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Sample records for 131mxe 133mxe 133xe

  1. Prospective use of xenon /sup 133/Xe clearance for amputation level selection

    SciTech Connect

    Moore, W.S.; Henry, R.E.; Malone, J.M.; Daly, M.J.; Patton, D.; Childers, S.J.

    1981-01-01

    Xenon /sup 133/Xe clearance was used to select the most distal amputation level that would allow sufficient blood flow for healing. Capillary blood flow was first measured at the most distal potential amputation level, then at successive proximal levels until an amputation site was found that had a capillary skin blood flow rate greater than or equal to 2.6 mL/min/100 g of tissue. Xenon /sup 133/Xe in saline was injected intracutaneously at each level, and flow rates were determined using a gamma camera interfaced with a computer system programmed for the Ketty-Schmidt formula modified for capillary blood flow. There were 45 cases, including one toes, six transmetatarsal, five Syme's, 25 below-knee, four knee disarticulation, three above-knee, and one hip disarticulation amputation. All amputations in patients with flow rates exceeding 2.4 mL/min/100 g of tissue healed, with two exceptions.

  2. Detection of (133)Xe from the Fukushima nuclear power plant in the upper troposphere above Germany.

    PubMed

    Simgen, Hardy; Arnold, Frank; Aufmhoff, Heinfried; Baumann, Robert; Kaether, Florian; Lindemann, Sebastian; Rauch, Ludwig; Schlager, Hans; Schlosser, Clemens; Schumann, Ulrich

    2014-06-01

    After the accident in the Japanese Fukushima Dai-ichi nuclear power plant in March 2011 large amounts of radioactivity were released and distributed in the atmosphere. Among them were also radioactive noble gas isotopes which can be used as tracers to test global atmospheric circulation models. This work presents unique measurements of the radionuclide (133)Xe from Fukushima in the upper troposphere above Germany. The measurements involve air sampling in a research jet aircraft followed by chromatographic xenon extraction and ultra-low background gas counting with miniaturized proportional counters. With this technique a detection limit of the order of 100 (133)Xe atoms in liter-scale air samples (corresponding to about 100 mBq/m(3)) is achievable. Our results provide proof that the (133)Xe-rich ground level air layer from Fukushima was lifted up to the tropopause and distributed hemispherically. Moreover, comparisons with ground level air measurements indicate that the arrival of the radioactive plume at high altitude over Germany occurred several days before the ground level plume.

  3. Penile xenon (/sup 133/Xe) washout: a rapid method of screening for vasculogenic impotence

    SciTech Connect

    Nseyo, U.O.; Wilbur, H.J.; Kang, S.A.; Flesh, L.; Bennett, A.H.

    1984-01-01

    The radioactive inert gas xenon (/sup 133/Xe) is a well-established isotopic indicator used to assess vascular status in many organ systems. Xenon-133 was used to evaluate male impotence. Xenon-133 was injected subcutaneously at the level of the coronal sulcus in the detumescent state. Using the gamma camera, sequential images were obtained and computer-generated curves calculated. The clearance time for 50 per cent washout of the injected /sup 133/Xe (T1/2) was then calculated for each patient, as well as a control group. Preliminary findings indicate a correlation with such established techniques of evaluating erectile impotence as history, physical examination, penile pulse Doppler tracings, and brachial-penile blood pressure index. The xenon-133 washout study was a rapid, minimally invasive, reproducible, and cost-effective method of screening those impotent patients for vasculogenic etiology of their erectile impotence. We recommend the addition of this method to the surgeon engaged in the care of impotent males.

  4. Atmospheric transport modelling of time resolved 133Xe emissions from the isotope production facility ANSTO, Australia.

    PubMed

    Schöppner, M; Plastino, W; Hermanspahn, N; Hoffmann, E; Kalinowski, M; Orr, B; Tinker, R

    2013-12-01

    The verification of the Comprehensive Nuclear-Test Ban Treaty (CTBT) relies amongst other things on the continuous and worldwide monitoring of radioxenon. The characterization of the existing and legitimate background, which is produced mainly by nuclear power plants and isotope production facilities, is of high interest to improve the capabilities of the monitoring network. However, the emissions from legitimate sources can usually only be estimated. For this paper historic source terms of (133)Xe emissions from the isotope production facility at ANSTO, Sydney, Australia, have been made available in a daily resolution. Based on these high resolution data, different source term sets with weekly, monthly and yearly time resolution have been compiled. These different sets are then applied together with atmospheric transport modelling (ATM) to predict the concentration time series at two radioxenon monitoring stations. The results are compared with each other in order to examine the improvement of the prediction capability depending on the used time resolution of the most dominant source term in the region.

  5. Cerebral effects of scalp cooling and extracerebral contribution to calculated blood flow values using the intravenous 133Xe technique.

    PubMed

    Friberg, L; Kastrup, J; Hansen, M; Bülow, J

    1986-06-01

    With the intravenous 133Xe technique we measured cerebral blood flow (CBF) in eight healthy subjects during normal subcutaneous temperatures and during extracranial cooling. This gave rise to the possibility of evaluating the contribution of the extracerebral blood flow to the calculation of CBF values. With a two-compartmental analysis of the wash-out curves during cooling there was a significant reduction of the CBF indices f1, representing mainly fast blood flow in the grey matter and f2, representing blood flow in the slowly perfused white matter and extracerebral structures. The reduction of f1 was due to the 'slippage' phenomenon:calculation of f1 was affected by a reduction in f2 due to a considerably reduced extracerebral blood flow. The initial slope index (ISI) calculated from 30 to 90 s of the first part of the presumed mono-exponential 133Xe wash-out curve was not affected by slippage as the ISI remained unchanged in spite of reduced extracerebral blood flow. It is concluded that CBF was unaffected by extracranial cooling. Extracranial cooling can be used to reduce the extracerebral blood flow contribution to the calculated CBF values.

  6. Cerebral hemodynamics in normal-pressure hydrocephalus. Evaluation by 133Xe inhalation method and dynamic CT study

    SciTech Connect

    Tamaki, N.; Kusunoki, T.; Wakabayashi, T.; Matsumoto, S.

    1984-09-01

    Cerebral hemodynamics in 31 patients with suspected normal-pressure hydrocephalus were studied by means of the xenon-133 (133Xe) inhalation method and on dynamic computerized tomography (CT) scanning. Cerebral blood flow (CBF) is reduced in all patients with dementia. Hypoperfusion was noted in a frontal distribution in these patients compared with normal individuals. There was no difference in CBF patterns between patients with good and those with poor outcome. The CBF was increased following cerebrospinal fluid (CSF) shunting in patients who responded to that procedure: increase in flow correlated with clinical improvement, frontal and temporal lobe CBF was most markedly increased, and the CBF pattern became normal. In contrast, CBF was decreased after shunt placement in patients who were considered to have suffered from degenerative dementia, as evidenced by non-response to shunting. Dynamic computerized tomography studies demonstrated that patients with a good outcome showed a postoperative reduction in mean transit time of contrast material, most prominent in the frontal and temporal gray matter, and slight in the deep frontal structures, but not in the major cerebral vessels. Patients with poor outcome after shunting, however, had an increase in transit time in all regions. This corresponded well with the results as determined by the 133Xe inhalation method.

  7. Relationship of 133Xe cerebral blood flow to middle cerebral arterial flow velocity in men at rest

    NASA Technical Reports Server (NTRS)

    Clark, J. M.; Skolnick, B. E.; Gelfand, R.; Farber, R. E.; Stierheim, M.; Stevens, W. C.; Beck, G. Jr; Lambertsen, C. J.

    1996-01-01

    Cerebral blood flow (CBF) was measured by 133Xe clearance simultaneously with the velocity of blood flow through the left middle cerebral artery (MCA) over a wide range of arterial PCO2 in eight normal men. Average arterial PCO2, which was varied by giving 4% and 6% CO2 in O2 and by controlled hyperventilation on O2, ranged from 25.3 to 49.9 mm Hg. Corresponding average values of global CBF15 were 27.2 and 65.0 ml 100 g min-1, respectively, whereas MCA blood-flow velocity ranged from 42.8 to 94.2 cm/s. The relationship of CBF to MCA blood-flow velocity over the imposed range of arterial PCO2 was described analytically by a parabola with the equation: CBF = 22.8 - 0.17 x velocity + 0.006 x velocity2 The observed data indicate that MCA blood-flow velocity is a useful index of CBF response to change in arterial PCO2 during O2 breathing at rest. With respect to baseline values measured while breathing 100% O2 spontaneously, percent changes in velocity were significantly smaller than corresponding percent changes in CBF at increased levels of arterial PCO2 and larger than CBF changes at the lower arterial PCO2. These observed relative changes are consistent with MCA vasodilation at the site of measurement during exposure to progressive hypercapnia and also during extreme hyperventilation hypocapnia.

  8. Measurement of blood flow by the 133Xe clearance technique to grafts of amnion used in vestibuloplasty.

    PubMed

    Güler, R; Ercan, M T; Ulutunçel, N; Devrim, H; Uran, N

    1997-08-01

    The purpose of this study was to determine the blood supply to lyophilized amniotic membranes when used as graft material in vestibuloplasties. 133Xe clearance technique was used to measure the blood flow to the grafts. A total of 20 patients had either Clark (10) or Kazanjian (10) vestibuloplasties. The blood flow was determined at 2-3 days preoperatively and at 10 and 30 days postoperatively. The preoperative mandibular anterior alveolar mucosal blood flow was 34.4 +/- 10.7 and 23.1 +/- 13.1 ml/100 g/min for the Clark and Kazanjian groups, respectively. Ten days after vestibuloplasty operation with lyophilized amniotic membrane graft application the blood flow to the graft increased to 56.8 +/- 45.4 and 62.6 +/- 30.4 ml/100 g/min for the Clark and Kazanjian groups, respectively. The corresponding values at 30 days postoperatively were 24.6 +/- 10.2 and 22.2 +/- 9.2 ml/100 g/min, indicating the return to normal levels. The changes in blood flow as a function of time were statistically significant in each group (P<0.05). Our results demonstrated the angiogenic effect of lyophilized amniotic membranes until mucoid degeneration after 10-15 days.

  9. Effects of selected materials and geometries on the beta dose equivalent rate in a tissue equivalent phantom immersed in infinite clouds of 133Xe.

    PubMed

    Piltingsrud, H V; Gels, G L

    1986-06-01

    Most calculations of dose equivalent (D.E.) rates at 70-micron tissue depths in tissue equivalent (T.E.) phantoms from infinite clouds (radius exceeds maximum beta range in air) of 133Xe do not consider the possible effects of clothing overlays. Consequently, a series of measurements were made using a 1-mm-thick plastic scintillation detector assembly mounted in a tissue equivalent (T.E.) phantom with an overlay of 70 micron of T.E. material. This assembly was placed in an infinite cloud containing a known concentration of 133Xe. Material samples were placed at selected distances from the detector phantom, both individually and in various combinations. Pulse-height spectra resulting from beta radiations were converted to relative D.E. rates at a 70-micron tissue depth. The relative D.E. rates were reduced from values with no clothing cover by as little as 45% when placing a single thin nylon cloth 1 cm from the phantom, to 94% for a T-shirt material plus wool material plus denim placed 1/2, 1 and 3 cm, respectively, from the phantom. The results indicate that even loosely fitting clothing can have an important effect on reducing the D.E. rate. Close-fitting clothing appears to provide better protection.

  10. Crossed cerebellar diaschisis in ischemic stroke: a study of regional cerebral blood flow by /sup 133/Xe inhalation and single photon emission computerized tomography

    SciTech Connect

    Meneghetti, G.; Vorstrup, S.; Mickey, B.; Lindewald, H.; Lassen, N.A.

    1984-06-01

    Seventy measurements of CBF were performed in 12 stroke patients by /sup 133/Xe inhalation and a rapidly rotating single photon emission computerized tomograph. CBF was measured every other day during the acute phase and at 2- and 6-month follow-up visits. A persistent contralateral cerebellar blood flow depression was evident in five patients with severe hemispheric low flow areas, which correlated with large, hypodense lesions on the computerized tomographic scan. In a sixth patient with a small, deep infarct, a transient crossed cerebellar low flow was observed, while the clinical symptoms persisted. It is concluded from this serial study that crossed cerebellar diaschisis is a common finding in completed stroke. It is probably caused by disconnection of the corticopontine pathways, a disconnection that tends to persist. The phenomenon is in fact less variable than the stroke-related CBF changes in the infarcted hemisphere, in which a period of relative hyperemia is frequently seen.

  11. Reproducibility of the /sup 133/Xe inhalation technique in resting studies: task order and sex related effects in healthy young adults

    SciTech Connect

    Warach, S.; Gur, R.C.; Gur, R.E.; Skolnick, B.E.; Obrist, W.D.; Reivich, M.

    1987-12-01

    Repeated applications of the /sup 133/Xe inhalation technique for measuring regional CBF (rCBF) were made during consecutive resting conditions in a sample of young healthy subjects. Subjects were grouped by order and by sex (nine had resting studies as the initial two measurements in a series of four measurement (six men, three women) and six had these measurements later (two men, four women)). Three flow parameters were examined: f1 (fast flow) and IS (initial slope) for gray matter CBF, and CBF-15 for mean CBF (gray and white matter over 15-min integration), as well as w1, the percentage of tissue with fast clearing characteristics. With all groups combined, there were no significant differences between the two resting measurements, and high test-retest correlations were obtained for the flow parameters and w1. Analyses by order and sex grouping revealed, for the flow parameters, significant interactions of test-retest difference with order. Repeated initial studies showed reduced CBF from the first to second measurement, whereas resting studies performed later in the series showed no reduction. Interactions for test-retest difference with sex indicated that reduced CBF in serial measures was more pronounced for women. No hemispheric or regional specificity to account for these effects was found. Correction for PaCO/sub 2/ differences did not alter these results. The results resemble data regarding habituation effects measured for other psychophysiologic measures, and suggest that reduction in CBF for consecutive measurements made on the same day may reflect habituation. This underscores the importance of controlling for effects of habituation on serial measurements of CBF and metabolism.

  12. Computation and Analysis of the Global Distribution of the Radioxenon Isotope 133Xe based on Emissions from Nuclear Power Plants and Radioisotope Production Facilities and its Relevance for the Verification of the Nuclear-Test-Ban Treaty

    NASA Astrophysics Data System (ADS)

    Wotawa, Gerhard; Becker, Andreas; Kalinowski, Martin; Saey, Paul; Tuma, Matthias; Zähringer, Matthias

    2010-05-01

    Monitoring of radioactive noble gases, in particular xenon isotopes, is a crucial element of the verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The capability of the noble gas network, which is currently under construction, to detect signals from a nuclear explosion critically depends on the background created by other sources. Therefore, the global distribution of these isotopes based on emissions and transport patterns needs to be understood. A significant xenon background exists in the reactor regions of North America, Europe and Asia. An emission inventory of the four relevant xenon isotopes has recently been created, which specifies source terms for each power plant. As the major emitters of xenon isotopes worldwide, a few medical radioisotope production facilities have been recently identified, in particular the facilities in Chalk River (Canada), Fleurus (Belgium), Pelindaba (South Africa) and Petten (Netherlands). Emissions from these sites are expected to exceed those of the other sources by orders of magnitude. In this study, emphasis is put on 133Xe, which is the most prevalent xenon isotope. First, based on the emissions known, the resulting 133Xe concentration levels at all noble gas stations of the final CTBT verification network were calculated and found to be consistent with observations. Second, it turned out that emissions from the radioisotope facilities can explain a number of observed peaks, meaning that atmospheric transport modelling is an important tool for the categorization of measurements. Third, it became evident that Nuclear Power Plant emissions are more difficult to treat in the models, since their temporal variation is high and not generally reported. Fourth, there are indications that the assumed annual emissions may be underestimated by factors of two to ten, while the general emission patterns seem to be well understood. Finally, it became evident that 133Xe sources mainly influence the sensitivity of the

  13. An evaluation of the external radiation exposure dosimetry and calculation of maximum permissible concentration values for airborne materials containing 18F, 15O, 13N, 11C and 133Xe.

    PubMed

    Piltingsrud, H V; Gels, G L

    1985-11-01

    To better understand the dose equivalent (D.E.) rates produced by airborne releases of gaseous positron-emitting radionuclides under various conditions of cloud size, a study of the external radiation exposure dosimetry of these radionuclides, as well as negatron, gamma and x-ray emitting 133Xe, was undertaken. This included a calculation of the contributions to D.E. as a function of cloud radii, at tissue depths of 0.07 mm (skin), 3 mm (lens of eye) and 10 mm (whole body) from both the particulate and photon radiations emitted by these radionuclides. Estimates of maximum permissible concentration (MPC) values were also calculated based on the calculated D.E. rates and current regulations for personnel radiation protection (CFR84). Three continuous air monitors, designed for use with 133Xe, were evaluated for applications in monitoring air concentrations of the selected positron emitters. The results indicate that for a given radionuclide and for a cloud greater than a certain radius, personnel radiation dosimeters must respond acceptably to only the photon radiations emitted by the radionuclide to provide acceptable personnel dosimetry. For clouds under that radius, personnel radiation dosimeters must also respond acceptably to the positron or negatron radiations to provide acceptable personnel dosimetry. It was found that two out of the three air concentration monitors may be useful for monitoring air concentrations of the selected positron emitters.

  14. Effects of prolonged bedrest in antiorthostatic position on rCBF measured by /sup 133/Xe inhalation technique - effects of clonidine

    SciTech Connect

    Guell, A.; Victor, G.; Bru, A.; Montastruc, P.; Bes, A.

    1981-12-01

    Experiments involving prolonged bedrest in antiorthostatic position were performed in order to simulate cardiovascular changes observed in weightlessness. Six young healthy subjects were placed in strict bedrest in a -4-deg antiorthostatic position for seven days. The rCBF (regional cerebral blood flow) measurements were made by an Xe-133 inhalation method. Three of the subjects received 0.450 mg of clonidine during the experiment. A constant increase in rCBF was observed during the first 12 hours in subjects who did not receive clonidine at the 72nd hour, all values returned to the basal state. These findings agree with the rapid correction of hemodynamic disturbances observed in the first days of weightlessness. In subjects treated with clonidine, the increase in rCBF did not occur.

  15. Effect of hematocrit and systolic blood pressure on cerebral blood flow in newborn infants

    SciTech Connect

    Younkin, D.P.; Reivich, M.; Jaggi, J.L.; Obrist, W.D.; Delivoria-Papadopoulos, M.

    1987-06-01

    The effects of hematocrit and systolic blood pressure on cerebral blood flow were measured in 15 stable, low birth weight babies. CBF was measured with a modification of the xenon-133 (/sup 133/Xe) clearance technique, which uses an intravenous bolus of /sup 133/Xe, an external chest detector to estimate arterial /sup 133/Xe concentration, eight external cranial detectors to measure cephalic /sup 133/Xe clearance curves, and a two-compartmental analysis of the cephalic /sup 133/Xe clearance curves to estimate CBF. There was a significant inverse correlation between hematocrit and CBF, presumably due to alterations in arterial oxygen content and blood viscosity. Newborn CBF varied independently of systolic blood pressure between 60 and 84 mm Hg, suggesting an intact cerebrovascular autoregulatory mechanism. These results indicate that at least two of the factors that affect newborn animal CBF are operational in human newborns and may have important clinical implications.

  16. Source term estimation of radioxenon released from the Fukushima Dai-ichi nuclear reactors using measured air concentrations and atmospheric transport modeling.

    PubMed

    Eslinger, P W; Biegalski, S R; Bowyer, T W; Cooper, M W; Haas, D A; Hayes, J C; Hoffman, I; Korpach, E; Yi, J; Miley, H S; Rishel, J P; Ungar, K; White, B; Woods, V T

    2014-01-01

    Systems designed to monitor airborne radionuclides released from underground nuclear explosions detected radioactive fallout across the northern hemisphere resulting from the Fukushima Dai-ichi Nuclear Power Plant accident in March 2011. Sampling data from multiple International Modeling System locations are combined with atmospheric transport modeling to estimate the magnitude and time sequence of releases of (133)Xe. Modeled dilution factors at five different detection locations were combined with 57 atmospheric concentration measurements of (133)Xe taken from March 18 to March 23 to estimate the source term. This analysis suggests that 92% of the 1.24 × 10(19) Bq of (133)Xe present in the three operating reactors at the time of the earthquake was released to the atmosphere over a 3 d period. An uncertainty analysis bounds the release estimates to 54-129% of available (133)Xe inventory.

  17. Radioxenon standards used in laboratory inter-comparisons.

    PubMed

    Gohla, H; Auer, M; Cassette, Ph; Hague, R K; Lechermann, M; Nadalut, B

    2016-03-01

    Preparation methods for (133)Xe standards of activity concentration and the results of the 2014 (133)Xe laboratory inter-comparison exercise are described. One element of the quality assurance/quality control (QA/QC) program for laboratories of the International Monitoring System (IMS) will be regular inter-comparison exercises. However, until recently, no activity concentration standards for benchmarking were available. Therefore, two (133)Xe activity concentration reference standards were produced independently by Idaho National Laboratory and Seibersdorf Laboratories and used for the 2014 laboratory inter-comparison exercise. The preparation of a complementary (127)Xe activity concentration standard as well as a (127)Xe laboratory inter-comparison exercise suggests (127)Xe as a suitable isotope for QA/QC of remote IMS noble gas stations.

  18. Detection of radioxenon in Darwin, Australia following the Fukushima Dai-ichi nuclear power plant accident.

    PubMed

    Orr, Blake; Schöppner, Michael; Tinker, Rick; Plastino, Wolfango

    2013-12-01

    A series of (133)Xe detections in April 2011 made at the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO) International Monitoring System noble gas station in Darwin, Australia, were analysed to determine the most likely source location. Forward and backwards atmospheric transport modelling simulations using FLEXPART were conducted. It was shown that the most likely source location was the Fukushima Dai-ichi nuclear power plant accident. Other potential sources in the southern hemisphere were analysed, including the Australian Nuclear Science and Technology Organisation (ANSTO) radiopharmaceutical facility, but it was shown that sources originating from these locations were highly unlikely to be the source of the observed (133)Xe Darwin detections.

  19. Simulating the venting of radioactivity from a soviet nuclear test

    NASA Astrophysics Data System (ADS)

    Rodriguez, Daniel J.; Peterson, Kendall R.

    Fresh fission products were found in several routine air samples in Europe during the second and third weeks of March 1987. Initially, it was suspected that the radionuclides, principally 133Xe and 131I, had been accidentally released from a European facility handling nuclear materials. However, the announcement of an underground nuclear test at Semipalatinsk, U.S.S.R. on 26 February 1987 suggested that the elevated amounts of radioactivity may, instead, have been caused by a venting episode. Upon learning of these events, we simulated the transport and diffusion of 133Xe with our Hemispheric MEDIC and ADPIC models, assuming Semipalatinsk to be the source of the radioactive emissions. The correspondence between the calculated concentrations and the daily average 133Xe measurements made by the Federal Office for Civil Protection in F.R.G. was excellent. While this agreement does not, in itself, prove that an atmospheric venting of radioactive material occurred at Semipalatinsk, a body of circumstantial evidence exists which, when added together, strongly supports this conclusion. Our calculations suggested a total fission yield of about 40 kt, which is within the 20-150 kt range of tests acknowledged by the U.S.S.R. Finally, dose calculations indicated that no health or environmental impact occurred outside of the U.S.S.R. due to the suspected venting of 133Xe. However, the inhalation dose resulting from 133I, an unmodeled component of the radioactive cloud, represented a greater potential risk to public health.

  20. Triple Coincidence Radioxenon Detector

    SciTech Connect

    McIntyre, Justin I.; Aalseth, Craig E.; Bowyer, Ted W.; Hayes, James C.; Heimbigner, Tom R.; Morris, Scott J.; Reeder, Paul L.

    2004-09-22

    The Automated Radioxenon Sampler/Analyzer (ARSA) built by Pacific Northwest National Laboratory (PNNL) is on e of the world’s most sensitive systems for monitoring the four radioxenon isotopes 133Xe, 133mXE, 131mXe and 135Xe. However, due to size, weight and power specifications appropriate to meet treaty-monitoring requirements; the ARSA is unsuitable for rapid deployment using modest transportation means. To transition this technology to a portable unit can be easily and rapidly deployed can be achieved by significant reductions in size, weight and power consumption if concentration were not required. As part of an exploratory effort to reduce both the size of the air sample and the gas processing requirement PNNL has developed an experimental nuclear detector to test and qualify the use of triple coincidence signatures (beta, conversion electron, x-ray) from two of the radioxenon isotopes (135Xe and 133Xe) as well as the more traditional beta-gamma coincidence signatures used by the ARSA system. The additional coincidence requirement allows for reduced passive shielding, and makes it possible for unambiguous detection of 133Xe and 153Xe in the presence of high 222Rn backgrounds. This paper will discuss the experimental setup and the results obtained for a 133Xe sample with and without 222Rn as an interference signature.

  1. Method for detection of nuclear-plasma interactions in a 134Xe-doped exploding pusher at the National Ignition Facility

    DOE PAGES

    Bleuel, Daniel L.; Bernstein, Lee A.; Brand, Christopher A.; ...

    2016-06-10

    Angular momentum changes due to nuclear-plasma interactions on highly-excited nuclei in high energy density plasmas created at the National Ignition Facility can be measured through a change in isomer feeding following gamma emission. Here, we propose an experiment to detect these effects in 133Xe* in exploding pusher capsules.

  2. Hemodynamics of erection in man

    SciTech Connect

    Shirai, M.; Ishii, N.

    1981-02-01

    Inquiry was made into the theory that closure of the efferent vein from the corpora cavernosa is essential for erection of the human penis. To determine whether the venous closure is indeed a prerequisite to human penile erection, two tests were carried out in men: (1) direct infusion in 133Xe into corpora cavernosa and (2) performance of carvernosography. In each case, penile erection was induced by providing the subject with sexual stimulation. The behavioral changes were studied through the 133Xe clearance curve and the contrast medium, respectively. When the penis remained flaccid, the 133Xe clearance curve followed a gentle path and the contrast medium could be noted within the penis for a relatively long period. However, on erection with sexual stimulation, the 133Xe clearance curve fell rapidly instead of following the gentle course expected in the case of venous closure. Also, the contrast medium quickly flowed out of the corpora cavernosa. The human penis therefore can well erect without closure of the efferent vein from the corpora cavernosa.

  3. Partition of xenon and iodoantipyrine among erythrocytes, plasma, and myocardium.

    PubMed

    Carlin, R; Chien, S

    1977-05-01

    A new method was developed for determining directly the distribution of 133Xe between red cells and plasma in vitro without an air-fluid interface; the partitioning of 133Xe and 133-i-iodantipyrine between blood and myocardium was investigated in the dog in situ. The red cell-plasma partition coefficient for 133Xe (lambdacpX, unit: ml/ml) at 37 degrees C was 2.27 +/- 0.07 (mean +/- SD) for human blood and 3.31 +/- 0.06 for dog blood. The red cell-plasma partition coefficient for 131I-iodantipyrine (lambdacpI, ml/ml) was 0.75 +/- 0.04 for human blood and 0.97 +/- 0.03 for dog blood. lambdacpX and lambdacpI did not change significantly after the intravenous administration of sodium pentobarbital (30 mg/kg) into the dog. lambdacpX of dog blood varied inversely with temperature, whereas lambdacpI showed very little change with temperature. The blood-left ventricle partition coefficient for 133Xe (lambda'btX, corrected for trapped blood) varied directly with directly with red cell volume fraction (H): lambda'btX = 1.32 + 2.00 H. Blood-left ventricle partition coefficient for 131I-iodoanitpyrine did not vary significantly with H. The results support the concept of a three-compartment partition of the indicator among erythrocytes, plasma, and myocardium. The mean values (+/- SD) of the hematocrit-independent plasma-tissue partition coefficient in the left ventricle for 133Xe and 131I-iodoantipyrine were 1.08 +/- 0.16 and 1.54 +/- 0.20 g/ml, respectively.

  4. Adrenergic vasoconstriction in peripheral nerves of the rabbit

    SciTech Connect

    Selander, D.; Mansson, L.G.; Karlsson, L.; Svanvik, J.

    1985-01-01

    The blood flow in the sciatic nerve of the rabbit was estimated from the wash out of intraneurally injected /sup 133/Xe. To avoid diffusion of the tracer into the surrounding muscular tissue, the nerve was covered by a gas-tight plastic film. Using this technique, the basal blood flow in the sciatic nerve was estimated to 35 ml X min-1 X 100 g-1. It was found that intraarterial norepinephrine and electrical stimulation of the lumbar sympathetic chain strongly reduced the wash out of /sup 133/Xe, which only can be explained by a pronounced reduction of the blood flow in the nerve itself. The blood flow again increased within 4 min of stopping the infusion of norepinephrine or the sympathetic stimulation. The prolonged effect and higher neurotoxicity of local anesthetics containing adrenaline may be explained by an alpha receptor-mediated vasoconstriction of the microvessels of peripheral nerves.

  5. Calculation of Minimum-Detectable-Concentration Levels of Radioxenon Isotopes Using the PNNL ARSA System

    SciTech Connect

    McIntyre, Justin I.; Bowyer, Ted W.; Reeder, Paul L.

    2006-03-11

    Measurement of xenon fission product isotopes is a key element in the global network being established to monitor the Comprehensive Nuclear-Test-Ban Treaty. The automated Radio-xenon Analyzer/Sampler (ARSA), built by Pacific Northwest National Laboratory, can detect 131mXe, 133mXe, 133Xe, and 135Xe via a beta-gamma counting system. Due to the variable background and sources of these four radio-xenon isotopes, it is important to have as sensitive a detection system as possible and to quantify the Minimum-Detectable-Concentrations (MDC) that such a system will be able to detect to preclude false negative and false positive results. From data obtained from IAR in Germany MDC values for 133Xe were well below the 1 mBq/SCMA as required by the PTS for the Comprehensive Test BAn Treaty [WGB TL-11,1999].

  6. [A case of subacute stroke with high uptake of 99mTc-HMPAO in the reperfused infarct corresponding to low perfusion area].

    PubMed

    Sugawara, Y; Tanada, S; Murase, K; Inoue, T; Miki, H; Okumura, A; Hamamoto, K; Ueda, T; Ohta, S; Sakaki, S

    1994-06-01

    We reported a case of subacute stroke which showed high uptake of 99mTc-d,l-hexamethylpropyleneamine oxime (HMPAO) in the reperfused infarct corresponding to slightly decreased perfusion by 133Xe inhalation CBF measurement. In the chronic stage, both SPECT images of 99mTc-HMPAO and 133Xe showed low perfusion in the affected lesion. It was, therefore, considered that the high uptake of 99mTc-HMPAO had represented luxury perfusion. In the subacute stage of stroke, high uptake of 99mTc-HMPAO may imply luxury perfusion but not always hyperperfusion. It is suggested that the fractional fixation of 99mTc-HMPAO temporarily change in the affected lesion and it is essential to take into consideration the clinical stage for the interpretation of SPECT images.

  7. Cerebral blood flow studied by Xenon-133 inhalation technique in parkinsonism: loss of hyperfrontal pattern

    SciTech Connect

    Bes, A.; Gueell, A.; Fabre, N.; Dupui, P.; Victor, G.; Geraud, G.

    1983-03-01

    Cerebral blood flow (grey matter flow) in parkinsonism requires further investigation. The noninvasive method of /sup 133/Xe inhalation permits study of larger numbers of subjects than previously used invasive techniques such as the intracarotid /sup 133/Xe injection method. Measurements were made in this laboratory in 30 subjects having Parkinson's disease. Mean hemispheric blood flow (F1) values were 70.4 +/- 9.3 ml/100 g/min, compared to 76.3 for a group of age-matched normal subjects, which is a decrease of -7.8%. The most striking difference was the loss of the hyperfrontal distribution in parkinsonism. The prefrontal F1 values were only 1.8% greater than the hemisphere grey matter flow, compared with 8.5% in controls of a similar age group.

  8. Understanding radioxenon isotopical ratios originating from radiopharmaceutical facilities

    NASA Astrophysics Data System (ADS)

    Saey, P. R. J.; Ringbom, A.; Bowyer, T. W.; Becker, A.; de Geer, L.-E.; Nikkinen, M.; Payne, R. F.

    2009-04-01

    It was recently shown that radiopharmaceutical facilities (RPF) are major contributors to the general background of 133Xe and other xenon isotopes both in the northern and southern hemisphere. To distinguish a nuclear explosion signal from releases from civil nuclear facilities, not only the activity concentrations but also the ratios of the four different CTBT relevant radioxenon isotopes (131mXe, 133mXe, 133Xe and 135Xe) have to be well understood. First measurements taken recently in and around two of the world's largest RPF's: NTP at Pelindaba, South Africa and IRE at Fleurus, Belgium have been presented. At both sites, also stack samples were taken in close cooperation with the facility operators. The radioxenon in Belgium could be classified in four classes: the normal European background (133Xe activity between 0 - 5 mBq/m3) on one hand and then the samples where all four isotopes were detected with 133mXe/131mXe > 1. In northern South Africa the Pelindaba RPF is in practice the sole source of radioxenon. It generated a background of 133Xe at the measurement site some 230 km to the west of the RPF of 0 - 5 mBq/m3. In the cases where the air from the Pelindaba facility reached the measurement site directly and in a short time period, the 133Xe was higher, also 135Xe was present and in some samples 133mXe as well. The ratios of the activity concentrations of 135Xe/133Xe vs. 133mXe/131mXe (Multiple Isotope Ratio Plot - MIRC) have been analysed. For both facilities, the possible theoretical ratio's for different scenarios were calculated with the information available and compared with the measurements. It was found that there is an excess of 131mXe present in the European samples compared to theoretical calculations. A similar excess has also been seen in samples measured in northern America. In South Africa, neither the environmental samples nor the stack ones contained 131mXe at measurable levels. This can probably be explained by different processes and

  9. Analysis of radioxenon and Krypton-85 at the BfS noble gas laboratory.

    PubMed

    Schlosser, C; Bollhöfer, A; Schmid, S; Krais, R; Bieringer, J; Konrad, M

    2016-12-28

    Proportional counters and a β-γ coincidence system and their performance characteristics are described, with emphasis on internal and external quality controls. Typical limits of detection (LD) are 8mBqm(-3) for (85)Kr and 4mBqm(-3) for (133)Xe for the proportional counters, while for similar xenon volumes the LD for (133)Xe in the β-γ system is approximately 4 times lower. Results of comparative analyses agree above the limit of quantification. Xenon-133 levels in southern Germany are presently at or below the LD of the proportional counters, but above the LD of the β-γ system, which is now routinely used for analysis of environmental samples.

  10. Noninvasive method of estimating human newborn regional cerebral blood flow

    SciTech Connect

    Younkin, D.P.; Reivich, M.; Jaggi, J.; Obrist, W.; Delivoria-Papadopoulos, M.

    1982-12-01

    A noninvasive method of estimating regional cerebral blood flow (rCBF) in premature and full-term babies has been developed. Based on a modification of the /sup 133/Xe inhalation rCBF technique, this method uses eight extracranial NaI scintillation detectors and an i.v. bolus injection of /sup 133/Xe (approximately 0.5 mCi/kg). Arterial xenon concentration was estimated with an external chest detector. Cerebral blood flow was measured in 15 healthy, neurologically normal premature infants. Using Obrist's method of two-compartment analysis, normal values were calculated for flow in both compartments, relative weight and fractional flow in the first compartment (gray matter), initial slope of gray matter blood flow, mean cerebral blood flow, and initial slope index of mean cerebral blood flow. The application of this technique to newborns, its relative advantages, and its potential uses are discussed.

  11. Factors affecting the adsorption of xenon on activated carbon

    SciTech Connect

    Underhill, D.W.; DiCello, D.C.; Scaglia, L.A.; Watson, J.A.

    1986-08-01

    The presence of water vapor was found to interfere strongly with the dynamic adsorption of /sup 133/Xe on coconut-base activated charcoal. The percent loss in the xenon adsorption coefficient was similar to values reported earlier for the adsorption of krypton on humidified charcoal. Attempts to increase the adsorption of xenon by (a) using a petroleum-based adsorbent with an extremely high surface area and (b) by impregnation of the adsorbent with iodine were not successful.

  12. Skin blood flow in sheep: comparison of xenon-133 washout and radioactive microsphere techniques

    SciTech Connect

    Midtgard, U.H.; Hales, J.R.; Fawcett, A.A.; Sejrsen, P.

    1987-09-01

    Blood flow was measured in leg and torso skin of conscious or anesthetized sheep by using 15-micron radioactive microspheres (Qm) and the /sup 133/Xe washout method (QXe). There was a good relationship between Qm in the cutaneous compartment and QXe calculated from the fast component of the biexponential washout curves (QXe = 0.40.Qm + 6.2, r = 0.90, P less than 0.001) with QXe values substantially below those determined with microspheres. Only at low blood flow levels was there a tendency for QXe to overestimate capillary blood flow as assessed with microspheres, but at higher blood flow levels the /sup 133/Xe washout method resulted in values substantially below those determined with microspheres. The slope of the slow component of the washout curves was inversely related to the tissue-blood partition coefficient in the subcutaneous tissue (r = 0.52, P less than 0.001), indicating an influence of the amount of subcutaneous fat on the washout rate. QXe calculated from the slow component of the washout curves was not significantly correlated with Qm in the subcutaneous compartment (r = 0.19, P greater than 0.10). In leg skin with dilated arteriovenous anastomoses, QXe was generally higher than in torso skin and leg skin with constricted arteriovenous anastomoses, indicating that shunt blood flow increases the washout of /sup 133/Xe.

  13. Blood flow in exercising muscles by xenon clearance and by microsphere trapping

    SciTech Connect

    Cerretelli, P.; Marconi, C.; Pendergast, D.; Meyer, M.; Heisler, N.; Piiper, J.

    1984-01-01

    The accuracy of muscle blood flow measurement by the /sup 133/Xe clearance method (Qxe) was assessed against direct venous outflow (Qv) and microsphere trapping flow (Q..mu..) determinations in isolated perfused dog gastrocnemius both at rest and during graded stimulation (O/sub 2/ consumption (Vo/sub 2/) up to 12 ml x 100 g/sup -1/ x min/sup -1/) and in the gastrocnemius, vastus lateralis, and triceps of intact dogs at rest and while running on a treadmill at varied speeds up to maximum Vo/sub 2/. In 29 measurements performed in 11 isolated muscles, Q..mu.. was in good agreement with Qv at rest and at all stimulation levels (Q..mu../Qv = 1.0 r = 0.98). /sup 133/Xe clearance yielded much lower blood flows than the venous outflow and the microsphere trapping methods. In 43 measurements in 11 muscles, the mean Qxe/Qv ratio was 0.57 +/- 0.03 (SE), independent of blood flow. Similarly, in 65 measurements in 2 intact dogs, the mean Qxe/Q..mu.. ratio in all tested muscles was 0.49 +/- 0.02 (SE), independent of blood flow. These results show that the /sup 133/Xe clearance method considerably underestimates blood flow in dog muscles.

  14. Cerebral blood flow in sickle cell cerebrovascular disease

    SciTech Connect

    Huttenlocher, P.R.; Moohr, J.W.; Johns, L.; Brown, F.D.

    1984-05-01

    Cerebral blood flow (CBF) has been studied by the xenon-133 (/sup 133/Xe) inhalation method in 16 children with suspected sickle cell cerebrovascular disease. Abnormalities consisting of decreases in total, hemispheral, or regional CBF were found in 17 of 26 studies. Eleven studies performed immediately after stroke, transient ischemic attack, or depression of state of alertness showed abnormalities. In addition to confirming regional cerebrovascular insufficiency in children with stroke due to major cerebral artery occlusion, the method detected diffuse decrease in CBF in children with stupor, coma, and seizures who had normal angiographic findings. In contrast, six of seven studies obtained after exchange transfusion or during maintenance on hypertransfusion therapy showed normal findings. The difference between results in patients with acute neurologic disturbances and those receiving transfusion therapy was statistically significant (P less than .005). The data indicate that the /sup 133/Xe method reliably demonstrates cerebrovascular impairment in sickle cell disease. They also suggest that CBF changes in patients with sickle cell disease can be reversed by exchange transfusion and by hypertransfusion therapy. The /sup 133/Xe CBF method may be useful for following up children with sickle cell disease who are at high risk for recurrent stroke.

  15. Atmospheric removal times of the aerosol-bound radionuclides 137Cs and 131I measured after the Fukushima Dai-ichi nuclear accident - a constraint for air quality and climate models

    NASA Astrophysics Data System (ADS)

    Kristiansen, N. I.; Stohl, A.; Wotawa, G.

    2012-11-01

    Caesium-137 (137Cs) and iodine-131 (131I) are radionuclides of particular concern during nuclear accidents, because they are emitted in large amounts and are of significant health impact. 137Cs and 131I attach to the ambient accumulation-mode (AM) aerosols and share their fate as the aerosols are removed from the atmosphere by scavenging within clouds, precipitation and dry deposition. Here, we estimate their removal times from the atmosphere using a unique high-precision global measurement data set collected over several months after the accident at the Fukushima Dai-ichi nuclear power plant in March 2011. The noble gas xenon-133 (133Xe), also released during the accident, served as a passive tracer of air mass transport for determining the removal times of 137Cs and 131I via the decrease in the measured ratios 137Cs/133Xe and 131I/133Xe over time. After correction for radioactive decay, the 137Cs/133Xe ratios reflect the removal of aerosols by wet and dry deposition, whereas the 131I/133Xe ratios are also influenced by aerosol production from gaseous 131I. We find removal times for 137Cs of 10.0-13.9 days and for 131I of 17.1-24.2 days during April and May 2011. The removal time of 131I is longer due to the aerosol production from gaseous 131I, thus the removal time for 137Cs serves as a better estimate for aerosol lifetime. The removal time of 131I is of interest for semi-volatile species. We discuss possible caveats (e.g. late emissions, resuspension) that can affect the results, and compare the 137Cs removal times with observation-based and modeled aerosol lifetimes. Our 137Cs removal time of 10.0-13.9 days should be representative of a "background" AM aerosol well mixed in the extratropical Northern Hemisphere troposphere. It is expected that the lifetime of this vertically mixed background aerosol is longer than the lifetime of fresh AM aerosols directly emitted from surface sources. However, the substantial difference to the mean lifetimes of AM aerosols

  16. Atmospheric removal times of the aerosol-bound radionuclides 137Cs and 131I during the months after the Fukushima Dai-ichi nuclear power plant accident - a constraint for air quality and climate models

    NASA Astrophysics Data System (ADS)

    Kristiansen, N. I.; Stohl, A.; Wotawa, G.

    2012-05-01

    Caesium-137 (137Cs) and iodine-131 (131I) are radionuclides of particular concern during nuclear accidents, because they are emitted in large amounts and are of significant health impact. 137Cs and 131I attach to the ambient accumulation-mode (AM) aerosols and share their fate as the aerosols are removed from the atmosphere by scavenging within clouds, precipitation and dry deposition. Here, we estimate their removal times from the atmosphere using a unique high-precision global measurement data set collected over several months after the accident at the Fukushima Dai-ichi nuclear power plant in March 2011. The noble gas xenon-133 (133Xe), also released during the accident, served as a passive tracer of air mass transport for determining the removal times of 137Cs and 131I via the decrease in the measured ratios 137Cs/133Xe and 131I/133Xe over time. After correction for radioactive decay, the 137Cs/133Xe ratios reflect the removal of aerosols by wet and dry deposition, whereas the 131I/133Xe ratios are also influenced by aerosol production from gaseous 131I. We find removal times for 137Cs of 10.0-13.9 days and for 131I of 17.1-24.2 days during April and May 2011. We discuss possible caveats (e.g. late emissions, resuspension) that can affect the results, and compare the 137Cs removal times with observation-based and modeled aerosol lifetimes. Our 137Cs removal time of 10.0-13.9 days should be representative of a "background" AM aerosol well mixed in the extratropical Northern Hemisphere troposphere. It is expected that the lifetime of this vertically mixed background aerosol is longer than the lifetime of AM aerosols originating from surface sources. However, the substantial difference to the mean lifetimes of AM aerosols obtained from aerosol models, typically in the range of 3-7 days, warrants further research on the cause of this discrepancy. Too short modeled AM aerosol lifetimes would have serious implications for air quality and climate model predictions.

  17. Suppression of VEGF-induced angiogenesis by the protein tyrosine kinase inhibitor, lavendustin A.

    PubMed Central

    Hu, D E; Fan, T P

    1995-01-01

    1. Vascular endothelial growth factor (VEGF) is a heparin-binding angiogenic factor which specifically acts on endothelial cells via distinct membrane-spanning tyrosine kinase receptors. Here we used the rat sponge implant model to test the hypothesis that the angiogenic activity of VEGF can be suppressed by protein tyrosine kinase (PTK) inhibitors. 2. Neovascular responses in subcutaneous sponge implants were determined by measurements of relative sponge blood flow by use of a 133Xe clearance technique, and confirmed by histological studies and morphometric analysis. 3. Daily local administration of 250 ng VEGF165 accelerated the rate of 133Xe clearance from the sponges and induced an intense neovascularisation. This VEGF165-induced angiogenesis was inhibited by daily co-administration of the selective PTK inhibitor, lavendustin A (10 micrograms), but not its negative control, lavendustin B (10 micrograms). Blood flow measurements and morphometric analysis of 8-day-old sponges showed that lavendustin A reduced the 133Xe clearance of VEGF165-treated sponges from 32.9 +/- 1.5% to 20.9 +/- 1.6% and the total fibrovascular growth area from 62.4 +/- 6.1% to 21.6 +/- 6.8% (n = 12, P < 0.05). 4. Co-injection of suramin (3 mg), an inhibitor of heparin-binding growth factors, also suppressed the VEGF165-elicited neovascular response. In contrast, neither lavendustin A nor suramin produced any effect on the basal sponge-induced angiogenesis. 5. When given alone, low doses of VEGF165 (25 ng) or basic fibroblast growth factor (bFGF; 10 ng) did not modify the basal sponge-induced neovascularisation.(ABSTRACT TRUNCATED AT 250 WORDS) Images Figure 2 Figure 2 PMID:7533611

  18. Radiation exposure to human trachea from Xenon-133 procedures

    SciTech Connect

    Prohovnik, I.; Metz, C.D.; Atkins, H.L. ||

    1995-08-01

    The general dosimetry of {sup 133}Xe for human studies is well documented, but the resultant radiation exposure to tracheal tissue is poorly known. This organ is of central relevance because the tracer is primarily eliminated through exhalation. We report actual {sup 133}Xe concentrations in respiratory air during measurement of regional cerebral blood flow (rCBF), when the tracer is administered both by inhalation and intravenous injection. Data were collected from 102 patients, with equal gender representation and an age range of 18-82 yr. Most of the patients had subarachnoid hemorrhage or Alzheimer`s disease or were normal control subjects. Average administered doses were 18 {plus_minus} 4 mCi by inhalation and 15 {plus_minus} 3 intravenously. We found average respiratory concentrations of about 1.80 mCi/liter during a 1-min inhalation and 0.74 mCi/liter following intravenous injection of standard doses. These activities drop rapidly: average respiratory concentrations during the second minute are 0.70 mCi/liter for inhalation and 0.19 mCi/liter for intravenous injection and reach negligible levels thereafter. We calculate that the tracheal absorbed dose from {sup 133}Xe procedures is approximately 28 mrad following inhalation and about 11 mrad following intravenous injection. These values reflect the full 11-min exposure, but most of the activity is only present initially. These values will agree with previous estimates and indicate an excellent safety margin. 6 refs., 2 figs., 1 tab.

  19. Computed tomographic measurement of the xenon brain-blood partition coefficient and implications for regional cerebral blood flow: a preliminary report.

    PubMed

    Kelcz, F; Hilal, S K; Hartwell, P; Joseph, P M

    1978-05-01

    The calculation of regional cerebral blood flow requires, in addition to the measurement of the clearance, a knowledge of the regional brain-blood partition coefficient. The usual 133Xe washout techniques do not measure this latter parameter but use published values for normal brain tissue. This may lead to large errors in pathological tissue because the partition coefficient changes significantly in brain tumors. Investigations have begun into the use of CT and stable xenon to produce a cross sectional view of the brain in terms of its brain-blood partition coefficients. Results of experiments using an iodine phantom and xenon inhalation in animals are presented.

  20. Method of locating a leaking fuel element in a fast breeder power reactor

    DOEpatents

    Honekamp, John R.; Fryer, Richard M.

    1978-01-01

    Leaking fuel elements in a fast reactor are identified by measuring the ratio of .sup.134 Xe to .sup.133 Xe in the reactor cover gas following detection of a fuel element leak, this ratio being indicative of the power and burnup of the failed fuel element. This procedure can be used to identify leaking fuel elements in a power breeder reactor while continuing operation of the reactor since the ratio measured is that of the gases stored in the plenum of the failed fuel element. Thus, use of a cleanup system for the cover gas makes it possible to identify sequentially a multiplicity of leaking fuel elements without shutting the reactor down.

  1. Separation of rare gases and chiral molecules by selective binding in porous organic cages

    SciTech Connect

    Chen, Linjiang; Reiss, Paul S.; Chong, Samantha Y.; Holden, Daniel; Jelfs, Kim E.; Hasell, Tom; Little, Marc A.; Kewley, Adam; Briggs, Michael E.; Stephenson, Andrew; Thomas, K. M.; Armstrong, Jayne A.; Bell, Jon; Busto, Jose; Noel, Raymond; Liu, Jian; Strachan, Denis M.; Thallapally, Praveen K.; Cooper, Andrew I.

    2014-10-31

    Abstract: The rare gases krypton, xenon, and radon pose both an economic opportunity and a potential environmental hazard. Xenon is used in commercial lighting, medical imaging, and anesthesia, and can sell for $5,000 per kilogram. Radon, by contrast, Is naturally radioactive and the second largest cause of lung cancer, and radioactive xenon, 133Xe, was a major pollutant released In the Fukushima Daiichi Nuclear Power Plant disaster. We describe an organic cage molecule that can capture xenon and radon with unprecedented selectivity, suggesting new technologies for environmental monitoring, removal of pollutants, or the recovery of rare, valuable elements from air.

  2. Evaluation of the response to xenon-133 radiations by thermoluminescent dosimeters used during the accident at Three Mile Island.

    PubMed

    Riley, R J; Zanzonico, P B; Masterson, M E; St Germain, J M; Laughlin, J S

    1982-03-01

    An evaluation is presented of the accuracy and sensitivity of three types of TLD's used during the accident at the Three Mile Island Nuclear Station. This evaluation indicated that, due to the method of calibration, all the dosimeters over-responded to 133Xe radiations. The response ranged from slightly above unity to almost two. Exposures of the TLD's were of two types, namely, the characteristic X-rays either were or were not filtered from the beam. The angular sensitivity of the dosimeters is also reported.

  3. Quantitation of countercurrent exchange during passive absorption from the dog small intestine: evidence for marked species differences in the efficiency of exchange.

    PubMed Central

    Bond, J H; Levitt, D G; Levitt, M D

    1977-01-01

    The present investigation was designed to quantitatively assess the possible influence of countercurrent exchange on passive absorption from the small intestine of the dog. Villus blood flow was measured with a modification of the microsphere method. Simultaneously, the absorption from the gut lumen of five diffusible gases (H2, He, CH4, 133Xe, and CO) was determined. Villus blood flow averaged 0.247 +/- 0.03 (SEM) ml/min per g. The observed absorption of H2, He, CH4, and 133Xe was only 16.2 +/- 1.8, 12.8 +/- 2.3, 12.0 +/- 1.8, and 15.8 +/- 1.4 %, respectively, of what this villus blood flow could carry away if it reached perfect equilibrium with the luminal gases. This low absorption rate could result from diffusion limitation to absorption or countercurrent exchange. The diffusive permeability of the barrier seperating the luminal gases and villus blood flow was assessed by measuring the absorption rate of CO. Because absorbed CO binds tightly to hemoglobin, it cannot exchange, and when present in low concentrations its uptake is entirely diffusion limited. Knowledge of the diffusion rate through tissue of the unbound gases relative to that of CO made it possible to calculate the degree to which each of the unbound gases should equilibrate with villus tip blood. The percentage equilibration between lumen and blood at the villus tip for H2, He, CH4, and 133Xe was 99.7, 99.9, 75.6, and 36.0% , respectively. Each of these values greatly exceeded the percentage equilibration of blood leaving the villus (calculated from the observed absorption rate and villus blood flow) and indicated an exchange of 83.8, 87.2, 84.1, and 56.1% of initially absorbed H2, He, CH4, and 133Xe. This result is in accord with theoretical calculations which suggest that countercurrent exchange should be exceedingly efficient in the dog. The striking effect of countercurrent exchange on passive absorption in the dog differs from our previous studies in the rabbit where no exchange was

  4. Determination of gaseous radionuclide forms in the stack air of nuclear power plants.

    PubMed

    Tecl, J; Svetlik, I

    2009-05-01

    The determination of gaseous forms of radionuclides in ventilation stacks utilising grab samples was performed as a part of independent monitoring of nuclear power plants in the Czech Republic. The activities of radionuclides (e.g. (41)Ar, (133)Xe, (135)Xe, (85m)Kr, (87)Kr, and (131m)Xe) were determined by semiconductor gamma-ray spectrometry in samples collected into pressure vessels. Radiochemical preparation of samples for determination of (14)CO(2), combustible (14)C forms, and (85)Kr was performed after the radioactive decay of radionuclides with short half-life.

  5. Acute cerebral vascular accident associated with hyperperfusion.

    PubMed

    Soin, J S; Burdine, J A

    1976-01-01

    Cerebral radionuclide angiography can demonstrate decreased or normal radioactivity in the affected region during the arterial phase in patients who have sustained a cerebral vascular accident and thus enhances the diagnostic specificity of the static brain image. In an occasional patient, however, a seemingly paradoxical pattern of regional hyperperfusion with a return to normal or subnormal perfusion following the acute phase has been observed. This phenomenon, called "luxury perfusion," has been defined using intra-arterial 133Xe for semiquantitative cerebral blood flow measurements and should be kept in mind as a potentially misleading cerebral imaging pattern.

  6. Generation of Radixenon Isotopes

    SciTech Connect

    McIntyre, Justin I.; Bowyer, Ted W.; Hayes, James C.; Heimbigner, Tom R.; Morris, Scott J.; Panisko, Mark E.; Pitts, W. K.; Pratt, Sharon L.; Reeder, Paul L.; Thomas, Charles W.

    2003-06-30

    Pacific Northwest National Laboratory has developed an automated system for separating Xe from air and can detect the following radioxenon isotopes, 131mXe, 133mXe, 133Xe, and 135Xe. This report details the techniques used to generate the various radioxenon isotopes that are used for the calibration of the detector as well as other isotopes that have the potential to interfere with the fission produced radioxenon isotopes. Fission production is covered first using highly enriched uranium followed by a description and results from an experiment to produce radioxenon isotopes from neutron activation of ambient xenon.

  7. Environmental application of stable xenon and radioxenonmonitoring

    SciTech Connect

    Dresel, P. Evan; Olsen, Khris B.; Hayes, James C.; McIntyre,Justin I.; Waichler, Scott R.; Milbrath, Brian D.; Cooper, Matt; Kennedy,B. Mack

    2006-09-05

    Characterization of transuranic waste is needed to makedecisions about waste site remediation. Soil-gas sampling for xenonisotopes can be used to define the locations of spent fuel andtransuranic wastes. Radioxenon in the subsurface is characteristic oftransuranic waste and can be measured with extreme sensitivity usinglarge-volume soilgas samples. Measurements at the Hanford Site showed133Xe and 135Xe levels indicative of 240Pu spontaneous fission. Stablexenon isotopic ratios from fission are distinct from atmospheric xenonbackground. Neutron capture by 135Xe produces an excess of 136Xe inreactor-produced xenon providing a means of distinguishing spent fuelfrom separated transuranic materials.

  8. Regional cerebral blood flow for singers and nonsingers while speaking, singing, and humming a rote passage

    SciTech Connect

    Formby, C.; Thomas, R.G.; Halsey, J.H. Jr. )

    1989-05-01

    Two groups of singers (n = 12,13) and a group of nonsingers (n = 12) each produced the national anthem by (1) speaking and (2) singing the words and by (3) humming the melody. Regional cerebral blood flow (rCBF) was measured at rest and during each phonation task from seven areas in each hemisphere by the {sup 133}Xe-inhalation method. Intrahemisphere, interhemisphere, and global rCBF were generally similar across phonation tasks and did not yield appreciable differences among the nonsingers and the singers.

  9. Regional cerebral blood flow in essential hypertension: data evaluation by a mapping system

    SciTech Connect

    Rodriguez, G.; Arvigo, F.; Marenco, S.; Nobili, F.; Romano, P.; Sandini, G.; Rosadini, G.

    1987-01-01

    Regional cerebral blood flow was studied by means of the 133Xe inhalation method in 26 untreated and 10 treated patients with essential hypertension. The untreated subjects were divided into newly and previously diagnosed groups to assess the relation between regional cerebral blood flow and the duration of hypertension. The overall flow reduction was more marked in the frontal and temporal regions in the previously diagnosed group, and this was attributed to pathological changes in the district served by the middle cerebral artery. Regional temporal lobe impairment was also noted in the newly diagnosed and treated subjects. A significant correlation was found between regional cerebral blood flow and mean arterial blood pressure.

  10. Determination of the subcutaneous tissue to blood partition coefficient in patients with severe leg ischaemia by a double isotope washout technique.

    PubMed

    Bjerre-Jepsen, K; Faris, I; Henriksen, O; Tønnesen, K H

    1982-12-01

    Knowledge of the tissue to blood partition coefficient (lambda) is essential for calculation of the perfusion coefficient in a single tissue based on measurements of the washout of locally injected isotopes. No measurements of lambda for Xenon in subcutaneous tissue in the leg have been done in patients with occlusive arterial disease. In 12 patients with occlusive arterial disease in the legs lambda for Xenon was determined in subcutaneous tissue in the calf region and foot as the ratio between the washout rate constant of 131I-Antipyrine and 133Xe. A mixture of the two indicators was injected subcutaneously laterally on the calf and in the first interosseous space on the foot. The time until the curves followed a monoexponential course varied between 15 and 45 min in the calf and 5 and 45 min in the foot. The calculated lambda for Xe showed a great variance between individuals in calf as well as foot. Mean value was 3.7 ml X g-1 (range: 1 X 7-10 X 7) in the calf and 2 X 7 ml X g-1 (range: 1 X 2-4 X 9) in the foot. It is concluded that lambda measurements are necessary for determination of subcutaneous blood flow from 133Xe washout curves in these patients. Determination of lambda is especially important when comparisons are made between individuals.

  11. Estimates of radioxenon released from Southern Hemisphere medical isotope production facilities using measured air concentrations and atmospheric transport modeling.

    PubMed

    Eslinger, Paul W; Friese, Judah I; Lowrey, Justin D; McIntyre, Justin I; Miley, Harry S; Schrom, Brian T

    2014-09-01

    The International Monitoring System (IMS) of the Comprehensive-Nuclear-Test-Ban-Treaty monitors the atmosphere for radioactive xenon leaking from underground nuclear explosions. Emissions from medical isotope production represent a challenging background signal when determining whether measured radioxenon in the atmosphere is associated with a nuclear explosion prohibited by the treaty. The Australian Nuclear Science and Technology Organisation (ANSTO) operates a reactor and medical isotope production facility in Lucas Heights, Australia. This study uses two years of release data from the ANSTO medical isotope production facility and (133)Xe data from three IMS sampling locations to estimate the annual releases of (133)Xe from medical isotope production facilities in Argentina, South Africa, and Indonesia. Atmospheric dilution factors derived from a global atmospheric transport model were used in an optimization scheme to estimate annual release values by facility. The annual releases of about 6.8 × 10(14) Bq from the ANSTO medical isotope production facility are in good agreement with the sampled concentrations at these three IMS sampling locations. Annual release estimates for the facility in South Africa vary from 2.2 × 10(16) to 2.4 × 10(16) Bq, estimates for the facility in Indonesia vary from 9.2 × 10(13) to 3.7 × 10(14) Bq and estimates for the facility in Argentina range from 4.5 × 10(12) to 9.5 × 10(12) Bq.

  12. Cerebral blood flow during paroxysmal EEG activation induced by sleep in patients with complex partial seizures

    SciTech Connect

    Gozukirmizi, E.; Meyer, J.S.; Okabe, T.; Amano, T.; Mortel, K.; Karacan, I.

    1982-01-01

    Cerebral blood flow (CBF) measurements were combined with sleep polysomnography in nine patients with complex partial seizures. Two methods were used: the 133Xe method for measuring regional (rCBF) and the stable xenon CT method for local (LCBF). Compared to nonepileptic subjects, who show diffuse CBF decreases during stages I-II, non-REM sleep onset, patients with complex partial seizures show statistically significant increases in CBF which are maximal in regions where the EEG focus is localized and are predominantly seen in one temporal region but are also propagated to other cerebral areas. Both CBF methods gave comparable results, but greater statistical significance was achieved by stable xenon CT methodology. CBF increases are more diffuse than predicted by EEG paroxysmal activity recorded from scalp electrodes. An advantage of the 133Xe inhalation method was achievement of reliable data despite movement of the head. This was attributed to the use of a helmet which maintained the probes approximated to the scalp. Disadvantages were poor resolution (7 cm3) and two-dimensional information. The advantage of stable xenon CT method is excellent resolution (80 mm3) in three dimensions, but a disadvantage is that movement of the head in patients with seizure disorders may limit satisfactory measurements.

  13. Neuropeptide Y reduces ovarian blood flow in the rabbit

    SciTech Connect

    Jorgensen, J.C.; Sejrsen, P. )

    1990-05-01

    Neuropeptide Y-containing nerve fibers have previously been demonstrated to innervate the mammalian ovary. These nerve fibers innervate primarily the vasculature. In this study we have developed a method for in vivo measurement of the ovary blood flow rate by means of the {sup 133}Xe method. Using this technique we measured the ovary blood flow rate and investigated the dose-response relationship between close intraarterial-injected NPY and the ovary blood flow rate. A monoexponential washout curve for {sup 133}Xe was found for the whole washout process, ensuring that the blood flow rate at any time could be calculated from the curve. We found a mean blood flow rate in the nonpregnant rabbit ovary at 43.6 +/- 4.4 ml.(100 g)-1.min-1 (mean +/- SEM). Injection of NPY (20, 200, 2000 pM) in the aorta close to a. ovarica resulted in a dose-dependent decrease in the ovarian blood flow rate with a maximum reduction to 40.7 +/- 6.3% (mean +/- SEM) of the control blood flow rate. These findings make it likely that receptors able to interact with NPY are present in the vasculature of the rabbit ovary.

  14. Source Term Estimation of Radioxenon Released from the Fukushima Dai-ichi Nuclear Reactors Using Measured Air Concentrations and Atmospheric Transport Modeling

    SciTech Connect

    Eslinger, Paul W.; Biegalski, S.; Bowyer, Ted W.; Cooper, Matthew W.; Haas, Derek A.; Hayes, James C.; Hoffman, Ian; Korpach, E.; Yi, Jing; Miley, Harry S.; Rishel, Jeremy P.; Ungar, R. Kurt; White, Brian; Woods, Vincent T.

    2014-01-01

    Systems designed to monitor airborne radionuclides released from underground nuclear explosions detected radioactive fallout from the Fukushima Daiichi nuclear accident in March 2011. Atmospheric transport modeling (ATM) of plumes of noble gases and particulates were performed soon after the accident to determine plausible detection locations of any radioactive releases to the atmosphere. We combine sampling data from multiple International Modeling System (IMS) locations in a new way to estimate the magnitude and time sequence of the releases. Dilution factors from the modeled plume at five different detection locations were combined with 57 atmospheric concentration measurements of 133-Xe taken from March 18 to March 23 to estimate the source term. This approach estimates that 59% of the 1.24×1019 Bq of 133-Xe present in the reactors at the time of the earthquake was released to the atmosphere over a three day period. Source term estimates from combinations of detection sites have lower spread than estimates based on measurements at single detection sites. Sensitivity cases based on data from four or more detection locations bound the source term between 35% and 255% of available xenon inventory.

  15. Xenon-133 determination of muscle blood flow: Use in evaluating cardioactive drugs

    SciTech Connect

    Wexler, J.P.; Davis, L.; Mancini, D.; Chadwick, B.; Le Jemtel, T.

    1985-05-01

    Cardioactive drugs may effect both the central and peripheral circulatory systems. The effects on the central and peripheral circulatory systems of chronic Captorpril therapy in 7 pts with severe congestive heart failure (CHF) were evaluated simultaneously. Skeletal muscle blood flow (SMBF) determined using 133-Xe washout and a Cd/Te detector, oxygen consumption (VO/sub 2/), and radial artery and femoral vein O/sub 2/ concentration difference (A-V) were determined at rest and peak upright bicycle exercise before (BT) and after (AT) 6-12 weeks of Captopril therapy. In CI pts there was a significant increase in VO/sub 2/ and SMBF AT vs BT. In contrast, in CNC pts there was no change in VO/sub 2/ and a significant decrease in SMBF AT vs BT. In pts with severe CHF who are CI, there is an apparent fall in peripheral vascular resistance (PVR). In contrast, in CNC pts there is an increase in PVR. This study demonstrates that SMBF determines using 133-Xe is an important method for determining the effects of cardioactive drugs.

  16. Cutaneous blood flow in psoriasis

    SciTech Connect

    Klemp, P.; Staberg, B.

    1983-12-01

    The disappearance rate of /sup 133/Xe was studied in 20 patients with psoriasis vulgaris, using an epicutaneous labeling technique in involved skin lesions or normal-appearing skin of the proximal extensor site of the forearm. Control experiments were performed in 10 normal subjects. Calculations of the cutaneous blood flow (CBF) in psoriatic skin lesions were performed using a tissue-to-blood partition coefficient for /sup 133/Xe, lambda c,pso, of 1.2 ml/100 g/min. lambda c,pso was estimated after the relative content of water, lipids, and proteins had been analyzed in psoriatic skin biopsies of 6 patients with untreated psoriasis. The mean relative content of water was markedly reduced to 23.5 +/- 1.5% (SEM), and lipids and proteins were markedly increased to 2.5 +/- 0.7% and 74.0 +/- 2.2, respectively, compared to previously published data for normal skin (water 72.5%, lipids 1%, proteins 26.5%). Mean CBF in untreated psoriatic skin was 63.5 +/- 9.0 ml/100 g/min. This was significantly higher than the mean CBF in 10 normal subjects, 6.3 +/- 0.5 ml/100 g/min (p much less than 0.0001). Mean CBF in normal-appearing skin in patients with psoriasis was 11.0 +/- 1.3 ml/100 g/min. This was significantly higher than CBF in normal subjects (p less than 0.0002).

  17. Adipose tissue and skeletal muscle blood flow during mental stress

    SciTech Connect

    Linde, B.; Hjemdahl, P.; Freyschuss, U.; Juhlin-Dannfelt, A.

    1989-01-01

    Mental stress (a modified Stroop color word conflict test (CWT)) increased adipose tissue blood flow (ATBF; 133Xe clearance) by 70% and reduced adipose tissue vascular resistance (ATR) by 25% in healthy male volunteers. The vasculatures of adipose tissue (abdomen as well as thigh), skeletal muscle of the calf (133Xe clearance), and the entire calf (venous occlusion plethysmography) responded similarly. Arterial epinephrine (Epi) and glycerol levels were approximately doubled by stress. Beta-Blockade by metoprolol (beta 1-selective) or propranolol (nonselective) attenuated CWT-induced tachycardia similarly. Metoprolol attenuated stress-induced vasodilation in the calf and tended to do so in adipose tissue. Propranolol abolished vasodilation in the calf and resulted in vasoconstriction during CWT in adipose tissue. Decreases in ATR, but not in skeletal muscle or calf vascular resistances, were correlated to increases in arterial plasma glycerol (r = -0.42, P less than 0.05), whereas decreases in skeletal muscle and calf vascular resistances, but not in ATR, were correlated to increases in arterial Epi levels (r = -0.69, P less than 0.01; and r = -0.43, P less than 0.05, respectively). The results suggest that mental stress increases nutritive blood flow in adipose tissue and skeletal muscle considerably, both through the elevation of perfusion pressure and via vasodilatation. Withdrawal of vasoconstrictor nerve activity, vascular beta 2-adrenoceptor stimulation by circulating Epi, and metabolic mechanisms (in adipose tissue) may contribute to the vasodilatation.

  18. Cerebral blood flow in the newborn infant: comparison of Doppler ultrasound and /sup 133/xenon clearance

    SciTech Connect

    Greisen, G.; Johansen, K.; Ellison, P.H.; Fredriksen, P.S.; Mali, J.; Friis-Hansen, B.

    1984-03-01

    Two techniques of Doppler ultrasound examination, continuous-wave and range-gated, applied to the anterior cerebral artery and to the internal carotid artery, were compared with /sup 133/xenon clearance after intravenous injection. Thirty-two sets of measurements were obtained in 16 newborn infants. The pulsatility index, the mean flow velocity, and the end-diastolic flow velocity were read from the Doppler recordings. Mean cerebral blood flow was estimated from the /sup 133/Xe clearance curves. The correlation coefficients between the Doppler and the /sup 133/Xe measurements ranged from 0.41 to 0.82. In the subset of 16 first measurements in each infant, there were no statistically significant differences between the correlation coefficients of the various Doppler ultrasound variables, but the correlation coefficients were consistently lower for the pulsatility index than for mean flow velocity or end-diastolic flow velocity, and they were consistently higher for the range-gated than for the continuous-wave Doppler technique.

  19. Evaluation of observed and modelled aerosol lifetimes using radioactive tracers of opportunity and an ensemble of 19 global models

    DOE PAGES

    Kristiansen, N. I.; Stohl, A.; Olivie, D. J. L.; ...

    2016-03-17

    Aerosols have important impacts on air quality and climate, but the processes affecting their removal from the atmosphere are not fully understood and are poorly constrained by observations. This makes modelled aerosol lifetimes uncertain. In this study, we make use of an observational constraint on aerosol lifetimes provided by radionuclide measurements and investigate the causes of differences within a set of global models. During the Fukushima Dai-Ichi nuclear power plant accident of March 2011, the radioactive isotopes cesium-137 (137Cs) and xenon-133 (133Xe) were released in large quantities. Cesium attached to particles in the ambient air, approximately according to their available aerosolmore » surface area. 137Cs size distribution measurements taken close to the power plant suggested that accumulation-mode (AM) sulfate aerosols were the main carriers of cesium. Hence, 137Cs can be used as a proxy tracer for the AM sulfate aerosol's fate in the atmosphere. In contrast, the noble gas 133Xe behaves almost like a passive transport tracer. Global surface measurements of the two radioactive isotopes taken over several months after the release allow the derivation of a lifetime of the carrier aerosol. We compare this to the lifetimes simulated by 19 different atmospheric transport models initialized with identical emissions of 137Cs that were assigned to an aerosol tracer with each model's default properties of AM sulfate, and 133Xe emissions that were assigned to a passive tracer. We investigate to what extent the modelled sulfate tracer can reproduce the measurements, especially with respect to the observed loss of aerosol mass with time. Modelled 137Cs and 133Xe concentrations sampled at the same location and times as station measurements allow a direct comparison between measured and modelled aerosol lifetime. The e-folding lifetime τe, calculated from station measurement data taken between 2 and 9 weeks after the start of the emissions, is 14.3 days (95

  20. Evaluation of observed and modelled aerosol lifetimes using radioactive tracers of opportunity and an ensemble of 19 global models

    NASA Astrophysics Data System (ADS)

    Kristiansen, N. I.; Stohl, A.; Olivié, D. J. L.; Croft, B.; Søvde, O. A.; Klein, H.; Christoudias, T.; Kunkel, D.; Leadbetter, S. J.; Lee, Y. H.; Zhang, K.; Tsigaridis, K.; Bergman, T.; Evangeliou, N.; Wang, H.; Ma, P.-L.; Easter, R. C.; Rasch, P. J.; Liu, X.; Pitari, G.; Di Genova, G.; Zhao, S. Y.; Balkanski, Y.; Bauer, S. E.; Faluvegi, G. S.; Kokkola, H.; Martin, R. V.; Pierce, J. R.; Schulz, M.; Shindell, D.; Tost, H.; Zhang, H.

    2016-03-01

    Aerosols have important impacts on air quality and climate, but the processes affecting their removal from the atmosphere are not fully understood and are poorly constrained by observations. This makes modelled aerosol lifetimes uncertain. In this study, we make use of an observational constraint on aerosol lifetimes provided by radionuclide measurements and investigate the causes of differences within a set of global models. During the Fukushima Dai-Ichi nuclear power plant accident of March 2011, the radioactive isotopes cesium-137 (137Cs) and xenon-133 (133Xe) were released in large quantities. Cesium attached to particles in the ambient air, approximately according to their available aerosol surface area. 137Cs size distribution measurements taken close to the power plant suggested that accumulation-mode (AM) sulfate aerosols were the main carriers of cesium. Hence, 137Cs can be used as a proxy tracer for the AM sulfate aerosol's fate in the atmosphere. In contrast, the noble gas 133Xe behaves almost like a passive transport tracer. Global surface measurements of the two radioactive isotopes taken over several months after the release allow the derivation of a lifetime of the carrier aerosol. We compare this to the lifetimes simulated by 19 different atmospheric transport models initialized with identical emissions of 137Cs that were assigned to an aerosol tracer with each model's default properties of AM sulfate, and 133Xe emissions that were assigned to a passive tracer. We investigate to what extent the modelled sulfate tracer can reproduce the measurements, especially with respect to the observed loss of aerosol mass with time. Modelled 137Cs and 133Xe concentrations sampled at the same location and times as station measurements allow a direct comparison between measured and modelled aerosol lifetime. The e-folding lifetime τe, calculated from station measurement data taken between 2 and 9 weeks after the start of the emissions, is 14.3 days (95

  1. Evaluation of observed and modelled aerosol lifetimes using radioactive tracers of opportunity and an ensemble of 19 global models

    NASA Astrophysics Data System (ADS)

    Kristiansen, N. I.; Stohl, A.; Olivié, D. J. L.; Croft, B.; Søvde, O. A.; Klein, H.; Christoudias, T.; Kunkel, D.; Leadbetter, S. J.; Lee, Y. H.; Zhang, K.; Tsigaridis, K.; Bergman, T.; Evangeliou, N.; Wang, H.; Ma, P.-L.; Easter, R. C.; Rasch, P. J.; Liu, X.; Pitari, G.; Di Genova, G.; Zhao, S. Y.; Balkanski, Y.; Bauer, S. E.; Faluvegi, G. S.; Kokkola, H.; Martin, R. V.; Pierce, J. R.; Schulz, M.; Shindell, D.; Tost, H.; Zhang, H.

    2015-09-01

    Aerosols have important impacts on air quality and climate, but the processes affecting their removal from the atmosphere are not fully understood and are poorly constrained by observations. This makes modelled aerosol lifetimes uncertain. In this study, we make use of an observational constraint on aerosol lifetimes provided by radionuclide measurements and investigate the causes of differences within a set of global models. During the Fukushima Dai-Ichi nuclear power plant accident of March 2011, the radioactive isotopes cesium-137 (137Cs) and xenon-133 (133Xe) were released in large quantities. Cesium attached to particles in the ambient air, approximately according to their available aerosol surface area. 137Cs size distribution measurements taken close to the power plant suggested that accumulation-mode (AM) sulphate aerosols were the main carriers for the cesium. Hence, 137Cs can be used as a proxy tracer for the AM sulphate aerosol's fate in the atmosphere. In contrast, the noble gas 133Xe behaves almost like a passive transport tracer. Global surface measurements of the two radioactive isotopes taken over several months after the release allow the derivation of a lifetime of the carrier aerosol. We compare this to the lifetimes simulated by 19 different atmospheric transport models initialized with identical emissions of 137Cs that were assigned to an aerosol tracer with each model's default properties of AM sulphate, and 133Xe emissions that were assigned to a passive tracer. We investigate to what extent the modelled sulphate tracer can reproduce the measurements, especially with respect to the observed loss of aerosol mass with time. Modelled 37Cs and 133Xe concentrations sampled at the same location and times as station measurements allow a direct comparison between measured and modelled aerosol lifetime. The e-folding lifetime τe, calculated from station measurement data taken between two and nine weeks after the start of the emissions, is 14.3 days

  2. Xenon-133 and caesium-137 releases into the atmosphere from the Fukushima Dai-ichi nuclear power plant: determination of the source term, atmospheric dispersion, and deposition

    NASA Astrophysics Data System (ADS)

    Stohl, A.; Seibert, P.; Wotawa, G.; Arnold, D.; Burkhart, J. F.; Eckhardt, S.; Tapia, C.; Vargas, A.; Yasunari, T. J.

    2012-03-01

    On 11 March 2011, an earthquake occurred about 130 km off the Pacific coast of Japan's main island Honshu, followed by a large tsunami. The resulting loss of electric power at the Fukushima Dai-ichi nuclear power plant developed into a disaster causing massive release of radioactivity into the atmosphere. In this study, we determine the emissions into the atmosphere of two isotopes, the noble gas xenon-133 (133Xe) and the aerosol-bound caesium-137 (137Cs), which have very different release characteristics as well as behavior in the atmosphere. To determine radionuclide emissions as a function of height and time until 20 April, we made a first guess of release rates based on fuel inventories and documented accident events at the site. This first guess was subsequently improved by inverse modeling, which combined it with the results of an atmospheric transport model, FLEXPART, and measurement data from several dozen stations in Japan, North America and other regions. We used both atmospheric activity concentration measurements as well as, for 137Cs, measurements of bulk deposition. Regarding 133Xe, we find a total release of 15.3 (uncertainty range 12.2-18.3) EBq, which is more than twice as high as the total release from Chernobyl and likely the largest radioactive noble gas release in history. The entire noble gas inventory of reactor units 1-3 was set free into the atmosphere between 11 and 15 March 2011. In fact, our release estimate is higher than the entire estimated 133Xe inventory of the Fukushima Dai-ichi nuclear power plant, which we explain with the decay of iodine-133 (half-life of 20.8 h) into 133Xe. There is strong evidence that the 133Xe release started before the first active venting was made, possibly indicating structural damage to reactor components and/or leaks due to overpressure which would have allowed early release of noble gases. For 137Cs, the inversion results give a total emission of 36.6 (20.1-53.1) PBq, or about 43% of the estimated

  3. Subcutaneous blood flow in psoriasis

    SciTech Connect

    Klemp, P.

    1985-03-01

    The simultaneously recorded disappearance rates of /sup 133/xe from subcutaneous adipose tissue in the crus were studied in 10 patients with psoriasis vulgaris using atraumatic labeling of the tissue in lesional skin (LS) areas and symmetrical, nonlesional skin (NLS) areas. Control experiments were performed bilaterally in 10 younger, healthy subjects. The subcutaneous washout rate constant was significantly higher in LS, 0.79 +/- 0.05 min-1 x 10(2) compared to the washout rate constant of NLS, 0.56 +/- 0.07 min-1. 10(2), or the washout rate constant in the normal subjects, 0.46 +/- 0.17 min-1 x 10(2). The mean washout rate constant in NLS was 25% higher than the mean washout rate constant in the normal subjects. The difference was, however, not statistically significant. Differences in the washout rate constants might be due to abnormal subcutaneous tissue-to-blood partition (lambda) in the LS--and therefore not reflecting the real differences in the subcutaneous blood flow (SBF). The lambda for /sup 133/Xe was therefore measured--using a double isotope washout method (/sup 133/Xe and (/sup 131/I)antipyrine)--in symmetrical sites of the lateral crus in LS and NLS of 10 patients with psoriasis vulgaris and in 10 legs of normal subjects. In LS the lambda was 4.52 +/- 1.67 ml/g, which was not statistically different from that of NLS, 5.25 +/- 2.19 ml/g, nor from that of normal subcutaneous tissue, 4.98 +/- 1.04 ml/g. Calculations of the SBF using the obtained lambda values gave a significantly higher SBF in LS, 3.57 +/- 0.23 ml/100 g/min, compared to SBF in the NLS, 2.94 +/- 0.37 ml/100 g/min. There was no statistically significant difference between SBF in NLS and SBF in the normal subjects. The increased SBF in LS of psoriatics might be a secondary phenomenon to an increased heat loss in the lesional skin.

  4. Monte Carlo simulations of NaI(Tl) spectra for measurements of semi-infinite plumes.

    PubMed

    Korpach, Ed; Mekarski, Pawel; Ungar, R Kurt

    2014-08-01

    For the past 10 y Health Canada has operated a Fixed Point Surveillance Network of NaI(Tl) detectors across Canada. Deployed for both emergency response and daily monitoring of airborne radiation in the environment, a spectral stripping method allowed measurement of certain isotopes well below the ambient dose rate. These include (133)Xe, (135)Xe and (41)Ar, typical of emissions from operating nuclear reactors. In an effort to increase the number of isotopes measured at these low levels a new technique of spectral fitting using spectral templates is being implemented. However, this requires very accurate spectral templates that can be difficult or impossible to obtain empirically for environmental measurements of airborne radio-isotopes. Therefore, a method of efficiently using Monte Carlo techniques to create these templates was developed.

  5. An automated ionization chamber for secondary radioactivity standards.

    PubMed

    Fitzgerald, R

    2010-01-01

    I report on the operation and characterization of a new ionization chamber system, "AUTOIC", featuring a commercial digital electrometer and a commercial robotic sample changer. The relative accuracy of the electrometer was improved significantly beyond the manufacturer's specifications through an in-house calibration of the various ranges, applied via software. The measurement precision and repeatability of the system have been determined by measuring multiple samples of the same radionuclide over the span of two or three years. The linearity of the system was examined by following the decay of (99m)Tc, (99)Mo and (133)Xe sources for up to 19 half-lives and determining half-life values. All of these values agree with the accepted literature values, within their combined uncertainties.

  6. New noninvasive quantitative assessment of cerebral blood flow using N-isopropyl-(iodine 123)p-iodoamphetamine

    SciTech Connect

    Matsuda, H.; Higashi, S.; Tsuji, S.; Seki, H.; Sumiya, H.; Fujii, H.; Oba, H.; Terada, H.; Imai, K.; Tonami, N.

    1987-01-01

    The use of a nomogram is described as a new noninvasive quantitative assessment of cerebral blood flow using N-isopropyl-(/sup 123/I)p-iodoamphetamine (IMP) and single-photon emission computed tomography. The nomogram was constructed from a computer analysis of the flow value relative to varying washout rate of brain activities between early and late tomographic images, and partition coefficient between brain tissue and blood. The validity of this method was evaluated in normal volunteers and in patients with cerebrovascular disorders by comparing the cortical flow values (Y) estimated from the IMP-nomogram with initial slope indices (X) by the /sup 133/Xe inhalation method. A significant correlation (N = 42, r = 0.88, P less than .001) was demonstrated between them, and the regression line was Y = 1.6X-7. A development and confirmation of this method made it possible to measure flow values noninvasively with the use of IMP.

  7. A new noninvasive quantitative assessment of cerebral blood flow using N-isopropyl-(iodine 123)p-iodoamphetamine.

    PubMed

    Matsuda, H; Higashi, S; Tsuji, S; Seki, H; Sumiya, H; Fujii, H; Oba, H; Terada, H; Imai, K; Tonami, N

    1987-01-01

    The use of a nomogram is described as a new noninvasive quantitative assessment of cerebral blood flow using N-isopropyl-(123I)p-iodoamphetamine (IMP) and single-photon emission computed tomography. The nomogram was constructed from a computer analysis of the flow value relative to varying washout rate of brain activities between early and late tomographic images, and partition coefficient between brain tissue and blood. The validity of this method was evaluated in normal volunteers and in patients with cerebrovascular disorders by comparing the cortical flow values (Y) estimated from the IMP-nomogram with initial slope indices (X) by the 133Xe inhalation method. A significant correlation (N = 42, r = 0.88, P less than .001) was demonstrated between them, and the regression line was Y = 1.6X-7. A development and confirmation of this method made it possible to measure flow values noninvasively with the use of IMP.

  8. Cerebral blood flow asymmetries in headache-free migraineurs

    SciTech Connect

    Levine, S.R.; Welch, K.M.; Ewing, J.R.; Joseph, R.; D'Andrea, G.

    1987-11-01

    Regional cerebral blood flow (rCBF) asymmetries were studied in controls and patients with common and classic/complicated migraine using /sup 133/Xe inhalation with 8 homologously situated external collimators over each cerebral hemisphere. Migraine patients as a group more frequently had posterior rCBF asymmetries than controls (p less than 0.03). Although there were no differences in the number of anterior rCBF asymmetries, migraine patients had 2 or more asymmetric probe pairs more often than controls (p less than 0.02). The posterior rCBF asymmetries, consistent with the site of activation of many migraine attacks, may be related to more labile control of the cerebral circulation.

  9. Global radioxenon emission inventory based on nuclear power reactor reports.

    PubMed

    Kalinowski, Martin B; Tuma, Matthias P

    2009-01-01

    Atmospheric radioactivity is monitored for the verification of the Comprehensive Nuclear-Test-Ban Treaty, with xenon isotopes 131mXe, 133Xe, 133mXe and 135Xe serving as important indicators of nuclear explosions. The treaty-relevant interpretation of atmospheric concentrations of radioxenon is enhanced by quantifying radioxenon emissions released from civilian facilities. This paper presents the first global radioxenon emission inventory for nuclear power plants, based on North American and European emission reports for the years 1995-2005. Estimations were made for all power plant sites for which emission data were unavailable. According to this inventory, a total of 1.3PBq of radioxenon isotopes are released by nuclear power plants as continuous or pulsed emissions in a generic year.

  10. Production and release rate of (37)Ar from the UT TRIGA Mark-II research reactor.

    PubMed

    Johnson, Christine; Biegalski, Steven R; Artnak, Edward J; Moll, Ethan; Haas, Derek A; Lowrey, Justin D; Aalseth, Craig E; Seifert, Allen; Mace, Emily K; Woods, Vincent T; Humble, Paul

    2017-02-01

    Air samples were taken at various locations around The University of Texas at Austin's TRIGA Mark II research reactor and analyzed to determine the concentrations of (37)Ar, (41)Ar, and (133)Xe present. The measured ratio of (37)Ar/(41)Ar and historical records of (41)Ar releases were then utilized to estimate an annual average release rate of (37)Ar from the reactor facility. Using the calculated release rate, atmospheric transport modeling was performed in order to determine the potential impact of research reactor operations on nearby treaty verification activities. Results suggest that small research reactors (∼1 MWt) do not release (37)Ar in concentrations measurable by currently proposed OSI detection equipment.

  11. SPECT study of regional cerebral blood flow in Alzheimer disease

    SciTech Connect

    Bonte, F.J.; Ross, E.D.; Chehabi, H.H.; Devous, M.D. Sr.

    1986-07-01

    A common cause of dementia in late midlife and old age is Alzheimer disease (AD), which affects more than one in 20 individuals over the age of 65. Past studies of regional cerebral blood flow (rCBF) in patients with AD here suggested blood flow abnormalities, but findings have differed. We have studied 37 patients diagnosed as having AD with inhalation and washout of /sup 133/Xe and single-photon emission computed tomography (SPECT), obtaining evidence of abnormal rCBF patterns in 19. Flow reductions were most common in the temporoparietal regions and were occasionally found in the frontal areas. Investigators using positron-emission tomography (PET) have identified similar findings with respect to rCBF and regional oxygen, glucose, and protein metabolism. The SPECT determination of rCBF, which gives information similar to that provided by PET, may assume importance in the diagnosis of AD and in the differential diagnosis of the dementias.

  12. Occult pulmonary embolism: a common occurrence in deep venous thrombosis

    SciTech Connect

    Dorfman, G.S.; Cronan, J.J.; Tupper, T.B.; Messersmith, R.N.; Denny, D.F.; Lee, C.H.

    1987-02-01

    Ventilation-perfusion scans were used in a prospective study to determine the prevalence of occult pulmonary embolus in proven deep venous thrombosis. Fifty-eight patients without symptoms of pulmonary embolism, but with venographically proven deep venous thrombosis, were subjected to chest radiographs, /sup 99m/Tc macroaggregated-albumin perfusion scans, and /sup 133/Xe ventilation scans. Of the 49 patients with deep venous thrombosis proximal to the calf veins, 17 (35%) had high-probability scans. Of all 58 patients, only 12 (21%) had normal scans. When the study population was compared with a group of 430 patients described in reports of pulmonary perfusion in asymptomatic persons, a significantly higher percentage of high-probability scans was found in the study population with deep venous thrombosis. Baseline ventilation-perfusion lung scanning is valuable for patients with proven above-knee deep venous thrombosis.

  13. Xenon-133 and caesium-137 releases into the atmosphere from the Fukushima Dai-ichi nuclear power plant: determination of the source term, atmospheric dispersion, and deposition

    NASA Astrophysics Data System (ADS)

    Stohl, A.; Seibert, P.; Wotawa, G.; Arnold, D.; Burkhart, J. F.; Eckhardt, S.; Tapia, C.; Vargas, A.; Yasunari, T. J.

    2012-04-01

    This presentation will show the results of a paper currently under review in ACPD and some additional new results, including more data and with an independent box modeling approach to support some of the findings of the ACPD paper. On 11 March 2011, an earthquake occurred about 130 km off the Pacific coast of Japan's main island Honshu, followed by a large tsunami. The resulting loss of electric power at the Fukushima Dai-ichi nuclear power plant (FD-NPP) developed into a disaster causing massive release of radioactivity into the atmosphere. In this study, we determine the emissions of two isotopes, the noble gas xenon-133 (133Xe) and the aerosol-bound caesium-137 (137Cs), which have very different release characteristics as well as behavior in the atmosphere. To determine radionuclide emissions as a function of height and time until 20 April, we made a first guess of release rates based on fuel inventories and documented accident events at the site. This first guess was subsequently improved by inverse modeling, which combined the first guess with the results of an atmospheric transport model, FLEXPART, and measurement data from several dozen stations in Japan, North America and other regions. We used both atmospheric activity concentration measurements as well as, for 137Cs, measurements of bulk deposition. Regarding 133Xe, we find a total release of 16.7 (uncertainty range 13.4-20.0) EBq, which is the largest radioactive noble gas release in history not associated with nuclear bomb testing. There is strong evidence that the first strong 133Xe release started early, before active venting was performed. The entire noble gas inventory of reactor units 1-3 was set free into the atmosphere between 11 and 15 March 2011. For 137Cs, the inversion results give a total emission of 35.8 (23.3-50.1) PBq, or about 42% of the estimated Chernobyl emission. Our results indicate that 137Cs emissions peaked on 14-15 March but were generally high from 12 until 19 March, when they

  14. Modelling the global atmospheric transport and deposition of radionuclides from the Fukushima Dai-ichi nuclear accident.

    NASA Astrophysics Data System (ADS)

    Christoudias, Theodoros; Lelieveld, Jos

    2013-04-01

    We modeled the global atmospheric dispersion and deposition of radionuclides released from the Fukushima Dai-ichi nuclear power plant accident. The EMAC atmospheric chemistry - general circulation model was used, with circulation dynamics nudged towards ERA-Interim reanalysis data. We applied a resolution of approximately 0.5 degrees in latitude and longitude (T255). The model accounts for emissions and transport of the radioactive isotopes 131I and 137Cs, and removal processes through precipitation, particle sedimentation and dry deposition. In addition, we simulated the release of 133Xe, a noble gas that can be regarded as a passive transport tracer of contaminated air. The source terms are based on Chino et al. (2011) and Stohl et al. (2012); especially the emission estimates of 131I are associated with a high degree of uncertainty. The calculated concentrations have been compared to station observations by the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO).

  15. Cerebral Blood Flow Estimation Using Classification Techniques On A Sequence Of Low Resolution Tomographic Evolutive Images

    NASA Astrophysics Data System (ADS)

    Chan, Marie; Aguilar-Martin, Joseph; Boulanouar, Kader; Celsis, Pierre; Marc-Vergnes, Jean P.

    1989-05-01

    In order to improve the performance of the instrumental variable method (IVM) in calculating regional cerebral blood flow (rCBF) using Single Photon Emission Computed Tomography (SPELT), and inert diffusible tracer such as 133Xe, we use Learning Algorithms for Multivariate Data Analysis (LAMDA) to classify the voxels of the images of local concentrations in the brain. The LAMDA method correctly distinguished between extra and intra-cerebral voxels. However the topography of the intra-cerebral classes did not match the Regions Of Interest (ROI) defined on an anatomical basis. Provided that all the intra-cerebral classes contaminated by bone and air passage artefact were rejected, the results given by the NM are in good agreement with those derived by the bolus distribution principle. We thus conclude that LAMDA methods can improve the reliability of images of CBF estimates.

  16. Radioxenon detector calibration spike production and delivery systems

    SciTech Connect

    Foxe, Michael P.; Cameron, Ian M.; Cooper, Matthew W.; Haas, Derek A.; Hayes, James C.; Kriss, Aaron A.; Lidey, Lance S.; Mendez, Jennifer M.; Prinke, Amanda M.; Riedmann, Robin A.

    2016-03-01

    Abstract Beta-Gamma coincidence radioxenon detectors must be calibrated for each of the four-radioxenon isotopes (135Xe, 133Xe, 133mXe, and 131mXe). Without a proper calibration, there is potential for the misidentification of the amount of each isotope detected. It is important to accurately determine the amount of each radioxenon isotope, as the ratios can be used to distinguish between an anthropogenic source and a nuclear explosion. We have developed a xenon calibration system (XeCalS) that produces calibration spikes of known activity and pressure for field calibration of detectors. The activity concentrations of these calibration spikes are measured using a beta-gamma coincidence detector and a high purity germanium (HPGe) detector. We will present the results from the development and commissioning of XeCalS, along with the future plans for a portable spike implementation system.

  17. Potential impact of releases from a new Molybdenum-99 production facility on regional measurements of airborne xenon isotopes

    SciTech Connect

    Bowyer, Ted W.; Eslinger, Paul W.; Cameron, Ian M.; Friese, Judah I.; Hayes, James C.; Metz, Lori A.; Miley, Harry S.

    2014-03-01

    The monitoring of the radioactive xenon isotopes 131mXe, 133Xe, 133mXe, and 135Xe is important for the detection of nuclear explosions. While backgrounds of the xenon isotopes are short-lived, they are constantly replenished from activities dominated by the fission-based production of 99Mo used for medical procedures. One of the most critical locations on earth for the monitoring of nuclear explosions is the Korean peninsula, where the Democratic Republic of North Korea (DPRK) has announced that it had conducted three nuclear tests between 2009 and 2013. This paper explores the backgrounds that would be caused by the medium to large scale production of 99Mo in the region of the Korean peninsula.

  18. Normal pressure hydrocephalus. Influences on cerebral hemodynamic and cerebrospinal fluid pressure--chemical autoregulation

    SciTech Connect

    Meyer, J.S.; Tachibana, H.; Hardenberg, J.P.; Dowell, R.E. Jr.; Kitagawa, Y.; Mortel, K.F.

    1984-02-01

    Blood flow in the cerebral gray matter was measured in normal pressure hydrocephalus and Alzheimer disease by 133Xe inhalation. Flow values in the frontal and temporal gray matter increased after lowering cerebrospinal fluid (CSF) pressure by lumbar puncture in normal pressure hydrocephalus (p less than 0.05) and also after shunting. One case with cerebral complications did not improve clinically. In Alzheimer disease the reverse (decreases in flow in the gray matter) occurred after removal of CSF. Normal pressure hydrocephalus was associated with impaired cerebral vasomotor responsiveness during 100% oxygen and 5% carbon dioxide inhalation. This complication was restored toward normal after CSF removal and/or shunting. Cerebral blood flow measurements appear to be useful for confirming the diagnosis of normal pressure hydrocephalus and predicting the clinical benefit from shunting.

  19. Normal pressure hydrocephalus. Influences on cerebral hemodynamic and cerebrospinal fluid pressure--chemical autoregulation.

    PubMed

    Meyer, J S; Tachibana, H; Hardenberg, J P; Dowell, R E; Kitagawa, Y; Mortel, K F

    1984-02-01

    Blood flow in the cerebral gray matter was measured in normal pressure hydrocephalus and Alzheimer disease by 133Xe inhalation. Flow values in the frontal and temporal gray matter increased after lowering cerebrospinal fluid (CSF) pressure by lumbar puncture in normal pressure hydrocephalus (p less than 0.05) and also after shunting. One case with cerebral complications did not improve clinically. In Alzheimer disease the reverse (decreases in flow in the gray matter) occurred after removal of CSF. Normal pressure hydrocephalus was associated with impaired cerebral vasomotor responsiveness during 100% oxygen and 5% carbon dioxide inhalation. This complication was restored toward normal after CSF removal and/or shunting. Cerebral blood flow measurements appear to be useful for confirming the diagnosis of normal pressure hydrocephalus and predicting the clinical benefit from shunting.

  20. Radioxenon detections in the CTBT International Monitoring System likely related to the announced nuclear test in North Korea conducted on February 12, 2013

    SciTech Connect

    Ringbom, Anders; Axelssson, A.; Aldener, M.; Auer, M.; Bowyer, Ted W.; Fritioff, T.; Hoffman, Ian; Khrustalev, Kirill; Nikkinen, Mika; Popov, Vladimir Y.; Popov, Y.; Ungar, R. Kurt; Wotawa, G.

    2014-02-01

    Abstract: Observations of the radioxenon isotopes 133Xe and 131mXe collected at the IMS stations RN38 and RN58 on April 7-8, and April 12-13 2013, respectively, are unique with respect to the measurement history of these stations. Comparison of measured data with calculated isotopic ratios as well as analysis using atmospheric transport modeling indicate that it is likely that the xenon measured was created in the underground nuclear test conducted by North Korea on February 12, 2013, and released 7 weeks later. More than one release is required to explain all observations. The 131mXe source terms for each release were calculated to 7x1011 Bq, corresponding to about 1-10% of the total xenon inventory for a 10-kt explosion, depending on fractionation and release scenario. The observed ratios could not be used to obtain any information regarding the fissile material that was used in the test.

  1. Probing the Strength of Nuclear-Plasma Interactions at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Ratkiewicz, A.; Berzak Hopkins, L.; Bleuel, D. L.; Cassata, W. S.; London, R.; Velsko, C. A.; Yeamans, C. B.; Bernstein, L. A.; van Bibber, K.; Goldblum, B. L.; Siem, S.; Weideking, M.

    2016-09-01

    Electron-mediated interactions between nuclei and plasma are expected to affect nuclear reaction cross sections in High Energy Density Plasmas (HEDPs), which are the environment in which stellar nucleosynthesis occurs. However, attempts to measure the strength of these Nuclear Plasma Interactions (NPIs) have been hindered by the extreme narrowness of the nuclear transition (Γ <= 1 μeV). We report on the planned effort to measure the strength of this effect in HEDPs to be produced at the National Ignition Facility (NIF) by inducing NPIs on highly-excited (1-5 MeV) nuclear states of 133Xe produced in the (n,2n) reaction with 134Xe in the NIF target. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  2. Regional cerebral blood flow and anxiety: a correlation study in neurologically normal patients

    SciTech Connect

    Rodriguez, G.; Cogorno, P.; Gris, A.; Marenco, S.; Mesiti, C.; Nobili, F.; Rosadini, G.

    1989-06-01

    Regional CBF (rCBF) was evaluated by the /sup 133/Xe inhalation method in 60 neurologically normal patients (30 men and 30 women) and hemispheric and regional values were correlated with anxiety measurements collected by a self-rating questionnaire before and after the examination. Statistically significant negative correlations between rCBF and anxiety measures were found. rCBF reduction for high anxiety levels is in line with results previously reported by others and could be related to lower performance levels for moderately high anxiety scores as those reported in the present population. This could perhaps be explained by rearrangement of flow from cortical zones to deeper areas of the brain, classically known to be implicated in the control of emotions. However, these results should be interpreted cautiously, since they were obtained in patients and not in normal subjects.

  3. Regional pulmonary ventilation and perfusion distribution in patients with untreated idiopathic scoliosis

    PubMed Central

    Bake, B.; Bjure, J.; Kasalichý, J.; Nachemson, A.

    1972-01-01

    Regional lung function using xenon-133 was studied in 45 seated patients aged 11 to 78 years with untreated idiopathic scoliosis and angulation of curvature between 10 and 190°. Perfusion distribution was assessed by intravenous bolus injection of 133Xe and distribution of ventilation to volume ratios by washouts after inhalation and intravenous injection. No consistent differences between the lungs on the convex and concave sides of the curvature were found. The lung bases were found to be more severely affected than the apices, perfusion and ventilation being progressively reduced with increasing deformity. There was evidence of inhomogeneity within regions and it is suggested that in younger patients the ventilation and perfusion within regions are better matched than in older patients. PMID:4647630

  4. INGAS: Iranian Noble Gas Analyzing System for radioxenon measurement

    NASA Astrophysics Data System (ADS)

    Doost-Mohammadi, V.; Afarideh, H.; Etaati, G. R.; Safari, M. J.; Rouhi, H.

    2016-03-01

    In this article, Iranian Noble Gas Analyzing System (INGAS) will be introduced. This system is based on beta-gamma coincidence technique and consists of a well-type NaI(Tl) as gamma or X radiation detector and a cylindrical plastic scintillator to detect beta or conversion electron. Standard NIM modules were utilized to detect coincidence events of detectors. Both the beta and gamma detectors were appropriately calibrated. The efficiency curve of gamma detector for volume geometry was obtained by comparing the results of gamma point sources measurements and simulations of GATE V7.0 Monte Carlo code. The performance of detection system was checked by injection of 222Rn and 131mXe gaseous source in the detection cell. The minimum detectable activity of the system for 133Xe is 1.240±0.024 mBq for 24 h measurement time.

  5. Local variation in cutaneous and subcutaneous blood flow measured by CdTe(C1) minidetectors in normal and psoriatic skin

    SciTech Connect

    Klemp, P.; Bojsen, J.

    1986-02-01

    The accuracy of the /sup 133/Xe washout method and the validity of newly developed cadmium telluride CdTe(Cl) minisemiconductor detectors were estimated by performing comparative, simultaneous measurements of both cutaneous (CBF) and subcutaneous (SBF) blood flow using 2 conventional scintillation sodium iodide NaI(Tl) and CdTe(Cl) detectors over the same radioactive depot in each of 10 individuals. The accuracy of the /sup 133/Xe washout method was found to be 13-15% (C.V.) for the CBF measurements and 9-12% (C.V.) for the SBF measurements. The CdTe(Cl) detectors, which have a weight of 20 g and were attached directly over the radioactive depot, may replace stationary NaI(Tl) detectors placed 20 cm from the depot for measurements of both CBF and SBF. Two CdTe(Cl) detectors were used for estimations of the local variation in CBF and SBF within a distance of 5 cm in normal skin of 10 individuals. The C.V. was 7% for the CBF measurements and 18% for the SBF measurements. Measurements of CBF and SBF were performed in 6 psoriatic patients who developed typical Woronoff rings. The local CBF differed significantly from the center of psoriatic plaques to the margin, in the Woronoff ring, and in nonlesional skin. In contrast, SBF was remarkably equal within the plaque and in the Woronoff ring. Cutaneous blood flow in chronic stable, lesional psoriatic skin was significantly lower than previously published values for active lesional psoriatic skin, but significantly higher than CBF in normal individuals. Measurements of CBF in tetrahydrofurfuryl nicotinic acid (Trafuril)-treated skin showed higher values than measurements of CBF in the postischemic hyperemia period both in normal and in lesional psoriatic skin. Trafuril induced a significant increase of CBF in both lesional and nonlesional skin.

  6. High frequency jet ventilation and intermittent positive pressure ventilation. Effect of cerebral blood flow in patients after open heart surgery

    SciTech Connect

    Pittet, J.F.; Forster, A.; Suter, P.M. )

    1990-02-01

    Attenuation of ventilator-synchronous pressure fluctuations of intracranial pressure has been demonstrated during high frequency ventilation in animal and human studies, but the consequences of this effect on cerebral blood flow have not been investigated in man. We compared the effects of high frequency jet ventilation and intermittent positive pressure ventilation on CBF in 24 patients investigated three hours after completion of open-heart surgery. The patients were investigated during three consecutive periods with standard sedation (morphine, pancuronium): a. IPPV; b. HFJV; c. IPPV. Partial pressure of arterial CO{sub 2} (PaCO{sub 2}: 4.5-5.5 kPa) and rectal temperature (35.5 to 37.5{degree}C) were maintained constant during the study. The CBF was measured by intravenous {sup 133}Xe washout technique. The following variables were derived from the cerebral clearance of {sup 133}Xe: the rapid compartment flow, the initial slope index, ie, a combination of the rapid and the slow compartment flows, and the ratio of fast compartment flow over total CBF (FF). Compared to IPPV, HFJV applied to result in the same mean airway pressure did not produce any change in pulmonary gas exchange, mean systemic arterial pressure, and cardiac index. Similarly, CBF was not significantly altered by HFJV. However, important variations of CBF values were observed in three patients, although the classic main determinants of CBF (PaCO{sub 2}, cerebral perfusion pressure, Paw, temperature) remained unchanged. Our results suggest that in patients with normal systemic hemodynamics, the effects of HFJV and IPPV on CBF are comparable at identical levels of mean airway pressure.

  7. Evaluation of environmental radioxenon isotopical signals from a singular large source emitter

    NASA Astrophysics Data System (ADS)

    Saey, P. R. J.; Bowyer, T. W.; Aldener, M.; Becker, A.; Cooper, M. W.; Elmgren, K.; Faanhof, A.; Hayes, J. C.; Hosticka, B.; Lidey, L. S.

    2009-04-01

    In the framework of the verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) the atmospheric background of environmental radioxenon is been studied near areas that could be affected by man-made sources. It was recently shown that radiopharmaceutical facilities (RPF) make a major contribution to the general background of 133Xe and other xenon isotopes both in the northern and southern hemisphere. The daily IMS noble gas measurements around the globe are influenced from such anthropogenic sources that could mask radioxenon signals from a nuclear explosion. To distinguish a nuclear explosion signal from releases from civil nuclear facilities, not only the activity concentration but also the ratio of different radioxenon isotopes (131mXe, 133mXe, 133Xe and 135Xe) plays a crucial role, since the ratios can be used to discriminate source types. Theoretical release and ratio studies were recently published, but no measurements close to radiopharmaceutical facilities have ever been performed. The world's fourth largest radiopharmaceutical facility, NTP Radioisotopes Ltd, is located in Pelindaba, South Africa. Other than a small nuclear power plant, located 1300 km southwest, near Cape Town and a small research reactor in the DR of Congo, located 2700 km northwest, this is the only facility that is known to emit any radioxenon on the African continent south of the Equator. This source is likely very dominant with respect to xenon emission. This makes it a point source, which is a unique situation, as all other worldwide large radiopharmaceutical facilities are situated in regions surrounded by many other nuclear facilities. Between 10 November and 22 December 2008, radioxenon was measured continuously with a radioactive xenon measurement system, at the North-West University, Mafikeng, South Africa, which is situated 250 km northwest of Pelindaba. Fifty-six 12-hour samples were measured with a beta-gamma coincidence detector, of which 55 contained 133Xe with

  8. Environmental characterisation of a major radioxenon source in Europe

    NASA Astrophysics Data System (ADS)

    Saey, P. R. J.; Ringbom, A.; Becker, A.; Camps, J.; Paquet, N.; Sonck, M.; Taffary, T.; van der Meer, K.; Verboomen, B.; Zähringer, M.

    2009-04-01

    In the framework of the verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) the atmospheric background of environmental radioxenon has been studied. It was recently shown that radiopharmaceutical facilities (RPF) have a major contribution to the general background of 133Xe and other xenon isotopes both in the northern and southern hemisphere. The daily International Monitoring System (IMS) noble gas measurements around the globe are influenced from such anthropogenic sources that could hide relevant radioxenon signals. To distinguish a nuclear explosion from releases from civil nuclear facilities, not only the activity concentration but also the ratio of different radioxenon isotopes (131mXe, 133mXe, 133Xe and 135Xe) plays a crucial role, since the ratios can be used to discriminate source types. Theoretical release and ratio studies were recently published, but no high-sensitive measurements in and close to radiopharmaceutical facilities have ever been performed. During the summer of 2008, a three week field campaign was carried out in the region around the Belgian radiopharmaceutical facility IRE in Fleurus, the world third largest one. The scope was to obtain the activity concentration of the releases and the isotopic composition. Two 6-hour noble gas measurements, using mobile SAUNA sampling equipment were collected each day at different distances from the facility (1 - 100 km). The sampling locations were guided by atmospheric dispersion model results. Three samples from the stack itself were also collected. All 38 samples were shipped after collection to and measured with a SAUNA at the laboratory in Stockholm, Sweden. The environmental concentrations of 133Xe were measured and found to be in the range between 0.7 - 4 105 mBq/m3. Nine samples contained all four CTBT relevant radioxenon isotopes. The concentrations of the stack spike samples were in the range 2 109 - 4 1010 mBq/m3. This corresponds to a daily release of around 1 TBq. This is

  9. Monitoring of reported sudden emission rate changes of major radioxenon emitters in the northern and southern hemispheres in 2008 to assess their contribution to the respective radioxenon backgrounds

    NASA Astrophysics Data System (ADS)

    Saey, P. R. J.; Auer, M.; Becker, A.; Colmanet, S.; Hoffmann, E.; Nikkinen, M.; Schlosser, C.; Sonck, M.

    2009-04-01

    Atmospheric radioxenon monitoring is a key component of the verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Radiopharmaceutical production facilities (RPF) have recently been identified of emitting the major part of the environmental radioxenon measured at globally distributed monitoring sites deployed to strengthen the radionuclide part of the CTBT verification regime. Efforts to raise a global radioxenon emission inventory revealed that the global total emission from RPF's is 2-3 orders of magnitude higher than the respective emissions related to maintenance of all nuclear power plants (NPP). Given that situation we have seen in 2008 two peculiar hemisphere-specific situations: 1) In the northern hemisphere, a joint shutdown of the global largest four radiopharmaceutical facilities revealed the contribution of the normally 'masked' NPP related emissions. Due to an incident, the Molybdenum production at the "Institut des Radioéléments" (IRE) in Fleurus, Belgium, was shut down between Monday 25 August and 2 December 2008. IRE is the third largest global producer of medical isotopes. In the same period, but for different reasons, the other three worldwide largest producers (CRL in Canada, HFR in The Netherlands and NTP in South Africa) also had scheduled and unscheduled shutdowns. The activity concentrations of 133Xe measured at the Schauinsland Mountain station near Freiburg in Germany (situated 380 km SW of Fleurus) which have a mean of 4.8 mBq/m3 for the period February 2004 - August 2008, went down to 0.87 mBq/m3 for the period September - November 2008. 2) In the southern hemisphere, after a long break, the only radiopharmaceutical facility in Australia started up test production in late November 2008. In the period before the start-up, the background of radioxenon in Australia (Melbourne and Darwin) was below measurable quantities. During six test runs of the renewed RPF at ANSTO in Lucas Heights, up to 6 mBq/m3 of 133Xe were measured in

  10. Tracheal dead space influences regional ventilation measurement in dogs

    SciTech Connect

    Delaunois, L.; Boileau, R.; Martin, R.R. )

    1990-02-01

    The lung volume at which airway closure begins during expiration (closing volume, CV) can be measured (1) with a radioactive bolus inspired at residual volume (RV) and (2) with the single-breath N2 elimination test. In previous studies in dogs, we observed that N2 CV was systematically larger than 133Xe bolus CV (Xe CV) (N2 CV %vital capacity (VC) = 35 +/- 2.3 (SE) vs. Xe CV %VC = 24 +/- 2.2, P less than 0.01). Because the regional RV in the dog is evenly distributed throughout the lung and all airways closed at RV, N2 CV is related to the regional distribution of the tracheal N2; differences between N2 and Xe CV could then be related to the size of the inhaled dead space. Simultaneous measurements of Xe and N2 CV were performed at various sites of Xe bolus injection while the regional distribution of the bolus was measured. Injections at the level of the carina increased Xe CV to a value (30 +/- 1.4%VC) near simultaneous N2 CV (32 +/- 1.5%VC) and increased the unevenness of regional distribution of the Xe bolus. The difference between N2 and Xe CV is then the result of the size of the inspired tracheal dead space. Moreover, comparisons between different values of Xe CV require injections of the boluses at the same distance from the carina.

  11. Operations of the Automated Radioxenon Sampler/Analyzer - ARSA

    SciTech Connect

    Hayes, James C.; Abel, Keith H.; Bowyer, Ted W.; Heimbigner, Tom R.; Panisko, Mark E.; Reeder, Paul L.; McIntyre, Justin I.; Thompson, Robert C.; Todd, Lindsay C.; Warner, Ray A.

    1999-09-01

    The Automated Radioxenon Sampler/ Analyzer (ARSA), designed and built by Pacific Northwest National Laboratory (PNNL), for the Department of Energy, has exceeded measurement requirements for noble gas measurement systems established by the Comprehensive Nuclear-Test-Ban Treaty. Two units, one at PNNL and a second, sent to DME Corp. of Florida, were built and extensively tested. Both systems have successfully demonstrated stable xenon yields greater than 1.5 cm3 for an eight-hour collection period, corresponding to minimum detectable concentrations for 133Xe on the order of 0.1 mBq/m3 three times per day. High stable xenon yields are critical in obtaining these low minimum detectable concentrations. A history of testing and results that led to the high xenon yields of the ARSA system is presented. A compilation of field tests, laboratory tests and baseline tests that led to cost reduction, power savings and size reduction of the ARSA are also discussed. Lastly, the type of data generated from the ARSA of interest to data center personnel are discussed.

  12. The relation between spirometric measurements and arterial blood gas analysis in patients with chronic airflow obstruction

    PubMed Central

    Shibel, Elaine M.; Moser, Kenneth M.

    1970-01-01

    Spirometric studies and arterial blood gas analyses were statistically evaluated in 75 patients with chronic airways obstruction to determine whether any spirometric parameters can predict arterial blood gas status. Radioactive lung scans, both ventilation (using 133Xe gas) and perfusion (using 131I-MAA), were performed in selected patients. In all 75 patients as one group, no spirometric parameter correlated with resting arterial blood gases. Comparing spirometric values with arterial blood studies during exercise, 5% carbon dioxide breathing and 100% oxygen breathing revealed no consistently predictive correlation coefficients. Ventilation and perfusion lung scanning revealed that in patients whose ventilation/perfusion (V̇/Q) `match' was good, arterial blood gases approached normal, while hypoxaemia and/or hypercapnia were present when V̇/Q relationships were disturbed. Spirometry measures static and dynamic lung volumes, reflecting the mechanical and structural status of the lung-bellows system. Arterial blood gas status is conditioned by severe factors, including V̇/Q relationship, and can be determined accurately only by measurement in each individual patient. Images PMID:5489184

  13. Changes in the loco-regional cerebral blood flow (r.C.B.F.) during a simulation of weightlessness

    NASA Astrophysics Data System (ADS)

    Guell, A.; Dupui, Ph.; Barrere, M.; Fanjaud, G.; Bes, A.; Kotowskaia, A.

    Experiments of prolonged bedrest in antiorthostatic position are conducted in order to simulate cardio-circulatory modifications observed in weightlessness. Until now, no studies of r.C.B.F. have been effected in these conditions. Six young, healthy volunteers (average age 23.8) were placed in strict bedrest and in antiorthostatic position -4° for 7 days. The r.C.B.F. measurements were studied by 133Xe inhalation method using a 32 detectors system. Studies were made first in basal conditions, then between the 6th and 12th hr, and finally between the 72nd and the 78th hr after the beginning of the experiment. Three of the subjects received 0.450 mg of Clonidine daily during the experiment. In the subjects having taken no Clonidine, we observed a constant increase in r.C.B.F. (12, 17 and 16% respectively) in the first 12 hr; at the 72nd hour, all values had returned to basal state. This findings agrees with the well known notion of a rapid correction of hemodynamic disturbances observed in the first days of weightlessness. In the subjects treated with Clonidine, the increase of r.C.B.F. did not occur. Several mechanicsms of action are possible; the Clonidine affecting either the heart by inhibiting volemic atrial receptors, or the brain by direct vasoconstriction.

  14. Isotopic signature of atmospheric xenon released from light water reactors.

    PubMed

    Kalinowski, Martin B; Pistner, Christoph

    2006-01-01

    A global monitoring system for atmospheric xenon radioactivity is being established as part of the International Monitoring System to verify compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The isotopic activity ratios of (135)Xe, (133m)Xe, (133)Xe and (131m)Xe are of interest for distinguishing nuclear explosion sources from civilian releases. Simulations of light water reactor (LWR) fuel burn-up through three operational reactor power cycles are conducted to explore the possible xenon isotopic signature of nuclear reactor releases under different operational conditions. It is studied how ratio changes are related to various parameters including the neutron flux, uranium enrichment and fuel burn-up. Further, the impact of diffusion and mixing on the isotopic activity ratio variability are explored. The simulations are validated with reported reactor emissions. In addition, activity ratios are calculated for xenon isotopes released from nuclear explosions and these are compared to the reactor ratios in order to determine whether the discrimination of explosion releases from reactor effluents is possible based on isotopic activity ratios.

  15. The cerebrovascular CO2 reactivity during the acute phase of brain injury.

    PubMed

    Cold, G E; Jensen, F T; Malmros, R

    1977-01-01

    Using the intra-arterial 133xenon (133Xe) method, the cerebrovascular response to acute Paco2 reduction was studied in 26 unconscious, brain-injured patients subjected to controlled ventilation. The CO2 reactivity was calculated as delta in CBF/delta Paco2. The perfusion pressure was defined as the difference between mean arterial pressure and mean intraventricular pressure. Although the CO2 reactivities did not differ significantly from that in awake, normocapnic subjects, it was low in the acute phase of injury, especially in those patients with severe outcome in whom the brain-stem reflexes were often affected. An increase of the CO2 reactivity with time was observed, indicating normal response after 1-2 weeks. Chronic hypocapnia in six unconscious patients resulted in sustained CSF pH adaptation. The question whether a delay in CSF pH adapation exerts an influence on the CO2 reactivity, and the influence of cerebral lactacidosis on the CO2 response are discussed.

  16. Cerebral blood flow tomography with xenon-133

    SciTech Connect

    Lassen, N.A.

    1985-10-01

    Cerebral blood flow (CBF) can be measured tomographically by inhalation of Xenon-/sup 133/. The calculation is based on taking a sequence of tomograms during the wash-in and wash-out phase of the tracer. Due to the dynamic nature of the process, a highly sensitive and fast moving single photon emission computed tomograph (SPECT) is required. Two brain-dedicated SPECT systems designed for this purpose are mentioned, and the method is described with special reference to the limitations inherent in the soft energy of the 133Xe primary photons. CBF tomography can be used for a multitude of clinical and investigative purposes. This article discusses in particular its use for the selection of patients with carotid occlusion for extracranial/intracranial bypass surgery, for detection of severe arterial spasm after aneurysm bleeding, and for detection of low flow areas during severe migraine attacks. The use of other tracers for CBF tomography using SPECT is summarized with emphasis on the /sup 99m/Tc chelates that freely pass the intact blood-brain barrier. The highly sensitive brain-dedicated SPECT systems described are a prerequisite for achieving high resolution tomograms with such tracers.

  17. CTBTO Contractor Laboratory Test Sample Production Report

    SciTech Connect

    Bob Hague; Tracy Houghton; Nick Mann; Matt Watrous

    2013-08-01

    In October 2012 scientists from both Idaho National Laboratory (INL) and the CTBTO contact laboratory at Seibersdorf, Austria designed a system and capability test to determine if the INL could produce and deliver a short lived radio xenon standard in time for the standard to be measured at the CTBTO contact laboratory at Seibersdorf, Austria. The test included sample standard transportation duration and potential country entrance delays at customs. On October 23, 2012 scientists at the Idaho National Laboratory (INL) prepared and shipped a Seibersdorf contract laboratory supplied cylinder. The canister contained 1.0 scc of gas that consisted of 70% xenon and 30% nitrogen by volume. The t0 was October 24, 2012, 1200 ZULU. The xenon content was 0.70 +/ 0.01 scc at 0 degrees C. The 133mXe content was 4200 +/ 155 dpm per scc of stable xenon on t0 (1 sigma uncertainty). The 133Xe content was 19000 +/ 800 dpm per scc of stable xenon on t0 (1 sigma uncertainty).

  18. The upper limit of cerebral blood flow autoregulation in acute intracranial hypertension.

    PubMed

    Hauerberg, J; Xiaodong, M; Willumsen, L; Pedersen, D B; Juhler, M

    1998-04-01

    The present series of experiments was performed to investigate the influence of acute intracranial hypertension on the upper limit (UL) of cerebral blood flow (CBF) autoregulation. Three groups of eight rats each--one with normal intracranial pressure (ICP) (2 mmHg), one with ICP = 30 mmHg, and one with ICP = 50 mmHg--were investigated. Intracranial hypertension was maintained by continuous infusion of lactated Ringer's solution into the cisterna magna, where the pressure was used as ICP. Cerebral perfusion pressure (CPP), calculated as mean arterial blood pressure (MABP)-ICP, was increased stepwise by continuous intravenous infusion of norepinephrine. CBF was calculated by the intracarotid 133Xe method. In all three groups the corresponding CBF/CPP curve included a plateau where CBF was independent of changes in CPP, showing intact autoregulation. At normal ICP the UL was found at a CPP of 141 +/-2 mmHg, at ICP = 30 mmHg the UL was 103+/-5 mmHg, and at ICP = 50 mmHg the UL was found at 88+/-7 mmHg. This shift of the UL was more pronounced than the shift of the lower limit (LL) of the CBF autoregulation found previously. We conclude that intracranial hypertension is followed by both a shift toward lower CPP values and a narrowing of the autoregulated interval between the LL and the UL.

  19. Analysis of data from sensitive U.S. monitoring stations for the Fukushima Dai-ichi nuclear reactor accident.

    PubMed

    Biegalski, S R; Bowyer, T W; Eslinger, P W; Friese, J A; Greenwood, L R; Haas, D A; Hayes, J C; Hoffman, I; Keillor, M; Miley, H S; Moring, M

    2012-12-01

    The March 11, 2011 9.0 magnitude undersea megathrust earthquake off the coast of Japan and subsequent tsunami waves triggered a major nuclear event at the Fukushima Dai-ichi nuclear power station. At the time of the event, units 1, 2, and 3 were operating and units 4, 5, and 6 were in a shutdown condition for maintenance. Loss of cooling capacity to the plants along with structural damage caused by the earthquake and tsunami resulted in a breach of the nuclear fuel integrity and release of radioactive fission products to the environment. Fission products started to arrive in the United States via atmospheric transport on March 15, 2011 and peaked by March 23, 2011. Atmospheric activity concentrations of (131)I reached levels of 3.0×10(-2) Bqm(-3) in Melbourne, FL. The noble gas (133)Xe reached atmospheric activity concentrations in Ashland, KS of 17 Bqm(-3). While these levels are not health concerns, they were well above the detection capability of the radionuclide monitoring systems within the International Monitoring System of the Comprehensive Nuclear-Test-Ban Treaty.

  20. Evaluation of radioxenon releases in Australia using atmospheric dispersion modelling tools.

    PubMed

    Tinker, Rick; Orr, Blake; Grzechnik, Marcus; Hoffmann, Emmy; Saey, Paul; Solomon, Stephen

    2010-05-01

    The origin of a series of atmospheric radioxenon events detected at the Comprehensive Test Ban Treaty Organisation (CTBTO) International Monitoring System site in Melbourne, Australia, between November 2008 and February 2009 was investigated. Backward tracking analyses indicated that the events were consistent with releases associated with hot commission testing of the Australian Nuclear Science Technology Organisation (ANSTO) radiopharmaceutical production facility in Sydney, Australia. Forward dispersion analyses were used to estimate release magnitudes and transport times. The estimated (133)Xe release magnitude of the largest event (between 0.2 and 34 TBq over a 2 d window), was in close agreement with the stack emission releases estimated by the facility for this time period (between 0.5 and 2 TBq). Modelling of irradiation conditions and theoretical radioxenon emission rates were undertaken and provided further evidence that the Melbourne detections originated from this radiopharmaceutical production facility. These findings do not have public health implications. This is the first comprehensive study of atmospheric radioxenon measurements and releases in Australia.

  1. Sufentanil does not increase cerebral blood flow in healthy human volunteers

    SciTech Connect

    Mayer, N.; Weinstabl, C.; Podreka, I.; Spiss, C.K. )

    1990-08-01

    The effect of sufentanil on human cerebral blood flow (CBF) was studied in seven unpremedicated, healthy volunteers 31 +/- 3.5 yr of age (mean +/- SD) and either sex. CBF (ml.100 g-1.min-1) was measured noninvasively with the 133Xe clearance technique and a scintillation camera before and after sufentanil 0.5 micrograms/kg administered intravenously. This technique provides values for global blood flow and for gray and white matter blood flow, and from 13 preselected regions in one hemisphere. After the administration of sufentanil, the volunteers were stimulated verbally in order to prevent their loss of consciousness and hypercarbia. Heart rate (HR), arterial pressure, oxyhemoglobin saturation, and end-tidal CO2 ETCO2 were recorded during the measurements. Neither global CBF (46.1 +/- 1.6 control and 43 +/- 1.9 after sufentanil, mean +/- SEM) nor gray (76.5 +/- 3.2 and 70.9 +/- 6.1) or white (22.7 +/- 1.5 and 24.2 +/- 1.6) matter blood flow changed significantly after sufentanil administration. As well, no significant differences in HR (72 +/- 4 control and 79 +/- 4 beats per min after sufentanil) and ETCO2 (39.8 +/- 1.4 and 41.1 +/- 1.1 mmHg) were observed. It is concluded that sufentanil has no significant effect on CBF in healthy human volunteers.

  2. Measuring radioactive noble gases by absorption in polycarbonates and other organics: From radon indoors to nuclear safety

    NASA Astrophysics Data System (ADS)

    Pressyanov, Dobromir S.

    2013-07-01

    The report summarizes recent research and practice of using materials with high absorption ability to noble gases to measure their radioactive isotopes. Most of the studies employ bisphenol-A based polycarbonates, because of their remarkably high absorption ability to noble gases. This is the material of which commercial CDs/DVDs are made and they may serve as serendipitous, already available in dwellings, radon and thoron detectors. We present the essence of the gathered experimental evidence that the CD/DVD method can successfully address some long-lasted problems in radon dosimetry: The first is making sufficiently precise retrospective 222Rn dosimetry for the purposes of epidemiological studies and risk estimation. The second is rapid identification of buildings with radon problem. We demonstrate how this can be used to develop an integrated approach to the radon problem. Within this approach detection, diagnostic and mitigation are considered as an unified whole, and the interval between the decision to provide disks for analysis and the complete mitigation of the building, if radon problem is identified, is short. Besides radon and thoron, bisphenol-A based polycarbonates were successfully used to measure 85Kr and 133Xe for the purposes of the effluents control and nuclear safety of nuclear installations. The perspectives to employ other organic materials in which noble gases are highly soluble for measurement of their radioactive isotopes are also discussed.

  3. Effects of local alpha2-adrenergic receptor blockade on adipose tissue lipolysis during prolonged systemic adrenaline infusion in normal man.

    PubMed

    Simonsen, Lene; Enevoldsen, Lotte H; Stallknecht, Bente; Bülow, Jens

    2008-03-01

    During prolonged adrenaline infusion, lipolysis peaks within 30 min and thereafter tends to decline, and we hypothesized that the stimulation of local adipose tissue alpha2-adrenergic receptors accounts for this decline. The lipolytic effect of a prolonged intravenous adrenaline infusion combined with local infusion of the alpha2-blocker phentolamine in superficial and deep abdominal subcutaneous adipose tissue and in preperitoneal adipose tissue was studied in seven healthy subjects. The interstitial glycerol concentration in the three adipose tissue depots was measured by the microdialysis method. Regional adipose tissue blood flow was measured by the (133)Xe clearance technique. Regional glycerol output (lipolytic rate) was calculated from these measurements and simultaneous measurements of arterial glycerol concentrations. Adrenaline infusion increased lipolysis in all three depots (data previously published). Phentolamine infusion did not augment lipolysis in the subcutaneous depots while it increased the lipolytic rate in the preperitoneal depot. It is concluded that alpha2-adrenergic receptors do not have a significant effect on subcutaneous adipose tissue lipolysis during high circulating adrenaline concentrations, and the decrease in lipolysis in subcutaneous adipose tissue under prolonged adrenaline stimulation is thus not attributed to alpha2-adrenergic receptor inhibition of lipolysis. However, in the preperitoneal adipose tissue depot, alpha2-adrenergic receptor tone plays a role for the lipolytic rate obtained during prolonged adrenaline stimulation.

  4. Clinical experience with technetium-99m DTPA aerosol with perfusion scintigraphy in suspected pulmonary embolism

    SciTech Connect

    Selby, J.B.; Gardner, J.J.

    1987-01-01

    To evaluate the clinical value of radioaerosol imaging, 156 patients with suspected pulmonary embolism (PE) were studied. In 25 patients, a preperfusion xenon-133 (Xe-133) study was compared with a postperfusion study using Tc-99m DTPA aerosol. It was found that they were of equal value most of the time (56%), but that the aerosol study was more often helpful. Because of this, and the technical ease of using six standard views with radioaerosol, the series was completed using perfusion scintigraphy followed by radioaerosol images. In 19 patients the perfusion scintigraphy with Tc-99 macroaggregated albumin (Tc-99m MAA) was normal or nearly normal and no aerosol study was required. Tc-99m DTPA aerosol images were satisfactory when the count rate was at least twice and preferably three times that of the previous perfusion study. There were 17 studies (11%) classified as intermediate. There were 26 patients classified as high probability for PE, and angiographic or autopsy correlation was available in 14. All of the 14 proved to have PE. In the 113 patients classified as low probability, there were ten with angiographic or autopsy correlation. In the ten, there was one patient with a small pulmonary embolus found at autopsy. Clinical follow-up for over two months confirmed the absence of PE in the remainder of this group. Aerosol studies have proven technically easier to perform and a satisfactory substitute for xenon imaging in suspected PE.

  5. Scintigraphic detection of pulmonary embolism in patients with obstructive pulmonary disease

    SciTech Connect

    Alderson, P.O.; Biello, D.R.; Sachariah, K.G.; Siegel, B.A.

    1981-03-01

    The 133Xe ventilation studies, 99mTc perfusion lung images, and pulmonary angiograms of 83 patients with obstructive pulmonary disease and suspected pulmonary emboli were reviewed. Each patient had ventilation abnormalities suggesting OPD and at least one region showing matched V-P abnormalities. All angiograms were obtained within 72 hours of the V-P study and were reviewed independently. The overall sensitivity of V-P imaging for PE in this population was 0.83 and its specificity was 0.92. False-negative interpretations occurred in three of the 16 patients who showed ventilation abnormalities in more than 50% of their lung fields. In the 67 patients with ventilation abnormalities in less than or equal to 50% of their lung fields the sensitivity and specificity for detecting PE were high, V-P imaging is a reliable method for detecting PE in patients with regions of V-P match, if the ventilation abnormalities are limited in extent.

  6. Ultrasound modulated light blood flow measurement using intensity autocorrelation function: a Monte-Carlo simulation

    NASA Astrophysics Data System (ADS)

    Tsalach, A.; Metzger, Y.; Breskin, I.; Zeitak, R.; Shechter, R.

    2014-03-01

    Development of techniques for continuous measurement of regional blood flow, and in particular cerebral blood flow (CBF), is essential for monitoring critical care patients. Recently, a novel technique, based on ultrasound modulation of light was developed for non-invasive, continuous CBF monitoring (termed ultrasound-tagged light (UTL or UT-NIRS)), and shown to correlate with readings of 133 Xe SPECT1 and laser Doppler2. Coherent light is introduced into the tissue concurrently with an Ultrasound (US) field. Displacement of scattering centers within the sampled volume induced by Brownian motion, blood flow and the US field affects the photons' temporal correlation. Hence, the temporal fluctuations of the obtained speckle pattern provide dynamic information about the blood flow. We developed a comprehensive simulation, combining the effects of Brownian motion, US and flow on the obtained speckle pattern. Photons trajectories within the tissue are generated using a Monte-Carlo based model. Then, the temporal changes in the optical path due to displacement of scattering centers are determined, and the corresponding interference pattern over time is derived. Finally, the light intensity autocorrelation function of a single speckle is calculated, from which the tissue decorrelation time is determined. The simulation's results are compared with in-vitro experiments, using a digital correlator, demonstrating decorrelation time prediction within the 95% confidence interval. This model may assist in the development of optical based methods for blood flow measurements and particularly, in methods using the acousto-optic effect.

  7. SPECT determination of regional cerebral blood flow in hypertensive patients before and after clonidine

    SciTech Connect

    Devous, M.D.; Reed, W.G.; Chehabi, H.H.; Bonte, F.J.

    1985-05-01

    Regional cerebral blood flow (rCBF) was determined by SPECT of 133-Xe inert gas washout in 18 hypertensive patients (PTS) upon admission and after treatment with oral clonidine (CL, 0.2 mg, then 0.1 mg/hr until diastolic pressure reached 105 mm Hg or fell by 30 mm Hg). CL reduced mean arterial pressure (MAP) from 160 (200/140) to 133 (150/100) mm Hg over 4-6 hr. RCBF was quantitated in 14 gray matter regions from cross-sectional images and analyzed for differences from normal controls and changes with CL. Initial rCBF was lower in HI PTS than in either normal controls of LO PTS in all brain regions. CL lowered MAP in HI PTS by 52 +- 15 mm Hg and caused reduction in all gray matter regions except right frontal and right temporal (mean reduction 5 +- 2 ml/min/100 g, rho<.05). RCBF images were also evaluated by two trained observers for initial regional defects and for changes with CL. LO PTS were more likely to have defects in rCBF images at rest which would resolve with CL. HI PTS frequently had normal images at rest and developed defects with CL. In summary, the study suggests that SPECT may be useful in detecting rCBF abnormalities in hypertensive PTS at rest and following reductions in MAP.

  8. Radioxenon detections in the CTBT international monitoring system likely related to the announced nuclear test in North Korea on February 12, 2013.

    PubMed

    Ringbom, A; Axelsson, A; Aldener, M; Auer, M; Bowyer, T W; Fritioff, T; Hoffman, I; Khrustalev, K; Nikkinen, M; Popov, V; Popov, Y; Ungar, K; Wotawa, G

    2014-02-01

    Observations made in April 2013 of the radioxenon isotopes (133)Xe and (131m)Xe at measurement stations in Japan and Russia, belonging to the International Monitoring System for verification of the Comprehensive Nuclear-Test-Ban Treaty, are unique with respect to the measurement history of these stations. Comparison of measured data with calculated isotopic ratios as well as analysis using atmospheric transport modeling indicate that it is likely that the xenon measured was created in the underground nuclear test conducted by North Korea on February 12, 2013, and released 7-8 weeks later. More than one release is required to explain all observations. The (131m)Xe source terms for each release were calculated to 0.7 TBq, corresponding to about 1-10% of the total xenon inventory for a 10 kt explosion, depending on fractionation and release scenario. The observed ratios could not be used to obtain any information regarding the fissile material that was used in the test.

  9. Uncertainty quantification for discrimination of nuclear events as violations of the comprehensive nuclear-test-ban treaty.

    PubMed

    Sloan, Jamison; Sun, Yunwei; Carrigan, Charles

    2016-05-01

    Enforcement of the Comprehensive Nuclear Test Ban Treaty (CTBT) will involve monitoring for radiologic indicators of underground nuclear explosions (UNEs). A UNE produces a variety of radioisotopes which then decay through connected radionuclide chains. A particular species of interest is xenon, namely the four isotopes (131m)Xe, (133m)Xe, (133)Xe, and (135)Xe. Due to their half lives, some of these isotopes can exist in the subsurface for more than 100 days. This convenient timescale, combined with modern detection capabilities, makes the xenon family a desirable candidate for UNE detection. Ratios of these isotopes as a function of time have been studied in the past for distinguishing nuclear explosions from civilian nuclear applications. However, the initial yields from UNEs have been treated as fixed values. In reality, these independent yields are uncertain to a large degree. This study quantifies the uncertainty in xenon ratios as a result of these uncertain initial conditions to better bound the values that xenon ratios can assume. We have successfully used a combination of analytical and sampling based statistical methods to reliably bound xenon isotopic ratios. We have also conducted a sensitivity analysis and found that xenon isotopic ratios are primarily sensitive to only a few of many uncertain initial conditions.

  10. Maximum reasonable radioxenon releases from medical isotope production facilities and their effect on monitoring nuclear explosions.

    PubMed

    Bowyer, Theodore W; Kephart, Rosara; Eslinger, Paul W; Friese, Judah I; Miley, Harry S; Saey, Paul R J

    2013-01-01

    Fission gases such as (133)Xe are used extensively for monitoring the world for signs of nuclear testing in systems such as the International Monitoring System (IMS). These gases are also produced by nuclear reactors and by fission production of (99)Mo for medical use. Recently, medical isotope production facilities have been identified as the major contributor to the background of radioactive xenon isotopes (radioxenon) in the atmosphere (Stocki et al., 2005; Saey, 2009). These releases pose a potential future problem for monitoring nuclear explosions if not addressed. As a starting point, a maximum acceptable daily xenon emission rate was calculated, that is both scientifically defendable as not adversely affecting the IMS, but also consistent with what is possible to achieve in an operational environment. This study concludes that an emission of 5 × 10(9) Bq/day from a medical isotope production facility would be both an acceptable upper limit from the perspective of minimal impact to monitoring stations, but also appears to be an achievable limit for large isotope producers.

  11. Radioxenon spiked air

    DOE PAGES

    Watrous, Matthew G.; Delmore, James E.; Hague, Robert K.; ...

    2015-08-27

    Four of the radioactive xenon isotopes (131mXe, 133mXe, 133Xe and 135Xe) with half-lives ranging from 9 h to 12 days are produced from nuclear fission and can be detected from days to weeks following their production and release. Being inert gases, they are readily transported through the atmosphere. Sources for release of radioactive xenon isotopes include operating nuclear reactors via leaks in fuel rods, medical isotope production facilities, and nuclear weapons' detonations. They are not normally released from fuel reprocessing due to the short half-lives. The Comprehensive Nuclear-Test-Ban Treaty has led to creation of the International Monitoring System. The Internationalmore » Monitoring System, when fully implemented, will consist of one component with 40 stations monitoring radioactive xenon around the globe. Monitoring these radioactive xenon isotopes is important to the Comprehensive Nuclear-Test-Ban Treaty in determining whether a seismically detected event is or is not a nuclear detonation. A variety of radioactive xenon quality control check standards, quantitatively spiked into various gas matrices, could be used to demonstrate that these stations are operating on the same basis in order to bolster defensibility of data across the International Monitoring System. This study focuses on Idaho National Laboratory's capability to produce three of the xenon isotopes in pure form and the use of the four xenon isotopes in various combinations to produce radioactive xenon spiked air samples that could be subsequently distributed to participating facilities.« less

  12. Modelling the global atmospheric transport and deposition of radionuclides from the Fukushima Dai-ichi nuclear accident

    NASA Astrophysics Data System (ADS)

    Christoudias, T.; Lelieveld, J.

    2013-02-01

    We modeled the global atmospheric dispersion and deposition of radionuclides released from the Fukushima Dai-ichi nuclear power plant accident. The EMAC atmospheric chemistry - general circulation model was used, with circulation dynamics nudged towards ERA-Interim reanalysis data. We applied a resolution of approximately 0.5 degrees in latitude and longitude (T255). The model accounts for emissions and transport of the radioactive isotopes 131I and 137Cs, and removal processes through precipitation, particle sedimentation and dry deposition. In addition, we simulated the release of 133Xe, a noble gas that can be regarded as a passive transport tracer of contaminated air. The source terms are based on Chino et al. (2011) and Stohl et al. (2012); especially the emission estimates of 131I are associated with a high degree of uncertainty. The calculated concentrations have been compared to station observations by the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO). We calculated that about 80% of the radioactivity from Fukushima which was released to the atmosphere deposited into the Pacific Ocean. In Japan a large inhabited land area was contaminated by more than 40 kBq m-2. We also estimated the inhalation and 50-year dose by 137Cs, 134Cs and 131I to which the people in Japan are exposed.

  13. Modelling the global atmospheric transport and deposition of radionuclides from the Fukushima Dai-ichi nuclear accident

    NASA Astrophysics Data System (ADS)

    Christoudias, T.; Lelieveld, J.

    2012-09-01

    We modeled the global atmospheric dispersion and deposition of radionuclides released from the Fukushima Dai-ichi nuclear power plant accident. The EMAC atmospheric chemistry - general circulation model was used, with circulation dynamics nudged towards ERA-Interim reanalysis data. We applied a resolution of approximately 0.5 degrees in latitude and longitude (T255). The model accounts for emissions and transport of the radioactive isotopes 131I and 137Cs, and removal processes through precipitation, particle sedimentation and dry deposition. In addition, we simulated the release of 133Xe, a noble gas that can be regarded as a passive transport tracer of contaminated air. The source terms are based on Stohl et al. (2012) and Chino et al. (2011); especially the emission estimates of 131I are associated with a high degree of uncertainty. The calculated concentrations have been compared to station observations by the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO). We calculated that about 80% of the radioactivity from Fukushima which was released to the atmosphere deposited into the Pacific Ocean. In Japan a land area of 34 000 km2 around the reactors, inhabited by nearly 10 million people, was contaminated by more than 40 kBq m-2. We also estimated the inhalation and 50-yr dose by 137Cs and 131I to which the people in Japan have been exposed.

  14. Improved β-γ Coincidence Detector For Radioxenon Detection

    SciTech Connect

    Cooper, Matthew W; Carman, April J; Hayes, James C; Heimbigner, Tom R; Hubbard, Charles W; Litke, Kevin E; McIntyre, Justin I; Morris, Scott J; Ripplinger, Michael D; Suarez, Reynold

    2005-08-31

    The Automated Radio-xenon Analyzer/Sampler (ARSA), built by Pacific Northwest National Laboratory (PNNL), can collect and detect several radioxenon isotopes. ARSA is very sensitive to 133Xe, 131mXe, 133mXe and 135Xe due to the compact high efficiency coincidence detector it uses. For this reason it is an excellent treaty monitoring and environmental sampling device. Although the system is shown to be both robust and reliable, based on several field tests, it is also complex due to a detailed photomultiplier tube gain matching regime. This complexity is a problem from a maintenance and quality assurance/quality control (QA/QC) standpoint. To reduce these issues a simplified coincident detector has been developed. A comparison of three different well detectors has been completed. In addition, a new plastic scintillator gas cell was constructed. The new simplified detector system has been demonstrated to equal or better performance compared with the original ARSA design in spectral resolution and efficiency and significantly easier to setup and calibrate.

  15. Postoperative luxury perfusion syndrome in patients with severe subarachnoid hemorrhage treated by early aneurysmal clipping.

    PubMed

    Ohta, H

    1990-01-01

    Cerebral blood flow (CBF) was measured in 90 patients who underwent early aneurysmal clipping after subarachnoid hemorrhage (SAH). Measurements were made by a noninvasive, two-dimensional method involving intravenous injection of 133Xe. Patients of Hunt and Hess grades I and II exhibited normal to slightly subnormal CBF, without significant changes, during the study period. Grades III-V patients had almost normal CBF in the early postoperative period, but their CBF gradually decreased, becoming significantly low after day 31. It is noteworthy that in grades IV and V patients, CBF was abnormally high in the acute stage, relative to their poor neurological condition; these patients were considered to have the "global luxury perfusion syndrome." The syndrome was not uncommon in patients with severe SAH. Possible causative or contributory factors are attempts to surgically reduce intracranial pressure, which leads to increased cerebral perfusion pressure, and concomitant global dysautoregulation. In patients with this syndrome, maneuvers intended to increase CBF should be avoided, as they may aggravate brain swelling or cause hemorrhagic events. Positron emission tomographic studies will provide more accurate and useful information concerning the management of SAH patients.

  16. Closure Report for Corrective Action Unit 107: Low Impact Soil Sites, Nevada Test Site, Nevada with ROTC-1

    SciTech Connect

    Matthews, Patrick

    2009-06-09

    CAU 107, “Low Impact Soil Sites,” consists of 15 CASs in Areas 1, 2, 3, 4, 5, 9, 10, and 18 of the NTS. The closure alternatives included No Further Action and Closure in Place with Administrative Controls. This CR provides a summary of completed closure activities. ROTC Justification: The FFACO UR as published in the Closure Report for Corrective Action Unit 107: Low Impact Soil Sites, Nevada Test Site, Nevada (NNSA/NSO, 2009) states that the UR for CAS 18-23-02, U-18d Crater (Sulky), was implemented for assumed radioactive contamination that could cause a dose greater that 25 millirems per year. This document further clarifies that this was based on particulate releases of radionuclides identified in Radiological Effluents Released from U.S. Continental Tests, 1961 through 1992 (DOE/NV, 1996). The radionuclides listed in this document are krypton (Kr)-85, Kr-85m, Kr-87, Kr-88, rubidium (Rb)-87, strontium (Sr)-89, Sr-91, yttrium (Y)-91, iodine (I)-131, I-132, I-133, I-134, I-135, xeon (Xe)-133, Xe-135, Xe-138, cesium (Cs)-135, Cs-138, barium (Ba)-139, and Ba-140.

  17. Automatic radioxenon analyzer for CTBT monitoring

    SciTech Connect

    Bowyer, T.W.; Abel, K.H.; Hensley, W.K.

    1996-12-01

    Over the past 3 years, with support from US DOE`s NN-20 Comprehensive Test Ban Treaty (CTBT) R&D program, PNNL has developed and demonstrated a fully automatic analyzer for collecting and measuring the four Xe radionuclides, {sup 131m}Xe(11.9 d), {sup 133m}Xe(2.19 d), {sup 133}Xe (5.24 d), and {sup 135}Xe(9.10 h), in the atmosphere. These radionuclides are important signatures in monitoring for compliance to a CTBT. Activity ratios permit discriminating radioxenon from nuclear detonation and that from nuclear reactor operations, nuclear fuel reprocessing, or medical isotope production and usage. In the analyzer, Xe is continuously and automatically separated from the atmosphere at flow rates of about 7 m{sup 3}/h on sorption bed. Aliquots collected for 6-12 h are automatically analyzed by electron-photon coincidence spectrometry to produce sensitivities in the range of 20-100 {mu}Bq/m{sup 3} of air, about 100-fold better than with reported laboratory-based procedures for short time collection intervals. Spectral data are automatically analyzed and the calculated radioxenon concentrations and raw gamma- ray spectra automatically transmitted to data centers.

  18. Underground Sources of Radioactive Noble Gas

    SciTech Connect

    Hayes, James C.; Bowyer, Ted W.; Cordova, Elsa A.; Kirkham, Randy R.; Misner, Alex C.; Olsen, Khris B.; Woods, Vincent T.; Emer, Dudley

    2013-05-01

    It is well known that radon is present in relatively high concentrations below the surface of the Earth due to natural decay of uranium and thorium. However, less information is available on the background levels of other isotopes such as 133Xe and 131mXe produced via spontaneous fission of either manmade or naturally occurring elements. The background concentrations of radioxenon in the subsurface are important to understand because these isotopes potentially can be used to confirm violations of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) during an On-Site Inspection (OSI). Recently, Pacific Northwest National Laboratory (PNNL) measured radioxenon concentrations from the subsurface at the Nevada Nuclear Security Site (NNSS—formerly known as the Nevada Test Site) to determine whether xenon isotope background levels could be detected from spontaneous fission of naturally occurring uranium or legacy 240Pu as a result of historic nuclear testing. In this paper, we discuss the results of those measurements and review the sources of xenon background that must be taken into account during OSI noble gas measurements.

  19. Effect of nephrectomy and captopril on autoregulation of cerebral blood flow in rats.

    PubMed

    Pedersen, Trine Fischer; Paulson, Olaf B; Nielsen, Arne Høj; Strandgaard, Svend

    2003-09-01

    The present study investigated the effect of circulating versus locally present renin on cerebral blood flow (CBF) and its autoregulation in rats. CBF was measured repetitively with the intracarotid 133Xe injection method, whereas blood pressure was lowered to determine the lower limit of autoregulation. To remove renin from the blood, rats were bilaterally nephrectomized and kept alive with peritoneal dialysis for 48 h. Five groups of animals were studied: 1) nephrectomized dialyzed rats, 2) nephrectomized dialyzed rats given a single intravenous dose of the angiotensin-converting enzyme inhibitor captopril (10 mg/kg), 3) sham nephrectomized and dialyzed rats, 4) rats receiving drugs as dialyzed rats but no surgery, and 5) rats given the same diet as the other groups but no drugs and no surgery. Baseline blood pressure was significantly lower in nephrectomized rats compared with controls. Nephrectomy, captopril, sham operation, or dialysis did not influence baseline CBF. The lower limit of CBF autoregulation was significantly lower in nephrectomized (53 +/- 4 mmHg) and sham-operated (58 +/- 4 mmHg) rats compared with diet control rats (78 +/- 3 mmHg). Captopril significantly decreased the lower limit in nephrectomized rats (35 +/- 2 mmHg). Thus removal of circulating renin caused no change in the lower limit of autoregulation. By contrast, captopril lowered the lower limit even in the absence of circulating renin and hence appeared to exert its effect on components of the renin-angiotensin system in the cerebral resistance vessel walls.

  20. The effect of amphetamine on regional cerebral blood flow during cognitive activation in schizophrenia

    SciTech Connect

    Daniel, D.G.; Weinberger, D.R.; Jones, D.W.; Zigun, J.R.; Coppola, R.; Handel, S.; Bigelow, L.B.; Goldberg, T.E.; Berman, K.F.; Kleinman, J.E. )

    1991-07-01

    To explore the role of monoamines on cerebral function during specific prefrontal cognitive activation, we conducted a double-blind placebo-controlled crossover study of the effects of 0.25 mg/kg oral dextroamphetamine on regional cerebral blood flow (rCBF) as determined by 133Xe dynamic single-photon emission-computed tomography (SPECT) during performance of the Wisconsin Card Sorting Test (WCST) and a sensorimotor control task. Ten patients with chronic schizophrenia who had been stabilized for at least 6 weeks on 0.4 mg/kg haloperidol participated. Amphetamine produced a modest, nonsignificant, task-independent, global reduction in rCBF. However, the effect of amphetamine on task-dependent activation of rCBF (i.e., WCST minus control task) was striking. Whereas on placebo no significant activation of rCBF was seen during the WCST compared with the control task, on amphetamine significant activation of the left dorsolateral prefrontal cortex (DLPFC) occurred (p = 0.0006). Both the mean number of correct responses and the mean conceptual level increased (p less than 0.05) with amphetamine relative to placebo. In addition, with amphetamine, but not with placebo, a significant correlation (p = -0.71; p less than 0.05) emerged between activation of DLPFC rCBF and performance of the WCST task. These findings are consistent with animal models in which mesocortical catecholaminergic activity modulates and enhances the signal-to-noise ratio of evoked cortical activity.

  1. [Shielding ability of lead loaded radiation resistant gloves].

    PubMed

    Kawano, T; Ebihara, H

    1990-02-01

    The shielding ability of radiation resistant gloves was examined. The gloves are made of lead loaded (as PbO2) polyvinyl chloride resin and are about 0.4 mm in thickness (70 mg/cm2). Eleven test pieces were sampled from each of three gloves (total 33) and the transmission rates for radiations (X-ray or gamma-ray) through the test pieces were measured with radiation sources, 99mTc, 57Co, 133Ba, 133Xe and 241Am. The differences of the transmission rates for radiations by the positions of the gloves were smaller than 15%, and the differences by three gloves were smaller than 5% in the case of 60 keV and 141 keV radiations. The average transmission rates for radiations in the 33 test pieces were about 40% for 30 keV radiation, about 90% for 80 keV and 140 keV radiations. The shielding characteristic of the gloves is equivalent to about 0.026 mm thick lead plate.

  2. Tritium discrimination using cluster size information from a DGEM detector

    NASA Astrophysics Data System (ADS)

    Surette, R. A.; Dubeau, J.

    2005-02-01

    Measurement of tritium-in-air concentrations is complicated by the presence of gamma radiation, 14C, and noble gas radionuclides. In most cases the signal from tritium, in conventional ion chamber-based monitors, is much smaller than that from equal concentrations of interfering radioactive gases. The lack of discrimination between tritium and other radioactive interferences frequently results in an overestimation of the tritium hazard. This report describes a method to effectively discriminate between tritium and other interfering airborne radioactive gases using ionization cluster size information from a double gas electron multiplier (DGEM) and a suitable readout array. The readout array consists of 121 pads (an 11×11 matrix of 4×4 mm pads on 6 mm centres) on a printed circuit board, each connected to a charge sensitive amplifier. The prototype-automated discriminating monitor typically indicated a spillover fraction, in the tritium channel, in the order of ±5% for binary mixtures of tritium and 14C, 85Kr, 133Xe or 41Ar. A custom-made dynamic cluster-fitting algorithm gives results in real-time with very good accuracy under extreme conditions.

  3. Advanced Imaging Modalities in the Detection of Cerebral Vasospasm

    PubMed Central

    Mills, Jena N.; Mehta, Vivek; Russin, Jonathan; Amar, Arun P.; Rajamohan, Anandh; Mack, William J.

    2013-01-01

    The pathophysiology of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) is complex and is not entirely understood. Mechanistic insights have been gained through advances in the capabilities of diagnostic imaging. Core techniques have focused on the assessment of vessel caliber, tissue metabolism, and/or regional perfusion parameters. Advances in imaging have provided clinicians with a multifaceted approach to assist in the detection of cerebral vasospasm and the diagnosis of delayed ischemic neurologic deficits (DIND). However, a single test or algorithm with broad efficacy remains elusive. This paper examines both anatomical and physiological imaging modalities applicable to post-SAH vasospasm and offers a historical background. We consider cerebral blood flow velocities measured by Transcranial Doppler Ultrasonography (TCD). Structural imaging techniques, including catheter-based Digital Subtraction Angiography (DSA), CT Angiography (CTA), and MR Angiography (MRA), are reviewed. We examine physiologic assessment by PET, HMPAO SPECT, 133Xe Clearance, Xenon-Enhanced CT (Xe/CT), Perfusion CT (PCT), and Diffusion-Weighted/MR Perfusion Imaging. Comparative advantages and limitations are discussed. PMID:23476766

  4. Analysis of data from sensitive U.S. monitoring stations for the Fukushima Dai-ichi nuclear reactor accident

    SciTech Connect

    Biegalski, Steven R.; Bowyer, Ted W.; Eslinger, Paul W.; Friese, Judah I.; Greenwood, Lawrence R.; Haas, Derek A.; Hayes, James C.; Hoffman, Ian; Keillor, Martin E.; Miley, Harry S.; Morin, Marc P.

    2012-12-01

    The March 11, 2011 9.0 magnitude undersea megathrust earthquake off the coast of Japan and subsequent tsunami waves triggered a major nuclear event at the Fukushima Dai-ichi nuclear power station. At the time of the event, units 1, 2, and 3 were operating and units 4, 5, and 6 were in a shutdown condition for maintenance. Loss of cooling capacity to the plants along with structural damage caused by the earthquake and tsunami resulted in a breach of the nuclear fuel integrity and release of radioactive fission products to the environment. Fission products started to arrive in the United States via atmospheric transport on March 15, 2011 and peaked by March 23, 2011. Atmospheric activity concentrations of 131I reached levels of 3.0 * 10*2 Bqm*3 in Melbourne, FL. The noble gas 133Xe reached atmospheric activity concentrations in Ashland, KS of 17 Bqm*3. While these levels are not health concerns, they were well above the detection capability of the radionuclide monitoring systems within the International Monitoring System of the Comprehensive Nuclear-Test-Ban Treaty.

  5. Patterns of pulmonary perfusion scans in normal subjects

    SciTech Connect

    Wallace, J.M.; Moser, K.M.; Hartman, M.T.; Ashburn, W.L.

    1981-01-01

    A vital factor conditioning the usage of the pulmonary perfusion (Q) scan in the evaluation of patients suspected of pulmonary embolism is the prevalence of abnormal Q scans in subjects free of cardiopulmonary disease. Because this prevalence has not been well defined, we performed Q scans in 80 nonsmoking subjects 18 to 29 yr of age having no known active cardiopulmonary disease. Each subject underwent a history, physical examination, electrocardiogram, spirometry, and PA chest roentgenogram, followed by a 6-view Q scan. Two subjects in whom a Q defect was suspected underwent a /sup 133/Xe equilibrium-washout ventilation (V) scan. All Q scans were interpreted blindly and independently by 2 experienced readers. Seventy-nine of the 80 Q scans were read as normal. No subject demonstrated a lobar or segmental defect. One of the 80 subjects, who had a mild pectus excavatum, had a left upper lobe subsegmental defect, which was not seen on the V scan. Based on the statistical analysis of these data, no more than 3.68% of normal nonsmoking persons in this age group may have a lobar or segmental Q scan defect and no more than 6.77% may have a subsegmental defect (with 95% confidence). Therefore, our study indicated that Q scan defects, particularly lobar or segmental, are rarely present among normal nonsmokers in this age group.

  6. The effects of continuous phonation on 133xenon-inhalation air curves (of the kind used in deriving regional cerebral blood flow).

    PubMed

    Formby, C; Thomas, R G; Brown, W S; Halsey, J H

    1987-07-01

    Regional cerebral blood flow (rCBF) may be measured with inhalation techniques that use end-expired values of radioactivity to estimate the isotope concentration in arterial blood. These end-expired data are used as an input function in a mathematical equation to derive rCBF. End-expired air is assumed normally to be in equilibrium with the arterial blood at the alveolar surface of the lung during regular (passive) breathing; this assumption may not be valid during continuous phonation. We therefore have analyzed breathing (inhalation/exhalation) patterns and end-expired radioactivity (133Xe) during (1) speaking, (2) singing, and (3) humming of the national anthem, and also during (4) passive breathing. Statistically significant differences in breathing patterns were measured between a group of nonmusicians and two groups of musicians (singers) during the phonation tasks: The nonmusicians breathed more often (and more rapidly) and exhibited less variability in their breathing patterns than did the musicians. Notwithstanding these differences, the shapes of smoothed functions derived from the end-expired values were not influenced appreciably during phonation (except possibly during talking). The latter finding suggests that estimates of rCBF derived with these data should not be confounded seriously because of the continuous phonation.

  7. Cardiovascular reflexes during rest and exercise modified by gravitational stresses

    NASA Astrophysics Data System (ADS)

    Bonde-petersen, Flemming

    The hypotheses tested were whether variations in central venous pressure via the low pressure baroreceptors would take over or modify the arterial baroreceptor function, and further to which extent local and "whole body" hydrostatic stresses influence blood flow distribution. We investigated total forearm and skin blood flow (venous occlusion plethysmography and 133-Xe clearance) and cardiac output (rebreathing method) among other parameters. Hypo-and hypergravitational stresses were simulated by LBNP, LBPP, water immersion and lowering of the arm. The changes in flow distribution in the arm were ascribed to arterial baroreceptor function and not to low pressure baroreceptor activity. The enhancement of venous return during water immersion increased exercise tolerance during heat stress presumably due both to increased stroke volume and decreased venous pooling. The response to sustained handgrip exercise during LBNP and LBPP was not different from control measurements and the effects explained by arterial baroreceptor function. Application of exercise and local hydrostatic stresses in combination with gravitational stresses represent an interesting model for further study of the mechanisms behind the distribution of cardiac output to the peripheral organs.

  8. Single-photon tomographic determination of regional cerebral blood flow in psychiatric disorders

    SciTech Connect

    Devous, M.D. Sr.; Rush, A.J.; Schlesser, M.A.; Debus, J.; Raese, J.D.; Chehabi, H.H.; Bonte, F.J.

    1984-01-01

    Regional cerebral blood flow (rCBF) was measured by single-photon emission computed tomography (SPECT) of 133-Xe washout in 29 normal volunteers, 22 unipolar endogenous depressives (UPE), 9 unipolar nonendogenous depressives (UPNE), 13 bipolar depressed patients (BPD), and 14 schizophrenic patients (SCHZ). RCBF was measured 2 and 6 cm above and parallel to the cantho-meatal line and quantitated in 14 gray matter regions. Most subjects were drug-free for 4-14 days. Diagnoses were made by experienced clinicians employing the Research Diagnostic Criteria, the Hamilton Rating Scale, and the dexamethasone suppression test. SCHZ were rated with the Brief Psychiatric Rating Scale. UPE had reduced flow compared to normals in the right parietal and temporal lobes and a nonsignificant trend toward left temporal flow reductions. UPNE were not different from normal or other patient groups. BPD had significant flow elevations in the left hemisphere relative to normal, and in both hemispheres relative to UPE. SCHZ were not significantly different from normal or other patient groups. Anterior-posterior flow shifts were evaluated by subtracting parietal or temporal flows from frontal flows. SCHZ demonstrated a greater posterior shift (lower relative frontal lobe flow) in comparison to both UPE and UPNE. The most significant regional flow abnormalities were observed as frontal flow reductions in individual SCHZ, although these were not significant in the whole group in comparison to normal.

  9. Plan for radionuclide tracer studies of the residence time distribution in the Wilsonville dissolver and preheater

    SciTech Connect

    Jolley, R.L.; Begovich, J.M.; Brashear, H.R.; Case, N.; Clark, T.G.; Emery, J.F.; Patton, B.D.; Rodgers, B.R.; Villiers-Fisher, J.F.; Watson, J.S.

    1983-12-01

    Stimulus-response measurements using radiotracers to measure residence time distribution (RTD) and hydrodynamic parameters for the preheaters and dissolvers at the Ft. Lewis Solvent Refined Coal (SRC) and the Exxon Donor Solvent (EDS) coal conversion pilot plants are reviewed. A plan is also presented for a series of radioactive tracer studies proposed for the Advanced Coal Liquefaction Facility at Wilsonville, Alabama, to measure the RTD for the preheater and dissolvers in the SRC-I mode. The tracer for the gas phase will be /sup 133/Xe, and /sup 198/Au (on carbonized resin or as an aqueous colloidal suspension) will be used as the slurry tracer. Four experimental phases are recommended for the RTD tracer studies: (1) preheater; (2) dissolver with 100% takeoff; (3) dissolver with 100% takeoff and solids withdrawal; and (4) dissolver with 50% takeoff. Eighteen gas-tracer and 22 liquid-tracer injections are projected to accomplish the four experimental phases. Two to four tracer injections are projected for preliminary tests to ensure the capability of safe injection of the radiotracers and the collection of statistically significant data. A complete projected cost and time schedule is provided, including procurement of necessary components, preparation of the radiotracers, assembly and testing of tracer injection apparatus and detection systems, onsite work and tracer injections, laboratory experimentation, data analysis, and report writing.

  10. Cerebral blood flow in patients (PTS) exposed to neurotoxic chemicals

    SciTech Connect

    Heuser, G.; Mena, I.; Thomas, C.

    1994-05-01

    Exposure to neurotoxic chemicals as pesticides, glues, solvents, etc. are known to induce neurologic and psychiatric symptomatology. We report on 72 pts, 33 young pts, 8 males, and 26 females, age 55 (7) yrs, 15 of them exposed to pesticides, and 37 to solvents. They were studied with quantitative and qualitative analysis of rCBF performed with 30 mCi of Xe-133 (Xe) by inhalation followed by 30 mCi of Tc-HMPAO given IV. Imaging was performed with a brain dedicated system, and distribution of rCBF was assessed with automatic ROI definition, and HMPAO normalized to maximal pixel activity in the brain. Results of Xe rCBF are expressed as mean and (S.D.) in ml/min/100g, and HMPAO as mean and (S.D.) uptake per ROI and compared with age-matched controls, 10 young and 20 elderly individuals, and also to a group of 36 elderly chronic fatigue pts (CFS), and 26 depression pts. CBF was diminished in young and elderly, 45 (7) and 40 (7) ml/min 100g, p<0.02 for both groups. Thus we conclude that pts exposed to chemicals present with diminished CBF, worse in elderly in the right dorsal frontal and parietal lobes, and in young, in left dorsal frontal and temporal lobes. These findings are significantly different from observations in pts and chronic fatigue and depression.

  11. (135)Xe measurements with a two-element CZT-based radioxenon detector for nuclear explosion monitoring.

    PubMed

    Ranjbar, Lily; Farsoni, Abi T; Becker, Eric M

    2017-04-01

    Measurement of elevated concentrations of xenon radioisotopes ((131m)Xe, (133m)Xe, (133)Xe and (135)Xe) in the atmosphere has been shown to be a very powerful method for verifying whether or not a detected explosion is nuclear in nature. These isotopes are among the few with enough mobility and with half-lives long enough to make their detection at long distances realistic. Existing radioxenon detection systems used by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) suffer from problems such as complexity, need for high maintenance and memory effect. To study the response of CdZnTe (CZT) detectors to xenon radioisotopes and investigate whether it is capable of mitigating the aforementioned issues with the current radioxenon detection systems, a prototype detector utilizing two coplanar CZT detectors was built and tested at Oregon State University. The detection system measures xenon radioisotopes through beta-gamma coincidence technique by detecting coincidence events between the two detectors. In this paper, we introduce the detector design and report our measurement results with radioactive lab sources and (135)Xe produced in the OSU TRIGA reactor. Minimum Detectable Concentration (MDC) for (135)Xe was calculated to be 1.47 ± 0.05 mBq/m(3).

  12. Cerebral circulatory and metabolic effects of 5-hydroxytryptamine in anesthetized baboons.

    PubMed Central

    Harper, M A; MacKenzie, E T

    1977-01-01

    1. The cerebral circulatory effects of the intracarotid administration of 5-hydroxytryptamine were examined in anaesthetized baboons. Cerebral blood flow was measured by the intracarotid 133Xe technique, cerebral O2 consumption and glucose uptake were measured as indices of brain metabolism and electrocortical activity was continuously monitored. 2. Despite a marked reduction in the calibre of the internal carotid artery (assessed angiographically), the intracarotid infusion of 5-hydroxytryptamine 0-1 microgram/kg. min did not effect any significant changes in cerebral blood flow, O2 consumption or glucose uptake. 3. Following transient osmotic disruption of the blood-brain barrier with the intracarotid infusion of hypertonic urea, the same dose of 5-hydroxytryptamine effected a marked reduction in cerebral blood flow from 51 +/- 2 to 36 +/- 2 ml./100 g. min (mean +/- S.E.; P less than 0-01). Both indices of cerebral metabolism were reduced significantly and the e.e.g. showed a more pronounced suppression-burst pattern. 4. We postulate that the cerebral circulatory responses to 5-hydroxytryptamine are dependent upon the integrity of the blood-brain barrier and the predominant effect of the intravascular administration of 5-hydroxytryptamine is on cortical activity or metabolism, rather than on cerebrovascular smooth muscle. Images Plate 1 PMID:411921

  13. Cognitive performance correlates with cerebrovascular impairments in multi-infarct dementia

    SciTech Connect

    Judd, B.W.; Meyer, J.S.; Rogers, R.L.; Gandhi, S.; Tanahashi, N.; Mortel, K.F.; Tawaklna, T.

    1986-05-01

    Cerebral blood flow (CBF) was measured by the /sup 133/Xe inhalation method in patients with multi-infarct dementia (MID, N = 26), Alzheimer's dementia (AD, N = 19), and among age-matched, neurologically normal, healthy volunteers (N = 26). Cognitive performance was assessed in all subjects using the Cognitive Capacity Screening Examination (CCSE). Cerebral vasomotor responses were calculated from differences in values of mean hemispheric gray matter blood flow (Delta CBF) measured during inhalation of 100% oxygen (hyperoxia) compared with CBF measured while breathing room air. Significant correlations were found between CCSE performance and vasomotor responsiveness in patients with MID (P less than .01), but not in patients with AD or in neurologically normal volunteers. Loss of vasomotor responsiveness is an indicator of cerebrovascular disease with rigidity and/or loss of reactivity of cerebral vessels, which impairs cerebrovascular responses to situational demands and predisposes to cerebral ischemia. Loss of cerebral vasomotor responsiveness among MID patients, which is a biologic marker of cerebrovascular disease, provides confirmatory evidence of the vascular etiology of MID and assists in separating MID from AD patients.

  14. Prospective analysis of long term control of mild hypertension on cerebral blood flow

    SciTech Connect

    Meyer, J.S.; Rogers, R.L.; Mortel, K.F.

    1985-11-01

    A group of 12 otherwise normal elderly volunteers (mean age = 69.8 years), were detected to have mild hypertension. Cerebral blood flow (CBF) values were measured using 133Xe inhalation method prior to initiating medical treatment and repeated at 6, 12, 24 and 36 months after BP was adequately controlled and restored to normal (below 150/90). Results indicate that CBF values increased markedly during follow-up intervals at 6, 12 and 24 months but not at 36 months. Hypertension is known to be a risk factor for stroke and 4 of the 12 subjects subsequently developed symptoms of cerebrovascular disease (stroke, multi-infarct dementia or transient ischemic attacks) despite control of hypertension. Analyses separating asymptomatic and symptomatic groups indicated that the eight asymptomatic patients continued to maintain increased CBF levels throughout the entire three year interval, whereas the 4 symptomatic patients developed declines in CBF which began, and progressively decreased below the initial pretreatment values, during the second and third years.

  15. A program to generate simulated radioxenon beta–gamma data for concentration verification and validation and training exercises

    SciTech Connect

    McIntyre, Justin I.; Schrom, Brian T.; Cooper, Matthew W.; Prinke, Amanda M.; Suckow, Thomas J.; Ringbom, Anders; Warren, Glen A.

    2016-03-08

    Abstract Several hundred simulated radioxenon beta-gamma data files were developed to assist in evaluating the performance and results from radioxenon concentration calculation analysis at the International Data Center (IDC) and other National Data Centers (NDC). PNNL developed a Beta-Gamma Simulator (BGSim) that incorporated GEANT-modeled data sets from radioxenon decay chains, as well as functionality to use nuclear detector-acquired data sets to create new beta-gamma spectra with varying amounts of background, 133Xe, 131mXe, 133mXe, 135Xe, and 222Rn and its decay products. The program has been implemented on a web-based applications platform and allows the user to create very specific data sets that incorporate most of the operational parameters for the current beta-gamma systems deployed in the International Monitoring System (IMS) and the On-site Inspection (OSI) equipment. After an initial beta-gamma simulations program was developed, additional uses began to be identified for the program output: training sets of two-dimensional spectra for data analysts at the IDC and other NDC, spectra for exercises such as the Integrated Field Exercise 2014 (IFE14) held in Jordan at the Dead Sea, and testing new analysis methods and algorithms

  16. Dynamic dose assessment by Large Eddy Simulation of the near-range atmospheric dispersion.

    PubMed

    Vervecken, Lieven; Camps, Johan; Meyers, Johan

    2015-03-01

    In order to improve the simulation of the near-range atmospheric dispersion of radionuclides, computational fluid dynamics is becoming increasingly popular. In the current study, Large-Eddy Simulation is used to examine the time-evolution of the turbulent dispersion of radioactive gases in the atmospheric boundary layer, and it is coupled to a gamma dose rate model that is based on the point-kernel method with buildup factors. In this way, the variability of radiological dose rate from cloud shine due to instantaneous turbulent mixing processes can be evaluated. The steady release in an open field of (41)Ar and (133)Xe for 4 different release heights is studied, thus covering radionuclides that decay with a high-energy gamma and a low-energy gamma, respectively. Based on these simulations, the variability of dose rates at ground level for different averaging times in the dose measurements is analyzed. It is observed that turbulent variability in the wind field can lead to dose estimates that are underestimated by up to a factor of four when conventional long-term measurements are used to estimate the dose from short-term exposures.

  17. Study of medical isotope production facility stack emissions and noble gas isotopic signature using automatic gamma-spectra analysis platform

    NASA Astrophysics Data System (ADS)

    Zhang, Weihua; Hoffmann, Emmy; Ungar, Kurt; Dolinar, George; Miley, Harry; Mekarski, Pawel; Schrom, Brian; Hoffman, Ian; Lawrie, Ryan; Loosz, Tom

    2013-04-01

    The nuclear industry emissions of the four CTBT (Comprehensive Nuclear-Test-Ban Treaty) relevant radioxenon isotopes are unavoidably detected by the IMS along with possible treaty violations. Another civil source of radioxenon emissions which contributes to the global background is radiopharmaceutical production companies. To better understand the source terms of these background emissions, a joint project between HC, ANSTO, PNNL and CRL was formed to install real-time detection systems to support 135Xe, 133Xe, 131mXe and 133mXe measurements at the ANSTO and CRL 99Mo production facility stacks as well as the CANDU (CANada Deuterium Uranium) primary coolant monitoring system at CRL. At each site, high resolution gamma spectra were collected every 15 minutes using a HPGe detector to continuously monitor a bypass feed from the stack or CANDU primary coolant system as it passed through a sampling cell. HC also conducted atmospheric monitoring for radioxenon at approximately 200 km distant from CRL. A program was written to transfer each spectrum into a text file format suitable for the automatic gamma-spectra analysis platform and then email the file to a server. Once the email was received by the server, it was automatically analysed with the gamma-spectrum software UniSampo/Shaman to perform radionuclide identification and activity calculation for a large number of gamma-spectra in a short period of time (less than 10 seconds per spectrum). The results of nuclide activity together with other spectrum parameters were saved into the Linssi database. This database contains a large amount of radionuclide information which is a valuable resource for the analysis of radionuclide distribution within the noble gas fission product emissions. The results could be useful to identify the specific mechanisms of the activity release. The isotopic signatures of the various radioxenon species can be determined as a function of release time. Comparison of 133mXe and 133Xe activity

  18. Fission Product Monitoring and Release Data for the Advanced Gas Reactor -1 Experiment

    SciTech Connect

    Dawn M. Scates; John B. Walter; Jason M. Harp; Mark W. Drigert; Edward L. Reber

    2010-10-01

    The AGR-1 experiment is a fueled multiple-capsule irradiation experiment that was irradiated in the Advanced Test Reactor (ATR) from December 26, 2006 until November 6, 2009 in support of the Very High Temperature Reactor (VHTR) Technology Development Office (TDO) Fuel Development and Qualification program. An important measure of the fuel performance is the quantification of the fission product releases over the duration of the experiment. To provide this data for the inert fission gasses(Kr and Xe), a fission product monitoring system (FPMS) was developed and implemented to monitor the individual capsule effluents for the radioactive species. The FPMS continuously measured the concentrations of various krypton and xenon isotopes in the sweep gas from each AGR-1 capsule to provide an indicator of fuel irradiation performance. Spectrometer systems quantified the concentrations of Kr-85m, Kr-87, Kr-88, Kr-89, Kr-90, Xe-131m, Xe-133, Xe 135, Xe 135m, Xe-137, Xe-138, and Xe-139 accumulated over repeated eight hour counting intervals.-. To determine initial fuel quality and fuel performance, release activity for each isotope of interest was derived from FPMS measurements and paired with a calculation of the corresponding isotopic production or birthrate. The release activities and birthrates were combined to determine Release-to-Birth ratios for the selected nuclides. R/B values provide indicators of initial fuel quality and fuel performance during irradiation. This paper presents a brief summary of the FPMS, the release to birth ratio data for the AGR-1 experiment and preliminary comparisons of AGR-1 experimental fuels data to fission gas release models.

  19. Influence of circulating epinephrine on absorption of subcutaneously injected insulin

    SciTech Connect

    Fernqvist, E.; Gunnarsson, R.; Linde, B.

    1988-06-01

    Effects of epinephrine (Epi) infusion on the absorption of subcutaneously injected 125I-labeled soluble human insulin (10 U) from the thigh or the abdomen were studied in 16 healthy subjects and from the thigh in 10 insulin-dependent diabetic (IDDM) patients. Epi was infused at 0.3 (high dose) or 0.1 (low dose; healthy subjects) nmol.kg-1.min-1 i.v., resulting in arterial plasma Epi levels of approximately 6 and 2 nM, respectively. Saline was infused on a control day. Insulin absorption was measured as disappearance of radioactivity from the injection site and as appearance of plasma immunoreactive insulin (IRI). Adipose tissue blood flow was measured with the 133Xe clearance technique. First-order disappearance rate constants of 125I from the thigh depot decreased approximately 40-50% during the high dose of Epi compared with control (P less than .001). The corresponding decrease from the abdominal depot was approximately 40% (P less than .001), whereas no significant change was found during the low Epi dose. IRI fell compared with control in all groups at the high Epi dose. The Epi-induced depression of insulin absorption occurred despite unaltered or even slightly increased subcutaneous blood flow. The results indicate that circulating Epi at levels seen during moderate physical stress depresses the absorption of soluble insulin from subcutaneous injection sites to an extent that might be important for glycemic control in IDDM patients. Furthermore, dissociation is found between changes in insulin absorption and subcutaneous blood flow during Epi infusion, suggesting that factors other than blood flow may also influence the absorption of subcutaneously injected insulin.

  20. Participation of the NDC Austria at the NDC Preparedness Exercise 2012

    NASA Astrophysics Data System (ADS)

    Mitterbauer, Ulrike; Wotawa, Gerhard; Schraick, Irene

    2013-04-01

    NDC Preparedness Exercises (NPEs) are conducted annually by the National Data Centers (NDCs) of CTBT States Signatories to train the detection of a (hypothetical) nuclear test. During the NDC Preparedness Exercise 2012, a fictitious radionuclide scenario originating from a real seismic event (mining explosion) was calculated by the German NDC and distributed among all NDCs. For the scenario computation, it was assumed that the selected seismic event was the epicentre of an underground nuclear fission explosion. The scenario included detections of the Iodine isotopes I-131 and I-133 (both particulates), and the Radioxenon Isotopes Xe-133, Xe-133M, Xe-131M and Xe-135 (noble gas). By means of atmospheric transport modelling (ATM), concentrations of all these six isotopes which would result from the hypothetical explosion were calculated and interpolated to the IMS station locations. The participating NDCs received information about the concentration of the isotopes at the station locations without knowing the underlying seismic event. The aim of the exercise was to identify this event based on the detection scenario. The Austrian NDC performed the following analyses: • Atmospheric backtracking and data fusion to identify seismic candidate events, • Seismic analysis of candidate events within the possible source region, • Atmospheric transport modelling (forward mode) from identified candidate events, comparison between "measured" and simulated concentrations based on certain release assumptions. The main goal of the analysis was to identify the event selected by NDC Germany to calculate the radionuclide scenario, and to exclude other events. In the presentation, the analysis methodology as well as the final results and conclusions will be shown and discussed in detail.

  1. The workshop on signatures of medical and industrial isotope production - WOSMIP; Strassoldo, Italy, 1-3 July 2009.

    PubMed

    Matthews, K M; Bowyer, T W; Saey, P R J; Payne, R F

    2012-08-01

    Radiopharmaceuticals make contributions of inestimable value to medical practice. With growing demand new technologies are being developed and applied worldwide. Most diagnostic procedures rely on (99m)Tc and the use of uranium targets in reactors is currently the favored method of production, with 95% of the necessary (99)Mo parent currently being produced by four major global suppliers. Coincidentally there are growing concerns for nuclear security and proliferation. New disarmament treaties such as the Comprehensive Nuclear-Test-Ban Treaty (CTBT) are coming into effect and treaty compliance-verification monitoring is gaining momentum. Radioxenon emissions (isotopes Xe-131, 133, 133m and 135) from radiopharmaceutical production facilities are of concern in this context because radioxenon is a highly sensitive tracer for detecting nuclear explosions. There exists, therefore, a potential for confusing source attribution, with emissions from radiopharmaceutical-production facilities regularly being detected in treaty compliance-verification networks. The CTBT radioxenon network currently under installation is highly sensitive with detection limits approaching 0.1 mBq/m³ and, depending on transport conditions and background, able to detect industrial release signatures from sites thousands of kilometers away. The method currently employed to distinguish between industrial and military radioxenon sources involves plots of isotope ratios (133m)Xe/(131m)Xe versus (135)Xe/(133)Xe, but source attribution can be ambiguous. Through the WOSMIP Workshop the environmental monitoring community is gaining a better understanding of the complexities of the processes at production facilities, and the production community is recognizing the impact their operations have on monitoring systems and their goal of nuclear non-proliferation. Further collaboration and discussion are needed, together with advances in Xe trapping technology and monitoring systems. Such initiatives will help

  2. Effects of clonidine on cerebral blood flow and the response to arterial CO2

    SciTech Connect

    Kanawati, I.S.; Yaksh, T.L.; Anderson, R.E.; Marsh, R.W.

    1986-06-01

    CBF, as measured by the clearance of /sup 133/Xe or /sup 85/Kr in the pentobarbital-anesthetized cat, displays a monotonic increase as the PaCO/sub 2/ is elevated over a range of 20-60 mm Hg (slope Xe, 1.65 +/- 0.14 ml/100g/min/mm Hg; slope Kr, 1.40 +/- 0.11 ml/100 g/min/mm Hg). Clonidine (20 micrograms/kg i.v.), a centrally acting, alpha 2-preferring agonist, reduced the slope of the PaCO/sub 2/-CBF response functions for Xe and Kr by 70 and 64%, respectively. Clonidine reduced normocarbic CBF-Xe by 36%, but had no effect on normocarbic CBF-Kr. ST-91, a polar structural analog of clonidine that does not cross the blood-brain barrier, did not reproduce the effects of clonidine when administered at an equivalent dose. This indicates that the effects of clonidine observed were secondary to its action on central rather than peripheral sites. In addition to the effects on the clearance of CBF markers, clonidine reduced the increased MABP otherwise evoked by elevated PaCO/sub 2/. Reduction in the MABP response to PaCO/sub 2/ did not account for the lowering of CBF during hypercarbia. In separate experiments where MABP was elevated to correspond with the PaCO/sub 2/-MABP response observed in the absence of clonidine, a comparable reduction in the slope of the PaCO/sub 2/ response was also observed. In addition, the pressure autoregulatory response was unaltered after clonidine treatment. These observations suggest that the central action of alpha 2-receptors on the CBF-CO/sub 2/ response cannot be attributed to an altered perfusion pressure.

  3. Negative neurofunctional effects of frequency, depth and environment in recreational scuba diving: the Geneva "memory dive" study

    PubMed Central

    Slosman, D; de Ribaupierre, S; Chicherio, C; Ludwig, C; Montandon, M; Allaoua, M; Genton, L; Pichard, C; Grousset, A; Mayer, E; Annoni, J; de Ribaupierre, A

    2004-01-01

    Objectives: To explore relationships between scuba diving activity, brain, and behaviour, and more specifically between global cerebral blood flow (CBF) or cognitive performance and total, annual, or last 6 months' frequencies, for standard dives or dives performed below 40 m, in cold water or warm sea geographical environments. Methods: A prospective cohort study was used to examine divers from diving clubs around Lac Léman and Geneva University Hospital. The subjects were 215 healthy recreational divers (diving with self-contained underwater breathing apparatus). Main outcome measures were: measurement of global CBF by 133Xe SPECT (single photon emission computed tomography); psychometric and neuropsychological tests to assess perceptual-motor abilities, spatial discrimination, attentional resources, executive functioning, and memory; evaluation of scuba diving activity by questionnaire focusing on number and maximum depth of dives and geographical site of the diving activity (cold water v warm water); and body composition analyses (BMI). Results: (1) A negative influence of depth of dives on CBF and its combined effect with BMI and age was found. (2) A specific diving environment (more than 80% of dives in lakes) had a negative effect on CBF. (3) Depth and number of dives had a negative influence on cognitive performance (speed, flexibility and inhibition processing in attentional tasks). (4) A negative effect of a specific diving environment on cognitive performance (flexibility and inhibition components) was found. Conclusions: Scuba diving may have long-term negative neurofunctional effects when performed in extreme conditions, namely cold water, with more than 100 dives per year, and maximal depth below 40 m. PMID:15039241

  4. Cerebral blood flow decreases with time whereas cerebral oxygen consumption remains stable during hypothermic cardiopulmonary bypass in humans

    SciTech Connect

    Prough, D.S.; Rogers, A.T.; Stump, D.A.; Roy, R.C.; Cordell, A.R.; Phipps, J.; Taylor, C.L. )

    1991-02-01

    Recent investigations demonstrate that cerebral blood flow (CBF) progressively declines during hypothermic, nonpulsatile cardiopulmonary bypass (CPB). If CBF declines because of brain cooling, the cerebral metabolic rate for oxygen (CMRO2) should decline in parallel with the reduction in CBF. Therefore we studied the response of CBF, the cerebral arteriovenous oxygen content difference (A-VDcereO2) and CMRO2 as a function of the duration of CPB in humans. To do this, we compared the cerebrovascular response to changes in the PaCO2. Because sequential CBF measurements using xenon 133 (133Xe) clearance must be separated by 15-25 min, we hypothesized that a time-dependent decline in CBF would accentuate the CBF reduction caused by a decrease in PaCO2, but would blunt the CBF increase associated with a rise in PaCO2. We measured CBF in 25 patients and calculated the cerebral arteriovenous oxygen content difference using radial arterial and jugular venous bulb blood samples. Patients were randomly assigned to management within either a lower (32-48 mm Hg) or higher (50-71 mm Hg) range of PaCO2 uncorrected for temperature. Each patient underwent two randomly ordered sets of measurements, one at a lower PaCO2 and the other at a higher PaCO2 within the respective ranges. Cerebrovascular responsiveness to changes in PaCO2 was calculated as specific reactivity (SR), the change in CBF divided by the change in PaCO2, expressed in mL.100 g-1.min-1.mm Hg-1.

  5. Cerebral autoregulation and flow/metabolism coupling during cardiopulmonary bypass: the influence of PaCO/sub 2/

    SciTech Connect

    Murkin, J.M.; Farrar, J.K.; Tweed, W.A.; McKenzie, F.N.; Guiraudon, G.

    1987-09-01

    Measurement of /sup 133/Xe clearance and effluent cerebral venous blood sampling were used in 38 patients to determine the effects of cardiopulmonary bypass, and of maintaining temperature corrected or noncorrected PaCO/sub 2/ at 40 mm Hg on regulation of cerebral blood flow (CBF) and flow/metabolism coupling. After induction of anesthesia with diazepam and fentanyl, mean CBF was 25 ml X 100 g-1 X min-1 and cerebral oxygen consumption, 1.67 ml X 100 g-1 X min-1. Cerebral oxygen consumption during nonpulsatile cardiopulmonary bypass at 26 degrees C was reduced to 0.42 ml X 100 g-1 X min-1 in both groups. CBF was reduced to 14-15 ml X 100 g-1 X min-1 in the non-temperature-corrected group (n = 21), was independent of cerebral perfusion pressure over the range of 20-100 mm Hg, but correlated with cerebral oxygen consumption. In the temperature-corrected group (n = 17), CBF varied from 22 to 32 ml X 100 g-1 X min-1, and flow/metabolism coupling was not maintained (i.e., CBF and cerebral oxygen consumption varied independently). However, variation in CBF correlated significantly with cerebral perfusion pressure over the pressure range of 15-95 mm Hg. This study demonstrates a profound reduction in cerebral oxygen consumption during hypothermic nonpulsatile cardiopulmonary bypass. When a non-temperature-corrected PaCO/sub 2/ of approximately 40 mm Hg was maintained, CBF was lower, and analysis of pooled data suggested that CBF regulation was better preserved, i.e., CBF was independent of pressure changes and dependent upon cerebral oxygen consumption.

  6. Regional pulmonary blood flow in sitting and supine man during and after acute hypoxia

    PubMed Central

    Dawson, Arthur

    1969-01-01

    Regional pulmonary blood flow was measured by external counting of intravenously injected 133Xe during 20 min of breathing 14.2% oxygen and during 20 min of recovery from hypoxia. 16 normal human volunteers were studied, nine sitting and seven supine. During hypoxia there was a slight but significant increase in relative perfusion of the upper portions of the lungs in both the sitting and supine subjects. During recovery from hypoxia, blood flow distribution differed significantly from the control. The erect subjects showed increased relative perfusion of the lung bases and the supine subjects showed increased relative perfusion of the upper zones. Comparison of the distribution of inhaled and intravenously injected isotope showed that in the sitting subjects the altered distribution during hypoxia tended to make alveolar oxygen tension more uniform. In the supine subjects, however, the shift in blood flow increased the perfusion of the regions with the lowest ventilation/perfusion, tending to accentuate uneven alveolar oxygen tension. Therefore it does not seem that the altered blood flow distribution during hypoxia was due to selective vasoconstriction in the regions of lowest alveolar oxygen tension, but rather that vasoconstriction was greatest in the lower lung zones because the vessels there are more responsive to hypoxia. During mild acute hypoxia, vasoconstrictor tone does not seem to effectively match ventilation and perfusion. The altered distribution of pulmonary blood flow during recovery from hypoxia suggests the occurrence of posthypoxic vasodilation. Failure to consider this possibility may lead to erroneous interpretation of pulmonary hemodynamic measurements made after the inspired oxygen concentration has been changed. PMID:5764012

  7. Cerebral circulation in hypoxia and ischemia.

    PubMed

    Kovách, A G

    1988-01-01

    In conclusion our results clearly suggest that vital functions of the brain, in spite of its well developed autoregulation are impaired during prolonged hypovolemic conditions. Regional cerebral blood flow measured by the 133Xe clearance and 14C-antipyrine autoradiographic techniques demonstrated a progressive reduction in CBF, with the development of patchy and circumscribed ischemic areas during hemorrhagic shock which persisted after reinfusion. The regional distribution of the underperfused regions cannot be explained solely in terms of boundary zones between the main distribution fields of major cerebral arteries. Our results suggest the involvement of the sympathetic nervous system in the impairment of cerebral microcirculation during hemorrhagic shock. The patchy focal brain damage could be the background of the functional impairment. The focal appearances suggests that, in addition to generalized (blood borne) changes, local factors play an important role in the production of ischemic areas in the brain. Afferent neural nociceptive input to the brain seems to be elevated during shock. It may be presumed that this leads to increased tissue metabolism and the accumulation of metabolites. The low flow combined with elevated neuronal activity and cellular metabolism produces an imbalance between oxygen delivery and oxygen utilization. The local nature of afferent activation of the CNS can explain the regional impairment in the brain tissue. Nociceptive afferent stimulation increases, while denervation of the carotid sinus or transsection of the vagus or spinal afferent pathways decreases the sensitivity to shock. We have presented further evidence that stimulation of the C-fibres of the sciatic nerve reduced local cerebral blood flow and the tissue PO2 in the n. VPL thalami and VM hypothalami in cardiovascularly restricted (stabilized blood pressure) animals. Concerning the subcellular events that may lead to neuronal death during hemorrhagic shock, we believe

  8. International challenge to predict the impact of radioxenon releases from medical isotope production on a comprehensive nuclear test ban treaty sampling station.

    PubMed

    Eslinger, Paul W; Bowyer, Ted W; Achim, Pascal; Chai, Tianfeng; Deconninck, Benoit; Freeman, Katie; Generoso, Sylvia; Hayes, Philip; Heidmann, Verena; Hoffman, Ian; Kijima, Yuichi; Krysta, Monika; Malo, Alain; Maurer, Christian; Ngan, Fantine; Robins, Peter; Ross, J Ole; Saunier, Olivier; Schlosser, Clemens; Schöppner, Michael; Schrom, Brian T; Seibert, Petra; Stein, Ariel F; Ungar, Kurt; Yi, Jing

    2016-06-01

    The International Monitoring System (IMS) is part of the verification regime for the Comprehensive Nuclear-Test-Ban-Treaty Organization (CTBTO). At entry-into-force, half of the 80 radionuclide stations will be able to measure concentrations of several radioactive xenon isotopes produced in nuclear explosions, and then the full network may be populated with xenon monitoring afterward. An understanding of natural and man-made radionuclide backgrounds can be used in accordance with the provisions of the treaty (such as event screening criteria in Annex 2 to the Protocol of the Treaty) for the effective implementation of the verification regime. Fission-based production of (99)Mo for medical purposes also generates nuisance radioxenon isotopes that are usually vented to the atmosphere. One of the ways to account for the effect emissions from medical isotope production has on radionuclide samples from the IMS is to use stack monitoring data, if they are available, and atmospheric transport modeling. Recently, individuals from seven nations participated in a challenge exercise that used atmospheric transport modeling to predict the time-history of (133)Xe concentration measurements at the IMS radionuclide station in Germany using stack monitoring data from a medical isotope production facility in Belgium. Participants received only stack monitoring data and used the atmospheric transport model and meteorological data of their choice. Some of the models predicted the highest measured concentrations quite well. A model comparison rank and ensemble analysis suggests that combining multiple models may provide more accurate predicted concentrations than any single model. None of the submissions based only on the stack monitoring data predicted the small measured concentrations very well. Modeling of sources by other nuclear facilities with smaller releases than medical isotope production facilities may be important in understanding how to discriminate those releases from

  9. Regulation of local subcutaneous blood flow in patients with psoriasis and effects of antipsoriatic treatment on subcutaneous blood flow

    SciTech Connect

    Klemp, P.

    1985-08-01

    Local regulation of the doubled subcutaneous blood flow (SBF) rates in psoriatic lesional skin was studied in 8 patients using a traumatic epicutaneous /sup 133/Xe labeling washout technique. Venous stasis of 40 mm Hg induced a significant reduction in the SBF (-34%, p less than 0.01), i.e., a normal vasoconstrictor response. Limb elevation of 40 cm above heart level induced no statistical changes in the SBF (p = 0.50), i.e., a normal local autoregulation response. This indicates normal, local regulation mechanisms of SBF in psoriasis. In another 8 patients, the effect on SBF of a 4-week antipsoriatic treatment with tar was studied in lesional and symmetrically nonlesional skin areas. One patient was clear of psoriasis on day 22, and was followed only to that time. The mean pretreatment SBF in lesional skin areas was 3.87 +/- SD 0.78 ml X (100 g X min)-1, which was not statistically different from measurements on days 3, 7, 14, and 21 after treatment had started. Between day 21 and day 28, the SBF decreased significantly to 3.38 +/- SD 0.78 ml X (100 g X min)-1, p less than 0.05. The difference between the pretreatment SBF and SBF at the end of treatment was statistically significant, p less than 0.05. The changes in SBF in symmetrically nonlesional skin areas were statistically nonsignificant during the period of treatment. Pretreatment SBF was 2.60 +/- SD 1.08 (N = 8), and on day 28 was 1.91 +/- SD 0.74 ml X (100 g X min)-1 (N = 7). However, the tendency of a decreasing SBF at the end of treatment was a clear trend, since SBF in 6 of 7 patients decreased during the third week and in the patient who was discharged on day 22, a decrease in the SBF was observed on days 14 and 21.

  10. Technegas: A medical application of {sup 99m}Tc for the study of buckyballs, blood clots, lung disease and AIDS

    SciTech Connect

    Willett, G.D.; Dance, I.G.; Fisher, K.J.; Burch, W.M.; Dasaklis, C.; Mackey, D.W.J.

    1994-12-31

    Radionuclide studies of lung disease have been greatly enhanced by the introduction of an Australian invention; the Technegas generator. The properties of the {open_quotes}dry radio-aerosols{close_quotes} produced by this device ensure lung images superior to those from true radio-gases such as {sup 133}Xe with the additional advantage of employing {sup 99m}Tc, the most widespread radionuclide agent. A Technegas lung scan can enable identification of pulmonary mebolism (an immediately life threatening condition) emphysema and chronic obstructive lung disease. A simple modification to the generator gas mixture produces Pertechnegas an agent useful in studies of the integrity of the alveolar epithelial membrane in immunosuppressed patients such as transplants and AIDS. Although these agents are now common in Australia and Europe, little has been proven of their chemical composites. Technegas is formed by the initial evaporation of ({sup 99m}Tc) sodium pertechnetate with the subsequent sublimation of carbon from a disposable graphite crucible at {approximately}2500{degrees}C in an atmosphere of 100% argon. {sup 99m}Tc atoms are lifted off with the crystalline layers of graphite during the vaporization. Technegas then possibly consists of {sup 99m}Tc based metallo-fullerenes and fullerenes. Technegas has an effective half life in the lung very similar to the physical half life of Technetium (6 hours) regardless of clinical condition; a result which suggests that Technegas contains endohedral fullerenes. Pertechnegas is created in an atmosphere of 97% Ar 3% O{sub 2} and has an effective half life in the lung of less than 15 minutes.

  11. Sympathetic reflex control of skeletal muscle blood flow in patients with congestive heart failure: evidence for beta-adrenergic circulatory control

    SciTech Connect

    Kassis, E.; Jacobsen, T.N.; Mogensen, F.; Amtorp, O.

    1986-11-01

    Mechanisms controlling forearm muscle vascular resistance (FMVR) during postural changes were investigated in seven patients with severe congestive heart failure (CHF) and in seven control subjects with unimpaired left ventricular function. Relative brachioradial muscle blood flow was determined by the local /sup 133/Xe-washout technique. Unloading of baroreceptors with use of 45 degree upright tilt was comparably obtained in the patients with CHF and control subjects. Control subjects had substantially increased FMVR and heart rate to maintain arterial pressure whereas patients with CHF had decreased FMVR by 51 +/- 11% and had no increase in heart rate despite a fall in arterial pressure during upright tilt. The autoregulatory and local vasoconstrictor reflex responsiveness during postural changes in forearm vascular pressures were intact in both groups. In the patients with CHF, the left axillary nerve plexus was blocked by local anesthesia. No alterations in forearm vascular pressures were observed. This blockade preserved the local regulation of FMVR but reversed the vasodilator response to upright tilt as FMVR increased by 30 +/- 7% (p less than .02). Blockade of central neural impulses to this limb combined with brachial arterial infusions of phentolamine completely abolished the humoral vasoconstriction in the tilted position. Infusions of propranolol to the contralateral brachial artery that did not affect baseline values of heart rate, arterial pressure, or the local reflex regulation of FMVR reversed the abnormal vasodilator response to upright tilt as FMVR increased by 42 +/- 12% (p less than .02). Despite augmented baseline values, forearm venous but not arterial plasma levels of epinephrine increased in the tilted position, as did arteri rather than venous plasma concentrations of norepinephrine in these patients.

  12. Effects of midazolam on cerebral blood flow in human volunteers

    SciTech Connect

    Forster, A.; Juge, O.; Morel, D.

    1982-06-01

    The effects of intravenously administered midazolam on cerebral blood flow were evaluated in eight healthy volunteers using the /sup 133/Xe inhalation technique. Six minutes after an intravenous dose of 0.15 mg/kg midazolam, the cerebral blood flow decreased significantly (P less than 0.001) from a value of 40.6 +/- 3.3 to a value of 27.0 +/- 5.0 ml . 100 g-1 . min-1. Cerebrovascular resistance (CVR) increased from 2.8 +/- 0.2 to 3.9 to 0.6 mmHg/(ml . 100 g-1 . min-1)(P less than 0.001). Mean arterial blood pressure decreased significantly (P less than 0.05) from 117 +/- 8 to 109 +/- 9 mmHg and arterial carbon dioxide tension increased from 33.9 +/- 2.3 to 38.6 +/- 3.2 mmHg (P less than 0.05). Arterial oxygen tension remained stable throughout the study, 484 +/- 95 mmHg before the administration of midazolam and 453 +/- 76 mmHg after. All the subjects slept after the injection of the drug and had anterograde amnesia of 24.5 +/- 5 min. The decrease in mean arterial blood pressure was probably not important since it remained in the physiologic range for cerebral blood flow autoregulation. The increase in arterial carbon dioxide tension observed after the midazolam injection may have partially counteracted the effect of this new benzodiazepine on cerebral blood flow. Our data suggest that midazolam might be a safe agent to use for the induction of anethesia in neurosurgical patients with intracranial hypertension.

  13. Retention of {sup 99m}{Tc}-bicisate in the human brain after intracarotid injection

    SciTech Connect

    Friberg, L.; Lassen, N.A.; Andersen, A.R.; Dam, M.

    1994-01-01

    {sup 99m}{Tc}-bicisate (ECD) was injected as a bolus into the internal carotid artery, and cerebral uptake and retention were recorded with fast-rotating single photon emission computed tomography (SPECT) equipment in four patients suffering from temporal lobe epilepsy. Quantitative regional cerebral blood flow (rCBF) was measured tomographically with the {sup 133}Xe inhalation technique. The authors applied a three-compartment kinetic model and algorithms modified from a previous analysis of {sup 99m}{Tc} d,l-hexamethylpropyleneamine oxide (HM-PAO) kinetics. The bicisate brain uptake and retention curve was very similar to that of HM-PAO, and it can be described by a triexponential function including an initial steep component representing the vascular transmitted spike, a second less steep component representing back-diffusion from brain tissue to blood, and a third, very slow component, representing the very slow loss due to incomplete retention of the deesterified hydrophilic metabolites. Computerized curve-fitting on data from three patients gave average kinetic values for the first-passage (unilateral) extraction of E = 0.60 (range, 0.59-0.61); the overall retained fraction of the tracer supplied was R = 0.44 (0.43-0.45), and the conversion/clearance ratio was {alpha} = k{sub 3}/k{sub 2} = 2.59 (2.38-2.77). This {alpha} is higher than that for HM-PAO, and therefore bicisate uptake as a function of blood flow is more linear than in HM-PAO. Less correction for backdiffusion is therefore needed. From 1 to 24 h there was an average loss of hydrophilic tracer of 3.5%/h, but the late distribution images were essentially unchanged over time, pointing to practically the same rate of loss in all regions. 18 refs., 5 figs., 2 tabs.

  14. Unexpected bias in NIST 4πγ ionization chamber measurements.

    PubMed

    Unterweger, M P; Fitzgerald, R

    2012-09-01

    In January of 2010, it was discovered that the source holder used for calibrations in the NIST 4πγ ionization chamber (IC) has not been stable. The positioning ring that determines the height of the sample in the reentrant tube of the IC has slowly shifted during 35 years of use. This has led to a slow change in the calibration factors for the various radionuclides measured by this instrument. The changes are dependent on γ-ray energy and the time the IC was calibrated for a given radionuclide. A review of the historic data with regard to when the calibrations were done has enabled us to approximate the magnitude of the changes with time. This requires a number of assumptions, and corresponding uncertainty components, including whether the changes in height were gradual or in steps as will be shown in drawings of sample holder. For calibrations the changes in calibration factors have been most significant for low energy gamma emitters such as (133)Xe, (241)Am, (125)I and (85)Kr. The corrections to previous calibrations can be approximated and the results corrected with an increase in the overall uncertainty. At present we are recalibrating the IC based on new primary measurements of the radionuclides measured on the IC. Likewise we have been calibrating a new automated ionization-chamber system. A bigger problem is the significant number of half-life results NIST has published over the last 35 years that are based on IC measurements. The effect on half-life is largest for long-lived radionuclei, especially low-energy γ-ray emitters. This presentation will review our results and recommend changes in values and/or uncertainties. Any recommendation for withdrawal of any results will also be undertaken.

  15. Depth discrimination in acousto-optic cerebral blood flow measurement simulation

    NASA Astrophysics Data System (ADS)

    Tsalach, A.; Schiffer, Z.; Ratner, E.; Breskin, I.; Zeitak, R.; Shechter, R.; Balberg, M.

    2016-03-01

    Monitoring cerebral blood flow (CBF) is crucial, as inadequate perfusion, even for relatively short periods of time, may lead to brain damage or even death. Thus, significant research efforts are directed at developing reliable monitoring tools that will enable continuous, bed side, simple and cost-effective monitoring of CBF. All existing non invasive bed side monitoring methods, which are mostly NIRS based, such as Laser Doppler or DCS, tend to underestimate CBF in adults, due to the indefinite effect of extra-cerebral tissues on the obtained signal. If those are to find place in day to day clinical practice, the contribution of extra-cerebral tissues must be eliminated and data from the depth (brain) should be extracted and discriminated. Recently, a novel technique, based on ultrasound modulation of light was developed for non-invasive, continuous CBF monitoring (termed ultrasound-tagged light (UTL or UT-NIRS)), and shown to correlate with readings of 133Xe SPECT and laser Doppler. We have assembled a comprehensive computerized simulation, modeling this acousto-optic technique in a highly scattering media. Using the combination of light and ultrasound, we show how depth information may be extracted, thus distinguishing between flow patterns taking place at different depths. Our algorithm, based on the analysis of light modulated by ultrasound, is presented and examined in a computerized simulation. Distinct depth discrimination ability is presented, suggesting that using such method one can effectively nullify the extra-cerebral tissues influence on the obtained signals, and specifically extract cerebral flow data.

  16. A vented inverted fuel assembly design for an SFR

    SciTech Connect

    Vitillo, F.; Todreas, N. E.; Driscoll, M. J.

    2012-07-01

    The inverted geometry (fuel outside coolant tubes) has been previously investigated at MIT for application in gas-cooled fast reactors and pressurized water-cooled thermal reactors. Venting has also been studied for conventional fuel pins and was employed for those in the Dounreay Fast Reactor. In the present work the inverted fuel approach was adopted because it allows high fuel volume fraction, reduction of the coolant void reactivity, neutron leakage and enrichment, as well as lower pressure drop for the same channel length because grids and wire wraps are no longer necessary. Furthermore most results also apply to venting of conventional fuel pins. Physical and chemical behavior of volatile fission products in sodium was investigated to determine the maximum activity inventory which would eventually be released into the primary sodium. Results of this analysis show that the most troublesome radionuclides in terms of propensity to escape from the venting system are noble gases ({sup 85}Kr and {sup 133}Xe), and cesium ({sup 134}Cs and {sup 137}Cs). A final vented inverted fuel assembly design is proposed which meets all the design goals which have been set. Additionally purification systems were devised to reduce radionuclide activity of the coolant and the cover gas to tolerable levels. It is concluded that vented inverted (or vented conventional pin) fuel is a feasible concept and has sufficiently promising advantages - increasing fuel volume fraction to 50% and core outlet temperature by 20 deg. C, hence incrementing plant thermal efficiency by about 1% - to warrant serious consideration for future SFR designs. (authors)

  17. Assessment of demented patients by dynamic SPECT of inhaled xenon-133

    SciTech Connect

    Komatani, A.; Yamaguchi, K.; Sugai, Y.; Takanashi, T.; Kera, M.; Shinohara, M.; Kawakatsu, S.

    1988-10-01

    We studied the potential for using dynamic single photon emission computed tomography of inhaled xenon-133 (/sup 133/Xe) gas in the assessment of demented patients. An advanced ring-type single photon emission computed tomography (SPECT) HEADTOME with improved spatial resolution (15 mm in full width at half maximum (FWHM)) was used for tomographic measurement of regional cerebral blood flow (rCBF). All 34 patients underwent a detailed psychiatric examination and x-ray computed tomography scan, and matched research criteria for Alzheimer's disease (n = 13), senile dementia of the Alzheimer type (n = 9), or multi-infarct dementia (n = 12). In comparison with a senile control group (n = 7), mean CBF of both the whole brain and the temporo-parietal region was significantly less in the Alzheimer's disease and senile dementia Alzheimer type groups, but no significant difference was seen between the senile control group and multi-infarct dementia group. The correlation was 0.72 (p less than 0.004) between the mean CBF of the whole brain and the score of Hasegawa's Dementia Scale, and 0.94 (p less than 0.0001) between rCBF of the temporo-parietal region and the scale in Alzheimer's disease. In the senile dementia Alzheimer type group, the correlations were 0.77 (p less than 0.01) and 0.83 (p less than 0.004) respectively. No significant correlations were found in the multi-infarct dementia group. A temporo-parietal reduction in the distribution of the rCBF characteristic in the Alzheimer's disease group and a patchy whole brain reduction characteristic in the multi-infarct dementia group was detected. The ability of our improved SPECT to provide both quantitative measurement of rCBF and characteristic rCBF distribution patterns, makes it a promising tool for research or routine examination of demented patients.

  18. Innovative concept for a major breakthrough in atmospheric radioactive xenon detection for nuclear explosion monitoring.

    PubMed

    Le Petit, G; Cagniant, A; Morelle, M; Gross, P; Achim, P; Douysset, G; Taffary, T; Moulin, C

    The verification regime of the comprehensive test ban treaty (CTBT) is based on a network of three different waveform technologies together with global monitoring of aerosols and noble gas in order to detect, locate and identify a nuclear weapon explosion down to 1 kt TNT equivalent. In case of a low intensity underground or underwater nuclear explosion, it appears that only radioactive gases, especially the noble gas which are difficult to contain, will allow identification of weak yield nuclear tests. Four radioactive xenon isotopes, (131m)Xe, (133m)Xe, (133)Xe and (135)Xe, are sufficiently produced in fission reactions and exhibit suitable half-lives and radiation emissions to be detected in atmosphere at low level far away from the release site. Four different monitoring CTBT systems, ARIX, ARSA, SAUNA, and SPALAX™ have been developed in order to sample and to measure them with high sensitivity. The latest developed by the French Atomic Energy Commission (CEA) is likely to be drastically improved in detection sensitivity (especially for the metastable isotopes) through a higher sampling rate, when equipped with a new conversion electron (CE)/X-ray coincidence spectrometer. This new spectrometer is based on two combined detectors, both exhibiting very low radioactive background: a well-type NaI(Tl) detector for photon detection surrounding a gas cell equipped with two large passivated implanted planar silicon chips for electron detection. It is characterized by a low electron energy threshold and a much better energy resolution for the CE than those usually measured with the existing CTBT equipments. Furthermore, the compact geometry of the spectrometer provides high efficiency for X-ray and for CE associated to the decay modes of the four relevant radioxenons. The paper focus on the design of this new spectrometer and presents spectroscopic performances of a prototype based on recent results achieved from both radioactive xenon standards and air sample

  19. An inverse modeling method to assess the source term of the Fukushima nuclear power plant accident using gamma dose rate observations

    NASA Astrophysics Data System (ADS)

    Saunier, O.; Mathieu, A.; Didier, D.; Tombette, M.; Quélo, D.; Winiarek, V.; Bocquet, M.

    2013-06-01

    The Chernobyl nuclear accident and more recently the Fukushima accident highlighted that the largest source of error on consequences assessment is the source term including the time evolution of the release rate and its distribution between radioisotopes. Inverse modeling methods, which combine environmental measurements and atmospheric dispersion models, have proven efficient in assessing source term due to an accidental situation (Gudiksen, 1989; Krysta and Bocquet, 2007; Stohl et al., 2012a; Winiarek et al., 2012). Most existing approaches are designed to use air sampling measurements (Winiarek et al., 2012) and some of them also use deposition measurements (Stohl et al., 2012a; Winiarek et al., 2013) but none of them uses dose rate measurements. However, it is the most widespread measurement system, and in the event of a nuclear accident, these data constitute the main source of measurements of the plume and radioactive fallout during releases. This paper proposes a method to use dose rate measurements as part of an inverse modeling approach to assess source terms. The method is proven efficient and reliable when applied to the accident at the Fukushima Daiichi nuclear power plant (FD-NPP). The emissions for the eight main isotopes 133Xe, 134Cs, 136Cs, 137Cs, 137mBa, 131I, 132I and 132Te have been assessed. Accordingly, 103 PBq of 131I, 35.5 PBq of 132I, 15.5 PBq of 137Cs and 12 100 PBq of noble gases were released. The events at FD-NPP (such as venting, explosions, etc.) known to have caused atmospheric releases are well identified in the retrieved source term. The estimated source term is validated by comparing simulations of atmospheric dispersion and deposition with environmental observations. The result is that the model-measurement agreement for all of the monitoring locations is correct for 80% of simulated dose rates that are within a factor of 2 of the observed values. Changes in dose rates over time have been overall properly reconstructed, especially

  20. Peak muscle perfusion and oxygen uptake in humans: importance of precise estimates of muscle mass.

    PubMed

    Râdegran, G; Blomstrand, E; Saltin, B

    1999-12-01

    The knee extensor exercise model was specifically developed to enable in vivo estimates of peak muscle blood flow and O(2) uptake in humans. The original finding, using thermodilution measurements to measure blood flow in relation to muscle mass [P. Andersen and B. Saltin. J. Physiol. (Lond.) 366: 233-249, 1985], was questioned, however, as the measurements were two- to threefold higher than those previously obtained with the (133)Xe clearance and the plethysmography technique. As thermodilution measurements have now been confirmed by other methods and independent research groups, we aimed to address the impact of muscle mass estimates on the peak values of muscle perfusion and O(2) uptake. In the present study, knee extensor volume was determined from multiple measurements with computer tomography along the full length of the muscle. In nine healthy humans, quadriceps muscle volume was 2.36 +/- 0.17 (range 1. 31-3.27) liters, corresponding to 2.48 +/- 0.18 (range 1.37-3.43) kg. Anthropometry overestimated the muscle volume by approximately 21-46%, depending on whether quadriceps muscle length was estimated from the patella to either the pubic bone, inguinal ligament, or spina iliaca anterior superior. One-legged, dynamic knee extensor exercise up to peak effort of 67 +/- 7 (range 55-100) W rendered peak values for leg blood flow (thermodilution) of 5.99 +/- 0.66 (range 4.15-9.52) l/min and leg O(2) uptake of 856 +/- 109 (range 590-1,521) ml/min. Muscle perfusion and O(2) uptake reached peak values of 246 +/- 24 (range 149-373) and 35.2 +/- 3.7 (range 22.6-59. 6) ml. min(-1). 100 g muscle(-1), respectively. These peak values are approximately 19-33% larger than those attained by applying anthropometric muscle mass estimates. In conclusion, the present findings emphasize that peak perfusion and O(2) uptake in human skeletal muscle may be up to approximately 30% higher than previous anthropometric-based estimates that use equivalent techniques for blood flow

  1. Diabetic patients have abnormal cerebral autoregulation during cardiopulmonary bypass

    SciTech Connect

    Croughwell, N.; Lyth, M.; Quill, T.J.; Newman, M.; Greeley, W.J.; Smith, L.R.; Reves, J.G. )

    1990-11-01

    We tested the hypothesis that insulin-dependent diabetic patients with coronary artery bypass graft surgery experience altered coupling of cerebral blood flow and oxygen consumption. In a study of 23 patients (11 diabetics and 12 age-matched controls), cerebral blood flow was measured using 133Xe clearance during nonpulsatile, alpha-stat blood gas managed cardiopulmonary bypass at the conditions of hypothermia and normothermia. In diabetic patients, the cerebral blood flow at 26.6 +/- 2.42 degrees C was 25.3 +/- 14.34 ml/100 g/min and at 36.9 +/- 0.58 degrees C it was 27.3 +/- 7.40 ml/100 g/min (p = NS). The control patients increased cerebral blood flow from 20.7 +/- 6.78 ml/100 g/min at 28.4 +/- 2.81 degrees C to 37.6 +/- 8.81 ml/100 g/min at 36.5 +/- 0.45 degrees C (p less than or equal to 0.005). The oxygen consumption was calculated from jugular bulb effluent and increased from hypothermic values of 0.52 +/- 0.20 ml/100 g/min in diabetics to 1.26 +/- 0.28 ml/100 g/min (p = 0.001) at normothermia and rose from 0.60 +/- 0.27 to 1.49 +/- 0.35 ml/100 g/min (p = 0.0005) in the controls. Thus, despite temperature-mediated changes in oxygen consumption, diabetic patients did not increase cerebral blood flow as metabolism increased. Arteriovenous oxygen saturation gradients and oxygen extraction across the brain were calculated from arterial and jugular bulb blood samples. The increase in arteriovenous oxygen difference between temperature conditions in diabetic patients and controls was significantly different (p = 0.01). These data reveal that diabetic patients lose cerebral autoregulation during cardiopulmonary bypass and compensate for an imbalance in adequate oxygen delivery by increasing oxygen extraction.

  2. Brain luxury perfusion during cardiopulmonary bypass in humans. A study of the cerebral blood flow response to changes in CO2, O2, and blood pressure.

    PubMed

    Henriksen, L

    1986-06-01

    CBF and related parameters were studied in 68 patients before, during, and following cardiopulmonary bypass. CBF was measured using the intraarterial 133Xe injection method. The extracorporeal circuit was nonpulsatile with a bubble oxygenator administering 3-5% CO2 in the main group of hypercapnic patients (n = 59) and no CO2 in a second group of hypocapnic patients. In the hypercapnic patients, marked changes in CBF occurred during bypass. Evidence was found of a brain luxury perfusion that could not be related to the effect of CO2 per se. Mean CBF was 29 ml/100 g/min just before bypass, 49 ml/100 g/min at steady-state hypothermia (27 degrees C), reached a maximum of 73 ml/100 g/min during the rewarming phase (32 degrees C), fell to 56 ml/100 g/min at steady-state normothermic bypass (37 degrees C), and was 48 ml/100 g/min shortly after bypass was stopped. Addition of CO2 evoked systemic vasodilation with low blood pressure and a rebound hyperemia. The hypocapnic group responded more physiologically to the induced changes in hematocrit (Htc) and temperature, CBF being 25, 23, 25, 34, and 35 ml/100 g/min, respectively, during the five corresponding periods. Carbon dioxide was an important regulator of CBF during all phases of cardiac surgery, the responsiveness of CBF being approximately 4% for each 1-mm Hg change of PaCO2. The level of MABP was important for the CO2 response. At low blood pressure states, the CBF responsiveness to changes in PaCO2 was almost abolished. An optimal level of PaCO2 during hypothermic bypass of approximately 25 mm Hg (at actual temperature) is recommended. A normal autoregulatory response of CBF to changes in blood pressure was found during and following bypass. The lower limit of autoregulation was at pressure levels of approximately 50-60 mm Hg. CBF autoregulation was almost abolished at PaCO2 levels of greater than 50 mm Hg. The degree of hemodilution neither affected the CO2 response nor impaired CBF autoregulation, although, as

  3. Examining Changes in Radioxenon Isotope Activity Ratios during Subsurface Transport

    NASA Astrophysics Data System (ADS)

    Annewandter, Robert

    2014-05-01

    volume method. The parabolic and hyperbolic problem can be solved separately by operator-splitting. The resulting system of linear equations is solved by the algebraic multigrid library SAMG, developed at the Fraunhofer Institute for Algorithms and Scientific Computing, Germany. CSMP++ is developed at Montan University of Leoben, ETH Zuerich, Imperial College London and Heriot-Watt University in Edinburgh. This study examines barometric pumping-driven subsurface transport of Xe-135, Xe-133m, Xe-133, Xe-131m including I-131, I-133 and I-135 on arrival times and isotopic activity ratios. This work was funded by the CTBTO Research Award for Young Scientist and Engineers (2013).

  4. International challenge to predict the impact of radioxenon releases from medical isotope production on a comprehensive nuclear test ban treaty sampling station

    SciTech Connect

    Eslinger, Paul W.; Bowyer, Ted W.; Achim, Pascal; Chai, Tianfeng; Deconninck, Benoit; Freeman, Katie; Generoso, Sylvia; Hayes, Philip; Heidmann, Verena; Hoffman, Ian; Kijima, Yuichi; Krysta, Monika; Malo, Alain; Maurer, Christian; Ngan, Fantine; Robins, Peter; Ross, J. Ole; Saunier, Olivier; Schlosser, Clemens; Schöppner, Michael; Schrom, Brian T.; Seibert, Petra; Stein, Ariel F.; Ungar, Kurt; Yi, Jing

    2016-06-01

    Abstract The International Monitoring System (IMS) is part of the verification regime for the Comprehensive Nuclear-Test-Ban-Treaty Organization (CTBTO). At entry-into-force, half of the 80 radionuclide stations will be able to measure concentrations of several radioactive xenon isotopes produced in nuclear explosions, and then the full network may be populated with xenon monitoring afterward (Bowyer et al., 2013). Fission-based production of 99Mo for medical purposes also releases radioxenon isotopes to the atmosphere (Saey, 2009). One of the ways to mitigate the effect of emissions from medical isotope production is the use of stack monitoring data, if it were available, so that the effect of radioactive xenon emissions could be subtracted from the effect from a presumed nuclear explosion, when detected at an IMS station location. To date, no studies have addressed the impacts the time resolution or data accuracy of stack monitoring data have on predicted concentrations at an IMS station location. Recently, participants from seven nations used atmospheric transport modeling to predict the time-history of 133Xe concentration measurements at an IMS station in Germany using stack monitoring data from a medical isotope production facility in Belgium. Participants received only stack monitoring data and used the atmospheric transport model and meteorological data of their choice. Some of the models predicted the highest measured concentrations quite well (a high composite statistical model comparison rank or a small mean square error with the measured values). The results suggest release data on a 15 min time spacing is best. The model comparison rank and ensemble analysis suggests that combining multiple models may provide more accurate predicted concentrations than any single model. Further research is needed to identify optimal methods for selecting ensemble members and those methods may depend on the specific transport problem. None of the submissions based only

  5. An inverse modeling method to assess the source term of the Fukushima Nuclear Power Plant accident using gamma dose rate observations

    NASA Astrophysics Data System (ADS)

    Saunier, O.; Mathieu, A.; Didier, D.; Tombette, M.; Quélo, D.; Winiarek, V.; Bocquet, M.

    2013-11-01

    The Chernobyl nuclear accident, and more recently the Fukushima accident, highlighted that the largest source of error on consequences assessment is the source term, including the time evolution of the release rate and its distribution between radioisotopes. Inverse modeling methods, which combine environmental measurements and atmospheric dispersion models, have proven efficient in assessing source term due to an accidental situation (Gudiksen, 1989; Krysta and Bocquet, 2007; Stohl et al., 2012a; Winiarek et al., 2012). Most existing approaches are designed to use air sampling measurements (Winiarek et al., 2012) and some of them also use deposition measurements (Stohl et al., 2012a; Winiarek et al., 2014). Some studies have been performed to use dose rate measurements (Duranova et al., 1999; Astrup et al., 2004; Drews et al., 2004; Tsiouri et al., 2012) but none of the developed methods were carried out to assess the complex source term of a real accident situation like the Fukushima accident. However, dose rate measurements are generated by the most widespread measurement system, and in the event of a nuclear accident, these data constitute the main source of measurements of the plume and radioactive fallout during releases. This paper proposes a method to use dose rate measurements as part of an inverse modeling approach to assess source terms. The method is proven efficient and reliable when applied to the accident at the Fukushima Daiichi Nuclear Power Plant (FD-NPP). The emissions for the eight main isotopes 133Xe, 134Cs, 136Cs, 137Cs, 137mBa, 131I, 132I and 132Te have been assessed. Accordingly, 105.9 PBq of 131I, 35.8 PBq of 132I, 15.5 PBq of 137Cs and 12 134 PBq of noble gases were released. The events at FD-NPP (such as venting, explosions, etc.) known to have caused atmospheric releases are well identified in the retrieved source term. The estimated source term is validated by comparing simulations of atmospheric dispersion and deposition with

  6. Interpreting aerosol lifetimes using the GEOS-Chem model and constraints from radionuclide measurements

    NASA Astrophysics Data System (ADS)

    Croft, B.; Pierce, J. R.; Martin, R. V.

    2014-04-01

    Aerosol removal processes control global aerosol abundance, but the rate of that removal remains uncertain. A recent study of aerosol-bound radionuclide measurements after the Fukushima Daiichi nuclear power plant accident documents 137Cs removal (e-folding) times of 10.0-13.9 days, suggesting that mean aerosol lifetimes in the range of 3-7 days in global models might be too short by a factor of two. In this study, we attribute this discrepancy to differences between the e-folding and mean aerosol lifetimes. We implement a simulation of 137Cs and 133Xe into the GEOS-Chem chemical transport model and examine the removal rates for the Fukushima case. We find a general consistency between modelled and measured e-folding times. The simulated 137Cs global burden e-folding time is about 14 days. However, the simulated mean lifetime of aerosol-bound 137Cs over a 6-month post-accident period is only 1.8 days. We find that the mean lifetime depends strongly on the removal rates in the first few days after emissions, before the aerosols leave the boundary layer and are transported to altitudes and latitudes where lifetimes with respect to wet removal are longer by a few orders of magnitude. We present sensitivity simulations that demonstrate the influence of differences in altitude and location of the radionuclides on the mean lifetime. Global mean lifetimes are shown to strongly depend on the altitude of injection. The global mean 137Cs lifetime is more than one order of magnitude greater for the injection at 7 km than into the boundary layer above the Fukushima site. Instantaneous removal rates are slower during the first few days after the emissions for a free tropospheric versus boundary layer injection and this strongly controls the mean lifetimes. Global mean aerosol lifetimes for the GEOS-Chem model are 3-6 days, which is longer than that for the 137Cs injected at the Fukushima site (likely due to precipitation shortly after Fukushima emissions), but similar to the

  7. Variation in airborne 137Cs peak levels with altitude from high-altitude locations across Europe after the arrival of Fukushima-labeled air masses

    NASA Astrophysics Data System (ADS)

    Masson, Olivier; Bieringer, Jacqueline; Dalheimer, Axel; Estier, Sybille; Evrard, Olivier; Penev, Ilia; Ringer, Wolfgang; Schlosser, Clemens; Steinkopff, Thomas; Tositti, Laura; de Vismes-Ott, Anne

    2015-04-01

    level were transported until Europe at rather high altitudes. This is consistent with 137Cs activity levels and 133Xe observations performed at the tropopause level thanks to aircraft samples over Germany and Switzerland (Estier and Steinmann). This also validates dispersion model computation according to which the Fukushima-labeled air masses were transported to Europe above 5500 m a.s.l. Conclusions : High altitude locations are on 'sentry duty' for radioactive monitoring and cross-border spreading of a contaminated plume. In this sense they can provide useful information on the vertical spreading of radionuclides, reveal arrival times over a given region and make it possible to explain ground deposition levels as a result of interactions of cloud droplets or rain drops with aerosols at high altitude. Beside non-homogeneities encountered on the European scale at lowland locations, this study shows that 137Cs peak activity levels regularly decreased between about 3500 m and less than 1000 m a.s.l. In addition field measurements confirm that air masses travelled at high altitude and that the 137Cs peaks were due to air masses coming from high tropospheric levels. This study also highlights the need to reinforce high-altitude aerosol sampling during emergency situations. This will make it possible to specify the dispersion conditions for modeling purposes and help explaining simulation and observation discrepancies.

  8. Evaluation of Observed and Modelled Aerosol Lifetimes Using Radioactive Tracers of Opportunity and an Ensemble of 19 Global Models

    NASA Technical Reports Server (NTRS)

    Kristiansen, N. I.; Stohl, A.; Olivie, D. J. L.; Croft, B.; Sovde, O. A.; Klein, H.; Christoudias, T.; Kunkel, D.; Leadbetter, S. J.; Lee, Y. H.; Zhang, K.; Tsigaridis, K.; Bauer, S. E.; Faluvegi, G. S.; Shindell, D.

    2016-01-01

    Aerosols have important impacts on air quality and climate, but the processes affecting their removal from the atmosphere are not fully understood and are poorly constrained by observations. This makes modelled aerosol lifetimes uncertain. In this study, we make use of an observational constraint on aerosol lifetimes provided by radionuclide measurements and investigate the causes of differences within a set of global models. During the Fukushima Dai-Ichi nuclear power plant accident of March 2011, the radioactive isotopes cesium-137 (Cs-137) and xenon-133 (Xe-133) were released in large quantities. Cesium attached to particles in the ambient air, approximately according to their available aerosol surface area. Cs-137 size distribution measurements taken close to the power plant suggested that accumulation mode (AM) sulfate aerosols were the main carriers of cesium. Hence, Cs-137 can be used as a proxy tracer for the AM sulfate aerosol's fate in the atmosphere. In contrast, the noble gas Xe-133 behaves almost like a passive transport tracer. Global surface measurements of the two radioactive isotopes taken over several months after the release allow the derivation of a lifetime of the carrier aerosol. We compare this to the lifetimes simulated by 19 different atmospheric transport models initialized with identical emissions of Cs-137that were assigned to an aerosol tracer with each model's default properties of AM sulfate, and Xe-133 emissions that were assigned to a passive tracer. We investigate to what extent the modelled sulfate tracer can reproduce the measurements, especially with respect to the observed loss of aerosol mass with time. Modelled Cs-137and Xe-133 concentrations sampled at the same location and times as station measurements allow a direct comparison between measured and modelled aerosol lifetime. The e-folding lifetime e, calculated from station measurement data taken between 2 and 9 weeks after the start of the emissions, is 14.3 days (95

  9. Examining Changes in Radioxenon Isotope Activity Ratios during Subsurface Transport

    NASA Astrophysics Data System (ADS)

    Annewandter, R.

    2013-12-01

    differential equations by a complementary finite volume method. The parabolic and hyperbolic problem can be solved separately using the operator-splitting method (Implicit Pressure Explicit Saturation, IMPES). The resulting system of linear equations is solved by the algebraic multigrid library SAMG, developed at the Fraunhofer Institute for Algorithms and Scientific Computing. CSMP++ is developed at Montan University of Leoben, ETH Zuerich, Imperial College London and Heriot-Watt University in Edinburgh. To date, there has been no research investigating how subsurface transport impacts isotope activity ratios. The isotopic activity ratio method can be used to discriminate between civil release or nuclear explosion sources. This study examines possible fractionation of Xe-135, Xe-133m, Xe-133, Xe-131m during barometric pumping-driven subsurface migration, which can affect surface arrival times and isotopic activity ratios. Surface arrival times for the Noble gases Kr-81, Kr-85 and Ar-39 are also calculated.

  10. Atmospheric lifetime of caesium-137 as an estimate of aerosol lifetime -quantified from global measurements in the months after the Fukushima Dai-ichi nuclear accident

    NASA Astrophysics Data System (ADS)

    Iren Kristiansen, Nina; Stohl, Andreas; Wotawa, Gerhard

    2013-04-01

    Radionuclides like caesium-137 (137Cs) can be emitted to the atmosphere in great quantities during nuclear accidents and are of significant health impact. A global set of radionuclide measurements collected over several months after the accidental release from the Fukushima Dai-ichi nuclear power plant in March 2011 has been used to estimate the atmospheric lifetime of 137Cs. Lifetime is here defined as the e-folding time scale (the time interval in which the exponential decay of the 137Cs quantity has decreased by factor of e). The estimated atmospheric lifetime of 137Cs can also be used as an estimate of the lifetime of aerosols in the atmosphere. This is based on the fact that 137Cs attaches to the ambient accumulation-mode (AM) aerosols and trace their fate in the atmosphere. The 137Cs "tags" the AM aerosols and both the 137Cs and AM aerosols are removed simultaneously from the atmosphere by scavenging within clouds, precipitation and dry deposition. The 137Cs emitted from Fukushima attached mainly to sulphate aerosols in the size range 0.1-2 μm diameter. Measured 137Cs activity concentrations from several stations spread mostly over the Northern Hemisphere were evaluated, and the decrease in activity concentrations over time (after correction for radioactive decay) reflects the removal of aerosols by wet and dry deposition. Corrections for air mass transport were made using measurements of the noble gas xenon-133 (133Xe) which was also released during the accident. This noble gas does not attach to the aerosols and was thus used as a passive tracer of air mass transport. The atmospheric lifetime of 137Cs was estimated to 10.0-13.9 days during April and May 2011. This represents the atmospheric lifetime of a "background" AM aerosol well mixed in the extratropical northern hemisphere troposphere. It is expected that the lifetime of this vertically mixed background aerosol is longer than the lifetime of fresh AM aerosols directly emitted from surface sources