WorldWideScience

Sample records for cells radiation quality

  1. Influence of acute hypoxia and radiation quality on cell survival

    OpenAIRE

    Tinganelli, Walter; Ma, Ning-Yi; von Neubeck, Cläre; Maier, Andreas; Schicker, Corinna; Kraft-Weyrather, Wilma; Durante, Marco

    2013-01-01

    To measure the effect of acute oxygen depletion on cell survival for different types of radiation, experiments have been performed using Chinese hamster ovary (CHO) cells and RAT-1 rat prostate cancer cells. A special chamber has been developed to perform irradiations under different levels of oxygenation. The oxygen concentrations used were normoxia (air), hypoxia (94.5% N2, 5% CO2, 0.5% O2) and anoxia (95% N2, 5% CO2). Cells were exposed to X-rays and to C-, N- or O-ions with linear energy ...

  2. Influence of chronic hypoxia and radiation quality on cell survival

    International Nuclear Information System (INIS)

    The purpose of this study was to investigate the influence of chronic hypoxia and anoxia on cell survival after low- and high-linear energy transfer (LET) radiation, Chinese hamster ovary K1 (CHO-K1) cells were kept for 24 h under chronic hypoxia (94.5% N2; 5% CO2; 0.5% O2) or chronic anoxia (95% N2; 5% CO2). Irradiation was performed using 250 kVp X-rays or carbon ions with a dose average LET of 100 keV/μm either directly under the chronic oxygenation states, or at different time points after reoxygenation. Moreover, the cell cycle distribution for cells irradiated under different chronic oxic states was measured over 24 h during reoxygenation. The measurements showed a fairly uniform cell cycle distribution under chronic hypoxia, similar to normoxic conditions. Chronic anoxia induced a block in G1 and a strong reduction of S-phase cells. A distribution similar to normoxic conditions was reached after 12 h of reoxygenation. CHO cells had a similar survival under both acute and chronic hypoxia. In contrast, survival after irradiation under chronic anoxia was slightly reduced compared to that under acute anoxia. We conclude that, in hamster cells, chronic anoxia is less effective than acute anoxia in inducing radioresistance for both X-rays and carbon ions, whereas in hypoxia, acute and chronic exposures have a similar impact on cell killing. (author)

  3. Influence of acute hypoxia and radiation quality on cell survival

    International Nuclear Information System (INIS)

    The purpose of this study was to measure the effect of acute oxygen depletion on cell survival for different types of radiation, experiments have been performed using Chinese hamster ovary (CHO) cells and R-3327-AT1 (RAT-1) rat prostate cancer cells. A special chamber has been developed to perform irradiations under different levels of oxygenation. The oxygen concentrations used were normoxia (air), hypoxia (94.5% N2, 5% CO2, 0.5% O2) and anoxia (95% N2, 5% CO2). Cells were exposed to X-rays and to C-, N- or O-ions with linear energy transfer (LET) values ranging from 100-160 keV/μm. The oxygen enhancement ratio (OER) and relative biological effectiveness (RBE) values have been calculated from the measured clonogenic survival curves. For both cell lines, the X-ray OER depended on the survival level. For particle irradiation, OER was not dependent on the survival level but decreased with increasing LET. The RBE of CHO cells under oxic conditions reached a plateau for LET values above 100 keV/μm, while it was still increasing under anoxia. In conclusion, the results demonstrated that our chamber could be used to measure radiosensitivity under intermediate hypoxia. Measurements suggest that ions heavier than carbon could be of additional advantage in the irradiation, especially of radioresistant hypoxic tumor regions. (author)

  4. Detailed probabilistic modelling of cell inactivation by ionizing radiations of different qualities: The model and its applications

    Energy Technology Data Exchange (ETDEWEB)

    Kundrat, Pavel, E-mail: Pavel.Kundrat@fzu.cz

    2009-03-15

    The probabilistic two-stage model of cell killing by ionizing radiation enables to represent both damage induction by radiation and its repair by the cell. The model properties and applications as well as possible interpretation of the underlying damage classification are discussed. Analyses of published survival data for V79 hamster cells irradiated by protons and He, C, O, and Ne ions are reported, quantifying the variations in radiation quality with increasing charge and linear energy transfer of the ions.

  5. Glioblastoma stem cells: radiobiological response to ionising radiations of different qualities

    International Nuclear Information System (INIS)

    Glioblastoma multiform (GBM) is the most common and malignant primary brain tumour, with very poor prognosis. The high recurrence rate and failure of conventional treatments are expected to be related to the presence of radio-resistant cancer stem cells (CSCs) inside the tumour mass. CSCs can both self-renew and differentiate into the heterogeneous lineages of cancer cells. Recent evidence showed a higher effectiveness of C-ions and protons in inactivating CSCs, suggesting a potential advantage of Hadrontherapy compared with conventional radiotherapy for GBM treatment. To investigate the mechanisms involved in the molecular and cellular responses of CSCs to ionising radiations, two GBM stem cell (GSC) lines, named lines 1 and 83, which were derived from patients with different clinical outcomes and having different metabolic profiles (as shown by NMR spectroscopy), were irradiated with 137Cs photons and with protons or C-ions of 62 MeV u-1 in the dose range of 5- 40 Gy. The biological effects investigated were: cell death, cell cycle progression, and DNA damage induction and repair. Preliminary results show a different response to ionising radiation between the two GSC lines for the different end points investigated. Further experiments are in progress to consolidate the data and to get more insights on the influence of radiation quality. (authors)

  6. Glioblastoma stem cells: radiobiological response to ionising radiations of different qualities.

    Science.gov (United States)

    Pecchia, I; Dini, V; Ricci-Vitiani, L; Biffoni, M; Balduzzi, M; Fratini, E; Belli, M; Campa, A; Esposito, G; Cirrone, G; Romano, F; Stancampiano, C; Pelacchi, F; Pallini, R; Tabocchini, M A

    2015-09-01

    Glioblastoma multiforme (GBM) is the most common and malignant primary brain tumour, with very poor prognosis. The high recurrence rate and failure of conventional treatments are expected to be related to the presence of radio-resistant cancer stem cells (CSCs) inside the tumour mass. CSCs can both self-renew and differentiate into the heterogeneous lineages of cancer cells. Recent evidence showed a higher effectiveness of C-ions and protons in inactivating CSCs, suggesting a potential advantage of Hadrontherapy compared with conventional radiotherapy for GBM treatment. To investigate the mechanisms involved in the molecular and cellular responses of CSCs to ionising radiations, two GBM stem cell (GSC) lines, named lines 1 and 83, which were derived from patients with different clinical outcomes and having different metabolic profiles (as shown by NMR spectroscopy), were irradiated with (137)Cs photons and with protons or C-ions of 62 MeV u(-1) in the dose range of 5-40 Gy. The biological effects investigated were: cell death, cell cycle progression, and DNA damage induction and repair. Preliminary results show a different response to ionising radiation between the two GSC lines for the different end points investigated. Further experiments are in progress to consolidate the data and to get more insights on the influence of radiation quality. PMID:25969527

  7. Effects of the ionizing radiations, freezing and thawing duration on chicken liver cells quality

    Science.gov (United States)

    Duarte, R. C.; Araújo, M. M.; Salum, D. C.; Marchioni, E.; Villavicencio, A. L. C. H.

    2009-07-01

    All food storage processes modify the food. Irradiation reduces and could stop cell division, avoid infestation, reduce contamination and delay food decomposition. The cold chain is a succession of steps which maintains the food at low temperature. Defrosted food shall never be frozen again, the best way being to consume it quickly then avoiding multiplication and acceleration of microbial growth, which causes decay and nutrients damage. The Comet Assay indicates DNA damage and can then be used to control the overall quality of the food and in a certain extent to evaluate the damage caused by irradiation and storage on liver chicken cells. In this work, different thawing temperatures and radiation doses were checked to establish a "DNA damage index" by using the Comet Assay. Samples were irradiated in a 60Co irradiator with 1.5, 3.0 and 4.5 kGy radiation doses. Our results showed that no intact cells were detected in frozen samples: however, irradiated liver samples in natura showed some intact cells depending on the applied radiation doses.

  8. On the quality of mutations in mammalian cells induced by high LET radiations

    Science.gov (United States)

    Baumstark-Khan, Christa; Rosendahl, Ilja M.; Rink, Hermann

    The deleterious effects of accelerated heavy ions as component of the space radiation environment on living cells are of increasing importance for long duration human space flight activities. The most important aspect of such densely ionizing particle radiation is attributed to the type and quality of biological damage induced by them. This issue is addressed by investigating cell inactivation and mutation induction at the Hprt locus (coding for hypoxanthine-guanine-phosphoribosyl-transferase) of cultured V79 Chinese hamster cells exposed to densely ionizing radiation (accelerated heavy ions with different LETs from oxygen to gold, specific energies ranging from 1.9 to 69.7 MeV/u, corresponding LET values range from 62 to 13,223 keV/μm) and to sparsely ionizing radiation (200 kV X-rays). 30 spontaneous, 40 X-ray induced and 196 heavy ion induced 6-thioguanine resistant Hprt mutant colonies were characterized by Southern technique using the restriction enzymes EcoRI, PstI and BglII and a full length Hprt cDNA probe isolated from the plasmid pHPT12. Restriction patterns of the spontaneous Hprt mutants were indistinguishable from the wild type pattern, as these mutants probably contain only small deletions or even point mutations in the Hprt locus. In contrast, the overall spectrum of heavy ion induced mutations revealed a majority of partial or total deletions of the Hprt gene. With constant particle fluence (3 × 10 6 particles/cm 2) the quality of heavy ion induced mutations in the Hprt locus depends on physical parameters of the beam (atomic number, specific energy, LET). This finding suggests a relationship between the type of DNA damage and track structure. The fraction of mutants with severe deletions in the Hprt locus after exposure to oxygen ions increases from 65% at 60 keV/μm up to a maximum (100%) at 300 keV/μm and declines with higher LET values to 75% at 750 keV/μm. With heavier ions (Ca- and Au-ions) and even higher LET-values this mutant fraction

  9. The indirect effect of radiation reduces the repair fidelity of NHEJ as verified in repair deficient CHO cell lines exposed to different radiation qualities and potassium bromate

    Energy Technology Data Exchange (ETDEWEB)

    Bajinskis, Ainars, E-mail: ainars.bajinskis@gmt.su.se [Centre for Radiation Protection Research, Department of Genetics, Microbiology and Toxicology, Stockholm University, S-10691 Stockholm (Sweden); Olsson, Gunilla; Harms-Ringdahl, Mats [Centre for Radiation Protection Research, Department of Genetics, Microbiology and Toxicology, Stockholm University, S-10691 Stockholm (Sweden)

    2012-03-01

    The complexity of DNA lesions induced by ionizing radiation is mainly dependent on radiation quality, where the indirect action of radiation may contribute to different extent depending on the type of radiation under study. The effect of indirect action of radiation can be investigated by using agents that induce oxidative DNA damage or by applying free radical scavengers. The aim of this study was to investigate the role of the indirect effect of radiation for the repair fidelity of non-homologous end-joining (NHEJ), homologous recombination repair (HRR) and base excision repair (BER) when DNA damage of different complexity was induced by gamma radiation, alpha particles or from base damages (8-oxo-dG) induced by potassium bromate (KBrO{sub 3}). CHO cells lines deficient in XRCC3 (HRR) irs1SF, XRCC7 (NHEJ) V3-3 and XRCC1 (BER) EM9 were irradiated in the absence or presence of the free radical scavenger dimethyl sulfoxide (DMSO). The endpoints investigated included rate of cell proliferation by the DRAG assay, clonogenic cell survival and the level of primary DNA damage by the comet assay. The results revealed that the indirect effect of low-LET radiation significantly reduced the repair fidelity of both NHEJ and HRR pathways. For high-LET radiation the indirect effect of radiation also significantly reduced the repair fidelity for the repair deficient cell lines. The results suggest further that the repair fidelity of the error prone NHEJ repair pathway is more impaired by the indirect effect of high-LET radiation relative to the other repair pathways studied. The response to bromate observed for the two DSB repair deficient cell lines strongly support earlier studies that bromate induces complex DNA damages. The significantly reduced repair fidelity of irs1SF and V3-3 suggests that NHEJ as well as HRR are needed for the repair, and that complex DSBs are formed after bromate exposure.

  10. Influence of radiation therapy quality control on survival, response and sites of relapse in oat cell carcinoma of the lung

    International Nuclear Information System (INIS)

    Two hundred and ninety-eight patients with limited (confined to chest and supraclavicular area, encompassable by a single radiation portal) small cell carcinoma of the lung were entered on Southwest Oncology Group Protocol 7628. Patients were treated with multi-agent chemotherapy and radiation therapy with or without BCG. Radiation therapy quality control analysis, including dosimetric reconstruction and port film review was introduced after the protocol was activated and was retrospectively applied. Patients who were considered major protocol variations had statistically worse survival (40 weeks versus 60 weeks; P = .002), a lesser improvement in response rate after induction chemotherapy (27 versus 48%; P = .05) and a higher chest failure rate (77 versus 55%; P = .047) than evaluable patients. Five patients relapsed in the brain, all associated with chest failure. Quality control is essential in cooperative group studies

  11. Chromosomal Aberrations in DNA Repair Defective Cell Lines: Comparisons of Dose Rate and Radiation Quality

    Science.gov (United States)

    George, K. A.; Hada, M.; Patel, Z.; Huff, J.; Pluth, J. M.; Cucinotta, F. A.

    2009-01-01

    Chromosome aberration yields were assessed in DNA double-strand break repair (DSB) deficient cells after acute doses of gamma-rays or high-LET iron nuclei, or low dose-rate (0.018 Gy/hr) gamma-rays. We studied several cell lines including fibroblasts deficient in ATM (product of the gene that is mutated in ataxia telangiectasia patients) or NBS (product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase, DNA-PK activity. Chromosomes were analyzed using the fluorescence in-situ hybridization (FISH) chromosome painting method in cells at the first division post-irradiation and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma radiation induced higher yields of both simple and complex exchanges in the DSB repair defective cells than in the normal cells. The quadratic dose-response terms for both chromosome exchange types were significantly higher for the ATM and NBS defective lines than for normal fibroblasts. However, the linear dose-response term was significantly higher only for simple exchanges in the NBS cells. Large increases in the quadratic dose response terms indicate the important roles of ATM and NBS in chromatin modifications that facilitate correct DSB repair and minimize aberration formation. Differences in the response of AT and NBS deficient cells at lower doses suggests important questions about the applicability of observations of radiation sensitivity at high dose to low dose exposures. For all iron nuclei irradiated cells, regression models preferred purely linear and quadratic dose responses for simple and complex exchanges, respectively. All the DNA repair defective cell lines had lower Relative biological effectiveness (RBE) values than normal cells, the lowest being for the DNA-PK-deficient cells, which was near unity. To further

  12. Quality of life in patients receiving curative radiation therapy for non-small cell lung cancer

    International Nuclear Information System (INIS)

    Purpose/Objective: The purpose of this study was to determine if perceptions of quality of life (QOL) change in patients with non-small cell lung cancer (NSCLC) receiving curative radiation therapy (XRT) alone or in combination with other treatment modalities. Materials and Methods: The Functional Assessment of Cancer Therapy-Lung (FACT-L) (Cella, 1994), a 37-item Likert-type questionnaire that measures QOL in lung cancer patients, was used to assess QOL in NSCLC patients receiving curative XRT. A descriptive, longitudinal design with repeated measures was utilized for this study, and subjects were selected using a consecutive sampling technique. Subjects completed the FACT-L prior to beginning XRT, during the fourth week of XRT, and one and four months after completion of XRT. Results: The sample included 23 patients with Stage IIIA (n=8, 35%) or IIIB (n=15, 65%) NSCLC. Treatment regimens included XRT alone (n=1, 4%), postoperative XRT (n=9, 39%), postoperative XRT with concurrent chemotherapy (n=1, 4%), induction chemotherapy followed by XRT with concurrent chemotherapy (n=4, 17%), and XRT with concurrent chemotherapy (n=8, 35%). Internal consistency reliability was adequate for the FACT-L (r=.85-.96) over the four measures. The research question, do perceptions of QOL change in NSCLC patients receiving XRT, was examined using a multivariate approach to analysis of variance (ANOVA) for repeated measures. QOL was significantly less during XRT than prior to XRT (p=.006, power=.83) and was significantly greater one month after XRT than prior to XRT (p=.01, power=.77) or during XRT (p≤.0005, power=.99). There was no significant difference between QOL at one and four months after completion of XRT. No correlation was found between QOL and treatment regimen. Conclusions: These preliminary findings suggest that there is a significant decrease in QOL in NSCLC patients during treatment with XRT, but QOL is significantly greater following XRT than it was prior to or

  13. Mutant quantity and quality in mammalian cells (AL) exposed to cesium-137 gamma radiation: Effect of caffeine

    International Nuclear Information System (INIS)

    We examined the effect of caffeine (1,3,7-trimethylxanthine) on the quantity and quality of mutations in cultured mammalian AL human-hamster hybrid cells exposed to 137Cs γ radiation. At a dose (1.5 mg/ml for 16 h) that reduced the plating efficiency (PE) by 20%, caffeine was not itself a significant mutagen, but it increased by approximately twofold the slope of the dose-response curve for induction of S1- mutants by 137Cs γ radiation. Molecular analysis of 235 S1- mutants using a series of DNA probes mapped to the human chromosome 11 in the AL hybrid cells revealed that 73 to 85% of the mutations in unexposed cells and in cells treated with caffeine alone, 137Cs γ rays alone or 137Cs γ rays plus caffeine were large deletions involving millions of base pairs of DNA. Most of these deletions were contiguous with the region of the MIC1 gene at 11p13 that encodes the S1 cell surface antigen. In other mutants that had suffered multiple marker loss, the deletions were intermittent along chromosome 11. These open-quotes complexclose quotes mutations were rare for 137Cs γ irradiation (1/63 = 1.5%) but relatively prevalent (23-50%) for other exposure conditions. Thus caffeine appears to alter both the quantity and quality of mutations induced by 137Cs γ irradiation. 62 refs., 3 figs., 3 tabs

  14. Induction of DNA double-strand breaks by ionizing radiation of different quality and their relevance for cell inactivation

    International Nuclear Information System (INIS)

    By investigation of the production of DNA strand breaks and of DNA release from the nuclear membrane complex in Chinese hamster cells using different radiation qualities from 1 to 360 keV/μm, partly also under hypoxic conditions, and by relating the results to the induction of chromosome aberrations and to cell inactivation it has become possible to find connections between the induction of molecular lesions and the expression of this damage on the cellular level. From the studies follows that DNA pieces are cut off from the nuclear membrane complex by DNA double-strand breaks (DSB). The share and size of the released pieces depends on radiation dose and quality as well as on the oxygen conditions. The lesions can partly be repaired. In connection with the DSB rates the results of the DNA release studies led to the conclusion that the DNA in the cells must be organized in superstructure units (MASSUs) with a DNA mass of about 2 x 109 g/mol, which are associated to the nuclear membrane in attachment points. The numerical relations show that for a 37% survival probability about 90 DSB per genome are required with sparsely ionizing radiation; this number declines to about 40 by use of more densely ionizing radiation up to 150 keV/μm, and increases again with further rise of the ionization density. Hence, for cell inactivation not simply a certain number of DSB per cell is required but rather seems their cooperation within a small structure section of the DNA to be relevant. These critical structures are with high probability the MASSUs. An irrepairable release of DNA from such a structure unit can bring about a chromosome break detectable in the metaphase and finally lead to cell inactivation. DSB turned out to be the essential lethal events in bacteria as well. The relatively small differences to the eukaryotic cells in the position of the maximum of radiation sensitivity on the LET scale and in the lesion sensitivity towards DSB let suggest that a common critical

  15. Quality Indicators in Radiation Oncology

    International Nuclear Information System (INIS)

    Oncologic specialty societies and multidisciplinary collaborative groups have dedicated considerable effort to developing evidence-based quality indicators (QIs) to facilitate quality improvement, accreditation, benchmarking, reimbursement, maintenance of certification, and regulatory reporting. In particular, the field of radiation oncology has a long history of organized quality assessment efforts and continues to work toward developing consensus quality standards in the face of continually evolving technologies and standards of care. This report provides a comprehensive review of the current state of quality assessment in radiation oncology. Specifically, this report highlights implications of the healthcare quality movement for radiation oncology and reviews existing efforts to define and measure quality in the field, with focus on dimensions of quality specific to radiation oncology within the “big picture” of oncologic quality assessment efforts

  16. Production of DNA strand breaks by ionizing radiation of different quality and their consequences for cell inactivation

    International Nuclear Information System (INIS)

    The production of single- and double-strand breaks (DSB) in the DNA of Chinese hamster cells (V 79) was studied by use of 11 radiation qualities, with some also under hypoxic conditions. The aim was to find relations between the induction of lesions on the molecular level and the expression of this damage on the cellular level. The results suggest that release of DNA from the nuclear-membrane complex, induction of chromosome breaks, and cell inactivation are triggered by DSB. However, not simply a certain number of DSB in the DNA of the nucleus, but their cooperation within a small structural section of DNA is required for cell inactivation. Such sections may be the membrane-associated superstructure units. DSB produced under hypoxic conditions show a greater effectiveness than those produced under oxic conditions. The investigations with eukaryotic cells and bacteria suggest that not the entire DNA of all organisms but a structural unit common to them represents the critical target for radiation action. (author)

  17. Radiation protection and quality management

    International Nuclear Information System (INIS)

    The book contains the following contributions: Radiation protection: an aspect of the governmental assignment to guarantee and regulate the public safety and law and order; the regulation amendment concerning X radiation and the new radiation protection ordinance; biological radiation effects; dosimetry; modern diagnostic radiology; the vindicatory indication; experiences of applied radiation protection in X-ray diagnostics: multislice computer tomography, X-ray examination and angiography; networking imaging; vindicatory indication in radiotherapy: for malign diseases and for benign diseases; medical appointments; quality management in health care; quality management in practice and clinics; personal management in health care - a challenging assignment under the aspects of resource control and quality. Appendices: Regulation concerning X radiation protection and remarks; regulation concerning ionising radiation protection: excerpts and remarks

  18. Radiation measurements and quality control

    International Nuclear Information System (INIS)

    The association between radiation measurements and quality control is established for radiation sterilization of medical products and food irradiation. Good quality control implies accurate radiation dosimetry and a discussion of the factors which can affect the accuracy of in-plant dosimetry is presented. It is argued that if systematic errors are to be avoided in in-plant dosimetry the plant operators will have to spend more time and effort in developing the skills associated with the accurate use of radiation dosemeter systems. The aims and merits of an international intercomparison programme recently set up by the IAEA are discussed. The benefits of accurate in-plant dosimetry for the operator, approving authority and purchaser are balanced against the extra dosimetric efforts required for good quality control. (author)

  19. Hyper-radiosensitivity and induced radioresistance and bystander effects in rodent and human cells as a function of radiation quality

    International Nuclear Information System (INIS)

    In the past two decades, a body of experimental evidences in vitro has shown the presence of a plethora of phenomena occurring after low-dose irradiation [including hypersensitivity and induced radioresistance (IRR), adaptive response, bystander effect (BE) and genomic instability], which might imply a non-linear behaviour of cancer risk curves in the low-dose region and question the validity of the linear no-threshold model for cancer risk assessment in such a dose region. In this framework, a systematic investigation have been undertaken on non-linear effects at low doses as a function of different radiation quality and cellular radiosensitivity and in terms of different biological end points. The present article reports the recent results on hyper-radiosensitivity and IRR and BE phenomena, in terms of clonogenic survival in V79 Chinese hamster cells and T98G human glioblastoma cells irradiated with protons and carbon ions with different energy, as a function of dose (and fluence). (authors)

  20. Efficacy of radiation countermeasures depends on radiation quality.

    Science.gov (United States)

    Cary, Lynnette H; Ngudiankama, Barbara F; Salber, Rudolph E; Ledney, G David; Whitnall, Mark H

    2012-05-01

    The detonation of a nuclear weapon or a nuclear accident represent possible events with significant exposure to mixed neutron/γ-radiation fields. Although radiation countermeasures generally have been studied in subjects exposed to pure photons (γ or X rays), the mechanisms of injury of these low linear energy transfer (LET) radiations are different from those of high-LET radiation such as neutrons, and these differences may affect countermeasure efficacy. We compared 30-day survival in mice after varying doses of pure γ and mixed neutron/γ (mixed field) radiation (MF, Dn/Dt = 0.65), and also examined peripheral blood cells, bone marrow cell reconstitution, and cytokine expression. Mixed-field-irradiated mice displayed prolonged defects in T-cell populations compared to mice irradiated with pure γ photons. In mouse survival assays, the growth factor granulocyte colony-stimulating factor (G-CSF) was effective as a (post-irradiation) mitigator against both γ-photons and mixed-field radiation, while the thrombopoietin (TPO) mimetic ALXN4100TPO was effective only against γ irradiation. The results indicate that radiation countermeasures should be tested against radiation qualities appropriate for specific scenarios before inclusion in response plans. PMID:22468705

  1. Cellular and molecular studies on radiation quality

    International Nuclear Information System (INIS)

    The influence of radiation quality is measured for different biological endpoints like the induction of single and double strand breaks, chromosome aberrations, and cell cycle effects. From the analysis of the chromosome aberrations, it is expected to gain more insight the mechanism of the damage induction and interaction. Strand break induction of both single and double strand breaks, is measured as function of the chemical environment for extra- and intracellular DNA in order to estimate the influence of radiation quality. Studies of the perturbation of cell cycle progression are important for the interpretation of the chromosome aberration measurements, and they can be also used at a fast monitor of radiation damage. Objectives and results of the four contributions to the project for the reporting period are presented. (R.P.) 7 refs

  2. Impact of partial versus whole breast radiation therapy on fatigue, perceived stress, quality of life and natural killer cell activity in women with breast cancer

    Directory of Open Access Journals (Sweden)

    Albuquerque Kevin

    2012-06-01

    Full Text Available Abstract Introduction This pilot study used a prospective longitudinal design to compare the effect of adjuvant whole breast radiation therapy (WBRT versus partial breast radiation therapy (PBRT on fatigue, perceived stress, quality of life and natural killer cell activity (NKCA in women receiving radiation after breast cancer surgery. Methods Women (N = 30 with early-stage breast cancer received either PBRT, Mammosite brachytherapy at dose of 34 Gy 10 fractions/5 days, (N = 15 or WBRT, 3-D conformal techniques at dose of 50 Gy +10 Gy Boost/30 fractions, (N = 15. Treatment was determined by the attending oncologist after discussion with the patient and the choice was based on tumor stage and clinical need. Women were assessed prior to initiation of radiation therapy and twice after completion of radiation therapy. At each assessment, blood was obtained for determination of NKCA and the following instruments were administered: Perceived Stress Scale (PSS, Functional Assessment of Cancer Therapy-Fatigue (FACT-F, and Functional Assessment of Cancer Therapy-General (FACT-G. Hierarchical linear modeling (HLM was used to evaluate group differences in initial outcomes and change in outcomes over time. Results Fatigue (FACT-F levels, which were similar prior to radiation therapy, demonstrated a significant difference in trajectory. Women who received PBRT reported progressively lower fatigue; conversely fatigue worsened over time for women who received WBRT. No difference in perceived stress was observed between women who received PBRT or WBRT. Both groups of women reported similar levels of quality of life (FACT-G prior to initiation of radiation therapy. However, HLM analysis revealed significant group differences in the trajectory of quality of life, such that women receiving PBRT exhibited a linear increase in quality of life over time after completion of radiation therapy; whereas women receiving WBRT showed a decreasing

  3. Impact of partial versus whole breast radiation therapy on fatigue, perceived stress, quality of life and natural killer cell activity in women with breast cancer

    International Nuclear Information System (INIS)

    This pilot study used a prospective longitudinal design to compare the effect of adjuvant whole breast radiation therapy (WBRT) versus partial breast radiation therapy (PBRT) on fatigue, perceived stress, quality of life and natural killer cell activity (NKCA) in women receiving radiation after breast cancer surgery. Women (N = 30) with early-stage breast cancer received either PBRT, Mammosite brachytherapy at dose of 34 Gy 10 fractions/5 days, (N = 15) or WBRT, 3-D conformal techniques at dose of 50 Gy +10 Gy Boost/30 fractions, (N = 15). Treatment was determined by the attending oncologist after discussion with the patient and the choice was based on tumor stage and clinical need. Women were assessed prior to initiation of radiation therapy and twice after completion of radiation therapy. At each assessment, blood was obtained for determination of NKCA and the following instruments were administered: Perceived Stress Scale (PSS), Functional Assessment of Cancer Therapy-Fatigue (FACT-F), and Functional Assessment of Cancer Therapy-General (FACT-G). Hierarchical linear modeling (HLM) was used to evaluate group differences in initial outcomes and change in outcomes over time. Fatigue (FACT-F) levels, which were similar prior to radiation therapy, demonstrated a significant difference in trajectory. Women who received PBRT reported progressively lower fatigue; conversely fatigue worsened over time for women who received WBRT. No difference in perceived stress was observed between women who received PBRT or WBRT. Both groups of women reported similar levels of quality of life (FACT-G) prior to initiation of radiation therapy. However, HLM analysis revealed significant group differences in the trajectory of quality of life, such that women receiving PBRT exhibited a linear increase in quality of life over time after completion of radiation therapy; whereas women receiving WBRT showed a decreasing trajectory. NKCA was also similar between therapy groups but additional

  4. Radiation measurements and quality control

    International Nuclear Information System (INIS)

    Accurate measurements are essential to research leading to a successful radiation process and to the commissioning of the process and the facility. On the other hand, once the process is in production, the importance to quality control of measuring radiation quantities (i.e., absorbed dose, dose rate, dose distribution) rather than various other parameters of the process (i.e. conveyor speed, dwell time, radiation field characteristics, product dimensions) is not clearly established. When the safety of the product is determined by the magnitude of the administered dose, as in radiation sterilization, waste control, or food preservation, accuracy and precision of the measurement of the effective dose are vital. Since physical dose measurements are usually simpler, more reliable and reproducible than biological testing of the product, there is a trend toward using standardized dosimetry for quality control of some processes. In many industrial products, however, such as vulcanized rubber, textiles, plastics, coatings, films, wire and cable, the effective dose can be controlled satisfactorily by controlling process variables or by product testing itself. In the measurement of radiation dose profiles by dosimetry, it is necessary to have suitable dose meter calibrations, to account for sources of error and imprecision, and to use correct statistical procedures in specifying dwell times or conveyor speeds and source and product parameters to achieve minimum and maximum doses within specifications. (author)

  5. Solar cell radiation handbook

    Science.gov (United States)

    Tada, H. Y.; Carter, J. R., Jr.; Anspaugh, B. E.; Downing, R. G.

    1982-01-01

    The handbook to predict the degradation of solar cell electrical performance in any given space radiation environment is presented. Solar cell theory, cell manufacturing and how they are modeled mathematically are described. The interaction of energetic charged particles radiation with solar cells is discussed and the concept of 1 MeV equivalent electron fluence is introduced. The space radiation environment is described and methods of calculating equivalent fluences for the space environment are developed. A computer program was written to perform the equivalent fluence calculations and a FORTRAN listing of the program is included. Data detailing the degradation of solar cell electrical parameters as a function of 1 MeV electron fluence are presented.

  6. Quality of Life (QOL) Analysis of a Randomized Radiation Dose Escalation Non-Small Cell Lung Cancer (NSCLC) Study: Radiation Therapy Oncology Group (RTOG) Trial 0617

    Science.gov (United States)

    Movsas, Benjamin; Hu, Chen; Sloan, Jeffrey; Bradley, Jeffrey; Komaki, Ritsuko; Masters, Gregory; Kavadi, Vivek; Narayan, Samir; Michalski, Jeff; Johnson, Douglas W.; Koprowski, Christopher; Curran, Walter J.; Garces, Yolanda I.; Gaur, Rakesh; Wynn, Raymond B.; Schallenkamp, John; Gelblum, Daphna Y.; MacRae, Robert M; Paulus, Rebecca; Choy, Hak

    2015-01-01

    Importance A recent randomized radiation dose escalation trial in unresectable stage III NSCLC showed a lower survival in the high-dose arm (74Gy vs. 60Gy) with concurrent chemotherapy. Quality of life (QOL), an important secondary endpoint, is presented here. Objective The primary QOL hypothesis predicted a clinically meaningful decline (CMD) in QOL via the Functional Assessment of Cancer Therapy-Lung Cancer Subscale (FACT-LCS) in the high-dose RT-arm at 3 months. Design RTOG 0617 was a randomized phase III study (conducted from Nov 2007 to Nov 2011) in stage III NSCLC using a 2×2 factorial design and stratified by histology, PET staging, performance status and radiation technique (3D-conformal RT [3DCRT] vs. intensity-modulated radiation [IMRT]). Setting 185 institutions in the USA and Canada. Participants Of 424 eligible stage III NSCLC patients randomized, 360 (85%) consented to QOL, of whom 313 (88%) completed baseline QOL assessments. Intervention for Clinical Trials 74Gy vs. 60Gy with concurrent and consolidation carboplatin/paclitaxel +/− cetuximab. Main Outcomes and Measures QOL was collected prospectively via FACT-Trial Outcome Index (FACT-TOI), equaling Physical-Well-Being (PWB) + Functional-Well-Being (FWB) + Lung Cancer Subscale (LCS). Data are presented at baseline & 3 and 12 months via minimal clinically meaningful changes of >=2 points for PWB, FWB or LCS or >=5 points for TOI. Results Patient demographics and baseline QOL scores were comparable between the 74Gy and 60Gy arms. Two-hundred-nineteen (72%) of living patients who completed QOL at baseline did so at 3 months and 137 (57%) of living patients did so at 12 months. Significantly more patients on 74Gy arm had clinically meaningful decline in FACT-LCS at 3 months than on the 60Gy arm (45% vs. 30%, p=0.02). At 12 months, fewer patients who received IMRT (vs 3DCRT) had clinically meaningful decline in FACT-LCS (21% vs 46%, p=0.003). Baseline FACT-TOI was associated with overall survival in

  7. A Biodosimeter for Multiparametric Determination of Radiation Dose, Radiation Quality, and Radiation Risk

    Science.gov (United States)

    Richmond, Robert; Cruz, Angela; Jansen, Heather; Bors, Karen

    2003-01-01

    Predicting risk of human cancer following exposure of an individual or a population to ionizing radiation is challenging. To an approximation, this is because uncertainties of uniform absorption of dose and the uniform processing of dose-related damage at the cellular level within a complex set of biological variables degrade the confidence of predicting the delayed expression of cancer as a relatively rare event. Cellular biodosimeters that simultaneously report: 1) the quantity of absorbed dose after exposure to ionizing radiation, 2) the quality of radiation delivering that dose, and 3) the risk of developing cancer by the cells absorbing that dose would therefore be useful. An approach to such a multiparametric biodosimeter will be reported. This is the demonstration of a dose responsive field effect of enhanced expression of keratin 18 (K18) in cultures of human mammary epithelial cells irradiated with cesium-1 37 gamma-rays. Dose response of enhanced K18 expression was experimentally extended over a range of 30 to 90 cGy for cells evaluated at mid-log phase. K18 has been reported to be a marker for tumor staging and for apoptosis, and thereby serves as an example of a potential marker for cancer risk, where the reality of such predictive value would require additional experimental development. Since observed radiogenic increase in expression of K18 is a field effect, ie., chronically present in all cells of the irradiated population, it may be hypothesized that K18 expression in specific cells absorbing particulate irradiation, such as the high-LET-producing atomic nuclei of space radiation, will report on both the single-cell distributions of those particles amongst cells within the exposed population, and that the relatively high dose per cell delivered by densely ionizing tracks of those intersecting particles will lead to cell-specific high-expression levels of K18, thereby providing analytical end points that may be used to resolve both the quantity and

  8. A quality-adjusted reanalysis of a Phase III trial comparing once-daily thoracic radiation vs. twice-daily thoracic radiation in patients with limited-stage small-cell lung cancer

    International Nuclear Information System (INIS)

    Purpose: We undertook an analysis of quality-adjusted survival using the Q-TWiST (Quality Time Without Symptoms or Toxicity) methodology and developed a new graphic representation called a quality-adjusted life-years plot, which presents a complete and concise Q-TWiST analysis on a single plot. Methods and Materials: The Q-TWiST plot incorporates the time without symptoms or toxicity and several combinations of utility coefficients for toxicity and relapse days into the same plot. In addition, the plot includes threshold lines, to judge whether a particular combination of utility coefficients reaches a significance level. Results: The differential in toxicity incidence and severity between the two thoracic radiation treatment arms was inconsequential. Sensitivity analyses were run using Q-TWiST plots. For all combinations of the various toxicity definitions and utility coefficients, the median Q-TWiST was greater for the once-daily thoracic radiation treatment arm than for the twice-daily treatment arm, without achieved significance. Conclusion: This work refines the results previously reported for this Phase III clinical trial in patients with limited-stage small-cell cancer, and there was no significant difference in survival after adjusting for toxicity and progression. Furthermore, the new methods developed for this trial allow for a more detailed and parsimonious presentation of survival and toxicity data for all oncology clinical trials

  9. Quality assurance in radiation measurement

    International Nuclear Information System (INIS)

    The achievement of traceability to recognize measurement standards for ionizing radiation posses special requirements. Methods of transferring reference standard to the working situation are devised through calibration and appropriate traceability, which optimize the accuracy attainable with the method of dose determination in routine use. Appropriate procedures are developed by the SSDL-MINT to establish accurate dose measurement in wide range of radiation fields such as in medicine, agriculture and industrial application. The status of work including effort towards ISO 9000 certification of SSDL dosimetry services will be summarized. (Author)

  10. Mammography Radiation Dose and Image Quality

    International Nuclear Information System (INIS)

    The early detection of breast cancer is technologically very challenging for radiography. At present screen-film mammography is the favoured method for early detection of breast cancer. In the United States, screening is under way and a large number of asymptomatic women are being exposed to radiation for the purpose of detecting early occult cancer. The prognosis for this disease is greatly improved if the cancer can be found before it reaches the size of 1 cm. Because of the widespread use of this imaging technology, much attention has been paid to its optimisation in terms of patient radiation dose, required image quality and quality control. Mammography in the USA is regulated by the Federal Government through mandatory facility certification including annual inspections and a specified quality control programme. However, there is still a wide range of radiation dose delivered to achieve a given film optical density and level of image quality. (author)

  11. Influence of radiation quality on the expression of chromosomal damage

    International Nuclear Information System (INIS)

    The amount of chromosomal damage induced in synchronous V79 cells by either 250 kV X-rays or 4.6 MeV/u Ar ions (LET: 1850 keV/μm) was determined at five successive sampling times. The experiments show that the time course of the appearance of damaged cells is strongly influenced by radiation-induced cell cycle perturbations and mitotic delay and depends on radiation quality and dose. The yield of chromosomal damage was found to increase with sampling time, but this increase was more pronounced for Ar ions. Because of the observed differences in the yield time profiles induced by sparsely and densely ionizing radiation the contribution of each sample to the overall damage was considered, i.e. the total (time integrated) amount of damage was determined. The obtained data are interpreted in terms of differences in the spatial energy deposition by sparsely and densely ionizing radiation. (author)

  12. Quality of Life Among Radiation Workers

    International Nuclear Information System (INIS)

    Quality of life (QOL) is a general term applied to the totality of physical, psychological, and social functioning. The World Health Organization (WHO) regards health as a state of complete physical, mental, and social well being, and not merely the absence of disease. Every person's life is different, and thus the way in which each person experiences a QOL is unique. Individuals lead complex lives that have many dimensions. A QOL approach recognizes that there are many different aspects of living that may contribute to quality. In this study, Quality of life was evaluated using the Short Form 36 (SF-36) questionnaire for one hundred and fifty radiation workers who handled ionizing radiation for at least twelve years, and one hundred fifty control individuals who did not knowingly come in contact with any radiation source., the QOL effects on work and achievements were also evaluated. Results revealed that radiation workers have lower quality of life compared to those who never come in contact with a radiation source

  13. Minimization of radiation by quality assurance

    International Nuclear Information System (INIS)

    In the Federal Republic of Germany there is such a high safety standard for nuclear power plants that very low limiting values for emissions and, consequently, low effective doses were laid down which are in part even lower than the level acknowledged internationally and by the European Community. The greatest part of civilization-dependent radiation exposure of the population is caused by the use of ionizing radiation in medicine, here again by X-ray diagnostics. But the use of radioactive materials for diagnostic and therapeutic purposes also requires corresponding rules, accommodated in the draft amendment for the Radiation Protection Ordinance subject to the principle that any unnecessary radiation exposure of persons is to be avoided and must where possible be restricted in accordance with the state of science and technology. In therapy, especially, radiation has to be handled in accordance with the requirements of medical science. Minimization and optimization of the use of radiation calls for additional and further training of personnel and, moreover, for efforts towards quality assurance, i.e. monitoring of devices and systems and its documentation, strict indications to be established by doctors, gauged, tested devices, low-dose nuclides, and optimized radiation plans, as well as risk-benefit assessments again and again. (TRV)

  14. Biophysical Aspects of Radiation Quality. Second Panel Report

    International Nuclear Information System (INIS)

    quality, the variation of radiosensitivity in the mammalian cell cycle and the relative biological effectiveness (RBE) of neutrons at very low doses. In addition to presenting and discussing their scientific work the participants found it desirable to give a brief survey of radiation biophysics under the headings of Radiobiology, Medical and Radiation Protection Applications, and Basic Physical Sciences. It is hoped that this survey, together with the papers, discussions and recommendations, will make a further impact on radiation biology studies and the Agency's programme in this field

  15. Quality-of-life assessment following surgery with or without postoperative radiation therapy for squamous cell carcinoma of the tongue base

    International Nuclear Information System (INIS)

    Purpose/Objective: To evaluate the quality-of-life after surgery with or without postoperative radiation therapy for carcinoma of the tongue base. Materials and Methods: At the 1995 ASTRO meeting, the University of Florida and MSKCC reported the quality-of-life (QOL) functional outcome of patients treated with primary radiation therapy (RT) for squamous cell carcinoma of the tongue base (BOT). Relatively little data evaluating the QOL following primary surgery has been published. Between January 1974 and December 1993, 89 patients (pts) underwent surgery alone (65 pts) or surgery combined with postoperative radiation therapy (24 pts) for tongue base cancer. Twenty-seven pts were alive at last contact. Three pts have been lost to follow-up and three pts declined to participate in the QOL assessment. Twenty-one pts consented to QOL assessment. Their median follow-up is 5.4 years (range 2.0-20.8 years). These patients completed: 1) the Performance Status Scale for Head and Neck Cancer Patients (PSS), a measure of ability to eat in public, understandability of speech, and normalcy of diet (scale 0-100, best score = 100); and 2) Functional Assessment of Cancer Therapy (FACT) (scale 0-28 for physical and social well-being, and 0-20 for emotional well-being, higher number=best score). Pathologic T stage was T1-7, T2-10, T3-3, T4-1. Twenty patients had ipsilateral neck dissection and 6 had bilateral neck dissection. The 8 patients who were treated with adjuvant RT received a median dose of 60 Gy. Prior to treatment, 62% had either full or part-time employment with a median annual income of $10,000-$40,000. Results: Mean PSS scores for all patients were 82 for eating in public, 92 for understandability of speech, and 78 for normalcy of diet. Normalcy of diet was significantly better in the surgery alone group than in the adjuvant RT group (91 vs. 56, p=0.0005). The ability to eat in public (88 vs. 72, p=NS) and understandability of speech (96 vs. 84, p=NS) did not differ

  16. Radiation qualities for tests in diagnostic radiology

    International Nuclear Information System (INIS)

    The paper gives an overview on the essential parameters, which have to be taken into account for designing radiation qualities suitable for tests in diagnostic radiology. It is divided into two sections the first of which is devoted to fields with small amounts of scattered radiation. These fields can be characterized reasonably well by the terms beam attenuation and beam hardening. The two effects occur always simultaneously with a preference towards attenuation for filtering materials of low atomic number and vice versa. The second part is devoted to fields with abundant scattered radiation. In these cases the field diameter and the distance from the exit surface of the phantom are additional important parameters. Possible sources of errors of measurement in such fields are discussed, some recommendations on their usage are given

  17. Impact of different beam set-up methods on quality of intensity modulated radiation therapy in non-small cell lung cancer

    International Nuclear Information System (INIS)

    Objective: To investigate whether the change of beam set-up methods will influence the dosimetric quality of intensity modulated radiation therapy (IMRT) for non-small cell lung cancer (NSCLC). Methods: Twenty-one stage I-III NSCLC patients were selected for this study. The technique of step and shoot was used and three different beam set-up methods were chosen for IMRT planning including IMRT-7 with nine equal-spaced beams angled 0 degree, 51 degree, 102 degree, 153 degree, 204 degree, 255 degree and 306 degree; IMRT-5 with five equal-spaced beams angled 0 degree, 72 degree, 144 degree, 216 degree and 288 degree; and IMRT-5m which was created from IMRT-7 but excluded 2 fields (51 degree and 102 degree were omitted if there was lesion in the right lung, while 255 degree and 306 degree were excluded if there was lesion in the left lung). The dose constrains of normal lungs for IMRT were set according to V5-V60 of normal lungs obtained from the same patient's actually treated 3D-CRT dose volume histogram. The prescription dose for IMRT started from 65 Gy, and then escalated or decreased step by step by 2 Gy once a time until best plan was obtained. Results: For normal lung dose, IMRT-5m had lower V5-V25 than the other two groups; but there was no significant difference in V30-V40. IMRT-5 was the worst for V45-V60; and mean lung dose was lowest in IMRT-5m. Dose parameters of esophagus and spinal cord, target conformity index, and total monitor units were all similar among difference plans. IMRT-5m had lowest heart V40 compared to the other two groups. For target heterogeneity index, IMRT-5 was higher than IMRT-7, but there were no significant differences among IMRT-5m, IMRT-5 and IMRT-7. Compared to 3D-CRT, the prescription dose could be increased by (5.1±4.6) Gy for IMRT-7, (3.1±5.3) Gy for IMRT-5, and (5.5±4.8) Gy for IMRT-5m. Conclusions: Fewer beams and modified beam angles could result in similar, even better plan quality. (authors)

  18. Radiation Dosimetry Management: Quality Assurance and Investigations

    International Nuclear Information System (INIS)

    Full text: In a litigation-prone society, it is prudent for any business to evaluate its potential exposure to legal action, initiated by either an employee or a member of the general public. This potential is exacerbated when the phobia of radiation exposure and radioactive materials is interjected into the equation. This phobia is fuelled by the perceived risks of radiation exposure, be they fact or fantasy. With the current cancer incidence rate being approximately 1 in every 2.5 individuals (for all types of cancer), it is imperative that all facilities take a proactive look at their business vulnerability. When radiation exposure is the issue, records documentation is a critical factor, and a significant amount of effort should be expended to implement a comprehensive records management system. A comprehensive Radiation Dosimetry Management Program is essential if a business is going to mitigate any regulatory or legal intervention. This lecture will address appropriate Records Quality Assurance, and, the appropriate requirements for investigations of dosimetry results. (author)

  19. Biophysics of NASA radiation quality factors

    International Nuclear Information System (INIS)

    NASA has implemented new radiation quality factors (QFs) for projecting cancer risks from space radiation exposures to astronauts. The NASA QFs are based on particle track structure concepts with parameters derived from available radiobiology data, and NASA introduces distinct QFs for solid cancer and leukaemia risk estimates. The NASA model was reviewed by the US National Research Council and approved for use by NASA for risk assessment for International Space Station missions and trade studies of future exploration missions to Mars and other destinations. A key feature of the NASA QFs is to represent the uncertainty in the QF assessments and evaluate the importance of the QF uncertainty to overall uncertainties in cancer risk projections. In this article, the biophysical basis for the probability distribution functions representing QF uncertainties was reviewed, and approaches needed to reduce uncertainties were discussed. (author)

  20. Cell Phone RF Radiation

    Science.gov (United States)

    Abdul-Razzaq, Wathiq

    2015-01-01

    In a recent article in "Physics Today," Meredith and Redish emphasized the need to make introductory physics courses beneficial for life sciences majors. In this study, a lab activity is proposed to measure the intensity of electromagnetic waves emitted by cell phones and connect these measurements to various standards, biological…

  1. Radiation Quality, Like Art, Consists in Drawing the Line Somewhere

    OpenAIRE

    Kunos, Charles A.; Petersen, Ivy A.

    2013-01-01

    The architects of phase I radiochemotherapy development programs impose a semblance of structured radiation “intensity” and adverse event predictability upon radiation-anticancer agent interactions whose natural complexity and improper mixing would otherwise lead to dire health consequences. It is incumbent upon radiation oncology investigators to pledge radiation quality and safety to the participants of radiochemotherapy trials. Measures of radiation quality and safety may be tools to scrut...

  2. Radiation quality, like art, consists in drawing the line somewhere

    OpenAIRE

    CharlesKunos; IvyAPetersen

    2013-01-01

    Summary The architects of phase I radiochemotherapy development programs impose a semblance of structured radiation ‘intensity’ and adverse event predictability upon radiation-anticancer agent interactions whose natural complexity and improper mixing would otherwise lead to dire health consequences. It is incumbent upon radiation oncology investigators to pledge radiation quality and safety to the participants of radiochemotherapy trials. Measures of radiation quality and safety may be to...

  3. Radiation therapy for intracranial germ cell tumors

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Shingo; Hayakawa, Kazushige; Tsuchiya, Miwako; Arai, Masahiko; Kazumoto, Tomoko; Niibe, Hideo; Tamura, Masaru

    1988-04-01

    The results of radiation therapy in 31 patients with intracranial germ cell tumors have been analyzed. The five-year survival rates were 70.1 % for germinomas and 38.1 % for teratomas. Three patients with germinoma have since died of spinal seeding. The prophylactic irradiation of the spinal canal has been found effective in protecting spinal seeding, since no relapse of germinoma has been observed in cases that received entire neuraxis iradiation, whereas teratomas and marker (AFP, HCG) positive tumors did not respond favorably to radiation therapy, and the cause of death in these patients has been local failure. Long-term survivors over 3 years after radiation therapy have been determined as having a good quality of life.

  4. Radiation quality factor of spherical antennas with material cores

    DEFF Research Database (Denmark)

    Hansen, Troels Vejle; Kim, Oleksiy S.; Breinbjerg, Olav

    2011-01-01

    This paper gives a description of the radiation quality factor and resonances of spherical antennas with material cores. Conditions for cavity and radiating resonances are given, and a theoretical description of the radiation quality factor, as well as simple expressions describing the relative...... permeability and permittivity for an antenna of fixed electrical size is performed....

  5. Quality assurance in radiation therapy: physical aspects

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, H.

    1984-06-01

    The present status of the quality assurance work regarding the physical aspects in radiation treatment is discussed. In particular, the situation in Europe is surveyed. An analysis of the errors in the delivered absorbed dose to a specified point in the irradiated patient shows that the uncertainty, to approximately the same degree, depends on the dose distribution determination, the dose planning and the patient irradiation. Following the procedure generally in use, the overall uncertainty will be about 8%. The random uncertainties are estimated as one standard deviation and non-random uncertainties to corresponding degree of uncertainty. It is argued that this level must be improved. Furthermore, dose intercomparisons show that in reality much larger errors occur in clinical practice. Different means to improve the situation are discussed.

  6. Mechanisms of radiation-induced neoplastic cell transformation

    International Nuclear Information System (INIS)

    Studies with cultured mammalian cells demonstrated clearly that radiation can transform cells directly and can enhance the cell transformation by oncogenic DNA viruses. In general, high-LET heavy-ion radiation can be more effective than X and gamma rays in inducing neoplastic cell transformation. Various experimental results indicate that radiation-induced DNA damage, most likely double-strand breaks, is important for both the initiation of cell transformation and for the enhancement of viral transformation. Some of the transformation and enhancement lesions can be repaired properly in the cell, and the amount of irrepairable lesions produced by a given dose depends on the quality of radiation. An inhibition of repair processes with chemical agents can increase the transformation frequency of cells exposed to radiation and/or oncogenic viruses, suggesting that repair mechanisms may play an important role in the radiation transformation. The progression of radiation-transformed cells appears to be a long and complicated process that can be modulated by some nonmutagenic chemical agents, e.g., DMSO. Normal cells can inhibit the expression of transforming properties of tumorigenic cells through an as yet unknown mechanism. The progression and expression of transformation may involve some epigenetic changes in the irradiated cells. 38 references, 15 figures, 1 table

  7. Phototherapy appliances, their ultraviolet radiation and quality assurance of phototherapy

    International Nuclear Information System (INIS)

    Artificial UV radiation (UVR) is used in the treatment of psoriasis and other skin diseases. Long term phototherapy is associated to increased risk of squamous cell carcinoma. This report gives a short review of biological effects of UVR and technical aspects of phototherapy units. The phototherapy units used in Finnish Central hospitals are described and the measured UVR dose rates of these units are presented. In addition, the UVR meters used in hospitals are described and the calibration factors are given for UVR dose rate measurements: Finally, recommendations are given for the quality assurance of photo-therapy units as well as for assessing UVR doses of patients. (orig.)

  8. Space radiation effects on plant and mammalian cells

    Science.gov (United States)

    Arena, C.; De Micco, V.; Macaeva, E.; Quintens, R.

    2014-11-01

    The study of the effects of ionizing radiation on organisms is related to different research aims. The current review emphasizes the studies on the effects of different doses of sparsely and densely ionizing radiation on living organisms, with the final purpose of highlighting specific and common effects of space radiation in mammals and plants. This topic is extremely relevant in the context of radiation protection from space environment. The response of different organisms to ionizing radiation depends on the radiation quality/dose and/or the intrinsic characteristics of the living system. Macromolecules, in particular DNA, are the critical targets of radiation, even if there is a strong difference between damages encountered by plant and mammalian cells. The differences in structure and metabolism between the two cell types are responsible for the higher resistance of the plant cell compared with its animal counterpart. In this review, we report some recent findings from studies performed in Space or on Earth, simulating space-like levels of radiation with ground-based facilities, to understand the effect of ionizing radiation on mammalian and plant cells. In particular, our attention is focused on genetic alterations and repair mechanisms in mammalian cells and on structures and mechanisms conferring radioresistance to plant cells.

  9. Predicted solar cell edge radiation effects

    International Nuclear Information System (INIS)

    The Advanced Solar Cell Orbital Test (ASCOT) will test six types of solar cells in a high energy proton environment. During the design of the experiment a question was raised about the effects of proton radiation incident on the edge of the solar cells and whether edge radiation shielding was required. Historical geosynchronous data indicated that edge radiation damage is not detectable over the normal end of life solar cell degradation; however because the ASCOT radiation environment has a much higher and more energetic fluence of protons, considerably more edge damage is expected. A computer analysis of the problem was made by modeling the expected radiation damage at the cell edge and using a network model of small interconnected solar cells to predict degradation in the cell's electrical output. The model indicated that the deepest penetration of edge radiation was at the top of the cell near the junction where the protons have access to the cell through the low density cell/cover adhesive layer. The network model indicated that the cells could tolerate high fluences at their edge as long as there was high electrical resistance between the edge radiated region and the contact system on top of the cell. The predicted edge radiation related loss was less than 2% of maximum power for GaAs/Ge solar cells. As a result, no edge radiation protection was used for ASCOT

  10. Stem cell-based therapies for acute radiation syndrome

    International Nuclear Information System (INIS)

    Exposure to high doses of ionizing radiation in the event of accidental or intentional incident such as nuclear/radiological terrorism can lead to debilitating injuries to multiple organs resulting in death within days depending on the amount of radiation dose and the quality of radiation. Unfortunately, there is not a single FDA-licensed drug approved against acute radiation injury. The RadStem Center for Medical Countermeasures against Radiation (RadStem CMGR) program at Einstein is developing stem cell-based therapies to treat acute radiation syndrome (ARS). We have demonstrated that intravenous transplantation of bone marrow-derived and adipose-derived stromal cells, consisting of a mixture of mesenchymal, endothelial and myeloid progenitors can mitigate mice exposed to whole body irradiation of 12 Gy or whole abdominal irradiation of up to 20 Gy. We identified a variety of growth and differentiation factors that individually is unable to improve survival of animals exposed to lethal irradiation, but when administered sequentially mitigates radiation injury and improves survival. We termed this phenomenon as synthetic survival and describe a new paradigm whereby the 'synthetic survival' of irradiated tissues can be promoted by systemic administration of growth factors to amplify residual stem cell clonogens post-radiation exposure, followed by a differentiation factor that favors tissue stem cell differentiation. Synthetic survival can be applied to mitigate lethal radiation injury in multiple organs following radiation-induced hematopoeitic, gastrointestinal and pulmonary syndromes. (author)

  11. Radiation-induced genetic effects in germ cells of mammals

    International Nuclear Information System (INIS)

    The possibility of the induction of malformations after radiation exposure during pregnancy is a serious radiation hazard. The objectives of the project refer to radiation exposure of germ cell stages with different radiation qualities (X-, gamma- or beta-rays) and different dose rates (1 Gy/min and below 0.01 Gy/min). The uterine content is examined on day 19 of gestation as to early and late resorptions, dead and malformed fetuses and fetal weights are determined. (R.P.) 4 refs., 1 tab

  12. Fishing for radiation quality: chromosome aberrations and the role of radiation track structure

    International Nuclear Information System (INIS)

    The yield of chromosome aberrations is not only dependent on dose but also on radiation quality, with high linear energy transfer (LET) typically having a greater biological effectiveness per unit dose than those of low-LET radiation. Differences in radiation track structure and cell morphology can also lead to quantitative differences in the spectra of the resulting chromosomal rearrangements, especially at low doses associated with typical human exposures. The development of combinatorial fluorescent labelling techniques (such as mFISH and mBAND) has helped to reveal the complexity of rearrangements, showing increasing complexity of observed rearrangements with increasing LET but has a resolution limited to ∼10 MBp. High-LET particles have not only been shown to produce clustered sites of DNA damage but also produce multiple correlated breaks along its path resulting in DNA fragments smaller than the resolution of these techniques. Additionally, studies have shown that the vast majority of radiation-induced HPRT mutations were also not detectable using fluorescent in situ hybridisation (FISH) techniques, with correlation of breaks along the track being reflected in the complexity of mutations, with intra- and inter-chromosomal insertions, and inversions occurring at the sites of some of the deletions. Therefore, the analysis of visible chromosomal rearrangements observed using current FISH techniques is likely to represent just the tip of the iceberg, considerably underestimating the extent and complexity of radiation induced rearrangements. (author)

  13. Improvement of bacteriological quality of frozen shrimp by gamma radiation

    International Nuclear Information System (INIS)

    The possible use of gamma irradiation at doses of 2 and 3 kGy to improve bacteriological quality of frozen shrimp was investigated. The effects of gamma irradiation on salmonella viability in frozen shrimp and on sensory quality of frozen shrimp were also evaluated. Treatment of frozen shrimp at 3 kGy reduced bacterial load by 2 log cycles and eliminated Enterobacteriaceae, E. coli, V. parahaemolyticus, and S. aureus. Coliform was still present in a 3 kGy treated samples but in a very small percentage and the count was less than 10 cell/g. Salmonella was not detected in either irradiated or non-irradiated frozen shrimp. A difference in radiation resistance was noted among five salmonella serotypes tested. S. lexington was the most resistant and S. anatum was the least resistant. Salmonella resistance was higher in frozen inoculated shrimp than in refrigerated inoculated shrimp. A dose of at least 4.2 kGy is required for a seven log cycle reduction of salmonella contamination in frozen shrimp. Off-flavors were produced in frozen shrimp irradiated at 4.2 kGy but diminished during subsequent frozen storage. However, irradiated frozen shrimp was of acceptable quality for at least four months. Dosage at 3 kGy appeared to be sufficient for improving bacteriological quality of frozen shrimp

  14. Low- and high-LET radiation drives clonal expansion of lung progenitor cells in vivo

    OpenAIRE

    Farin, Alicia M.; Manzo, Nicholas D.; Kirsch, David G.; Stripp, Barry R.

    2015-01-01

    Abundant populations of epithelial progenitor cells maintain the epithelium along the proximal-to-distal axis of the airway. Exposure of lung tissue to ionizing radiation leads to tissue remodeling and potential cancer initiation or progression. However, little is known about the effects of ionizing radiation on airway epithelial progenitor cells. We hypothesized that ionizing radiation exposure will alter the behavior of airway epithelial progenitor cells in a radiation dose- and quality-dep...

  15. Radiolabeled blood cells: radiation dosimetry and significance

    International Nuclear Information System (INIS)

    Over the past few years blood cells labeled with In-111 have become increasingly useful in clinical diagnosis and biomedical research. Indium-111 by the virtue of its physical characteristics and ability to bind to cell cytoplasmic components, provides an excellent cell tracer and thereby, allows investigators to monitor in vivo cell distribution by external imaging and help determine a course of regimen in treating life threatening diseases. Due to natural phenomena such as margination, blood pool, and reticuloendothelial cell activity, in the normal state, depending upon the cell type and the quality of cell preparations, 30%-50% of the administered radioactivity is immediately distributed in the liver, spleen and bone marrow. Over a period of time the radioactivity in these organs slightly increases and decays with a physical half-life of In-111. The resulting radiation dose to these organs ranges between 1-25 rads/mCi In-111 administered. The authors have developed a new In-111 labeling technique which preserves platelet ultrastructure and shown that human lymphocytes labeled with In-111 in mixed leukocytes preparations a) are only 0.003% of the total -body lymphocytes population and b) are killed. The consequence if any may be considered insignificant, particularly because 5.6% metaphases from normal men and 6.5% metaphases from normal women in the US have at least one chromosome aberration. Calculations have shown that the risk of fatal hematological malignancy, over a 30 year period, in recipients of 100 million lymphocytes labeled with 100 μCi In-111 is 1/million patients studied. This risk is less than 0.025% of the 1981 spontaneous cancer patient rate in the country. 32 references, 10 tables

  16. Organoleptic quality and antioxidant status of radiation processed food commodities

    International Nuclear Information System (INIS)

    Effect of radiation processing on the organoleptic qualities such as aroma, taste and colour as well as antioxidant status of various food classes such as beverages (monsooned coffee), spices (nutmeg), fruits (pomegranate), oil seeds (soybean) and vegetables (guar beans) was investigated. The factors responsible for these attributes were shown to be liberated from their glycosidic precursors during radiation processing, thus resulted in an enhancement of organoleptic quality and antioxidant status. (author)

  17. Nanodosimetry-based quality factors for radiation protection in space.

    Science.gov (United States)

    Schulte, Reinhard W; Wroe, Andrew J; Bashkirov, Vladimir A; Garty, Guy Y; Breskin, Amos; Chechik, Rachel; Shchemelinin, Sergei; Gargioni, Elisabetta; Grosswendt, Bernd; Rosenfeld, Anatoly B

    2008-01-01

    Evaluation and monitoring of the cancer risk from space radiation exposure is a crucial requirement for the success of long-term space missions. One important task in the risk calculation is to properly weigh the various components of space radiation dose according to their assumed contribution to the cancer risk relative to the risk associated with radiation of low ionization density. Currently, quality factors of radiation both on the ground and in space are defined by national and international commissions based on existing radiobiological data and presumed knowledge of the ionization density distribution of the radiation field at a given point of interest. This approach makes the determination of the average quality factor ofa given radiation field a rather complex task. In this contribution, we investigate the possibility to define quality factors of space radiation exposure based on nanodosimetric data. The underlying formalism of the determination of quality factors on the basis of nanodosimetric data is described, and quality factors for protons and ions (helium and carbon) of different energies based on simulated nanodosimetric data are presented. The value and limitations of this approach are discussed. PMID:19205298

  18. Nanodosimetry-based quality factors for radiation protection in space

    International Nuclear Information System (INIS)

    Evaluation and monitoring of the cancer risk from space radiation exposure is a crucial requirement for the success of long-term space missions. One important task in the risk calculation is to properly weigh the various components of space radiation dose according to their assumed contribution to the cancer risk relative to the risk associated with radiation of low ionization density. Currently, quality factors of radiation both on the ground and in space are defined by national and international commissions based on existing radiobiological data and presumed knowledge of the ionization density distribution of the radiation field at a given point of interest. This approach makes the determination of the average quality factor of a given radiation field a rather complex task. In this contribution, we investigate the possibility to define quality factors of space radiation exposure based on nanodosimetric data. The underlying formalism of the determination of quality factors on the basis of nanodosimetric data is described, and quality factors for protons and ions (helium and carbon) of different energies based on simulated nanodosimetric data are presented. The value and limitations of this approach are discussed. (orig.)

  19. Nanodosimetry-based quality factors for radiation protection in space

    Energy Technology Data Exchange (ETDEWEB)

    Schulte, Reinhard W.; Wroe, Andrew J.; Bashkirov, Vladimir A. [Dept. of Radiation Medicine, Loma Linda Univ. Medical Center, Loma Linda, CA (United States); Garty, Guy Y. [RARAF, Columbia Univ., Irvington, NY (United States); Breskin, Amos; Chechik, Rachel; Shchemelinin, Sergei [Dept. of Particle Physics, Weizmann Inst. of Science, Rehovot (Israel); Gargioni, Elisabetta; Grosswendt, Bernd [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany); Rosenfeld, Anatoly B. [Centre for Medical Radiation Physics, Univ. of Wollongong, NSW (Australia)

    2008-07-01

    Evaluation and monitoring of the cancer risk from space radiation exposure is a crucial requirement for the success of long-term space missions. One important task in the risk calculation is to properly weigh the various components of space radiation dose according to their assumed contribution to the cancer risk relative to the risk associated with radiation of low ionization density. Currently, quality factors of radiation both on the ground and in space are defined by national and international commissions based on existing radiobiological data and presumed knowledge of the ionization density distribution of the radiation field at a given point of interest. This approach makes the determination of the average quality factor of a given radiation field a rather complex task. In this contribution, we investigate the possibility to define quality factors of space radiation exposure based on nanodosimetric data. The underlying formalism of the determination of quality factors on the basis of nanodosimetric data is described, and quality factors for protons and ions (helium and carbon) of different energies based on simulated nanodosimetric data are presented. The value and limitations of this approach are discussed. (orig.)

  20. PROCESSES FOR QUALITY IMPROVEMENTS IN RADIATION ONCOLOGY CLINICAL TRIALS

    OpenAIRE

    FitzGerald, TJ; Urie, Marcia; Ulin, Kenneth; Laurie, Fran; Yorty, Jeffrey; Hanusik, Richard; Kessel, Sandy; Jodoin, Maryann Bishop; Osagie, Gani; Giulia Cicchetti, M.; Pieters, Richard; McCarten, Kathleen; Rosen, Nancy

    2008-01-01

    Quality assurance in radiation therapy has been an integral aspect of cooperative group clinical trials since 1970. In early clinical trials data acquisition was non-uniform and inconsistent; computational models for radiation dose calculation varied significantly. Process improvements developed for data acquisition, credentialing, and data management have provided the necessary infrastructure for uniform data. With continued improvement in the technology and delivery of radiation therapy, ev...

  1. Alternative Physical Quality Parameters Influences Effectiveness of Lower Doses Ionizing Radiation

    Science.gov (United States)

    Yousif, Abubaker Ali; Bahari, Ismail Bin; Yasir, Muhamad Samudi

    2011-03-01

    It has been proved in many studied that the absorbed dose is not good physical quality parameter to quantify the radiation effects at lower doses. However relative biological effect (RBE) is still used as a major parameter of radiation effectiveness. Whereas linear energy transfer (LET) is inadequate physical parameter, therefore the weaknesses in using RBE-LET system for radiation protection have been investigated. Secondary data of V79 has reanalyzed to help complement the inadequacy current method in assessing cell inactivation at lower doses. Results of analysis show that the effectiveness of densely ionizing radiation is better quantified using mean free path (λ).

  2. Target cells involved in radiation and radiation leukemia virus leukemogenesis

    International Nuclear Information System (INIS)

    Comparative studies concerned with the induction and early proliferation phases of preleukemic cells in relation to host environments using radiation or radiation leukemia virus as the leukemogenic agents, indicated different developmental pathways. The lack of thymus in mice exposed to fractionated irradiation did not prevent preleukemic cell induction but did interfere with the incidence of RadLV induced preleukemic cells. Thymus removal within several days following RadLV inoculation prevented the establishment of preleukemic cells in the bone marrow. The radiation induced preleukemic cells in the bone marrow. The radiation induced preleukemic cells were not lysed by anti-Thy-1.2 serum treatment and guinea pig complement whereas the RadLV induced ones were lysed to different degrees. Elimination of Thy-1.2 bearing cells from the virus induced preleukemic population reduced the development of overt T leukemias of donor origin. The thymus seemed of essential importance for establishing the proliferation of RadLV induced preleukemic cells but not for those induced by fractionated irradiation

  3. Factors which influence quality of life in patients with non-small cell lung cancer (NSCLC): A radiation therapy oncology group study (RTOG 89-01)

    International Nuclear Information System (INIS)

    Purpose: Prospectively evaluate the quality of life (QOL) of patients with NSCLC participating in a randomized phase III study conducted by the RTOG and Eastern Cooperative Oncology Group. Determine the factors which influence QOL during and post therapy. Materials and Methods: From (4(90)) to (4(94)) to 75 patients (pts) were randomized on RTOG 89-01 between a regimen containing radiation therapy (RT) versus a regimen containing surgery (S). All pts received induction vinblastine and cisplatin, followed by either S or RT and consolidation chemotherapy (CT). Pts were given the self-assessment QOL forms prior to the start of therapy, post induction CT, post RT or S, and periodically during follow-up. Two questionnaires were used: Functional Assessment of Cancer Therapy for lung cancer patients (FACT-L) and Functional Living Index-Cancer (FLIC). The FACT-L consists of 44 questions covering 6 domains (physical, social, and emotional well-being, relationship with physician, fulfilment, and lung cancer specific concerns), FLIC contains 22 questions summing to one total score. Results: 51 pts participated in the QOL endpoint, 24 were excluded: 3 pts refused, institution did not administer QOL questionnaires in 9 pts, 3 completed QOL after start of therapy, 1 institution refused to participate, 5 questionnaires were incomplete/unusable, 1 pt could not read English, and 2 were ineligible for treatment. Participation in QOL was not predicted by any pretreatment characteristic. Women had worse pretreatment QOL (p<0.005, by FLIC) and more problems with disease-related symptoms (p<0.005, by FACT) than men. Pts with KPS 90-100 had better pretreatment QOL than pts with KPS 60-80 (p<0.025, FLIC). Neither race, marital status, education level, age, prior weight loss, nor disease symptoms statistically significantly influenced pretreatment QOL. Initial QOL did not predict overall survival. FACT-L was reported on 25 pts post induction CT. Follow-up FACT-L was available on 12 pts

  4. Repair of radiation damage in mammalian cells

    International Nuclear Information System (INIS)

    The responses, such as survival, mutation, and carcinogenesis, of mammalian cells and tissues to radiation are dependent not only on the magnitude of the damage to macromolecular structures - DNA, RNA, protein, and membranes - but on the rates of macromolecular syntheses of cells relative to the half-lives of the damages. Cells possess a number of mechanisms for repairing damage to DNA. If the repair systems are rapid and error free, cells can tolerate much larger doses than if repair is slow or error prone. It is important to understand the effects of radiation and the repair of radiation damage because there exist reasonable amounts of epidemiological data that permits the construction of dose-response curves for humans. The shapes of such curves or the magnitude of the response will depend on repair. Radiation damage is emphasized because: (a) radiation dosimetry, with all its uncertainties for populations, is excellent compared to chemical dosimetry; (b) a number of cancer-prone diseases are known in which there are defects in DNA repair and radiation results in more chromosomal damage in cells from such individuals than in cells from normal individuals; (c) in some cases, specific radiation products in DNA have been correlated with biological effects, and (d) many chemical effects seem to mimic radiation effects. A further reason for emphasizing damage to DNA is the wealth of experimental evidence indicating that damages to DNA can be initiating events in carcinogenesis

  5. Haemopoietic cell renewal in radiation fields.

    Science.gov (United States)

    Fliedner, T M; Nothdurft, W; Tibken, B; Hofer, E; Weiss, M; Kindler, H

    1994-10-01

    Space flight activities are inevitably associated with a chronic exposure of astronauts to a complex mixture of ionising radiation. Although no acute radiation consequences are to be expected as a rule, the possibility of Solar Particle Events (SPE) associated with relatively high doses of radiation (1 or more Gray) cannot be excluded. It is the responsibility of physicians in charge of the health of astronauts to evaluate before, during and after space flight activities the functional status of haemopoietic cell renewal. Chronic low level exposure of dogs indicate that daily gamma-exposure doses below about 2 cGy are tolerated for several years as far as blood cell concentrations are concerned. However, the stem cell pool may be severely affected. The maintenance of sufficient blood cell counts is possible only through increased cell production to compensate for the radiation inflicted excess cell loss. This behaviour of haemopoietic cell renewal during chronic low level exposure can be simulated by bioengineering models of granulocytopoiesis. It is possible to define a "turbulence region" for cell loss rates, below which an prolonged adaptation to increased radiation fields can be expected to be tolerated. On the basis of these experimental results, it is recommended to develop new biological indicators to monitor haemopoietic cell renewal at the level of the stem cell pool using blood stem cells in addition to the determination of cytokine concentrations in the serum (and other novel approaches). To prepare for unexpected haemopoietic effects during prolonged space missions, research should be increased to modify the radiation sensitivity of haemopoietic stem cells (for instance by the application of certain regulatory molecules). In addition, a "blood stem cell bank" might be established for the autologous storage of stem cells and for use in space activities keeping them in a radiation protected container. PMID:11539991

  6. Haemopoietic cell renewal in radiation fields

    Science.gov (United States)

    Fliedner, T. M.; Nothdurft, W.; Tibken, B.; Hofer, E.; Weiss, M.; Kindler, H.

    1994-10-01

    Space flight activities are inevitably associated with a chronic exposure of astronauts to a complex mixture of ionising radiation. Although no acute radiation consequences are to be expected as a rule, the possibility of Solar Particle Events (SPE) associated with relatively high doses of radiation (1 or more Gray) cannot be excluded. It is the responsibility of physicians in charge of the health of astronauts to evaluate before, during and after space flight activities the functional status of haemopoietic cell renewal. Chronic low level exposure of dogs indicate that daily gamma-exposure doses below about 2 cGy are tolerated for several years as far as blood cell concentrations are concerned. However, the stem cell pool may be severely affected. The maintenance of sufficient blood cell counts is possible only through increased cell production to compensate for the radiation inflicted excess cell loss. This behaviour of haemopoietic cell renewal during chronic low level exposure can be simulated by bioengineering models of granulocytopoiesis. It is possible to define a ``turbulence region'' for cell loss rates, below which an prolonged adaptation to increased radiation fields can be expected to be tolerated. On the basis of these experimental results, it is recommended to develop new biological indicators to monitor haemopoietic cell renewal at the level of the stem cell pool using blood stem cells in addition to the determination of cytokine concentrations in the serum (and other novel approaches). To prepare for unexpected haemopoietic effects during prolonged space missions, research should be increased to modify the radiation sensitivity of haemopoietic stem cells (for instance by the application of certain regulatory molecules). In addition, a ``blood stem cell bank'' might be established for the autologous storage of stem cells and for use in space activities keeping them in a radiation protected container.

  7. Quality assurance of radiation therapy machines

    International Nuclear Information System (INIS)

    Due to the modifications of components, to unexpected breakage of elements or to electronic dysfunctions, the performance of radiotherapy machines may decrease with age. Quality Assurance procedures and maintenance program are necessary to guarantee the performances. For linear accelerators, modus operandi of control tests and their frequency are based on regulations and recommendations widely published, that are presented here. Concerning accessories, especially those recently developed (multi-leaf collimators, dynamic wedges,...), recommendations remains to be defined. Simple tests are proposed. Concerning numerical imaging systems, widely used for three dimensional dosimetry, image quality and geometry controls must be performed with fantom tests. For portal imaging, a quality assurance program is proposed. A strict and complete Quality Assurance program is essential to guarantee quality and safety of the treatment. A regular control of linear accelerator is one of the important component of this program. It suppose the implementation of permanent tests procedures, periodically modified following technological progresses and treatment techniques. Measurements must be sensible to variations below the tolerance level defined during the installation process. The analysis of the variations of measurements with time are an objective criterion of quality. (author)

  8. Radiation Enhances Regulatory T Cell Representation

    International Nuclear Information System (INIS)

    Purpose: Immunotherapy could be a useful adjunct to standard cytotoxic therapies such as radiation in patients with micrometastatic disease, although successful integration of immunotherapy into treatment protocols will require further understanding of how standard therapies affect the generation of antitumor immune responses. This study was undertaken to evaluate the impact of radiation therapy (RT) on immunosuppressive T regulatory (Treg) cells. Methods and Materials: Treg cells were identified as a CD4+CD25hiFoxp3+ lymphocyte subset, and their fate was followed in a murine TRAMP C1 model of prostate cancer in mice with and without RT. Results: CD4+CD25hiFoxp3+ Treg cells increased in immune organs after local leg or whole-body radiation. A large part, but not all, of this increase after leg-only irradiation could be ascribed to radiation scatter and Treg cells being intrinsically more radiation resistant than other lymphocyte subpopulations, resulting in their selection. Their functional activity on a per-cell basis was not affected by radiation exposure. Similar findings were made with mice receiving local RT to murine prostate tumors growing in the leg. The importance of the Treg cell population in the response to RT was shown by systemic elimination of Treg cells, which greatly enhanced radiation-induced tumor regression. Conclusions: We conclude that Treg cells are more resistant to radiation than other lymphocytes, resulting in their preferential increase. Treg cells may form an important homeostatic mechanism for tissues injured by radiation, and in a tumor context, they may assist in immune evasion during therapy. Targeting this population may allow enhancement of radiotherapeutic benefit through immune modulation.

  9. Radiation Enhances Regulatory T Cell Representation

    Energy Technology Data Exchange (ETDEWEB)

    Kachikwu, Evelyn L.; Iwamoto, Keisuke S.; Liao, Yu-Pei; DeMarco, John J.; Agazaryan, Nzhde [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA (United States); Economou, James S. [Department of Surgical Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA (United States); McBride, William H. [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA (United States); Schaue, Doerthe, E-mail: dschaue@mednet.ucla.edu [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA (United States)

    2011-11-15

    Purpose: Immunotherapy could be a useful adjunct to standard cytotoxic therapies such as radiation in patients with micrometastatic disease, although successful integration of immunotherapy into treatment protocols will require further understanding of how standard therapies affect the generation of antitumor immune responses. This study was undertaken to evaluate the impact of radiation therapy (RT) on immunosuppressive T regulatory (Treg) cells. Methods and Materials: Treg cells were identified as a CD4{sup +}CD25{sup hi}Foxp3{sup +} lymphocyte subset, and their fate was followed in a murine TRAMP C1 model of prostate cancer in mice with and without RT. Results: CD4{sup +}CD25{sup hi}Foxp3{sup +} Treg cells increased in immune organs after local leg or whole-body radiation. A large part, but not all, of this increase after leg-only irradiation could be ascribed to radiation scatter and Treg cells being intrinsically more radiation resistant than other lymphocyte subpopulations, resulting in their selection. Their functional activity on a per-cell basis was not affected by radiation exposure. Similar findings were made with mice receiving local RT to murine prostate tumors growing in the leg. The importance of the Treg cell population in the response to RT was shown by systemic elimination of Treg cells, which greatly enhanced radiation-induced tumor regression. Conclusions: We conclude that Treg cells are more resistant to radiation than other lymphocytes, resulting in their preferential increase. Treg cells may form an important homeostatic mechanism for tissues injured by radiation, and in a tumor context, they may assist in immune evasion during therapy. Targeting this population may allow enhancement of radiotherapeutic benefit through immune modulation.

  10. The role of nuclear factor κB in the cellular response to different radiation qualities

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Kristina

    2013-04-11

    Radiation is currently one of the most important limiting factors for manned space flight. During such missions, there is a constant exposure to low doses of galactic cosmic radiation and in particular high-energy heavy ions. Together this is associated with an increased cancer risk which currently cannot be sufficiently reduced by shielding. As such, cellular radiation response needs to be further studied in order to improve risk estimation and develop appropriate countermeasures. It has been shown that exposure of human cells to accelerated heavy ions, in fluences that can be reached during long-term missions, leads to activation of the Nuclear Factor κB (NF-κB) pathway. Heavy ions with a linear energy transfer (LET) of 90 to 300 keV/μm were most effective in activating NF-κB. NF-κB as an important modulating factor in the cellular radiation response could improve cellular survival after heavy ion exposure, thereby influencing the cancer risk of astronauts. The NF-κB pathway may be a potential pharmacological target in the mitigation of radiation response during space missions; such as the prevention of massive cell death after high dose irradiation (acute effects), in addition to neoplastic cell transformation during chronic low-dose exposure (late effects). The aim of this work was to examine the role of NF-κB in the cellular response to space-relevant radiation. Firstly, NF-κB activation in human embryonic kidney cells (HEK) after exposure to different radiation qualities and quantities was investigated. Key elements of different NF-κB sub-pathways were chemically inhibited to analyze their role in NF-κB activation induced by low and high LET ionizing radiation. Finally a cell line, stably transfected with a plasmid coding for a short-hairpin RNA (shRNA) for a knockdown of the NF-κB subunit RelA, was established to assess the role of RelA in the cellular response to space-relevant radiation. The knockdown was verified on several levels and the cell

  11. The role of nuclear factor κB in the cellular response to different radiation qualities

    International Nuclear Information System (INIS)

    Radiation is currently one of the most important limiting factors for manned space flight. During such missions, there is a constant exposure to low doses of galactic cosmic radiation and in particular high-energy heavy ions. Together this is associated with an increased cancer risk which currently cannot be sufficiently reduced by shielding. As such, cellular radiation response needs to be further studied in order to improve risk estimation and develop appropriate countermeasures. It has been shown that exposure of human cells to accelerated heavy ions, in fluences that can be reached during long-term missions, leads to activation of the Nuclear Factor κB (NF-κB) pathway. Heavy ions with a linear energy transfer (LET) of 90 to 300 keV/μm were most effective in activating NF-κB. NF-κB as an important modulating factor in the cellular radiation response could improve cellular survival after heavy ion exposure, thereby influencing the cancer risk of astronauts. The NF-κB pathway may be a potential pharmacological target in the mitigation of radiation response during space missions; such as the prevention of massive cell death after high dose irradiation (acute effects), in addition to neoplastic cell transformation during chronic low-dose exposure (late effects). The aim of this work was to examine the role of NF-κB in the cellular response to space-relevant radiation. Firstly, NF-κB activation in human embryonic kidney cells (HEK) after exposure to different radiation qualities and quantities was investigated. Key elements of different NF-κB sub-pathways were chemically inhibited to analyze their role in NF-κB activation induced by low and high LET ionizing radiation. Finally a cell line, stably transfected with a plasmid coding for a short-hairpin RNA (shRNA) for a knockdown of the NF-κB subunit RelA, was established to assess the role of RelA in the cellular response to space-relevant radiation. The knockdown was verified on several levels and the cell

  12. Quality audit of 137Cs reference radiation field for radiation protection calibrations

    International Nuclear Information System (INIS)

    Radiation Standards Section, Radiation Safety Systems Division, Bhabha Atomic Research Centre, Mumbai is a member of the IAEA/WHO Network of SSDLs. It periodically participates in the TLD postal dose quality audits conducted by IAEA as a part of the quality assurance program. TLD samples are dispatched to the participants, by IAEA, for irradiating it to a known dose. These samples are then evaluated at the IAEA Dosimetry Laboratory and the results are conveyed to the participating laboratories. The results of the quality audit are part of the quality assurance program which give confidence to the dosimetry procedures adopted

  13. The myth of cell phone radiation

    OpenAIRE

    Natarajan, Vasant

    2012-01-01

    We discuss the purported link between cell-phone radiation and cancer. We show that it is inconsistent with the photoelectric effect, and that epidemiological studies of any link have no scientific basis.

  14. The myth of cell phone radiation

    CERN Document Server

    Natarajan, Vasant

    2012-01-01

    We discuss the purported link between cell phone radiation and cancer. We show that it is inconsistent with the photoelectric effect, and that epidemiological studies of any link have no scientific basis.

  15. Quality management in radiation protection: Introduction of a quality management system at PSI, Switzerland

    International Nuclear Information System (INIS)

    The introduction of a Quality Management System for the radiation protection organization of the Paul-Scherrer-Institute at Villigen/Switzerland is substantiated and described. Hints are given for an effective procedure during the initiation phase. (orig.)

  16. High Radiation Resistance IMM Solar Cell

    Science.gov (United States)

    Pan, Noren

    2015-01-01

    Due to high launch costs, weight reduction is a key driver for the development of new solar cell technologies suitable for space applications. This project is developing a unique triple-junction inverted metamorphic multijunction (IMM) technology that enables the manufacture of very lightweight, low-cost InGaAsP-based multijunction solar cells. This IMM technology consists of indium (In) and phosphorous (P) solar cell active materials, which are designed to improve the radiation-resistant properties of the triple-junction solar cell while maintaining high efficiency. The intrinsic radiation hardness of InP materials makes them of great interest for building solar cells suitable for deployment in harsh radiation environments, such as medium Earth orbit and missions to the outer planets. NASA Glenn's recently developed epitaxial lift-off (ELO) process also will be applied to this new structure, which will enable the fabrication of the IMM structure without the substrate.

  17. Radiation Dosimetry for Quality Control of Food Preservation and Disinfestation

    DEFF Research Database (Denmark)

    McLaughlin, W.L.; Miller, Arne; Uribe, R.M.

    1983-01-01

    In the use of x and gamma rays and scanned electron beams to extend the shelf life of food by delay of sprouting and ripening, killing of microbes, and control of insect population, quality assurance is provided by standardized radiation dosimetry. By strategic placement of calibrated dosimeters...... parameters (e.g. conveyor speed) to meet changes that occur in product and source parameters (e.g. bulk density and radiation spectrum). Routine dosimetry methods and certain corrections of dosimetry data may be selected for the radiations used in typical food processes....

  18. Evaluation of the environmental quality objective 'A Safe Radiation Environment'

    International Nuclear Information System (INIS)

    The evaluation of the environmental quality objective 'A Safe Radiation Environment' is a contribution to the Environmental Objective Council's assessment of progress towards the national environmental quality objectives. The report describes and evaluates the radiation environment in Sweden, the regulatory instruments, measures carried out and the monitoring programmes. Furthermore, the possibility of achieving the objective and its interim targets is evaluated. New measures and means of control are proposed. The proposals are directed to the government and Parliament, national authorities and other stakeholders in society. The Swedish Radiation Protection Authority (SSI) considers it possible to achieve the objective, but additional efforts are required to ensure success. Environmental monitoring, research on health effects of radiation and supervision are still important areas. Intensified efforts will be needed to change attitudes towards suntanning. Changes in the formulation of the objective and its interim targets are suggested. Today only protection against radiation in the external environment is covered by the objective. Radiation protection work has to consider all. SSI therefore suggests that the objective should extend to include workplaces and indoor environment. For the three interim targets included in 'A Safe Radiation Environment', changes are suggested for the interim targets for radioactive substances and electromagnetic fields. No change is suggested for the interim target for skin cancer

  19. Biophysical aspects of radiation quality. Report of a panel

    International Nuclear Information System (INIS)

    In radiation biology it is essential to understand the different effectiveness, or radiation quality, of various kinds of ionizing radiations on living systems. Research work on this subject has only been done fairly recently; it includes the experimental determination of local energy absorption in tissue (microdosimetry), investigations of physical and chemical factors modifying radiation effect, and theoretical interpretations of dose effect relationships. This work is not only of high academic interest but is also very important for the evaluation of radiation hazards in mixed radiation fields, near high-energy particles, and in space. A Panel of experts was convened from 29 March to 2 April, 1965, in Vienna at the Headquarters of the International Atomic Energy Agency under the chairmanship of Professor H. H. Rossi, to discuss current research on the subject. The participants were prominent biologists and biophysicists representing the most active groups working on radiation quality. At the end of the meeting it was clear that the Panel had fulfilled a most useful purpose by stimulating the exchange of ideas and improving the contacts between workers in different parts of the world, and by proposing lines of development for basic research in radiobiology

  20. Quality factors for space radiation: A new approach

    Science.gov (United States)

    Borak, Thomas B.; Heilbronn, Lawrence H.; Townsend, Lawrence W.; McBeth, Rafe A.; de Wet, Wouter

    2014-04-01

    NASA has derived new models for radiological risk assessment based on epidemiological data and radiation biology including differences in Relative Biological Effectiveness for leukemia and solid tumors. Comprehensive approaches were used to develop new risk cross sections and the extension of these into recommendations for risk assessment during space missions. The methodology relies on published data generated and the extensive research initiative managed by the NASA Human Research Program (HRP) and reviewed by the National Academy of Sciences. This resulted in recommendations for revised specifications of quality factors, QNASA (Z , β) in terms of track structure concepts that extend beyond LET alone. The new paradigm for quality factors placed demands on radiation monitoring procedures that are not satisfied by existing dosimetry systems or particle spectrometers that are practical for space exploration where mass, volume, band width and power consumption are highly constrained. We have proposed a new definition of quality factors that relaxes the requirements for identifying charge, Z, and velocity, β, of the incident radiation while still preserving the functional form of the inherent risk functions. The departure from the exact description of QNASA (Z , β) is that the revised values are new functions of LET for solid cancers and leukemia. We present the motivation and process for developing the revised quality factors. We describe results of extensive simulations using GCR distributions in free space as well as the resulting spectra of primary and secondary particles behind aluminum shields and penetration through water. In all cases the revised dose averaged quality factors agreed with those based on the values obtained using QNASA (Z , β). This provides confidence that emerging technologies for space radiation dosimetry can provide real time measurements of dose and dose equivalent while satisfying constraints on size, mass, power and bandwidth. The

  1. Quality factors for space radiation: A new approach.

    Science.gov (United States)

    Borak, Thomas B; Heilbronn, Lawrence H; Townsend, Lawrence W; McBeth, Rafe A; de Wet, Wouter

    2014-04-01

    NASA has derived new models for radiological risk assessment based on epidemiological data and radiation biology including differences in Relative Biological Effectiveness for leukemia and solid tumors. Comprehensive approaches were used to develop new risk cross sections and the extension of these into recommendations for risk assessment during space missions. The methodology relies on published data generated and the extensive research initiative managed by the NASA Human Research Program (HRP) and reviewed by the National Academy of Sciences. This resulted in recommendations for revised specifications of quality factors, QNASA(Z,β) in terms of track structure concepts that extend beyond LET alone. The new paradigm for quality factors placed demands on radiation monitoring procedures that are not satisfied by existing dosimetry systems or particle spectrometers that are practical for space exploration where mass, volume, band width and power consumption are highly constrained. We have proposed a new definition of quality factors that relaxes the requirements for identifying charge, Z, and velocity, β, of the incident radiation while still preserving the functional form of the inherent risk functions. The departure from the exact description of QNASA(Z,β) is that the revised values are new functions of LET for solid cancers and leukemia. We present the motivation and process for developing the revised quality factors. We describe results of extensive simulations using GCR distributions in free space as well as the resulting spectra of primary and secondary particles behind aluminum shields and penetration through water. In all cases the revised dose averaged quality factors agreed with those based on the values obtained using QNASA(Z,β). This provides confidence that emerging technologies for space radiation dosimetry can provide real time measurements of dose and dose equivalent while satisfying constraints on size, mass, power and bandwidth. The revised

  2. Albendazole sensitizes cancer cells to ionizing radiation

    International Nuclear Information System (INIS)

    Brain metastases afflict approximately half of patients with metastatic melanoma (MM) and small cell lung cancer (SCLC) and represent the direct cause of death in 60 to 70% of those affected. Standard of care remains ineffective in both types of cancer with the challenge of overcoming the blood brain barrier (BBB) exacerbating the clinical problem. Our purpose is to determine and characterize the potential of albendazole (ABZ) as a cytotoxic and radiosensitizing agent against MM and SCLC cells. Here, ABZ's mechanism of action as a DNA damaging and microtubule disrupting agent is assessed through analysis of histone H2AX phosphorylation and cell cyle progression. The cytotoxicity of ABZ alone and in combination with radiation therapy is determined though clonogenic cell survival assays in a panel of MM and SCLC cell lines. We further establish ABZ's ability to act synergistically as a radio-sensitizer through combination index calculations and apoptotic measurements of poly (ADP-ribose) polymerase (PARP) cleavage. ABZ induces DNA damage as measured by increased H2AX phosphorylation. ABZ inhibits the growth of MM and SCLC at clinically achievable plasma concentrations. At these concentrations, ABZ arrests MM and SCLC cells in the G2/M phase of the cell cycle after 12 hours of treatment. Exploiting the notion that cells in the G2/M phase are the most sensitive to radiation therapy, we show that treatment of MM and SCLC cells treated with ABZ renders them more sensitive to radiation in a synergistic fashion. Additionally, MM and SCLC cells co-treated with ABZ and radiation exhibit increased apoptosis at 72 hours. Our study suggests that the orally available antihelminthic ABZ acts as a potent radiosensitizer in MM and SCLC cell lines. Further evaluation of ABZ in combination with radiation as a potential treatment for MM and SCLC brain metastases is warranted

  3. Analysis of the influence of radiation quality on the effectiveness of small doses for induction of reproductive death and chromosome aberrations in mammalian cells

    International Nuclear Information System (INIS)

    A comparison of RBE - LET relations are made for reproductive death and chromosome aberrations in mammalian cells, as a means of providing insight into the type of mechanisms involved. An analysis of the survival curves for X-rays and gamma rays is discussed and a schematic representation is presented of differences in the dependence of the effectiveness per unit dose on LET, for which data were derived from experiments with X-rays, gamma rays, fast neutrons and heavy ions. (Auth./C.F.)

  4. Breast cancer stem cells and radiation

    Science.gov (United States)

    Phillips, Tiffany Marie

    2007-12-01

    The present studies explore the response of breast cancer stem cells (BCSC's) to radiation and the implications for clinical cancer treatment. Current cancer therapy eliminates bulky tumor mass but may fail to eradicate a critical tumor initiating cell population termed "cancer stem cells". These cells are potentially responsible for tumor formation, metastasis, and recurrence. Recently cancer stem cells have been prospectively identified in various malignancies, including breast cancer. The breast cancer stem cell has been identified by the surface markers CD44+/CD24 -(low). In vitro mammosphere cultures allow for the enrichment of the cancer stem cell population and were utilized in order to study differential characteristics of BCSC's. Initial studies found that BCSC's display increased radiation resistance as compared to other non-stem tumor cells. This resistance was accompanied by decreased H2AX phosphorylation, decreased reactive oxygen species formation, and increased phosphorylation of the checkpoint protein Chk1. These studies suggest differential DNA damage and repair within the BCSC population. Studies then examined the consequences of fractionated radiation on the BCSC population and found a two-fold increase in BCSC's following 5 x 3Gy. This observation begins to tie cancer stem cell self-renewal to the clinical stem cell phenomenon of accelerated repopulation. Accelerated repopulation is observed when treatment gaps increase between sequential fractions of radiotherapy and may be due to cancer stem cell symmetric self-renewal. The balance between asymmetric and symmetric stem cell division is vital for proper maintenance; deregulation is likely linked to cancer initiation and progression. The developmental Notch-1 pathway was found to regulate BCSC division. Over-expressing the constitutively active Notch-1-ICD in MCF7 cells produced an increase in the BCSC population. Additionally, radiation was observed to increase the expression of the Notch-1

  5. Radiation Dosimetry for Quality Control of Food Preservation and Disinfestation

    DEFF Research Database (Denmark)

    McLaughlin, W.L.; Miller, Arne; Uribe, R.M.

    1983-01-01

    In the use of x and gamma rays and scanned electron beams to extend the shelf life of food by delay of sprouting and ripening, killing of microbes, and control of insect population, quality assurance is provided by standardized radiation dosimetry. By strategic placement of calibrated dosimeters...

  6. Certification. Tool for quality? Market and client for radiation experts

    International Nuclear Information System (INIS)

    The role and impact of certification in the advisory work of radiation experts is briefly outlined. Certification is a guarantee for quality of the advice or a product in case there is a client and a market. In cases where there is not a client or a market certification will lead to 'window-dressing and a bureaucratic system

  7. Quality Characteristics of Dried Bananas Produced with Infrared Radiation Technology

    Science.gov (United States)

    Browning of fruits during drying is a major quality concern. The enzyme polyphenol oxidase has been found to be the main cause of browning in bananas. Infrared radiation (IR) drying could be used to minimize enzymatic browning hence eliminating the need for pre-treatments. This study was to inves...

  8. Quality audit service of the IAEA for radiation processing dosimetry

    International Nuclear Information System (INIS)

    The mandate of the International Atomic Energy Agency includes assistance to Member States to establish nuclear technologies safely and effectively. In pursuit of this, a quality audit service for dosimetry relevant to radiation processing was initiated as a key element of the High-Dose Standardization Programme of the IAEA. The standardization of dosimetry for radiation processing provides a justification for the regulatory approval of irradiated products and their unrestricted international trade. In recent times, the Agency's Dosimetry Laboratory has placed concentrated effort towards establishing a quality assurance programme based on the ISO 9000 series documents. The need for reliable and accurate dosimetry for radiation processing is increasing in Member States and we can envisage a definite role for the SSDLs in such a programme. (author). 10 refs, 3 figs

  9. The radiation effects on the living cell

    International Nuclear Information System (INIS)

    This publication is a presentation of particular points discussed during the colloquium of the 15-18 june 1999, for which scientific researches are performed at the CEA/CNRS. They deal with the radiobiology, for the radiation effects on living matter; with the DNA, for the knowledge and repair mechanisms on cells submitted to ionizing radiations; with the exposition to UV in correlation with neoplasms; with the P53 gene which is a tumour suppressor. (A.L.B.)

  10. Radiation dosimetry for quality control of food preservation and disinfestation

    Science.gov (United States)

    McLaughlin, W. L.; Miller, A.; Uribe, R. M.

    In the use of x and gamma rays and scanned electron beams to extend the shelf life of food by delay of sprouting and ripening, killing of microbes, and control of insect population, quality assurance is provided by standardized radiation dosimetry. By strategic placement of calibrated dosimeters that are sufficiently stable and reproducible, it is possible to monitor minimum and maximum radiation absorbed dose levels and dose uniformity for a given processed foodstuff. The dosimetry procedure is especially important in the commisioning of a process and in making adjustments of process parameters (e.g. conveyor speed) to meet changes that occur in product and source parameters (e.g. bulk density and radiation spectrum). Routine dosimetry methods and certain corrections of dosimetry data may be selected for the radiations used in typical food processes.

  11. Adult Mesenchymal Stem Cells and Radiation Injury.

    Science.gov (United States)

    Kiang, Juliann G

    2016-08-01

    Recent understanding of the cellular and molecular signaling activations in adult mesenchymal stem cells (MSCs) has provided new insights into their potential clinical applications, particularly for tissue repair and regeneration. This review focuses on these advances, specifically in the context of self-renewal for tissue repair and recovery after radiation injury. Thus far, MSCs have been characterized extensively and shown to be useful in mitigation and therapy for acute radiation syndrome and cognitive dysfunction. Use of MSCs for treating radiation injury alone or in combination with additional trauma is foreseeable. PMID:27356065

  12. Influence of Detector Radiation Damage on CR Mammography Quality Control.

    Science.gov (United States)

    Moriwaki, Atsumi; Ishii, Mie; Terazono, Shiho; Arao, Keiko; Ishii, Rie; Sanada, Taizo; Yoshida, Akira

    2016-05-01

    Recently, radiation damage to the detector apparatus employed in computed radiography (CR) mammography has become problematic. The CR system and the imaging plate (IP) applied to quality control (QC) program were also used in clinical mammography in our hospital, and the IP to which radiation damage has occurred was used for approximately 5 years (approximately 13,000 exposures). We considered using previously acquired QC image data, which is stored in a server, to investigate the influence of radiation damage to an IP. The mammography unit employed in this study was a phase contrast mammography (PCM) Mermaid (KONICA MINOLTA) system. The QC image was made newly, and it was output in the film, and thereafter the optical density of the step-phantom image was measured. An input (digital value)-output (optical density) conversion curve was plotted using the obtained data. The digital values were then converted to optical density values using a reference optical density vs. digital value curve. When a high radiation dose was applied directly, radiation damage occurred at a position on the IP where no object was present. Daily QC for mammography is conducted using an American College of Radiology (ACR) accreditation phantom and acrylic disc, and an environmental background density measurement is performed as one of the management indexes. In this study, the radiation damage sustained by the acrylic disc was shown to differ from that of the background. Thus, it was revealed that QC results are influenced by radiation damage. PMID:27211088

  13. Physical measurements for quality control in industrial radiation sterilization

    International Nuclear Information System (INIS)

    The use of ionizing radiation has brought about a growing industry for the sterilization of disposable surgical equipment, medical supplies, and containers for biological specimens. For many products, irradiation has become an alternative to autoclaving or gas treatment by ethylene oxide. Over fifteen years of experience with industrial sterilization by cobalt-60 gamma radiation have shown that radiation methods provide a clear advantage over gas sterilization, in that sterilization can be performed on non-permeable sealed packages. Moreover, regulatory agencies, such as the Food and Drug Administration in the U.S.A., are reappraising the requirements for sterility assurance. For products released to the public, consideration is now being given to the use of physical dosimetry, i.e., the measurement of radiation dose by physical methods. This is based on a knowledge of the microbial burden of the product before sterilization and on the probability of killing microorganisms by a given radiation dose. Because physical dosimetry is easier to control and less complicated than biological tests, it may be considered in the future the basis for quality assurance of the sterilized product. Some of the problems associated with standardized measurement techniques in radiation sterilization include the choice of dosimetry and its calibration, as well as methods and procedures used to minimize errors due to variations in radiation flux density, source geometry with respect to the product, and environmental factors. (author)

  14. Quality control and quality assurance in radiation medicine in the Republic of Moldova

    International Nuclear Information System (INIS)

    Quality Health care results from translating fundamental bench discoveries and making them available to patients. During the past decade, 'molecular imaging' has emerged both as a new tool/technology and as a research and clinical discipline. Molecular imaging is an interdisciplinary approach involving biologist, physicist, physicians, mathematicians, radio chemists and other specialists who have joined forces for better understanding and visualizing of both normal physiological processes and the molecular processes preceding the morphological manifestations of disease in vivo. It is interesting to note, that despite major advances in imaging technology, cancer mortality has remained largely unchanged over the last three decades. Imaging has thus far enabled us to look through a magnifying glass at disease processes but has failed to dramatically influence disease outcomes. Emerging data suggest that molecular PET imaging is about to change this situation. Quality assurance is based on monitoring, measuring, evaluation, verification and recording of quantities, parameters and facts significant from the point of view of Radiation Protection. Quality assurance programs shall be established that provide, as appropriate: adequate assurance that the specified requirements relating to protection and safety are satisfied and quality control mechanisms and procedures for reviewing and assessing the overall effectiveness of protection and safety. The Republic of Moldova with the support of the International Atomic Energy Agency perform the quality assurance and quality control procedures in the frame of the Technical Cooperation Regional Projects RER-6-012 ''Quality Assurance and Quality Control in Radiation Oncology'', and RER-6-011 'Thematic Program on Nuclear Medicine'. The Ministry of Health and Social Protection carry out the National Project 'Ensuring Radiation Safety and Protection of the Patients' the principal goal being the Quality Assurance and Quality Control in

  15. Quality assurance in individual monitoring of ionizing radiation

    International Nuclear Information System (INIS)

    In todays world, where competition gets tougher, there is a growing consciousness of Quality Assurance (QA) and Quality Control (QC) being key elements to success. This does not only apply o manufacturing of industrial products, it is equally true for public services. Because of the increasing awareness in our modern societies of the quality of life and hence of optimal health care and general safety, it is also the general public that calls for 'products' of the highest possible quality. Good examples of the latter are the continuously improving safety standards for automobiles, for medical diagnostic imaging and for the working environment. Therefore, QA unquestionably plays a vital role in individual monitoring of ionizing radiation, especially since the media talked so many into some sort of radiation phobia. In the following an attempt is made to roughly outline some aspects that may come into play if QA is applied to routine personnel dosimetry. The author wants to emphasize that the subject, which has hardly been dealt with in the professional literature on radiation dosimetry, is a rather 'soft' one. There may be a large number of different approaches to QA, depending on special local situations and individual - sometimes national - views. It should therefore be considered as a general guide, provided in the form of (check)lists containing items of interest in routine monitoring

  16. Quality management system in the CIEMAT radiation dosimetry service

    International Nuclear Information System (INIS)

    This paper describes the activities realised by the CIEMAT Radiation Dosimetry Service (SDR) for the implementation of a quality management system (QMS) in order to achieve compliance with the requirements of ISO/IEC 17025 and to apply for the accreditation for testing measurements of radiation dose. SDR has decided the accreditation of the service as a whole and not for each of its component laboratories. This makes it necessary to design a QMS common to all, thus ensuring alignment and compliance with standard requirements, and simplifying routine works as possible. (authors)

  17. Radiation- induced aneuploidy in mammalian germ cells

    International Nuclear Information System (INIS)

    The ability of ionizing radiation to induce aneuploidy in mammalian germ cells has been investigated experimentally in the laboratory mouse using a variety of cytogenetic and genetic methods. These studies have provided unambiguous evidence of induced nondisjunction in both male and female germ cells when the effect of irradiation is screened in meiotic cells or preimplantation embryos. In contrast, however, cytogenetic analyses of post-implantation embryos and genetic assays for induced chromosome gains have not found a significant radiation effect. These apparently contradictory findings may be reconciled if (a) radiation induces tertiary rather than primary trisomy, or (b) induces embryo-lethal genetic damage, such as deletions, in addition to numerical anomalies. Either or both of these explanations may account for the apparent loss during gestation of radiation-induced trisomic embryos. Extrapolating from the information so far available, it seems unlikely that environmental exposure to low doses if low dose rate radiation will result in a detectable increase in the rate of aneuploidy in the human population. (author)

  18. Influence of radiation processing of grapes on wine quality

    International Nuclear Information System (INIS)

    Grapes (Var. Shiraz and Cabernet) were subjected to radiation processing (up to 2 kGy) and wines were prepared and matured (4 months, 15 °C). The wines were analyzed for chromatic characteristics, total anthocyanin (TA), phenolic (TP) and total antioxidant (TAC) content. Aroma of wines was analyzed by GC/MS and sensory analysis was carried out using descriptive analysis. TA, TP and TAC were 77, 31 and 37 percent higher for irradiated (1500 Gy) Cabernet wines, while irradiated Shiraz wines demonstrated 47, 18 and 19 percent higher TA, TP and TAC, respectively. HPLC-DAD analysis revealed that radiation processing of grapes resulted in increased extraction of phenolic constituents in wine with no qualitative changes. No major radiation induced changes were observed in aroma constituents of wine. Sensory analysis revealed that 1500 Gy irradiated samples had higher fruity and berry notes. Thus, radiation processing of grapes resulted in wines with improved organoleptic and antioxidant properties. - Highlights: • Grapes were subjected to radiation processing before wine making. • Wines from irradiated grapes had higher antioxidant and phenolics compared to control. • HPLC analysis confirmed improved extraction of phenolics due to radiation processing. • Aroma profile and sensory quality of control and irradiated wines were similar

  19. Radiation effects in mammalian cells in vitro

    International Nuclear Information System (INIS)

    The purpose of this research effort is to elucidate the mechanisms for the radiation-induced changes in mammalian cells that lead to cell death, mutation, neoplastic transformation, DNA damage, and chromosomal alterations. Of particular interest are the effects of low-dose-rate and fractionated irradiation on these end points with respect to the mechanisms whereby these effects are influenced by cellular repair processes, inhibitors, and promoters that act at the genetic or biochemical level. 17 refs

  20. Radiation therapy for intracranial germ cell tumor

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Wakako; Takizawa, Yoshikazu; Yoshida, Hiroshi; Aruga, Moriyo; Arimizu, Noboru (Chiba Univ. (Japan). School of Medicine); Itami, Jun

    1993-05-01

    From 1974 through 1988, 27 patients with intracranial germ cell tumor underwent radiotherapy in Chiba University Hospital. Radiation field encompassed the whole neuroaxis in 19 patients, the local area in 5, and the whole brain in 3. Overall 5-year survival rate of all 27 patients was 88.9%. There was no significant difference in 5-year overall survival rate between the patients who were treated by the neuroaxis radiation and by the more limited fields. The most significant prognostic factor was pathology of the tumors. Germinoma and histology-unknown tumors which showed good response to irradiation have more favorable prognosis than embryonal carcinoma and choriocarcinoma. From our data, three possibilities emerged: (1) some germinomas might be controlled by localized radiation; (2) optimal dose might be 45[approx]50 Gy; (3) if histology-unknown tumor has good response to radiation at 20 Gy, the tumor can be treated by the same way as germinoma. (author).

  1. Global quality control perspective for the physical and technical aspects of screen-film mammography - Image quality and radiation dose

    International Nuclear Information System (INIS)

    The systematic monitoring of image quality and radiation dose is an ultimate solution to ensuring the continuously high quality of mammography examination. At present several protocols exist around the world, and different test objects are used for quality control (QC) of the physical and technical aspects of screen-film mammography. This situation may lead to differences in radiation image quality and dose reported. This article reviews the global QC perspective for the physical and technical aspects of screen-film mammography with regard to image quality and radiation dose. It points out issues that must be resolved in terms of radiation dose and that also affect the comparison. (authors)

  2. Ultrastructural effects of radiation on cells and tissues: concluding remarks

    International Nuclear Information System (INIS)

    Concluding remarks which condense the subject matter covered in the preceding series of reports which indicate the complex nature of the biological response to ionizing radiation and the inherent difficulties associated with developing unifying concepts and definitions. The multiplicity of the major response variables, i.e., specimen type, radiation parameters, analytical approach and endpoints measured, is undoubtedly a major problem. In these studies, the specimens analyzed ranged from eucaryotic algae grown in vitro in suspension cultures to brain tissue of cancer patients. Specimens were irradiated with now fewer than seven types of ionizing radiation, which varied both in quality (i.e., high and low LET) and quantity (i.e., doses from 0.1 to 90 Gy). Exposure regimens included single, fractionated, and chronic exposures. Further, there were major differences in the analytical approach employed (e.g., structural and functional assays) and end-points measured (e.g., lethality, cell growth, surface topography, etc.)

  3. Effect of gamma radiation on honey quality control

    International Nuclear Information System (INIS)

    Honey is one of the most complex substances produced by bees, mainly from the nectar of flowers. Gamma radiation is a technique that can be used to decrease the number of microbiological problems associated with food and increase the shelf life of certain products. The objective of this study was to verify the effect of gamma radiation with source of cobalto-60 (10 kGy) on some parameters used in honey quality control. Seven samples of pure honey were obtained from local markets in Sao Paulo, Brazil, in 2007. The methods used are in accordance with Brazilian Regulations. The physicochemical parameters analyzed were: moisture, HMF, free acidity, pH, sugars and ash. The results showed that gamma radiation, in the dose mentioned above, did not cause significant physicochemical alterations.

  4. Effect of gamma radiation on honey quality control

    Science.gov (United States)

    Bera, A.; Almeida-Muradian, L. B.; Sabato, S. F.

    2009-07-01

    Honey is one of the most complex substances produced by bees, mainly from the nectar of flowers. Gamma radiation is a technique that can be used to decrease the number of microbiological problems associated with food and increase the shelf life of certain products. The objective of this study was to verify the effect of gamma radiation with source of cobalto-60 (10 kGy) on some parameters used in honey quality control. Seven samples of pure honey were obtained from local markets in Sao Paulo, Brazil, in 2007. The methods used are in accordance with Brazilian Regulations. The physicochemical parameters analyzed were: moisture, HMF, free acidity, pH, sugars and ash. The results showed that gamma radiation, in the dose mentioned above, did not cause significant physicochemical alterations.

  5. Effect of gamma radiation on honey quality control

    Energy Technology Data Exchange (ETDEWEB)

    Bera, A. [Radiation Technology Center, IPEN-CNEN/SP, A. Lineu Prestes, 2242, 05508-000 Sao Paulo (Brazil)], E-mail: berale@usp.br; Almeida-Muradian, L.B. [Av. Prof. Lineu Prestes, 580-Cidade Universitaria, Sao Paulo (Brazil); Sabato, S.F. [Radiation Technology Center, IPEN-CNEN/SP, A. Lineu Prestes, 2242, 05508-000 Sao Paulo (Brazil)], E-mail: sfsabato@ipen.br

    2009-07-15

    Honey is one of the most complex substances produced by bees, mainly from the nectar of flowers. Gamma radiation is a technique that can be used to decrease the number of microbiological problems associated with food and increase the shelf life of certain products. The objective of this study was to verify the effect of gamma radiation with source of cobalto-60 (10 kGy) on some parameters used in honey quality control. Seven samples of pure honey were obtained from local markets in Sao Paulo, Brazil, in 2007. The methods used are in accordance with Brazilian Regulations. The physicochemical parameters analyzed were: moisture, HMF, free acidity, pH, sugars and ash. The results showed that gamma radiation, in the dose mentioned above, did not cause significant physicochemical alterations.

  6. Radiation response of human hematopoietic cells

    International Nuclear Information System (INIS)

    The radiosensitivity and capacity to accumulate and repair sub-lethal damage has been studied in hematopoietic cell lines of human origin and in stem cells derived from blood and bone narrow of normal human donors. The results were analysed in terms of the linear quadratic and multitarget models. For the cell lines intrinsic radiosensitivity varied widely with D/sub o/'s ranging from 0.53 to 1.39 Gy. Five of the cell lines showed same capacity to accumulate sub-lethal damage and in three of these survival was enhanced by dose fractionation or reduction of dose rate. Among the cell lines of leukemic origin, several did not conform in one or more respects with the highly radiosensitive and repair deficient model associated with hematopoietic cells. There was no apparent correlation between radiation response and the phenotype (myeloid, lymphoid or undifferentiated) of the cell lines studied. Variability of radiation response and in some cases an unpredicted degree of radioresistance and capacity to repair sub-lethal damage has now been demonstrated for both cultured and primary explants of human leukemic cells. These observations have implications for the design of Total Body Irradiation protocols for use prior to bone narrow transplant

  7. Quality assurance and quality control program in individual monitoring service of the ENEA radiation protection institute

    International Nuclear Information System (INIS)

    Full text: The Individual Monitoring Service (IMS) of the ENEA Radiation Protection Institute, processes 80,000 dosemeters per year and is the only Italian Dosimetric Service supplying dosemeters for neutron radiation. It has been operating since the 1970s. The dosemeters have been designed, in house-developed and tested at ENEA Radiation Protection Institute throughout computational and experimental research. Since 2001 the ENEA IMS supplies personal dosemeters to assess Hp(d), which is required by Italian legislation (D.Lgs. 241/2000). In the 30 years of activity the ENEA-IMS has developed a learning of Quality Assurance (QA) and implemented Quality Control (QC) procedures to supply a reliable dosimetry service. In Italy, there are not yet requirements for approval of dosimetric service; however the application of a quality system to dosimetry is a quite established concept and few services have obtained certification in compliant with ISO 9000 standards, whereas accreditation in compliant with ISO 17025 is still on the way. In fact, although QA is sometimes a matter of common sense, the strategy for it towards the practical implementation of a QA program requires considerable thought. The IMS at ENEA has been always followed control procedures and internal tests to assure the quality of the whole system. Few examples will be given. The present paper describes the approach and actions which have been taken to 'translate' the actual 'ENEA Quality System' toward the accreditation according to ISO 17025. (author)

  8. A Method for Evaluating Quality Assurance Needs in Radiation Therapy

    International Nuclear Information System (INIS)

    The increasing complexity of modern radiation therapy planning and delivery techniques challenges traditional prescriptive quality control and quality assurance programs that ensure safety and reliability of treatment planning and delivery systems under all clinical scenarios. Until now quality management (QM) guidelines published by concerned organizations (e.g., American Association of Physicists in Medicine [AAPM], European Society for Therapeutic Radiology and Oncology [ESTRO], International Atomic Energy Agency [IAEA]) have focused on monitoring functional performance of radiotherapy equipment by measurable parameters, with tolerances set at strict but achievable values. In the modern environment, however, the number and sophistication of possible tests and measurements have increased dramatically. There is a need to prioritize QM activities in a way that will strike a balance between being reasonably achievable and optimally beneficial to patients. A systematic understanding of possible errors over the course of a radiation therapy treatment and the potential clinical impact of each is needed to direct limited resources in such a way to produce maximal benefit to the quality of patient care. Task Group 100 of the AAPM has taken a broad view of these issues and is developing a framework for designing QM activities, and hence allocating resources, based on estimates of clinical outcome, risk assessment, and failure modes. The report will provide guidelines on risk assessment approaches with emphasis on failure mode and effect analysis (FMEA) and an achievable QM program based on risk analysis. Examples of FMEA to intensity-modulated radiation therapy and high-dose-rate brachytherapy are presented. Recommendations on how to apply this new approach to individual clinics and further research and development will also be discussed

  9. Radiation protection measures for hot cell sanitation

    International Nuclear Information System (INIS)

    The cell 5 of the Hot Cell Facility of the Kernforschungszentrum Karlsruhe GmbH (KfK) was to be restored and reequipped after 12 years of operation. The decontamination work was first done remotely controlled and afterwards by 38 persons entering the cell, which took about 2 months. The radiation protection methods and personal dosimetry systems are described. At the beginning of the work the γ-dose rate amounted up to 900 mSv/h. After completion of the remotely controlled decontamination work the γ-dose rate decreased to 1.5 mSv/h. At that time the (α+β-contamination was 105 Bq/cm2. Till the end of the work the removable activity dropped to 102 - 103 Bq/cm2 for β-radiation, to 0.3 - 30 Bq/cm2 for α-radiation and the local dose rate to about 0.03 mSv/h. During the work the accumulated collective doses were listed for breast, hand, head, gonads and foot. In the figure the development with the time of the doses for breast and hand is shown. During restoration work of the cell the accumulated collective whole-body dose amounted to 30 mSv. (orig.)

  10. Physiological quality of rice seed submitted to gamma radiation

    International Nuclear Information System (INIS)

    The objective of this research was to evaluate the effects of the gamma radiation (60Co) on the physiological quality of rice seeds. The research was carried out through three tests; in the first test rice seeds were irradiated at dosages of 0; 1; 2.5 and 5Gy, while for the second and third tests the seeds were subjected to accelerated aging before being irradiated. For the second test the seeds were divided into wet and dry and both groups subjected to accelerated aging previous to irradiation at dosages of 0; 1; 2.5 and 5Gy. For the third test the seeds were dried after being subjected to accelerated aging, and then irradiated at dosages of 0, 10, 25 and 50Gy. To assess the physiological effects of the gamma radiation, all seeds were tested for germination and their germination speed index recorded. Seedling growth was graded through the measurement of the lengths of the first leaf and seminal root system and total seedling dry weight, across all tests. The enzymatic activity of acid phosphatase and alpha-amylase was measured on dry seeds from the second test. The results from all tests indicate that the applied gamma radiation dosages did not cause any changes to the physiological quality of rice seeds. (author)

  11. Radiation response in prostate cancer stem cells

    International Nuclear Information System (INIS)

    The full text of the publication follows. Introduction: Currently, there is no successful treatment for secondary prostate cancer. Resistance of secondary tumours and metastases to radiotherapy and chemotherapy might be explained by cancer stem cells (CSCs). Prostate (P) CSCs are rare cells defined by cell surface markers, CD133+, a2b1integrinhi and CD44+, and are capable of self-renewal, differentiation and invasion in vitro and tumour initiation in vivo. Hypothesis: PCSCs have an alternative DNA damage response following radiation and are resistant to radiation treatment. Methods: Primary prostate (benign and cancer) epithelial stem (SC) transit amplifying (TA, CD133-/a2b1integrinhi/CD44+) and committed basal (CB, CD133-/a2b1integrinlo/CD44+) cells were exposed to 2 Gy of radiation (IR) to induce a DNA damage response. Immunofluorescence was used to quantify nuclear foci, representative of DNA damage response proteins (g-H2AX, 53BP1, phosphorylated ATM/ATR substrates, phospho-Chk2Th68). Immunofluorescence was also used to co-stain for heterochromatin and DNA damage markers. Comet assays (neutral and alkaline) were used to directly assess DNA damage. Results: In benign and cancer cells, the SCs had a lower percentage of cells containing initial foci (30 min post-IR), compared to the TA and CB cells. At 24 h post-IR there was a reduced percentage of cells positive for foci in TA and CB cells suggesting repair. Whilst there were also signs of repair in benign SCs, in the PCSCs there was an increase in percentage of cells positive for foci at 24 h, indicative of a delayed damage response. Comet assays indicated that SCs sustain different kinds of DNA damage to TA and CB cells. Heterochromatin staining indicated that DNA damage foci preferentially formed in euchromatin. Future work: Further studies will include apoptosis and clonogenic assays to measure PCSC survival. In addition, PCSC chromatin status will be examined to elucidate DNA repair kinetics. If we are able

  12. Phytosphingosine can overcome resistance to ionizing radiation in ionizing radiation-resistant cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Park, Moon Taek; Choi, Jung A; Kim, Min Jeong; Bae, Sang Woo; Kang, Chang Mo; Cho, Chul Koo; Lee, Yun Sil; Lee, Su Jae [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Kang, Seong Man [Graduate School of Biotechnology, Korea University, Seoul (Korea, Republic of); Chung, Hee Yong [College of Medicine, Hanyang University, Seoul (Korea, Republic of)

    2004-07-01

    Although the majority of cancer cells are killed by inonizing radiation, certain types show resistance to it. We previously reported that phytosphingosine also induces apoptotic cell death in caspase dependent pathway in human cancer cells. In the present study, we examined whether phytosphingosine could overcome radiation resistance in the variant Jurkat clones. We first selected radiation-resistant Jurkat clones and examined cross-responsiveness of the clones between radiation and phytosphingosine. Treatment with phytosphingosine significantly did not affect apoptosis in all the clones, indicating that there seemed to be cross-resistance between radiation and phytosphingosine. Nevertheless, combined treatment of phytosphingosine with radiation synergistically enhanced killing of radiation-resistant cells, compared to radiation or phytosphingosine alone. The pan-caspase inhibitor z-VAD-fmk did not completely inhibit the synergistic cell killing induced by combined treatment of ionizing radiation and phytosphingosine. These results demonstrated that apoptosis induced by combined treatment of radiation and phytosphingosine in radiation-resistant cells was associated with caspase independent pathway. We also found that apoptotic cell death induced by combined treatment of ionizing radiation and phytosphingosine correlated to the increases of ROS. The enhancement of ROS generation induced the loss of mitochondria transmembrane potential. In conclusion, ROS generation in combined treatment of phytosphingosine with radiation significantly induced the translocation of AIF to nucleus from mitochondria, suggesting a potential clinical application of combination treatment of radiation and phytosphingosine to radiation-resistant cancer cells.

  13. Survey of Radiation Oncology Centres in Australia: report of the radiation oncology treatment quality program

    International Nuclear Information System (INIS)

    Full text: One of the first steps towards the development of a comprehensive quality program for radiation oncology in Australia has been a survey of practice. This paper reports on the results of the survey that should inform the development of standards for radiation oncology in Australia. A questionnaire of 108 questions spanning aspects of treatment services, equipment, staff, infrastructure and available quality systems was mailed to all facilities providing radiation treatment services in Australia (n = 45). Information of 42 sites was received by June 2006 providing data on 113 operational linear accelerators of which approximately 2/3 are equipped with multi-leaf collimators. More than 75% of facilities were participating in a formal quality assurance (QA) system, with 63% following a nationally or internationally recognised system. However, there was considerable variation in the availability of policies and procedures specific to quality aspects, and the review of these. Policies for monitoring patient waiting times for treatment were documented at just 71% of all facilities. Although 85% of all centres do, in fact, monitor machine throughput, the number and types of efficiency measures varied markedly, thereby limiting the comparative use of these results. Centres identified workload as the single most common factor responsible for limiting staff involvement in both QA processes and clinical trial participation. The data collected in this 'snapshot' survey provide a unique and comprehensive baseline for future comparisons and evaluation of changes

  14. Quality assurance in radiation processing. Dosimetry and control methods for radiation processing

    International Nuclear Information System (INIS)

    In the domain of radiation processing, the process control of the treatment is vitally important. In addition to the irradiation parameters checks, the main control in this process is the dose measurement in the three major aspects of quality control as described in different standards or guides: Irradiation facility qualification, Process validation, Routine process control. In this paper, an example is given for each aspect of the quality control for E-beam, X-Rays and gamma irradiation plant as well. These examples show that the use of a traceable and validated dosimetry system is the appropriate tool to realize irreproachable controls. The choice of the dosimeter type and its calibration against traceable laboratories is also essential to prove the quality of the radiation treatments. Concerning the dosimetry readout equipment, a flexible dosimeter analysis and computerized equipment is developed by Aerial in order to bring a major contribution to the quality control in the field of radiation processing. New developments for industrial ESR dosimetry readout equipment are presented. The adapted ESR software analyses the measured spectrum, checks the measurement parameters, and calculates the dosimetry system response, absorbed dose and associated uncertainty as well. (author)

  15. Quality assurance of environmental gamma radiation monitoring in Slovenia

    International Nuclear Information System (INIS)

    Environmental gamma radiation monitoring established in Slovenia consists of a network of multifunctional gamma monitors (MFMs) based on pairs of Geiger-Mueller counters and a network of measuring sites with high-sensitive thermoluminescence dosemeters. The measuring points are evenly spread across Slovenia, located at the meteorological stations and more densely on additional locations around the Krsko NPP. The MFM network has a 2-fold function with one sensor used for the purpose of early warning system in near surroundings of the NPP and the other, more sensitive, for natural radiation monitoring. The paper summarises activities to establish quality assurance of the environmental gamma radiation measurements in Slovenia, with a critical view of the results in comparison with the international standards and recommendations. While the results of linearity and energy dependence tests were satisfying, on-field intercomparison showed that the inherent signal of one of the monitors (MFM) has to be taken into account in the range of environmental background radiation. (authors)

  16. Quality assurance and quality control in Yugoslav environmental radiation protection metrological and legislation system

    International Nuclear Information System (INIS)

    Quality Assurance and Quality Control in Ionizing Radiation Metrology is performed through legal metrology, international and national intercomparation procedures and routine control of instrumentations and standards. Legal metrology defines methods, units, standards and instrumentations according to the technical and legal demands in all the aspects of Quality Assurance and Quality Control. According to international standards, legal metrology is performed by the national metrological organizations obliged to assure primary standards for physical quantities and their transfer to the user. In Yugoslavia the national metrological organization is the Federal Bureau for Measures and Precious Metals in charge to introduce primary and secondary standards and necessary legislations. International intercomparisons are within the domain of the Bureau International des Poids et Mesures, BIPM, in Sevre, France. Yugoslavia participated in international intercomparisons in December,1991 in Sevre and in Budapest, in 1995. In the last ten years, several national intercomparisons took place.Routine control of instrumentations and standards is regulated by the National Law On Units And Instrumentation ( Sl list SRJ, br.80/94, 28/96 i 12/98). Still, according to Organization International de Metrologie Legale OIML only a few of the 54 states-members (in 1996) developed the consistent legal system in the area of ionizing radiation concerning general public application, as it is the case for medical applications. Only 18 of them, mostly technically developed countries had legally regulated the control of instrumentations, units and quantities of ionizing radiation, including Yugoslavia

  17. Processes for Quality Improvements in Radiation Oncology Clinical Trials

    International Nuclear Information System (INIS)

    Quality assurance in radiotherapy (RT) has been an integral aspect of cooperative group clinical trials since 1970. In early clinical trials, data acquisition was nonuniform and inconsistent and computational models for radiation dose calculation varied significantly. Process improvements developed for data acquisition, credentialing, and data management have provided the necessary infrastructure for uniform data. With continued improvement in the technology and delivery of RT, evaluation processes for target definition, RT planning, and execution undergo constant review. As we move to multimodality image-based definitions of target volumes for protocols, future clinical trials will require near real-time image analysis and feedback to field investigators. The ability of quality assurance centers to meet these real-time challenges with robust electronic interaction platforms for imaging acquisition, review, archiving, and quantitative review of volumetric RT plans will be the primary challenge for future successful clinical trials

  18. Processes for quality improvements in radiation oncology clinical trials.

    Science.gov (United States)

    FitzGerald, T J; Urie, Marcia; Ulin, Kenneth; Laurie, Fran; Yorty, Jeffrey; Hanusik, Richard; Kessel, Sandy; Jodoin, Maryann Bishop; Osagie, Gani; Cicchetti, M Giulia; Pieters, Richard; McCarten, Kathleen; Rosen, Nancy

    2008-01-01

    Quality assurance in radiotherapy (RT) has been an integral aspect of cooperative group clinical trials since 1970. In early clinical trials, data acquisition was nonuniform and inconsistent and computational models for radiation dose calculation varied significantly. Process improvements developed for data acquisition, credentialing, and data management have provided the necessary infrastructure for uniform data. With continued improvement in the technology and delivery of RT, evaluation processes for target definition, RT planning, and execution undergo constant review. As we move to multimodality image-based definitions of target volumes for protocols, future clinical trials will require near real-time image analysis and feedback to field investigators. The ability of quality assurance centers to meet these real-time challenges with robust electronic interaction platforms for imaging acquisition, review, archiving, and quantitative review of volumetric RT plans will be the primary challenge for future successful clinical trials. PMID:18406943

  19. Improving the hygienic quality of chicken through radiation processing

    International Nuclear Information System (INIS)

    Irradiation is considered one of the most efficient technological processes for the reduction of microorganisms in food, It can be used to improve the safety of food products, and to extend their shelf lives. The aim of this study was to improve the hygienic quality of chicken through radiation processing. As part of the study a microbial assessment of broiler chicken thighs from three retail outlets (supermarket, local markets and farms) was conducted. The total viable count and total coliform counts were determined. Hygienic quality indicator organisms such as Escherichia coli, Salmonella and Staphylococcus aureus were isolated and microbial counts made. Radiation sensitivity test to determine the D10 (decimal reduction does) of E. coli on chicken at refrigeration and frozen temperature were conducted. D10 values were 0.22 ± 0.02 and 0.32 ± 0.03 kGy at refrigerated and frozen temperatures respectively. A storage test consisting of an uninoculated pack experiment and a challenge test to explore the effect of irradiation and frozen food storage on the total viable count and survival of E. coli was conducted. Chicken thigh samples were treated with 0 (non irradiated), 2.0, 4.0, 6.0 and 8.0 kGy of gamma irradiation and held frozen for 56 days. The control and irradiated samples were stored at -18 oC and underwent microbial analysis and sensory evaluation at 7 days intervals. It was observed that irradiation and frozen storage reduced microbial loads. There were significant differences in sensory quality characteristics during freezing storage in chicken meat. The combination of irradiation and frozen storage resulted in greater overall reductions on microbial loads thus improving hygienic quality. (au)

  20. Radiation-induced chromosomal instability in human mammary epithelial cells

    Science.gov (United States)

    Durante, M.; Grossi, G. F.; Yang, T. C.

    1996-01-01

    Karyotypes of human cells surviving X- and alpha-irradiation have been studied. Human mammary epithelial cells of the immortal, non-tumorigenic cell line H184B5 F5-1 M/10 were irradiated and surviving clones isolated and expanded in culture. Cytogenetic analysis was performed using dedicated software with an image analyzer. We have found that both high- and low-LET radiation induced chromosomal instability in long-term cultures, but with different characteristics. Complex chromosomal rearrangements were observed after X-rays, while chromosome loss predominated after alpha-particles. Deletions were observed in both cases. In clones derived from cells exposed to alpha-particles, some cells showed extensive chromosome breaking and double minutes. Genomic instability was correlated to delayed reproductive death and neoplastic transformation. These results indicate that chromosomal instability is a radiation-quality-dependent effect which could determine late genetic effects, and should therefore be carefully considered in the evaluation of risk for space missions.

  1. Current status of the radiation technology and quality control for radiation processing in Latin America

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Enrique Francisco Prietro, E-mail: efprieto@ceaden.edu.cu [Centro de Aplicaciones Tecnologicas y Desarrolo Nuclear (CEADEN), Habana (Cuba)

    2013-07-01

    The use of the radiation technology has gained acceptance in various regions of the world, where studies estimated that the installed capacity increases at a rate of 6 % per year and Latin America is part of this increase, due the advantages of this process when it is employed for the food preservation, sterilization of medical pharmaceutical material and to control the insect pests. This paper shows the art state of the application of Radiation Technology in Latin America, as well as the technological characteristics of the most gamma irradiation facilities and minor number the electron beam accelerator facilities, the types of irradiated products, state of the Quality Management System and the Dosimetric Systems used in the Radiation Processing Control in the Region. (author)

  2. Current status of the radiation technology and quality control for radiation processing in Latin America

    International Nuclear Information System (INIS)

    The use of the radiation technology has gained acceptance in various regions of the world, where studies estimated that the installed capacity increases at a rate of 6 % per year and Latin America is part of this increase, due the advantages of this process when it is employed for the food preservation, sterilization of medical pharmaceutical material and to control the insect pests. This paper shows the art state of the application of Radiation Technology in Latin America, as well as the technological characteristics of the most gamma irradiation facilities and minor number the electron beam accelerator facilities, the types of irradiated products, state of the Quality Management System and the Dosimetric Systems used in the Radiation Processing Control in the Region. (author)

  3. Radiation response of rodent neural precursor cells

    International Nuclear Information System (INIS)

    Full text: Therapeutic irradiation of the brain can cause cognitive dysfunction that is not treatable or well understood. Several lines of evidence from our laboratory suggest that radiation induced inhibition of neurogenesis in the hippocampus may be involved. To understand the mechanisms underlying these observations, we initiated studies using neural precursor cells isolated from the adult rat hippocampus. Cells were cultured exponentially and analyzed for acute (0-24h) and chronic (3-33 day) changes in apoptosis and oxidative stress following exposure to X-rays. Oxidative stress was measured using a dye sensitive to reactive oxygen species (ROS) and apoptosis was measured using annexin V binding; each endpoint was quantified by fluorescent automated cell sorting (FACS). Following exposure to X-rays, neural precursor cells exhibit a dose-responsive increase in the level of ROS and apoptosis over acute and chronic time frames. ROS and apoptosis were maximal at 12h, increasing 35 and 37% respectively over that of unirradiated controls. ROS and apoptosis peaked again at 24h, increasing 31 and 21% respectively over controls. Chronic levels of ROS and apoptosis were persistently elevated in a dose-dependent manner. ROS showed significant increases (34-180%) over a 3-4 week interval, while increases in apoptosis were less dramatic, rising 45% by week one before dropping to background. Irradiation of rat neural precursor cells was associated with an increase in p53 protein levels, and the activation of G1/S and G2/M checkpoints. These data suggest that the apoptotic and ROS responses may be tied to p53 dependent regulation of cell cycle control and stress activated pathways. We propose that oxidative stress plays a critical role in the radiation response of neural precursor cells, and discuss how this might contribute to the inhibition of neurogenesis and the cognitive impairment observed in the irradiated CNS

  4. Simple method to demonstrate radiation-inducible radiation resistance in microbial cells.

    OpenAIRE

    Tan, S. T.; Maxcy, R. B.

    1986-01-01

    A simple method for detection of radiation-inducible radiation resistance was developed by irradiating aliquots (0.01 ml) of cell suspension on agar plates. Part of each experimental plate was subjected to an induction treatment, and subsequent radiation resistance was compared with that of untreated cells on the same plate. The UV radiation resistance of a Micrococcus sp. was increased approximately 1.6 times by an induction treatment. This simple procedure of irradiating cells in a "fixed" ...

  5. Effect of ionizing radiation in the quality of exportable asparagus

    International Nuclear Information System (INIS)

    Due to the severe restriction which has been set upon the use of chemical fumigant by the importing countries of our horticulture products it has been studied the use of ionizing radiation in asparagus as an alternative treatment for quarantine restriction. The used are 0,15; 0,5; 1.0 y 2.0 kGy. Argenteuil and UC-157 varieties were used. The harvest, handing and storage conditions were the same as the ones export companies use. Both varieties were studied by the following quality parameters: pH, acidity, moisture, soluble solids, vitamin C, fibre content, dissecation, seeding and spreading, shooting, spear lengh, weight loss, microbial and moulds contamination, cutting resistance, respiratory rate, color and sensorial evaluation. From the result obtained it is possible to conclude that the irradiation did not produce deleterous effects on chemical, microbiological or organoleptic parameters in both varieties. From the point of view of the market quality the ionizing radiation could be used as a quarantine treatment under the normal marketing conditions used in Chile. Dose of 2.0 kGy does not produce a shelf life extention. (author)

  6. Radiation dose in cardiac CT angiography: Protocols and image quality

    International Nuclear Information System (INIS)

    This paper aims to evaluate the radiation dose exposure of patients submitted to cardiac computed tomography angiography. The effective dose was obtained from the product of dose-length product values and the conversion factor established in the European Working Group for Guidelines on Quality Criteria in CT. The image noise and contrast-and signal-to-noise ratios were obtained for all images. Sixty-four- and 256-slice CT angiographies were used in 211 (68.5 %) and 97 (31.5 %) patients, respectively. The calculated mean effective dose with prospective CT angiography was 6.0±1.0 mSv and the retrospective mode was 8.4±1.2 mSv. The mean image noise values were 38.5±9.5 and 21.4±5.3 for prospective and retrospective modes, respectively. It was observed that the image noise increased by 44.4 % using a prospective mode. Prospective CT angiography reduces radiation dose by ∼29 % compared with the retrospective mode, while maintaining diagnostic image quality and the ability to assess obstructions in patients. (authors)

  7. Strategies for quality assurance of intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    In late 2011 The Swedish Society of Radiation Physics formed a working group to concentrate on the Quality Assurance of modern radiation therapy techniques. The given task was to identify and summarise the different QA strategies in Sweden and also the international recommendations. This was used to formulate recommendations for practical guidelines within Sweden. In this paper a brief summery of the group's work is presented. All the Swedish radiation therapy centres do a pre treatment verification measurement as QA for every new IMRT and VMAT plan. Physicists do it and they believe it to be time consuming. A general standpoint from all the centres was that new guidelines and legislation is needed to allow QA that does not require a measurement. Based on various international publications and recommendations the working group has presented two strategies, one where all new plans are checked through measurement and one where no measurement is needed. The measurement- based strategy is basically the same as the one used today with an extended machine QA part. The other presented strategy is process oriented where all the different parts of the treatment chain are checked separately. The final report can be found in Swedish on http://www.radiofysik.org

  8. Correlation between image quality and radiation dose on screening mammography

    International Nuclear Information System (INIS)

    Objective: To obtain the matched parameters between image quality and radiation dose by exploring the influence of the exposure parameters of screening mammography on both the image quality and radiation dose. Methods: The correlation between the exposure parameters and average glandular doses to 507 patients undergoing screening mammography were retrospectively analyzed. The influence of breast compression thickness on radiation dose by exposing different thickness of PMMA was obtained. The correlation with image quality was analyzed by combined testing of contrast detail test mode (CDMAM3.4) and different thickness of PMMAs. Results: The groups aged 30 to 49 years were the main groups in 507 examined patients, up to 67.06% of the total. The mean value of average gland doses (AGD) in contrast-prior mode was the highest in three kinds of exposure modes,accounting for 137.5% of standard mode.In standard mode, target material/filtration board combination was Mo/Mo, Mo/Rh and Rh/Rh, accounting for 1/3 respectively. Mo/Rh and Rh/Rh were selected in dose-prior mode,accounting for 50% respectively. Mo/Mo was mainly selected in contrast-prior,accounting for 52%. Breast compression thickness was positively correlated with average gland doses. Image quality figure inverse (IQFinv) under three kinds of modes (STD, DOSE, CNT) was 98.32, 95.41 and 107.02, respectively, and IQFinv of contrast-prior mode was the highest among them. IQFinv was in general agreement in the three kinds of exposure modes when the thickness of PMMA plates plates was greater than or equal to 5 cm. Conclusions: In clinical practice, when the breast is of density type and pressed thickness is less than 4 em, the dose-prior mode should be selected. When the pressed thickness is between 4 and 6 cm, the standard exposure mode should be selected. When the pressed thickness is larger than 6 cm, the manual mode should be selected. (authors)

  9. Chemical modification of neoplastic cell transformation by heavy ion radiation

    International Nuclear Information System (INIS)

    Quantitative data on chemical modification of neoplastic cell transformation by heavy-ion radiation was obtained using in-vitro cell transformation technique. The specific aims were 1) to test the potential effects of various chemicals on the expression of cell transformation, and 2) to systematically collect information on the mechanisms of expression and progression of cell transformation by ionizing radiation. Recent experimental studies with DMSO, 5-azacytidine, and dexamethasone suggest that DMSO can effectively suppress the neoplastic cell transformation by high-LET radiation and that some nonmutagenic changes in DNA may be important in modifying the expression, and progression of radiation-induced cell transformation

  10. Investigation of solar cell radiation damage

    International Nuclear Information System (INIS)

    Development of communications satellites has led to the requirement for a greater and longer lived solar cell power source. Accordingly, studies have been undertaken with the aim of determining which solar cell array provides the greatest power at end of life and the amount of degradation. Investigation of the damage done to thin silicon and thin film CdS solar cells is being carried out in two steps. First, irradiations were performed singly with 0.15, 1.0 and 2.0MeV electrons and 0.7, 2.5 and 22MeV proton. Solar cells and their cover materials were irradiated separately in order to locate the sites of the damage. Diffusion length and I.V. characteristics of the cells and transmission properties of the cover materials were measured. All neasurements were made in vacuum immediately after irradiation. In the second part it is intended to study the effect of various combinations of proton, electron and photon irradiation both with and without an electrical load. The results of this part show whether synergism is involved in solar cell damage and the relative importance of each of three radiation sources if synergism is found

  11. Tumourigenicity and radiation resistance of mesenchymal stem cells

    DEFF Research Database (Denmark)

    D'Andrea, Filippo Peder; Horsman, Michael Robert; Kassem, Moustapha;

    2012-01-01

    Background. Cancer stem cells are believed to be more radiation resistant than differentiated tumour cells of the same origin. It is not known, however, whether normal nontransformed adult stem cells share the same radioresistance as their cancerous counterpart. Material and methods....... Nontumourigenic (TERT4) and tumourigenic (TRET20) cell lines, from an immortalised mesenchymal stem cell line, were grown in culture prior to irradiation and gene expression analysis. Radiation resistance was measured using a clonogenic assay. Differences in gene expression between the two cell lines, both under...... intercellular matrix. These results also indicate that cancer stem cells are more radiation resistant than stem cells of the same origin....

  12. Development of quality assurance procedures for production of sealed radiation source

    CERN Document Server

    Nam, J H; Cho, W K; Han, H S; Hong, S B; Kim, K H; Kim, S D; Lee, Y G; Lim, N J

    2001-01-01

    The quality assurance procedures for sealed radiation sources production using HANARO and RIPF have been developed. The detailed quality assurance procedures are essential to manage the whole work process effectively and ensure the quality of the produced sealed sources. Through applying this quality assurance procedures to the entire production works of the sealed radiation sources, it is expected that the quality of the products, the safety of the works and the satisfaction of the customers will be increased.

  13. Radiation quality of photons in small and large receptors - A Micro-dosimetric analysis

    International Nuclear Information System (INIS)

    The quality of different photon radiations in small and large receptors is assessed in terms of Micro-dosimetry. Monte Carlo simulations are performed for the electrons released by photons. To represent the case of a small receptor, only electrons released by the non-degraded incident photons are tracked. For a large receptor, all electrons released in the complete degradation process are followed. Dose averaged values, yD, of the lineal energy are derived from the simulated tracks for monoenergetic photons from 10 keV to 2 MeV. In Micro-dosimetry, the dose mean lineal energy is the major parameter of radiation quality. The results demonstrate distinct differences in radiation quality between high-energy gamma rays and conventional X-rays that are present not just in small cell samples but also in large receptors, such as the human body. The values of yD suggest that, for both small and large receptors, conventional X-rays should be about twice as effective as gamma rays from 60Co. (authors)

  14. Modeling the biological effectiveness of radiations of different qualities: Lethal damage induced by low-energy protons in V79 cells and correlations with energy deposition, radical distribution, and specific DNA damage

    Czech Academy of Sciences Publication Activity Database

    Kundrát, Pavel; Davídková, Marie; Štěpán, Václav; Palajová, Zdenka; Judas, Libor

    Heidelberg : IRPA, 2007, s. 51-51. ISBN 978-3-8249-1071-7. ISSN 1013-4506. [Workshop of Heavy CHarged Particles in Biology and Medicine /11./. Heidelberg (DE), 26.09.2007-29.09.2007] R&D Projects: GA ČR GA202/05/2728; GA ČR(CZ) GD202/05/H031 Institutional research plan: CEZ:AV0Z10480505; CEZ:AV0Z10100502 Keywords : biophysical modeling * V79 cells * lethal radiation damage Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  15. Radiation dose and image quality for paediatric interventional cardiology

    International Nuclear Information System (INIS)

    Radiation dose and image quality for paediatric protocols in a biplane x-ray system used for interventional cardiology have been evaluated. Entrance surface air kerma (ESAK) and image quality using a test object and polymethyl methacrylate (PMMA) phantoms have been measured for the typical paediatric patient thicknesses (4-20 cm of PMMA). Images from fluoroscopy (low, medium and high) and cine modes have been archived in digital imaging and communications in medicine (DICOM) format. Signal-to-noise ratio (SNR), figure of merit (FOM), contrast (CO), contrast-to-noise ratio (CNR) and high contrast spatial resolution (HCSR) have been computed from the images. Data on dose transferred to the DICOM header have been used to test the values of the dosimetric display at the interventional reference point. ESAK for fluoroscopy modes ranges from 0.15 to 36.60 μGy/frame when moving from 4 to 20 cm PMMA. For cine, these values range from 2.80 to 161.10 μGy/frame. SNR, FOM, CO, CNR and HCSR are improved for high fluoroscopy and cine modes and maintained roughly constant for the different thicknesses. Cumulative dose at the interventional reference point resulted 25-45% higher than the skin dose for the vertical C-arm (depending of the phantom thickness). ESAK and numerical image quality parameters allow the verification of the proper setting of the x-ray system. Knowing the increases in dose per frame when increasing phantom thicknesses together with the image quality parameters will help cardiologists in the good management of patient dose and allow them to select the best imaging acquisition mode during clinical procedures

  16. Radiation dose and image quality for paediatric interventional cardiology

    Energy Technology Data Exchange (ETDEWEB)

    Vano, E [Radiology Department, Medicine School, Complutense University and San Carlos University Hospital, 28040 Madrid (Spain); Ubeda, C [Clinical Sciences Department, Faculty of the Science of Health, Tarapaca University, 18 de Septiembre 2222, Arica (Chile); Leyton, F [Institute of Public Health of Chile, Marathon 1000, Nunoa, Santiago (Chile); Miranda, P [Hemodynamic Department, Cardiovascular Service, Luis Calvo Mackenna Hospital, Avenida Antonio Varas 360, Providencia, Santiago (Chile)], E-mail: eliseov@med.ucm.es

    2008-08-07

    Radiation dose and image quality for paediatric protocols in a biplane x-ray system used for interventional cardiology have been evaluated. Entrance surface air kerma (ESAK) and image quality using a test object and polymethyl methacrylate (PMMA) phantoms have been measured for the typical paediatric patient thicknesses (4-20 cm of PMMA). Images from fluoroscopy (low, medium and high) and cine modes have been archived in digital imaging and communications in medicine (DICOM) format. Signal-to-noise ratio (SNR), figure of merit (FOM), contrast (CO), contrast-to-noise ratio (CNR) and high contrast spatial resolution (HCSR) have been computed from the images. Data on dose transferred to the DICOM header have been used to test the values of the dosimetric display at the interventional reference point. ESAK for fluoroscopy modes ranges from 0.15 to 36.60 {mu}Gy/frame when moving from 4 to 20 cm PMMA. For cine, these values range from 2.80 to 161.10 {mu}Gy/frame. SNR, FOM, CO, CNR and HCSR are improved for high fluoroscopy and cine modes and maintained roughly constant for the different thicknesses. Cumulative dose at the interventional reference point resulted 25-45% higher than the skin dose for the vertical C-arm (depending of the phantom thickness). ESAK and numerical image quality parameters allow the verification of the proper setting of the x-ray system. Knowing the increases in dose per frame when increasing phantom thicknesses together with the image quality parameters will help cardiologists in the good management of patient dose and allow them to select the best imaging acquisition mode during clinical procedures.

  17. Cell/Tissue Culture Radiation Exposure Facility Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a Cell/Tissue Culture Radiation Exposure Facility (CTC-REF) to enable radiobiologists to investigate the real-time radiation effects on...

  18. Clinical implementation and quality assurance for intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    The paper describes the clinical implementation and quality assurance of intensity modulated radiation therapy (IMRT), based on experience at the Fox Chase Cancer Center, and reviews the procedures for the clinical implementation of the IMRT technique and the requirements for patient immobilization, target delineation, treatment optimization, beam delivery and system administration. The dosimetric requirements and measurement procedures for beam commissioning and dosimetry verification for IMRT are discussed and the details of model based dose calculation for IMRT treatment planning and the potential problems with such dose calculation algorithms are examined. The paper also discusses the effect of beam delivery systems on the actual dose distributions received by the patient and the methods to incorporate such effects in the treatment optimization process. Finally, the use of the Monte Carlo method for dose calculation and treatment verification for IMRT is investigated. (author)

  19. Clinical implementation and quality assurance for intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    This paper describes the clinical implementation and quality assurance (QA) for intensity-modulated radiation therapy (IMRT) based on the experience at Fox Chase Cancer Center, Philadelphia, USA. We will review our procedures for the clinical implementation of the IMRT technique and the requirements for patient immobilization, target delineation, treatment optimization, beam delivery and system administration. We will discuss the dosimetric requirements and measurement procedures for beam commissioning and dosimetry verification for IMRT. We will examine the details of model-based dose calculation for IMRT treatment planning and the potential problems with such dose calculation algorithms. We will discuss the effect of beam delivery systems on the actual dose distributions received by the patients and the methods to incorporate such effects in the treatment optimization process. We will investigate the use of the Monte Carlo method for dose calculation and treatment verification for IMRT

  20. Optimization of image quality and radiation dose in neuroradiological computed tomography

    OpenAIRE

    Löve, Askell

    2013-01-01

    Background: The goal of clinical computed tomography (CT) is to produce images of diagnostic quality using the lowest possible radiation exposure. Degradation of image quality, with increased image noise and reduced spatial resolution, is a major limitation for radiation dose reduction in CT. This can be counteracted with new post-processing image filters and iterative reconstruction (IR) algorithms that improve image quality and allow for reduced radiation doses. Implementation of new method...

  1. Nanodosimetric descriptors of the radiation quality of carbon ions

    International Nuclear Information System (INIS)

    In view of the emerging interest of carbon ions in radiotherapy and of the strong correlation between the track structure and the radiobiological effectiveness of ionising radiations, the track-structure properties of 12C-ions were studied at particle energies close to the Bragg peak. To perform the investigations, ionisation-cluster-size distributions for nanometre-sized target volumes were measured with the track-nano-dosimeter installed at the TANDEM-ALPI accelerator complex at LNL, and calculated using a dedicated Monte Carlo simulation code. The resulting cluster-size distributions are used to derive particular descriptors of particle track structure. Here, the main emphasis is laid on the mean ionisation-cluster size M1 and the cumulative probability Fk of measuring cluster sizes ν≥k. From the radiobiological point of view, Fk is of particular interest because an increasing k corresponds to an increase of damages of higher complexity. In addition, Fk saturates with increasing radiation quality like radiobiological cross sections as a function of linear energy transfer. Results will be presented and discussed for 12C-ions at 96 and 240 MeV. (authors)

  2. Objective assessment of image quality VI: imaging in radiation therapy

    International Nuclear Information System (INIS)

    Earlier work on objective assessment of image quality (OAIQ) focused largely on estimation or classification tasks in which the desired outcome of imaging is accurate diagnosis. This paper develops a general framework for assessing imaging quality on the basis of therapeutic outcomes rather than diagnostic performance. By analogy to receiver operating characteristic (ROC) curves and their variants as used in diagnostic OAIQ, the method proposed here utilizes the therapy operating characteristic or TOC curves, which are plots of the probability of tumor control versus the probability of normal-tissue complications as the overall dose level of a radiotherapy treatment is varied. The proposed figure of merit is the area under the TOC curve, denoted AUTOC. This paper reviews an earlier exposition of the theory of TOC and AUTOC, which was specific to the assessment of image-segmentation algorithms, and extends it to other applications of imaging in external-beam radiation treatment as well as in treatment with internal radioactive sources. For each application, a methodology for computing the TOC is presented. A key difference between ROC and TOC is that the latter can be defined for a single patient rather than a population of patients. (paper)

  3. Radiation safety and quality control in the cyclotron laboratory

    International Nuclear Information System (INIS)

    Radiation safety was determined to maintain quality control in the cyclotron laboratory. Based on the results of 438 runs in the Faraday cup (20 μA for 10 min), 20 runs on 18O-water target (40 μA for 2 h) and 10 runs on 18O-gas targets (30 μA for 45 min), we have established that occupationally exposed workers remain 10 ± 5 times below federal regulatory limits (FRLs) in the cyclotron vault, 30 ± 8 times below FRL in the radiochemistry laboratory and 200 ± 10 times below the FRL outside the cyclotron laboratory during beam operation. (The FRL for unrestricted area are <20 μSv in 1 h.) The non-occupationally exposed workers serving in offices in the vicinity of the cyclotron vault within 100 m distance remained 200 times below the FRL irrespective of beam being on or off, suggesting that routine beam operation of 40 μA for 2 h once a day during office hours is safe provided quality control and system performance measures as discussed in this report are strictly maintained. (authors)

  4. Cone beam computed tomography radiation dose and image quality assessments.

    Science.gov (United States)

    Lofthag-Hansen, Sara

    2010-01-01

    Diagnostic radiology has undergone profound changes in the last 30 years. New technologies are available to the dental field, cone beam computed tomography (CBCT) as one of the most important. CBCT is a catch-all term for a technology comprising a variety of machines differing in many respects: patient positioning, volume size (FOV), radiation quality, image capturing and reconstruction, image resolution and radiation dose. When new technology is introduced one must make sure that diagnostic accuracy is better or at least as good as the one it can be expected to replace. The CBCT brand tested was two versions of Accuitomo (Morita, Japan): 3D Accuitomo with an image intensifier as detector, FOV 3 cm x 4 cm and 3D Accuitomo FPD with a flat panel detector, FOVs 4 cm x 4 cm and 6 cm x 6 cm. The 3D Accuitomo was compared with intra-oral radiography for endodontic diagnosis in 35 patients with 46 teeth analyzed, of which 41 were endodontically treated. Three observers assessed the images by consensus. The result showed that CBCT imaging was superior with a higher number of teeth diagnosed with periapical lesions (42 vs 32 teeth). When evaluating 3D Accuitomo examinations in the posterior mandible in 30 patients, visibility of marginal bone crest and mandibular canal, important anatomic structures for implant planning, was high with good observer agreement among seven observers. Radiographic techniques have to be evaluated concerning radiation dose, which requires well-defined and easy-to-use methods. Two methods: CT dose index (CTDI), prevailing method for CT units, and dose-area product (DAP) were evaluated for calculating effective dose (E) for both units. An asymmetric dose distribution was revealed when a clinical situation was simulated. Hence, the CTDI method was not applicable for these units with small FOVs. Based on DAP values from 90 patient examinations effective dose was estimated for three diagnostic tasks: implant planning in posterior mandible and

  5. Simple method to demonstrate radiation-inducible radiation resistance in microbial cells

    International Nuclear Information System (INIS)

    A simple method for detection of radiation-inducible radiation resistance was developed by irradiating aliquots (0.01 ml) of cell suspension on agar plates. Part of each experimental plate was subjected to an induction treatment, and subsequent radiation resistance was compared with that of untreated cells on the same plate. The UV radiation resistance of a Micrococcus sp. was increased approximately 1.6 times by an induction treatment. This simple procedure of irradiating cells in a fixed position on agar avoided washing, centrifugation, and cell enumeration required in traditional methods

  6. The concept of radiation-enhanced stem cell differentiation

    International Nuclear Information System (INIS)

    Efficient stem cell differentiation is considered to be the holy grail of regenerative medicine. Pursuing the most productive method of directed differentiation has been the subject of numerous studies, resulting in the development of many effective protocols. However, the necessity for further improvement in differentiation efficiency remains. This review contains a description of molecular processes underlying the response of stem cells to ionizing radiation, indicating its potential application in differentiation procedures. In the first part, the radiation-induced damage response in various types of stem cells is described. Second, the role of the p53 protein in embryonic and adult stem cells is highlighted. Last, the hypothesis on the mitochondrial involvement in stem cell development including its response to ionizing radiation is presented. In summary, despite the many threats of ionizing radiation concerning genomic instability, subjecting cells to the appropriate dosage of ionizing radiation may become a useful method for enhancing directed differentiation in certain stem cell types

  7. Stem Cell Therapy Remediates Reconstruction of the Craniofacial Skeleton After Radiation Therapy

    OpenAIRE

    Deshpande, Sagar S.; Gallagher, Kathleen K.; Donneys, Alexis; Tchanque-Fossuo, Catherine N.; Sarhaddi, Deniz; Sun, Hongli; Krebsbach, Paul H; Buchman, Steven R.

    2013-01-01

    This study utilized transplanted bone marrow stromal cells (BMSCs) as a cellular replacement therapy to remedy radiation-induced injury and restore impaired new bone formation during distraction osteogenesis (DO). BMSC therapy brought about the successful generation of new bone and significantly improved both the rate and quality of a bony union of irradiated, distracted [X-ray radiation therapy (XRT)/DO] murine mandibles to the level of nonirradiated DO animals. The bone mineral density and ...

  8. Discussion on the compilation of document of iso quality management system for radiation sterilization enterprises

    International Nuclear Information System (INIS)

    According to the character of cooperation of radiation sterilization, and association with request of ISO9001, ISO13485 and ISO11137, compilation of document in quality manual, procedure document and technological document during certification of ISO quality management system of cooperation of radiation sterilization was discussed. (authors)

  9. Quality assurance of radiation monitoring performed of the swedish nuclear industry. Discharges of liquid wastes 1989

    International Nuclear Information System (INIS)

    The swedish nuclear power plants have own administration of some radiation monitoring. These monitoring programs are quality controlled by the Swedish Radiation Protection Institute (SSI). The report presents the results of the quality control 1989. The following were controlled: Interlaboratory comparisons of Sr-90 measurements discharge of liquid wastes 1989. Discharge of plutonium 1988

  10. Quality assurance of radiation monitoring performed by the Swedish nuclear industry. Discharges of liquid wastes 1991

    International Nuclear Information System (INIS)

    The Swedish nuclear power plants have their own administration of some radiation monitoring. These monitoring programs are quality controlled by the Swedish Radiation Protection Institute (SSI). The report presents the results of the quality control 1991. The following were controlled; interlaboratory comparisons 1991, discharges of liquid wastes 1991

  11. Quality assurance of radiation monitoring performed at the swedish nuclear industry. Discharge of liquid wastes 1990

    International Nuclear Information System (INIS)

    The swedish nuclear power plants have own administration of some radiation monitoring. These monitoring programs are quality controlled by the Swedish Radiation Protection Institute (SSI). The report presents the results of the quality control 1990. The following were controlled: Interlaboratory comparisons of measurements of gamma emitting nuclides in water. Discharge of liquid wastes. Discharge of plutonium

  12. Radiation-induced apoptosis in microvascular endothelial cells.

    OpenAIRE

    Langley, R. E.; Bump, E A; Quartuccio, S. G.; Medeiros, D.; Braunhut, S. J.

    1997-01-01

    The response of the microvasculature to ionizing radiation is thought to be an important factor in the overall response of both normal tissues and tumours. It has recently been reported that basic fibroblast growth factor (bFGF), a potent mitogen for endothelial cells, protects large vessel endothelial cells from radiation-induced apoptosis in vitro. Microvessel cells are phenotypically distinct from large vessel cells. We studied the apoptotic response of confluent monolayers of capillary en...

  13. The influence of scattered radiation on recording systems and quality-assurance test parameters

    International Nuclear Information System (INIS)

    Scattered radiation generated in patient and imaging system has to be considered when quality-assurance tests involve dose detection or image-quality estimations. Measurement of automatic-exposure control dose can be altered by backscattering from intensifying screens of more than 10% and the equipment transmission factor can be overestimated up to a factor of 10 when only primary radiation is used. The sensitivity of intensifying screens depends on the angle of incidence of the radiation and so primary and scattered radiation are detected differently. The quality-control aspects of anti-scatter grids are discussed. (author)

  14. Influence of yeast cell ploidy on relative biological effectiveness of densely ionizing radiation

    International Nuclear Information System (INIS)

    A study was made of radiosensitivity of haploid and diploid yeast Saccharomyces cerevisiae and Pichia pinus exposed to γ- quanta (137Cs) and α-rays (239Pu). On the basis of the experimental data obained a theoretical formula was deduced correla. ting RBE of radiation of different quality for haploid and diploid cells

  15. Enhancing reproductive potential and quality of graspea through gamma radiation

    International Nuclear Information System (INIS)

    Two grasspea genotypes Nirmal and P-24 were treated with 10, 20 and 30 kR y ray. In Mt germination was highly reduced and pollen fertility declined progressively with the gradual increase of y doses. In M2 both the genotypes displayed maximum reduction in pod number and seed yield in 30 kR dose. At lower dose seed yield recorded an increase. For pods/plant and seed yield/plant superior lines were selected and from the superior lines promising individuals were identified inMr Low dose of y ray induced major shift in mean with high frequency suggesting the occurrence of families of higher pod production and improved seed yield potential. Several superior individuals were identified lii M} from either 10 kR or 20 kR treated population. Two individuals derived from 1 OkR of P-24 and 20 kR treated Nirmal appeared most outstanding. They recorded significant decline in BOAA but alleviated level of albumin protein fraction with increased seed yield. The low dose of y radiation would thus likely to throw useful and desirable mutants with high seed yield potentiality and improved seed quality in grasspea genotypes

  16. Radiation damage and repair in cells and cell components. Part 2. Physical radiations and biological significance. Final report

    International Nuclear Information System (INIS)

    The report comprises a teaching text, encompassing all physical radiations likely to be of biological interest, and the relevant biological effects and their significance. Topics include human radiobiology, delayed effects, radiation absorption in organisms, aqueous radiation chemistry, cell radiobiology, mutagenesis, and photobiology

  17. Epigenetic cell response to an influence of ionizing radiation

    International Nuclear Information System (INIS)

    Importance of radiation modification of epigenetic activity in the general mechanism of radiobiological reactions is proved. Inheritable epigenetic changes induced by irradiation are one of the basic reasons of formation of the remote radiation pathology. It is noted that epigenetic inheritable changes of cells have the determined character distinguishing them mutation changes, being individual and not directed. It is underlined the ability of ionizing radiation to modify level of spontaneous genetic instability inherited in a number of cell generations on epigenetic mechanism

  18. Space solar cells - High efficiency and radiation damage

    Science.gov (United States)

    Brandhorst, H. W., Jr.; Bernatowicz, D. T.

    1980-01-01

    The proceedings of the Third Solar Cell High Efficiency and Radiation Damage Meeting are outlined. The topics covered included high efficiency silicon solar cells, silicon solar cell radiation damage, GaAs solar cell performance, and 30 percent conversion devices. The study of radiation damage from a fundamental defect-centered basis is discussed and evaluated as a focus of future work. 18% AM0 efficiency and 0.7 V open-circuit voltages are designated as achievable goals for silicon solar cells, and the potential for 30% AM0 efficiencies from monolithic tandem cell designs without sunlight concentration is noted. In addition to its potential for 20% AM0 efficiencies, the GaAs cell offers the possibility of a radiation-insensitive power supply when operated at temperatures near 200 C.

  19. Verification of light & radiation field coincidence quality assurance for radiation therapy by using a-Se based DR system

    Science.gov (United States)

    Kim, Jin-Young; Park, Eun-Tae; Choi, Yun-Seon; Cho, Heung-Lae; Ahn, Ki-Jung; Park, Sung-Kwang; Kim, Ji-Na; Suh, Tae-Suk; Kim, Jin-Seon; Hong, Ju-Yeon; Park, Jeong-Eun; Kim, Kyo-Tae; Oh, Kyung-Min; Kim, Hyunjung; Jo, Sun-Mi; Oh, Won-Yong; Jin, Seong-Jin; Cho, Woong

    2015-04-01

    Currently, the American Association of Physicists in Medicine (AAPM) recommends measuring the surface field size once a week by using an analog film in order to verify light and radiation field coincidence in the Quality Assurance (QA) of radiotherapy. However, the use of the film does not allow for a quantitative method of evaluation, and measuring the light field with radiation field detectors in a 2D array is difficult. Therefore, we used an amorphous-Se (a-Se) digital radiation detection system to measure the light and radiation fields simultaneously for a quantitative QA system, and the feasibility of using such a system was confirmed by ensuring the coincidence of the light and the radiation field measurements. The characteristics of the analog film and the a-Se digital radiation detection system were compared by delivering to each doses of 100, 10 monitor units(MU) of radiation at a rate of 400 MU/min to a radiation field 100 × 100 mm2 in size from a 100 cm source-surface distance (SSD). A 0.5 mm to 0.6 mm difference was measured in the X-axis, and a 0.3 mm difference was measured in the Y-axis. The difference in the measurements of the coincidence of light and the radiation field was less than 0.3 mm, which is relatively insignificant. These results indicate that the use of an a-Se digital radiation detection system is adequate for quality assurance of radiotherapy using light and radiation field coincidence. In addition, the experiment is considered to have provided valuable results in that the a-Se based digital radiation detection system enables simple and accurate QA for clinical radiation therapy by assessing the coincidence in the alignment of the light and the radiation fields.

  20. Altruistic cell suicide in relation to radiation hormesis

    International Nuclear Information System (INIS)

    The high radiosensitivity to killing of undifferentiated primordial cells (Bergonie and Tribondeau 1906) can be described as a manifestation of the suicide of injured cells for the benefit of an organism as a whole if their suicide stimulates proliferation of healthy cells to replace them, resulting in complete elimination of injury. This process is called cell-replacement repair, to distinguish it from DNA repair which is rarely complete. 'Cell suicide', 'programmed death' and 'apoptosis' are terms used for the same type of active cell death. Cell suicide is not always altruistic. Altruistic suicide in Drosophila, mice, humans, plants, and E. coli is reviewed in this paper to illustrate its widely different facets. The hypothesis that in animals, radiation hormesis results from altruistic cell suicide is proposed. This hypothesis can explain the hormetic effect of low doses of radiation on the immune system in mice. In contrast, in plants, radiation hormesis seems to be mainly due to non-altruistic cell death. (author)

  1. Effects of radiation and chemical substances on cells and organism

    International Nuclear Information System (INIS)

    The book treats the radiation chemistry part of biophysics and applied biophysics in the sphere of ionizing radiation. Discussed are the concepts of radiation units and radioactivity units and the relative biological efficiency. The effects of ionizing and UV radiations are analyzed at the level of macromolecular changes. Chapters dealing with genetic radiation effects discuss the effects at the cellular level with respect to cell proliferation. All these problems are used to illustrate the effect on the organism as a whole. The chapters on applied biophysics deal with the indications of radiation and chemical damage, sensitivity of cells and the organism, and the study and influencing of growth at the cellular level. The concluding chapter is devoted to the environmental impact of radiation. (J.P.)

  2. Low- and high-LET radiation drives clonal expansion of lung progenitor cells in vivo.

    Science.gov (United States)

    Farin, Alicia M; Manzo, Nicholas D; Kirsch, David G; Stripp, Barry R

    2015-01-01

    Abundant populations of epithelial progenitor cells maintain the epithelium along the proximal-to-distal axis of the airway. Exposure of lung tissue to ionizing radiation leads to tissue remodeling and potential cancer initiation or progression. However, little is known about the effects of ionizing radiation on airway epithelial progenitor cells. We hypothesized that ionizing radiation exposure will alter the behavior of airway epithelial progenitor cells in a radiation dose- and quality-dependent manner. To address this hypothesis, we cultured primary airway epithelial cells isolated from mice exposed to various doses of 320 kVp X ray or 600 MeV/nucleon (56)Fe ions in a 3D epithelial-fibroblast co-culture system. Colony-forming efficiency of the airway epithelial progenitor cells was assessed at culture day 14. In vivo clonogenic and proliferative potentials of airway epithelial progenitor cells were measured after exposure to ionizing radiation by lineage tracing and IdU incorporation. Exposure to both X rays and (56)Fe resulted in a dose-dependent decrease in the ability of epithelial progenitors to form colonies in vitro. In vivo evidence for increased clonogenic expansion of epithelial progenitors was observed after exposure to both X rays and (56)Fe. Interestingly, we found no significant increase in the epithelial proliferative index, indicating that ionizing radiation does not promote increased turnover of the airway epithelium. Therefore, we propose a model in which radiation induces a dose-dependent decrease in the pool of available progenitor cells, leaving fewer progenitors able to maintain the airway long-term. This work provides novel insights into the effects of ionizing radiation exposure on airway epithelial progenitor cell behavior. PMID:25564721

  3. Mesenchymal stem cell therapy for acute radiation syndrome.

    Science.gov (United States)

    Fukumoto, Risaku

    2016-01-01

    Acute radiation syndrome affects military personnel and civilians following the uncontrolled dispersal of radiation, such as that caused by detonation of nuclear devices and inappropriate medical treatments. Therefore, there is a growing need for medical interventions that facilitate the improved recovery of victims and patients. One promising approach may be cell therapy, which, when appropriately implemented, may facilitate recovery from whole body injuries. This editorial highlights the current knowledge regarding the use of mesenchymal stem cells for the treatment of acute radiation syndrome, the benefits and limitations of which are under investigation. Establishing successful therapies for acute radiation syndrome may require using such a therapeutic approach in addition to conventional approaches. PMID:27182446

  4. X radiation qualities characterization following the standard IEC 61267 recommendations at the calibration laboratory of IPEN

    International Nuclear Information System (INIS)

    This work presents a methodology for the X radiation qualities characterization following the new recommendations of the standard 61267 of the International Electrotechnical Commission (IEC) to establish a new procedure for calibration of dosimetric systems used in the field of diagnostic radiology. The reference qualities radiation of IEC 61267: RQR 2 to RQR 10, RQA 2 to RQA 10, RQB 2 to RQB 10 and RQN 2 to RQN 10 were implanted at the calibration laboratory of IPEN (LCI). Their characteristics were analyzed through measurements of beam parameters such as: Practical peak voltage (PPV), specific additional filtrations for each qualities (high purity aluminum of about 99.9%), 1st and 2nd Half Value Layers, homogeneity coefficient. The inherent filtration of the X ray tube was also determined. With the establishment of these radiation qualities, the LCI will be ready to calibrate the measuring instruments of radiation in the new qualities, allowing an improvement in radiological services offered by IPEN. (author)

  5. Radiation safety and quality in diagnostic x-ray imaging 2001

    International Nuclear Information System (INIS)

    The obligations of the medical exposure directive (97/43/Euratom) for hospitals dominate the current activities in radiation protection in medical radiology. The directive gives special emphasis to radiation exposure of children, to examinations with high radiation doses and to radiation exposure in health screening programmes. The most important examinations with high doses are radiological interventions, where even acute skin effects are possible, and the computed tomography where the number of CT examinations makes only about 5% from the total number of x-ray examinations but the collective effective dose about 40% from the combined collective effective dose of all x-ray examinations. In the research projects financed by the European Commission, radiation exposures to paediatric patients have been measured in radiography, fluoroscopy and CT, and various dose assessment methods have been compared to develop a method for national follow-up of patients' radiation dose. The newest research project is focused on dosimetry and quality assurance in interventional radiology and digital imaging. Other actual topics are the development of radiation protection regulations and quality systems, education and training programmes, and clinical audits. This report deals with new radiation protection guides and recommendations and the education and training of radiological staff in radiation protection. One important topic is the development of national follow-up method of radiation exposure to patients and comparison of various dose assessment methods. Quality assurance in health care and in paediatric radiology, and the acceptance test and quality assurance measurements of radiological equipment are also described. (orig.)

  6. The benefit of treatment intensification is age and histology-dependent in patients with locally advanced non-small cell lung cancer (NSCLC): a quality-adjusted survival analysis of radiation therapy oncology group (RTOG) chemoradiation studies

    International Nuclear Information System (INIS)

    Purpose: Currently, chemoradiation treatment strategies in locally advanced NSCLC are essentially the same irrespective of tumor histology or patient age. The purpose of this study is to analyze the impact of age, histology, Karnofsky performance status (KPS), and specific toxicities on the median survival time (MST) and quality-adjusted survival (QTime) for each treatment strategy. Methods and Materials: Nine hundred seventy-nine patients with Stage II-IIIB inoperable NSCLC were enrolled on 6 prospective Phase II and III studies from 1983 to 1995. Treatment regimens ranged from standard RT (SRT) to 60 Gy, hyperfractionated RT (HRT) to 69.6 Gy, induction chemotherapy (ICT) of cisplatin (CIS) and vinblastine (VBL) followed by SRT, ICT + concurrent CT (CCT) + SRT, and CCT + HRT; CCT consisted of etoposide or VBL + CIS. Toxicities assessed were skin, mucous membrane, lung, esophagus, neurologic, hematologic, and upper GI. QTime was calculated by weighting the time spent with a specific toxicity, as well as local or distant tumor progression. Each toxicity was weighted with increasing severity as the toxicity increased in grade. Results: As expected, patients with the worst KPS (50-70) had the lowest MST (7.8 months) and QTime (6.7 months). Patients 70 years achieved the best QTime with standard RT (SRT) alone. In patients with squamous cell carcinoma, those treated with ICT + CCT + SRT had dramatically improved MST (25.7 months) and QTime (21.8 months) compared to the other treatment regimens (11.7-12.8 and 10.7-12 months, respectively). Patients with adenocarcinoma, however, generally manifested incrementally better MST and QTime as the therapies intensified. Within the concurrent chemoradiation arms, the upper GI and lung toxicities had the greatest impact on QTime. Conclusion: This quality-adjusted survival analysis suggests that there is a critical relationship between the type of histology and its optimal treatment, age and the ability to tolerate intensive

  7. Epidermal stem cells response to radiative genotoxic stress

    International Nuclear Information System (INIS)

    Human skin is the first organ exposed to various environmental stresses, which requires the development by skin stem cells of specific mechanisms to protect themselves and to ensure tissue homeostasis. As stem cells are responsible for the maintenance of epidermis during individual lifetime, the preservation of genomic integrity in these cells is essential. My PhD aimed at exploring the mechanisms set up by epidermal stem cells in order to protect themselves from two genotoxic stresses, ionizing radiation (Gamma Rays) and ultraviolet radiation (UVB). To begin my PhD, I have taken part of the demonstration of protective mechanisms used by keratinocyte stem cells after ionizing radiation. It has been shown that these cells are able to rapidly repair most types of radiation-induced DNA damage. Furthermore, we demonstrated that this repair is activated by the fibroblast growth factor 2 (FGF2). In order to know if this protective mechanism is also operating in cutaneous carcinoma stem cells, we investigated the response to gamma Rays of carcinoma stem cells isolated from a human carcinoma cell line. As in normal keratinocyte stem cells, we demonstrated that cancer stem cells could rapidly repair radio-induced DNA damage. Furthermore, fibroblast growth factor 2 also mediates this repair, notably thanks to its nuclear isoforms. The second project of my PhD was to study human epidermal stem cells and progenitors responses to UVB radiation. Once cytometry and irradiation conditions were set up, the toxicity of UVB radiation has been evaluate in the primary cell model. We then characterized UVB photons effects on cell viability, proliferation and repair of DNA damage. This study allowed us to bring out that responses of stem cells and their progeny to UVB are different, notably at the level of part of their repair activity of DNA damage. Moreover, progenitors and stem cells transcriptomic responses after UVB irradiation have been study in order to analyze the global

  8. Radiation safety and quality assurance in diagnostic x-ray imaging 1999

    International Nuclear Information System (INIS)

    In the European Union, the Directive 97/43/Euratom concerning the medical use of radiation brings many new tasks to radiation users. Quality assurance, patient dose measurement, staff training and clinical audit are among the most essential of these tasks. The Finnish radiation legislation has been modified to comply with the Directive. Much work is still required for practical implementation of these rules. This report deals with applications of the medical radiation Directive. Most applications are still at the planning stage, and clear guidance is lacking. However, the users have to know in time about these plans and future duties concerning them. Experience on quality assurance and clinical audit in hospitals are especially valuable in providing practical information on benefits and problems of these practices. Other radiation related topics, such as radiation risks, radioactivity in foods, and use of radiation in other European countries, are also included in the report. (orig.)

  9. F-value as a chromosomal fingerprint of the quality of radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Masao S. [Kyoto Univ. (Japan). Radiation Biology Center

    1999-12-01

    Since the first proposal by Brenner and Sachs (Radiation Res. 140, 134-142, 1994), the F-value, the ratio of inter- to intra-chromosomal interchanges, as a biomarker for the quality of radiation has been a matter of repeated discussion. Controversies seem to stem from the selection of data which are heterogeneous in terms of chromosome scoring criteria and dose range. In the context of the critical evaluation of the validity of the F-value, the cytogenetic data obtained in our laboratory from the in vitro irradiation of human peripheral blood lymphocytes have been re-assessed for the F-value. The results were consistent with the original contention that the densely ionizing radiations showed lower F-value. The differential F-value was more pronounced in the low-dose range and disappeared with the increase of the dose, or more precisely with the number of charged particles passing through the cell nucleus. The range or charged particles also plays a role, which makes the F-value of neutrons insensitive to their energy due to a wide variation of the kinetic energy of recoil protons. (author)

  10. Prevention of radiation induced xerostomia and improved quality of life: Submandibular salivary gland transfer

    International Nuclear Information System (INIS)

    Over 60,000 new cases of head and neck cancers, and approximately 15,000 deaths occur every year in the United States (1). Head and neck cancers affect more men then women by a factor of 2:1, although the incidence of women is increasing as a result of increased tobacco use (2). Over 90% of all head and neck cancers are squamous cell carcinomas; most of the remaining cancers are adenocarcinomas. A combination of radiation therapy and surgery is used as the standard, primary treatment modality. Xerostomia occurs when the salivary glands are affected by irradiation. Patients experiencing xerostomia are at an increased risk for a wide variety of oral problems; all adversely affecting one's quality of life. Currently patients make lifestyle changes, dietary modifications, and use artificial salivas, sprays, gels, and lozenges to help mask their xerostomia. However, none of these products stimulate natural salivary production and act as a replacement therapy rather then a cure for xerostomia. A new protocol, RTOG 1083 has been approved by the Radiation Therapy Oncology Group, which involves a surgical transfer of a submandibular salivary gland to the submental space (where it can be easily shielded) as a method of prevention of radiation induced xerostomia. (author)

  11. Cell Processing Engineering for Regenerative Medicine : Noninvasive Cell Quality Estimation and Automatic Cell Processing.

    Science.gov (United States)

    Takagi, Mutsumi

    2016-01-01

    The cell processing engineering including automatic cell processing and noninvasive cell quality estimation of adherent mammalian cells for regenerative medicine was reviewed. Automatic cell processing necessary for the industrialization of regenerative medicine was introduced. The cell quality such as cell heterogeneity should be noninvasively estimated before transplantation to patient, because cultured cells are usually not homogeneous but heterogeneous and most protocols of regenerative medicine are autologous system. The differentiation level could be estimated by two-dimensional cell morphology analysis using a conventional phase-contrast microscope. The phase-shifting laser microscope (PLM) could determine laser phase shift at all pixel in a view, which is caused by the transmitted laser through cell, and might be more noninvasive and more useful than the atomic force microscope and digital holographic microscope. The noninvasive determination of the laser phase shift of a cell using a PLM was carried out to determine the three-dimensional cell morphology and estimate the cell cycle phase of each adhesive cell and the mean proliferation activity of a cell population. The noninvasive discrimination of cancer cells from normal cells by measuring the phase shift was performed based on the difference in cytoskeleton density. Chemical analysis of the culture supernatant was also useful to estimate the differentiation level of a cell population. A probe beam, an infrared beam, and Raman spectroscopy are useful for diagnosing the viability, apoptosis, and differentiation of each adhesive cell. PMID:25373455

  12. DNA repair and radiation sensitivity in mammalian cells

    International Nuclear Information System (INIS)

    Ionizing radiation induces various types of damage in mammalian cells including DNA single-strand breaks, DNA double-strand breaks (DSB), DNA-protein cross links, and altered DNA bases. Although human cells can repair many of these lesions there is little detailed knowledge of the nature of the genes and the encoded enzymes that control these repair processes. We report here on the cellular and genetic analyses of DNA double-strand break repair deficient mammalian cells. It has been well established that the DNA double-strand break is one of the major lesions induced by ionizing radiation. Utilizing rodent repair-deficient mutant, we have shown that the genes responsible for DNA double-strand break repair are also responsible for the cellular expression of radiation sensitivity. The molecular genetic analysis of DSB repair in rodent/human hybrid cells indicate that at least 6 different genes in mammalian cells are responsible for the repair of radiation-induced DNA double-strand breaks. Mapping and the prospect of cloning of human radiation repair genes are reviewed. Understanding the molecular and genetic basis of radiation sensitivity and DNA repair in man will provide a rational foundation to predict the individual risk associated with radiation exposure and to prevent radiation-induced genetic damage in the human population

  13. On the quality of treatment planning systems in radiation therapy

    International Nuclear Information System (INIS)

    Purpose: To assist in the design of quality assurance activities of 3D treatment planning systems (TPSs), a postal survey has been carried out, addressing TPS users on quality characteristics and their relative importance in clinical routine planning. Material and methods: The approach as described in ISO/IEC 9126 has been used to analyze TPS quality. Both TPS quality characteristics and how these may be used to establish a quality model are included. A questionnaire on ranking of these TPS quality characteristics has been sent out to the German DEGRO members in February 1997. Results: By the end of July 1997, 90 individual assessments (of 45 physicists, 35 physicians, and 10 radiographers) had been collected. On an importance scale from 1 (very important) to 6 (unimportant), weight factors of 1.71 (portability), 2.84 (maintainability), 3.18 (efficiency), 3.85 (usability), 4.52 (functionality) and 4.90 (reliability) have been determined from the data. From user satisfaction data also obtained from the questionnaire responses, baseline quality indices could be established from the quality model for the RTPs Cadplan, TMS Helax, and Voxelplan. Conclusion: The responses highlight the need for TPS quality assurance at the same time along the lines of safety-related, research-oriented, and interactive end-user software systems in radiotherapy treatment planning. Quality assurance activities must take this into account. Their effect can be monitored by using quality indices as derivable from the established quality model. (orig.)

  14. Implementation of quality assurance and quality control in the Nuclear Analytical Laboratory of the Estonian Radiation Protection Centre

    International Nuclear Information System (INIS)

    The Analytical Laboratory of the Estonian Radiation Protection Centre is in the process of implementing the system of Quality Assurance (QA) and Quality Control (QC) in the framework of the IAEA TC Project RER/2/004/ 'QA/QC of Nuclear Analytical Techniques'. The draft Quality Manual with annexes has been prepared accordingly to the ISO 17025 Guide, documents and other printed material delivered on the seminars of the project. The laboratory supply has been supplemented with necessary equipment for guaranteeing of quality. Proficiency testing included in the project has been performed successfully. (author)

  15. Effect of troglitazone on radiation sensitivity in cervix cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    An, Zheng Zhe; Liu, Xian Guang; Song, Hye Jin; Choi, Chi Hwan; Kim, Won Dong; Park, Woo Yoon [Chungbuk National University College of Medicine, Cheongju (Korea, Republic of); Yu, Jae Ran [Konkuk University College of Medicine, Chungju (Korea, Republic of)

    2012-06-15

    Troglitazone (TRO) is a peroxisome proliferator-activated receptor {gamma} (PPAR{gamma} ) agonist. TRO has antiproliferative activity on many kinds of cancer cells via G1 arrest. TRO also increases Cu{sup 2+}/Zn{sup 2+} -superoxide dismutase (CuZnSOD) and catalase. Cell cycle, and SOD and catalase may affect on radiation sensitivity. We investigated the effect of TRO on radiation sensitivity in cancer cells in vitro. Three human cervix cancer cell lines (HeLa, Me180, and SiHa) were used. The protein expressions of SOD and catalase, and catalase activities were measured at 2-10 {mu}M of TRO for 24 hours. Cell cycle was evaluated with flow cytometry. Reactive oxygen species (ROS) was measured using 2',7'-dichlorofluorescin diacetate. Cell survival by radiation was measured with clonogenic assay. By 5 {mu}M TRO for 24 hours, the mRNA, protein expression and activity of catalase were increased in all three cell lines. G0- G1 phase cells were increased in HeLa and Me180 by 5 {mu}M TRO for 24 hours, but those were not increased in SiHa. By pretreatment with 5 {mu}M TRO radiation sensitivity was increased in HeLa and Me180, but it was decreased in SiHa. In Me180, with 2 {mu}M TRO which increased catalase but not increased G0-G1 cells, radiosensitization was not observed. ROS produced by radiation was decreased with TRO. TRO increases radiation sensitivity through G0-G1 arrest or decreases radiation sensitivity through catalasemediated ROS scavenging according to TRO dose or cell types. The change of radiation sensitivity by combined with TRO is not dependent on the PPAR {gamma} expression level.

  16. Radiation induced mitochondrial biogenesis: limitations of metabolic viability based assays in measuring radiation induced cell death

    International Nuclear Information System (INIS)

    Many techniques based on metabolic viability of cells employing MTT and MTS assay are being widely used to measure the radiation and chemotherapeutics induced cell death, because of their high throughput capability. These assays are based on mitochondrial potential of cells to convert the substrate in to measurable products and remain dependent on this notion that all the cells untreated and treated will have equal mitochondrial content and metabolic potential. However, it is increasingly becoming clear that treatment induced changes in both mitochondrial content and metabolism can influence the metabolic viability of cells and radiation is a potential mitochondrial biogenesis inducer. Therefore, we tested if metabolic viability based assays are true measure of radiation induced cell death using the widely used cell lines like RAW264.7, HEK293, NIH3T3, J774.1, BMG-1, MDAMB231, MCF-7, A549 and HeLa. Cells were irradiated with gamma rays (60Co) and enumerated cell numbers (by hemocytometer) and metabolic viability using MTT assay at 24 and 48 hours after exposure. At all the absorbed doses (0-5 Gy), the extent of reduction in cell number was found to be larger than the decrease in formazan formation in all the cell lines tested. Further, this difference in the cell number and formazan formation varied significantly among the cell lines. To test if the increased formazan formation is due to increased mitochondrial content per cell, we analyzed the radiation induced mitochondrial biogenesis using mitochondria specific dye mitotracker red and found a 1.5 to 2 fold increase in mitochondrial content. These findings suggest that radiation induces mitochondrial biogenesis that enhances the metabolic potential leading to increased formazan formation. Therefore, conclusions drawn on radiation induced cytotoxicity based on metabolic viability assays are likely to be erroneous as it may not correlate with growth inhibition and/or loss of clonogenic survival. (author)

  17. Radiation-induced cerebral cell apoptosis in rats

    International Nuclear Information System (INIS)

    Objective: To study the influence of radiation on rat cerebral cells including neurons and gliocytes. Methods: The rats were divided into control group and X-ray radiation groups with different doses. The apoptosis of cells at different time points after radiation was observed by optic microscopy, electron microscopy and DNA agarose gel electrophoresis. The double label method (in situ end-labeling of DNA strand breaks for labeling apoptotic cells, and immunohistochemistry for labeling cell type) was used to label apoptotic neurons and gliocytes cells separately. Results: The distinct morphological features of apoptosis and the DNA fragmentation ladders on agarose gel electrophoresis were seen in radiation groups. The rate of apoptosis in the adult rat brain was low. There were many apoptotic glial cells (about 93%) and a few apoptotic neurons (about 5%) after radiation. The apoptotic rate in high dose group was higher than that in low dose group. Conclusion: Apoptosis can be induced by radiation in rat brain, the apoptotic rate increases with a increasing dose in the range of 2-8 Gy. The gliocytes are more sensitive to radiation-induced apoptosis than the neurons

  18. Environmental radiation control and quality management system in design and operation of sealed radioactive sources

    International Nuclear Information System (INIS)

    New environmental regulations and radiation safety standards are being implemented almost daily to ensure radiation safety, in particular for practices causing exposures to undue radiation doses. A particular emphasis of real challenge for organizations and users of radiation sources has to be for proper radiological safety assessment and is becoming cost effectively to be prepared for auditing. Special concern for the environment is of global . nature, and hence environmental auditing has been and will continue to be an essential practice for improving the environment and for meeting the relevant regulations and standards. In general, most facilities that deal with radioactive sources undertake strict safety measures in terms of personnel radiation protection, handling procedures and security. Hence, those measures should comply with the requirements of the environmental protection standards. Accordingly, a successful quality management system must balance realities of organization and personnel in achieving quality objectives. Organizational principles are found in the technical aspects of' quality management, such as, charting, requirements, measurements, procedures, ... , etc. Human principles are found in the communication side of quality management (e.g. meetings, ,decision making, ,teams, ... , etc). The quality management must understand and balance skills needed to blend them together. Large gamma irradiators present a high potential radiation hazard to the surrounding environment, since the amount of radioactivity is of the order of (P Bq) and a very high dose rates are produced during irradiation. Application of environmental radiation control deemed by regulatory authority and a proper quality management system by the utility would serve public health and safety

  19. Radiation-induced changes to mammalian cells as a precipitating factor in somatic radiation injuries

    International Nuclear Information System (INIS)

    Radiation-induced inhibitions of proliferation were assessed in cell cultures examined for their colony-forming abilities as well as from changes of growth curves. The results of those measurements, along with simulating calculations, underlined the fact that the colony-forming capacity of a cell can by no means be equated with cell survival, unless due attention is given to the size of the colony formed. It is the size of the colony that provides a measure of the damage done to the irradiated cell. Cells counts are the most reliable method to ascertain the course of proliferation following radiation exposure. The difference between the two methods mentioned became particularly evident in studies with radiation protection substances. Dithiothreitol (DTT) and mercaptopropionyl glycine (MPG) were on the basis of colony formation clearly shown to offer protection against radiation. The growth curves, however, revealed that the proliferation of cells irradiated in the presence of radiation protection substances was even more strongly inhibited than that of cells influenced by irradiation alone. The neutral elution method failed to provide irrefutable evidence that the rate of double strand breaks was reduced by those two substances. Cysteamine and DTT were, however, able to inhibit radiation-induced changes to the proteins of human erythrocyte membranes. (orig./MG)

  20. Stem cells in radiation and oral cancer research

    International Nuclear Information System (INIS)

    Cancer stem cells (CSCs) are defined as a small sub population of cancer cells that constitute a pool of self sustaining cells with the exclusive ability to cause the heterogeneous lineages of cancer cells that comprise the tumour. There are three main characteristics of CSCs. Initially the cell must show potent tumour initiation in that it can regenerate the tumour which it was derived from a limited number of cells. In addition, the cells should demonstrate self renewal in vivo, which is practically observed via regrowth of phenotypically indistinguishable and heterogeneous tumours following serial transplantation of re-isolated CSCs in secondary and tertiary recipients. Finally, the cells must show a differentiation capacity, allowing them to give rise to a heterogeneous progeny, which represents a phenocopy of the original tumour. This article highlights the radiation therapy resulting in radiation resistance in cancer stem cells. (author)

  1. Radiation safety and quality control assurance in X-ray diagnostics 1998

    International Nuclear Information System (INIS)

    The report is based on a seminar course of lectures 'Radiation safety and quality assurance in X-ray diagnostics 1998' organized by the Radiation and Nuclear Safety Authority (STUK) in Finland. The lectures included actual information on X-ray examinations: methods of quality assurance, methods of measuring and calculating patient doses, examination frequencies, patient doses, occupational doses, and radiation risks. Paediatric X-ray examinations and interventional procedures were the most specific topics. The new Council Directive 97/43/Euratom on medical exposure, and the European Guidelines on quality criteria for diagnostic radiographic images, were discussed in several lectures. Lectures on general radiation threats and preparedness, examples of radiation accidents, and emergency preparedness in hospitals were also included. (editor)

  2. Towards a better characterisation of radiation quality using track structure models

    International Nuclear Information System (INIS)

    Many current track structure calculations are based on Monte-Carlo simulations which have to be performed for each individual case. Analytical models, on the other hand supply general formulations which can easily adapted to different conditions. Since they are continuous they oversimplify the real situation and are not suitable to be applied to very specific molecular structures. Nevertheless they are very useful and may even be more realistic than Monte-Carlo models as the molecules in the cell are more complicated than a composition of simple geometrical forms. Analytical models can be used to derive distributions of specific energies in various site sizes, range restricted LET and proximity functions. Experimental data support the main findings of these approaches. The quantities derived may serve as better descriptors of radiation quality than LET which is obviously inadequate but still widely used. The paper will illustrate these points by giving experimental examples both from the physical and the biological field. (authors)

  3. Virtual monochromatic imaging in dual-source dual-energy CT: Radiation dose and image quality

    OpenAIRE

    Yu, Lifeng; Christner, Jodie A.; Leng, Shuai; Wang, Jia; Fletcher, Joel G.; McCollough, Cynthia H.

    2011-01-01

    Purpose: To evaluate the image quality of virtual monochromatic images synthesized from dual-source dual-energy computed tomography (CT) in comparison with conventional polychromatic single-energy CT for the same radiation dose.

  4. Radiation therapy oncology group: 3-D CRT quality assurance guidelines

    International Nuclear Information System (INIS)

    Purpose: Guidelines to conduct multi-institutional three-dimensional conformal radiation therapy (3-D CRT) clinical trials are needed as the modality emerges from a single institution procedure to a research tool in multi-institution clinical group trials. The guidelines are used (1) to ensure that participating institutions have the proper equipment and appropriate techniques to administer 3D CRT; (2) to define a standard data set to be submitted to a review center for each treated patient to assess protocol compliance; and (3) to establish a quality assurance (QA) review process of the submitted data. Materials and Methods: Computer hardware and software components have been implemented which allow the digital data transfer (via either the Internet or magnetic tape), display, manipulation, and storage of a 3D CRT protocol patient treatment planning and image data set for QA review. Each participating institution is required to complete a 3D CRT Facility Questionnaire and submit it to the RTOG 3-D QA Center prior to enrolling patients on a 3-D CRT protocol. In addition, a protocol 'dry run' test has been designed to demonstrate each participating institutions' ability to submit a protocol compliant data set prior to placing patients on a 3D CRT study. This dry run test involves the digital transfer of all protocol required data and the supporting hard copy documentation excepting simulation or portal films/images. Results: The 3D CRT Facility Questionnaire includes descriptions of: (1) linac model, collimation system and energies to be used; (2) isocenter accuracy for gantry, collimator, and couch rotations; (3) type of immobilization repositioning system and patient motion studies if required by protocol (set-up uncertainty, organ movement); and (4) treatment verification system(s). The 3-D RTP system must have the following capabilities: (1) ability to handle at least 40 axial CT slices; (2) beam's-eye-view (BEV) display; (3) calculate 3-D dose matrices; (4

  5. Open Cell Conducting Foams for High Synchrotron Radiation Beam Liners

    OpenAIRE

    Petracca, Stefania; Stabile, Arturo

    2014-01-01

    The possible use of open-cell conductive foams in high synchrotron radiation particle accelerator beam liners is considered. Available materials and modeling tools are reviewed, potential pros and cons are discussed, and preliminary conclusions are drawn.

  6. Engineering hot-cell windows for radiation protection

    International Nuclear Information System (INIS)

    Radiation protection considerations in the design and construction of hot-cell windows are discussed. The importance of evaluating the potential gamma spectra and neutron source terms is stressed. 11 references

  7. Mammalian cells exposed to ionizing radiation: Structural and biochemical aspects.

    Science.gov (United States)

    Sabanero, Myrna; Azorín-Vega, Juan Carlos; Flores-Villavicencio, Lérida Liss; Castruita-Dominguez, J Pedro; Vallejo, Miguel Angel; Barbosa-Sabanero, Gloria; Cordova-Fraga, Teodoro; Sosa-Aquino, Modesto

    2016-02-01

    Acute or chronic exposure to ionizing radiation is a factor that may be hazardous to health. It has been reported that exposure to low doses of radiation (less than 50 mSv/year) and subsequently exposure to high doses produces greater effects in people. It has been reported that people who have been exposed to low doses of radiation (less than 50 mSv/year) and subsequently are exposed to high doses, have greater effects. However, at a molecular and biochemical level, it is an unknown alteration. This study, analyzes the susceptibility of a biological system (HeLa ATCC CCL-2 human cervix cancer cell line) to ionizing radiation (6 and 60 mSv/90 s). Our research considers multiple variables such as: total protein profile, mitochondrial metabolic activity (XTT assay), cell viability (Trypan blue exclusion assay), cytoskeleton (actin microfilaments), nuclei (DAPI), and genomic DNA. The results indicate, that cells exposed to ionizing radiation show structural alterations in nuclear phenotype and aneuploidy, further disruption in the tight junctions and consequently on the distribution of actin microfilaments. Similar alterations were observed in cells treated with a genotoxic agent (200 μM H2O2/1h). In conclusion, this multi-criteria assessment enables precise comparisons of the effects of radiation between various line cells. However, it is necessary to determine stress markers for integration of the effects of ionizing radiation. PMID:26656429

  8. Apoptosis of smooth muscle cells induced by radiation

    International Nuclear Information System (INIS)

    Objective: To study the effects and mechanism of 188Re on apoptosis of cultured smooth muscle cells (SMCs), and to explore the value of radiation induced SMCs apoptosis for preventing restenosis. Methods: The SMCs cultured in vitro were irradiated by 188Re with different doses. The trypan blue exclusion test, flow cytometry, JAM test, transmission electron microscopy and immunocytochemistry assay were used to investigate the effects of β-particles on apoptosis of SMCs, such as cell viability, cell apoptosis rate, DNA fragmentation, cell ultrastructural changes and related gene expression. Results: There were no significant changes of SMCs viability, cell apoptosis rate, DNA fragmentation and cellular ultrastructure in low-dose irradiation group, compared with control group. High-dose radiation (>2.96 GBq/L) on SMCs showed that viable cell proportion was markedly decreased, while cell apoptosis rate and DNA fragmentation were significantly increased, and cellular ultrastructure was destroyed. The expression of p53, bax gene was up regulated and bcl-2/bax was decreased while SMCs apoptosis occurred. Conclusions: Low-dose radiation on SMCs, which could inhibit completely SMCs proliferation, did not show any effects on cell viability, cell apoptosis rate, cell ultrastructure and DNA fragmentation. High-dose radiation could result in significant SMCs apoptosis. Up-regulated p53, bcl-2 and bax gene took a part in cell apoptosis induced by radiation. Low-dose and low-dose rate radiation appeared to be an ideal intravascular radiotherapy for preventing restenosis, which could not only inhibit SMCs proliferation, but also preserve cell viability and integrity

  9. Air quality and radiative forcing impacts of anthropogenic volatile organic compound emissions from ten world regions

    OpenAIRE

    M. M. Fry; M. D. Schwarzkopf; Adelman, Z.; West, J. J.

    2013-01-01

    Non-methane volatile organic compounds (NMVOCs) influence air quality and global climate change through their effects on secondary air pollutants and climate forcers. Here we simulate the air quality and radiative forcing (RF) impacts of changes in ozone, methane, and sulfate from halving anthropogenic NMVOC emissions globally and from 10 regions individually, using a global chemical transport model and a standalone radiative transfer model. Halving global NMVOC emissions decreases glo...

  10. Air quality and radiative forcing impacts of anthropogenic volatile organic compound emissions from ten world regions

    OpenAIRE

    M. M. Fry; M. D. Schwarzkopf; Adelman, Z.; West, J. J.

    2014-01-01

    Non-methane volatile organic compounds (NMVOCs) influence air quality and global climate change through their effects on secondary air pollutants and climate forcers. Here we simulate the air quality and radiative forcing (RF) impacts of changes in ozone, methane, and sulfate from halving anthropogenic NMVOC emissions globally and from 10 regions individually, using a global chemical transport model and a standalone radiative transfer model. Halving global NMVOC emissions de...

  11. Influence of radiation processing of grapes on wine quality

    Science.gov (United States)

    Gupta, Sumit; Padole, Rupali; Variyar, Prasad S.; Sharma, Arun

    2015-06-01

    Grapes (Var. Shiraz and Cabernet) were subjected to radiation processing (up to 2 kGy) and wines were prepared and matured (4 months, 15 °C). The wines were analyzed for chromatic characteristics, total anthocyanin (TA), phenolic (TP) and total antioxidant (TAC) content. Aroma of wines was analyzed by GC/MS and sensory analysis was carried out using descriptive analysis. TA, TP and TAC were 77, 31 and 37 percent higher for irradiated (1500 Gy) Cabernet wines, while irradiated Shiraz wines demonstrated 47, 18 and 19 percent higher TA, TP and TAC, respectively. HPLC-DAD analysis revealed that radiation processing of grapes resulted in increased extraction of phenolic constituents in wine with no qualitative changes. No major radiation induced changes were observed in aroma constituents of wine. Sensory analysis revealed that 1500 Gy irradiated samples had higher fruity and berry notes. Thus, radiation processing of grapes resulted in wines with improved organoleptic and antioxidant properties.

  12. Ionizing radiation and cell cycle progression in ataxia telangiectasia

    International Nuclear Information System (INIS)

    Exposure of mammalian cells to ionizing radiation causes delay in normal progress through the cell cycle at a number of different checkpoints. Abnormalities in these checkpoints have been described for ataxia telangiectasia cells after irradiation. In this report we show that these abnormalities occur at different phases in the cell cycle in several ataxia telangiectasia lymphoblastoid cells. Ataxia telangiectasia cells, synchronized in late G1 phase with either mimosine or aphidicolin and exposed to radiation, showed a reduced delay in entering S phase compared to irradiated control cells. Failure to exhibit G1-phase delay in ataxia telangiectasia cells is accompanied by a reduced ability of radiation to activate the product of the tumor suppressor gene p53, a protein involved in G1/S-phase delay. When the progress of irradiated G1-phase cells was followed into the subsequent G2 and G1 phases ataxia telangiectasia cells showed a more pronounced accumulation in G2 phase than control cells. When cells were irradiated in S phase and extent of delay was more evident in G2 phase and ataxia telangiectasia cells were delayed to a greater extent. These results suggest that the lack of initial delay in both G1 and S phases to the radiosensitivity observed in this syndrome. 26 refs., 3 figs., 2 tabs

  13. Immobilization of yeast cells by radiation-induced polymerization

    International Nuclear Information System (INIS)

    Radiation-induced polymerization method was applied to the immobilization of yeast cells. The effects of irradiation, cooling and monomer, which are neccessary for polymerization, were recovered completely by subsequent aerobical incubation of yeast cells. The ethanol productive in immobilized yeast cells increased with the increase of aerobical incubation period. The growth of yeast cells in immobilized yeast cells was indicated. The maximum ethanol productivity in immobilized yeast cell system was around three times as much as that in free yeast cell system. (orig.)

  14. Cybernetical investigations on the radiation effects on tumour cells

    International Nuclear Information System (INIS)

    The goal of this work was to find suitable conditions for the in-vitro investigations with these E.A.T. cells so that basic experiments carried out with yeast cells will also be possible. Systematic investigations on cell multiplication led to reliable and definite test conditions for these cells. For the evaluation of the data which had been measured with several sorts of radiation the cybernetic model was applied. (orig./MG)

  15. Radiation response of floating gate EEPROM memory cells

    International Nuclear Information System (INIS)

    The effect of radiation on a floating gate EEPROM nonvolatile memory cell is determined experimentally and modeled analytically. The new model predicts the threshold voltage change resulting from radiation. A screen based on the initial 1 state (excess electron) threshold voltage is shown to be necessary to assure data retention during irradiation. Techniques to increase radiation hardness are also described. The hardness of floating gate cells is shown to be limited to less than 100 krad(Si) for a fixed reference sense amplifier. The use of a differential sense amplifier may increase this limit. Therefore, floating gate memories should be useful for those applications requiring low total-doses

  16. Radiation effects on membranes - 1. Cellular permeability and cell survival

    International Nuclear Information System (INIS)

    The effect of various doses of γ radiation (5-60 krad) on the membrane permeability and cell survival of Candida albicans, a pathogenic yeast, was investigated. A reduction in the cell survival and in the accumulation of amino acids (proline, glycine, lysine, and glutamic acid) was observed following irradiation. The rate of oxygen uptake, which is often associated with transport, was also reduced. There was no damage to available sulfhydryl groups following the exposure of cells to various doses of γ radiation. The membrane lipid composition of C. albicans cells can be altered by growing them in alkanes of varying chain lengths. The effects of such altered lipid composition on radiosensitivity was examined. It was observed that C. albicans cells with altered lipid content acquire resistance to γ radiation

  17. The concept of radiation-enhanced stem cell differentiation

    Directory of Open Access Journals (Sweden)

    Mieloch Adam A.

    2015-09-01

    Full Text Available Background. Efficient stem cell differentiation is considered to be the holy grail of regenerative medicine. Pursuing the most productive method of directed differentiation has been the subject of numerous studies, resulting in the development of many effective protocols. However, the necessity for further improvement in differentiation efficiency remains. This review contains a description of molecular processes underlying the response of stem cells to ionizing radiation, indicating its potential application in differentiation procedures. In the first part, the radiation-induced damage response in various types of stem cells is described. Second, the role of the p53 protein in embryonic and adult stem cells is highlighted. Last, the hypothesis on the mitochondrial involvement in stem cell development including its response to ionizing radiation is presented.

  18. Effects of ionizing radiation on differentiation of murine bone marrow cells into mast cells

    International Nuclear Information System (INIS)

    Mast cells, immune effector cells produced from bone marrow cells, play a major role in immunoglobulin E–mediated allergic responses. Ionizing radiation affects the functions of mast cells, which are involved in radiation-induced tissue damage. However, whether ionizing radiation affects the differential induction of mast cells is unknown. Here we investigated whether bone marrow cells of X-irradiated mice differentiated into mast cells. To induce mast cells, bone marrow cells from X-irradiated and unirradiated mice were cultured in the presence of cytokines required for mast cell induction. Although irradiation at 0.5 Gy and 2 Gy decreased the number of bone marrow cells 1 day post-irradiation, the cultured bone marrow cells of X-irradiated and unirradiated mice both expressed mast cell–related cell-surface antigens. However, the percentage of mast cells in the irradiated group was lower than in the unirradiated group. Similar decreases in the percentage of mast cells induced in the presence of X-irradiation were observed 10 days post irradiation, although the number of bone marrow cells in irradiated mice had recovered by this time. Analysis of mast cell function showed that degranulation of mast cells after immunoglobulin E–mediated allergen recognition was significantly higher in the X-irradiated group compared with in the unirradiated group. In conclusion, bone marrow cells of X-irradiated mice differentiated into mast cells, but ionizing radiation affected the differentiation efficiency and function of mast cells. (author)

  19. Radiation hardened high efficiency silicon space solar cell

    International Nuclear Information System (INIS)

    A silicon solar cell with AMO 19% Beginning of Life (BOL) efficiency is reported. The cell has demonstrated equal or better radiation resistance when compared to conventional silicon space solar cells. Conventional silicon space solar cell performance is generally ∼ 14% at BOL. The Radiation Hardened High Efficiency Silicon (RHHES) cell is thinned for high specific power (watts/kilogram). The RHHES space cell provides compatibility with automatic surface mounting technology. The cells can be easily combined to provide desired power levels and voltages. The RHHES space cell is more resistant to mechanical damage due to micrometeorites. Micro-meteorites which impinge upon conventional cells can crack the cell which, in turn, may cause string failure. The RHHES, operating in the same environment, can continue to function with a similar crack. The RHHES cell allows for very efficient thermal management which is essential for space cells generating higher specific power levels. The cell eliminates the need for electrical insulation layers which would otherwise increase the thermal resistance for conventional space panels. The RHHES cell can be applied to a space concentrator panel system without abandoning any of the attributes discussed. The power handling capability of the RHHES cell is approximately five times more than conventional space concentrator solar cells

  20. Radiation-Induced Notch Signaling in Breast Cancer Stem Cells

    Energy Technology Data Exchange (ETDEWEB)

    Lagadec, Chann [Department of Radiation Oncology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, California (United States); Vlashi, Erina [Department of Radiation Oncology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, California (United States); Jonsson Comprehensive Cancer Center at UCLA, Los Angeles, California (United States); Alhiyari, Yazeed; Phillips, Tiffany M.; Bochkur Dratver, Milana [Department of Radiation Oncology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, California (United States); Pajonk, Frank, E-mail: fpajonk@mednet.ucla.edu [Department of Radiation Oncology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, California (United States); Jonsson Comprehensive Cancer Center at UCLA, Los Angeles, California (United States)

    2013-11-01

    Purpose: To explore patterns of Notch receptor and ligand expression in response to radiation that could be crucial in defining optimal dosing schemes for γ-secretase inhibitors if combined with radiation. Methods and Materials: Using MCF-7 and T47D breast cancer cell lines, we used real-time reverse transcription–polymerase chain reaction to study the Notch pathway in response to radiation. Results: We show that Notch receptor and ligand expression during the first 48 hours after irradiation followed a complex radiation dose–dependent pattern and was most pronounced in mammospheres, enriched for breast cancer stem cells. Additionally, radiation activated the Notch pathway. Treatment with a γ-secretase inhibitor prevented radiation-induced Notch family gene expression and led to a significant reduction in the size of the breast cancer stem cell pool. Conclusions: Our results indicate that, if combined with radiation, γ-secretase inhibitors may prevent up-regulation of Notch receptor and ligand family members and thus reduce the number of surviving breast cancer stem cells.

  1. Radiation-Induced Notch Signaling in Breast Cancer Stem Cells

    International Nuclear Information System (INIS)

    Purpose: To explore patterns of Notch receptor and ligand expression in response to radiation that could be crucial in defining optimal dosing schemes for γ-secretase inhibitors if combined with radiation. Methods and Materials: Using MCF-7 and T47D breast cancer cell lines, we used real-time reverse transcription–polymerase chain reaction to study the Notch pathway in response to radiation. Results: We show that Notch receptor and ligand expression during the first 48 hours after irradiation followed a complex radiation dose–dependent pattern and was most pronounced in mammospheres, enriched for breast cancer stem cells. Additionally, radiation activated the Notch pathway. Treatment with a γ-secretase inhibitor prevented radiation-induced Notch family gene expression and led to a significant reduction in the size of the breast cancer stem cell pool. Conclusions: Our results indicate that, if combined with radiation, γ-secretase inhibitors may prevent up-regulation of Notch receptor and ligand family members and thus reduce the number of surviving breast cancer stem cells

  2. Model of cell response to {\\alpha}-particle radiation

    CERN Document Server

    Liu, Longjian

    2012-01-01

    Starting from a general equation for organism (or cell system) growth and attributing additional cell death rate (besides the natural rate) to therapy, we derive an equation for cell response to {\\alpha} radiation. Different from previous models that are based on statistical theory, the present model connects the consequence of radiation with the growth process of a biosystem and each variable or parameter has meaning regarding the cell evolving process. We apply this equation to model the dose response for {\\alpha}-particle radiation. It interprets the results of both high and low linear energy transfer (LET) radiations. When LET is high, the additional death rate is a constant, which implies that the localized cells are damaged immediately and the additional death rate is proportional to the number of cells present. While at low LET, the additional death rate includes a constant term and a linear term of radiation dose, implying that the damage to some cell nuclei has a time accumulating effect. This model ...

  3. Classical Radiation Reaction in Particle-In-Cell Simulations

    CERN Document Server

    Vranic, Marija; Fonseca, Ricardo A; Silva, Luis O

    2015-01-01

    Under the presence of ultra high intensity lasers or other intense electromagnetic fields the motion of particles in the ultrarelativistic regime can be severely affected by radiation reaction. The standard particle-in-cell (PIC) algorithms do not include radiation reaction effects. Even though this is a well known mechanism, there is not yet a definite algorithm nor a standard technique to include radiation reaction in PIC codes. We have compared several models for the calculation of the radiation reaction force, with the goal of implementing an algorithm for classical radiation reaction in the Osiris framework, a state-of-the-art PIC code. The results of the different models are compared with standard analytical results, and the relevance/advantages of each model are discussed. Numerical issues relevant to PIC codes such as resolution requirements, application of radiation reaction to macro particles and computational cost are also addressed. The Landau and Lifshitz reduced model is chosen for implementatio...

  4. Radiation related basic cancer research : research for radiation induced tumor cell killing

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Hoon; Hong, Seok Il; Cho, Kyung Ja; Kim, Byung Gi; Lee, Kee Ho; Nam, Myung Jin

    1999-04-01

    The radioresistant clones was established from human U251 glioblastoma cell line through intermittently exposed to 3 Gy gamma-radiation for six months. Treatment of SNU-16 cells with various doses of radiation, TNF alpha and PMA resulted in a decrease in cell viability. The results prove that cell death of SNU16 is a apoptosis mediated by caspase-3. We have examined the expression of bcl-2 and c-myc in cervical cancer specimens and cervical intraepithelial neoplasia (CIN) to determine the role of coexpression of bcl-3 and c-myc during progression into cervical cancer. The frequent alterations in FHIT expression in many cervical carcinomas and their cell lines suggest that FHIT gene alterations are pla a role in cervical tumorigenesis. According to these correlation between the viability and apoptosis of RD cells, the proper range of the dosage for the investigation of differentiation potency in RD cells was assessed as 1 to 3Gy.

  5. Radiation related basic cancer research : research for radiation induced tumor cell killing

    International Nuclear Information System (INIS)

    The radioresistant clones was established from human U251 glioblastoma cell line through intermittently exposed to 3 Gy gamma-radiation for six months. Treatment of SNU-16 cells with various doses of radiation, TNF alpha and PMA resulted in a decrease in cell viability. The results prove that cell death of SNU16 is a apoptosis mediated by caspase-3. We have examined the expression of bcl-2 and c-myc in cervical cancer specimens and cervical intraepithelial neoplasia (CIN) to determine the role of coexpression of bcl-3 and c-myc during progression into cervical cancer. The frequent alterations in FHIT expression in many cervical carcinomas and their cell lines suggest that FHIT gene alterations are pla a role in cervical tumorigenesis. According to these correlation between the viability and apoptosis of RD cells, the proper range of the dosage for the investigation of differentiation potency in RD cells was assessed as 1 to 3Gy

  6. Radiation sensitization studies by silymarin on HCT-15 cells

    International Nuclear Information System (INIS)

    Radiotherapy has been widely used for treatment of human cancers. However, cancer cells develop radioresistant phenotypes following multiple exposures to the treatment agent that decrease the efficacy of radiotherapy. Here it was investigated that the radiation sensitization effects of silymarin found in colon cancer. The aim of this study was to investigate mechanisms involved in radiation sensitization growth inhibitory effect of silymarin in combination with radiation, in Human colon carcinoma (HCT-15). The human colon carcinoma was utilized and SRB-assay was performed to study anti-proliferative effect of silymarin in combination with gamma radiation (2 Gy) appropriate radiation dose was optimized and confirmed by clonogenic assay. Microscopic analysis was done by staining with Hoechst-33342, DAPI, Propidium iodide to confirm the presence of apoptosis. Nitric oxide production, changes in lipid peroxidation, Cell cycle analysis were carried out and mitochondrial membrane potential was measured by uptake of cationic dye JC-1 by using flow cytometer. Silymarin in combination with radiation (2 Gy) inhibited 70% ± 5% population growth of HCT-15 cells in time and dose dependent manner. Pre treatment of cells with silymarin for 30 min before radiation was found to be most effective for radiation sensitization. There was 25% increase in levels of nitric oxide as compare to control, whereas 2.5 fold change in lipid peroxidation with respect to control. IR-induced apoptosis in HCT-15 cell line was significantly enhanced by silymarin, as reflected by viability, DNA fragmentation, and mitochondrial dysfunction. Additionally, silymarin in combination with IR is found to be effective in sensitization of HCT-15 cells. In vivo studies on development of tumor and sensitization aspects needs to done in future. (author)

  7. Sensitization of radiation-induced cell death by genistein

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Rim; Kim, In Gyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-03-15

    A number of epidemiological studies as well as biological experiments, showed that genistein, one of the isoflavone, prevents prostate cancer occurrence. In this study, we showed that genistein inhibited the cell proliferation of human promyeoltic leukemia HL-60 cells and induced G2/M phase arrest. In addition, combination of genistein treatment and {gamma}-irradiation displayed synergistic effect in apoptotic cell death of HL-60 cells. This means that the repair of genistein-induced DNA damage was hindered by {gamma}-irradiation and thus cell death was increased. In conclusion, genistein is one of the important chemicals that sensitize radiation-induced cell death.

  8. Radiation Interaction with Therapeutic Drugs and Cell Membranes

    International Nuclear Information System (INIS)

    This transient permeabilized state of the cell membrane, named the 'cell electroporation' (CE) can be used to increase cells uptake of drugs that do not readily pass cell membrane, thus enabling their cytotoxicity. The anticancer drugs, such as bleomycin (BL) and cisplatin, are the most candidates for the combined use with ionizing and non-ionizing radiation fields. The methods and installations for the cell electroporation by electron beam (EB) and microwave (MW) irradiation are presented. The viability tests of the human leukocytes under EB and MW exposure with/without the BL in the cell cultures are discussed

  9. Effect of gamma radiation on microbial safety and nutritional quality of kachri (Cucumis callosus)

    International Nuclear Information System (INIS)

    Fresh dried and old (6-12 months) dried kachri (Cucumis callosus) were treated with 0, 2.5, 5 and 7 kGy of gamma radiation in a Cobalt 60 gamma cell (GC-1200). The irradiated samples of kachri were stored at room temperature (28±2 °C). Total bacterial count and nutrient composition were evaluated immediately after irradiation and at regular intervals of 1 month during 3 months of storage. Results indicated that gamma radiation reduced the total bacterial counts of dried samples of both fresh and old dried kachri. Dose of 5.0 kGy was sufficient to eliminate total bacterial count and there was no microbial growth in 5.0 kGy irradiated samples during the storage period. No significant differences were observed in the proximate composition of both types of kachri at all irradiation doses. It was concluded that irradiation treatments of kachri improves keeping quality of both freshly dried and old dried Kachri. (author)

  10. Temporary corneal stem cell dysfunction after radiation therapy

    International Nuclear Information System (INIS)

    Radiation therapy can cause corneal and conjuctival abnormalities that sometimes require surgical treatment. Corneal stem cell dysfunction is described, which recovered after the cessation of radiation. Methods - A 44-year-old man developed a corneal epithelial abnormality associated with conjuctival and corneal inflammation following radiation therapy for maxillary cancer. Examination of brush cytology samples showed goblet cells in the upper and lower parts of the cornea, which showed increased fluorescein permeability, and intraepithelial lymphocytes. Impression cytology showed goblet cells in the same part of the cornea. Specular microscopy revealed spindle type epithelial cells. Patient follow up included artificial tears and an antibiotic ophthalmic ointment. The corneal abnormalities resolved after 4 months with improved visual acuity without any surgical intervention, but the disappearance of the palisades of Vogt did not recover at 1 year after radiation. Radiation therapy in this patient caused temporary stem cell dysfunction which resulted in conjunctivalisation in a part of the cornea. Although limbal stem cell function did not fully recover, this rare case suggested that medical options should be considered before surgery. (Author)

  11. Applications of single cell gel electrophoresis assay in radiation research

    International Nuclear Information System (INIS)

    The single cell gel electrophoresis (SCGE), also called comet assay, is a sensitive and rapid method for DNA damage detection in individual mammalian cell. Its use has increased significantly in the past few years. Applications in the field of radiation medicine are reviewed and possible future directions of the technique are briefly explored

  12. Cone Penetrometer Load Cell Temperature and Radiation Testing Results

    Energy Technology Data Exchange (ETDEWEB)

    Follett, Jordan R.

    2013-08-28

    This report summarizes testing activities performed at the Pacific Northwest National Laboratory to verify the cone penetrometer load cell can withstand the tank conditions present in 241-AN-101 and 241-AN-106. The tests demonstrated the load cell device will operate under the elevated temperature and radiation levels expected to be encountered during tank farm deployment of the device.

  13. The radiation response of cells recovering after chronic hypoxia

    International Nuclear Information System (INIS)

    Experiments were performed to study the influence of hypoxic pretreatment on the radiation response of A431 human squamous carcinoma cells. Reaeration for 10 min after chronic hypoxia (greater than 2 h) was found to enhance the radiosensitivity of A431 cells, and the maximal effect was seen for those cells reaerated after 12 h of hypoxia. The radiosensitivity enhancement for reaerated cells after 12 h of hypoxia was maximized by 5 min after the return to aerobic conditions and reached the control level by 12 h of reaeration. This enhanced radiosensitive state was characterized by a reduced shoulder region and increased slope of the radiation dose-response curve for cells in both the exponential and plateau phases of growth. There was a slight increase in the number of G1 and decrease in the number of S and G2 + M cells for both exponential- and plateau-phase cultures following 12 h hypoxic treatment. Although growth inhibition induced by 12 h of hypoxia was seen for cells in the exponential phase, there was no cell number change in the plateau-phase culture after hypoxia. Plating efficiency (PE) of cells in both growth phases was reduced by 30% after hypoxia. Furthermore, in the exponential-phase culture, the extent of reduction in PE after hypoxia was similar among cells in different phases of the cell cycle. Although S-phase cells in exponentially growing cultures were relatively more resistant to radiation than G1 and G2 + M cells, the cell age-response pattern was the same whether the cells had been aerobic or hypoxic before reaeration and irradiation. Furthermore, the enhancement ratio associated with reaeration after 12 h of hypoxia for these three subpopulations of cells was 1.3. Our results indicate that the increase in radiosensitivity due to reaeration after chronic hypoxia is unlikely to be related to the changes of cell cycle stage and growth phase during hypoxic treatment

  14. Roles of ionizing radiation in cell transformation

    International Nuclear Information System (INIS)

    Earlier the authors described a repair misrepair model (RMR-I) which is applicable for radiations of low LET, e.g., x rays and gamma rays. RMR-II was described later. Here is introduced a mathematical modification of the RMR model, RMR-III, which is intended to describe lethal effects caused by heavily ionizing tracks. 31 references, 4 figures

  15. Tumour microenvironment and radiation response in sarcomas originating from tumourigenic human mesenchymal stem cells

    DEFF Research Database (Denmark)

    D'Andrea, Filippo Peder; Safwat, Akmal Ahmed; Burns, Jorge S.;

    2012-01-01

    to determine whether this heterogeneity persisted in tumours established from these clones, and whether the response to radiation treatment was principally governed by cell intrinsic qualities or by factors pertaining to the tumour microenvironment, such as the degree of hypoxia and vascularisation....... Methods: Immune deficient female mice were implanted on the backs with cells from one of the clones. The subsequent tumours were subjected to either radiation treatment or had the tumour microenvironment assayed, when they reached 400mm3. Radiation was given as a single fraction of 0 to 15 Gy and the...... degree of tumour control and time to three times the treatment volume were noted. Tumours used for the microenvironmental assay had intratumoral hypoxia measured by the Eppendorf oxygen electrode and Pimonidazole staining, and the extent of vascularisation determined by a microvasculature density assay...

  16. Ethacrynic acid: a novel radiation enhancer in human carcinoma cells

    International Nuclear Information System (INIS)

    Purpose: Because agents that interfere with thiol metabolism and glutathione S-transferase (GST) functions have been shown to enhance antitumor effects of alkylating agents in vitro and in vivo, the present study was conceived on the basis that an inhibitor of GST would enhance the radiation response of some selected human carcinoma cells. Ethacrynic acid (EA) was chosen for the study because it is an effective inhibitor of GST and is a well known diuretic in humans. Methods and Materials: Experiments were carried out with well-established human tumor cells in culture growing in Eagle's minimum essential medium (MEM) supplemented with 10% fetal calf serum (FCS). Cell lines used were MCF-7, MCF-7 adriamycin resistant (AR) cells (breast carcinoma), HT-29 cells (colon carcinoma), DU-145 cells (prostate carcinoma), and U-373 cells (malignant glioma). Cell survival following the exposure of cells to drug alone, radiation alone, and a combined treatment was assayed by determining the colony-forming ability of single plated cells in culture to obtain dose-survival curves. The drug enhancement ratio was correlated with levels of GST. Results: The cytotoxicity of EA was most pronounced in MCF-7, U-373, and DU-145 cells compared to MCF-7 AR and HT-29 cells. The levels of GST activity were found to be lower in those EA-sensitive cells. A significant radiation enhancement was obtained with EA-sensitive cells exposed to nontoxic concentrations of the drug immediately before or after irradiation. The sensitizer enhancement ratio (SER) of MCF-7 cells was 1.55 with EA (20 μg/ml), while the SER of MCF-7 AR was less than 1.1. Based on five different human tumor cells, a clear inverse relationship was demonstrated between the magnitude of SER and GST levels of tumor cells prior to the combined treatment. Conclusion: The present results suggest that EA, which acts as both a reversible and irreversible inhibitor of GST activity, could significantly enhance the radiation response of

  17. Radiation safety and quality in diagnostic x-ray imaging 2001; Saeteilyturvallisuus ja laatu roentgendiagnostiikassa 2001

    Energy Technology Data Exchange (ETDEWEB)

    Servomaa, A.; Parviainen, T. (eds.)

    2001-05-01

    The obligations of the medical exposure directive (97/43/Euratom) for hospitals dominate the current activities in radiation protection in medical radiology. The directive gives special emphasis to radiation exposure of children, to examinations with high radiation doses and to radiation exposure in health screening programmes. The most important examinations with high doses are radiological interventions, where even acute skin effects are possible, and the computed tomography where the number of CT examinations makes only about 5% from the total number of x-ray examinations but the collective effective dose about 40% from the combined collective effective dose of all x-ray examinations. In the research projects financed by the European Commission, radiation exposures to paediatric patients have been measured in radiography, fluoroscopy and CT, and various dose assessment methods have been compared to develop a method for national follow-up of patients' radiation dose. The newest research project is focused on dosimetry and quality assurance in interventional radiology and digital imaging. Other actual topics are the development of radiation protection regulations and quality systems, education and training programmes, and clinical audits. This report deals with new radiation protection guides and recommendations and the education and training of radiological staff in radiation protection. One important topic is the development of national follow-up method of radiation exposure to patients and comparison of various dose assessment methods. Quality assurance in health care and in paediatric radiology, and the acceptance test and quality assurance measurements of radiological equipment are also described. (orig.)

  18. Mammalian cells exposed to ionizing radiation: structural and biochemical aspects

    International Nuclear Information System (INIS)

    Acute or chronic exposure to ionizing radiation is a factor that may be hazardous to health. It has been reported that exposure to low doses of radiation (less than 50 mSv / year) and subsequently exposure to high doses have greater effects in people. However, it is unknown molecular and biochemical level alteration. This study, analyzes the susceptibility of a biological system (HeLa Atcc CCL-2 human cervix cancer cell line) to ionizing radiation (6 and 60 mSv/ 90). Our evaluate multiple variables such as: total protein profile, mitochondrial metabolic activity (XTT assay), cell viability (Trypan blue exclusion assay), cytoskeleton (actin micro filaments), nuclei (D API), genomic DNA. The results indicate, that cells exposed to ionizing radiation structurally show alterations in nuclear phenotype and aneuploidy, further disruption in the tight junctions and consequently on the distribution of actin micro filaments. Similar alterations were observed in cells treated with a genotoxic agent (200μM H2O2/1 h). In conclusion, this multi-criteria assessment enables precise comparisons of the effects of radiation between any biological systems. However, it is necessary to determine stress markers for integration of the effects of ionizing radiation. (Author)

  19. Mammalian cells exposed to ionizing radiation: structural and biochemical aspects

    Energy Technology Data Exchange (ETDEWEB)

    Sabanero, M.; Flores V, L. L. [Universidad de Guanajuato, Departamento de Biologia, DCNE, Noria Alta s/n, 36250 Guanajuato, Gto. (Mexico); Azorin V, J. C.; Vallejo, M. A.; Cordova F, T.; Sosa A, M. [Universidad de Guanajuato, Departamento de Ingenieria Fisica, DCI, Loma del Bosque 103, Col. Lomas del Campestre, 37150 Leon, Guanajuato (Mexico); Castruita D, J. P. [Universidad de Guadalajara, Departamento de Ecologia, CUCBA, Las Agujas, 45100 Zapopan, Jalisco (Mexico); Barbosa S, G., E-mail: myrna.sabanero@gmail.com [Universidad de Guanajuato, Departamento de Ciencias Medicas, DCS, 20 de Enero No. 929, Col. Obregon, 37000 Leon, Guanajuato (Mexico)

    2015-10-15

    Acute or chronic exposure to ionizing radiation is a factor that may be hazardous to health. It has been reported that exposure to low doses of radiation (less than 50 mSv / year) and subsequently exposure to high doses have greater effects in people. However, it is unknown molecular and biochemical level alteration. This study, analyzes the susceptibility of a biological system (HeLa Atcc CCL-2 human cervix cancer cell line) to ionizing radiation (6 and 60 mSv/ 90). Our evaluate multiple variables such as: total protein profile, mitochondrial metabolic activity (XTT assay), cell viability (Trypan blue exclusion assay), cytoskeleton (actin micro filaments), nuclei (D API), genomic DNA. The results indicate, that cells exposed to ionizing radiation structurally show alterations in nuclear phenotype and aneuploidy, further disruption in the tight junctions and consequently on the distribution of actin micro filaments. Similar alterations were observed in cells treated with a genotoxic agent (200μM H{sub 2}O{sub 2}/1 h). In conclusion, this multi-criteria assessment enables precise comparisons of the effects of radiation between any biological systems. However, it is necessary to determine stress markers for integration of the effects of ionizing radiation. (Author)

  20. New Modeling Approaches to Investigate Cell Signaling in Radiation Response

    Science.gov (United States)

    Plante, Ianik; Cucinotta, Francis A.; Ponomarev, Artem L.

    2011-01-01

    Ionizing radiation damages individual cells and tissues leading to harmful biological effects. Among many radiation-induced lesions, DNA double-strand breaks (DSB) are considered the key precursors of most early and late effects [1] leading to direct mutation or aberrant signal transduction processes. In response to damage, a flow of information is communicated to cells not directly hit by the radiation through signal transduction pathways [2]. Non-targeted effects (NTE), which includes bystander effects and genomic instability in the progeny of irradiated cells and tissues, may be particularly important for space radiation risk assessment [1], because astronauts are exposed to a low fluence of heavy ions and only a small fraction of cells are traversed by an ion. NTE may also have important consequences clinical radiotherapy [3]. In the recent years, new simulation tools and modeling approaches have become available to study the tissue response to radiation. The simulation of signal transduction pathways require many elements such as detailed track structure calculations, a tissue or cell culture model, knowledge of biochemical pathways and Brownian Dynamics (BD) propagators of the signaling molecules in their micro-environment. Recently, the Monte-Carlo simulation code of radiation track structure RITRACKS was used for micro and nano-dosimetry calculations [4]. RITRACKS will be used to calculate the fraction of cells traversed by an ion and delta-rays and the energy deposited in cells in a tissue model. RITRACKS also simulates the formation of chemical species by the radiolysis of water [5], notably the .OH radical. This molecule is implicated in DNA damage and in the activation of the transforming growth factor beta (TGF), a signaling molecule involved in NTE. BD algorithms for a particle near a membrane comprising receptors were also developed and will be used to simulate trajectories of signaling molecules in the micro-environment and characterize autocrine

  1. Radiation Response of Cultured Human Cells Is Unaffected by Johrei

    Directory of Open Access Journals (Sweden)

    Zach Hall

    2007-01-01

    Full Text Available Johrei has been credited with healing thousands from radiation wounds after the Hiroshima and Nagasaki bombs in 1945. This alternative medical therapy is becoming increasingly popular in the United States, as are other Energy Medicine modalities that purport to influence a universal healing energy. Human brain cells were cultured and exposed to increasing doses of ionizing radiation. Experienced Johrei practitioners directed healing intentionality toward the cells for 30 min from a distance of 20 cm and the fate of the cells was observed by computerized time-lapse microscopy. Cell death and cell divisions were tallied every 30 min before, during and after Johrei treatment for a total of 22.5 h. An equal number of control experiments were conducted in which cells were irradiated but did not receive Johrei treatment. Samples were assigned to treatment conditions randomly and data analysis was conducted in a blinded fashion. Radiation exposure decreased the rate of cell division (cell cycle arrest in a dose-dependent manner. Division rates were estimated for each 30 min and averaged over 8 independent experiments (4 control and 4 with Johrei treatment for each of 4 doses of X-rays (0, 2, 4 and 8 Gy. Because few cell deaths were observed, pooled data from the entire observation period were used to estimate death rates. Analysis of variance did not reveal any significant differences on division rate or death rate between treatment groups. Only radiation dose was statistically significant. We found no indication that the radiation response of cultured cells is affected by Johrei treatment.

  2. Radiation response of cultured human cells is unaffected by Johrei.

    Science.gov (United States)

    Hall, Zach; Luu, Tri; Moore, Dan; Yount, Garret

    2007-06-01

    Johrei has been credited with healing thousands from radiation wounds after the Hiroshima and Nagasaki bombs in 1945. This alternative medical therapy is becoming increasingly popular in the United States, as are other Energy Medicine modalities that purport to influence a universal healing energy. Human brain cells were cultured and exposed to increasing doses of ionizing radiation. Experienced Johrei practitioners directed healing intentionality toward the cells for 30 min from a distance of 20 cm and the fate of the cells was observed by computerized time-lapse microscopy. Cell death and cell divisions were tallied every 30 min before, during and after Johrei treatment for a total of 22.5 h. An equal number of control experiments were conducted in which cells were irradiated but did not receive Johrei treatment. Samples were assigned to treatment conditions randomly and data analysis was conducted in a blinded fashion. Radiation exposure decreased the rate of cell division (cell cycle arrest) in a dose-dependent manner. Division rates were estimated for each 30 min and averaged over 8 independent experiments (4 control and 4 with Johrei treatment) for each of 4 doses of X-rays (0, 2, 4 and 8 Gy). Because few cell deaths were observed, pooled data from the entire observation period were used to estimate death rates. Analysis of variance did not reveal any significant differences on division rate or death rate between treatment groups. Only radiation dose was statistically significant. We found no indication that the radiation response of cultured cells is affected by Johrei treatment. PMID:17549235

  3. Radiation protection of patients and quality controls in teleradiology

    Energy Technology Data Exchange (ETDEWEB)

    Vermiglio, G.; Testagrossa, B.; Sansotta, C.; Tripepi, M.G. [Messina Univ., Dept. of Protezionistica Ambientale, Sanitaria, Sociale ed Industriale (Italy)

    2006-07-01

    Nowadays, it is well-known that tele-radiology represents the new frontier of radiodiagnostic imaging. In this case, the continuous broadening of transmission bands and the more sophisticated procedures of information packaging constitute a no negligible inducement. Moreover, standards used to convert analogical signals into the digital ones, necessary to transfer via ether radiological images and information, involve a more limited loss of information. Nevertheless, unlike the common images, in case of the X-ray diagnostic images it must take into account that the EURATOM Council Directives give the health physicist all the procedures to be followed for checking the status of X-ray equipments. In particular, the EURATOM Council Directives provide minimum criteria of acceptance for parameters that characterised the correct working of the radiological equipments and the guide lines for standardised execution of X-ray images, in order to obtain high quality information. In addiction, for maintaining such level it is necessary to adopt adequate programs of Quality Assurance. Naturally, the high quality of radiological images must be conserved after the transmission of information. So, in order to evaluate the amount of losses that can be introduced after transferring the X-ray images from source to user, the authors have carried out specific procedures in order to evaluate the quality level of the images after transmission and to compare them with the correspondent ones acquired at the equipment console. To this aim, the AAs have identified all the parameters able to verify the quality level of the images and measured the values obtained for the directly acquired images and the transferred ones. They have also considered different kinds of transmission protocols to define suitable procedures of remote quality controls. (authors)

  4. Radiation protection of patients and quality controls in teleradiology

    International Nuclear Information System (INIS)

    Nowadays, it is well-known that tele-radiology represents the new frontier of radiodiagnostic imaging. In this case, the continuous broadening of transmission bands and the more sophisticated procedures of information packaging constitute a no negligible inducement. Moreover, standards used to convert analogical signals into the digital ones, necessary to transfer via ether radiological images and information, involve a more limited loss of information. Nevertheless, unlike the common images, in case of the X-ray diagnostic images it must take into account that the EURATOM Council Directives give the health physicist all the procedures to be followed for checking the status of X-ray equipments. In particular, the EURATOM Council Directives provide minimum criteria of acceptance for parameters that characterised the correct working of the radiological equipments and the guide lines for standardised execution of X-ray images, in order to obtain high quality information. In addiction, for maintaining such level it is necessary to adopt adequate programs of Quality Assurance. Naturally, the high quality of radiological images must be conserved after the transmission of information. So, in order to evaluate the amount of losses that can be introduced after transferring the X-ray images from source to user, the authors have carried out specific procedures in order to evaluate the quality level of the images after transmission and to compare them with the correspondent ones acquired at the equipment console. To this aim, the AAs have identified all the parameters able to verify the quality level of the images and measured the values obtained for the directly acquired images and the transferred ones. They have also considered different kinds of transmission protocols to define suitable procedures of remote quality controls. (authors)

  5. Development of materials for fuel cell application by radiation technology

    International Nuclear Information System (INIS)

    The development of the single cell of SOFC with low operation temperature at and below 650 .deg. C(above 400 mW/cm2) Ο The development of fabrication method for the single cell of solid oxide fuel cell (SOFC) by dip-coating of nanoparticles such as NiO, YSZ, Ag, and Ag/C, etc. Ο The optimization of the preparation and performance of SOFC by using nanoparticles. Ο The preparation of samples for SOFC with large dimension. The development of fluoropolymer-based fuel cell membranes with crosslinked structure by radiation grafting technique Ο The development of fuel cell membranes with low methanol permeability via the introduction of novel monomers (e. g. vinylbenzyl chloride and vinylether chloride) by radiation grafting technique Ο The development of hydrocarbon fuel cell membrane by radiation crosslinking technique Ο The structure analysis and the evaluations of the property, performance, and radiation effect of the prepared membranes Ο The optimization of the preparation and performance of DMFC fuel cell membrane via the structure-property analysis (power: above 130 mW/cm2/50 cm2 at 5M methanol) Ο The preparation of samples for MEA stack assembly

  6. Radiation-induced motility alterations in medulloblastoma cells

    OpenAIRE

    Rieken, Stefan; Rieber, Juliane; Brons, Stephan; Habermehl, Daniel; Rief, Harald; Orschiedt, Lena; Lindel, Katja; Klaus J. Weber; Debus, Jürgen; Combs, Stephanie E

    2015-01-01

    Photon irradiation has been repeatedly suspected of increasing tumor cell motility and promoting locoregional recurrence of disease. This study was set up to analyse possible mechanisms underlying the potentially radiation-altered motility in medulloblastoma cells. Medulloblastoma cell lines D425 and Med8A were analyzed in migration and adhesion experiments with and without photon and carbon ion irradiation. Expression of integrins was determined by quantitative FACS analysis. Matrix metallop...

  7. Coniferyl Aldehyde Ameliorates Radiation Intestine Injury via Endothelial Cell Survival

    International Nuclear Information System (INIS)

    Cancer treatments related gastrointestinal toxicity has also been recognized as a significant economic burden. Especially, extensive apoptosis of microvascular endothelial cell of the lamina propria is the primary lesion initiating intestinal radiation damage after abdominal radiation therapy. Coniferyl aldehyde (CA) is phenolic compounds isolated from cork stoppers, and one of the major pyrolysis products of lignin. Shi H. was support for the empirical use of CA as a medicinal food for cardiovascular diseases. CA has positive effect in broad way but there is no consequence in radiation induced intestine damage. Here, we investigate effect of CA on small intestine after abdominal IR to mice in this study. In this study, CA increased the survival rate in C3H mice against 13.5 Gy abdominal IR. We found CA protects small intestine via preventing endothelial cell apoptosis and enhancing their angiogenic activity. CA also showed protective effect on crypt cell survival. Endothelial cell survival may affect crypt cell protection against IR. From this data, we concluded that CA is effective for protection against abdominal radiation injury. CA could ameliorate side-effect of radiation therapy

  8. Coniferyl Aldehyde Ameliorates Radiation Intestine Injury via Endothelial Cell Survival

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Ye Ji; Jung, Myung Gu; Lee, Yoonjin; Lee, Haejune [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Lee, Yunsil [Ewha Woman' s Univ., Seoul (Korea, Republic of); Ko, Younggyu [Korea Univ., Seoul (Korea, Republic of)

    2014-05-15

    Cancer treatments related gastrointestinal toxicity has also been recognized as a significant economic burden. Especially, extensive apoptosis of microvascular endothelial cell of the lamina propria is the primary lesion initiating intestinal radiation damage after abdominal radiation therapy. Coniferyl aldehyde (CA) is phenolic compounds isolated from cork stoppers, and one of the major pyrolysis products of lignin. Shi H. was support for the empirical use of CA as a medicinal food for cardiovascular diseases. CA has positive effect in broad way but there is no consequence in radiation induced intestine damage. Here, we investigate effect of CA on small intestine after abdominal IR to mice in this study. In this study, CA increased the survival rate in C3H mice against 13.5 Gy abdominal IR. We found CA protects small intestine via preventing endothelial cell apoptosis and enhancing their angiogenic activity. CA also showed protective effect on crypt cell survival. Endothelial cell survival may affect crypt cell protection against IR. From this data, we concluded that CA is effective for protection against abdominal radiation injury. CA could ameliorate side-effect of radiation therapy.

  9. Comparison of GSM Modulated and CW Radiofrequency Radiation on Cells

    International Nuclear Information System (INIS)

    The aim of our study was to evaluate and compare effect of global system of mobile (GSM) modulation and continuous wave (CW) radiofrequency radiation (RF) on proliferation ability and viability of V79 Chinese hamster lung cells. Previously prepared samples of cells in culture were exposed for 1, 2 and 3 hours both to 915 MHz GSM modulated and to 935 MHz CW RF field in gigahertz transversal electromagnetic mode cell (GTEM-cell). Electric field strength for cells exposed to GSM modulation was set at 10 V/m and for CW exposed cells was 8.2 V/m. Average specific absorption rate (SAR) was calculated to be for GSM 0.23 W/kg and for CW 0.12 W/kg. V79 samples were plated in concentration of 1x104cells/mL. Cell proliferation was determined by cell counts for each hour of exposure during five post-exposure days. Trypan blue exclusion test was used to determine cell viability. In comparison to control cell samples, proliferation of GSM irradiated cells showed significant decrease after 3 hours of exposure on the second and third post-exposure day. CW exposed cell samples showed significant decrease after 3 hours of exposure on the third post-exposure day. Viability of GSM and CW exposed cells did not significantly differ from matched control cell samples. Both applied RF fields have shown similar effect on cell culture growth, and cell viability of V79 cell line. In addition, applied GSM modulated RF radiation demonstrate bigger influence on proliferation of cells. (author)

  10. Radiation-induced spindle cell sarcoma: A rare case report

    Directory of Open Access Journals (Sweden)

    Khan Mubeen

    2009-01-01

    Full Text Available Ionizing radiation has been known to induce malignant transformation in human beings. Radiation-induced sarcomas are a late sequel of radiation therapy. Most sarcomas have been reported to occur after exposure to a radiation dose of 55 Gray (Gy and above, with a dose ranging from 16 to 112 Gys. Spindle cell sarcomas, arising after radiotherapy given to treat the carcinoma of head and neck region is a very uncommon sequel. This is a rare case report of spindle cell sarcoma of left maxilla, in a 24-year-old male, occurring as a late complication of radiotherapy with Cobalt-60 given for the treatment of retinoblastoma of the left eye 21 years back.

  11. Applications of the IAEA code of practice TRS-457 for establishing radiation qualities at the Syrian National Radiation Metrology Laboratory

    International Nuclear Information System (INIS)

    Syrian National Radiation Metrology Laboratory (NRML) has commissioned a new facility for diagnostic radiology and mammography calibrations. Two X-ray tubes were installed in order to carry on this task. First one is the ISO VOLT 160 Titan, maximum rating 160 kV and continuous rating 640/3000W tungsten anode. The second is side window tube 100 kV, 3000W molybdenum anode. Both were used to establish required radiation qualities in order to start calibration services in radiology field

  12. Quality of Intensity Modulated Radiation Therapy Treatment Plans Using a (60)Co Magnetic Resonance Image Guidance Radiation Therapy System

    DEFF Research Database (Denmark)

    Wooten, H Omar; Green, Olga; Yang, Min;

    2015-01-01

    PURPOSE: This work describes a commercial treatment planning system, its technical features, and its capabilities for creating (60)Co intensity modulated radiation therapy (IMRT) treatment plans for a magnetic resonance image guidance radiation therapy (MR-IGRT) system. METHODS AND MATERIALS: The...... clinical tolerances. CONCLUSIONS: A commercial (60)Co MR-IGRT device can produce highly conformal IMRT treatment plans similar in quality to linac IMRT for a variety of disease sites. Additional work is in progress to evaluate the clinical benefit of other novel features of this MR-IGRT system....

  13. Improvement of bacteriological quality of frozen chicken by gamma radiation

    International Nuclear Information System (INIS)

    The possible use of gamma irradiation at doses of 1.6 to 4.0 kGy to improve bacteriological quality of frozen chicken was investigated. The effects of gamma irradiation on salmonella viability in frozen chicken and on sensory quality of frozen chicken were also evaluated. D10-values for different isolated strains of salmonella in frozen chicken varied from 0.41 to 0.57 kGy. A dose of 4 kGy is required for a seven log cycle reduction of salmonella contamination in frozen chicken. Approximately 21 per cent of frozen chicken examined were contaminated with salmonella. Salmonella typhimurium, salmonella virchow, and salmonella java were predominant. Irradiation of frozen chicken at a minimum dose of 3.2 kGy eliminated salmonella, coliform, Escherichia coli, and Staphylococcus aureus and, in addition, reduced baterial load by 2 log cycles. Faecal streptococci was still present in a 3.2 kGy samples but in a very small percentage and the count was not over 100 colonies per g. Discoloring of chicken meat was noted after a 2 kGy treatment. The sensory quality of frozen chicken irradiated at 3 and 4 kGy tended to decrease during frozen storage but was within the acceptable range on a nine point hedonic scale even after eight months of frozen storage. Dosage at 3.2 kGy appeared to be sufficient for improving bacteriological quality of frozen chicken

  14. Objective evaluation of the quality of voice following radiation therapy for T1 glottic cancer

    International Nuclear Information System (INIS)

    Background: Radiation therapy is commonly considered the treatment of choice for T1 glottic cancer. While it is generally believed that the quality of voice following irradiation is quite satisfactory, few studies have reported the results of objective assessment of voice after radiation therapy. Purpose: To objectively evaluate the quality of voice following radiation therapy for T1 glottic cancer. Materials and methods: The voices of 12 patients treated for T1 glottic cancer with radiation therapy were evaluated by acoustic analysis and speech aerodynamic studies. Eleven patients received between 6300 and 6665 cGy at a daily fraction size of 180-225 cGy. One patient received 7000 cGy at a daily fraction size of 200 cGy. Evaluation of the quality of voice was done 3 months to 7 years following completion of radiation therapy. Results: The number of patients who scored abnormal values for the measurements of fundamental frequency, jitter, shimmer and harmonic to noise ratio was 2, 10, 4 and 3, respectively. The number of patients who scored abnormal values for transglottic airflow rate, subglottal pressure and glottal resistance was 12, 8 and 9, respectively. None of the studied patients scored normal values in all given tests. Conclusion: Although radiation therapy cures a high proportion of patients with T1 glottic cancer, the quality of voice does not return to normal following treatment

  15. Decreased sexual capacity after external radiation therapy for prostate cancer impairs quality of life

    International Nuclear Information System (INIS)

    Purpose: The aim of this study was to assess to what extent patients treated with radiation therapy for prostate cancer experience change in sexual functioning and to what extent this effects quality of life. Methods and Materials: Information was provided by 53 men treated with radiation therapy for localized prostate cancer. Assessment was made with the ''Radiumhemmets Scale of Sexual Functioning,'' which measures sexual desire, erectile capacity, orgasm, and to what extent a decrease in any of these aspects of sexual functioning affects quality of life. Function before treatment was assessed retrospectively. Results: Sexual desire diminished among 77% after treatment. The erection stiffness decreased in 77%. Before external radiation therapy, 66% had an erection usually sufficient for intercourse. Half of the men lost this ability after treatment. Of those retaining orgasm after treatment, 47% reported a decreased orgasmic pleasure and 91% a reduced ejaculation volume. Of all men, 50% reported that quality of life had decreased much or very much due to a decline in the erectile capacity following external radiation therapy. Conclusion: The results of the present study indicate that external radiation therapy for prostate cancer is associated with a reduction in sexual desire, erectile capacity, and orgasm functions. In a majority of patients this reduces quality of life. Previously, we may have underestimated the importance an intact sexual function has for the quality of life in this patient category of elderly men

  16. Functional genomics of UV radiation responses in human cells

    Energy Technology Data Exchange (ETDEWEB)

    Koch-Paiz, Christine A.; Amundson, Sally A.; Bittner, Michael L.; Meltzer, Paul S.; Fornace, Albert J

    2004-05-18

    The gene expression responses of MCF-7, a p53 wild-type (wt) human cell line, were monitored by cDNA microarray hybridization after exposure to different wavelengths of UV irradiation. Equitoxic doses of UVA, UVB, and UVC radiation were used to reduce survival to 37%. The effects of suramin, a signal pathway inhibitor, on the gene expression responses to the three UV wavelengths were also compared in this model system. UVB radiation triggered the broadest gene expression responses, and 172 genes were found to be consistently responsive in at least two-thirds of independent UVB experiments. These UVB radiation-responsive genes encode proteins with diverse cellular roles including cell cycle control, DNA repair, signaling, transcription, protein synthesis, protein degradation, and RNA metabolism. The set of UVB-responsive genes included most of the genes responding to an equitoxic dose of UVC radiation, plus additional genes that were not strongly triggered by UVC radiation. There was also some overlap with genes responding to an equitoxic dose of UVA radiation, although responses to this lower energy UV radiation were overall weaker. Signaling through growth factor receptors and other cytokine receptors was shown to have a major role in mediating UV radiation stress responses, as suramin, which inhibits such receptors, attenuated responses to UV radiation in nearly all the cases. Inhibition by suramin was greater for UVC than for UVB irradiation. This probably reflects the more prominent role in UVB damage response of signaling by reactive oxygen species, which would not be affected by suramin. Our results with suramin demonstrate the power of cDNA microarray hybridization to illuminate the global effects of a pharmacologic inhibitor on cell signaling.

  17. Effect of ionizing radiation on human skeletal muscle precursor cells

    OpenAIRE

    Marš, Tomaž; Čemažar, Maja; Jurdana, Mihaela; Pegan, Katarina

    2015-01-01

    Background. Long term effects of different doses of ionizing radiation on human skeletal muscle myoblast proliferation, cytokine signalling and stress response capacity were studied in primary cell cultures.Materials and methods. Human skeletal muscle myoblasts obtained from muscle biopsies were cultured and irradiated with a Darpac 2000 X-ray unit at doses of 4, 6 and 8 Gy. Acute effects of radiation were studied by interleukin - 6 (IL-6) release and stress response detected by the heat shoc...

  18. The effects of low doses of different radiation qualities on Vicia faba bean root meristems

    International Nuclear Information System (INIS)

    The effects of low doses of different radiation qualities have been investigated using the micronuclei induction in Vicia faba bean roots as an indicator. The radiation qualities used were: 60Co-gamma rays, high energy neutrons (maximum energy 600 MeV), low energy neutrons (mean energy 2.35 MeV), negative pions in the plateau region and negative pions in the stopping region. It was found that the best fit to the gamma ray data was obtained by using a linear+quadratic relationship, while in the case of the other radiation qualities a linear equation, represented the best fit, implying the non-existence of a threshold dose. No dose-rate, fractionation or oxygen effect was found for gamma radiation in the low dose region (below 20cGy) where the linear dependence between effect and dose is dominant. In contrast, in the high dose region these effects were present as normally expected. Fractionation experiments were carried out using high energy neutrons and pion radiation. No recovery was observed after neutron radiation while some recovery was found for the pion radiation. The RBE values found for the two neutron energies were in the high dose region 4.7 +- 0.4 and 11.8 +- 1.3. In the low dose region the RBE value approached a constant value of 25.4 +- 4.4 for the high energy neutrons and 63.7 +- 12.0 for the low energy neutrons. (orig./MG)

  19. Combination Effect of Nimotuzumab with Radiation in Colorectal Cancer Cells

    International Nuclear Information System (INIS)

    To investigate the radiosensitizing effect of the selective epidermal growth factor receptor (EGFR) inhibitor nimotuzumab in human colorectal cancer cell lines. Four human colorectal cancer cell lines, HCT-8, LoVo, WiDr, and HCT-116 were treated with nimotuzumab and/or radiation. The effects on cell proliferation, viability, and cell cycle progression were measured by MTT, clonogenic survival assay, flow cytometry, and Western blot. An immunoblot analysis revealed that EGFR phosphorylation was inhibited by nimotuzumab in colorectal cancer cell lines. Under these experimental conditions, pre-treatment with nimotuzumab increased radiosensitivity of colorectal cancer cell lines, except for cell line HCT-116. However, cell proliferation or cell cycle progression was not affected by the addition of nimotuzumab, irrespective of irradiation. Nimotuzumab enhanced the radiosensitivity of colorectal cancer cells in vitro by inhibiting EGFR-mediated cell survival signaling. This study provided a rationale for the clinical application of the selective EGFR inhibitor, nimotuzumab in combination with radiation in colorectal cancer cells.

  20. Combination Effect of Nimotuzumab with Radiation in Colorectal Cancer Cells

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Hye Kyung; Kim, Mi Sook; Jeong, Jae Hoon [Korea Institute of Radiologicaland Medical Sciences, Seoul (Korea, Republic of)

    2010-11-15

    To investigate the radiosensitizing effect of the selective epidermal growth factor receptor (EGFR) inhibitor nimotuzumab in human colorectal cancer cell lines. Four human colorectal cancer cell lines, HCT-8, LoVo, WiDr, and HCT-116 were treated with nimotuzumab and/or radiation. The effects on cell proliferation, viability, and cell cycle progression were measured by MTT, clonogenic survival assay, flow cytometry, and Western blot. An immunoblot analysis revealed that EGFR phosphorylation was inhibited by nimotuzumab in colorectal cancer cell lines. Under these experimental conditions, pre-treatment with nimotuzumab increased radiosensitivity of colorectal cancer cell lines, except for cell line HCT-116. However, cell proliferation or cell cycle progression was not affected by the addition of nimotuzumab, irrespective of irradiation. Nimotuzumab enhanced the radiosensitivity of colorectal cancer cells in vitro by inhibiting EGFR-mediated cell survival signaling. This study provided a rationale for the clinical application of the selective EGFR inhibitor, nimotuzumab in combination with radiation in colorectal cancer cells.

  1. Materials That Enhance Efficiency and Radiation Resistance of Solar Cells

    Science.gov (United States)

    Sun, Xiadong; Wang, Haorong

    2012-01-01

    A thin layer (approximately 10 microns) of a novel "transparent" fluorescent material is applied to existing solar cells or modules to effectively block and convert UV light, or other lower solar response waveband of solar radiation, to visible or IR light that can be more efficiently used by solar cells for additional photocurrent. Meanwhile, the layer of fluorescent coating material remains fully "transparent" to the visible and IR waveband of solar radiation, resulting in a net gain of solar cell efficiency. This innovation alters the effective solar spectral power distribution to which an existing cell gets exposed, and matches the maximum photovoltaic (PV) response of existing cells. By shifting a low PV response waveband (e.g., UV) of solar radiation to a high PV response waveband (e.g. Vis-Near IR) with novel fluorescent materials that are transparent to other solar-cell sensitive wavebands, electrical output from solar cells will be enhanced. This approach enhances the efficiency of solar cells by converting UV and high-energy particles in space that would otherwise be wasted to visible/IR light. This innovation is a generic technique that can be readily implemented to significantly increase efficiencies of both space and terrestrial solar cells, without incurring much cost, thus bringing a broad base of economical, social, and environmental benefits. The key to this approach is that the "fluorescent" material must be very efficient, and cannot block or attenuate the "desirable" and unconverted" waveband of solar radiation (e.g. Vis-NIR) from reaching the cells. Some nano-phosphors and novel organometallic complex materials have been identified that enhance the energy efficiency on some state-of-the-art commercial silicon and thin-film-based solar cells by over 6%.

  2. Radiation contributing to the space development. Radiation deterioration of space solar cell and its forecasting

    International Nuclear Information System (INIS)

    Radiation deterioration of the efficient triple-junction space solar cell (TSSC) recently developed and now put to practical use, is complicated due to its structure. This paper describes the characteristics of TSSC radiation deterioration and its forecast based radiological data. TSSC sub-cell has a 3-layered structure of InGaP surface light-receiving SC, GaAs middle SC and Ge back SC. TSSC panel is composed from layers of the cover glass to shield the radiation, of TSSC sub-cell, and of substrate plate panel of Al honeycomb core. Among the space radiation, the particular electron and proton particles that are of high energy, highly transmittable and much more abundant than other particles, mainly cause the deterioration of TSSC. The flux per unit time of those electron and proton depends on the position of the spacecraft because the particles are originated from the solar wind, trapped radiation and galactic cosmic rays, and thus the forecast of deterioration of TSSC is possible when the orbit of the committed craft is decided. Essential data of TSSC necessary for forecast are such as those of particle energy (MeV) vs conservation rate (power voltage ratio at the beginning/end of SC life under mimic sunlight), and vs relative damage coefficient, an indicator of conservation (deterioration). Highly efficient SC will be developed further and the concomitant forecasting technique will be required, for which development of radiation technology is also essential. (T.T.)

  3. Modification of radiation response in V79 cells with solcoseryl

    International Nuclear Information System (INIS)

    Solcoseryl is a deproteinized extract of calf serum which has been used for various purposes. It has been shown to simulate wound healing, to protect against carbon monoxide poisoning and to prevent teratogenic effects of cyclosphosphamide in mice. In addition, it has been reported to be a radiation protector and to modify radiation response in patients undergoing radiation treatment. The present study attempted to assess the effect of Solcoseryl on V79 cell survival and DNA damage after gamma irradiation. WR-1065 (4mM) was tested for comparative purpose. DNA damage was assayed using the alkaline elution technique while cell survival was determined in vitro using a standard clongenic assay. The results indicate that Solcoseryl doses protect against single-strand DNA breaks (SSB) but has little if any protective effect on cell survival. WR-1065- however, protects against both SSB and survival after gamma irradiation

  4. Signal transduction underlying ionizing radiation dose effects on cell growth

    International Nuclear Information System (INIS)

    Phosphorylation/dephosphorylation is commonly utilized in the irradiated cells to transmit intracellular information, such as that monitoring the severity of lesions, effectiveness of repair of damages, and fate of cells. Thus, the radiation dose effects on the flow of information through these intracellular networks should reveal the mechanisms underlying the cellular radiosensitivity, which needs to be monitored before performing radiation therapy on cancer patients. Antibodies that specifically recognize phosphorylated state of amino acids can be utilized to detect phosphorylation/dephosphorylation networks. It will be necessary to identify the antigenic proteins of the anti-phosphorylated amino acid antibody for further understanding. Mass spectrometry, which can determine the amino acid sequence of small peptide, will be important for this purpose. The radiation sensitivity measured by the flow of intracellular information will have general applications as a biomarker reflecting the state of homeostasis of cells in patients affected by various diseases or healthy aging individuals. (authors)

  5. In vitro cell culture lethal dose submitted to gamma radiation

    International Nuclear Information System (INIS)

    The present study was designed to evaluate the in vitro effect of gamma radiation in cell culture of mouse connective tissue exposed to different doses of gamma radiation and under several conditions. The cell viability was analyzed by neutral red uptake methodology. This assay was developed for establish a methodology to be used in the future in the study of resveratrol radioprotection. Resveratrol (3,4',5- trihydroxystilbene), a phenolic phytoalexin that occurs naturally in some spermatophytes, such as grapevines, in response to injury as fungal infections and exposure to ultraviolet light. In the wines this compound is found at high levels and is considered one of the highest antioxidant constituents. The intense antioxidant potential of resveratrol provides many pharmacological activities including cardioprotection, chemoprevention and anti-tumor effects. Our results demonstrated that 60Co gamma radiation lethal dose (LD50) on NCTC clone 929 cells was about 340Gy. (author)

  6. In vitro cell culture lethal dose submitted to gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, Carolina S.; Rogero, Sizue O.; Rogero, Jose Roberto [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: carolina_sm@hotmail.com; Ikeda, Tamiko I.; Cruz, Aurea S. [Instituto Adolfo Lutz, Sao Paulo, SP (Brazil)

    2009-07-01

    The present study was designed to evaluate the in vitro effect of gamma radiation in cell culture of mouse connective tissue exposed to different doses of gamma radiation and under several conditions. The cell viability was analyzed by neutral red uptake methodology. This assay was developed for establish a methodology to be used in the future in the study of resveratrol radioprotection. Resveratrol (3,4',5- trihydroxystilbene), a phenolic phytoalexin that occurs naturally in some spermatophytes, such as grapevines, in response to injury as fungal infections and exposure to ultraviolet light. In the wines this compound is found at high levels and is considered one of the highest antioxidant constituents. The intense antioxidant potential of resveratrol provides many pharmacological activities including cardioprotection, chemoprevention and anti-tumor effects. Our results demonstrated that {sup 60}Co gamma radiation lethal dose (LD50) on NCTC clone 929 cells was about 340Gy. (author)

  7. Quality control in radiotherapy treatment: Radiation induced myelopathy

    International Nuclear Information System (INIS)

    Direct injury of the spinal cord has been reported many times, particularly in cases of overexposures with radiotherapy of neoplasm that occurred outside the Central Nervous System. Permanent damage to the spinal cord is the most feared complication of radiation therapy treatments and one of the relatively common causes of litigation for medical malpractice in the context of cancer treatment. We have learned from clinical experience, data from randomized trials and animal experimentation, the dose tolerance as well as the interfraction interval for hyperfractionation regimes. We are still lacking precious clinical information, in particular the dose tolerance in combined modality treatments that represent the vast majority of modern treatments. (author)

  8. Microfabrication of high quality polytetrafluoroethylene films by synchrotron radiation

    International Nuclear Information System (INIS)

    We deposited polytetrafluoroethylene (PTFE) thin films both from the PTFE target by using synchrotron radiation (SR) beam and from PTFE emulsion by spin-coat process. The X-ray diffraction analyses showed a sharp peak due to (1 0 0) PTFE crystalline part, and only C-F2 bonding was found in Fourier transform infrared spectrophotometer spectra. From electron spectroscopy for chemical analysis measurements, no impurities were found. The fabricated PTFE films were easily etched by SR beam on the limited area of the surface on a microscale through a suitably patterned mask

  9. Accounting for radiation quality in heavy ion therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kellerer, A.M. [LMU, Muenchen (Germany). Radiobiological Inst.]|[Gesellschaft fuer Strahlen- und Umweltforschung, Muenchen (Germany). Inst. fuer Nuklearbiologie

    1997-09-01

    This introductory contribution outlines the need for models and their use in radiotherapy dose planning. The linear-quadratic dose relation is now predominantly used in therapy dose planning. In Section I it is linked to the earlier quantitative scheme for conventional radiotherapy. In Section II two major approaches are presented in a form that makes them comparable; the section can be read by itself, if this comparison alone is of interest. Models for therapy planning are tools, largely of empirical character; they do not need to elucidate unknown mechanisms of radiation action. The emphasis is, therefore, on the computational scheme, not on its interpretation. (orig.)

  10. Cellular automaton model of cell response to targeted radiation

    International Nuclear Information System (INIS)

    It has been shown that the response of cells to low doses of radiation is not linear and cannot be accurately extrapolated from the high dose response. To investigate possible mechanisms involved in the behaviour of cells under very low doses of radiation, a cellular automaton (CA) model was created. The diffusion and consumption of glucose in the culture dish were computed in parallel to the growth of cells. A new model for calculating survival probability was introduced; the communication between targeted and non-targeted cells was also included. Early results on the response of non-confluent cells to targeted irradiation showed the capability of the model to take account for the non-linear response in the low-dose domain

  11. Cell Phone Roulette and "Consumer Interactive" Quality

    Science.gov (United States)

    Navarro, Peter

    2005-01-01

    Under current policies, cell phone consumers face a lower probability of finding the best carrier for their usage patterns than winning at roulette. Corroborating survey data consistently show significant dissatisfaction among cell phone users, network performance is a major issue, and customer "churn" is high. This problem may be traced to a new…

  12. The process and promotion of radiation-induced cell death

    International Nuclear Information System (INIS)

    Radiation-induced cell death is divided into reproductive and interphase death, whose process can be revealed by time-lapse observations. Pedigree analyses of progenies derived from a surviving progenitor cell have shown that moribund cells appear in clusters among cells which are apparently undamaged (lethal sectoring). Sister cell fusion, which likely results from chromosome bridge, is the most frequently observed cell abnormality leading to reproductive death. While interphase death does not occur unless the dose exceeds 10 Gy for low LET radiation such as X-rays, high-LET radiation is very effective at inducing interphase death (RBE: ≅3 at 230 keV/μm). Expression or fixation of potentially lethal damage (PLD) is closely associated with cell cycle events and enhanced by inducing premature chromosome condensation (PCC) at a nonpermissive temperature in tsBN2 cells with a ts-defect in RCC1 protein (a regulator of chromatin condensation) which monitors the completion of DNA replication. Furthermore, higher-order structural changes in nuclear matrix such as induced by leptomycin B, an inhibitor of CRM1 (chromosome region maintenance) protein, also play an important role in the fixation of PLD. (author)

  13. A quality control program of radiation treatment in Hodgkin's disease

    International Nuclear Information System (INIS)

    The importance of the quality of radiotherapy for Hodgkin's disease has been stressed, particularly in specific American and german studies. A quality control program for verification of technical files for each patient was implemented during the EORTC H8 protocol for patients with a supra-diaphragmatic stage I and II Hodgkin's disease. Today, 161 technical files have been reviewed. while the definition of he target volumes were in accordance with the protocol for most of the patients, we observed 13.6 % of major deviations in terms of treated volumes, and 39.7 % of major deviations in terms of dose (for volumes, a number of deviations were in the cervical areas, where the upper limit of the field was lowered in view of protecting the parotids but the others were due to inadequate margins around the mediastinum and the hilum). Some of the dose deviations were due, in some cases, to the addition of a sub-carinal block after 30 Gy, but also, in cervical areas, in misinterpretation of the protocol. In conclusion, such a quality control program is justified by the number of major deviations which have been observed; it seems justified to carry out this program in the future H9 protocol. (authors)

  14. Safety in radiation therapy: quality assurance of computerized system

    International Nuclear Information System (INIS)

    The development of computerized systems in radiotherapy opens new challenging possibilities. There is however a major risk of specific errors if the use of such systems is not properly controlled. On the other hand, the software sophistication, such as encountered in modern treatment planning systems (TPS), makes it very difficult to set up efficient quality assurance programs compatible with the workload of users in charge of daily routine. From the analysis of previous accidents involving TPS, we can conclude that the major risks are erroneous calculations of monitor units resulting from a poor understanding of the software capabilities combined to a lack of vigilance with respect to the data obtained from a computer. To reduce the risks, it is necessary to setup a comprehensive quality assurance program covering all steps of the process, including commissioning of a new system and systematic checks of individual treatment plans. Such a program offers the users the opportunity to acquire a deeper understanding of the system and avoid potential pitfalls. There is presently a lack of consensus for an international protocol related to quality assurance of computerized systems in radiotherapy. It is therefore important to define protocols at the national level, with special consideration of the aspects which are more likely to generate significant errors. (author)

  15. Maintenance and improvement of dairy feed quality by radiation for distribution system

    International Nuclear Information System (INIS)

    With an aim to improve the quality of crude feed and its maintenance, γ-ray radiation was carried out during the steps of preparation and storage of feed and the effects on the fermentation of silage crude feed and mixed feed were investigated. Of the γ-ray radiation significant effects on general constituents in the silage were not observed immediately after the radiation, but it was clear that the contents of fibrous components were apt to increase one month later. The ratio, VBN/TN in the silage decreased with the elevation of radiation dose. Further it was found that radiation at 16 Gy or more is needed to prevent butyric acid fermentation in the silage and aerobic deterioration. In addition, the amount of peroxide lipids was not increased by the γ-radiation, suggesting that no adverse effects on the quality of the feed in silage might be caused by radiation. Thus, it was concluded that γ-radiation in appropriate conditions has favorable influence on silage fermentation. (M.N.)

  16. Sphingosine enhances apoptosis of radiation-resistant prostate cancer cells.

    Science.gov (United States)

    Nava, V E; Cuvillier, O; Edsall, L C; Kimura, K; Milstien, S; Gelmann, E P; Spiegel, S

    2000-08-15

    Ceramide has been implicated as an important component of radiation-induced apoptosis of human prostate cancer cells. We examined the role of the sphingolipid metabolites--ceramide, sphingosine, and sphingosine-1-phosphate--in susceptibility to radiation-induced apoptosis in prostate cancer cell lines with different sensitivities to gamma-irradiation. Exposure of radiation-sensitive TSU-Pr1 cells to 8-Gy irradiation led to a sustained increase in ceramide, beginning after 12 h of treatment and increasing to 2.5- to 3-fold within 48 h. Moreover, irradiation of TSU-Pr1 cells also produced a marked and rapid 50% decrease in the activity of sphingosine kinase, the enzyme that phosphorylates sphingosine to form sphingosine-1-phosphate. In contrast, the radiation-insensitive cell line, LNCaP, had sustained sphingosine kinase activity and did not produce elevated ceramide levels on 8-Gy irradiation. Although LNCaP cells are highly resistant to gamma-irradiation-induced apoptosis, they are sensitive to the death-inducing effects of tumor necrosis factor alpha, which also increases ceramide levels in these cells (K. Kimura et al., Cancer Res., 59: 1606-1614, 1999). Moreover, we found that although irradiation alone did not increase sphingosine levels in LNCaP cells, tumor necrosis factor alpha plus irradiation induced significantly higher sphingosine levels and markedly reduced intracellular levels of sphingosine-1-phosphate. The elevation of sphingosine levels either by exogenous sphingosine or by treatment with the sphingosine kinase inhibitor N,N-dimethylsphingosine induced apoptosis and also sensitized LNCaP cells to gamma-irradiation-induced apoptosis. Our data suggest that the relative levels of sphingolipid metabolites may play a role in determining the radiosensitivity of prostate cancer cells, and that the enhancement of ceramide and sphingosine generation could be of therapeutic value. PMID:10969794

  17. Radiation resistance of solar cells for space application, 1

    International Nuclear Information System (INIS)

    A 50-μm thick ultrathin silicon solar cell and a 280-μm thick high performance AlGaAs/GaAs solar cell with high radiation resistance have been recently developed by National Space Development Agency of Japan (NASDA). In order to study the radiation resistance of these cells, a joint research was carried out between Japan Atomic Energy Research Institute (JAERI) and NASDA from 1984 through 1987. In this research, the irradiation method of electron beams, the effects of the irradiation conditions on the deterioration of solar cells by electron beams, and the annealing effects of the radiation damage in solar cells were investigated. This paper is the first one of a series of reports of the joint research. In this paper, the space radiation environment which artificial satellites will encounter, the solar cells used, and the experimental methods are described. In addition to these, the results of the study on the irradiation procedure of electron beams are reported. In the study of the irradiation method of electron beams, three methods, that is, the fixed irradiation method, the moving irradiation method, and the spot irradiation method were examined. In the fixed irradiation method and moving one, stationary solar cells and solar cells moving by conveyer were irradiated by scanning electron beams, respectively. On the other hand, in the spot irradiation method, stationary solar cells were irradiated by non-scanning steady electron beams. It was concluded that the fixed irradiation method was the most proper method. In addition to this, in this study, some pieces of information were obtained with respect to the changes in the electrical characteristics of solar cells caused by the irradiation of electron beams. (author) 52 refs

  18. Cone Beam CT: radiation protection aspects and quality control

    International Nuclear Information System (INIS)

    The technology related to Cone Beam Computed Tomography (CBCT) give three-dimensional (3D) diagnostic results. It allows to give to the patient doses much lower than traditional TC technique. This type of equipment, introduced relatively recently, is rapidly spreading in the field of Radiology and in particular dental and maxillofacial and is meant to be used more and more frequently in clinical practice and in the coming years there will be an increase of radiological examinations performed with this technique. In January 2012 the ANPEQ formed, within the Permanent Commission's technical aspects of radiation protection-health ' the Working Party ' Cone Beam CT ' with the intention to draw up an operating report that provide guidelines for radiological protection of the operators and of the population, in full respect of the relevant operating areas by other operators, such as physicists, doctors etc. In the course of work it is proved the opportunity to share what worked with other associations dealing with radiation protection, AIFM (Associazione Italiana di Fisica Medica), AIRP (Associazione Italiana di Radioprotezione), AIRM (Associazione Italiana di Radioprotezione Medica), organising a joint Conference on CBCT which was held at pisa on March 1, 2013. This report collects most of the contributions presented by individual speakers who participated in the Conference, by then state of the art in this innovative method.

  19. Effect of Radiation Processing on Protein Quality of Certain Legumes

    International Nuclear Information System (INIS)

    The Effects of irradiation (dose levels of 5, 7.5 and 10 kGy) on nutritive characteristics of peas (Pisum satinum L), cow peas (Vigna unguiculata L.Walp), lentils (Lens culinaris Med), kidney beans (Phaseolus vulgaris L), and chickpeas (Cicer arietinurn L) were examined. Analyses included proximate composition, levels of anti-nutrients (phytic acid, tannins), available lysine (AL), in vitro protein digestibility (IVPD), and protein efficiency ratio (PER) in the growing rat. The results showed that moisture, crude protein, crude fat, crude fiber, and ash were unchanged by the irradiation. Radiation processing significantly (p<0.05) reduced the levels of phytic acid (PA), tannins (TN), and available lysine (AE). IVPD and PER were significantly enhanced in a dose-dependent manner, relative to unirradiated control samples, for all legumes. The data sets for each legume exhibited high correlation coefficients between radiation dose and PA, TN, AE, IVPD, and PER. These results demonstrate the benefits of irradiation on the nutritional properties of these legumes

  20. Seven cases of radiation-induced cutaneous squamous cell carcinoma

    International Nuclear Information System (INIS)

    We report 7 cases of radiation-induced skin cancer. The diagnosis was based on the history of radiotherapy for benign skin diseases (5 cases) and of occupational exposures to medical doctors (2 cases). All cases were squamous cell carcinomas which arose from chronic radiodermatitis. The estimated latent period of these tumors ranged from 6 to 64 years, with an average of 29.9 years. After surgical treatments of the lesions, no local recurrences were observed in all cases. Benign skin diseases had sometimes been treated with low-energy radiation before the 1960s. Considering the estimated latent period, the peak time point of developing risk of radiation-induced skin cancer by such treatment has been already passed, however, the danger of it should not be ignored in future. In association with multiplicity of radiation usage, occupational exposure of radiation may develop the risk of occurrence of skin cancer in future. Therefore, we should recognize that radiation-induced skin cancer is not in the past. In the cases of chronic skin diseases showing warty keratotic growth, erosion and ulcer, we should include chronic radio-dermatitis in the differential diagnosis. It is necessary to recall all patients about the history of radiotherapy or radiation exposure. Rapid histopathological examination is mandatory because of the suspicion of radiation-induced skin cancer. (author)

  1. Quality control and quality assurance in individual monitoring of ionising radiations

    International Nuclear Information System (INIS)

    This paper describes the programmes and approaches that are to be considered in developing and introducing quality assurance and quality control procedures in individual monitoring services. Quality assurance and quality control in individual monitoring services are essential to maintain quality and are of increasing importance in order to meet the requirements of national regulations and international standards and guidelines. It is recommended here that all organisations offering individual monitoring services should run their services based on the principles of Quality System as given in the European Standard EN45001 and maintain a property resources QA/QC programme as an integral part of their operations. All aspects of QA/QC in individual monitoring services starting from the initial selection, installation, calibration, and operation to the final products including dose reporting, dose record keeping, dealing with customers' complaints and product liability issues have been discussed. (Author)

  2. Characterization of diagnostic radiation qualities according to the IEC 61267 at LMRI-ITN

    International Nuclear Information System (INIS)

    The purpose of this work was to characterize the radiation qualities RQR, RQA and RQT, according to the international standard IEC 61267, to implement them in the Metrological Laboratory of Ionizing Radiation in the Nuclear and Technological Institute (LMRI - ITN) for the calibration of dosimeters used in diagnostic radiology. In this study was used the international standard IEC 61267(2005): Medical diagnostic X-ray equipment - Radiation conditions for use in the determination of characteristics, which is based on the determination of the half-value layer - HVL, to characterize the various radiation qualities. Besides the HVL value, the standard uses two other parameters, the homogeneity coefficient - h, and the quotient y(1st HVLIEC)/y(0)

  3. Strategy on quality assurance in radiation fields and calibration techniques at FRS of JAEA

    International Nuclear Information System (INIS)

    The FRS, Facility of Radiation Standards, of JAEA has been developing and supplying the fields of X-, gamma-, beta-rays and neutrons for calibrating the radiation measuring devices used for radiation protection monitoring since 1980. Much effort has been devoted in recent years toward the development of the neutron and gamma-ray fields using a 4 MV Van de Graaff accelerator. In November 2006, we just started to open the FRS radiation reference fields to national laboratories, private industry and academia. Almost the fields are traceable to national standards, but a laboratory quality assurance is not yet realized. We plan to obtain the calibration laboratory accreditation of JCSS, Japan Calibration Service System, which is based on ISO-17025. Furthermore, the quality assurance is planed to be extended to the international credibility in the future, and we hope to play a leading role in the calibration facilities in Asia. (author)

  4. Quality keeping and upgrading technique on delivery of raw fodder and so forth by using radiation

    International Nuclear Information System (INIS)

    This study aimed at examining chemical and microbiological changes of feed raw materials caused by γ-ray radiation and obtaining some fundamental informations for development of new preparation and storage technique using radiation. In previous results, it could be estimated that the γ-ray radiation showed an effect to protect quality decrease of the silage. In particular, a product with good chemical compositions and sheep fondness and excellent quality on blended silage with pasture and beer cake could be obtained. In 1997 fiscal year, on bean curd refuse with fast putrefaction, a relationship between time length from production to closed sealing for blended silage and quality after preparation was examined. (G.K.)

  5. Dosimetric systems developed in Brazil for the radiation processes quality control

    International Nuclear Information System (INIS)

    In order to apply new technologies to the industrial processing of materials aiming economy, efficiency, speed and high quality, ionizing radiation has been used in medicine, archaeology, chemistry, food preservation and other areas. For this reason, the dosimetry area looks for improve current dosimeters and develop new materials for application on quality control of these processes. In Brazil, the research in the dosimetry area occurs with great speed providing many different dosimetric systems. The chemical dosimetry is the most used technique in routine dosimetry, which requires fast and accurate responses. This technique involves determination of absorbed dose by measuring chemical changes radiation induced in the materials. Different dosimetric systems were developed at IPEN for application on radiation process quality and all of them present excellent results; the low cost of these materials allows a more effective dose control, therefore, a larger area or volume can be monitored. (author).

  6. Dosimetric systems developed in Brazil for the radiation processes quality control

    Energy Technology Data Exchange (ETDEWEB)

    Galante, Ana Maria Sisti; Campos, Leticia Lucente, E-mail: sgalante@ipen.b, E-mail: lcrodri@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    In order to apply new technologies to the industrial processing of materials aiming economy, efficiency, speed and high quality, ionizing radiation has been used in medicine, archaeology, chemistry, food preservation and other areas. For this reason, the dosimetry area looks for improve current dosimeters and develop new materials for application on quality control of these processes. In Brazil, the research in the dosimetry area occurs with great speed providing many different dosimetric systems. The chemical dosimetry is the most used technique in routine dosimetry, which requires fast and accurate responses. This technique involves determination of absorbed dose by measuring chemical changes radiation induced in the materials. Different dosimetric systems were developed at IPEN for application on radiation process quality and all of them present excellent results; the low cost of these materials allows a more effective dose control, therefore, a larger area or volume can be monitored. (author).

  7. Radiation-induced genetic effects in germ cells of mammals

    International Nuclear Information System (INIS)

    The objectives of the project are a better understanding of the fundamental principles that determine the radiation sensitivity in humans, with specific attention for the role of DNA repair in germ cells. The induction and repair of damage in DNA of germ cells of the Syrian golden hamster exposed to ionizing radiation is studied at biologically relevant doses. It has also been investigated which aspects of DNA sequence or chromosomal organisation are important with respect to their influence on the repairability of DNA damage. (R.P.) 10 refs

  8. TH-E-19A-01: Quality and Safety in Radiation Therapy

    International Nuclear Information System (INIS)

    Clinical radiotherapy data clearly demonstrate the link between the quality and safety of radiation treatments and the outcome for patients. The medical physicist plays an essential role in this process. To ensure the highest quality treatments, the medical physicist must understand and employ modern quality improvement techniques. This extends well beyond the duties traditionally associated with prescriptive QA measures. This session will review the current best practices for improving quality and safety in radiation therapy. General elements of quality management will be reviewed including: what makes a good quality management structure, the use of prospective risk analysis such as FMEA, and the use of incident learning. All of these practices are recommended in society-level documents and are incorporated into the new Practice Accreditation program developed by ASTRO. To be effective, however, these techniques must be practical in a resource-limited environment. This session will therefore focus on practical tools such as the newly-released radiation oncology incident learning system, RO-ILS, supported by AAPM and ASTRO. With these general constructs in mind, a case study will be presented of quality management in an SBRT service. An example FMEA risk assessment will be presented along with incident learning examples including root cause analysis. As the physicist's role as “quality officer” continues to evolve it will be essential to understand and employ the most effective techniques for quality improvement. This session will provide a concrete overview of the fundamentals in quality and safety. Learning Objectives: Recognize the essential elements of a good quality management system in radiotherapy. Understand the value of incident learning and the AAPM/ASTRO ROILS incident learning system. Appreciate failure mode and effects analysis as a risk assessment tool and its use in resource-limited environments. Understand the fundamental principles of good

  9. TH-E-19A-01: Quality and Safety in Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Ford, E [University of Washington, Seattle, WA (United States); Ezzell, G [Mayo Clinic Arizona, Phoenix, AZ (United States); Miller, B [Henry Ford Health System, Clinton Township, MI (United States); Yorke, E [Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

    2014-06-15

    Clinical radiotherapy data clearly demonstrate the link between the quality and safety of radiation treatments and the outcome for patients. The medical physicist plays an essential role in this process. To ensure the highest quality treatments, the medical physicist must understand and employ modern quality improvement techniques. This extends well beyond the duties traditionally associated with prescriptive QA measures. This session will review the current best practices for improving quality and safety in radiation therapy. General elements of quality management will be reviewed including: what makes a good quality management structure, the use of prospective risk analysis such as FMEA, and the use of incident learning. All of these practices are recommended in society-level documents and are incorporated into the new Practice Accreditation program developed by ASTRO. To be effective, however, these techniques must be practical in a resource-limited environment. This session will therefore focus on practical tools such as the newly-released radiation oncology incident learning system, RO-ILS, supported by AAPM and ASTRO. With these general constructs in mind, a case study will be presented of quality management in an SBRT service. An example FMEA risk assessment will be presented along with incident learning examples including root cause analysis. As the physicist's role as “quality officer” continues to evolve it will be essential to understand and employ the most effective techniques for quality improvement. This session will provide a concrete overview of the fundamentals in quality and safety. Learning Objectives: Recognize the essential elements of a good quality management system in radiotherapy. Understand the value of incident learning and the AAPM/ASTRO ROILS incident learning system. Appreciate failure mode and effects analysis as a risk assessment tool and its use in resource-limited environments. Understand the fundamental principles of good

  10. Accuracy of treatment planning and quality control of radiation therapy delivery

    International Nuclear Information System (INIS)

    Accurate radiation therapy delivery to the target volume depends on appropriate treatment planning, daily patient set-up with minimum localization errors and performed treatment equipments. The present report describes 1) acquisition of patient data by CT and transfers axial tomography, 2) physiological movements of target volume due to respiration and swallowing during irradiation and 3) quality control of radiation therapy delivery by detection of localization errors in daily set-up. (author)

  11. Quality assurance and radiation protection in medical exposures in Europe. A role model

    International Nuclear Information System (INIS)

    Medical exposures constitute the major source of ionizing radiation to which the world population is exposed to. Due to this fact, the European Community has implemented a number of agreements aimed at regulating these activities. For its part, Spain - through a series of Royal Ordinances - has developed a legal framework to broadly address not only Radiation Protection but medical exposure quality criteria as well. These regulations may be used as reference criteria to addressing same issues in our country

  12. Treatment of radiation syndrome with emphasis on stem cell implantation

    International Nuclear Information System (INIS)

    Within few years, the possibility that the human body contains cells that can repair and regenerate damaged and diseased tissue has gone from an unlikely proposition to a virtual certainty. Patients who have received doses of radiation in the potentially low to mid-lethal range (2-6 Gy) will have depression in bone-marrow function with cessation of blood-cell production leading to pancytopenia. Selection of cases for stem cell transplantation is based upon clinical signs and symptoms. Hematopoietic stem cell which produces blood cell progeny provides support for hematopoietic and other cells within the marrow, and has also been a focus for possible tissue repair. Another cell type termed mesenchymal or stromal also exists in the marrow. This cell provides support for hematopoietic and other cells within the marrow, and has also been a focus for possible tissue repair. Stem cells are obtained from bone marrow, peripheral blood, placental and umbilical cord blood, embryonic stem cells and embryonic germ cells. These cells have great potential for clinical research due to their potential to regenerate tissue. As well known, the cryo preservation process can store any cell type, particularly blood cells, for an indeterminate time. (author)

  13. Radiation induction of multiaberrant cells in Allium cepa L

    International Nuclear Information System (INIS)

    'Rogue' cells determined by human geneticists as the cells with many chromosome aberrations. The main enigma of this phenomenon is its levels are unexpected higher in many studies. Frequently, these cells emergence in human are linked with radiation or viruses. 'Rogue' cells supposed to be very important in mutagenesis, oncogenesis and even in evolution process. We use plant assay (Allium cepa L.) to analyze the induction of cells with many chromosome aberration of different types. Cytogenetic damage of gamma-irradiation as frequency of multiaberrant cells in the root tip cells of Allium was determined. The empiric numbers of cells with many aberrations were compared with those expected in theoretical distributions (Poisson, geometric and Pascal). The frequency of multiaberrant cells in root tip cells was increased up to 83,33 ± 10,76 % under gamma-irradiation in various doses. Gamma-irradiation induced more multiaberrant cells in A. cepa meristems than expected in theoretical distributions. We supposed dependency of chromosome aberrations origin in the same cell after irradiation. The data obtained elucidate that under gamma-irradiation accumulation of aberrations in aberrant cells are not random, the appearance of one aberration in cell induced the appearance of others in the same cell. (author)

  14. Workshop on measurement quality assurance for ionizing radiation: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Heath, J.A.; Swinth, K.L. [comps.

    1993-12-31

    This workshop was held to review the status of secondary level calibration accreditation programs, review related measurement accreditation programs, document lessons learned, and to present changes in programs due to new national priorities involving radioactivity measurements. Contents include: fundamentals of measurement quality assurance (MQA), standards for MQA programs; perspectives and policies; complete MQA programs; future MQA programs; QA/QC programs--radioactivity; QA/QC programs--dosimetry; laboratory procedures for QA/QC; in-house control of reference dosimetry laboratories; in-house controls of radioactivity laboratories; and poster session. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  15. Workshop on measurement quality assurance for ionizing radiation: Proceedings

    International Nuclear Information System (INIS)

    This workshop was held to review the status of secondary level calibration accreditation programs, review related measurement accreditation programs, document lessons learned, and to present changes in programs due to new national priorities involving radioactivity measurements. Contents include: fundamentals of measurement quality assurance (MQA), standards for MQA programs; perspectives and policies; complete MQA programs; future MQA programs; QA/QC programs--radioactivity; QA/QC programs--dosimetry; laboratory procedures for QA/QC; in-house control of reference dosimetry laboratories; in-house controls of radioactivity laboratories; and poster session. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database

  16. Combined Effects of Radiation and Mercury on PLHC-1 Cells

    International Nuclear Information System (INIS)

    It is inevitable for living objects to expose themselves to multiple factors present in the environment. The combined effect of multi-factors is hard to estimate and predict in advance. Especially factors harmful to organisms can synergistically interact with each other. When the effect of the combined action is greater than expected additivity, it is called synergism or supra-additivity. Ionizing radiation can cause cell death, mainly due to its ability to produce reactive oxygen species in cells. Mercury is one of widespread environmental pollutants which is known to have toxic effects on organisms. There are many reports indicating its genotoxic potential in a variety of aquatic species. Synergistic effects of radiation and mercury on human cells was previously reported. Aerobically growing organisms suffer from exposure to oxidative stress, caused by partially reduced forms of molecular oxygen, known as reactive oxygen species. These are highly reactive and capable of damaging cellular constituents such as DNA, lipids and proteins. Consequently, cells from many different organisms have evolved mechanisms to protect their components against reactive oxygen species. Reactive oxygen species can also be formed by exposure of cells either to ionizing radiation or redox cycling chemicals present in the environment like heavy metals. PLHC-1 hepatoma cell line derived from top minnow (Poeciliopsis lucida) is the most commonly used cell line in toxicology. The PLHC-1 cells are easy to cultivate, and can be used for screening the toxicity of chemicals. The present study was done to evaluate the combined effects of radiation with mercury chloride on the PLHC-1 cells

  17. Establishment of an X radiation equipment quality control programme using non invasive meters

    International Nuclear Information System (INIS)

    The objective of this work was to study the behavior of the mainly X ray equipment calibration laboratory of IPEN, operated in the range from 25 kV to 150 kV using a PTW non invasive meter, model DiavoltTM, and an ORTEC spectrometry system, model NOMAD-PLUS 92X, for the establishment of a quality control programme. The Diavolt meter was used for measurements of air kerma, peak voltage and practical peak voltage. The measurements were made varying parameters such as electrical current, X radiation quality for radiation diagnostic, angulations of the meter and its distance in relation to the focal spot of the X ray tube. The results were compared with data found in the literature. Several spectra were generated with the spectrometer system with the purpose of determine the peak voltage in function of the nominal voltage and to characterize the radiation qualities for radiation diagnostic previously determined. The established quality control programme enables the management of the appropriate functioning of the measurement instruments (ionization chambers, voltage and current meter and spectrometer) as well as of the X radiation system. This work also has proposed a time interval to run each one of the tests. (author)

  18. Autophagy contributes to resistance of tumor cells to ionizing radiation

    International Nuclear Information System (INIS)

    Background and purpose: Autophagy signaling is a novel important target to improve anticancer therapy. To study the role of autophagy on resistance of tumor cells to ionizing radiation (IR), breast cancer cell lines differing in their intrinsic radiosensitivity were used. Materials and methods: Breast cancer cell lines MDA-MB-231 and HBL-100 were examined with respect to clonogenic cell survival and induction of autophagy after radiation exposure and pharmacological interference of the autophagic process. As marker for autophagy the appearance of LC3-I and LC3-II proteins was analyzed by SDS-PAGE and Western blotting. Formation of autophagic vacuoles was monitored by immunofluorescence staining of LC3. Results: LC3-I and LC3-II formation differs markedly in radioresistant MDA-MB-231 versus radiosensitive HBL-100 cells. Western blot analyses of LC3-II/LC3-I ratio indicated marked induction of autophagy by IR in radioresistant MDA-MB-231 cells, but not in radiosensitive HBL-100 cells. Indirect immunofluorescence analysis of LC3-II positive vacuoles confirmed this differential effect. Pre-treatment with 3-methyladenine (3-MA) antagonized IR-induced autophagy. Likewise, pretreatment of radioresistant MDA-231 cells with autophagy inhibitors 3-MA or chloroquine (CQ) significantly reduced clonogenic survival of irradiated cells. Conclusion: Our data clearly indicate that radioresistant breast tumor cells show a strong post-irradiation induction of autophagy, which thus serves as a protective and pro-survival mechanism in radioresistance.

  19. Residual radiation effect in the murine hematopoietic stem cell compartment

    International Nuclear Information System (INIS)

    Stem cells surviving radiation injury may carry defects which contribute to long-term effects. The ratio of 125-iododeoxyuridine (IUdR) uptake into spleens of lethally irradiated recipient mice between day 3 and day 5 after cell transfusion revealed reduced proliferative ability (PF) of spleen seeding cells in parallel with reduced CFU-S content of donors throughout the study period of one year after 5 Gy gamma irradiation. Additional data aided in evaluating possible mechanisms of PF reduction. Within the range of the graft sizes used, PF was independent of the numbers of cells or CFU-S transfused. Radiation-induced increase in loss of label between days 3 and 5 and prolonged doubling time of proliferating cells indicated enhancement of cell maturation and increase in mitotic cycle time. Increased IUdR uptake per transfused CFUsub(S) suggested extra divisions of transit cells due to insufficiency in the stem cell compartment. It is concluded that persisting defects in surviving stem cells interfere in a complex way with cell proliferation in the hemopoietic system. (orig.)

  20. Problems in mechanistic theoretical models for cell transformation by ionizing radiation

    International Nuclear Information System (INIS)

    A mechanistic model based on yields of double strand breaks has been developed to determine the dose response curves for cell transformation frequencies. At its present stage the model is applicable to immortal cell lines and to various qualities (X-rays, Neon and Iron) of ionizing radiation. Presently, we have considered four types of processes which can lead to activation phenomena: (i) point mutation events on a regulatory segment of selected oncogenes, (ii) inactivation of suppressor genes, through point mutation, (iii) deletion of a suppressor gene by a single track, and (iv) deletion of a suppressor gene by two tracks. (author)

  1. [Radiation risk, health and quality of life: the medico-psychological and social-ecological aspects].

    Science.gov (United States)

    Davydov, B I; Ponomarenko, V A; Baluev, O T; Ushakov, I B

    1993-01-01

    Complexity and contradictoriness of the triplet life quality-health-risk gain particular acuity owing to the extensive and intensive nature of radiation and non-radiation risks in the modern technological society. Improvement of life standards issue new risks. Unavoidability of existing risks, emergence of new ones, and necessity of qualitative, first of all energetic, life maintenance come into conflict with the principles of ecological stability. The concept of life quality is in many respects irrational and in the future will largely hinge on traditions, ideological and religious maxims. PMID:8012301

  2. Psychology and quality of life in cancer patients on radiation therapy

    International Nuclear Information System (INIS)

    The object of this study is to investigate sociodemographic and clinical characteristics, psychology, self-esteem and quality of life in cancer patients on radiation therapy and to provide useful information for therapeutic approach to cancer patients on radiation therapy. The subjects were 36 patients who had been treated with radiation therapy and 20 normal people. Sociodemographic information and clinical characteristics of cancer patients on radiation therapy were investigated, and symptom checklist-90-revised, Rosenberg Self-esteem Scale for self esteem, World Health Organization Quality of Life Assessment Instrument for quality of life were administered to subjects. And Spearman's correlation analysis was used among these. The tendency of somatization, depression, anxiety and hostility in cancer group were significantly higher than normal group. Self esteem and quality of life in cancer group were significantly lower than normal group. No significant difference was found in comparison of psychology, self esteem and quality of life according to sociodemographic variables. Among clinical characteristics, in the presence of metastasis in cancer patients, the scores of anxiety, phobia and paranoid ideation were higher. In patients with pain, the score of somatization was higher. And in case of weight loss, the score of somatization was higher. The higher score of depression, anxiety and hostility were significantly associated with lower self-esteem. And higher score of somatization, depression, anxiety and hostility were significantly associated with lower quality of life. Understanding and management of psychological symptoms, such as somatization, depression, anxiety, and hostility, and pain control are necessary to improve quality of life in cancer patients on radiation therapy

  3. Psychology and quality of life in cancer patients on radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jong Chul; Chung, Woong Ki [Chonnam National University Hospital, Gwangju (Korea, Republic of)

    2004-12-15

    The object of this study is to investigate sociodemographic and clinical characteristics, psychology, self-esteem and quality of life in cancer patients on radiation therapy and to provide useful information for therapeutic approach to cancer patients on radiation therapy. The subjects were 36 patients who had been treated with radiation therapy and 20 normal people. Sociodemographic information and clinical characteristics of cancer patients on radiation therapy were investigated, and symptom checklist-90-revised, Rosenberg Self-esteem Scale for self esteem, World Health Organization Quality of Life Assessment Instrument for quality of life were administered to subjects. And Spearman's correlation analysis was used among these. The tendency of somatization, depression, anxiety and hostility in cancer group were significantly higher than normal group. Self esteem and quality of life in cancer group were significantly lower than normal group. No significant difference was found in comparison of psychology, self esteem and quality of life according to sociodemographic variables. Among clinical characteristics, in the presence of metastasis in cancer patients, the scores of anxiety, phobia and paranoid ideation were higher. In patients with pain, the score of somatization was higher. And in case of weight loss, the score of somatization was higher. The higher score of depression, anxiety and hostility were significantly associated with lower self-esteem. And higher score of somatization, depression, anxiety and hostility were significantly associated with lower quality of life. Understanding and management of psychological symptoms, such as somatization, depression, anxiety, and hostility, and pain control are necessary to improve quality of life in cancer patients on radiation therapy.

  4. Phototherapy appliances, their ultraviolet radiation and quality assurance of phototherapy; Terveydenhuollon laadunhallinta. Valohoitolaitteet, niiden UV- saeteily ja valohoitojen laadunvarmistus

    Energy Technology Data Exchange (ETDEWEB)

    Huurto, L.; Leszczynski, K.; Visuri, R.; Ylianttila, L.; Jokela, K. [Radiation and Nuclear Safety Authority, Helsinki (Finland)

    1998-12-31

    Artificial UV radiation (UVR) is used in the treatment of psoriasis and other skin diseases. Long term phototherapy is associated to increased risk of squamous cell carcinoma. This report gives a short review of biological effects of UVR and technical aspects of phototherapy units. The phototherapy units used in Finnish Central hospitals are described and the measured UVR dose rates of these units are presented. In addition, the UVR meters used in hospitals are described and the calibration factors are given for UVR dose rate measurements: Finally, recommendations are given for the quality assurance of photo-therapy units as well as for assessing UVR doses of patients. (orig.) 88 refs.

  5. Phototherapy appliances, their ultraviolet radiation and quality assurance of phototherapy. Terveydenhuollon laadunhallinta. Valohoitolaitteet, niiden UV- saeteily ja valohoitojen laadunvarmistus

    Energy Technology Data Exchange (ETDEWEB)

    Huurto, L.; Leszczynski, K.; Visuri, R.; Ylianttila, L.; Jokela, K. (Radiation and Nuclear Safety Authority, Helsinki (Finland))

    1998-01-01

    Artificial UV radiation (UVR) is used in the treatment of psoriasis and other skin diseases. Long term phototherapy is associated to increased risk of squamous cell carcinoma. This report gives a short review of biological effects of UVR and technical aspects of phototherapy units. The phototherapy units used in Finnish Central hospitals are described and the measured UVR dose rates of these units are presented. In addition, the UVR meters used in hospitals are described and the calibration factors are given for UVR dose rate measurements: Finally, recommendations are given for the quality assurance of photo-therapy units as well as for assessing UVR doses of patients. (orig.) 88 refs.

  6. Cancer Stem Cells, Cancer Cell Plasticity and Radiation Therapy

    OpenAIRE

    Vlashi, Erina; Pajonk, Frank

    2014-01-01

    Since the first prospective identification of cancer stem cells in solid cancers the cancer stem cell hypothesis has reemerged as a research topic of increasing interest. It postulates that solid cancers are organized hierarchically with a small number of cancer stem cells driving tumor growth, repopulation after injury and metastasis. They give rise to differentiated progeny, which lack these features. The model predicts that for any therapy to provide cure, all cancer stem cells have to be ...

  7. Quality keeping and upgrading technique on delivery of raw fodder and so forth by using radiation

    International Nuclear Information System (INIS)

    As most of aerobic bacteria, anaerobic spore bacteria, molds and yeasts died owing to 8 to 16 kGy of γ-ray irradiation, it was found that butyric acid fermentation and aerobic putrefaction in silage did not form. As the lactobacilli bringing good fermentation quality died as well at such radiation dose, on a case of a mixed silage using the dregs, in which lactic acid was present, quality of its fermentation was good. And, many informations on changes in fatty quality and yeast activity in the silage formed by irradiation could also be obtained. As the dregs had a large difference in physical and chemical components, quality after preparation of the silage was not uniform. Materials suitable for γ-ray irradiation and radiation dose suitable for each material was found to be clarified. (G.K.)

  8. Issue of national standards for radiation protection and quality assurance in the medical radiology. Final report

    International Nuclear Information System (INIS)

    The scope of the project is the issue of national standards for the medical radiology to provide standardized (DIN norms) radiation protection in Germany. Emerging new technologies for instance in the field of information processing and digital techniques are have to be adapted. The standards are supposed to allow the surveillance of medical radiological installations with respect to the technical performance, quality and radiation protection. The project is also aimed to enhance the influence on the European and international standardization and its harmonization (ISO, IEC, CEN, CENELEC) in the fields of radiation protection regulation and X-ray regulation.

  9. Radiation exposure and image quality in x-Ray diagnostic radiology physical principles and clinical applications

    CERN Document Server

    Aichinger, Horst; Joite-Barfuß, Sigrid; Säbel, Manfred

    2012-01-01

    The largest contribution to radiation exposure to the population as a whole arises from diagnostic X-rays. Protecting the patient from radiation is a major aim of modern health policy, and an understanding of the relationship between radiation dose and image quality is of pivotal importance in optimising medical diagnostic radiology. In this volume the data provided for exploring these concerns are partly based on X-ray spectra, measured on diagnostic X-ray tube assemblies, and are supplemented by the results of measurements on phantoms and simulation calculations.

  10. Pulsed fluoroscopy reduces radiation doses to patients and improves image quality

    International Nuclear Information System (INIS)

    Pulsed fluoroscopy is a relatively new technique offering considerable improvements in terms of radiation doses and image quality, as co pared to continuous fluroscopy. The radiation is applied in the form of intermittent X-ray flashes. The technique holds the potential of producing fluoroscopic images and stored images essentially improved in sharpness and contrast. The optimal technique has been found to be grid-controlled, pulsed image acquisition, as it offers advantages in terms of radiation dose application and control. (orig./CB)

  11. Application of the ROC method to assessment of image quality issues in mammography. Part 2. Comparative evaluation of image quality and radiation dose to thick body sections

    International Nuclear Information System (INIS)

    For the experimental comparative assessment reported, the following radiation qualities were compared for radiation dose applied and image quality: molydenum anode, 30mum molybdenum filter, X-ray tube potential differences of 26-32 kV; molybdenum anode, 25 mum rhodium filter, X-ray tube potential differences of 26-32 kV; tungsten anode, 50 mum rhodium filter, X-ray tube potential differences of 26-32 kV. The results show that in the differentiated assessment according to the various radiation qualities, significant deviations in imaging quality of the different detail types are possible. (orig./CB)

  12. Improvement of Microbiological Quality on of Cordyceps militaris Products by Gamma Radiation

    International Nuclear Information System (INIS)

    The purpose of this study was to investigate the effects of gamma radiation on Cordyceps militaris. Its capsule product and fruiting bodies were irradiated by gamma radiation at 10 kGy. Irradiated and non-irradiated samples were analyzed for microbiological quality, ferric reducing antioxidant potential (FRAP) and free radical scavenging activity (DPPH). The results indicated that radiation treatment significantly reduced microbial numeration. Total bacterial counts on the capsule product and fruiting body samples were reduced by gamma radiation from 109 to103 cfu/g and from 104 to < 10 cfu/g respectively. On the other hand, their antioxidant activity as determined by DPPH radical scavenging ability and ferric reducing antioxidant potential (FRAP) were not affected by the gamma radiation dose of 10 kGy. Cordycepin substance was not significantly decreased (p < 0.05) after irradiation.

  13. The underprotective features of the sediment quality criterion for fluoranthene in the presence of ultraviolet radiation

    International Nuclear Information System (INIS)

    The goal of this study was to evaluate the fluoranthene sediment quality criterion (SQC) for the protection of benthic organisms in the presence of ultraviolet (UV) radiation. The authors exposed the benthic amphipod Hyalella azteca to clean and fluoranthene-spiked sediments at the SQC concentration (620 microg/goc) in the presence or absence of UV radiation. When UV radiation was used the test-organisms showed signs of stress (slow response to physical disturbance) after 48 hrs. When comparing the data of adults vs. juveniles, the authors found that the adults were more sensitive. After 5 days of exposure 90% of the adults were dead vs. 62% of the juveniles. This could have been the result of greater exposure to UV radiation caused by a larger body surface area on the adults. Studies of the combined effects of fluoranthene contaminated sediments and UV radiation using benthic organisms indicate that the current fluoranthene SOC requires further examination

  14. Extending the C-V method of establishing MIS detector quality to mercuric iodide radiation detectors

    International Nuclear Information System (INIS)

    It has been observed that mercuric iodide capacitance measurements provide good indication about the quality of the crystal and its suitability as a room temperature radiation detector. Such capacitance / voltage measurements show a peak at low frequency. The sharpness of the peak is proportional to the quality of the crystal, and the peak is very similar to metal insulator semiconductor (MIS) capacitance curves. The paper proposes a model for the mercuric iodide capacitance. (author)

  15. Calibrations and evaluation of the quality assurance during 1999 at the National Laboratory for ionising radiation

    International Nuclear Information System (INIS)

    The Swedish Radiation Protection Institute is the National Laboratory for the dosimetric quantities kerma, absorbed dose and dose equivalent. The activity is based on established calibration procedures and a quality assurance program for the used standards. This report gives a brief summary of the calibrations performed during 1999 and a more detailed description and analysis of the quality assurance during this year. The report makes it easier to draw conclusions about the long-term stability and possible malfunctions

  16. On the potential impact of the newly proposed quality factors on space radiation protection

    Science.gov (United States)

    Wilson, John W.; Townsend, Lawrence W.; Cucinotta, Francis A.

    1987-01-01

    The recently proposed changes in the defined quality factor hold great potential for easing some of the protection requirements from electrons and protons in the near-Earth environment. At the same time, the high Linear Energy Transfer (LET) components play an even more important role which must be further evaluated. Several recommendations are made which need to be addressed before these new quality factors can be implemented into space radiation potection practice.

  17. Radiation-induced genetic effects in germ cells of mammals

    International Nuclear Information System (INIS)

    The aim of the project is to gain information on the effects of ionizing radiation on germ cells of rodents and primates as measured by induced chromosomal translocations. Different aspects of the very significant interspecies differences between the mouse and the rhesus monkey (Macaca mulatta) for translocation induction in spermatogonial stem cells were studied. In addition, possible mechanisms for the well established reduced transmission of induced mouse translocations were investigated. (R.P.) 6 refs

  18. Radiative efficiency of lead iodide based perovskite solar cells

    OpenAIRE

    Kristofer Tvingstedt; Olga Malinkiewicz; Andreas Baumann; Carsten Deibel; Snaith, Henry J.; Vladimir Dyakonov; Bolink, Henk J.

    2015-01-01

    The maximum efficiency of any solar cell can be evaluated in terms of its corresponding ability to emit light. We herein determine the important figure of merit of radiative efficiency for Methylammonium Lead Iodide perovskite solar cells and, to put in context, relate it to an organic photovoltaic (OPV) model device. We evaluate the reciprocity relation between electroluminescence and photovoltaic quantum efficiency and conclude that the emission from the perovskite devices is dominated by a...

  19. Loratadine dysregulates cell cycle progression and enhances the effect of radiation in human tumor cell lines

    Directory of Open Access Journals (Sweden)

    Cook John A

    2010-02-01

    Full Text Available Abstract Background The histamine receptor-1 (H1-antagonist, loratadine has been shown to inhibit growth of human colon cancer xenografts in part due to cell cycle arrest in G2/M. Since this is a radiation sensitive phase of the cell cycle, we sought to determine if loratadine modifies radiosensitivity in several human tumor cell lines with emphasis on human colon carcinoma (HT29. Methods Cells were treated with several doses of loratadine at several time points before and after exposure to radiation. Radiation dose modifying factors (DMF were determined using full radiation dose response survival curves. Cell cycle phase was determined by flow cytometry and the expression of the cell cycle-associated proteins Chk1, pChk1ser345, and Cyclin B was analyzed by western blot. Results Loratadine pre-treatment of exponentially growing cells (75 μM, 24 hours increased radiation-induced cytotoxicity yielding a radiation DMF of 1.95. However, treatment of plateau phase cells also yielded a DMF of 1.3 suggesting that mechanisms other than cell cycle arrest also contribute to loratadine-mediated radiation modification. Like irradiation, loratadine initially induced G2/M arrest and activation of the cell-cycle associated protein Chk1 to pChk1ser345, however a subsequent decrease in expression of total Chk1 and Cyclin B correlated with abrogation of the G2/M checkpoint. Analysis of DNA repair enzyme expression and DNA fragmentation revealed a distinct pattern of DNA damage in loratadine-treated cells in addition to enhanced radiation-induced damage. Taken together, these data suggest that the observed effects of loratadine are multifactorial in that loratadine 1 directly damages DNA, 2 activates Chk1 thereby promoting G2/M arrest making cells more susceptible to radiation-induced DNA damage and, 3 downregulates total Chk1 and Cyclin B abrogating the radiation-induced G2/M checkpoint and allowing cells to re-enter the cell cycle despite the persistence of

  20. Radiation properties and sound quality characteristics of refrigerator noise

    Science.gov (United States)

    Jeon, Jin Yong; Jeong, Jeong Ho; You, Jin

    2005-09-01

    The characteristics of refrigerator noise in an anechoic chamber and in an actual environment were investigated. In order to predict the noise propagation in real apartment house, room acoustic simulations and measurements using different types of refrigerators were conducted. The sound-pressure level of the refrigerator noise in the real living room was much higher than in the anechoic chamber. In addition, an allowable sound-pressure level for refrigerator noise was determined by auditory experiments. For the stimuli of auditory experiments, the dry source of refrigerator noise was presented using a loud speaker at the position of the refrigerator. When the result of the subjective evaluation was at the level 2 (the noise rarely aware but comfortable), in which sound pressure level was about 25 dB(A), 95% of people were satisfied with the refrigerator noise. A semantic differential test using various adjectives was also conducted to evaluate the sound quality of refrigerator noise.

  1. Radiation-induced motility alterations in medulloblastoma cells.

    Science.gov (United States)

    Rieken, Stefan; Rieber, Juliane; Brons, Stephan; Habermehl, Daniel; Rief, Harald; Orschiedt, Lena; Lindel, Katja; Weber, Klaus J; Debus, Jürgen; Combs, Stephanie E

    2015-05-01

    Photon irradiation has been repeatedly suspected of increasing tumor cell motility and promoting locoregional recurrence of disease. This study was set up to analyse possible mechanisms underlying the potentially radiation-altered motility in medulloblastoma cells. Medulloblastoma cell lines D425 and Med8A were analyzed in migration and adhesion experiments with and without photon and carbon ion irradiation. Expression of integrins was determined by quantitative FACS analysis. Matrix metalloproteinase concentrations within cell culture supernatants were investigated by enzyme-linked immunosorbent assay (ELISA). Statistical analysis was performed using Student's t-test. Both photon and carbon ion irradiation significantly reduced chemotactic medulloblastoma cell transmigration through 8-μm pore size membranes, while simultaneously increasing adherence to fibronectin- and collagen I- and IV-coated surfaces. Correspondingly, both photon and carbon ion irradiation downregulate soluble MMP9 concentrations, while upregulating cell surface expression of proadhesive extracellular matrix protein-binding integrin α5. The observed phenotype of radiation-altered motility is more pronounced following carbon ion than photon irradiation. Both photon and (even more so) carbon ion irradiation are effective in inhibiting medulloblastoma cell migration through downregulation of matrix metalloproteinase 9 and upregulation of proadhesive cell surface integrin α5, which lead to increased cell adherence to extracellular matrix proteins. PMID:25736470

  2. Radiation-induced motility alterations in medulloblastoma cells

    International Nuclear Information System (INIS)

    Photon irradiation has been repeatedly suspected of increasing tumor cell motility and promoting locoregional recurrence of disease. This study was set up to analyse possible mechanisms underlying the potentially radiation-altered motility in medulloblastoma cells. Medulloblastoma cell lines D425 and Med8A were analyzed in migration and adhesion experiments with and without photon and carbon ion irradiation. Expression of integrins was determined by quantitative FACS analysis. Matrix metalloproteinase concentrations within cell culture supernatants were investigated by enzyme-linked immunosorbent assay (ELISA). Statistical analysis was performed using Student's t-test. Both photon and carbon ion irradiation significantly reduced chemotactic medulloblastoma cell transmigration through 8-μm pore size membranes, while simultaneously increasing adherence to fibronectin- and collagen I- and IV-coated surfaces. Correspondingly, both photon and carbon ion irradiation downregulate soluble MMP9 concentrations, while upregulating cell surface expression of proadhesive extracellular matrix protein-binding integrin α5. The observed phenotype of radiation-altered motility is more pronounced following carbon ion than photon irradiation. Both photon and (even more so) carbon ion irradiation are effective in inhibiting medulloblastoma cell migration through downregulation of matrix metalloproteinase 9 and upregulation of proadhesive cell surface integrin α5, which lead to increased cell adherence to extracellular matrix proteins. (author)

  3. Coniferyl aldehyde attenuates radiation enteropathy by inhibiting cell death and promoting endothelial cell function.

    Directory of Open Access Journals (Sweden)

    Ye-Ji Jeong

    Full Text Available Radiation enteropathy is a common complication in cancer patients. The aim of this study was to investigate whether radiation-induced intestinal injury could be alleviated by coniferyl aldehyde (CA, an HSF1-inducing agent that increases cellular HSP70 expression. We systemically administered CA to mice with radiation enteropathy following abdominal irradiation (IR to demonstrate the protective effects of CA against radiation-induced gastrointestinal injury. CA clearly alleviated acute radiation-induced intestinal damage, as reflected by the histopathological data and it also attenuated sub-acute enteritis. CA prevented intestinal crypt cell death and protected the microvasculature in the lamina propria during the acute and sub-acute phases of damage. CA induced HSF1 and HSP70 expression in both intestinal epithelial cells and endothelial cells in vitro. Additionally, CA protected against not only the apoptotic cell death of both endothelial and epithelial cells but also the loss of endothelial cell function following IR, indicating that CA has beneficial effects on the intestine. Our results provide novel insight into the effects of CA and suggest its role as a therapeutic candidate for radiation-induced enteropathy due to its ability to promote rapid re-proliferation of the intestinal epithelium by the synergic effects of the inhibition of cell death and the promotion of endothelial cell function.

  4. Sesamol protects human embryonic kidney cells from radiation induced cell death: a potential radioprotective agent

    International Nuclear Information System (INIS)

    Radioprotectors are agents which reduce the radiation effects on cell when applied prior to exposure of radiation. In our earlier studies, we have demonstrated that sesamol protected DNA (plasmid and calf thymus) and V79 cells from radiation induced cell death and the effect was higher (DMF=2) in comparison to melatonin (DMF=1.3). This prompted us to study, sesamol mediated radioprotection in detail to understand the mechanism of action. We have chosen human embryonic kidney (HEK) cells to understand the mechanism of radioprotection. The HEK cells were treated with sesamol before exposure of g rays (60Co teletherapy, Bhabhatron II) in the radiation dose range 0-7 Gy for clonogenic survival. Toxicity, antioxidant enzyme activity other biochemical assays were performed. Flow cytometric analysis (FACS Calibre, BD, USA) was used to determine the apoptotic population and mitochondrial membrane potential (Rh 123, JC-1). ROS was determined using DCFHDA. Cell cycle analysis, caspase 3 activity and cytochrome C were also measured. Results suggested that sesamol protected HEK cells from cell death. The dose modifying factor for sesamol was 1.3, whereas the alpha protection factor was 2. Sesamol inhibited radiation induced cell cycle arrest in G2/M phase; ROS generation and depolarization of mitochondrial membrane potential and caspase-3 activity. Sesamol inhibited damage of critical cellular components (protein, lipids, membrane and amino acid) and maintained the redox status of cells. The results will be helpful in understanding the mechanistic aspects and development of sesamol based radioprotector. (author)

  5. Stem cells and radiation: effects in targeted and non-targeted cells

    International Nuclear Information System (INIS)

    The renewing tissues of the body are hierarchically organized and maintained by a small population of self-maintaining stem cells that are important targets for malignant transformation and also for gene therapy and tissue engineering approaches in regenerative medicine. Deleterious effects of toxic insults such as ionizing radiation may be due to stem cell death, with consequent loss of mature functional cells, or to stem cell damage that leads to aberrant responses to regulatory mechanisms. However, because the homeostatic regulation of these tissues is complex (involving intercellular signalling and cellular interactions that control cell proliferation, differentiation and death) radiation effects on stromal cells that perturb the microenvironmental control may also result in deleterious effects on the stem cell compartment. The rapidly developing fields of research investigating radiation-induced genomic instability and bystander effects also indicate that radiation effects on stem cells can be indirect. Although the non-targeted mechanisms responsible for bystander effects and the induction and maintenance of the inducible instability phenotype are not understood, inter-cellular signalling and free radical-mediated processes may be common features. Inter-cellular signalling and production of free radicals are also features of inflammatory responses; a recently identified indirect consequence of radiation with the potential for both persisting and bystander-mediated damage as well as for conferring a predisposition to malignancy. The production of clastogenic factors and their capacity for indirect cell damage after irradiation, the involvement of stromal cells in malignancy and bystander-mediated genetic instability may all reflect aspects of non-specific inflammatory-type responses to radiation-induced stress and injury. Recent investigations demonstrating that radiation-induced signalling processes are influenced by tissue-specific and genetic factors add

  6. Late rectal symptoms and quality of life after conformal radiation therapy for prostate cancer

    International Nuclear Information System (INIS)

    Background and purpose: This study was carried out in order to analyze the prevalence of late rectal and anal symptoms after conformal radiation therapy for prostate cancer and to assess their association with quality of life. Patients and methods: Two-hundred and forty nine patients were interviewed at 24-111 months after definitive conformal radiation therapy of localized prostate cancer with a median dose of 70 Gy. Rectal symptoms and fecal incontinence were evaluated with standardized questionnaires. Quality of life was assessed with the EORTC Quality of Life Questionnaire-C30 and the prostate cancer module PR25. Results: Rectal symptoms were mostly intermittent. Daily symptoms occurred in ≤5% of the patients. Incontinence was mostly mild with only 3% of the patients reporting daily incontinence episodes. Quality of life was comparable to that of the male German general population except that cognitive functioning and diarrhea were worse in the study population and pain was worse in the reference population. Global quality of life was associated with fecal incontinence, fecal urge, tenesmus, therapy for rectal symptoms and hormonal therapy for biochemical/clinical recurrence. Conclusions: Rectal symptoms and fecal incontinence after conformal radiation therapy for prostate cancer are mostly intermittent. Fecal incontinence, fecal urge and tenesmus are associated with lower global quality of life levels

  7. Radiation improves gene transfer into human ovarian carcinoma cells

    International Nuclear Information System (INIS)

    Purpose/Objective: Poor gene transfer is the major stumbling block to successful gene therapy today. We hypothesized that ionizing radiation might activate cellular recombination, and so improve stable gene transfer. During studies to quantitate radiation activated recombination, we also found that both plasmid and adenoviral vector transduction could be increased by irradiation. The studies presented here describe the effects of irradiation on gene transduction efficiency (both transient and stable transduction) in several human ovarian carcinoma lines, as a prelude to in vivo animal studies. Materials and Methods: The effect of irradiation on stable gene transfer efficiency was determined in human ovarian carcinoma cell lines (SKOV3, CAOV3 and PA1). Either irradiated or unirradiated cells were transfected with pRSVZ plasmid (containing a LacZ expression cassette) in either the supercoiled and linearized (XmnI) forms and β-galactosidase expression followed with time. Transfection efficiency was measured by flow cytometry following FDG staining at 0, 48, and 96 hours after irradiation. FDG is converted to a fluorescent metabolite by LacZ, and thus reflects the transfection efficiency of the LacZ containing vector. Vector quantitation was also performed by southern hybridization. Stable transduction efficiency was measured 14 -35 days after irradiation. Optimization of the time of irradiation with respect to transfection was performed. Since cells demonstrated increased stable recombination for as long as 96 hours after irradiation, continuous low dose rate and multiple radiation fractions were also tested. These experiments were repeated using the Ad5CMVlacZ. Dividing cells were exposed to Ad5CMVlacZ at an MOI of 0.1,1,5,10 and 100 to determine optimum transfection concentration. Transduction efficiency was again measured at various intervals to determine the radiation dose and interval post transfection which provides the maximum increase in transfection

  8. Cell phone roulette and “consumer interactive” quality

    OpenAIRE

    Peter Navarro

    2005-01-01

    Under current policies, cell phone consumers face a lower probability of finding the best carrier for their usage patterns than winning at roulette. Corroborating survey data consistently show significant dissatisfaction among cell phone users, network performance is a major issue, and customer “churn” is high. This problem may be traced to a new form of “consumer interactive” quality characteristic of emergent high technology products such as cell phone and broadband services. This problem i...

  9. Comprehensive audits of radiotherapy practices: A tool for quality improvement: Quality Assurance Team for Radiation Oncology (QUATRO)

    International Nuclear Information System (INIS)

    As part of a comprehensive approach to quality assurance (QA) in the treatment of cancer by radiation, an independent external audit (peer review) is important to ensure adequate quality of practice and delivery of treatment. Quality audits can be of various types and at various levels, either reviewing critical parts of the radiotherapy process (partial audits) or assessing the whole process (comprehensive audits). The IAEA has a long history of providing assistance for dosimetry (partial) audits in radiotherapy to its Member States. Together with the World Health Organization (WHO), it has operated postal audit programmes using thermoluminescence dosimetry (TLD) to verify the calibration of radiotherapy beams since 1969. Furthermore, it has developed a set of procedures for experts undertaking missions to radiotherapy hospitals in Member States for on-site review of dosimetry equipment, data and techniques, measurements and training of local staff. This methodology involves dosimetry and medical radiation physics aspects of the radiotherapy process without entering into clinical areas. The IAEA, through its technical cooperation programme, has received numerous requests from developing countries to perform comprehensive audits of radiotherapy programmes to assess the whole process. including aspects such as organization, infrastructure, and clinical and medical physics components. The objective of a comprehensive clinical audit is to review and evaluate thc quality of all of the components of the practice of radiotherapy at an institution, including its professional competence, with a view to quality improvement. A multidisciplinary team, comprising a radiation oncologist, a medical physicist and a radiotherapy technologist, carries out the audit. The present publication has been field tested by IAEA teams performing audits in radiotherapy programmes in hospitals in Africa, Asia, Europe and Latin America. Their comments, corrections and feedback have been taken

  10. MFISH analysis of irradiated human fibroblasts: a comparison among radiations with different quality in the low-dose range

    International Nuclear Information System (INIS)

    The present investigation aimed to characterise the shape of dose-response curve and determining the frequency distribution of various aberration types as a function of dose and radiation quality in AG01522 primary human fibroblasts in the 0.1- to 1-Gy dose range. For this purpose, the cells were irradiated with 7.7 and 28.5 keV μm-1 low-energy protons, 62 keV μm-1 4He2+ ions (LNL Radiobiology facility) or X rays and samples collected for 24-colour mFISH analysis. X rays and 7.7 keV μm-1 protons displayed a quadratic dose-response curve solely for total and simple exchanges, whereas for high-linear energy transfer radiations, a linear dose-response curve was observed for all the aberration categories, with the exception of complex exchanges. (authors)

  11. Toward automated quality assurance for intensity- modulated radiation therapy

    International Nuclear Information System (INIS)

    Purpose: To investigate whether high-quality, relatively inexpensive, document and transparency scanners used as densitometers are sufficiently quantitative for routine quality assurance (QA). Methods and Materials: The scanner we investigated used a linear amplifier, digitizing gray-scale images to 12-bit resolution with a user-selected spatial resolution of 0.170 mm2 pixels. To reduce Newton's rings artifacts, the standard glass platen was replaced by glass with an antireflective coating. Conversion of reading to transmission was conducted by permanently placing a calibrated photographic step tablet on the scanner platen. After conversion to light transmission, a zero-phase two-dimensional Wiener filter was used to reduce pixel-to-pixel signal variation. Light-scatter artifacts were removed by deconvolution of a measured light-spread kernel. The light-spread kernel artifacts were significant along the scanner's detector axis, but were insignificant along the scanning axis. Results: Pixel-to-pixel noise was better than 2% for optical densities, ranging from 0.4 to 2.0 and 0 to 2.7 for the unfiltered and filtered images, respectively. The document scanning system response was compared against a confocal scanning laser densitometer. A series of IMRT dose distribution and dose calibration film sets were scanned using the two scanners, and the measured dose was compared. The maximum mean and standard deviation of the measured dose difference between the document scanner and confocal scanner was 1.48% and 1.06%, respectively. Conclusion: While the document scanners are not as flexible as dedicated film densitometers, these results indicate that, using the intensity and scatter corrections, the system provides accurate and precise measurements up to an optical density of 2.0, sufficient for routine IMRT film QA. For some film types, this requires the reduction in monitor units to limit the dose delivered to the film. The user must be cautious that the delivered IMRT

  12. Development of a quality-based radiation protection program for a new high grade uranium mill

    International Nuclear Information System (INIS)

    COGEMA Resources Inc.'s (CRI's) operation at McClean Lake in northern Saskatchewan, Canada will process ores from the richest uranium ore deposits in the world. With the combination of high ore grades and stringent radiation requirements, new design features and a well documented quality-based radiation protection program are required for operating the uranium mill. The new McClean Lake uranium mill incorporates such features and program. The mill began operation in June 1999 and is currently licensed for an initial production capacity of six pounds U3O8 annually. The ore grades will vary up to 30% uranium. The mill design ensures that workers are separated from radioactive ore being processed through the use of a slurry handling and processing system that maximizes containment, with state-of-the-art shielding and ventilation features that protect workers against external gamma radiation, and airborne radioactive particles (radon progeny and radioactive dusts). The radiation protection program for the McClean Lake mill consists of a Radiation Protection Quality Assurance Program Manual (RPQAPM) and a series of supporting manuals, which altogether cover the 'key elements of successful health and safety management' identified in the International Commission on Radiological Protection (ICRP, 1997), Publication 75: i.e., policy and organization, planning and implementation, measuring and reviewing performance'. As lead document, the PRQAPM outlines the quality assurance administration for the program: e.g., policy statement; management review; organization and authority; staff qualifications and training; change management and non-conformities; classification of radiation areas and nuclear energy worker designation; program information; and compliance. The RPQAPM also outlines the key program elements: i.e., monitoring worker radiation doses and workplace radiological levels, monitoring ventilation, equipment protocols, management , management of radioisotopes

  13. Transmission of clonal chromosomal abnormalities in human hematopoietic stem and progenitor cells surviving radiation exposure

    International Nuclear Information System (INIS)

    Highlights: • Radiation induced formation and transmission of chromosomal aberrations were assessed. • Cytogenetic analysis was performed in human CD34+ HSPC by mFISH. • We report transmission of stable aberrations in irradiated, clonally expanded HSPC. • Unstable aberrations in clonally expanded HSPC occur independently of irradiation. • Carbon ions and X-rays bear a similar risk for propagation of cytogenetic changes. - Abstract: In radiation-induced acute myeloid leukemia (rAML), clonal chromosomal abnormalities are often observed in bone marrow cells of patients, suggesting that their formation is crucial in the development of the disease. Since rAML is considered to originate from hematopoietic stem and progenitor cells (HSPC), we investigated the frequency and spectrum of radiation-induced chromosomal abnormalities in human CD34+ cells. We then measured stable chromosomal abnormalities, a possible biomarker of leukemia risk, in clonally expanded cell populations which were grown for 14 days in a 3D-matrix (CFU-assay). We compared two radiation qualities used in radiotherapy, sparsely ionizing X-rays and densely ionizing carbon ions (29 and 60–85 keV/μm, doses between 0.5 and 4 Gy). Only a negligible number of de novo arising, unstable aberrations (≤0.05 aberrations/cell, 97% breaks) were measured in the descendants of irradiated HSPC. However, stable aberrations were detected in colonies formed by irradiated HSPC. All cells of the affected colonies exhibited one or more identical aberrations, indicating their clonal origin. The majority of the clonal rearrangements (92%) were simple exchanges such as translocations (77%) and pericentric inversions (15%), which are known to contribute to the development of rAML. Carbon ions were more efficient in inducing cell killing (maximum of ∼30–35% apoptotic cells for 2 Gy carbon ions compared to ∼25% for X-rays) and chromosomal aberrations in the first cell-cycle after exposure (∼70% and ∼40

  14. Transmission of clonal chromosomal abnormalities in human hematopoietic stem and progenitor cells surviving radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Kraft, Daniela, E-mail: d.kraft@gsi.de [GSI Helmholtz Center for Heavy Ion Research, Department of Biophysics, Planckstr. 1, 64291 Darmstadt (Germany); Institute for Transfusion Medicine und Immunohematology, DRK-Blutspendedienst Baden-Wuerttemberg—Hessen, Johann Wolfgang Goethe-University Hospital, Sandhofstrasse 1, 60528 Frankfurt (Germany); Ritter, Sylvia, E-mail: s.ritter@gsi.de [GSI Helmholtz Center for Heavy Ion Research, Department of Biophysics, Planckstr. 1, 64291 Darmstadt (Germany); Durante, Marco, E-mail: m.durante@gsi.de [GSI Helmholtz Center for Heavy Ion Research, Department of Biophysics, Planckstr. 1, 64291 Darmstadt (Germany); Institute for Condensed Matter Physics, Physics Department, Technical University Darmstadt, Hochschulstraße 6-8, 64289 Darmstadt (Germany); Seifried, Erhard, E-mail: e.seifried@blutspende.de [Institute for Transfusion Medicine und Immunohematology, DRK-Blutspendedienst Baden-Wuerttemberg—Hessen, Johann Wolfgang Goethe-University Hospital, Sandhofstrasse 1, 60528 Frankfurt (Germany); Fournier, Claudia, E-mail: c.fournier@gsi.de [GSI Helmholtz Center for Heavy Ion Research, Department of Biophysics, Planckstr. 1, 64291 Darmstadt (Germany); Tonn, Torsten, E-mail: t.tonn@blutspende.de [Institute for Transfusion Medicine und Immunohematology, DRK-Blutspendedienst Baden-Wuerttemberg—Hessen, Johann Wolfgang Goethe-University Hospital, Sandhofstrasse 1, 60528 Frankfurt (Germany); Technische Universität Dresden, Med. Fakultät Carl Gustav Carus, Institute for Transfusion Medicine Dresden, German Red Cross Blood Donation Service North-East, Blasewitzer Straße 68/70, 01307 Dresden (Germany)

    2015-07-15

    Highlights: • Radiation induced formation and transmission of chromosomal aberrations were assessed. • Cytogenetic analysis was performed in human CD34+ HSPC by mFISH. • We report transmission of stable aberrations in irradiated, clonally expanded HSPC. • Unstable aberrations in clonally expanded HSPC occur independently of irradiation. • Carbon ions and X-rays bear a similar risk for propagation of cytogenetic changes. - Abstract: In radiation-induced acute myeloid leukemia (rAML), clonal chromosomal abnormalities are often observed in bone marrow cells of patients, suggesting that their formation is crucial in the development of the disease. Since rAML is considered to originate from hematopoietic stem and progenitor cells (HSPC), we investigated the frequency and spectrum of radiation-induced chromosomal abnormalities in human CD34{sup +} cells. We then measured stable chromosomal abnormalities, a possible biomarker of leukemia risk, in clonally expanded cell populations which were grown for 14 days in a 3D-matrix (CFU-assay). We compared two radiation qualities used in radiotherapy, sparsely ionizing X-rays and densely ionizing carbon ions (29 and 60–85 keV/μm, doses between 0.5 and 4 Gy). Only a negligible number of de novo arising, unstable aberrations (≤0.05 aberrations/cell, 97% breaks) were measured in the descendants of irradiated HSPC. However, stable aberrations were detected in colonies formed by irradiated HSPC. All cells of the affected colonies exhibited one or more identical aberrations, indicating their clonal origin. The majority of the clonal rearrangements (92%) were simple exchanges such as translocations (77%) and pericentric inversions (15%), which are known to contribute to the development of rAML. Carbon ions were more efficient in inducing cell killing (maximum of ∼30–35% apoptotic cells for 2 Gy carbon ions compared to ∼25% for X-rays) and chromosomal aberrations in the first cell-cycle after exposure (∼70% and

  15. Evaluation of Health Related Quality of Life in Patient with Oral Cavity Squamous Cell Carcinoma Receiving Chemotherapy

    OpenAIRE

    Mistry CB; Rana DS; Batra V

    2015-01-01

    Objective: To evaluate impact of chemotherapy on Health Related Quality of Life (HRQOL) in patients of oral cavity squamous cell carcinoma (OCSCC) by analysis of two different treatments named Concurrent Chemo - Radiation (CTRT) and Neo-Adjuvant Chemotherapy (NACT). Study Design and Instrument: Prospective longitudinal study by evaluation HRQOL by general quality of life (QLQC30) and head & neck specific (QLQ-H&N35) questionnaires of the European Organization for Res...

  16. Radiation disinfestation of fruits. Effectiveness and fruit quality

    International Nuclear Information System (INIS)

    The effectiveness of deactivating mature Mediterranean fruit fly, Ceratitis capitata (Wiedemann), eggs with gamma irradiation treatment at 500-600 Gy in several varieties of California peaches and nectarines was demonstrated. Small percentages of hatching and pupation occurred in plums, cherries and other varieties of peaches and nectarines after treatment at 600 Gy, but no adult eclosion was found. The higher dose may present an opportunity of making a difference in the marketability of some of the treated fruits, as compared with irradiation at a minimum of 150 Gy allowed as a quarantine treatment procedure. If larvae were found in the treated fruits upon arrival, quarantine officials may have to decide whether or not to release such a shipment. Combined treatment of papayas with heat, non-toxic chemical solutions and irradiation as a possible quarantine treatment did not result in synergism because of scalding of the fruit's skin. The quality of California stone fruits and ''Valencia'' oranges was retained after irradiation at doses between 300 and 750 Gy, with minor differences in the controls, probably attributable to a certain degree of delayed ripening in some fruits. (author). 24 refs, 7 tabs

  17. Differential effect of baicalein on ionizing radiation induced cell death in normal lymphocytes and lymphoma cells

    International Nuclear Information System (INIS)

    Baicalein (5,6,7-trihydroxy-2-phenyl-4H-1-benzopyran-4-one), a naturally occurring flavone, present in Indian and Chinese medicinal plants has been reported to possess potent antioxidant activity. Previous reports from our laboratory have elucidated the radical scavenging and radioprotective potential of this compound in cell free system. To investigate potential of baicalein as a radioprotector, we have studied its effect on normal lymphocytes and lymphoma cells (EL-4 cells) in presence of radiation. Baicalein protected murine splenic lymphocytes against radiation (4Gy) induced apoptosis as assessed by propidium iodide staining. It inhibited background cell death in lymphocytes whereas, baicalein induced concentration dependent cell death in EL-4 cells and did not protect against radiation induced apoptosis. Interestingly, baicalein scavenged radiation derived ROS (reactive oxygen species) in both the cell types suggesting that, it is not exhibiting differential antioxidant action. Despite scavenging radiation derived ROS, which are principal mediators of radiation induced cell death, baicalein induced cell death in EL-4 cells. To investigate the reason for this differential behavior, we investigated the effect of baicalein on pro-survival molecules viz. ERK and NF-kB. Baicalein induced phosphorylation of ERK in normal lymphocytes in a time dependent manner, but, it did not alter pERK levels in EL-4 cells. Baicalein treatment per se induced degradation of IkBα and increased nuclear accumulation of NF-kB in normal lymphocytes. Whereas, baicalein pre-treatment reduced basal NF-kB levels in EL-4 cells and it also suppressed TNF-α induced nuclear accumulation of NF-kB. This study suggests that, differential regulation of pro-survival transcription factor NF-kB may be playing a role in differential effect of baicalein in normal lymphocytes and lymphoma cells. (author)

  18. Mesenchymal Stem Cells Retain Their Defining Stem Cell Characteristics After Exposure to Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Nicolay, Nils H., E-mail: n.nicolay@dkfz.de [Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg (Germany); Department of Molecular and Radiation Oncology, German Cancer Research Center, Heidelberg (Germany); Sommer, Eva; Lopez, Ramon; Wirkner, Ute [Department of Molecular and Radiation Oncology, German Cancer Research Center, Heidelberg (Germany); Trinh, Thuy [Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg (Germany); Department of Molecular and Radiation Oncology, German Cancer Research Center, Heidelberg (Germany); Sisombath, Sonevisay [Department of Molecular and Radiation Oncology, German Cancer Research Center, Heidelberg (Germany); Debus, Jürgen [Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg (Germany); Ho, Anthony D.; Saffrich, Rainer [Department of Hematology and Oncology, Heidelberg University Hospital, Heidelberg (Germany); Huber, Peter E. [Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg (Germany); Department of Molecular and Radiation Oncology, German Cancer Research Center, Heidelberg (Germany)

    2013-12-01

    Purpose: Mesenchymal stem cells (MSCs) have the ability to migrate to lesion sites and undergo differentiation into functional tissues. Although this function may be important for tissue regeneration after radiation therapy, the influence of ionizing radiation (IR) on cellular survival and the functional aspects of differentiation and stem cell characteristics of MSCs have remained largely unknown. Methods and Materials: Radiation sensitivity of human primary MSCs from healthy volunteers and primary human fibroblast cells was examined, and cellular morphology, cell cycle effects, apoptosis, and differentiation potential after exposure to IR were assessed. Stem cell gene expression patterns after exposure to IR were studied using gene arrays. Results: MSCs were not more radiosensitive than human primary fibroblasts, whereas there were considerable differences regarding radiation sensitivity within individual MSCs. Cellular morphology, cytoskeletal architecture, and cell motility were not markedly altered by IR. Even after high radiation doses up to 10 Gy, MSCs maintained their differentiation potential. Compared to primary fibroblast cells, MSCs did not show an increase in irradiation-induced apoptosis. Gene expression analyses revealed an upregulation of various genes involved in DNA damage response and DNA repair, but expression of established MSC surface markers appeared only marginally influenced by IR. Conclusions: These data suggest that human MSCs are not more radiosensitive than differentiated primary fibroblasts. In addition, upon photon irradiation, MSCs were able to retain their defining stem cell characteristics both on a functional level and regarding stem cell marker expression.

  19. Mesenchymal Stem Cells Retain Their Defining Stem Cell Characteristics After Exposure to Ionizing Radiation

    International Nuclear Information System (INIS)

    Purpose: Mesenchymal stem cells (MSCs) have the ability to migrate to lesion sites and undergo differentiation into functional tissues. Although this function may be important for tissue regeneration after radiation therapy, the influence of ionizing radiation (IR) on cellular survival and the functional aspects of differentiation and stem cell characteristics of MSCs have remained largely unknown. Methods and Materials: Radiation sensitivity of human primary MSCs from healthy volunteers and primary human fibroblast cells was examined, and cellular morphology, cell cycle effects, apoptosis, and differentiation potential after exposure to IR were assessed. Stem cell gene expression patterns after exposure to IR were studied using gene arrays. Results: MSCs were not more radiosensitive than human primary fibroblasts, whereas there were considerable differences regarding radiation sensitivity within individual MSCs. Cellular morphology, cytoskeletal architecture, and cell motility were not markedly altered by IR. Even after high radiation doses up to 10 Gy, MSCs maintained their differentiation potential. Compared to primary fibroblast cells, MSCs did not show an increase in irradiation-induced apoptosis. Gene expression analyses revealed an upregulation of various genes involved in DNA damage response and DNA repair, but expression of established MSC surface markers appeared only marginally influenced by IR. Conclusions: These data suggest that human MSCs are not more radiosensitive than differentiated primary fibroblasts. In addition, upon photon irradiation, MSCs were able to retain their defining stem cell characteristics both on a functional level and regarding stem cell marker expression

  20. Establishing and Delivering Quality Radiation Therapy in Resource-Constrained Settings: The Story of Botswana.

    Science.gov (United States)

    Efstathiou, Jason A; Heunis, Magda; Karumekayi, Talkmore; Makufa, Remigio; Bvochora-Nsingo, Memory; Gierga, David P; Suneja, Gita; Grover, Surbhi; Kasese, Joseph; Mmalane, Mompati; Moffat, Howard; von Paleske, Alexander; Makhema, Joseph; Dryden-Peterson, Scott

    2016-01-01

    There is a global cancer crisis, and it is disproportionately affecting resource-constrained settings, especially in low- and middle-income countries (LMICs). Radiotherapy is a critical and cost-effective component of a comprehensive cancer control plan that offers the potential for cure, control, and palliation of disease in greater than 50% of patients with cancer. Globally, LMICs do not have adequate access to quality radiation therapy and this gap is particularly pronounced in sub-Saharan Africa. Although there are numerous challenges in implementing a radiation therapy program in a low-resource setting, providing more equitable global access to radiotherapy is a responsibility and investment worth prioritizing. We outline a systems approach and a series of key questions to direct strategy toward establishing quality radiation services in LMICs, and highlight the story of private-public investment in Botswana from the late 1990s to the present. After assessing the need and defining the value of radiation, we explore core investments required, barriers that need to be overcome, and assets that can be leveraged to establish a radiation program. Considerations addressed include infrastructure; machine choice; quality assurance and patient safety; acquisition, development, and retention of human capital; governmental engagement; public-private partnerships; international collaborations; and the need to critically evaluate the program to foster further growth and sustainability. PMID:26578607

  1. Radiation-induced autophagy promotes esophageal squamous cell carcinoma cell survival via the LKB1 pathway.

    Science.gov (United States)

    Lu, Chi; Xie, Conghua

    2016-06-01

    Radiotherapy is an important treatment modality for esophageal cancer; however, the clinical efficacy of radiotherapy is limited by tumor radioresistance. In the present study, we explored the hypothesis that radiation induces tumor cell autophagy as a cytoprotective adaptive response, which depends on liver kinase B1 (LKB1) also known as serine/threonine kinase 11 (STK11). Radiation-induced Eca-109 cell autophagy was found to be dependent on signaling through the LKB1 pathway, and autophagy inhibitors that disrupted radiation-induced Eca-109 cell autophagy increased cell cycle arrest and cell death in vitro. Inhibition of autophagy also reduced the clonogenic survival of the Eca-109 cells. When treated with radiation alone, human esophageal carcinoma xenografts showed increased LC3B and p-LKB1 expression, which was decreased by the autophagy inhibitor chloroquine. In vivo inhibition of autophagy disrupted tumor growth and increased tumor apoptosis when combined with 6 Gy of ionizing radiation. In summary, our findings elucidate a novel mechanism of resistance to radiotherapy in which radiation-induced autophagy, via the LKB1 pathway, promotes tumor cell survival. This indicates that inhibition of autophagy can serve as an adjuvant treatment to improve the curative effect of radiotherapy. PMID:27109915

  2. Radiation quality and ion-beam therapy: understanding the users' needs

    International Nuclear Information System (INIS)

    Ion-beam therapy faces a growing demand of tools able to map radiation quality within the irradiated volume. Although analytical computations and simulations provide useful estimations of dose and radiation quality, the direct measure of those parameters would improve ion-beam therapy in particular when deep-seated tumours are irradiated, tissue composition and density are variable or organs at risk are near the tumour. Several ion-beam therapy facilities are studying detectors and procedures for measuring the radiation quality on a microdosimetric as well as a nanodosimetric scale. Simplicity and miniaturisation of the devices are essential for measurements first in phantoms and thereafter during therapy, particularly for intra-cavity detectors. MedAustron is studying solid-state detectors based on a single crystal chemical vapour deposition diamond. In collaboration with Italian National Institute for Nuclear Physics (INFN), Tor Vergata and Legnaro; INFN-microdosimetry and track structure project; Austrian Institute of Technology, Vienna; and Italian National agency for new technologies, energy and sustainable economic development, Rome, prototypes have been developed to characterise radiation quality in sizes equivalent to one micrometre of biological tissue. (authors)

  3. Promotion of high-quality treatment and uninterrupted service of radiation therapy linear accelerators

    International Nuclear Information System (INIS)

    The experience of operation of radiotherapy complex at Donetsk Antitumor Center showed that a number of calibration and dosimetry tests were an inevitable part of high-quality radiation treatment and timely prevention of inconsiderable disorders in the work of linear accelerators, therefore the engineering service of this equipment should consist of various specialists.

  4. Quality assurance in military medical research and medical radiation accident management.

    Science.gov (United States)

    Hotz, Mark E; Meineke, Viktor

    2012-08-01

    The provision of quality radiation-related medical diagnostic and therapeutic treatments cannot occur without the presence of robust quality assurance and standardization programs. Medical laboratory services are essential in patient treatment and must be able to meet the needs of all patients and the clinical personnel responsible for the medical care of these patients. Clinical personnel involved in patient care must embody the quality assurance process in daily work to ensure program sustainability. In conformance with the German Federal Government's concept for modern departmental research, the international standard ISO 9001, one of the relevant standards of the International Organization for Standardization (ISO), is applied in quality assurance in military medical research. By its holistic approach, this internationally accepted standard provides an excellent basis for establishing a modern quality management system in line with international standards. Furthermore, this standard can serve as a sound basis for the further development of an already established quality management system when additional standards shall apply, as for instance in reference laboratories or medical laboratories. Besides quality assurance, a military medical facility must manage additional risk events in the context of early recognition/detection of health risks of military personnel on deployment in order to be able to take appropriate preventive and protective measures; for instance, with medical radiation accident management. The international standard ISO 31000:2009 can serve as a guideline for establishing risk management. Clear organizational structures and defined work processes are required when individual laboratory units seek accreditation according to specific laboratory standards. Furthermore, international efforts to develop health laboratory standards must be reinforced that support sustainable quality assurance, as in the exchange and comparison of test results within

  5. Solar radiation trend across China in recent decades: a revisit with quality-controlled data

    Directory of Open Access Journals (Sweden)

    W.-J. Tang

    2011-01-01

    Full Text Available Solar radiation is one of the most important factors affecting climate and environment, and its long-term variation is of much concern in climate change studies. In the light of the limited number of radiation stations with reliable long-term time series observations, this paper presents a new evaluation of the long-term variation of surface solar radiation over China by combining quality-controlled observed data and two radiation models. One is the ANN-based (Artificial Neutral Network model and the other is a physical model. The two models produce radiation trends comparable to the observed ones at a few validation stations possessing reliable and continuous data. Then, the trend estimate is extended by the ANN-based model to all 96 radiation stations and furthermore extended by the physical model to all 716 China Meteorological Administration (CMA routine stations. The new trend estimate is different from previous ones in two aspects. First, the magnitude of solar radiation over China decreased by about −0.23 W m−2 yr−1 between 1961 and 2000, which is greatly less in magnitude than trend slopes estimated in previous studies (ranging over −0.41 ~ −0.52 W m−2 yr−1. Second, the "From Dimming to Brightening" transition in China during the late 1980s ~ the early 1990s was addressed in previous studies, but this study indicates the solar radiation reached a stable level since the 1990s and the transition is not noticeable. These differences indicate the importance of data-quality control and analysis approaches. Finally, an obvious transition from brightening to dimming around 1978 is found over the Tibetan Plateau, where aerosol loads are very low, indicating that the importance of cloud changes in altering solar radiation may be comparable to that of the aerosol changes.

  6. Quality assurance of the dose delivered by small radiation segments

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Vebeke N.; Evans, Philip M. [Joint Department of Physics, Royal Marsden NHS Trust and Institute of Cancer Research Downs Road, Sutton, Surrey SM2 5PT (United Kingdom); Budgell, Geoffrey J.; Mott, Judith H.L.; Williams, Peter C. [North Western Medical Physics, Christie Hospital NHS Trust, Withington, Manchester M20 4BX (United Kingdom); Brugmans, Marco J.P.; Wittkaemper, Frits W.; Mijnheer, Ben J. [Radiotherapy Department, The Netherlands Cancer Institute/Antoni van Leeuwenhoek Huis, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands); Brown, Kevin [Elekta Oncology System Ldt., Linac House, Fleming Way, Crawley, West Sussex RH10 2RR (United Kingdom)

    1998-09-01

    The use of intensity modulation with multiple static fields has been suggested by many authors as a way to achieve highly conformal fields in radiotherapy. However, quality assurance of linear accelerators is generally done only for beam segments of 100 MU or higher, and by measuring beam profiles once the beam has stabilized. We propose a set of measurements to check the stability of dose delivery in small segments, and present measured data from three radiotherapy centres. The dose delivered per monitor unit, MU, was measured for various numbers of MU segments. The field flatness and symmetry were measured using either photographic films that are subsequently scanned by a densitometer, or by using a diode array. We performed the set of measurements at the three radiotherapy centres on a set of five different Philips SL accelerators with energies of 6 MV, 8 MV, 10 MV and 18 MV. The dose per monitor unit over the range of 1 to 100 MU was found to be accurate to within {+-}5% of the nominal dose per monitor unit as defined for the delivery of 100 MU for all the energies. For four out of the five accelerators the dose per monitor unit over the same range was even found to be accurate to within {+-}2%. The flatness and symmetry were in some cases found to be larger for small segments by a maximum of 9% of the flatness/symmetry for large segments. The result of this study provides the dosimetric evidence that the delivery of small segment doses as top-up fields for beam intensity modulation is feasible. However, it should be stressed that linear accelerators have different characteristics for the delivery of small segments, hence this type of measurement should be performed for each machine before the delivery of small dose segments is approved. In some cases it may be advisable to use a low pulse repetition frequency (PRF) to obtain more accurate dose delivery of small segments. (author)

  7. Quality assurance of the dose delivered by small radiation segments

    International Nuclear Information System (INIS)

    The use of intensity modulation with multiple static fields has been suggested by many authors as a way to achieve highly conformal fields in radiotherapy. However, quality assurance of linear accelerators is generally done only for beam segments of 100 MU or higher, and by measuring beam profiles once the beam has stabilized. We propose a set of measurements to check the stability of dose delivery in small segments, and present measured data from three radiotherapy centres. The dose delivered per monitor unit, MU, was measured for various numbers of MU segments. The field flatness and symmetry were measured using either photographic films that are subsequently scanned by a densitometer, or by using a diode array. We performed the set of measurements at the three radiotherapy centres on a set of five different Philips SL accelerators with energies of 6 MV, 8 MV, 10 MV and 18 MV. The dose per monitor unit over the range of 1 to 100 MU was found to be accurate to within ±5% of the nominal dose per monitor unit as defined for the delivery of 100 MU for all the energies. For four out of the five accelerators the dose per monitor unit over the same range was even found to be accurate to within ±2%. The flatness and symmetry were in some cases found to be larger for small segments by a maximum of 9% of the flatness/symmetry for large segments. The result of this study provides the dosimetric evidence that the delivery of small segment doses as top-up fields for beam intensity modulation is feasible. However, it should be stressed that linear accelerators have different characteristics for the delivery of small segments, hence this type of measurement should be performed for each machine before the delivery of small dose segments is approved. In some cases it may be advisable to use a low pulse repetition frequency (PRF) to obtain more accurate dose delivery of small segments. (author)

  8. Characterization of UV radiation sensitive frog cell lines

    International Nuclear Information System (INIS)

    Twenty-one subclones of nine frog cell isolates were tested for sensitivity to a panel of DNA damaging agents. Two clones were identified which had a greater than wild type level of sensitivity to UV radiation but had a wild type level of sensitivity to the other agents. These clones were the haploid RRP602-7 and the diploid RRP802-1. RRP802-1 was found to be unstable with respect to UV sensitivity. The line was cloned in order to isolate stable sensitive and wild type derivatives. RRP802-1-16, a UV sensitive clone and RRP802-1-13, a clone with a wild type level of sensitivity to UV radiation, were isolated. The UV radiation sensitivity of RRP602-7, RRP802-1 and RRP802-1-16 did not correlate with cell size, cell shape, cell cycle distribution or ploidy. The cell cycle distribution after UV irradiation, the rate of DNA synthesis after UV-irradiation, the DNA polymerase α activity and the sister chromatid exchange frequency were all measured in RRP602-7, RRP802-1 and RRP802-1-16 in order to examine the DNA repair capacity. The presence of DNA repair pathways was examined directly in RRP602-7, RRP802-1 and RRP802-1-16. All were found to be proficient in photo-reactivation repair and postreplication repair of UV elicited DNA damage

  9. Photoluminescence in large fluence radiation irradiated space silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Hisamatsu, Tadashi; Kawasaki, Osamu; Matsuda, Sumio [National Space Development Agency of Japan, Tsukuba, Ibaraki (Japan). Tsukuba Space Center; Tsukamoto, Kazuyoshi

    1997-03-01

    Photoluminescence spectroscopy measurements were carried out for silicon 50{mu}m BSFR space solar cells irradiated with 1MeV electrons with a fluence exceeding 1 x 10{sup 16} e/cm{sup 2} and 10MeV protons with a fluence exceeding 1 x 10{sup 13} p/cm{sup 2}. The results were compared with the previous result performed in a relative low fluence region, and the radiation-induced defects which cause anomalous degradation of the cell performance in such large fluence regions were discussed. As far as we know, this is the first report which presents the PL measurement results at 4.2K of the large fluence radiation irradiated silicon solar cells. (author)

  10. Radiation damage and annealing of amorphous silicon solar cells

    Science.gov (United States)

    Byvik, C. E.; Slemp, W. S.; Smith, B. T.; Buoncristiani, A. M.

    1984-01-01

    Amorphous silicon solar cells were irradiated with 1 MeV electrons at the Space Environmental Effects Laboratory of the NASA Langley Research Center. The cells accumulated a total fluence of 10 to the 14th, 10 to the 15th, and 10 to the 16th electrons per square centimeter and exhibited increasing degradation with each irradiation. This degradation was tracked by evaluating the I-V curves for AM0 illumination and the relative spectral response. The observed radiation damage was reversed following an anneal of the cells under vacuum at 200 C for 2 hours.

  11. Determination of quality factor in mixed radiation fields using a recombination chamber

    International Nuclear Information System (INIS)

    A recombination chamber was used for determination of the recombination index of radiation quality (Q4). The possibility of calculation of the quality factor defined by ICRP Report 60 from the measured Q4 values is discussed. The calculations were performed for the experimental results, obtained in radiation fields of fast neutrons (from 0.9 MeV up to 14 MeV), high energy (350 MeV) neutrons, high energy (200 MeV) protons and for alpha particles. It was found that the calculation procedure can be used for most existing mixed radiation fields with accuracy of about 25%, if the photon component of the absorbed dose is independently determined. (author)

  12. Effect of enhanced UV-B radiation on yield and quality of rice

    International Nuclear Information System (INIS)

    The effects of enhanced UV-B radiation on yield and quality of two rice cuhivars(ShenNong 6014 and ShenNong 265) are studied in potted method. There were three treatments including natural light (TCK), enhanced 5% UV-B radiation (T) and enhanced 10% (T). The results showed that enhanced UV-B radiation decreases yield components, the percentage of brown rice (0.66%-7.06%), head rice rate (5.65%-18.88%), the rate of white rice (22.17%-40.16%), grain area (2.61%-6.25%), fatty acid contents (1.23%-54.19%) and eating quality (1.07%-16.78%) but increasea protein content (4.65%-10.71%) and amylose content of rice (0.56%-4.81%). The effects of T2 was stronger than T1

  13. Radiation induced cell death in cervical squamous cell carcinoma. An immunohistochemical and ultrastructural study

    International Nuclear Information System (INIS)

    To study the process of cell death in cervical squamous cell carcinoma (SCC) after radiation, an ultrastructural and immunohistochemical study was performed. Paraffin-embedded tissue blocks of biopsy samples pre- and post-radiation stage III SCC (n=15) were collected. Irradiation caused varying ultrastructural changes including nuclear and cytoplasmic disorganization suggesting cell necrosis. Immunohistochemically, the pre-radiation specimens showed no positive reaction for tumor necrosis factor-alpha (TNF-α), tumor necrosis factor-receptor (TNF-γ) or Fas. C-fos, p53 and bcl-2 showed positive reactions in only a few non-irradiated specimens. All of the irradiated specimens showed a positive reaction for TNF-α, and variable positive reactions were observed for TNF-γ, Fas, p53, c-fos and bcl-2. These results suggest that TNF-α, TNF-γ, and c-fos are responsible for radiation induced cell death in cervical SCC. (author)

  14. Cell phone radiation effects on cytogenetic abnormalities of oral mucosal cells

    Directory of Open Access Journals (Sweden)

    Natália Batista DAROIT

    2015-01-01

    Full Text Available The aim of this study was to evaluate the effects of exposure to cell phone electromagnetic radiation on the frequency of micronuclei, broken eggs cells, binucleated cells, and karyorrhexis in epithelial cells of the oral mucosa. The sample was composed of 60 cell phone users, who were non-smokers and non-drinkers, and had no clinically visible oral lesions. Cells were obtained from anatomical sites with the highest incidence of oral cancer: lower lip, border of the tongue, and floor of the mouth. The Feulgen reaction was used for quantification of nuclear anomalies in 1,000 cells/slide. A slightly increase in the number of micronucleated cells in the lower lip and in binucleated cells on the floor of the mouth was observed in individuals who used their phones > 60 minutes/week. The analysis also revealed an increased number of broken eggs in the tongue of individuals owning a cell phone for over eight years. Results suggest that exposure to electromagnetic waves emitted by cell phones can increase nuclear abnormalities in individuals who use a cell phone for more than 60 minutes per week and for over eight years. Based on the present findings, we suggest that exposure to electromagnetic radiation emitted by cell phones may interfere with the development of metanuclear anomalies. Therefore, it is demonstrated that, despite a significant increase in these anomalies, the radiation emitted by cell phones among frequent users is within acceptable physiological limits.

  15. The role of constitutive and inducible processes in the response of human squamous cell carcinoma cell lines to ionizing radiation

    International Nuclear Information System (INIS)

    The inherent radiation sensitivity of the cells within a tumor is thought to contribute to the success or failure of radiation therapy. In vitro studies have shown that differences in the radiation sensitivity of squamous cell carcinoma cell lines reflect alterations in DNA repair. These alterations result from constitutive changes in chromosome organization, not radiation-inducible processes. While inducible responses may play some role in the radiation response of tumor cells, there is no evidence for their involvement in inherent differences in tumor cell radiosensitivity or in the success or failure of radiotherapy of squamous cell carcinomas. 21 refs., 1 fig., 1 tab

  16. Towards microbiological quality assurance in radiation sterilization processing: simulation of the radiation inactivation process

    Energy Technology Data Exchange (ETDEWEB)

    Fitch, F.R.; Dwyer, J. (Manchester Univ. (UK). Inst. of Science and Technology); Doolan, P.T. (Becton Dickinson and Co., Parasmus, NJ (USA)); Dwyer, V.M. (York Univ. (UK). Dept. of Physics); Halls, N.A. (Becton Dickinson and Co., Dun Laoghaire (Ireland)); Tallentire, A. (Manchester Univ. (UK). Dept. of Pharmacy)

    1985-03-01

    A method is developed for computer simulation of the inactivation of microorganisms on items by irradiation. It is shown that in a population of items subjected to increasing doses of radiation the proportion contaminated approaches the appropriate Limiting Case, outlined in a previous paper, as numbers of organisms are decreased by inactivation. The behaviour of populations of items having different proportions of 'spikes' (high bioburden levels) is considered.

  17. Towards microbiological quality assurance in radiation sterilization processing: simulation of the radiation inactivation process

    International Nuclear Information System (INIS)

    A method is developed for computer simulation of the inactivation of microorganisms on items by irradiation. It is shown that in a population of items subjected to increasing doses of radiation the proportion contaminated approaches the appropriate Limiting Case, outlined in a previous paper, as numbers of organisms are decreased by inactivation. The behaviour of populations of items having different proportions of 'spikes' (high bioburden levels) is considered. (author)

  18. Classical radiation reaction in particle-in-cell simulations

    Science.gov (United States)

    Vranic, M.; Martins, J. L.; Fonseca, R. A.; Silva, L. O.

    2016-07-01

    Under the presence of ultra high intensity lasers or other intense electromagnetic fields the motion of particles in the ultrarelativistic regime can be severely affected by radiation reaction. The standard particle-in-cell (PIC) algorithms do not include radiation reaction effects. Even though this is a well known mechanism, there is not yet a definite algorithm nor a standard technique to include radiation reaction in PIC codes. We have compared several models for the calculation of the radiation reaction force, with the goal of implementing an algorithm for classical radiation reaction in the Osiris framework, a state-of-the-art PIC code. The results of the different models are compared with standard analytical results, and the relevance/advantages of each model are discussed. Numerical issues relevant to PIC codes such as resolution requirements, application of radiation reaction to macro particles and computational cost are also addressed. For parameters of interest where the classical description of the electron motion is applicable, all the models considered are shown to give comparable results. The Landau and Lifshitz reduced model is chosen for implementation as one of the candidates with the minimal overhead and no additional memory requirements.

  19. Proposal of guidelines for quality assurance in radiation oncology in Slovakia

    International Nuclear Information System (INIS)

    According to the requirements of the Directive 97/43 EURATOM and the Slovak Government decree No. 340/2006 a quality assurance (QA) system have to be implemented into the practices of radiation oncology departments, harmonized with the international recommendations. For fulfilling this task was in the framework of the activities of the Slovak Health Ministry Commission for QA in radiology , created a group of specialists for preparation of Guidelines for various modalities of radiotherapy equipment and for treatment planning systems, including the standard working methods for quality control of technical and operational characteristics , as well as verification of the functional parameters in the treatment process. The proposed Guidelines are divided into the six specific parts, with following items: Medical electron accelerators; Therapy simulators; Superficial therapy with X-rays; Gamma extemal beam therapy; Remote afterloading brachytherapy; and Treatment planning systems. The main objectives of the guidelines are to formulate formally established quality controls during: Acceptance testing after installation; Commissioning by the necessary periodic quality controls; and Repairs or maintenance work that might alter the radiation situation. The presentation will describe the specific periodic quality controls, technical and functional characteristics of each equipment and of the treatment planning, as well as the tolerances, which prevent the undesirable impact on the radiation output and compliance with all relevant specified requirements. (authors)

  20. Radiation response characteristics of human cell in vitro

    International Nuclear Information System (INIS)

    Improvements in tissue culture techniques and growth media have made it possible to culture a range of cells of human origin, both normal and malignant. The most recent addition to the list are endothelial cells. Interesting results have been obtained, some of which may have implications in Radiation Therapy. (i) Repair of Potentially Lethal Damage (PLDR) has been observed in all cell lines investigated; cells of normal origin repair PLD at least as well as malignant cells, which makes clinical trials of PLDR inhibitors of doubtful usefulness. (ii) PLD in fibroblasts of human origin appears to have a component that is repaired rapidly, in a matter of minutes, as well as a slower component that takes hours to repair. (iii) Sublethal damage repair, manifest by a dose-rate effect, has also been observed in all human cell lines tested. Cells of normal tissue origin, including fibroblasts and endothelial cells, exhibit a dose-rate effect that is intermediate between that for cells from traditionally resistant tumors (melanoma and osteosarcoma) and cells from more sensitive tumors (neuroblastoma and breast). (iv) Fibroblasts from patients with Ataxia Telangectasia (AT) are much more sensitive to x-rays, with a D/sub o/ about half that for normal human fibroblasts. Nevertheless repair of both PLD and SLD can be demonstrated in these cells

  1. The relationship between compression force, image quality and radiation dose in mammography

    Directory of Open Access Journals (Sweden)

    A Korf

    2009-11-01

    Full Text Available Background. Mammography aims to obtain mammograms of best possible image quality with least possible radiation dose.1 Theoretically, an increase in breast compression gives a reduction in thickness, without changing the density, resulting in improved image quality and reduced radiation dose. Aim.\tThis study aims to investigate the relationship between compression force, phantom thickness, image quality and radiation dose. The existence of a compression point beyond which increased compression gives a change in density rather than thickness is also considered. Method. Image quality is assessed with a contrast-detail phantom within Superflab phantom on a computed radiography (CR mammography unit using automatic exposure control (AEC. Image quality is determined by visual inspection and image quality figure (IQF scoring. The effect of compression and lesion depth on image quality is determined. Entrance and exit doses are calculated. The relationship between entrance dose, compression and thickness is investigated, as is the existence of a compression point beyond which a change in phantom density occurs. The average glandular dose (AGD is calculated from the scanning average level (SAL and logarithmic mean (LgM according to Koen et al,2 and compared to the allowable limit. Results.\tThe geometry effect was not observed. An improvement in image quality with increased compression was found. Entrance dose did decrease with increased compression. This trend was not observed with exit dose as AEC was used and exit dose was calculated from SAL values. The “change-in-density” point of compression was determined. Both LgM and SAL could be used successfully for AGD calculation.

  2. The action of ultraviolet radiation on the cell proliferation of two-cell mouse embryos

    International Nuclear Information System (INIS)

    The two-cell mouse embryo has a unique cell cycle of a short DNA synthesis (S) phase and an extremely long post-DNA synthesis (G2) phase. An attempt was made to investigate the radiation biology of the long G2 phase using UV radiation as a probe. Two cell mouse embryos, at various positions in the cell cycle, were UV-irradiated in phosphate-buffered saline. The embryos were cultured for a few hours to 3 days to assay for their cell proliferative characteristics. The embryos were most sensitive to the killing action of UV radiation in the late G2 phase. The embryos divided more than two times after low UV fluences before dying and experienced G2 phase delays. These results can be contrasted to the situation in somatic cells, in which the action of UV radiation is S phase selective. One possibility is that the target for the action of UV radiation is different in two-cell mouse embryos from that in somatic cells and that the target is similar to that for X-ray effects. (author)

  3. QUALITY OF RADIOGRAPHIC IMAGES: LABORATORY EVALUATION OF INTRAORAL FILMS, FILTERS, COLLIMATORS, AND RADIATION EXPOSURE

    Directory of Open Access Journals (Sweden)

    TAMBURUS José Roberto

    1997-01-01

    Full Text Available In order to evaluate density, radiographic contrast and dose of radiation exposure, the author analyzed 80 radiographs containing 640 optical density data of the images of a penetrometer, exposed to the radiation beam with combinations between D and E periapical films, aluminum and copper/aluminum filters, and circular or rectangular collimators. The data obtained were analyzed by ANOVA and allowed the following conclusions: 1 aluminum filtration resulted in improved image contrast; 2 the use of group D film and an aluminum filter produced improved image contrast quality; 3 the rectangular collimator contributed to the production of improved contrast and to the reduction of radiation exposure, but did not affect density; 4 the combination of copper/aluminum filter, E group film and rectangular collimation significantly reduced radiation exposure.

  4. Studies on the control mechanism and the degenerative immune function of dendritic cells using radiation

    Energy Technology Data Exchange (ETDEWEB)

    Yee, Sung Tae; Kim, Jong Jin; Choi, Ji Na; Park, Jung Eun; Jeong, Young Ran [Sunchon National University, Sunchon (Korea, Republic of)

    2010-05-15

    Dendritic cells are actively used as cellular adjuvant in cancer immunotherapy. However, although DC immunotherapies primarily target the elderly population, little is known about the effect of aging on DC functions. Here, we compared the T-cell stimulation, cytokine production, and costimulatory molecule expression of spleen or bone marrow-derived CD11c{sup +} DCs of C57BL/6 mice. In the first year, we compared various function of dendritic cells isolated from young and gamma-irradiated 57BL/6 mice(5 weeks after {gamma}-radiation) for the development of aging models using radiation. In the second year, we also compared the function of spleen- and bone marrow-derived dendritic cells of young(2-3 months) and old(23-24 months) 57BL/6 mice. And we studied the differences of spleen- and bone marrow-derived dendritic cells of young and gamma-irradiated 57BL/6 mice(2, 4, 6 months after {gamma}-radiation) for the development of aging models in third year. And we obtained various differences between spleen- and bone marrow-derived dendritic cells of normal and old(23-24 months) or {gamma}-irradiated 57BL/6 mice. It is possible to use our results as age-associated model for modulation of the declined immunity and hematopoiesis for treatment of cancer, adult diseases and stress in aging. Such studies on the mechanism of aging model would further lead to new avenues for the development of functional foods which effect such as pathogenesis, inflammatory and autoimmune disorders. It will contributed to activation of related industry conforming quality and diversity of radiation industry. The techniques developed in our research may provide novel therapeutic modalities for age-associated immune dysfunctions

  5. Radiation-responsive transcriptome analysis in human lymphoid cells

    International Nuclear Information System (INIS)

    Ionising radiation (IR) causes DNA (deoxyribonucleic acid) injury and activates intracellular signal pathways including the regulation of DNA repair and cell cycle. However, the further knowledge of molecular events involved in radiation exposure is essential to more comprehensively understand the effects of irradiation. Therefore, the gene expressions of mRNA (messenger ribonucleic acid) by X-ray irradiation in human B lymphoblasts cell line (IM-9) using a microarray were investigated. The mRNA expressions of 65 genes were shown to be up-regulated at >2.0-fold in irradiated cells (4 Gy) when compared with non-irradiated cells (0 Gy) by microarray analysis. Among 65 genes, a large number of genes were up-regulated with an X-ray dose-dependent change. These results indicate that the up-regulation of their mRNAs is the effects of irradiation and may be due to biological dosimetric markers for the evaluation of radiation exposure in the future. (authors)

  6. Regulatory mechanism of radiation-induced cancer cell death by the change of cell cycle

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Soo Jin; Jeong, Min Ho; Jang, Ji Yeon [College of Medicine, Donga Univ., Pusan (Korea, Republic of)

    2003-09-01

    In our previous study, we have shown the main cell death pattern induced by irradiation or protein tyrosine kinase (PTK) inhibitors in K562 human myelogenous leukemic cell line. Death of the cells treated with irradiation alone was characterized by mitotic catastrophe and typical radiation-induced apoptosis was accelerated by herbimycin A (HMA). Both types of cell death were inhibited by genistein. In this study, we investigated the effects of HMA and genistein on cell cycle regulation and its correlation with the alterations of radiation-induced cell death. K562 cells in exponential growth phase were used for this study. The cells were irradiated with 10 Gy using 6 MeV Linac (200-300 cGy/min). Immediately after irradiation, cells were treated with 250 nM of HMA or 25{mu}M of genistein. The distributions of cell cycle, the expressions of cell cycle-related protein, the activities of cyclin-dependent kinase, and the yield of senescence and differentiation were analyzed. X-irradiated cells were arrested in the G2 phase of the cell cycle but unlike the p53-positive cells, they were not able to sustain the cell cycle arrest. An accumulation of cells in G2 phase of first cell-cycle post-treatment and an increase of cyclin B1 were correlated with spontaneous, premature, chromosome condensation and mitotic catastrophe. HMA induced rapid G2 checkpoint abrogation and concomitant p53-independent G1 accumulation HMA-induced cell cycle modifications correlated with the increase of cdc2 kinase activity, the decrease of the expressions of cyclins E and A and of CDK2 kinase activity, and the enhancement of radiation-induced apoptosis. Genistein maintained cells that were arrested in the G2-phase, decreased the expressions of cyclin B1 and cdc25C and cdc2 kinase activity, increased the expression of p16, and sustained senescence and megakaryocytic differentiation. The effects of HMA and genistein on the radiation-induced cell death of K562 cells were closely related to the cell

  7. Autologous adipose-derived regenerative cells are effective for chronic intractable radiation injuries

    International Nuclear Information System (INIS)

    Effective therapy for chronic radiation injuries, such as ulcers, is prone to infection. Stiffness is expected since the therapeutic radiation often involves wider and deeper tissues and often requires extensive debridement and reconstruction, which are not sometimes appropriate for elderly and compromised hosts. Autologous adipose-derived regenerative cells (ADRCs) are highly yielding, forming relatively elderly aged consecutive 10 cases, 63.6±14.9 y (52-89 y), with mean radiation dose of 75.0±35.4 Gy (50-120 Gy) were included with at least 10-month follow-up. Minimal debridement and ADRC injection in the wound bed and margin along with the injection of mixture of fat and ADRCs in the periphery were tested for efficacy and regenerated tissue quality by clinically as well as imaging by computed tomography and magnetic resonance imaging. Uncultured ADRCs of 1.6±1.3 x 107 cells were obtained. All cases healed uneventfully after 6.6±3.2 weeks (2-10 weeks) post-operatively. The done site morbidity was negligible and without major complications, such as paralysis or massive haematoma. The regenerated tissue quality was significantly superior to the pre-operative one and the mixture of fat and ADRCs connected to the intact tissue was very soft and pliable. Mean follow-up at 1.9±0.8 y (0.9-2.9 y) revealed no recurrence or new ulceration after treatment. Thus, the ADRCs treatment for decades-long radiation injuries is effective, safe and improves the quality of wounds. (authors)

  8. DNA methylation changes in cells regrowing after fractioned ionizing radiation

    International Nuclear Information System (INIS)

    Background and purpose: Repeated exposure to ionizing radiation (IR) can result in adaptive reactions. While DNA methylation changes in adaption to repeated stress exposure are established for a variety of drugs, their role in fractioned ionizing radiation is largely unknown. Material and methods: MCF7 breast cancer cells were treated 5 times a week with IR in fractions of 2 Gy, resulting in total doses of 10 and 20 Gy. Cells were harvested 48 and 72 h after the last irradiation, as well as after a recovery period of at least 14 d. To identify genes differentially methylated in irradiated versus non-irradiated cells, we used methyl-CpG immunoprecipitation (MCIp) followed by global methylation profiling on CpG island microarrays. Results: MCIp profiling revealed methylation changes in several CpG islands 48 h after FIR with 10 and 20 Gy. Cells receiving a total dose of 10 Gy started regrowing after 14 d and exhibited similar radioresistance as mock-treated cells. Differential methylation of the CpG units associated with FOXC1 (p < 0.001) and TRAPPC9 (p < 0.001) could be confirmed by time-of-flight mass spectrometry (Sequenom). Conclusions: In summary, these data indicate that regrowth of MCF7 cells after 10 Gy FIR is associated with locus-specific alterations in DNA methylation.

  9. Comparison of gamma radiation - induced effects in two human prostate cancer cells

    International Nuclear Information System (INIS)

    In this study, the effects of gamma radiation on two hormone refractory human prostate cancer cell lines, DU 145 and PC-3, were followed. It was shown that gamma radiation induced significant inhibition of cell proliferation and viability in dose dependent manner. Antiproliferative effects of radiation were similar in both cell lines, and more pronounced than cytotoxic effects. In addition to that, PC-3 cell line was more resistant to radiation -induced cytotoxicity. (author)

  10. Influence of different exposure modes on image quality and radiation dose in digital mammography

    International Nuclear Information System (INIS)

    Objective: To evaluate the effect of different exposure modes on radiation dose and image quality in digital mammography, and to explore how to reduce patient's radiation injury by choosing proper exposure mode and exposure conditions without sacrifice image quality. Methods: A breast phantom was exposed by using automatic exposure mode (60 mAs, 28 k/V) and manual exposure modes (37.5 to 70 mAs range, 24 to 32 kV range) respectively. Same oppression thickness and pressure were set for all modes. The average glandular dose (AGD), entrance surface dose (ESD), and image quality score according to American College of Radiology (ACR) criteria were recorded for each image. Kruskal Wallis test was used to compare the image quality scores between automatic and manual modes. All statistic analyses were performed by using SPSS17.0. Results: Compared to automatic exposure mode (60 mAs, 28 k/V), the overall score of image quality of manual modes (45 to 70 mAs range, 26 to 32 kV range) had no significant difference. Both ESD and ACD decreased 26.1% and increased 15.4% when the tube loading was changed from 60 mAs to 45 mAs and 70 mAs respectively. The ESD and ACD decreased 22.6%, 28.2% and increased 47.0%, 62.7% when the tube voltage was changed from 28 kV to 26 kV and 32 kV respectively. Conclusion: When the image quality reaches to a certain level, it will not be raised by a higher photographic condition. Without sacrifice image quality, the tube loading and tube voltage can be manually decreased to reduce radiation dose. (authors)

  11. Radiation safety requirements for radioactive waste management in the framework of a quality management system

    International Nuclear Information System (INIS)

    The Center for Radiation Protection and Hygiene (CPHR) is the institution responsible for the management of radioactive wastes generated from nuclear applications in medicine, industry and research in Cuba. Radioactive Waste Management Service is provided at a national level and it includes the collection and transportation of radioactive wastes to the Centralized Waste Management Facilities, where they are characterized, segregated, treated, conditioned and stored. A Quality Management System, according to the ISO 9001 Standard has been implemented for the RWM Service at CPHR. The Management System includes the radiation safety requirements established for RWM in national regulations and in the Licence's conditions. The role of the Regulatory Body and the Radiation Protection Officer in the Quality Management System, the authorization of practices, training and personal qualification, record keeping, inspections of the Regulatory Body and internal inspection of the Radiation Protection Officer, among other aspects, are described in this paper. The Quality Management System has shown to be an efficient tool to demonstrate that adequate measures are in place to ensure the safety in radioactive waste management activities and their continual improvement. (authors)

  12. Discrimination of radiation quality through second harmonic out-of-phase cw-ESR detection.

    Science.gov (United States)

    Marrale, Maurizio; Longo, Anna; Brai, Maria; Barbon, Antonio; Brustolon, Marina

    2014-02-01

    The ability to discriminate the quality of ionizing radiation is important because the biological effects produced in tissue strongly depends on both absorbed dose and linear energy transfer (LET) of ionizing particles. Here we present an experimental electron spin resonance (ESR) analysis aimed at discriminating the effective LETs of various radiation beams (e.g., 19.3 MeV protons, (60)Co photons and thermal neutrons). The measurement of the intensities of the continuous wave spectrometer signal channel first harmonic in-phase and the second harmonic out-of-phase components are used to distinguish the radiation quality. A computational analysis, was carried out to evaluate the dependence of the first harmonic in-phase and second harmonic out-of-phase components on microwave power, modulation amplitude and relaxation times, and highlights that these components could be used to point out differences in the relaxation times. On the basis of this numerical analysis the experimental results are discussed. The methodology described in this study has the potential to provide information on radiation quality. PMID:24524346

  13. Radiation- and chemoinduced multidrug resistance in colon carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Bartkowiak, Detlef; Stempfhuber, Michael; Wiegel, Thomas; Bottke, Dirk [Dept. of Radiotherapy and Radiooncology, Univ. of Ulm (Germany)

    2009-12-15

    Background and purpose: radiation can induce multidrug resistance (MDR) and thus interfere with simultaneous or subsequent chemotherapy. In SW620 colon carcinoma cells, the interrelation of various biological endpoints of MDR was analyzed and the potential of fractionated irradiation and chemoselection to evoke MDR was compared. Material and methods: to induce/select an MDR phenotype, SW620 were exposed to either 27 Gy in 1.8-Gy daily fractions or to 50% inhibiting concentrations of doxorubicin or cisplatin, given over 6-15 weeks. Expression of genes involved in MDR, including glutathione metabolism, was determined by semiquantitative RT-PCR (reverse transcription-polymerase chain reaction). Efflux was analyzed by flow cytometry after staining with rhodamine-123 or 5-chloromethyl fluorescein diacetate. Apoptosis was monitored after pulse exposure to doxorubicin or cisplatin. Colony-forming assays were performed under continuous drug exposure. Results: a pronounced gene induction was found in MRP2 after cisplatin selection and up to 3 weeks after radiation. LRP was activated only shortly after radiation. Radiation enhanced rhodamine-123 efflux to a similar extent as short-term chemoselection but not as much as long-term drug exposure. Drug-induced apoptosis was slightly delayed in preirradiated cells. Clonogenic growth in the progeny of irradiated cells was less sensitive to cisplatin but not to doxorubicin. Conclusion: fractionated radiation can induce an MDR phenotype in SW620. However, long-term drug exposure establishes a more efficient selection. Various endpoints are not fully concordant regarding the extent of MDR. Posttranscriptional modifications, pleiotropic regulation, and alternative pathways may cause these discrepancies. (orig.)

  14. Stem cell, cytokine and plastic surgical management for radiation injuries

    International Nuclear Information System (INIS)

    Increasing concern on systemic and local radiation injuries caused by nuclear power plant accident, therapeutic irradiation or nuclear terrorism should be treated and prevented properly for life-saving and improved wound management. We therefore reviewed our therapeutic regimens and for local radiation injuries and propose surgical methods reflecting the importance of the systemic and general conditions. For local radiation injuries, after careful and complete debridement, sequential surgeries with local flap, arterialized or perforator flap and to free flap are used when the patients' general conditions allow. Occasionally, undetermined wound margins in acute emergency radiation injuries and the regenerative surgical modalities should be attempted with temporal artificial dermis impregnated and sprayed with angiogenic factor such as basic fibroblast growth factor (bFGF) and secondary reconstruction can be a candidate for demarcation and saving the donor morbidity. Human mesenchymal stem cells (hMSCs) and adipose-derived stem cells (ADSCs), together with angiogenic and mitogenic factor of basic fibroblast growth factor (bFGF) and an artificial dermis were applied over the excised irradiated skin defect are tested for differentiation and local stimulation effects in the radiation-exposed wounds. The perforator flap and artificial dermal template with growth factor were successful for reconstruction in patients who are suffering from complex underlying disease. Patients were uneventfully treated with minimal morbidities. The hMSCs are strongly proliferative even after 20 Gy irradiation in vitro. Immediate artificial dermis application impregnated with hMSCs and bFGF over the 20 Gy irradiated skin and soft tissues demonstrated the significantly improved fat angio genesis, architected dermal reconstitution and less inflammatory epidermal recovery. Even though emergent cases are more often experienced, detailed understanding of underlying diseases and rational

  15. EORTC radiation proctitis-specific quality of life module - Pretesting in four European countries

    International Nuclear Information System (INIS)

    Background and purpose: Radiation proctitis is a side effect which can occur after pelvic radiation therapy. Currently available questionnaires do not comprehensively assess the range of problems, nor impact on quality of life associated with proctitis. This article reports on the cultural testing phase of an EORTC module (QLQ-PRT21) developed to assess radiation proctitis specific issues and designed to be used in conjunction with the EORTC core quality of life questionnaire (QLQ-C30). Methods: The previously developed 21-item module, pre-tested in Australia, was translated into Norwegian, German, French and Italian. Patients completed the EORTC QLQ-C30 and module questionnaires towards the end of their radical pelvic radiation treatment to target acute side effects. Patients experiencing chronic proctitis were also surveyed. Patients also participated in structured interviews to determine issues of comprehensibility, coverage and relevance. Results were compared with Australian data. Results: Questionnaires were completed by 64 European patients. The module was found to be relevant and culturally acceptable to participants. Feedback has led to minor translation modifications and the inclusion of two additional questions. Conclusion: This module is ready for Phase IV testing which will consist of large scale field testing with the aim to perform psychometric analysis and finalise a module that will be suitable in the assessment of radiation induced proctitis.

  16. Radiation-induced cell transformation: transformation efficiencies of different types of ionizing radiation and molecular changes in radiation transformants and tumor cell lines.

    OpenAIRE

    Hieber, L; Trutschler, K; Smida, J. (Jan); Wachsmann, M.; Ponsel, G; Kellerer, Albrecht M.

    1990-01-01

    This study aims to compare the efficiencies of 5.4 keV soft X-rays, alpha-particles, and gamma-rays in transforming C3H 10T1/2 cells and to assess the sequence of cellular and molecular changes during the process of radiation-induced transformation of Syrian hamster embryo (SHE) cells. The somewhat more densely ionizing soft X-rays are more effective than gamma-rays both for cell inactivation and cell transformation. The relative biological effectiveness (RBE) appears to be independent of dos...

  17. Estimated Radiation on Mars, Hits per Cell Nucleus

    Science.gov (United States)

    2002-01-01

    This global map of Mars shows estimates for amounts of high-energy-particle cosmic radiation reaching the surface, a serious health concern for any future human exploration of the planet.The estimates are based on cosmic-radiation measurements made on the way to Mars by the Mars radiation environment experiment, an instrument on NASA's 2001 Mars Odyssey spacecraft, plus information about Mars' surface elevations from the laser altimeter instrument on NASA's Mars Global Surveyor. The areas of Mars expected to have least radiation are where elevation is lowest, because those areas have more atmosphere above them to block out some of the radiation. Earth's thick atmosphere shields us from most cosmic radiation, but Mars has a much thinner atmosphere than Earth does.Colors in the map refer to the estimated average number of times per year each cell nucleus in a human there would be hit by a high-energy cosmic ray particle. The range is generally from two hits (color-coded green), a moderate risk level, to eight hits (coded red), a high risk level.NASA's Jet Propulsion Laboratory, Pasadena, Calif. manages the 2001 Mars Odyssey and Mars Global Surveyor missions for NASA's Office of Space Science, Washington D.C. The Mars radiation environment experiment was developed by NASA's Johnson Space Center. Lockheed Martin Astronautics, Denver, is the prime contractor for Odyssey, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  18. Ionizing Radiation Exposure and Basal Cell Carcinoma Pathogenesis.

    Science.gov (United States)

    Li, Changzhao; Athar, Mohammad

    2016-03-01

    This commentary summarizes studies showing risk of basal cell carcinoma (BCC) development in relationship to environmental, occupational and therapeutic exposure to ionizing radiation (IR). BCC, the most common type of human cancer, is driven by the aberrant activation of hedgehog (Hh) signaling. Ptch, a tumor suppressor gene of Hh signaling pathway, and Smoothened play a key role in the development of radiation-induced BCCs in animal models. Epidemiological studies provide evidence that humans exposed to radiation as observed among the long-term, large scale cohorts of atomic bomb survivors, bone marrow transplant recipients, patients with tinea capitis and radiologic workers enhances risk of BCCs. Overall, this risk is higher in Caucasians than other races. People who were exposed early in life develop more BCCs. The enhanced IR correlation with BCC and not other common cutaneous malignancies is intriguing. The mechanism underlying these observations remains undefined. Understanding interactions between radiation-induced signaling pathways and those which drive BCC development may be important in unraveling the mechanism associated with this enhanced risk. Recent studies showed that Vismodegib, a Smoothened inhibitor, is effective in treating radiation-induced BCCs in humans, suggesting that common strategies are required for the intervention of BCCs development irrespective of their etiology. PMID:26930381

  19. Radiation redux: reserve intestinal stem cells miss the call to duty.

    Science.gov (United States)

    Shivdasani, Ramesh A

    2014-02-01

    Distinct stem cell populations in intestinal crypts mediate tissue homeostasis and responses to epithelial damage such as radiation. Now in Cell Stem Cell, Metcalfe et al. (2014) demonstrate that homeostatic, proliferative Lrg5(+) cells are necessary to regenerate the epithelium after radiation, whereas quiescent Lgr5(-) reserve stem cells are surprisingly radiosensitive. PMID:24506878

  20. Determination of inherent and additional filtration in order to establish radiation qualities according to IEC 61267

    International Nuclear Information System (INIS)

    In order to establish the radiation qualities recommended do the IEC 61267 to diagnostic radiology calibration, it was determined the inherent and additional filtration of an X rays system at the Calibration Laboratory of IPEN. To determine the inherent filtration it was used the methodology recommended by the norm ISO 4037-1. The HVL found was 0.1 mmAl. After that, using the published data at the ISO 4037-1, it was calculated the inherent filtration correspondent to this HVL, by extrapolation method. The inherent filtration found was 0.138 mmAl. To determine the additional filtration necessary to get each one of the RQR radiation qualities, according to IEC 61267, it is necessary to make an attenuation curve with no filtration. After that a transparent rectangle template representing the first and the second HVL, correspondent to the specific RQR, was made and it was slid through the curve. When the edges of the rectangle fit the curve, it is found the additional filtration to the specific radiation quality. This procedure was applied to each radiation quality from 40 to 150 kV. According to the IEC 61267, after the additional filtration determination, the correspondent HVL must be added and the relation between the values obtained with and without this HVL must be from 0.485 and 0.515. In this work all obtained values were inside this range, nevertheless, a fine adjustment was made in order to get a relation of 0.500. The obtained additional filtration to the RQR qualities was from 2.3 mmAl to 4.2 mmAl. (author)

  1. Investigation of bias radiation effect on PV cell measurement

    Science.gov (United States)

    Huang, Xuebo; Quan, Chenggen; Chan, Joanne; Ng, Patrick

    2013-06-01

    Photovoltaic (PV) cells are photo-electrical devices that convert light energy directly into electricity through the photovoltaic effect. PV cell assemblies are used to make solar modules employed in a variety of ways ranging from space applications to domestic energy consumption. Characterisation and performance testing of PV cells are critical to the development of PV technologies and growth of the solar industry. As new solar products are being developed, its energy conversion efficiency and other critical parameters must be accurately measured and tested against globally recognised metrological standards. The differential spectral responsivity (DSR) measurement is one of the primary methods for calibrating reference PV cells. This is done by calculating its spectral responsivities through measuring the AC short-circuit current produced by a PV cell under a modulated monochromatic radiation and different levels of steady-state broadband bias light radiation. It is observed that different types of bias light source will produce different signal-to-noise levels and significantly influence measurement accuracy. This paper aims to investigate the noise sources caused by different types of bias light sources (e.g. xenon arc and tungsten-halogen lamps) and the relevant measurement uncertainties so as to propose a guideline for selection of bias light source which can improve the signal-to-noise level and measurement uncertainty. The DSRs of the PV cells are measured using a commercial DSR measurement system under different levels of bias radiation from 0 to 1 kWm-2. The data analysis and uncertainty evaluation are presented in this paper using experimental data and mathematical tools.

  2. Penetrating radiation as a tool for quality evaluation of nuclear fuels

    International Nuclear Information System (INIS)

    Radiography is a universally accepted non-destructive evaluation technique for checking internal details of sealed components. Imaging nuclear fuels pose problems because of the high radiation attenuation of fuel materials. Radiography of nuclear fuels by penetrating radiations viz. X-rays, gamma rays and neutron is employed in the quality control of such fuels. This paper records the experience gathered during the inspection of nuclear fuel elements of different types fabricated at Radiometallurgy Division, B.A.R.C. and presents a comparative study of these three techniques in revealing inner details of nuclear fuels. (author)

  3. Data Quality Objectives Supporting the Environmental Direct Radiation Monitoring Program for the INL Site

    Energy Technology Data Exchange (ETDEWEB)

    Lundell, J. F. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Magnuson, S. O. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Scherbinske, P. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Case, M. J. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-07-01

    This document presents the development of the data quality objectives (DQOs) for the Idaho National Laboratory (INL) Environmental Direct Radiation Monitoring Program and follows the Environmental Protection Agency (EPA) DQO process (EPA 2006). This document also develops and presents the logic to determine the specific number of direct radiation monitoring locations around INL facilities on the desert west of Idaho Falls and in Idaho Falls, at locations bordering the INL Site, and in the surrounding regional area. The selection logic follows the guidance from the Department of Energy (DOE) (2015) for environmental surveillance of DOE facilities.

  4. Tinnitus and cell phones: the role of electromagnetic radiofrequency radiation

    OpenAIRE

    Luisa Nascimento Medeiros; Tanit Ganz Sanchez

    2016-01-01

    ABSTRACT INTRODUCTION: Tinnitus is a multifactorial condition and its prevalence has increased on the past decades. The worldwide progressive increase of the use of cell phones has exposed the peripheral auditory pathways to a higher dose of electromagnetic radiofrequency radiation (EMRFR). Some tinnitus patients report that the abusive use of mobiles, especially when repeated in the same ear, might worsen ipsilateral tinnitus. OBJECTIVE: The aim of this study was to evaluate the availabl...

  5. Radiation-resistant B-1 cells: A possible initiating cells of neoplastic transformation.

    Science.gov (United States)

    Guimarães-Cunha, Caroline Ferreira; Alvares-Saraiva, Anuska Marcelino; de Souza Apostolico, Juliana; Popi, Ana Flavia

    2016-07-01

    The role of B-1 cells in the hyperproliferative hematologic disease has been described. Several reports bring evidences that B-1 cells are the main cell population in the chronic lymphatic leukemia. It is also described that these cells have an important involvement in the lupus erythematous systemic. The murine model used to investigate both disease models is NZB/NZW. Data from literature point that mutation in micro-RNA 15a and 16 are the responsible for the B-1 hyperplasia in these mice. Interestingly, it was demonstrated that NZB/NZW B-1 cells are radioresistant, contrariwise to observe in other mouse lineage derived B-1 cells and B-2 cells. However, some reports bring evidences that a small percentage of B-1 cells in healthy mice are also able to survive to irradiation. Herein, we aim to investigate the malignant potential of ionizing-radiation resistant B-1 cells in vitro. Our main goal is to establish a model that mimics the neoplastic transformation originate to a damage exposure of DNA, and not only related to intrinsic mutations. Data shown here demonstrated that radiation-resistant B-1 cells were able to survive long periods in culture. Further, these cells show proliferation index increase in relation to non-irradiated B-1 cells. In addition, radiation resistant B-1 cells showed hyperploid, morphologic alterations, increased induction of apoptosis after anti-IgM stimulation. Based on these results, we could suggest that radiation resistant B-1 cells showed some modifications in that could be related to induction of malignant potential. PMID:26898918

  6. Cell phone radiation effects on cytogenetic abnormalities of oral mucosal cells

    OpenAIRE

    Natália Batista DAROIT; Visioli, Fernanda; Alessandra Selinger MAGNUSSON; Geila Radunz VIEIRA; Rados, Pantelis Varvaki

    2015-01-01

    The aim of this study was to evaluate the effects of exposure to cell phone electromagnetic radiation on the frequency of micronuclei, broken eggs cells, binucleated cells, and karyorrhexis in epithelial cells of the oral mucosa. The sample was composed of 60 cell phone users, who were non-smokers and non-drinkers, and had no clinically visible oral lesions. Cells were obtained from anatomical sites with the highest incidence of oral cancer: lower lip, border of the tongue, and floor of the m...

  7. Nuclear thread bridging the sister cells prior to radiation-induced cell fusion

    International Nuclear Information System (INIS)

    Intercellular protoplasmic bridges between sister cells prior to radiation-induced cell fusion were examined by various methods which included time-lapse photography, chemical staining, autoradiography, and scanning electron microscopy. It was concluded that these bridges contained nuclear material and that fusion occurred mainly as a consequence of chromosome or chromatin bridges

  8. UVB radiation induced effects on cells studied by FTIR spectroscopy

    CERN Document Server

    Di Giambattista, Lucia; Gaudenzi, S; Pozzi, D; Grandi, M; Morrone, S; Silvestri, I; Castellano, A Congiu; 10.1007/s00249-009-0446-9

    2010-01-01

    We have made a preliminary analysis of the results about the eVects on tumoral cell line (lymphoid T cell line Jurkat) induced by UVB radiation (dose of 310 mJ/cm^2) with and without a vegetable mixture. In the present study, we have used two techniques: Fourier transform infrared spectroscopy (FTIR) and flow cytometry. FTIR spectroscopy has the potential to provide the identiWcation of the vibrational modes of some of the major compounds (lipid, proteins and nucleic acids) without being invasive in the biomaterials. The second technique has allowed us to perform measurements of cytotoxicity and to assess the percentage of apoptosis. We already studied the induction of apoptotic process in the same cell line by UVB radiation; in particular, we looked for correspondences and correlations between FTIR spetroscopy and flow cytometry data finding three highly probable spectroscopic markers of apoptosis (Pozzi et al. in Radiat Res 168:698-705, 2007). In the present work, the results have shown significant changes ...

  9. Hypoxic cell sensitizers and heavy charged-particle radiations

    International Nuclear Information System (INIS)

    Stationary-phase populations of Chinese hamster V-79 cells were irradiated with 250 kV X-rays and the Bragg peaks (spread to a width of 4 cm) of energetic He-, C-, Ne-, and A-ion beams produced at the 184-inch cyclotron and BEVALAC ar Lawrence Berkeley Laboratory. Survival curves were generated with each radiation for cells suspended in air-saturated and nitrogen-saturated medium with and without sensitizer present. The oxygen enhancement ratios (OERs) measured for X-rays with 1 mM metronidazole and 0.5 nM misonidazole were 2.0 and 1.6 respectively. The OERs without sensitizer for He-,C-, Ne-, and A-ion Bragg peaks were 2.4, 1.7, 1.6 and 1.4 respectively. For each type of radiation tested the presence of hypoxic-cell sensitizers resulted in an additional reduction in the measured OERs, indicating that these drugs should be of benefit in the radiotherapy planned with these and other high LET radiations. (author)

  10. Ultrasonic radiation to enable improvement of direct methanol fuel cell.

    Science.gov (United States)

    Wu, Chaoqun; Wu, Jiang; Luo, Hao; Wang, Sanwu; Chen, Tao

    2016-03-01

    To improve DMFC (direct methanol fuel cell) performance, a new method using ultrasonic radiation is proposed and a novel DMFC structure is designed and fabricated in the present paper. Three ultrasonic transducers (piezoelectric transducer, PZT) are integrated in the flow field plate to form the ultrasonic field in the liquid fuel. Ultrasonic frequency, acoustic power, and methanol concentration have been considered as variables in the experiments. With the help of ultrasonic radiation, the maximum output power and limiting current of cell can be independently increased by 30.73% and 40.54%, respectively. The best performance of DMFC is obtained at the condition of ultrasonic radiation (30 kHz and 4 W) fed with 2M methanol solution, because both its limiting current and output power reach their maximum value simultaneously (222 mA and 33.6 mW, respectively) under this condition. These results conclude that ultrasonic can be an alternative choice for improving the cell performance, and can facilitate a guideline for the optimization of DMFC. PMID:26585016

  11. The sensitivity of human mesenchymal stem cells to ionizing radiation

    International Nuclear Information System (INIS)

    Purpose: Recent studies have shown that mesenchymal stem cells (MSCs) obtained from bone marrow transplantation patients originate from the host. This clinical observation suggests that MSCs in their niches could be resistant to irradiation. However, the biologic responses of bone marrow MSCs to irradiation have rarely been described in the literature. Methods and Materials: In this study, human bone marrow-derived, clonally expanded MSCs were used to investigate their sensitivity to irradiation in vitro, and the cellular mechanisms that may facilitate resistance to irradiation. The human lung cancer cell line A549 and the breast cancer cell line HCC1937 were used as controls for radiosensitivity; the former line has been shown to be radioresistant and the latter radiosensitive. We then examined their in vitro biologic changes and sensitivities to radiation therapy. Results: Our results suggest that MSCs are characterized as resistant to irradiation. Several cellular mechanisms were demonstrated that may facilitate resistance to irradiation: ATM protein phosphorylation, activation of cell-cycle checkpoints, double-strand break repair by homologous recombination and nonhomologous end joining (NHEJ), and the antioxidant capacity for scavenging reactive oxygen species. Conclusions: As demonstrated, MSCs possess a better antioxidant reactive oxygen species-scavenging capacity and active double-strand break repair to facilitate their radioresistance. These findings provide a better understanding of radiation-induced biologic responses in MSCs and may lead to the development of better strategies for stem cell treatment and cancer therapy

  12. Radiation effects of 60C in peritoneal cells

    International Nuclear Information System (INIS)

    This work deals with the effect of 60Co gamma irradiation on the levels and quality of peritoneal cells of albino mice. The cells were obtained from peritoneal exudate, fixed and stained in 30% glacial acetic acid containing 0.5% cristal violet. On exudates from irradiated and control animals the qualitative analysis and the counting of different cell populations were performed one hour, three days and six days after irradiation with 9 Gy. All the cell populations from the peritoneal exudate shown a decrease 3 days after the irradiation with 9.0 Gy but the different cellular populations diminished in unlike proportions. The data reaffirm the discrepance in radiosensivity of the diverse peritoneal cell populations. (author)

  13. Effect of 60Co radiation on peritoneal cells

    International Nuclear Information System (INIS)

    This work deals with the effect of 60Co gamma irradiation on the levels and quality of peritoneal cells of albino mice. The cells were obtained from peritoneal exudate, fixed and stained in 30% glacial acetic acid containing 0,5% cristal violet. Os exudates from irradiated and control animals the qualitative analysis and the counting of different cell populations were performed one hour, three days and six days after irradiation with 9 Gy. All the cell populations from the peritoneal exudate shown a decrease 3 days after the irradiation with 9.0. Gy but the different cellular populations dimished in unlike proportions. The data reaffirm the discrepance in radiosensivity of the diverse peritoneal cell populations. (author)

  14. The Effect of 5-FU and Radiation on A549 Cells In Vitro

    International Nuclear Information System (INIS)

    Effects of ionizing radiation alone and combined with chemotherapy on tumor growth and it clonal specificity Monitored by changes in distribution of chromosome number were studies in A549 cell line originated from human adenocarcinoma of the lung. Radiation (300 rad, 600 rad and 900 rad) were delivered with or without 5-FU. Forty eight hours later, 57.5% of growth inhibition of cell was Seen in cells treated with 5-FU concentration of 0.47g/ml for 24 hr exposure. Cell survival carves after radiation with and without 5-FU were made. Chromosomal analysis of cells in metaphase in control, and in cells treated with 300 rad of radiation, or 0.47g/ml of 5-FU treatment, and combined treatment of cloth were 77ne to examine the changes in ploidy and number of chromosome. Radiation combined with 5-FU enhanced growth inhibition of A549 cells. However, no evidence of synergetic effects in growth inhibition was observed in the cells treated with the combination therapy. Pattern of chromosomal distribution of survived cells were shifted from hyperploidy to hypoploidy by single dose of radiation(300 rad). As radiation dose increased a large number of hypoploidy cells were observed. Following treatment of cells with 5-FU, chomosomal distribution of survived cells were also shifted to hypodiploidy, which were seen in cells treated with radiation. The cell treated with 5-FU and followed by radiation within 24 hrs had cell with increased number of hypodiploidy cells. Almost same type of chromosomal changes were reproduced in cells treated with combined treatment with radiation and 5-FU. Minor differences were that cells with fewer number of chromosome were more frequent in cells treated with combined therapy. Further increase in cells of hypoploidy(93%) having 1-10 chromosome were induced by additional radiation. Therefore, the enhanced therapeutic effect of 5-FU combined with radiation of A549 cells appeared to be additive rather than synergistic

  15. Durability Quality Research of Concrete Containing Solar PV Cells

    OpenAIRE

    Chao Sao-Jeng; Cheng An; Hsu Hui-Mi; Chang Jia-Ruey; Teng Li-Wei; Chen Sung-Ching

    2015-01-01

    In this article we demonstrated the study results of durability quality of concrete containing waste solar PV cells. The study used alkali activator to improve the activity of alkali-activated materials in solar PV cells so as to replace Portland cement as binder in concrete. By using sodium hydroxide as an alkali-activator, a high-pH environment is generated to excite the binding characteristics of alkali-activated materials in solar PV cells, and thus develops better durability of the mixes...

  16. Radiation response of spermatogonial stem cells in the mouse

    International Nuclear Information System (INIS)

    Spermatogonial stem cells are able to repopulate the testis by forming clones that elongate along the walls of the seminiferous tubules depleted of spermatogenetic cells as a result of an irradiation. The surviving number of stem cells after irradiation was estimated by determining the fraction of repopulated tubules in cross-sections of the testis 11 weeks after irradiation. This fraction, called the 'repopulation index', is assumed to be directly proportional to the number of surviving stem cells. The response of spermatogonial stem cells in the CBA mouse to 1-MeV fission neutrons was investigated. Radioresistant, colony forming stem cells in the mouse testis move into a much more radiosensitive phase of their cell cycle shortly after irradiation. This is demonstrated in publication II in experiments in which total doses of 300 rad of neutrons and 1200 rad of X-rays were split into two equal fractions. The radiation response of spermatogonial stem cells in the mouse which survived various doses of fission neutrons 24 hours before was studied in publication III. Twenty four hours after a dose of 150 rad of fission neutrons all first-dose survivors have moved from a radioresistant (D0 89+-4 rad in this study) towards a radiosensitive phase of their cell cycle. Spermatogonial stem cells which survive a neutron dose of 150 rad all belong to a radioresistant stem cell population in the seminiferous epithelium. The data in publication IV show that during the first 26 days after a dose of 150 rad of neutrons the stem cell population first increases and then slowly decreases its radiosensitivity, to stay fixed at a relatively high level. (Auth.)

  17. Correlation between required quality assurance equipment and radiation therapy institutional level

    International Nuclear Information System (INIS)

    Radiotherapy institutions carry out various types of treatments such as conventional radiation treatment, stereotactic radiotherapy (SRT), intensity-modulated radiation therapy (IMRT) and image-guided radiotherapy (IGRT). According to the radiation treatment type, various kinds of quality assurance (QA) equipment are used to maintain the accurate dose delivery to a patient with accurate positioning. The aim of this report was to propose the QA equipment required at various institutional levels. The institution levels were categorized according to the radiation treatment cases. Institutions in the basic category used conventional radiotherapy techniques employing field sizes larger than 4 cm x 4 cm, or they had no full-time radiation oncologist. In addition to the basic level, five other categories were defined which were based on being able to carry out total body irradiation, three-dimensional conformal radiation therapy/SRT, IMRT, and IGRT. Minimum QA equipment requirements were proposed for each level. This proposal will facilitate the purchase of QA equipment for the installation or refurbishing of a linear accelerator. (author)

  18. Prognostic Cell Biological Markers in Cervical Cancer Patients Primarily Treated With (Chemo)radiation: A Systematic Review

    International Nuclear Information System (INIS)

    The aim of this study was to systematically review the prognostic and predictive significance of cell biological markers in cervical cancer patients primarily treated with (chemo)radiation. A PubMed, Embase, and Cochrane literature search was performed. Studies describing a relation between a cell biological marker and survival in ≥50 cervical cancer patients primarily treated with (chemo)radiation were selected. Study quality was assessed, and studies with a quality score of 4 or lower were excluded. Cell biological markers were clustered on biological function, and the prognostic and predictive significance of these markers was described. In total, 42 studies concerning 82 cell biological markers were included in this systematic review. In addition to cyclooxygenase-2 (COX-2) and serum squamous cell carcinoma antigen (SCC-ag) levels, markers associated with poor prognosis were involved in epidermal growth factor receptor (EGFR) signaling (EGFR and C-erbB-2) and in angiogenesis and hypoxia (carbonic anhydrase 9 and hypoxia-inducible factor-1α). Epidermal growth factor receptor and C-erbB-2 were also associated with poor response to (chemo)radiation. In conclusion, EGFR signaling is associated with poor prognosis and response to therapy in cervical cancer patients primarily treated with (chemo)radiation, whereas markers involved in angiogenesis and hypoxia, COX-2, and serum SCC-ag levels are associated with a poor prognosis. Therefore, targeting these pathways in combination with chemoradiation may improve survival in advanced-stage cervical cancer patients.

  19. Quality control beam of radiation through imaging system using a flat panel (ILD)

    International Nuclear Information System (INIS)

    The daily quality checks of the accelerator include, among others, checks of the daily calibration, symmetry and uniformity of the radiation beam. Usually verification systems daily are used for this purpose, which employ arrays of detectors of solid-state or ionization chambers. This paper intends to carry out the control of quality through the irradiation of a number of fields in the portal imaging system and its subsequent analysis in software's own creation, as well as the comparison of results with the daily verification system. (Author)

  20. Effect of lazer radiation on Chinese hamster cells cultured in vitro

    International Nuclear Information System (INIS)

    Helium-neon (lambda=633 nm) and neodymium (lambda=534 nm) lazer radiation as well as monochromatic radiation of non-lazer sources (540 and 630 nm) produced a stimulatory effect on the survival rate of Chinese hamster cells. It was shown that the stimulatory effect is related mainly to the action of radiation on the adhesive poperties of cells. With the combined action of X- and lazer-radiation the deleterious effect of X-radiation is reduced

  1. Evaluating Cell Processes, Quality, and Biomarkers in Pluripotent Stem Cells Using Video Bioinformatics.

    Science.gov (United States)

    Zahedi, Atena; On, Vincent; Lin, Sabrina C; Bays, Brett C; Omaiye, Esther; Bhanu, Bir; Talbot, Prue

    2016-01-01

    There is a foundational need for quality control tools in stem cell laboratories engaged in basic research, regenerative therapies, and toxicological studies. These tools require automated methods for evaluating cell processes and quality during in vitro passaging, expansion, maintenance, and differentiation. In this paper, an unbiased, automated high-content profiling toolkit, StemCellQC, is presented that non-invasively extracts information on cell quality and cellular processes from time-lapse phase-contrast videos. Twenty four (24) morphological and dynamic features were analyzed in healthy, unhealthy, and dying human embryonic stem cell (hESC) colonies to identify those features that were affected in each group. Multiple features differed in the healthy versus unhealthy/dying groups, and these features were linked to growth, motility, and death. Biomarkers were discovered that predicted cell processes before they were detectable by manual observation. StemCellQC distinguished healthy and unhealthy/dying hESC colonies with 96% accuracy by non-invasively measuring and tracking dynamic and morphological features over 48 hours. Changes in cellular processes can be monitored by StemCellQC and predictions can be made about the quality of pluripotent stem cell colonies. This toolkit reduced the time and resources required to track multiple pluripotent stem cell colonies and eliminated handling errors and false classifications due to human bias. StemCellQC provided both user-specified and classifier-determined analysis in cases where the affected features are not intuitive or anticipated. Video analysis algorithms allowed assessment of biological phenomena using automatic detection analysis, which can aid facilities where maintaining stem cell quality and/or monitoring changes in cellular processes are essential. In the future StemCellQC can be expanded to include other features, cell types, treatments, and differentiating cells. PMID:26848582

  2. Evaluating Cell Processes, Quality, and Biomarkers in Pluripotent Stem Cells Using Video Bioinformatics.

    Directory of Open Access Journals (Sweden)

    Atena Zahedi

    Full Text Available There is a foundational need for quality control tools in stem cell laboratories engaged in basic research, regenerative therapies, and toxicological studies. These tools require automated methods for evaluating cell processes and quality during in vitro passaging, expansion, maintenance, and differentiation. In this paper, an unbiased, automated high-content profiling toolkit, StemCellQC, is presented that non-invasively extracts information on cell quality and cellular processes from time-lapse phase-contrast videos. Twenty four (24 morphological and dynamic features were analyzed in healthy, unhealthy, and dying human embryonic stem cell (hESC colonies to identify those features that were affected in each group. Multiple features differed in the healthy versus unhealthy/dying groups, and these features were linked to growth, motility, and death. Biomarkers were discovered that predicted cell processes before they were detectable by manual observation. StemCellQC distinguished healthy and unhealthy/dying hESC colonies with 96% accuracy by non-invasively measuring and tracking dynamic and morphological features over 48 hours. Changes in cellular processes can be monitored by StemCellQC and predictions can be made about the quality of pluripotent stem cell colonies. This toolkit reduced the time and resources required to track multiple pluripotent stem cell colonies and eliminated handling errors and false classifications due to human bias. StemCellQC provided both user-specified and classifier-determined analysis in cases where the affected features are not intuitive or anticipated. Video analysis algorithms allowed assessment of biological phenomena using automatic detection analysis, which can aid facilities where maintaining stem cell quality and/or monitoring changes in cellular processes are essential. In the future StemCellQC can be expanded to include other features, cell types, treatments, and differentiating cells.

  3. Bimodal cell death induced by high radiation doses in the radioresistant sf9 insect cell line

    International Nuclear Information System (INIS)

    Full text: This study was conducted to investigate the mode(s) of cell death induced by high radiation doses in the highly radioresistant Sf9 insect ovarian cell line. Methods: Cells were exposed to γ-radiation doses 200Gy and 500Gy, harvested at various time intervals (6h-72h) following irradiation, and subjected to cell morphology assay, DNA agarose gel electrophoresis, single cell gel electrophoresis (SCGE; comet assay) and Annexin-V labeling for the detection of membrane phosphatidylserine externalization. Cell morphology was assessed in cells entrapped and fixed in agarose gel directly from the cell suspension, thus preventing the possible loss of fragments/ apoptotic bodies. Surviving fraction of Sf9 cells was 0.01 at 200Gy and 98%) undergoing extensive DNA fragmentation at 500Gy, whereas the frequency of cells with DNA fragmentation was considerably less (∼12%) at 200Gy. Conclusions: While the mode of cell death at 200Gy seems to be different from typical apoptosis, a dose of 500Gy induced bimodal cell death, with typical apoptotic as well as the atypical cell death observed at 200Gy

  4. Radiation-induced DNA double strand breaks in Ehrlich ascites tumour cells and their possible effects on cell survival

    International Nuclear Information System (INIS)

    A method to prepare high-molecular, pure DNA with the aid of enzymes, detergents, and heat treatment is presented. A sedimentation technique with neutral density gradients has been introduced which permits mass separation and molecular mass analysis of high-molecular DNA (msub(r) 10). Using this method, the induction of DNA double strand breaks (DSB) in the dose range between 10 Gy <= D <= 100 Gy has been measured. Further, the induction of DSB in dependence of the radiation quality has been studied. A correlation between DSB induction and cell survival was not found for any type of radiation investigated. DNA repair was measured in a multitude of repair conditions. The repair kinetics shows that the ''apparent'' DNA fraction is negligible. A large number of DSB was found to be repaired. The effects of some repair inhibitors have been investigated. DSB repair after cell plating on agar was proved. This factor has been underestimated in all former estimates of DSB influence on cell survival. It has been shown that DSB in living cells cannot be tolerated. There was no indication of biologically irrelevant DSB. (orig./AJ)

  5. Interactions between endothelial cells and T cells modulate responses to mixed neutron/gamma radiation.

    Science.gov (United States)

    Cary, Lynnette H; Noutai, Daniel; Salber, Rudolph E; Williams, Margaret S; Ngudiankama, Barbara F; Whitnall, Mark H

    2014-06-01

    Detonation of an improvised nuclear device near a population center would cause significant casualties from the acute radiation syndrome (ARS) due to exposure to mixed neutron/gamma fields (MF). The pathophysiology of ARS involves inflammation, microvascular damage and alterations in immune function. Interactions between endothelial cells (EC) and hematopoietic cells are important not only for regulating immune cell traffic and function, but also for providing the microenvironment that controls survival, differentiation and migration of hematopoietic stem and progenitor cells in blood-forming tissues. Endothelial cells/leukocyte interactions also influence tumor progression and the results of anticancer therapies. In this study, we hypothesized that irradiation of endothelial cells would modulate their effects on hematopoietic cells and vice versa. Human umbilical vein endothelial cells (HUVEC) and immortalized T lymphocytes (Jurkat cells) were cultured individually and in co-culture after exposure to mixed fields. Effects of nonirradiated cells were compared to effects of irradiated cells and alterations in signaling pathways were determined. Mitogen-activated protein kinases (MAPKs) p38 and p44/42 (ERK1/2) in HUVEC exhibited higher levels of phosphorylated protein after exposure to mixed field radiation. IL-6, IL-8, G-CSF, platelet derived growth factor (PDGF) and angiopoietin 2 (ANG2) protein expression were upregulated in HUVEC by exposure to mixed field radiation. PCR arrays using HUVEC mRNA revealed alterations in gene expression after exposure to mixed fields and/or co-culture with Jurkat cells. The presence of HUVEC also influenced the function of Jurkat cells. Nonirradiated Jurkat cells showed an increase in proliferation when co-cultured with nonirradiated HUVEC, and a decrease in proliferation when co-cultured with irradiated HUVEC. Additionally, nonirradiated Jurkat cells incubated in media from irradiated HUVEC exhibited upregulation of activated

  6. Quantification of an External Motion Surrogate for Quality Assurance in Lung Cancer Radiation Therapy

    OpenAIRE

    2014-01-01

    The purpose of this work was to validate the stability of the end exhale position in deep expiration breath hold (DEBH) technique for quality assurance in stereotactic lung tumor radiation therapy. Furthermore, a motion analysis was performed for 20 patients to evaluate breathing periods and baseline drifts based on an external surrogate. This trajectory was detected using stereo infrared (IR) cameras and reflective body markers. The respiratory waveform showed large interpatient differences ...

  7. Effect of γ radiation processing on fungal growth and quality characteristcs of millet grains.

    Science.gov (United States)

    Mahmoud, Nagat S; Awad, Sahar H; Madani, Rayan M A; Osman, Fahmi A; Elmamoun, Khalid; Hassan, Amro B

    2016-05-01

    The aim of this study was to evaluate the effect of gamma radiation processing of millet grains on fungal incidence, germination, free fatty acids content, protein solubility, digestible protein, and antinutritional factors (tannin and phytic acid). The grains were exposed to gamma radiation at doses 0.25, 0.5, 0.75, 1.0, and 2.0 kGy. Obtained results revealed that radiation of millet grains at a dose level higher than 0.5 kGy caused significant (P phytic acid content and gradual increment on in vitro protein digestibility of the grains. On the other hand, the treatments significantly (P < 0.05) increased the protein solubility of the grains. Obtained results indicate that gamma irradiation might improve the quality characteristics of millet grains, and can be used as a postharvest method for disinfestations and decontamination of millet grains. PMID:27247763

  8. Effect of ionizing radiation on human skeletal muscle precursor cells

    International Nuclear Information System (INIS)

    Long term effects of different doses of ionizing radiation on human skeletal muscle myoblast proliferation, cytokine signalling and stress response capacity were studied in primary cell cultures. Human skeletal muscle myoblasts obtained from muscle biopsies were cultured and irradiated with a Darpac 2000 X-ray unit at doses of 4, 6 and 8 Gy. Acute effects of radiation were studied by interleukin – 6 (IL-6) release and stress response detected by the heat shock protein (HSP) level, while long term effects were followed by proliferation capacity and cell death. Compared with non-irradiated control and cells treated with inhibitor of cell proliferation Ara C, myoblast proliferation decreased 72 h post-irradiation, this effect was more pronounced with increasing doses. Post-irradiation myoblast survival determined by measurement of released LDH enzyme activity revealed increased activity after exposure to irradiation. The acute response of myoblasts to lower doses of irradiation (4 and 6 Gy) was decreased secretion of constitutive IL-6. Higher doses of irradiation triggered a stress response in myoblasts, determined by increased levels of stress markers (HSPs 27 and 70). Our results show that myoblasts are sensitive to irradiation in terms of their proliferation capacity and capacity to secret IL-6. Since myoblast proliferation and differentiation are a key stage in muscle regeneration, this effect of irradiation needs to be taken in account, particularly in certain clinical conditions

  9. Acquired Tumor Cell Radiation Resistance at the Treatment Site Is Mediated Through Radiation-Orchestrated Intercellular Communication

    Energy Technology Data Exchange (ETDEWEB)

    Aravindan, Natarajan, E-mail: naravind@ouhsc.edu [Department of Radiation Oncology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (United States); Aravindan, Sheeja; Pandian, Vijayabaskar; Khan, Faizan H.; Ramraj, Satish Kumar; Natt, Praveen [Department of Radiation Oncology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (United States); Natarajan, Mohan [Department of Pathology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas (United States)

    2014-03-01

    Purpose: Radiation resistance induced in cancer cells that survive after radiation therapy (RT) could be associated with increased radiation protection, limiting the therapeutic benefit of radiation. Herein we investigated the sequential mechanistic molecular orchestration involved in radiation-induced radiation protection in tumor cells. Results: Radiation, both in the low-dose irradiation (LDIR) range (10, 50, or 100 cGy) or at a higher, challenge dose IR (CDIR), 4 Gy, induced dose-dependent and sustained NFκB-DNA binding activity. However, a robust and consistent increase was seen in CDIR-induced NFκB activity, decreased DNA fragmentation, apoptosis, and cytotoxicity and attenuation of CDIR-inhibited clonal expansion when the cells were primed with LDIR prior to challenge dose. Furthermore, NFκB manipulation studies with small interfering RNA (siRNA) silencing or p50/p65 overexpression unveiled the influence of LDIR-activated NFκB in regulating CDIR-induced DNA fragmentation and apoptosis. LDIR significantly increased the transactivation/translation of the radiation-responsive factors tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), cMYC, and SOD2. Coculture experiments exhibit LDIR-influenced radiation protection and increases in cellular expression, secretion, and activation of radiation-responsive molecules in bystander cells. Individual gene-silencing approach with siRNAs coupled with coculture studies showed the influence of LDIR-modulated TNF-α, IL-1α, cMYC, and SOD2 in induced radiation protection in bystander cells. NFκB inhibition/overexpression studies coupled with coculture experiments demonstrated that TNF-α, IL-1α, cMYC, and SOD2 are selectively regulated by LDIR-induced NFκB. Conclusions: Together, these data strongly suggest that scattered LDIR-induced NFκB-dependent TNF-α, IL-1α, cMYC, and SOD2 mediate radiation protection to the subsequent challenge dose in tumor cells.

  10. Acquired Tumor Cell Radiation Resistance at the Treatment Site Is Mediated Through Radiation-Orchestrated Intercellular Communication

    International Nuclear Information System (INIS)

    Purpose: Radiation resistance induced in cancer cells that survive after radiation therapy (RT) could be associated with increased radiation protection, limiting the therapeutic benefit of radiation. Herein we investigated the sequential mechanistic molecular orchestration involved in radiation-induced radiation protection in tumor cells. Results: Radiation, both in the low-dose irradiation (LDIR) range (10, 50, or 100 cGy) or at a higher, challenge dose IR (CDIR), 4 Gy, induced dose-dependent and sustained NFκB-DNA binding activity. However, a robust and consistent increase was seen in CDIR-induced NFκB activity, decreased DNA fragmentation, apoptosis, and cytotoxicity and attenuation of CDIR-inhibited clonal expansion when the cells were primed with LDIR prior to challenge dose. Furthermore, NFκB manipulation studies with small interfering RNA (siRNA) silencing or p50/p65 overexpression unveiled the influence of LDIR-activated NFκB in regulating CDIR-induced DNA fragmentation and apoptosis. LDIR significantly increased the transactivation/translation of the radiation-responsive factors tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), cMYC, and SOD2. Coculture experiments exhibit LDIR-influenced radiation protection and increases in cellular expression, secretion, and activation of radiation-responsive molecules in bystander cells. Individual gene-silencing approach with siRNAs coupled with coculture studies showed the influence of LDIR-modulated TNF-α, IL-1α, cMYC, and SOD2 in induced radiation protection in bystander cells. NFκB inhibition/overexpression studies coupled with coculture experiments demonstrated that TNF-α, IL-1α, cMYC, and SOD2 are selectively regulated by LDIR-induced NFκB. Conclusions: Together, these data strongly suggest that scattered LDIR-induced NFκB-dependent TNF-α, IL-1α, cMYC, and SOD2 mediate radiation protection to the subsequent challenge dose in tumor cells

  11. Italian guidelines for quality assurance in intraoperative radiation therapy: Physical aspects

    International Nuclear Information System (INIS)

    In March 2001, the Italian Institute of Health (Istituto Superiore di Sanita), within the national project of Quality Assurance (QA) in Radiotherapy, established a multidisciplinary working group aiming at the development of guidelines in Intraoperative Radiation Therapy (IORT). The group was composed by radiation oncologists, medical physicists, radiation technologists and surgeons working in those Italian Centres experienced in the field of IORT, already performing this treatment modality in the clinical practice. A preliminary draft of the document was presented in Rome at the end of 2001. With respect tea similar report published by AAPM in 1995, in the Italian guidelines a great emphasis is assigned to mobile dedicated facilities located in the operating room, largely available in Italy in relationship to the total number of equipment used for IORT. The aim of this presentation is to discuss the main physical issues reported in the guidelines. They include the following sections: (a) beam calibration; (b) relative dosimetry; (c) quality control; (d) in vivo dosimetry; (e) environmental radiation protection; (f) monitor unit calculation

  12. Key Performance Indicators in the Evaluation of the Quality of Radiation Safety Programs.

    Science.gov (United States)

    Schultz, Cheryl Culver; Shaffer, Sheila; Fink-Bennett, Darlene; Winokur, Kay

    2016-08-01

    Beaumont is a multiple hospital health care system with a centralized radiation safety department. The health system operates under a broad scope Nuclear Regulatory Commission license but also maintains several other limited use NRC licenses in off-site facilities and clinics. The hospital-based program is expansive including diagnostic radiology and nuclear medicine (molecular imaging), interventional radiology, a comprehensive cardiovascular program, multiple forms of radiation therapy (low dose rate brachytherapy, high dose rate brachytherapy, external beam radiotherapy, and gamma knife), and the Research Institute (including basic bench top, human and animal). Each year, in the annual report, data is analyzed and then tracked and trended. While any summary report will, by nature, include items such as the number of pieces of equipment, inspections performed, staff monitored and educated and other similar parameters, not all include an objective review of the quality and effectiveness of the program. Through objective numerical data Beaumont adopted seven key performance indicators. The assertion made is that key performance indicators can be used to establish benchmarks for evaluation and comparison of the effectiveness and quality of radiation safety programs. Based on over a decade of data collection, and adoption of key performance indicators, this paper demonstrates one way to establish objective benchmarking for radiation safety programs in the health care environment. PMID:27356165

  13. International perspectives on quality assurance and new techniques in radiation medicine: outcomes of an IAEA conference.

    Science.gov (United States)

    Shortt, Ken; Davidsson, Lena; Hendry, Jolyon; Dondi, Maurizio; Andreo, Pedro

    2008-01-01

    The International Atomic Energy Agency organized an international conference called, "Quality Assurance and New Techniques in Radiation Medicine" (QANTRM). It dealt with quality assurance (QA) in all aspects of radiation medicine (diagnostic radiology, nuclear medicine, and radiotherapy) at the international level. Participants discussed QA issues pertaining to the implementation of new technologies and the need for education and staff training. The advantage of developing a comprehensive and harmonized approach to QA covering both the technical and the managerial issues was emphasized to ensure the optimization of benefits to patient safety and effectiveness. The necessary coupling between medical radiation imaging and radiotherapy was stressed, particularly for advanced technologies. However, the need for a more systematic approach to the adoption of advanced technologies was underscored by a report on failures in intensity-modulated radiotherapy dosimetry auditing tests in the United States, which could imply inadequate implementation of QA for these new technologies. A plenary session addressed the socioeconomic impact of introducing advanced technologies in resource-limited settings. How shall the dual gaps, one in access to basic medical services and the other in access to high-quality modern technology, be addressed? PMID:18406944

  14. Effect of gamma radiation on microbiological quality of shrimp paste (Kapi)

    International Nuclear Information System (INIS)

    Seven brands of shrimp paste (Kapi) sold in supermarkets were investigated for microbiological quality and quantity of salt. The effect of gamma radiation at dose 1 to 6 kGy on microbiological quality and on sensory quality of shrimp paste were also evaluated. Total viable bacterial counts of surveyed samples ranged from 1.20 x 104 to 4.00 x 105 colony forming unit (cfu) per gram and no detectable number of Enterobacteriaceae, coliforms, Faecal coliforms, Escherichia coil, Salmonella, Vibrio parahaemolyticus and Staphylococcus aureus was found. The most probable number (MPN) per gram of Clostridium perfringens is ranged from 9 to 240. Percentage of salt in surveyed shrimp pastes was rather high (ranged from 19.08 to 25.08). Radiation with 4 kGy resulted in 2 log cycles reduction of total viable bacterial counts and 2-4 log cycles reduction of halophilic bacteria, but no decrease in the most probable number per gram of CI. perfringens. A dose of 6 kGy gamma radiation was adequate for decreasing the MPN per gram of C. perfringens. No significant change in sensory scores for odour and flavor was observed in irradiated shrimp paste. Only in irradiated at dose of 6 kGy was the significant change in colour observed

  15. Virtual computed tomography colonoscopy: artifacts, image quality and radiation dose load in a cadaver study

    International Nuclear Information System (INIS)

    The purpose of our study was to evaluate the interdependency of spatial resolution, image reconstruction artifacts, and radiation doses in virtual CT colonoscopy by comparing various CT scanning protocols. A pig's colon with several artificial polypoid lesions was imaged after air insufflation with helical CT scanning using 1-, 3-, and 5-mm collimation, and pitch values varying from 1.0 to 3.0. Virtual endoscopic images and ''fly through'' sequences were calculated on a Sun Sparc 20 workstation (Navigator Software, GE Medical Systems, Milwaukee, Wis.). Several reconstruction artifacts as well as overall image quality were evaluated by three independent reviewers. In addition, radiation doses for the different CT protocols were measured as multiple-scan average dose using a 10-cm ion chamber and a standard Plexiglass body phantom. Generally, image quality and reconstruction artifacts were less affected by pitch values than by beam collimation. Thus, narrow beam collimation at higher pitch values (e. g. 3 mm/2.0) seems to be a reasonable compromise between quality of virtual endoscopic images and radiation dose load. (orig.)

  16. Quality of Life and Its Related Factors of Radiation Therapy Cancer Patients

    International Nuclear Information System (INIS)

    The purpose of this master's thesis is to utilize basic data in order to improve the quality of life of cancer patients who received radiation therapy after analysing related factors that influence patient's quality of life and obtaining information about physical, mental problems of patients. By using a structured questionnaire about various characteristics and forms of support, I carried out a survey targeting 107 patients that experienced radiation therapy at a university hospital in the Daejeon metropolitan area from July 15 to August 15, 2010 and analysed the factors influencing quality of life. In case of pain due to disease, 65.15 and painless 81.87 showed a high grade quality of life. As body weight decreases, the quality of life become lower. When the grade of quality of life according to economic characteristics was compared, all items except treatment period showed a difference (P=0.000). When the score of social support, family support, medical support and self-esteem was low, the mark of quality of life showed respectively 61.71, 68.77, 71.31, and 69.39 on the basis of 128 points. When the score of support form was high, the mark of quality of life showed 90.47, 83.29, 90.40, and 90.36 (P<0.05). When analyzing the correlation between social support, family support, medical support and self-esteem and the degree of quality of life, social support was 0.768, family support 0.596, medical support 0.434, self-esteem 0.516. They indicated the correlation of meaningful quantity statistically (P<0.01). The factors that improved the quality of life were married state, having a job and painless status. As monthly income increases, the quality of life was also much improved (P<0.05). Among the factors related to quality of life, social support and medical support and higher self-esteem scores of the quality of life score increased 0.979 point, 0.508 points and 1.667 point, respectively. In conclusion, the quality of life of cancer patients that received

  17. Quality of Life and Its Related Factors of Radiation Therapy Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Ryung Mi; Jung, Won Seok; Oh, Byeong Heon; Jo, Jun Young; Kim, Gi Chul; Choi, Tae Gyu [Dept. of Radiation Oncology, Kyunghee University Medical Center, Seoul (Korea, Republic of); Lee, Sok Goo [Dept. of Preventive Medicine, Chungnam National University College of Medicine, Daejeon (Korea, Republic of)

    2011-03-15

    The purpose of this master's thesis is to utilize basic data in order to improve the quality of life of cancer patients who received radiation therapy after analysing related factors that influence patient's quality of life and obtaining information about physical, mental problems of patients. By using a structured questionnaire about various characteristics and forms of support, I carried out a survey targeting 107 patients that experienced radiation therapy at a university hospital in the Daejeon metropolitan area from July 15 to August 15, 2010 and analysed the factors influencing quality of life. In case of pain due to disease, 65.15 and painless 81.87 showed a high grade quality of life. As body weight decreases, the quality of life become lower. When the grade of quality of life according to economic characteristics was compared, all items except treatment period showed a difference (P=0.000). When the score of social support, family support, medical support and self-esteem was low, the mark of quality of life showed respectively 61.71, 68.77, 71.31, and 69.39 on the basis of 128 points. When the score of support form was high, the mark of quality of life showed 90.47, 83.29, 90.40, and 90.36 (P<0.05). When analyzing the correlation between social support, family support, medical support and self-esteem and the degree of quality of life, social support was 0.768, family support 0.596, medical support 0.434, self-esteem 0.516. They indicated the correlation of meaningful quantity statistically (P<0.01). The factors that improved the quality of life were married state, having a job and painless status. As monthly income increases, the quality of life was also much improved (P<0.05). Among the factors related to quality of life, social support and medical support and higher self-esteem scores of the quality of life score increased 0.979 point, 0.508 points and 1.667 point, respectively. In conclusion, the quality of life of cancer patients that

  18. Kualitas Spermatozoa Mencit yang Terpapar Radiasi Sinar-X Secara Berulang (SPERMATOZOA QUALITY OF MICE EXPOSED TO X-RAYS RADIATION IN REPEATED

    Directory of Open Access Journals (Sweden)

    Ni Wayan Sudatri

    2015-05-01

    Full Text Available In radiology, X-ray has been used to diagnose disease and therapy. However, behind the technologybenefits provided by the radiation, the negative effects are often debated. The purpose of this study was toinvestigate the effects of repeated radiation on sperm quality mice (Mus musculus L. Thirty- two adultmale mice aged three months were divided into groups P1 (1x 200 rad, P2 (2x200 rad, P3 (3x200 rad andcontrol irradiated with x-rays according to the experimental design . Spermatozoa quality parametersobserved were : number of spermatozoa, motility, viability and morphology of spermatozoa. The results ofthe Post Hoc LSD tests for significant differences (P>0.05 between the control and treatment showed thatthe X-ray radiation exposure to 1x200 rad, 2x200 rad, and 3x200 rad decreases the motility, viability,normal morphology and number spermatozoa produced compared with controls. This is caused by exposureto X-ray radiation causes the formation of free radicals in the body that damage sperm cells mice. Exposureto X-ray radiation repeatedly lowered the quality of spermatozoa of mice.

  19. The influence of the cellular phone radiation on the growth of mark145 cell

    International Nuclear Information System (INIS)

    Objective: To explore the effects of radiation of cellular phone on the growth of cells. Methods: A radiation cycle was designed as working 25 minutes and then resting for 5 minutes for cellular phone. The Mark145 cell bottles were divided into six groups. The first two groups were radiated for two cycles, and the second two groups for four cycles, and the third two groups for five cycles. Each two groups were put 10cm far away from cellular phone and attach to it separately. Results: After culturing for 3 days there are many dead cells in the bottles. After culturing for 6 days, there is few living cells. Conclusions: cellular phone radiation is fatal to Mark145 cells, and the quantity of the dead cells change with the radiation time and the distance to radiation. That is to say, with the prolonging of radiation time and the shortening of the distance, the quantity of the dead cells is increasing. (authors)

  20. Radiation-induced DNA double-strand break frequencies in human squamous cell carcinoma cell lines of different radiation sensitivities

    International Nuclear Information System (INIS)

    DNA neutral (pH 9-6) filter elution was used to measure radiation-induced DNA double-strand break (dsb) frequencies in eight human squamous cell carcinoma cell lines with radiosensitivities (D0) ranging from 1.07 to 2.66 Gy and D-bar values ranging from 1.46 to 4.08 Gy. Elution profiles of unirradiated samples from more radiosensitive cell lines were all steeper in slope than profiles from resistant cells. The shapes of the dsb induction curves were curvilinear and there was some variability from cell line to cell line in the dose-response for the induction of DNA dsb after exposures to 5-100 Gy 60Co γ-rays. There was no relation between shapes of survival curves and shapes of the dose-responses for the induction of DNA dsb. At low doses (5-25 Gy), three out of four of the more sensitive cell lines (D-bar3.0 Gy). Although the low-dose (5-25 Gy) elution results were variable, they suggest that DNA neutral elution will detect differences between sensitive and resistant tumour cells in initial DNA dsb frequencies. (author)

  1. Advances in radiation biology: Radiosensitization in DNA and living cells

    Science.gov (United States)

    Lacombe, S.; Sech, C. Le

    2009-06-01

    One fundamental goal of radiation biology is the evolution of concepts and methods for the elaboration of new approaches and protocols for the treatment of cancers. In this context, the use of fast ions as ionizing particles offers the advantage of optimizing cell killing inside the tumor whilst preserving the surrounding healthy tissues. One extremely promising strategy investigated recently is the addition of radiosensitizers in the targeted tissue. The optimization of radiotherapy with fast ions implies a multidisciplinary approach to ionizing radiation effects on complex living systems, ranging from studies on single molecules to investigations of entire organisms. In this article we review recent studies on ion induced damages in simple and complex biological systems, from DNA to living cells. The specific aspect of radiosensitization induced by metallic atoms is described. As a fundamental result, the addition of sensitizing compounds with ion irradiation may improve therapeutic index in cancer therapy. In conclusion, new perspectives are proposed based on the experience and contribution of different communities including Surface Sciences, to improve the development of radiation biology.

  2. Radiation safety and quality assurance in diagnostic x-ray imaging 1999; Saeteilyturvallisuus ja laadunvarmistus roentgendiagnostiikassa 1999

    Energy Technology Data Exchange (ETDEWEB)

    Servonmaa, A. [ed.

    1999-04-01

    In the European Union, the Directive 97/43/Euratom concerning the medical use of radiation brings many new tasks to radiation users. Quality assurance, patient dose measurement, staff training and clinical audit are among the most essential of these tasks. The Finnish radiation legislation has been modified to comply with the Directive. Much work is still required for practical implementation of these rules. This report deals with applications of the medical radiation Directive. Most applications are still at the planning stage, and clear guidance is lacking. However, the users have to know in time about these plans and future duties concerning them. Experience on quality assurance and clinical audit in hospitals are especially valuable in providing practical information on benefits and problems of these practices. Other radiation related topics, such as radiation risks, radioactivity in foods, and use of radiation in other European countries, are also included in the report. (orig.)

  3. Alterations induced in Escherichia Coli cells by gamma radiation

    International Nuclear Information System (INIS)

    Modifications occurred in Escherichia coli cells exposed to gamma radiation (60Co source) were investigated. The irradiations were done at the LIN-COPPE laboratory of the UFRJ and the analysis at the Biology Department of the UTFPR. The E. coli cells were irradiated with 30, 60, 90, 120, 150, 180, 210, 240, 300, 480, 600 e 750 Gy doses. The samples were analyzed with Gram-stain, biochemical tests in EPM, MIO and Lysine Broth, Simmons Cytrate Medium and Rhamnose Broth, antibiogram and isolation of auxotrophic mutants. It was observed that for the received doses the E. coli did not show morphological alterations in the tests. Some E. Coli cells showed to be able to deaminade the L-tryptophan or they changed their sensibility for amoxillin and cephaloonine after the irradiation. The existence of aauxotrophic mutants after irradiation was also verified. (author)

  4. TH-A-16A-01: Image Quality for the Radiation Oncology Physicist: Review of the Fundamentals and Implementation

    International Nuclear Information System (INIS)

    The expansion and integration of diagnostic imaging technologies such as On Board Imaging (OBI) and Cone Beam Computed Tomography (CBCT) into radiation oncology has required radiation oncology physicists to be responsible for and become familiar with assessing image quality. Unfortunately many radiation oncology physicists have had little or no training or experience in measuring and assessing image quality. Many physicists have turned to automated QA analysis software without having a fundamental understanding of image quality measures. This session will review the basic image quality measures of imaging technologies used in the radiation oncology clinic, such as low contrast resolution, high contrast resolution, uniformity, noise, and contrast scale, and how to measure and assess them in a meaningful way. Additionally a discussion of the implementation of an image quality assurance program in compliance with Task Group recommendations will be presented along with the advantages and disadvantages of automated analysis methods. Learning Objectives: Review and understanding of the fundamentals of image quality. Review and understanding of the basic image quality measures of imaging modalities used in the radiation oncology clinic. Understand how to implement an image quality assurance program and to assess basic image quality measures in a meaningful way

  5. Collimation effects on the radiation detectors in the iCT image quality

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Diego Vergacas de Sousa; Kirita, Rodrigo; Mesquita, Carlos Henrique de; Hamada, Margarida Mizue, E-mail: dvcarvalho@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Ferreira, Erick Oliveira; Dantas, Carlos Costa [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear

    2013-07-01

    This work studies the collimation effect in radiation detectors on the image quality of the iCT scanner, in which the path traversed by radiation beams is similar to a fan. The collimators were made of lead, 5 cm deep and 12 cm high, with rectangular holes (slits) of 2 x 5 mm, 4 x 10 mm (width x height) and circular hole of 5 mm diameter. The matrix images reconstructed from the data obtained with these collimation holes are presented. The spatial resolution of the image depends on the geometry of the collimator. One of the major advantages of narrow beam transmission tomography is the so-called hard field property. This property is capable of producing high quality images, though it decreases the count value and it takes a longer time. In contrast, a large collimation diameter produces a fuzzy image but with a faster scanning time. Moreover, the enlargement of the aperture from 2 x 5 mm to 4 x 10 mm barely affects the image quality. The aperture from 4 x 10 mm and 5 mm diameter presented similar quality image. (author)

  6. Improved image quality and radiation dose reduction in liver dynamic CT scan with the protocol change

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yu Jin; Cho, Pyong Kon [Radiological Science, Catholic University of Daegu, Daegu (Korea, Republic of)

    2015-06-15

    The purpose is reducing radiation dose while maintaining of image quality in liver dynamic CT(LDCT) scan, by protocols generally used and the tube voltage set at a low level protocol compared to the radiation dose and image quality. The target is body mass index, 18.5-24 patients out of 40 patients who underwent the ACT(abdominal CT). Group A(tube voltage : 120 kVp, SAFIRE strength 1) of 20 people among 40 people, to apply the general abdominal CT scan protocol, group B(tube voltage : 100 kVp, apply SAFIRE strength 0-5) was 20 people, set a lower tube voltage. Image quality evaluation was setting a region of interest(ROI) in the liver parenchyma, aorta, superior mesenteric artery (SMA), celiac trunk, visceral fat of arterial phase. In the ROI were compared by measuring the noise, signal to noise ratio(SNR), contrast to noise ratio(CNR), CT number. In addition, qualitative assessments to evaluate two people in the rich professional experience in Radiology by 0-3 points. We compared the total radiation dose, dose length product(DLP) and effective dose, volume computed tomography dose index(CTDIvol). The higher SAFIRE in the tube voltage 100 kVp, noise is reduced, CT number was increased. Thus, SNR and CNR was increased higher the SAFIRE step. Compared with the tube voltage 120 kVp, noise, SNR, CNR was most similar in SAFIRE strength 2 and 3. Qualitative assessment SAFIRE strength 2 is the most common SAFIRE strength 2 the most common qualitative assessment, if the tube voltage of 100 kVp when the quality of the images better evaluated was SAFIRE strength 1. Dose was reduced from 21.69%, in 100 kVp than 120 kVp. In the case of a relatively high BMI is not LDCT scan, When it is shipped from the factory tube voltage is set higher, unnecessary radiation exposure when considering the reality that is concerned, when according to the results of this study, set a lower tube voltage and adjust the SAFIRE strength to 1 or 2, the radiation without compromising image quality

  7. Improved image quality and radiation dose reduction in liver dynamic CT scan with the protocol change

    International Nuclear Information System (INIS)

    The purpose is reducing radiation dose while maintaining of image quality in liver dynamic CT(LDCT) scan, by protocols generally used and the tube voltage set at a low level protocol compared to the radiation dose and image quality. The target is body mass index, 18.5-24 patients out of 40 patients who underwent the ACT(abdominal CT). Group A(tube voltage : 120 kVp, SAFIRE strength 1) of 20 people among 40 people, to apply the general abdominal CT scan protocol, group B(tube voltage : 100 kVp, apply SAFIRE strength 0-5) was 20 people, set a lower tube voltage. Image quality evaluation was setting a region of interest(ROI) in the liver parenchyma, aorta, superior mesenteric artery (SMA), celiac trunk, visceral fat of arterial phase. In the ROI were compared by measuring the noise, signal to noise ratio(SNR), contrast to noise ratio(CNR), CT number. In addition, qualitative assessments to evaluate two people in the rich professional experience in Radiology by 0-3 points. We compared the total radiation dose, dose length product(DLP) and effective dose, volume computed tomography dose index(CTDIvol). The higher SAFIRE in the tube voltage 100 kVp, noise is reduced, CT number was increased. Thus, SNR and CNR was increased higher the SAFIRE step. Compared with the tube voltage 120 kVp, noise, SNR, CNR was most similar in SAFIRE strength 2 and 3. Qualitative assessment SAFIRE strength 2 is the most common SAFIRE strength 2 the most common qualitative assessment, if the tube voltage of 100 kVp when the quality of the images better evaluated was SAFIRE strength 1. Dose was reduced from 21.69%, in 100 kVp than 120 kVp. In the case of a relatively high BMI is not LDCT scan, When it is shipped from the factory tube voltage is set higher, unnecessary radiation exposure when considering the reality that is concerned, when according to the results of this study, set a lower tube voltage and adjust the SAFIRE strength to 1 or 2, the radiation without compromising image quality

  8. Users manual for SERI QC software assessing the quality of solar radiation data

    Energy Technology Data Exchange (ETDEWEB)

    None

    1993-12-01

    This manual describes the procedures and software for assessing the quality of solar radiation data. This does not constitute quality control because quality control must take place during the preparations for data collection (selection, calibration, and installation of instruments), during the measurement process, and during the transmission (if any) and recording of the numerical values. Once the data are recorded, only quality assessment can be performed. If quality assessment is performed in real time or soon after the measurement process is completed, it can provide input to control the quality of future measurements. Furthermore, quality assessment can be used for quality control if data judged to be bad are deleted and/or modified. We do not subscribe to these actions because the deletion or modification of data destroys information that might be useful to the user. For example, if an instrument has gone through a gradual failure and all of the data that fail quality assessment criteria are deleted or modified, the user of the data may not be able to detect what was happening and will not question the accuracy of other data collected before the instrument completely failed. Therefore, the SERI QC procedures and software do not delete or modify data. Instead, flags are set to inform the user of any departure of the data from expected values. These flags indicate the magnitude and direction of such departures. For the flags to communicate as much information as possible, this manual attempts to identify and explain the probable causes of various flags. However, we cannot overemphasize the following: Flags only indicate that data do or do not fall within expected ranges. This does not mean that the data that the data are or are not valid.

  9. Gene analysis and dynamics of tumor stem cell in human glioblastoma cells after radiation

    International Nuclear Information System (INIS)

    Because glioblastoma is the most malignant central nervous system (CNS) tumor, it is very difficult to cure despite surgery and adjuvant therapy. At present, surgery, radiotherapy, and chemotherapy are combined in the treatment of each patient. However, glioblastoma have radiotherapy and chemotherapy resistance, and this is not a radical treatment. We suspect that the tumor stem cell affects the recurrence, radiotherapy resistance and chemotherapy resistance of the tumor. Many studies suggest that tumor stem cells play an important role in tumorgenesis and tumor progression. Using human glioblastoma cell lines (T98G, A172), irradiated (0 Gy, 30 Gy, 60 Gy) glioblastoma cells were prepared under the same conditions as clinical therapy. We performed the analysis of cell proliferation rate, side population analysis by fluorescence-activated cell sorter (FACS), isolation of CD133+ cells and genetic analysis (human stem cell), using these cells. In the results of this study, the stem cell-related genes were highly expressed in the CD133+ cells compared with the CD133- cells. Therefore, it suggested that the CD133+ cells may contain tumor stem cells. In T98G, when compared to unirradiated cells and 60 Gy-irradiated cells, the cell proliferation rate for 30 Gy-irradiated cells tended to be higher, and stem cell-related genes were highly expressed in 30 Gy-irradiated CD133+ cells. In other words, in T98G, from the viewpoint of antitumor effects, the results suggest that chemotherapy may show more effect in 30 Gy-irradiated. In this genetic analysis, we suggest that CD133+ cells strongly affect tumor proliferation. In addition, CD133+ cells affect the resistance and the effect of treatments because some kind of changes occur in CD133+ cells after radiation. (author)

  10. Ionizing radiation induces heritable disruption of epithelial cell interactions

    International Nuclear Information System (INIS)

    Ionizing radiation (IR) is a known human breast carcinogen. Although the mutagenic capacity of IR is widely acknowledged as the basis for its action as a carcinogen, we and others have shown that IR can also induce growth factors and extracellular matrix remodeling. As a consequence, we have proposed that an additional factor contributing to IR carcinogenesis is the potential disruption of critical constraints that are imposed by normal cell interactions. To test this hypothesis, we asked whether IR affected the ability of nonmalignant human mammary epithelial cells (HMEC) to undergo tissue-specific morphogenesis in culture by using confocal microscopy and imaging bioinformatics. We found that irradiated single HMEC gave rise to colonies exhibiting decreased localization of E-cadherin, β-catenin, and connexin-43, proteins necessary for the establishment of polarity and communication. Severely compromised acinar organization was manifested by the majority of irradiated HMEC progeny as quantified by image analysis. Disrupted cell-cell communication, aberrant cell-extracellular matrix interactions, and loss of tissue-specific architecture observed in the daughters of irradiated HMEC are characteristic of neoplastic progression. These data point to a heritable, nonmutational mechanism whereby IR compromises cell polarity and multicellular organization

  11. A study on immobilized ethanol yeast cells by radiation technique

    International Nuclear Information System (INIS)

    Hydrophilic monomer 2-hydroxyethyl acrylate (HEA) and a series of polyethylene glycol dimethacrylate monomers were copolymerized by radiation technique at low temperature (-78 degree C) and hydrophilic hydrogels were obtained. The immobilization of yeast cells with these copolymer carriers led to a higher ethanol productivity than free cells. Of all copolymer carriers, the ethanol yield with poly (HEA-14 G) was the highest, about 2.45 times as high as that of free yeast cells. In addition, the ethanol productivity of 12 batch repeated reactions with poly (HEA-14G) carrier was all higher than that of free yeast cells. The ethanol productivity of immobilized yeast cells was dependent on the proportion of hydrophilic monomer to other monomers in copolymer systems, the chain length of the bifunctional monomer, the degree of hydration of copolymer carriers, the structure of copolymer carriers and porosity in the internal structure of carriers. The ethanol yield of immobilized cells depended on swelling ability and porosity of copolymer carriers

  12. Impact of Quality Assurance Rounds in a Canadian Radiation Therapy Department

    Energy Technology Data Exchange (ETDEWEB)

    Lefresne, Shilo; Olivotto, Ivo A.; Joe, Howard; Blood, Paul A. [Radiotherapy Department, BC Cancer Agency, Vancouver Island Centre, Vancouver, British Columbia (Canada); Radiotherapy Department, University of British Columbia, Vancouver, British Columbia (Canada); Olson, Robert A., E-mail: rolson2@bccancer.bc.ca [Radiotherapy Department, University of British Columbia, Vancouver, British Columbia (Canada); Radiotherapy Department, BC Cancer Agency, Centre for the North, Prince George, British Columbia (Canada)

    2013-03-01

    Purpose: Quality assurance (QA) programs aim to identify inconsistencies that may compromise patient care. Radiation treatment planning is a well-documented source of variation in radiation oncology, leading many organizations to recommend the implementation of QA rounds in which radiation therapy plans are peer reviewed. This study evaluates the outcome of QA rounds that have been conducted by a radiation therapy department since 2004. Methods and Materials: Prospectively documented records of QA rounds, from 2004 to 2010, were obtained. During rounds, randomly selected radiation therapy plans were peer reviewed and assigned a grade of A (adequate), B (minor suggestions of change to a plan for a future patient), or C (significant change required before the next fraction). The proportion of plans that received each recommendation was calculated, and the relationship between recommendations for each plan, tumor site, and mean years of experience of the radiation oncologist (RO) were explored. Chart reviews were performed for each plan that received a C. Results: During the study period, 1247 plans were evaluated; 6% received a B and 1% received a C. The mean RO years of experience were lower for plans graded C versus those graded A (P=.02). The tumor sites with the highest proportion of plans graded B or C were gastrointestinal (14%), lung (13%), and lymphoma (8%). The most common reasons for plans to receive a grade of C were inadequate target volume coverage (36%), suboptimal dose or fractionation (27%), errors in patient setup (27%), and overtreatment of normal tissue (9%). Conclusions: This study demonstrated that QA rounds are feasible and an important element of a radiation therapy department's QA program. Through peer review, plans that deviate from a department's expected standard can be identified and corrected. Additional benefits include identifying patterns of practice that may contribute to inconsistencies in treatment planning and the

  13. Radiosensitization and radiation chemistry studies using CHO cells

    International Nuclear Information System (INIS)

    The cytotoxicity, radiosensitization and radiation chemistry studies on several recently synthesized isoindole-4,7-diones using chinese hamster ovary cells (CHO) have been carried out. The cytotoxicity studies have shown that these quinones have cytotoxic activity under oxic and hypoxic conditions. Radiosensitization studies using a Cs-137 irradiator at different radiation doses demonstrate that these isoindole-diones have radiosensitization characteristics under hypoxic conditions. The results are compared with the well known radiosensitizer, misoidazole, under the same conditions. The electron redox potential of these quinones are in the vicinity of -440mv to -360mv, which demonstrates that they have the appropriate electron affinity to transfer electrons quite readily. The interaction of glutathione, a well known radioprotector, with these quinones was also studied. The concentration of glutathione in CHO cells decreases very little in the presence of the isoindole-diones. The results of these experiments show that the radiosensitization mechanism of these isoindole-diones is mainly due to electron transfer reactions and not to interaction with chemical radioprotectors such as glutathione in the CHO cells

  14. Equivalent circuit analysis of radiative coupling in monolithic tandem solar cells

    International Nuclear Information System (INIS)

    As solar cell efficiency improves towards the Shockley-Queisser limit, so does the radiative efficiency of the cell. For tandem stacks of cells where energy conversion efficiency now exceeds 46%, radiative coupling between the cells is becoming increasingly important to consider in cell design, measurement, and performance prediction. We show how an equivalent circuit model can capture the complex radiative interactions between cells in such tandem stacks, allowing more insight into the impact on cell performance. The circuit's use is demonstrated by deriving results relevant to the critical step of eliminating coupling effects from measured cell spectral responses

  15. Radiation dose to patients and image quality evaluation from coronary 256-slice computed tomographic angiography

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Liang-Kuang [Department of Radiology, Shin Kong Wu Ho-Su Memorial Hospital, Taiwan (China); College of Medicine, Fu Jen Catholic University, Taiwan (China); Department of Radiological Technology, Yuan Pei University, Taiwan (China); Wu, Tung-Hsin [Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, 155 Li-Nong St., Section 2, Taipei 112, Taiwan (China); Yang, Ching-Ching [Department of Radiological Technology, Tzu Chi College of Technology, Hualien, Taiwan (China); Tsai, Chia-Jung [Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, 155 Li-Nong St., Section 2, Taipei 112, Taiwan (China); Lee, Jason J.S., E-mail: jslee@ym.edu.t [Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, 155 Li-Nong St., Section 2, Taipei 112, Taiwan (China)

    2010-07-21

    The aim of this study is to assess radiation dose and the corresponding image quality from suggested CT protocols which depends on different mean heart rate and high heart rate variability by using 256-slice CT. Fifty consecutive patients referred for a cardiac CT examination were included in this study. All coronary computed tomographic angiography (CCTA) examinations were performed on a 256-slice CT scanner with one of five different protocols: retrospective ECG-gating (RGH) with full dose exposure in all R-R intervals (protocol A), RGH of 30-80% pulsing window with tube current modulation (B), RGH of 78{+-}5% pulsing window with tube current modulation (C), prospective ECG-triggering (PGT) of 78% R-R interval with 5% padding window (D) and PGT of 78% R-R interval without padding window (E). Radiation dose parameters and image quality scoring were determined and compared. In this study, no significant differences were found in comparison on image quality of the five different protocols. Protocol A obtained the highest radiation dose comparing with those of protocols B, C, D and E by a factor of 1.6, 2.4, 2.5 and 4.3, respectively (p<0.001), which were ranged between 2.7 and 11.8 mSv. The PGT could significantly reduce radiation dose delivered to patients, as compared to the RGH. However, the use of PGT has limitations and is only good in assessing cases with lower mean heart rate and stable heart rate variability. With higher mean heart rate and high heart rate variability circumstances, the RGH within 30-80% of R-R interval pulsing window is suggested as a feasible technique for assessing diagnostic performance.

  16. Implementation of Remote 3-Dimensional Image Guided Radiation Therapy Quality Assurance for Radiation Therapy Oncology Group Clinical Trials

    International Nuclear Information System (INIS)

    Purpose: To report the process and initial experience of remote credentialing of three-dimensional (3D) image guided radiation therapy (IGRT) as part of the quality assurance (QA) of submitted data for Radiation Therapy Oncology Group (RTOG) clinical trials; and to identify major issues resulting from this process and analyze the review results on patient positioning shifts. Methods and Materials: Image guided radiation therapy datasets including in-room positioning CT scans and daily shifts applied were submitted through the Image Guided Therapy QA Center from institutions for the IGRT credentialing process, as required by various RTOG trials. A centralized virtual environment is established at the RTOG Core Laboratory, containing analysis tools and database infrastructure for remote review by the Physics Principal Investigators of each protocol. The appropriateness of IGRT technique and volumetric image registration accuracy were evaluated. Registration accuracy was verified by repeat registration with a third-party registration software system. With the accumulated review results, registration differences between those obtained by the Physics Principal Investigators and from the institutions were analyzed for different imaging sites, shift directions, and imaging modalities. Results: The remote review process was successfully carried out for 87 3D cases (out of 137 total cases, including 2-dimensional and 3D) during 2010. Frequent errors in submitted IGRT data and challenges in the review of image registration for some special cases were identified. Workarounds for these issues were developed. The average differences of registration results between reviewers and institutions ranged between 2 mm and 3 mm. Large discrepancies in the superior-inferior direction were found for megavoltage CT cases, owing to low spatial resolution in this direction for most megavoltage CT cases. Conclusion: This first experience indicated that remote review for 3D IGRT as part of QA

  17. Durability Quality Research of Concrete Containing Solar PV Cells

    Directory of Open Access Journals (Sweden)

    Chao Sao-Jeng

    2015-01-01

    Full Text Available In this article we demonstrated the study results of durability quality of concrete containing waste solar PV cells. The study used alkali activator to improve the activity of alkali-activated materials in solar PV cells so as to replace Portland cement as binder in concrete. By using sodium hydroxide as an alkali-activator, a high-pH environment is generated to excite the binding characteristics of alkali-activated materials in solar PV cells, and thus develops better durability of the mixes. The conclusions were made on effect of this cement replacement. As a result, we identified the durability for those of 16 concrete specimens predefined and made to consider various possible control factors. The conclusions also depicted that all experiments but the drying shrinkage may be helpful with the suitable use of control factors as far as concerning the recycled solar PV cells for mixing in concrete. In other words, the durability quality of concrete may be partially unacceptable of containing solar PV cells.

  18. Optimization of dose radiation and image quality on computed tomography of thorax in adult women

    International Nuclear Information System (INIS)

    Full text: The objective of the study is the optimization of the dose (Dlp) and image quality in the exploration of adult women in studies of thorax with computed tomography (CT). The CT is a technique of exploration with high radiation doses to patients with an increase of the risk factors of developing cancer in the future, but X-rays are a very important medical diagnostic tool. We performed a retrospective survey of 50 female patients who had thorax tomography using the automatic protocol established by the manufacturer, a database of dose (Dlp), measures of patient A P and radiological parameters such as kV and m A was obtained. Subsequently, we carry out the prospective study with 30 patients with prescription of thorax tomography, scans were conducted with CT with reduced doses using manual techniques protocol of exploration while maintaining diagnostic image quality. The results show that the prospective study patients received doses lower than 30% on average. In general the dose patients were within the confidence interval of 95% of the levels of diagnostic reference (DRL) adopted by the European Community for CT and the most common value is 400 Dlp for thorax. Comparative image quality study was conducted using the protocol of the manufacturer and the manual protocol and image quality was diagnostic after dose reduction up to 30%. The reduction of radiation dose in female patients in studies of thorax CT helps to reduce risk factors of developing cancer later in life. A thorax tomography study includes the fibro-glandular tissue of the breast which is very sensitive to stochastic effects of radiation. (Author)

  19. Optimization of dose radiation and image quality on computed tomography of thorax in adult women

    Energy Technology Data Exchange (ETDEWEB)

    Cruz Z, G. R.; Casian C, G. [Hospital Juarez de Mexico, Av. IPN No. 5160, 07760 Mexico D. F. (Mexico); Gaona, E.; Franco E, J. G.; Molina F, N., E-mail: gaen1310@correo.xoc.uam.mx [Universidad Autonoma Metropolitana, Unidad Xochimilco, Calz. del Hueso 1100, 04960 Mexico D. F. (Mexico)

    2015-10-15

    Full text: The objective of the study is the optimization of the dose (Dlp) and image quality in the exploration of adult women in studies of thorax with computed tomography (CT). The CT is a technique of exploration with high radiation doses to patients with an increase of the risk factors of developing cancer in the future, but X-rays are a very important medical diagnostic tool. We performed a retrospective survey of 50 female patients who had thorax tomography using the automatic protocol established by the manufacturer, a database of dose (Dlp), measures of patient A P and radiological parameters such as kV and m A was obtained. Subsequently, we carry out the prospective study with 30 patients with prescription of thorax tomography, scans were conducted with CT with reduced doses using manual techniques protocol of exploration while maintaining diagnostic image quality. The results show that the prospective study patients received doses lower than 30% on average. In general the dose patients were within the confidence interval of 95% of the levels of diagnostic reference (DRL) adopted by the European Community for CT and the most common value is 400 Dlp for thorax. Comparative image quality study was conducted using the protocol of the manufacturer and the manual protocol and image quality was diagnostic after dose reduction up to 30%. The reduction of radiation dose in female patients in studies of thorax CT helps to reduce risk factors of developing cancer later in life. A thorax tomography study includes the fibro-glandular tissue of the breast which is very sensitive to stochastic effects of radiation. (Author)

  20. Radiation-induced genetic effects in germ cells of mammals

    International Nuclear Information System (INIS)

    The aim of the project is a radiosensitivity investigation of the 'resting' oocytes, which represent some 90% of the total population of oocytes in the ovary and are the most important female germ cells from the genetic point of view, since they receive the largest part of the genetically significant lifetime dose of radiation. An evaluation of the radiosensitivity of the resting oocyte of the guinea-pig at its two different nuclear states is presented. This project concentrates on long-term reproductive effects and on cytogenetic effects. (R.P.) 1 ref

  1. Radiative recombination and photon recycling in gallium arsenide solar cells

    Science.gov (United States)

    Lundstrom, M. S.; Melloch, M. R.; Lush, G. B.; Patkar, M. P.; Young, M.; Durbin, S. M.; Gray, J. L.; MacMillan, H. F.; Keyes, B. M.; Levi, D. H.; Ahrenkiel, R. K.

    1992-12-01

    This talk reviews experimental work to develop a detailed understanding of radiative recombination in n-GaAs. Photoluminescence decay studies of minority carrier lifetimes versus doping in n-GaAs are presented. We show that when the substrate is removed by etching, photon recycling is enhanced, and lifetimes increase by nearly a factor of 10. The doping-dependent absorption coefficient is measured, and detailed balance arguments are used to relate absorption and recombination. Modeling surfaces, verified by comparison with experiments, are used to examine the effects of recycling in conventional solar cells and to explore new design options.

  2. Intervention of oxygen-control ability to radiation sensitivity, cell aging and cell transformation

    International Nuclear Information System (INIS)

    Oxygen is essential for life, and cells have therefore developed numerous adaptive responses to oxygen change. Here, we examined the difference in oxygen-control functions of human (HE), mouse (ME), and Syrian hamster embryo (SHE) cells cultured under different oxygen conditions (0.5%, 2% and 20%), and also examined whether oxygen tensions contributed to cellular lifespan and transformation. HE cells had their replicative lifespan slightly extended under hypoxic (0.5% and 2% oxygen) conditions, but were not immortalized under any of the oxygen concentrations. On the other hand, although ME cells cultured under 20% oxygen tension decreased their proliferation potency temporarily at early stage, all rodent cells were immortalized and acquired anchorage-independency, regardless of oxygen tension. These results suggest that cellular oxygen control function is related to sensitivities cellular immortalization and transformation. To understand intervention of oxygen control ability on cellular immortalization and transformation, we examined the intracellular oxidative level, mitochondria functions and radiation sensitivity. Intracellular oxidative levels of hypoxically cultured rodent cells were significantly enhanced. Mitochondrial membrane potential was altered depend on oxygen tensions, but the change was not parallel to mitochondria number in rodent cells. ME cells were particularly sensitive to oxygen change, and showed a clear oxygen effect on the X-ray survival. However, there was no difference in frequency of radiation-induced micronuclei between HE and ME cells. These results suggest that the response to oxygen change differs markedly in HE and rodent cells. (author)

  3. Radiation safety and quality control assurance in X-ray diagnostics 1998; Saeteilyturvallisuus ja laadunvarmistus roentgendiagnostiikassa 1998

    Energy Technology Data Exchange (ETDEWEB)

    Servomaa, A. [ed.

    1998-03-01

    The report is based on a seminar course of lectures `Radiation safety and quality assurance in X-ray diagnostics 1998` organized by the Radiation and Nuclear Safety Authority (STUK) in Finland. The lectures included actual information on X-ray examinations: methods of quality assurance, methods of measuring and calculating patient doses, examination frequencies, patient doses, occupational doses, and radiation risks. Paediatric X-ray examinations and interventional procedures were the most specific topics. The new Council Directive 97/43/Euratom on medical exposure, and the European Guidelines on quality criteria for diagnostic radiographic images, were discussed in several lectures. Lectures on general radiation threats and preparedness, examples of radiation accidents, and emergency preparedness in hospitals were also included. (editor)

  4. Stereotactic body radiation therapy versus conventional radiation therapy in patients with early stage non-small cell lung cancer

    DEFF Research Database (Denmark)

    Jeppesen, Stefan S; Schytte, Tine; Jensen, Henrik R;

    2013-01-01

    Abstract Introduction. Stereotactic body radiation therapy (SBRT) for early stage non-small cell lung cancer (NSCLC) is now an accepted and patient friendly treatment, but still controversy exists about its comparability to conventional radiation therapy (RT). The purpose of this single...... SBRT predicted improved prognosis. However, staging procedure, confirmation procedure of recurrence and technical improvements of radiation treatment is likely to influence outcomes. However, SBRT seems to be as efficient as conventional RT and is a more convenient treatment for the patients....

  5. Effects of ionizing radiation on bone cell differentiation in an experimental murine bone cell model

    Science.gov (United States)

    Baumstark-Khan, Christa; Lau, Patrick; Hellweg, Christine; Reitz, Guenther

    During long-term space travel astronauts are exposed to a complex mixture of different radiation types under conditions of dramatically reduced weight-bearing activity. It has been validated that astronauts loose a considerable amount of bone mass at a rate up to one to two percent each month in space. Therapeutic doses of ionizing radiation cause bone damage and increase fracture risks after treatment for head-and-neck cancer and in pelvic irradiation. For low radiation doses, the possibility of a disturbed healing potential of bone was described. Radiation induced damage has been discussed to inflict mainly on immature and healing bone. Little is known about radiation effects on bone remodelling and even less on the combined action of microgravity and radiation. Bone remodelling is a life-long process performed by balanced action of cells from the osteoblast and osteoclast lineages. While osteoblasts differentiate either into bone-lining cells or into osteocytes and play a crucial role in bone matrix synthesis, osteoclasts are responsible for bone resorption. We hypothesize that the balance between bone matrix assembly by osteocytes and bone degradation by osteoclasts is modulated by microgravity as well as by ionizing radiation. To address this, a cell model consisting of murine cell lines with the potential to differentiate into bone-forming osteoblasts (OCT-1, MC3T3-E1 S24, and MC3T3-E1 S4) was used for studying radiation response after exposure to simulated components of cosmic radiation. Cells were exposed to graded doses of 150 kV X-rays, α particles (0.525 MeV/u, 160 keV/µm; PTB, Braunschweig, Germany) and accelerated heavy ions (75 MeV/u carbon, 29 keV/µm; 95 MeV/u argon, 230 keV/µm; GANIL, Caen, France). Cell survival was measured as colony forming ability; cell cycle progression was analyzed via fluorescence-activated cell scanning (FACS) by measurement of the content of propidium iodide-stained DNA, DNA damage was visualized by γH2AX

  6. SU-E-T-581: On the Value of LET as a Radiation Quality Descriptor for RBE

    International Nuclear Information System (INIS)

    Purpose: To investigate the relationship between linear energy transfer (LET) and relative biological effectiveness (RBE) for protons and light ions, and the corresponding role of LET as a descriptor of radiation quality of hadron therapy. Methods: Monte Carlo (MC) proton and light ion (He, Li, C) tracks with LET < 30 eV nm-1 were generated in an event-by-event mode. They were overlaid on a cell nucleus model containing 6×109 nucleotide base pairs using an isotropic irradiation procedure that provides electronic equilibrium. Strand breaks (sbs) were scored in the DNA sugar-phosphate groups and further sub-classified into single or double sbs (ssbs or dsbs). Distributions of ssbs and dsbs for 2 Gy fractions were calculated to estimate RBE for the induction of initial dsbs with reference to 60Co. Additionally, sbs were classified based on their complexity (i.e. the number of sbs in each cluster). Results: An increase in LET for light ions of the same atomic number or a decrease in atomic number for ions of the same LET resulted in a lower kinetic energy of emitted secondary electrons. The clustering of DNA damage was more pronounced as reflected by the increase in proton RBE from ∼ 1.75 to 4 for LET values of 7 to 28 eV nm-1. A significant RBE decrease between protons, He, Li and C ions of the same LET was also noticed as function of the atomic number. Significant differences in ssbs and dsbs complexities were also seen for particles with the same LET, potentially supporting a clustering-based radiation quality descriptor. Conclusion: The LET-RBE relationships were simulated for proton and light ions and exhibited expected trends, including different RBEs for particles with the same LET but different atomic numbers. A complexity based radiation quality descriptor may allow better differentiation of RBE between radiation fields of similar LET. We would like to acknowledge support from the Fonds de recherche du Quebec Sante (FRQS), from the CREATE Medical Physics

  7. SU-E-T-581: On the Value of LET as a Radiation Quality Descriptor for RBE

    Energy Technology Data Exchange (ETDEWEB)

    Pater, P; Backstrom, G; Enger, S; Seuntjens, J; Naqa, I El [McGill University, Montreal, Quebec (Canada); Villegas, F; Ahnesjo, A [Uppsala University, Uppsala (Sweden)

    2015-06-15

    Purpose: To investigate the relationship between linear energy transfer (LET) and relative biological effectiveness (RBE) for protons and light ions, and the corresponding role of LET as a descriptor of radiation quality of hadron therapy. Methods: Monte Carlo (MC) proton and light ion (He, Li, C) tracks with LET < 30 eV nm{sup -1} were generated in an event-by-event mode. They were overlaid on a cell nucleus model containing 6×10{sup 9} nucleotide base pairs using an isotropic irradiation procedure that provides electronic equilibrium. Strand breaks (sbs) were scored in the DNA sugar-phosphate groups and further sub-classified into single or double sbs (ssbs or dsbs). Distributions of ssbs and dsbs for 2 Gy fractions were calculated to estimate RBE for the induction of initial dsbs with reference to {sup 60}Co. Additionally, sbs were classified based on their complexity (i.e. the number of sbs in each cluster). Results: An increase in LET for light ions of the same atomic number or a decrease in atomic number for ions of the same LET resulted in a lower kinetic energy of emitted secondary electrons. The clustering of DNA damage was more pronounced as reflected by the increase in proton RBE from ∼ 1.75 to 4 for LET values of 7 to 28 eV nm{sup -1}. A significant RBE decrease between protons, He, Li and C ions of the same LET was also noticed as function of the atomic number. Significant differences in ssbs and dsbs complexities were also seen for particles with the same LET, potentially supporting a clustering-based radiation quality descriptor. Conclusion: The LET-RBE relationships were simulated for proton and light ions and exhibited expected trends, including different RBEs for particles with the same LET but different atomic numbers. A complexity based radiation quality descriptor may allow better differentiation of RBE between radiation fields of similar LET. We would like to acknowledge support from the Fonds de recherche du Quebec Sante (FRQS), from the

  8. Quality assurance in personal dosimetry of external radiation: present situation and future needs

    International Nuclear Information System (INIS)

    Whole body personal dosimetry is well established for the individual monitoring of radiation workers. High quality radiation dosimetry is essential for workers who rely upon personal dosemeters to record the amount of radiation to which they are exposed. The mandate has been given to the Personal Dosimetry, (secondary standard dosimetry laboratories) S.S.D.L., (Malaysian institute for nuclear energy research) M.I.N.T. to assure the individual monitoring for radiation workers in Malaysia. In 2005, the S.S.D.L;-M.I.N.T. supply, process and read out of personal dosemeters of nearly 13,000 dosimeters monthly, whereby. 12,000 are films and 1,000 are T.L.D.s. The objective of individual monitoring is not limited to the measurement of doses delivered to individuals, but it should demonstrate that limits of exposure have not been exceeded and that working conditions have not unexpectedly deteriorated. Dosimetry measurements are an important component of radiation protection programs and must be of high quality. The exposure of workers to radiation must be controlled and monitored in order to comply with regulatory requirements. S.S.D.L.-M.I.N.T; demonstrates that its performance is at an acceptable level by implementing overall system performance, as evidenced by the ISO 9001 certification of the Personal Dosimetry Service in 2002 and ISO/I.E.C. 17025 accreditation to the calibration laboratory in 2004. The certification and accreditation processes achieved the goal by formalizing the recognition of satisfactory performance, and providing evidence of this performance. Overall performances are assessed, personnel operating the system will be trained and are well qualified and all actions will be documented. The paper describes the overview of the Q.M.S. carried out at the S.S. D.L.-M.I.N.T.. During the implementation of Q.M.S. a few areas has been identified for future consideration. These include performance specification and type testing of dosemeters, which provide a

  9. Studies on radiation transformation of cultured mammalian cells

    International Nuclear Information System (INIS)

    In an attempt to induce in vitro transformation by radiation, several cell lines and primary cultures derived from embryonal tissues of hamster, mouse and man were tested. Under various conditions favorable for transformation, none of these were successfully transformed except for C3H mouse embryo-derived 10Tl/2 cells. Normally the cells contact-inhibited were irradiated with single graded doses and dispersed 3 hours after, followed by inoculation and 8-week cultivation with repeated medium renewals. A few types of focus were identified according to the description of Reznikoff et al. The foci characterized by (i) high cell density, (ii) increased affinity to a basic dye, and (iii) piled-up structure, were taken as an indication of transformation. The frequency of transformation was 6.5 x 10-4 for 300 R which was 4 times higher than the frequency found in the untreated control. It increased dose-dependently until 500 R and then levelled off. Another type of experiment using TR cells derived from a leukemia-prone trisomy 21 human embryo, revealed that a single 300 R exposure to x-ray induced clones showing higher plating efficiency and plateau density than unirradiated control after 200 days of post-irradiation cultivation. However, the clones isolated did not show any particular transformational properties in vitro and tumorigenic activity on inoculation into nude mice. (author)

  10. Quality assurance for measurements of ionizing radiation. Annual report 15 Sep 80-30 Sep 81

    International Nuclear Information System (INIS)

    This report describes results of the first year of a program that will enable the Nuclear Regulatory Commission to improve, demonstrate, and document traceability of its measurements to the national physical measurement standards for ionizing radiation. The principal actions being taken are: (1) characterization of the response of thermoluminescence dosimetry systems used for routine surveillance of nuclear facilities; (2) type testing and characterization of portable survey instruments; and (3) implementation of routine quality assurance services which will demonstrate that regulatory measurements are sufficiently consistent (in agreement) with national measurement standards. During the year, some tests of the TLD system were performed as specified in American National Standard N545-1975, specifically uniformity, reproducibility, dependence of exposure interpretation on the length of the field cycle, energy dependence, light dependence, and moisture dependence. The energy dependence of five portable survey instruments was determined for exposure to photon radiation, and a chamber for exposure to gaseous sources of beta radiation was designed and partly built. The four laboratories which calibrate portable survey instruments for NRC inspectors were invited to participate in measurement quality assurance interactions with NBS, and all expressed a desire to do so

  11. Improved postharvest quality in patagonian squash (Cucurbita moschata) coated with radiation depolymerized chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Pugliese, Maria Alicia; Goitia, Maria Teresa [Laboratorio de Investigaciones Basicas Aplicadas en Quitina, Departamento de Quimica, Universidad Nacional del Sur. Avenida Alem 1253, B8000CPB Bahia Blanca (Argentina); Yossen, Mariana [Instituto de Desarrollo Tecnologico para la Industria Quimica (INTEC), CONICET-Universidad Nacional del Litoral, Ruta Nacional 168-Paraje ' El Pozo' , 3000 Santa Fe (Argentina); Cifone, Norma; Agullo, Enrique [Laboratorio de Investigaciones Basicas Aplicadas en Quitina, Departamento de Quimica, Universidad Nacional del Sur. Avenida Alem 1253, B8000CPB Bahia Blanca (Argentina); Andreucetti, Noemi, E-mail: andreuce@criba.edu.ar [Laboratorio de Radioisotopos, Departamento de Quimica, Universidad Nacional del Sur, Avenida Alem 1253, B8000CPB Bahia Blanca (Argentina)

    2011-12-15

    Different molecular weight chitosans were evaluated on the decay of coated Anquito squashes (Cucurbita moschata) as well as the maintenance of the fruit quality along five storage months. The original chitosan (Mw=391 kDa, 83% DD), was depolymerized by gamma radiation. Apart from chain scission, other chemical changes were not detected by FTIR or UV-vis analyses. The molecular weight characterization of chitosans was done by size exclusion chromatography with dual light scattering and concentration detection (SEC-MALLS-RI). The coating effectiveness was evaluated on the following parameters: fungal decay incidence, weight loss, firmness, total reducing sugar, soluble solid, flesh color, carotene content, pH and titratable acidity. No sign of fungal decay was observed in squashes coated with 122 and 56 kDa chitosans, which were also the most effective treatments in reducing the weight loss. The chitosan with Mw=122 kDa was also the best treatment considering firmness, internal aspect, sugar and carotene content. Then, radiation degraded chitosan was better in C. moschata preservation than the original chitosan. - Highlights: > Original Chitosan was radiation depolymerized producing chitosans with lower molecular weights. > Gamma-irradiated chitosans only exhibit chain scission. > SEC-MALLS-RI chromatography is a useful tool in molecular weight analysis. > Depolymerized chitosans were the best in maintaining the quality and the storage life of coated squashes.

  12. Response of hematopoietic stem cells to ionizing radiation; Reponse des cellules souches hematopoitiques aux radiations ionisantes

    Energy Technology Data Exchange (ETDEWEB)

    Simonnet, A

    2008-12-15

    Hematopoietic stem cells (HSCs) maintain blood and immune system throughout life and restore them after hematological injuries. Exposure of an organism to ionizing radiation (IR) causes rapid and acute myelosuppression and challenges the replenishment capacity of HSCs. Yet, the precise damages that are generated remain largely unexplored. To better understand these effects, phenotypic and functional changes in the stem/progenitor compartments of sublethally irradiated mice were monitored over a ten week period after radiation exposure. We report that shortly after sublethal IR-exposure, HSCs, defined by their repopulating ability, still segregate in the Hoechst dye excluding side population (SP); yet, their Sca-1 (S) and c-Kit (K) expression levels are increased and severely reduced, respectively, with a concurrent increase in the proportion of SP{sup SK} cells positive for established indicators of HSC presence: CD150{sup +} and CD105{sup +}. A great proportion of HSCs quickly but transiently enter the cell cycle to replenish the bone marrow of myelo-ablated mice. Ten weeks after, whereas bone marrow cellularity has recovered and hematopoietic homeostasis is restored, major phenotypic modifications can be observed within the Lin{sup -/low} Sca-1{sup +} c-Kit{sup +} (LSK) stem/progenitor compartment: CD150{sup +}/Flk2{sup -} and CD150{sup -}/Flk2{sup +} LSK cell frequencies are increased and dramatically reduced, respectively. CD150{sup +} LSK cells also show impaired reconstitution capacity, accrued number of {gamma}-H2AX foci and increased tendency to apoptosis. This demonstrates that the LSK compartment is not properly restored 10 weeks after sublethal exposure, and that long-term IR-induced injury to the bone marrow proceeds, at least partially, through direct damage to the stem cell pool. Thrombopoietin (TPO) has been shown to promote the survival of lethally irradiated mice when administrated quickly after exposure. We investigated the mechanisms underlying

  13. Response of hematopoietic stem cells to ionizing radiation

    International Nuclear Information System (INIS)

    Hematopoietic stem cells (HSCs) maintain blood and immune system throughout life and restore them after hematological injuries. Exposure of an organism to ionizing radiation (IR) causes rapid and acute myelosuppression and challenges the replenishment capacity of HSCs. Yet, the precise damages that are generated remain largely unexplored. To better understand these effects, phenotypic and functional changes in the stem/progenitor compartments of sublethally irradiated mice were monitored over a ten week period after radiation exposure. We report that shortly after sublethal IR-exposure, HSCs, defined by their repopulating ability, still segregate in the Hoechst dye excluding side population (SP); yet, their Sca-1 (S) and c-Kit (K) expression levels are increased and severely reduced, respectively, with a concurrent increase in the proportion of SPSK cells positive for established indicators of HSC presence: CD150+ and CD105+. A great proportion of HSCs quickly but transiently enter the cell cycle to replenish the bone marrow of myelo-ablated mice. Ten weeks after, whereas bone marrow cellularity has recovered and hematopoietic homeostasis is restored, major phenotypic modifications can be observed within the Lin-/low Sca-1+ c-Kit+ (LSK) stem/progenitor compartment: CD150+/Flk2- and CD150-/Flk2+ LSK cell frequencies are increased and dramatically reduced, respectively. CD150+ LSK cells also show impaired reconstitution capacity, accrued number of γ-H2AX foci and increased tendency to apoptosis. This demonstrates that the LSK compartment is not properly restored 10 weeks after sublethal exposure, and that long-term IR-induced injury to the bone marrow proceeds, at least partially, through direct damage to the stem cell pool. Thrombopoietin (TPO) has been shown to promote the survival of lethally irradiated mice when administrated quickly after exposure. We investigated the mechanisms underlying this effect, and found in a competitive transplant experiment that a

  14. Radiation transformation in differentiated human cells in culture

    International Nuclear Information System (INIS)

    A tissue culture technique is described for human thyroid tissue as an approach to studying mechanisms of human radiation carcinogenesis. Normal human tissue obtained from surgery is treated in one of two ways, depending upon size of specimen. Large pieces are completely digested in trypsin/ collagenase solution to a single cell suspension. Small pieces of tissue are plated as explants following partial digestion in trypsin/collagenase solution. Following irradiation of the primary differentiated monolayers (normally 10 days after plating), the development of transformed characteristics is monitored in the subsequent subcultures. A very high level of morphological and functional differentiation is apparent in the primary cultures. Over a period of approx. 6 months, the irradiated surviving cells continue to grow in culture, unlike the unirradiated controls which senesce after 2-3 subcultures. (UK)

  15. Role of radiation therapy in large cell lymphoma

    International Nuclear Information System (INIS)

    This paper compares the results of treatment for large cell lymphoma with use of radiation therapy (RT), chemotherapy (CT), or both. The authors retrospectively studied 142 patients with large cell lymphoma. Seventy-two has stage I or II disease and 70, stage III or IV; 37% had B symptoms. CT was used in 66 patients, RT in 22, both in 46, and surgery with or without RT or CT in eight. CT regimens were CHOP, 38 patients; C-MOPP/COPP, 25; CHOP-bleo/BACOP, 15; COP-BLAN-MEL, 8; M-BACOD, 8; COP/CVP, 5; COP-BLAM, 5; and other regimens, 12. Statistical analysis showed that age, stage B symptoms, and treatment were significant variables determining survival. In stages I and II, the 5-year survival rate with RT plus CT was 65%; with CT, 35%; and with RT, 9% (P = < .01)

  16. Noncultured Autologous Adipose-Derived Stem Cells Therapy for Chronic Radiation Injury

    Directory of Open Access Journals (Sweden)

    Sadanori Akita

    2010-01-01

    Full Text Available Increasing concern on chronic radiation injuries should be treated properly for life-saving improvement of wound management and quality of life. Recently, regenerative surgical modalities should be attempted with the use of noncultured autologous adipose-derived stem cells (ADSCs with temporal artificial dermis impregnated and sprayed with local angiogenic factor such as basic fibroblast growth factor, and secondary reconstruction can be a candidate for demarcation and saving the donor morbidity. Autologous adipose-derived stem cells, together with angiogenic and mitogenic factor of basic fibroblast growth factor and an artificial dermis, were applied over the excised irradiated skin defect and tested for Patients who were uneventfully healed with minimal donor-site morbidity, which lasts more than 1.5 years.

  17. Hygienic Quality Improvement of Fermented Fish (Pla-som) by Gamma Radiation

    International Nuclear Information System (INIS)

    Full text: Thirty-two samples of fermented fish (Pla-som) from commercial producers were evaluated for microbiological and chemical qualities. It was found that two samples (6.25%) did not meet the Thai Community Product Standard of Pla-som (TCPS.26/2548) because of the high level of Escherichia coli contamination. In addition, the chemical quality, namely p H, could meet the TCPS.26/2548. The effects of gamma radiation at the doses of 2, 4, 6, 8 and 10 kGy on microbiological and chemical qualities of Pla-som were also evaluated. Irradiation at 8 kGy could reduce the total viable bacterial count by 6-8 log cycles when compared to non-irradiated Pla-som. In addition, the results indicated that irradiation at 4 and 2 kGy effectively eliminated coliform bacteria and E. coli, respectively. The p H of irradiated Pla-som, p H did not change significantly when compared to non-irradiated Pla-som (p>0.05). From this study, it can be concluded that the irradiation dose at 8 kGy appeared to be sufficient for improving the microbiological quality of Pla-som. The irradiated Pla-som could be kept for 6 days at ambient temperature or 49 days at 5oC without significant differences on the sensory qualities when compared to non-irradiated Pla-som (p>0.05)

  18. Impact of Gamma Radiation Processing to Improve the Hygienic Quality of some Chicken Products

    International Nuclear Information System (INIS)

    For food to be entirely safe from the microbiological viewpoint, it must need to contain the least possible counts of microorganisms of hygienic importance. This investigation aims to study the possible use of gamma radiation for bacterial decontamination of chicken products which are produced in Egypt. One hundred and twenty samples of frozen chicken kofta and burgers (60 each) were purchased from retail markets at Cairo Governorate. They were surveyed for the hygienic quality as well as the effect of gamma radiation (dose levels of 1, 2 and 3 kGy) on the bacterial population, chemical and sensory quality of these products. The results indicated that the total aerobic bacterial counts (APC) ranged from 106 to 107 cfu/g in the examined samples. Moreover, some samples were contaminated with food borne pathogens such as Listeria species and Salmonella species. Gamma irradiation greatly reduced the microbial density of the studied food samples. The microbial reduction increased as the dose level of irradiation increase, whereas irradiation of chicken products at 3 kGy dose reduced aerobic counts and eliminated Salmonella and Listeria species, also it proved to be of great importance in increasing the safety and acceptability of ready to eat frozen chicken products with no adverse effect on their chemical or sensory quality

  19. X-ray spectra determination applied to establishment of radiation primary qualities at mammography

    International Nuclear Information System (INIS)

    An accurate determination of X-ray spectra is essential for studying the image quality and the absorbed dose in mammography. X-ray spectroscopy is usually performed using semiconductor detectors and a proper stripping procedure. In this work, an Si(Li) detector was used to measure mammographic x-ray spectra produces by a metrological tube with Molybdenum (Mo) target, operating at constant tube potentials between 22 and 35 kV. At the tube exit were inserted filters of Mo and/or Al with 99.9% of purity, in order to reproduce the radiation qualities produced by X-ray mammographic equipment. The detector response functions used in the stripping procedure were determined using a Monte Carlo method and validated through comparisons with experimental results obtained for radioactive sources (55Fe, 137Cs, 137Ba and 241Am). The results of this work show that a Si(Li) detector exhibits good response function in low energy. The measured X-ray spectra corrected using the stripping procedure, showed a good agreement with the reference clinical spectra. Besides, from the HVL values achieved in this work, it can conclude that the radiation qualities implemented in this work are consistent with that obtained for clinical X-ray beams and can be applied to calibration of the diagnostic radiology measurements instruments (e.g. ionization chambers. (author)

  20. Radiation dose and image quality for paediatric interventional cardiology systems. A national survey in Chile

    International Nuclear Information System (INIS)

    Radiation dose and image quality for paediatric protocols in all five X-ray fluoroscopy systems used for interventional cardiology procedures existing in Chile have been evaluated. Entrance surface air kerma (ESAK) and image quality using a test object (TO) and polymethyl methacrylate (PMMA) phantoms have been measured for the typical paediatric patient thicknesses (4-16 cm of PMMA). Images from fluoroscopy (low (FL), medium and high) and cine (CI) modes have been archived in DICOM format. Signal-to-noise ratio (SNR), figure of merit (FOM) and high-contrast spatial resolution (HCSR) have been computed from the images. The ratio between the maximum and the minimum value of ESAK per frame for a given fluoroscopy mode between the five systems ranges from 2 to 5 and from 14 to 38 for CI mode. SNR, FOM and HCSR showed a great variability for the different acquisition modes (AMs) and PMMA thickness. In the near future, it is urgent to upgrade Chilean legislation on radiation protection to incorporate quality assurance programmes that will allow us to evaluate and optimise the X-ray systems used in medical applications. Increments in doses per frame when increasing phantom thickness and when used CI runs instead of FL runs can be considered by the cardiologist in the good management of patient dose and allow them to select the best imaging AM during clinical procedures. (authors)

  1. Quality Control Quantification (QCQ): A Tool to Measure the Value of Quality Control Checks in Radiation Oncology

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Eric C., E-mail: eford@uw.edu [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland (United States); Terezakis, Stephanie; Souranis, Annette; Harris, Kendra [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland (United States); Gay, Hiram; Mutic, Sasa [Department of Radiation Oncology, Washington University, St. Louis, Missouri (United States)

    2012-11-01

    Purpose: To quantify the error-detection effectiveness of commonly used quality control (QC) measures. Methods: We analyzed incidents from 2007-2010 logged into a voluntary in-house, electronic incident learning systems at 2 academic radiation oncology clinics. None of the incidents resulted in patient harm. Each incident was graded for potential severity using the French Nuclear Safety Authority scoring scale; high potential severity incidents (score >3) were considered, along with a subset of 30 randomly chosen low severity incidents. Each report was evaluated to identify which of 15 common QC checks could have detected it. The effectiveness was calculated, defined as the percentage of incidents that each QC measure could detect, both for individual QC checks and for combinations of checks. Results: In total, 4407 incidents were reported, 292 of which had high-potential severity. High- and low-severity incidents were detectable by 4.0 {+-} 2.3 (mean {+-} SD) and 2.6 {+-} 1.4 QC checks, respectively (P<.001). All individual checks were less than 50% sensitive with the exception of pretreatment plan review by a physicist (63%). An effectiveness of 97% was achieved with 7 checks used in combination and was not further improved with more checks. The combination of checks with the highest effectiveness includes physics plan review, physician plan review, Electronic Portal Imaging Device-based in vivo portal dosimetry, radiation therapist timeout, weekly physics chart check, the use of checklists, port films, and source-to-skin distance checks. Some commonly used QC checks such as pretreatment intensity modulated radiation therapy QA do not substantially add to the ability to detect errors in these data. Conclusions: The effectiveness of QC measures in radiation oncology depends sensitively on which checks are used and in which combinations. A small percentage of errors cannot be detected by any of the standard formal QC checks currently in broad use, suggesting that

  2. Quality Control Quantification (QCQ): A Tool to Measure the Value of Quality Control Checks in Radiation Oncology

    International Nuclear Information System (INIS)

    Purpose: To quantify the error-detection effectiveness of commonly used quality control (QC) measures. Methods: We analyzed incidents from 2007-2010 logged into a voluntary in-house, electronic incident learning systems at 2 academic radiation oncology clinics. None of the incidents resulted in patient harm. Each incident was graded for potential severity using the French Nuclear Safety Authority scoring scale; high potential severity incidents (score >3) were considered, along with a subset of 30 randomly chosen low severity incidents. Each report was evaluated to identify which of 15 common QC checks could have detected it. The effectiveness was calculated, defined as the percentage of incidents that each QC measure could detect, both for individual QC checks and for combinations of checks. Results: In total, 4407 incidents were reported, 292 of which had high-potential severity. High- and low-severity incidents were detectable by 4.0 ± 2.3 (mean ± SD) and 2.6 ± 1.4 QC checks, respectively (P<.001). All individual checks were less than 50% sensitive with the exception of pretreatment plan review by a physicist (63%). An effectiveness of 97% was achieved with 7 checks used in combination and was not further improved with more checks. The combination of checks with the highest effectiveness includes physics plan review, physician plan review, Electronic Portal Imaging Device-based in vivo portal dosimetry, radiation therapist timeout, weekly physics chart check, the use of checklists, port films, and source-to-skin distance checks. Some commonly used QC checks such as pretreatment intensity modulated radiation therapy QA do not substantially add to the ability to detect errors in these data. Conclusions: The effectiveness of QC measures in radiation oncology depends sensitively on which checks are used and in which combinations. A small percentage of errors cannot be detected by any of the standard formal QC checks currently in broad use, suggesting that further

  3. Enhancement of radiation response in human cancer cells in vitro and in vivo by phytosphingosine

    International Nuclear Information System (INIS)

    Recent discoveries have revealed that sphingolipids (ceramide, sphingosine, sphingosine 1-phosphate, etc.) are highly bioactive compounds and are involved in diverse cell processes, including cell-cell interaction, cell proliferation, differentiation and apoptosis. However, the physiological roles of phytosphingosine are largely unknown. In the present study, we have investigated effect of phytosphingosine on anti-tumor activities of radiation in human cervical, breast, lung cancer cells and T cell lymphoma. Cells were treated with various concentrations of phytosphingosine and/or various doses of radiation. Phytosongosine sensitized cells in vitro and in vivo for treatment with ionizing radiation. Phytosphingosine in combination with ionizing radiation synergistically decreased clonogenic survival in a dose dependent manner. Similar to the result of clonogenic survival, in human cancer cells, combined treatment with phytosphingosine and ionizing radiation drastically induced apoptotic cell death. At dose levels of phytosphingosine with only minimal apoptotic effect, pretreatment of phytosphingosine synergistically enhanced ionizing radiation-induced apoptosis. Combined treatment with phytosphingosine and ionizing radiation resulted in an increased caspase family activation. In vivo, treatment of phytosphingosine (3 x 20 mg/kg) in combination with ionizing radiation exerted substantial tumor growth regression for human lung and cervical tumor xenograft. These results indicate that phytosphingosine can synergistically enhance radiosensitivity of human cancer cells in vitro and in vivo, suggesting a potential clinical application of combination treatment with phytosphingosine and ionizing radiation

  4. MarCell trademark software for modeling bone marrow radiation cell kinetics

    International Nuclear Information System (INIS)

    Differential equations were used to model cellular injury, repair, and compensatory proliferation in the irradiated bone marrow. Recently, that model was implemented as MarCell trademark, a user-friendly MS-DOS computer program that allows users from a variety of technical disciplines to evaluate complex radiation exposure. The software allows menu selections for different sources of ionizing radiation. Choices for cell lineages include progenitor, stroma, and malignant, and the available species include mouse, rat, dog, sheep, swine, burro, and man. An attractive feature is that any protracted irradiation can be compared with an equivalent prompt dose (EPD) in terms of cell kinetics for either the source used or for a reference such as 250 kVp x rays or 60Co. EPD is used to mean a dose rate for which no meaningful biological recovery occurs during the period of irradiation. For human as species, output from MarCell trademark includes: risk of 30-day mortality; risk of whole-body cancer and leukemia based either on radiation-induced cytopenia or compensatory cell proliferation; cell survival and repopulation plots as functions of time or dose; and 4-week recovery following treatment. copyright 1997 American Association of Physicists in Medicine

  5. Microdosimetric measurements of radiation quality variations in homogeneous phantoms irradiated by fast neutron beams

    International Nuclear Information System (INIS)

    The Dual Radiation Action Theory of Kellerer and Rossi (DRA), along with presently available microdosimetric techniques, is applied to the detrmination of radiation quality variation within tissue equivalent phantoms irradiated by collimated fast neutron beams. The neutron beams investigated were produced by the bombardment of 22.5 and 16 MeV d+ on beryllium and by the T(d,n)4He reaction (15-MeV neutrons). Microdosimetric spectra were obtained at points of varying depth and lateral distance from the central axis within a tissue equivalent phantom, including points within the penumbra. From the microdosimetric spectra the parameter RQ, a first approximation to RBE derived from DRA theory, is calculated for each point. All RQ values are calculated for the same level of effect. For these three different beams the results show that the RQ values for the total radiation spectrum of neutron and gamma radiation remain fairly constant with depth and with lateral distance from the beam axis at 2 and 10 cm depths. The largest central axis variation in RQ is 8% for the d(16)+Be beam. The largest variation between a penumbra and an on-axis RQ value is 4% at 2 cm depth in the d(22.5)+Be beam. The results for the d(22.5)+Be beam disagree with previously reported radiobiological results while the 15 MeV beam results are in good agreement

  6. Microdosimetric measurements of radiation quality variations in homogeneous phantoms irradiated by fast neutron beams

    International Nuclear Information System (INIS)

    The Dual Radiation Action Theory of Kellerer and Rossi (DRA), along with presently available microdosimetric techniques, is applied to the determination of radiation quality variation within tissue equivalent phantoms irradiated by collimated fast neutron beams. The neutron beams investigated were produced by the bombardment of 22.5 and 16 MeV d + on beryllium and by the T(d,n)4He reaction (15-MeV neutrons). Microdosimetric spectra were obtained at points of varying depth and lateral distance from the central axis within a tissue equivalent phantom, including points within the penumbra. From the microdosimetric spectra the parameter RQ, a first approximation to RBE derived from DRA theory, is calculated for each point. All RQ values are calculated for the same level of effect. For these three different beams the results show that the RQ values for the total radiation spectrum of neutron and gamma radiation remain fairly constant with depth and with lateral distance from the beam axis at 2 and 10 cm depths. The largest central axis variation in RQ is 8% for the d(16) + Be beam. The largest variation between a penumbra and an on-axis RQ value is 4% at 2 cm depth in the d(22.5) + Be beam. The results for the d (22.5) + Be beam disagree with previously reported radiological results while the 15 McV beam results are in good agreement

  7. Radiation Dose and Image Quality from Coronary Angiography in 320-Detecor Row CT

    International Nuclear Information System (INIS)

    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 HR75 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)

  8. Surviving protein quality control catastrophes--from cells to organisms.

    Science.gov (United States)

    Schneider, Kim; Bertolotti, Anne

    2015-11-01

    Organisms have evolved mechanisms to cope with and adapt to unexpected challenges and harsh conditions. Unfolded or misfolded proteins represent a threat for cells and organisms, and the deposition of misfolded proteins is a defining feature of many age-related human diseases, including the increasingly prevalent neurodegenerative diseases. These protein misfolding diseases are devastating and currently cannot be cured, but are hopefully not incurable. In fact, the aggregation-prone and potentially harmful proteins at the origins of protein misfolding diseases are expressed throughout life, whereas the diseases are late onset. This reveals that cells and organisms are normally resilient to disease-causing proteins and survive the threat of misfolded proteins up to a point. This Commentary will outline the limits of the cellular resilience to protein misfolding, and discuss the possibility of pushing these limits to help cells and organisms to survive the threat of misfolding proteins and to avoid protein quality control catastrophes. PMID:26483388

  9. Impact of radiation treatment on chemical, biochemical and sensory properties, and microbiological quality of mackerel

    Science.gov (United States)

    Pinter, Nino; Maltar-Strmečki, Nadica; Kozačinski, Lidija; Njari, Bela; Cvrtila Fleck, Željka

    2015-12-01

    The effect of gamma radiation on shelf-life of mackerel (Scomber scombrus) was studied. Changes in raw fish stored at 4 °C were investigated simultaneously, by performing sensory evaluation, chemical analysis (pH value and NH3 concentration), and biochemical analyses of histamine concentration and microbiological quality. Analyses showed that preservation by gamma irradiation prolonged the freshness and sustainability without any unintended sensory changes. Furthermore, increasing the dose during the 10 days of storage considerably reduced the concentration of histamine, but only slightly reduced the concentration of ammonia (NH3). Bacterial examinations showed that gamma radiation decreased the total number of bacteria. Our results indicated that the shelf-life of mackerel stored at 4 °C can be prolonged by irradiation with a dose of 3 kGy.

  10. Virtual monochromatic imaging in dual-source dual-energy CT: Radiation dose and image quality

    International Nuclear Information System (INIS)

    Purpose: To evaluate the image quality of virtual monochromatic images synthesized from dual-source dual-energy computed tomography (CT) in comparison with conventional polychromatic single-energy CT for the same radiation dose. Methods: In dual-energy CT, besides the material-specific information, one may also synthesize monochromatic images at different energies, which can be used for routine diagnosis similar to conventional polychromatic single-energy images. In this work, the authors assessed whether virtual monochromatic images generated from dual-source CT scanners had an image quality similar to that of polychromatic single-energy images for the same radiation dose. First, the authors provided a theoretical analysis of the optimal monochromatic energy for either the minimum noise level or the highest iodine contrast to noise ratio (CNR) for a given patient size and dose partitioning between the low- and high-energy scans. Second, the authors performed an experimental study on a dual-source CT scanner to evaluate the noise and iodine CNR in monochromatic images. A thoracic phantom with three sizes of attenuating rings was used to represent four adult sizes. For each phantom size, three dose partitionings between the low-energy (80 kV) and the high-energy (140 kV) scans were used in the dual-energy scan. Monochromatic images at eight energies (40 to 110 keV) were generated for each scan. Phantoms were also scanned at each of the four polychromatic single energy (80, 100, 120, and 140 kV) with the same radiation dose. Results: The optimal virtual monochromatic energy depends on several factors: phantom size, partitioning of the radiation dose between low- and high-energy scans, and the image quality metrics to be optimized. With the increase of phantom size, the optimal monochromatic energy increased. With the increased percentage of radiation dose on the low energy scan, the optimal monochromatic energy decreased. When maximizing the iodine CNR in

  11. Effects of Electromagnetic Radiation from Smartphones on Learning Ability and Hippocampal Progenitor Cell Proliferation in Mice

    OpenAIRE

    Choi, Yu-Jin; Choi, Yun-Sik

    2015-01-01

    Objectives Nonionizing radiation is emitted from electronic devices, such as smartphones. In this study, we intended to elucidate the effect of electromagnetic radiation from smartphones on spatial working memory and progenitor cell proliferation in the hippocampus. Methods Both male and female mice were randomly separated into two groups (radiated and control) and the radiated group was exposed to electromagnetic radiation for 9 weeks and 11 weeks for male and female mice, respectively. Spat...

  12. Radiation-induced cancer from low doses of ionizing radiation: risk analysis using the cell dose concept

    International Nuclear Information System (INIS)

    High doses of ionizing radiations are known to bear the risk of cancer to the exposed individual. In order to appreciate potential carcinogenesis from low doses also, the action of ionizing radiation in the human body has to be considered in holistic approach: energy depositions to individual cells trigger effects within a hierachical structure of interacting levels of biological systems, consisting consecutively of atoms, molecules, cells and organ tissue. The present paper describes the cell dose concept which is an essential factor in assessing the risk due to the ionizing radiation to the cells and tissues. Low dose of ionizing radiation induces adaptive response in individual cells which could be linked to the action of molecular radicals. Enzyme activities in bone marrow cells and bilayer lipid membranes and radicals are directly related to radiation effects. Temporary improvements of the detoxification of molecular radicals also improve the cellular defence. The risk analysis calls for more attention as it is important for radiation protection and other beneficial effects due to low doses of irradiation. (author). 18 refs

  13. Full-field digital mammography versus computed radiology mammography: comparison in image quality and radiation dose

    International Nuclear Information System (INIS)

    Objective: To investigate the differences in image quality and radiation dose between full- field digital mammography (FFDM) system and compute radiology mammography (CRM) system. Methods: The ALVIM mammographic phantom was exposed by FFDM system with automatic exposure control (AEC) and then exposed by CRM system with the unique imaging plank on the same condition. The FFDM system applied the same kV value and the different mAs values (14, 16, 18, 22 and 24 mAs), and the emission skin dose (ESD) and the average gland dose (AGD) were recorded for the above-mentioned exposure factors. All images were read by five experienced radiologists under the same condition and judged based on 5-point scales. And then receive operating characteristic (ROC) curve was drawn and the probability (Pdet) values were calculated. The data were statistically processed with ANOVA. Results: The Pdet values of calcifications and lesion lump were higher with FFDM system than with CRM system at the same dose (1.36 mGy). Especially, for microcalcifications and lesion lump, the largest difference of the Pdet value was 0.215, and that of lesion lump was 0.245. In comparison with CRM system, the radiation dose of FFDM system could be reduced at the same Pdet value. The ESD value was reduced by 26%, and the ACD value was reduced by 41%. When the mAs value exceed AEC value, the Pdet value almost had no change, though the radiation dose was increased. Conclusions: The detection rates of microcalcifications and lesion lump with FFDM system are proven to be superior to CRM system at the same dose. The radiation dose of FFDM system was less than CRM system for the same image quality. (authors)

  14. Structural inhomogeneity in mammography quality control phantoms detected by refraction-enhanced synchrotron radiation imaging

    International Nuclear Information System (INIS)

    Synchrotron radiation imaging with the refraction-enhancement mode visualized structural inhomogeneities in phantoms used for image quality control of mammography. Eight phantoms were examined, all of which were manufactured in the United States and approved by the American College of Radiology as dedicated phantoms. In addition to fiber- and mass-mimicking test objects, each phantom has 5 groups of calcification specks of various sizes. Synchrotron radiation (SR) imaging was performed at SPring-8, a synchrotron radiation facility in Japan. Images were obtained with monochromatic 20-keV x-ray beams, a radiation field of 15 mm x 26 mm at a sample plane, a charge-coupled device (CCD) camera with a resolution of 6 micrometers as a detector, and a sample-to-detector distance of 10 to 11 m. Two hundred and forty specks were evaluated in total in the SR images, and the surrounding area of each speck was also included. Evaluation of the images showed that 14 crack-like structures were depicted near specks, and there were 62 specks with attached void(s) or air bubble(s). Refraction-enhanced SR imaging sensitively detected structural inhomogeneities and abnormalities in phantoms which were implicitly agreed to have a homogeneous matrix and test objects without foreign substances. A possible manufacturing-dependent quality issue was identified. The effect of inhomogeneities detected by SR imaging on visual scoring of specks could not be identified in the tested phantoms; this should be assessed on images of other phantoms in a future study. (author)

  15. Influence of different anode/filter combination on radiation dose and image quality in digital mammography

    International Nuclear Information System (INIS)

    Objective: To explore the effect of different anode/filter combination on radiation dose and image quality in digital mammography, so as to choose optimal anode/filter combination to reduce radiation injury without scarifying image quality. Methods: Mammography accredition phantoms with the thickness from 1.6 cm to 8.6 cm were used to simulate human breast tissue. The same exposure conditions, pressure, compression thickness. and different anode/filter combination were employed under the automatic and manual exposure modes. The image kV, mAs, pressure, filter, average glandular dose (ACD), contrast to noise ratio (CNR) were recorded and the figure of merit (FOM) was calculated. SPSS 17.0 and one-way analysis of variance were used in the statistical analysis. Results: As the phantom thickness increase, the ACD values which were acquired with Mo/Mo, Mo/Rh, and W/Ag three different anode/filter combinations were increased, but CNR and FOM values were decreased, ACD, CNR, and FOM values which were acquired in the phantom with different thickness, and three different anode/filter combinations were statistically different (P=0.000, respectively). The ACD values of Mo/Mo were lowest. For 1.6 cm-2.6 cm phantom thicknesses, the FOMs of Mo/Rh were lowest, and for 3.6 cm-8.6 cm phantom thicknesses, the FOMs of W/Ag were lowest. Conclusion: Phantom thickness in 1.6 cm-2.6 cm and 3.6 cm-8.6 cm. Mo/Rh combination and W/Ag combination respectively can achieve the highest FOM, and can provide the best imaging quality with low radiation dose. (authors)

  16. Research of the application of matriXX system in radiation therapy quality control

    International Nuclear Information System (INIS)

    Objective: To investigate the accuracy, reliability and convenience of 2-D ionization chamber array MatriXX system in daily quality control of radiation therapy. Methods: The percent depth dose (PDD), tissue maximum ratio (TMR), off-axis ratio profile, penumbra and field width of Varian 23EX linac were measured by MatriXX system combined with solid water phantom and compared with the data acquired by RFA300 three-dimensional water phantom. The dose distributions of static and dynamic intensity modulated radiation therapy (IMRT) plans created by Pinnac3 V8.0 m three-dimensional treatment planning system (3D-TPS) were validated by MatriXX combined with the dose phantom made in home. Results: The PDD and TMR of 6MV X-ray measured by MatriXX system were parallel to the curves acquired by RFA300, and the PDD curve of 15MV X-ray measured by MatriXX was nearly identic to that measured by RFA300. The values of penumbra measured by MatriXX were two or three times larger than those measured by RFA300, and when the field size was smaller than 3 cm x 3 cm the penumbra of it could not be automatically calculated out by the MatriXX system. The characteristic information of field, such as symmetry and flatness and field width, can be acquired at once in a single sampling, which can be completed in less than 20 mS. The qualitative and quantificational verification of 2-D dose distribution of IMRT plans can be quickly implemented by using MatriXX system. Conclusions: The MatriXX system is very accurate and convenient and effective in quality control of clinical radiotherapy, and it's a perfect tool for the quality control procedure of radiation therapy. (authors)

  17. Radiation safety management in health care - The application of Quality Function Deployment

    International Nuclear Information System (INIS)

    The paper presents a study of the potential for applying the Quality Function Deployment (QFD) method to the analysis of the framework for safety management contained in the Ionising Radiation (Medical Exposure) Regulations (IRMER) of 2000. The QFD method has been successfully applied to many industrial and manufacturing processes in order to ensure that quality is built into products at the outset rather than tested for after their production. In this context, the term quality is used to describe the degree to which the needs and requirements of the customer are fulfilled. More frequently, now, the QFD approach is being applied to health care in order to engineer clinical processes that can best fulfil the needs of the patient. In the case of diagnostic radiology, safety management must not only be concerned with radiation protection but, more importantly, with the accuracy and consistency of any diagnostic outcome. Both are important patient needs. A first stage analysis of IRMER 2000 is presented that assesses how patients' needs are expressed by the individual IRMER components of justification, optimisation, clinical audit, expert advice, equipment and training. The analysis involved a QFD assessment by four radiation protection experts with over 100 man-years of experience. A second stage analysis assesses how the individual IRMER components have been engineered into a safety management framework through specific requirements embodied in IRMER 2000. The results of this assessment are discussed in terms of clinical, human, operational management and equipment related aspects of the radiological process. This study highlights how the QFD approach may be applied to engineer specific aspects of radiological practice that play a key role in ensuring that patients' needs are fully met. As an example, clinical audit requirements are analysed by means of the QFD method to indicate the design requirements of information and knowledge based systems that can provide the

  18. Models relevant to radiation effects on stem cell pools

    International Nuclear Information System (INIS)

    The available evidence clearly indicates the existence of a pluripotential primitive stem cell population (CFU). In the normal animal a large proportion of this population will 'sit' in the G0 state. At any time a small proportion of these cells will differentiate into one or more 'precursor' populations. One such precursor population is the erythropoietin responsive cell (ERC) and it is important to realize that this population has a significant number of mitoses in it, i.e. it is capable of considerable, although not indefinite proliferation. This is indicated by the colony growth during which, from a single colony former, large numbers of differentiated cells can be formed, in excess of several millions, at a time when the CFU numbers in the colony are still very small. To understand then the effects of radiation on this complex series of populations the following will have to be borne in mind. The ultimate stem cells are, at least in the small rodent, the CFU. It is their quantity that is essential for regeneration. However, the normal rate of differentiation of CFU in the small rodent is very low. This is because this rate of differentiation gives rise to a possibly committed precursor cell population such as the ERC, or possibly the agar forming 'GRC', the precursor populations with considerable proliferative potential in them. Therefore, after relatively small doses of radiation, or even during a regime of continuous irradiation, the proliferative potential of these transit precursor populations will be able to cope with near normal haemopoiesis at a time when the number of colony formers is gradually depleted. It is also significant that the rate of seeding of the primitive colony former is not related to its numbers and, therefore, under conditions of partial irradiation, at least in the small rodent, greatly increased relative migration and to some extent increased absolute migration of the CFU is possible, with consequent enhancement of the regeneration

  19. International conference on quality assurance and new techniques in radiation medicine. Book of extended synopses

    International Nuclear Information System (INIS)

    During the last decade, technological innovations have been introduced into medical practice to support new diagnostic and treatment modalities that involve the use of radiation. These innovations frequently depend on advanced, high-speed computer systems that operate with digitally processed information right up to the analogue display presented to the decision maker. The safety and effectiveness of the diagnosis and treatment provided to patients demand multidisciplinary teams of health care professionals to develop and monitor the equipment and confirm the integrity of its output. Quality control (QC) of individual components is used to ensure these new devices are functioning properly at each step in the chain. Nevertheless, a comprehensive quality assurance (QA) system is required to guarantee to patients that these medical procedures will yield valuable information or provide needed treatment that can be implemented properly and used to achieve a positive impact on their health. This conference focused on the QC tests and QA systems used in radiation medicine, particularly for new and emerging technologies. The conference provided a unique opportunity to deal with QA within several disciplines: In radiation oncology, a systematic approach is being developed to examine the impact of introducing new technologies in terms of treatment outcomes. The evidence will be based on assessing improved quality of life due to fewer complications and increased longevity due to better local control of disease. In nuclear medicine, QA objectives are the improvement of the quality and reproducibility of diagnostic imaging and therapeutic treatments, which should bring the necessary information and therapeutic results with the smallest amount of administered activity. Overall, the system implemented should be customer (patient) oriented in order to guarantee a service that meets the highest achievable professional standards. Departmental organization should include QC

  20. Cell to Cell Variability of Radiation-Induced Foci: Relation between Observed Damage and Energy Deposition.

    Directory of Open Access Journals (Sweden)

    Gaëtan Gruel

    Full Text Available Most studies that aim to understand the interactions between different types of photon radiation and cellular DNA assume homogeneous cell irradiation, with all cells receiving the same amount of energy. The level of DNA damage is therefore generally determined by averaging it over the entire population of exposed cells. However, evaluating the molecular consequences of a stochastic phenomenon such as energy deposition of ionizing radiation by measuring only an average effect may not be sufficient for understanding some aspects of the cellular response to this radiation. The variance among the cells associated with this average effect may also be important for the behaviour of irradiated tissue. In this study, we accurately estimated the distribution of the number of radiation-induced γH2AX foci (RIF per cell nucleus in a large population of endothelial cells exposed to 3 macroscopic doses of gamma rays from 60Co. The number of RIF varied significantly and reproducibly from cell to cell, with its relative standard deviation ranging from 36% to 18% depending on the macroscopic dose delivered. Interestingly, this relative cell-to-cell variability increased as the dose decreased, contrary to the mean RIF count per cell. This result shows that the dose effect, in terms of the number of DNA lesions indicated by RIF is not as simple as a purely proportional relation in which relative SD is constant with dose. To analyse the origins of this observed variability, we calculated the spread of the specific energy distribution for the different target volumes and subvolumes in which RIF can be generated. Variances, standard deviations and relative standard deviations all changed similarly from dose to dose for biological and calculated microdosimetric values. This similarity is an important argument that supports the hypothesis of the conservation of the association between the number of RIF per nucleus and the specific energy per DNA molecule. This

  1. Quality assurance of activity measurements in nuclear medicine and radiation protection

    International Nuclear Information System (INIS)

    This report contains 29 contributions. Only measurements with instruments were considered that have a reading for the radionuclide-specific activity in Bq, Bq/cm2, or Bq/cm3. This class of instruments covers, for example, radionuclide calibrators and contamination monitors. In the individual contributions, the basic physical concepts essential for activity measurements, the construction and calibration of the instruments, aspects of quality assurance from the producer's and applier's point of view, and the relevant regulations and standards are treated. Results of the detailed discussions that followed the lecture programme and referred separately to aspects of nuclear medicine and radiation protection are summarized. (orig./DG)

  2. Activities in connection with quality assurance in radiation therapy performed in Argentina: physical aspects

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, R.O.

    1984-06-01

    Quality assurance in radiotherapy is performed in different ways in Argentina than in other countries. A part of this program is carried out by the Secondary Standard Dosimetry Laboratory (SSDL-WHO/IAEA), which is a part of the Atomic Energy Commission. This laboratory organizes TLD postal intercomparison; calibrates and checks radiotherapy units and dosimeters; gives education in the physics of radiotherapy; has collaborated in the production of rules for the operation of radiation therapy units and maintains the application of these rules. A description of the activities of the SSDL and a brief explanation about the other activities, the present situation and future plans are discussed.

  3. Measurement of a high electrical quality factor in a niobium resonator for a gravitational radiation detector

    Science.gov (United States)

    Folkner, W. M.; Moody, M. V.; Richard, J.-P.

    1989-01-01

    The mechanical and electrical quality factors of a 10-g niobium resonator were measured at 4.4 K and were found to be 8.1 x 10 to the 6th, and 3.8 x 10 to the 6th, respectively. The value for the electrical quality factor is high enough for a system operating at 50 mK at a sensitivity level of one phonon. The resonator's low damping properties make it suitable for use as a transducer for a cryogenic three-mode gravitational radiation detector. A practical design is given for the mounting of the resonator on a 2400-kg aluminum-bar detector. Projections are made for the sensitivity of a 2400-kg bar instrumented as a three-mode system with this resonator inductively coupled to a SQUID.

  4. Evaluation of fruit productivity and quality in Hass avocado submitted to 60Co gamma radiation

    International Nuclear Information System (INIS)

    Evaluation of productivity, postharvest behavior and fruit quality was performed on four years Hass avocado trees irradiated with 60 Co gamma rays in doses of 5, 10, 15, 20 and 25 Gy, established in the ''La Labor'' Experimental Center of the Centro de Investigaciones Cientificas y Tecnologias del Aguacate en el Estado de Mexico (CICTAMEX) at Temascaltepec Mexico. Productivity had a significant increase in the dose of 15 Gy being the average number of fruits nearly 400 % more than the control at fruit setting, being such difference reduced at fruit harvesting to 300 %. In regard to postharvest performance, the respiration index (mg CO2/kg/hr) did not show significant differences among treatments. Also others variables such as physiological weight losses, texture, maturity pattern, and sensorial tests (color, flavor, aroma, texture) were not different in regard to the control. This mean that radiation has altered productivity but not the quality and postharvest behavior of fruits. (Author)

  5. Explicit and convex optimization of plan quality measures in intensity-modulated radiation therapy treatment planning

    CERN Document Server

    Engberg, Lovisa; Forsgren, Anders; Hårdemark, Björn

    2016-01-01

    Given the widespread agreement that doses-at-volume play important roles in quality assessment of radiation therapy treatment plans, planning objectives that correlate well with explicit dose-at-volume optimization are likely to correlate well with plan quality. In this study, planning objectives are formulated to explicitly either minimize or maximize convex approximations of dose-at-volume, namely, mean-tail-doses. This is in contrast to the conventionally used planning objectives, which are used to maximize clinical goal fulfilment by relating to deviations from dose-at-volume thresholds. Advantages of the proposed planning objectives are investigated through juxtaposition with conventional objectives in a computational study of two patient cases, each with three doses-at-volume to be minimized subject to PTV coverage. With proposed planning objectives, this is translated into minimizing three mean-tail-doses. Comparison with conventional objectives is carried out in the dose-at-volume domain and in the no...

  6. Evaluation gives productivity and quality gives fruit in Aguacate subjected has to gamma radiation

    International Nuclear Information System (INIS)

    Evaluation of productivity, post harvest behavior and fruit quality was performed on four years Has avocado trees irradiated with 60 Co gamma rays in doses of 5, 10, 15, 20 and 25 Gy, established in the La Labor Experimental Center of the Centro de Investigaciones Cientificas y Tecnologicas del Aguacate en el Estado de Mexico (CICTAMEX) at Temascaltepec Mexico. Productivity had a significant increase in the dose of 15 Gy being the average number of fruits nearly 400 % more than the control at fruit setting, being such difference reduced at fruit harvesting to 300%. In regard to post harvest performance, the respiration index (mg CO2 /kg/hr) did not show significant differences among treatments. Also others variables such as physiological weight losses, texture, maturity pattern, and sensorial tests (color, flavor, aroma, texture) were not different in regard to the control. This means that radiation has altered productivity but not the quality and post harvest behavior of fruits

  7. Quality control of calibration system for area monitors at National Laboratory of Metrology from Ionizing Radiations (LNMRI)

    International Nuclear Information System (INIS)

    The quality control of equipment used in calibration from the National Laboratory of Metrology on Ionizing Radiations is presented, with results of standard measure systems and irradiation system. Tables and graphics with the quality of systems are also shown. (C.G.C.)

  8. Quality control methodology and implementation of X-radiation standards beams, mammography level, following the standard IEC 61267

    Energy Technology Data Exchange (ETDEWEB)

    Correa, E.L.; Vivolo, V. [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN), Avenida Professor Lineu Prestes 2242, Cidade Universitaria, Sao Paulo, SP (Brazil); Potiens, M.P.A., E-mail: mppalbu@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN), Avenida Professor Lineu Prestes 2242, Cidade Universitaria, Sao Paulo, SP (Brazil)

    2012-07-15

    This study presents the results of the establishment of a quality control program developed and applied for the X-ray system of the Calibration Laboratory of IPEN. The X-ray standard beams, mammography level, using molybdenum and aluminum as additional filtration were established after the application of this quality control and the spectrometry of these qualities was made. The reference ionization chamber has traceability to the PTB. The radiation qualities RQR-M, RQA-M, RQN-M and RQB-M, following the recommendations of the IEC 61267 and the IAEA TRS 457 were established. - Highlights: Black-Right-Pointing-Pointer Determination of the additional filtration for each mammography radiation quality. Black-Right-Pointing-Pointer Determination of the KQ values for the WAV and WMV radiation qualities. Black-Right-Pointing-Pointer Determination of the air-kerma rates for all radiation qualities. Black-Right-Pointing-Pointer The uncertainties have been calculated using the type A and type B uncertainties. Black-Right-Pointing-Pointer Establishment of the qualities that use a PMMA phantom (WAN, WAB, WMN and WMB).

  9. Toward consistent cell segmentation: quality assessment of cell segments via appearance and geometry features

    Science.gov (United States)

    Brinker, Andrew; Fredrikson, Annika; Zhang, Xiaofan; Sourvenir, Richard; Zhang, Shaoting

    2015-03-01

    Computer-Aided Diagnosis (CAD) systems based on histopathological images rely on quality low-level image processing, including cell segmentation. Many methods for cell segmentation lack in generality and struggle with the wide variety of cell appearance and inter-cell structure present in histopathological images. We present a computationally efficient system to classify segmentation results as the first step toward automatic segment correction. This general method can applied to existing or future cell segmentation methods to provide corrections for low-quality results. Specifically, with a small collection of easy-to-compute features, we can identify incorrect segments with a high degree of accuracy, which then can be used to determine the needed corrections based on the type of segmentation failure present.

  10. Does Quality of Radiation Therapy Predict Outcomes of Multicenter Cooperative Group Trials? A Literature Review

    International Nuclear Information System (INIS)

    Central review of radiation therapy (RT) delivery within multicenter clinical trials was initiated in the early 1970s in the United States. Early quality assurance publications often focused on metrics related to process, logistics, and timing. Our objective was to review the available evidence supporting correlation of RT quality with clinical outcomes within cooperative group trials. A MEDLINE search was performed to identify multicenter studies that described central subjective assessment of RT protocol compliance (quality). Data abstracted included method of central review, definition of deviations, and clinical outcomes. Seventeen multicenter studies (1980-2012) were identified, plus one Patterns of Care Study. Disease sites were hematologic, head and neck, lung, breast, and pancreas. Between 0 and 97% of treatment plans received an overall grade of acceptable. In 7 trials, failure rates were significantly higher after inadequate versus adequate RT. Five of 9 and 2 of 5 trials reported significantly worse overall and progression-free survival after poor-quality RT, respectively. One reported a significant correlation, and 2 reported nonsignificant trends toward increased toxicity with noncompliant RT. Although more data are required, protocol-compliant RT may decrease failure rates and increase overall survival and likely contributes to the ability of collected data to answer the central trial question

  11. Quality assurance programme in the external dosimetry laboratory of the center for radiation protection of Cuba

    International Nuclear Information System (INIS)

    Full text: The External Dosimetry Laboratory (LDE) of the Center for Radiation Protection and Hygiene (CPHR) is the central dosimetry service of the country, which assures the individual monitoring on a monthly basis of about 5500 workers in 1000 establishments and maintains the National Dose Registry System. A project for upgrading the personal dosimetry service was started in 2000. In March 2001 film dosimeters began to gradually replaced by TLDs, the latter becoming the only official dosimeter a year later. In order to maintain quality and ensure compliance with regulations and international recommendations, a quality assurance culture has been introduced into the laboratory and quality requirements have been developed and implemented in the daily work through the establishment of a quality assurance (QA) programme. The design of the QA programme is based on the criteria contained in the ISO, on the recommendations of the IEC, and IAEA, as well as on regulations of the National Accreditation Council. The present study deals with the structure of the Laboratory's QA programme and includes documentation, organizational and managerial aspects as well as the procedures that are implemented. The experience gained during the years of the use of the QA programme is also described. (author)

  12. Immobilization of microbial cell and yeast cell and its application to biomass conversion using radiation techniques

    International Nuclear Information System (INIS)

    The recent results of immobilization of cellulase-producing cells and ethanol-fermentation yeast by radiation were reported. The enzyme of cellulase produced by immobilized cells was used for saccharification of lignocellulosic wastes and immobilized yeast cells were used for fermentation reaction from glucose to ethanol. The wastes such as chaff and bagasse were treated by γ-ray or electron-beam irradiation in the presence of alkali and subsequent mechanical crushing, to form a fine powder less than 50 μm in diameter. On the other hand, Trichoderma reesei as a cellulase-producing microbial cell was immobilized on a fibrous carrier having a specific porous structure and cultured to produce cellulase. The enzymatic saccharification of the pretreated waste was carried out using the produced cellulase. The enhanced fermentation process to produce ethanol from glucose with the immobilized yeast by radiation was also studied. The ethanol productivity of immobilized growing yeast cells thus obtained was thirteen times that of free yeast cells in a 1:1 volume of liquid medium to immobilized yeast cells. (author)

  13. Immobilization of microbial cell and yeast cell and its application to biomass conversion using radiation techniques

    Science.gov (United States)

    Kaetsu, Isao; Kumakura, Minoru; Fujimura, Takashi; Kasai, Noboru; Tamada, Masao

    The recent results of immobilization of cellulase-producing cells and ethanol-fermentation yeast by radiation were reported. The enzyme of cellulase produced by immobilized cells was used for saccharification of lignocellulosic wastes and immobilized yeast cells were used for fermentation reaction from glucose to ethanol. The wastes such as chaff and bagasse were treated by γ-ray or electron-beam irradiation in the presence of alkali and subsequent mechanical crushing, to form a fine powder less than 50 μm in diameter. On the other hand, Trichoderma reesei as a cellulase-producing microbial cell was immobilized on a fibrous carrier having a specific porous structure and cultured to produce cellulase. The enzymatic saccharification of the pretreated waste was carried out using the produced cellulase. The enhanced fermentation process to produce ethanol from glucose with the immobilized yeast by radiation was also studied. The ethanol productivity of immobilized growing yeast cells thus obtained was thirteen times that of free yeast cells in a 1:1 volume of liquid medium to immobilized yeast cells.

  14. Quality control methodology and implementation of X-radiation standards beams, mammography level, following the standard IEC 61267

    International Nuclear Information System (INIS)

    In this work it was developed and applied a quality control program of the X radiation system (160 kV, constant potential, target of tungsten) of the Calibration Laboratory of IPEN(LCI) in the energy range relative to mammography beams (from 25 kV to 35 kV). The X radiation standards beams, level mammography, using molybdenum and aluminum as additional filtration, were established after the application of this quality control program following national and international recommendations. The reference ionization chamber has traceability to PTB and was regularly submitted to quality control tests for evaluation and analysis of its performance. The radiation qualities emerging from the X-radiation assembly (RQR-M), based on a phantom made up of an aluminum added filter (RQA-M), narrow beam condition (RQN-M) and broad beam condition (RQB-M), following the recommendations of the international standard IEC 61267 (2005) and the IAEA code of practice, TRS 457 (2007) were established. For the implantation of RQN-M and RQB-M radiation qualities, two mammography phantoms were developed. The half-value layers found are those presented by the German primary laboratory PTB, and varied from 0.35 to 1.21 mm Al. The air kerma rates were obtained for all the 15 implanted qualities. (author)

  15. Combination of aloe-emodin with radiation enhances radiation effects and improves differentiation in human cervical cancer cells.

    Science.gov (United States)

    Luo, Jinghua; Yuan, Yong; Chang, Pengyu; Li, Dawei; Liu, Zhiqiang; Qu, Yaqin

    2014-08-01

    The aim of the present study was to investigate the effects of aloe-emodin (AE) on the radiosensitivity and differentiation of HeLa human cervical cancer cells. Cell proliferation was assessed in the HeLa cervical cancer cell line by a methylthiazolyldiphenyl-tetrazolium bromide assay. Radiosensitivity was determined by a colony‑forming assay. Flow cytometry was used for analysis of cell cycle distribution and apoptosis. The expression of γ-H2AX and cyclin B was assessed by western blotting. Alkaline phosphatase (ALP) activity was measured by an ALP activity kit. It was demonstrated that AE inhibited the proliferation of HeLa cells in a concentration- and time-dependent manner, induced G2/M and S phase cell cycle arrest and enhanced the radiosensitivity of HeLa cells. The combination of AE and radiation induced apoptosis, upregulated cyclin B and γ-H2AX expression and further improved ALP activity compared with treatment with AE or radiation alone. AE enhanced the radiosensitivity of HeLa human cervical cancer cells in vitro, inhibited the proliferation of HeLa cells, induced G2/M phase cell cycle arrest and, in combination with radiation, induced the apoptosis and improved the differentiation of HeLa cells. PMID:24920336

  16. Radiation-induced recovery processes in cultured marsupial cells

    International Nuclear Information System (INIS)

    The ultraviolet sensitivity of Potorous tridactylus male kidney (PtK-2) cells is markedly increased by post irradiation treatment for 24 h with 5 μM emetine of with 5 μM cycloheximide or with the RNA polymerase II inhibitor 5,6-dichloro-1-β-ribofuranosylbenzimidazole at 50 μM. All 3 treatments give the same sensitivity, while unirradiated cells are little affected. Shortening the time of treatment, of delaying application of the drugs decreases their effects on the same time schedule. Preiiradiation of cells, with no drug treatment in the following 8 h, diminishes the sensitivity to a subsequent irradiation with protein synthesis blocked afterwards. Photoreactivation immediately following such preiiradiation eliminated its desensitizing effect. Inhibiting protein synthesis after irradiation also markedly reduces the frequency of UV-induced mutants in the surviving population. These facts suggest that gene expression in the period following iradiation facilitates recovery from radiation damage, with an increased probability of mutation, reminiscent of the 'SOS response' in Escherichia coli. (author). 29 refs.; 5 figs.; 3 tabs

  17. Imaging and radiation effects of gold nanoparticles in tumour cells

    Science.gov (United States)

    McQuaid, Harold N.; Muir, Mark F.; Taggart, Laura E.; McMahon, Stephen J.; Coulter, Jonathan A.; Hyland, Wendy B.; Jain, Suneil; Butterworth, Karl T.; Schettino, Giuseppe; Prise, Kevin M.; Hirst, David G.; Botchway, Stanley W.; Currell, Fred J.

    2016-01-01

    Gold nanoparticle radiosensitization represents a novel technique in enhancement of ionising radiation dose and its effect on biological systems. Variation between theoretical predictions and experimental measurement is significant enough that the mechanism leading to an increase in cell killing and DNA damage is still not clear. We present the first experimental results that take into account both the measured biodistribution of gold nanoparticles at the cellular level and the range of the product electrons responsible for energy deposition. Combining synchrotron-generated monoenergetic X-rays, intracellular gold particle imaging and DNA damage assays, has enabled a DNA damage model to be generated that includes the production of intermediate electrons. We can therefore show for the first time good agreement between the prediction of biological outcomes from both the Local Effect Model and a DNA damage model with experimentally observed cell killing and DNA damage induction via the combination of X-rays and GNPs. However, the requirement of two distinct models as indicated by this mechanistic study, one for short-term DNA damage and another for cell survival, indicates that, at least for nanoparticle enhancement, it is not safe to equate the lethal lesions invoked in the local effect model with DNA damage events.

  18. 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.

  19. Establishment of the mammographic radiation qualities in industrial equipment: spectra determination

    International Nuclear Information System (INIS)

    In this work, a Si(Li) detector was used to analyze mammographic X-ray spectra produced by an industrial equipment with Molybdenum (Mo) target, operating at constant tube potentials between 20 and 35 kV. Filters of Mo and Al of suitable thickness were added to the tube exit, in order to reproduce the radiation qualities of an X-ray mammographic equipment, as recommended by the International Electrotechnical Commission (IEC 61267) and the Physikalisch-Technischen Bundesanstalt (PTB). A detailed evaluation of the detector response functions was made using Monte Carlo simulations. The validity of this method was tested through comparisons with the experimental spectra of radioactive sources. The results showed that the Si(Li) detector exhibits good response function in low energy (between 5 and 20 keV). The measured X-ray spectra for a Mo filtration (0.03 mm thickness), corrected using the response functions, show a good agreement with the reference clinical spectra. The results of this work also show that both the radiation qualities implemented and the spectra shape are consistent with that obtained for mammographic X-ray beams, and they can be applied to calibration of the mammography measurements instruments (e.g. ionization chambers and dosimeters).

  20. Multichannel Data Acquisition System comparison for Quality Assurance in external beam radiation therapy

    International Nuclear Information System (INIS)

    Megavoltage photon radiation therapies are widely used in modern cancer treatment. The improvement of the treatment has lead to the need of Quality Assurance (QA) devices to detect malfunctioning or human mistakes during the planning phase and treatment verification. Active electronic devices for 2D or 3D QA in external beam radiotherapy are typically based on analogue/digital mixed signal Data Acquisition Systems (DAS) which are required to have high spatial resolution, large dynamic range, high sensitivity, large numbers of channels and fast real-time capabilities. The Centre of Medical Radiation Physics (CMRP) has developed several multichannel DAS architectures based on different analogue front-ends to suit a wide range of radiotherapy applications. For the purpose of this study, two DAS, with different front-ends, have been equipped with 128 channels and tested in a clinical environment. Data show a good agreement within 1% between the two systems and the ionising chamber currently used for daily QA. - Highlights: • Two multichannels Data Acquisition Systems (DAS A and B) have been designed by the CMRP for Quality Assurance purposes. • The DAS have been tested and compared to ion chamber showing agreement of the results within 1%. • DAS have been used to characterise megavoltage LINAC beam profile and timing performances

  1. A program on quality assurance and dose calibration for radiation therapy units in Venezuela

    International Nuclear Information System (INIS)

    The results of a five year program (1988-90-91-92-93) on quality assurance and dose calibration for 12 Cobalt-60 units from public hospitals, which represents 30% of total radiation therapy units in Venezuela, are presented. The remarkable improvement in the general performance of these units can be seen in the IAEA/WHO Postal TLD Intercomparison results which gave 100% within ± 5% in 1990 and 1992, while 63% in 1990 and 44% in 1992, with errors up to 37% were obtained for the participants not included in the program. The difference between the two groups lead the government to decrete through the Gaceta Oficial de la Republica de Venezuela, Resolution G-1397 on March 3, 1993, the quality assurance and dose calibration programs shall be established for all radiation therapy installations in Venezuela. The project for the standards was developed by the SSDL physicists and it was already approbated by the Health Ministry. It is expected that the Norms will enter into effect by the end of 1994. (author). 14 refs, 1 fig., 3 tabs

  2. Quality assurance for radon exposure chambers at the National Air and Radiation Environmental Laboratory, Montgomery, Alabama

    Energy Technology Data Exchange (ETDEWEB)

    Semler, M.O.; Sensintaffar, E.L. [National Air and Radiation Environmental Laboratory, Montgomery, AL (United States)

    1993-12-31

    The Office of Radiation and Indoor Air, U.S. Environmental Protection Agency (EPA), operates six radon exposure chambers in its two laboratories, the National Air and Radiation Environmental Laboratory (NAREL) in Montgomery, Alabama, and the Las Vegas Facility, Las Vegas, Nevada. These radon exposure chambers are used to calibrate and test portable radon measuring instruments, test commercial suppliers of radon measurement services through the Radon Measurement Proficiency Program, and expose passive measurement devices to known radon concentrations as part of a quality assurance plan for federal and state studies measuring indoor radon concentrations. Both laboratories participate in national and international intercomparisons for the measurement of radon and are presently working with the National Institute of Standards and Technology (NIST) to receive a certificate of traceability for radon measurements. NAREL has developed an estimate of the total error in its calibration of each chamber`s continuous monitors as part of an internal quality assurance program. This paper discusses the continuous monitors and their calibration for the three chambers located in Montgomery, Alabama, as well as the results of the authors intercomparisons and total error analysis.

  3. The peer review system (PRS) for quality assurance and treatment improvement in radiation therapy

    Science.gov (United States)

    Le, Anh H. T.; Kapoor, Rishabh; Palta, Jatinder R.

    2012-02-01

    Peer reviews are needed across all disciplines of medicine to address complex medical challenges in disease care, medical safety, insurance coverage handling, and public safety. Radiation therapy utilizes technologically advanced imaging for treatment planning, often with excellent efficacy. Since planning data requirements are substantial, patients are at risk for repeat diagnostic procedures or suboptimal therapeutic intervention due to a lack of knowledge regarding previous treatments. The Peer Review System (PRS) will make this critical radiation therapy information readily available on demand via Web technology. The PRS system has been developed with current Web technology, .NET framework, and in-house DICOM library. With the advantages of Web server-client architecture, including IIS web server, SOAP Web Services and Silverlight for the client side, the patient data can be visualized through web browser and distributed across multiple locations by the local area network and Internet. This PRS will significantly improve the quality, safety, and accessibility, of treatment plans in cancer therapy. Furthermore, the secure Web-based PRS with DICOM-RT compliance will provide flexible utilities for organization, sorting, and retrieval of imaging studies and treatment plans to optimize the patient treatment and ultimately improve patient safety and treatment quality.

  4. Weighting factors for radiation quality: How to unite the two current concepts

    International Nuclear Information System (INIS)

    The quality factor, Q(L), used to be the universal weighting factor to account for radiation quality, until - in its 1991 Recommendations - the ICRP established a dichotomy between 'computable' and 'measurable' quantities. The new concept of the radiation weighting factor, wR, was introduced for use with the 'computable' quantities, such as the effective dose, E. At the same time, the application of Q(L) was restricted to 'measurable' quantities, such as the operational quantities ambient dose equivalent or personal dose equivalent. The result has been a dual system of incoherent dosimetric quantities. The most conspicuous inconsistency resulted for neutrons, for which the new concept of wR had been primarily designed. While its definition requires an accounting for the gamma rays produced by neutron capture in the human body, this effect is not adequately reflected in the numerical values of wR, which are now suitable for mice, but are - at energies of the incident neutrons below 1 MeV - conspicuously too large for man. A recent Report 92 to ICRP has developed a proposal to correct the current imbalance and to define a linkage between the concepts Q(L) and wR. The proposal is here considered within a broader assessment of the rationale that led to the current dual system of dosimetric quantities. (authors)

  5. Quality assurance for radon exposure chambers at the National Air and Radiation Environmental Laboratory, Montgomery, Alabama

    International Nuclear Information System (INIS)

    The Office of Radiation and Indoor Air, U.S. Environmental Protection Agency (EPA), operates six radon exposure chambers in its two laboratories, the National Air and Radiation Environmental Laboratory (NAREL) in Montgomery, Alabama, and the Las Vegas Facility, Las Vegas, Nevada. These radon exposure chambers are used to calibrate and test portable radon measuring instruments, test commercial suppliers of radon measurement services through the Radon Measurement Proficiency Program, and expose passive measurement devices to known radon concentrations as part of a quality assurance plan for federal and state studies measuring indoor radon concentrations. Both laboratories participate in national and international intercomparisons for the measurement of radon and are presently working with the National Institute of Standards and Technology (NIST) to receive a certificate of traceability for radon measurements. NAREL has developed an estimate of the total error in its calibration of each chamber's continuous monitors as part of an internal quality assurance program. This paper discusses the continuous monitors and their calibration for the three chambers located in Montgomery, Alabama, as well as the results of the authors intercomparisons and total error analysis

  6. Radiation

    International Nuclear Information System (INIS)

    The chapter one presents the composition of matter and atomic theory; matter structure; transitions; origin of radiation; radioactivity; nuclear radiation; interactions in decay processes; radiation produced by the interaction of radiation with matter

  7. Association Between White Blood Cell Count Following Radiation Therapy With Radiation Pneumonitis in Non-Small Cell Lung Cancer

    International Nuclear Information System (INIS)

    Purpose: Radiation pneumonitis (RP) is an inflammatory response to radiation therapy (RT). We assessed the association between RP and white blood cell (WBC) count, an established metric of systemic inflammation, after RT for non-small cell lung cancer. Methods and Materials: We retrospectively analyzed 366 patients with non-small cell lung cancer who received ≥60 Gy as definitive therapy. The primary endpoint was whether WBC count after RT (defined as 2 weeks through 3 months after RT completion) was associated with grade ≥3 or grade ≥2 RP. Median lung volume receiving ≥20 Gy (V20) was 31%, and post-RT WBC counts ranged from 1.7 to 21.2 × 103 WBCs/μL. Odds ratios (ORs) associating clinical variables and post-RT WBC counts with RP were calculated via logistic regression. A recursive-partitioning algorithm was used to define optimal post-RT WBC count cut points. Results: Post-RT WBC counts were significantly higher in patients with grade ≥3 RP than without (P3/μL for grade ≥3 and ≥2 RP, respectively. Univariate analysis revealed significant associations between post-RT WBC count and grade ≥3 (n=46, OR=2.6, 95% confidence interval [CI] 1.4‒4.9, P=.003) and grade ≥2 RP (n=164, OR=2.0, 95% CI 1.2‒3.4, P=.01). This association held in a stepwise multivariate regression. Of note, V20 was found to be significantly associated with grade ≥2 RP (OR=2.2, 95% CI 1.2‒3.4, P=.01) and trended toward significance for grade ≥3 RP (OR=1.9, 95% CI 1.0-3.5, P=.06). Conclusions: Post-RT WBC counts were significantly and independently associated with RP and have potential utility as a diagnostic or predictive marker for this toxicity

  8. GaAs quantum dot solar cell under concentrated radiation

    International Nuclear Information System (INIS)

    Effects of concentrated solar radiation on photovoltaic performance are investigated in well-developed GaAs quantum dot (QD) solar cells with 1-Sun efficiencies of 18%–19%. In these devices, the conversion processes are enhanced by nanoscale potential barriers and/or AlGaAs atomically thin barriers around QDs, which prevent photoelectron capture to QDs. Under concentrated radiation, the short circuit current increases proportionally to the concentration and the open circuit voltage shows the logarithmic increase. In the range up to hundred Suns, the contributions of QDs to the photocurrent are proportional to the light concentration. The ideality factors of 1.1–1.3 found from the VOC-Sun characteristics demonstrate effective suppression of recombination processes in barrier-separated QDs. The conversion efficiency shows the wide maximum in the range of 40–90 Suns and reaches 21.6%. Detailed analysis of I-V-Sun characteristics shows that at low intensities, the series resistance decreases inversely proportional to the concentration and, at ∼40 Suns, reaches the plateau determined mainly by the front contact resistance. Improvement of contact resistance would increase efficiency to above 24% at thousand Suns

  9. Results of radiation therapy for squamous cell carcinoma of vulva

    International Nuclear Information System (INIS)

    From 1962 to 1982, 20 cases of patients with squamous cell carcinoma of the vulva were treated by radiation alone at National Cancer Center Hospital, Tokyo. 80% (16/20) of these cases were over 60 years old. Treatment was made by interstitial irradiation (Radium needle or Au-Grain) and external irradiation (Betatron electron or Linac X-rays), alone or with various combinations. As for the stage of these cases, Stage I was 3 cases (15%), Stage II was 5 (25%) and Stage III was 12 (60%). Serious complications after treatment were observed in 15% (3/20) and all cases were treated with external irradiation alone. The 5 year survival rates by stage were as follows; Stage I 100% (3/3), Stage II 50% (2/4) and Stage III 22.2% (2/9). Surgery is considered the treatment of choice in this disease. However, radiation therapy may be indicated when the tumor has extended beyond the limit of surgical resections; when distant metastases are present; when the patient's general condition precludes surgery, or when surgery is refused. (author)

  10. Results of radiation therapy for squamous cell carcinoma of vulva

    Energy Technology Data Exchange (ETDEWEB)

    Tsukiyama, Iwao; Kakehi, Masae; Ono, Ryosuke (National Cancer Center, Tokyo (Japan). Hospital)

    1984-04-01

    From 1962 to 1982, 20 cases of patients with squamous cell carcinoma of the vulva were treated by radiation alone at National Cancer Center Hospital, Tokyo. 80% (16/20) of these cases were over 60 years old. Treatment was made by interstitial irradiation (Radium needle or Au-Grain) and external irradiation (Betatron electron or Linac X-rays), alone or with various combinations. As for the stage of these cases, Stage I was 3 cases (15%), Stage II was 5 (25%) and Stage III was 12 (60%). Serious complications after treatment were observed in 15% (3/20) and all cases were treated with external irradiation alone. The 5 year survival rates by stage were as follows; Stage I 100% (3/3), Stage II 50% (2/4) and Stage III 22.2% (2/9). Surgery is considered the treatment of choice in this disease. However, radiation therapy may be indicated when the tumor has extended beyond the limit of surgical resections; when distant metastases are present; when the patient's general condition precludes surgery, or when surgery is refused.

  11. GaAs quantum dot solar cell under concentrated radiation

    Science.gov (United States)

    Sablon, K.; Li, Y.; Vagidov, N.; Mitin, V.; Little, J. W.; Hier, H.; Sergeev, A.

    2015-08-01

    Effects of concentrated solar radiation on photovoltaic performance are investigated in well-developed GaAs quantum dot (QD) solar cells with 1-Sun efficiencies of 18%-19%. In these devices, the conversion processes are enhanced by nanoscale potential barriers and/or AlGaAs atomically thin barriers around QDs, which prevent photoelectron capture to QDs. Under concentrated radiation, the short circuit current increases proportionally to the concentration and the open circuit voltage shows the logarithmic increase. In the range up to hundred Suns, the contributions of QDs to the photocurrent are proportional to the light concentration. The ideality factors of 1.1-1.3 found from the VOC-Sun characteristics demonstrate effective suppression of recombination processes in barrier-separated QDs. The conversion efficiency shows the wide maximum in the range of 40-90 Suns and reaches 21.6%. Detailed analysis of I-V-Sun characteristics shows that at low intensities, the series resistance decreases inversely proportional to the concentration and, at ˜40 Suns, reaches the plateau determined mainly by the front contact resistance. Improvement of contact resistance would increase efficiency to above 24% at thousand Suns.

  12. Strengthening activity measurement quality in radiation protection - from metrological science to reliable end-user application

    International Nuclear Information System (INIS)

    In many fields of radiation protection - e.g. internal dosimetry, nuclear medicine, radioecology, NORM - accurate and reliable activity measurements are of fundamental significance on meaningful evaluation of radiation exposure caused by radioactivity. Although the physical quantity activity and its SI unit Becquerel are very easy to define theoretically, the real practical activity measurement of radionuclides in different media is always a highly sophisticated and challenging task. Effective ways to ensure traceability of unit Bq for all radionuclides of interest from national metrological standards to qualified end-user measurements are calibration and/or verification of instruments and methods. The surveillance of competence and quality of activity measurements is additionally ensured by intercomparison exercises on national, regional or international levels. In this paper, recent improvements, developments and practical implementation on the quantification of activity of radionuclides in the field of radiation protection from fundamental metrology to robust end-user applications in Austria are covered. The Austrian experience in verification and calibration of activity measurement instruments is as much addressed as the conclusions on intercomparison exercises on gamma-ray spectrometry and radon measurement methods. Different evaluation methods are shown with regard to the statistical evaluation basis. Reasonable and practically applicable statistical modelling and parameterization based on the results and experience is proposed. Statistically based criteria for the evaluation of conformity of activity measurement instruments and methods with technical and legal requirements are presented. Eventually cooperation within the European and international networks in radionuclide metrology, EURAMET and ICRM respectively, is discussed. (author)

  13. Effect of gamma radiation and storage on cashew apple (Anacardium occidentale L.) quality

    International Nuclear Information System (INIS)

    The non-efficiency or absence of techniques for adequate handling, transport, and storage of cashew stalks associated with a high level of perishability, generates high economic loss in the commercialization of these fruits, hence the development of conservation methods becomes a necessity in order to enhance the profitability. Cashew apples from precocious dwarf cashew tree were irradiated with doses of 0, 0.5, and 1.0 kGy and stored during nine days under refrigeration at 4 ºC for evaluation of the quality stability during storage. Chemical analyses were performed to verify changes in reducing sugars, Brix, vitamin C, and pH. Alterations in the firmness and color were also observed. The levels of vitamin C decreased as a function of storage as well as a function of the radiation doses employed. The firmness of the fruits was influenced by both the radiation doses and storage time, increasing during storage and decreasing as the radiation doses increased. Irradiation was shown to be efficient in the prolongation of the shelf-life of cashew stalks. (author)

  14. Quality assurance in radiation therapy: European experience - present and future clinical efforts

    International Nuclear Information System (INIS)

    A high standard of radiotherapeutic practice must be sought in all phases of management of a patient with malignant disease. Radiation therapy must be appropriately chosen and integrated with surgery, cytotoxic chemotherapy and all other modes of treatment. The most suitable technique with a dose, fractionation and time regime must devised and executed with technical and personal care. Follow-up to truly assess tumor control and morbidity is essential so as to guide the management of future patients. To achieve this in Europe great reliance is placed upon the training and qualification of the therapist and staff. High standards are applied to the profession