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Sample records for unit axis dose

  1. A two-dimensional matrix correction for off-axis portal dose prediction errors

    International Nuclear Information System (INIS)

    Bailey, Daniel W.; Kumaraswamy, Lalith; Bakhtiari, Mohammad; Podgorsak, Matthew B.

    2013-01-01

    Purpose: This study presents a follow-up to a modified calibration procedure for portal dosimetry published by Bailey et al. [“An effective correction algorithm for off-axis portal dosimetry errors,” Med. Phys. 36, 4089–4094 (2009)]. A commercial portal dose prediction system exhibits disagreement of up to 15% (calibrated units) between measured and predicted images as off-axis distance increases. The previous modified calibration procedure accounts for these off-axis effects in most regions of the detecting surface, but is limited by the simplistic assumption of radial symmetry. Methods: We find that a two-dimensional (2D) matrix correction, applied to each calibrated image, accounts for off-axis prediction errors in all regions of the detecting surface, including those still problematic after the radial correction is performed. The correction matrix is calculated by quantitative comparison of predicted and measured images that span the entire detecting surface. The correction matrix was verified for dose-linearity, and its effectiveness was verified on a number of test fields. The 2D correction was employed to retrospectively examine 22 off-axis, asymmetric electronic-compensation breast fields, five intensity-modulated brain fields (moderate-high modulation) manipulated for far off-axis delivery, and 29 intensity-modulated clinical fields of varying complexity in the central portion of the detecting surface. Results: Employing the matrix correction to the off-axis test fields and clinical fields, predicted vs measured portal dose agreement improves by up to 15%, producing up to 10% better agreement than the radial correction in some areas of the detecting surface. Gamma evaluation analyses (3 mm, 3% global, 10% dose threshold) of predicted vs measured portal dose images demonstrate pass rate improvement of up to 75% with the matrix correction, producing pass rates that are up to 30% higher than those resulting from the radial correction technique alone. As

  2. SU-F-T-473: Evaluation of Off-Axis And Peripheral Dose Using Different Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ganesan, B; Prakasarao, A; Singaravelu, G [Anna University, Chennai, TamilNadu (India); Palraj, T; Rai, R [Dr. Rai Memorial Cancer Institute, Chennai, TamilNadu (India)

    2016-06-15

    Purpose: In radiation therapy, measurement of off-axis and peripheral dose is a tedious task. The dose distribution along the beam central axis give only part of the information required for an accurate dose description inside the patient. Dose distributions in 2-D and 3-D are determined with central axis data in conjunction with off-axis dose profiles. Combining a central axis dose distribution with off-axis data results in volume dose matrix that provides 2-D and 3-D information on dose distribution. By considering the importance of these two parameters this study investigates and compares the off axis and peripheral dose measurement using Ionization chamber, MOSFET, Radiochromic film and EDR2 film. Methods: In the measurement of off-axis and peripheral doses 0.6cc farmer type chamber, EDR-2 film, MD-55 radiochromic film and MOSFET detectors were used for both 6MV and 15MV beams. The off-axis and peripheral dose was measured at every 1 cm interval by changing the position of the couch without disturbing the other experimental setup in particular, the phantom with detector position. Results: Readings were obtained for both 6MV and 15MV photon beams at SSD technique for various field size using MOSFET, Ionization chamber and Radiochromic film. The results shows the percentage difference between various detectors for various field sizes. For Peripheral dose measurement were taken from the edge of the field size and for off axis it is measured form central axis dose. Conclusion: In conclusion, our study shows that no detector is ideal and only a comparison between different detectors highlights the weaknesses of each detector. MOSFET provides adequate dose assessment in off-axis and peripheral regions in 6MV and 15MV photon beams. Film dosimetry in general a convenient method to generate one- and two-dimensional dose distributions. The result of this indicates that MOSFET is flexible tool for relative dosimetry as films.

  3. Patient dose in neonatal units

    International Nuclear Information System (INIS)

    Smans, K.; Struelens, L.; Smet, M.; Bosmans, H.; Vanhavere, F.

    2008-01-01

    Lung disease represents one of the most life-threatening conditions in prematurely born children. In the evaluation of the neonatal chest, the primary and most important diagnostic study is therefore the chest radiograph. Since prematurely born children are very sensitive to radiation, those radiographs may lead to a significant radiation detriment. Hence, knowledge of the patient dose is necessary to justify the exposures. A study to assess the patient doses was started at the neonatal intensive care unit (NICU) of the Univ. Hospital in Leuven. Between September 2004 and September 2005, prematurely born babies underwent on average 10 X-ray examinations in the NICU. In this sample, the maximum was 78 X-ray examinations. For chest radiographs, the median entrance skin dose was 34 μGy and the median dose area product was 7.1 mGy.cm 2 . By means of conversion coefficients, the measured values were converted to organ doses. Organ doses were calculated for three different weight classes: extremely low birth weight infants ( 2500 g). The doses to the lungs for a single chest radiograph for infants with extremely low birth weights, low birth weights and normal birth weights were 24, 25 and 32 μGy, respectively. (authors)

  4. Measurement of off-axis and peripheral skin dose using radiochromic film

    International Nuclear Information System (INIS)

    Butson, Martin J.; Yu, P.K.N.; Metcalfe, P.E.

    1998-01-01

    A radiotherapy skin dose profile can be obtained with radiochromic film. The central axis skin dose relative to D max for a 10x10cm 2 field size was found to be 22%, 17% and 15.5% for 6 MV, 10 MV and 18 MV photon beams. Peripheral dose increased with increasing field size. At 10 MV the skin dose 2 cm outside the geometric field edge was measured as 6%, 10% and 17% for 10x10cm 2 , 20x20cm 2 and 30x30cm 2 field sizes respectively. Off-axis skin dose decreased as distance increased from central axis for fields with Perspex block trays. For a 20x20cm 2 field, an approximately 5-8% drop in percentage skin dose was observed from central axis to the beam edge. (author)

  5. Research of z-axis geometric dose efficiency in multi-detector computed tomography

    International Nuclear Information System (INIS)

    Kim, You Hyun; Kim, Moon Chan

    2006-01-01

    With the recent prevalence of helical CT and multi-slice CT, which deliver higher radiation dose than conventional CT due to overbeaming effect in X-ray exposure and interpolation technique in image reconstruction. Although multi-detector and helical CT scanner provide a variety of opportunities for patient dose reduction, the potential risk for high radiation levels in CT examination can't be overemphasized in spite of acquiring more diagnostic information. So much more concerns is necessary about dose characteristics of CT scanner, especially dose efficient design as well as dose modulation software, because dose efficiency built into the scanner's design is probably the most important aspect of successful low dose clinical performance. This study was conducted to evaluate z-axis geometric dose efficiency in single detector CT and each level multi-detector CT, as well as to compare z-axis dose efficiency with change of technical scan parameters such as focal spot size of tube, beam collimation, detector combination, scan mode, pitch size, slice width and interval. The results obtained were as follows; 1. SDCT was most highest and 4 MDCT was most lowest in z-axis geometric dose efficiency among SDCT, 4, 8, 16, 64 slice MDCT made by GE manufacture. 2. Small focal spot was 0.67-13.62% higher than large focal spot in z-axis geometric dose efficiency at MDCT. 3. Large beam collimation was 3.13-51.52% higher than small beam collimation in z-axis geometric dose efficiency at MDCT. Z-axis geometric dose efficiency was same at 4 slice MDCT in all condition and 8 slice MDCT of large beam collimation with change of detector combination, but was changed irregularly at 8 slice MDCT of small beam collimation and 16 slice MDCT in all condition with change of detector combination. 5. There was no significant difference for z-axis geometric dose efficiency between conventional scan and helical scan, and with change of pitch factor, as well as change of slice width or interval for

  6. Improvements in dose calculation accuracy for small off-axis targets in high dose per fraction tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hardcastle, Nicholas; Bayliss, Adam; Wong, Jeannie Hsiu Ding; Rosenfeld, Anatoly B.; Tome, Wolfgang A. [Department of Human Oncology, University of Wisconsin-Madison, WI, 53792 (United States); Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, VIC 3002 (Australia) and Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia); Department of Human Oncology, University of Wisconsin-Madison, WI 53792 (United States); Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia) and Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur (Malaysia); Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia); Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53792 (United States); Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53792 (United States); Einstein Institute of Oncophysics, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461 (United States) and Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia)

    2012-08-15

    Purpose: A recent field safety notice from TomoTherapy detailed the underdosing of small, off-axis targets when receiving high doses per fraction. This is due to angular undersampling in the dose calculation gantry angles. This study evaluates a correction method to reduce the underdosing, to be implemented in the current version (v4.1) of the TomoTherapy treatment planning software. Methods: The correction method, termed 'Super Sampling' involved the tripling of the number of gantry angles from which the dose is calculated during optimization and dose calculation. Radiochromic film was used to measure the dose to small targets at various off-axis distances receiving a minimum of 21 Gy in one fraction. Measurements were also performed for single small targets at the center of the Lucy phantom, using radiochromic film and the dose magnifying glass (DMG). Results: Without super sampling, the peak dose deficit increased from 0% to 18% for a 10 mm target and 0% to 30% for a 5 mm target as off-axis target distances increased from 0 to 16.5 cm. When super sampling was turned on, the dose deficit trend was removed and all peak doses were within 5% of the planned dose. For measurements in the Lucy phantom at 9.7 cm off-axis, the positional and dose magnitude accuracy using super sampling was verified using radiochromic film and the DMG. Conclusions: A correction method implemented in the TomoTherapy treatment planning system which triples the angular sampling of the gantry angles used during optimization and dose calculation removes the underdosing for targets as small as 5 mm diameter, up to 16.5 cm off-axis receiving up to 21 Gy.

  7. Improvements in dose calculation accuracy for small off-axis targets in high dose per fraction tomotherapy

    International Nuclear Information System (INIS)

    Hardcastle, Nicholas; Bayliss, Adam; Wong, Jeannie Hsiu Ding; Rosenfeld, Anatoly B.; Tomé, Wolfgang A.

    2012-01-01

    Purpose: A recent field safety notice from TomoTherapy detailed the underdosing of small, off-axis targets when receiving high doses per fraction. This is due to angular undersampling in the dose calculation gantry angles. This study evaluates a correction method to reduce the underdosing, to be implemented in the current version (v4.1) of the TomoTherapy treatment planning software. Methods: The correction method, termed “Super Sampling” involved the tripling of the number of gantry angles from which the dose is calculated during optimization and dose calculation. Radiochromic film was used to measure the dose to small targets at various off-axis distances receiving a minimum of 21 Gy in one fraction. Measurements were also performed for single small targets at the center of the Lucy phantom, using radiochromic film and the dose magnifying glass (DMG). Results: Without super sampling, the peak dose deficit increased from 0% to 18% for a 10 mm target and 0% to 30% for a 5 mm target as off-axis target distances increased from 0 to 16.5 cm. When super sampling was turned on, the dose deficit trend was removed and all peak doses were within 5% of the planned dose. For measurements in the Lucy phantom at 9.7 cm off-axis, the positional and dose magnitude accuracy using super sampling was verified using radiochromic film and the DMG. Conclusions: A correction method implemented in the TomoTherapy treatment planning system which triples the angular sampling of the gantry angles used during optimization and dose calculation removes the underdosing for targets as small as 5 mm diameter, up to 16.5 cm off-axis receiving up to 21 Gy.

  8. Charpak, Garwin, propose unit for radiation dose

    CERN Multimedia

    Feder, Toni

    2002-01-01

    Becquerels, curries, grays, rads, rems, roentgens, sieverts - even for specialists the units of radiation can get confusing. That's why two eminent physicists, Georges Charpak of France, and Richard Garwin, are proposing the DARI as a unit of radiation dose they hope will help the public evaluate the risks associated with low-level radiation exposure (1 page)

  9. Topology optimization of inertia driven dosing units

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe

    2017-01-01

    This paper presents a methodology for optimizing inertia driven dosing units, sometimes referred to as eductors, for use in small scale flow applications. The unit is assumed to operate at low to moderate Reynolds numbers and under steady state conditions. By applying topology optimization...

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

    International Nuclear Information System (INIS)

    Keall, P.

    2001-01-01

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

  11. Derivation of electron and photon energy spectra from electron beam central axis depth dose curves

    Energy Technology Data Exchange (ETDEWEB)

    Deng Jun [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305 (United States)]. E-mail: jun@reyes.stanford.edu; Jiang, Steve B.; Pawlicki, Todd; Li Jinsheng; Ma, C.M. [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305 (United States)

    2001-05-01

    A method for deriving the electron and photon energy spectra from electron beam central axis percentage depth dose (PDD) curves has been investigated. The PDD curves of 6, 12 and 20 MeV electron beams obtained from the Monte Carlo full phase space simulations of the Varian linear accelerator treatment head have been used to test the method. We have employed a 'random creep' algorithm to determine the energy spectra of electrons and photons in a clinical electron beam. The fitted electron and photon energy spectra have been compared with the corresponding spectra obtained from the Monte Carlo full phase space simulations. Our fitted energy spectra are in good agreement with the Monte Carlo simulated spectra in terms of peak location, peak width, amplitude and smoothness of the spectrum. In addition, the derived depth dose curves of head-generated photons agree well in both shape and amplitude with those calculated using the full phase space data. The central axis depth dose curves and dose profiles at various depths have been compared using an automated electron beam commissioning procedure. The comparison has demonstrated that our method is capable of deriving the energy spectra for the Varian accelerator electron beams investigated. We have implemented this method in the electron beam commissioning procedure for Monte Carlo electron beam dose calculations. (author)

  12. Differences among doses for neuro-axis radiotherapy planning in the gonadal region

    International Nuclear Information System (INIS)

    Lima, F.F de; Vilela, E.C.; Oliveira, F.L.; Filho, J.A.

    2015-01-01

    Radiotherapy can disrupt the functioning of the hypothalamic-pituitary axis, directly causing ovarian deficiencies, such as the decrease in fertility or damage that renders the uterus incapable of accommodating the growth of a fetus. However, these issues have become increasingly important to a growing number of pediatric and adolescent cancer survivors. The whole-body, cranial-spinal axis, as well as abdomen and pelvic region irradiations may expose the ovaries to radiation and may cause premature ovarian failure, whereas doses above 35 Gy cranial can affect the hypothalamic-pituitary functions. This study performed a comparison of four doses of radiotherapy planning techniques for the neural axis. For this analysis, technical simulations were performed for the treatment of medulloblastoma in four different planning, applied in a RANDO anthropomorphic phantom and dosimeters (TLD-100). The radiation fields in the 1”st and 2”nd planning were 40 x 5 cm”2 and 17 x 5 cm”2 with 4.0 cm depth, in which doses were 0.03 and 0.05 Gy / day and 0.11 and 0.09 Gy / days, on the right and left sides, respectively. The 3”rd and 4”th measured planning 32 x 7 cm”2 and 18 x 7 cm”2, with a 2 cm gap and a 4.0 and 5.0 cm depth, in which doses were 1.08 and 0.2 Gy/day and 1.14 and 0.14 Gy/day, on the left and right sides, respectively. It could be observed that the doses in the ovaries in the 3”rd and 4”th schedules proved to be larger than the doses in the 1 s t and 2 n d planning. This is caused by the spinal field width and the depth of the second spinal field, which is 1.0 cm more than the field of the 1”st and 2”nd planning. These differences should be observed in image planning, as incorrect measures can cause damage in the treatment finish. (authors)

  13. Implementation of an algorithm for absorbed dose calculation in high energy photon beams at off axis points

    International Nuclear Information System (INIS)

    Matos, M.F.; Alvarez, G.D.; Sanz, D.E.

    2008-01-01

    Full text: A semiempirical algorithm for absorbed dose calculation at off-axis points in irregular beams was implemented. It is well known that semiempirical methods are very useful because of their easy implementation and its helpfulness in dose calculation in the clinic. These methods can be used as independent tools for dosimetric calculation in many applications of quality assurance. However, the applicability of such methods has some limitations, even in homogeneous media, specially at off axis points, near beam fringes or outside the beam. Only methods derived from tissue-air-ratio (TAR) or scatter-maximum-ratio (SMR) have been devised for those situations, many years ago. Despite there have been improvements for these manual methods, like the Sc-Sp ones, no attempt has been made to extend their usage at off axis points. In this work, a semiempirical formalism was introduced, based on the works of Venselaar et al. (1999) and Sanz et al. (2004), aimed to the Sc-Sp separation. This new formalism relies on the separation of primary and secondary components of the beam although in a relative way. The data required by the algorithm are reduced to a minimal, allowing for experimental easy. According to modern recommendations, reference measurements in water phantom are performed at 10 cm depth, keeping away electron contamination. Air measurements are done using a mini phantom instead of the old equilibrium caps. Finally, the calculation at off-axis points are done using data measured on the central beam axis; but correcting the results with the introduction of a measured function which depends on the location of the off axis point. The measurements for testing the algorithm were performed in our Siemens MXE linear accelerator. The algorithm was used to determine specific dose profiles for a great number of different beam configurations, and the results were compared with direct measurements to validate the accuracy of the algorithm. Additionally, the results were

  14. Radiation dose distributions close to the shower axis calculated for high energy electron initiated electromagnetic showers in air

    International Nuclear Information System (INIS)

    Geer, S.; Gsponer, A.

    1983-01-01

    Absorbed radiation doses produced by 500, 1,000 and 10,000 MeV electron initiated electromagnetic showers in air have been calculated using a Monte Carlo program. The radial distributions of the absorbed dose near to the shower axis are found to be significantly narrower than predicted by simple analytical shower theory. For a 500 MeV, 10 kA, 100 ns electron beam pulse, the region in which the total dose is in excess of 1 krad and the dose rate in excess of 10 10 rad/s is a cigar-shaped envelope of radius 1 m and length 200 m. (orig.) [de

  15. Effective dose from direct and indirect digital panoramic units

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Gun Sun; Kim, Jin Soo; Seo, Yo Seob; Kim, Jae Duk [School of Dentistry, Oral Biology Research Institute, Chosun University, Gwangju (Korea, Republic of)

    2013-06-15

    This study aimed to provide comparative measurements of the effective dose from direct and indirect digital panoramic units according to phantoms and exposure parameters. Dose measurements were carried out using a head phantom representing an average man (175 cm tall, 73.5 kg male) and a limbless whole body phantom representing an average woman (155 cm tall, 50 kg female). Lithium fluoride thermoluminescent dosimeter (TLD) chips were used for the dosimeter. Two direct and 2 indirect digital panoramic units were evaluated in this study. Effective doses were derived using 2007 International Commission on Radiological Protection (ICRP) recommendations. The effective doses of the 4 digital panoramic units ranged between 8.9 {mu}Sv and 37.8 {mu}Sv. By using the head phantom, the effective doses from the direct digital panoramic units (37.8 {mu}Sv, 27.6 {mu}Sv) were higher than those from the indirect units (8.9 {mu}Sv, 15.9 {mu}Sv). The same panoramic unit showed the difference in effective doses according to the gender of the phantom, numbers and locations of TLDs, and kVp. To reasonably assess the radiation risk from various dental radiographic units, the effective doses should be obtained with the same numbers and locations of TLDs, and with standard hospital exposure. After that, it is necessary to survey the effective doses from various dental radiographic units according to the gender with the corresponding phantom.

  16. Intensity-modulated radiotherapy for nasopharyngeal carcinoma: Clinical correlation of dose to the pharyngo-esophageal axis and dysphagia

    International Nuclear Information System (INIS)

    Fua, Tsien F.; Corry, June; Milner, Alvin D.; Cramb, Jim; Walsham, Sue F.; Peters, Lester J.

    2007-01-01

    Purpose: The aim of this study was to quantify the dose delivered to the pharyngo-esophageal axis using different intensity-modulated radiation therapy (IMRT) techniques for treatment of nasopharyngeal carcinoma and to correlate this with acute swallowing toxicity. Methods and Materials: The study population consisted of 28 patients treated with IMRT between February 2002 and August 2005: 20 with whole field IMRT (WF-IMRT) and 8 with IMRT fields junctioned with an anterior neck field with central shielding (j-IMRT). Dose to the pharyngo-esophageal axis was measured using dose-volume histograms. Acute swallowing toxicity was assessed by review of dysphagia grade during treatment and enteral feeding requirements. Results: The mean pharyngo-esophageal dose was 55.2 Gy in the WF-IMRT group and 27.2 Gy in the j-IMRT group, p < 0.001. Ninety-five percent (19/20) of the WF-IMRT group developed Grade 3 dysphagia compared with 62.5% (5/8) of the j-IMRT group, p = 0.06. Feeding tube duration was a median of 38 days for the WF-IMRT group compared with 6 days for the j-IMRT group, p = 0.04. Conclusions: Clinical vigilance must be maintained when introducing new technology to ensure that unanticipated adverse effects do not result. Although newer planning systems can reduce the dose to the pharyngo-esophageal axis with WF-IMRT, the j-IMRT technique is preferred at least in patients with no gross disease in the lower neck

  17. Off-axis dose equivalent due to secondary neutrons from uniform scanning proton beams during proton radiotherapy

    Science.gov (United States)

    Islam, M. R.; Collums, T. L.; Zheng, Y.; Monson, J.; Benton, E. R.

    2013-11-01

    The production of secondary neutrons is an undesirable byproduct of proton therapy and it is important to quantify the contribution from secondary neutrons to patient dose received outside the treatment volume. The purpose of this study is to investigate the off-axis dose equivalent from secondary neutrons experimentally using CR-39 plastic nuclear track detectors (PNTD) at ProCure Proton Therapy Center, Oklahoma City, OK. In this experiment, we placed several layers of CR-39 PNTD laterally outside the treatment volume inside a phantom and in air at various depths and angles with respect to the primary beam axis. Three different proton beams with max energies of 78, 162 and 226 MeV and 4 cm modulation width, a 5 cm diameter brass aperture, and a small snout located 38 cm from isocenter were used for the entire experiment. Monte Carlo simulations were also performed based on the experimental setup using a simplified snout configuration and the FLUKA Monte Carlo radiation transport code. The measured ratio of secondary neutron dose equivalent to therapeutic primary proton dose (H/D) ranged from 0.3 ± 0.08 mSv Gy-1 for 78 MeV proton beam to 37.4 ± 2.42 mSv Gy-1 for 226 MeV proton beam. Both experiment and simulation showed a similar decreasing trend in dose equivalent with distance to the central axis and the magnitude varied by a factor of about 2 in most locations. H/D was found to increase as the energy of the primary proton beam increased and higher H/D was observed at 135° compared to 45° and 90°. The overall higher H/D in air indicates the predominance of external neutrons produced in the nozzle rather than inside the body.

  18. Off-axis dose equivalent due to secondary neutrons from uniform scanning proton beams during proton radiotherapy

    International Nuclear Information System (INIS)

    Islam, M R; Collums, T L; Monson, J; Benton, E R; Zheng, Y

    2013-01-01

    The production of secondary neutrons is an undesirable byproduct of proton therapy and it is important to quantify the contribution from secondary neutrons to patient dose received outside the treatment volume. The purpose of this study is to investigate the off-axis dose equivalent from secondary neutrons experimentally using CR-39 plastic nuclear track detectors (PNTD) at ProCure Proton Therapy Center, Oklahoma City, OK. In this experiment, we placed several layers of CR-39 PNTD laterally outside the treatment volume inside a phantom and in air at various depths and angles with respect to the primary beam axis. Three different proton beams with max energies of 78, 162 and 226 MeV and 4 cm modulation width, a 5 cm diameter brass aperture, and a small snout located 38 cm from isocenter were used for the entire experiment. Monte Carlo simulations were also performed based on the experimental setup using a simplified snout configuration and the FLUKA Monte Carlo radiation transport code. The measured ratio of secondary neutron dose equivalent to therapeutic primary proton dose (H/D) ranged from 0.3 ± 0.08 mSv Gy −1  for 78 MeV proton beam to 37.4 ± 2.42 mSv Gy −1  for 226 MeV proton beam. Both experiment and simulation showed a similar decreasing trend in dose equivalent with distance to the central axis and the magnitude varied by a factor of about 2 in most locations. H/D was found to increase as the energy of the primary proton beam increased and higher H/D was observed at 135° compared to 45° and 90°. The overall higher H/D in air indicates the predominance of external neutrons produced in the nozzle rather than inside the body. (paper)

  19. Central axis dose verification in patients treated with total body irradiation of photons using a Computed Radiography system

    International Nuclear Information System (INIS)

    Rubio Rivero, A.; Caballero Pinelo, R.; Gonzalez Perez, Y.

    2015-01-01

    To propose and evaluate a method for the central axis dose verification in patients treated with total body irradiation (TBI) of photons using images obtained through a Computed Radiography (CR) system. It was used the Computed Radiography (Fuji) portal imaging cassette readings and correlate with measured of absorbed dose in water using 10 x 10 irradiation fields with ionization chamber in the 60 Co equipment. The analytical and graphic expression is obtained through software 'Origin8', the TBI patient portal verification images were processed using software ImageJ, to obtain the patient dose. To validate the results, the absorbed dose in RW3 models was measured with ionization chamber with different thickness, simulating TBI real conditions. Finally it was performed a retrospective study over the last 4 years obtaining the patients absorbed dose based on the reading in the image and comparing with the planned dose. The analytical equation obtained permits estimate the absorbed dose using image pixel value and the dose measured with ionization chamber and correlated with patient clinical records. Those results are compared with reported evidence obtaining a difference less than 02%, the 3 methods were compared and the results are within 10%. (Author)

  20. Sample Based Unit Liter Dose Estimates

    International Nuclear Information System (INIS)

    JENSEN, L.

    2000-01-01

    The Tank Waste Characterization Program has taken many core samples, grab samples, and auger samples from the single-shell and double-shell tanks during the past 10 years. Consequently, the amount of sample data available has increased, both in terms of quantity of sample results and the number of tanks characterized. More and better data is available than when the current radiological and toxicological source terms used in the Basis for Interim Operation (BIO) (FDH 1999a) and the Final Safety Analysis Report (FSAR) (FDH 1999b) were developed. The Nuclear Safety and Licensing (NS and L) organization wants to use the new data to upgrade the radiological and toxicological source terms used in the BIO and FSAR. The NS and L organization requested assistance in producing a statistically based process for developing the source terms. This report describes the statistical techniques used and the assumptions made to support the development of a new radiological source term for liquid and solid wastes stored in single-shell and double-shell tanks. The results given in this report are a revision to similar results given in an earlier version of the document (Jensen and Wilmarth 1999). The main difference between the results in this document and the earlier version is that the dose conversion factors (DCF) for converting μCi/g or μCi/L to Sv/L (sieverts per liter) have changed. There are now two DCFs, one based on ICRP-68 and one based on ICW-71 (Brevick 2000)

  1. Evaluation of off-axis wedge correction factor using diode dosimeters for estimation of delivered dose in external radiotherapy

    International Nuclear Information System (INIS)

    Allahverdi, Mahmoud; Shirazi, Alireza; Geraily, Ghazale; Mohammadkarim, Alireza; Esfehani, Mahbod; Nedaie, Hasanali

    2012-01-01

    An in vivo dosimetry system, using p-type diode dosimeters, was characterized for clinical applications of treatment machines ranging in megavoltage energies. This paper investigates two different models of diodes for externally wedged beams and explains a new algorithm for the calculation of the target dose at various tissue depths in external radiotherapy. The values of off-axis wedge correction factors were determined at two different positions in the wedged (toward the thick and thin edges) and in the non-wedged directions on entrance and exit surfaces of a polystyrene phantom in 60 Co and 6 MV photon beams. Depth transmission was defined on the entrance and exit surfaces to obtain the off-axis wedge correction factor at any depth. As the sensitivity of the diodes depends on physical characteristics (field size, source-skin distance (SSD), thickness, backscatter), correction factors were applied to the diode reading when measuring conditions different from calibration situations. The results indicate that needful correction factors for 60 Co wedged photons are usually larger than those for 6 MV wedged photon beams. In vivo dosimetry performed with the proposed algorithms at externally wedged beams has negligible probable errors (less than 0.5%) and is a reliable method for patient dose control. (author)

  2. Evaluation of off-axis wedge correction factor using diode dosimeters for estimation of delivered dose in external radiotherapy

    Directory of Open Access Journals (Sweden)

    Mahmoud Allahverdi

    2012-01-01

    Full Text Available An in vivo dosimetry system, using p-type diode dosimeters, was characterized for clinical applications of treatment machines ranging in megavoltage energies. This paper investigates two different models of diodes for externally wedged beams and explains a new algorithm for the calculation of the target dose at various tissue depths in external radiotherapy. The values of off-axis wedge correction factors were determined at two different positions in the wedged (toward the thick and thin edges and in the non-wedged directions on entrance and exit surfaces of a polystyrene phantom in 60 Co and 6 MV photon beams. Depth transmission was defined on the entrance and exit surfaces to obtain the off-axis wedge correction factor at any depth. As the sensitivity of the diodes depends on physical characteristics [field size, source-skin distance (SSD, thickness, backscatter], correction factors were applied to the diode reading when measuring conditions different from calibration situations . The results indicate that needful correction factors for 60 Co wedged photons are usually larger than those for 6 MV wedged photon beams. In vivo dosimetry performed with the proposed algorithms at externally wedged beams has negligible probable errors (less than 0.5% and is a reliable method for patient dose control.

  3. Introduction to the new version of the standard DIN 6814, part 3 'dose magnitudes and dose units'

    Energy Technology Data Exchange (ETDEWEB)

    Harder, D

    1985-02-01

    The recent draft of the DIN standard on dose quantities and dose units is presented on original version and explained by the chairman of the Working Comittee Dosimetry. There are important modifications by the introduction of SI units, the new definitions of site dose and individual dose characteristic dose rate and dose rate constant, as well as by corrections of the notions ''secondary electron equilibrium'' and ''free in air''.

  4. Introduction: Issues Related to Dose Units and Damage Correlation

    International Nuclear Information System (INIS)

    Stoller, Roger E.

    2012-01-01

    The observable effects of irradiation on material properties are complex and each such property changed depends sensitively on a range of irradiation and material parameters. This works against development of a universal exposure parameter. The irradiation dose to the material (both ionizing and displacement dose) can be calculated with good accuracy as long as the relevant reaction cross sections are known and implemented in the codes used. This suggests that a focus on dose calculations is warranted. When assessing damage correlation parameters, it is important to determine the appropriate dose parameter first. Then a clear distinction between damage formation and damage accumulation needs to be kept in mind. The dose unit is most helpful for estimating the primary damage generation, e.g. how damage energy is used to estimate atomic displacements. However, damage accumulation requires longer times and involves kinetic and thermodynamic processes that cannot be accounted for in a dose or primary damage unit. The adequacy of the primary damage formulations can be assessed through their use in mean field reaction rate theory or kinetic Monte Carlo microstructural evolution models to predict damage accumulation. The results of these models can be directly compared with experimental observations. (author)

  5. Unit of measurement used and parent medication dosing errors.

    Science.gov (United States)

    Yin, H Shonna; Dreyer, Benard P; Ugboaja, Donna C; Sanchez, Dayana C; Paul, Ian M; Moreira, Hannah A; Rodriguez, Luis; Mendelsohn, Alan L

    2014-08-01

    Adopting the milliliter as the preferred unit of measurement has been suggested as a strategy to improve the clarity of medication instructions; teaspoon and tablespoon units may inadvertently endorse nonstandard kitchen spoon use. We examined the association between unit used and parent medication errors and whether nonstandard instruments mediate this relationship. Cross-sectional analysis of baseline data from a larger study of provider communication and medication errors. English- or Spanish-speaking parents (n = 287) whose children were prescribed liquid medications in 2 emergency departments were enrolled. Medication error defined as: error in knowledge of prescribed dose, error in observed dose measurement (compared to intended or prescribed dose); >20% deviation threshold for error. Multiple logistic regression performed adjusting for parent age, language, country, race/ethnicity, socioeconomic status, education, health literacy (Short Test of Functional Health Literacy in Adults); child age, chronic disease; site. Medication errors were common: 39.4% of parents made an error in measurement of the intended dose, 41.1% made an error in the prescribed dose. Furthermore, 16.7% used a nonstandard instrument. Compared with parents who used milliliter-only, parents who used teaspoon or tablespoon units had twice the odds of making an error with the intended (42.5% vs 27.6%, P = .02; adjusted odds ratio=2.3; 95% confidence interval, 1.2-4.4) and prescribed (45.1% vs 31.4%, P = .04; adjusted odds ratio=1.9; 95% confidence interval, 1.03-3.5) dose; associations greater for parents with low health literacy and non-English speakers. Nonstandard instrument use partially mediated teaspoon and tablespoon-associated measurement errors. Findings support a milliliter-only standard to reduce medication errors. Copyright © 2014 by the American Academy of Pediatrics.

  6. NPSAT1 MEMS 3-AXIS Rate Sensor Suite Performance, Characterization, and Flight Unit Acceptance Testing

    Science.gov (United States)

    2011-09-01

    magnetometer as the sensor, and the ACS controller. The magnetic control approach of NPSAT1 relies on favorable moments of inertia by optimum equipment...parallel with the HAAS rotational axis. To cancel the earth’s rotational effects, the turntable was tilted at -36.4° (accounts for the geocentric ...this initialization. 108 a. Gyro Bias Calibration from Three-Axis Magnetometer Measurements Reference [35] presents a real-time approach for gyro

  7. Radiation dose to neonates on a Special Care Baby Unit

    International Nuclear Information System (INIS)

    Faulkner, K.; Barry, J.L.; Smalley, P.

    1989-01-01

    The skin entrance dose to neonates on a special care baby unit was estimated from a knowledge of the technique factors, X-ray tube output and backscatter factors. Normalized organ dose data were employed to estimate radiation dose to a number of critical organs. Methods of reducing radiation dose to neonates were investigated. Initially, this involved changing the radiographic technique factors and introducing a lead rubber adjustable collimator, placed on top of the incubator, in addition to light beam diaphragms on the X-ray tube. These modifications to the examination technique appeared to reduce average entrance dose per radiograph from 92 μGy, to 58 μGy, a reduction of 37%. Later, a rare-earth film-screen combination was introduced to replace existing fast calcium tungstate screens. This enabled average entrance dose per radiograph to be reduced to 39 μGy, a further reduction of 33%. The mean radiation dose to a neonate is mainly determined by the number of radiographs. (author)

  8. Radiation dose to neonates on a Special Care Baby Unit

    Energy Technology Data Exchange (ETDEWEB)

    Faulkner, K.; Barry, J.L.; Smalley, P.

    1989-03-01

    The skin entrance dose to neonates on a special care baby unit was estimated from a knowledge of the technique factors, X-ray tube output and backscatter factors. Normalized organ dose data were employed to estimate radiation dose to a number of critical organs. Methods of reducing radiation dose to neonates were investigated. Initially, this involved changing the radiographic technique factors and introducing a lead rubber adjustable collimator, placed on top of the incubator, in addition to light beam diaphragms on the X-ray tube. These modifications to the examination technique appeared to reduce average entrance dose per radiograph from 92 ..mu..Gy, to 58 ..mu..Gy, a reduction of 37%. Later, a rare-earth film-screen combination was introduced to replace existing fast calcium tungstate screens. This enabled average entrance dose per radiograph to be reduced to 39 ..mu..Gy, a further reduction of 33%. The mean radiation dose to a neonate is mainly determined by the number of radiographs.

  9. Role of changes in functional status of hypothalamic-pituitary-adrenocortical axis in immunoenhancement after low dose radiation

    International Nuclear Information System (INIS)

    Liu Shuzheng; Zhao Yong; Han Zhenbo

    1994-01-01

    Whole-body irradiation (WBI) of mice with 75 mGy X-rays caused increase in 5-hydroxytryptamine (5HT) content of hypothalamus and decrease in serum adrenocorticotropic hormone (ACTH) and corticosterone (CS) level, accompanied with potentiation of immune functions, expressed as increased spontaneous incorporation of 3 H-TdR into thymocytes, augmented proliferative reaction of the splenocytes to Con A and increased production of interleukin-2 by the splenocytes. After intra hypothalamic injection of 5HT there occurred a lowering of serum ACTH level and enhancement of immune reactivity of the splenic and thymic lymphocytes. It is assumed that low dose radiation could influence the central 5-hydroxytryptaminergic neurons causing increase in hypothalamic 5HT content and this, in turn, decreases pituitary secretion of ACTH with a down-regulation of the adrenocortical function. This would partially release the tonic suppression normally exerted on the immune organs by the hypothalamic-pituitary-adrenocortical axis, thus leading to potentiation of immune functions. These neuroendocrine changes should be considered as an important factor in the analysis of the mechanism of immunoenhancement after WBI with low doses

  10. Model-based calculations of off-axis ratio of conic beams for a dedicated 6 MV radiosurgery unit

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J. N.; Ding, X.; Du, W.; Pino, R. [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Department of Radiation Oncology, Methodist Hospital, Houston, Texas 77030 (United States)

    2010-10-15

    Purpose: Because the small-radius photon beams shaped by cones in stereotactic radiosurgery (SRS) lack lateral electronic equilibrium and a detector's finite cross section, direct experimental measurement of dosimetric data for these beams can be subject to large uncertainties. As the dose calculation accuracy of a treatment planning system largely depends on how well the dosimetric data are measured during the machine's commissioning, there is a critical need for an independent method to validate measured results. Therefore, the authors studied the model-based calculation as an approach to validate measured off-axis ratios (OARs). Methods: The authors previously used a two-component analytical model to calculate central axis dose and associated dosimetric data (e.g., scatter factors and tissue-maximum ratio) in a water phantom and found excellent agreement between the calculated and the measured central axis doses for small 6 MV SRS conic beams. The model was based on that of Nizin and Mooij [''An approximation of central-axis absorbed dose in narrow photon beams,'' Med. Phys. 24, 1775-1780 (1997)] but was extended to account for apparent attenuation, spectral differences between broad and narrow beams, and the need for stricter scatter dose calculations for clinical beams. In this study, the authors applied Clarkson integration to this model to calculate OARs for conic beams. OARs were calculated for selected cones with radii from 0.2 to 1.0 cm. To allow comparisons, the authors also directly measured OARs using stereotactic diode (SFD), microchamber, and film dosimetry techniques. The calculated results were machine-specific and independent of direct measurement data for these beams. Results: For these conic beams, the calculated OARs were in excellent agreement with the data measured using an SFD. The discrepancies in radii and in 80%-20% penumbra were within 0.01 cm, respectively. Using SFD-measured OARs as the reference data, the

  11. Representation and preservation of the water-energy dose unit

    International Nuclear Information System (INIS)

    Roos, M.

    1992-01-01

    To represent the water-energy dose unit for high-energy photon and electron radiation, the chemical procedure was expanded into a fundamental measuring technique, and established as a primary normal measuring device of the Federal Republic of Germany. In addition, the water-energy calorimetric dosemeter, a definition measuring method, is being developed which seems to be destined for making a contribution, over the longer term, to reducing measuring uncertainties in dosimetry. (orig./DG) [de

  12. Dose surveys in two digital mammography units using DICOM headers

    International Nuclear Information System (INIS)

    Tsalafoutas, I.; Michalaki, C.; Papagiannopoulou, C.; Efstathopoulos, E.

    2012-01-01

    Background and objective: Digital mammography units store images in DICOM format. Thus, data regarding the acquisition parameters are available within DICOM headers, including among others, the anode/filter combination, tube potential and tube current exposure time product, compressed breast thickness, entrance surface air kerma (ESAK) and mean glandular dose (MGD). However, manual extraction of these data for the verification of the displayed values' accuracy and for dose survey purposes is time consuming. Our objective was to develop a method that enables the automation of such procedures. Materials and methods: Two hundred mammographic examinations (800 mammograms) performed in two digital units (GE, Essential) were recorded on CD-roms. Using appropriate software (DICOM Info Extractor) all dose related DICOM headers were extracted into a Microsoft Excel based spreadsheet, containing embedded algorithms for the calculation of ESAK and MGD according to Dance et al (Phys. Med. Biol. 45, 2000) methodology. Results: The ESAK and MGD values stored in the DICOM headers were compared with those calculated and in most cases were within ±10%. The basic difference among the two mammographic units is that, the older one calculates MGD assuming a breast composition 50% glandular-50% adipose tissue, while the newer one calculates the actual breast glandularity and stores this value in a DICOM header. The average MGD values were 1.21 mGy and 1.38 mGy, respectively. Conclusion: For the units studied, the ESAK and MGD values stored in DICOM headers are reliable. Utilizing tools for their automatic extraction provides an easy way to perform dose surveys. (authors)

  13. The AGE-RAGE axis in an Arab population: The United Arab Emirates Healthy Futures (UAEHFS pilot study

    Directory of Open Access Journals (Sweden)

    Claire K. Inman

    2017-12-01

    Full Text Available Aims: The transformation of the United Arab Emirates (UAE from a semi-nomadic to a high income society has been accompanied by increasing rates of obesity and Type 2 diabetes mellitus. We examined if the AGE-RAGE (receptor for advanced glycation endproducts axis is associated with obesity and diabetes mellitus in the pilot phase of the UAE Healthy Futures Study (UAEHFS. Methods: 517 Emirati subjects were enrolled and plasma/serum levels of AGE, carboxy methyl lysine (CML-AGE, soluble (sRAGE and endogenous secretory (esRAGE were measured along with weight, height, waist and hip circumference (WC/HC, blood pressure, HbA1c, Vitamin D levels and routine chemistries. The relationship between the AGE-RAGE axis and obesity and diabetes mellitus was tested using proportional odds models and linear regression. Results: After covariate adjustment, AGE levels were significantly associated with diabetes status. Levels of sRAGE and esRAGE were associated with BMI and levels of sRAGE were associated with WC/HC. Conclusions: The AGE-RAGE axis is associated with diabetes status and obesity in this Arab population. Prospective serial analysis of this axis may identify predictive biomarkers of obesity and cardiometabolic dysfunction in the UAEHFS. Keywords: Advanced glycation endproducts (AGEs, Receptor for AGE (RAGE, Cohort study, Diabetes mellitus, Obesity

  14. The AGE-RAGE axis in an Arab population: The United Arab Emirates Healthy Futures (UAEHFS) pilot study.

    Science.gov (United States)

    Inman, Claire K; Aljunaibi, Abdullah; Koh, Hyunwook; Abdulle, Abdishakur; Ali, Raghib; Alnaeemi, Abdullah; Al Zaabi, Eiman; Oumeziane, Naima; Al Bastaki, Marina; Al-Houqani, Mohammed; Al-Maskari, Fatma; Al Dhaheri, Ayesha; Shah, Syed M; Abdel Wareth, Laila; Al Mahmeed, Wael; Alsafar, Habiba; Al Anouti, Fatme; Al Hosani, Ayesha; Haji, Muna; Galani, Divya; O'Connor, Matthew J; Ahn, Jiyoung; Kirchhoff, Tomas; Sherman, Scott; Hayes, Richard B; Li, Huilin; Ramasamy, Ravichandran; Schmidt, Ann Marie

    2017-12-01

    The transformation of the United Arab Emirates (UAE) from a semi-nomadic to a high income society has been accompanied by increasing rates of obesity and Type 2 diabetes mellitus. We examined if the AGE-RAGE (receptor for advanced glycation endproducts) axis is associated with obesity and diabetes mellitus in the pilot phase of the UAE Healthy Futures Study (UAEHFS). 517 Emirati subjects were enrolled and plasma/serum levels of AGE, carboxy methyl lysine (CML)-AGE, soluble (s)RAGE and endogenous secretory (es)RAGE were measured along with weight, height, waist and hip circumference (WC/HC), blood pressure, HbA1c, Vitamin D levels and routine chemistries. The relationship between the AGE-RAGE axis and obesity and diabetes mellitus was tested using proportional odds models and linear regression. After covariate adjustment, AGE levels were significantly associated with diabetes status. Levels of sRAGE and esRAGE were associated with BMI and levels of sRAGE were associated with WC/HC. The AGE-RAGE axis is associated with diabetes status and obesity in this Arab population. Prospective serial analysis of this axis may identify predictive biomarkers of obesity and cardiometabolic dysfunction in the UAEHFS.

  15. Patient doses from CT examinations in the United Arab Emirates

    International Nuclear Information System (INIS)

    Janeczek, J.

    2006-01-01

    Full text of publication follows: The main goal of the study was to estimate effective patient doses from the 6 most common CT examinations for different types of CT scanners within the United Arab Emirates. The results were used to assess future trends in patient CT doses following rapid replacement of axial and single-slice spiral scanners by multi-slice scanners. At present all three types of scanner technology exist: axial, spiral and multi-slice with axial scanners being gradually replaced by multi-slice scanners as the medical infrastructure of the country is modernized. Altogether there are more than 30 CT scanners in the country with a population of 4 million. Out of these 11 scanners are 16-slice models with tube-current modulation system. The majority of larger United Arab Emirates hospitals have at least two CT scanners: a single slice and 4 or 16-slice scanner. The survey was carried out with data collection forms distributed to the majority of CT scanner users in the United Arab Emirates hospitals, both private and government. Effective doses for different examinations were calculated from T.L.D. measurements using an Alderson Rando phantom simulating an average size patient. Our results show that effective doses to patients initially increased with the introduction of 4-slice scanners. Multi-slice scanners with 16 and more slices have tube-current modulation system as a standard. It is routinely used by radiographers in almost all examinations resulting in patient dose reduction up to 40 % in certain examinations. Another factor affecting population dose is the increased number of patients examined using multi-slice scanners. In the United Arab Emirates there was an increase of more than 30 % in the annual number of patients examined using multi-slice scanners in comparison to single-slice scanners. This fact is attributed to the ease and speed of operation of multi-slice scanners. Rapid increase in number of CT examinations is of concern. Medical

  16. Radiation Dose to Newborns in Neonatal Intensive Care Units

    International Nuclear Information System (INIS)

    Bahreyni Toossi, M. T.; Malekzadeh, M.

    2012-01-01

    With the increase of X-ray use for medical diagnostic purposes, knowing the given doses is necessary in patients for comparison with reference levels. The concept of reference doses or diagnostic reference levels has been developed as a practical aid in the optimization of patient protection in diagnostic radiology. To assess the radiation doses to neonates from diagnostic radiography (chest and abdomen). This study has been carried out in the neonatal intensive care unit of a province in Iran. Entrance surface dose was measured directly with thermoluminescent dosimeters. The population included 195 neonates admitted for a diagnostic radiography, in eight NICUs of different hospital types. The mean entrance surface dose for chest and abdomen examinations were 76.3 μGy and 61.5 μGy, respectively. Diagnostic reference levels for neonate in NICUs of the province were 88 μGy for chest and 98 μGy for abdomen examinations that were slightly higher than other studies. Risk of death due to radiation cancer incidence of abdomens examination was equal to 1.88 × 10 -6 for male and 4.43 × 10 -6 for female. For chest X-ray, it was equal to 2.54 × 10 -6 for male and 1.17 × 10 -5 for female patients. Diagnostic reference levels for neonates in our province were slightly higher than values reported by other studies such as European national diagnostic reference levels and the NRPB reference dose. The main reason was related to using a high mAs and a low kVp applied in most departments and also a low focus film distance. Probably lack of collimation also affected some exams in the NICUs.

  17. Individual radiation doses from unit releases of long lived radionuclides

    International Nuclear Information System (INIS)

    Bergstroem, U.; Nordlinder, S.

    1990-04-01

    The turn-over in a standard biosphere of radionuclides, disposed in a repository for high level waste was studied from a dose point of view. A multi-compartment model with unit releases to the biosphere was designed and solved by the BIOPATH-code. The uncertainty in the results due to the uncertainty in input parameter values were examined for all nuclides with the PRISM-system. Adults and five year old children were exposed from 10 different exposure pathways originating from activity in well and lake water. The results given as total doses per year and Bq release (conversion factors) can be used in combination with leakage rates from the geosphere for safety analysis of a repository. The conversion factors obtained (arithmetic mean values), are given. (65 refs.) (authors)

  18. Comparison radiation dose of Z-axis automatic tube current modulation technique with fixed tube current multi-detector row CT scanning of lower extremity venography

    International Nuclear Information System (INIS)

    Yoo, Beong Gyu; Kweon, Dae Cheol; Lee, Jong Seok; Jang, Keun Jo; Jeon, Sang Hwan; Kim, Yong Soo

    2007-01-01

    Z-axis automatic tube current modulation technique automatically adjusts tube current based on size of body region scanned. The purpose of the current study was to compare noise, and radiation dose of Multi-Detector row CT (MDCT) of lower extremity performed with Z-axis modulation technique of automatic tube current modulation with manual selection fixed tube current. Fifty consecutive underwent MDCT venography of lower extremity with use of a MDCT scanner fixed tube current and Z-axis automatic tube current modulation technique (10, 11 and 12 HU noise index, 70∼450 mA). Scanning parameters included 120 kVp, 0.5 second gantry rotation time, 1.35:1 beam pitch, and 1 mm reconstructed section thickness. For each subject, images obtained with Z-axis modulation were compared with previous images obtained with fixed tube current (200, 250, 300 mA) and with other parameters identical. Images were compared for noise at five levels: iliac, femoral, popliteal, tibial, and peroneal vein of lower extremity. Tube current and gantry rotation time used for acquisitions at these levels were recorded. All CT examinations of study and control groups were diagnostically acceptable, though objective noise was significantly more with Z-axis automatic tube current modulation. Compared with fixed tube current, Z-axis modulation resulted in reduction of CTDIvol (range, -6.5%∼-35.6%) and DLP (range,-0.2%∼-20.2%). Compared with manually selected fixed tube current, Z-axis automatic tube current modulation resulted in reduced radiation dose at MDCT of lower extremity venography

  19. Development of radiological concentrations and unit liter doses for TWRS FSAR radiological consequence calculations

    International Nuclear Information System (INIS)

    Cowley, W.L.

    1996-01-01

    The analysis described in this report develops the Unit Liter Doses for use in the TWRS FSAR. The Unit Liter Doses provide a practical way to calculate conservative radiological consequences for a variety of potential accidents for the tank farms

  20. Development and Assessment of Planetary Gear Unit for Experimental Prototype of Vertical Axis Wind Turbine

    Directory of Open Access Journals (Sweden)

    Urbahs A.

    2017-10-01

    Full Text Available The theoretical calculation for development of planetary gear unit of wind turbine (WT and its experimental tests are presented in the paper. Development of experimental prototypes from composite materials is essential to determine capability of element and its impact on feature. Two experimental scale prototypes of planetary gear unit for WT were developed for such purposes. Hall transducer, servomechanisms and optical tachometers were used to obtain results, comparison analysis of theoretical and actual data was performed as well as quality assessment of experimental prototypes of planetary gear unit. After kinematic and load analysis as well as control of rotation frequency, it is possible to declare that the unit is able to operate at designated quality. Theoretical calculations and test results obtained are used for industrial WT prototype development.

  1. Development and Assessment of Planetary Gear Unit for Experimental Prototype of Vertical Axis Wind Turbine

    Science.gov (United States)

    Urbahs, A.; Urbaha, M.; Carjova, K.

    2017-10-01

    The theoretical calculation for development of planetary gear unit of wind turbine (WT) and its experimental tests are presented in the paper. Development of experimental prototypes from composite materials is essential to determine capability of element and its impact on feature. Two experimental scale prototypes of planetary gear unit for WT were developed for such purposes. Hall transducer, servomechanisms and optical tachometers were used to obtain results, comparison analysis of theoretical and actual data was performed as well as quality assessment of experimental prototypes of planetary gear unit. After kinematic and load analysis as well as control of rotation frequency, it is possible to declare that the unit is able to operate at designated quality. Theoretical calculations and test results obtained are used for industrial WT prototype development.

  2. Novel high accurate sensorless dual-axis solar tracking system controlled by maximum power point tracking unit of photovoltaic systems

    International Nuclear Information System (INIS)

    Fathabadi, Hassan

    2016-01-01

    Highlights: • Novel high accurate sensorless dual-axis solar tracker. • It has the advantages of both sensor based and sensorless solar trackers. • It does not have the disadvantages of sensor based and sensorless solar trackers. • Tracking error of only 0.11° that is less than the tracking errors of others. • An increase of 28.8–43.6% depending on the seasons in the energy efficiency. - Abstract: In this study, a novel high accurate sensorless dual-axis solar tracker controlled by the maximum power point tracking unit available in almost all photovoltaic systems is proposed. The maximum power point tracking controller continuously calculates the maximum output power of the photovoltaic module/panel/array, and uses the altitude and azimuth angles deviations to track the sun direction where the greatest value of the maximum output power is extracted. Unlike all other sensorless solar trackers, the proposed solar tracking system is a closed loop system which means it uses the actual direction of the sun at any time to track the sun direction, and this is the contribution of this work. The proposed solar tracker has the advantages of both sensor based and sensorless dual-axis solar trackers, but it does not have their disadvantages. Other sensorless solar trackers all are open loop, i.e., they use offline estimated data about the sun path in the sky obtained from solar map equations, so low exactness, cloudy sky, and requiring new data for new location are their problems. A photovoltaic system has been built, and it is experimentally verified that the proposed solar tracking system tracks the sun direction with the tracking error of 0.11° which is less than the tracking errors of other both sensor based and sensorless solar trackers. An increase of 28.8–43.6% depending on the seasons in the energy efficiency is the main advantage of utilizing the proposed solar tracking system.

  3. Dose dependence of tensoresistance for the symmetrical orientation of the deformation axis relatively to all isoenergetic ellipsoids in γ-irradiated (60Co n-Si crystals

    Directory of Open Access Journals (Sweden)

    G.P. Gaidar

    2018-03-01

    Full Text Available The dose dependence of tensoresistance X /0, which was measured at the symmetrical orientation of the deformation axis (compression relatively to all isoenergetic ellipsoids both in the initial and in -irradiated samples, was investigated in n-Si crystals. It has been shown that changing the irradiation doses is accompanied by not only quantitative but also qualitative changes in the functional dependence X /0 = f (Х. Features of tensoresistance in n-Si irradiated samples were found depending on three crystallographic directions, along which the samples were cut out and the mechanical stress Х was applied.

  4. Quality control of radiopharmaceutical dose calibrators in nuclear medicine unit

    International Nuclear Information System (INIS)

    Oliveira, C.F.M.; Lucindo Junior, C.R.; Lopes Filho, F.J.

    2015-01-01

    As part of the program to ensure quality in nuclear medicine unit, in addition to diagnostic procedures, are evaluated activity meters, which is intended to measure the aliquot of radiation of radionuclides and / or radiopharmaceuticals that are administered to patients undergoing diagnostic investigation and / or therapeutic treatment. The good operating condition of dose calibrators is essential to ensure efficiency, safety and reliability of the measurements, once the lack of accuracy in the responses of these equipments can cause significant errors in the activity administered to the patient and may result in poor quality images resulting in the repetition of examis and interference in the successful treatment of the patient. This study aims to, considering the need for constant evaluation of the functioning of the activity meters and the fact that this issue be part the responsibilities of the professional of radiology, perform quality control testing of these instruments in relation to the most recent norm of National Commission of nuclear Energy (CNEN-NN 3:05) in Brazil, that is also in according to the international standards and reference values established during acceptance testing of these instruments in a nuclear medicine service. For this, was made a review of specific literature and the use of barium, cobalt and cesium to the tests in a nuclear medicine service of the state of Pernambuco in Brazil. The obtained results of the specific tests utilized to verify the correct working of the dose calibrators show coherency with the resolutions of the CNEN-NN 3:05 and are also in agreement with the international standards to that the measurement of activities be made with accurate results and thereby contribute to the proper functioning of nuclear medicine service. (authors)

  5. Improvement of off-axis SABR plan verification results by using adapted dose reconstruction algorithms for the Octavius 4D system.

    Science.gov (United States)

    Jeevanandam, Prakash; Agnew, Christina E; Irvine, Denise M; McGarry, Conor K

    2018-04-01

    Stereotactic ablative body radiotherapy (SABR) for lung patients can be performed with volumetric-modulated arc therapy (VMAT) plans using off-axis target geometry to allow treatment in their CBCT verified position. For patient-specific quality assurance measurements using the PTW Octavius 4D phantom (PTW, Freiburg, Germany) (OCT4D) in conjunction with an Octavius 1000SRS array (OCT1000) (PTW, Freiburg, Germany), repositioning the phantom off-axis is required to ensure the measurement area coincides with the tumor. The aim of this work is to quantify delivery errors using an array repositioned off-axis and evaluate new software which incorporates corrections for off-axis phantom measurements. Dynamic conformal arcs and 25 lung SABR plans were created with the isocenter at the patient midline and the target volume off-axis. Measurements were acquired with an OCT4D phantom in conjunction with a 729 array (PTW, Freiburg, Germany) (OCT729) placed at isocenter. These plans were recalculated and delivered to both the OCT729 and OCT1000 arrays repositioned so that the high-dose region was at the center of the phantom. Comparisons were made using VeriSoft v7.0 (PTW, Freiburg, Germany) and the newly implemented version 7.1 with 2%/2 mm gamma criterion (10% threshold) and results correlated with off-axis distance to the tumor. Average pass rates for VeriSoft v7.0 significantly reduced from 92.7 ± 2.4% to 84.9 ± 4.1% when the phantom was repositioned compared to the isocenter setup for the OCT729. The gamma pass rates significantly decreased the further the phantom was moved off-axis. Significantly higher pass rates were observed for the OCT1000 of 95.7 ± 3.6% and a significant decrease in gamma pass rate with off-axis phantom distance was again observed. In contrast, even with phantom repositioning, the pass rates for analysis with VeriSoft v7.1 were 93.7 ± 2.1% and 99.4 ± 1.1% for OCT729 and OCT1000, respectively. No significant difference in gamma pass rate

  6. Terms and definitions in the field of radiological technique. Dose quantities and units

    International Nuclear Information System (INIS)

    1985-12-01

    The standard gives the terms and definitions of concepts, dose quantities and units. The radiation field condition 'secondary electron equilibrium', which forms part of the definition of standard ion dose, is given more precisely. The term 'free in air' is used in its original meaning, i.e. characterization of measuring conditions excluding avoidable stray radiation, which deviates from DIN 6814, part 3/06.72. Dosemeters for measurement of standard ion dose of air kerma are calibrated 'free in air', but this calibration condition is not part of the quantity definition. The quantities standard ion dose or air kerma therefore can also be measured in any other material. The qunatitative relationships between standard ion dose and the quantities 'exposure' and air kerma, as given in the ICRU publication 33 'Quantities and Units' (1980), are explained. The standard introduces the SI units Gray (for energy dose), Sievert (for dose equivalent), and Becquerel (for the activity of a radioactive substance). As the change to the SI units conceals the approximated equality of the numerical values of the standrd ion dose of photon radiation in roentgen, of the energy dose for soft tissue in rad, and of the dose equivalent in rem, new definitions are given in accordance with ICRU 33 for the quantities specified dose rate, dose rate constant, and area exposure product. These definitions use the terms 'energy dose' and 'kerma'. The dose concepts applied in the field of radiation protection, especially ambient dose and individual dose, are defined as dose equivalents in compliance with the Radiation Protection Ordinance. The relevant sections present information on the conversion of standard ion dose values to the corresponding values of kerma, energy dose, or dose equivalent. (orig./HP) [de

  7. Monte Carlo based investigations of electron contamination from telecobalt unit head in build up region and its impact on surface dose.

    Science.gov (United States)

    Jagtap, A S; Palani Selvam, T; Patil, B J; Chavan, S T; Pethe, S N; Kulkarni, Gauri; Dahiwale, S S; Bhoraskar, V N; Dhole, S D

    2016-12-01

    A Telecobalt unit has wide range of applications in cancer treatments and is used widely in many countries all around the world. Estimation of surface dose in Cobalt-60 teletherapy machine becomes important since clinically useful photon beam consist of contaminated electrons during the patient treatment. EGSnrc along with the BEAMnrc user code was used to model the Theratron 780E telecobalt unit. Central axis depth dose profiles including surface doses have been estimated for the field sizes of 0×0, 6×6, 10×10, 15×15, 20×20, 25×25, 30×30cm 2 and at Source-to-surface distance (SSD) of 60 and 80cm. Surface dose was measured experimentally by the Gafchromic RTQA2 films and are in good agreement with the simulation results. The central axis depth dose data are compared with the data available from the British Journal of Radiology report no. 25. Contribution of contaminated electrons has also been calculated using Monte Carlo simulation by the different parts of the Cobalt-60 head for different field size and SSD's. Moreover, depth dose curve in zero area field size is calculated by extrapolation method and compared with the already published data. They are found in good agreement. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Control of absorbed dose in radiotherapy with 60 Co units

    International Nuclear Information System (INIS)

    Penchev, V.; Constantinov, B.; Buchakliev, Z.

    2000-01-01

    A Network for External Quality Audit has been developed and established in Bulgaria by the Secondary Standard Dosimetry Laboratory (SSDL) - Sofia. The results prove the usefulness of the TL Postal Dose programme in helping Bulgarian radiotherapy departments improve and maintain the consistency of patient doses in clinically acceptable level. The participation of the SSDL-Sofia in the IAEA Quality Audit Programme confirms the quite satisfactory accuracy of the therapy level dose measurements and determination achieved. The role of the SSDL is critical in providing traceable calibration to hospitals

  9. Dosimetric accuracy at low monitor unit setting in electron beams at different dose rates

    International Nuclear Information System (INIS)

    Ravikumar, M.; Ravichandran, R.; Supe, Sanjay S.; Sharma, Anil K.

    1999-01-01

    As electron beam with low monitor unit (LMU) settings are used in some dosimetric studies, better understanding of accuracy in dose delivery at LMU setting is necessary. The dose measurements were carried out with 0.6 cm 3 farmer type ion chamber at d max in a polystyrene phantom. Measurements at different MUs show that the dose linearity ratio (DLR) increases as the MU setting decreases below 20 MU and DLRs are found to increase when the incident electron beams have higher energies. The increase in DLR is minimum for low dose rate setting for all five electron beam energies (6, 9, 12, 16 and 20 MeV). As the variation in dose delivery is machine-specific, a detailed study should be conducted before the low MU setting is implemented. Since errors in dose delivery are high at higher dose rates, low dose rate may be better at low MU unit setting. (author)

  10. Dental radiographic units - radiation safety and patient doses

    International Nuclear Information System (INIS)

    Nagpal, J.S.; Varadharajan, Geetha

    2001-01-01

    Three models of dental radiographic machines have been examined for radiation safety. Using TL dosemeters, doses received by the patients at chest level and the gonads have been estimated. Care should be taken to shield gonads during dental radiographic examinations. (author)

  11. An overview of the United States dose reassessment program

    International Nuclear Information System (INIS)

    Christy, R.F.

    1983-01-01

    The US Dose Reassessment Program consists of a number of separate efforts to reexamine all the stages from the initial assembly of the fissionable material, through the transport of neutrons and gamma rays, to the final deposition of the dose of ionizing radiation. Where possible, experimental measurements will be used to normalize the calculations. This program is summarized as follows: (1) calculations on the output of prompt neutrons and gamma rays from the detonating bomb, by Los Alamos National Laboratory (LANL), including calculation of the output of various test bombs where measurements have been made and of a critical assembly of a Hiroshima type bomb, (2) transport calculations for prompt neutrons and gamma rays in air by Oak Ridge National Laboratory (ORNL) and Lawrence Livermore National Laboratory (LLNL) including transport in air of gamma rays secondary to prompt neutrons and calculation of various test devices, (3) calculation of the emission and transport in air of delayed gamma rays from the cloud of fission products by Science Applications, Inc. (SAI) which can also include delayed neutron calculations, (4) calculations of the shielding effects of buildings, etc., on the neutron and gamma ray flux by SAI and ORNL, (5) calculation of organ doses and transport in the body by ORNL and SAI, (6) calibration of in situ measurements by LLNL and ORNL, (7) thermoluminescent (TL) dosimetry to determine gamma ray flux by the Japanese National Institute of Radiological Sciences and the University of Utah, and (8) review of information on bomb yield by LANL and ORNL. (author)

  12. Comparative study of radiation dose between digital panoramic X-ray unit and general panoramic X-ray unit

    International Nuclear Information System (INIS)

    Li Qingshan; Duan Tao; Wang Xiaoyun; Zhao Li; Dong Jian; Wei Lei

    2010-01-01

    Objective: To compare the actual dose of patients who receive the same medical practice by either digital panoramic X-ray unit and general panoramic X-ray unit and give evidence for better selection of oral X-ray examination method. Methods: Round sheet lithium fluoride (LiF) thermoluminescent dosimeters (TLD) were used. The experiment was divided into natural background contrast group, general panoramic X-ray children group, general panoramic X-ray adults group, digital panoramic X-ray children group and digital panoramic X-ray adults group. The dosimeter of natural background radiation was placed at the office of the doctor, the dosimeters of general panoramic X-ray children group and general panoramic X-ray adults group were irradiated by different conditions according to the clinical application of panoramic X-ray to children and adults, the dosimeters of digital panoramic X-ray children group and digital panoramic X-ray adults group were irradiated by different conditions according to the clinical application of digital panoramic X-ray to children and adults. The thermoluminescent dosimeter was used to count and calculate the exposure doses in various groups. Results: The dose of children exposed in general panoramic X-ray unit was 1.28 times of that in digital panoramic X-ray unit, there was significant difference (t=6.904, P<0.01). The dose of adults exposed in general panoramic X-ray unit was 1.55 times of that in the digital panoramic X-ray unit, there also was significant difference (t=-11.514. P< 0.01). Conclusion: The digital panoramic X-ray unit can reduce the dose of patients, so the digital panoramic X-ray unit should be used as far as possible. (authors)

  13. Doses in sensitive organs during prostate treatment with a 60Co unit

    International Nuclear Information System (INIS)

    Vega-Carrillo, H.R.; Navarro Becerra, J.A.; Pérez Arrieta, M.L.; Pérez-Landeros, L.H.

    2014-01-01

    Using thermoluminiscent dosimeters the absorbed dose in the bladder, rectum and thyroid have been evaluated when 200 cGy was applied to the prostate. The treatment was applied with a 60 Co unit. A water phantom was built and thermoluminiscent dosimeters were located in the position where the prostate, bladder, rectum and thyroid are located. The therapeutic beam was applied in 4 irradiations at 0, 90, 180 and 270° with the prostate at the isocenter. The TLDs readouts were used to evaluate the absorbed dose in each organ. The absorbed doses were used to estimate the effective doses and the probability of developing secondary malignacies in thyroid, rectum and bladder. - Highlights: • The absorbed doses in the bladder, rectum and thyroid were measured. • Measurements were done during prostate treatment with a 60 Co unit. • TLD100s in a water phantom were used. • The effective doses were also estimated

  14. Arsenic-induced dose-dependent modulation of the NF-κB/IL-6 axis in thymocytes triggers differential immune responses

    International Nuclear Information System (INIS)

    Choudhury, Sreetama; Gupta, Payal; Ghosh, Sayan; Mukherjee, Sudeshna; Chakraborty, Priyanka; Chatterji, Urmi; Chattopadhyay, Sreya

    2016-01-01

    Highlights: • We for the first time explicitly show that arsenic exposure causes morphological damage to the thymus and results in heightened death of thymocytes. • Our data suggests that arsenic-induced apoptosis occurs due to increase in cellular oxidative and nitrosative stress. • We have for the first time established a non-classical role of NF-κB, correlating it with increase in FoxP3 expression. • The % of CD4+ CD25+ T cells were high and expression of FoxP3 has also increased at higher doses of arsenic indicating an nTreg bias. - Abstract: Arsenic contamination of drinking water is a matter of global concern. Arsenic intake impairs immune responses and leads to a variety of pathological conditions including cancer. In order to understand the intricate tuning of immune responses elicited by chronic exposure to arsenic, a mouse model was established by subjecting mice to different environmentally relevant concentrations of arsenic in drinking water for 30 days. Detailed study of the thymus, a primary immune organ, revealed arsenic-mediated tissue damage in both histological specimens and scanning electron micrographs. Analysis of molecular markers of apoptosis by Western blot revealed a dose-dependent activation of the apoptotic cascade. Enzymatic assays supported oxidative stress as an instigator of cell death. Interestingly, assessment of inflammatory responses revealed disparity in the NF-κB/IL-6/STAT3 axis, where it was found that in animals consuming higher amounts of arsenic NF-κB activation did not lead to the classical IL-6 upregulation response. This deviation from the canonical pathway was accompanied with a significant rise in numbers of CD4+ CD25+ FoxP3 expressing cells in the thymus. The cytokine profile of the animals exposed to higher doses of arsenic also indicated an immune-suppressed milieu, thus validating that arsenic shapes the immune environment in context to its dose of exposure and that at higher doses it leads to immune

  15. Modernization of the accident localisation system and relevant dose exposure on unit four of KNPP

    International Nuclear Information System (INIS)

    Valtchev, G.; Neshkova, M.; Nikilov, A.

    2005-01-01

    In 2001 a modernization of the accident localisation system (ALS) on Unit 4 was accomplished. The outage duration was longer then usually and special dose budget was elaborated. All ALS work was performed by external organisation. An ALARA implementation was recognised priority. The really accumulated collective doses were analysed and conclusions drawn. A short film on CD was prepared. (authors)

  16. Bioeffect modeling and equieffective dose concepts in radiation oncology – Terminology, quantities and units

    International Nuclear Information System (INIS)

    Bentzen, Søren M.; Dörr, Wolfgang; Gahbauer, Reinhard; Howell, Roger W.; Joiner, Michael C.; Jones, Bleddyn; Jones, Dan T.L.; Kogel, Albert J. van der; Wambersie, André; Whitmore, Gordon

    2012-01-01

    The International Commission on Radiation Units and Measurements (ICRU) Report Committee on “Bioeffect Modeling and Biologically Equivalent Dose Concepts in Radiation Therapy” is currently developing a comprehensive and consistent framework for radiobiological effect modeling based on the equieffective dose, EQDX α/β , a concept encompassing BED and EQD2 as special cases.

  17. Decommissioning of a 60Co unit and estimation of personal doses

    International Nuclear Information System (INIS)

    Lin, H.; Lin, P.; Liu, T.; Chu, C.

    2003-01-01

    Chang-hua Christian hospital needs to uninstall the 60 Co unit. The mode of this 60 Co teletherapy unit is SHIMADZU RTGS-10. The original lead head was taken as the source container of this 60 Co unit. The source head was dismantled and put into the prepared wooden box, after the source was sealed. This study describes the planning and dismantling of the retirement and transport of the 60 Co unit, and personal doses measured during the procedure. This work estimates the doses of radiation received by exposed workers during the dismantling of the machine. The workers received doses of approximately 53 μSv. This study shows that the original lead head can be used as the source container of this 60 Co unit. The 60 Co machine was smoothly dismantled and transported by conscientious and careful workers, using planned and controlled radiation protection, following the ALARA (as low as reasonably achievable) rule. (author)

  18. Variations of Patient Doses in Interventional Examinations at Different Angiographic Units

    International Nuclear Information System (INIS)

    Bor, Dogan; Toklu, Tuerkay; Olgar, Turan; Sancak, Tanzer; Cekirge, Saruhan; Onal, Baran; Bilgic, Sadik

    2006-01-01

    Purpose. We analyzed doses for various angiographic procedures using different X-ray systems in order to assess dose variations. Methods. Dose-area product (DAP), skin doses from thermoluminescent dosimeters and air kerma measurements of 308 patients (239 diagnostic and 69 interventional) were assessed for five different angiographic units. All fluoroscopic and radiographic exposure parameters were recorded online for single and multiprojection studies. Radiation outputs of each X-ray system were also measured for all the modes of exposure using standard protocols for such measurements. Results. In general, the complexity of the angiographic procedure was found to be the most important reason for high radiation doses. Skill of the radiologist, management of the exposure parameters and calibration of the system are the other factors to be considered. Lateral cerebral interventional studies carry the highest risk for deterministic effects on the lens of the eye. Effective doses were calculated from DAP measurements and maximum fatal cancer risk factors were found for carotid studies. Conclusions. Interventional radiologists should measure patient doses for their examinations. If there is a lack of necessary instrumentation for this purpose, then published dose reports should be used in order to predict the dose levels from some of the exposure parameters. Patient dose information should include not only the measured quantity but also the measured radiation output of the X-ray unit and exposure parameters used during radiographic and fluoroscopic exposures

  19. The high dose and low dose food irradiation programmes in the United States of America

    International Nuclear Information System (INIS)

    Brynjolfsson, A.

    1978-01-01

    Many highly acceptable shelf-stable irradiated food items have been developed in the United States of America. The most extensive wholesomeness studies ever carried out on any food-processing method continue to indicate that irradiated foods are wholesome. (author)

  20. Detection unit for measuring dose rate and/or dose of gamma radiation

    International Nuclear Information System (INIS)

    Viererbl, L.

    1987-01-01

    A detection unit is designed consisting of a scintillation detector of the NaI(Tl) type on which there is a correction filter. The filter is an aluminium case in which are placed alternately side by side lead and iron absorption layers. The sensitivity of the detector with this filter is constant for gamma energy within the range 50 to 1300 keV. (M.D.). 2 figs

  1. Monitor units are not predictive of neutron dose for high-energy IMRT

    Directory of Open Access Journals (Sweden)

    Hälg Roger A

    2012-08-01

    Full Text Available Abstract Background Due to the substantial increase in beam-on time of high energy intensity-modulated radiotherapy (>10 MV techniques to deliver the same target dose compared to conventional treatment techniques, an increased dose of scatter radiation, including neutrons, is delivered to the patient. As a consequence, an increase in second malignancies may be expected in the future with the application of intensity-modulated radiotherapy. It is commonly assumed that the neutron dose equivalent scales with the number of monitor units. Methods Measurements of neutron dose equivalent were performed for an open and an intensity-modulated field at four positions: inside and outside of the treatment field at 0.2 cm and 15 cm depth, respectively. Results It was shown that the neutron dose equivalent, which a patient receives during an intensity-modulated radiotherapy treatment, does not scale with the ratio of applied monitor units relative to an open field irradiation. Outside the treatment volume at larger depth 35% less neutron dose equivalent is delivered than expected. Conclusions The predicted increase of second cancer induction rates from intensity-modulated treatment techniques can be overestimated when the neutron dose is simply scaled with monitor units.

  2. Radiation doses in head CT examinations in Serbia: comparison among different CT units

    International Nuclear Information System (INIS)

    Arandjic, D.; Ciraj-Bjelac, O.; Bozovic, P.; Stankovic, J.; Hadnadjev, D.; Stojanovic, S.

    2012-01-01

    A rapid increase in number of Computed Tomography (CT) examinations has been observed world wide. As haed CT is the most frequent CT examination, the purpose of this study was to collect and analyse patient doses in children and adults in different CT units for this procedure. The study included 8 CT units from three manufacturers (Siemens, Toshiba and General Electric). Data for adults and pediatric patients were collected in terms of CTDIvol and DLP values. The doses were estimated as a mean value of 10 patients on each CT unit. For pediatrics, doses were collected for four age groups (0-1year, >1-5years, >5-10years and >10-15years). Comparing different manufacturers and the same number of detector rows it was observed that, in case of 16 slices units, doses were very similar on Siemens and General Electric scanner. CTDIvol and DLP on Siemens scanner were 60 mGy and 1066 mGy·cm, respectively, while on General Electric those values were 66 mGy and 1050 mGy·cm. However, this trend was not observed in case of 64 slices units. CTDIvol and DLP values collected on Toshiba were much higher (177 mGy and 2109 mGy·cm) than in case of Siemens scanner (59 mGy and 1060 mGy·cm). Doses on 16 and 64 slices Siemens scanners were very similar, while on 4 slices were higher. Except in two units, doses were were in line with DRLs. In case of pediatrics, doses increase with patient age and again Siemens scanner showed the lowest values while the highest were observed on Toshiba. (authors)

  3. Effect on moisture permeability of typewriting on unit dose package surfaces.

    Science.gov (United States)

    Rackson, J T; Zellhofer, M J; Birmingham, P H

    1984-10-01

    The effects of typewriting on labels of two unit dose packages with respect to moisture permeability were examined. Using an electric typewriter, a standard label format was imprinted on two different types of class A unit dose packages: (1) a heat-sealed paper-backed foil and cellofilm strip pouch, and (2) a copolyester and polyethylene multiple-cup blister with a heat-sealed paper-backed foil and cellofilm cover. The labels were typed at various typing-element impact settings. The official USP test for water permeation was then performed on typed packages and untyped control packages. The original untyped packages were confirmed to be USP class A quality. The packages for which successively harder impact settings were used showed a corresponding increase in moisture permeability. This resulted in a lowering of USP package ratings from class A to class B and D, some of which would be unsuitable for use in any unit dose system under current FDA repackaging standards. Typing directly onto the label of a unit dose package before it is sealed will most likely damage the package and possibly make it unfit for use. Pharmacists who must type labels for the unit dose packages studied should use the lowest possible typewriter impact setting and test for damage using the USP moisture-permeation test.

  4. Average glandular dose in routine mammography screening using a Sectra Microdose Mammography unit

    International Nuclear Information System (INIS)

    Hemdal, B.; Herrnsdorf, L.; Andersson, I.; Bengtsson, G.; Heddson, B.; Olsson, M.

    2005-01-01

    The Sectra MicroDose Mammography system is based on direct photon counting (with a solid-state detector), and a substantially lower dose to the breast than when using conventional system can be expected. In this work absorbed dose measurements have been performed for the first unit used in routine mammography screening (at the Hospitals of Helsingborg (Sweden)). Two European protocols on dosimetry in mammography have been followed. Measurement of half value layer (HVL) cannot be performed as prescribed, but this study has demonstrated than non-invasive measurements of HVL can be performed accurately with a sensitive and well collimated solid-state detector with simultaneous correction for the energy dependence. The average glandular dose for a 50 mm standard breast with 50% glandularity, simulated by 45 mm polymethylmethacrylate, was found to be 0.21 and 0.28 mGy in March and December 2004, respectively. These values are much lower than for any other mammography system on the market today. It has to be stressed that the measurement were made using the current clinical settings and that no systematic optimisation of the relationship between absorbed dose and diagnostic image quality has been performed within the present study. In order to further increase the accuracy of absorbed dose measurements for this unit, the existing dose protocols should be revised to account also for the tungsten/aluminium anode/filter combination, the multi-slit pre-collimator device and the occurrence of a dose profile in the scanning direction. (authors)

  5. Determination of Absorbed Dose to Water for Leksell Gamma Knife Unit

    International Nuclear Information System (INIS)

    Hrsak, H.

    2013-01-01

    Because of geometry of photon beams in Leksell Gamma Knife Unit (LGK), there are several technical problems in applying standard protocols for determination of absorbed dose to water (Dw). Currently, Dw in LGK unit, measured at the center of spherical plastic phantom, is used for dose calculation in LGK radiosurgery. Treatment planning software (LGP TPS) accepts this value as a measurement in water and since plastic phantom has higher electron density than water, this leads to systematic errors in dose calculation. To reduce these errors, a photon attenuation correction (PAC) method was applied. For that purpose, measurements of absorbed dose in a center of three different plastic phantoms with 16 cm diameter (ABS - acrylonitrile butadiene styrene, PMMA - polymethyl metacrylate, PMMA + teflon - polytetrafluoroethylene 5 mm shell) were made with ionization chamber (Semiflex, PTW Freiburg). For measured dose values, PAC to water was applied based on electron density (ED) and equivalent water depths (EWD) of the plastic phantoms. The relation between CT number and ED was determined by measuring CT number of standard CT to ED phantom (CIRS Model 062 Phantom). Absorbed dose in plastic phantoms was 2.5 % lower than calculated dose in water for ABS phantom and more than 5.5 % lower for PMMA and PMMA+teflon phantom. Calculated dose in water showed more consistent values for all three phantoms (max. difference 2.6 %). EWD for human cranial bones and brain has value close to the EWD of ABS phantom, which makes this phantom most suitable for dose measurements in clinical application. In LGK radiosurgery determination of errors related to the difference of phantom materials should not be neglected and measured dose should be corrected before usage for patient treatment dose calculation.(author)

  6. Answers to questions about updated estimates of occupational radiation doses at Three Mile Island, Unit 2

    International Nuclear Information System (INIS)

    1983-12-01

    The purpose of this question and answer report is to provide a clear, easy-to-understand explanation of revised radiation dose estimates which workers are likely to receive over the course of the cleanup at Three Mile Island, Unit 2, and of the possible health consequences to workers of these new estimates. We will focus primarily on occupational dose, although pertinent questions about public health and safety will also be answered

  7. TMI-2 [Three Mile Island Unit 2] reactor building dose reduction task force

    International Nuclear Information System (INIS)

    Daniels, R.S.

    1988-01-01

    In late October 1982, the director of Three Mile Island Unit 2 (TMI-2) created the dose reduction task force with the objective of identifying the principal radiological sources in the reactor building and recommending actions to minimize the dose to workers on labor-intensive projects. Members of the task force were drawn form various groups at TMI. Findings and recommendations were presented to the US Nuclear Regulatory Commission in a briefing on November 18, 1982. The task force developed a three-step approach toward dose reduction. Step 1 identified the radiological sources. Step 2 modeled the source and estimated its contribution to the general area dose rates. Step 3 recommended actions to achieve dose reductions consistent with general exposure rate goals

  8. Canadian and United States regulatory models compared: doses from atmospheric pathways

    International Nuclear Information System (INIS)

    Peterson, S-R.

    1997-01-01

    CANDU reactors sold offshore are licensed primarily to satisfy Canadian Regulations. For radioactive emissions during normal operation, the Canadian Standards Association's CAN/CSA-N288.1-M87 is used. This standard provides guidelines and methodologies for calculating a rate of radionuclide release that exposes a member of the public to the annual dose limit. To calculate doses from air concentrations, either CSA-N288.1 or the Regulatory Guide 1.109 of the United States Nuclear Regulatory Commission, which has already been used to license light-water reactors in these countries, may be used. When dose predictions from CSA-N288.1 are compared with those from the U.S. Regulatory Guides, the differences in projected doses raise questions about the predictions. This report explains differences between the two models for ingestion, inhalation, external and immersion doses

  9. Modernization of the accident localization system and relevant dose exposure on Unit 4 of KNPP

    Energy Technology Data Exchange (ETDEWEB)

    Valtchev, G.; Neshkova, A.; Nikolov, M. [Nuclear Power Plant Kozloduy, 3321 Kozloduy (Bulgaria)

    2004-07-01

    In 2001 a modernization of the Accident Localization System (ALS) on unit 4 was accomplished. The outage duration was longer then usually and special dose budget was elaborated. All ALS work was performed by external organization. An ALARA implementation was recognized priority. The really accumulated collective doses were analyzed and conclusions drawn. A short film on CD was prepared. Two conclusions are drawn: 1. Good work management and a first attempt of effective empowerment of the workers gave satisfactory results; 2. Although the work was not typical, and performed for a first time, the ALARA implementation reduced the projected collective dose with 19%.

  10. Dose rate evaluation of workers on the operation floor in Fukushima-Daiichi Unit 3

    Science.gov (United States)

    Matsushita, Kaoru; Kurosawa, Masahiko; Shirai, Keisuke; Matsuoka, Ippei; Mukaida, Naoki

    2017-09-01

    At Fukushima Daiichi Nuclear Power Plant Unit 3, installation of a fuel handling machine is planned to support the removal of spent fuel. The dose rates at the workplace were calculated based on the source distribution measured using a collimator in order to confirm that the dose rates on the operation floor were within a manageable range. It was confirmed that the accuracy of the source distribution was C/M = 1.0-2.4. These dose rates were then used to plan the work on the operation floor.

  11. Radiation doses received by premature babies in the neonatal intensive care unit

    International Nuclear Information System (INIS)

    Thierry-Chef, I.; Maccia, C.; Thierry-Chef, I.; Laurier, D.; Tirmarche, M.; Costil, J.

    2005-01-01

    Purpose. Because of frequent radiological investigations performed in 1 neonatal intensive care unit, a dosimetry study was carried out to assess the level of doses received by premature babies. Materials and methods. In vivo measurements were performed and effective doses were evaluated for single radiographs. Individual cumulative doses received over the period of stay were then estimated, for each premature baby entering the intensive care unit in 2002, taking into account the number of radiographs they underwent. Results. On average, babies stayed for a week and more than one radio-graph was taken per day. Results showed that, even if average doses per radiograph were relatively low (25μSv), cumulative doses strongly depended on the length of stay, and can reach a few mSv. Conclusion. Even if doses per radiograph are in agreement with European recommendations, optimisation of doses is particularly important because premature babies are more sensitive to radiation than adults and because they usually undergo further radiological examinations in other services. On the basis of the results of this dosimetry study, the implementation of a larger study is being discussed. (author)

  12. Cost-effectiveness of pharmacogenetic-guided dosing of warfarin in the United Kingdom and Sweden

    NARCIS (Netherlands)

    Verhoef, T. I.; Redekop, W. K.; Langenskiold, S.; Kamali, F.; Wadelius, M.; Burnside, G.; Maitland-van der Zee, A.-H.; Hughes, D. A.; Pirmohamed, M.

    2016-01-01

    We aimed to assess the cost-effectiveness of pharmacogenetic-guided dosing of warfarin in patients with atrial fibrillation (AF) in the United Kingdom and Sweden. Data from EU-PACT, a randomized controlled trial in newly diagnosed AF patients, were used to model the incremental costs per

  13. Radiation dose distribution monitoring at neutron radiography facility area, Nuclear Energy Unit, Malaysia

    International Nuclear Information System (INIS)

    Abdul Razak Daud

    1995-01-01

    One experiment was carried out to get the distribution of radiation doses at the neutron radiography facilities, Nuclear Energy Unit, Malaysia. The analysis was done to evaluate the safety level of the area. The analysis was used in neutron radiography work

  14. Comparison of 2-Dose and 3-Dose 9-Valent Human Papillomavirus Vaccine Schedules in the United States: A Cost-effectiveness Analysis.

    Science.gov (United States)

    Laprise, Jean-François; Markowitz, Lauri E; Chesson, Harrell W; Drolet, Mélanie; Brisson, Marc

    2016-09-01

    A recent clinical trial using the 9-valent human papillomavirus virus (HPV) vaccine has shown that antibody responses after 2 doses are noninferior to those after 3 doses, suggesting that 2 and 3 doses may have comparable vaccine efficacy. We used an individual-based transmission-dynamic model to compare the population-level effectiveness and cost-effectiveness of 2- and 3-dose schedules of 9-valent HPV vaccine in the United States. Our model predicts that if 2 doses of 9-valent vaccine protect for ≥20 years, the additional benefits of a 3-dose schedule are small as compared to those of 2-dose schedules, and 2-dose schedules are likely much more cost-efficient than 3-dose schedules. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  15. Dose per unit area - a study of elicitation of nickel allergy

    DEFF Research Database (Denmark)

    Fischer, Louise Arup; Menné, Torkil; Johansen, Jeanne Duus

    2007-01-01

    BACKGROUND: Experimental sensitization depends upon the amount of allergen per unit skin area and is largely independent of the area size. OBJECTIVES: This study aimed at testing if this also applies for elicitation of nickel allergy. PATIENTS/METHODS: 20 nickel allergic individuals were tested...... with a patch test and a repeated open application test (ROAT). Nickel was applied on small and large areas. The varying parameters were area, total dose and dose per unit area. RESULTS: In the patch test, at a low concentration [15 microg nickel (microg Ni)/cm(2)], there were significantly higher scores...... on the large area with the same dose per area as the small area. At higher concentrations of nickel, no significant differences were found. In the ROAT at low concentration (6.64 microg Ni/cm(2)), it was found that the latency period until a reaction appeared was significantly shorter on the large area...

  16. PWR design for low doses in the United Kingdom: The present and the future

    Energy Technology Data Exchange (ETDEWEB)

    Zodiates, A.M.; Willcock, A. [PWR Project Group, Knutsford, England (United Kingdom)

    1995-03-01

    The Pressurizer Water Reactor (PWR) design chosen for adoption by Nuclear Electric plc was based on the Westinghouse Standard Nuclear Unit Power Plant System (SNUPPS). This design was developed to meet the United Kingdom (UK) requirements and those improvements are embodied in the Sizewell B plant. Nuclear Electric plc is now looking to the design of the future PWRs to be built in the UK. These PWRs will be based as replicas of the Sizewell B design, but attention will be given to reducing operator doses further. This paper details the approach in operator protection improvements incorporated at Sizewall B, presents the estimated annual collective dose, and identifies the approach being adopted to reduce further operator doses in future plants.

  17. Blunting of the HPA-axis underlies the lack of preventive efficacy of early post-stressor single-dose Delta-9-tetrahydrocannabinol (THC).

    Science.gov (United States)

    Mayer, Tzur Alexander; Matar, Michael Alex; Kaplan, Zeev; Zohar, Joseph; Cohen, Hagit

    2014-07-01

    The therapeutic value of Delta-9-tetrahydrocannabinol (Δ9-THC) in the aftermath of trauma has recently raised interest. A prospective animal model for posttraumatic stress disorder was employed to assess the behavioral effects of a single dose of Δ9-THC administered intraperitoneally following exposure to psychogenic stress. Animals were exposed to predator scent stress and treated 1h later with Δ9-THC (1, 5 and 10mg/kg) or vehicle. The outcome measures included behavior in an elevated plus-maze and acoustic startle response 1, 6 and 24 h or 7 days after exposure and freezing behavior upon exposure to a trauma cue on day 8. Pre-set cut-off behavioral criteria classified exposed animals as those with "extreme," "minimal" or "intermediate" (partial) response. Circulating corticosterone levels were assessed over 2h after exposure with and without Δ9-THC. The behavioral effects of a CB1 antagonist (AM251) administered systemically 1h post exposure were evaluated. In the short term (1-6 h), 5 mg/kg of Δ9-THC effectively attenuated anxiety-like behaviors. In the longer-term (7 days), it showed no effect in attenuating PTSD-like behavioral stress responses, or freezing response to trauma cue. Δ9-THC significantly decreased corticosterone levels. In contrast, administration of AM251 (a CB1 antagonist/inverse agonist) 1 h post exposure attenuated long-term behavioral stress responses through activation of the HPA-axis. The demonstrated lack of preventive efficacy of early Δ9-THC treatment and reports of its anxiogenic effects in many individuals raises doubts not only regarding its potential clinical value, but also the advisability of clinical trials. The endocannabinoids exert complex effects on behavioral responses mediating glucocorticoid effects on memory of traumatic experiences. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Influence of source geometry and materials on the transverse axis dosimetry of 192Ir brachytherapy sources

    International Nuclear Information System (INIS)

    Wang, Ruqing; Sloboda, Ron S.

    1998-01-01

    Monte Carlo dose rates on the transverse axis in water and air kerma strengths normalized to unit source activity were calculated for a low dose rate steel-clad 192 Ir source, MicroSelectron high dose rate and pulsed dose rate 192 Ir sources, and a VariSource high dose rate 192 Ir source, as well as five other hypothetical cylindrical 192 Ir source designs. Based on these results, the dependence of dose rate and air kerma strength on source geometry and materials was analysed. Source geometry and attenuation in the core material are the important factors determining basic dosimetric characteristics. Core length, h, only affects the dose rate on the transverse axis at radial distances r 192 Ir sources is suggested, and similarities and differences in the dose rate constant and radial dose function between these sources are explained. (author)

  19. Dose linearity and monitor unit stability of a G4 type cyberknife robotic stereotactic radiosurgery system

    International Nuclear Information System (INIS)

    Sudahar, H.; Kurup, P.G.G.; Murali, V.; Velmurugan, J.

    2012-01-01

    Dose linearity studies on conventional linear accelerators show a linearity error at low monitor units (MUs). The purpose of this study was to establish the dose linearity and MU stability characteristics of a cyberknife (Accuracy Inc., USA) stereotactic radiosurgery system. Measurements were done at a depth of 5 cm in a stereotactic dose verification phantom with a source to surface distance of 75 cm in a Generation 4 (G4) type cyberknife system. All the 12 fixed-type collimators starting from 5 to 60 mm were used for the dose linearity study. The dose linearity was examined in small (1-10), medium (15-100) and large (125-1000) MU ranges. The MU stability test was performed with 60 mm collimator for 10 MU and 20 MU with different combinations. The maximum dose linearity error of -38.8% was observed for 1 MU with 5 mm collimator. Dose linearity error in the small MU range was considerably higher than in the medium and large MU ranges. The maximum error in the medium range was -2.4%. In the large MU range, the linearity error varied between -0.7% and 1.2%. The maximum deviation in the MU stability was -3.03%. (author)

  20. Dose in sensitive organs during the prostate treatment with a 60Co unit

    International Nuclear Information System (INIS)

    Vega C, H. R.; Navarro B, J. A.; Perez A, M. L.; Perez L, L. H.

    2012-10-01

    The absorbed dose by the bladder, the rectum and the gland thyroid was measured during a treatment applied for prostate cancer by means of a Cobalt 60 unit. The dose was measured using thermoluminescent dosimeters of the type TLD 100, with the values of the absorbed the values of the effective dose were calculated and was determined the probability of the development of a secondary cancer. Because these measurements cannot be made -in vivo- a phantom or mannequin was built with water that represents the hip and part of the torso of the human body and to represent the neck was used polyethylene. The study was carried out in the Instituto Zacatecano del Tumor that has a -cobalt bomb- which is used to treat oncology patients, during the phantom irradiation a dose of 200 c Gy was applied of this dose the bladder received 96.7%, the rectum 100.8% and the gland thyroid 0.3%. The dose received by the rectum and the bladder is due to the therapeutic beam while the dose received by the thyroid is due to the dispersed radiation by the phantom. The probability that in these organs a new neoplasm is developed is of 0.033% for the bladder, 0.157% for the rectum and 7.8 x 10 -5 % for the thyroid case. (Author)

  1. Independent dose per monitor unit review of eight U.S.A. proton treatment facilities

    International Nuclear Information System (INIS)

    Moyers, M. F.; Ibbott, G. S.; Grant, R. L.; Summers, P. A.; Followill, D. S.

    2014-01-01

    Purpose: Compare the dose per monitor unit at different proton treatment facilities using three different dosimetry methods. Methods: Measurements of dose per monitor unit were performed by a single group at eight facilities using 11 test beams and up to six different clinical portal treatment sites. These measurements were compared to the facility reported dose per monitor unit values. Results: Agreement between the measured and reported doses was similar using any of the three dosimetry methods. Use of the ICRU 59 N D,w based method gave results approximately 3% higher than both the ICRU 59 N X and ICRU 78 (TRS-398) N D,w based methods. Conclusions: Any single dosimetry method could be used for multi-institution trials with similar conformity between facilities. A multi-institutional trial could support facilities using both the ICRU 59 N X based and ICRU 78 (TRS-398) N D,w based methods but use of the ICRU 59 N D,w based method should not be allowed simultaneously with the other two until the difference is resolved

  2. Annual dose at the exclusion area boundary of a multi-unit CANDU site

    International Nuclear Information System (INIS)

    Gagnon, N.; Bobb, C.R.; Tsang, K.T.

    1997-01-01

    The annual dose to members of the public from CANDU nuclear power stations is dominated by the contribution from airborne effluents. The principal radionuclides contributing to the annual dose are tritium, carbon-14 and noble gases. The tritium is released as tritiated heavy-water vapour; the carbon-14 is released principally as carbon dioxide. To demonstrate compliance with the public dose limit, AECL has calculated the annual dose from airborne emissions from 10 CANDU units at an extended Wolsong site. The analysis has used the treatment of atmospheric dispersion described in the US Regulatory Guide 1.111 and programmed in the code XOQDOQ. The analysis has then modelled the transport of these airborne emissions through the environment as they expose the critical group using the US Regulatory Guide 1.109. the study takes account of the different annual emissions from each unit to reflect the different design features of the units. This study also includes a treatment of topography and makes allowances for building wake effects

  3. Applying graphics processor units to Monte Carlo dose calculation in radiation therapy

    Directory of Open Access Journals (Sweden)

    Bakhtiari M

    2010-01-01

    Full Text Available We investigate the potential in using of using a graphics processor unit (GPU for Monte-Carlo (MC-based radiation dose calculations. The percent depth dose (PDD of photons in a medium with known absorption and scattering coefficients is computed using a MC simulation running on both a standard CPU and a GPU. We demonstrate that the GPU′s capability for massive parallel processing provides a significant acceleration in the MC calculation, and offers a significant advantage for distributed stochastic simulations on a single computer. Harnessing this potential of GPUs will help in the early adoption of MC for routine planning in a clinical environment.

  4. Radiation doses to neonates and issues of radiation protection in a special care baby unit

    International Nuclear Information System (INIS)

    Armpilia, C.I.; Fife, I.A.J.; Croasdale, P.L.

    2001-01-01

    Radiographs are most commonly taken in the neonatal period to assist in the diagnosis and management of respiratory difficulties. Frequent accurate radiographic assessment is required and a knowledge of the radiation dose is necessary to make the justification of such exposures. A survey of radiation doses to neonates from diagnostic X-ray examinations (chest and abdomen) has been carried out in the special care baby unit (SCBU) of the Royal Free Hospital. Entrance surface dose (ESD) was calculated from Quality Control measurements on the X-ray set itself. Direct measurement of radiation doses was also performed using highly sensitive thermoluminescence dosimeters (LiF:Mg,Cu,P), calibrated and tested for consistency in sensitivity. The mean ESD per radiograph was calculated to be 36μGy (with a standard deviation of 6μGy), averaged over 95 X-ray examinations. The ESD's as derived from the TLD crystals, ranged from 18μGy to 60μGy. The mean energy imparted (EI) and the mean whole body dose per radiograph were estimated to be 14μJ and 10μGy respectively. Assuming that neonates and foetuses are equally susceptible to carcinogenic effects of radiation (it involves an overestimation of risk), the radiation risk of childhood cancer from a single radiograph was estimated to be of the order (0.3-1.3)x10 -6 . Radiation doses compared favourably with the reference value of 80μGy ESD published by CEC in 1996. (author)

  5. Estimation of North American population doses resulting from radon-222 release in western United States: methodology

    International Nuclear Information System (INIS)

    Fields, D.E.; Travis, C.C.; Watson, A.P.; McDowell-Boyer, L.M.

    1979-12-01

    The report represents a compilation of computer codes used to estimate potential human exposures and inhalation doses due to unit releases of 222 Rn from uranium milling sites in western United States. The populations considered for potential exposure to risk from 222 Rn and associated daughters are the inhabitants of North America between 20 0 and 60 0 North latitude. The primary function of these codes is to integrate spatially atmospheric radionuclide concentrations with current population data for the geographic area under consideration. It is expected that these codes will be of assistance to anyone interested in assessing nuclear or nonnuclear population exposures over large geographic areas

  6. X/Qs and unit dose calculations for Central Waste Complex interim safety basis effort

    International Nuclear Information System (INIS)

    Huang, C.H.

    1996-01-01

    The objective for this problem is to calculate the ground-level release dispersion factors (X/Q) and unit doses for onsite facility and offsite receptors at the site boundary and at Highway 240 for plume meander, building wake effect, plume rise, and the combined effect. The release location is at Central Waste Complex Building P4 in the 200 West Area. The onsite facility is located at Building P7. Acute ground level release 99.5 percentile dispersion factors (X/Q) were generated using the GXQ. The unit doses were calculated using the GENII code. The dimensions of Building P4 are 15 m in W x 24 m in L x 6 m in H

  7. A method for calculation of dose per unit concentration values for aquatic biota

    International Nuclear Information System (INIS)

    Batlle, J Vives i; Jones, S R; Gomez-Ros, J M

    2004-01-01

    A dose per unit concentration database has been generated for application to ecosystem assessments within the FASSET framework. Organisms are represented by ellipsoids of appropriate dimensions, and the proportion of radiation absorbed within the organisms is calculated using a numerical method implemented in a series of spreadsheet-based programs. Energy-dependent absorbed fraction functions have been derived for calculating the total dose per unit concentration of radionuclides present in biota or in the media they inhabit. All radionuclides and reference organism dimensions defined within FASSET for marine and freshwater ecosystems are included. The methodology has been validated against more complex dosimetric models and compared with human dosimetry based on ICRP 72. Ecosystem assessments for aquatic biota within the FASSET framework can now be performed simply, once radionuclide concentrations in target organisms are known, either directly or indirectly by deduction from radionuclide concentrations in the surrounding medium

  8. Design of shared unit-dose drug distribution network using multi-level particle swarm optimization.

    Science.gov (United States)

    Chen, Linjie; Monteiro, Thibaud; Wang, Tao; Marcon, Eric

    2018-03-01

    Unit-dose drug distribution systems provide optimal choices in terms of medication security and efficiency for organizing the drug-use process in large hospitals. As small hospitals have to share such automatic systems for economic reasons, the structure of their logistic organization becomes a very sensitive issue. In the research reported here, we develop a generalized multi-level optimization method - multi-level particle swarm optimization (MLPSO) - to design a shared unit-dose drug distribution network. Structurally, the problem studied can be considered as a type of capacitated location-routing problem (CLRP) with new constraints related to specific production planning. This kind of problem implies that a multi-level optimization should be performed in order to minimize logistic operating costs. Our results show that with the proposed algorithm, a more suitable modeling framework, as well as computational time savings and better optimization performance are obtained than that reported in the literature on this subject.

  9. Radiation doses and risks to neonates undergoing common radiographic examinations in the neonatal intensive care unit

    International Nuclear Information System (INIS)

    McParland, B.J.; Lee, R.

    1996-01-01

    Neonates in the-Neonatal Intensive Care Unit (NICU) can receive large numbers of radiographs owing to the clinical conditions they may present. More neonatal radiation dosimetry data are required for three fundamental reasons: (1.) to aid in the establishment of reference dose levels for interinstitutional comparisons; (2.) to improve childhood cancer risk estimates following neonatal exposure; and (3.) to indicate appropriate directions for dose reduction. This paper describes an investigation of two different NICU radiological techniques with significantly different neonate doses. While patient-matched images taken with both techniques were assessed in a blind review, this component of the study is beyond the scope of this paper and is not discussed here. (author)

  10. Neonatal doses from X ray examinations by birth weight in a neonatal intensive care unit

    Energy Technology Data Exchange (ETDEWEB)

    Ono, K.; Akahane, K.; Aota, T.; Hada, M.; Takano, Y.; Kai, M.; Kusama, T

    2003-07-01

    The aim of this study was to investigate the frequency and type of X ray examinations performed on neonates classified according to their birth weight in a neonatal intensive care unit (NICU). In this study, the radiology records of 2408 neonates who were admitted to the NICU of Oita Prefectural Hospital between January 1994 and September 1999 were investigated. This study revealed that the neonates with earlier gestational ages and lower birth weights required longer NICU stays and more frequent X ray examinations made using a mobile X ray unit. The average number of X ray examinations performed on neonates of less than 750 g birth weight was 26 films per neonate. In regard to computed tomography and fluoroscopy, no significant relationship was found between the birth weight and number of X rays. This study revealed that the entrance-surface dose per neonate was dependent upon the birth weight, while the maximum dose was not dependent upon the birth weight. The average neonatal dose in the NICU was predominantly from computed tomography and fluoroscopy. The individual dose varied widely among neonates. (author)

  11. Neonatal doses from X ray examinations by birth weight in a neonatal intensive care unit

    International Nuclear Information System (INIS)

    Ono, K.; Akahane, K.; Aota, T.; Hada, M.; Takano, Y.; Kai, M.; Kusama, T.

    2003-01-01

    The aim of this study was to investigate the frequency and type of X ray examinations performed on neonates classified according to their birth weight in a neonatal intensive care unit (NICU). In this study, the radiology records of 2408 neonates who were admitted to the NICU of Oita Prefectural Hospital between January 1994 and September 1999 were investigated. This study revealed that the neonates with earlier gestational ages and lower birth weights required longer NICU stays and more frequent X ray examinations made using a mobile X ray unit. The average number of X ray examinations performed on neonates of less than 750 g birth weight was 26 films per neonate. In regard to computed tomography and fluoroscopy, no significant relationship was found between the birth weight and number of X rays. This study revealed that the entrance-surface dose per neonate was dependent upon the birth weight, while the maximum dose was not dependent upon the birth weight. The average neonatal dose in the NICU was predominantly from computed tomography and fluoroscopy. The individual dose varied widely among neonates. (author)

  12. Radiation dose to neonates undergoing X-ray imaging in special care baby units in Iran

    International Nuclear Information System (INIS)

    Faghihi, R.; Mehdizadeh, S.; Sina, S.; Alizadeh, F. N.; Zeinali, B.; Kamyab, G. R.; Aghevlian, S.; Khorramdel, H.; Namazi, I.; Heirani, M.; Moshkriz, M.; Mahani, H.; Sharifzadeh, M.

    2012-01-01

    Radiographic imaging has a significant role in the timely diagnosis of the diseases of neonates in intensive care units. The estimation of the dose received by the infants undergoing radiographic examination is of great importance, due to greater more radiosensitivity and longer life expectancy of the neonates and premature babies. In this study, the values of entrance skin dose (ESD), dose area products (DAPs), energy imparted (EI), whole-body dose, effective dose and risk of childhood cancer were estimated using three methods including direct method [using thermoluminescence dosimetry (TLD) chips], indirect method (using tube output) and Monte Carlo (MC) method (using MCNP4C code). In the first step, the ESD of the neonates was directly measured using TLD-100 chips. Fifty neonates, mostly premature, with different weights and gestational ages in five hospitals mostly suffering from respiratory distress syndrome and pneumonia were involved in this study. In the second step, the values of ESD to neonates were indirectly obtained from the tube output in different imaging techniques. The imaging room, incubator, neonates and other components were then simulated in order to obtain the ESD values using the MCNP4C code. Finally, the values of ESD assessed by the three methods were used for calculation of DAP, EI, whole-body dose, effective dose and risk of childhood cancer. The results indicate that the mean ESD per radiograph estimated by the direct, indirect and MC methods are 56.6±4.1, 50.1±3.1 and 54.5±3.3 μGy, respectively. The mean risk of childhood cancer estimated in this study varied between 4.21x10 -7 and 2.72x10 -6 . (authors)

  13. Radiation doses and risks to neonates undergoing radiographic examinations in intensive care units in Tunisia

    Directory of Open Access Journals (Sweden)

    Abir Bouaoun

    2015-12-01

    Full Text Available Purpose: To assess the radiation doses to neonates from diagnostic radiography in order to derive the local diagnostic reference levels (LDRLs for optimisation purposes.Methods: This study was carried out in the neonatal intensive care units (NICU of  two hospitals in Tunis. 134 babies, with weights ranging from 635 g to 6680 g, performed chest-abdomen X-ray examinations. Neonates were categorized into groups of birth weight. For each X-ray examination, patient data and exposure parameters were recorded. Dose area product (DAP was measured and entrance surface dose (ESD was estimated. Effective dose was calculated from the Monte Carlo simulation software PCXMC.Results: DAP values increased with neonatal weight and demonstrated a wide variation (5.0 - 43.0 mGy.cm2, mean 23.4 mGy.cm2 for patient weight from 600 g to 4000 g. A wide variation was also observed for ESD (14 - 93 μGy, mean 55.2 μGy. The LDRLs expressed in term of DAP were estimated to be 17.6 mGy.cm2 and 29.1 mGy.cm2 for the first and the second NICU, respectively. In terms of effective dose, the average value was about 31.6 μSv per single radiological examination. The results show the necessity to use a standardized protocol with high voltage technique combined to lower current time product (mAs values and an adapted collimation which could lead to further reductions in the neonatal doses. Conclusion: This study presents the LDRLs and the effective doses for neonates in two NICUs and demonstrates the necessity to optimize patient protection for this category of patient.

  14. Occupational exposure to radiation in the United Kingdom and its contribution to the genetically effective dose

    Energy Technology Data Exchange (ETDEWEB)

    Binks, W; Marley, W G

    1960-12-01

    It is now the common practice in the United Kingdom for persons who are exposed occupationally to ionizing radiations to be subjected to continuous individual monitoring in order to ensure that the doses that they receive from sources external to the body do not exceed the levels which are regarded as acceptable. In the operation of large-scale monitoring services such as are provided by the Radiological Protection Service (R.P.S.) and by the establishments of the United Kingdom Atomic Energy Authority (U.K.A.E.A.) there is no satisfactory alternative to the use of photographic film, bearing in mind such aspects as simplicity, reliability, accuracy, cheapness, ease of postal transmission of the films in the special holders, and availability of a durable record of the dose received. The Radiological Protection Service provides a film badge service which is widely used by industry. This organization also provides film badges for about one-third of the occupationally exposed persons in National Health Service hospitals; for the remaining hospital workers the majority of establishments undertake their own monitoring arrangements. The United Kingdom Atomic Energy Authority provides its own film badge services for all exposed workers. It is the purpose of this report to summarize the information obtained by the R.P.S. and the U.K.A.E.A. regarding the doses received by occupationally exposed persons. The total genetically effective dose received by the population from occupational exposure is also compared with that received from natural background radiation. This report also summarizes the measurements made by the R.P.S. and the U.K.A.E.A. to check the internal contamination of the body in cases where radioactivity has been ingested or inhaled.

  15. Occupational exposure to radiation in the United Kingdom and its contribution to the genetically effective dose

    International Nuclear Information System (INIS)

    Binks, W.; Marley, W.G.

    1960-01-01

    It is now the common practice in the United Kingdom for persons who are exposed occupationally to ionizing radiations to be subjected to continuous individual monitoring in order to ensure that the doses that they receive from sources external to the body do not exceed the levels which are regarded as acceptable. In the operation of large-scale monitoring services such as are provided by the Radiological Protection Service (R.P.S.) and by the establishments of the United Kingdom Atomic Energy Authority (U.K.A.E.A.) there is no satisfactory alternative to the use of photographic film, bearing in mind such aspects as simplicity, reliability, accuracy, cheapness, ease of postal transmission of the films in the special holders, and availability of a durable record of the dose received. The Radiological Protection Service provides a film badge service which is widely used by industry. This organization also provides film badges for about one-third of the occupationally exposed persons in National Health Service hospitals; for the remaining hospital workers the majority of establishments undertake their own monitoring arrangements. The United Kingdom Atomic Energy Authority provides its own film badge services for all exposed workers. It is the purpose of this report to summarize the information obtained by the R.P.S. and the U.K.A.E.A. regarding the doses received by occupationally exposed persons. The total genetically effective dose received by the population from occupational exposure is also compared with that received from natural background radiation. This report also summarizes the measurements made by the R.P.S. and the U.K.A.E.A. to check the internal contamination of the body in cases where radioactivity has been ingested or inhaled

  16. Enhanced Engraftment of a Very Low-Dose Cord Blood Unit in an Adult Haemopoietic Transplant by Addition of Six Mismatched Viable Cord Units

    Directory of Open Access Journals (Sweden)

    Stephen J. Proctor

    2010-01-01

    , supported by six mismatched cord blood units (one unit per 10 kg recipient weight. No adverse reaction occurred following the infusion of mismatched units and engraftment of the suboptimal-dose matched unit occurred rapidly, with no molecular evidence of engraftment of mismatched cords. Early molecular remission of ALL was demonstrated using a novel PCR for a mitochondrial DNA mutation in the leukaemic clone. The cell dose of the matched cord was well below that recommended to engraft a 70 kg recipient. We suggest that a factor or factors in the mismatched cords enhanced/supported engraftment of the matched cord.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  18. Report of the Nuclear Energy Agency expert group on gut transfer factors: implications for dose per unit intake

    International Nuclear Information System (INIS)

    1988-01-01

    This note describes the gut transfer factors recommended by an Expert Group of the Nuclear Energy Agency for intakes of certain important elements in food and drinking water. The evidence behind the recommendations is discussed and their implications for dose per unit intake is investigated. It is found that in many cases the dose per unit intake calculated using the gut uptake factor recommended by the Expert Group is similar to that calculated using the recommendations of ICRP Publication 30. However, in some cases there are substantial increases in dose per unit intake. The largest increases are by a factor of fifty for intakes of certain thorium isotopes by infants. (author)

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

    Science.gov (United States)

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

    2012-12-01

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

  20. Dose mapping in working space of KORI unit 1 using MCNPX code

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C. W.; Shin, C. H.; Kim, J. G. [Hanyang University, Seoul (Korea, Republic of); Kim, S. Y. [Innovative Techonology Center for Radiation Safety, Seoul (Korea, Republic of)

    2004-07-01

    Radiation field analysis in nuclear power plant mainly depends on actual measurements. In this study, the analysis using computational calculation is performed to overcome the limits of measurement and provide the initial information for unfolding. The radiation field mapping is performed, which makes it possible to analyze the trends of the radiation filed for whole space. By using MCNPX code, containment building inside is modeled for KORI unit 1 cycle 21 under operation. Applying the neutron spectrum from the operating reactor as a radiation source, the ambient doses are calculated in the whole space, containment building inside, for neutron and photon fields. Dose mapping is performed for three spaces, 6{approx}20, 20{approx}44, 44{approx}70 ft from bottom of the containment building. The radiation distribution in dose maps shows the effects from structures and materials of components. With this dose maps, radiation field analysis contained the region near the detect position. The analysis and prediction are possible for radiation field from other radiation source or operating cycle.

  1. A program on quality assurance and dose calibration for radiation therapy units in Venezuela

    International Nuclear Information System (INIS)

    Padilla, M.C. de; Carrizales, L.; Diaz, J.; Gutt, F.; Cozman, A.

    1996-01-01

    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. A program on quality assurance and dose calibration for radiation therapy units in Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, M.C. de; Carrizales, L; Diaz, J; Gutt, F; Cozman, A [Instituto Venezolano de Investigaciones Cientificas, Caracas (Venezuela). Lab. de Calibracion Dosimetrica

    1996-08-01

    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.

  3. Analysis of female radiation workers dose records in the DAE Units of Andhra Pradesh

    International Nuclear Information System (INIS)

    Padma Savitri, P.; Kamble, M.K.; Reddy, K.S.

    2010-01-01

    Basis for control of occupational exposures of women is same as that of men except for pregnant women. Percentage of women working in radiation areas of DAE has marginally increased in the last three decades. This paper analysed the data on the externally received personal dose equivalent for female radiation workers who have been exposed ti ionizing radiation in different occupations of DAE units in Andhra Pradesh. From this study we can say confidently that it is equally safe for women to work in radiation areas as long as they follow radiation protection principles. Hence, women in India should be made aware that it is safe to work in radiation areas and DAE is taking their care by periodical medical checkups, maintaining dose records, etc

  4. Measurement of irradiation doses secondary to bedside radiographs in a medical intensive care unit

    Energy Technology Data Exchange (ETDEWEB)

    Boles, J M; Boussert, F; Manens, J P; Le Cam, B; Bellet, M; Garre, M

    1987-01-01

    The authors prospectively studied the radiation doses to radio-sensitive organs secondary to bedside radiographs in intensive care patients and in a control phantom. Dosimeters were taped on different organs during each bedside X-ray. The mean radiation doses, expressed in 10(-5) Gy (m-rad), for an ''average patient'' who was hospitalized 9 days and had 6 chest X-rays were respectively: 292 to the sternal bone marrow; 239 to the thyroid gland; 3 to the testes; 1 to the ovaries; 605 to the eye for 2 maxillary sinus X-rays. No diffused irradiation was measured during a 2-month period in the intensive care unit nor on dosimeters worn by four nurses.

  5. Survey of radiation doses received by atomic-bomb survivors residing in the United States

    International Nuclear Information System (INIS)

    Kerr, G.D.; Yamada, H.; Marks, S.

    1976-01-01

    A survey has been completed of 300 of an estimated 500 to 750 survivors of the atomic bombings in Hiroshima and Nagasaki who reside in the United States. Distributions with respect to age, sex, citizenship status, distance from the hypocenter at the time of bombing, and dose from immediate weapon radiation have been tabulated from the results and are presented for this group of 300 survivors. Also presented are survey results concerning exposures to residual radiation from fallout and neutron-induced radioactivity in the areas adjacent to the hypocenter

  6. Evaluation of mean glandular dose in a full-field digital mammography unit in Tabriz (IR)

    International Nuclear Information System (INIS)

    Riabi, H. A.; Mehnati, P.; Mesbahi, A.

    2010-01-01

    This study was aimed at evaluating the mean glandular dose (MGD) and affecting factors during mammography examinations by a full-field digital mammography unit. An extensive quality control program was performed to assure that the unit is properly working. Required information including compressed breast thickness (CBT), breast parenchymal pattern and technical factors used for imaging were recorded. An entrance skin exposure measurement was also performed using slabs of polymethylmethacrylate with 2-8 cm thickness. On the basis of recorded information and measured data, the MGD was estimated for 1145 mammography examinations obtained from 298 patients. Mean CBTs of 4.9 and 5.8 cm and MGDs of 2 and 2.4 mGy were observed for cranio-caudal and medio-lateral oblique views, respectively. Significant correlation was seen between MGD and CBT, breast parenchymal pattern and applied kVp and mAs. (authors)

  7. Chronic dietary exposure to a low-dose mixture of genistein and vinclozolin modifies the reproductive axis, testis transcriptome, and fertility.

    Science.gov (United States)

    Eustache, Florence; Mondon, Françoise; Canivenc-Lavier, Marie Chantal; Lesaffre, Corinne; Fulla, Yvonne; Berges, Raymond; Cravedi, Jean Pierre; Vaiman, Daniel; Auger, Jacques

    2009-08-01

    The reproductive consequences and mechanisms of action of chronic exposure to low-dose endocrine disruptors are poorly understood. We assessed the effects of a continuous, low-dose exposure to a phytoestrogen (genistein) and/or an antiandrogenic food contaminant (vinclozolin) on the male reproductive tract and fertility. Male rats were exposed by gavage to genistein and vinclozolin from conception to adulthood, alone or in combination, at low doses (1 mg/kg/day) or higher doses (10 and 30 mg/kg/day). We studied a number of standard reproductive toxicology end points and also assessed testicular mRNA expression profiles using long-oligonucleotide microarrays. The low-dose mixture and high-dose vinclozolin produced the most significant alterations in adults: decreased sperm counts, reduced sperm motion parameters, decreased litter sizes, and increased post implantation loss. Testicular mRNA expression profiles for these exposure conditions were strongly correlated. Functional clustering indicated that many of the genes induced belong to the "neuroactive ligand-receptor interactions" family encompassing several hormonally related actors (e.g., follicle-stimulating hormone and its receptor). All exposure conditions decreased the levels of mRNAs involved in ribosome function, indicating probable decreased protein production. Our study shows that chronic exposure to a mixture of a dose of a phytoestrogen equivalent to that in the human diet and a low dose-albeit not environmental-of a common anti-androgenic food contaminant may seriously affect the male reproductive tract and fertility.

  8. Radiation dose in the neonatal intensive care unit of Antoine Beclere Hospital

    International Nuclear Information System (INIS)

    Lebreton, C.; Rehel, J. L.; Aubert, B.; Musset, D.

    2006-01-01

    As part of a program aiming a better knowledge of the medical exposure of the french population and in the frame of the principle of optimisation, a study of radiation doses to neonates was carried out in neonatal intensive care unit of Antoine Beclere hospital. From March to August 2005, entrance surface dose (ESD) received by 63 neonates classified according the their weight (184 X-ray examinations) was measured with thermoluminescent dosimeters (TLD) during examination. The mean ESD ESD per exposure was found between 20 and 37 μGy according to the weight of neonates. The newborn of less than 1000 g at birth have a mean of 20 X-ray examinations. Above 1000 g the number of X-ray examinations was between 5 and 8.5. During their stay in neonatal intensive care unit, the total ESD of neonates was from 500 μGy for the smallest Neonates (<1000 g) and the other respectively. Results indicate that neonate exposition, is very small compared with french and international data. ESD was significantly lower than the french reference level of 80 μGy. (Author)

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

    International Nuclear Information System (INIS)

    Rodgers, Reginald C.

    1978-01-01

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

  10. Evaluation of the population dose due to the gaseous emission of a radioisotopes production unit

    International Nuclear Information System (INIS)

    Gordon, A.M.P.L.; Jacomino, V.M.F.; Sordi, G.-M.A.A.

    1990-05-01

    In order to control the emission of gaseous radioactive iodine from the unit responsible for the production of radioisotopes of IPEN-CNEN/SP, a discharge monitoring is carried out. In 1988 an activity of 65 GBq of I-131 was discharged to the environment. Based upon this value and the site analysis, the effective equivalent dose in the general public was evaluated for normal operation and for an incidental discharge. The evaluation was carried out by using a diffusion atmospheric model, 500 to 7000 m away from the discharge point and using 8 different wind direction sectors. The critical group was identified as being the people who lives 3000 m far from the discharge point, in the diffusion sector NW. The dose evaluated at this point is 10 9 times lower than the annual dose limit for individual of the public, according to Radiological Protection Standards. The derived limit for discharge of iodine was also evaluated and it was concluded that the IPEN-CNEN/SP can increase their production up to a level which results in an annual discharge of 1,5 x 10 12 of I-131. (author) [pt

  11. 'Dose per unit content' functions: A robust tool for the interpretation of bioassay data

    International Nuclear Information System (INIS)

    Berkovski, V.; Bonchuk, Y.; Ratia, G.

    2003-01-01

    The purposes of this study were to investigate the influence of the consequences of the lack of primary bioassay information and to elaborate approaches which could improve the reliability of dose assessments. The aggregated time-dependent functions 'dose per unit organ (excretion) content' z(t) have been proposed in this study as a convenient and reliable tool for bioassay. The analysis of the variation of z with changes of AMAD has demonstrated the existence of areas of the relative invariance of z, which permits the selection of one (reference) function z for the whole area of stability. Within the framework of such an approach an arbitrary set of bioassay data can be approximated by the linear combination F(t) S i E/ i z(t-t i ), whereI> F(t) function of time t, which approximates the observed bioassay time trend; t i = time shift of the acute intake i; E i effective dose, associated with the acute intake i (the two last parameters are results of the approximation procedure). (author)

  12. Measuring instruments of the Physikalisch-Technische Bundesanstalt for realization of the units of the dosimetric quantities standard ion dose, photon-equivalent dose and air-kerma

    International Nuclear Information System (INIS)

    Engelke, B.A.; Oetzmann, W.; Struppek, G.

    1988-08-01

    The realization of the units of the dosimetric quantities exposure, air-kerma and photon-equivalent dose is an important task of the Physikalisch-Technische Bundesanstalt. The report describes the measuring instruments and other technical equipment as well as the determination of the numerous corrections needed. All data and correction factors required for the realization of the units mentioned above are given in many diagrams and tables. (orig.) [de

  13. Atrazine Does Not Induce Pica Behavior at Doses that Increase Hypothalamic-Pituitary-Adrenal Axis Activation and Cause Conditioned Taste Avoidance.

    Science.gov (United States)

    Previous work has shown that a single oral administration of atrazine (ATR), a chlorotriazine herbicide, induces dose-dependent increases in plasma adrenocorticotropic hormone (ACTH), serum corticosterone (CORT) and progesterone. The mechanism for these effects is unknown. To tes...

  14. SU-E-J-96: Multi-Axis Dose Accumulation of Noninvasive Image-Guided Breast Brachytherapy Through Biomechanical Modeling of Tissue Deformation Using the Finite Element Method

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, MJ [Tufts University School of Medicine, Boston, MA (United States); Ghadyani, HR [SUNY Farmingdale State College, Farmingdale, NY (United States); Bastien, AD; Lutz, NN [Univeristy Massachusetts Lowell, Lowell, MA (United States); Hepel, JT [Rhode Island Hospital, Providence, RI (United States)

    2015-06-15

    Purpose: Noninvasive image-guided breast brachytherapy delivers conformal HDR Ir-192 brachytherapy treatments with the breast compressed, and treated in the cranial-caudal and medial-lateral directions. This technique subjects breast tissue to extreme deformations not observed for other disease sites. Given that, commercially-available software for deformable image registration cannot accurately co-register image sets obtained in these two states, a finite element analysis based on a biomechanical model was developed to deform dose distributions for each compression circumstance for dose summation. Methods: The model assumed the breast was under planar stress with values of 30 kPa for Young’s modulus and 0.3 for Poisson’s ratio. Dose distributions from round and skin-dose optimized applicators in cranial-caudal and medial-lateral compressions were deformed using 0.1 cm planar resolution. Dose distributions, skin doses, and dose-volume histograms were generated. Results were examined as a function of breast thickness, applicator size, target size, and offset distance from the center. Results: Over the range of examined thicknesses, target size increased several millimeters as compression thickness decreased. This trend increased with increasing offset distances. Applicator size minimally affected target coverage, until applicator size was less than the compressed target size. In all cases, with an applicator larger or equal to the compressed target size, > 90% of the target covered by > 90% of the prescription dose. In all cases, dose coverage became less uniform as offset distance increased and average dose increased. This effect was more pronounced for smaller target-applicator combinations. Conclusions: The model exhibited skin dose trends that matched MC-generated benchmarking results and clinical measurements within 2% over a similar range of breast thicknesses and target sizes. The model provided quantitative insight on dosimetric treatment variables over

  15. SU-E-J-96: Multi-Axis Dose Accumulation of Noninvasive Image-Guided Breast Brachytherapy Through Biomechanical Modeling of Tissue Deformation Using the Finite Element Method

    International Nuclear Information System (INIS)

    Rivard, MJ; Ghadyani, HR; Bastien, AD; Lutz, NN; Hepel, JT

    2015-01-01

    Purpose: Noninvasive image-guided breast brachytherapy delivers conformal HDR Ir-192 brachytherapy treatments with the breast compressed, and treated in the cranial-caudal and medial-lateral directions. This technique subjects breast tissue to extreme deformations not observed for other disease sites. Given that, commercially-available software for deformable image registration cannot accurately co-register image sets obtained in these two states, a finite element analysis based on a biomechanical model was developed to deform dose distributions for each compression circumstance for dose summation. Methods: The model assumed the breast was under planar stress with values of 30 kPa for Young’s modulus and 0.3 for Poisson’s ratio. Dose distributions from round and skin-dose optimized applicators in cranial-caudal and medial-lateral compressions were deformed using 0.1 cm planar resolution. Dose distributions, skin doses, and dose-volume histograms were generated. Results were examined as a function of breast thickness, applicator size, target size, and offset distance from the center. Results: Over the range of examined thicknesses, target size increased several millimeters as compression thickness decreased. This trend increased with increasing offset distances. Applicator size minimally affected target coverage, until applicator size was less than the compressed target size. In all cases, with an applicator larger or equal to the compressed target size, > 90% of the target covered by > 90% of the prescription dose. In all cases, dose coverage became less uniform as offset distance increased and average dose increased. This effect was more pronounced for smaller target-applicator combinations. Conclusions: The model exhibited skin dose trends that matched MC-generated benchmarking results and clinical measurements within 2% over a similar range of breast thicknesses and target sizes. The model provided quantitative insight on dosimetric treatment variables over

  16. Emotional exhaustion and overcommitment to work are differentially associated with hypothalamus-pituitary-adrenal (HPA) axis responses to a low-dose ACTH1-24 (Synacthen) and dexamethasone-CRH test in healthy school teachers.

    Science.gov (United States)

    Wolfram, Maren; Bellingrath, Silja; Feuerhahn, Nicolas; Kudielka, Brigitte M

    2013-01-01

    Evidence for a detrimental impact of chronic work stress on health has accumulated in epidemiological research. Recent studies indicate altered hypothalamus-pituitary-adrenal (HPA) axis regulation as a possible biological pathway underlying the link between stress and disease. However, the direction of dysregulation remains unclear, with reported HPA hyper- or hyporeactivity. To disentangle potential effects on different functional levels in the HPA axis, we examined responses using two pharmacological stimulation tests in 53 healthy teachers (31 females, 22 males; mean age: 49.3 years; age range: 30-64 years): a low-dose adrenocorticotrophic hormone (ACTH(1-24), Synacthen) test was used to assess adrenal cortex sensitivity and the combined dexamethasone-corticotropin releasing hormone (DEX-CRH) test to examine pituitary and adrenal cortex reactivity. Blood and saliva samples were collected at - 1,+15,+30,+45,+60,+90,+120 min. Emotional exhaustion (EE), the core dimension of burnout, was measured with the Maslach Burnout Inventory. Overcommitment (OC) was assessed according to Siegrist's effort-reward-imbalance model. We found a significant association between EE and higher plasma cortisol profiles after Synacthen (p = 0.045). By contrast, OC was significantly associated with attenuated ACTH (p = 0.045), plasma cortisol (p = 0.005), and salivary cortisol (p = 0.023) concentrations following DEX-CRH. Results support the notion of altered HPA axis regulation in chronically work-stressed teachers, with differential patterns of hyper- and hyporeactivity depending on individual stress condition and the tested functional level of the HPA axis.

  17. Doses for various pathways to man based on unit concentrations of radionuclides pertinent to decontamination and decommissioning of properties

    International Nuclear Information System (INIS)

    Hill, G.S.

    1979-03-01

    This report gives dose tabulations for unit concentrations of radionuclides likely to be encountered in the decommissioning of real estate contaminated with uranium and thorium ores and residues. The reported doses may be ratioed to known air, soil, and water concentrations, exposure times, and intakes to estimate the total radiation dose for individuals exposed to the facilities. These dose estimates may be used in developing criteria to determine appropriate remedial actions for returning the properties to useful purposes and for establishing restrictions for such use

  18. Behaviors of the percentage depth dose curves along the beam axis of a phantom filled with different clinical PTO objects, a Monte Carlo Geant4 study

    International Nuclear Information System (INIS)

    EL Bakkali, Jaafar; EL Bardouni, Tarek; Safavi, Seyedmostafa; Mohammed, Maged; Saeed, Mroan

    2016-01-01

    The aim of this work is to assess the capabilities of Monte Carlo Geant4 code to reproduce the real percentage depth dose (PDD) curves generated in phantoms which mimic three important clinical treatment situations that include lung slab, bone slab, bone-lung slab geometries. It is hoped that this work will lead us to a better understanding of dose distributions in an inhomogeneous medium, and to identify any limitations of dose calculation algorithm implemented in the Geant4 code. For this purpose, the PDD dosimetric functions associated to the three clinical situations described above, were compared to one produced in a homogeneous water phantom. Our results show, firstly, that the Geant4 simulation shows potential mistakes on the shape of the calculated PDD curve of the first physical test object (PTO), and it is obviously not able to successfully predict dose values in regions near to the boundaries between two different materials. This is, surely due to the electron transport algorithm and it is well-known as the artifacts at interface phenomenon. To deal with this issue, we have added and optimized the StepMax parameter to the dose calculation program; consequently the artifacts due to the electron transport were quasi disappeared. However, the Geant4 simulation becomes painfully slow when we attempt to completely resolve the electron artifact problems by considering a smaller value of an electron StepMax parameter. After electron transport optimization, our results demonstrate the medium-level capabilities of the Geant4 code to modeling dose distribution in clinical PTO objects. - Highlights: • Assessment of the capabilities of Geant4 code to reproduce the PDD curves in heterogeneities. • Resolving artifacts due to the electron transport. • Understanding in dose distribution differences in interfaces which include water, bone, and lung interfaces.

  19. [Phenylephrine dosing error in Intensive Care Unit. Case of the trimester].

    Science.gov (United States)

    2013-01-01

    A real clinical case reported to SENSAR is presented. A patient admitted to the surgical intensive care unit following a lung resection, suffered arterial hypotension. The nurse was asked to give the patient 1 mL of phenylephrine. A few seconds afterwards, the patient experienced a hypertensive crisis, which resolved spontaneously without damage. Thereafter, the nurse was interviewed and a dosing error was identified: she had mistakenly given the patient 1 mg of phenylephrine (1 mL) instead of 100 mcg (1 mL of the standard dilution, 1mg in 10 mL). The incident analysis revealed latent factors (event triggers) due to the lack of protocols and standard operating procedures, communication errors among team members (physician-nurse), suboptimal training, and underdeveloped safety culture. In order to preempt similar incidents in the future, the following actions were implemented in the surgical intensive care unit: a protocol for bolus and short lived infusions (del Dolor. Published by Elsevier España. All rights reserved.

  20. Intra-individual diagnostic image quality and organ-specific-radiation dose comparison between spiral cCT with iterative image reconstruction and z-axis automated tube current modulation and sequential cCT

    International Nuclear Information System (INIS)

    Wenz, Holger; Maros, Máté E.; Meyer, Mathias; Gawlitza, Joshua; Förster, Alex; Haubenreisser, Holger; Kurth, Stefan; Schoenberg, Stefan O.; Groden, Christoph; Henzler, Thomas

    2016-01-01

    •Superiority of spiral versus sequential cCT in image quality and organ-specific-radiation dose.•Spiral cCT: lower organ-specific-radiation-dose in eye lense compared to tilted sequential cCT.•State-of-the-art IR spiral cCT techniques has significant advantages over sequential cCT techniques. Superiority of spiral versus sequential cCT in image quality and organ-specific-radiation dose. Spiral cCT: lower organ-specific-radiation-dose in eye lense compared to tilted sequential cCT. State-of-the-art IR spiral cCT techniques has significant advantages over sequential cCT techniques. To prospectively evaluate image quality and organ-specific-radiation dose of spiral cranial CT (cCT) combined with automated tube current modulation (ATCM) and iterative image reconstruction (IR) in comparison to sequential tilted cCT reconstructed with filtered back projection (FBP) without ATCM. 31 patients with a previous performed tilted non-contrast enhanced sequential cCT aquisition on a 4-slice CT system with only FBP reconstruction and no ATCM were prospectively enrolled in this study for a clinical indicated cCT scan. All spiral cCT examinations were performed on a 3rd generation dual-source CT system using ATCM in z-axis direction. Images were reconstructed using both, FBP and IR (level 1–5). A Monte-Carlo-simulation-based analysis was used to compare organ-specific-radiation dose. Subjective image quality for various anatomic structures was evaluated using a 4-point Likert-scale and objective image quality was evaluated by comparing signal-to-noise ratios (SNR). Spiral cCT led to a significantly lower (p < 0.05) organ-specific-radiation dose in all targets including eye lense. Subjective image quality of spiral cCT datasets with an IR reconstruction level 5 was rated significantly higher compared to the sequential cCT acquisitions (p < 0.0001). Consecutive mean SNR was significantly higher in all spiral datasets (FBP, IR 1–5) when compared to sequential cCT with a mean

  1. Impact of digitalization of mammographic units on average glandular doses in the Flemish Breast Cancer Screening Program

    OpenAIRE

    De Hauwere, An; Thierens, Hubert

    2012-01-01

    The impact of digitalization on the average glandular doses in 49 mammographic units participating in the Flemish Breast Cancer Screening Program was studied. Screen-film was changed to direct digital radiography and computed radiography in 25 and 24 departments respectively. Average glandular doses were calculated before and after digitalization for different PMMA-phantom thicknesses and for groups of 50 successive patients. For the transition from screen-film to computed radiography both ph...

  2. Measurements of X ray absorbed doses to dental patients in two dental X ray units in Nigeria

    International Nuclear Information System (INIS)

    Ogundare, F.O.; Oni, O.M.; Balogun, F.A.

    2002-01-01

    Measurements of absorbed doses from radiographic examinations to various anatomical sites in the head and neck of patients with an average age of 45 years using intra-oral dental radiography have been carried out. LiF (TLD-100) dosemeters were used for the measurements of the absorbed dose. The measured absorbed doses to the various anatomical sites in the two units are reported, discussed and compared with results from the literature. Quality control measurements were also performed using a Victoreen quality control test device on the X ray units. The tube voltage accuracies for the two units were found to be within acceptable limits (less than ±10%). On the other hand the exposure time accuracies for these units have large deviations (>20%). These results and those that have been reported in the literature may be an indication that high patient doses are common in most dental X ray centres and countries. As a result of this, regular compliance and performance checks of dental diagnostic X ray equipment are essential in order to ensure proper performance and to minimise unnecessary patient and operator doses. (author)

  3. Heel Effect: Dose Mapping And Profiling For Mobile C-Arm Fluoroscopy Unit Toshiba SXT-1000A

    International Nuclear Information System (INIS)

    Husaini Salleh; Mohd Khalid Matori; Muhammad Jamal Md Isa; Mohd Ramli Arshad; Shahrul Azlan Azizan; Mohd Firdaus Abdul Rahman; Md Khairusalih Md Zin

    2014-01-01

    Heel Effect is the well known phenomena in x-ray production. It contributes the effect to image formation and as well as scattered radiation. But there is paucity in the study related to heel effect. This study is for mapping and profiling the dose on the surface of water phantom by using mobile C-arm unit Toshiba SXT-1000A. Based on the result the dose profile is increasing up to about 57 % from anode to cathode bound of the irradiated area. This result and information can be used as a guide to manipulate these phenomena for better image quality and radiation safety for this specific and dedicated fluoroscopy unit. (author)

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

    International Nuclear Information System (INIS)

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

    1980-01-01

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

  5. Upgrading of Alum Preparation and Dosing Unit for Sharq Dijla Water Treatment Plant by Using Programmable Logic Controller System

    Directory of Open Access Journals (Sweden)

    Aumar Al-Nakeeb

    2018-02-01

    Full Text Available One of the important units in Sharq Dijla Water Treatment Plant (WTP first and second extensions are the alum solution preparation and dosing unit. The existing operation of this unit accomplished manually starting from unloading the powder alum in the preparation basin and ending by controlling the alum dosage addition through the dosing pumps to the flash mix chambers. Because of the modern trend of monitoring and control the automatic operation of WTPs due to the great benefits that could be gain from optimum equipment operation, reducing the operating costs and human errors. This study deals with how to transform the conventional operation to an automatic monitoring and controlling system depending on a Programmable Logic Controller (PLC and online sensors for alum preparation and dosing unit in Sharq Dijla WTP. PLC system will receive, analyze transmitting data, compare them with preset points then automatically orders the operational equipment (such as pumps, valves, and mixers in a way that guarantees the safe and appropriate operation of the unit. As a result of Process and Instrumentation Diagrams (PID that were prepared in this study, these units can be fully operating and manage by using Supervisory Control and Data Acquisition (SCADA system.

  6. A Cesium Rare-Earth Silicate Cs3 RESi6 O15 (RE=Dy-Lu, Y, In): The Parent of an Unusual Structural Class Featuring a Remarkable 57 Å Unit Cell Axis.

    Science.gov (United States)

    Terry, Rylan; Vinton, Daniel; McMillen, Colin D; Kolis, Joseph W

    2018-02-19

    The structure of Cs 3 RESi 6 O 15 , where RE=Dy-Lu, Y, In, is unusual in that it contains octahedrally coordinated rare-earth ions; their relative orientation dictates the structure, as they rotate about the c-axis supported by the cyclic Si 6 O 15 framework. The repeat unit of the rotation is eight units generating a very long (ca. 57 Å) unit cell axis. This unusual repeat unit is created by the structural flexibility of the hexasilicate ring, which is in turn affected by the size of the rare earth ion as well as the size of alkali ion residing within the silicate layers. Previous work showed for the smaller Sc 3+ ion, the rotation of the octahedra is not sufficient to achieve closure at an integral repeat unit and an incommensurate structure results. The products are prepared as large, high quality single crystals using a high-temperature (650 °C) hydrothermal method with CsOH and F - mineralizers. The presence of fluoride is essential to the formation of the product. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. A cesium rare-earth silicate Cs{sub 3}RESi{sub 6}O{sub 15} (RE = Dy-Lu, Y, In). The parent of an unusual structural class featuring a remarkable 57 Aa unit cell axis

    Energy Technology Data Exchange (ETDEWEB)

    Terry, Rylan; Vinton, Daniel; McMillen, Colin D.; Kolis, Joseph W. [Department of Chemistry and Center for Optical Materials Science and Engineering Technologies (COMSET), Clemson University, H.L. Hunter Laboratories (United States)

    2018-02-19

    The structure of Cs{sub 3}RESi{sub 6}O{sub 15}, where RE = Dy-Lu, Y, In, is unusual in that it contains octahedrally coordinated rare-earth ions; their relative orientation dictates the structure, as they rotate about the c-axis supported by the cyclic Si{sub 6}O{sub 15} framework. The repeat unit of the rotation is eight units generating a very long (ca. 57 Aa) unit cell axis. This unusual repeat unit is created by the structural flexibility of the hexasilicate ring, which is in turn affected by the size of the rare earth ion as well as the size of alkali ion residing within the silicate layers. Previous work showed for the smaller Sc{sup 3+} ion, the rotation of the octahedra is not sufficient to achieve closure at an integral repeat unit and an incommensurate structure results. The products are prepared as large, high quality single crystals using a high-temperature (650 C) hydrothermal method with CsOH and F{sup -} mineralizers. The presence of fluoride is essential to the formation of the product. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

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

    International Nuclear Information System (INIS)

    Hipkin, J.

    1977-01-01

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

  9. Evaluation of radiation dose to neonate on special care baby unit

    International Nuclear Information System (INIS)

    Adam, A. Y. I.

    2012-08-01

    A total of 132 patients in One-armed Maternity Hospital in Khartoum State. ESDs from patient exposure parameters using DosCal software. Effective doses (E) were calculated using published conversion factor and methods recommended by the national Radiological Protection Board (NRPB). The mean patient dose was 80 μGy per procedures. The mean organ doses per procedures were ranged between 0.04 to 0.0002 mGy per procedure. The mean effective dose was 0.02 mSv. Patients' doses showed wide variations. This variation in patient dose could be attributed to the variation in patient weight, tube voltage and tube current time product.The radiation risk per procedures was very low. However, due to their sensitive tissues, additional dose reduction is justifiable. A dedicated x-ray machine with additional filtration is recommended for patient dose reductions. (Author)

  10. ALARA review of the maintenance and repair jobs of repetitive high radiation dose at Kori Unit 3 and 4

    International Nuclear Information System (INIS)

    Cho, Y.H.; Moon, J.H.; Kang, C.S.; Lee, J.S.; Lee, D.H.

    2003-01-01

    The policy of maintaining occupational radiation dose (ORD) as low as reasonably achievable (ALARA) requires the effective reduction of ORD in the phases of design as well as operation of nuclear power plants. It has been identified that a predominant portion of ORD arises during maintenance and repair operations at nuclear power plants. The cost-effective reduction of ORD cannot be achieved without a comprehensive analysis of accumulated ORD data of existing nuclear power plants. To identify the jobs of repetitive high ORD, the ORD data of Kori Units 3 and 4 over 10-year period from 1986 to 1995 were compiled into the PC-based ORD database program. As the radiation job classification structure, 26 main jobs are considered, most of which are further subdivided into detailed jobs. According to the order of the collective dose values for 26 main jobs, 10 jobs of high collective dose are identified. As an ALARA review, then, top 10 jobs of high collective dose are statistically analyzed with regard to 1) dose rate, 2) crew number and 3) job frequency that are the factors determining the collective dose for the radiation job of interest. Through the ALARA review, main reasons causing to high collective dose values are identified as follows. The high collective dose of RCP maintenance job is mainly due to the large crew number and the high job frequency. The characteristics of refueling job are similar to those of RCP maintenance job. However, the high collective doses of SG-related jobs such as S/G nozzle dam job, S/G man-way job and S/G tube maintenance job are mainly due to high radiation dose rate. (author)

  11. Terms and definitions in the field of radiological technique. Dose quantities and units. Begriffe und Benennungen in der radiologischen Technik. Dosisgroessen und Dosiseinheiten

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    The standard gives the terms and definitions of concepts, dose quantities and units. The radiation field condition 'secondary electron equilibrium', which forms part of the definition of standard ion dose, is given more precisely. The term 'free in air' is used in its original meaning, i.e. characterization of measuring conditions excluding avoidable stray radiation, which deviates from DIN 6814, part 3/06.72. Dosemeters for measurement of standard ion dose of air kerma are calibrated 'free in air', but this calibration condition is not part of the quantity definition. The quantities standard ion dose or air kerma therefore can also be measured in any other material. The qunatitative relationships between standard ion dose and the quantities 'exposure' and air kerma, as given in the ICRU publication 33 'Quantities and Units' (1980), are explained. The standard introduces the SI units Gray (for energy dose), Sievert (for dose equivalent), and Becquerel (for the activity of a radioactive substance). As the change to the SI units conceals the approximated equality of the numerical values of the standrd ion dose of photon radiation in roentgen, of the energy dose for soft tissue in rad, and of the dose equivalent in rem, new definitions are given in accordance with ICRU 33 for the quantities specified dose rate, dose rate constant, and area exposure product. These definitions use the terms 'energy dose' and 'kerma'. The dose concepts applied in the field of radiation protection, especially ambient dose and individual dose, are defined as dose equivalents in compliance with the Radiation Protection Ordinance. The relevant sections present information on the conversion of standard ion dose values to the corresponding values of kerma, energy dose, or dose equivalent.

  12. Radioactive waste evacuation of the sources of a low dose rate brachytherapy unit

    International Nuclear Information System (INIS)

    Serrada, A.; Huerga, C.; Santa Olalla, I.; Vicedo, A.; Corredoira, E.; Plaza, R.; Vidal, J.; Tellez, M.

    2006-01-01

    Introduction The second class Radioactive Installation start -up authorization makes responsible for its security to the installation exploiter and supervisor. The specifications established in the authorization, which are mandatory, point out several actions, some of these actions are the hermeticity tests of radioactive sources an radiologic controls of environment dosimetry. It is necessary to optimize the time spent in each activity, managing them as reasonably as possible. An important matter to take into account is to keep and control only those radioactive or radiological equipment which, even if are in work, have an appropriate performance for the patient treatment Material And Method a Paz hospital has an intracavity brachytherapy (L.D.R.), Curietron model. The Radioprotection Department proposed to remove from service the unit due to its age, this was carried out by the Commission of Guarantee and Quality Control. There were different solutions taken into account to decommission the unit, finally the option chosen as the most convenient for the installation was to manage directly the withdrawal of the radioactive material which consisted of seven Cs-137 probes model CsM1 and total nominal certificated activity of 7770 MBq ( 210 mCi ) dated in May 2005. It also has to be considered as a radioactive waste the inner storage elements of the Curietron and the transport and storage curie stock, built with depleted uranium. To accomplish this aim an evacuation container was designed consisting of an alloy of low-melting point (M.C.P.96), which fulfills the transport conditions imposed by E.N.R.E.S.A. ( Empresa Nacional de Residuos Radiactivos, S.A). A theoretical calculation was performed to estimate the thickness of the shield which adequate to the rate of dose in contact demanded. Accuracy of these calculations has been verified using T.L. dosimetry. Results The radiation levels during the extraction intervention of the radioactive probes and its transfer to

  13. Ultralow dose dentomaxillofacial CT imaging and iterative reconstruction techniques: variability of Hounsfield units and contrast-to-noise ratio

    Science.gov (United States)

    Bischel, Alexander; Stratis, Andreas; Kakar, Apoorv; Bosmans, Hilde; Jacobs, Reinhilde; Gassner, Eva-Maria; Puelacher, Wolfgang; Pauwels, Ruben

    2016-01-01

    Objective: The aim of this study was to evaluate whether application of ultralow dose protocols and iterative reconstruction technology (IRT) influence quantitative Hounsfield units (HUs) and contrast-to-noise ratio (CNR) in dentomaxillofacial CT imaging. Methods: A phantom with inserts of five types of materials was scanned using protocols for (a) a clinical reference for navigated surgery (CT dose index volume 36.58 mGy), (b) low-dose sinus imaging (18.28 mGy) and (c) four ultralow dose imaging (4.14, 2.63, 0.99 and 0.53 mGy). All images were reconstructed using: (i) filtered back projection (FBP); (ii) IRT: adaptive statistical iterative reconstruction-50 (ASIR-50), ASIR-100 and model-based iterative reconstruction (MBIR); and (iii) standard (std) and bone kernel. Mean HU, CNR and average HU error after recalibration were determined. Each combination of protocols was compared using Friedman analysis of variance, followed by Dunn's multiple comparison test. Results: Pearson's sample correlation coefficients were all >0.99. Ultralow dose protocols using FBP showed errors of up to 273 HU. Std kernels had less HU variability than bone kernels. MBIR reduced the error value for the lowest dose protocol to 138 HU and retained the highest relative CNR. ASIR could not demonstrate significant advantages over FBP. Conclusions: Considering a potential dose reduction as low as 1.5% of a std protocol, ultralow dose protocols and IRT should be further tested for clinical dentomaxillofacial CT imaging. Advances in knowledge: HU as a surrogate for bone density may vary significantly in CT ultralow dose imaging. However, use of std kernels and MBIR technology reduce HU error values and may retain the highest CNR. PMID:26859336

  14. Hounsfield units variations: impact on CT-density based conversion tables and their effects on dose distribution.

    Science.gov (United States)

    Zurl, B; Tiefling, R; Winkler, P; Kindl, P; Kapp, K S

    2014-01-01

    Determination of dose error margins in radiation therapy planning due to variations in Hounsfield Units (HU) values dependent on the use of different CT scanning protocols. Based on a series of different CT scanning protocols used in clinical practice, conversion tables for radiation dose calculations were generated and subsequently tested on a phantom. These tables were then used to recalculate the radiation therapy plans of 28 real patients after an incorrect scanning protocol had inadvertently been used for these patients. Different CT parameter settings resulted in errors of HU values of up to 2.6% for densities of 1.1 g/cm(3). The largest errors were associated with changes in the tube voltage. Tests on a virtual water phantom with layers of variable thickness and density revealed a sawtooth-shaped curve for the increase of dose differences from 0.3 to 0.6% and 1.5% at layer thicknesses of 1, 3, and 7 cm, respectively. Use of a beam hardening filter resulted in a reference dose difference of 0.6% in response to a density change of 5%. The recalculation of data from 28 patients who received radiation therapy to the head revealed an overdose of 1.3 ± 0.4% to the bone and 0.7 ± 0.1% to brain tissue. On average, therefore, one monitor unit (range 0-3 MU) per 100 MU more than the correct dose had been given. Use of different CT scanning protocols leads to variations of up to 20% in the HU values. This can result in a mean systematic dose error of 1.5%. Specific conversion tables and automatic CT scanning protocol recognition could reduce dose errors of these types.

  15. Radiation Dose Effects into LCO in Technical Specification by Iodine in Hanul units 1,2

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hye Min; Lee, Seung Chan [KHNP Central Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    This study estimates the impact of the 1-th coolant system in NPP to the LCO (Limiting Condition of Operation) limits which is in the site boundary. Dose limit is merged into the effective dose from whole body and thyroid dose limits, that is possible to combine the two LCOs to a unified LCO. To estimate the limits, the radiation dose of one of the designed accidents should be chosen to check the radiation dose response. The selected accident is based on Seung Chan Lee's study at KHNP in 2011. Using the selected accident, Iodine dose effect is reviewed depending on the LCO limiting responsibility and the specific behavior. In order to evaluate the radiation dose effect in Technical Specification of Hanul 1,2, SGTR is selected for some sensitivity analysis. From the results, in Hanul site, the case of LOOP plus ADV plus GIS is the most severe case and the dose limit margin is about 110% in LCO.

  16. The mean active bone marrow dose to the adult population of the United States from diagnostic radiology

    International Nuclear Information System (INIS)

    Shleien, B.; Tucker, T.T.; Johnson, D.W.

    1977-01-01

    Estimates, based on an empirical model and computer program, have been calculated and are presented on the mean active bone marrow dose to adults from diagnostic radiography, fluoroscopy, and dental radiography as practiced in the United States in 1970. The annual per capita mean active bone marrow dose in 1970 to adults from the above practices is estimated to be 103 mrad; 77 percent, 20 percent, and 3 percent from radiographic, fluoroscopic and dental examinations respectively. Examinations of the upper and lower abdomen contribute approximately 39 percent each to the total mean active bone marrow dose for adults; those of the pelvis 4 percent; the thorax 12 percent; and head and neck examinations (including dental) contribute about 6 percent. The per capita mean active bone marrow dose for various age groups is discussed. Contributions to the dose within a given age group from different examinations indicate that in the 15-34 year old age group Lumbar and Lumbosacral Spine examinations contribute most to the mean active bone marrow dose. Thereafter Upper G I Series and Barium Enemas are the highest contributors. Comparisons are made with results of the 1964 U.S. X-ray survey and similar surveys from other nations

  17. Radiation dose measurements of an on-board imager X-ray unit using optically-stimulated luminescence dosimeters

    International Nuclear Information System (INIS)

    Smith, Leon; Haque, Mamoon; Hill, Robin; Morales, Johnny

    2015-01-01

    Cone beam computed tomography (CBCT) is now widely used to image radiotherapy patients prior to treatment for the purpose of accurate patient setup. However each CBCT image delivered to a patient increases the total radiation dose that they receive. The measurement of the dose delivered from the CBCT images is not readily performed in the clinic. In this study, we have used commercially available optically stimulated luminescence (OSLD) dosimeters to measure the dose delivered by the Varian OBI on a radiotherapy linear accelerator. Calibration of the OSLDs was achieved by using a therapeutic X-ray unit. The dose delivered by a head CBCT scan was found to be 3.2 ± 0.3 mGy which is similar in magnitude to the dose of a head computed tomography (CT) scan. The results of this study suggest that the radiation hazard associated with CBCT is of a similar nature to that of conventional CT scans. We have also demonstrated that the OSLDs are suitable for these low X-ray dose measurements.

  18. Effective dose per unit kerma-area product conversion factors in adults undergoing modified barium swallow studies

    International Nuclear Information System (INIS)

    Shaw Bonilha, Heather; Wilmskoetter, Janina; Tipnis, Sameer V.; Martin-Harris, Bonnie; Huda, Walter

    2017-01-01

    This study presents an investigation of adult effective dose (E) per unit Kerma-Area Product (KAP) in Modified Barium Swallow Study (MBSS) examinations. PC program for X-ray Monte Carlo (version 2.0.1) was used to calculate patient organ doses during MBSS examinations, which used combined to generate effective dose. Normalized patient doses were obtained by dividing the effective dose (mSv) by the incident KAP (Gy.cm 2 ). Five standard projections were studied and the importance of X-ray beam size and in patient size (body mass index) were investigated. Lateral projections had an average E/ KAP conversion factor of 0.19 ± 0.04 mSv/Gy.cm 2 . The average E/KAP was highest for upper gastrointestinal (GI) anterior- posterior projections (0.27 ± 0.04 mSv/Gy.cm 2 ) and lowest for upper GI posterior-anterior projections (0.09 ± 0.03 mSv/ Gy.cm 2 ). E/KAP always increased with increasing filtration and/or X-ray tube voltage. Reducing the X-ray beam cross-sectional area increased the E/KAP conversion factors. Small patients have the E/KAP conversion factors that are twice those of a standard adult. Conversion factors for effective dose of adult patients undergoing MBSS examinations must account for X-ray beam projection, beam quality (kV and filtration), image size and patient size. (authors)

  19. Terms and definitions in the field of radiological technique. Dose quantities and units. Draft. Begriffe und Benennungen in der radiologischen Technik. Dosisgroessen und Dosiseinheiten. Entwurf

    Energy Technology Data Exchange (ETDEWEB)

    1977-11-01

    This draft standard contains the definitions of the terms, quantities, and units important in dosimetry, while the methods of measurement and calculation are dealt with in other standards. Other than the standard of June 1972, this revised draft standard introduces the SI units of the energy dose, the Gray, and of the activity of a radioactive substance, the Becquerel. Important new measuring quantities are the standard energy dose and the dose equivalent index. The terms local dose and personnel dose are redefined in agreement with the Radiation Protection Ordinance of October 13, 1976.

  20. Terms and definitions in the field of radiological technique. Dose quantities and units. Draft. Begriffe und Benennungen in der radiologischen Technik. Dosisgroessen und Dosiseinheiten. Entwurf

    Energy Technology Data Exchange (ETDEWEB)

    1977-11-01

    The standard contains the definitions of terms, quantities and units important in dosimetry, while other standards deal with the measurement and calculation methods. As against the June 1972 edition, this amended standard introduces the SI units of the energy dose, the Gray (Gy), and of the activity of a radioactive substance, the Becquerel (Bq). Important new measuring quantities are the standard energy dose and the equivalent dose index. The terms local dose and personnel dose are redefined in accordance with the Radiation Protection Ordinance of Oct. 13th, 1976.

  1. Measurement of MV CT dose index for Hi-ART helical tomotherapy unit

    International Nuclear Information System (INIS)

    Wang Yunlai; Liao Xiongfei

    2010-01-01

    Objective: To evaluate the patient dose from Hi-ART MV helical CT imaging in image-guided radiotherapy. Methods: Weighted CT dose index (CTDI W ) was measured with PTW TM30009 CT ion chamber in head and body phantoms, respectively,for slice thicknesses of 2, 4, 6 mm with scanned range of 5 cm and 15 cm. Dose length products (DLP) were subsequently calculated. The CTDI W and DLP were compared with XVI kV CBCT and ACQSim simulator CT for routine clinical protocols. Results: An inverse relationship between CTDI and the slice thickness was found. The dose distribution was inhomogeneous owing to the attenuation of the couch. CTDI and DLP had close relationship with the slice thickness and the scanned range. Patient dose from MVCT was lower than XVI CBCT for head, but larger for body scan. Conclusions: CTDI W can be used to assess the patient dose in MV helical CT due to its simplicity for measurement and reproducibility. Regular measurement should be performed in QA and QC program. Appropriate slice thickness and scan range should be chosen to reduce the patient dose. (authors)

  2. Exposure Scenarios and Unit Dose Factors for the Hanford Immobilized Low Activity Tank Waste Performance Assessment

    Energy Technology Data Exchange (ETDEWEB)

    RITTMANN, P.D.

    1999-12-29

    Exposure scenarios are defined to identify potential pathways and combinations of pathways that could lead to radiation exposure from immobilized tank waste. Appropriate data and models are selected to permit calculation of dose factors for each exposure

  3. Size-appropriate radiation doses in pediatric body CT: a study of regional community adoption in the United States

    International Nuclear Information System (INIS)

    Hopkins, Katharine L.; Vajtai, Petra L.; Pettersson, David R.; Spinning, Kristopher; Beckett, Brooke R.; Koudelka, Caroline W.; Bardo, Dianna M.E.

    2013-01-01

    During the last decade, there has been a movement in the United States toward utilizing size-appropriate radiation doses for pediatric body CT, with smaller doses given to smaller patients. This study assesses community adoption of size-appropriate pediatric CT techniques. Size-specific dose estimates (SSDE) in pediatric body scans are compared between community facilities and a university children's hospital that tailors CT protocols to patient size as advocated by Image Gently. We compared 164 pediatric body scans done at community facilities (group X) with 466 children's hospital scans. Children's hospital scans were divided into two groups: A, 250 performed with established pediatric weight-based protocols and filtered back projection; B, 216 performed with addition of iterative reconstruction technique and a 60% reduction in volume CT dose index (CTDI vol ). SSDE was calculated and differences among groups were compared by regression analysis. Mean SSDE was 1.6 and 3.9 times higher in group X than in groups A and B and 2.5 times higher for group A than group B. A model adjusting for confounders confirmed significant differences between group pairs. Regional community hospitals and imaging centers have not universally adopted child-sized pediatric CT practices. More education and accountability may be necessary to achieve widespread implementation. Since even lower radiation doses are possible with iterative reconstruction technique than with filtered back projection alone, further exploration of the former is encouraged. (orig.)

  4. Pharyngeal and cervical cancer incidences significantly correlate with personal UV doses among whites in the United States.

    Science.gov (United States)

    Godar, Dianne E; Tang, Rong; Merrill, Stephen J

    2014-09-01

    Because we found UV-exposed oral tissue cells have reduced DNA repair and apoptotic cell death compared with skin tissue cells, we asked if a correlation existed between personal UV dose and the incidences of oral and pharyngeal cancer in the United States. We analyzed the International Agency for Research on Cancer's incidence data for oral and pharyngeal cancers by race (white and black) and sex using each state's average annual personal UV dose. We refer to our data as 'white' rather than 'Caucasian,' which is a specific subgroup of whites, and 'black' rather than African-American because blacks from other countries around the world reside in the U.S. Most oropharyngeal carcinomas harboured human papilloma virus (HPV), so we included cervical cancer as a control for direct UV activation. We found significant correlations between increasing UV dose and pharyngeal cancer in white males (p=0.000808) and females (p=0.0031) but not in blacks. Shockingly, we also found cervical cancer in whites to significantly correlate with increasing UV dose (p=0.0154). Thus, because pharyngeal and cervical cancer correlate significantly with increasing personal UV dose in only the white population, both direct (DNA damage) and indirect (soluble factors) effects may increase the risk of HPV-associated cancer. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  5. Size-appropriate radiation doses in pediatric body CT: a study of regional community adoption in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, Katharine L.; Vajtai, Petra L. [Oregon Health and Science University, Department of Diagnostic Radiology, DC7R, Portland, OR (United States); Oregon Health and Science University, Department of Pediatrics, Portland, OR (United States); Pettersson, David R.; Spinning, Kristopher; Beckett, Brooke R. [Oregon Health and Science University, Department of Diagnostic Radiology, DC7R, Portland, OR (United States); Koudelka, Caroline W. [Oregon Health and Science University, Division of Biostatistics, Department of Public Health and Preventive Medicine, Portland, OR (United States); Bardo, Dianna M.E. [Oregon Health and Science University, Department of Diagnostic Radiology, DC7R, Portland, OR (United States); Oregon Health and Science University, Department of Cardiovascular Medicine, Portland, OR (United States)

    2013-09-15

    During the last decade, there has been a movement in the United States toward utilizing size-appropriate radiation doses for pediatric body CT, with smaller doses given to smaller patients. This study assesses community adoption of size-appropriate pediatric CT techniques. Size-specific dose estimates (SSDE) in pediatric body scans are compared between community facilities and a university children's hospital that tailors CT protocols to patient size as advocated by Image Gently. We compared 164 pediatric body scans done at community facilities (group X) with 466 children's hospital scans. Children's hospital scans were divided into two groups: A, 250 performed with established pediatric weight-based protocols and filtered back projection; B, 216 performed with addition of iterative reconstruction technique and a 60% reduction in volume CT dose index (CTDI{sub vol}). SSDE was calculated and differences among groups were compared by regression analysis. Mean SSDE was 1.6 and 3.9 times higher in group X than in groups A and B and 2.5 times higher for group A than group B. A model adjusting for confounders confirmed significant differences between group pairs. Regional community hospitals and imaging centers have not universally adopted child-sized pediatric CT practices. More education and accountability may be necessary to achieve widespread implementation. Since even lower radiation doses are possible with iterative reconstruction technique than with filtered back projection alone, further exploration of the former is encouraged. (orig.)

  6. United States-assisted studies on dose reconstruction in the former Soviet Union

    International Nuclear Information System (INIS)

    Anspaugh, L.R.; Bouville, A.

    1995-12-01

    Following the Chernobyl accident, the US and the USSR entered into an agreement to work on the safety of civilian nuclear reactors; one aspect of that work was to study the environmental transport and health effects of radionuclides released by the accident. After the break-up of the USSR separate agreements were established between the US and Ukraine, Belarus, and Russia to continue work on dose reconstruction and epidemiologic studies of health effects from exposure to external radiation and the incorporation of radionuclides. Studies in Belarus and Ukraine related to the Chernobyl accident now emphasize epidemiologic: studies of childhood-thyroid cancer and leukemia, and eye-lens-cataract formation in liquidators. Supporting studies on dose reconstruction emphasize a variety of ecological, physical, and biological techniques. Studies being conducted in Russia currently emphasize health effects in the workers and the population around the Mayak Industrial Association. As this production complex is an analogue of the US Hanford Works, advantage is being taken of the US experience in conducting a similar, recently completed dose-reconstruction study. In all cases the primary work on dose reconstruction is being performed by scientists from the former Soviet Union. US assistance is in the form of expert consultation and participation, exchange visits, provision of supplies and equipment, and other forms of local assistance

  7. Case Study of High-Dose Ketamine for Treatment of Complex Regional Pain Syndrome in the Pediatric Intensive Care Unit.

    Science.gov (United States)

    Pasek, Tracy Ann; Crowley, Kelli; Campese, Catherine; Lauer, Rachel; Yang, Charles

    2017-06-01

    Complex regional pain syndrome (CRPS) is a life-altering and debilitating chronic pain condition. The authors are presenting a case study of a female who received high-dose ketamine for the management of her CRPS. The innovative treatment lies not only within the pharmacologic management of her pain, but also in the fact that she was the first patient to be admitted to our pediatric intensive care unit solely for pain control. The primary component of the pharmacotherapy treatment strategy plan was escalating-dose ketamine infusion via patient-controlled-analgesia approved by the pharmacy and therapeutics committee guided therapy for this patient. The expertise of advanced practice nurses blended exquisitely to ensure patient and family-centered care and the coordination of care across the illness trajectory. The patient experienced positive outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Production of humoral factors that stimulate spleen colony-forming units in mice irradiated with moderate doses of X rays

    International Nuclear Information System (INIS)

    Grande, T.; Gonzalez, J.; Tejero, C.; Maganto, G.; Bueren, J.A.

    1990-01-01

    The production of humoral factors that stimulate spleen colony-forming units (CFU-S) has been studied in irradiated mice using an in vivo diffusion chamber assay. The experiments show that a significant release of factors that stimulate CFU-S takes place in the first few days after irradiation with moderate doses of 1.5 or 5 Gy. In contrast, the release of significant amounts of these humoral factors was not seen in animals irradiated with either low (0.75 Gy) or high (10 Gy) doses of X rays. The correlation observed between the production of factors that stimulate the CFU-S and the hemopoietic regeneration kinetics of the irradiated mice suggests that these factors represent part of the physiological regulators controlling the proliferation of CFU-S

  9. Population characteristics and absorbed dose to the population from nuclear medicine: United States--1982

    International Nuclear Information System (INIS)

    Mettler, F.A. Jr.; Christie, J.H.; Williams, A.G. Jr.; Moseley, R.D. Jr.; Kelsey, C.A.

    1986-01-01

    Those in the U.S. population who receive nuclear medicine examinations have been characterized by age and sex. Males received 42% of examinations while females received 58%. More than one-third of the examinations were done on persons older than 64 y of age and more than two-thirds on patients older than 45 y of age. The per caput effective dose equivalent from nuclear medicine procedures in 1982 was 140 muSv (14 mrem); whereas, the per caput age-specific effective dose equivalent to the U.S. population was 50 muSv (5.9 mrem). These can be compared with 2 mSv (200 mrem) from natural background

  10. Significance of studies of low-dose radiation fallout in the western United States

    International Nuclear Information System (INIS)

    Rothman, K.J.

    1984-01-01

    The sum of evidence from these studies about the effects of nuclear testing is extremely modest. Lack of good dose information precluded any valuable scientific conclusions. The evidence indicating excesses of leukemia incidence beyond what would already be accepted as the leukemogenic effect of ionizing radiation is fragile. Similarly, the evidence presumed to indicate the absence of thyroid effects is unpersuasive, actually showing a weak but positive effect

  11. Pharmacokinetics of Imipenem/Cilastatin Burn Intensive Care Unit Patients Undergoing High-Dose Continuous Venovenous Hemofiltration.

    Science.gov (United States)

    Boucher, Bradley A; Hudson, Joanna Q; Hill, David M; Swanson, Joseph M; Wood, G Christopher; Laizure, S Casey; Arnold-Ross, Angela; Hu, Zhe-Yi; Hickerson, William L

    2016-12-01

    High-dose continuous venovenous hemofiltration (CVVH) is a continuous renal replacement therapy (CRRT) used frequently in patients with burns. However, antibiotic dosing is based on inference from studies assessing substantially different methods of CRRT. To address this knowledge gap for imipenem/cilastatin (I/C), we evaluated the systemic and extracorporeal clearances (CLs) of I/C in patients with burns undergoing high-dose CVVH. Prospective clinical pharmacokinetic study. Ten adult patients with burns receiving I/C for a documented infection and requiring high-dose CVVH were studied. Blood and effluent samples for analysis of I/C concentrations were collected for up to 6 hours after the I/C infusion for calculation of I/C total CL (CL T otal ), CL by CVVH (CL HF ), half-life during CVVH, volume of distribution at steady state (Vd ss ), and the percentage of drug eliminated by CVVH. In this patient sample, the mean age was 50 ± 17 years, total body surface area burns was 23 ± 27%, and 80% were male. Nine patients were treated with high-dose CVVH for acute kidney injury and one patient for sepsis. The mean delivered CVVH dose was 52 ± 14 ml/kg/hour (range 32-74 ml/kg/hr). The imipenem CL HF was 3.27 ± 0.48 L/hour, which accounted for 23 ± 4% of the CL T otal (14.74 ± 4.75 L/hr). Cilastatin CL HF was 1.98 ± 0.56 L/hour, which accounted for 45 ± 19% of the CL T otal (5.16 + 2.44 L/hr). The imipenem and cilastatin half-lives were 1.77 ± 0.38 hours and 4.21 ± 2.31 hours, respectively. Imipenem and cilastatin Vd ss were 35.1 ± 10.3 and 32.8 ± 13.8 L, respectively. Efficient removal of I/C by high-dose CVVH, a high overall clearance, and a high volume of distribution in burn intensive care unit patients undergoing this CRRT method warrant aggressive dosing to treat serious infections effectively depending on the infection site and/or pathogen. © 2016 Pharmacotherapy Publications, Inc.

  12. Changes in the levels of radioactive fall-out and the resulting radiation doses to man in the United Kingdom

    International Nuclear Information System (INIS)

    Loutit, J.F.; Marley, W.G.; Mayneord, W.V.; Russell, R.S.

    1960-01-01

    In the period covered by the Council's 1956 report, that is, up to the spring of 1956, the radioactive debris falling in the United Kingdom had arisen from a large number of small nuclear explosions, chiefly in Nevada, and from a few large nuclear explosions mainly in the Pacific, especially in March, 1954. It was recognized that the doses of radiation to persons from the deposition of debris arising from the smaller nuclear explosions would be far outweighed by those from the larger explosions. The material reaching the U.K. from the latter at that time was found to have an apparent age (determined from the ratio of strontium 89 to strontium 90 which ranged from 7 to 14 months. In these circumstances the dose contributed by the isotopes of relatively short life (say, two months or less) was much less important than the dose from the long-lived isotopes such as caesium 137 and strontium 90. From the autumn of 1956 the pattern of testing changed. A high proportion of the explosions carried out were of megaton size and took place in higher latitudes in the northern hemisphere. As a result the short-lived isotopes became relatively more important and, with the heavy testing of nuclear devices in the Arctic in October, 1958, the contribution of radioactive fall-out to the background dose-rate in air in the open rose in the spring of 1959 so that, for a period of a month or two, it amounted to some 30 per cent of the natural background. This rise in dose-rate can be attributed to two main causes, namely, the increase in the rate of testing and the shorter time during which the fission products from the tests in the autumn in northern latitudes, particularly in the Arctic, have remained airborne

  13. Changes in the levels of radioactive fall-out and the resulting radiation doses to man in the United Kingdom

    Energy Technology Data Exchange (ETDEWEB)

    Loutit, J F; Marley, W G; Mayneord, W V; Russell, R S

    1960-12-01

    In the period covered by the Council's 1956 report, that is, up to the spring of 1956, the radioactive debris falling in the United Kingdom had arisen from a large number of small nuclear explosions, chiefly in Nevada, and from a few large nuclear explosions mainly in the Pacific, especially in March, 1954. It was recognized that the doses of radiation to persons from the deposition of debris arising from the smaller nuclear explosions would be far outweighed by those from the larger explosions. The material reaching the U.K. from the latter at that time was found to have an apparent age (determined from the ratio of strontium 89 to strontium 90 which ranged from 7 to 14 months. In these circumstances the dose contributed by the isotopes of relatively short life (say, two months or less) was much less important than the dose from the long-lived isotopes such as caesium 137 and strontium 90. From the autumn of 1956 the pattern of testing changed. A high proportion of the explosions carried out were of megaton size and took place in higher latitudes in the northern hemisphere. As a result the short-lived isotopes became relatively more important and, with the heavy testing of nuclear devices in the Arctic in October, 1958, the contribution of radioactive fall-out to the background dose-rate in air in the open rose in the spring of 1959 so that, for a period of a month or two, it amounted to some 30 per cent of the natural background. This rise in dose-rate can be attributed to two main causes, namely, the increase in the rate of testing and the shorter time during which the fission products from the tests in the autumn in northern latitudes, particularly in the Arctic, have remained airborne.

  14. UARS PEM Level 2 AXIS 2 V001 (UARPE2AXIS2) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The UARS Particle Environment Monitor (PEM) level 2 Atmosphere X-Ray Imaging Spectrometer (AXIS) unit 2 daily product contains the X-ray high-resolution spectral...

  15. UARS PEM Level 2 AXIS 1 V001 (UARPE2AXIS1) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The UARS Particle Environment Monitor (PEM) level 2 Atmosphere X-Ray Imaging Spectrometer (AXIS) unit 1 daily product contains the X-ray high-resolution spectral...

  16. Infectious Dose of Listeria monocytogenes in Outbreak Linked to Ice Cream, United States, 2015.

    Science.gov (United States)

    Pouillot, Régis; Klontz, Karl C; Chen, Yi; Burall, Laurel S; Macarisin, Dumitru; Doyle, Matthew; Bally, Kären M; Strain, Errol; Datta, Atin R; Hammack, Thomas S; Van Doren, Jane M

    2016-12-01

    The relationship between the number of ingested Listeria monocytogenes cells in food and the likelihood of developing listeriosis is not well understood. Data from an outbreak of listeriosis linked to milkshakes made from ice cream produced in 1 factory showed that contaminated products were distributed widely to the public without any reported cases, except for 4 cases of severe illness in persons who were highly susceptible. The ingestion of high doses of L. monocytogenes by these patients infected through milkshakes was unlikely if possible additional contamination associated with the preparation of the milkshake is ruled out. This outbreak illustrated that the vast majority of the population did not become ill after ingesting a low level of L. monocytogenes but raises the question of listeriosis cases in highly susceptible persons after distribution of low-level contaminated products that did not support the growth of this pathogen.

  17. Predicting Pulmonary O2 Toxicity: A New Look at the Unit Pulmonary Toxicity Dose

    Science.gov (United States)

    1985-05-01

    beatl loeged# aNy ahepes in Vo was considered error. The assumptieo was shoe eapeova to a 10 below the "safe’! I02 should have produced se daeromeat...Naval Medical Research Institute SethesdolMO 20814-505b NMRI 86-52 December 1986 PREDICTING4 PULMONARY 0 2 TOXICITY: j k,, NEW LOOK AT THE UNIT...distribution is unlimited °Q0- C(-" Naval Medical Research LLj and Development Command ,, J Bethesda, Maryland 20814-5044 -4 • Department of the Navy Naval

  18. Obesity in the United States—dysbiosis from exposure to low-dose antibiotics?

    Directory of Open Access Journals (Sweden)

    Lee W Riley

    2013-12-01

    Full Text Available The rapid increase in obesity prevalence in the United States in the last 20 years is unprecedented and not well explained. Here, we explore a hypothesis that the obesity epidemic may be driven by population-wide chronic exposures to low-residue antibiotics that have increasingly entered the American food chain over the same time period. We propose this hypothesis based on two recent bodies of published reports—1 those that provide evidence for the spread of antibiotics into the American food chain, and 2 those that examine the relationship between the gut microbiota and body physiology. The livestock use of antimicrobial agents has sharply increased in the US over the same 20-year period of the obesity epidemic, especially with the expansion of intensified livestock production, such as the concentrated animal feeding operations (CAFOs. Observational and experimental studies support the idea that changes in the intestinal microbiota exert a profound effect on body physiology. We propose that chronic exposures to low-residue antimicrobial drugs in food could disrupt the equilibrium state of intestinal microbiota and cause dysbiosis that can contribute to changes in body physiology. The obesity epidemic in the United States may be partly driven by the mass exposure of Americans to food containing low-residue antimicrobial agents. While this hypothesis cannot discount the impact of diet and other factors associated with obesity, we believe studies are warranted to consider this possible driver of the epidemic.

  19. An Improved Methodology of Monetary Values of the Unit Collective Dose for Intervention Against Long-Term Exposure Following a Nuclear Accident

    International Nuclear Information System (INIS)

    Hwang, Won Tae; Kim, Eun Han; Suh, Kyung Suk; Choi, Young Gil; Han, Moon Hee

    2002-01-01

    A more practice approach for the determination of monetary values of the unit collective dose for intervention against long-term exposure following a nuclear accident was proposed. In addition, the monetary values of the unit collective dose estimated from the proposed approach were compared with those estimated from the previous model, which are derived from assumptions of routine exposure and the same values are applied in a nuclear accident without modification, using Korea economic data. The monetary values based on the proposed approach showed a distinct difference depending on inequity in the distribution of individual doses. The discounting rate was also an important factor in determination of monetary values of the unit collective dose

  20. An Improved Methodology of Monetary Values of the Unit Collective Dose for Intervention Against Long-Term Exposure Following a Nuclear Accident

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Won Tae; Kim, Eun Han; Suh, Kyung Suk; Choi, Young Gil; Han, Moon Hee [KAERI, Daejeon (Korea, Republic of)

    2002-06-15

    A more practice approach for the determination of monetary values of the unit collective dose for intervention against long-term exposure following a nuclear accident was proposed. In addition, the monetary values of the unit collective dose estimated from the proposed approach were compared with those estimated from the previous model, which are derived from assumptions of routine exposure and the same values are applied in a nuclear accident without modification, using Korea economic data. The monetary values based on the proposed approach showed a distinct difference depending on inequity in the distribution of individual doses. The discounting rate was also an important factor in determination of monetary values of the unit collective dose.

  1. Milrinone in advanced heart failure: dose and therapeutic monitor outside intensive care unit.

    Science.gov (United States)

    Charisopoulou, Dafni; Leaver, Neil; Banner, Nicholas R

    2014-04-01

    Advanced chronic heart failure (ACHF) patients often require inotropes before transplantation or ventricular assist device implantation. Milrinone, an inotrope and vasodilator, may accumulate in cardiorenal syndrome with serious adverse effects. We investigated the potential for therapeutic drug monitoring of milrinone levels using High Performance Liquid Chromatography Mass Spectrometry (HPLC-MS). 22 ACHF patients (15 males, 49±9 years) received milrinone 50 µg/kg intravenously (i.v.) during heart catheterization. Milrinone levels were 216±71 ng/ml (within the reported therapeutic range: 100-300 ng/ml), followed by improvements in cardiac index, pulmonary artery and wedge pressures (p milrinone (5-26 days) at 0.1-0.2 µg/kg/min, titrated according to plasma milrinone levels. No adverse events occurred. Therapeutic levels were achieved with doses of 0.2±0.06 µg/Kg/min, below those recommended in Summary of Product Characteristics. Milrinone therapy can be noninvasively monitored by HPLC-MS, while avoiding toxicity in ACHF.

  2. Radiation exposure reduction technologies for a Japanese Advanced BWR (Dose Rate Reduction Experience in Shika Unit 2)

    International Nuclear Information System (INIS)

    Saito, Takeshi; Ichikawa, Koji; Ishimaru, Hiroshi; Aizawa, Motohiro; Sato, Yoshiteru; Morita, Shoichi

    2012-09-01

    Operating experiences of the advanced boiling water reactor (ABWR) have been accumulated in Japan since the first ABWRs Kashiwazaki-Kariwa NPS unit 6 and 7 came into service. Shika NPS unit 2 (Shika-2) of Hokuriku Electric Power Co. is the fourth ABWR plant in Japan. Since ABWRs have no piping of the reactor recirculation system (RRS), which is the largest source of radiation in conventional BWRs, carbon steel piping of the reactor water cleanup system (RWCU) and residual heat removal system (RHR) are the largest source in ABWRs. Therefore we have focused on reduction methods of radioactive material on carbon steel surface in order to reduce the quantity of occupational exposure in Shika-2. In Shika-2 the following methods have been adopted. Before fuel loading, alkaline pre-filming process was applied to the RWCU piping during plant startup testing. After start of operation, the feed water iron concentration control (or nickel/iron ratio control) method was applied. Furthermore, during shutdown operation the RHR system was operated when the reactor water temperature was dropped to 120 degree C with the use of condenser heat sink cooling operation. These dose rate reduction methods worked well in Shika-2 as expected. The quantity of occupational exposure at the 3 rd outage in Shika-2 was approximately 0.35 person-Sv. On the basis of the results obtained thus far, the occupational dose expected at the outage after deposition amount of radioactivity reaching the equilibrium state has been estimated to be around 0.5 person-Sv. This value is considered to be in low level compared with the worldwide statistics. (authors)

  3. Experience with respect to dose limitation in nuclear fuel service operations in the United Kingdom supporting civil nuclear power programmes

    International Nuclear Information System (INIS)

    Kennedy, J.W.

    1983-01-01

    Within the United Kingdom, the nuclear power generation programme is supported by nuclear fuel services including uranium enrichment, fuel fabrication and reprocessing, operated by British Nuclear Fuels Limited (BNFL). These have entailed the processing of large quantities of uranium and of plutonium and fission products arising in the course of irradiation of fuel in nuclear power stations and have necessitated substantial programmes for the radiological protection of the public and of the workers employed in the industry. This paper presents and reviews the statistics of doses recorded in the various sectors of nuclear fuel services operations against the background of the standards to which the industry is required to operate. A description is given of the development of BNFL policy in keeping with the objective of being recognized as among those industries regarded as safe and the resource implications of measures to reduce doses received by workers are reviewed in the light of experience. Finally, the paper reviews the epidemiological data which have been, and continue to be, collected for workers who have been employed in these nuclear fuel services. (author)

  4. Patient Dose From Megavoltage Computed Tomography Imaging

    International Nuclear Information System (INIS)

    Shah, Amish P.; Langen, Katja M.; Ruchala, Kenneth J.; Cox, Andrea; Kupelian, Patrick A.; Meeks, Sanford L.

    2008-01-01

    Purpose: Megavoltage computed tomography (MVCT) can be used daily for imaging with a helical tomotherapy unit for patient alignment before treatment delivery. The purpose of this investigation was to show that the MVCT dose can be computed in phantoms, and further, that the dose can be reported for actual patients from MVCT on a helical tomotherapy unit. Methods and Materials: An MVCT beam model was commissioned and verified through a series of absorbed dose measurements in phantoms. This model was then used to retrospectively calculate the imaging doses to the patients. The MVCT dose was computed for five clinical cases: prostate, breast, head/neck, lung, and craniospinal axis. Results: Validation measurements in phantoms verified that the computed dose can be reported to within 5% of the measured dose delivered at the helical tomotherapy unit. The imaging dose scaled inversely with changes to the CT pitch. Relative to a normal pitch of 2.0, the organ dose can be scaled by 0.67 and 2.0 for scans done with a pitch of 3.0 and 1.0, respectively. Typical doses were in the range of 1.0-2.0 cGy, if imaged with a normal pitch. The maximal organ dose calculated was 3.6 cGy in the neck region of the craniospinal patient, if imaged with a pitch of 1.0. Conclusion: Calculation of the MVCT dose has shown that the typical imaging dose is approximately 1.5 cGy per image. The uniform MVCT dose delivered using helical tomotherapy is greatest when the anatomic thickness is the smallest and the pitch is set to the lowest value

  5. Cobalt-60 total body irradiation dosimetry at 220 cm source-axis distance

    International Nuclear Information System (INIS)

    Glasgow, G.P.; Mill, W.B.

    1980-01-01

    Adults with acute leukemia are treated with cyclophosphamide and total body irradiation (TBI) followed by autologous marrow transplants. For TBI, patients seated in a stand angled 45 0 above the floor are treated for about 2 hours at 220 cm source-axis distance (SAD) with sequential right and left lateral 87 cm x 87 cm fields to a 900 rad mid-pelvic dose at about 8 rad/min using a 5000 Ci cobalt unit. Maximum (lateral) to minimum (mid-plane) dose ratios are: hips--1.15, shoulders--1.30, and head--1.05, which is shielded by a compensator filter. Organ doses are small intestine, liver and kidneys--1100 rad, lung--1100 to 1200 rad, and heart--1300 rad. Verification dosimetry reveals the prescribed dose is delivered to within +-5%. Details of the dosimetry of this treatment are presented

  6. Prolonged high-dose intravenous magnesium therapy for severe tetanus in the intensive care unit: a case series

    Directory of Open Access Journals (Sweden)

    Fligou Fotini

    2010-03-01

    Full Text Available Abstract Introduction Tetanus rarely occurs in developed countries, but it can result in fatal complications including respiratory failure due to generalized muscle spasms. Magnesium infusion has been used to treat spasticity in tetanus, and its effectiveness is supported by several case reports and a recent randomized controlled trial. Case presentations Three Caucasian Greek men aged 30, 50 and 77 years old were diagnosed with tetanus and admitted to a general 12-bed intensive care unit in 2006 and 2007 for respiratory failure due to generalized spasticity. Intensive care unit treatment included antibiotics, hydration, enteral nutrition, early tracheostomy and mechanical ventilation. Intravenous magnesium therapy controlled spasticity without the need for additional muscle relaxants. Their medications were continued for up to 26 days, and adjusted as needed to control spasticity. Plasma magnesium levels, which were measured twice a day, remained in the 3 to 4.5 mmol/L range. We did not observe hemodynamic instability, arrhythmias or other complications related to magnesium therapy in these patients. All patients improved, came off mechanical ventilation, and were discharged from the intensive care unit in a stable condition. Conclusion In comparison with previous reports, our case series contributes the following meaningful additional information: intravenous magnesium therapy was used on patients already requiring mechanical ventilation and remained effective for up to 26 days (significantly longer than in previous reports without significant toxicity in two patients. The overall outcome was good in all our patients. However, the optimal dose, optimal duration and maximum safe duration of intravenous magnesium therapy are unknown. Therefore, until more data on the safety and efficacy of magnesium therapy are available, its use should be limited to carefully selected tetanus cases.

  7. Survey of doses and frequency of X-ray examinations on children at the intensive care unit of a large reference pediatric hospital

    International Nuclear Information System (INIS)

    Pedrosa de Azevedo, Ana Cecilia; Osibote, Adelaja Otolorin; Bastos Boechat, Marcia Cristina

    2006-01-01

    Objective: This work aims to evaluate the entrance surface dose (ESD), the body organ dose (BOD) and the effective dose (E) resulting from pediatric radiological procedures with the use of portable X-ray equipments. Materials and methods: The software DoseCal was used to evaluate the doses imparted to patients. The children were classified according to their weight and age groups, and the study included three sectors of the intensive care unit of a large reference pediatric hospital in Rio de Janeiro. Results: A total of 518 radiographs have been performed (424 for chest and 94 for abdomen). The statistical data were compared with previously published results. The BOD is presented for the most exposed organs. Conclusion: The mean value of ESD and E varied widely among neonates. The highest number of radiographs per infant peaked 33 for chest examination in the age group 0-1 year

  8. Intra-individual diagnostic image quality and organ-specific-radiation dose comparison between spiral cCT with iterative image reconstruction and z-axis automated tube current modulation and sequential cCT

    Directory of Open Access Journals (Sweden)

    Holger Wenz

    2016-01-01

    Conclusions: Spiral cCT combined with ATCM and IR allows for significant-radiation dose reduction including a reduce eye lens organ-dose when compared to a tilted sequential cCT while improving subjective and objective image quality.

  9. SU-C-BRC-01: A Monte Carlo Study of Out-Of-Field Doses From Cobalt-60 Teletherapy Units Intended for Historical Correlations of Dose to Normal Tissue

    Energy Technology Data Exchange (ETDEWEB)

    Petroccia, H [University of Florida, Gainesville, FL (United States); Olguin, E [Gainesville, FL (United States); Culberson, W [University of Wisconsin Madison, Madison, WI (United States); Bednarz, B [University of Wisconsin, Madison, WI (United States); Mendenhall, N [UF Health Proton Therapy Institute, Jacksonville, FL (United States); Bolch, W [University Florida, Gainesville, FL (United States)

    2016-06-15

    Purpose: Innovations in radiotherapy treatments, such as dynamic IMRT, VMAT, and SBRT/SRS, result in larger proportions of low-dose regions where normal tissues are exposed to low doses levels. Low doses of radiation have been linked to secondary cancers and cardiac toxicities. The AAPM TG Committee No.158 entitled, ‘Measurements and Calculations of Doses outside the Treatment Volume from External-Beam Radiation Therapy’, has been formed to review the dosimetry of non-target and out-of-field exposures using experimental and computational approaches. Studies on historical patients can provide comprehensive information about secondary effects from out-of-field doses when combined with long-term patient follow-up, thus providing significant insight into projecting future outcomes of patients undergoing modern-day treatments. Methods: We present a Monte Carlo model of a Theratron-1000 cobalt-60 teletherapy unit, which historically treated patients at the University of Florida, as a means of determining doses located outside the primary beam. Experimental data for a similar Theratron-1000 was obtained at the University of Wisconsin’s ADCL to benchmark the model for out-of-field dosimetry. An Exradin A12 ion chamber and TLD100 chips were used to measure doses in an extended water phantom to 60 cm outside the primary field at 5 and 10 cm depths. Results: Comparison between simulated and experimental measurements of PDDs and lateral profiles show good agreement for in-field and out-of-field doses. At 10 cm away from the edge of a 6×6, 10×10, and 20×20 cm2 field, relative out-of-field doses were measured in the range of 0.5% to 3% of the dose measured at 5 cm depth along the CAX. Conclusion: Out-of-field doses can be as high as 90 to 180 cGy assuming historical prescription doses of 30 to 60 Gy and should be considered when correlating late effects with normal tissue dose.

  10. Space/Flight Operable Miniature Six Axis Transducer, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — FUTEK will fully design and manufacture a sensor capable of measuring forces in and about each axis. The unit will measure forces up to 300 Newton's in the principle...

  11. UARS PEM Level 2 AXIS 1 V001

    Data.gov (United States)

    National Aeronautics and Space Administration — The UARS Particle Environment Monitor (PEM) level 2 Atmosphere X-Ray Imaging Spectrometer (AXIS) unit 1 daily product contains the X-ray high-resolution spectral...

  12. UARS PEM Level 2 AXIS 2 V001

    Data.gov (United States)

    National Aeronautics and Space Administration — The UARS Particle Environment Monitor (PEM) level 2 Atmosphere X-Ray Imaging Spectrometer (AXIS) unit 2 daily product contains the X-ray high-resolution spectral...

  13. Triple axis spectrometers

    International Nuclear Information System (INIS)

    Clausen, K.N.

    1997-01-01

    Conventional triple-axis neutron spectroscopy was developed by Brockhouse over thirty years ago' and remains today a versatile and powerful tool for probing the dynamics of condensed matter. The original design of the triple axis spectrometer is technically simple and probes momentum and energy space on a point-by-point basis. This ability to systematically probe the scattering function in a way which only requires a few angles to be moved under computer control and where the observed data in general can be analysed using a pencil and graph paper or a simple fitting routine, has been essential for the success of the method. These constraints were quite reasonable at the time the technique was developed. Advances in computer based data acquisition, neutron beam optics, and position sensitive area detectors have been gradually implemented on many triple axis spectrometer spectrometers, but the full potential of this has not been fully exploited yet. Further improvement in terms of efficiency (beyond point by point inspection) and increased sensitivity (use of focusing optics whenever the problem allows it) could easily be up to a factor of 10-20 over present instruments for many problems at a cost which is negligible compared to that of increasing the flux of the source. The real cost will be in complexity - finding the optimal set-up for a given scan and interpreting the data as the they are taken. On-line transformation of the data for an appropriate display in Q, ω space and analysis tools will be equally important for this task, and the success of these new ideas will crucially depend on how well we solve these problems. (author)

  14. Vertical axis wind turbines

    Science.gov (United States)

    Krivcov, Vladimir [Miass, RU; Krivospitski, Vladimir [Miass, RU; Maksimov, Vasili [Miass, RU; Halstead, Richard [Rohnert Park, CA; Grahov, Jurij [Miass, RU

    2011-03-08

    A vertical axis wind turbine is described. The wind turbine can include a top ring, a middle ring and a lower ring, wherein a plurality of vertical airfoils are disposed between the rings. For example, three vertical airfoils can be attached between the upper ring and the middle ring. In addition, three more vertical airfoils can be attached between the lower ring and the middle ring. When wind contacts the vertically arranged airfoils the rings begin to spin. By connecting the rings to a center pole which spins an alternator, electricity can be generated from wind.

  15. Vertical axis wind turbine

    International Nuclear Information System (INIS)

    Obretenov, V.; Tsalov, T.; Chakarov, T.

    2012-01-01

    In recent years, the interest in wind turbines with vertical axis noticeably increased. They have some important advantages: low cost, relatively simple structure, reliable packaging system of wind aggregate long period during which require no maintenance, low noise, independence of wind direction, etc.. The relatively low efficiency, however, makes them applicable mainly for small facilities. The work presents a methodology and software for approximately aerodynamic design of wind turbines of this type, and also analyzed the possibility of improving the efficiency of their workflow

  16. Amikacin Dosing and Monitoring in Spinal Cord Injury Patients: Variation in Clinical Practice Between Spinal Injury Units and Differences in Experts' Recommendations

    Directory of Open Access Journals (Sweden)

    Subramanian Vaidyanathan

    2006-01-01

    Full Text Available The objective of this article was to determine the current practice on amikacin dosing and monitoring in spinal cord injury patients from spinal cord physicians and experts. Physicians from spinal units and clinical pharmacologists were asked to provide protocol for dosing and monitoring of amikacin therapy in spinal cord injury patients. In a spinal unit in Poland, amikacin is administered usually 0.5 g twice daily. A once-daily regimen of amikacin is never used and amikacin concentrations are not determined. In Belgium, Southport (U.K., Spain, and the VA McGuire Medical Center (Richmond, Virginia, amikacin is given once daily. Whereas peak and trough concentrations are determined in Belgium, only trough concentration is measured in Southport. In both these spinal units, modification of the dose is not routinely done with a nomogram. In Spain and the VA McGuire Medical Center, monitoring of serum amikacin concentration is not done unless a patient has renal impairment. In contrast, the dose/interval of amikacin is adjusted according to pharmacokinetic parameters at the Edward Hines VA Hospital (Hines, Illinois, where amikacin is administered q24h or q48h, depending on creatinine clearance. Spinal cord physicians from Denmark, Germany, and the Kessler Institute for Rehabilitation (West Orange, New Jersey state that they do not use amikacin in spinal injury patients. An expert from Canada does not recommend determining serum concentrations of amikacin, but emphasizes the value of monitoring ototoxicity and nephrotoxicity. Experts from New Zealand recommend amikacin in conventional twice- or thrice-daily dosing because of the theoretical increased risk of neuromuscular blockade and apnea with larger daily doses in spinal cord injury patients. On the contrary, experts from Greece, Israel, and the U.S. recommend once-daily dosing and determining amikacin pharmacokinetic parameters for each patient. As there is considerable variation in clinical

  17. Evaluation of the impact of banking umbilical cord blood units with high cell dose for ethnically diverse patients.

    Science.gov (United States)

    Stritesky, Gretta; Wadsworth, Kimberly; Duffy, Merry; Buck, Kelly; Dehn, Jason

    2018-02-01

    Umbilical cord blood units provide an important stem cell source for transplantation, particularly for patients of ethnic diversity who may not have suitably matched available, adult-unrelated donors. However, with the cost of cord blood unit acquisition from public banks significantly higher than that for adult-unrelated donors, attention is focused on decreasing cost yet still providing cord blood units to patients in need. Historical practices of banking units with low total nucleated cell counts, including units with approximately 90 × 10 7 total nucleated cells, indicates that most banked cord blood units have much lower total nucleated cell counts than are required for transplant. The objective of this study was to determine the impact on the ability to identify suitable cord blood units for transplantation if the minimum total nucleated cell count for banking were increased from 90 × 10 7 to 124 or 149 × 10 7 . We analyzed ethnically diverse patients (median age, 3 years) who underwent transplantation of a single cord blood unit in 2005 to 2016. A cord blood unit search was evaluated to identify units with equal or greater human leukocyte antigen matching and a greater total nucleated cell count than that of the transplanted cord blood unit (the replacement cord blood unit). If the minimum total nucleated cell count for banking increased to 124 or 149 × 10 7 , then from 75 to 80% of patients would still have at least 1 replacement cord blood unit in the current (2016) cord blood unit inventory. The best replacement cord blood units were often found among cords with the same ethnic background as the patient. The current data suggest that, if the minimum total nucleated cell count were increased for banking, then it would likely lead to an inventory of more desirable cord blood units while having minimal impact on the identification of suitable cord blood units for transplantation. © 2017 AABB.

  18. Comparison of adult and child radiation equivalent doses from 2 dental cone-beam computed tomography units.

    Science.gov (United States)

    Al Najjar, Anas; Colosi, Dan; Dauer, Lawrence T; Prins, Robert; Patchell, Gayle; Branets, Iryna; Goren, Arthur D; Faber, Richard D

    2013-06-01

    With the advent of cone-beam computed tomography (CBCT) scans, there has been a transition toward these scans' replacing traditional radiographs for orthodontic diagnosis and treatment planning. Children represent a significant proportion of orthodontic patients. Similar CBCT exposure settings are predicted to result in higher equivalent doses to the head and neck organs in children than in adults. The purpose of this study was to measure the difference in equivalent organ doses from different scanners under similar settings in children compared with adults. Two phantom heads were used, representing a 33-year-old woman and a 5-year-old boy. Optically stimulated dosimeters were placed at 8 key head and neck organs, and equivalent doses to these organs were calculated after scanning. The manufacturers' predefined exposure settings were used. One scanner had a pediatric preset option; the other did not. Scanning the child's phantom head with the adult settings resulted in significantly higher equivalent radiation doses to children compared with adults, ranging from a 117% average ratio of equivalent dose to 341%. Readings at the cervical spine level were decreased significantly, down to 30% of the adult equivalent dose. When the pediatric preset was used for the scans, there was a decrease in the ratio of equivalent dose to the child mandible and thyroid. CBCT scans with adult settings on both phantom heads resulted in higher radiation doses to the head and neck organs in the child compared with the adult. In practice, this might result in excessive radiation to children scanned with default adult settings. Collimation should be used when possible to reduce the radiation dose to the patient. While CBCT scans offer a valuable tool, use of CBCT scans should be justified on a specific case-by-case basis. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  19. Quality assurance in the measurement of internal radioactive contamination and dose assessment and the United States Department of Energy Laboratory Accreditation Program

    International Nuclear Information System (INIS)

    Bhatt, Anita

    2016-01-01

    The Quality Assurance for analytical measurement of internal radioactive contamination and dose assessment in the United States (US) is achieved through the US Department of Energy (DOE) Laboratory Accreditation Program (DOELAP) for both Dosimetry and Radio bioassay laboratories for approximately 150,000 radiation workers. This presentation will explain the link between Quality Assurance and the DOELAP Accreditation process. DOELAP is a DOE complex-wide safety program that ensures the quality of worker radiation protection programs. DOELAP tests the ability of laboratories to accurately measure and quantify radiation dose to workers and assures the laboratories quality systems are capable of defending and sustaining their measurement results. The United States Law in Title 10 of the Code of Federal Regulations 835 requires that personnel Dosimetry and Radio bioassay programs be tested and accredited

  20. Influence of geometrical parameters on the determination of the reference dose in Cobaltotherapy : case of the ALCYON II unit of the CHUA - HJRA

    International Nuclear Information System (INIS)

    RASOLONJATOVO, A.H.D.

    1998-01-01

    In application of the in force regulations in Madagascar, every practice inducing ionising radiation exposure must be conformed with the international basic safety standards. Particularly, practices in radiation therapy require high doses of radiation to be delivered with increased accuracy. It has been shown for the cobalt unit ALCYON II that a better accuracy than 5% needed is verified. This requires periodical quality controls, good calibration and high precision in handling of instruments. [fr

  1. Worker radiation doses in the United States at the dawn of the atomic era (1940--1960)

    International Nuclear Information System (INIS)

    Strom, D.J.; Smith, M.H.; Swinth, K.L.; Pettengill, H.J.

    1994-06-01

    Radiation doses to workers at the Manhattan Engineer District (MED) and US Atomic Energy Commission (AEC) sites due to external irradiation during 1940--1960 are reviewed. Categorized radiation dose data were available from AEC annual reports for some years. Annual individual radiation dose data for ten MED/AEC sites for all years were available from the US Department of Energy's (DOE) Comprehensive Epidemiologic Data Resource (CEDR). These data are combined to produce an estimate of external collective dose equivalent to 172,000 person-rems (1720 person-Sv) for 1940--1960. During this period there were 41 overexposures, 19 criticality incidents, and 3 deaths due to acute radiation syndrome among several hundred thousand workers

  2. The provision of national standards of absorbed dose for radiation processing. The role of NPL in the United Kingdom

    International Nuclear Information System (INIS)

    Ellis, S.C.

    1981-01-01

    The system of national and international standardization is examined, particularly with respect to the problems of standardizing high absorbed dose measurements required in processing with photons from cobalt-60 and electrons. The need for development of primary standards specifically dedicated to this application versus the possibility of extrapolation from standards in use at lower dose levels is considered together with means for dissemination and intercomparison. The present status of standards at NPL and the future programme are outlined. (author)

  3. X-rays, radiometers and skin unit dose. The development of measuring methods and measuring units for X radiation in medical physics from the beginning until the international standardization

    International Nuclear Information System (INIS)

    Glessmer-Junike, Simone

    2015-01-01

    X-rays, a special form of ionizing radiation, have been utilized in medicine and technology ever since their discovery at the end of 1895. However, the usage of X-rays made the development of measuring techniques necessary. Newly-developed measuring devices were at first called radiometers', but later the term dosimeter' has gained universal acceptance. The development of numerous dosimeters used in radiotherapy was accompanied by new units of measurement, each corresponding to its individual newly constructed dosimeter or method of measurement. While at first conversions between old and new units were performed, it later became clear that both within Germany and Europe units with similar names were used with different meanings, which was both incompatible and confusing. The first serious attempts of a standardization of units in Germany were made after the First World War, when the when the ionizing properties of X-rays was focused on for both measurements and unit definitions. Efforts towards an international standardization of units became successful in the mid-1920s when the Roentgen was defined as the universal unit. From the development described above, four stages of the evolution of radiation measurement and units in radiotherapy could be identified by means of comprehensive systematic research in printed publications. The first stage was the period of diagnostic application of X-rays, when tools for the determination of X-ray quality were designed. This stage progressed into that of therapeutic administration of X-rays shortly after, when instruments and units for the measurement of X-ray quantities (dose') were implemented. Due to the variety and diversity of measurement apparatus and units a third stage emerged, closely interconnected with the second. During the third stage, a nation-wide standardization was attempted in Germany. With the conclusion of this stage - the resolution of a unit for dose measurement in Germany - the stage of

  4. Disposition of cefixime in the material-fetal unit after an i.v. dose to pregnant rats

    International Nuclear Information System (INIS)

    Halperin-Walega, E.; Barr, A.; Tonelli, A.P.; Shin, K.; Batra, V.K.

    1986-01-01

    Cefixime, a potent, broad spectrum oral cephalosporin, is currently undergoing clinical trials. To determine the extent of transfer of cefixime across the placenta to the fetus, a single dose of 17.8 mg/kg 14 C-cefixime was administered to rats on day 18 of gestation via the caudal vein. Maternal serum and urine, fetal plasma and tissues, and placentae were sampled at appropriate times after dosing. Separate rats were subjected to whole body autoradiography. The half-life for elimination of radioactivity from both maternal serum and placentae was 6.9 hours. Elimination from fetal plasma and tissues was somewhat longer, 12.5 and 13.7 hours, respectively. However, based on a comparison of area under the curve, relative to maternal dose, exposure of the fetuses to cefixime was far less than that of placentae. Peak radioactivity in fetal plasma occurred at 2 hours and was less than 2% of the maternal peak at 0.5 hours after dosing. Whole body autoradiography showed the greatest radioactivity in maternal liver, kidney and intestines. Somewhat less radioactivity appeared in placentae and virtually none could be visualized within the amniotic sac. Overall, the data indicate that exposure of the rat fetus to cefixime after a single maternal dose is limited by the placenta

  5. Effect of Dietary Intake of Stable Iodine on Dose-per-unit-intake Factors for 99Tc

    Energy Technology Data Exchange (ETDEWEB)

    Strom, Daniel J.

    2003-09-30

    of stable iodine in the diet on the dose per unit intake factors for 99Tc without developing an improved biokinetic model for technetium. Specific experiments should be designed to quantitatively evaluate 99TcO4? metabolism, excretion, and secretion, as well as to evaluate its chemical toxicity It is recommended that the ICRP reexamine its biokinetics models for Tc based on nuclear medicine data that have accumulated over the years. In particular, the ICRP ignores the lactation pathway, the enhanced concentration of Tc in breast and breast milk, and enhanced concentration of Tc (and I) in the salivary glands as well as in the thyroid. The ICRP should also explicitly incorporate the effect of stable iodine in the diet into both its models for iodine and technetium. The effect of concentration of Tc in breast milk needs further study for dosimetric implications to nursing infants whose mothers may ingest 99TcO4? from groundwater sources. The ICRP should also investigate the possibility of enhanced concentration of both I and Tc in the non-lactating female breast. To do these re-evaluations of biokinetic models, new experiments designed specifically to evaluate these questions concerning the biokinetics of Tc and I are needed.

  6. Effect of Dietary Intake of Stable Iodine on Dose-per-unit-intake Factors for 99Tc

    International Nuclear Information System (INIS)

    Strom, Daniel J.

    2003-01-01

    of stable iodine in the diet on the dose per unit intake factors for 99Tc without developing an improved biokinetic model for technetium. Specific experiments should be designed to quantitatively evaluate 99TcO4? metabolism, excretion, and secretion, as well as to evaluate its chemical toxicity It is recommended that the ICRP reexamine its biokinetics models for Tc based on nuclear medicine data that have accumulated over the years. In particular, the ICRP ignores the lactation pathway, the enhanced concentration of Tc in breast and breast milk, and enhanced concentration of Tc (and I) in the salivary glands as well as in the thyroid. The ICRP should also explicitly incorporate the effect of stable iodine in the diet into both its models for iodine and technetium. The effect of concentration of Tc in breast milk needs further study for dosimetric implications to nursing infants whose mothers may ingest 99TcO4? from groundwater sources. The ICRP should also investigate the possibility of enhanced concentration of both I and Tc in the non-lactating female breast. To do these re-evaluations of biokinetic models, new experiments designed specifically to evaluate these questions concerning the biokinetics of Tc and I are needed

  7. A comparison of individual doses for continuous annual unit releases of tritium and activation products into brackish water and lake-river ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Edlund, O.; Aquilonius, K.

    1995-12-31

    The annual effective doses to critical group from potential unit releases of tritium and activation products (32 nuclides) from a hypothetical fusion reactor into two aquatic environments, one with brackish water and the other with fresh water, are assessed. Unit continuous releases (1 Bq/year during 50 years) for each relevant activation product are analyzed, and the effective dose rate is calculated for each nuclide. The transfer of released activity is simulated by compartment models using first-order linear differential equations for the transport. The rate constants for the brackish-water ecosystem are based on measurements. Four exposure pathways are considered in the brackish water system, the Tvaeren Bay, (a) consumption of fish, (b) consumption of milk, (c) consumption of meat, and (d) exposure from swimming. For the freshwater system, five additional pathways are considered, namely consumption of (e) water, (f) vegetables, (g) cereals, and (h) root vegetables and (i) external exposure from contaminated ground. The paper presents the compartment models used and a description of how the exposure pathways are treated, especially the pathways via food consumption. The dominating exposure pathways are for most of the nuclides consumption of fish and water. For Ag-isotopes other exposure pathways, such as ground-shine, cereals and meat, are of importance. The results of this study show that individual annual effective doses attributed to unit releases of most of the nuclides to the lake-river system become 1.3-60 times lower than those released to the brackish-water system. The niobium isotopes, however, give a factor 2.5-4.8 higher dose. The reason to that is that the values of the bioaccumulation factor for these isotopes are higher in fresh water than in marine water. An uncertainty analysis is performed on each ecosystem and the results are obtained in the form of distributions. 38 refs, 29 tabs.

  8. A comparison of individual doses for continuous annual unit releases of tritium and activation products into brackish water and lake-river ecosystems

    International Nuclear Information System (INIS)

    Edlund, O.; Aquilonius, K.

    1995-01-01

    The annual effective doses to critical group from potential unit releases of tritium and activation products (32 nuclides) from a hypothetical fusion reactor into two aquatic environments, one with brackish water and the other with fresh water, are assessed. Unit continuous releases (1 Bq/year during 50 years) for each relevant activation product are analyzed, and the effective dose rate is calculated for each nuclide. The transfer of released activity is simulated by compartment models using first-order linear differential equations for the transport. The rate constants for the brackish-water ecosystem are based on measurements. Four exposure pathways are considered in the brackish water system, the Tvaeren Bay, (a) consumption of fish, (b) consumption of milk, (c) consumption of meat, and (d) exposure from swimming. For the freshwater system, five additional pathways are considered, namely consumption of e) water, f) vegetables, g) cereals, and h) root vegetables and i) external exposure from contaminated ground. The paper presents the compartment models used and a description of how the exposure pathways are treated, especially the pathways via food consumption. The dominating exposure pathways are for most of the nuclides consumption of fish and water. For Ag-isotopes other exposure pathways, such as ground-shine, cereals and meat, are of importance. The results of this study show that individual annual effective doses attributed to unit releases of most of the nuclides to the lake-river system become 1.3-60 times lower than those released to the brackish-water system. The niobium isotopes, however, give a factor 2.5-4.8 higher dose. The reason to that is that the values of the bioaccumulation factor for these isotopes are higher in fresh water than in marine water. An uncertainty analysis is performed on each ecosystem and the results are obtained in the form of distributions. 38 refs, 29 tabs

  9. A comparison of individual doses for continuous annual unit releases of tritium and activation products into brackish water and lake-river ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Edlund, O; Aquilonius, K

    1996-12-31

    The annual effective doses to critical group from potential unit releases of tritium and activation products (32 nuclides) from a hypothetical fusion reactor into two aquatic environments, one with brackish water and the other with fresh water, are assessed. Unit continuous releases (1 Bq/year during 50 years) for each relevant activation product are analyzed, and the effective dose rate is calculated for each nuclide. The transfer of released activity is simulated by compartment models using first-order linear differential equations for the transport. The rate constants for the brackish-water ecosystem are based on measurements. Four exposure pathways are considered in the brackish water system, the Tvaeren Bay, (a) consumption of fish, (b) consumption of milk, (c) consumption of meat, and (d) exposure from swimming. For the freshwater system, five additional pathways are considered, namely consumption of (e) water, (f) vegetables, (g) cereals, and (h) root vegetables and (i) external exposure from contaminated ground. The paper presents the compartment models used and a description of how the exposure pathways are treated, especially the pathways via food consumption. The dominating exposure pathways are for most of the nuclides consumption of fish and water. For Ag-isotopes other exposure pathways, such as ground-shine, cereals and meat, are of importance. The results of this study show that individual annual effective doses attributed to unit releases of most of the nuclides to the lake-river system become 1.3-60 times lower than those released to the brackish-water system. The niobium isotopes, however, give a factor 2.5-4.8 higher dose. The reason to that is that the values of the bioaccumulation factor for these isotopes are higher in fresh water than in marine water. An uncertainty analysis is performed on each ecosystem and the results are obtained in the form of distributions. 38 refs, 29 tabs.

  10. Attempt to establish the ionizing radiation dose to be used in the sterilization of one-use medical equipment units

    International Nuclear Information System (INIS)

    Czerniawski, E.; Stolarczyk, L.

    1974-01-01

    The radioresistance of 8576 microbiological clones was examined. 8314 bacterial clones were isolated in the injection needle factory halls, from the surface exposed to strong ionizing irradiation sources. Those 649 clones which proved resistant to 2-4 Mrad radiation doses were used in further research work. The sterilizing value was based upon a detailed analysis of the bacteria according to their radioresistance groups and D 10 values. The 3 Mrad doses have to be used in order to achieve the sterility degree of a 10 6 product series with an initial 100-microorganisms infection. In case of a 1000/one product bacteria infection limit, the dose should be raised to 3.5 Mrad. (author)

  11. Design and optimize of 3-axis filament winding machine

    Science.gov (United States)

    Quanjin, Ma; Rejab, M. R. M.; Idris, M. S.; Bachtiar, B.; Siregar, J. P.; Harith, M. N.

    2017-10-01

    Filament winding technique is developed as the primary process for composite cylindrical structures fabrication at low cost. Fibres are wound on a rotating mandrel by a filament winding machine where resin impregnated fibres pass through a pay-out eye. This paper aims to develop and optimize a 3-axis, lightweight, practical, efficient, portable filament winding machine to satisfy the customer demand, which can fabricate pipes and round shape cylinders with resins. There are 3 main units on the 3-axis filament winding machine, which are the rotary unit, the delivery unit and control system unit. Comparison with previous existing filament winding machines in the factory, it has 3 degrees of freedom and can fabricate more complex shape specimens based on the mandrel shape and particular control system. The machine has been designed and fabricated on 3 axes movements with control system. The x-axis is for movement of the carriage, the y-axis is the rotation of mandrel and the z-axis is the movement of the pay-out eye. Cylindrical specimens with different dimensions and winding angles were produced. 3-axis automated filament winding machine has been successfully designed with simple control system.

  12. APPLICATION OF THE SPECTROMETRIC METHOD FOR CALCULATING THE DOSE RATE FOR CREATING CALIBRATION HIGHLY SENSITIVE INSTRUMENTS BASED ON SCINTILLATION DETECTION UNITS

    Directory of Open Access Journals (Sweden)

    R. V. Lukashevich

    2017-01-01

    Full Text Available Devices based on scintillation detector are highly sensitive to photon radiation and are widely used to measure the environment dose rate. Modernization of the measuring path to minimize the error in measuring the response of the detector to gamma radiation has already reached its technological ceiling and does not give the proper effect. More promising for this purpose are new methods of processing the obtained spectrometric information. The purpose of this work is the development of highly sensitive instruments based on scintillation detection units using a spectrometric method for calculating dose rate.In this paper we consider the spectrometric method of dosimetry of gamma radiation based on the transformation of the measured instrumental spectrum. Using predetermined or measured functions of the detector response to the action of gamma radiation of a given energy and flux density, a certain function of the energy G(E is determined. Using this function as the core of the integral transformation from the field to dose characteristic, it is possible to obtain the dose value directly from the current instrumentation spectrum. Applying the function G(E to the energy distribution of the fluence of photon radiation in the environment, the total dose rate can be determined without information on the distribution of radioisotopes in the environment.To determine G(E by Monte-Carlo method instrumental response function of the scintillator detector to monoenergetic photon radiation sources as well as other characteristics are calculated. Then the whole full-scale energy range is divided into energy ranges for which the function G(E is calculated using a linear interpolation.Spectrometric method for dose calculation using the function G(E, which allows the use of scintillation detection units for a wide range of dosimetry applications is considered in the article. As well as describes the method of calculating this function by using Monte-Carlo methods

  13. The Impact of High Versus Low Sedation Dosing Strategy on Cognitive Dysfunction in Survivors of Intensive Care Units: A Systematic Review and Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Porhomayon Jahan

    2015-06-01

    Full Text Available Background: The practice of low vs. high sedation dosing strategy may impact the cognitive and mental health function in the intensive care unit (ICU. We aim to demonstrate that high sedation strategy will result in change of mental health function in ICU patients. Methods: We performed a systemic search and meta-analysis of medical databases in MEDLINE(from 1966 to March 2013 and EMBASE (from 1980 to March 2013, as well as the Cochrane Library using the MESH terms "Intensive Care Unit," and "Mental Health, for assessing the impact of sedation on posttraumatic stress disorder (PTSD or anxiety/depression and deliriumin the mix ICU setting including cardiac surgery patients. A total of 1216 patients were includedin the final analysis.Results: We included 11 studies in the final analysis and concluded that high dose sedationstrategy resulted in higher incidence of cognitive dysfunction with P value of 0.009. Theresult for subgroup of delirium showed P = 0.11 and PTSD/depression or anxiety of P = 0.001,Heterogeneity I2 was 64%. Overall analysis was statistically significant with a P value of 0.002.Conclusion: High sedation dosing strategy will negatively affect cognitive function in criticallyill patients. Large randomized trials are needed to address cognitive dysfunction in subgroup of patients with delirium.

  14. Analysis of dose-incidence relationships for marrow failure in different species, in terms of radiosensitivity of tissue-rescuing units

    International Nuclear Information System (INIS)

    Hendry, J.H.; Roberts, S.A.

    1990-01-01

    The analysis of 68 published sets of dose-incidence data for marrow failure in different species, using a double-log mortality function, indicates: (a) There is more heterogeneity, i.e. greater sums-of-squares per degree of freedom, within the data sets for mouse than for larger species (monkey, dog, sheep, goat, pig). (b) For mice the curves for acute doses are characterized by a D0 of about 100 cGy for tissue-rescuing units (or target cells), which are depleted at most to about 3 x 10(-4) at LD50. (c) Larger species are much less tolerant to target-cell depletion, the corresponding level being consistently in the range of 10(-2)-10(-3) at LD50. Also, the D0 is often lower (approximately 55 cGy), which is compatible in the dog with such a value for hemopoietic progenitor cells. (d) With larger species there is an unexpected reduction in heterogeneity when the dose rate is lower, which gives a D0 lower than expected and a higher extrapolate. It is concluded that the position and slope of the dose-incidence curves are compatible with interpretations based primarily on target-cell number and survival characteristics, modified by additional heterogeneity factors

  15. Dose imprecision and resistance: free-choice medicated feeds in industrial food animal production in the United States.

    Science.gov (United States)

    Love, David C; Davis, Meghan F; Bassett, Anna; Gunther, Andrew; Nachman, Keeve E

    2011-03-01

    Industrial food animal production employs many of the same antibiotics or classes of antibiotics that are used in human medicine. These drugs can be administered to food animals in the form of free-choice medicated feeds (FCMF), where animals choose how much feed to consume. Routine administration of these drugs to livestock selects for microorganisms that are resistant to medications critical to the treatment of clinical infections in humans. In this commentary, we discuss the history of medicated feeds, the nature of FCMF use with regard to dose delivery, and U.S. policies that address antimicrobial drug use in food animals. FCMF makes delivering a predictable, accurate, and intended dose difficult. Overdosing can lead to animal toxicity; underdosing or inconsistent dosing can result in a failure to resolve animal diseases and in the development of antimicrobial-resistant microorganisms. The delivery of antibiotics to food animals for reasons other than the treatment of clinically diagnosed disease, especially via free-choice feeding methods, should be reconsidered.

  16. Analysis of Gamma Dose Rate Caused by Corrosion Products inside the Containment Building of Yonngwang Nuclear Power Plant Unit 3 During Shutdown Period

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Wi Ho; Kim, Jae Cheon; Kim, Soon Young; Kim, Jong Kyung [Hanyang Univ., Seoul (Korea, Republic of)

    2005-07-01

    Occupational radiation exposure(ORE) of nuclear power plant(NPP) workers mainly occurs during the shutdown period. Major radioactive sources are the corrosion products released from the reactor coolant system(RCS). The corrosion products consist of circulating crud and deposited crud. Major radioactive corrosion products, {sup 58}Co and {sup 60}Co, are known to contribute approximately more than 70% of the total ORE. In this study, the corrosion products regarding cobalt were evaluated during the shutdown period, and gamma dose rates caused by them were calculated at the main working area inside the containment building of the Yonggwang NPP Unit 3.

  17. A Comparison of Hazard Prediction and Assessment Capability (HPAC) Software Dose-Rate Contour Plots to a Sample of Local Fallout Data From Test Detonations in the Continental United States, 1945 - 1962

    National Research Council Canada - National Science Library

    Chancellor, Richard W

    2005-01-01

    A comparison of Hazard Prediction and Assessment Capability (HPAC) software dose-rate contour plots to a sample of local nuclear fallout data from test detonations in the continental United States, 1945 - 1962, is performed...

  18. Superficial dose evaluation of four dose calculation algorithms

    Science.gov (United States)

    Cao, Ying; Yang, Xiaoyu; Yang, Zhen; Qiu, Xiaoping; Lv, Zhiping; Lei, Mingjun; Liu, Gui; Zhang, Zijian; Hu, Yongmei

    2017-08-01

    Accurate superficial dose calculation is of major importance because of the skin toxicity in radiotherapy, especially within the initial 2 mm depth being considered more clinically relevant. The aim of this study is to evaluate superficial dose calculation accuracy of four commonly used algorithms in commercially available treatment planning systems (TPS) by Monte Carlo (MC) simulation and film measurements. The superficial dose in a simple geometrical phantom with size of 30 cm×30 cm×30 cm was calculated by PBC (Pencil Beam Convolution), AAA (Analytical Anisotropic Algorithm), AXB (Acuros XB) in Eclipse system and CCC (Collapsed Cone Convolution) in Raystation system under the conditions of source to surface distance (SSD) of 100 cm and field size (FS) of 10×10 cm2. EGSnrc (BEAMnrc/DOSXYZnrc) program was performed to simulate the central axis dose distribution of Varian Trilogy accelerator, combined with measurements of superficial dose distribution by an extrapolation method of multilayer radiochromic films, to estimate the dose calculation accuracy of four algorithms in the superficial region which was recommended in detail by the ICRU (International Commission on Radiation Units and Measurement) and the ICRP (International Commission on Radiological Protection). In superficial region, good agreement was achieved between MC simulation and film extrapolation method, with the mean differences less than 1%, 2% and 5% for 0°, 30° and 60°, respectively. The relative skin dose errors were 0.84%, 1.88% and 3.90%; the mean dose discrepancies (0°, 30° and 60°) between each of four algorithms and MC simulation were (2.41±1.55%, 3.11±2.40%, and 1.53±1.05%), (3.09±3.00%, 3.10±3.01%, and 3.77±3.59%), (3.16±1.50%, 8.70±2.84%, and 18.20±4.10%) and (14.45±4.66%, 10.74±4.54%, and 3.34±3.26%) for AXB, CCC, AAA and PBC respectively. Monte Carlo simulation verified the feasibility of the superficial dose measurements by multilayer Gafchromic films. And the rank

  19. SU-F-J-52: A Novel Approach to X-Ray Tube Quality Assurance for CBCT Systems in Order to Better Assess the Patient Imaging Dose in a Large, Multi-Unit Treatment Facility

    International Nuclear Information System (INIS)

    Buckley, L; Lambert, C; Nyiri, B; Gerig, L; Webb, R

    2016-01-01

    Purpose: To standardize the tube calibration for Elekta XVI cone beam CT (CBCT) systems in order to provide a meaningful estimate of the daily imaging dose and reduce the variation between units in a large centre with multiple treatment units. Methods: Initial measurements of the output from the CBCT systems were made using a Farmer chamber and standard CTDI phantom. The correlation between the measured CTDI and the tube current was confirmed using an Unfors Xi detector which was then used to perform a tube current calibration on each unit. Results: Initial measurements showed measured tube current variations of up to 25% between units for scans with the same image settings. In order to reasonably estimate the imaging dose, a systematic approach to x-ray generator calibration was adopted to ensure that the imaging dose was consistent across all units at the centre and was adopted as part of the routine quality assurance program. Subsequent measurements show that the variation in measured dose across nine units is on the order of 5%. Conclusion: Increasingly, patients receiving radiation therapy have extended life expectancies and therefore the cumulative dose from daily imaging should not be ignored. In theory, an estimate of imaging dose can be made from the imaging parameters. However, measurements have shown that there are large differences in the x-ray generator calibration as installed at the clinic. Current protocols recommend routine checks of dose to ensure constancy. The present study suggests that in addition to constancy checks on a single machine, a tube current calibration should be performed on every unit to ensure agreement across multiple machines. This is crucial at a large centre with multiple units in order to provide physicians with a meaningful estimate of the daily imaging dose.

  20. SU-F-J-52: A Novel Approach to X-Ray Tube Quality Assurance for CBCT Systems in Order to Better Assess the Patient Imaging Dose in a Large, Multi-Unit Treatment Facility

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, L; Lambert, C; Nyiri, B; Gerig, L [The Ottawa Hospital Cancer Ctr., Ottawa, ON (Canada); Webb, R [Elekta, Montreal, Quebec (Canada)

    2016-06-15

    Purpose: To standardize the tube calibration for Elekta XVI cone beam CT (CBCT) systems in order to provide a meaningful estimate of the daily imaging dose and reduce the variation between units in a large centre with multiple treatment units. Methods: Initial measurements of the output from the CBCT systems were made using a Farmer chamber and standard CTDI phantom. The correlation between the measured CTDI and the tube current was confirmed using an Unfors Xi detector which was then used to perform a tube current calibration on each unit. Results: Initial measurements showed measured tube current variations of up to 25% between units for scans with the same image settings. In order to reasonably estimate the imaging dose, a systematic approach to x-ray generator calibration was adopted to ensure that the imaging dose was consistent across all units at the centre and was adopted as part of the routine quality assurance program. Subsequent measurements show that the variation in measured dose across nine units is on the order of 5%. Conclusion: Increasingly, patients receiving radiation therapy have extended life expectancies and therefore the cumulative dose from daily imaging should not be ignored. In theory, an estimate of imaging dose can be made from the imaging parameters. However, measurements have shown that there are large differences in the x-ray generator calibration as installed at the clinic. Current protocols recommend routine checks of dose to ensure constancy. The present study suggests that in addition to constancy checks on a single machine, a tube current calibration should be performed on every unit to ensure agreement across multiple machines. This is crucial at a large centre with multiple units in order to provide physicians with a meaningful estimate of the daily imaging dose.

  1. Prevalence and Axis I Comorbidity of Full and Partial Posttraumatic Stress Disorder in the United States: Results from Wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions

    Science.gov (United States)

    Pietrzak, Robert H.; Goldstein, Risë B.; Southwick, Steven M.; Grant, Bridget F.

    2010-01-01

    The present study used data from the Wave 2 National Epidemiologic Survey on Alcohol and Related Conditions (n=34,653) to examine lifetime Axis I psychiatric comorbidity of posttraumatic stress disorder (PTSD) in a nationally representative sample of U.S. adults. Lifetime prevalences±standard errors of PTSD and partial PTSD were 6.4%±0.18 and 6.6%±0.18, respectively. Rates of PTSD and partial PTSD were higher among women (8.6%±0.26 and 8.6%±0.26) than men (4.1%±0.19 and 4.5%±0.21). Respondents with both PTSD and partial PTSD most commonly reported unexpected death of someone close, serious illness or injury to someone close, and sexual assault as their worst stressful experiences. PTSD and partial PTSD were associated with elevated lifetime rates of mood, anxiety, and substance use disorders, and suicide attempts. Respondents with partial PTSD generally had intermediate odds of comorbid Axis I disorders and psychosocial impairment relative to trauma controls and full PTSD. PMID:21168991

  2. Passive dosing of polycyclic aromatic hydrocarbon (PAH) mixtures to terrestrial springtails: linking mixture toxicity to chemical activities, equilibrium lipid concentrations, and toxic units.

    Science.gov (United States)

    Schmidt, Stine N; Holmstrup, Martin; Smith, Kilian E C; Mayer, Philipp

    2013-07-02

    A 7-day mixture toxicity experiment with the terrestrial springtail Folsomia candida was conducted, and the effects were linked to three different mixture exposure parameters. Passive dosing from silicone was applied to tightly control exposure levels and compositions of 12 mixture treatments, containing the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene, and pyrene. Springtail lethality was then linked to sum chemical activities (∑a), sum equilibrium lipid concentrations (∑C(lipid eq.)), and sum toxic units (∑TU). In each case, the effects of all 12 mixture treatments could be fitted to one sigmoidal exposure-response relationship. The effective lethal chemical activity (La50) of 0.027 was well within the expected range for baseline toxicity of 0.01-0.1. Linking the effects to the lipid-based exposure parameter yielded an effective lethal concentration (LC(lipid eq 50)) of 133 mmol kg(-1) lipid in good correspondence with the lethal membrane burden for baseline toxicity (40-160 mmol kg(-1) lipid). Finally, the effective lethal toxic unit (LTU50) of 1.20 was rather close to the expected value of 1. Altogether, passive dosing provided tightly controlled mixture exposure in terms of both level and composition, while ∑a, ∑C(lipid eq.), and ∑TU allowed baseline toxicity to be linked to mixture exposure.

  3. A Cost-Benefit Analysis of Low-Dose Aspirin Prophylaxis for the Prevention of Preeclampsia in the United States.

    Science.gov (United States)

    Werner, Erika F; Hauspurg, Alisse K; Rouse, Dwight J

    2015-12-01

    To develop a decision model to evaluate the risks, benefits, and costs of different approaches to aspirin prophylaxis for the approximately 4 million pregnant women in the United States annually. We created a decision model to evaluate four approaches to aspirin prophylaxis in the United States: no prophylaxis, prophylaxis per American College of Obstetricians and Gynecologists (the College) recommendations, prophylaxis per U.S. Preventive Services Task Force recommendations, and universal prophylaxis. We included the costs associated with aspirin, preeclampsia, preterm birth, and potential aspirin-associated adverse effects. TreeAge Pro 2011 was used to perform the analysis. The estimated rate of preeclampsia would be 4.18% without prophylaxis compared with 4.17% with the College approach in which 0.35% (n=14,000) of women receive aspirin, 3.83% with the U.S. Preventive Services Task Force approach in which 23.5% (n=940,800) receive aspirin, and 3.81% with universal prophylaxis. Compared with no prophylaxis, the U.S. Preventive Services Task Force approach would save $377.4 million in direct medical care costs annually, and universal prophylaxis would save $365 million assuming 4 million births each year. The U.S. Preventive Services Task Force approach is the most cost-beneficial in 79% of probabilistic simulations. Assuming a willingness to pay of $100,000 per neonatal quality-adjusted life-year gained, the universal approach is the most cost-effective in more than 99% of simulations. Both the U.S. Preventive Services Task Force approach and universal prophylaxis would reduce morbidity, save lives, and lower health care costs in the United States to a much greater degree than the approach currently recommended by the College.

  4. Gut Microbiota-brain Axis

    Institute of Scientific and Technical Information of China (English)

    Hong-Xing Wang; Yu-Ping Wang

    2016-01-01

    Objective:To systematically review the updated information about the gut microbiota-brain axis.Data Sources:All articles about gut microbiota-brain axis published up to July 18,2016,were identified through a literature search on PubMed,ScienceDirect,and Web of Science,with the keywords of"gut microbiota","gut-brain axis",and "neuroscience".Study Selection:All relevant articles on gut microbiota and gut-brain axis were included and carefully reviewed,with no limitation of study design.Results:It is well-recognized that gut microbiota affects the brain's physiological,behavioral,and cognitive functions although its precise mechanism has not yet been fully understood.Gut microbiota-brain axis may include gut microbiota and their metabolic products,enteric nervous system,sympathetic and parasympathetic branches within the autonomic nervous system,neural-immune system,neuroendocrine system,and central nervous system.Moreover,there may be five communication routes between gut microbiota and brain,including the gut-brain's neural network,neuroendocrine-hypothalamic-pituitary-adrenal axis,gut immune system,some neurotransmitters and neural regulators synthesized by gut bacteria,and barrier paths including intestinal mucosal barrier and blood-brain barrier.The microbiome is used to define the composition and functional characteristics of gut microbiota,and metagenomics is an appropriate technique to characterize gut microbiota.Conclusions:Gut microbiota-brain axis refers to a bidirectional information network between the gut microbiota and the brain,which may provide a new way to protect the brain in the near future.

  5. Proper time axis of a closed relativistic system

    International Nuclear Information System (INIS)

    Chernikov, N.A.; Fadeev, N.G.; Shavokhina, N.S.

    1997-01-01

    The definition of a proper time axis of a closed relativistic system of colliding particles is given. The solution of the proper time axis problem is presented. If the light velocity c equals the imaginary unit i, then in the case of a plane motion of the system the problem about the proper time axis turns out to be equivalent to the known in engineering mechanics problem about the reduction of any system of forces, applied to a rigid body, to the dynamic screw. In the general case, when c=i, the problem about the proper time axis turns out to be equivalent to the problem about the reduction to the dynamic screw of a system of forces, applied to a rigid body in a four-dimensional Euclidean space

  6. Cost-effectiveness of a 12-dose regimen for treating latent tuberculous infection in the United States

    Science.gov (United States)

    Shepardson, D.; Marks, S. M.; Chesson, H.; Kerrigan, A.; Holland, D. P.; Scott, N.; Tian, X.; Borisov, A. S.; Shang, N.; Heilig, C. M.; Sterling, T. R.; Villarino, M. E.; Mac Kenzie, W. R.

    2017-01-01

    SUMMARY SETTING A large randomized controlled trial recently showed that for treating latent tuberculous infection (LTBI) in persons at high risk of progression to tuberculosis (TB) disease, a 12-dose regimen of weekly rifapentine plus isoniazid (3HP) administered as directly observed treatment (DOT) can be as effective as 9 months of daily self-administered isoniazid (9H). OBJECTIVES To assess the cost-effectiveness of 3HP compared to 9H. DESIGN A computational model was designed to simulate individuals with LTBI treated with 9H or 3HP. Costs and health outcomes were estimated to determine the incremental costs per active TB case prevented and per quality-adjusted life year (QALY) gained by 3HP compared to 9H. RESULTS Over a 20-year period, treatment of LTBI with 3HP rather than 9H resulted in 5.2 fewer cases of TB and 25 fewer lost QALYs per 1000 individuals treated. From the health system and societal perspectives, 3HP would cost respectively US$21 525 and $4294 more per TB case prevented, and respectively $4565 and $911 more per QALY gained. CONCLUSIONS 3HP may be a cost-effective alternative to 9H, particularly if the cost of rifapentine decreases, the effectiveness of 3HP can be maintained without DOT, and 3HP treatment is limited to those with a high risk of progression to TB disease. PMID:24200264

  7. Vertical axis wind turbine airfoil

    Science.gov (United States)

    Krivcov, Vladimir; Krivospitski, Vladimir; Maksimov, Vasili; Halstead, Richard; Grahov, Jurij Vasiljevich

    2012-12-18

    A vertical axis wind turbine airfoil is described. The wind turbine airfoil can include a leading edge, a trailing edge, an upper curved surface, a lower curved surface, and a centerline running between the upper surface and the lower surface and from the leading edge to the trailing edge. The airfoil can be configured so that the distance between the centerline and the upper surface is the same as the distance between the centerline and the lower surface at all points along the length of the airfoil. A plurality of such airfoils can be included in a vertical axis wind turbine. These airfoils can be vertically disposed and can rotate about a vertical axis.

  8. Helical axis stellarator equilibrium model

    International Nuclear Information System (INIS)

    Koniges, A.E.; Johnson, J.L.

    1985-02-01

    An asymptotic model is developed to study MHD equilibria in toroidal systems with a helical magnetic axis. Using a characteristic coordinate system based on the vacuum field lines, the equilibrium problem is reduced to a two-dimensional generalized partial differential equation of the Grad-Shafranov type. A stellarator-expansion free-boundary equilibrium code is modified to solve the helical-axis equations. The expansion model is used to predict the equilibrium properties of Asperators NP-3 and NP-4. Numerically determined flux surfaces, magnetic well, transform, and shear are presented. The equilibria show a toroidal Shafranov shift

  9. DARHT Axis-I Diode Simulations II: Geometrical Scaling

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Carl A. Jr. [Los Alamos National Laboratory

    2012-06-14

    Flash radiography of large hydrodynamic experiments driven by high explosives is a venerable diagnostic technique in use at many laboratories. Many of the largest hydrodynamic experiments study mockups of nuclear weapons, and are often called hydrotests for short. The dual-axis radiography for hydrodynamic testing (DARHT) facility uses two electron linear-induction accelerators (LIA) to produce the radiographic source spots for perpendicular views of a hydrotest. The first of these LIAs produces a single pulse, with a fixed {approx}60-ns pulsewidth. The second axis LIA produces as many as four pulses within 1.6-{micro}s, with variable pulsewidths and separation. There are a wide variety of hydrotest geometries, each with a unique radiographic requirement, so there is a need to adjust the radiographic dose for the best images. This can be accomplished on the second axis by simply adjusting the pulsewidths, but is more problematic on the first axis. Changing the beam energy or introducing radiation attenuation also changes the spectrum, which is undesirable. Moreover, using radiation attenuation introduces significant blur, increasing the effective spot size. The dose can also be adjusted by changing the beam kinetic energy. This is a very sensitive method, because the dose scales as the {approx}2.8 power of the energy, but it would require retuning the accelerator. This leaves manipulating the beam current as the best means for adjusting the dose, and one way to do this is to change the size of the cathode. This method has been proposed, and is being tested. This article describes simulations undertaken to develop scaling laws for use as design tools in changing the Axis-1 beam current by changing the cathode size.

  10. Dose conversion factors

    International Nuclear Information System (INIS)

    Kocher, D.C.; Eckerman, K.F.

    1992-01-01

    The following is discussed in this report: concepts and quantities used in calculating radiation dose from internal and external exposure. Tabulations of dose conversion factor for internal and external exposure to radionuclides. Dose conversion factors give dose per unit intake (internal) or dose per unit concentration in environment (external). Intakes of radionuclides for internal exposure and concentrations of radionuclides in environment for external exposure are assumed to be known. Intakes and concentrations are obtained, e.g., from analyses of environmental transport and exposure pathways. differences between dosimetry methods for radionuclides and hazardous chemicals are highlighted

  11. Absorbed dose in CT. Comparison by CT dose index

    International Nuclear Information System (INIS)

    Yamamoto, Kenji; Akazawa, Hiroshi; Andou, Takashi

    2002-01-01

    Few reports have discussed the absorbed dose on CT units with increased scanning capacity even with the current widespread adoption of multi-slice CT units. To compare and investigate the dose indexes among CT units, we measured the absorbed dose on CT units operating in Nagano Prefecture Japan. The measurements showed proportionality between phantom absorbed dose and the exposured mAs values in conventional scanning operation. Further, the measurements showed that the absorbed dose in the center of the phantom differed by about 2.1-fold between the highest and lowest levels on individual CT units. Within a single company, multi-slice CT units of the same company gave absorbed doses of about 1.3 to 1.5 times those of conventional single-slice CT units under the same exposured conditions of conventional scanning. When the scanning pitch was reduced in helical scanning, the absorbed dose at the center of the phantom increased. (author)

  12. Evaluation of eleven years of area monitoring for external dose rate in a deposit of radioactive waste at the ore treatment unit

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, W.S.; Oliveira, S.Q. de; Py Junior, D.A.; Silva, A.C.A.; Garcia Filho, O., E-mail: pereiraws@gmail.com [Industrias Nucleares do Brasil (INB), Pocos de Caldas, MG (Brazil). Unidade de Tratamento de Minerio. Grupo Multidisciplinar de Radioprotecao; Kelecom, A., E-mail: akelecom@id.uff.br [Universidade Federal Fluminense (LARARA-PLS/GETA/UFF), Niteroi, RJ, (Brazil). Lab. de Radiobiologia e Radiometria. Grupo de Estudos em Temas Ambientais; Pereira, J.R.S., E-mail: pereirarsj@gmail.com [Universidade Federal de Alfenas (UNIFAL), Pocos de Caldas, MG (Brazil)

    2013-07-01

    At Ore Treatment Unit (UTM, in Portuguese) situated in Pocos de Caldas, MG, there is a deposit of about 40 tons radioactive waste produced decades ago from Santo Amaro deactivated plant (SAP) and then from NUCLEMON that processed monazite sands to extract rare earth elements. This waste contains uranium and thorium and it is stored in six hangars. This study aims to analyze the dose rates in the hangars from 2002 to 2012. Annually, two samples were obtained, for a total of 24 samples. The results showed the highest doses rates at UTM, ranging from 0.5 to 409.8 μSv h{sup -}'1 for the total set of samples. The averages extended from 0.96 μSv h{sup -1} in hangar C-02 up to 282.64 μSv h{sup -1} in hangar C-05. Considering each hangar separately, the results were as follows: hangar C-01 average 30.34 μSv h{sup -1}, ranging from 6.2 to 71.7 μSv h{sup -1}; hangar C-02 average 0.96 μSv h{sup -1} (min-max 0.5 to 2.51 μSv h{sup -1}); hangar C-05 average 282.64 μSv h{sup -1} (min-max 3.7 to 409.8 μSv h{sup -1}); hangar C-06 average 188.92 μSv h{sup -1} (min-max 1.85 to 338.0 μSv h{sup -1}); hangar C-07, average 172.05 μSv h{sup -1} (min-max 1.95 to 283.0 μSv h{sup -1}) and hangar C-09, average 122.59 μSv h{sup -1} (min-max 1.11 to 277.0 μSv h{sup -1}). ANOVA test indicated that the dose rates averages in the six hangars are different (F{sub calc} of 70.90 higher F{sub crit} of 2.28), and the Tukey test allowed to group the hangars in the following sequence: C-05> C-06 = C-07> C-09> C-01 = C-02. (author)

  13. Evaluation of eleven years of area monitoring for external dose rate in a deposit of radioactive waste at the ore treatment unit

    International Nuclear Information System (INIS)

    Pereira, W.S.; Oliveira, S.Q. de; Py Junior, D.A.; Silva, A.C.A.; Garcia Filho, O.

    2013-01-01

    At Ore Treatment Unit (UTM, in Portuguese) situated in Pocos de Caldas, MG, there is a deposit of about 40 tons radioactive waste produced decades ago from Santo Amaro deactivated plant (SAP) and then from NUCLEMON that processed monazite sands to extract rare earth elements. This waste contains uranium and thorium and it is stored in six hangars. This study aims to analyze the dose rates in the hangars from 2002 to 2012. Annually, two samples were obtained, for a total of 24 samples. The results showed the highest doses rates at UTM, ranging from 0.5 to 409.8 μSv h - '1 for the total set of samples. The averages extended from 0.96 μSv h -1 in hangar C-02 up to 282.64 μSv h -1 in hangar C-05. Considering each hangar separately, the results were as follows: hangar C-01 average 30.34 μSv h -1 , ranging from 6.2 to 71.7 μSv h -1 ; hangar C-02 average 0.96 μSv h -1 (min-max 0.5 to 2.51 μSv h -1 ); hangar C-05 average 282.64 μSv h -1 (min-max 3.7 to 409.8 μSv h -1 ); hangar C-06 average 188.92 μSv h -1 (min-max 1.85 to 338.0 μSv h -1 ); hangar C-07, average 172.05 μSv h -1 (min-max 1.95 to 283.0 μSv h -1 ) and hangar C-09, average 122.59 μSv h -1 (min-max 1.11 to 277.0 μSv h -1 ). ANOVA test indicated that the dose rates averages in the six hangars are different (F calc of 70.90 higher F crit of 2.28), and the Tukey test allowed to group the hangars in the following sequence: C-05> C-06 = C-07> C-09> C-01 = C-02. (author)

  14. Endorectal high dose rate brachytherapy quality assurance

    International Nuclear Information System (INIS)

    Devic, S.; Vuong, T.; Evans, M.; Podgorsak, E.

    2008-01-01

    We describe our quality assurance method for preoperative high dose rate (HDR) brachytherapy of endorectal tumours. Reproduction of the treatment planning dose distribution on a daily basis is crucial for treatment success. Due to the cylindrical symmetry, two types of adjustments are necessary: applicator rotation and dose distribution shift along the applicator axis. (author)

  15. Efficiency of the DOMUS 750 vertical-axis wind turbine

    Science.gov (United States)

    Hallock, Kyle; Rasch, Tyler; Ju, Guoqiang; Alonso-Marroquin, Fernando

    2017-06-01

    The aim of this paper is to present some preliminary results on the efficiency of a wind turbine for an off-grid housing unit. To generate power, the unit uses a photovoltaic solar array and a vertical-axis wind turbine (VAWT). The existing VAWT was analysed to improve efficiency and increase power generation. There were found to be two main sources of inefficiency: 1. the 750W DC epicyclic generator performed poorly in low winds, and 2. the turbine blades wobbled, allowing for energy loss due to off-axis rotation. A 12V DC permanent magnet alternator was chosen that met the power requirements of the housing unit and would generate power at lower wind speeds. A support bracket was designed to prevent the turbine blades from wobbling.

  16. The Dose-Response Relationship Between Tobacco Education Advertising and Calls to Quitlines in the United States, March-June, 2012.

    Science.gov (United States)

    Davis, Kevin C; Alexander, Robert L; Shafer, Paul; Mann, Nathan; Malarcher, Ann; Zhang, Lei

    2015-11-05

    We estimated changes in call volume in the United States in response to increases in advertising doses of the Tips From Former Smokers (Tips) campaign, the first federal national tobacco education campaign, which aired for 12 weeks from March 19 to June 10, 2012. We also measured the effectiveness of ad taglines that promoted calls directly with a quitline number (1-800-QUIT-NOW) and indirectly with a cessation help website (Smokefree.gov). Multivariate regressions estimated the weekly number of calls to 1-800-QUIT-NOW by area code as a function of weekly market-level gross rating points (GRPs) from CDC's Tips campaign in 2012. The number of quitline calls attributable solely to Tips was predicted. For quitline-tagged ads, an additional 100 television GRPs per week was associated with an increase of 89 calls per week in a typical area code in the United States (P advertising GRPs for ads tagged with Smokefree.gov was associated with an increase of 29 calls per week in any given area code (P < .001). We estimated that the Tips campaign was responsible for more than 170,000 additional calls to 1-800-QUIT-NOW during the campaign and that it would have generated approximately 140,000 additional calls if all ads were tagged with 1-800-QUIT-NOW. For campaign planners, these results make it possible to estimate 1) the likely impact of tobacco prevention media buys and 2) the additional quitline capacity needed at the national level should future campaigns of similar scale use 1-800-QUIT-NOW taglines exclusively.

  17. Simple experimentally derived algorithm for computer calculated dose rates associated with /sup 137/Cs gynecologic insertions

    Energy Technology Data Exchange (ETDEWEB)

    Wrede, D E; Dawalibi, H [King Faisal Specialist Hospital and Research Centre, Department of Medical Physics. Riyadh (Saudi Arabia)

    1980-01-01

    A simple mathematical algorithm is derived from experimental data for dose rates from /sup 137/Cs sources in a finite tissue equivalent medium corresponding to the female pelvis. An analytical expression for a point source of /sup 137/Cs along with a simple numerical integration routine allows for rapid as well as accurate dose rate calculations at points of interest for gynecologic insertions. When compared with theoretical models assuming an infinite unit density medium, the measured dose rates are found to be systematically lower at distances away from a single source; 5 per cent at 2 cm and 10 per cent at 7 cm along the transverse axis. Allowance in the program for print out of dose rates from individual sources to a given point and the feature of source strength modification allows for optimization in terms of increasing the difference in dose rate between reference treatment points and sensitive structures such as the bladder, rectum and colon.

  18. Simple experimentally derived algorithm for computer calculated dose rates associated with 137Cs gynecologic insertions

    International Nuclear Information System (INIS)

    Wrede, D.E.; Dawalibi, H.

    1980-01-01

    A simple mathematical algorithm is derived from experimental data for dose rates from 137 Cs sources in a finite tissue equivalent medium corresponding to the female pelvis. An analytical expression for a point source of 137 Cs along with a simple numerical integration routine allows for rapid as well as accurate dose rate calculations at points of interest for gynecologic insertions. When compared with theoretical models assuming an infinite unit density medium, the measured dose rates are found to be systematically lower at distances away from a single source; 5 per cent at 2 cm and 10 per cent at 7 cm along the transverse axis. Allowance in the program for print out of dose rates from individual sources to a given point and the feature of source strength modification allows for optimization in terms of increasing the difference in dose rate between reference treatment points and sensitive structures such as the bladder, rectum and colon. (Auth.)

  19. EURISOL-DS multi-MW target unit: Neutronics performance and shielding assessment, dose rate and material activation calculations for the MAFF configuration

    CERN Document Server

    Romanets, Y; Kadi, Y; Luis, R; Goncalves, I F; Tecchio, L; Kharoua, C; Vaz, P; Ene, D; David, J C; Rocca, R; Negoita, F

    2010-01-01

    One of the objectives of the EURISOL (EURopean Isotope Separation On-Line Radioactive Ion Beam) Design Study consisted of providing a safe and reliable facility layout and design for the following operational parameters and characteristics: (a) a 4 MW proton beam of 1 GeV energy impinging on a mercury target (the converter); (b) high neutron fluxes (similar to 3 x 10(16) neutrons/s) generated by spallation reactions of the protons impinging in the converter and (c) fission rate on fissile U-235 targets in excess of 10(15) fissions/s. In this work, the state-of-the-art Monte Carlo codes MCNPX (Pelowitz, 2005) and FLUKA (Vlachoudis, 2009; Ferrari et al., 2008) were used to characterize the neutronics performance and to perform the shielding assessment (Herrera-Martinez and Kadi, 2006; Cornell, 2003) of the EURISOLTarget Unit and to provide estimations of dose rate and activation of different components, in view of the radiation safety assessment of the facility. Dosimetry and activation calculations were perfor...

  20. Craniospinal axis irradiation: an improved electron technique for irradiation of the spinal axis

    International Nuclear Information System (INIS)

    Chun Li; Vijayakumar, S.; Myrianthopoulos, L.C.; Kuchnir, F.T.; Muller-Runkel, R.

    1994-01-01

    The authors review dosimetric features of craniospinal axis irradiation in the areas of matching cranial and spinal fields, with reference to normal structures within the spinal field. The implications of the use of photon or electron modalities for the spinal port were evaluated. A novel method of matching the cranial photon and the spinal electron fields involving a computer-aided junction design is presented, involving moving the photon beam in three steps to degrade its penumbra to match that of the electron field. Thermoluminescent dosimetry in a Rando phantom and computed tomography-based dose-volume histogram study for an illustrative paediatric case were used to compare dose to normal structures within the spinal field. Results show that the use of electrons for the spinal field leads to better sparing of deep seated normal structures. For bone marrow, the use of a customized bolus for the spinal field results in an improved dose distribution, making electrons potentially superior to photons for radiobiological reasons. (author)

  1. Water vapor δ17O measurements using an off-axis integrated cavity output spectrometer and seasonal variation in 17O-excess of precipitation in the east-central United States

    Science.gov (United States)

    Tian, C.; Wang, L.; Novick, K. A.

    2016-12-01

    High-precision triple oxygen isotope analysis can be used to improve our understanding of multiple hydrological and meteorological processes. Recent studies focus on understanding 17O-excess variation of tropical storms, high-latitude snow and ice-core as well as spatial distribution of meteoric water (tap water). The temporal scale of 17O-excess variation in middle-latitude precipitation is needed to better understand which processes control on the 17O-excess variations. This study focused on assessing how the accuracy and precision of vapor δ17O laser spectroscopy measurements depend on vapor concentration, delta range, and averaging-time. Meanwhile, we presented 17O-excess data from two-year, event based precipitation sampling in the east-central United States. A Triple Water Vapor Isotope Analyzer (T-WVIA) was used to evaluate the accuracy and precision of δ2H, δ18O and δ17O measurements. GISP and SLAP2 from IAEA and four working standards were used to evaluate the sensitivity in the three factors. Overall, the accuracy and precision of all isotope measurements were sensitive to concentration, with higher accuracy and precision generally observed under moderate vapor concentrations (i.e., 10000-15000 ppm) for all isotopes. Precision was also sensitive to the range of delta values, though the effect was not as large when compared to the sensitivity to concentration. The precision was much less sensitive to averaging time when compared with concentration and delta range effects. The preliminary results showed that 17O-excess variation was lower in summer (23±17 per meg) than in winter (34±16 per meg), whereas spring values (30±21 per meg) was similar to fall (29±13 per meg). That means kinetic fractionation influences the isotopic composition and 17O-excess in different seasons.

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-07-08

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

  4. Studies of absorbed dose determinations and spatial dose distributions for high energy proton beams

    International Nuclear Information System (INIS)

    Hiraoka, Takeshi

    1982-01-01

    Absolute dose determinations were made with three types of ionization chamber and a Faraday cup. Methane based tissue equivalent (TE) gas, nitrogen, carbon dioxide, air were used as an ionizing gas with flow rate of 10 ml per minute. Measurements were made at the entrance position of unmodulated beams and for a beam of a spread out Bragg peak at a depth of 17.3 mm in water. For both positions, the mean value of dose determined by the ionization chambers was 0.993 +- 0.014 cGy for which the value of TE gas was taken as unity. The agreement between the doses estimated by the ionization chambers and the Faraday cup was within 5%. Total uncertainty estimated in the ionization chamber and the Faraday cup determinations is 6 and 4%, respectively. Common sources of error in calculating the dose from ionization chamber measurements are depend on the factors of ion recombination, W value, and mass stopping power ratio. These factors were studied by both experimentally and theoretically. The observed values for the factors show a good agreement to the predicted one. Proton beam dosimetry intercomparison between Japan and the United States was held. Good agreement was obtained with standard deviation of 1.6%. The value of the TE calorimeter is close to the mean value of all. In the proton spot scanning system, lateral dose distributions at any depth for one spot beam can be simulated by the Gaussian distribution. From the Gaussian distributions and the central axis depth doses for one spot beam, it is easy to calculate isodose distributions in the desired field by superposition of dose distribution for one spot beam. Calculated and observed isodose curves were agreed within 1 mm at any dose levels. (J.P.N.)

  5. A study to determine the differences between the displayed dose values for two full-field digital mammography units and values calculated using a range of Monte-Carlo-based techniques: A phantom study

    International Nuclear Information System (INIS)

    Borg, M.; Badr, I.; Royle, G. J.

    2013-01-01

    Modern full-field digital mammography (FFDM) units display the mean glandular dose (MGD) and the entrance or incident air kerma (K) to the breast following each exposure. Information on how these values are calculated is limited and knowing how displayed MGD values compare and correlate to conventional Monte-Carlo-based methods is useful. From measurements done on polymethyl methacrylate (PMMA) phantoms, it has been shown that displayed and calculated MGD values are similar for thin to medium thicknesses and appear to differ with larger PMMA thicknesses. As a result, a multiple linear regression analysis on the data was performed to generate models by which displayed MGD values on the two FFDM units included in the study may be converted to the Monte-Carlo values calculated by conventional methods. These models should be a useful tool for medical physicists requiring MGD data from FFDM units included in this paper and should reduce the survey time spent on dose calculations. (authors)

  6. Dose in sensitive organs during the prostate treatment with a {sup 60}Co unit; Dosis en organos sensibles durante el tratamiento de prostata con una unidad de {sup 60}Co

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Apdo. Postal 336, 98000 Zacatecas (Mexico); Navarro B, J. A. [Universidad Autonoma de Zacatecas, Unidad Academica de Fisica, Carretera a la Bufa s/n, Zacatecas (Mexico); Perez A, M. L.; Perez L, L. H., E-mail: fermineutron@yahoo.com [Instituto Zacatecano del Tumor, A. C., Lago de la Encantada No. 294, Fracc. Lomas del Lago, Zacatecas (Mexico)

    2012-10-15

    The absorbed dose by the bladder, the rectum and the gland thyroid was measured during a treatment applied for prostate cancer by means of a Cobalt 60 unit. The dose was measured using thermoluminescent dosimeters of the type TLD 100, with the values of the absorbed the values of the effective dose were calculated and was determined the probability of the development of a secondary cancer. Because these measurements cannot be made -in vivo- a phantom or mannequin was built with water that represents the hip and part of the torso of the human body and to represent the neck was used polyethylene. The study was carried out in the Instituto Zacatecano del Tumor that has a -cobalt bomb- which is used to treat oncology patients, during the phantom irradiation a dose of 200 c Gy was applied of this dose the bladder received 96.7%, the rectum 100.8% and the gland thyroid 0.3%. The dose received by the rectum and the bladder is due to the therapeutic beam while the dose received by the thyroid is due to the dispersed radiation by the phantom. The probability that in these organs a new neoplasm is developed is of 0.033% for the bladder, 0.157% for the rectum and 7.8 x 10{sup -5}% for the thyroid case. (Author)

  7. Capability of the nematode-trapping fungus Duddingtonia flagrans to reduce infective larvae of gastrointestinal nematodes in goat feces in the southeastern United States: dose titration and dose time interval studies.

    Science.gov (United States)

    Terrill, T H; Larsen, M; Samples, O; Husted, S; Miller, J E; Kaplan, R M; Gelaye, S

    2004-04-15

    Infection with gastrointestinal nematodes, particularly Haemonchus contortus, is a major constraint to goat production in the southeastern United States. Non-anthelmintic control alternatives are needed due to increasing resistance of these nematodes to available anthelmintics. Two studies were completed in Central Georgia in August 1999, and April-May 2000, using Spanish does naturally infected with Haemonchus contortus, Trichostongylus colubriformis, and Cooperia spp. to evaluate effectiveness of nematode-trapping fungi as a biological control agent. In the first experiment, five levels of Duddingtonia flagrans spores were mixed with a complete diet and fed once daily to the does (three per treatment) in metabolism crates. The treatment concentrations were (1) 5 x 10(5), (2) 2.5 x 10(5), (3) 10(5), and (4) 5 x 10(4) spores per kilogram body weight (BW), and (5) no spores. Fungal spores were fed for the first 7 days of the 14-day trial, and fecal samples were collected daily from individual animals for analysis of fecal egg count and establishment of fecal cultures. Efficacy of the fungus at reducing development of infective larvae (L3) in the fecal cultures was evaluated. The mean reduction in L3 from day 2 of the treatment period until the day after treatment stopped (days 2-8) was 93.6, 80.2, 84.1, and 60.8% for animals given the highest to lowest spore doses, respectively. Within 3-6 days after termination of fungal spore feedings, reduction in L3 development was no longer apparent in any of the treated animals. In a second experiment, effectiveness of 2.5 x 10(5) spores of D. flagrans per kilogram BW fed to does every day, every second day, and every third day was evaluated. Reduction in L3 development by daily feeding was less in the second experiment than in the first experiment. Daily fungal spore feeding provided more consistent larval reduction than intermittant feeding (every second or third day). When fed daily under controlled conditions, D. flagrans

  8. Dose classification scheme for digital imaging techniques in diagnostic radiology

    International Nuclear Information System (INIS)

    Hojreh, A.

    2002-04-01

    Purpose: image quality in diagnostic radiology is determined in crucial extent by the signal-noise-ratio, which is proportional to the applied x-ray dose. Onward technological developments in the diagnostic radiology are therefore frequently connected with a dose increase, which subjectively is hardly or even not perceptible. The aim of this work was to define reproducible standards for image quality as a function of dose and expected therapeutical consequence in case of computed tomography of the paranasal sinuses and the upper and lower jaw (dental CT), whereby practical-clinical purposes are considered. Materials and methods: the image quality of computed tomography of the paranasal sinuses and dental CT was determined by standard deviation of the CT-numbers (pixel noise) in a region of interest of the phantom of American Association of Physicists in Medicine (AAPM phantom) and additionally in the patients CT images. The diagnostic quality of the examination was classified on the basis of patients CT images in three dose levels (low dose, standard dose and high dose). Results: the pixel noise of CT of the paranasal sinuses with soft tissue reconstruction amounts to 19.3 Hounsfield units (HU) for low dose, 8.8 HU for standard dose, and below 8 HU for high dose. The pixel noise of the dental CT with bone (high resolution) reconstruction amounts to 344 HU for low dose, 221 HU for standard dose, and below 200 HU for high dose. Suitable indications for low dose CT are the scanning of body regions with high contrast differences, like the bony delimitations of air-filled spaces of the facial bones, and radiological follow-up examinations with dedicated questions such as axis determination in dental implantology, as well as the images of objects with small diameter such as in case of children. The standard dose CT can be recommended for all cases, in which precise staging of the illness plays an indispensable role for the diagnosis and therapy planning. With high dose

  9. Radiotherapy reference dose audit in the United Kingdom by the National Physical Laboratory: 20 years of consistency and improvements

    Directory of Open Access Journals (Sweden)

    Russell A.S. Thomas

    2017-07-01

    Conclusions: The introduction of the 2003 electron code of practice based on absorbed dose to water decreased the difference between absolute dose measurements by the centre and NPL. The use of a single photon code of practice over the period of measurements has contributed to a reduction in measurement variation. Within the clinical setting, on-site audit visits have been shown to identify areas of improvement for determining and implementing absolute dose calibrations.

  10. Hypothalamic-pituitary-adrenal (HPA) axis suppression after treatment with glucocorticoid therapy for childhood acute lymphoblastic leukaemia

    NARCIS (Netherlands)

    Gordijn, Maartje S.; Gemke, Reinoud J. B. J.; van Dalen, Elvira C.; Rotteveel, Joost; Kaspers, Gertjan J. L.

    2012-01-01

    Background Glucocorticoids play a major role in the treatment of acute lymphoblastic leukaemia (ALL). However, supraphysiological doses may cause suppression of the hypothalamic-pituitary-adrenal (HPA) axis. HPA axis suppression resulting in reduced cortisol response may cause an impaired stress

  11. Hypothalamic-pituitary-adrenal (HPA) axis suppression after treatment with glucocorticoid therapy for childhood acute lymphoblastic leukaemia

    NARCIS (Netherlands)

    Gordijn, Maartje S.; Rensen, Niki; Gemke, Reinoud J. B. J.; van Dalen, Elvira C.; Rotteveel, Joost; Kaspers, Gertjan J. L.

    2015-01-01

    Glucocorticoids play a major role in the treatment of acute lymphoblastic leukaemia (ALL). However, supraphysiological doses can suppress the hypothalamic-pituitary-adrenal (HPA) axis. HPA axis suppression resulting in reduced cortisol response may cause an impaired stress response and an inadequate

  12. Hypothalamic-pituitary-adrenal (HPA) axis suppression after treatment with glucocorticoid therapy for childhood acute lymphoblastic leukaemia

    NARCIS (Netherlands)

    Rensen, Niki; Gemke, Reinoud J. B. J.; van Dalen, Elvira C.; Rotteveel, Joost; Kaspers, Gertjan J. L.

    2017-01-01

    Glucocorticoids play a major role in the treatment of acute lymphoblastic leukaemia (ALL). However, supraphysiological doses can suppress the hypothalamic-pituitary-adrenal (HPA) axis. HPA axis suppression resulting in reduced cortisol response may cause an impaired stress response and an inadequate

  13. Dose-to-man studies

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Dose-to-Man Studies focused on developing computer data handling and computer modules which permit easy, rapid assessment of the dose to southeastern United States populations from routine or accidental releases of radionuclides to atmospheric and stream systems

  14. Anterior fixation of the axis.

    Science.gov (United States)

    Traynelis, Vincent C; Fontes, Ricardo B V

    2010-09-01

    Although anterior fixation of the axis is not commonly performed, plate fixation of C2 is an important technique for treating select upper cervical traumatic injuries and is also useful in the surgical management of spondylosis. To report the technique and outcomes of C2 anterior plate fixation for a series of patients in which the majority presented with symptomatic degenerative spondylosis. Forty-six consecutive patients underwent single or multilevel fusions over a 7-year period; 30 of these had advanced degenerative disease manifested by myelopathy or deformity. Exposure was achieved with rostral extension of the standard anterior cervical exposure via careful soft tissue dissection, mobilization of the superior thyroid artery, and the use of a table-mounted retractor. It was not necessary to remove the submandibular gland, section the digastric muscle, or make additional skin incisions. Screws were placed an average of 4.6 mm (+/- 2.3 mm) from the inferior C2 endplate with a mean sagittal trajectory of 15.7 degrees (+/- 7.6 degrees). Short- and long-term procedure-related mortality was 4.4%, and perioperative morbidity was 8.9%. Patients remained intubated an average of 2.5 days following surgery. Dysphagia was initially reported by 15.2% of patients but resolved by the 8th postoperative week in all patients. Arthrodesis was achieved in all patients available for long-term follow-up. Multilevel fusions were not associated with longer hospitalization or morbidity. Anterior plate fixation of the axis for degenerative disease can be accomplished with acceptable morbidity employing an extension of the standard anterolateral route.

  15. Measurement of dosimetric parameters and dose verification in stereotactic radiosurgery (SRS)

    International Nuclear Information System (INIS)

    Reduan Abdullah; Nik Ruzman Nik Idris; Ahmad Lutfi Yusof; Mazurawati Mohamed

    2013-01-01

    Full-text: The purpose of this study was to measure the dosimetric parameters for small photon beams to be used as input data treatment planning computer system (TPS) and to verify dose calculated by TPS in Stereotactic Radiosurgery (SRS) procedure. The beam data required were Percentage Depth Dose (PDD), Off-axis Ratio (OAR), and Scatter Factor of Relative Output Factor. Small beams of 5 mm to 45 mm diameter circular cone collimators used in SRS were utilized for beam data measurements measured using pinpoint 3D ionization chamber (0.016 cc). For second part of this study, we reported the important quality assurance (QA) procedures before SRS treatment that influenced the dose delivery. These QA procedures consist of measurements on the accuracy in target localization and room laser alignment. The dose calculated to be delivered for treatment was verified using pinpoint 3D ionization chamber and TLD 100H. The mean deviation of measured dose using TLD 100H compared to calculated dose was 3.37 %. Beside that, pinpoint ionization 3D chamber give more accurate results of dose compared to TLD 100H. The measured dose using pinpoint 3D ionization chamber are good agreement with calculated dose by TPS with deviation of 2.17 %. The results are acceptable such as recommended by International Commission on Radiation Units and Measurements (ICRU) Report No. 50 (1993) that dose delivered to the target volume must be within ±5 % error. (author)

  16. SU-E-T-366: Estimation of Whole Body Dose From Cranial Irradiation From C and Perfexion Series Gamma Knife Units

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, S [Indiana University Health Methodist Hospital, Indianapolis, IN (United States); Indiana University School of Medicine, Indianapolis, IN, University Hospitals Case Medical Center, Cleaveland, OH (United States); Andersen, A; Lulu, B; Das, I [Indiana University School of Medicine, Indianapolis, IN, University Hospitals Case Medical Center, Cleaveland, OH (United States); Cheng, C

    2015-06-15

    Purpose: The Leksell Gamma Knife (GK) B & C series contains 201 Cobalt-60 sources with a helmet. The new model, Perfexion uses 192 Cobalt-60 sources without a helmet; using IRIS system for collimation and stereotactic guidance to deliver SRS to brain tumors. Relative dose to extracranial organs at risk (OARs) is measured in phantom in this study for Perfexion and C-series GK. Materials & Methods: Measurements were performed in a Rando anthropomorphic phantom on both systems using a large ion chamber (Keithley-175) for each collimator. The Keithley-175 cc ion chamber was sandwiched between phantom slices at various locations in the phantom to correspond to different extracranial OARs (thyroid, heart, kidney, ovary and testis, etc.) The dose measurement was repeated with OSL detectors for each position and collimator. Results: A large variation is observed in the normalized dose between these two systems. The dose beyond the housing falls off exponentially for Perfexion. Dose beyond the C-series GK housing falls off exponentially from 0–20cm then remains relatively constant from 20–40cm and again falls off with distance but less rapidly. The variation of extracranial dose with distance for each collimator is found to be parallel to each other for both systems. Conclusion: Whole body dose is found to vary significantly between these systems. It is important to measure the extracranial dose, especially for young patients. It is estimated that dose falls off exponentially from the GK housing and is about 1% for large collimators at 75 cm. The dose is two-orders of magnitude smaller for the 4mm collimator. However, this small dose for patient may be significant radiologically.

  17. United States Air Force Academy (USAFA) Vertical Axis Wind Turbine.

    Science.gov (United States)

    1980-09-01

    Rotors, SAND76-0131. Albuquerque: July 1977. 10. Oliver, R.C. and P.R. Nixon. "Design Procedure for Coupling Savonius and Darrieus Wind Turbines ", Air...May 17-20, 1976. -65- 16. Blackwell, B.F., R.E. Sheldahl, and L.V. Feltz. Wind Tunnel Performance Data for the Darrieus Wind Turbine with NACA 0012...a 5.8 m/s (13 mph) wind . At 100 rpm, the Darrieus turbine would be fully self-sustaining and acceleration would continue to an operating tip speed

  18. SU-F-BRD-15: The Impact of Dose Calculation Algorithm and Hounsfield Units Conversion Tables On Plan Dosimetry for Lung SBRT

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, L; Yorke, E; Lim, S; Mechalakos, J; Rimner, A [Memorial Sloan-Kettering Cancer Center, NY, NY (United States)

    2014-06-15

    Purpose: To assess dosimetric differences in IMRT lung stereotactic body radiotherapy (SBRT) plans calculated with Varian AAA and Acuros (AXB) and with vendor-supplied (V) versus in-house (IH) measured Hounsfield units (HU) to mass and HU to electron density conversion tables. Methods: In-house conversion tables were measured using Gammex 472 density-plug phantom. IMRT plans (6 MV, Varian TrueBeam, 6–9 coplanar fields) meeting departmental coverage and normal tissue constraints were retrospectively generated for 10 lung SBRT cases using Eclipse Vn 10.0.28 AAA with in-house tables (AAA/IH). Using these monitor units and MLC sequences, plans were recalculated with AAA and vendor tables (AAA/V) and with AXB with both tables (AXB/IH and AXB/V). Ratios to corresponding AAA/IH values were calculated for PTV D95, D01, D99, mean-dose, total and ipsilateral lung V20 and chestwall V30. Statistical significance of differences was judged by Wilcoxon Signed Rank Test (p<0.05). Results: For HU<−400 the vendor HU-mass density table was notably below the IH table. PTV D95 ratios to AAA/IH, averaged over all patients, are 0.963±0.073 (p=0.508), 0.914±0.126 (p=0.011), and 0.998±0.001 (p=0.005) for AXB/IH, AXB/V and AAA/V respectively. Total lung V20 ratios are 1.006±0.046 (p=0.386), 0.975±0.080 (p=0.514) and 0.998±0.002 (p=0.007); ipsilateral lung V20 ratios are 1.008±0.041(p=0.284), 0.977±0.076 (p=0.443), and 0.998±0.018 (p=0.005) for AXB/IH, AXB/V and AAA/V respectively. In 7 cases, ratios to AAA/IH were within ± 5% for all indices studied. For 3 cases characterized by very low lung density and small PTV (19.99±8.09 c.c.), PTV D95 ratio for AXB/V ranged from 67.4% to 85.9%, AXB/IH D95 ratio ranged from 81.6% to 93.4%; there were large differences in other studied indices. Conclusion: For AXB users, careful attention to HU conversion tables is important, as they can significantly impact AXB (but not AAA) lung SBRT plans. Algorithm selection is also important for

  19. Treatment Dosing Patterns and Clinical Outcomes for Patients with Type 2 Diabetes Starting or Switching to Treatment with Insulin Glargine (300 Units per Milliliter) in a Real-World Setting: A Retrospective Observational Study.

    Science.gov (United States)

    Gupta, Shaloo; Wang, Hongwei; Skolnik, Neil; Tong, Liyue; Liebert, Ryan M; Lee, Lulu K; Stella, Peter; Cali, Anna; Preblick, Ronald

    2018-01-01

    Usage patterns and effectiveness of a longer-acting formulation of insulin glargine at a strength of 300 units per milliliter (Gla-300) have not been studied in real-world clinical practice. This study evaluated differences in dosing and clinical outcomes before and after Gla-300 treatment initiation in patients with type 2 diabetes starting or switching to treatment with Gla-300 to assess whether the benefits observed in clinical trials translate into real-world settings. This was a retrospective observational study using medical record data obtained by physician survey for patients starting treatment with insulin glargine at a strength of 100 units per milliliter (Gla-100) or Gla-300, or switching to treatment with Gla-300 from treatment with another basal insulin (BI). Differences in dosing and clinical outcomes before versus after treatment initiation or switching were examined by generalized linear mixed-effects models. Among insulin-naive patients starting BI treatment, no difference in the final titrated dose was observed in patients starting Gla-300 treatment versus those starting Gla-100 treatment [least-squares (LS) mean 0.43 units per kilogram vs 0.44 units per kilogram; P = 0.77]. Both groups had significant hemoglobin A 1c level reductions (LS mean 1.21 percentage points for Gla-300 and 1.12 percentage points for Gla-100 ; both P per kilogram before switch vs 0.58 units per kilogram after switch; P = 0.02). The mean hemoglobin A 1c level was significantly lower after switching than before switching (adjusted difference - 0.95 percentage points, 95% CI - 1.13 to - 0.78 percentage points ; P per patient-year were significantly lower (relative risk 0.17, 95% CI 0.11-0.26; P < 0.0001). Insulin-naive patients starting Gla-300 treatment had fewer hypoglycemic events, a similar hemoglobin A 1c level reduction, and no difference in insulin dose versus patients starting Gla-100 treatment. Patients switching to Gla-300 treatment from treatment with

  20. Programmatic Environmental Impact Statement: related to decontamination and disposal of radioactive wastes resulting from March 28, 1979 accident Three Mile Island Nuclear Station, Unit 2 (Docket No. 50-320). Final supplement dealing with occupational radiation dose. Supplement No. 1

    International Nuclear Information System (INIS)

    1984-10-01

    In accordance with the National Environmental Policy Act, the Programmatic Environmental Impact Statement Related to Decontamination and Disposal of Radioactive Wastes Resulting from March 28, 1979 Accident Three Mile Island Nuclear Station, Unit 2 has been supplemented. The supplement was required because current information indicates that cleanup may entail substantially more occupational radiation dose to the cleanup work force than originally anticipated. Cleanup was originally estimated to result in from 2000 to 8000 person-rem of occupational radiation dose. Although nearly 2000 person-rem have resulted from cleanup operations performed up to now, current estimates now indicate that between 13,000 and 46,000 person-rem are expected to be required. Alternative cleanup methods considered in the supplement either did not result in appreciable dose savings or were not known to be technically feasible

  1. Programmatic environmental impact statement related to decontamination and disposal of radioactive wastes resulting from March 28, 1979 accident, Three Mile Island Nuclear Station, Unit 2 (Docket No. 50-320). Draft supplement dealing with occupational radiation dose. Supplement No. 1

    International Nuclear Information System (INIS)

    1983-12-01

    In accordance with the National Environmental Policy Act, the Programmatic Environmental Impact Statement Related to Decontamination and Disposal of Radioactive Waste for the 1979 Accident at Three Mile Island Nuclear Station Unit 2 has been supplemented. The supplement was required because current information indicates that cleanup will entail substantially more occupational radiation dose to the cleanup work force than originally anticipated. Cleanup was originally estimated to result in from 2000 to 8000 person-rem of occupational radiation dose. Although only 1700 person-rem have resulted from cleanup operations performed up to now, current estimates now indicate that between 13,000 and 46,000 person-rem are expected to be required. Alternate cleanup methods considered in the supplement either did not result in appreciable dose savings or were not known to be technically feasible

  2. Mitochondrial–Lysosomal Axis in Acetaminophen Hepatotoxicity

    Directory of Open Access Journals (Sweden)

    Anna Moles

    2018-05-01

    Full Text Available Acetaminophen (APAP toxicity is the most common cause of acute liver failure and a major indication for liver transplantion in the United States and Europe. Although significant progress has been made in understanding the molecular mechanisms underlying APAP hepatotoxicity, there is still an urgent need to find novel and effective therapies against APAP-induced acute liver failure. Hepatic APAP metabolism results in the production of the reactive metabolite N-acetyl-p-benzoquinone imine (NAPQI, which under physiological conditions is cleared by its conjugation with glutathione (GSH to prevent its targeting to mitochondria. APAP overdose or GSH limitation leads to mitochondrial NAPQI-protein adducts formation, resulting in oxidative stress, mitochondrial dysfunction, and necrotic cell death. As mitochondria are a major target of APAP hepatotoxicity, mitochondrial quality control and clearance of dysfunctional mitochondria through mitophagy, emerges as an important strategy to limit oxidative stress and the engagement of molecular events leading to cell death. Recent evidence has indicated a lysosomal–mitochondrial cross-talk that regulates APAP hepatotoxicity. Moreover, as lysosomal function is essential for mitophagy, impairment in the fusion of lysosomes with autophagosomes-containing mitochondria may compromise the clearance of dysfunctional mitochondria, resulting in exacerbated APAP hepatotoxicity. This review centers on the role of mitochondria in APAP hepatotoxicity and how the mitochondrial/lysosomal axis can influence APAP-induced liver failure.

  3. A study of the annual doses to man from routine gaseous effluent releases of the Philippine Nuclear Power Plant Unit 1 (PNPP-1)

    International Nuclear Information System (INIS)

    Noriel, M.C.J.

    1983-01-01

    Individual and population integrated doses from radioactive gaseous releases of the Philippine Nuclear Power Plant 1 (PNPP-1) were calculated using a modified GASPAR Code. Input data consisted of meteorological and site data gathered from the PNPP-1 Final Analysis Report (FASR) population and agricultural data from the National Economic and Development Authority (NEDA) and the National Census and Statistics Office (NCSO). Usage factors were calculated based on Food and Nutrition Research Institute (FNRI) recommended dietary allowances for Filipinos. Results of population integrated dose calculations were used in identifying the critical nuclides, the critical body organs, and the critical pathway. Results from individual dose calculation were used in determining compliance with the dose limits set forth in Appendix D of Part 7 Code of Philippine Atomic Energy Commission (PAEC) regulations. (Author). 23 tabs.; 5 figs

  4. Methods of determining the effective dose in dental radiology

    International Nuclear Information System (INIS)

    Thilander-Klang, A.; Helmrot, E.

    2010-01-01

    A wide variety of X-ray equipment is used today in dental radiology, including intra-oral, ortho-pan-tomographic, cephalo-metric, cone-beam computed tomography (CBCT) and computed tomography (CT). This raises the question of how the radiation risks resulting from different kinds of examinations should be compared. The risk to the patient is usually expressed in terms of effective dose. However, it is difficult to determine its reliability, and it is difficult to make comparisons, especially when different modalities are used. The classification of the new CBCT units is also problematic as they are sometimes classified as CT units. This will lead to problems in choosing the best dosimetric method, especially when the examination geometry resembles more on an ordinary ortho-pan-tomographic examination, as the axis of rotation is not at the centre of the patient, and small radiation field sizes are used. The purpose of this study was to present different methods for the estimation of the effective dose from the equipment currently used in dental radiology, and to discuss their limitations. The methods are compared based on commonly used measurable and computable dose quantities, and their reliability in the estimation of the effective dose. (authors)

  5. Paediatric dose display

    International Nuclear Information System (INIS)

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

    1984-01-01

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

  6. An environmental dose experiment

    Science.gov (United States)

    Peralta, Luis

    2017-11-01

    Several radiation sources worldwide contribute to the delivered dose to the human population. This radiation also acts as a natural background when detecting radiation, for instance from radioactive sources. In this work a medium-sized plastic scintillation detector is used to evaluate the dose delivered by natural radiation sources. Calibration of the detector involved the use of radioactive sources and Monte Carlo simulation of the energy deposition per disintegration. A measurement of the annual dose due to background radiation to the body was then estimated. A dose value compatible with the value reported by the United Nations Scientific Committee on the Effects of Atomic Radiation was obtained.

  7. An environmental dose experiment

    International Nuclear Information System (INIS)

    Peralta, Luis

    2017-01-01

    Several radiation sources worldwide contribute to the delivered dose to the human population. This radiation also acts as a natural background when detecting radiation, for instance from radioactive sources. In this work a medium-sized plastic scintillation detector is used to evaluate the dose delivered by natural radiation sources. Calibration of the detector involved the use of radioactive sources and Monte Carlo simulation of the energy deposition per disintegration. A measurement of the annual dose due to background radiation to the body was then estimated. A dose value compatible with the value reported by the United Nations Scientific Committee on the Effects of Atomic Radiation was obtained. (paper)

  8. Individual doses control in the units of ministry of defence and ministry of interior and administration in the years 1986 - 2000

    International Nuclear Information System (INIS)

    Jazwinski, J.; Nowosielska, E.M.; Janiak, M.K.

    2003-01-01

    The aim of presented work was the assessment of occupational radiation exposure and its distribution among the workers of Ministry of Defence and Ministry of Interior and Administration in the years 1986 - 2000. the research was conducted on the basis of data collected by Laboratory of Radiological Inspection and Individual Doses Control, Department of Radiation Protection and Radiobiology Military Institute of Hygiene and Epidemiology, Warsaw, Poland. The workers occupationally exposed to radiation were divided into following groups: government department (Ministry of Defence or Ministry of Interior and Administration), according to the age (below 25, 26-35, 36-45, 46-55 and above 56 years old), sex, education, (elementary, secondary, university) or job (doctors, nurses, rtg technicians, etc.). The number of workers covered with individual doses control changed in Ministry of Defence from 689 (in 1986) to 1030 (in 2000), and in Ministry of Interior and Administration from 261 to 924 in the same period. The percent of workers, who received doses below 2 mSv per year varied in Ministry of Defence from 91,6% (in 1997) to 99,4% (in 1990), and in Ministry of Interior and Administration from 96,8% (in 1993) to 99,4 (in 2000). Almost 99% of workers occupationally exposed to radiation and covered with individual doses control received doses below 15 mSv, irrespective of year or department. The analysis of collected data revealed, that for a large majority of occupationally exposed workers the risk arising from contact with ionizing radiation is minimal (over 99% of workers covered with individual doses control received doses below 2 mSv per year), however there are critical groups of workers, for which the received equivalent doses were about 30 - 50 mSv. Increased doses of radiation, however not exceeding obligatory limits, are noticed for workers taking part in surgical operations in X radiation field, urologic operations and diagnostic and or working on several

  9. Vertical-axis turbine/propeller for ship propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Barkla, H.M.

    1984-01-01

    There are so many variables in the design and operating conditions of a vertical-axis turbine/propeller for the propulsion of a ship by wind that a preliminary study is offered, based on two simplified models. Study of a linear motion of blades in air and water shows optimum conditions for blade-speed and blade-incidence. Analysis of the second, cyclical model is simplified by the assumption of constant angles of incidence. While the logical superiority of the vertical-axis system, with its low transmission loss, may not alone give it the advantage over all other systems in upwind and downwind sailing, there are indications that in the beam wind it is in a class of its own; the Voith-Schneider-Type propeller then produces a thrust with a major component to windward, so that the combined unit leaves little or no athwartships force.

  10. Summary of tower designs for large horizontal axis wind turbines

    Science.gov (United States)

    Frederick, G. R.; Savino, J. M.

    1986-01-01

    Towers for large horizontal axis wind turbines, machines with a rotor axis height above 30 meters and rated at more than 500 kW, have varied in configuration, materials of construction, type of construction, height, and stiffness. For example, the U.S. large HAWTs have utilized steel truss type towers and free-standing steel cylindrical towers. In Europe, the trend has been to use only free-standing and guyed cylindrical towers, but both steel and reinforced concrete have been used as materials of construction. These variations in materials of construction and type of construction reflect different engineering approaches to the design of cost effective towers for large HAWTs. Tower designs are the NASA/DOE Mod-5B presently being fabricated. Design goals and requirements that influence tower configuration, height and materials are discussed. In particular, experiences with United States large wind turbine towers are elucidated. Finally, current trends in tower designs for large HAWTs are highlighted.

  11. On the accuracy of self-made dose planning system based on the static field measurements of cobalt unit Theratron 780C

    International Nuclear Information System (INIS)

    Treer, T.; Polgar, I.

    1995-01-01

    In connection with the installation of the new Theratron 780C cobalt unit the authors demonstrate that the planning program developed in Pecs 8 years ago can be used even for the new cobalt unit. The computed results are in good agreement with the measurements made by the PTW MP3 water phantom using the Mephysto program. (N.T.) 3 refs., 4 figs

  12. An evaluation of dose/unit area and time as key factors influencing the elicitation capacity of methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) in MCI/MI-allergic patients

    DEFF Research Database (Denmark)

    Zachariae, Claus; Lerbaek, Anne; McNamee, Pauline M

    2006-01-01

    Methylchloroisothiazolinone and methylisothiazolinone (MCI/MI) contact allergy affects 1-3% of patch-tested patients in European centres. The aim of the present study was to evaluate the importance of the factors--time and concentration (dose/per unit area)--in the elicitation capacity by means...... (2 p.p.m.) of MCI/MI/unit area of the skin for 4 weeks. After a wash-out period of at least 4 weeks, the subjects were exposed to 0.094 microg/cm2 (7.5 p.p.m.) of MCI/MI/unit area of the skin for 4 weeks. The study showed the importance of both time and exposure in the elicitation process...

  13. Tissue explant coculture model of the hypothalamic-pituitary-gonadal-liver axis of the fathead minnow (Pimephales promelas) as a predictive tool for endocrine disruption.

    Science.gov (United States)

    Johnston, Theresa K; Perkins, Edward; Ferguson, Duncan C; Cropek, Donald M

    2016-10-01

    Endocrine-disrupting compounds (EDCs) can impact the reproductive system by interfering with the hypothalamic-pituitary-gonadal (HPG) axis. Although in vitro testing methods have been developed to screen chemicals for endocrine disruption, extrapolation of in vitro responses to in vivo action shows inconsistent accuracy. The authors describe a tissue coculture of the fathead minnow (Pimephales promelas) HPG axis and liver (HPG-L) as a tissue explant model that mimics in vivo results. Brain (hypothalamus), pituitary, gonad, and liver tissue explants from adult fish were examined for function both individually and in coculture to determine combinations and conditions that could replicate in vivo behavior. Only cocultures had the ability to respond to an EDC, trenbolone, similarly to in vivo studies, based on estradiol, testosterone, and vitellogenin production trends, where lower exposure doses suppressed hormone production but higher doses increased production, resulting in distinctive U-shaped curves. These data suggest that a coculture system with all components of the HPG-L axis can be used as a link between in vitro and in vivo studies to predict endocrine system disruption in whole organisms. This tissue-based HPG-L system acts as a flexible deconstructed version of the in vivo system for better control and examination of the minute changes in system operation and response on EDC exposure with options to isolate, interrogate, and recombine desired components. Environ Toxicol Chem 2016;35:2530-2541. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America.

  14. Effective dose per unit fluence calculated for adults and a 7 year old girl in broad antero-posterior beams of monoenergetic electrons of 0.1 to 10 MeV

    International Nuclear Information System (INIS)

    Schultz, F.W.; Zoetelief, J.

    1997-01-01

    For broad antero-posterior beams of monoenergetic (0.1-10 MeV) electrons, organ doses per unit fluence were computed through Monte Carlo simulation with reference to male and female adult and a 7 year old girl. Effective doses (E) per unit fluence were calculated for the three phantoms and for an average adult. E increases from about 8 x 10 -14 to about 1.2 x 10 -10 Sv.cm 2 with increasing electron energy. Uncertainties were (often much) better than 6% for the adults, and 18% for the child. E as calculated for the average adult may be used for both males and females as under- or overestimations stay within 25% from E for the average adult. The child's radiation risk is underestimated for electron energies in the range of 0.6 to 3 MeV. This underestimation up to a factor of about 20 is unacceptable for radiological protection purposes. The present results were compared with literature data on operational quantities associated with radiation hazard from weakly penetrating radiation. Neither directional nor personal dose equivalent appears to be a realistic quantity in this case. Both would yield an unnecessarily large safety factor for radiological protection. (author)

  15. Automated treatment planning for a dedicated multi-source intra-cranial radiosurgery treatment unit accounting for overlapping structures and dose homogeneity

    Energy Technology Data Exchange (ETDEWEB)

    Ghobadi, Kimia; Ghaffari, Hamid R. [Department of Mechanical and Industrial Engineering, University of Toronto, Ontario M5S 3G8 (Canada); Aleman, Dionne M. [Department of Mechanical and Industrial Engineering, University of Toronto, Ontario M5S 3G8 (Canada); Institute of Health Policy, Management and Evaluation, University of Toronto, Ontario M5T 3M6 (Canada); Techna Institute, University Health Network, Ontario M5G 1P5 (Canada); Jaffray, David A. [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Ontario M5T 2M9 (Canada); Department of Radiation Oncology, University of Toronto, Ontario M5S 3E2 (Canada); Department of Medical Biophysics, University of Toronto, Ontario M5G 2M9 (Canada); Institute of Biomaterial and Biomedical Engineering, University of Toronto, Ontario M5S 2J7 (Canada); Techna Institute, University Health Network, Ontario M5G 1P5 (Canada); Ontario Cancer Institute, Ontario M5G 0A3 (Canada); Ruschin, Mark [Department of Medical Physics, Odette Cancer Centre, Toronto, Ontario M4N 3M5 (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3E2 (Canada)

    2013-09-15

    Purpose: The purpose of this work is to advance the two-step approach for Gamma Knife{sup ®} Perfexion™ (PFX) optimization to account for dose homogeneity and overlap between the planning target volume (PTV) and organs-at-risk (OARs).Methods: In the first step, a geometry-based algorithm is used to quickly select isocentre locations while explicitly accounting for PTV-OARs overlaps. In this approach, the PTV is divided into subvolumes based on the PTV-OARs overlaps and the distance of voxels to the overlaps. Only a few isocentres are selected in the overlap volume, and a higher number of isocentres are carefully selected among voxels that are immediately close to the overlap volume. In the second step, a convex optimization is solved to find the optimal combination of collimator sizes and their radiation duration for each isocentre location.Results: This two-step approach is tested on seven clinical cases (comprising 11 targets) for which the authors assess coverage, OARs dose, and homogeneity index and relate these parameters to the overlap fraction for each case. In terms of coverage, the mean V{sub 99} for the gross target volume (GTV) was 99.8% while the V{sub 95} for the PTV averaged at 94.6%, thus satisfying the clinical objectives of 99% for GTV and 95% for PTV, respectively. The mean relative dose to the brainstem was 87.7% of the prescription dose (with maximum 108%), while on average, 11.3% of the PTV overlapped with the brainstem. The mean beam-on time per fraction per dose was 8.6 min with calibration dose rate of 3.5 Gy/min, and the computational time averaged at 205 min. Compared with previous work involving single-fraction radiosurgery, the resulting plans were more homogeneous with average homogeneity index of 1.18 compared to 1.47.Conclusions: PFX treatment plans with homogeneous dose distribution can be achieved by inverse planning using geometric isocentre selection and mathematical modeling and optimization techniques. The quality of the

  16. SU-F-SPS-02: Accuracy of the Small Field Dosimetry Using the Monte Carlo and Sequential Dose Calculation Algorithms of Multiplan Treatment Planning System Within and Beyond Heterogeneous Media for Cyberknife M6 Unit

    Energy Technology Data Exchange (ETDEWEB)

    Serin, E.; Codel, G.; Mabhouti, H.; Cebe, M.; Sanli, E.; Pacaci, P.; Kucuk, N.; Kucukmorkoc, E.; Doyuran, M.; Canoglu, D.; Altinok, A.; Acar, H.; Caglar Ozkok, H. [Medipol University, Istanbul, Istanbul (Turkey)

    2016-06-15

    Purpose: In small field geometries, the electronic equilibrium can be lost, making it challenging for the dose-calculation algorithm to accurately predict the dose, especially in the presence of tissue heterogeneities. In this study, dosimetric accuracy of Monte Carlo (MC) advanced dose calculation and sequential algorithms of Multiplan treatment planning system were investigated for small radiation fields incident on homogeneous and heterogeneous geometries. Methods: Small open fields of fixed cones of Cyberknife M6 unit 100 to 500 mm2 were used for this study. The fields were incident on in house phantom containing lung, air, and bone inhomogeneities and also homogeneous phantom. Using the same film batch, the net OD to dose calibration curve was obtained using CK with the 60 mm fixed cone by delivering 0- 800 cGy. Films were scanned 48 hours after irradiation using an Epson 1000XL flatbed scanner. The dosimetric accuracy of MC and sequential algorithms in the presence of the inhomogeneities was compared against EBT3 film dosimetry Results: Open field tests in a homogeneous phantom showed good agreement between two algorithms and film measurement For MC algorithm, the minimum gamma analysis passing rates between measured and calculated dose distributions were 99.7% and 98.3% for homogeneous and inhomogeneous fields in the case of lung and bone respectively. For sequential algorithm, the minimum gamma analysis passing rates were 98.9% and 92.5% for for homogeneous and inhomogeneous fields respectively for used all cone sizes. In the case of the air heterogeneity, the differences were larger for both calculation algorithms. Overall, when compared to measurement, the MC had better agreement than sequential algorithm. Conclusion: The Monte Carlo calculation algorithm in the Multiplan treatment planning system is an improvement over the existing sequential algorithm. Dose discrepancies were observed for in the presence of air inhomogeneities.

  17. SU-F-SPS-02: Accuracy of the Small Field Dosimetry Using the Monte Carlo and Sequential Dose Calculation Algorithms of Multiplan Treatment Planning System Within and Beyond Heterogeneous Media for Cyberknife M6 Unit

    International Nuclear Information System (INIS)

    Serin, E.; Codel, G.; Mabhouti, H.; Cebe, M.; Sanli, E.; Pacaci, P.; Kucuk, N.; Kucukmorkoc, E.; Doyuran, M.; Canoglu, D.; Altinok, A.; Acar, H.; Caglar Ozkok, H.

    2016-01-01

    Purpose: In small field geometries, the electronic equilibrium can be lost, making it challenging for the dose-calculation algorithm to accurately predict the dose, especially in the presence of tissue heterogeneities. In this study, dosimetric accuracy of Monte Carlo (MC) advanced dose calculation and sequential algorithms of Multiplan treatment planning system were investigated for small radiation fields incident on homogeneous and heterogeneous geometries. Methods: Small open fields of fixed cones of Cyberknife M6 unit 100 to 500 mm2 were used for this study. The fields were incident on in house phantom containing lung, air, and bone inhomogeneities and also homogeneous phantom. Using the same film batch, the net OD to dose calibration curve was obtained using CK with the 60 mm fixed cone by delivering 0- 800 cGy. Films were scanned 48 hours after irradiation using an Epson 1000XL flatbed scanner. The dosimetric accuracy of MC and sequential algorithms in the presence of the inhomogeneities was compared against EBT3 film dosimetry Results: Open field tests in a homogeneous phantom showed good agreement between two algorithms and film measurement For MC algorithm, the minimum gamma analysis passing rates between measured and calculated dose distributions were 99.7% and 98.3% for homogeneous and inhomogeneous fields in the case of lung and bone respectively. For sequential algorithm, the minimum gamma analysis passing rates were 98.9% and 92.5% for for homogeneous and inhomogeneous fields respectively for used all cone sizes. In the case of the air heterogeneity, the differences were larger for both calculation algorithms. Overall, when compared to measurement, the MC had better agreement than sequential algorithm. Conclusion: The Monte Carlo calculation algorithm in the Multiplan treatment planning system is an improvement over the existing sequential algorithm. Dose discrepancies were observed for in the presence of air inhomogeneities.

  18. The lowest-dose, extended-cycle combined oral contraceptive pill with continuous ethinyl estradiol in the United States: a review of the literature on ethinyl estradiol 20 µg/levonorgestrel 100 µg + ethinyl estradiol 10 µg

    Directory of Open Access Journals (Sweden)

    Sheila Krishnan

    2010-08-01

    Full Text Available Sheila Krishnan, Jessica KileyDepartment of Obstetrics and Gynecology, Northwestern University, Chicago, Illinois, USAAbstract: Extended-cycle oral contraceptives (OCs are increasing in popularity in the United States. A new extended-cycle OC that contains the lowest doses of ethinyl estradiol (EE and levonorgestrel (LNG + continuous EE throughout the cycle is now available. It provides 84 days of a low-dose, combined active pill containing levonorgestrel 100 µg and ethinyl estradiol 20 µg. Instead of 7 days of placebo following the active pills, the regimen delivers 7 days of ethinyl estradiol 10 µg. Existing studies reveal a similar efficacy and adverse effect profile compared with other extended-regimen OCs. Specifically, the unscheduled bleeding profile is similar to other extended-cycle OCs and improves with the increase in the duration of use. Although lower daily doses of hormonal exposure have potential benefit, to our knowledge, there are no published studies indicating that this specific regimen offers a lower incidence of hormone-related side effects or adverse events. In summary, this new extended-cycle OC provides patients a low-dose, extended-regimen OC option without sacrificing efficacy or tolerability.Keywords: continuous regimen, ethinyl estradiol, extended cycle, oral contraceptive

  19. In vivo dose estimations through transit signal measured with thimble chamber positioned along the central axis at electronic portal imaging device level in medical linear accelerator in carcinoma of the middle-third esophagus patients undergoing three-dimensional conformal radiotherapy.

    Science.gov (United States)

    Kumar, Putha Suman; Banerjee, S; Arun Kumar, E S; Srinivas, Challapalli; Vadhiraja, B M; Saxena, P U; Ravichandran, Ramamoorthy; Kasturi, Dinesh Pai

    2018-01-01

    This study presents a method to estimate midplane dose (D iso, transit ) in vivo from transit signal (S t ) measured with thimble ionization chamber in cancer of the middle-third esophagus patients treated with three-dimensional radiotherapy (RT). This detector is positioned at the level of electronic portal imaging device in the gantry of a medical linear accelerator. Efficacy of inhomogeneity corrections of three dose calculation algorithms available in XiO treatment planning system (TPS) for planned dose (for open fields) (D iso, TPS ) was studied with three heterogeneous phantoms. D iso, transit represents measured signal at transit point (S t ) far away correlating to dose at isocenter. A locally fabricated thorax phantom was used to measure the in vivo midplane dose (D iso, mid ) which was also estimated through S t . Thirteen patients with carcinoma of the middle-third esophagus treated with three-dimensional conformal RT were studied. S t was recorded (three times, with a gap of 5-6 fractions during the treatment) to estimate D iso, transit , which was compared with the doses calculated by TPS. The dose predictions by superposition algorithm were superior compared to the other algorithms. Percentage deviation of D iso, transit , D iso, mid with D iso, TPS combined all fields was 2.7 and -2.6%, respectively, with the thorax phantom. The mean percentage deviation with standard deviation of estimated D iso, transit with D iso, TPS observed in patients was within standard deviation -0.73% ±2.09% (n = 39). Midplane dose estimates in vivo using this method provide accurate determination of delivered dose in the middle-third esophagus RT treatments. This method could be useful in similar clinical circumstances for dose confirmation and documentation.

  20. Practical use of Gafchromic(®) EBT films in electron beams for in-phantom dose distribution measurements and monitor units verification.

    Science.gov (United States)

    El Barouky, Jad; Fournier-Bidoz, Nathalie; Mazal, Alejandro; Fares, Georges; Rosenwald, Jean-Claude

    2011-04-01

    The possibility of using the Gafchromic(®) EBT films parallel to incident electron beams was assessed in order to facilitate quality assurance tests for electron dose calculation algorithms. Calibration curves were made for electron energies of 6, 9 and 12MeV. A set-up was suggested for EBT film irradiation parallel to the beam, and the dose measurements were compared to Ionization Chamber (IC) measurements in standard and small electrons beams. A more complex Quality Assurance (QA) set-up was performed with the cylindrical CARPET(®) phantom in order to test our Treatment Planning System (TPS) (Eclipse, Varian Medical Systems, Palo Alto, California) for the clinical situation of a chest wall electron beam therapy. Two dimensional dose distribution and gamma index results were compared to the calculated distribution given by the TPS. The reproducibility was found to be better than 1.5%. We found that applying strong pressure and aligning carefully the film edge with the phantom surface, as recommended for radiographic films, did not completely eliminate the air gap effect. Adding an ultrasound transmission gel and 2 complementary EBT films on the surface gave satisfactory results. The absolute dose for the reference 10×10cm(2) field was always within 1% of IC measurements and for smaller elongated fields (5×10, 4×10 and 3×10cm(2)) the mean difference was -1.4% for the three energies. The mean difference with the IC measurements in R(100), R(90) and R(50) was 0.9mm for all fields and for the three energies. The mean difference in the width of the 90% and the 50% isodoses at R(100) was 0.6mm. With the CARPET(®) phantom set-up very good agreement was found in the 2D dose distribution; 99% of the points satisfied the γdose distribution if ultrasound gel and overlying perpendicular films are added on the phantom surface. Copyright © 2010 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  1. Adaptive Response in Female Modeling of the Hypothalamic-pituitary-gonadal Axis

    Science.gov (United States)

    Exposure to endocrine disrupting chemicals can affect reproduction and development in both humans and wildlife. We are developing a mechanistic computational model of the hypothalamic-pituitary-gonadal (HPG) axis in female fathead minnows to predict dose-response and time-course ...

  2. Population dose estimation from a hypothetical release of 2.4 x 106 curies of noble gases and 1 x 104 curies of 131I at the Three Mile Island Nuclear Station, Unit 2

    International Nuclear Information System (INIS)

    Berger, C.D.; Lane, B.H.; Cotter, S.J.; Miller, C.W.; Glandon, S.R.

    1981-09-01

    Beginning on March 28, 1979, a sequence of events occurred at the Three Mile Island Nuclear Station Unit 2 (TMINS-2) nuclear power reactor which resulted in the accidental release of approximately 2.4 x 10 6 Ci of noble gases and 13 to 15 Ci 131 I. A comprehensive study of this incident has been reported by the President's Commission on the Accident at Three Mile Island. As part of this study, the Technical Assessment Task Group for the Commission addressed a series of alternative event scenarios, including the potential for a higher release of 131 I. As a continuation of this task, this report presents the estimated collective dose to the population within 50 miles of TMINS-2 from a hypothetical release of 2.4 x 10 6 Ci of noble gases and 1 x 10 4 Ci 131 I by the methodology of atmospheric dispersion modeling and population dose estimation through the inhalation, ingestion and immersion exposure pathways

  3. Electric power from vertical-axis wind turbines

    Science.gov (United States)

    Touryan, K. J.; Strickland, J. H.; Berg, D. E.

    1987-12-01

    Significant advancements have occurred in vertical axis wind turbine (VAWT) technology for electrical power generation over the last decade; in particular, well-proven aerodynamic and structural analysis codes have been developed for Darrieus-principle wind turbines. Machines of this type have been built by at least three companies, and about 550 units of various designs are currently in service in California wind farms. Attention is presently given to the aerodynamic characteristics, structural dynamics, systems engineering, and energy market-penetration aspects of VAWTs.

  4. UMAPRM: Uniformly sampling the medial axis

    KAUST Repository

    Yeh, Hsin-Yi Cindy

    2014-05-01

    © 2014 IEEE. Maintaining clearance, or distance from obstacles, is a vital component of successful motion planning algorithms. Maintaining high clearance often creates safer paths for robots. Contemporary sampling-based planning algorithms That utilize The medial axis, or The set of all points equidistant To Two or more obstacles, produce higher clearance paths. However, They are biased heavily Toward certain portions of The medial axis, sometimes ignoring parts critical To planning, e.g., specific Types of narrow passages. We introduce Uniform Medial Axis Probabilistic RoadMap (UMAPRM), a novel planning variant That generates samples uniformly on The medial axis of The free portion of Cspace. We Theoretically analyze The distribution generated by UMAPRM and show its uniformity. Our results show That UMAPRM\\'s distribution of samples along The medial axis is not only uniform but also preferable To other medial axis samplers in certain planning problems. We demonstrate That UMAPRM has negligible computational overhead over other sampling Techniques and can solve problems The others could not, e.g., a bug Trap. Finally, we demonstrate UMAPRM successfully generates higher clearance paths in The examples.

  5. X-rays, radiometers and skin unit dose. The development of measuring methods and measuring units for X radiation in medical physics from the beginning until the international standardization; X-Strahlen, Radiometer und Hauteinheitsdosis. Die Entwicklung der Messverfahren und Masseinheiten fuer Roentgenstrahlung in der medizinischen Physik von den Anfaengen bis zur internationalen Standardisierung

    Energy Technology Data Exchange (ETDEWEB)

    Glessmer-Junike, Simone

    2015-01-22

    X-rays, a special form of ionizing radiation, have been utilized in medicine and technology ever since their discovery at the end of 1895. However, the usage of X-rays made the development of measuring techniques necessary. Newly-developed measuring devices were at first called radiometers', but later the term dosimeter' has gained universal acceptance. The development of numerous dosimeters used in radiotherapy was accompanied by new units of measurement, each corresponding to its individual newly constructed dosimeter or method of measurement. While at first conversions between old and new units were performed, it later became clear that both within Germany and Europe units with similar names were used with different meanings, which was both incompatible and confusing. The first serious attempts of a standardization of units in Germany were made after the First World War, when the when the ionizing properties of X-rays was focused on for both measurements and unit definitions. Efforts towards an international standardization of units became successful in the mid-1920s when the Roentgen was defined as the universal unit. From the development described above, four stages of the evolution of radiation measurement and units in radiotherapy could be identified by means of comprehensive systematic research in printed publications. The first stage was the period of diagnostic application of X-rays, when tools for the determination of X-ray quality were designed. This stage progressed into that of therapeutic administration of X-rays shortly after, when instruments and units for the measurement of X-ray quantities (dose') were implemented. Due to the variety and diversity of measurement apparatus and units a third stage emerged, closely interconnected with the second. During the third stage, a nation-wide standardization was attempted in Germany. With the conclusion of this stage - the resolution of a unit for dose measurement in Germany - the stage of

  6. Comparison of absorbed-dose-to-water units for Co-60 and high-energy x-rays between PTB and LNE-LNHB

    International Nuclear Information System (INIS)

    Delaunay, F.; Gouriou, J.; Le Roy, M.; Ostrowsky, A.; Sommier, L.; Vermesse, D.; Kapsch, R.P.; Illemann, J.; Krauss, A.

    2012-01-01

    During the Euramet project JRP7 'External Beam Cancer Therapy', PTB and LNE-LNHB used primary standards to determine the absorbed dose to water under IMRT conditions (in small fields). PTB used a water calorimeter to determine the absorbed-dose-to-water references in 6 MV and 10 MV beams for field sizes of 10 cm * 10 cm and 3 cm * 3 cm while LNE-LNHB used graphite calorimeters in 6MV and 12MV beams for field sizes of 10 cm * 10 cm, 4 cm * 4 cm and 2 cm * 2 cm. The purpose of this study is to compare PTB and LNE-LNHB new absorbed-dose-to-water references. LNE-LNHB sent an Exradin A1SL ionization chamber traceable to its primary standard to the PTB for calibration in 60 Co and in linac beams and PTB sent a PTW 31010 ionization chamber traceable to its primary standard to LNE-LNHB for calibration in 60 Co and in linac beams. Calculated Sw,air will be used as beam quality specifier for the ionization chamber comparison at different field sizes. The standard uncertainties (k = 1) of PTB and LNE-LNHB calibration coefficients lie respectively between 0.25% ( 60 Co) and 0.40% (linac) and between 0.29% and 0.46%. PTB and LNE-LNHB absorbed-dose-to-water references developed for this project, based respectively on water calorimetry and on graphite calorimetry, agree within 1.5 standard deviations for field size of 10 cm * 10 cm down to 2 cm * 2 cm and for beams of 6 MV to 10 MV. (authors)

  7. Characterization of a multi-axis ion chamber array.

    Science.gov (United States)

    Simon, Thomas A; Kozelka, Jakub; Simon, William E; Kahler, Darren; Li, Jonathan; Liu, Chihray

    2010-11-01

    The aim of this work was to characterize a multi-axis ion chamber array (IC PROFILER; Sun Nuclear Corporation, Melbourne, FL, USA) that has the potential to simplify the acquisition of LINAC beam data. The IC PROFILER (or panel) measurement response was characterized with respect to radiation beam properties, including dose, dose per pulse, pulse rate frequency (PRF), and energy. Panel properties were also studied, including detector-calibration stability, power-on time, backscatter dependence, and the panel's agreement with water tank measurements [profiles, fractional depth dose (FDD), and output factors]. The panel's relative deviation was typically within (+/-) 1% of an independent (or nominal) response for all properties that were tested. Notable results were (a) a detectable relative field shape change of approximately 1% with linear accelerator PRF changes; (b) a large range in backscatter thickness had a minimal effect on the measured dose distribution (typically less than 1%); (c) the error spread in profile comparison between the panel and scanning water tank (Blue Phantom, CC13; IBA Schwarzenbruck, DE) was approximately (+/-) 0.75%. The ability of the panel to accurately reproduce water tank profiles, FDDs, and output factors is an indication of its abilities as a dosimetry system. The benefits of using the panel versus a scanning water tank are less setup time and less error susceptibility. The same measurements (including device setup and breakdown) for both systems took 180 min with the water tank versus 30 min with the panel. The time-savings increase as the measurement load is increased.

  8. Actuator assembly including a single axis of rotation locking member

    Science.gov (United States)

    Quitmeyer, James N.; Benson, Dwayne M.; Geck, Kellan P.

    2009-12-08

    An actuator assembly including an actuator housing assembly and a single axis of rotation locking member fixedly attached to a portion of the actuator housing assembly and an external mounting structure. The single axis of rotation locking member restricting rotational movement of the actuator housing assembly about at least one axis. The single axis of rotation locking member is coupled at a first end to the actuator housing assembly about a Y axis and at a 90.degree. angle to an X and Z axis providing rotation of the actuator housing assembly about the Y axis. The single axis of rotation locking member is coupled at a second end to a mounting structure, and more particularly a mounting pin, about an X axis and at a 90.degree. angle to a Y and Z axis providing rotation of the actuator housing assembly about the X axis. The actuator assembly is thereby restricted from rotation about the Z axis.

  9. PERMEABILITY OF SAVCIBEY DAM (BİLECİK AXIS LOCATION AND DESIGN OF GROUT CURTAIN

    Directory of Open Access Journals (Sweden)

    Mustafa Can Canoğlu

    2016-12-01

    Full Text Available This study comprise the design of the planned grout curtain in Savcıbey Dam (Söğüt/Bilecik in order to provide impermeability along the dam axis. Within the context of field studies, engineering geology map was generated, ground investigation drilling was realized and permeability tests were performed. Within the field studies, the joint conditions of the geological units (Triassic aged Bozuyük Metamorphic schists under the dam axis and its effect on permeability was observed considering the positions of the discontinuities with regard to the dam axis location. Orientation of discontinuities generally have strikes changing between N – S and NNE – SSW. 5 boreholes on dam axis, 2 boreholes on cofferdam, 3 boreholes on diversion tunnel and 2 boreholes on spillway total 245 m ground investigation borehole were drilled. In order to determine the permeability profile of dam axis and design the grout curtain, Lugeon tests in Bozuyük Metamorphic units observed in dam axis, falling head permeability tests in alluviums observed in thalveg and slope debris observed in right abutment were performed. Lugeon tests realized in Bozuyük Metamorphic units show that the unit is generally permeable and partly low permeable. Alluvium and slope debris are highly permeable. In addition, drilling works realized in dam axis shows that the augmentation of the weathering degree cause an increase of permeability in Triassic aged Bozüyük Metamorphic schists. As a result of these studies information about the permeability of Savcıbey Dam was collected and the grout curtain hole was designed. Accordingly, it is predicted that approximately 40 m depth of grout curtain from the stripping excavation with the depth of 1.50 m would prevent the possible leakages.

  10. Environmental stressors and epigenetic control of the hypothalamic-pituitary-adrenal-axis (HPA-axis)

    OpenAIRE

    Lee, Richard; Sawa, Akira

    2014-01-01

    In this review, we provide a brief summary of several key studies that broaden our understanding of stress and its epigenetic control of the hypothalamic-pituitary-adrenal axis (HPA)-axis function and behavior. Clinical and animal studies suggest a link among exposure to stress, dysregulation of the HPA-axis, and susceptibility to neuropsychiatric illnesses. Recent studies have supported the notion that exposure to glucocorticoids and stress in various forms, duration, and intensity during di...

  11. SU-E-T-371: Validation of Organ Doses Delivered During Craniospinal Irradiation with Helical Tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Andujar, A; Chen, J; Garcia, A; Haas-Kogan, D [University of San Francisco, San Francisco, CA (United States)

    2014-06-01

    Purpose: New techniques have been developed to deliver more conformal treatments to the craniospinal axis. One concern, however, is the widespread low dose delivered and implications for possible late effects. The purpose of this work is for the first time to validate the organ doses calculated by the treatment planning system (TPS), including out-of-field doses for a pediatric craniospinal treatment (CSI). Methods: A CSI plan prescribed to 23.4 Gy and a posterior fossa boost plan to 30.6 Gy (total dose 54.0 Gy) was developed for a pediatric anthropomorphic phantom representing a 13 yearold- child. For the CSI plan, the planning target volumes (PTV) consisted of the brain and spinal cord with 2 mm and 5 mm expansions, respectively. Organs at risk (OAR) were contoured and included in the plan optimization. The plans were delivered on a helical tomotherapy unit. Thermoluminescent dosimeters (TLDs) were used to measure the dose at 54 positions within the PTV and OARs. Results: For the CSI treatment, the mean percent difference between TPS dose calculations and measurements was 5% for the PTV and 10% for the OARs. For the boost, the average was 3% for the PTV. The percent difference for the OARs, which lie outside the field and received a small fraction of the prescription dose, varied from 15% to 200%. However in terms of absolute dose, the average difference between measurement and TPS per treatment Gy was 2 cGy/Gy and 3 mGy/Gy for the CSI and boost plans, respectively. Conclusion: There was good agreement between doses calculated by the TPS and measurements for the CSI treatment. Higher percent differences were observed for out-of-field doses in the boost plan, but absolute dose differences were very small compared to the prescription dose. These findings can help in the estimation of late effects after radiotherapy for pediatric patients.

  12. SI units in radiation protection

    International Nuclear Information System (INIS)

    Herrmann, D.

    1976-10-01

    In the field of radiation protection all hitherto used units for activity, activity concentrations, exposure, absorbed dose, and dose rates have to be replaced by SI units during the next years. For this purpose graphs and conversion tables are given as well as recommendations on unit combinations preferentially to be used. As to the dose equivalent, it is suggested to introduce a new special unit being 100 times greater than the rem, instead of maintaining the rem or using the gray for both absorbed dose and dose equivalent. Measures and time schedule relating to the gradual transition to SI units in measuring techniques, training, and publishing et cetera are explained. (author)

  13. Dose volume assessment of high dose rate 192IR endobronchial implants

    International Nuclear Information System (INIS)

    Cheng, B. Saw; Korb, Leroy J.; Pawlicki, Todd; Wu, Andrew

    1996-01-01

    Purpose: To study the dose distributions of high dose rate (HDR) endobronchial implants using the dose nonuniformity ratio (DNR) and three volumetric irradiation indices. Methods and Materials: Multiple implants were configured by allowing a single HDR 192 Ir source to step through a length of 6 cm along an endobronchial catheter. Dwell times were computed to deliver a dose of 5 Gy to points 1 cm away from the catheter axis. Five sets of source configurations, each with different dwell position spacings from 0.5 to 3.0 cm, were evaluated. Three-dimensional (3D) dose distributions were then generated for each source configuration. Differential and cumulative dose-volume curves were generated to quantify the degree of target volume coverage, dose nonuniformity within the target volume, and irradiation of tissues outside the target volume. Evaluation of the implants were made using the DNR and three volumetric irradiation indices. Results: The observed isodose distributions were not able to satisfy all the dose constraints. The ability to optimally satisfy the dose constraints depended on the choice of dwell position spacing and the specification of the dose constraint points. The DNR and irradiation indices suggest that small dwell position spacing does not result in a more homogeneous dose distribution for the implant. This study supports the existence of a relationship between the dwell position spacing and the distance from the catheter axis to the reference dose or dose constraint points. Better dose homogeneity for an implant can be obtained if the spacing of the dwell positions are about twice the distance from the catheter axis to the reference dose or dose constraint points

  14. Nitric oxide in the stress axis.

    Science.gov (United States)

    López-Figueroa, M O; Day, H E; Akil, H; Watson, S J

    1998-10-01

    In recent years nitric oxide (NO) has emerged as a unique biological messenger. NO is a highly diffusible gas, synthesized from L-arginine by the enzyme nitric oxide synthase (NOS). Three unique subtypes of NOS have been described, each with a specific distribution profile in the brain and periphery. NOS subtype I is present, among other areas, in the hippocampus, hypothalamus, pituitary and adrenal gland. Together these structures form the limbic-hypothalamic-pituitary-adrenal (LHPA) or stress axis, activation of which is one of the defining features of a stress response. Evidence suggests that NO may modulate the release of the stress hormones ACTH and corticosterone, and NOS activity and transcription is increased in the LHPA axis following various stressful stimuli. Furthermore, following activation of the stress axis, glucocorticoids are thought to down-regulate the transcription and activity of NOS via a feedback mechanism. Taken together, current data indicate a role for NO in the regulation of the LHPA axis, although at present this role is not well defined. It has been suggested that NO may act as a cellular communicator in plasticity and development, to facilitate the activation or the release of other neurotransmitters, to mediate immune responses, and/or as a vasodilator in the regulation of blood flow. In the following review we summarize some of the latest insights into the function of NO, with special attention to its relationship with the LHPA axis.

  15. Neutral axis as damage sensitive feature

    International Nuclear Information System (INIS)

    Sigurdardottir, D H; Glisic, B

    2013-01-01

    Structural health monitoring (SHM) is the process of continuously or periodically measuring structural parameters and the transformation of the collected data into information on real structural conditions. The centroid of stiffness is a universal parameter and its position in a cross-section can be evaluated for any load-carrying beam structure as the position of the neutral axis under conveniently chosen loads. Thus, a change in the position of the neutral axis within a cross-section can indicate a change in the position of the centroid of stiffness, i.e., unusual structural behaviors. This paper proposes a novel monitoring method based on deterministic and probabilistic determination of the position of the neutral axis under conveniently chosen conditions. Therefore, the method proposed in this paper is potentially applicable to a large variety of beam-like structures. Data from two existing structures were used to validate the method and assess its performance: Streicker Bridge at Princeton University and the US202/NJ23 highway overpass in Wayne, NJ. The results show that the neutral axis location is varying even when damage is not present. Reasons for this variation are determined and the accuracy in the evaluation assessed. This paper concludes that the position of the neutral axis can be evaluated with sufficient accuracy using static and dynamic strain measurements performed on appropriate time-scales and indicates its potential to be used as a damage sensitive feature. (paper)

  16. Neutral axis as damage sensitive feature

    Science.gov (United States)

    Sigurdardottir, D. H.; Glisic, B.

    2013-07-01

    Structural health monitoring (SHM) is the process of continuously or periodically measuring structural parameters and the transformation of the collected data into information on real structural conditions. The centroid of stiffness is a universal parameter and its position in a cross-section can be evaluated for any load-carrying beam structure as the position of the neutral axis under conveniently chosen loads. Thus, a change in the position of the neutral axis within a cross-section can indicate a change in the position of the centroid of stiffness, i.e., unusual structural behaviors. This paper proposes a novel monitoring method based on deterministic and probabilistic determination of the position of the neutral axis under conveniently chosen conditions. Therefore, the method proposed in this paper is potentially applicable to a large variety of beam-like structures. Data from two existing structures were used to validate the method and assess its performance: Streicker Bridge at Princeton University and the US202/NJ23 highway overpass in Wayne, NJ. The results show that the neutral axis location is varying even when damage is not present. Reasons for this variation are determined and the accuracy in the evaluation assessed. This paper concludes that the position of the neutral axis can be evaluated with sufficient accuracy using static and dynamic strain measurements performed on appropriate time-scales and indicates its potential to be used as a damage sensitive feature.

  17. Aeroelastically coupled blades for vertical axis wind turbines

    Science.gov (United States)

    Paquette, Joshua; Barone, Matthew F.

    2016-02-23

    Various technologies described herein pertain to a vertical axis wind turbine blade configured to rotate about a rotation axis. The vertical axis wind turbine blade includes at least an attachment segment, a rear swept segment, and optionally, a forward swept segment. The attachment segment is contiguous with the forward swept segment, and the forward swept segment is contiguous with the rear swept segment. The attachment segment includes a first portion of a centroid axis, the forward swept segment includes a second portion of the centroid axis, and the rear swept segment includes a third portion of the centroid axis. The second portion of the centroid axis is angularly displaced ahead of the first portion of the centroid axis and the third portion of the centroid axis is angularly displaced behind the first portion of the centroid axis in the direction of rotation about the rotation axis.

  18. Reduction in the volume of water for ingesting orally disintegrating tablets of solifenacin (Vesicare® OD), and the clinical disintegration time of Vesicare® OD after unit-dose packaging.

    Science.gov (United States)

    Uchida, Shinya; Yoshita, Tomohiro; Namiki, Noriyuki

    2013-03-25

    This study aimed to determine the amount of water required for ingesting an orally disintegrating tablet (ODT) of solifenacin (Vesicare(®), VES) and VES conventional tablets (VES-CT). We measured the disintegration time of VES-ODT in the oral cavity (clinical disintegration time) before and after unit-dose packaging. Thirty healthy volunteers participated in this randomized crossover trial. The participants were asked to drink water during the intake placebos of VES and after the disintegration of placebos of VES-ODT in their oral cavity. The amounts of water required for ingesting placebos of VES-CT and of VES-ODT were 42.8±27.0 mL and 20.0±23.7 mL, respectively, which indicated that the amount of water required for ingesting ODTs was significantly lesser than that for ingesting CTs. Furthermore, 5 (16.7%) participants did not require water for ingesting the ODTs. Clinical disintegration time of VES-ODT was 21.4s in 10 healthy volunteers. This clinical disintegration time did not change significantly after unit-dose packaging or subsequent storage for 56 days. This study showed that the amount of water required for ingesting VES-ODT is lower than that for ingesting VES-CT. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  19. Dose distribution over the radiation field and organs of the body during radiotherapy procedures

    International Nuclear Information System (INIS)

    Roy, S.; Begum, M.; Ambia, A.S.M.; Akhter, S.; Banu, H.

    2001-01-01

    Beam profile of the 60 Co teletherapy unit for 10 cm x 10 cm along central axis was measured to study the symmetry of the gamma beam and found that the average dose was 98.44±1.40 mGy. Output dose versus field size was also measured and values were found reasonable. Dose prescription to delivery was measured by placing TLD onto the treatment field for lung and cervix cancer patient which was found to be 39.16±2.98 Gy and 50.48±3.68 Gy respectively which are within 2 % and 0.17 % of the prescribed dose as 40.00 and 50.40 Gy respectively, reveals good agreement with the treatment planning. Six typical types of patients (both male and female) with cancers in lung, larynx, breast, cervix, oesophagus and brain treated with 60 Co teletherapy were particularly considered for dose assessment at different critical organs of interest. It was observed that the doses to the lens of eye with a maximum value of 460.35+78.87 mGy for a larynx cancer patient to a minimum value of 30.80+4.00 mGy of a cervix cancer patient. Doses to the gonad vary with a maximum value of 3810.80+389.76 mGy for a cervix cancer patient to a minimum value of 8.20+1.00 mGy for a brain cancer patient. (author)

  20. Radiation doses during chest examinations using dose modulation techniques in multislice CT scanner

    International Nuclear Information System (INIS)

    Livingstone, Roshan S.; Pradip, Joe; Dinakran, Paul M.; Srikanth, B.

    2010-01-01

    Objectives: To evaluate the radiation dose and image quality using a manual protocol and dose modulation techniques in a 6-slice CT scanner. Materials and Methods: Two hundred and twenty-one patients who underwent contrast-enhanced CT of the chest were included in the study. For the manual protocol settings, constant tube potential (kV) and tube current-time product (mAs) of 140 kV and 120 mAs, respectively, were used. The angular and z-axis dose modulation techniques utilized a constant tube potential of 140 kV; mAs values were automatically selected by the machine. Effective doses were calculated using dose-length product (DLP) values and the image quality was assessed using the signal-to-noise (SNR) ratio values. Mean effective doses using manual protocol for patients of weights 40-60 kg, 61-80 kg, and 81 kg and above were 8.58 mSv, 8.54 mSv, and 9.07 mSv, respectively. Mean effective doses using z-axis dose modulation for patients of weights 40-60 kg, 61-80 kg, and 81 kg and above were 4.95 mSv, 6.87 mSv, and 10.24 mSv, respectively. The SNR at the region of the liver for patients of body weight of 40-60 kg was 5.1 H, 6.2 H, and 8.8 H for manual, angular, and z-axis dose modulation, respectively. Conclusion: Dose reduction of up to 15% was achieved using angular dose modulation and of up to 42% using z-axis dose modulation, with acceptable diagnostic image quality compared to the manual protocol. (author)

  1. Theoretical tool movement required to diamond turn an off-axis paraboloid on axis

    International Nuclear Information System (INIS)

    Thompson, D.C.

    1976-01-01

    Current techniques for manufacturing off-axis paraboloids are both expensive and insufficiently accurate. An alternative method, turning the workpiece about its axis on a diamond-turning machine, is presented, and the equations describing the necessary tool movement are derived. A discussion of a particular case suggests that the proposed technique is feasible

  2. New Urban Vertical Axis Wind Turbine Design

    Directory of Open Access Journals (Sweden)

    Alexandru-Mihai CISMILIANU

    2015-12-01

    Full Text Available This paper develops a different approach for enhancing the performance of Vertical Axis Wind Turbines for the use in the urban or rural environment and remote isolated residential areas. Recently the vertical axis wind turbines (VAWT have become more attractive due to the major advantages of this type of turbines in comparison to the horizontal axis wind turbines. We aim to enhance the overall performance of the VAWT by adding a second set of blades (3 x 2=6 blades following the rules of biplane airplanes. The model has been made to operate at a maximum power in the range of the TSR between 2 to 2.5. The performances of the VAWT were investigated numerically and experimentally and justify the new proposed design.

  3. Surveys of radon levels in homes in the United States: A test of the linear-no-threshold dose-response relationship for radiation carcinogenesis

    International Nuclear Information System (INIS)

    Cohen, B.L.

    1987-01-01

    The University of Pittsburgh Radon Project for large scale measurements of radon concentrations in homes is described. Its principal research is to test the linear-no threshold dose-response relationship for radiation carcinogenesis by determining average radon levels in the 25 U.S. counties (within certain population ranges) with highest and lowest lung cancer rates. The theory predicts that the former should have about 3 times higher average radon levels than the latter, under the assumption that any correlation between exposure to radon and exposure to other causes of lung cancer is weak. The validity of this assumption is tested with data on average radon level vs replies to items on questionnaires; there is little correlation between radon levels in houses and smoking habits, educational attainment, or economic status of the occupants, or with urban vs rural environs which is an indicator of exposure to air pollution

  4. A convolution-superposition dose calculation engine for GPUs

    Energy Technology Data Exchange (ETDEWEB)

    Hissoiny, Sami; Ozell, Benoit; Despres, Philippe [Departement de genie informatique et genie logiciel, Ecole polytechnique de Montreal, 2500 Chemin de Polytechnique, Montreal, Quebec H3T 1J4 (Canada); Departement de radio-oncologie, CRCHUM-Centre hospitalier de l' Universite de Montreal, 1560 rue Sherbrooke Est, Montreal, Quebec H2L 4M1 (Canada)

    2010-03-15

    Purpose: Graphic processing units (GPUs) are increasingly used for scientific applications, where their parallel architecture and unprecedented computing power density can be exploited to accelerate calculations. In this paper, a new GPU implementation of a convolution/superposition (CS) algorithm is presented. Methods: This new GPU implementation has been designed from the ground-up to use the graphics card's strengths and to avoid its weaknesses. The CS GPU algorithm takes into account beam hardening, off-axis softening, kernel tilting, and relies heavily on raytracing through patient imaging data. Implementation details are reported as well as a multi-GPU solution. Results: An overall single-GPU acceleration factor of 908x was achieved when compared to a nonoptimized version of the CS algorithm implemented in PlanUNC in single threaded central processing unit (CPU) mode, resulting in approximatively 2.8 s per beam for a 3D dose computation on a 0.4 cm grid. A comparison to an established commercial system leads to an acceleration factor of approximately 29x or 0.58 versus 16.6 s per beam in single threaded mode. An acceleration factor of 46x has been obtained for the total energy released per mass (TERMA) calculation and a 943x acceleration factor for the CS calculation compared to PlanUNC. Dose distributions also have been obtained for a simple water-lung phantom to verify that the implementation gives accurate results. Conclusions: These results suggest that GPUs are an attractive solution for radiation therapy applications and that careful design, taking the GPU architecture into account, is critical in obtaining significant acceleration factors. These results potentially can have a significant impact on complex dose delivery techniques requiring intensive dose calculations such as intensity-modulated radiation therapy (IMRT) and arc therapy. They also are relevant for adaptive radiation therapy where dose results must be obtained rapidly.

  5. RITA: The reinvented triple axis spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Mason, T.E. [Toronto Univ., ON (Canada). Dept. of Physics; Clausen, K.N.; Aeppli, G.; McMorrow, D.R.; Kjems, J.K. [Risoe National Lab., Roskilde (Denmark)

    1995-11-01

    Risoe National Laboratory was reported to be in the process of developing a new spectrometer design, RITA, based on the triple axis design. The spectrometer will attempt to incorporate more recent innovations such as multilayer supermirrors and microstrip proportional counters into a rethinking of the triple-axis spectrometer. By optimizing the beam optics, using supermirrors and extending the analyser to map regions of (Q, {omega}) space using an array of independently controllable pyrolytic graphite crystals focussed on an area detector, it was hoped that the efficiency of single-crystal inelastic experiments could be increased by as much as a factor of 20. 7 figs., 20 refs.

  6. Equilibrium studies of helical axis stellarators

    International Nuclear Information System (INIS)

    Hender, T.C.; Carreras, B.A.; Garcia, L.; Harris, J.H.; Rome, J.A.; Cantrell, J.L.; Lynch, V.E.

    1984-01-01

    The equilibrium properties of helical axis stellarators are studied with a 3-D equilibrium code and with an average method (2-D). The helical axis ATF is shown to have a toroidally dominated equilibrium shift and good equilibria up to at least 10% peak beta. Low aspect ratio heliacs, with relatively large toroidal shifts, are shown to have low equilibrium beta limits (approx. 5%). Increasing the aspect ratio and number of field periods proportionally is found to improve the equilibrium beta limit. Alternatively, increasing the number of field periods at fixed aspect ratio which raises and lowers the toroidal shift improves the equilibrium beta limit

  7. Dose Distribution of Gamma Irradiators

    International Nuclear Information System (INIS)

    Park, Seung Woo; Shin, Sang Hun; Son, Ki Hong; Lee, Chang Yeol; Kim, Kum Bae; Jung, Hai Jo; Ji, Young Hoon

    2010-01-01

    Gamma irradiator using Cs-137 have been widely utilized to the irradiation of cell, blood, and animal, and the dose measurement and education. The Gamma cell 3000 Elan (Nordion International, Kanata, Ontario, Canada) irradiator was installed in 2003 with Cs-137 and dose rate of 3.2 Gy/min. And the BioBeam 8000 (Gamma-Service Medical GmbH, Leipzig, Germany) irradiator was installed in 2008 with Cs-137 and dose rate of 3.5 Gy/min. Our purpose was to evaluate the practical dosimetric problems associated with inhomogeneous dose distribution within the irradiated volume in open air state using glass dosimeter and Gafchromic EBT film dosimeter for routine Gamma irradiator dosimetry applications at the KIRAMS and the measurements were compared with each other. In addition, an user guideline for useful utilization of the device based on practical dosimetry will be prepared. The measurement results of uniformity of delivered dose within the device showed variation more than 14% between middle point and the lowest position at central axis. Therefore, to maintain dose variation within 10%, the criteria of useful dose distribution, for research radiation effects, the irradiated specimen located at central axis of the container should be placed within 30 mm from top and bottom surface, respectively. In addition, for measurements using the film, the variations of dose distribution were more then 50% for the case of less than 10 second irradiation, mostly within 20% for the case of more than 20 second irradiation, respectively. Therefore, the irradiation experiments using the BioBeam 8000 irradiator are recommended to be used for specimen required at least more than 20 second irradiation time.

  8. Passive dosing of polycyclic aromatic hydrocarbon (PAH) mixtures to terrestrial springtails: Linking mixture toxicity to chemical activities, equilibrium lipid concentrations, and toxic units

    DEFF Research Database (Denmark)

    Schmidt, Stine Nørgaard; Holmstrup, Martin; Smith, Kilian E. C.

    2013-01-01

    treatments, containing the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene, and pyrene. Springtail lethality was then linked to sum chemical activities (∑a), sum equilibrium lipid concentrations (∑Clipid eq.), and sum toxic units (∑TU). In each case, the effects of all 12 mixture treatments...... could be fitted to one sigmoidal exposure-response relationship. The effective lethal chemical activity (La50) of 0.027 was well within the expected range for baseline toxicity of 0.01-0.1. Linking the effects to the lipid-based exposure parameter yielded an effective lethal concentration (LClipid eq...

  9. Modelling simple helically delivered dose distributions

    International Nuclear Information System (INIS)

    Fenwick, John D; Tome, Wolfgang A; Kissick, Michael W; Mackie, T Rock

    2005-01-01

    In a previous paper, we described quality assurance procedures for Hi-Art helical tomotherapy machines. Here, we develop further some ideas discussed briefly in that paper. Simple helically generated dose distributions are modelled, and relationships between these dose distributions and underlying characteristics of Hi-Art treatment systems are elucidated. In particular, we describe the dependence of dose levels along the central axis of a cylinder aligned coaxially with a Hi-Art machine on fan beam width, couch velocity and helical delivery lengths. The impact on these dose levels of angular variations in gantry speed or output per linear accelerator pulse is also explored

  10. New recommendations for dose equivalent

    International Nuclear Information System (INIS)

    Bengtsson, G.

    1985-01-01

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

  11. Radiation dose electrophysiology procedures

    International Nuclear Information System (INIS)

    Hernandez-Armas, J.; Rodriguez, A.; Catalan, A.; Hernandez Armas, O.; Luque Japon, L.; Moral, S.; Barroso, L.; Rfuez-Hdez, R.

    2006-01-01

    The aim of this paper has been to measure and analyse some of the parameters which are directly related with the doses given to patients in two electrophysiology procedures: diagnosis and ablation with radiofrequency. 16 patients were considered in this study. 13 them had an ablation with radiofrequency at the Unit of Electrophysiology at the University Hospital of the Canaries, La Laguna., Tenerife. The results of skin doses, in the ablation cases, were higher than 2 Gy (threshold of some deterministic effects). The average value was 1.1 Gy. The personal doses, measured under the lead apron, for physician and nurses were 4 and 3 micro Sievert. These results emphasised the necessity of radiation protection measures in order to reduce, ad much as possible, the doses to patients. (Author)

  12. Triple-axis spectrometer DruechaL

    International Nuclear Information System (INIS)

    Buehrer, W.; Keller, P.

    1996-01-01

    DruechaL is a triple-axis spectrometer located at a cold guide. The characteristics of guide and instrument allow the use of a broad spectral range of neutrons. The resolution in momentum and energy transfer can be tuned to match the experimental requirements by using either collimators or focusing systems (monochromator, antitrumpet, analyser). (author) figs., tabs., refs

  13. Vortex capturing vertical axis wind turbine

    International Nuclear Information System (INIS)

    Zannetti, L; Gallizio, F; Ottino, G

    2007-01-01

    An analytical-numerical study is presented for an innovative lift vertical axis turbine whose blades are designed with vortex trapping cavities that act as passive flow control devices. The unsteady flow field past one-bladed and two-bladed turbines is described by a combined analytical and numerical method based on conformal mapping and on a blob vortex method

  14. The Trading Axis in Irkutsk Downtown

    Directory of Open Access Journals (Sweden)

    Elena Grigoryeva

    2016-10-01

    Full Text Available The article reveals a linear concentration of the trading function in the historical center of Irkutsk. It features historical prerequisites and continuation of the tradition in the post-Soviet period, given the conversion of plants and factories. The article analyses the current state and prospects of modernization of the trading axis with its transformation into a modern public space.

  15. Triple-axis spectrometer DruechaL

    Energy Technology Data Exchange (ETDEWEB)

    Buehrer, W; Keller, P [Lab. for Neutron Scattering ETH Zurich, Zurich (Switzerland) and Paul Scherrer Institute, Villigen (Switzerland)

    1996-11-01

    DruechaL is a triple-axis spectrometer located at a cold guide. The characteristics of guide and instrument allow the use of a broad spectral range of neutrons. The resolution in momentum and energy transfer can be tuned to match the experimental requirements by using either collimators or focusing systems (monochromator, antitrumpet, analyser). (author) figs., tabs., refs.

  16. Influence of Moisture Content and Compression Axis on Physico-mechanical Properties of Shorea robusta Seeds

    Science.gov (United States)

    Shashikumar, C.; Pradhan, R. C.; Mishra, S.

    2018-02-01

    Shorea robusta (Sal) is mainly harvested and processed for its seed oil, which has diverse application in commercial food and non-food based industries. Before extraction of its oil, seeds undergo into various post-harvest unit operations. Physical and mechanical properties play an important role in the handling and other processing activity. In this study influence of moisture content and compression axis of sal seed on physico-mechanical properties were studied and their application are highlighted. The experiments were conducted at five different moisture levels of 6.38, 10.49, 13.63, 17.64, and 21.95% (d.b) at two different orientations. The first orientation is on major axis (LEN) of the seed, and the other orientation is on intermediate or minor axis (WID), which is right angle to the major axis. It was observed that 68% of sal seeds were of medium size group at initial moisture content of 10.49% (d.b). The mean length and width of sal seed was found to be 26.7 mm and 12.8 mm, respectively. It was found that values of hardness, deformation at hardness, deformation at hardness percentage and energy for rupture were higher in minor axis (WID) as compared to the major axis (LEN). The results provide necessary data that may be useful to engineers, scientists, industries in the design of a suitable post-harvest processing machine.

  17. Design and implementation of five-axis transformation function in CNC system

    Directory of Open Access Journals (Sweden)

    Wang Feng

    2014-04-01

    Full Text Available To implement five-axis functions in CNC system, based on domestic system Lan Tian series, an improved design method for the system software structure is proposed in this paper. The numerical control kernel of CNC system is divided into the task layer and the motion layer. A five-axis transformation unit is integrated into the motion layer. After classifying five-axis machines into different types and analyzing their geometry information, the five-axis kinematic library is designed according to the abstract factory pattern. Furthermore, by taking CA spindle-tilting machine as an example, the forward and the inverse kinematic transformations are deduced. Based on the new software architecture and the five-axis kinematic library, algorithms of RTCP (rotation tool center point control and 3D radius compensation for end-milling are designed and realized. The milling results show that, with five-axis functions based on such software structure, the instructions with respect to the cutter’s position and orientation can be directly carried out in the CNC system.

  18. Influence of Moisture Content and Compression Axis on Physico-mechanical Properties of Shorea robusta Seeds

    Science.gov (United States)

    Shashikumar, C.; Pradhan, R. C.; Mishra, S.

    2018-06-01

    Shorea robusta (Sal) is mainly harvested and processed for its seed oil, which has diverse application in commercial food and non-food based industries. Before extraction of its oil, seeds undergo into various post-harvest unit operations. Physical and mechanical properties play an important role in the handling and other processing activity. In this study influence of moisture content and compression axis of sal seed on physico-mechanical properties were studied and their application are highlighted. The experiments were conducted at five different moisture levels of 6.38, 10.49, 13.63, 17.64, and 21.95% (d.b) at two different orientations. The first orientation is on major axis (LEN) of the seed, and the other orientation is on intermediate or minor axis (WID), which is right angle to the major axis. It was observed that 68% of sal seeds were of medium size group at initial moisture content of 10.49% (d.b). The mean length and width of sal seed was found to be 26.7 mm and 12.8 mm, respectively. It was found that values of hardness, deformation at hardness, deformation at hardness percentage and energy for rupture were higher in minor axis (WID) as compared to the major axis (LEN). The results provide necessary data that may be useful to engineers, scientists, industries in the design of a suitable post-harvest processing machine.

  19. Dose limits

    International Nuclear Information System (INIS)

    Fitoussi, L.

    1987-12-01

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

  20. Kennedy Axis V: Clinimetric properties assessed by mental health nurses.

    Science.gov (United States)

    Faay, Margo D M; van de Sande, Roland; Gooskens, Floor; Hafsteinsdóttir, Thóra B

    2013-10-01

    The Kennedy Axis V is a routine outcome measurement instrument which can assist the assessment of the short-term risk for violence and other adverse patient outcomes. The purpose of this study was to evaluate the interrater reliability and clinical utility of the instrument when used by mental health nurses in daily care of patients with mental illness. This cross-sectional study was conducted in inpatient and outpatient adult psychiatric care units and in one adolescent inpatient unit at a university hospital in the Netherlands. Interrater reliability was measured based on the independent scores of two different nurses for the same patients. The clinical utility of the instrument was evaluated by means of a clinical utility questionnaire. To gain a deeper understanding of rating difficulties at the adolescent unit, additional data were collected in two focus group interviews. The overall results revealed a substantial level of agreement between nurses (intraclass correlation coefficient and Pearson 0.79). Some rating challenges were identified, including difficulties with scoring the instrument and using tailor-made interventions related to the scores. These challenges can be resolved using refined training and implementation strategies. When the Kennedy Axis V is accompanied by a solid implementation strategy in adult mental health care, the instrument can be used for short-term risk assessment and thereby contribute in efforts to reduce violence, suicide, self-harm, severe self-neglect, and enhanced objectivity in clinical decision-making. © 2012 The Authors; International Journal of Mental Health Nursing © 2012 Australian College of Mental Health Nurses Inc.

  1. A review of radiology staff doses and dose monitoring requirements

    International Nuclear Information System (INIS)

    Martin, C. J.

    2009-01-01

    Studies of radiation doses received during X-ray procedures by radiology, cardiology and other clinical staff have been reviewed. Data for effective dose (E), and doses to the eyes, thyroid, hands and legs have been analysed. These data have been supplemented with local measurements to determine the most exposed part of the hand for monitoring purposes. There are ranges of 60-100 in doses to individual tissues reported in the literature for similar procedures at different centres. While ranges in the doses per unit dose-area product (DAP) are between 10 and 25, large variations in dose result from differences in the sensitivity of the X-ray equipment, the type of procedure and the operator technique, but protection factors are important in maintaining dose levels as low as possible. The influence of shielding devices is significant for determining the dose to the eyes and thyroid, and the position of the operator, which depends on the procedure, is the most significant factor determining doses to the hands. A second body dosemeter worn at the level of the collar is recommended for operators with high workloads for use in assessment of effective dose and the dose to the eye. It is proposed that the third quartile values from the distributions of dose per unit DAP identified in the review might be employed in predicting the orders of magnitude of doses to the eye, thyroid and hands, based on interventional operator workloads. Such dose estimates could be employed in risk assessments when reviewing protection and monitoring requirements. A dosemeter worn on the little finger of the hand nearest to the X-ray tube is recommended for monitoring the hand. (authors)

  2. Development of a multi-electrode extrapolation chamber as a prototype of a primary standard for the realization of the unit of the absorbed dose to water for beta brachytherapy sources

    CERN Document Server

    Bambynek, M

    2002-01-01

    The prototype of a primary standard has been developed, built and tested, which enables the realization of the unit of the absorbed dose to water for beta brachytherapy sources. In the course of the development of the prototype, the recommendations of the American Association of Physicists in Medicine (AAPM) Task Group 60 (TG60) and the Deutsche Gesellschaft fuer Medizinische Physik (DGMP) Arbeitskreis 18 (AK18) were taken into account. The prototype is based on a new multi-electrode extrapolation chamber (MEC) which meets, in particular, the requirements on high spatial resolution and small uncertainty. The central part of the MEC is a segmented collecting electrode which was manufactured in the clean room center of PTB by means of electron beam lithography on a wafer. A precise displacement device consisting of three piezoelectric macrotranslators has been incorporated to move the wafer collecting electrode against the entrance window. For adjustment of the wafer collecting electrode parallel to the entranc...

  3. Surface applicators for high dose rate brachytherapy in AIDS-related kaposi's sarcoma

    International Nuclear Information System (INIS)

    Evans, Michael D.C.; Yassa, Mariam; Podgorsak, Ervin B.; Roman, Ted N.; Schreiner, L. John; Souhami, Luis

    1997-01-01

    Purpose: The development of commercially available surface applicators using high dose rate remote afterloading devices has enabled radiotherapy centers to treat selected superficial lesions using a remote afterloading brachytherapy unit. The dosimetric parameters of these applicators, the clinical implementation of this technique, and a review of the initial patient treatment regimes are presented. Methods and Materials: A set of six fixed-diameter (1, 2, and 3 cm), tungsten/steel surface applicators is available for use with a single stepping-source (Ir-192, 370 GBq) high dose rate afterloader. The source can be positioned either in a parallel or perpendicular orientation to the treatment plane at the center of a conical aperture that sits at an SSD of approximately 15 mm and is used with a 1-mm thick removable plastic cap. The surface dose rates, percent depth dose, and off-axis ratios were measured. A custom-built, ceiling-mounted immobilization device secures the applicator on the surface of the patient's lesion during treatment. Results: Between November 1994, and September 1996, 16 AIDS-related Kaposi's sarcoma patients having a total of 120 lesions have been treated with palliative intent. Treatment sites were distributed between the head and neck, extremity, and torso. Doses ranged from 8 to 20 Gy, with a median dose of 10 Gy delivered in a single fraction. Treatments were well tolerated with minimal skin reaction, except for patients with lesions treated to 20 Gy who developed moderate/severe desquamation. Conclusion: Radiotherapy centers equipped with a high dose rate remote afterloading unit may treat small selected surface lesions with commercially available surface applicators. These surface applicators must be used with a protective cap to eliminate electron contamination. The optimal surface dose appears to be either 10 or 15 Gy depending upon the height of the lesion

  4. Comparison of experimental and theoretical depth doses in the ICRU sphere using 137Cs

    International Nuclear Information System (INIS)

    Williams, G.; Jankowski, J.; Swanson, W.P.; Drexler, G.

    1985-01-01

    To confirm the theoretical model used at the Gesellschaft fuer Strahlen- and Umweltforschung, mbH (GSF) to calculate photon depth-dose distributions in the International Commission on Radiological Units and Measurements (ICRU) sphere, an experiment was performed using 137 Cs (662 keV). Measurements were made for a unidirectional parallel beam and for planar-isotropic irradiation. The theory predicts that, for photons of this energy, the maximum dose occurs at the equator of the sphere, when a broad unidirectional parallel beam is incident along the polar (central) axis. The energy of photons from 137 Cs is well suited for a test of this sort because the ratio of equatorial maximum to central-axis maximum appears to have a broad maximum itself at about this energy. In the theory, charged particle equilibrium (CPE) is assumed and the kerma approximation is applied. It is possible that the degree to which CPE is attained affects the outcome, especially at the equator, but if sufficient charge-build-up occurs in the air at the sphere surface then the kerma approximation is acceptable and the calculated distributions should be closely representative of the absorbed-dose distributions

  5. SU-F-SPS-01: Accuracy of the Small Field Dosimetry Using Acuros XB and AAA Dose Calculation Algorithms of Eclipse Treatment Planning System Within and Beyond Heterogeneous Media for Trubeam 2.0 Unit

    International Nuclear Information System (INIS)

    Codel, G; Serin, E; Pacaci, P; Sanli, E; Cebe, M; Mabhouti, H; Doyuran, M; Kucukmorkoc, E; Kucuk, N; Altinok, A; Canoglu, D; Acar, H; Caglar Ozkok, H

    2016-01-01

    Purpose: In this study, the comparison of dosimetric accuracy of Acuros XB and AAA algorithms were investigated for small radiation fields incident on homogeneous and heterogeneous geometries Methods: Small open fields of Truebeam 2.0 unit (1×1, 2×2, 3×3, 4×4 fields) were used for this study. The fields were incident on homogeneous phantom and in house phantom containing lung, air, and bone inhomogeneities. Using the same film batch, the net OD to dose calibration curve was obtaine dusing Trubeam 2.0 for 6 MV, 6 FFF, 10 MV, 10 FFF, 15 MV energies by delivering 0- 800 cGy. Films were scanned 48 hours after irradiation using an Epson 1000XL flatbed scanner. The dosimetric accuracy of Acuros XB and AAA algorithms in the presence of the inhomogeneities was compared against EBT3 film dosimetry Results: Open field tests in a homogeneous phantom showed good agreement betweent wo algorithms and measurement. For Acuros XB, minimum gamma analysis passin grates between measured and calculated dose distributions were 99.3% and 98.1% for homogeneousand inhomogeneous fields in thecase of lung and bone respectively. For AAA, minimum gamma analysis passingrates were 99.1% and 96.5% for homogeneous and inhomogeneous fields respectively for all used energies and field sizes.In the case of the air heterogeneity, the differences were larger for both calculations algorithms. Over all, when compared to measurement, theAcuros XB had beter agreement than AAA. Conclusion: The Acuros XB calculation algorithm in the TPS is an improvemen tover theexisting AAA algorithm. Dose discrepancies were observed for in the presence of air inhomogeneities.

  6. SU-F-SPS-01: Accuracy of the Small Field Dosimetry Using Acuros XB and AAA Dose Calculation Algorithms of Eclipse Treatment Planning System Within and Beyond Heterogeneous Media for Trubeam 2.0 Unit

    Energy Technology Data Exchange (ETDEWEB)

    Codel, G; Serin, E; Pacaci, P; Sanli, E; Cebe, M; Mabhouti, H; Doyuran, M; Kucukmorkoc, E; Kucuk, N; Altinok, A; Canoglu, D; Acar, H; Caglar Ozkok, H [Medipol University, Istanbul, Istanbul (Turkey)

    2016-06-15

    Purpose: In this study, the comparison of dosimetric accuracy of Acuros XB and AAA algorithms were investigated for small radiation fields incident on homogeneous and heterogeneous geometries Methods: Small open fields of Truebeam 2.0 unit (1×1, 2×2, 3×3, 4×4 fields) were used for this study. The fields were incident on homogeneous phantom and in house phantom containing lung, air, and bone inhomogeneities. Using the same film batch, the net OD to dose calibration curve was obtaine dusing Trubeam 2.0 for 6 MV, 6 FFF, 10 MV, 10 FFF, 15 MV energies by delivering 0- 800 cGy. Films were scanned 48 hours after irradiation using an Epson 1000XL flatbed scanner. The dosimetric accuracy of Acuros XB and AAA algorithms in the presence of the inhomogeneities was compared against EBT3 film dosimetry Results: Open field tests in a homogeneous phantom showed good agreement betweent wo algorithms and measurement. For Acuros XB, minimum gamma analysis passin grates between measured and calculated dose distributions were 99.3% and 98.1% for homogeneousand inhomogeneous fields in thecase of lung and bone respectively. For AAA, minimum gamma analysis passingrates were 99.1% and 96.5% for homogeneous and inhomogeneous fields respectively for all used energies and field sizes.In the case of the air heterogeneity, the differences were larger for both calculations algorithms. Over all, when compared to measurement, theAcuros XB had beter agreement than AAA. Conclusion: The Acuros XB calculation algorithm in the TPS is an improvemen tover theexisting AAA algorithm. Dose discrepancies were observed for in the presence of air inhomogeneities.

  7. Mechanical strainer unit

    International Nuclear Information System (INIS)

    Kraeling, J.B.; Netkowicz, R.J.; Schnall, I.H.

    1983-01-01

    The mechanical strainer unit is connected to a flanged conduit which originates in and extends out of a suppression chamber in a nuclear reactor. The strainer includes a plurality of centrally apertured plates positioned along a common central axis and in parallel and spaced relationship. The plates have a plurality of bores radially spaced about the central axis. Spacer means such as washers are positioned between adjacent plates to maintain the plates is spaced relationship and form communicating passages of a predetermined size to the central apertures. Connecting means such as bolts or studs extend through the aligned bores to maintain the unit in assembled relationship and secure the unit to the pipe. By employing perforated plates and blocking off certain of the communicating passages, a dual straining effect can be achieved

  8. Controllable dose

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  9. Resolution of a triple axis spectrometer

    DEFF Research Database (Denmark)

    Nielsen, Mourits; Bjerrum Møller, Hans

    1969-01-01

    A new method for obtaining the resolution function for a triple-axis neutron spectrometer is described, involving a combination of direct measurement and analytical calculation. All factors which contribute to the finite resolution of the instrument may be taken into account, and Gaussian...... or experimentally determined probability distributions may be used. The application to the study of the dispersion relation for excitations in a crystal is outlined...

  10. Interplay between tilted and principal axis rotation

    International Nuclear Information System (INIS)

    Datta, Pradip; Roy, Santosh; Chattopadhyay, S.

    2014-01-01

    At IUAC-INGA, our group has studied four neutron rich nuclei of mass-110 region, namely 109,110 Ag and 108,110 Cd. These nuclei provide the unique platform to study the interplay between Tilted and Principal axis rotation since these are moderately deformed and at the same time, shears structures are present at higher spins. The salient features of the high spin behaviors of these nuclei will be discussed which are the signatures of this interplay

  11. Interplay between tilted and principal axis rotation

    Energy Technology Data Exchange (ETDEWEB)

    Datta, Pradip [Ananda Mohan College, 102/1 Raja Rammohan Sarani, Kolkata 700 009 (India); Roy, Santosh; Chattopadhyay, S. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700 064 (India)

    2014-08-14

    At IUAC-INGA, our group has studied four neutron rich nuclei of mass-110 region, namely {sup 109,110}Ag and {sup 108,110}Cd. These nuclei provide the unique platform to study the interplay between Tilted and Principal axis rotation since these are moderately deformed and at the same time, shears structures are present at higher spins. The salient features of the high spin behaviors of these nuclei will be discussed which are the signatures of this interplay.

  12. Dose optimization of intra-operative high dose rate interstitial brachytherapy implants for soft tissue sarcoma

    Directory of Open Access Journals (Sweden)

    Jamema Swamidas

    2009-01-01

    Full Text Available Objective : A three dimensional (3D image-based dosimetric study to quantitatively compare geometric vs. dose-point optimization in combination with graphical optimization for interstitial brachytherapy of soft tissue sarcoma (STS. Materials and Methods : Fifteen consecutive STS patients, treated with intra-operative, interstitial Brachytherapy, were enrolled in this dosimetric study. Treatment plans were generated using dose points situated at the "central plane between the catheters", "between the catheters throughout the implanted volume", at "distances perpendicular to the implant axis" and "on the surface of the target volume" Geometrically optimized plans had dose points defined between the catheters, while dose-point optimized plans had dose points defined at a plane perpendicular to the implant axis and on the target surface. Each plan was graphically optimized and compared using dose volume indices. Results : Target coverage was suboptimal with coverage index (CI = 0.67 when dose points were defined at the central plane while it was superior when the dose points were defined at the target surface (CI=0.93. The coverage of graphically optimized plans (GrO was similar to non-GrO with dose points defined on surface or perpendicular to the implant axis. A similar pattern was noticed with conformity index (0.61 vs. 0.82. GrO were more conformal and less homogeneous compared to non-GrO. Sum index was superior for dose points defined on the surface of the target and relatively inferior for plans with dose points at other locations (1.35 vs. 1.27. Conclusions : Optimization with dose points defined away from the implant plane and on target results in superior target coverage with optimal values of other indices. GrO offer better target coverage for implants with non-uniform geometry and target volume.

  13. The SFD - 80 M high precision double axis facing lathe

    International Nuclear Information System (INIS)

    Bran, T.; Dragomir, I.; Rusu, I.; Stanciu, S.; Niculceanu, F.; Nica, O.; Popescu, M.; Bailescu, V.; Burcea, Gh.; Turcanu, V.

    2001-01-01

    A high precision double axis facing lathe was designed for machining the 'final end-cup' by exterior conical lathing. The lathe is semi-automatic and includes two independent identical units. The general constructive, dimensional and functional characteristics are presented as well as the specific power consumptions. As compared to other machines able to perform the same operations this machine presents the following novel aspects: - it is dedicated from the design stage to the workpiece to be machined; - the splinting speed is quasi-constant all along the processing span (irrespective of the cutting diameter at which the tool is fixed, in its trajectory generating the exterior cone). At 100% and 80% nominal power values the yield is 240 workpiece/hour and 192 workpiece/hour, respectively

  14. Dose planning and dose delivery in radiation therapy

    International Nuclear Information System (INIS)

    Knoeoes, T.

    1991-01-01

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

  15. Performance of a direct detection camera for off-axis electron holography

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Shery L.Y., E-mail: shery.chang@asu.edu [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, and Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); LeRoy Eyring Center for Solid State Science, Arizona State University, Tempe, AZ 85287 (United States); Dwyer, Christian [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, and Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Department of Physics, Arizona State University, Tempe, AZ 85287 (United States); Barthel, Juri; Boothroyd, Chris B.; Dunin-Borkowski, Rafal E. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, and Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany)

    2016-02-15

    The performance of a direct detection camera (DDC) is evaluated in the context of off-axis electron holographic experiments in a transmission electron microscope. Its performance is also compared directly with that of a conventional charge-coupled device (CCD) camera. The DDC evaluated here can be operated either by the detection of individual electron events (counting mode) or by the effective integration of many such events during a given exposure time (linear mode). It is demonstrated that the improved modulation transfer functions and detective quantum efficiencies of both modes of the DDC give rise to significant benefits over the conventional CCD cameras, specifically, a significant improvement in the visibility of the holographic fringes and a reduction of the statistical error in the phase of the reconstructed electron wave function. The DDC's linear mode, which can handle higher dose rates, allows optimisation of the dose rate to achieve the best phase resolution for a wide variety of experimental conditions. For suitable conditions, the counting mode can potentially utilise a significantly lower dose to achieve a phase resolution that is comparable to that achieved using the linear mode. The use of multiple holograms and correlation techniques to increase the total dose in counting mode is also demonstrated. - Highlights: • Performance of a direct detection camera for off-axis electron holography has been evaluated. • Better holographic fringe visibility and phase resolution are achieved using DDC. • Both counting and linear modes offered by DDC are advantageous for different dose regimes.

  16. Performance of a direct detection camera for off-axis electron holography

    International Nuclear Information System (INIS)

    Chang, Shery L.Y.; Dwyer, Christian; Barthel, Juri; Boothroyd, Chris B.; Dunin-Borkowski, Rafal E.

    2016-01-01

    The performance of a direct detection camera (DDC) is evaluated in the context of off-axis electron holographic experiments in a transmission electron microscope. Its performance is also compared directly with that of a conventional charge-coupled device (CCD) camera. The DDC evaluated here can be operated either by the detection of individual electron events (counting mode) or by the effective integration of many such events during a given exposure time (linear mode). It is demonstrated that the improved modulation transfer functions and detective quantum efficiencies of both modes of the DDC give rise to significant benefits over the conventional CCD cameras, specifically, a significant improvement in the visibility of the holographic fringes and a reduction of the statistical error in the phase of the reconstructed electron wave function. The DDC's linear mode, which can handle higher dose rates, allows optimisation of the dose rate to achieve the best phase resolution for a wide variety of experimental conditions. For suitable conditions, the counting mode can potentially utilise a significantly lower dose to achieve a phase resolution that is comparable to that achieved using the linear mode. The use of multiple holograms and correlation techniques to increase the total dose in counting mode is also demonstrated. - Highlights: • Performance of a direct detection camera for off-axis electron holography has been evaluated. • Better holographic fringe visibility and phase resolution are achieved using DDC. • Both counting and linear modes offered by DDC are advantageous for different dose regimes.

  17. Tank Z-361 dose rate calculations

    International Nuclear Information System (INIS)

    Richard, R.F.

    1998-01-01

    Neutron and gamma ray dose rates were calculated above and around the 6-inch riser of tank Z-361 located at the Plutonium Finishing Plant. Dose rates were also determined off of one side of the tank. The largest dose rate 0.029 mrem/h was a gamma ray dose and occurred 76.2 cm (30 in.) directly above the open riser. All other dose rates were negligible. The ANSI/ANS 1991 flux to dose conversion factor for neutrons and photons were used in this analysis. Dose rates are reported in units of mrem/h with the calculated uncertainty shown within the parentheses

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

    Science.gov (United States)

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

    2011-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-10-01

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

  20. Developing Predictive Approaches to Characterize Adaptive Responses of the Reproductive Endocrine Axis to Aromatase Inhibition: Computational Modeling

    Science.gov (United States)

    Exposure to endocrine disrupting chemicals can affect reproduction and development in both humans and wildlife. We developed a mechanistic mathematical model of the hypothalamic-pituitary-gonadal (HPG) axis in female fathead minnows to predict dose-response and time-course (DRTC)...

  1. Adaptive Response in Female Fathead Minnows Exposed to an Aromatase Inhibitor: Computational Modeling of the Hypothalamic-Pituitary-Gonadal Axis

    Science.gov (United States)

    Exposure to endocrine disrupting chemicals can affect reproduction and development in both humans and wildlife. We are developing a mechanistic computational model of the hypothalamic-pituitary-gonadal (HPG) axis in female fathead minnows to predict dose-response and time-course ...

  2. Predicting Adaptive Response to Fadrozole Exposure: Computational Model of the Fathead Minnow Hypothalamic-Pituitary-Gonadal Axis

    Science.gov (United States)

    Exposure to endocrine disrupting chemicals can affect reproduction and development in both humans and wildlife. We are developing a mechanistic mathematical model of the hypothalamic-pituitary-gonadal (HPG) axis in female fathead minnows to predict dose-response and time-course (...

  3. Autotaxin-lysophosphatidic acid axis is a novel molecular target for lowering intraocular pressure.

    Directory of Open Access Journals (Sweden)

    Padma Iyer

    Full Text Available Primary open-angle glaucoma is the second leading cause of blindness in the United States and is commonly associated with elevated intraocular pressure (IOP resulting from diminished aqueous humor (AH drainage through the trabecular pathway. Developing effective therapies for increased IOP in glaucoma patients requires identification and characterization of molecular mechanisms that regulate IOP and AH outflow. This study describes the identification and role of autotaxin (ATX, a secretory protein and a major source for extracellular lysophosphatidic acid (LPA, in regulation of IOP in a rabbit model. Quantitative proteomics analysis identified ATX as an abundant protein in both human AH derived from non-glaucoma subjects and in AH from different animal species. The lysophospholipase D (LysoPLD activity of ATX was found to be significantly elevated (by ∼1.8 fold; n=20 in AH derived from human primary open angle glaucoma patients as compared to AH derived from age-matched cataract control patients. Immunoblotting analysis of conditioned media derived from primary cultures of human trabecular meshwork (HTM cells has confirmed secretion of ATX and the ability of cyclic mechanical stretch of TM cells to increase the levels of secreted ATX. Topical application of a small molecular chemical inhibitor of ATX (S32826, which inhibited AH LysoPLD activity in vitro (by >90%, led to a dose-dependent and significant decrease of IOP in Dutch-Belted rabbits. Single intracameral injection of S32826 (∼2 µM led to significant reduction of IOP in rabbits, with the ocular hypotensive response lasting for more than 48 hrs. Suppression of ATX expression in HTM cells using small-interfering RNA (siRNA caused a decrease in actin stress fibers and myosin light chain phosphorylation. Collectively, these observations indicate that the ATX-LPA axis represents a potential therapeutic target for lowering IOP in glaucoma patients.

  4. Reassessment and suspension of the nuclear power plant design requirement of the constraint of collective dose per unit of practice. (Requirement 6 (b), Standard AR 3.1.2)

    International Nuclear Information System (INIS)

    Amado, Valeria A.; Canoba, Analia C.; Curti, Adriana R.; Biaggio, Alfredo L.

    2009-01-01

    By the middle of 2005, the Nuclear Regulatory Authority (ARN) decided to re-assess the basis of a design requirement applicable to the limitation of nuclear power reactor radioactive discharges. Such requirement, aimed at restricting the discharge of globally dispersed long-lived radionuclides, was in force in Argentina since 1979 and was expressed as a limitation of the collective dose commitment per unit of electrical energy generated. The practical result of such regulatory action was the need to retain C-14 in the Atucha II power reactor under construction as well as in future heavy water reactors to be built in the country, and, later on, to manage it as to assure its isolation from the biosphere during an appropriate period of time. For the above-mentioned reassessment, an ad hoc task group was created and an internal report was presented to the Board of Directors by the middle of 2007. Because of such report the ARN decided to suspend the application of the requirement (i.e. it is not more mandatory, even for Atucha II). The present work presents the main aspects of that report. In particular, it explains the basis of the design requirement and the most important assumptions that triggered it. The differences between the assumptions made at that time and the reality of nuclear power generation at the beginning of the 21st Century, as well as their implications in relation to the requirement are described, including the Suess effect and its impact in the total dose due to C-14. Finally, after explaining in detail the facts that made no longer reasonable to keep in force the above mentioned requirement, the work presents the conclusions that lead the ARN to the suspension of this requirement. (author) [es

  5. Theoretical tool movement required to diamond turn an off-axis paraboloid on axis

    International Nuclear Information System (INIS)

    Thompson, D.C.

    1975-01-01

    High-quality, off-axis parabolic reflectors, required by the CTR and laser-fusion programs at Lawrence Livermore Laboratory (LLL) and other ERDA laboratories, are currently manufactured by hand. There are several drawbacks to this method, including lead times of up to a year, costs in excess of dollars 75,000 for a small reflector, and unsatisfactory limits to the tolerances obtainable. This situation has led to a search for cheaper and more accurate methods of manufacturing off-axis paraboloids. An alternative method, turning the workpiece about its axis on a diamond-turning machine, is presented, and the equations describing the necessary tool movement are derived. A discussion of a particular case suggests that the proposed technique is feasible

  6. The Triple Axis and SPINS Spectrometers.

    Science.gov (United States)

    Trevino, S F

    1993-01-01

    In this paper are described the triple axis and spin polarized inelastic neutron scattering (SPINS) spectrometers which are installed at the NIST Cold Neutron Research Facility (CNRF). The general principle of operation of these two instruments is described in sufficient detail to allow the reader to make an informed decision as to their usefulness for his needs. However, it is the intention of the staff at the CNRF to provide the expert resources for their efficient use in any given situation. Thus, this work is not intended as a user manual but rather as a guide into the range of applicability of the two instruments.

  7. Equilibrium calculations for helical axis stellarators

    International Nuclear Information System (INIS)

    Hender, T.C.; Carreras, B.A.

    1984-04-01

    An average method based on a vacuum flux coordinate system is presented. This average method permits the study of helical axis stellarators with toroidally dominated shifts. An ordering is introduced, and to lowest order the toroidally averaged equilibrium equations are reduced to a Grad-Shafranov equation. Also, to lowest order, a Poisson-type equation is obtained for the toroidally varying corrections to the equilibium. By including these corrections, systems that are toroidally dominated, but with significant helical distortion to the equilibrium, may be studied. Numerical solutions of the average method equations are shown to agree well with three-dimensional calculations

  8. Three-axis asymmetric radiation detector system

    Science.gov (United States)

    Martini, Mario Pierangelo; Gedcke, Dale A.; Raudorf, Thomas W.; Sangsingkeow, Pat

    2000-01-01

    A three-axis radiation detection system whose inner and outer electrodes are shaped and positioned so that the shortest path between any point on the inner electrode and the outer electrode is a different length whereby the rise time of a pulse derived from a detected radiation event can uniquely define the azimuthal and radial position of that event, and the outer electrode is divided into a plurality of segments in the longitudinal axial direction for locating the axial location of a radiation detection event occurring in the diode.

  9. Prediction of midline dose from entrance ad exit dose using OSLD measurements for total irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chang Heon; Park, Jong Min; Park, So Yeon; Chun, Min Soo; Han, Ji Hye; Cho, Jin Dong; Kim, Jung In [Dept. of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2017-06-15

    This study aims to predict the midline dose based on the entrance and exit doses from optically stimulated luminescence detector (OSLD) measurements for total body irradiation (TBI). For TBI treatment, beam data sets were measured for 6 MV and 15 MV beams. To evaluate the tissue lateral effect of various thicknesses, the midline dose and peak dose were measured using a solid water phantom (SWP) and ion chamber. The entrance and exit doses were measured using OSLDs. OSLDs were attached onto the central beam axis at the entrance and exit surfaces of the phantom. The predicted midline dose was evaluated as the sum of the entrance and exit doses by OSLD measurement. The ratio of the entrance dose to the exit dose was evaluated at various thicknesses. The ratio of the peak dose to the midline dose was 1.12 for a 30 cm thick SWP at both energies. When the patient thickness is greater than 30 cm, the 15 MV should be used to ensure dose homogeneity. The ratio of the entrance dose to the exit dose was less than 1.0 for thicknesses of less than 30 cm and 40 cm at 6 MV and 15 MV, respectively. Therefore, the predicted midline dose can be underestimated for thinner body. At 15 MV, the ratios were approximately 1.06 for a thickness of 50 cm. In cases where adult patients are treated with the 15 MV photon beam, it is possible for the predicted midline dose to be overestimated for parts of the body with a thickness of 50 cm or greater. The predicted midline dose and OSLD-measured midline dose depend on the phantom thickness. For in-vivo dosimetry of TBI, the measurement dose should be corrected in order to accurately predict the midline dose.

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

    International Nuclear Information System (INIS)

    Ogata, Hiromitsu; Magae, Junji

    2008-01-01

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

  11. Evaluation of the risk of perchlorate exposure in a population of late-gestation pregnant women in the United States: Application of probabilistic biologically-based dose response modeling

    International Nuclear Information System (INIS)

    Lumen, A; George, N I

    2017-01-01

    The risk of ubiquitous perchlorate exposure and the dose-response on thyroid hormone levels in pregnant women in the United States (U.S.) have yet to be characterized. In the current work, we integrated a previously developed perchlorate submodel into a recently developed population-based pregnancy model to predict reductions in maternal serum free thyroxine (fT4) levels for late-gestation pregnant women in the U.S. Our findings indicated no significant difference in geometric mean estimates of fT4 when perchlorate exposure from food only was compared to no perchlorate exposure. The reduction in maternal fT4 levels reached statistical significance when an added contribution from drinking water (i.e., 15 μg/L, 20 μg/L, or 24.5 μg/L) was assumed in addition to the 90th percentile of food intake for pregnant women (0.198 μg/kg/day). We determined that a daily intake of 0.45 to 0.50 μg/kg/day of perchlorate was necessary to produce results that were significantly different than those obtained from no perchlorate exposure. Adjusting for this food intake dose, the relative source contribution of perchlorate from drinking water (or other non-dietary sources) was estimated to range from 0.25–0.3 μg/kg/day. Assuming a drinking water intake rate of 0.033 L/kg/day, the drinking water concentration allowance for perchlorate equates to 7.6–9.2 μg/L. In summary, we have demonstrated the utility of a probabilistic biologically-based dose-response model for perchlorate risk assessment in a sensitive life-stage at a population level; however, there is a need for continued monitoring in regions of the U.S. where perchlorate exposure may be higher. - Highlights: • Probabilistic risk assessment for perchlorate in U.S. pregnant women was conducted. • No significant change in maternal fT4 predicted due to perchlorate from food alone. • Drinking water concentration allowance for perchlorate estimated as 7.6–9.2 μg/L

  12. Evaluation of the risk of perchlorate exposure in a population of late-gestation pregnant women in the United States: Application of probabilistic biologically-based dose response modeling

    Energy Technology Data Exchange (ETDEWEB)

    Lumen, A, E-mail: Annie.Lumen@fda.hhs.gov [Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd, HFT-110, Jefferson, AR 72079 (United States); George, N I, E-mail: Nysia.George@fda.hhs.gov [Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd, HFT-20, Jefferson, AR 72079 (United States)

    2017-05-01

    The risk of ubiquitous perchlorate exposure and the dose-response on thyroid hormone levels in pregnant women in the United States (U.S.) have yet to be characterized. In the current work, we integrated a previously developed perchlorate submodel into a recently developed population-based pregnancy model to predict reductions in maternal serum free thyroxine (fT4) levels for late-gestation pregnant women in the U.S. Our findings indicated no significant difference in geometric mean estimates of fT4 when perchlorate exposure from food only was compared to no perchlorate exposure. The reduction in maternal fT4 levels reached statistical significance when an added contribution from drinking water (i.e., 15 μg/L, 20 μg/L, or 24.5 μg/L) was assumed in addition to the 90th percentile of food intake for pregnant women (0.198 μg/kg/day). We determined that a daily intake of 0.45 to 0.50 μg/kg/day of perchlorate was necessary to produce results that were significantly different than those obtained from no perchlorate exposure. Adjusting for this food intake dose, the relative source contribution of perchlorate from drinking water (or other non-dietary sources) was estimated to range from 0.25–0.3 μg/kg/day. Assuming a drinking water intake rate of 0.033 L/kg/day, the drinking water concentration allowance for perchlorate equates to 7.6–9.2 μg/L. In summary, we have demonstrated the utility of a probabilistic biologically-based dose-response model for perchlorate risk assessment in a sensitive life-stage at a population level; however, there is a need for continued monitoring in regions of the U.S. where perchlorate exposure may be higher. - Highlights: • Probabilistic risk assessment for perchlorate in U.S. pregnant women was conducted. • No significant change in maternal fT4 predicted due to perchlorate from food alone. • Drinking water concentration allowance for perchlorate estimated as 7.6–9.2 μg/L.

  13. Peripheral dose outside applicators in electron beams

    International Nuclear Information System (INIS)

    Chow, James C L; Grigorov, Grigor N

    2006-01-01

    The peripheral dose outside the applicators in electron beams was studied using a Varian 21 EX linear accelerator. To measure the peripheral dose profiles and point doses for the applicator, a solid water phantom was used with calibrated Kodak TL films. Peak dose spot was observed in the 4 MeV beam outside the applicator. The peripheral dose peak was very small in the 6 MeV beam and was ignorable at higher energies. Using the 10 x 10 cm 2 cutout and applicator, the dose peak for the 4 MeV beam was about 12 cm away from the field central beam axis (CAX) and the peripheral dose profiles did not change with depths measured at 0.2, 0.5 and 1 cm. The peripheral doses and profiles were further measured by varying the angle of obliquity, cutout and applicator size for the 4 MeV beam. The local peak dose was increased with about 3% per degree angle of obliquity, and was about 1% of the prescribed dose (angle of obliquity equals zero) at 1 cm depth in the phantom using the 10 x 10 cm 2 cutout and applicator. The peak dose position was also shifted 7 mm towards the CAX when the angle of obliquity was increased from 0 to 15 deg. (note)

  14. Dose and dose rate monitor

    International Nuclear Information System (INIS)

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

    1984-10-01

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

  15. Sample Based Unit Liter Dose Estimates

    International Nuclear Information System (INIS)

    JENSEN, L.

    1999-01-01

    The Tank Waste Characterization Program has taken many core samples, grab samples, and auger samples from the single-shell and double-shell tanks during the past 10 years. Consequently, the amount of sample data available has increased, both in terms of quantity of sample results and the number of tanks characterized. More and better data is available than when the current radiological and toxicological source terms used in the Basis for Interim Operation (BIO) (FDH 1999) and the Final Safety Analysis Report (FSAR) (FDH 1999) were developed. The Nuclear Safety and Licensing (NS and L) organization wants to use the new data to upgrade the radiological and toxicological source terms used in the BIO and FSAR. The NS and L organization requested assistance in developing a statistically based process for developing the source terms. This report describes the statistical techniques used and the assumptions made to support the development of a new radiological source term for liquid and solid wastes stored in single-shell and double-shell tanks

  16. Extracellular matrix dynamics during vertebrate axis formation.

    Science.gov (United States)

    Czirók, András; Rongish, Brenda J; Little, Charles D

    2004-04-01

    The first evidence for the dynamics of in vivo extracellular matrix (ECM) pattern formation during embryogenesis is presented below. Fibrillin 2 filaments were tracked for 12 h throughout the avian intraembryonic mesoderm using automated light microscopy and algorithms of our design. The data show that these ECM filaments have a reproducible morphogenic destiny that is characterized by directed transport. Fibrillin 2 particles initially deposited in the segmental plate mesoderm are translocated along an unexpected trajectory where they eventually polymerize into an intricate scaffold of cables parallel to the anterior-posterior axis. The cables coalesce near the midline before the appearance of the next-formed somite. Moreover, the ECM filaments define global tissue movements with high precision because the filaments act as passive motion tracers. Quantification of individual and collective filament "behaviors" establish fate maps, trajectories, and velocities. These data reveal a caudally propagating traveling wave pattern in the morphogenetic movements of early axis formation. We conjecture that within vertebrate embryos, long-range mechanical tension fields are coupled to both large-scale patterning and local organization of the ECM. Thus, physical forces or stress fields are essential requirements for executing an emergent developmental pattern-in this case, paraxial fibrillin cable assembly.

  17. VERITAS: Versatile Triple-Axis Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Il

    2006-04-15

    Korea Atomic Energy Research Institute is planning to build a cold neutron triple-axis spectrometer at HANARO, the 30 MW research reactor. The spectrometer is expected to be completed in 2008 with the following configuration from the upstream to the downstream. Guide Supermirror m = 2, In-pile Straight Section, {approx} 5 m Curved Guide, {approx} 26 m w/ R 1500 m Straight Guide before the Instrument, {approx} 40 m Filters PG and Be Neutron Velocity Selector (Future) Monochromators Vertically Focusing Monochromators PG(002) and Heusler(111) Doubly Focusing Monochromators (Future) Monochromator-Sample Distance 2 m Collimation C1 Soller Collimators, 20', 40' 80'Beam Height at the Sample Table 1.5 m Sample-Analyzer Distance 1.0 m Collimation C2 Soller Collimators, 20', 40', 80' Radial Collimator Analyzers Horizontally Focusing Analyzers w/ Fixed Vertical Focusing PG(002) and Heusler(111) Analyzer-Detector Distance 0.5 m Detectors 5 cm Tube Detector 25 cm wide Position Sensitive Detector Once completed, the neutron flux at sample is expected to surpass that of SPINS at NCNR, making this instrument one of the most powerful 2nd generation cold neutron triple-axis spectrometers in the world.

  18. VERITAS: Versatile Triple-Axis Spectrometer

    International Nuclear Information System (INIS)

    Park, Sung Il

    2006-04-01

    Korea Atomic Energy Research Institute is planning to build a cold neutron triple-axis spectrometer at HANARO, the 30 MW research reactor. The spectrometer is expected to be completed in 2008 with the following configuration from the upstream to the downstream. Guide Supermirror m = 2, In-pile Straight Section, ∼ 5 m Curved Guide, ∼ 26 m w/ R 1500 m Straight Guide before the Instrument, ∼ 40 m Filters PG and Be Neutron Velocity Selector (Future) Monochromators Vertically Focusing Monochromators PG(002) and Heusler(111) Doubly Focusing Monochromators (Future) Monochromator-Sample Distance 2 m Collimation C1 Soller Collimators, 20', 40' 80'Beam Height at the Sample Table 1.5 m Sample-Analyzer Distance 1.0 m Collimation C2 Soller Collimators, 20', 40', 80' Radial Collimator Analyzers Horizontally Focusing Analyzers w/ Fixed Vertical Focusing PG(002) and Heusler(111) Analyzer-Detector Distance 0.5 m Detectors 5 cm Tube Detector 25 cm wide Position Sensitive Detector Once completed, the neutron flux at sample is expected to surpass that of SPINS at NCNR, making this instrument one of the most powerful 2nd generation cold neutron triple-axis spectrometers in the world

  19. DALI: Defining Antibiotic Levels in Intensive care unit patients: a multi-centre point of prevalence study to determine whether contemporary antibiotic dosing for critically ill patients is therapeutic.

    Science.gov (United States)

    Roberts, Jason A; De Waele, Jan J; Dimopoulos, George; Koulenti, Despoina; Martin, Claude; Montravers, Philippe; Rello, Jordi; Rhodes, Andrew; Starr, Therese; Wallis, Steven C; Lipman, Jeffrey

    2012-07-06

    The clinical effects of varying pharmacokinetic exposures of antibiotics (antibacterials and antifungals) on outcome in infected critically ill patients are poorly described. A large-scale multi-centre study (DALI Study) is currently underway describing the clinical outcomes of patients achieving pre-defined antibiotic exposures. This report describes the protocol. DALI will recruit over 500 patients administered a wide range of either beta-lactam or glycopeptide antibiotics or triazole or echinocandin antifungals in a pharmacokinetic point-prevalence study. It is anticipated that over 60 European intensive care units (ICUs) will participate. The primary aim will be to determine whether contemporary antibiotic dosing for critically ill patients achieves plasma concentrations associated with maximal activity. Secondary aims will compare antibiotic pharmacokinetic exposures with patient outcome and will describe the population pharmacokinetics of the antibiotics included. Various subgroup analyses will be conducted to determine patient groups that may be at risk of very low or very high concentrations of antibiotics. The DALI study should inform clinicians of the potential clinical advantages of achieving certain antibiotic pharmacokinetic exposures in infected critically ill patients.

  20. DALI: Defining Antibiotic Levels in Intensive care unit patients: a multi-centre point of prevalence study to determine whether contemporary antibiotic dosing for critically ill patients is therapeutic

    Directory of Open Access Journals (Sweden)

    Roberts Jason A

    2012-07-01

    Full Text Available Abstract Background The clinical effects of varying pharmacokinetic exposures of antibiotics (antibacterials and antifungals on outcome in infected critically ill patients are poorly described. A large-scale multi-centre study (DALI Study is currently underway describing the clinical outcomes of patients achieving pre-defined antibiotic exposures. This report describes the protocol. Methods DALI will recruit over 500 patients administered a wide range of either beta-lactam or glycopeptide antibiotics or triazole or echinocandin antifungals in a pharmacokinetic point-prevalence study. It is anticipated that over 60 European intensive care units (ICUs will participate. The primary aim will be to determine whether contemporary antibiotic dosing for critically ill patients achieves plasma concentrations associated with maximal activity. Secondary aims will compare antibiotic pharmacokinetic exposures with patient outcome and will describe the population pharmacokinetics of the antibiotics included. Various subgroup analyses will be conducted to determine patient groups that may be at risk of very low or very high concentrations of antibiotics. Discussion The DALI study should inform clinicians of the potential clinical advantages of achieving certain antibiotic pharmacokinetic exposures in infected critically ill patients.

  1. Usefulness of Non-coplanar Helical Tomotherapy Using Variable Axis Baseplate

    International Nuclear Information System (INIS)

    Ha, Jin Sook; Chung, Yoon Sun; Lee, Ik Jae; Shin, Dong Bong; Kim, Jong Dae; Kim, Sei Joon; Jeon, Mi Jin; Chok, Yoon Jin; Kim, Ki Kwang; Lee, Seul Bee

    2011-01-01

    who did not use, but the mean of Y-axis movement was lower by at least 64%, and the mean of Z-axis was lower by at least 67%, and the mean of Z-axis was lower by at least 67%, and the vector was lower by at least 59% with the use of a mouthpiece. Among these 8 patients, one patient whose tumor was located on left frontal lobe and left basal ganglia received reduced radiation dose of 38% in right eye, 23% in left eye, 30% in optic chiasm, 27% in brain stem, and 8% in normal brain with non-coplanar method. Tomotherapy only allows coplanar delivery of IMRT treatment. To complement this shortcoming, Tomotherapy can be used with non-coplanar method by artificially tilting the patient's head and using an oral immobilization instrument to minimize the movement of patient, when intracranial tumor locates near critical organs or has to be treated with high dose radiation.

  2. Computer generation of cobalt-60 single beam dose distribution using an analytical beam model

    International Nuclear Information System (INIS)

    Jayaraman, S.

    1981-01-01

    A beam dose calculation model based on evaluation of tissue air ratios (TAR) and scatter air ratios (SAR) for cobalt-60 beams of rectangular cross section has been developed. Off-central axis fall-off of primary radiation intensity is derived by an empirical formulation involving an arctangent function with the slope of the geometrical penumbra acting as an essential constant. Central axis TAR and SAR values are assessed by semi-empirical polynomial expressions employing the two sides of the rectangular field as the bariables. The model utilises a minimum number of parametric constants and is useful for computer generation of isodose curves. The model is capable of accounting for situations where wedge filters or split field shielding blocks, are encountered. Further it could be widely applied with minor modifications to several makes of the currently available cobalt-60 units. The paper explains the model and shows examples of the results obtained in comparison with the corresponding experimentally determined dose distributions. (orig.) [de

  3. Cervical cancer: intracavitary dose specification and prescription

    International Nuclear Information System (INIS)

    Potish, R.A.; Gerbi, B.J.

    1987-01-01

    Dose and volume specifications for reporting intracavitary therapy were analyzed according to criteria recommended by the International Commission on Radiation Units and Measurements (ICRU). Ninety Fletcher-Suit radium applications were studied to examine the validity of the assumptions of the ICRU and the merit of their routine reporting. It was demonstrated that the reporting recommendations were inconsistent with clinical prescription systems and added little to dose specification. The distinction between dose specification and dose prescription was stressed

  4. Field size and dose distribution of electron beam

    International Nuclear Information System (INIS)

    Kang, Wee Saing

    1980-01-01

    The author concerns some relations between the field size and dose distribution of electron beams. The doses of electron beams are measured by either an ion chamber with an electrometer or by film for dosimetry. We analyzes qualitatively some relations; the energy of incident electron beams and depths of maximum dose, field sizes of electron beams and depth of maximum dose, field size and scatter factor, electron energy and scatter factor, collimator shape and scatter factor, electron energy and surface dose, field size and surface dose, field size and central axis depth dose, and field size and practical range. He meets with some results. They are that the field size of electron beam has influence on the depth of maximum dose, scatter factor, surface dose and central axis depth dose, scatter factor depends on the field size and energy of electron beam, and the shape of the collimator, and the depth of maximum dose and the surface dose depend on the energy of electron beam, but the practical range of electron beam is independent of field size

  5. The Proline Regulatory Axis and Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Phang, James Ming; Liu, Wei; Hancock, Chad; Christian, Kyle J., E-mail: phangj@mail.nih.gov [Metabolism and Cancer Susceptibility Section, Basic Research Laboratory, Center for Cancer Research, Frederick National Laboratory for Cancer Research, Frederick, MD (United States)

    2012-06-21

    Studies in metabolism and cancer have characterized changes in core pathways involving glucose and glutamine, emphasizing the provision of substrates for building cell mass. But recent findings suggest that pathways previously considered peripheral may play a critical role providing mechanisms for cell regulation. Several of these mechanisms involve the metabolism of non-essential amino acids, for example, the channeling of glycolytic intermediates into the serine pathway for one-carbon transfers. Historically, we proposed that the proline biosynthetic pathway participated in a metabolic interlock with glucose metabolism. The discovery that proline degradation is activated by p53 directed our attention to the initiation of apoptosis by proline oxidase/dehydrogenase. Now, however, we find that the biosynthetic mechanisms and the metabolic interlock may depend on the pathway from glutamine to proline, and it is markedly activated by the oncogene MYC. These findings add a new dimension to the proline regulatory axis in cancer and present attractive potential targets for cancer treatment.

  6. Polarized triple-axis spectrometer TASP

    Energy Technology Data Exchange (ETDEWEB)

    Boeni, P; Keller, P [Lab. for Neutron Scattering ETH Zurich, Zurich (Switzerland) and Paul Scherrer Institute, Villigen (Switzerland)

    1996-11-01

    The polarized triple-axis spectrometer TASP at SINQ has been optimized for measuring magnetic cross sections in condensed matter. The neutrons are polarized or analyzed either by means of benders or Heusler monochromators. The beam divergence, i.e. the intensity, and the spectral range of the neutrons is rather large because of the supermirror coatings of the feeding neutron guide. The intensity can be further increased at the sample position by means of a focussing monochromator and a focussing anti-trumpet. The end position of TASP allows the tailoring of the neutron beam already before the monochromator and to scatter neutrons over very wide ranges of angles. (author) 6 figs., 1 tab., 8 refs.

  7. A Portable Single Axis Magnetic Gradiometer

    DEFF Research Database (Denmark)

    Merayo, José M.G.; Petersen, Jan Raagaard; Nielsen, Otto V

    2001-01-01

    not provide vector information about the magnetic field. Secondly, one of the sensors measures the ambient magnetic field and is used to compensate for the main field at both sensors. Several methods have been developed for characterization of the 2 gradiometer, and the calibration of the gradient......The single axis magnetic gradiometer based on two compact detector compensation (CDC) fluxgate ringcore sensors separated 20 cm is described. Despite its high stability and precision better than 1 nT, the calibration procedures are not straightforward. Firstly, the mono-axial measurement does...... measurements is achieved by using a magnetic dipole of strength 2 mAm(2). In a coil facility, the gradient can be determined with an accuracy of 0.3 nT/m(RMS)....

  8. RITA-type triple axis spectrometers

    International Nuclear Information System (INIS)

    Roennow, H.M.

    2001-01-01

    The RITA spectrometer at Risoe National Laboratory was the first to incorporate a complete re-thinking of the neutron-path from source, through detector to analysis. Since then, other RITA-type spectrometers such as SPINS at NIST, RITA-II at PSI have been built, and several new spectrometers around the world are adapting the same philosophy. The main novelty of RITA was the introduction of a single back-end tank featuring both an analyser block with multiple individually turnable analyser blades and a 2D position sensitive detector. Several new triple-axis spectrometers are presently being built at existing and future sources, and almost all of them have learnt from the experience with RITA. (R.P.)

  9. Dose rate constants for new dose quantities

    International Nuclear Information System (INIS)

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

    1992-01-01

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

  10. Radiation doses during chest examinations using dose modulation techniques in multislice CT scanner

    OpenAIRE

    Livingstone Roshan; Pradip Joe; Dinakran Paul; Srikanth B

    2010-01-01

    Objective: To evaluate the radiation dose and image quality using a manual protocol and dose modulation techniques in a 6-slice CT scanner. Materials and Methods: Two hundred and twenty-one patients who underwent contrast-enhanced CT of the chest were included in the study. For the manual protocol settings, constant tube potential (kV) and tube current-time product (mAs) of 140 kV and 120 mAs, respectively, were used. The angular and z-axis dose modulation techniques utilized a constant tu...

  11. Dose Distribution of Rectum and Bladder in Intracavitary Irradiation

    International Nuclear Information System (INIS)

    Chu, S. S.; Oh, W. Y.; Suh, C. O.; Kim, G. E.

    1984-01-01

    The intrauterine irradiation is essential to achieve adequate tumor dose to central tumor mass of uterine malignancy in radiotherapy. The complications of pelvic organ are known to be directly related to radiation dose and physical parameters. The simulation radiogram and medical records of 206 patients, who were treated with intrauterine irradiation from Feb. 1983 to Oct. 1983, were critically analyzed. The physical parameters to include distances between lateral walls of vaginal fornices, longitudinal and lateral cervix to the central axis of ovoid were measured for low dose rate irradiation system and high dose rate remote control after loading system. The radiation doses and dose distributions within cervical area including interesting points and bladder, rectum, according to sources arrangement and location of applicator, were estimated with personal computer. Followings were summary of study results; 1. In distances between lateral walls of vaginal fornices, the low dose rate system showed as 4-7cm width and high dose rate system showed as 5-6cm. 2. In Horizontal angulation of tandem to body axis, the low dose rate system revealed mid position 64.6%, left deviation 19.2% and right deviation 16.2%. 3. In longitudinal angulation of tandem to body axis, the mid position was 11.8% and anterior angulation 88.2% in low dose rate system but in high dose rate system, anterior angulation was 98.5%. 4. Down ward displacement of ovoid below external os was only 3% in low dose rate system and 66.6% in high dose rate system. 5. In radiation source arrangement, the most activities of tandem and ovoid were 35 by 30 in low dose rate system but 50 by 40 in high dose rate system. 6. In low and high dose rate system, the total doses and TDF were 80, 70 Gy and 131, 123 including 40 Gy external irradiation. 7. The doses and TDF in interesting points Co, B, were 98, 47 Gy and 230, 73 in high dose rate system but in low dose rate system 125, 52 Gy and 262, 75 respectively. 8. Doses

  12. Investigation of intracranial peripheral dose arising from the treatment of large lesions with Leksell GammaKnife Perfexion.

    Science.gov (United States)

    Ruschin, Mark; Nordström, Håkan; Kjäll, Per; Cho, Young-Bin; Jaffray, David

    2009-06-01

    This investigation involves quantifying the extent of intracranial peripheral dose arising from simulated targets situated in the skull-base or upper-spine region using the Leksell GammaKnife Perfexion treatment unit. For each of three spherical target volumes--denoted as Vs (4 cm3), VM (18 cm3), and VL (60 cm3)--three treatment plans were manually generated, one for each of the three collimator sizes--4, 8, and 16 mm. Each of the plans was delivered to a spherical dosimetry phantom with an insert containing EBT Gafchromic film. The total dose at 70 mm from the targets' edges, %D(70 mm), was measured as a function of elevation angle and expressed as a percentage of the prescription dose. The film insert was placed centered in the median sagittal plane (Leksell X = 100) and %D(70 mm) was measured for the angular range from 0 degree (superior/along Z axis) to 90 degrees (anterior/along Y axis). For a given collimator i, the irradiation time ti to treat a spherical target of volume V using the 50% isodose line was observed to follow a power-law relationship of the form ti = Ai(V/ Vi)n where Ai was the maximum dose divided by collimator dose rate and Vi was the volume encompassed by the 50% isodose line for a single shot. The mean value of n was 0.61 (range: 0.61-0.62). Along the superior (Z) direction (angle=0 degree) and up to angles of around 30 degrees, the %D(70 mm) was always highest for the 4 mm plans, followed by the 8 mm, followed by the 16 mm. In this angular range, the maximum measured %D(70 mm) was 1.7% of the prescription dose. The intracranial peripheral dose along the superior direction (combined scatter and leakage dose) resulting from irradiation of upper-spine or base-of-skull lesions is measured to be less than 2% of the prescription dose, even for very large (60 cm3) targets. The results of this study indicate that, for a given target volume, treatment plans consisting of only 4 mm shots yield larger peripheral dose in the superior direction than 8

  13. Modeling and regression analysis of semiochemical dose-response curves of insect antennal reception and behavior

    Science.gov (United States)

    Dose-response curves with semiochemicals are reported in many articles in insect chemical ecology regarding neurophysiology and behavioral bioassays. Most such curves are shown in figures where the x-axis has order of magnitude increases in dosages versus responses on the y-axis represented by point...

  14. Radiation doses in interventional neuroradiology

    International Nuclear Information System (INIS)

    Theodorakou, C.; Butler, P.; Horrocks, J.A.

    2001-01-01

    Patient radiation doses during interventional radiology (IR) procedures may reach the thresholds for radiation-induced skin and eye lens injuries. This study investigates the radiation doses received by patients undergoing cerebral embolization. Measurements were conducted using thermoluminescent dosimeters. Radiotherapy verification films were used in order to visualise the radiation field. For each procedure the fluoroscopic and digital dose-area product, the fluoroscopic time, the total number of acquired images and entrance-skin dose calculated by the angiographic unit were recorded. In this paper, the skin, eye and thyroid glands doses on a sample of patients are presented. From a preliminary study of 13 patients having undergone cerebral embolization, it was deduced that six of them have received a dose above 1 Gy. Detailed dose data from patients undergoing IR procedures will be collected in the future with the aim of developing a model to allow estimation of the dose prior to the procedure as well as to look at techniques of dose reduction. (author)

  15. Evolution of radon dose evaluation

    Directory of Open Access Journals (Sweden)

    Fujimoto Kenzo

    2004-01-01

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

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

    Science.gov (United States)

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

    2010-01-01

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

  17. Radiation dose rate meter

    International Nuclear Information System (INIS)

    Kronenberg, S.; Siebentritt, C.R.

    1981-01-01

    A combined dose rate meter and charger unit therefor which does not require the use of batteries but on the other hand produces a charging potential by means of a piezoelectric cylinder which is struck by a manually triggered hammer mechanism. A tubular type electrometer is mounted in a portable housing which additionally includes a geiger-muller (Gm) counter tube and electronic circuitry coupled to the electrometer for providing multi-mode operation. In one mode of operation, an rc circuit of predetermined time constant is connected to a storage capacitor which serves as a timed power source for the gm tube, providing a measurement in terms of dose rate which is indicated by the electrometer. In another mode, the electrometer indicates individual counts

  18. Termination unit

    Science.gov (United States)

    Traeholt, Chresten [Frederiksberg, DK; Willen, Dag [Klagshamn, SE; Roden, Mark [Newnan, GA; Tolbert, Jerry C [Carrollton, GA; Lindsay, David [Carrollton, GA; Fisher, Paul W [Heiskell, TN; Nielsen, Carsten Thidemann [Jaegerspris, DK

    2014-01-07

    This invention relates to a termination unit comprising an end-section of a cable. The end section of the cable defines a central longitudinal axis and comprising end-parts of N electrical phases, an end-part of a neutral conductor and a surrounding thermally insulation envelope adapted to comprising a cooling fluid. The end-parts of the N electrical phases and the end-part of the neutral conductor each comprising at least one electrical conductor and being arranged in the cable concentrically around a core former with a phase 1 located relatively innermost, and phase N relatively outermost in the cable, phase N being surrounded by the neutral conductor, electrical insulation being arrange between neighboring electrical phases and between phase N and the neutral conductor, and wherein the end-parts of the neutral conductor and the electrical phases each comprise a contacting surface electrically connected to at least one branch current lead to provide an electrical connection: The contacting surfaces each having a longitudinal extension, and being located sequentially along the longitudinal extension of the end-section of the cable. The branch current leads being individually insulated from said thermally insulation envelope by individual electrical insulators.

  19. Analysis and design of a vertical axis wind turbine

    OpenAIRE

    Goyena Iriso, Joseba

    2011-01-01

    The main objective of this project is to design a new vertical axis wind turbine, specifically one Giromill wind turbine. The project development requires performing a previous study of the vertical axis wind turbines currently development. This study has to be performed before starting to design the wind turbine. Other very important aim is the development of a new vertical axis wind turbine. The after analyses that will result in the final design of the wind turbine will b...

  20. Self-starting aerodynamics analysis of vertical axis wind turbine

    OpenAIRE

    Jianyang Zhu; Hailin Huang; Hao Shen

    2015-01-01

    Vertical axis wind turbine is a special type of wind-force electric generator which is capable of working in the complicated wind environment. The self-starting aerodynamics is one of the most important considerations for this kind of turbine. This article aims at providing a systematic synthesis on the self-starting aerodynamic characteristics of vertical axis wind turbine based on the numerical analysis approach. First, the physical model of vertical axis wind turbine and its parameter defi...

  1. SU-F-P-47: Estimation of Skin Dose by Performing the Measurements On Cylindrical Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Bosma, S; Sanders, M; Aryal, P [University Kentucky - Chandler Medical Ctr, Lexington, KY (United States)

    2016-06-15

    Purpose: To evaluate the skin dose by performing the measurements on cylindrical phantom with 6X beam. Methods: A cylindrical phantom was used to best model a patient surface. The source to surface distance (SSD) was 100 cm at phantom surface along central axis (CAX). The EBT2 films were cut into 2×2 cm2 pieces. Each piece of film was placed at CAX on phantom surface for each measurement at 0°, 15°, 30°, 45°, 60°, 75°, and 90° gantry angles for field sizes of 5×5, 10×10, 15×15, and 20×20 cm{sup 2} respectively. One hundred monitor units (MU) with 6X beam were delivered for each set up. Similarly, the measurements were repeated using lithium fluoride (LiF) thermoluminescent dosimeter (TLD) chips (1X1X1 mm{sup 3}). Two TLD chips were placed for each gantry angle and field size. The calibration curves were produced for both film and TLD. The computed tomography (CT) was also performed on the same cylindrical phantom and dose was evaluated at the phantom surface using Eclipse treatment planning system ( AAA algorithm) for skin dose comparison. Results: Data showed small differences at smaller angles among EBT2, TLD and Eclipse treatment planning system. But Eclipse treatment planning system under estimated the skin dose between 20% and 50% at larger gantry angles (between 40° and 80°) at all field sizes before dose differences began to converge. Conclusion: Given this data, we can conclude that Eclipse treatment planning system under estimated the dose especially between 40 and 80 degrees of obliquity compared to the measurements results. Ideally, this study can be applied largely to head and neck patients where contours differ drastically and where skin dose is paramount.

  2. Intravascular ultrasound based dose assessment in endovascular brachytherapy

    International Nuclear Information System (INIS)

    Catalano, Gianpiero; Tamburini, Vittorio; Colombo, Antonio; Nishida, Takahiro; Parisi, Giovanni; Mazzetta, Chiara; Orecchia, Roberto

    2003-01-01

    Background: the role of endovascular brachytherapy in restenosis prevention is well documented. Dose is usually prescribed at a fixed distance from the source axis by angiographic quantification of vessel diameter. Recently, intravascular ultrasound (IVUS) was introduced in dose prescription, allowing a better evaluation of the vessel anatomy. This study retrospectively explores the difference between prescription following angiographic vessel sizing and delivered dose calculated with IVUS. Methods and results: Seventeen lesions were studied with IVUS, identifying on irradiated segment, three sections on which measuring minimal and maximal distance from the centre of IVUS catheter to the adventitia; using dedicated software, corresponding doses were calculated. The dose ranged widely, with maximal and minimal values of 71.6 and 4.9 Gy; furthermore, heterogeneity in dose among different sections was observed. In the central section, the maximal dose was 206% of the one prescribed with the QCA model at 2 mm from the source axis, while the minimal dose was 96%. In proximal and distal sections, respective values were 182, 45, 243, and 122%. Conclusions: Our analysis confirmed the dose inhomogeneity delivered with an angiographic fixed-dose prescription strategy. A dose variation was found along the irradiated segment due to the differences in vessel thickness. IVUS emerged as an important tool in endovascular brachytherapy, especially for irregular-shaped vessels

  3. Concept of a Programmable Fixture for 3-Axis CNC

    Directory of Open Access Journals (Sweden)

    Ahmad Dalloul

    2017-09-01

    Full Text Available CNC machine is the one of the major reasons for industrial advancement in recent decades for its ability of producing accurate parts. The most commen CNC machines are of 3-axis and adopted widely in the industrial sector. However, for producing more complicated parts 5-axis CNC machines are required. Although the introduction of the 5-axis machine came after the 3-axis CNC machine has established itself and many manufacturers did not make the move toward the newer model and its high pricing compared to the 3-axis model did not help either. In this time the development of a fixture or a platform to help transfer the 3-axis to a 5-axis to some degree. This paper discusses the concept of a programmable fixture that gives 3-axis CNC machine the freedom to act in similar manner as the 5-axis. The paper describes the mechanism with some initial results of the testing. Result showed that the platform moves in translation manner with an average error of 5.58 % and 7.303% average error for rotation movement.

  4. Suicidal behavior on Axis VI: clinical data supporting a sixth Axis for DSM-V.

    Science.gov (United States)

    Van Orden, Kimberly A; Witte, Tracy K; Holm-Denoma, Jill; Gordon, Kathryn H; Joiner, Thomas E

    2011-01-01

    Oquendo and colleagues (Oquendo, Baca-García, Mann, & Giner, 2008; Oquendo & Currier, 2009) recommend that DSM-V emphasize suicide risk assessment on a sixth axis, thereby increasing regularity of suicide risk assessments. We propose that evidence of nonredundancy with Axis V - Global Assessment of Functioning (GAF) is one piece of data that can serve as a starting point for a line of research establishing incremental predictive utility for a separate suicide risk assessment in the DSM framework. A standardized suicide risk assessment protocol, measures of depressive, anxious, and eating disordered symptomatology, as well as an index of comorbidity were administered to a sample of 412 adult outpatients. Our data indicate that data from standardized suicide risk assessments are associated with indices of symptomatology severity as well as comorbidity, controlling for GAF. These results support the nonredundancy of the assessments and suggest the utility of longitudinal investigations of the predictive utility of a sixth DSM axis in the assessment of suicide risk.

  5. A self-calibration method in single-axis rotational inertial navigation system with rotating mechanism

    Science.gov (United States)

    Chen, Yuanpei; Wang, Lingcao; Li, Kui

    2017-10-01

    Rotary inertial navigation modulation mechanism can greatly improve the inertial navigation system (INS) accuracy through the rotation. Based on the single-axis rotational inertial navigation system (RINS), a self-calibration method is put forward. The whole system is applied with the rotation modulation technique so that whole inertial measurement unit (IMU) of system can rotate around the motor shaft without any external input. In the process of modulation, some important errors can be decoupled. Coupled with the initial position information and attitude information of the system as the reference, the velocity errors and attitude errors in the rotation are used as measurement to perform Kalman filtering to estimate part of important errors of the system after which the errors can be compensated into the system. The simulation results show that the method can complete the self-calibration of the single-axis RINS in 15 minutes and estimate gyro drifts of three-axis, the installation error angle of the IMU and the scale factor error of the gyro on z-axis. The calibration accuracy of optic gyro drifts could be about 0.003°/h (1σ) as well as the scale factor error could be about 1 parts per million (1σ). The errors estimate reaches the system requirements which can effectively improve the longtime navigation accuracy of the vehicle or the boat.

  6. Multi-Axis Thrust Measurements of the EO-1 Pulsed Plasma Thruster

    Science.gov (United States)

    Arrington, Lynn A.; Haag, Thomas W.

    1999-01-01

    Pulsed plasma thrusters are low thrust propulsive devices which have a high specific impulse at low power. A pulsed plasma thruster is currently scheduled to fly as an experiment on NASA's Earth Observing-1 satellite mission. The pulsed plasma thruster will be used to replace one of the reaction wheels. As part of the qualification testing of the thruster it is necessary to determine the nominal thrust as a function of charge energy. These data will be used to determine control algorithms. Testing was first completed on a breadboard pulsed plasma thruster to determine nominal or primary axis thrust and associated propellant mass consumption as a function of energy and then later to determine if any significant off-axis thrust component existed. On conclusion that there was a significant off-axis thrust component with the bread-board in the direction of the anode electrode, the test matrix was expanded on the flight hardware to include thrust measurements along all three orthogonal axes. Similar off-axis components were found with the flight unit.

  7. Fast phase processing in off-axis holography by CUDA including parallel phase unwrapping.

    Science.gov (United States)

    Backoach, Ohad; Kariv, Saar; Girshovitz, Pinhas; Shaked, Natan T

    2016-02-22

    We present parallel processing implementation for rapid extraction of the quantitative phase maps from off-axis holograms on the Graphics Processing Unit (GPU) of the computer using computer unified device architecture (CUDA) programming. To obtain efficient implementation, we parallelized both the wrapped phase map extraction algorithm and the two-dimensional phase unwrapping algorithm. In contrast to previous implementations, we utilized unweighted least squares phase unwrapping algorithm that better suits parallelism. We compared the proposed algorithm run times on the CPU and the GPU of the computer for various sizes of off-axis holograms. Using the GPU implementation, we extracted the unwrapped phase maps from the recorded off-axis holograms at 35 frames per second (fps) for 4 mega pixel holograms, and at 129 fps for 1 mega pixel holograms, which presents the fastest processing framerates obtained so far, to the best of our knowledge. We then used common-path off-axis interferometric imaging to quantitatively capture the phase maps of a micro-organism with rapid flagellum movements.

  8. Assessment and validation of CT scanogram to compare per-operative and post-operative mechanical axis after navigated total knee replacement

    Science.gov (United States)

    Jain, Sunil

    2008-01-01

    Our objective was to assess and validate low-dose computed tomography (CT) scanogram as a post-operative imaging modality to measure the mechanical axis after navigated total knee replacement. A prospective study was performed to compare intra-operative and post-operative mechanical axis after navigated total knee replacements. All consecutive patients who underwent navigated total knee replacement between May and December 2006 were included. The intra-operative final axis was recorded, and post-operatively a CT scanogram of lower limbs was performed. The mechanical axis was measured and compared against the intra-operative measurement. There were 15 patients ranging in age from 57 to 80 (average 70) years. The average final intra-operative axis was 0.56° varus (4° varus to 1.5° valgus) and post-operative CT scanogram axis was 0.52° varus (3.1° varus to 1.8° valgus). The average deviation from final axes to CT scanogram axes was 0.12° valgus with a correlation coefficient of 0.9. Our study suggests that CT scanogram is an imaging modality with reasonable accuracy for measuring mechanical axis despite significantly low radiation. It also confirms a high level of correlation between intra-operative and post-operative mechanical axis after navigated total knee replacement. PMID:18696064

  9. Effective solidity in vertical axis wind turbines

    Science.gov (United States)

    Parker, Colin M.; Leftwich, Megan C.

    2016-11-01

    The flow surrounding vertical axis wind turbines (VAWTs) is investigated using particle imaging velocimetry (PIV). This is done in a low-speed wind tunnel with a scale model that closely matches geometric and dynamic properties tip-speed ratio and Reynolds number of a full size turbine. Previous results have shown a strong dependance on the tip-speed ratio on the wake structure of the spinning turbine. However, it is not clear whether this is a speed or solidity effect. To determine this, we have measured the wakes of three turbines with different chord-to-diameter ratios, and a solid cylinder. The flow is visualized at the horizontal mid-plane as well as the vertical mid-plane behind the turbine. The results are both ensemble averaged and phase averaged by syncing the PIV system with the rotation of the turbine. By keeping the Reynolds number constant with both chord and diameter, we can determine how each effects the wake structure. As these parameters are varied there are distinct changes in the mean flow of the wake. Additionally, by looking at the vorticity in the phase averaged profiles we can see structural changes to the overall wake pattern.

  10. Yaw dynamics of horizontal axis wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, A.C. (Utah Univ., Salt Lake City, UT (United States))

    1992-05-01

    Designers of a horizontal axis wind turbine yaw mechanism are faced with a difficult decision. They know that if they elect to use a yaw- controlled rotor then the system will suffer increased initial cost and increased inherent maintenance and reliability problems. On the other hand, if they elect to allow the rotor to freely yaw they known they will have to account for unknown and random, though bounded, yaw rates. They will have a higher-risk design to trade-off against the potential for cost savings and reliability improvement. The risk of a yaw-free system could be minimized if methods were available for analyzing and understanding yaw behavior. The complexity of yaw behavior has, until recently, discouraged engineers from developing a complete yaw analysis method. The objectives of this work are to (1) provide a fundamental understanding of free-yaw mechanics and the design concepts most effective at eliminating yaw problems, and (2) provide tested design tools and guidelines for use by free-yaw wind systems manufacturers. The emphasis is on developing practical and sufficiently accurate design methods.

  11. Six axis force feedback input device

    Science.gov (United States)

    Ohm, Timothy (Inventor)

    1998-01-01

    The present invention is a low friction, low inertia, six-axis force feedback input device comprising an arm with double-jointed, tendon-driven revolute joints, a decoupled tendon-driven wrist, and a base with encoders and motors. The input device functions as a master robot manipulator of a microsurgical teleoperated robot system including a slave robot manipulator coupled to an amplifier chassis, which is coupled to a control chassis, which is coupled to a workstation with a graphical user interface. The amplifier chassis is coupled to the motors of the master robot manipulator and the control chassis is coupled to the encoders of the master robot manipulator. A force feedback can be applied to the input device and can be generated from the slave robot to enable a user to operate the slave robot via the input device without physically viewing the slave robot. Also, the force feedback can be generated from the workstation to represent fictitious forces to constrain the input device's control of the slave robot to be within imaginary predetermined boundaries.

  12. Creating a Multi-axis Machining Postprocessor

    Directory of Open Access Journals (Sweden)

    Petr Vavruška

    2012-01-01

    Full Text Available This paper focuses on the postprocessor creation process. When using standard commercially available postprocessors it is often very difficult to modify its internal source code, and it is a very complex process, in many cases even impossible, to implement the newly-developed functions. It is therefore very important to have a method for creating a postprocessor for any CAM system, which allows CL data (Cutter Location data to be generated to a separate text file. The goal of our work is to verify the proposed method for creating a postprocessor. Postprocessor functions for multi-axis machiningare dealt with in this work. A file with CL data must be translated by the postprocessor into an NC program that has been customized for a specific production machine and its control system. The postprocessor is therefore verified by applications for machining free-form surfaces of complex parts, and by executing the NC programs that are generated on real machine tools. This is also presented here.

  13. Relationships of neuroticism and extraversion with axis I and II comorbidity among patients with DSM-IV major depressive disorder.

    Science.gov (United States)

    Jylhä, Pekka; Melartin, Tarja; Isometsä, Erkki

    2009-04-01

    High comorbidity with axis I and II disorders among major depressive disorder (MDD) patients may in part be due to the predisposing personality dimensions of neuroticism and extraversion. However, a comprehensive view of this relationship is lacking. MDD patients (n=193) in the Vantaa Depression Study were interviewed at baseline and at 6 and 18 months with the SCAN and SCID-II, and a general population comparison group (n=388) surveyed by mail. Neuroticism and extraversion were measured with the Eysenck Personality Inventory. A dose-exposure relationship between standardized levels of neuroticism and extraversion and type and number of comorbid axis I and II disorders among patients with MDD was hypothesized. Prevalence and number of comorbid axis I and II disorders increased significantly with increasing level of neuroticism. In contrast, as the level of extraversion increased, the prevalences of social phobia and cluster C personality disorders decreased. Patients with pure MDD or with any comorbid axis I or II disorder had z-scores of neuroticism of +0.46, +0.90 and +1.30 and of extraversion of -0.34, -0.47 and -0.84, respectively. Patients' personality scores were not pre-morbid. Among MDD patients, a positive dose-exposure relationship appears to exist between neuroticism and prevalence and number of comorbid axis I and II disorders. A negative relationship exists between level of extraversion and prevalence of social phobia and cluster C personality disorders. These findings are consistent with the hypothesis that high neuroticism and low extraversion predispose to comorbid axis I and II disorders among patients with MDD.

  14. Distortion definition and correction in off-axis systems

    Science.gov (United States)

    Da Deppo, Vania; Simioni, Emanuele; Naletto, Giampiero; Cremonese, Gabriele

    2015-09-01

    Off-axis optical configurations are becoming more and more used in a variety of applications, in particular they are the most preferred solution for cameras devoted to Solar System planets and small bodies (i.e. asteroids and comets) study. Off-axis designs, being devoid of central obstruction, are able to guarantee better PSF and MTF performance, and thus higher contrast imaging capabilities with respect to classical on-axis designs. In particular they are suitable for observing extended targets with intrinsic low contrast features, or scenes where a high dynamical signal range is present. Classical distortion theory is able to well describe the performance of the on-axis systems, but it has to be adapted for the off-axis case. A proper way to deal with off-axis distortion definition is thus needed together with dedicated techniques to accurately measure and hence remove the distortion effects present in the acquired images. In this paper, a review of the distortion definition for off-axis systems will be given. In particular the method adopted by the authors to deal with the distortion related issues (definition, measure, removal) in some off-axis instruments will be described in detail.

  15. A psychology of the human brain-gut-microbiome axis.

    Science.gov (United States)

    Allen, Andrew P; Dinan, Timothy G; Clarke, Gerard; Cryan, John F

    2017-04-01

    In recent years, we have seen increasing research within neuroscience and biopsychology on the interactions between the brain, the gastrointestinal tract, the bacteria within the gastrointestinal tract, and the bidirectional relationship between these systems: the brain-gut-microbiome axis. Although research has demonstrated that the gut microbiota can impact upon cognition and a variety of stress-related behaviours, including those relevant to anxiety and depression, we still do not know how this occurs. A deeper understanding of how psychological development as well as social and cultural factors impact upon the brain-gut-microbiome axis will contextualise the role of the axis in humans and inform psychological interventions that improve health within the brain-gut-microbiome axis. Interventions ostensibly aimed at ameliorating disorders in one part of the brain-gut-microbiome axis (e.g., psychotherapy for depression) may nonetheless impact upon other parts of the axis (e.g., microbiome composition and function), and functional gastrointestinal disorders such as irritable bowel syndrome represent a disorder of the axis, rather than an isolated problem either of psychology or of gastrointestinal function. The discipline of psychology needs to be cognisant of these interactions and can help to inform the future research agenda in this emerging field of research. In this review, we outline the role psychology has to play in understanding the brain-gut-microbiome axis, with a focus on human psychology and the use of research in laboratory animals to model human psychology.

  16. Late Presentation of a Type III Axis Fracture with Spondyloptosis

    Science.gov (United States)

    Jayakumar, Prakash; Choi, David; Casey, Adrian

    2008-01-01

    A 58-year-old man presented with an undiagnosed Effendi type III classification fracture and spondyloptosis of the axis with remarkably normal neurology. We discuss his surgery 4 years since the initial injury, and the presentation, features and management of fractures of the axis. PMID:18430325

  17. Axis: Generating Explanations at Scale with Learnersourcing and Machine Learning

    Science.gov (United States)

    Williams, Joseph Jay; Kim, Juho; Rafferty, Anna; Heffernan, Neil; Maldonado, Samuel; Gajos, Krzysztof Z.; Lasecki, Walter S.; Heffernan, Neil

    2016-01-01

    While explanations may help people learn by providing information about why an answer is correct, many problems on online platforms lack high-quality explanations. This paper presents AXIS (Adaptive eXplanation Improvement System), a system for obtaining explanations. AXIS asks learners to generate, revise, and evaluate explanations as they solve…

  18. Angular momentum projection of tilted axis rotating states

    Energy Technology Data Exchange (ETDEWEB)

    Oi, M; Onishi, N; Tajima, N [Tokyo Univ. (Japan); Horibata, T

    1998-03-01

    We applied an exact angular momentum projection to three dimensional cranked HFB (3d-CHFB) states. Tilted axis rotating states (TAR) and principal axis rotating states (PAR) are compared. It is shown that TAR is more adequate than PAR for description of the back bending phenomena driven by tilted rotation or wobbling motion. (author)

  19. A psychology of the human brain–gut–microbiome axis

    Science.gov (United States)

    Allen, Andrew P.; Dinan, Timothy G.; Clarke, Gerard

    2017-01-01

    Abstract In recent years, we have seen increasing research within neuroscience and biopsychology on the interactions between the brain, the gastrointestinal tract, the bacteria within the gastrointestinal tract, and the bidirectional relationship between these systems: the brain–gut–microbiome axis. Although research has demonstrated that the gut microbiota can impact upon cognition and a variety of stress‐related behaviours, including those relevant to anxiety and depression, we still do not know how this occurs. A deeper understanding of how psychological development as well as social and cultural factors impact upon the brain–gut–microbiome axis will contextualise the role of the axis in humans and inform psychological interventions that improve health within the brain–gut–microbiome axis. Interventions ostensibly aimed at ameliorating disorders in one part of the brain–gut–microbiome axis (e.g., psychotherapy for depression) may nonetheless impact upon other parts of the axis (e.g., microbiome composition and function), and functional gastrointestinal disorders such as irritable bowel syndrome represent a disorder of the axis, rather than an isolated problem either of psychology or of gastrointestinal function. The discipline of psychology needs to be cognisant of these interactions and can help to inform the future research agenda in this emerging field of research. In this review, we outline the role psychology has to play in understanding the brain–gut–microbiome axis, with a focus on human psychology and the use of research in laboratory animals to model human psychology. PMID:28804508

  20. The Performance Characteristics of a Closed Loop, One Axis ...

    African Journals Online (AJOL)

    This paper presents a closed loop one axis solar tracking device of the polar axis type, which achieves an accurate tracking of the sun with a steady state error of less, than 2%. This prototype uses a photo-sensing system to generate an error signal. This error signal switches on a relay, which actuates an electromechanical ...

  1. The hypothalamo-pituitary-adrenal axis in major affective disorder

    DEFF Research Database (Denmark)

    Christensen, M V; Kessing, L V

    2001-01-01

    disorder. The HPA axis is a complex neuroendocrine network with multiple integrated levels of control, and it is likely that the dysregulation involves abnormalities at several sites within the axis. At present, it is not clear whether the abnormalities are related to the affective episodes only......This paper reviews studies of the hypothalamo-pituitary-adrenal (HPA)-axis activity in patients with affective disorders. It is concluded that, despite methodological drawbacks in most studies, dysregulation of the HPA axis seems to be a consistent finding in a proportion of patients with affective...... or to the disorder itself. There is a need for prospective studies of larger samples of patients to be followed during successive affective episodes with a combination of measurements of the HPA-axis activity and brain imaging....

  2. Shot H3837: Darht's First Dual-Axis Explosive Experiment

    Science.gov (United States)

    Mendez, Jacob; McNeil, Wendy Vogan; Harsh, James; Hull, Lawrence

    2011-06-01

    Test H3837 was the first explosive shot performed in front of both flash x-ray axes at the Los Alamos Dual Axis Radiographic HydroTest (DARHT) facility. Executed in November 2009, the shot was an explosively-driven metal flyer plate in a series of experiments designed to explore equation-of-state properties of shocked materials. Imaging the initial shock wave traveling through the flyer plate, DARHT Axis II captured the range of motion from the shock front emergence in the flyer to breakout at the free surface; the Axis I pulse provided a perpendicular perspective of the shot at a time coinciding with the third pulse of Axis II. Since the days of the Manhattan Project, penetrating radiography with multiple frames from different viewing angles has remained a high-profile goal at the Laboratory. H3837 is merely the beginning of a bright future for two-axis penetrating radiography.

  3. Three-Axis Ground Reaction Force Distribution during Straight Walking.

    Science.gov (United States)

    Hori, Masataka; Nakai, Akihito; Shimoyama, Isao

    2017-10-24

    We measured the three-axis ground reaction force (GRF) distribution during straight walking. Small three-axis force sensors composed of rubber and sensor chips were fabricated and calibrated. After sensor calibration, 16 force sensors were attached to the left shoe. The three-axis force distribution during straight walking was measured, and the local features of the three-axis force under the sole of the shoe were analyzed. The heel area played a role in receiving the braking force, the base area of the fourth and fifth toes applied little vertical or shear force, the base area of the second and third toes generated a portion of the propulsive force and received a large vertical force, and the base area of the big toe helped move the body's center of mass to the other foot. The results demonstrate that measuring the three-axis GRF distribution is useful for a detailed analysis of bipedal locomotion.

  4. On a dinosaur axis from one of the oldest dinosaur-bearing sites worldwide

    Directory of Open Access Journals (Sweden)

    Rodrigo T. Müller

    2017-09-01

    Full Text Available The axial skeleton is proportionally underrepresented in the fossil record of early dinosaurs, when compared to other skeletal parts (e.g., pelvic girdle and hindlimb. For instance, the axis is poorly known in early dinosaurs, which precludes a better understanding of this important anatomical structure. Therefore, the present contribution fills an important gap with a description of the axis of a new early dinosaur (CAPPA/UFSM 0179. The specimen was collected at the Buriol outcrop, a Triassic fossiliferous locality from southern Brazil (Candelária Sequence, Santa Maria Supersequence biostratigraphically correlated to Carnian units, placing this specimen among the oldest dinosaurs worldwide. Notable features include the combination of a neural spine that bears an almost straight dorsal margin along its length and presence of an epipophysis. This axis arrangement is unique among Carnian dinosaurs, representing a new morphotype, though a similar morphology is observed in some early theropods. Indeed, a phylogenetic analysis nested the specimen within Theropoda. However, this outcome is probably biased by the large amount of missing data in CAPPA/UFSM 0179 and also due to the limited sampling of the axis in early dinosaurs, particularly among sauropodomorphs. As the specimen comes from the site that includes Buriolestes schultzi (an early sauropodomorph, it is quite plausible that CAPPA/UFSM 0179 might be referable to that taxon. If so, the specimen improves the anatomical knowledge of Buriolestes schultzi, given its axis is yet unknown. An alternative possibility to be considered is that the specimen would belong to a dinosaur not yet known in the Candelária Sequence, which would increase its dinosaur diversity for the outcrop, improving the Triassic dinosaurian record from Southern Brazil.

  5. Determination of localized visibility in off-axis electron holography

    International Nuclear Information System (INIS)

    McLeod, Robert A.; Kupsta, Martin; Malac, Marek

    2014-01-01

    Off-axis electron holography is a wavefront-split interference method for the transmission electron microscope that allows the phase shift and amplitude of the electron wavefront to be separated and quantitatively measured. An additional, third component of the holographic signal is the coherence of the electron wavefront. Historically, wavefront coherence has been evaluated by measurement of the holographic fringe visibility (or contrast) based on the minimum and maximum intensity values. We present a method based on statistical moments is presented that allows allow the visibility to be measured in a deterministic and reproducible fashion suitable for quantitative analysis. We also present an algorithm, based on the Fourier-ratio method, which allows the visibility to be resolved in two-dimensions, which we term the local visibility. The local visibility may be used to evaluate the loss of coherence due to electron scattering within a specimen, or as an aid in image analysis and segmentation. The relationship between amplitude and visibility may be used to evaluate the composition and mass thickness of a specimen by means of a 2-D histogram. Results for a selection of elements (C, Al, Si, Ti, Cr, Cu, Ge, and Au) are provided. All presented visibility metrics are biased at low-dose conditions by the presence of shot-noise, for which we provide methods for empirical normalization to achieve linear response. - Highlights: • Report on a new statistical metric to determine holographic fringe visibility. • Adds new signal to electron holography: measure of electron coherence loss in 2-D. • Provide algorithm to calculate 2-D local visibility map. • Show that amplitude and visibility may be used for compositional analysis and segmentation. • Corrected for data bias such as shot noise

  6. Theoretical performance of cross-wind axis turbines with results for a catenary vertical axis configuration

    Science.gov (United States)

    Muraca, R. J.; Stephens, M. V.; Dagenhart, J. R.

    1975-01-01

    A general analysis capable of predicting performance characteristics of cross-wind axis turbines was developed, including the effects of airfoil geometry, support struts, blade aspect ratio, windmill solidity, blade interference and curved flow. The results were compared with available wind tunnel results for a catenary blade shape. A theoretical performance curve for an aerodynamically efficient straight blade configuration was also presented. In addition, a linearized analytical solution applicable for straight configurations was developed. A listing of the computer program developed for numerical solutions of the general performance equations is included in the appendix.

  7. Radiation and the hypothalamic-pituitary axis

    International Nuclear Information System (INIS)

    Littley, M.D.; Shalet, S.M.; Beardwell, C.G.

    1991-01-01

    This paper reports on radiation therapy which is an essential treatment in the management of many conditions. It is important to appreciate the high incidence of subsequent endocrine morbidity, however, if the hypothalamic pituitary region is within the radiation fields. This is very much more common with external radiation therapy than with other forms of radiation treatment. The dose and fractional of administered radiation are important determinants of the endocrine deficits, their time on onset, and severity. Irradiation of large volumes of brain and hypothalamus may increase the risk of hormonal abnormalities as may preceding surgery in the treatment of pituitary disease. The phenomena observed in children and adults illustrate that there may be damage to pituitary, hypothalamus, and higher centers. In patients who have received a significant radiation dose to the hypothalamic-pituitary region, regular follow-up is mandatory. In adults, surveillance will include pituitary function testing on an annual basis for at least 10 years. In children careful monitoring of growth and pubertal development and early treatment of radiation-induced GH deficiency are vital

  8. Effective shunt impedance comparison between s-band standing wave accelerators with on-axis and off-axis couplers

    International Nuclear Information System (INIS)

    Schriber, S.O.; Funk, L.W.; Hutcheon, R.M.

    1976-01-01

    The effective shunt impedances of a side-coupled S-band standing wave accelerating structure and a structure employing on-axis couplers have been compared by measuring the energy of accelerated electrons. Criteria for choosing an on-axis coupled structure compared to side-coupled and ''disk and washer'' accelerating structures are given. (author)

  9. Bmp suppression in mangrove killifish embryos causes a split in the body axis.

    Directory of Open Access Journals (Sweden)

    Sulayman Mourabit

    Full Text Available Bone morphogenetic proteins (Bmp are major players in the formation of the vertebrate body plan due to their crucial role in patterning of the dorsal-ventral (DV axis. Despite the highly conserved nature of Bmp signalling in vertebrates, the consequences of changing this pathway can be species-specific. Here, we report that Bmp plays an important role in epiboly, yolk syncytial layer (YSL movements, and anterior-posterior (AP axis formation in embryos of the self-fertilizing mangrove killifish, Kryptolebias marmoratus. Stage and dose specific exposures of embryos to the Bmp inhibitor dorsomorphin (DM produced three distinctive morphologies, with the most extreme condition creating the splitbody phenotype, characterised by an extremely short AP axis where the neural tube, somites, and notochord were bilaterally split. In addition, parts of caudal neural tissues were separated from the main body and formed cell islands in the posterior region of the embryo. This splitbody phenotype, which has not been reported in other animals, shows that modification of Bmp may lead to significantly different consequences during development in other vertebrate species.

  10. Binge-pattern alcohol exposure during puberty induces long-term changes in HPA axis reactivity.

    Directory of Open Access Journals (Sweden)

    Magdalena M Przybycien-Szymanska

    2011-04-01

    Full Text Available Adolescence is a dynamic and important period of brain development however, little is known about the long-term neurobiological consequences of alcohol consumption during puberty. Our previous studies showed that binge-pattern ethanol (EtOH treatment during pubertal development negatively dysregulated the responsiveness of the hypothalamo-pituitary-adrenal (HPA axis, as manifested by alterations in corticotrophin-releasing hormone (CRH, arginine vasopressin (AVP, and corticosterone (CORT during this time period. Thus, the primary goal of this study was to determine whether these observed changes in important central regulators of the stress response were permanent or transient. In this study, juvenile male Wistar rats were treated with a binge-pattern EtOH treatment paradigm or saline alone for 8 days. The animals were left undisturbed until adulthood when they received a second round of treatments consisting of saline alone, a single dose of EtOH, or a second binge-pattern treatment paradigm. The results showed that pubertal binge-pattern EtOH exposure induced striking long-lasting alterations of many HPA axis parameters. Overall, our data provide strong evidence that binge-pattern EtOH exposure during pubertal maturation has long-term detrimental effects for the healthy development of the HPA axis.

  11. Analytical calculation of central-axis dosimetric data for a dedicated 6-MV radiosurgery linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Yang, James N.; Pino, Ramiro [Department of Radiation Physics, Unit 94, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030 (United States); Department of Radiology, Baylor College of Medicine and Methodist Hospital, Houston, Texas 77030 (United States)

    2008-10-15

    Narrow beams are extensively used in stereotactic radiosurgery. The accuracy of treatment planning dose calculation depends largely on how well the dosimetric data are measured during the machine commissioning. Narrow beams are characterized by the lack of lateral electronic equilibrium. The lateral electronic disequilibrium in the radiation field and detector's finite size are likely to compromise the accuracy in dose measurements in these beams. This may have a profound impact on outcome in patients who undergo stereotactic radiosurgery. To confirm the measured commissioning data for a dedicated 6-MV linear accelerator-based radiosurgery system, we developed an analytical model to calculate the narrow photon beam central-axis dose. This model is an extension of a previously reported method of Nizin and Mooij for the calculation of the absorbed dose under lateral electronic disequilibrium conditions at depth of d{sub max} or greater. The scatter factor and tissue-maximum ratio were calculated for narrow beams using the parametrized model and compared to carefully measured results for the same beams. For narrow beam radii ranging from 0.2 to 1.5 cm, the differences between the analytical and measured scatter factors were no greater than 1.4%. In addition, the differences between the analytical and measured tissue-maximum ratios were within 3.3% for regions greater than the maximum dose depth. The estimated error of this analytical calculation was less than 2%, which is sufficient to validate measurement results.

  12. Committed dose equivalent per intake of unit activity of radionuclides, for four age-groups, concerning the members of the public for the environmental impact evaluation's of radioactive releases

    International Nuclear Information System (INIS)

    Breuer, F.; Brofferio, C.; Sacripanti, A.

    1983-01-01

    In the present work, with the aim of estimating more realistically the committed dose equivalent for the members of the public in the environmental impact evaluation's of nuclear plants, the authors supply a methodology for calculating the committed dose equivalents for inhalation and ingestion, and the values for fiftheen organs and sixi-three radionuclides, concerning four specific age-groups on the ground of data published by Icrp n.30 part 1, 2, 3

  13. Dose-dependent analysis of acute medical effects of mixed neutron-gamma radiation from selected severe 235U or 239Pu criticality accidents in USSR, United States, and Argentina.

    Science.gov (United States)

    Barabanova, Tatyana; Wiley, Albert L; Bushmanov, Andrey

    2012-04-01

    Eight of the most severe cases of acute radiation disease (ARS) known to have occurred in humans (as the result of criticality accidents) had survival times less than 120 h (herein defined as "early death"). These accidents were analyzed and are discussed with respect to the specific accident scenarios and the resulting accident-specific, mixed neutron-gamma radiation clinical dose distributions. This analysis concludes that the cardiovascular system appears to be the most critical organ system failure for causing "early death" following approximate total body, mixed gamma-neutron radiation doses greater than 40-50 Gy. The clinical data also suggest that there was definite chest dose dependence in the resulting survival times for these eight workers, who unfortunately suffered profound radiation injury and unusual clinical effects from such high dose radiation exposures. In addition, "toxemic syndrome" is correlated with the irradiation of large volumes of soft tissues. Doses to the hands or legs greater than 80-100 Gy or radiation lung injury also play significant but secondary roles in causing "early death" in accidents delivering chest doses greater than 50 Gy.

  14. Estimation of dose enhancement to soft tissue due to backscatter radiation near metal interfaces during head and neck radiothearpy - A phantom dosimetric study with radiochromic film

    Directory of Open Access Journals (Sweden)

    Rajesh Ashok Kinhikar

    2014-01-01

    Full Text Available The objective of this study was to investigate the dose enhancement to soft tissue due to backscatter radiation near metal interfaces during head and neck radiotherapy. The influence of titanium-mandibular plate with the screws on radiation dose was tested on four real bones from mandible with the metal and screws fixed. Radiochromic films were used for dosimetry. The bone and metal were inserted through the film at the center symmetrically. This was then placed in a small jig (7 cm × 7 cm × 10 cm to hold the film vertically straight. The polymer granules (tissue-equivalent were placed around the film for homogeneous scatter medium. The film was irradiated with 6 MV X-rays for 200 monitor units in Trilogy linear accelerator for 10 cm × 10 cm field size with source to axis distance of 100 cm at 5 cm. A single film was also irradiated without any bone and metal interface for reference data. The absolute dose and the vertical dose profile were measured from the film. There was 10% dose enhancement due to the backscatter radiation just adjacent to the metal-bone interface for all the materials. The extent of the backscatter effect was up to 4 mm. There is significant higher dose enhancement in the soft tissue/skin due to the backscatter radiation from the metallic components in the treatment region.

  15. Effect of cyanotoxins on the hypothalamic-pituitary-gonadal axis in male adult mouse.

    Science.gov (United States)

    Xiong, Xiaolu; Zhong, Anyuan; Xu, Huajun

    2014-01-01

    Microcystins LR (MC-LR) are hepatotoxic cyanotoxins that have been shown to induce reproductive toxicity, and Hypothalamic-Pituitary-Gonadal Axis (HPG) is responsible for the control of reproductive functions. However, few studies have been performed to evaluate the effects of MC-LR on HPG axis. This study aimed to investigate the MC-LR-induced toxicity in the reproductive system of mouse and focus on the HPG axis. Adult male C57BL/6 mice were exposed to various concentrations of MC-LR (0, 3.75, 7.50, 15.00 and 30.00 µg/kg body weight per day) for 1 to 14 days, and it was found that exposure to different concentrations of MC-LR significantly disturbed sperm production in the mice testes in a dose- and time-dependent manner. To elucidate the associated possible mechanisms, the serum levels of testosterone, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were assessed. Meanwhile, PCR assays were employed to detect alterations in a series of genes involved in HPG axis, such as FSH, LH, gonadotropin-releasing hormone (GnRH) and their complement receptors. Furthermore, the effect of MC-LR on the viability and testosterone production of Leydig cells were tested in vitro. MC-LR significantly impaired the spermatogenesis of mice possibly through the direct or indirect inhibition of GnRH synthesis at the hypothalamic level, which resulted in reduction of serum levels of LH that lead to suppression of testosterone production in the testis of mice. MC-LR may be a GnRH toxin that would disrupt the reproductive system of mice.

  16. Effect of cyanotoxins on the hypothalamic-pituitary-gonadal axis in male adult mouse.

    Directory of Open Access Journals (Sweden)

    Xiaolu Xiong

    Full Text Available Microcystins LR (MC-LR are hepatotoxic cyanotoxins that have been shown to induce reproductive toxicity, and Hypothalamic-Pituitary-Gonadal Axis (HPG is responsible for the control of reproductive functions. However, few studies have been performed to evaluate the effects of MC-LR on HPG axis. This study aimed to investigate the MC-LR-induced toxicity in the reproductive system of mouse and focus on the HPG axis.Adult male C57BL/6 mice were exposed to various concentrations of MC-LR (0, 3.75, 7.50, 15.00 and 30.00 µg/kg body weight per day for 1 to 14 days, and it was found that exposure to different concentrations of MC-LR significantly disturbed sperm production in the mice testes in a dose- and time-dependent manner. To elucidate the associated possible mechanisms, the serum levels of testosterone, follicle-stimulating hormone (FSH and luteinizing hormone (LH were assessed. Meanwhile, PCR assays were employed to detect alterations in a series of genes involved in HPG axis, such as FSH, LH, gonadotropin-releasing hormone (GnRH and their complement receptors. Furthermore, the effect of MC-LR on the viability and testosterone production of Leydig cells were tested in vitro.MC-LR significantly impaired the spermatogenesis of mice possibly through the direct or indirect inhibition of GnRH synthesis at the hypothalamic level, which resulted in reduction of serum levels of LH that lead to suppression of testosterone production in the testis of mice.MC-LR may be a GnRH toxin that would disrupt the reproductive system of mice.

  17. Thoughts on the so-called 'radius-capitellum axis'

    International Nuclear Information System (INIS)

    Schild, H.; Mueller, H.A.; Wagner, H.; Baetz, W.; Mainz Univ.

    1982-01-01

    We have studied 438 patients radiologically in order to observe the so-called 'radius-capitellum axis'. In about a quarter of people with normal elbows the axis passes lateral to the middle portion of the capitellum, so that even when there is marked deviation, there is no certainty that the humero-radial joint is abnormal. Deviation of the axis can be caused by changes in the shape of the capitellum or of the radius, or by distension of the capsule of the elbow joint, or by various changes in muscular pull. (orig.) [de

  18. Thoughts on the so-called radius-capitellum axis

    Energy Technology Data Exchange (ETDEWEB)

    Schild, H; Mueller, H A; Wagner, H; Baetz, W

    1982-02-01

    We have studied 438 patients radiologically in order to observe the so-called 'radius-capitellum axis'. In about a quarter of people with normal elbows the axis passes lateral to the middle portion of the capitellum, so that even when there is marked deviation, there is no certainty that the humero-radial joint is abnormal. Deviation of the axis can be caused by changes in the shape of the capitellum or of the radius, or by distension of the capsule of the elbow joint, or by various changes in muscular pull.

  19. [Localization and registration of the hinge axis in black Africans].

    Science.gov (United States)

    Assi, K D; N'Guessan, K S; N'Dindin, C; Bamba, A

    2003-06-01

    The study of the cinematic method using "SAM" and "Quick Axis of FAG" added to mandibular condyle palpation for the hinge axis limited points, show that the Black Africans mandibular condyle rotation axis position is higher (3.5 mm) and backer (2 mm) than the Caucasians. The axial points are located to between 11 and 12 mm in front of the tragus and between 7 and 8 mm below on the perpendicular line to the furrow defining the tragus superior side to the Ectocanthus.

  20. Dosimetric Consistency of Co-60 Teletherapy Unit- a ten years Study.

    Science.gov (United States)

    Baba, Misba H; Mohib-Ul-Haq, M; Khan, Aijaz A

    2013-01-01

    The goal of the Radiation standards and Dosimetry is to ensure that the output of the Teletherapy Unit is within ±2% of the stated one and the output of the treatment dose calculation methods are within ±5%. In the present paper, we studied the dosimetry of Cobalt-60 (Co-60) Teletherapy unit at Sher-I-Kashmir Institute of Medical Sciences (SKIMS) for last 10 years. Radioactivity is the phenomenon of disintegration of unstable nuclides called radionuclides. Among these radionuclides, Cobalt-60, incorporated in Telecobalt Unit, is commonly used in therapeutic treatment of cancer. Cobalt-60 being unstable decays continuously into Ni-60 with half life of 5.27 years thereby resulting in the decrease in its activity, hence dose rate (output). It is, therefore, mandatory to measure the dose rate of the Cobalt-60 source regularly so that the patient receives the same dose every time as prescribed by the radiation oncologist. The under dosage may lead to unsatisfactory treatment of cancer and over dosage may cause radiation hazards. Our study emphasizes the consistency between actual output and output obtained using decay method. The methodology involved in the present study is the calculations of actual dose rate of Co-60 Teletherapy Unit by two techniques i.e. Source to Surface Distance (SSD) and Source to Axis Distance (SAD), used for the External Beam Radiotherapy, of various cancers, using the standard methods. Thereby, a year wise comparison has been made between average actual dosimetric output (dose rate) and the average expected output values (obtained by using decay method for Co-60.). The present study shows that there is a consistency in the average output (dose rate) obtained by the actual dosimetry values and the expected output values obtained using decay method. The values obtained by actual dosimetry are within ±2% of the expected values. The results thus obtained in a year wise comparison of average output by actual dosimetry done regularly as a part of

  1. Patient-specific IMRT verification using independent fluence-based dose calculation software: experimental benchmarking and initial clinical experience

    International Nuclear Information System (INIS)

    Georg, Dietmar; Stock, Markus; Kroupa, Bernhard; Olofsson, Joergen; Nyholm, Tufve; Ahnesjoe, Anders; Karlsson, Mikael

    2007-01-01

    Experimental methods are commonly used for patient-specific intensity-modulated radiotherapy (IMRT) verification. The purpose of this study was to investigate the accuracy and performance of independent dose calculation software (denoted as 'MUV' (monitor unit verification)) for patient-specific quality assurance (QA). 52 patients receiving step-and-shoot IMRT were considered. IMRT plans were recalculated by the treatment planning systems (TPS) in a dedicated QA phantom, in which an experimental 1D and 2D verification (0.3 cm 3 ionization chamber; films) was performed. Additionally, an independent dose calculation was performed. The fluence-based algorithm of MUV accounts for collimator transmission, rounded leaf ends, tongue-and-groove effect, backscatter to the monitor chamber and scatter from the flattening filter. The dose calculation utilizes a pencil beam model based on a beam quality index. DICOM RT files from patient plans, exported from the TPS, were directly used as patient-specific input data in MUV. For composite IMRT plans, average deviations in the high dose region between ionization chamber measurements and point dose calculations performed with the TPS and MUV were 1.6 ± 1.2% and 0.5 ± 1.1% (1 S.D.). The dose deviations between MUV and TPS slightly depended on the distance from the isocentre position. For individual intensity-modulated beams (total 367), an average deviation of 1.1 ± 2.9% was determined between calculations performed with the TPS and with MUV, with maximum deviations up to 14%. However, absolute dose deviations were mostly less than 3 cGy. Based on the current results, we aim to apply a confidence limit of 3% (with respect to the prescribed dose) or 6 cGy for routine IMRT verification. For off-axis points at distances larger than 5 cm and for low dose regions, we consider 5% dose deviation or 10 cGy acceptable. The time needed for an independent calculation compares very favourably with the net time for an experimental approach

  2. Preliminary tests of a high speed vertical axis windmill model

    Energy Technology Data Exchange (ETDEWEB)

    South, P; Rangi, R S

    1971-01-01

    This report discusses a fixed-pitch vertical axis windmill that combines the inherent simplicity of this type of machine with a high aerodynamic efficiency and a high relative velocity. A three-bladed rotor was selected as the basic design, having constant chord symmetric airfoil blades configured in a catenary curve such that the rotor diameter is equal to the rotor height. In wind tunnel tests using a 30 inch scale model, it was found that once this rotor was given a very low rotational speed, it picked up speed and ran at a rotor tip velocity/wind speed ratio greater than 1. The number of blades was varied in the testing. A maximum power coefficient of 0.67 was achieved at 17 ft/s wind speed at a tip speed/wind speed ratio of 7.25 for a 2-bladed rotor. Increasing the number of blades above 3 did not result in higher power. The rotor could operate in gusts which double the mean wind velocity. Examination of Reynolds number effects, and taking into account the scale of the model, it was concluded that a full-scale windmill could run at lower velocity ratios than those predicted by the model tests, and that it could self-start under no-load conditions if the cut-in rpm are at least half the rpm for maximum power at the prevailing wind speed. Preliminary estimates show that a 15 ft diameter windmill of this design, designed to operate with a safety factor of 2.5 up to a maximum wind speed of 60 ft/s, would weigh ca 150 lb and could be marketed for ca $60.00, excluding the driven unit, if sufficient quantities were produced to make tooling costs negligible. Similarly, a 30 ft windmill would weigh ca 1000 lb and cost ca $400.00. 2 refs., 6 figs.

  3. Effective doses in paediatric radiology

    International Nuclear Information System (INIS)

    Iacob, Olga; Diaconescu, Cornelia; Roca, Antoaneta

    2001-01-01

    Because of their longer life expectancy, the risk of late manifestations of detrimental radiation effects is greater in children than in adults and, consequently, paediatric radiology gives ground for more concern regarding radiation protection than radiology of adults. The purpose of our study is to assess in terms of effective doses the magnitude of paediatric patient exposure during conventional X-ray examinations, selected for their high frequency or their relatively high doses to the patient. Effective doses have been derived from measurements of dose-area product (DAP) carried out on over 900 patients undergoing X-ray examinations, in five paediatric units. The conversion coefficients for estimating effective doses are those calculated by the NRPB using Monte-Carlo technique on a series of 5 mathematical phantoms representing 0, 1, 5, 10 and 15 year old children. The annual frequency of X-ray examinations necessary for collective dose calculation are those reported in our last national study on medical exposure, conducted in 1995. The annual effective doses from all medical examinations for the average paediatric patient are as follows: 1.05 mSv for 0 year old, 0.98 mSv for 1 year old, 0.53 mSv for 5 year old, 0.65 mSv for 10 year old and 0.70 mSv for 15 year old. The resulting annual collective effective dose was evaluated at 625 man Sv with the largest contribution of pelvis and hip examinations (34%). The annual collective effective associated with paediatric radiology in Romania represent 5% of the annual value resulting from all diagnostic radiology. Examination of the chest is by far the most frequent procedure for children, accounting for about 60 per cent of all annually performed X-ray conventional examinations. Knowledge of real level of patient dose is an essential component of quality assurance programs in paediatric radiology. (authors)

  4. What is correct: equivalent dose or dose equivalent

    International Nuclear Information System (INIS)

    Franic, Z.

    1994-01-01

    In Croatian language some physical quantities in radiation protection dosimetry have not precise names. Consequently, in practice either terms in English or mathematical formulas are used. The situation is even worse since the Croatian language only a limited number of textbooks, reference books and other papers are available. This paper compares the concept of ''dose equivalent'' as outlined in International Commission on Radiological Protection (ICRP) recommendations No. 26 and newest, conceptually different concept of ''equivalent dose'' which is introduced in ICRP 60. It was found out that Croatian terminology is both not uniform and unprecise. For the term ''dose equivalent'' was, under influence of Russian and Serbian languages, often used as term ''equivalent dose'' even from the point of view of ICRP 26 recommendations, which was not justified. Unfortunately, even now, in Croatia the legal unit still ''dose equivalent'' defined as in ICRP 26, but the term used for it is ''equivalent dose''. Therefore, in Croatian legislation a modified set of quantities introduced in ICRP 60, should be incorporated as soon as possible

  5. Infinite slab-shield dose calculations

    International Nuclear Information System (INIS)

    Russell, G.J.

    1989-01-01

    I calculated neutron and gamma-ray equivalent doses leaking through a variety of infinite (laminate) slab-shields. In the shield computations, I used, as the incident neutron spectrum, the leakage spectrum (<20 MeV) calculated for the LANSCE tungsten production target at 90 degree to the target axis. The shield thickness was fixed at 60 cm. The results of the shield calculations show a minimum in the total leakage equivalent dose if the shield is 40-45 cm of iron followed by 20-15 cm of borated (5% B) polyethylene. High-performance shields can be attained by using multiple laminations. The calculated dose at the shield surface is very dependent on shield material. 4 refs., 4 figs., 1 tab

  6. Evaluation of iodide deficiency in the lactating rat and pup using a biologically based dose response (BBDR) Model***

    Science.gov (United States)

    A biologically-based dose response (BBDR) model for the hypothalamic-pituitary thyroid (HPT) axis in the lactating rat and nursing pup was developed to describe the perturbations caused by iodide deficiency on the 1-IPT axis. Model calibrations, carried out by adjusting key model...

  7. Evaluation of iodide deficiency in the lactating rat and pup using a biologically based dose-response model

    Science.gov (United States)

    A biologically-based dose response (BBDR) model for the hypothalamic-pituitary thyroid (BPT) axis in the lactating rat and nursing pup was developed to describe the perturbations caused by iodide deficiency on the HPT axis. Model calibrations, carried out by adjusting key model p...

  8. Hand Dose in Nuclear Medicine Staff Members

    International Nuclear Information System (INIS)

    Taha, T.M.; Shahein, A.Y.; Hassan, R.

    2009-01-01

    Measurement of the hand dose during preparation and injection of radiopharmaceuticals is useful in the assessment of the extremity doses received by nuclear medicine personnel. Hand radiation doses to the occupational workers that handling 99m Tc-labeled compounds, 131 I for diagnostic in nuclear medicine were measured by thermoluminescence dosimetry. A convenient method is to use a TLD ring dosimeter for measuring doses of the diagnostic units of different nuclear medicine facilities . Their doses were reported in millisieverts that accumulated in 4 weeks. The radiation doses to the hands of nuclear medicine staff at the hospitals under study were measured. The maximum expected annual dose to the extremities appeared to be less than the annual limit (500 mSv/y) because all of these workers are on rotation and do not constantly handle radioactivity throughout the year

  9. A Method for Modeling of Floating Vertical Axis Wind Turbine

    DEFF Research Database (Denmark)

    Wang, Kai; Hansen, Martin Otto Laver; Moan, Torgeir

    2013-01-01

    It is of interest to investigate the potential advantages of floating vertical axis wind turbine (FVAWT) due to its economical installation and maintenance. A novel 5MW vertical axis wind turbine concept with a Darrieus rotor mounted on a semi-submersible support structure is proposed in this paper....... In order to assess the technical and economic feasibility of this novel concept, a comprehensive simulation tool for modeling of the floating vertical axis wind turbine is needed. This work presents the development of a coupled method for modeling of the dynamics of a floating vertical axis wind turbine....... This integrated dynamic model takes into account the wind inflow, aerodynamics, hydrodynamics, structural dynamics (wind turbine, floating platform and the mooring lines) and a generator control. This approach calculates dynamic equilibrium at each time step and takes account of the interaction between the rotor...

  10. design and implementation of a microcontroller based dual axis

    African Journals Online (AJOL)

    user

    In this paper, an efficient microcontroller-based dual axis solar radiation tracker which can be used to align a single photovoltaic (PV) ... replaced them with wind turbine generating stations. ... tracker which has both horizontal and vertical axle.

  11. The effects of lateral head tilt on ocular astigmatic axis

    Directory of Open Access Journals (Sweden)

    Hamid Fesharaki

    2014-01-01

    Conclusion: Any minimal angle of head tilt may cause erroneous measurement of astigmatic axis and should be avoided during refraction. One cannot rely on the compensatory function of ocular counter-torsion during the refraction.

  12. Particle orbit analysis for LHD helical axis configurations

    International Nuclear Information System (INIS)

    Guasp, J.; Yamazaki, K.; Motojima, O.

    1993-04-01

    Fast ion orbits for helical magnetic axis configurations in LHD (Large Helical Device) are analyzed and compared with the standard circular axis case. Boundaries between passing and helically trapped particle regions show clear differences: in the non-planar axis case the helically trapped region spreads, near the magnetic axis, over a much wider band across the 90deg pitch angle value and shows a very marked asymmetry. The locally trapped particle region is also wider than in the standard case. The differences in the loss cone boundaries of the two cases are rather small, however, the effects of re-entering criteria are very important in both cases. On the contrary, effects of finite coil size are not significant. (author)

  13. Off-axis vortex breakdown in a shallow whirlpool.

    Science.gov (United States)

    Herrada, Miguel A; Shtern, Vladimir N; López-Herrera, José María

    2013-06-01

    The off-axis emergence of vortex breakdown (VB) is revealed. The steady axisymmetric flow in a vertical sealed cylinder, which is partially filled with water and the rest is filled with air, is driven by the rotating bottom disk. The numerical simulations show that VB can emerge away from the rotation axis, interface, and walls. As the rotation intensifies, VB first develops in the water region. If the water height is less (larger) than nearly one half of the cylinder radius, VB emerges off (on) the axis. As the rotation further increases, the off-axis VB ring touches the interface and then a thin countercirculation layer develops in the air flow above the water VB domain. This two-fluid VB ring shrinks (it even disappears in a very shallow whirlpool) as the interface approaches the bottom disk.

  14. Helical-axis stellarators with noninterlocking planar coils

    International Nuclear Information System (INIS)

    Reiman, A.; Boozer, A.

    1983-08-01

    The properties of helical axis stellarator fields generated by unlinked, planar coils are described. It is shown that such fields can have a magnetic well and large rotational transform, implying large equilibrium and stability beta limits

  15. Helical-axis stellarators with noninterlocking planar coils

    Energy Technology Data Exchange (ETDEWEB)

    Reiman, A.; Boozer, A.

    1983-08-01

    The properties of helical axis stellarator fields generated by unlinked, planar coils are described. It is shown that such fields can have a magnetic well and large rotational transform, implying large equilibrium and stability beta limits.

  16. Design of a Three-Axis Machine Tool Module

    National Research Council Canada - National Science Library

    Childers, Marshal

    2003-01-01

    This report documents the design improvement process of the components in a tool module for a three-axis machine tool, which occurred during the period of March-April 2002 in support of a critical U.S...

  17. Dual Axis Controller for Extreme Environments, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The Dual Axis Controller for Extreme Environments (DACEE) addresses a critical need of NASA's future exploration plans to investigate extreme environments within our...

  18. Three-Axis Gasless Sounding Rocket Payload Attitude Control

    Data.gov (United States)

    National Aeronautics and Space Administration — Gas released by current sounding rocket payload attitude control systems (ACS) has the potential to interfere with some types of science instruments. A single-axis...

  19. Computational Modeling of Hypothalamic-Pituitary-Gonadal Axis to Predict Adaptive Responses in Female Fathead Minnows Exposed to an Aromatase Inhibitor

    Science.gov (United States)

    Exposure to endocrine disrupting chemicals can affect reproduction and development in both humans and wildlife. We are developing a mechanistic computational model of the hypothalamic-pituitary-gonadal (HPG) axis in female fathead minnows to predict dose response and time-course...

  20. Microbiota-gut-brain axis and the central nervous system

    OpenAIRE

    Zhu, Xiqun; Han, Yong; Du, Jing; Liu, Renzhong; Jin, Ketao; Yi, Wei

    2017-01-01

    The gut and brain form the gut-brain axis through bidirectional nervous, endocrine, and immune communications. Changes in one of the organs will affect the other organs. Disorders in the composition and quantity of gut microorganisms can affect both the enteric nervous system and the central nervous system (CNS), thereby indicating the existence of a microbiota-gut-brain axis. Due to the intricate interactions between the gut and the brain, gut symbiotic microorganisms are closely associated ...

  1. Dose prescription in boron neutron capture therapy

    International Nuclear Information System (INIS)

    Gupta, N.M.S.; Gahbauer, R.A.; Blue, T.E.; Wambersie, A.

    1994-01-01

    The purpose of this paper is to address some aspects of the many considerations that need to go into a dose prescription in boron neutron capture therapy (BNCT) for brain tumors; and to describe some methods to incorporate knowledge from animal studies and other experiments into the process of dose prescription. Previously, an algorithm to estimate the normal tissue tolerance to mixed high and low linear energy transfer radiations in BNCT was proposed. The authors have developed mathematical formulations and computational methods to represent this algorithm. Generalized models to fit the central axis dose rate components for an epithermal neutron field were also developed. These formulations and beam fitting models were programmed into spreadsheets to simulate two treatment techniques which are expected to be used in BNCT: a two-field bilateral scheme and a single-field treatment scheme. Parameters in these spreadsheets can be varied to represent the fractionation scheme used, the 10 B microdistribution in normal tissue, and the ratio of 10 B in tumor to normal tissue. Most of these factors have to be determined for a given neutron field and 10 B compound combination from large animal studies. The spreadsheets have been programmed to integrate all of the treatment-related information and calculate the location along the central axis where the normal tissue tolerance is exceeded first. This information is then used to compute the maximum treatment time allowable and the maximum tumor dose that may be delivered for a given BNCT treatment. The effect of different treatment variables on the treatment time and tumor dose has been shown to be very significant. It has also been shown that the location of D max shifts significantly, depending on some of the treatment variables-mainly the fractionation scheme used. These results further emphasize the fact that dose prescription in BNCT is very complicated and nonintuitive. 11 refs., 6 figs., 3 tabs

  2. Validation of GPU based TomoTherapy dose calculation engine.

    Science.gov (United States)

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

    2012-04-01

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

  3. Terapêutica com doses profiláticas de sulfato ferroso como medida de intervenção no combate à carência de ferro em crianças atendidas em unidades básicas de saúde Treatment with prophylactic doses of ferrous sulphate in the fight against iron deficiency in children attended in basis health units

    Directory of Open Access Journals (Sweden)

    Marco A. A. Torres

    1994-12-01

    Full Text Available Objetivou-se testar a terapêutica com doses profiláticas de sulfato ferroso no combate à anemia carencial ferropriva, em 620 crianças de 4 a 36 meses de idade, atendidas em duas unidades de saúde do Município de São Paulo, Brasil. As crianças foram submetidas a coleta de sangue para dosagem de hemoglobina. Em seguida, foi prescrito dosagem de 12 mg/dia de ferro elementar, por 30 dias. Observou-se que 25% dos menores de 6 meses apresentaram níveis de hemoglobina inferiores a 11,0 g/dl. As maiores ocorrências de anemia foram detectadas entre os 9 e 23 meses de idade (50,0%. Decorrido o prazo, apenas 37,4% das crianças com anemia e 52,4% das não anêmicas retornaram para reavaliação. Das 299 que foram reavaliadas, somente 157 (52,5% receberam a medicação corretamente. A freqüência de hemoglobinas inferiores a 9,5 g/dl caiu de 17,1% no início, para 8,1% ao final da intervenção. Por outro lado, o percentual de crianças com hemoglobinas superiores a 12,0 g/dl subiu de 13,4%, para 33,4%. As que receberam a suplementação férrica de forma correta registraram queda nos índices de anemia sensivelmente maior que a observada naquelas suplementadas de forma incorreta. Concluiu-se que a terapêutica com doses profiláticas de sulfato ferroso, apesar de se mostrar eficiente na recuperação dos níveis de hemoglobina, apresenta sérios entraves do ponto de vista operacional.The efficacy of medical prophylaxis in the fight against iron deficiency anemia in 620 children aged from four to thirty-six months, attended in two health units of the municipality of S. Paulo, Brazil, was tested. First, the children's blood was tested for hemoglobin level and eletrophoresis. Then they received daily doses of iron sulphate in the form of drops, corresponding to 12 mg/ day of elementary iron, over a 30-day period. Afterwaeds, they were asked to return for re-evaluation. Twenty-five percent of children under 6 months presented hemoglobin levels under

  4. The role of the crystal rotation axis in experimental three- and four-beam phase determination

    International Nuclear Information System (INIS)

    Post, B.; Gong, P.P.; Kern, L.; Ladell, J.

    1986-01-01

    The geometry of four-beam diffraction and procedures for generating it systematically are described. These utilize relatively simple Renninger-type experimental arrangements. The four reciprocal-lattice points involved in each four-beam interaction are located at the corners of rectangles or symmetrical trapezoids in reciprocal space. One of the sides, or a diagonal, of each such quadrilateral serves as the axis of the azimuthal rotation of the crystal. Experiments designed to compare the relative merits of different types of rotation axes have been carried out. It is found that axes of twofold (or higher) symmetry provide advantages over alternate arrangements for experimental phase determination. Four-beam interations are then generated systematically and in greater abundance than in all other n-beam interations combined (n > 2). Such interactions usually provide stronger phase indications than comparable three-beam interaction. The experiments also showed that, although the phase of an 'invariant' quartet is clearly invariant to the choice of unit-cell origin, it is not necessarily invariant to a change of rotation axis from one two-fold axis to another. (orig.)

  5. [Correlation between the lower first permanent molar axis and the premature loss of temporary molars].

    Science.gov (United States)

    Petcu, Ana; Maxim, A; Haba, Danisia

    2009-01-01

    The aim of our study was to determine the impact of premature loss of temporary molars upon the longitudinal axis of the first permanent molar. The study sample was formed by 94 orthopanthomografies of child patients with premature loss of lower temporary molars (first or second) after clinical eruption of the first permanent molar. All panoramic radiographs have been realized with the same panoramic unit with 1.4% magnification coefficient and were analyzed using a standardized technique of tracing the images of teeth and bone on matte acetate paper. It was evaluated the angle between longitudinal axis of first permanent lower molar and occlusal plane. It was observed that premature loss of lower second deciduous molar modifies greater the vertical axis of first permanent molar (between 61 degrees and 79 degrees) then premature loss of first lower primary molar. This is perhaps because the loss of space in the case of premature exfoliation of first primary molar is due more to distal drift of canine then mesial drift of molars. The drift to mesial of first permanent molar is more accentuated proportional with the age at which appeared premature loss and so it is loss of leeway space.

  6. Real-time quantitative phase reconstruction in off-axis digital holography using multiplexing.

    Science.gov (United States)

    Girshovitz, Pinhas; Shaked, Natan T

    2014-04-15

    We present a new approach for obtaining significant speedup in the digital processing of extracting unwrapped phase profiles from off-axis digital holograms. The new technique digitally multiplexes two orthogonal off-axis holograms, where the digital reconstruction, including spatial filtering and two-dimensional phase unwrapping on a decreased number of pixels, can be performed on both holograms together, without redundant operations. Using this technique, we were able to reconstruct, for the first time to our knowledge, unwrapped phase profiles from off-axis holograms with 1 megapixel in more than 30 frames per second using a standard single-core personal computer on a MATLAB platform, without using graphic-processing-unit programming or parallel computing. This new technique is important for real-time quantitative visualization and measurements of highly dynamic samples and is applicable for a wide range of applications, including rapid biological cell imaging and real-time nondestructive testing. After comparing the speedups obtained by the new technique for holograms of various sizes, we present experimental results of real-time quantitative phase visualization of cells flowing rapidly through a microchannel.

  7. Modelling lateral beam quality variations in pencil kernel based photon dose calculations

    International Nuclear Information System (INIS)

    Nyholm, T; Olofsson, J; Ahnesjoe, A; Karlsson, M

    2006-01-01

    Standard treatment machines for external radiotherapy are designed to yield flat dose distributions at a representative treatment depth. The common method to reach this goal is to use a flattening filter to decrease the fluence in the centre of the beam. A side effect of this filtering is that the average energy of the beam is generally lower at a distance from the central axis, a phenomenon commonly referred to as off-axis softening. The off-axis softening results in a relative change in beam quality that is almost independent of machine brand and model. Central axis dose calculations using pencil beam kernels show no drastic loss in accuracy when the off-axis beam quality variations are neglected. However, for dose calculated at off-axis positions the effect should be considered, otherwise errors of several per cent can be introduced. This work proposes a method to explicitly include the effect of off-axis softening in pencil kernel based photon dose calculations for arbitrary positions in a radiation field. Variations of pencil kernel values are modelled through a generic relation between half value layer (HVL) thickness and off-axis position for standard treatment machines. The pencil kernel integration for dose calculation is performed through sampling of energy fluence and beam quality in sectors of concentric circles around the calculation point. The method is fully based on generic data and therefore does not require any specific measurements for characterization of the off-axis softening effect, provided that the machine performance is in agreement with the assumed HVL variations. The model is verified versus profile measurements at different depths and through a model self-consistency check, using the dose calculation model to estimate HVL values at off-axis positions. A comparison between calculated and measured profiles at different depths showed a maximum relative error of 4% without explicit modelling of off-axis softening. The maximum relative error

  8. Performance characteristics of a Vertical Axis Wind Turbine (VAWT) under transient conditions

    OpenAIRE

    Colley, Gareth; Mishra, Rakesh

    2011-01-01

    The present work investigates the performance characteristics of a novel Vertical Axis Wind Turbine (VAWT) for use in the urban environment. Here the performance of the wind turbine has been analyzed experimentally using a full scale prototype measuring 2.0m diameter and 1.0m in height. The turbine was located at the exit of a 0.6m x 0.6m wind tunnel section and was subjected to a jet flow. The performance output from the turbine has been obtained using a torque transducer unit which provides...

  9. Self-starting aerodynamics analysis of vertical axis wind turbine

    Directory of Open Access Journals (Sweden)

    Jianyang Zhu

    2015-12-01

    Full Text Available Vertical axis wind turbine is a special type of wind-force electric generator which is capable of working in the complicated wind environment. The self-starting aerodynamics is one of the most important considerations for this kind of turbine. This article aims at providing a systematic synthesis on the self-starting aerodynamic characteristics of vertical axis wind turbine based on the numerical analysis approach. First, the physical model of vertical axis wind turbine and its parameter definitions are presented. Secondary, the interaction model between the vertical axis wind turbine and fluid is developed by using the weak coupling approach; the numerical data of this model are then compared with the wind tunnel experimental data to show its feasibility. Third, the effects of solidity and fixed pitch angle on the self-starting aerodynamic characteristics of the vertical axis wind turbine are analyzed systematically. Finally, the quantification effects of the solidity and fixed pitch angle on the self-starting performance of the turbine can be obtained. The analysis in this study will provide straightforward physical insight into the self-starting aerodynamic characteristics of vertical axis wind turbine.

  10. Energy Efficient Hybrid Dual Axis Solar Tracking System

    Directory of Open Access Journals (Sweden)

    Rashid Ahammed Ferdaus

    2014-01-01

    Full Text Available This paper describes the design and implementation of an energy efficient solar tracking system from a normal mechanical single axis to a hybrid dual axis. For optimizing the solar tracking mechanism electromechanical systems were evolved through implementation of different evolutional algorithms and methodologies. To present the tracker, a hybrid dual-axis solar tracking system is designed, built, and tested based on both the solar map and light sensor based continuous tracking mechanism. These light sensors also compare the darkness and cloudy and sunny conditions assisting daily tracking. The designed tracker can track sun’s apparent position at different months and seasons; thereby the electrical controlling device requires a real time clock device for guiding the tracking system in seeking solar position for the seasonal motion. So the combination of both of these tracking mechanisms made the designed tracker a hybrid one. The power gain and system power consumption are compared with a static and continuous dual axis solar tracking system. It is found that power gain of hybrid dual axis solar tracking system is almost equal to continuous dual axis solar tracking system, whereas the power saved in system operation by the hybrid tracker is 44.44% compared to the continuous tracking system.

  11. Major and minor axis kinematics of 22 ellipticals

    International Nuclear Information System (INIS)

    Franx, M.; Illingworth, G.; Heckman, T.

    1989-01-01

    Rotation curves and velocity dispersion profiles have been determined for the major and the minor axes of 22 elliptical galaxies. Rotation was detected in all but one galaxy, even though the sample was biased toward round ellipticals. Minor axis rotation larger than major axis rotation was measured in two galaxies, NGC 4406 and NGC 7507. Roughly 10 percent of ellipticals may show large minor axis velocities relative to those on the major axis. A simple model is used to derive a rotational axis from the observed minor and major axis velocities to a typical accuracy of 6 deg. The rotational and photometric minor axes aligned to better than 10 deg for 60 percent of the sample, implying that the direction of the angular momentum is related to the orientation of the figure of the galaxy. IC 1459 has a kinematically distinct core with its angular momentum opposite to the angular momentum of the outer parts, and NGC 4406 has a core with its angular momentum perpendicular to that of the outer parts. 46 refs

  12. Optic axis-driven new horizons for hyperbolic metamaterials

    Directory of Open Access Journals (Sweden)

    Boardman Allan D.

    2015-01-01

    Full Text Available The broad assertion here is that the current hyperbolic metamaterial world is only partially served by investigations that incorporate only some limited version of anisotropy. Even modest deviations of the optic axis from the main propagation axis lead to new phase shifts, which not only compete with those created by absorption but end up dominating them. Some progress has been attempted in the literature by introducing the terms “asymmetric hyperbolic media”, but it appears that this kind of asymmetry only involves an optic axis at an angle to the interface of a uniaxial crystal. From a device point of view, many new prospects should appear and the outcomes of the investigations presented here yield a new general theory. It is emphasised that the orientation of the optic axis is a significant determinant in the resulting optical properties. Whereas for conventional anisotropic waveguides homogeneous propagating waves occur over a limited range of angular dispositions of the optic axis it is shown that for a hyperbolic guide a critical angular setting exists, above which the guided waves are always homogeneous. This has significant implications for metawaveguide designs. The resulting structures are more tolerant to optic axis misalignment.

  13. Perioperative management of the hypothalamic-pituitary-adrenal axis in patients with pituitary adenomas: an Australasian survey.

    Science.gov (United States)

    Joseph, S P; Ho, J T; Doogue, M P; Burt, M G

    2012-10-01

    There is limited consensus regarding optimal glucocorticoid administration for pituitary surgery to prevent a potential adrenal crisis. To assess the investigation and management of the hypothalamic-pituitary-adrenal (HPA) axis in patients undergoing trans-sphenoidal hypophysectomy in Australasia. A questionnaire was sent to one endocrinologist at each of 18 centres performing pituitary surgery in Australasia. Using hypothetical case vignettes, respondents were asked to describe their investigation and management of the HPA axis for a patient with a: non-functioning macroadenoma and intact HPA axis, non-functioning macroadenoma and HPA deficiency and growth hormone secreting microadenoma undergoing trans-sphenoidal hypophysectomy. Responses were received from all 18 centres. Seventeen centres assess the HPA axis preoperatively by measuring early morning cortisol or a short synacthen test. Preoperative evaluation of the HPA status influenced glucocorticoid prescription by 10 centres, including 2/18 who would not prescribe perioperative glucocorticoids for a patient with a macroadenoma and an intact HPA axis. Tumour size influenced glucocorticoid prescribing patterns at 7/18 centres who prescribe a lower dose or no glucocorticoids for a patient with a microadenoma. Choice of investigations for definitive postoperative assessment of the HPA axis varied with eight centres requesting an insulin tolerance test, four centres a 250 µg short synacthen test and six centres requesting other tests. There is wide variability in the investigation and management of perioperative glucocorticoid requirements for patients undergoing pituitary surgery in Australasia. This may reflect limited evidence to define optimal management and that further well-designed studies are needed. © 2011 The Authors; Internal Medicine Journal © 2011 Royal Australasian College of Physicians.

  14. Internal radiation dose in diagnostic nuclear medicine

    Energy Technology Data Exchange (ETDEWEB)

    Roedler, H D; Kaul, A; Hine, G J

    1978-01-01

    Absorbed dose values per unit administered activity for the most frequently used radipharmaceuticals and methods were calculated according to the MIRD concept or compiled from literature and were tabulated in conventional as well as in the SI-units recently introduced. The data are given for critical or investigated organs, ovaries, testes and red bone marrow. Where available, dose values for newborns, infants and children are included. Additionally, mean values of administered activity are listed. The manner in which to estimate the radiation dose to the patient is to multiply the tabulated dose values per unit administered activity with the corresponding mean or the actually administered activity. The methods are arranged in correlation with the following nuclear medical subspecialities: 1. Endocrinology 2. Neurology, 3. Osteomyology, 4. Gastroenterology, 5. Nephrology, 6. Pulmonology, 7. Hematology, 8. Cardiology/Angiology.

  15. From personnel dose to personal dose

    International Nuclear Information System (INIS)

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

    1985-01-01

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

  16. Concepts of collective dose in radiological protection

    International Nuclear Information System (INIS)

    Lindell, B.

    1985-01-01

    The collective dose (S) is the product of the number of individuals exposed and their average radiation dose. ''Radiation dose'' is usually taken to be the effective dose equivalent (Hsub(E)) as defined by the ICRP. The unit of the collective dose is then the man.sievert (man.Sv). The following four applications of the collective dose are the most common: (a) in the assessment of the highest per caput dose rate in the future from a continued practice which exposes some critical group or the population as a whole to radiation; (b) in the limitation of present radiation sources, if it is believed that additional sources in the future may add to the per caput dose in a population so that it might reach unacceptable levels unless all sources are controlled at an early stage; (c) as an input to justification assessments, indicating the total detriment from a certain practice; and (d) as an input to optimization assessments as the basis for costing detriment in differential cost-benefit analyses of protection arrangements. It is sometimes said that the collective dose is a useful quantity only if the assumption of a non-threshold, linear dose-response relation is valid. This assumption is not always necessary. Applications (a) and (b) are possible without any assumption on the dose-response relationship at very low doses. Only applications (c) and (d) require the assumption of a non-threshold, linear dose-response relation. Some hesitation in using the collective dose originates in distrust in the biological assumptions implied by uses (c) and (d), but also in lack of confidence in the meaningfulness of collective doses that have been derived by adding dose contributions over very long time periods. However, none of the four applications (a) - (d) is by necessity related to extreme time scales. That problem mainly arises in the assessment of radioactive waste repositories

  17. MCNPX simulation of proton dose distribution in homogeneous and CT phantoms

    International Nuclear Information System (INIS)

    Lee, C.C.; Lee, Y.J.; Tung, C.J.; Cheng, H.W.; Chao, T.C.

    2014-01-01

    A dose simulation system was constructed based on the MCNPX Monte Carlo package to simulate proton dose distribution in homogeneous and CT phantoms. Conversion from Hounsfield unit of a patient CT image set to material information necessary for Monte Carlo simulation is based on Schneider's approach. In order to validate this simulation system, inter-comparison of depth dose distributions among those obtained from the MCNPX, GEANT4 and FLUKA codes for a 160 MeV monoenergetic proton beam incident normally on the surface of a homogeneous water phantom was performed. For dose validation within the CT phantom, direct comparison with measurement is infeasible. Instead, this study took the approach to indirectly compare the 50% ranges (R 50% ) along the central axis by our system to the NIST CSDA ranges for beams with 160 and 115 MeV energies. Comparison result within the homogeneous phantom shows good agreement. Differences of simulated R 50% among the three codes are less than 1 mm. For results within the CT phantom, the MCNPX simulated water equivalent R eq,50% are compatible with the CSDA water equivalent ranges from the NIST database with differences of 0.7 and 4.1 mm for 160 and 115 MeV beams, respectively. - Highlights: ► Proton dose simulation based on the MCNPX 2.6.0 in homogeneous and CT phantoms. ► CT number (HU) conversion to electron density based on Schneider's approach. ► Good agreement among MCNPX, GEANT4 and FLUKA codes in a homogeneous water phantom. ► Water equivalent R 50 in CT phantoms are compatible to those of NIST database

  18. Circularly Polarized Microwave Antenna Element with Very Low Off-Axis Cross-Polarization

    Science.gov (United States)

    Greem. David; DuToit, Cornelis

    2013-01-01

    The goal of this work was to improve off-axis cross-polarization performance and ease of assembly of a circularly polarized microwave antenna element. To ease assembly, the initial design requirement of Hexweb support for the internal circuit part, as well as the radiating disks, was eliminated. There is a need for different plating techniques to improve soldering. It was also desirable to change the design to eliminate soldering as well as the need to use the Hexweb support. Thus, a technique was developed to build the feed without using solder, solving the lathing and soldering issue. Internal parts were strengthened by adding curvature to eliminate Hexweb support, and in the process, the new geometries of the internal parts opened the way for improving the off-axis cross-polarization performance as well. The radiating disks curvatures were increased for increased strength, but it was found that this also improved crosspolarization. Optimization of the curvatures leads to very low off-axis cross-polarization. The feed circuit was curved into a cylinder for improved strength, eliminating Hexweb support. An aperture coupling feed mechanism eliminated the need for feed pins to the disks, which would have required soldering. The aperture coupling technique also improves cross-polarization performance by effectively exciting the radiating disks very close to the antenna s central axis of symmetry. Because of the shape of the parts, it allowed for an all-aluminum design bolted together and assembled with no solder needed. The advantage of a solderless design is that the reliability is higher, with no single-point failure (solder), and no need for special plating techniques in order to solder the unit together. The shapes (curved or round) make for a more robust build without extra support materials, as well as improved offaxis cross-polarization.

  19. Automated positioning dual-axis solar tracking system with precision elevation and azimuth angle control

    International Nuclear Information System (INIS)

    Sidek, M.H.M.; Azis, N.; Hasan, W.Z.W.; Ab Kadir, M.Z.A.; Shafie, S.; Radzi, M.A.M.

    2017-01-01

    This paper presents a study on an automated positioning open-loop dual-axis solar tracking system. The solar tracker was designed and fabricated using standard cylindrical aluminium hollow and Polyuthrene (PE). The control system of the solar tracker was governed by Micro Controller Unit (MCU) with auxiliary devices which includes encoder and Global Positioning System (GPS). The sun path trajectory algorithm utilizing the astronomical equation and GPS information was also embedded in the system. The power generation performance of the dual-axis solar tracking system was compared with the fixed-tilted Photovoltaic (PV) system. It is found that the solar tracker is able to position itself automatically based on sun path trajectory algorithm with an accuracy of ±0.5°. The embedded Proportional Integral Derivative (PID) positioning system improves the tracking of elevation and azimuth angles with minimum energy consumption. It is reveals that the proposed solar tracker is able generate 26.9% and 12.8% higher power than fixed-tilted PV system on a clear and heavy overcast conditions respectively. Overall, the open-loop dual-axis solar tracker can be deployed automatically at any location on the earth with minimal configurations and is suitable for mobile solar tracking system. - Highlights: • Self-positioning dual-axis solar tracking system. • Precise control of elevation and azimuth angle. • Sun path trajectory based on astronomical equation and GPS. • Can achieve up to 26.9% higher power than fixed-tilted PV system under clear weather condition.

  20. Dose assessment at Bikini Atoll

    International Nuclear Information System (INIS)

    Robison, W.L.; Phillips, W.A.; Colsher, C.S.

    1977-01-01

    Bikini Atoll is one of two sites in the northern Marshall Islands that was used by the United States as testing grounds for the nuclear weapons program from 1946 to 1958. In 1969 a general cleanup began at Bikini Atoll. Subsistence crops, coconut and Pandanus fruit, were planted on Bikini and Eneu Islands, and housing was constructed on Bikini Island. A second phase of housing was planned for the interior of Bikini Island. Preliminary data indicated that external gamma doses in the interior of the island might be higher than in other parts of the island. Therefore, to select a second site for housing on the island with minimum external exposure, a survey of Bikini Atoll was conducted in June 1975. External gamma measurements were made on Bikini and Eneu Islands, and soil and vegetations samples collected to evaluate the potential doses via terrestrial food chains and inhalation. Estimates of potential dose via the marine food chain were based upon data collected on previous trips to the atoll. The terrestrial pathway contributes the greater percentage, external gamma exposure contributes the next highest, and inhalation and marine pathways contribute minor fractions of the total whole body and bone marrow doses. The radionuclides contributing the major fraction of the dose are 90 Sr and 137 Cs. All living patterns involving Bikini Island exceed federal guidelines for 30-yr population doses. The Eneu Island living pattern leads to doses that are slightly less than federal guidelines. All patterns evaluated for Bikini Atoll lead to higher doses than those on the southern islands at Enewetak Atoll

  1. Age-dependent conversion coefficients for organ doses and effective doses for external neutron irradiation

    International Nuclear Information System (INIS)

    Nishizaki, Chihiro; Endo, Akira; Takahashi, Fumiaki

    2006-06-01

    To utilize dose assessment of the public for external neutron irradiation, conversion coefficients of absorbed doses of organs and effective doses were calculated using the numerical simulation technique for six different ages (adult, 15, 10, 5 and 1 years and newborn), which represent the member of the public. Calculations were performed using six age-specific anthropomorphic phantoms and a Monte Carlo radiation transport code for two irradiation geometries, anterior-posterior and rotational geometries, for 20 incident energies from thermal to 20 MeV. Effective doses defined by the 1990 Recommendation of ICRP were calculated from the absorbed doses in 21 organs. The calculated results were tabulated in the form of absorbed doses and effective doses per unit neutron fluence. The calculated conversion coefficients are used for dose assessment of the public around nuclear facilities and accelerator facilities. (author)

  2. Design Of Single-Axis And Dual-Axis Solar Tracking Systems Protected Against High Wind Speeds

    Directory of Open Access Journals (Sweden)

    Mai Salaheldin Elsherbiny

    2017-09-01

    Full Text Available Solar energy is rapidly gaining ground as an important mean of expanding renewable energy use. Solar tracking is employed in order to maximize collected solar radiation by a photovoltaic panel. In this paper we present a prototype for Automatic solar tracker that is designed using Arduino UNO with Wind sensor to Cease Wind effect on panels if wind speed exceeds certain threshold. The Proposed solar tracker tracks the location of the sun anywhere in any time by calculating the position of the sun. For producing the maximum amount of solar energy a solar panel must always be perpendicular to the source of light. Because the sun motion plane varies daily and during the day it moves from east to west one needs two axis tracking to follow the suns position. Maximum possible power is collected when two axis tracking is done. However two axis tracking is relatively costly and complex. A compromise between maximum power collection and system simplicity is obtained by single axis tracking where the plane North south axis is fixed while the east west motion is accomplished. This work deals with the design of both single and two axis tracking systems. Automatic trackers is also compared to Fixed one in terms of Energy generated Efficiency Cost and System reliability.

  3. Effect of dosimeter type for commissioning small photon beams on calculated dose distribution in stereotactic radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    García-Garduño, O. A., E-mail: oagarciag@innn.edu.mx, E-mail: amanda.garcia.g@gmail.com [Laboratorio de Física Médica, Instituto Nacional de Neurología y Neurocirugía, Mexico City 14269, México and Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Instituto Politécnico Nacional, Legaria 694, México City 11500, México (Mexico); Rodríguez-Ponce, M. [Departamento de Biofísica, Instituto Nacional de Cancerología, Mexico City 14080, México (Mexico); Gamboa-deBuen, I. [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City 04510 (Mexico); Rodríguez-Villafuerte, M. [Instituto de Física, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City 04510 (Mexico); Galván de la Cruz, O. O. [Laboratorio de Física Médica, Instituto Nacional de Neurología y Neurocirugía, Mexico City 14269, México (Mexico); and others

    2014-09-15

    Purpose: To assess the impact of the detector used to commission small photon beams on the calculated dose distribution in stereotactic radiosurgery (SRS). Methods: In this study, six types of detectors were used to characterize small photon beams: three diodes [a silicon stereotactic field diode SFD, a silicon diode SRS, and a silicon diode E], an ionization chamber CC01, and two types of radiochromic film models EBT and EBT2. These detectors were used to characterize circular collimated beams that were generated by a Novalis linear accelerator. This study was conducted in two parts. First, the following dosimetric data, which are of particular interest in SRS, were compared for the different detectors: the total scatter factor (TSF), the tissue phantom ratios (TPRs), and the off-axis ratios (OARs). Second, the commissioned data sets were incorporated into the treatment planning system (TPS) to compare the calculated dose distributions and the dose volume histograms (DVHs) that were obtained using the different detectors. Results: The TSFs data measured by all of the detectors were in good agreement with each other within the respective statistical uncertainties: two exceptions, where the data were systematically below those obtained for the other detectors, were the CC01 results for all of the circular collimators and the EBT2 film results for circular collimators with diameters below 10.0 mm. The OAR results obtained for all of the detectors were in excellent agreement for all of the circular collimators. This observation was supported by the gamma-index test. The largest difference in the TPR data was found for the 4.0 mm circular collimator, followed by the 10.0 and 20.0 mm circular collimators. The results for the calculated dose distributions showed that all of the detectors passed the gamma-index test at 100% for the 3 mm/3% criteria. The aforementioned observation was true regardless of the size of the calculation grid for all of the circular collimators

  4. Radiographic film: surface dose extrapolation techniques

    International Nuclear Information System (INIS)

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

    2004-01-01

    Full text: Assessment of surface dose delivered from radiotherapy x-ray beams for optimal results should be performed both inside and outside the prescribed treatment fields An extrapolation technique can be used with radiographic film to perform surface dose assessment for open field high energy x-ray beams. This can produce an accurate 2 dimensional map of surface dose if required. Results have shown that surface % dose can be estimated within ±3% of parallel plate ionisation chamber results with radiographic film using a series of film layers to produce an extrapolated result. Extrapolated percentage dose assessment for 10cm, 20cmand 30cm square fields was estimated to be 15% ± 2%, 29% ± 3% and 38% ± 3% at the central axis and relatively uniform across the treatment field. Corresponding parallel plate ionisation chamber measurement are 16%, 27% and 37% respectively. Surface doses are also measured outside the treatment field which are mainly due to scattered electron contamination. To achieve this result, film calibration curves must be irradiated to similar x-ray field sizes as the experimental film to minimize quantitative variations in film optical density caused by varying x-ray spectrum with field size. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

  5. Surface dose extrapolation measurements with radiographic film

    International Nuclear Information System (INIS)

    Butson, Martin J; Cheung Tsang; Yu, Peter K N; Currie, Michael

    2004-01-01

    Assessment of surface dose delivered from radiotherapy x-ray beams for optimal results should be performed both inside and outside the prescribed treatment fields. An extrapolation technique can be used with radiographic film to perform surface dose assessment for open field high energy x-ray beams. This can produce an accurate two-dimensional map of surface dose if required. Results have shown that the surface percentage dose can be estimated within ±3% of parallel plate ionization chamber results with radiographic film using a series of film layers to produce an extrapolated result. Extrapolated percentage dose assessment for 10 cm, 20 cm and 30 cm square fields was estimated to be 15% ± 2%, 29% ± 3% and 38% ± 3% at the central axis and relatively uniform across the treatment field. The corresponding parallel plate ionization chamber measurements are 16%, 27% and 37%, respectively. Surface doses are also measured outside the treatment field which are mainly due to scattered electron contamination. To achieve this result, film calibration curves must be irradiated to similar x-ray field sizes as the experimental film to minimize quantitative variations in film optical density caused by varying x-ray spectrum with field size. (note)

  6. Radiochromic film as a radiotherapy surface-dose detector

    International Nuclear Information System (INIS)

    Butson, M.J.; Metcalfe, P.E.; Wollongong Univ., NSW; Mathur, J.N.

    1996-01-01

    Radiochromic film is shown to be a useful surface-dose detector for radiotherapy x-ray beams. Central-axis percentage surface-dose results as measured by Gafchromic film for a 6 MVp x-ray beam produced by a Varian 2100C Linac at 100 cm SSD are 16%, 25%, 35%, 41% for 10, 20, 30 and 40 cm square field sizes, respectively. Using a simple, uniform light source and a CCD camera connected to an image analysis system, quantitative 3D surface doses are accurately attainable in real time as either numerical data, a black-and-white image or a colour-enhanced image. (Author)

  7. Postnatal development of the atlas and axis: CT study

    International Nuclear Information System (INIS)

    Byun, Sung Su; Kim, Hyung Jin; Lim, Myung Kwan; Kim, Won Hong; Jeon, Yong Sun; Kim, Jeong Ho; Kim, Sung Tae

    2003-01-01

    To evaluate normal postnatal development of the atlas and axis by means of CT scanning. We prospectively analyzed CT scans of the developing atlas and axis of 200 normal children aged less than 14, investigating the CT appearance of these regions with particular attenuation to two synchondroses related to the atlas and four synchondroses and one ossification center related to the axis. Fusion varying was categorized as either low (grade1-5) or high (grade4-5), according to the varying degrees of fusion at each synchondrosis of ossification center. Neurocentral synchondrosis of the atlas was low grade in all children less than five, and high grade in all aged nine or more, while posterior synchondrosis of the atlas was low grade in 97% of children less than three and high grade in 99% aged three or more. As for the axis, neurocentral synchondrosis was low grade in all children less than three, and high grade in 97% of children aged five or more. PS of the axis was low grade in both children less than 6 months, and high grade in all aged two years or more. Dentocentral synchondrosis of the axis was low grade in 93% of children less than three and high grade in 96% of those aged at least five. Intradental axial synchondrosis was high grade in all children. Fusion of the terminal ossicle with the remainder of the dens was low in all children less than five and high in 97% of those aged nine of more. CT can help determine the parameters of normal postnatal development of the atlas and axis. A knowledge of normal ossification patterns of these regions may help provide an understanding of developmental anomalies and also help prevent confusion with fractures

  8. SI units in biomedical dosimetry

    International Nuclear Information System (INIS)

    Liden, K.

    1975-01-01

    The International commission on radiation units and measurements (ICRU), during the period from 1953 to 1962 presented its definitions of the quantities absorbed dose, exposure, activity, and dose equivalent and the corresponding special units the rad, the roentgen, the curie, and the rem. At the same time an international practical system of units was developed, Le Systeme International d'Unites (SI). It was adopted by the 11th Conference Generale des Poids et Mesures (CGPM) in 1960 and is now officially introduced in almost all countries. The general implementation of the SI means difficulties for the future use of the special radiation units, because the numerical factors involved prevent their adoption as SI units. In view of this, and after having sampled the opinion in the radiological field, the ICRU prepared a Statement on Units in July, 1974 which was forwarded to the Comite International des Poids et Mesures (CIPM) and its Comite Consultatif des Unites (CCU) for consideration. As a result of this statement the CIPM has now proposed, that the 15rh CGPM adopt special names for two SI units, namely the becquerel, symbol Bq, for the unit of activity of radionuclides equal to the reciprocal second, s 1- , and the gray, symbol Gy, for the unit of absorbed dose equal to the joule per kilogram, J/kg. The 15th CGPM will consider this matter in May, 1975. (author)

  9. The Protective and Curative Role of Selenium and Vitamin E Against Disorders Induced by Gamma Radiation on The Hypophysis Thyroid Axis in Rats

    International Nuclear Information System (INIS)

    Abdel-Fattah, K.I.; Abou-Safi, H.M.; Abdel-Khalek, L.G.; Mehany, N.L.; Ragab, M.T.

    2003-01-01

    This work aimed to investigate the protective and curative potency of both selenium and vitamin E on the hypophysis-thyroid axis hormones of rats exposed to a collective dose of 4 Gy whole body gamma irradiation. Rats were divided into five groups; control, drenched with antioxidants (2.5 mcg selenium and 1.5 mg vitamin E/100 GB wt), exposed to fractionated dose (4 Gy) of gamma radiation (0.5 Gy twice weekly for one month), drenched with antioxidants before each dose of irradiation and a group of rats supplied with antioxidants both before each dose of irradiation and for one month after the last dose of irradiation. Results obtained showed that administration of the two antioxidants both before irradiation doses and for one month after the last dose of irradiation showed the best effects on plasma levels of T 3 , T 4 , and TSH. SO, it could be concluded that oral administration of both selenium and vitamin E before and after exposure to fractionated whole body gamma irradiation showed protective and curative effects on the hypophysis-thyroid axis hormones in rats. Depending on the obtained results and in order to protect patients from gamma irradiation hazard, we recommend the use of these two antioxidants (selenium and vitamin E) before and after the exposure to the therapeutic doses of gamma radiation

  10. Dose sculpting with generalized equivalent uniform dose

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  11. On uncertainties in definition of dose equivalent

    International Nuclear Information System (INIS)

    Oda, Keiji

    1995-01-01

    The author has entertained always the doubt that in a neutron field, if the measured value of the absorbed dose with a tissue equivalent ionization chamber is 1.02±0.01 mGy, may the dose equivalent be taken as 10.2±0.1 mSv. Should it be 10.2 or 11, but the author considers it is 10 or 20. Even if effort is exerted for the precision measurement of absorbed dose, if the coefficient being multiplied to it is not precise, it is meaningless. [Absorbed dose] x [Radiation quality fctor] = [Dose equivalent] seems peculiar. How accurately can dose equivalent be evaluated ? The descriptions related to uncertainties in the publications of ICRU and ICRP are introduced, which are related to radiation quality factor, the accuracy of measuring dose equivalent and so on. Dose equivalent shows the criterion for the degree of risk, or it is considered only as a controlling quantity. The description in the ICRU report 1973 related to dose equivalent and its unit is cited. It was concluded that dose equivalent can be considered only as the absorbed dose being multiplied by a dimensionless factor. The author presented the questions. (K.I.)

  12. Mechanical impedance of the sitting human body in single-axis compared to multi-axis whole-body vibration exposure.

    Science.gov (United States)

    Holmlund, P; Lundström, R

    2001-01-01

    The study was aimed to investigate the mechanical impedance of the sitting human body and to compare data obtained in laboratory single-axis investigations with multi-axis data from in vehicle measurements. The experiments were performed in a laboratory for single-axis measurements. The multi-axis exposure was generated with an eight-seat minibus where the rear seats had been replaced with a rigid one. The subjects in the multi-axis experiment all participated in the single-axis experiments. There are quite a few investigations in the literature describing the human response to single-axis exposure. The response from the human body can be expected to be affected by multi-axis input in a different way than from a single-axis exposure. The present knowledge of the effect of multiple axis exposure is very limited. The measurements were performed using a specially designed force and accelerometer plate. This plate was placed between the subject and the hard seat. Outcome shows a clear difference between mechanical impedance for multi-axis exposure compared to single-axis. This is especially clear in the x-direction where the difference is very large. The conclusion is that it seems unlikely that single-axis mechanical impedance data can be directly transferred to a multi-axis environment. This is due to the force cross-talk between different directions.

  13. Measurement Axis Searching Model for Terrestrial Laser Scans Registration

    Directory of Open Access Journals (Sweden)

    Shaoxing Hu

    2016-01-01

    Full Text Available Nowadays, terrestrial Lidar scans can cover rather a large area; the point densities are strongly varied because of the line-of-sight measurement principle in potential overlaps with scans taken from different viewpoints. Most of the traditional methods focus on registration algorithm and ignore searching model. Sometimes the traditional methods are directly used to align two point clouds; a large critically unsolved problem of the large biases will be created in areas distant from the overlaps while the local overlaps are often aligned well. So a novel measurement axis searching model (MASM has been proposed in this paper. The method includes four steps: (1 the principal axis fitting, (2 the measurement axis generation, (3 low-high-precision search, and (4 result generation. The principal axis gives an orientation to the point cloud; the search scope is limited by the measurement axis. The point cloud orientation can be adjusted gradually until the achievement of the global optimum using low- and high-precision search. We perform some experiments with simulated point clouds and real terrestrial laser scans. The results of simulated point clouds have shown the processing steps of our method, and the results of real terrestrial laser scans have shown the sensitivity of the approach with respect to the indoor and outdoor scenes.

  14. Ankle-foot orthosis bending axis influences running mechanics.

    Science.gov (United States)

    Russell Esposito, Elizabeth; Ranz, Ellyn C; Schmidtbauer, Kelly A; Neptune, Richard R; Wilken, Jason M

    2017-07-01

    Passive-dynamic ankle-foot orthoses (AFOs) are commonly prescribed to improve locomotion for people with lower limb musculoskeletal weakness. The clinical prescription and design process are typically qualitative and based on observational assessment and experience. Prior work examining the effect of AFO design characteristics generally excludes higher impact activities such as running, providing clinicians and researchers limited information to guide the development of objective prescription guidelines. The proximal location of the bending axis may directly influence energy storage and return and resulting running mechanics. The purpose of this study was to determine if the location of an AFO's bending axis influences running mechanics. Marker and force data were recorded as 12 participants with lower extremity weakness ran overground while wearing a passive-dynamic AFO with posterior struts manufactured with central (middle) and off-centered (high and low) bending axes. Lower extremity joint angles, moments, powers, and ground reaction forces were calculated and compared between limbs and across bending axis conditions. Bending axis produced relatively small but significant changes. Ankle range of motion increased as the bending axis shifted distally (pbenefits during running, although individual preference and physical ability should also be considered. Published by Elsevier B.V.

  15. Surface dose measurements in and out of field. Implications for breast radiotherapy with megavoltage photon beams

    Energy Technology Data Exchange (ETDEWEB)

    Lonski, Peta; Kron, Tomas [Peter MacCallum Cancer Centre, Melbourne (Australia); RMIT Univ., Melbourne (Australia); Ramachandran, Prabhakar; Franich, Rick [Peter MacCallum Cancer Centre, Melbourne (Australia)

    2017-07-01

    This study examines the difference in surface dose between flat and flattening filter free (FFF) photon beams in the context of breast radiotherapy. The surface dose was measured for 6 MV, 6 MV FFF, 10 MV, 10 MV FFF and 18 MV photon beams using a thin window ionisation chamber for various field sizes. Profiles were acquired to ascertain the change in surface dose off-axis. Out-of-field measurements were included in a clinically representative half beam block tangential breast field. In the field centres of FFF beams the surface dose was found to be increased for small fields and decreased for large fields compared to flat beams. For FFF beams, surface dose was found to decrease off-axis and resulted in lower surface dose out-of-field compared to flat beams.

  16. Radiation leakage dose from Elekta electron collimation system.

    Science.gov (United States)

    Pitcher, Garrett M; Hogstrom, Kenneth R; Carver, Robert L

    2016-09-08

    This study provided baseline data required for a greater project, whose objective was to design a new Elekta electron collimation system having significantly lighter electron applicators with equally low out-of field leakage dose. Specifically, off-axis dose profiles for the electron collimation system of our uniquely configured Elekta Infinity accelerator with the MLCi2 treatment head were measured and calculated for two primary purposes: 1) to evaluate and document the out-of-field leakage dose in the patient plane and 2) to validate the dose distributions calculated using a BEAMnrc Monte Carlo (MC) model for out-of-field dose profiles. Off-axis dose profiles were measured in a water phantom at 100 cm SSD for 1 and 2 cm depths along the in-plane, cross-plane, and both diagonal axes using a cylindrical ionization chamber with the 10 × 10 and 20 × 20 cm2 applicators and 7, 13, and 20 MeV beams. Dose distributions were calculated using a previously developed BEAMnrc MC model of the Elekta Infinity accelerator for the same beam energies and applicator sizes and compared with measurements. Measured results showed that the in-field beam flatness met our acceptance criteria (± 3% on major and ±4% on diagonal axes) and that out-of-field mean and maximum percent leakage doses in the patient plane met acceptance criteria as specified by the International Electrotechnical Commission (IEC). Cross-plane out-of-field dose profiles showed greater leakage dose than in-plane profiles, attributed to the curved edges of the upper X-ray jaws and multileaf collimator. Mean leakage doses increased with beam energy, being 0.93% and 0.85% of maximum central axis dose for the 10 × 10 and 20 × 20 cm2 applicators, respectively, at 20 MeV. MC calculations predicted the measured dose to within 0.1% in most profiles outside the radiation field; however, excluding model-ing of nontrimmer applicator components led to calculations exceeding measured data by as much as 0.2% for some regions

  17. Gestational 3,3',4,4',5-pentachlorobiphenyl (PCB 126) exposure disrupts fetoplacental unit: Fetal thyroid-cytokines dysfunction.

    Science.gov (United States)

    Ahmed, R G; El-Gareib, A W; Shaker, H M

    2018-01-01

    Exposure to polychlorinated biphenyls (PCBs) is related to several endocrine disorders. This study examined the effect of maternal exposure of 3,3',4,4',5-pentachlorobiphenyl (PCB 126) on the fetoplacental unit and fetal thyroid-cytokine axis during the pregnancy. Pregnant albino rats received PCB 126 (20 or 40μg/kgb.wt.) by oral gavage from gestation day (GD) 1 to 20. Potential effects of PCB 126 were evaluated by following the histopathological changes in the placenta by Haematoxylin and Eosin (H&E) stain and measuring the maternofetal thyroid axis (ELIZA), maternofetal body weight, and fetal growth markers (ELIZA), and cytokines (ELIZA) at embryonic day (ED) 20. Placental tissues of both treated groups showed hyperemia, hemorrhage, degeneration and apoptosis in labyrinth layer and spiral artery at GD 20. Both administrations of PCB 126 elevated serum thyrotropin (TSH) concentration, and decreased free thyroxine (FT4) and free triiodothyronine (FT3) concentrations, resulting in a maternofetal hypothyroidism. The presence of hypothyroidism increased fetal serum concentration of transforming growth factor-β (TGF-β), leptin (LEP), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and decreased the fetal serum insulin growth factor-I (IGF-I), IGF-II, insulin, adiponectin (ADP), and growth hormone (GH) in both treated groups at ED 20. However, the increase in resistin (RETN) and interferon-γ (IFN-γ) was non-significant in low-dose group and highly significant in high-dose group. Simultaneously, the reduction in body weight of the dams and fetuses was observed in both PCB 126 groups of examined day with respect to the control group. The maternal PCB 126 distorted the fetoplacental unit might disrupt the fetal thyroid-cytokines axis and prenatal development. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Empirical equations for the representation of depth dose data for computerized treatment planning

    International Nuclear Information System (INIS)

    Kornelsen, R.O.; Young, M.E.J.

    1975-01-01

    Equations of the form P = 100 (1 - (1 - exp ( -d/Q) )sup(M)) and TAR = S (1 - (1 - exp (-d/Q) ) sup(M) ) have been used to represent the variation of central axis percentage depth dose P or tissue-air ratio (TAR) with depth d below the dose maximum. These equations were originally developed for the representation of cobalt 60 depth dose data but have also been fitted to the central axis depth dose data published in the British Journal of Radiology Supplement 11, for radiations ranging in energy from 1.5 mm Cu HVT to 8 MV. Values of the constants Q and M for standard field sizes are presented together with an estimate of the goodness of fit in each case. Two different approaches have been used in determining the dose at points other than those on the central axis. In the simpler method, used for rotation techniques, the off-axis ratio (OAR) was calculated from the equation: OAR = k 1 + (1 - k 1 ) 1/(1 + exp (k 2 (x - 0.5 w)))] where x is the off-axis distance, w the field width at the depth and k 1 and k 2 are constants. In the more accurate method, used for fixed field techniques, different equations were used within the main beam, within the geometrical penumbra and outside the beam. (author)

  19. Field test report of the Department of Energy's 100-kW vertical axis wind turbine

    Science.gov (United States)

    Nellums, R. O.

    1985-02-01

    Three second generation Darrieus type vertical axis wind turbines of approximately 120 kW capacity per unit were installed in 1980-1981. Through March 1984, over 9000 hours of operation had been accumulated, including 6600 hours of operation on the unit installed in Bushland, Texas. The turbines were heavily instrumented and have yielded a large amount of test data. Test results of this program, including aerodynamic, structural, drive train, and economic data are presented. Among the most favorable results were an aerodynamic peak performance coefficient of 0.41; fundamental structural integrity requiring few repairs and no major component replacements as of March 1984; and an average prototype fabrication cost of approximately $970 per peak kilowatt of output. A review of potential design improvements is presented.

  20. Variations in depth-dose data between open and wedge fields for 4-MV x-rays

    International Nuclear Information System (INIS)

    Sewchand, W.; Khan, F.M.; Williamson, J.

    1978-01-01

    Central-axis depth-dose data for 4-MV x rays, including tissue-maximum ratios, were measured for wedge fields. Comparison with corresponding open-field data revealed differences in magnitude which increased with depth, field size, and wedge thickness. However, phantom scatter correction factors for the wedge fields differed less than 1% from corresponding open-field factors. The differences in central-axis percent depth doses between the two types of fields indicate beam hardening by the wedge filter. This study also implies that the derivation of tissue-maximum ratios from central-axis percent depth is as valid for wedge as for open fields

  1. Pocket total dose meter

    International Nuclear Information System (INIS)

    Brackenbush, L.W.; Endres, G.W.R.

    1984-10-01

    Laboratory measurements have demonstrated that it is possible to simultaneously measure absorbed dose and dose equivalent using a single tissue equivalent proportional counter. Small, pocket sized instruments are being developed to determine dose equivalent as the worker is exposed to mixed field radiation. This paper describes the electronic circuitry and computer algorithms used to determine dose equivalent in these devices

  2. On dose distribution comparison

    International Nuclear Information System (INIS)

    Jiang, Steve B; Sharp, Greg C; Neicu, Toni; Berbeco, Ross I; Flampouri, Stella; Bortfeld, Thomas

    2006-01-01

    In radiotherapy practice, one often needs to compare two dose distributions. Especially with the wide clinical implementation of intensity-modulated radiation therapy, software tools for quantitative dose (or fluence) distribution comparison are required for patient-specific quality assurance. Dose distribution comparison is not a trivial task since it has to be performed in both dose and spatial domains in order to be clinically relevant. Each of the existing comparison methods has its own strengths and weaknesses and there is room for improvement. In this work, we developed a general framework for comparing dose distributions. Using a new concept called maximum allowed dose difference (MADD), the comparison in both dose and spatial domains can be performed entirely in the dose domain. Formulae for calculating MADD values for various comparison methods, such as composite analysis and gamma index, have been derived. For convenience in clinical practice, a new measure called normalized dose difference (NDD) has also been proposed, which is the dose difference at a point scaled by the ratio of MADD to the predetermined dose acceptance tolerance. Unlike the simple dose difference test, NDD works in both low and high dose gradient regions because it considers both dose and spatial acceptance tolerances through MADD. The new method has been applied to a test case and a clinical example. It was found that the new method combines the merits of the existing methods (accurate, simple, clinically intuitive and insensitive to dose grid size) and can easily be implemented into any dose/intensity comparison tool

  3. Derivation of dose conversion factors for tritium

    Energy Technology Data Exchange (ETDEWEB)

    Killough, G. G.

    1982-03-01

    For a given intake mode (ingestion, inhalation, absorption through the skin), a dose conversion factor (DCF) is the committed dose equivalent to a specified organ of an individual per unit intake of a radionuclide. One also may consider the effective dose commitment per unit intake, which is a weighted average of organ-specific DCFs, with weights proportional to risks associated with stochastic radiation-induced fatal health effects, as defined by Publication 26 of the International Commission on Radiological Protection (ICRP). This report derives and tabulates organ-specific dose conversion factors and the effective dose commitment per unit intake of tritium. These factors are based on a steady-state model of hydrogen in the tissues of ICRP's Reference Man (ICRP Publication 23) and equilibrium of specific activities between body water and other tissues. The results differ by 27 to 33% from the estimate on which ICRP Publication 30 recommendations are based. The report also examines a dynamic model of tritium retention in body water, mineral bone, and two compartments representing organically-bound hydrogen. This model is compared with data from human subjects who were observed for extended periods. The manner of combining the dose conversion factors with measured or model-predicted levels of contamination in man's exposure media (air, drinking water, soil moisture) to estimate dose rate to an individual is briefly discussed.

  4. Derivation of dose conversion factors for tritium

    International Nuclear Information System (INIS)

    Killough, G.G.

    1982-03-01

    For a given intake mode (ingestion, inhalation, absorption through the skin), a dose conversion factor (DCF) is the committed dose equivalent to a specified organ of an individual per unit intake of a radionuclide. One also may consider the effective dose commitment per unit intake, which is a weighted average of organ-specific DCFs, with weights proportional to risks associated with stochastic radiation-induced fatal health effects, as defined by Publication 26 of the International Commission on Radiological Protection (ICRP). This report derives and tabulates organ-specific dose conversion factors and the effective dose commitment per unit intake of tritium. These factors are based on a steady-state model of hydrogen in the tissues of ICRP's Reference Man (ICRP Publication 23) and equilibrium of specific activities between body water and other tissues. The results differ by 27 to 33% from the estimate on which ICRP Publication 30 recommendations are based. The report also examines a dynamic model of tritium retention in body water, mineral bone, and two compartments representing organically-bound hydrogen. This model is compared with data from human subjects who were observed for extended periods. The manner of combining the dose conversion factors with measured or model-predicted levels of contamination in man's exposure media (air, drinking water, soil moisture) to estimate dose rate to an individual is briefly discussed

  5. Role of Met Axis in Head and Neck Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yiru, E-mail: xuyiru@umich.edu; Fisher, Gary J., E-mail: xuyiru@umich.edu [Department of Dermatology, University of Michigan, Ann Arbor, MI 48109 (United States)

    2013-11-26

    Head and neck cancer is the sixth most common type of cancer worldwide. Despite advances in aggressive multidisciplinary treatments, the 5-year survival rate for this dreadful disease is only 50%, mostly due to high rate of recurrence and early involvement of regional lymph nodes and subsequent metastasis. Understanding the molecular mechanisms responsible for invasion and metastasis is one of the most pressing goals in the field of head and neck cancer. Met, also known as hepatocyte growth factor receptor (HGFR), is a member of the receptor protein tyrosine kinase (RPTK) family. There is compelling evidence that Met axis is dysregulated and plays important roles in tumorigenesis, progression, metastasis, angiogenesis, and drug resistance in head and neck cancer. We describe in this review current understanding of Met axis in head and neck cancer biology and development of therapeutic inhibitors targeting Met axis.

  6. Subquadratic medial-axis approximation in $\\mathbb{R}^3$

    Directory of Open Access Journals (Sweden)

    Christian Scheffer

    2015-09-01

    Full Text Available We present an algorithm that approximates the medial axis of a smooth manifold in $\\mathbb{R}^3$ which is given by a sufficiently dense point sample. The resulting, non-discrete approximation is shown to converge to the medial axis as the sampling density approaches infinity. While all previous algorithms guaranteeing convergence have a running time quadratic in the size $n$ of the point sample, we achieve a running time of at most $\\mathcal{O}(n\\log^3 n$. While there is no subquadratic upper bound on the output complexity of previous algorithms for non-discrete medial axis approximation, the output of our algorithm is guaranteed to be of linear size.

  7. Small Vertical Axis Wind Turbines: aerodynamics and starting behavior

    Directory of Open Access Journals (Sweden)

    Horia DUMITRESCU

    2013-12-01

    Full Text Available In urban areas the wind is very turbulent and unstable with fast changes in direction andvelocity. In these environments, the use of small vertical axis wind turbines (VAWT becomesincreasingly attractive due to several advantages over horizontal axis wind turbines (HAWT.However, such designs have received much less attention than the more common propeller-typedesigns and the understanding of same aspects of their operation remains, to this day, incomplete.This is particularly true of their starting characteristics. Indeed, same authors heuristically maintainthat they cannot start without external assistance. This paper reviews the cause of the inability of thelow solidity fixed pitch vertical axis wind turbines to self-start, and investigates the way ofovercoming this draw back.

  8. Off-axis and inline electron holography: Experimental comparison

    International Nuclear Information System (INIS)

    Latychevskaia, Tatiana; Formanek, Petr; Koch, C.T.; Lubk, Axel

    2010-01-01

    Electron holography is a very powerful technique for mapping static electric and magnetic potentials down to atomic resolution. While electron holography is commonly considered synonymous with its off-axis variant in the high energy electron microscopy community, inline electron holography is widely applied in low-energy electron microscopy, where the realization of the off-axis setup is still an experimental challenge. This paper demonstrates that both inline and off-axis holography may be used to recover amplitude and phase shift of the very same object, in our example latex spheres of 90 and 200 nm in diameter, producing very similar results, provided the object does not charge under the electron beam.

  9. Vertical axis wind turbines: a survey and bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Abramovich, H

    1987-01-01

    The stimulus for the development of modern, big wind turbines has been the world-wide oil crisis during the seventies. Although the horizontal axis wind turbines (HAWT) was the most popular type of wind turbine the Darrieus vertical axis wind turbine (VAWT) has been recognized as a machine with competitive economic potential. The state of the art of the VAWT is reviewed. The wind turbine carrying the name of Darrieus was first proposed by the French inventor in 1925. His original patent covered a range of vertical-axis configurations but the term 'Darrieus' is now generally associated with the curved-blade geometry. In 1966 two researchers at the Canadian NRC again raised the idea of both the straight and curved-blade versions of the Darrieus VAWT.

  10. Calibration of three-axis magnetometers with differential evolution algorithm

    International Nuclear Information System (INIS)

    Pang, Hongfeng; Zhang, Qi; Wang, Wei; Wang, Junya; Li, Ji; Luo, Shitu; Wan, Chengbiao; Chen, Dixiang; Pan, Mengchun; Luo, Feilu

    2013-01-01

    The accuracy of three-axis magnetometers is influenced by different scale and bias of each axis and nonorthogonality between axes. One limitation of traditional iteration methods is that initial parameters influence the calibration, thus leading to the local optimal or wrong results. In this paper, a new method is proposed to calibrate three-axis magnetometers. To employ this method, a nonmagnetic rotation platform, a proton magnetometer, a DM-050 three-axis magnetometer and the differential evolution (DE) algorithm are used. The performance of this calibration method is analyzed with simulation and experiment. In simulation, the calibration results of DE, unscented Kalman filter (UKF), recursive least squares (RLS) and genetic algorithm (GA) are compared. RMS error using DE is least, which is reduced from 81.233 nT to 1.567 nT. Experimental results show that comparing with UKF, RLS and GA, the DE algorithm has not only the least calibration error but also the best robustness. After calibration, RMS error is reduced from 68.914 nT to 2.919 nT. In addition, the DE algorithm is not sensitive to initial parameters, which is an important advantage compared with traditional iteration algorithms. The proposed algorithm can avoid the troublesome procedure to select suitable initial parameters, thus it can improve the calibration performance of three-axis magnetometers. - Highlights: • The calibration results and robustness of UKF, GA, RLS and DE algorithm are analyzed. • Calibration error of DE is the least in simulation and experiment. • Comparing with traditional calibration algorithms, DE is not sensitive to initial parameters. • It can improve the calibration performance of three-axis magnetometers

  11. Research on Parameter Design of Multi - axis Hydrostatic Transmission Vehicle

    Directory of Open Access Journals (Sweden)

    Zhao Liang

    2017-01-01

    Full Text Available In order to obtain reasonable parameters in the design of driving system of multi-axis hydrostatic transmission vehicle, the working principle of single-side drive of hydrostatic transmission vehicle is introduced. The matching and control of engine and hydraulic pump are analyzed. According to the driving equation of vehicle, The driving force required for driving system is determined, and the parameters of hydraulic motor, hydraulic pump, system working pressure and braking system are designed and calculated, which provides the parameter design for driving system of multi-axis hydrostatic transmission Reliable theoretical basis.

  12. Microbiota-gut-brain axis and the central nervous system.

    Science.gov (United States)

    Zhu, Xiqun; Han, Yong; Du, Jing; Liu, Renzhong; Jin, Ketao; Yi, Wei

    2017-08-08

    The gut and brain form the gut-brain axis through bidirectional nervous, endocrine, and immune communications. Changes in one of the organs will affect the other organs. Disorders in the composition and quantity of gut microorganisms can affect both the enteric nervous system and the central nervous system (CNS), thereby indicating the existence of a microbiota-gut-brain axis. Due to the intricate interactions between the gut and the brain, gut symbiotic microorganisms are closely associated with various CNS diseases, such as Parkinson's disease, Alzheimer's disease, schizophrenia, and multiple sclerosis. In this paper, we will review the latest advances of studies on the correlation between gut microorganisms and CNS functions & diseases.

  13. Three axis vector atomic magnetometer utilizing polarimetric technique

    Energy Technology Data Exchange (ETDEWEB)

    Pradhan, Swarupananda, E-mail: spradhan@barc.gov.in, E-mail: pradhans75@gmail.com [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 400085, India and Homi Bhabha National Institute, Department of Atomic Energy, Mumbai 400094 (India)

    2016-09-15

    The three axis vector magnetic field measurement based on the interaction of a single elliptically polarized light beam with an atomic system is described. The magnetic field direction dependent atomic responses are extracted by the polarimetric detection in combination with laser frequency modulation and magnetic field modulation techniques. The magnetometer geometry offers additional critical requirements like compact size and large dynamic range for space application. Further, the three axis magnetic field is measured using only the reflected signal (one polarization component) from the polarimeter and thus can be easily expanded to make spatial array of detectors and/or high sensitivity field gradient measurement as required for biomedical application.

  14. Interpretation and quality of the tilted axis cranking approximation

    International Nuclear Information System (INIS)

    Frauendorf, S.; Meng, J.

    1996-06-01

    Comparing with the exact solutions of the model system of one and two particles coupled to an axial rotor, the quality of the semi classical tilted axis cranking approximation is investigated. Extensive comparisons of the energies and M1 and E2 transition probabilities are carried out for the lowest bands. Very good agreement is found, except near band crossings. Various recipes to take into account finite K within the frame of the usual principal axis cranking are included into the comparison. A set of rules is suggested that permits to construct the excited bands from the cranking configurations, avoiding spurious states. (orig.)

  15. Optical Three-Axis Tactile Sensor for Robotic Fingers

    OpenAIRE

    Ohka, Masahiro; Takata, Jumpei; Kobayashi, Hiroaki; Suzuki, Hirofumi; Morisawa, Nobuyuki; Yussof, Hanafiah Bin

    2008-01-01

    A new three-axis tactile sensor to be mounted on multi-fingered hands is developed based on the principle of an optical waveguide-type tactile sensor comprised of an acrylic hemispherical dome, a light source, an array of rubber sensing elements, and a CCD camera. The sensing element of the present tactile sensor includes one columnar feeler and eight conical feelers. A three-axis force applied to the tip of the sensing element is detected by the contact areas of the conical feelers, which ma...

  16. Winter vitamin D3 supplementation does not increase muscle strength, but modulates the IGF-axis in young children

    DEFF Research Database (Denmark)

    Mortensen, Charlotte; Mølgaard, Christian; Hauger, Hanne

    2018-01-01

    dynamometer, fat mass index (FMI), fat free mass index (FFMI), height, plasma IGF-1, IGF-binding protein 3 (IGFBP-3), and serum 25(OH)D. RESULTS: At baseline, serum 25(OH)D was positively associated with muscle strength, FFMI, and IGFBP-3 in girls only (all p muscle......PURPOSE: To explore whether muscle strength, the insulin-like growth factor axis (IGF-axis), height, and body composition were associated with serum 25-hydroxyvitamin D [25(OH)D] and affected by winter vitamin D supplementation in healthy children, and furthermore to explore potential sex...... differences. METHODS: We performed a double-blind, placebo-controlled, dose-response winter trial at 55ºN. A total of 117 children aged 4-8 years were randomly assigned to either placebo, 10, or 20 µg/day of vitamin D3 for 20 weeks. At baseline and endpoint, we measured muscle strength with handgrip...

  17. Radiation dose reduction through combining positron emission tomography/computed tomography (PET/CT) and diagnostic CT in children and young adults with lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Zhihua; Gates, Erica L.; Trout, Andrew T. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); O' Brien, Maureen M. [Cincinnati Children' s Hospital Medical Center, Division of Oncology, Cancer and Blood Disease Institute, Cincinnati, OH (United States)

    2018-02-15

    Both [F-18]2-fluoro-2-deoxyglucose positron emission tomography/computed tomography ({sup 18}F-FDG PET/CT) and diagnostic CT are at times required for lymphoma staging. This means some body segments are exposed twice to X-rays for generation of CT data (diagnostic CT + localization CT). To describe a combined PET/diagnostic CT approach that modulates CT tube current along the z-axis, providing diagnostic CT of some body segments and localization CT of the remaining body segments, thereby reducing patient radiation dose. We retrospectively compared total patient radiation dose between combined PET/diagnostic CT and separately acquired PET/CT and diagnostic CT exams. When available, we calculated effective doses for both approaches in the same patient; otherwise, we used data from patients of similar size. To confirm image quality, we compared image noise (Hounsfield unit [HU] standard deviation) as measured in the liver on both combined and separately acquired diagnostic CT images. We used t-tests for dose comparisons and two one-sided tests for image-quality equivalence testing. Mean total effective dose for the CT component of the combined and separately acquired diagnostic CT exams were 6.20±2.69 and 8.17±2.61 mSv, respectively (P<0.0001). Average dose savings with the combined approach was 24.8±17.8% (2.60±2.51 mSv [range: 0.32-4.72 mSv]) of total CT effective dose. Image noise was not statistically significantly different between approaches (12.2±1.8 HU vs. 11.7±1.5 HU for the combined and separately acquired diagnostic CT images, respectively). A combined PET/diagnostic CT approach as described offers dose savings at similar image quality for children and young adults with lymphoma who have indications for both PET and diagnostic CT examinations. (orig.)

  18. Radiation dose reduction through combining positron emission tomography/computed tomography (PET/CT) and diagnostic CT in children and young adults with lymphoma

    International Nuclear Information System (INIS)

    Qi, Zhihua; Gates, Erica L.; Trout, Andrew T.; O'Brien, Maureen M.

    2018-01-01

    Both [F-18]2-fluoro-2-deoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT) and diagnostic CT are at times required for lymphoma staging. This means some body segments are exposed twice to X-rays for generation of CT data (diagnostic CT + localization CT). To describe a combined PET/diagnostic CT approach that modulates CT tube current along the z-axis, providing diagnostic CT of some body segments and localization CT of the remaining body segments, thereby reducing patient radiation dose. We retrospectively compared total patient radiation dose between combined PET/diagnostic CT and separately acquired PET/CT and diagnostic CT exams. When available, we calculated effective doses for both approaches in the same patient; otherwise, we used data from patients of similar size. To confirm image quality, we compared image noise (Hounsfield unit [HU] standard deviation) as measured in the liver on both combined and separately acquired diagnostic CT images. We used t-tests for dose comparisons and two one-sided tests for image-quality equivalence testing. Mean total effective dose for the CT component of the combined and separately acquired diagnostic CT exams were 6.20±2.69 and 8.17±2.61 mSv, respectively (P<0.0001). Average dose savings with the combined approach was 24.8±17.8% (2.60±2.51 mSv [range: 0.32-4.72 mSv]) of total CT effective dose. Image noise was not statistically significantly different between approaches (12.2±1.8 HU vs. 11.7±1.5 HU for the combined and separately acquired diagnostic CT images, respectively). A combined PET/diagnostic CT approach as described offers dose savings at similar image quality for children and young adults with lymphoma who have indications for both PET and diagnostic CT examinations. (orig.)

  19. Image quality and dose in computed tomography

    International Nuclear Information System (INIS)

    Jurik, A.G.; Jessen, K.A.; Hansen, J.

    1997-01-01

    Radiation exposure to the patient during CT is relatively high, and it is therefore important to optimize the dose so that it is as low as possible but still consistent with required diagnostic image quality. There is no established method for measuring diagnostic image quality; therefore, a set of image quality criteria which must be fulfilled for optimal image quality was defined for the retroperitoneal space and the mediastinum. The use of these criteria for assessment of image quality was tested based on 113 retroperitoneal and 68 mediastinal examinations performed in seven different CT units. All the criteria, except one, were found to be usable for measuring diagnostic image quality. The fulfilment of criteria was related to the radiation dose given in the different departments. By examination of the retroperitoneal space the effective dose varied between 5.1 and 20.0 mSv (milli Sievert), and there was a slight correlation between dose and high percent of ''yes'' score for the image quality criteria. For examination of the mediastinum the dose range was 4.4-26.5 mSv, and there was no significant increment of image quality at high doses. The great variation of dose at different CT units was due partly to differences regarding the examination procedure, especially the number of slices and the mAs (milli ampere second), but inherent dose variation between different scanners also played a part. (orig.). With 6 figs., 6 tabs

  20. When is a dose not a dose?

    International Nuclear Information System (INIS)

    Green, Patrick

    1992-01-01

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

  1. Enhancement of c-axis texture of AlN films by substrate implantation

    International Nuclear Information System (INIS)

    Chen, C.H.; Yeh, J.M.; Hwang, J.

    2005-01-01

    Highly oriented AlN films are successfully deposited on B + implanted Si(1 1 1) substrates in a radio frequency inductively coupled plasma (RF/ICP) system. The implanted energy and dose used for the B + implanted Si(1 1 1) substrates are 200 keV and 10 15 cm -2 , respectively. The c-axis texture of AlN films can be affected by RF gun power and ion implantation. Experimental results show that the full width at half-maximum (FWHM) of AlN(0 0 2) in the X-ray rocking curve measurements decreases with increasing RF gun power. The optimum condition is at 500 W, where the FWHM of the AlN films deposited on Si(1 1 1) with and without B + implantation are 2.77 and 3.17, respectively. In average, the FWHM of the AlN films on B + implanted Si(1 1 1) are less than those on Si(1 1 1) by a factor of ∼10%. The enhancement of c-axis of AlN films due to B + implantation is attributed to the reduction of AlN grains. Raman spectra also suggest that ion implantation plays a role in reducing the tensile stress in AlN films deposited on B + implanted Si(1 1 1)

  2. Neuroactive steroids modulate HPA axis activity and cerebral brain-derived neurotrophic factor (BDNF) protein levels in adult male rats.

    Science.gov (United States)

    Naert, Gaëlle; Maurice, Tangui; Tapia-Arancibia, Lucia; Givalois, Laurent

    2007-01-01

    Depression is characterized by hypothalamo-pituitary-adrenocortical (HPA) axis hyperactivity. In this major mood disorder, neurosteroids and neurotrophins, particularly brain-derived neurotrophic factor (BDNF), seem to be implicated and have some antidepressant effects. BDNF is highly involved in regulation of the HPA axis, whereas neurosteroids effects have never been clearly established. In this systematic in vivo study, we showed that the principal neuroactive steroids, namely dehydroepiandrosterone (DHEA), pregnenolone (PREG) and their sulfate esters (DHEA-S and PREG-S), along with allopregnanolone (ALLO), stimulated HPA axis activity, while also modulating central BDNF contents. In detail, DHEA, DHEA-S, PREG, PREG-S and ALLO induced corticotropin-releasing hormone (CRH) and/or arginine vasopressin (AVP) synthesis and release at the hypothalamic level, thus enhancing plasma adrenocorticotropin hormone (ACTH) and corticosterone (CORT) concentrations. This stimulation of the HPA axis occurred concomitantly with BDNF modifications at the hippocampus, amygdala and hypothalamus levels. We showed that these neurosteroids induced rapid effects, probably via neurotransmitter receptors and delayed effects perhaps after metabolization in other neuroactive steroids. We highlighted that they had peripheral effects directly at the adrenal level by inducing CORT release, certainly after estrogenic metabolization. In addition, we showed that, at the dose used, only DHEA, DHEA-S and PREG-S had antidepressant effects. In conclusion, these results highly suggest that part of the HPA axis and antidepressant effects of neuroactive steroids could be mediated by BDNF, particularly at the amygdala level. They also suggest that neurosteroids effects on central BDNF could partially explain the trophic properties of these molecules.

  3. Dose from radiological examinations

    International Nuclear Information System (INIS)

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

    1976-01-01

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

  4. Experimental characterization of individual pitch controlled vertical axis wind turbine

    NARCIS (Netherlands)

    Leblanc, B.P.; Simao Ferreira, C.

    2017-01-01

    Research into the Vertical Axis Wind Turbine (VAWT) has been progressing over the last few years due to
    the large shift in design constraints for large floating offshore wind turbines by leveraging tools and experience
    from research beginning in the 1970s and lasting until the HAWT

  5. Comparison of aerodynamic models for Vertical Axis Wind Turbines

    DEFF Research Database (Denmark)

    Ferreira, C. Simão; Aagaard Madsen, Helge; Barone, M.

    2014-01-01

    Multi-megawatt Vertical Axis Wind Turbines (VAWTs) are experiencing an increased interest for floating offshore applications. However, VAWT development is hindered by the lack of fast, accurate and validated simulation models. This work compares six different numerical models for VAWTS: a multiple...

  6. Local charge measurement using off-axis electron holography

    DEFF Research Database (Denmark)

    Beleggia, Marco; Gontard, L.C.; Dunin-Borkowski, R.0E.

    2016-01-01

    A model-independent approach based on Gauss’ theorem for measuring the local charge in a specimen from an electron-optical phase image recorded using off-axis electron holography was recently proposed. Here, we show that such a charge measurement is reliable when it is applied to determine the to...

  7. Tilted axis rotation in odd-odd {sup 164}Tm

    Energy Technology Data Exchange (ETDEWEB)

    Reviol, W.; Riedinger, L.L.; Wang, X.Z.; Zhang, J.Y. [Univ. of Tennessee, Knoxville, TN (United States)] [and others

    1996-12-31

    Ten band structures are observed in {sup 164}Tm, among them sets of parallel and anti-parallel couplings of the proton and neutron spins. The Tilted Axis Cranking scheme is applied for the first time to an odd-odd nucleus in a prominent region of nuclear deformation.

  8. An improved computer controlled triple-axis neutron spectrometer

    International Nuclear Information System (INIS)

    Cooper, M.J.; Hall, J.W.; Hutchings, M.T.

    1975-07-01

    A description is given of the computer-controlled triple-axis neutron spectrometer installed at the PLUTO reactor at Harwell. The reasons for an nature of recent major improvements are discussed. Following a general description of the spectrometer, details are then given of the new computerised control system, including the functions of the various programs which are now available to the user. (author)

  9. The GH/IGF-1 axis in ageing and longevity

    Science.gov (United States)

    List, Edward O.; Berryman, Darlene E.; Murrey, John W.

    2014-01-01

    Secretion of growth hormone (GH), and consequently that of insulin-like growth factor 1 (IGF-1), declines over time until only low levels can be detected in individuals aged ≥60 years. This phenomenon, which is known as the ‘somatopause’, has led to recombinant human GH being widely promoted and abused as an antiageing drug, despite lack of evidence of efficacy. By contrast, several mutations that decrease the tone of the GH/IGF-1 axis are associated with extended longevity in mice. In humans, corresponding or similar mutations have been identified, but whether these mutations alter longevity has yet to be established. The powerful effect of reduced GH activity on lifespan extension in mice has generated the hypothesis that pharmaceutically inhibiting, rather than increasing, GH action might delay ageing. Moreover, mice as well as humans with reduced activity of the GH/IGF-1 axis are protected from cancer and diabetes mellitus, two major ageing-related morbidities. Here, we review data on mouse strains with alterations in the GH/IGF-1 axis and their effects on lifespan. The outcome of corresponding or similar mutations in humans is described, as well as the potential mechanisms underlying increased longevity and the therapeutic benefits and risks of medical disruption of the GH/IGF-1 axis in humans. PMID:23591370

  10. Lake Malawi cichlid evolution along a benthic/limnetic axis.

    Science.gov (United States)

    Hulsey, C D; Roberts, R J; Loh, Y-H E; Rupp, M F; Streelman, J T

    2013-07-01

    Divergence along a benthic to limnetic habitat axis is ubiquitous in aquatic systems. However, this type of habitat divergence has largely been examined in low diversity, high latitude lake systems. In this study, we examined the importance of benthic and limnetic divergence within the incredibly species-rich radiation of Lake Malawi cichlid fishes. Using novel phylogenetic reconstructions, we provided a series of hypotheses regarding the evolutionary relationships among 24 benthic and limnetic species that suggests divergence along this axis has occurred multiple times within Lake Malawi cichlids. Because pectoral fin morphology is often associated with divergence along this habitat axis in other fish groups, we investigated divergence in pectoral fin muscles in these benthic and limnetic cichlid species. We showed that the eight pectoral fin muscles and fin area generally tended to evolve in a tightly correlated manner in the Lake Malawi cichlids. Additionally, we found that larger pectoral fin muscles are strongly associated with the independent evolution of the benthic feeding habit across this group of fish. Evolutionary specialization along a benthic/limnetic axis has occurred multiple times within this tropical lake radiation and has produced repeated convergent matching between exploitation of water column habitats and locomotory morphology.

  11. The somatotropic axis: Effects on brain and cognitive functions

    NARCIS (Netherlands)

    Quik, E.H.

    2012-01-01

    Both hormones of the somatotropic axis, insulin-like growth factor-1 (IGF-1) and growth hormone (GH) can cross the blood-brain barrier and bind to their receptors in neurons and glia throughout the brain. Features of aging resemble those of GHD and aging is also associated with a decline in the

  12. Locating an axis-parallel rectangle on a Manhattan plane

    DEFF Research Database (Denmark)

    Brimberg, Jack; Juel, Henrik; Körner, Mark-Christoph

    2014-01-01

    In this paper we consider the problem of locating an axis-parallel rectangle in the plane such that the sum of distances between the rectangle and a finite point set is minimized, where the distance is measured by the Manhattan norm 1. In this way we solve an extension of the Weber problem...

  13. Serotonergic stimulation of the rat hypothalamo-pituitary-adrenal axis

    DEFF Research Database (Denmark)

    Mikkelsen, Jens D; Hay-Schmidt, Anders; Kiss, Alexander

    2004-01-01

    Acute stimulation of the hypothalamo-pituitary-adrenal (HPA) axis by selective serotonin reuptake inhibitors (SSRIs) is mediated by several postsynaptic 5-HT receptor subtypes. Activation of 5-HT(1A) and 5-HT(2A) receptors increases plasma corticosterone levels, and it is likely that these recept...