01

    To increase the efficacy of radiotherapy for non–small cell lung cancer (NSCLC), many schemes of dose fractionation were assessed by a new “toxicity index” (I), which allows one to choose the fractionation schedules that produce less toxic treatments. Thirty-two patients affected by non resectable NSCLC were treated by standard 3-dimensional conformal radiotherapy (3DCRT) with a strategy of limited treated volume. Computed tomography datasets were employed to re plan by simultaneous integrated boost intensity-modulated radiotherapy (IMRT). The dose distributions from plans were used to test various schemes of dose fractionation, in 3DCRT as well as in IMRT, by transforming the dose-volume histogram (DVH) into a biological equivalent DVH (BDVH) and by varying the overall treatment time. The BDVHs were obtained through the toxicity index, which was defined for each of the organs at risk (OAR) by a linear quadratic model keeping an equivalent radiobiological effect on the target volume. The less toxic fractionation consisted in a severe/moderate hyper fractionation for the volume including the primary tumor and lymph nodes, followed by a hypofractionation for the reduced volume of the primary tumor. The 3DCRT and IMRT resulted, respectively, in 4.7% and 4.3% of dose sparing for the spinal cord, without significant changes for the combined-lungs toxicity (p < 0.001). Schedules with reduced overall treatment time (accelerated fractionations) led to a 12.5% dose sparing for the spinal cord (7.5% in IMRT), 8.3% dose sparing for V{sub 20} in the combined lungs (5.5% in IMRT), and also significant dose sparing for all the other OARs (p < 0.001). The toxicity index allows to choose fractionation schedules with reduced toxicity for all the OARs and equivalent radiobiological effect for the tumor in 3DCRT, as well as in IMRT, treatments of NSCLC.

  15. The shape of the cancer mortality dose-response curve for atomic bomb survivors

    International Nuclear Information System (INIS)

    Pierce, D.A.; Vaeth, M.

    1989-10-01

    The shape of the cancer mortality dose-response in the atomic bomb survivor data is analyzed in the context of linear-quadratic (LQ) models. Results are given for all cancers except leukemia as a group, for leukemia, and for combined inferences assuming common curvature. Since there is substantial information aside from these data suggesting a dose-response concave from above, the emphasis here is not on estimating the best-fitting dose-response curve, but rather on assessing the maximal extent of curvature under LQ models which is consistent with the data. Such inferences are substantially affected by imprecision in the dose estimates, and methods are applied which make explicit allowances for biases due to this. The primary means used here to express the extent of curvature is the factor by which linear risk estimates should be divided to arrive at appropriate low-dose risk estimates. In the past, influential committees have recommended ranges of 2-10 and of 1.5-3 for such a factor. Results here suggest that values greater than about 2 are at least moderately inconsistent with these data, within the context of LQ models. It is emphasized, however, that there is little direct information in these data regarding low-dose risks; the inferences here depend strongly on the link between low-dose and high-dose risks provided by the assumption of an LQ model. (author)

  16. Measurement of high dose rates of 60Co by gamma activation of115In and 111Cd foils

    International Nuclear Information System (INIS)

    Haddad, Kh; Qattan, M.; Taleb, A.

    2009-12-01

    The high gamma dose rate measurement technique using nuclear reaction (γ,(γ ' ') was introduced in this work. This technique is cheap, easy, reliable, and independent of chemical and physical factors, which affect other techniques. The response to the absorbed dose in this technique is linear and can be used for high dose. Cd and In foils were irradiated using 60 Co source and the resulted isomer activities were measured using gamma spectrometer. These foils were calibrated to be used as dosemeter and its results were compared with conventional one. The dose distribution in the irradiation field was determined using In foils. (authors)

  17. Patient dose measurement and dose reduction in East Anglia (UK)

    International Nuclear Information System (INIS)

    Wade, J.P.; Goldstone, K.E.; Dendy, P.P.

    1995-01-01

    At the end of 1990 a programme of patient dose measurements was introduced as part of the quality assurance service already provided for X ray departments throughout the East Anglian Health Region (UK). Thermoluminescence dosemeters (TLDs) were used to measure over 1200 skin entrance surface doses for four common radiographic views in 33 hospitals in both the NHS and private sector. The four views were chosen to cover a wide range of equipment and techniques. The data collected have enabled Regional reference doses to be set which, for all views considered, fall below the National Radiological Protection Board (NRPB) Reference levels. In departments which exceeded reference levels, techniques were reviewed, improvements suggested and doses re-measured, in accordance with the recommended procedure for patient dose audit. A significant finding was that, given appropriate controls, X ray departments in the private sector could achieve the same acceptably low doses as NHS departments. (Author)

  18. Suitability of sterin dose indicators for control of certain food irradiation processes

    International Nuclear Information System (INIS)

    Sattar, Abdus; Ahmad, Anwar; Iqbal, Mohammad Zafar

    1999-01-01

    Sterin indicator, a new label dosimeter was evaluated for reliability and suitability as a device for discriminating and monitoring radiation treatment. Two versions, Sterin-125 and Sterin-300 were irradiated with gamma rays at dose ranges of 75-175 Gy and 200-400 Gy respectively. The irradiated samples were evaluated subjectively using Multiple Comparison Difference technique and their stability was tested under dark and differing light and temperature conditions. The results showed that these Sterin labels are generally reliable and useful but are affected by doses lower than designated threshold and by extended exposure to light sources

  19. Dependence of total dose response of bipolar linear microcircuits on applied dose rate

    International Nuclear Information System (INIS)

    McClure, S.; Will, W.; Perry, G.; Pease, R.L.

    1994-01-01

    The effect of dose rate on the total dose radiation hardness of three commercial bipolar linear microcircuits is investigated. Total dose tests of linear bipolar microcircuits show larger degradation at 0.167 rad/s than at 90 rad/s even after the high dose rate test is followed by a room temperature plus a 100 C anneal. No systematic correlation could be found for degradation at low dose rate versus high dose rate and anneal. Comparison of the low dose rate with the high dose rate anneal data indicates that MIL-STD-883, method 1019.4 is not a worst-case test method when applied to bipolar microcircuits for low dose rate space applications

  20. Effect of sub-sterilizing doses of gamma radiation on Spodoptera frugiperda (Smith) pupae

    International Nuclear Information System (INIS)

    Duarte Aguilar, J.A.; Arthur, Valter

    1998-01-01

    Studies were undertaken to verify the effects of sub-sterilizing doses of gamma radiations on pupae of Spodoptera frugiperda (Smith) and transfer of genetic heredity on the first and second generations. Statistical analysis showed difference in the ageing effect of gamma radiations on the larval phase and larval viability ranged between 72 and 94 percent, when irradiated (50 Gy) males or females were crossed with non-irradiated adults. With doses of 100, 125, 150 and 175 Gy the crossing of irradiated males x non irradiated females the larval viability was between 64 and 94 per cent in F-1 and F-2 generations. The duration and other life parameters of the pupae and adults did not differ from the controls. The egg laying ability was not affected by doses up to 150 Gy on both the sexes. If irradiated females with doses of 175 and 200 Gy were crossed with non-irradiated males, the egg laying was inhibited when males were irradiated with one of these doses, the offspring females did not lay eggs or laid non-fertile eggs. (author)

  1. Investigation of organ dose difference of age phantoms for medical X-ray examinations

    International Nuclear Information System (INIS)

    Park, Sang Hyun; Kim, Woo Ran; Lee, Jai Ki; Lee, Choon Sik

    2003-01-01

    Methodology for calculating the organ equivalent doses and the effective doses of pediatric and adult patients undergoing medical X-ray examinations were established. The MIRD-type mathematical phantoms of 4 age groups were constructed with addition of the esophagus to the same phantoms. Two typical examination procedures, chest PA and abdomen AP, were simulated for the pediatric patients as well as the adult as illustrative examples. The results confirmed that patients pick up approximate 0.03 mSv of effective dose from a single chest PA examination, and 0.4 to 1.7 mSv from an abdomen AP examination depending on the ages. For dose calculations where irradiation is made with a limited field, the details of the position, size and shape of the organs and the organ depth from the entrance surface considerably affect the resulting doses. Therefore, it is important to optimize radiation protection by control of X-ray properties and beam examination field. The calculation result, provided in this study, can be used to implement optimization for medical radiation protection

  2. The effect of dose protraction on the incidence of lung carcinomas in beagle dogs with internally deposited β-emitting radionuclides

    International Nuclear Information System (INIS)

    Griffith, W.C.; Boecker, B.B.; Hahn, F.F.; Muggenburg, B.A.; Snipes, M.B.

    1992-01-01

    Studies using Beagle dogs were conducted to understand health effects when lung is the primary organ irradiated after inhaling insoluble radioactive particles containing one of four β-emitting radionuclides, 90 Y, 91 Y, 144 Ce, or 90 Sr. The low-LET β irradiation was delivered over a wide range of total doses and dose rate patterns that protracted the dose to lung from about 1 wk to several years. The tumor incidence rates for lung carcinomas were estimated using a proportional hazard rate model. These studies suggest that dose protraction only affects production of lung carcinomas at doses above 50 Gy

  3. A novel method for the evaluation of uncertainty in dose-volume histogram computation.

    Science.gov (United States)

    Henríquez, Francisco Cutanda; Castrillón, Silvia Vargas

    2008-03-15

    Dose-volume histograms (DVHs) are a useful tool in state-of-the-art radiotherapy treatment planning, and it is essential to recognize their limitations. Even after a specific dose-calculation model is optimized, dose distributions computed by using treatment-planning systems are affected by several sources of uncertainty, such as algorithm limitations, measurement uncertainty in the data used to model the beam, and residual differences between measured and computed dose. This report presents a novel method to take them into account. To take into account the effect of associated uncertainties, a probabilistic approach using a new kind of histogram, a dose-expected volume histogram, is introduced. The expected value of the volume in the region of interest receiving an absorbed dose equal to or greater than a certain value is found by using the probability distribution of the dose at each point. A rectangular probability distribution is assumed for this point dose, and a formulation that accounts for uncertainties associated with point dose is presented for practical computations. This method is applied to a set of DVHs for different regions of interest, including 6 brain patients, 8 lung patients, 8 pelvis patients, and 6 prostate patients planned for intensity-modulated radiation therapy. Results show a greater effect on planning target volume coverage than in organs at risk. In cases of steep DVH gradients, such as planning target volumes, this new method shows the largest differences with the corresponding DVH; thus, the effect of the uncertainty is larger.

  4. High dose vitamin D may improve lower urinary tract symptoms in postmenopausal women.

    Science.gov (United States)

    Oberg, Johanna; Verelst, Margareta; Jorde, Rolf; Cashman, Kevin; Grimnes, Guri

    2017-10-01

    Lower urinary tract symptoms (LUTS) are common in postmenopausal women, and have been reported inversely associated with vitamin D intake and serum 25-hydroxyvitamin D (25(OH)D) levels. The aim of this study was to investigate if high dose vitamin D supplementation would affect LUTS in comparison to standard dose. In a randomized controlled study including 297 postmenopausal women with low bone mineral density, the participants were allocated to receive capsules of 20 000IU of vitamin D 3 twice a week (high dose group) or similar looking placebo (standard dose group). In addition, all the participants received 1g of calcium and 800IU of vitamin D daily. A validated questionnaire regarding LUTS was filled in at baseline and after 12 months. At baseline, 76 women in the high dose group and 82 in the standard dose group reported any LUTS. Levels of serum 25(OH)D increased significantly more in the high dose group (from 64.7 to 164.1nmol/l compared to from 64.1 to 81.8nmol/l, p<0.01). No differences between the groups were seen regarding change in LUTS except for a statistically significant reduction in the reported severity of urine incontinence in the high dose group as compared to the standard dose group after one year (p<0.05). The results need confirmation in a study specifically designed for this purpose. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Pain and mean absorbed dose to the pubic bone after radiotherapy among gynecological cancer survivors.

    Science.gov (United States)

    Waldenström, Ann-Charlotte; Olsson, Caroline; Wilderäng, Ulrica; Dunberger, Gail; Lind, Helena; al-Abany, Massoud; Palm, Åsa; Avall-Lundqvist, Elisabeth; Johansson, Karl-Axel; Steineck, Gunnar

    2011-07-15

    To analyze the relationship between mean absorbed dose to the pubic bone after pelvic radiotherapy for gynecological cancer and occurrence of pubic bone pain among long-term survivors. In an unselected, population-based study, we identified 823 long-term gynecological cancer survivors treated with pelvic radiotherapy during 1991-2003. For comparison, we used a non-radiation-treated control population of 478 matched women from the Swedish Population Register. Pain, intensity of pain, and functional impairment due to pain in the pubic bone were assessed with a study-specific postal questionnaire. We analyzed data from 650 survivors (participation rate 79%) with median follow-up of 6.3 years (range, 2.3-15.0 years) along with 344 control women (participation rate, 72 %). Ten percent of the survivors were treated with radiotherapy; ninety percent with surgery plus radiotherapy. Brachytherapy was added in 81%. Complete treatment records were recovered for 538/650 survivors, with dose distribution data including dose-volume histograms over the pubic bone. Pubic bone pain was reported by 73 survivors (11%); 59/517 (11%) had been exposed to mean absorbed external beam doses beam doses ≥ 52.5 Gy. Thirty-three survivors reported pain affecting sleep, a 13-fold increased prevalence compared with control women. Forty-nine survivors reported functional impairment measured as pain walking indoors, a 10-fold increased prevalence. Mean absorbed external beam dose above 52.5 Gy to the pubic bone increases the occurrence of pain in the pubic bone and may affect daily life of long-term survivors treated with radiotherapy for gynecological cancer. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Pain and Mean Absorbed Dose to the Pubic Bone After Radiotherapy Among Gynecological Cancer Survivors

    International Nuclear Information System (INIS)

    Waldenstroem, Ann-Charlotte; Olsson, Caroline; Wilderaeng, Ulrica; Dunberger, Gail; Lind, Helena; Al-Abany, Massoud; Palm, Asa; Avall-Lundqvist, Elisabeth; Johansson, Karl-Axel; Steineck, Gunnar

    2011-01-01

    Purpose: To analyze the relationship between mean absorbed dose to the pubic bone after pelvic radiotherapy for gynecological cancer and occurrence of pubic bone pain among long-term survivors. Methods and Materials: In an unselected, population-based study, we identified 823 long-term gynecological cancer survivors treated with pelvic radiotherapy during 1991-2003. For comparison, we used a non-radiation-treated control population of 478 matched women from the Swedish Population Register. Pain, intensity of pain, and functional impairment due to pain in the pubic bone were assessed with a study-specific postal questionnaire. Results: We analyzed data from 650 survivors (participation rate 79%) with median follow-up of 6.3 years (range, 2.3-15.0 years) along with 344 control women (participation rate, 72 %). Ten percent of the survivors were treated with radiotherapy; ninety percent with surgery plus radiotherapy. Brachytherapy was added in 81%. Complete treatment records were recovered for 538/650 survivors, with dose distribution data including dose-volume histograms over the pubic bone. Pubic bone pain was reported by 73 survivors (11%); 59/517 (11%) had been exposed to mean absorbed external beam doses <52.5 Gy to the pubic bone and 5/12 (42%) to mean absorbed external beam doses ≥52.5 Gy. Thirty-three survivors reported pain affecting sleep, a 13-fold increased prevalence compared with control women. Forty-nine survivors reported functional impairment measured as pain walking indoors, a 10-fold increased prevalence. Conclusions: Mean absorbed external beam dose above 52.5 Gy to the pubic bone increases the occurrence of pain in the pubic bone and may affect daily life of long-term survivors treated with radiotherapy for gynecological cancer.

  7. Insignificant levels of dose

    International Nuclear Information System (INIS)

    Webb, G.A.M.; McLean, A.S.

    1977-01-01

    The procedures recommended by the International Commission on Radiological Protection (ICRP) for making decisions concerning controllable sources of radiation exposure of the public include 'justification' and 'optimisation'. The tool recommended by the ICRP for reaching these decisions is collective dose or dose commitment supplemented by consideration of doses to individuals. In both these considerations the practical problem arises of whether very small doses to large numbers of people should contribute to the final decision-making process. It may be that at levels of dose which are small increments on natural background, the relationship between dose and effect is linear even though the slope may be close to zero. If so, collective dose is a meaningful concept and the calculation of total detriment for the purpose of justification could legitimately include all doses. In the calculation of collective doses for the purpose of optimisation, which involves decisions on how much money or resource should be allocated to dose reduction, it is necessary to appraise radiation detriment realistically. At low levels of dose to the individual such as those small by comparison with variations in natural background within the UK, the risk to the individual is such that his well-being will not be significantly changed by the presence or absence of the radiation dose. These small doses, which are well below the point at which an individual attaches significance, should not carry a societal significance. Societal acceptance of risk is analysed with a view to assessing a level of possible risk, and hence dose, below which resources should not in general be diverted to secure further reduction. A formulation for collective dose commitment is proposed incorporating a cut-off to exclude insignificant doses. The implications of this formulation in practical situations are discussed

  8. Case Example of Dose Optimization Using Data From Bortezomib Dose-Finding Clinical Trials.

    Science.gov (United States)

    Lee, Shing M; Backenroth, Daniel; Cheung, Ying Kuen Ken; Hershman, Dawn L; Vulih, Diana; Anderson, Barry; Ivy, Percy; Minasian, Lori

    2016-04-20

    The current dose-finding methodology for estimating the maximum tolerated dose of investigational anticancer agents is based on the cytotoxic chemotherapy paradigm. Molecularly targeted agents (MTAs) have different toxicity profiles, which may lead to more long-lasting mild or moderate toxicities as well as to late-onset and cumulative toxicities. Several approved MTAs have been poorly tolerated during long-term administration, leading to postmarketing dose optimization studies to re-evaluate the optimal treatment dose. Using data from completed bortezomib dose-finding trials, we explore its toxicity profile, optimize its dose, and examine the appropriateness of current designs for identifying an optimal dose. We classified the toxicities captured from 481 patients in 14 bortezomib dose-finding studies conducted through the National Cancer Institute Cancer Therapy Evaluation Program, computed the incidence of late-onset toxicities, and compared the incidence of dose-limiting toxicities (DLTs) among groups of patients receiving different doses of bortezomib. A total of 13,008 toxicities were captured: 46% of patients' first DLTs and 88% of dose reductions or discontinuations of treatment because of toxicity were observed after the first cycle. Moreover, for the approved dose of 1.3 mg/m(2), the estimated cumulative incidence of DLT was > 50%, and the estimated cumulative incidence of dose reduction or treatment discontinuation because of toxicity was nearly 40%. When considering the entire course of treatment, the approved bortezomib dose exceeds the conventional ceiling DLT rate of 20% to 33%. Retrospective analysis of trial data provides an opportunity for dose optimization of MTAs. Future dose-finding studies of MTAs should take into account late-onset toxicities to ensure that a tolerable dose is identified for future efficacy and comparative trials. © 2016 by American Society of Clinical Oncology.

  9. Characteristics of 3D gamma evaluation according to phantom rotation error and dose gradient

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyeong Hyun; Kim, Dong Su; Kim, Tae Ho; Kang, Seong Hee; Shin, Dong Seok; Noh, Yu Yoon; Suh, Tae Seok [Dept. of Biomedical Engineering, Research Institute of Biomedical Engineering, College of Medicine, the Catholic University of Korea, Seoul (Korea, Republic of); Cho, Min Seok [Dept. of Radiation Oncology, Asan Medical Center, Seoul (Korea, Republic of)

    2016-12-15

    In intensity modulated radiation therapy (IMRT) quality assurance (QA) using dosimetric phantom, a spatial uncertainty induced from phantom set-up inevitably occurs and gamma index that is used to evaluate IMRT plan quality can be affected differently by a combination of the spatial uncertainty and magnitude of dose gradient. In this study, we investigated the impacts of dose gradient and the phantom set-up error on 3D gamma evaluation. In this study, we investigated the characteristics of gamma evaluation according to dose gradient and phantom rotation axis. As a result, 3D gamma had better performance than 2D gamma. Therefore, it can be useful for IMRT QA analysis at clinical field.

  10. Significance of BETA and GAMMA dose on environmental qualification of components

    International Nuclear Information System (INIS)

    Aydogdu, K.M.; Tsang, K.T.

    1999-01-01

    Safety-related systems and components that are required to perform safety functions during accident conditions must be designed to withstand the harsh environmental conditions that occur as a consequence of the accident. Where these conditions are 'harsh', and equipment operability can potentially be affected by the post-accident environment environmental qualification of the equipment must be conducted to demonstrate that the required safety function can be maintained. It is also understood that non-safety related equipment that affects, or prevents, the satisfactory operation of a safety-related system should also withstand the 'harsh' environmental conditions caused by an appropriate design-basis accident. There are essentially two types of requirements that must be satisfied to qualify equipment or components to withstand radiation damage, namely economic requirements and safety requirements. The general objective of the economic requirement is to reduce maintenance cost and to maximize component life during reactor operation. The general objective of the safety requirement is that the equipment should be qualified to withstand the harsh post-accident environmental conditions and should function properly for the appropriate length of time after a design-basis accident has occurred. To address the economic factors - i.e., to reduce maintenance costs and to maximize component life - the radiation dose rates to equipment are calculated throughout the reactor building and the service building during reactor operation. These are also used for the safety requirement purpose, to assess radiation ageing of safety-related components caused by degradation of material properties with time at radiation exposure. To address the safety requirement, the dose-rate estimates and accumulated doses after a LOCA coincident with loss-of-emergency-core cooling (LOECC) are provided. The harsh post-accident environmental conditions defined for environmental qualification of components

  11. Dosing Accuracy of Insulin Aspart FlexPens After Transport Through the Pneumatic Tube System.

    Science.gov (United States)

    Ward, Leah G; Heckman, Michael G; Warren, Amy I; Tran, Kimberly

    2013-01-01

    The purpose of this study was to evaluate whether transporting insulin aspart FlexPens via a pneumatic tube system affects the dosing accuracy of the pens. A total of 115 Novo Nordisk FlexPens containing insulin aspart were randomly assigned to be transported via a pneumatic tube system (n = 92) or to serve as the control (n = 23). Each pen was then randomized to 10 international unit (IU) doses (n = 25) or 30 IU doses (n = 67), providing 600 and 603 doses, respectively, for the pneumatic tube group. The control group also received random assignment to 10 IU doses (n = 6) or 30 IU doses (n = 17), providing 144 and 153 doses, respectively. Each dose was expelled using manufacturer instructions. Weights were recorded, corrected for specific gravity, and evaluated based on acceptable International Organization for Standardization (ISO) dosing limits. In the group of pens transported through the pneumatic tube system, none of the 600 doses of 10 IU (0.0%; 95% CI, 0.0 to 0.6) and none of the 603 doses of 30 IU (0.0%; 95% CI, 0.0 to 0.6) fell outside of the range of acceptable weights. Correspondingly, in the control group, none of the 144 doses at 10 IU (0.0%; 95% CI, 0.0 to 2.5) and none of the 153 doses at 30 IU (0.0%; 95% CI, 0.0 to 2.4) were outside of acceptable ISO limits. Transportation via pneumatic tube system does not appear to compromise dosing accuracy. Hospital pharmacies may rely on the pneumatic tube system for timely and accurate transport of insulin aspart FlexPens.

  12. Occupational Doses and the Contribution to the Population Dose in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Han, Seung Jae; Kyu, Hwan Jeong [KINS, Daejeon (Korea, Republic of)

    2016-05-15

    The purpose of this study is to evaluate the occupational exposure records in terms of the control of exposure for radiation workers and dose reduction. The study includes the estimates of the number of people exposed occupationally, the effective collective doses and mean doses to those exposed. In addition, the study includes an estimate of the contribution of occupational exposure to the Korean population dose. The exposure of radiation workers in occupational field includes medical radiology, industrial applications such as radiography, nuclear power, and some research activities. Occupational exposure from medical radiology practices includes the contributions from diagnostic x-ray procedures, dental radiography, nuclear medicine and radiation therapy. The control of exposure for radiation workers, and the measures necessary to maintain radiation exposure as low as reasonably achievable (ALARA) are specified in Subparagraph 3 and Subparagraph 4 of Article 91 (1) of the Korea Nuclear Safety Act (KNSA), respectively. Therefore, from a regulatory perspective, the exposure data of the workers are primarily for verification of the adequacy of the control of exposure, radiation protection and implementation of ALARA. The number of people exposed occupationally, the effective collective doses and mean doses to those exposed, and average effective doses from occupational exposure during the period of 2009 to 2013 have been evaluated. In general, radiation workers were increasing in number annually, but the mean doses for those exposed each year showed the control of exposures were mostly considered met within the dose limit in KNSA. Nevertheless, it was shown that the continuous efforts would be needed to reduce doses and thus to implement ALARA regulatory requirements. In radiation occupations, the application of ICRP radiation protection principles will ensure good practice and decreasing exposures. Over the period of 5 years, the contributions of the annual

  13. Occupational Doses and the Contribution to the Population Dose in Korea

    International Nuclear Information System (INIS)

    Han, Seung Jae; Kyu, Hwan Jeong

    2016-01-01

    The purpose of this study is to evaluate the occupational exposure records in terms of the control of exposure for radiation workers and dose reduction. The study includes the estimates of the number of people exposed occupationally, the effective collective doses and mean doses to those exposed. In addition, the study includes an estimate of the contribution of occupational exposure to the Korean population dose. The exposure of radiation workers in occupational field includes medical radiology, industrial applications such as radiography, nuclear power, and some research activities. Occupational exposure from medical radiology practices includes the contributions from diagnostic x-ray procedures, dental radiography, nuclear medicine and radiation therapy. The control of exposure for radiation workers, and the measures necessary to maintain radiation exposure as low as reasonably achievable (ALARA) are specified in Subparagraph 3 and Subparagraph 4 of Article 91 (1) of the Korea Nuclear Safety Act (KNSA), respectively. Therefore, from a regulatory perspective, the exposure data of the workers are primarily for verification of the adequacy of the control of exposure, radiation protection and implementation of ALARA. The number of people exposed occupationally, the effective collective doses and mean doses to those exposed, and average effective doses from occupational exposure during the period of 2009 to 2013 have been evaluated. In general, radiation workers were increasing in number annually, but the mean doses for those exposed each year showed the control of exposures were mostly considered met within the dose limit in KNSA. Nevertheless, it was shown that the continuous efforts would be needed to reduce doses and thus to implement ALARA regulatory requirements. In radiation occupations, the application of ICRP radiation protection principles will ensure good practice and decreasing exposures. Over the period of 5 years, the contributions of the annual

  14. Low-dose computed tomography image restoration using previous normal-dose scan

    International Nuclear Information System (INIS)

    Ma, Jianhua; Huang, Jing; Feng, Qianjin; Zhang, Hua; Lu, Hongbing; Liang, Zhengrong; Chen, Wufan

    2011-01-01

    Purpose: In current computed tomography (CT) examinations, the associated x-ray radiation dose is of a significant concern to patients and operators. A simple and cost-effective means to perform the examinations is to lower the milliampere-seconds (mAs) or kVp parameter (or delivering less x-ray energy to the body) as low as reasonably achievable in data acquisition. However, lowering the mAs parameter will unavoidably increase data noise and the noise would propagate into the CT image if no adequate noise control is applied during image reconstruction. Since a normal-dose high diagnostic CT image scanned previously may be available in some clinical applications, such as CT perfusion imaging and CT angiography (CTA), this paper presents an innovative way to utilize the normal-dose scan as a priori information to induce signal restoration of the current low-dose CT image series. Methods: Unlike conventional local operations on neighboring image voxels, nonlocal means (NLM) algorithm utilizes the redundancy of information across the whole image. This paper adapts the NLM to utilize the redundancy of information in the previous normal-dose scan and further exploits ways to optimize the nonlocal weights for low-dose image restoration in the NLM framework. The resulting algorithm is called the previous normal-dose scan induced nonlocal means (ndiNLM). Because of the optimized nature of nonlocal weights calculation, the ndiNLM algorithm does not depend heavily on image registration between the current low-dose and the previous normal-dose CT scans. Furthermore, the smoothing parameter involved in the ndiNLM algorithm can be adaptively estimated based on the image noise relationship between the current low-dose and the previous normal-dose scanning protocols. Results: Qualitative and quantitative evaluations were carried out on a physical phantom as well as clinical abdominal and brain perfusion CT scans in terms of accuracy and resolution properties. The gain by the use

  15. The effects of periphyton, fish and fertilizer dose on biological processes affecting water quality in earthen fish ponds.

    NARCIS (Netherlands)

    Milstein, A.; Azim, M.E.; Wahab, M.A.; Verdegem, M.C.J.

    2003-01-01

    The potential of periphyton-based aquaculture in South Asia is under investigation in an extensive research program. This paper is a further analysis of data from four experiments carried out in that framework, to explore periphyton, fish and fertilizer dose effects on water quality. Factor analysis

  16. Conversion from tooth enamel dose to organ doses for electron spin resonance dosimetry

    International Nuclear Information System (INIS)

    Takahashi, Fumiaki; Yamaguchi, Yasuhiro; Saito, Kimiaki; Hamada, Tatsuji

    2002-01-01

    Conversion from tooth enamel dose to organ doses was analyzed to establish a method of retrospective individual dose assessment against external photon exposure by electron spin resonance (ESR) dosimetry. Dose to tooth enamel was obtained by Monte Carlo calculations using a modified MIRD-type phantom with a teeth part. The calculated tooth enamel doses were verified by measurements with thermo-luminescence dosimeters inserted in a physical head phantom. Energy and angular dependences of tooth enamel dose were compared with those of other organ doses. Additional Monte Carlo calculations were performed to study the effect of human model on the tooth enamel dose with a voxel-type phantom, which was based on computed tomography images of the physical phantom. The data derived with the modified MIRD-type phantom were applied to convert from tooth enamel dose to organ doses against external photon exposure in a hypothesized field, where scattered radiation was taken into account. The results indicated that energy distribution of photons incident to a human body is required to evaluate precisely an individual dose based on ESR dosimetry for teeth. (author)

  17. Methodology for setting the reference levels in the measurements of the dose rate absorbed in air due to the environmental gamma radiation

    International Nuclear Information System (INIS)

    Dominguez Ley, Orlando; Capote Ferrera, Eduardo; Caveda Ramos, Celia; Alonso Abad, Dolores

    2008-01-01

    Full text: The methodology for setting the reference levels of the measurements of the gamma dose rate absorbed in the air is described. The registration level was obtained using statistical methods. To set the alarm levels, it was necessary to begin with certain affectation level, which activates the investigation operation mode when being reached. It is was necessary to transform this affectation level into values of the indicators selected to set the appearance of an alarm in the network, allowing its direct comparison and at the same time a bigger operability of this one. The affectation level was assumed as an effective dose of 1 mSv/y, which is the international dose limit for public. The conversion factor obtained in a practical way as a consequence of the Chernobyl accident was assumed, converting the value of annual effective dose into values of effective dose rate in air. These factors are the most important in our work, since the main task of the National Network of Environmental Radiological Surveillance of the Republic of Cuba is detecting accidents with a situations regional affectation, and this accident is precisely an example of pollution at this scale. The alarm level setting was based on the results obtained in the first year of the Chernobyl accident. For this purpose, some transformations were achieved. In the final results, a correction factor was introduced depending on the year season the measurement was made. It was taken into account the influence of different meteorological events on the measurement of this indicator. (author)

  18. Implications of dose limit modification for radioactive installations dedicated to research

    International Nuclear Information System (INIS)

    Lumbreras, J.M.; Fernandez, G.M.; Marana, D.

    1992-01-01

    The reduced dose limits proposed in the ICRP recommendations affect the Spanish Regulations on Sanitary Protection against Ionizing Radiation. Some implications of this for radioactive installations dedicated to research are pointed out. A very simple statistical study shows that dosimetric data might be used to adopt new criteria for classification of personnel, and even of working areas. (author)

  19. The effects of glucose dose and dual-task performance on memory for emotional material.

    Science.gov (United States)

    Brandt, Karen R; Sünram-Lea, Sandra I; Jenkinson, Paul M; Jones, Emma

    2010-07-29

    Whilst previous research has shown that glucose administration can boost memory performance, research investigating the effects of glucose on memory for emotional material has produced mixed findings. Whereas some research has shown that glucose impairs memory for emotional material, other research has shown that glucose has no effect on emotional items. The aim of the present research was therefore to provide further investigation of the role of glucose on the recognition of words with emotional valence by exploring effects of dose and dual-task performance, both of which affect glucose facilitation effects. The results replicated past research in showing that glucose administration, regardless of dose or dual-task conditions, did not affect the memorial advantage enjoyed by emotional material. This therefore suggests an independent relationship between blood glucose levels and memory for emotional material. Copyright 2010 Elsevier B.V. All rights reserved.

  20. Identification of Differential Gene Expression Patterns after Acute Exposure to High and Low Doses of Low-LET Ionizing Radiation in a Reconstituted Human Skin Tissue

    Energy Technology Data Exchange (ETDEWEB)

    Tilton, Susan C.; Markillie, Lye Meng; Hays, Spencer; Taylor, Ronald C.; Stenoien, David L.

    2016-11-01

    Our goal here was to identify dose and temporal dependent radiation responses in a complex tissue, reconstituted human skin. Direct sequencing of RNA (RNA-seq) was used to quantify altered transcripts following exposure to 0.1, 2 and 10 Gy of ionizing radiation at 3 and 8 hours. These doses include a low dose in the range of some medical diagnostic procedures (0.1 Gy), a dose typically received during radiotherapy (2.0 Gy) and a lethal dose (10 Gy). These doses could be received after an intentional or accidental radiation exposure and biomarkers are needed to rapidly and accurately triage exposed individuals. A total of 1701 genes were deemed to be significantly affected by high dose radiation exposure with the majority of genes affected at 10 Gy. A group of 29 genes including GDF15, BBC3, PPM1D, FDXR, GADD45A, MDM2, CDKN1A, TP53INP1, CYCSP27, SESN1, SESN2, PCNA, and AEN were similarly altered at both 2 and 10 Gy, but not 0.1 Gy, at multiple time points. A much larger group of up regulated genes, including those involved in inflammatory responses, was significantly altered only after a 10 Gy exposure. At high doses, down regulated genes were associated with cell cycle regulation and exhibited an apparent linear response between 2 and 10 Gy. While only a handful of genes were significantly affected by 0.1 Gy exposure using stringent statistical filters, groups of related genes regulating cell cycle progression and inflammatory responses consistently exhibited opposite trends in their regulation compared to the high dose exposures. Differential regulation of PLK1 signaling at low and high doses was confirmed using qRT-PCR. These results indicate that some alterations in gene expression are qualitatively different at low and high doses of radiation in this model system.

  1. When is a dose not a dose?

    International Nuclear Information System (INIS)

    Green, Patrick

    1992-01-01

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

  2. Effects of a reduced dose of injected iron on health, iron status and growth of suckling piglets with access to iron enriched soil.

    Science.gov (United States)

    Thanner, S; Gutzwiller, A

    2018-02-01

    The effects of the recommended dose of 200 mg iron and of half that dose injected on the first day of life on health, iron status and performance during the 4 week suckling period were studied in 2'123 piglets. All piglets received creep feed and soil which was supplemented with 14 g iron per kg. Neither mortality nor the prevalence of arthritis, meningitis and foot abscess (each disease affecting about 1% of the piglets) differed between the two groups. The low dose of 100 mg iron decreased blood haemoglobin concentration at weaning (110 ± 19 vs.120 ± 15 g/l), but did not affect growth rate.

  3. Protection of protein A-sepharose columns irradiated to sterilization doses

    International Nuclear Information System (INIS)

    Moore, J.S.; Power, D.M.; Tallentire, A.

    1996-01-01

    The effects of ionizing radiation on protein A-sepharose mini columns have been investigated. Radiolysis to a dose of 25 kGy is accompanied by a 55% loss of binding capacity to IgG. Various OH· radical scavengers have been used to render them radiation resistantat the high doses commonly used for the purpose of sterilization. Inclusion of mannitol at high concentrations (1 mol dm -3 ) partially protects the columns as does ascorbate (10 - 2 mol dm -3 ), the loss of binding being only ∼ 15% at 25 kGy. The mixture of mannitol (1 mol dm -3 ) and ascorbate (10 -2 mol dm -3 ) however protects to ∼5% decomposition. This value is not affected by the presence of oxygen at the beginning of irradiation. (Author)

  4. Determination of Entrance Skin Doses and Organ Doses for Medical X Ray Examinations

    International Nuclear Information System (INIS)

    Tung, C.J.; Cheng, C.Y.; Chao, T.C.; Tsai, H.Y.

    1999-01-01

    A national survey of patient doses for diagnostic X ray radiographs is planned in Taiwan. Entrance skin doses and organ doses for all installed X ray machines will be investigated. A pilot study has been carried out for the national survey to develop a protocol for the dose assessment. Entrance skin doses and organ doses were measured by thermoluminescence dosemeters and calculated by Monte Carlo simulations for several X ray examinations. The conversion factor from free air entrance absorbed dose to entrance skin dose was derived. A formula for the computation of entrance skin doses from inputs of kV p , mA.s, source to skin distance, aluminium filtration, and generator rectifying was constructed. Organ doses were measured using a RANDO phantom and calculated using a mathematical phantom. All data will be passed to the Atomic Energy Council for developing a programme of national survey and regulatory controls for diagnostic X ray examinations. (author)

  5. Monte Carlo dose calculations for phantoms with hip prostheses

    International Nuclear Information System (INIS)

    Bazalova, M; Verhaegen, F; Coolens, C; Childs, P; Cury, F; Beaulieu, L

    2008-01-01

    Computed tomography (CT) images of patients with hip prostheses are severely degraded by metal streaking artefacts. The low image quality makes organ contouring more difficult and can result in large dose calculation errors when Monte Carlo (MC) techniques are used. In this work, the extent of streaking artefacts produced by three common hip prosthesis materials (Ti-alloy, stainless steel, and Co-Cr-Mo alloy) was studied. The prostheses were tested in a hypothetical prostate treatment with five 18 MV photon beams. The dose distributions for unilateral and bilateral prosthesis phantoms were calculated with the EGSnrc/DOSXYZnrc MC code. This was done in three phantom geometries: in the exact geometry, in the original CT geometry, and in an artefact-corrected geometry. The artefact-corrected geometry was created using a modified filtered back-projection correction technique. It was found that unilateral prosthesis phantoms do not show large dose calculation errors, as long as the beams miss the artefact-affected volume. This is possible to achieve in the case of unilateral prosthesis phantoms (except for the Co-Cr-Mo prosthesis which gives a 3% error) but not in the case of bilateral prosthesis phantoms. The largest dose discrepancies were obtained for the bilateral Co-Cr-Mo hip prosthesis phantom, up to 11% in some voxels within the prostate. The artefact correction algorithm worked well for all phantoms and resulted in dose calculation errors below 2%. In conclusion, a MC treatment plan should include an artefact correction algorithm when treating patients with hip prostheses

  6. Evaluation of a low-dose neonatal chest radiographic system

    International Nuclear Information System (INIS)

    Burton, E.M.; Kirks, D.R.; Strife, J.L.; Henry, G.C.; Kereiakes, J.G.

    1988-01-01

    A new low-dose chest radiographic system for use in the neonatal nursery was evaluated. This test system, composed of a Du Pont Kevlar fiber-front cassette, Quanta fast-detail screen, Cronex 4L film (wide latitude), and additional yttrium filtration (0.1 mm), reduced the radiation dose in neonatal chest radiography by 69% (0.9 vs 2.9 mrad [0.009 vs 0.029 mGy]) as compared with a conventional system without added yttrium filtration; the thyroid dose was reduced by 76% (0.9 vs 3.7 mrad [0.009 vs 0.037 mGy]). The cumulative dose reduction was achieved through a combination of factors, including (1) beam hardening by the added yttrium filter, (2) increased X-ray transmission through the Kevlar cassette, and (3) a fast film-screen combination. Scatter radiation at distances of 1 and 6 ft. (0.3 and 1.8 m) was negligible for both systems. Image sharpness was compared for the conventional system with and without added yttrium filtration and for the Kevlar system with yttrium. Although sharpness of bony detail was unchanged by adding yttrium filtration to the conventional system, a decrease in sharpness was noted with the Kevlar system. Because image sharpness was affected in the test system, we are not using the Kevlar-Cronex 4L system for mobile chest radiography in the neonatal intensive care unit, despite dose reductions. However, further study is recommended to determine if there is a slower film-screen combination with yttrium filtration that will not degrade image sharpness

  7. Gamma-ray dose rate increase at rainfall events and their air-mass origins

    International Nuclear Information System (INIS)

    Iyogi, Takashi; Hisamatsu, Shun'ichi; Inaba, Jiro

    2007-01-01

    The environmental γ-ray dose rate and precipitation rates were measured at our institute, in Rokkasho, Aomori, Japan. We analyzed 425 rainfall events in which the precipitation rate was over 0.5 mm from April through November during the years 2003 to 2005. Backward trajectories for 5 d starting from 1000 m above Rokkasho at the time of the maximum dose rate in a rainfall event, were calculated by using the HYSPLIT model of the NOAA Air Resources Laboratory. The trajectories for 5 d were classified by visual inspection according to the passage areas; Pacific Ocean, Asian Continent and Japan Islands. The increase of cumulative environmental γ-ray dose during a rainfall event was plotted against the precipitation in the event, and their relationship was separately examined according to the air-mass passage area, i.e. origin of the air-mass. Our results showed that the origin of air-mass was an important factor affecting the increase of environmental γ-ray dose rate by rainfall. (author)

  8. TH-C-18A-09: Exam and Patient Parameters Affecting the DNA Damage Response Following CT Studies

    International Nuclear Information System (INIS)

    Elgart, S; Adibi, A; Bostani, M; Ruehm, S; Enzmann, D; McNitt-Gray, M; Iwamoto, K

    2014-01-01

    Purpose: To identify exam and patient parameters affecting the biological response to CT studies using in vivo and ex vivo blood samples. Methods: Blood samples were collected under IRB approval from 16 patients undergoing clinically-indicated CT exams. Blood was procured prior to, immediately after and 30minutes following irradiation. A sample of preexam blood was placed on the patient within the exam region for ex vivo analysis. Whole blood samples were fixed immediately following collection and stained for γH2AX to assess DNA damage response (DDR). Median fluorescence of treated samples was compared to non-irradiated control samples for each patient. Patients were characterized by observed biological kinetic response: (a) fast — phosphorylation increased by 2minutes and fell by 30minutes, (b) slow — phosphorylation continued to increase to 30minutes and (c) none — little change was observed or irradiated samples fell below controls. Total dose values were normalized to exam time for an averaged dose-rate in dose/sec for each exam. Relationships between patient biological responses and patient and exam parameters were investigated. Results: A clearer dose response at 30minutes is observed for young patients (<61yoa; R2>0.5) compared to old patients (>61yoa; R 2 <0.11). Fast responding patients were significantly younger than slow responding patients (p<0.05). Unlike in vivo samples, age did not significantly affect the patient response ex vivo. Additionally, fast responding patients received exams with significantly smaller dose-rate than slow responding patients (p<0.05). Conclusion: Age is a significant factor in the biological response suggesting that DDR may be more rapid in a younger population and slower as the population ages. Lack of an agerelated response ex vivo suggests a systemic response to radiation not present when irradiated outside the body. Dose-rate affects the biological response suggesting that patient response may be related to scan

  9. Dose planning objectives in anal canal cancer IMRT: the TROG ANROTAT experience

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Elizabeth, E-mail: elizabeth@mebrown.net [Princess Alexandra Hospital, Brisbane, Queensland (Australia); Cray, Alison [Peter MacCallum Cancer Cancer Centre, Box Hill, Victoria (Australia); Haworth, Annette [Peter MacCallum Cancer Cancer Centre, Box Hill, Victoria (Australia); University of Melbourne, Melbourne, Victoria (Australia); Chander, Sarat [Peter MacCallum Cancer Cancer Centre, Box Hill, Victoria (Australia); Lin, Robert [Medica Oncology, Hurstville, New South Wales (Australia); Subramanian, Brindha; Ng, Michael [Radiation Oncology Victoria, Melbourne, Victoria (Australia); Princess Alexandra Hospital, Brisbane, Queensland (Australia)

    2015-06-15

    Intensity modulated radiotherapy (IMRT) is ideal for anal canal cancer (ACC), delivering high doses to irregular tumour volumes whilst minimising dose to surrounding normal tissues. Establishing achievable dose objectives is a challenge. The purpose of this paper was to utilise data collected in the Assessment of New Radiation Oncology Treatments and Technologies (ANROTAT) project to evaluate the feasibility of ACC IMRT dose planning objectives employed in the Australian situation. Ten Australian centres were randomly allocated three data sets from 15 non-identifiable computed tomography data sets representing a range of disease stages and gender. Each data set was planned by two different centres, producing 30 plans. All tumour and organ at risk (OAR) contours, prescription and dose constraint details were provided. Dose–volume histograms (DVHs) for each plan were analysed to evaluate the feasibility of dose planning objectives provided. All dose planning objectives for the bone marrow (BM) and femoral heads were achieved. Median planned doses exceeded one or more objectives for bowel, external genitalia and bladder. This reached statistical significance for bowel V30 (P = 0.04), V45 (P < 0.001), V50 (P < 0.001), external genitalia V20 (P < 0.001) and bladder V35 (P < 0.001), V40 (P = 0.01). Gender was found to be the only significant factor in the likelihood of achieving the bowel V50 (P = 0.03) and BM V30 constraints (P = 0.04). The dose planning objectives used in the ANROTAT project provide a good starting point for ACC IMRT planning. To facilitate clinical implementation, it is important to prioritise OAR objectives and recognise factors that affect the achievability of these objectives.

  10. Laser-based irradiation apparatus and method to measure the functional dose-rate response of semiconductor devices

    Science.gov (United States)

    Horn, Kevin M [Albuquerque, NM

    2008-05-20

    A broad-beam laser irradiation apparatus can measure the parametric or functional response of a semiconductor device to exposure to dose-rate equivalent infrared laser light. Comparisons of dose-rate response from before, during, and after accelerated aging of a device, or from periodic sampling of devices from fielded operational systems can determine if aging has affected the device's overall functionality. The dependence of these changes on equivalent dose-rate pulse intensity and/or duration can be measured with the apparatus. The synchronized introduction of external electrical transients into the device under test can be used to simulate the electrical effects of the surrounding circuitry's response to a radiation exposure while exposing the device to dose-rate equivalent infrared laser light.

  11. Occupational dose constraint

    International Nuclear Information System (INIS)

    Heilbron Filho, Paulo Fernando Lavalle; Xavier, Ana Maria

    2005-01-01

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

  12. Automated size-specific CT dose monitoring program: Assessing variability in CT dose

    International Nuclear Information System (INIS)

    Christianson, Olav; Li Xiang; Frush, Donald; Samei, Ehsan

    2012-01-01

    Purpose: The potential health risks associated with low levels of ionizing radiation have created a movement in the radiology community to optimize computed tomography (CT) imaging protocols to use the lowest radiation dose possible without compromising the diagnostic usefulness of the images. Despite efforts to use appropriate and consistent radiation doses, studies suggest that a great deal of variability in radiation dose exists both within and between institutions for CT imaging. In this context, the authors have developed an automated size-specific radiation dose monitoring program for CT and used this program to assess variability in size-adjusted effective dose from CT imaging. Methods: The authors radiation dose monitoring program operates on an independent health insurance portability and accountability act compliant dosimetry server. Digital imaging and communication in medicine routing software is used to isolate dose report screen captures and scout images for all incoming CT studies. Effective dose conversion factors (k-factors) are determined based on the protocol and optical character recognition is used to extract the CT dose index and dose-length product. The patient's thickness is obtained by applying an adaptive thresholding algorithm to the scout images and is used to calculate the size-adjusted effective dose (ED adj ). The radiation dose monitoring program was used to collect data on 6351 CT studies from three scanner models (GE Lightspeed Pro 16, GE Lightspeed VCT, and GE Definition CT750 HD) and two institutions over a one-month period and to analyze the variability in ED adj between scanner models and across institutions. Results: No significant difference was found between computer measurements of patient thickness and observer measurements (p= 0.17), and the average difference between the two methods was less than 4%. Applying the size correction resulted in ED adj that differed by up to 44% from effective dose estimates that were not

  13. SU-E-T-192: Commissioning of a Commercial 3D Dose Calculation Program

    International Nuclear Information System (INIS)

    Langen, K; Guerrero, M; Xu, H; Zhou, J; Zhang, B; Chen, S; Killefer, M

    2015-01-01

    Purpose: To commission a commercial software package (CSP) that is used as secondary dose calculation check. The CSP uses an independent golden data beam model. However, some parameters can be modified to generate a customer specific model. Plan comparisons and point dose measurements were performed to test if and to what extent the beam model needed adjustment to optimize results. Methods: Beam parameter configurations were compared between the CSP and both TPS. Twelve phantom test plans ranging from simple to complex were generated in two treatment planning systems (TPS). Tests included small field, off axis, EDW, IMRT and VMAT plans. For each plan a point dose was measured to establish ground truth. Lastly, patient plans were compared for both TPS systems and the CSP. Results: Beam parameters agreed within 2%. The output factors for small fields were changed for the 15 MV beam by 2 and 1.5 % for the 1 cm and 2 cm field sizes, respectively. For the 6 MV beam output factors were adjusted by 3−0.8% for field sizes ranging from 1 to 5 cm. The MLC dynamic leaf gap was adjusted by 1.5 mm for 18 MV beam. Differences between the CSP and the TPS were noted in the built-up region. These differences affected the gamma pass rate in the surface region, however this effect is reduced with increasing number of beam angles and does not affect point dose calculations at depth. All IMRT and VMAT plans agreed with the CSP using a gamma pass rate of 95% (3%, 3mm). Conclusion: The CSP is used to verify point doses for all 3D plans generated in our clinic for the last 6 months. No point dose mismatches were encountered since the CSP was implemented. Next, the CSP will be adapted for secondary checks of all IMRT plans. KL had a beta tester agreement with Mobius Medical for an in-kind equipment and software loan

  14. SU-E-T-192: Commissioning of a Commercial 3D Dose Calculation Program

    Energy Technology Data Exchange (ETDEWEB)

    Langen, K; Guerrero, M; Xu, H; Zhou, J; Zhang, B; Chen, S [University of Maryland School of Medicine, Baltimore, MD (United States); Killefer, M [Hastings College, Hastings, Nebraska (United States)

    2015-06-15

    Purpose: To commission a commercial software package (CSP) that is used as secondary dose calculation check. The CSP uses an independent golden data beam model. However, some parameters can be modified to generate a customer specific model. Plan comparisons and point dose measurements were performed to test if and to what extent the beam model needed adjustment to optimize results. Methods: Beam parameter configurations were compared between the CSP and both TPS. Twelve phantom test plans ranging from simple to complex were generated in two treatment planning systems (TPS). Tests included small field, off axis, EDW, IMRT and VMAT plans. For each plan a point dose was measured to establish ground truth. Lastly, patient plans were compared for both TPS systems and the CSP. Results: Beam parameters agreed within 2%. The output factors for small fields were changed for the 15 MV beam by 2 and 1.5 % for the 1 cm and 2 cm field sizes, respectively. For the 6 MV beam output factors were adjusted by 3−0.8% for field sizes ranging from 1 to 5 cm. The MLC dynamic leaf gap was adjusted by 1.5 mm for 18 MV beam. Differences between the CSP and the TPS were noted in the built-up region. These differences affected the gamma pass rate in the surface region, however this effect is reduced with increasing number of beam angles and does not affect point dose calculations at depth. All IMRT and VMAT plans agreed with the CSP using a gamma pass rate of 95% (3%, 3mm). Conclusion: The CSP is used to verify point doses for all 3D plans generated in our clinic for the last 6 months. No point dose mismatches were encountered since the CSP was implemented. Next, the CSP will be adapted for secondary checks of all IMRT plans. KL had a beta tester agreement with Mobius Medical for an in-kind equipment and software loan.

  15. Cranial CT with adaptive statistical iterative reconstruction: improved image quality with concomitant radiation dose reduction.

    Science.gov (United States)

    Rapalino, O; Kamalian, Shervin; Kamalian, Shahmir; Payabvash, S; Souza, L C S; Zhang, D; Mukta, J; Sahani, D V; Lev, M H; Pomerantz, S R

    2012-04-01

    To safeguard patient health, there is great interest in CT radiation-dose reduction. The purpose of this study was to evaluate the impact of an iterative-reconstruction algorithm, ASIR, on image-quality measures in reduced-dose head CT scans for adult patients. Using a 64-section scanner, we analyzed 100 reduced-dose adult head CT scans at 6 predefined levels of ASIR blended with FBP reconstruction. These scans were compared with 50 CT scans previously obtained at a higher routine dose without ASIR reconstruction. SNR and CNR were computed from Hounsfield unit measurements of normal GM and WM of brain parenchyma. A blinded qualitative analysis was performed in 10 lower-dose CT datasets compared with higher-dose ones without ASIR. Phantom data analysis was also performed. Lower-dose scans without ASIR had significantly lower mean GM and WM SNR (P = .003) and similar GM-WM CNR values compared with higher routine-dose scans. However, at ASIR levels of 20%-40%, there was no statistically significant difference in SNR, and at ASIR levels of ≥60%, the SNR values of the reduced-dose scans were significantly higher (P ASIR levels of ≥40% (P ASIR levels ≥60% (P ASIR in adult head CT scans reduces image noise and increases low-contrast resolution, while allowing lower radiation doses without affecting spatial resolution.

  16. Radiation doses for Marshall Islands Atolls affected by U.S. nuclear testing: all exposure pathways, remedial measures, and environmental loss of (137)Cs.

    Science.gov (United States)

    Robison, William L; Hamilton, Terry F

    2010-01-01

    Radiation doses calculated for people resettling Bikini Island at Bikini Atoll, Enjebi Island at Enewetak Atoll, Rongelap Island at Rongelap Atoll, and Utrōk Island at Utrōk Atoll are presented. Residence is assumed to begin in 2010. In previous dose assessments it was shown that (137)Cs accounts for about 98% of the total dose for returning residents. About 85 to 90% (depending on the atoll) is via consumption of locally grown foods containing (137)Cs, and about 10 to 15% is due to external exposure from (137)Cs in the soil. These assessments were made using only the radiological half-life of (137)Cs (30.1 y). We have shown since that there is an environmental loss of (137)Cs from soil to groundwater that results in a more rapid loss of (137)Cs from the atoll ecosystem. The mean effective half-life of (137)Cs at the atolls is 8.5 y. Moreover, treatment of coconut trees with potassium (K) reduces (137)Cs concentration in drinking coconut meat at Bikini Atoll to about 5% of pretreatment concentrations. The magnitude of reduction is dependent on the concentration of (137)Cs in soil, and thereby in food crops, and is less for Enjebi and Rongelap Islands than for Bikini Island. Treatment of food crops and fruit trees with K and removal of the top 15 cm of soil around houses and community buildings prior to construction to reduce external exposure where people spend most of their time has been presented to the communities as a "Combined Option" remediation strategy. Doses presented here are calculated using the Combined Option, effective half-life of (137)Cs at the atolls, and a diet of both imported and local foods. The average natural background dose in the Marshall Islands, plus the anthropogenic nuclear test-related dose at Bikini, Enjebi, and Rongelap Islands, is less for each of the islands than the average background dose in the U.S. and Europe.

  17. Feasibility study on an integrated AEC-grid device for the optimization of image quality and exposure dose in mammography

    Science.gov (United States)

    Kim, Kyo-Tae; Yun, Ryang-Young; Han, Moo-Jae; Heo, Ye-Ji; Song, Yong-Keun; Heo, Sung-Wook; Oh, Kyeong-Min; Park, Sung-Kwang

    2017-10-01

    Currently, in the radiation diagnosis field, mammography is used for the early detection of breast cancer. In addition, studies are being conducted on a grid to produce high-quality images. Although the grid ratio of the grid, which affects the scattering removal rate, must be increased to improve image quality, it increases the total exposure dose. While the use of automatic exposure control is recommended to minimize this problem, existing mammography equipment, unlike general radiography equipment, is mounted on the back of a detector. Therefore, the device is greatly affected by the detector and supporting device, and it is difficult to control the exposure dose. Accordingly, in this research, an integrated AEC-grid device that simultaneously performs AEC and grid functions was used to minimize the unnecessary exposure dose while removing scattering, thereby realizing superior image quality.

  18. Quality of fresh-cut Iceberg lettuce and spinach irradiated at doses up to 4 kGy

    International Nuclear Information System (INIS)

    Fan Xuetong; Guan Wenqiang; Sokorai, Kimberly J.B.

    2012-01-01

    Fresh-cut Iceberg lettuce packaged in modified atmosphere packages and spinach in perforated film bags were irradiated with gamma rays at doses of 0, 1, 2, 3, and 4 kGy. After irradiation, the samples were stored for 14 days at 4 °C. O 2 levels in the packages of fresh-cut Iceberg lettuce decreased and CO 2 levels increased with increasing radiation dose, suggesting that irradiation increased respiration rates of lettuce. Tissue browning of irradiated cut lettuce was less severe than that of non-irradiated, probably due to the lower O 2 levels in the packages. However, samples irradiated at 3 and 4 kGy had lower maximum force and more severe sogginess than the non-irradiated control. In addition, ascorbic acid content of irradiated lettuce was 22–40% lower than the non-irradiated samples after 14 days of storage. The visual appearance of spinach was not affected by irradiation even at a dose of 4 kGy. Consumer acceptance suggested that more people would dislike and would not buy spinach that was treated at 3 and 4 kGy as compared to the non-irradiated sample. Overall, irradiation at doses of 1 and 2 kGy may be employed to enhance microbial safety of fresh-cut Iceberg lettuce and spinach while maintaining quality. - Highlights: ▶ Headspace composition in the modified atmosphere packages of cut lettuce was affected by irradiation. ▶ Fresh-cut lettuce in adapted atmosphere could tolerate 1 or 2 kGy rays without quality deterioration in look and texture. ▶ Lettuce irradiated at doses higher than 2 kGy developed sogginess. ▶ Irradiated spinach maintained a good appearance at doses of 3 and 4 kGy. ▶ Higher doses (3 and 4 kGy) of radiation decreased consumers' likingness and purchase intent of irradiated spinach.

  19. SU-E-T-762: Toward Volume-Based Independent Dose Verification as Secondary Check

    International Nuclear Information System (INIS)

    Tachibana, H; Tachibana, R

    2015-01-01

    Purpose: Lung SBRT plan has been shifted to volume prescription technique. However, point dose agreement is still verified using independent dose verification at the secondary check. The volume dose verification is more affected by inhomogeneous correction rather than point dose verification currently used as the check. A feasibility study for volume dose verification was conducted in lung SBRT plan. Methods: Six SBRT plans were collected in our institute. Two dose distributions with / without inhomogeneous correction were generated using Adaptive Convolve (AC) in Pinnacle3. Simple MU Analysis (SMU, Triangle Product, Ishikawa, JP) was used as the independent dose verification software program, in which a modified Clarkson-based algorithm was implemented and radiological path length was computed using CT images independently to the treatment planning system. The agreement in point dose and mean dose between the AC with / without the correction and the SMU were assessed. Results: In the point dose evaluation for the center of the GTV, the difference shows the systematic shift (4.5% ± 1.9 %) in comparison of the AC with the inhomogeneous correction, on the other hands, there was good agreement of 0.2 ± 0.9% between the SMU and the AC without the correction. In the volume evaluation, there were significant differences in mean dose for not only PTV (14.2 ± 5.1 %) but also GTV (8.0 ± 5.1 %) compared to the AC with the correction. Without the correction, the SMU showed good agreement for GTV (1.5 ± 0.9%) as well as PTV (0.9% ± 1.0%). Conclusion: The volume evaluation for secondary check may be possible in homogenous region. However, the volume including the inhomogeneous media would make larger discrepancy. Dose calculation algorithm for independent verification needs to be modified to take into account the inhomogeneous correction

  20. Dose reconstruction in deforming lung anatomy: Dose grid size effects and clinical implications

    International Nuclear Information System (INIS)

    Rosu, Mihaela; Chetty, Indrin J.; Balter, James M.; Kessler, Marc L.; McShan, Daniel L.; Ten Haken, Randall K.

    2005-01-01

    In this study we investigated the accumulation of dose to a deforming anatomy (such as lung) based on voxel tracking and by using time weighting factors derived from a breathing probability distribution function (p.d.f.). A mutual information registration scheme (using thin-plate spline warping) provided a transformation that allows the tracking of points between exhale and inhale treatment planning datasets (and/or intermediate state scans). The dose distributions were computed at the same resolution on each dataset using the Dose Planning Method (DPM) Monte Carlo code. Two accumulation/interpolation approaches were assessed. The first maps exhale dose grid points onto the inhale scan, estimates the doses at the 'tracked' locations by trilinear interpolation and scores the accumulated doses (via the p.d.f.) on the original exhale data set. In the second approach, the 'volume' associated with each exhale dose grid point (exhale dose voxel) is first subdivided into octants, the center of each octant is mapped to locations on the inhale dose grid and doses are estimated by trilinear interpolation. The octant doses are then averaged to form the inhale voxel dose and scored at the original exhale dose grid point location. Differences between the interpolation schemes are voxel size and tissue density dependent, but in general appear primarily only in regions with steep dose gradients (e.g., penumbra). Their magnitude (small regions of few percent differences) is less than the alterations in dose due to positional and shape changes from breathing in the first place. Thus, for sufficiently small dose grid point spacing, and relative to organ motion and deformation, differences due solely to the interpolation are unlikely to result in clinically significant differences to volume-based evaluation metrics such as mean lung dose (MLD) and tumor equivalent uniform dose (gEUD). The overall effects of deformation vary among patients. They depend on the tumor location, field