Science.gov

Sample records for acute x-ray exposure

  1. X-ray exposure sensor and controller

    NASA Technical Reports Server (NTRS)

    Berdahl, C. Martin (Inventor)

    1977-01-01

    An exposure controller for x-ray equipment is provided, which comprises a portable and accurate sensor which can be placed adjacent to and directly beneath the area of interest of an x-ray plate, and which measures the amount of exposure received by that area, and turns off the x-ray equipment when the exposure for the particular area of interest on the x-ray plate reaches the value which provides an optimal x-ray plate.

  2. A paediatric X-ray exposure chart

    SciTech Connect

    Knight, Stephen P

    2014-09-15

    The aim of this review was to develop a radiographic optimisation strategy to make use of digital radiography (DR) and needle phosphor computerised radiography (CR) detectors, in order to lower radiation dose and improve image quality for paediatrics. This review was based on evidence-based practice, of which a component was a review of the relevant literature. The resulting exposure chart was developed with two distinct groups of exposure optimisation strategies – body exposures (for head, trunk, humerus, femur) and distal extremity exposures (elbow to finger, knee to toe). Exposure variables manipulated included kilovoltage peak (kVp), target detector exposure and milli-ampere-seconds (mAs), automatic exposure control (AEC), additional beam filtration, and use of antiscatter grid. Mean dose area product (DAP) reductions of up to 83% for anterior–posterior (AP)/posterior–anterior (PA) abdomen projections were recorded postoptimisation due to manipulation of multiple-exposure variables. For body exposures, the target EI and detector exposure, and thus the required mAs were typically 20% less postoptimisation. Image quality for some distal extremity exposures was improved by lowering kVp and increasing mAs around constant entrance skin dose. It is recommended that purchasing digital X-ray equipment with high detective quantum efficiency detectors, and then optimising the exposure chart for use with these detectors is of high importance for sites performing paediatric imaging. Multiple-exposure variables may need to be manipulated to achieve optimal outcomes.

  3. A paediatric X-ray exposure chart.

    PubMed

    Knight, Stephen P

    2014-09-01

    The aim of this review was to develop a radiographic optimisation strategy to make use of digital radiography (DR) and needle phosphor computerised radiography (CR) detectors, in order to lower radiation dose and improve image quality for paediatrics. This review was based on evidence-based practice, of which a component was a review of the relevant literature. The resulting exposure chart was developed with two distinct groups of exposure optimisation strategies - body exposures (for head, trunk, humerus, femur) and distal extremity exposures (elbow to finger, knee to toe). Exposure variables manipulated included kilovoltage peak (kVp), target detector exposure and milli-ampere-seconds (mAs), automatic exposure control (AEC), additional beam filtration, and use of antiscatter grid. Mean dose area product (DAP) reductions of up to 83% for anterior-posterior (AP)/posterior-anterior (PA) abdomen projections were recorded postoptimisation due to manipulation of multiple-exposure variables. For body exposures, the target EI and detector exposure, and thus the required mAs were typically 20% less postoptimisation. Image quality for some distal extremity exposures was improved by lowering kVp and increasing mAs around constant entrance skin dose. It is recommended that purchasing digital X-ray equipment with high detective quantum efficiency detectors, and then optimising the exposure chart for use with these detectors is of high importance for sites performing paediatric imaging. Multiple-exposure variables may need to be manipulated to achieve optimal outcomes.

  4. A paediatric X-ray exposure chart

    PubMed Central

    Knight, Stephen P

    2014-01-01

    The aim of this review was to develop a radiographic optimisation strategy to make use of digital radiography (DR) and needle phosphor computerised radiography (CR) detectors, in order to lower radiation dose and improve image quality for paediatrics. This review was based on evidence-based practice, of which a component was a review of the relevant literature. The resulting exposure chart was developed with two distinct groups of exposure optimisation strategies – body exposures (for head, trunk, humerus, femur) and distal extremity exposures (elbow to finger, knee to toe). Exposure variables manipulated included kilovoltage peak (kVp), target detector exposure and milli-ampere-seconds (mAs), automatic exposure control (AEC), additional beam filtration, and use of antiscatter grid. Mean dose area product (DAP) reductions of up to 83% for anterior–posterior (AP)/posterior–anterior (PA) abdomen projections were recorded postoptimisation due to manipulation of multiple-exposure variables. For body exposures, the target EI and detector exposure, and thus the required mAs were typically 20% less postoptimisation. Image quality for some distal extremity exposures was improved by lowering kVp and increasing mAs around constant entrance skin dose. It is recommended that purchasing digital X-ray equipment with high detective quantum efficiency detectors, and then optimising the exposure chart for use with these detectors is of high importance for sites performing paediatric imaging. Multiple-exposure variables may need to be manipulated to achieve optimal outcomes. PMID:26229655

  5. Improved intensifying screen reduces X-ray exposure

    NASA Technical Reports Server (NTRS)

    Buchanan, R. A.

    1972-01-01

    X-ray intensifying screen may make possible radiographic procedures where detection speed and X-ray tube power have been the limiting factors. Device will reduce total population exposure to harmful radiation in the United States.

  6. Design Criteria for Shipboard Dental Spaces: X-Ray Exposure Rooms; X-Ray Darkrooms; Storerooms.

    DTIC Science & Technology

    shipboard dental spaces: dental X-ray exposure rooms; dental X-ray darkrooms; dental storerooms. These design criteria are intended to assist the Naval Ship...Systems Command in designing and building shipboard dental spaces which will most efficiently and economically accomplish their purposes. They embody

  7. Improved control of medical x-ray film exposure

    NASA Technical Reports Server (NTRS)

    Berdahl, C. M.

    1978-01-01

    Exposure sensing system for light-intensified motion-picture X-ray system uses aperture or adjustable diaphragm to sample light from image region of interest. Approach, along with approximate optics, can optimize exposure sensitivity.

  8. Diagnostic X-ray and ultrasound exposure and risk of childhood cancer.

    PubMed Central

    Shu, X. O.; Jin, F.; Linet, M. S.; Zheng, W.; Clemens, J.; Mills, J.; Gao, Y. T.

    1994-01-01

    In a population-based case-control study of 642 childhood cancer cases and the same number of matched controls in Shanghai, China, we evaluated the relationship between diagnostic X-ray (preconception, pre- and post-natal) and antenatal ultrasound exposure and the subsequent risk of developing three major types of childhood cancer (acute leukaemia, lymphoma and brain tumours) and all childhood neoplasms combined. Consistent with previous studies, prenatal X-ray exposure was found to be associated with an 80% increased risk of childhood cancers, although the estimation was based on 4% and 2% exposed cases and controls and was only marginally statistically significant (P = 0.08). Post-natal X-ray exposure was also linked with a small elevation in the risk of all cancers and the major categories of malignancies in children. Little evidence, however, was found to relate parental preconception X-ray exposure with the subsequent cancer risk in offspring, regardless of the exposure window and the anatomical site of X-ray exposures. This study adds further to the growing literature indicating that antenatal ultrasound exposure is probably not associated with an increased risk of childhood cancer. PMID:8080742

  9. Digital radiography can reduce scoliosis x-ray exposure

    SciTech Connect

    Kling, T.F. Jr.; Cohen, M.J.; Lindseth, R.E.; De Rosa, G.P. )

    1990-09-01

    Digital radiology is a new computerized system of acquiring x-rays in a digital (electronic) format. It possesses a greatly expanded dose response curve that allows a very broad range of x-ray dose to produce a diagnostic image. Potential advantages include significantly reduced radiation exposure without loss of image quality, acquisition of images of constant density irrespective of under or over exposure, and reduced repeat rates for unsatisfactory films. The authors prospectively studied 30 adolescents with scoliosis who had both conventional (full dose) and digital (full, one-half, or one-third dose) x-rays. They found digital made AP and lateral image with all anatomic areas clearly depicted at full and one-half dose. Digital laterals were better at full dose and equal to conventional at one-half dose. Cobb angles were easily measured on all one-third dose AP and on 8 of 10 one-third dose digital laterals. Digital clearly depicted the Risser sign at one-half and one-third dose and the repeat rate was nil in this study, indicating digital compensates well for exposure errors. The study indicates that digital does allow radiation dose to be reduced by at least one-half in scoliosis patients and that it does have improved image quality with good contrast over a wide range of x-ray exposure.

  10. Prenatal x-ray exposure and childhood cancer in twins

    SciTech Connect

    Harvey, E.B.; Boice, J.D. Jr.; Honeyman, M.; Flannery, J.T.

    1985-02-28

    A case-control study was conducted to investigate the relation between prenatal exposure to x-rays and childhood cancer, including leukemia, in over 32,000 twins born in Connecticut from 1930 to 1969. Twins as opposed to single births were chosen for study to reduce the likelihood of medical selection bias, since twins were often exposed to x-rays to diagnose the twin pregnancy or to determine fetal positioning before delivery and not because of medical conditions that may conceivably pre-dispose to cancer. Each of 31 incident cases of cancer, identified by linking the Connecticut twin and tumor registries, was matched with four twin controls according to sex, year of birth, and race. Records of hospitals, radiologists, and private physicians were searched for histories of x-ray exposure and other potentially important risk factors. Documented prenatal x-ray exposures were found for 39 per cent of the cases (12 of 31) and for 26 per cent of the controls (28 of 109). No other pregnancy, delivery, or maternal conditions were associated with cancer risk except low birth weight: 38 per cent of the cases as compared with 25 per cent of the controls weighed under 2.27 kg at birth. When birth weight was adjusted for, twins in whom leukemia or other childhood cancer developed were twice as likely to have been exposed to x-rays in utero as twins who were free of disease (relative risk, 2.4; 95 per cent confidence interval, 1.0 to 5.9). The results, though based on small numbers, provide further evidence that low-dose prenatal irradiation may increase the risk of childhood cancer.

  11. 21 CFR 872.1820 - Dental x-ray exposure alignment device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Dental x-ray exposure alignment device. 872.1820... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.1820 Dental x-ray exposure alignment device. (a) Identification. A dental x-ray exposure alignment device is a device intended to position...

  12. 21 CFR 872.1820 - Dental x-ray exposure alignment device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Dental x-ray exposure alignment device. 872.1820... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.1820 Dental x-ray exposure alignment device. (a) Identification. A dental x-ray exposure alignment device is a device intended to position...

  13. 21 CFR 872.1820 - Dental x-ray exposure alignment device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Dental x-ray exposure alignment device. 872.1820... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.1820 Dental x-ray exposure alignment device. (a) Identification. A dental x-ray exposure alignment device is a device intended to position...

  14. 21 CFR 872.1820 - Dental x-ray exposure alignment device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Dental x-ray exposure alignment device. 872.1820... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.1820 Dental x-ray exposure alignment device. (a) Identification. A dental x-ray exposure alignment device is a device intended to position...

  15. 21 CFR 872.1820 - Dental x-ray exposure alignment device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental x-ray exposure alignment device. 872.1820... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.1820 Dental x-ray exposure alignment device. (a) Identification. A dental x-ray exposure alignment device is a device intended to position x...

  16. Radiation Exposure in X-Ray and CT Examinations

    MedlinePlus

    ... procedures. See the X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety page for more information. top of page ... and Radiation Safety X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Videos related to Radiation Dose in X- ...

  17. Effect of repeated x-ray exposure on the resolution of amorphous selenium based x-ray imagers

    PubMed Central

    Kabir, M. Z.; Chowdhury, L.; DeCrescenzo, G.; Tousignant, O.; Kasap, S. O.; Rowlands, J. A.

    2010-01-01

    Purpose: A numerical model and the experimental methods to study the x-ray exposure dependent change in the modulation transfer function (MTF) of amorphous selenium (a-Se) based active matrix flat panel imagers (AMFPIs) are described. The physical mechanisms responsible for the x-ray exposure dependent change in MTF are also investigated. Methods: A numerical model for describing the x-ray exposure dependent MTF of a-Se based AMFPIs has been developed. The x-ray sensitivity and MTF of an a-Se AMFPI have been measured as a function of exposure. The instantaneous electric field and free and trapped carrier distributions in the photoconductor layer are obtained by numerically solving the Poisson’s equation, continuity equations, and trapping rate equations using the backward Euler finite difference method. From the trapped carrier distributions, a method for calculating the MTF due to incomplete charge collection is proposed. Results: The model developed in this work and the experimental data show a reasonably good agreement. The model is able to simultaneously predict the dependence of the sensitivity and MTF on accumulated exposure at different applied fields and bias polarities, with the same charge transport parameters that are typical of the particular a-Se photoconductive layer that is used in these AMFPIs. Under negative bias, the MTF actually improves with the accumulated x-ray exposure while the sensitivity decreases. The MTF enhancement with exposure decreases with increasing applied field. Conclusions: The most prevalent processes that control the MTF under negative bias are the recombination of drifting holes with previously trapped electrons (electrons remain in deep traps due to their long release times compared with the time scale of the experiments) and the deep trapping of drifting holes and electrons. PMID:20384271

  18. [Assessment of parameters of digital X-ray detectors by the method of exposure of the working area of the detector to uniform X-ray radiation].

    PubMed

    Mazurov, A I

    2007-01-01

    It is shown that the main parameters determining the imaging quality of digital X-ray image detectors can be assessed by the method of exposure of the working area of the detector to uniform X-ray radiation. This method makes unnecessary the expert evaluation and measurements using high-precision test objects. It can be used in clinical practice for effective monitoring of the quality of digital X-ray detectors.

  19. Procedures to minimize diagnostic x-ray exposure of the human embryo and fetus

    SciTech Connect

    Not Available

    1981-08-01

    The recommendations in this publication emphasize the necessity for the attending physicians to determine whether or not their patients might be pregnant and to use this information in deciding on the need for an x-ray examination. The recommendations also stress the need to reduce x-ray exposure throughout gestation, and suggest ways in which this can be done. (KRM)

  20. Imaging local electric fields produced upon synchrotron X-ray exposure

    DOE PAGES

    Dettmar, Christopher M.; Newman, Justin A.; Toth, Scott J.; ...

    2014-12-31

    Electron–hole separation following hard X-ray absorption during diffraction analysis of soft materials under cryogenic conditions produces substantial local electric fields visualizable by second harmonic generation (SHG) microscopy. Monte Carlo simulations of X-ray photoelectron trajectories suggest the formation of substantial local electric fields in the regions adjacent to those exposed to X-rays, indicating a possible electric-field–induced SHG (EFISH) mechanism for generating the observed signal. In studies of amorphous vitreous solvents, analysis of the SHG spatial profiles following X-ray microbeam exposure was consistent with an EFISH mechanism. Within protein crystals, exposure to 12-keV (1.033-Å) X-rays resulted in increased SHG in the regionmore » extending ~3 μm beyond the borders of the X-ray beam. Moderate X-ray exposures typical of those used for crystal centering by raster scanning through an X-ray beam were sufficient to produce static electric fields easily detectable by SHG. The X-ray–induced SHG activity was observed with no measurable loss for longer than 2 wk while maintained under cryogenic conditions, but disappeared if annealed to room temperature for a few seconds. In conclusion, these results provide direct experimental observables capable of validating simulations of X-ray–induced damage within soft materials. Additionally, X-ray–induced local fields may potentially impact diffraction resolution through localized piezoelectric distortions of the lattice.« less

  1. Effect of Multi-Shot X-Ray Exposures in IFE Armor Materials

    SciTech Connect

    Latkowski, J F; Abbott, R P; Schmitt, R C; Bell, B K

    2004-12-10

    As part of the High Average Power Laser (HAPL) program the performance of tungsten as an armor material is being studied. While the armor would be exposed to neutrons, x-rays and ions within an inertial fusion energy (IFE) power plant, the thermomechanical effects are believed to dominate. Using a pulsed x-ray source, long-term exposures of tungsten have been completed at fluences that are of interest for the IFE application. Modeling is used in conjunction with experiments on the XAPPER x-ray damage facility in an effort to recreate the effects that would be expected in an operating IFE power plant. X-ray exposures have been completed for a variety of x-ray fluences and number of shots. Analysis of the samples suggests that surface roughening has a threshold that is very close to the fluences that reproduce the peak temperatures expected in an IFE armor material.

  2. Influence of exposure time on the sensitivity of kodak 101 x-ray film.

    PubMed

    Nishimura, H; Eidmann, K; Sugimoto, K; Schwanda, W; Toyoda, T; Taniguchi, K; Kato, Y; Nakai, S

    1991-01-01

    The sensitivity of Kodak 101-07 film to 1-keV x-ray photons was measured at extremely different dose rates by using two sources: a laser-produced plasma with nanosecond emission and a CW x-ray source. Whereas almost equal sensitivities were obtained at lower exposures, the γ values and the saturation densities at higher exposures differed in the two cases, showing the existence of reciprocity failure.

  3. Time and exposure dependent x-ray sensitivity in multilayer amorphous selenium detectors

    NASA Astrophysics Data System (ADS)

    Manouchehri, F.; Kabir, M. Z.; Tousignant, O.; Mani, H.; Devabhaktuni, V. K.

    2008-12-01

    A numerical model is developed to study the time and exposure dependent x-ray sensitivity of multilayer a-Se x-ray imaging detectors on repeated x-ray exposures by considering accumulated trapped charges and their effects (trap filling, recombination, electric field profile, electric field dependent electron-hole pair creation), the carrier transport in the blocking layers, x-ray induced metastable deep trap centre generations and the effects of charge injection. The time-dependent carrier detrapping and structural relaxation (recovery of metastable trap centres) are also considered. The continuity equations for both holes and electrons, trapping rate equations, and Poisson's equation across the photoconductor for a step x-ray exposure are simultaneously solved by the backward Euler finite difference method. The electric field distribution across the multilayer detector and the dark current density under repeated exposures are also estimated. The sensitivity in a rested sample is recovered mainly by the carrier detrapping and the recombination of the injected carriers with the existing trapped carriers. The sensitivity is expected to recover almost fully by resting the sample longer than the recovery time constant of the metastable trap centres (the structural relaxation time constant), which is in the range of several hours. The simulation result is fitted with the experimental data. The proposed theoretical model shows very good agreement with the experimental relative sensitivity versus time and accumulative x-ray exposure characteristics.

  4. Video x-ray progressive scanning: new technique for decreasing x-ray exposure without decreasing image quality during cardiac catheterization

    SciTech Connect

    Holmes, D.R. Jr.; Bove, A.A.; Wondrow, M.A.; Gray, J.E.

    1986-05-01

    A newly developed video x-ray progressive scanning system improves image quality, decreases radiation exposure, and can be added to any pulsed fluoroscopic x-ray system using a video display without major system modifications. With use of progressive video scanning, the radiation entrance exposure rate measured with a vascular phantom was decreased by 32 to 53% in comparison with a conventional fluoroscopic x-ray system. In addition to this substantial decrease in radiation exposure, the quality of the image was improved because of less motion blur and artifact. Progressive video scanning has the potential for widespread application to all pulsed fluoroscopic x-ray systems. Use of this technique should make cardiac catheterization procedures and all other fluoroscopic procedures safer for the patient and the involved medical and paramedical staff.

  5. Dental diagnostic X-ray exposure and risk of benign and malignant brain tumors.

    PubMed

    Lin, M C; Lee, C F; Lin, C L; Wu, Y C; Wang, H E; Chen, C L; Sung, F C; Kao, C H

    2013-06-01

    This study evaluates the risk of benign brain tumors (BBTs) and malignant brain tumors (MBTs) associated with dental diagnostic X-ray, using a large population-based case-control study. We identified 4123 BBT cases and 16 492 controls without BBT (study 1) and 197 MBT cases and 788 controls without MBT (study 2) from Taiwan National Health Insurance claim data. The risks of both types of tumor were estimated in association with the frequency of received dental diagnostic X-ray. The mean ages were ~44.2 years in study 1 and 40.6 years in study 2. Multivariable unconditional logistic regression analysis showed that the risk of BBT increases as the frequency of received dental diagnostic X-ray increases. The BBT odds ratio increased from 1.33 [95% confidence interval (CI) 1.22-1.44] for those with annual mean X-ray examination of less than one to 1.65 (95% CI 1.37-1.98) for those with three or more X-ray examinations, after controlling for comorbidities. No significant association was found between MBTs and dental diagnostic X-ray exposure. Exposure to dental diagnostic X-rays in oral and maxillofacial care increases the risk of BBTs, but not MBTs.

  6. Pulsed X-Ray Exposures and Modeling for Tungsten as an IFE First Wall Material

    SciTech Connect

    Latkowski, J F; Abbott, R P; Schmitt, R C

    2004-09-21

    Dry-wall inertial fusion energy (IFE) power plants must survive repeated exposure to target threats that include x-rays, ions, and neutrons. While this exposure may lead to sputtering, exfoliation, transmutation, and swelling, more basic effects are thermomechanical in nature. In the present work, we use the newly developed RadHeat code to predict time-temperature profiles in a tungsten armor, which has been proposed for use in an IFE power plant. The XAPPER x-ray damage experiment is used to simulate thermal effects by operating at fluences that produce similar peak temperatures, temperature gradients, or thermomechanical stresses. Soft x-ray fluences in excess of 1 J/cm{sup 2} are possible. Using RadHeat, we determine the XAPPER x-ray fluence needed to simulate thermomechanical effects expected in a typical IFE case of interest. Here, we report our findings and detail directions for future experiments and modeling.

  7. Procedures to minimize diagnostic x-ray exposure of the human embryo and fetus. Final report

    SciTech Connect

    Not Available

    1980-08-01

    The recommendations published here are intended for the attending physician, the radiologist, the technologist, and the patient, delineating their respective roles in optimizing the x-ray exposure of pregnant or potentially pregnant women. These recommendations emphasize the necessity for attending physicians to determine whether or not their patients might be pregnant and to use this information in deciding on the need for an x-ray examination. The recommendations also stress the need to reduce x-ray exposure throughout gestation, and suggest ways in which this can be accomplished. X-ray exposure of the developing embryo and fetus has been a matter of concern for many years. Several national and international organizations have developed guidelines or policy statements on the subject. The BRH recommendations are expansions of the conceptual foundations provided by these other organizations, and they clarify the ways in which medical radiation exposure can be minimized without compromising the medical care of the mother. These recommendations are based on the principle that unnecessary or unproductive medical radiation exposure should be avoided or reduced to the extent possible, while preserving and improving the anticipated benefits of radiological diagnostic information. As with all medical applications of ionizing radiation, the physician's decision to obtain a diagnostic x-ray examination of a pregnant or potentially pregnant patient should be based on the judgment that the medical information obtained is likely to be important for appropriate patient management.

  8. Diagnostic x-ray exposure and lens opacities: the Beaver Dam Eye Study.

    PubMed Central

    Klein, B E; Klein, R; Linton, K L; Franke, T

    1993-01-01

    The Beaver Dam Eye Study is a population-based study of common age-related eye diseases. During the standardized medical history, the 4926 subjects were asked whether they had ever had a chest x-ray, computerized axial tomography (CAT) scan of the head, other x-rays of the head, x-rays of the abdomen, or other diagnostic x-rays. The eye examination included photographs of the lenses of the eyes, which were subsequently graded according to protocol. Nuclear sclerosis and posterior subcapsular opacity were significantly associated with CAT scans. If these relationships are causal, it would highlight the importance of minimizing such exposure to the lens of the eye. PMID:8460743

  9. Computer program for diagnostic X-ray exposure conversion.

    PubMed

    Lewis, S

    1984-01-01

    Presented is a computer program designed to convert any given set of exposure factors sequentially into another, yielding either an equivalent photographic density or one increased or decreased by a specifiable proportion. In addition to containing the wherewithal with which to manipulate a set of exposure factors, the facility to print hard (paper) copy is included enabling the results to be pasted into a notebook and used at any time. This program was originally written as an investigative exercise into examining the potential use of computers for practical radiographic purposes as conventionally encountered. At the same time, its possible use as an educational tool was borne in mind. To these ends, the current version of this program may be used as a means whereby exposure factors used in a diagnostic department may be altered to suit a particular requirement or may be used in the school as a mathematical model to describe the behaviour of exposure factors under manipulation without patient exposure.

  10. Radiation Exposure in X-Ray and CT Examinations

    MedlinePlus

    ... the largest source of background radiation comes from radon gas in our homes (about 2 mSv per ... Like other sources of background radiation, exposure to radon varies widely from one part of the country ...

  11. Effects of embryonic and fetal exposure to x-ray, microwaves, and ultrasound

    SciTech Connect

    Brent, R.L.

    1986-09-01

    Many professionals are unfamiliar with radiation biology or the quantitative nature of the risks. Frequently, microwave, ultrasound, and ionizing radiation risks are confused. Although it is impossible to prove no risk for any environmental hazard, it appears that exposure to microwave radiation below the maximal permissible levels present no measurable risk to the embryo. Ultrasound exposure from diagnostic ultrasonographic imaging equipment also is quite innocuous. It is true that continued surveillance and research into potential risks of these low-level exposures should continue, but at present ultrasound not only improves obstetric care but also reduces the necessity of diagnostic x-ray procedures. In the field of ionizing radiation, we have as good a comprehension of the biologic effects and the quantitative maximum risks as of any other environmental hazard. Although the animal and human data support the conclusion that no increases in the incidence of gross congenital malformations, intrauterine growth retardation, or abortion will occur with exposures less than 5 rad, that does not mean that there are definitely no risks to the embryo exposed to lower doses of radiation. Whether there exists a linear or exponential dose-response relationship or a threshold exposure for genetic, carcinogenic, cell-depleting, and life-shortening effects has not been determined. In establishing maximum permissible levels for the embryo at low exposures, refer to Tables 4, 5, 6, 8, and 9. It is obvious that the risks of 1-rad or 5-rad acute exposure are far below the spontaneous risks of the developing embryo because 15 per cent of human embryos abort, 2.7 to 3.0 per cent of human embryos have major malformations, 4 per cent have intrauterine growth retardation, and 8 to 10 per cent have early- or late-onset genetic disease. 98 references.

  12. [The antioxidant enzyme activity in mouse liver mitochondria after nanosecond pulsed periodic X-ray exposure].

    PubMed

    Kniazeva, I R; Ivanov, V V; Bol'shakov, M A; Zharkova, L P; Kereia, A V; Kutenkov, O P; Rostov, V V

    2013-01-01

    The effect of repetitive pulsed X-ray (4 ns pulse duration, 300 kV accelerating voltage; 2.5 kA electron beam current) on the antioxidant enzyme activity in mouse liver mitochondria has been investigated. The mitochondrial suspension was exposed to single 4000 pulse X-ray radiation with repetition rates ranging between 10 and 22 pps (pulsed dose was 0.3-1.8 x 10(-6) Gy/pulse, the total absorbed dose following a single exposure was 7.2 x 10(-3) Gy). It was shown that a short-time exposure to X-ray radiation changes the antioxidant enzyme activity in mouse liver mitochondria. The greatest effect was observed in the changes of the activity of the metal-containing enzymes: superoxide dismutase and glutathione peroxidase. The effect depends on the pulse repetition frequency and radiation dose.

  13. Handheld X-ray Fluorescence Spectrometers: Radiation Exposure Risks of Matrix-Specific Measurement Scenarios.

    PubMed

    Rouillon, Marek; Kristensen, Louise J; Gore, Damian B

    2015-07-01

    This study investigates X-ray intensity and dispersion around handheld X-ray fluorescence (XRF) instruments during the measurement of a range of sample matrices to establish radiation exposure risk during operation. Four handheld XRF instruments representing three manufacturers were used on four smooth, flat-lying materials of contrasting matrix composition. Dose rates were measured at 10, 20, 30, and 40 cm intervals every 30° around the instrument at 0 and 45° from the horizontal, as well as vertically from the instrument screen. The analysis of polyethylene recorded dose rates 156 times higher (on average) than steel measurements and 34 times higher than both quartz sand and quartz sandstone. A worst-case exposure scenario was assumed where a user analyses a polyethylene material at arms reach for 1 h each working day for one year. This scenario resulted in an effective body dose of 73.5 μSv, equivalent to three to four chest X-rays (20 μSv) a year, 20 times lower than the average annual background radiation exposure in Australia and well below the annual exposure limit of 1 mSv for non-radiation workers. This study finds the advantages of using handheld XRF spectrometers far outweighs the risk of low radiation exposure linked to X-ray scattering from samples.

  14. Medical x-ray exposure doses as contaminants of atomic bomb doses

    SciTech Connect

    Yamamoto, O.; Antoku, S.; Russell, W.J.; Fujita, S.; Sawada, S.

    1988-03-01

    Since 1967 at the times of their biennial ABCC/RERF radiological examinations, all Adult Health Study (AHS) subjects have been interviewed to determine the exposures to medical x-rays they experienced in institutions other than RERF in order to estimate the numbers of examinations and corresponding doses which they received. These data have been stored on computer tapes together with the doses these subjects received during their radiological examinations in the ABCC/RERF Department of Radiology. Thus, their medical x-ray doses are available along with their atomic bomb doses (tentative 1965 doses revised, T65DR) for assessment of the role of ionizing radiation in the development of diseases. The medical x-ray doses incurred at RERF were assessed by means of phantom dosimetry. Those at other institutions were determined using phantom dosimetry data and results of surveys for trends in radiological examinations in Hiroshima and Nagasaki. By the end of 1982, the average medical x-ray doses to the active bone marrow were 12.04 mGy for A-bomb exposed groups and 8.92 mGy for control groups (not-in-cities); to the male gonads, 2.26 mGy and 1.89 mGy, respectively; and to the female gonads, 17.45 mGy and 12.58 mGy, respectively. Results for Hiroshima and Nagasaki were similar. The main impact of medical x-ray doses was in the lowest T65DR group. Medical x-ray active bone marrow doses ranged from 0.05-500% (mean, 35%) of A-bomb doses in the 10-99 mGy T65DR group. In the 100-999 mGy T65DR group, medical x-ray active bone marrow doses ranged from 0.005-50% (mean, 5%) of their T65DR. In the greater than 1000-mGy T65DR group, medical x-ray exposures were proportionally less. Medical x-ray exposures produced smaller doses to the gonads of males than to those of the females.

  15. Dose, exposure time, and resolution in Serial X-ray Crystallography

    SciTech Connect

    Starodub, D; Rez, P; Hembree, G; Howells, M; Shapiro, D; Chapman, H N; Fromme, P; Schmidt, K; Weierstall, U; Doak, R B; Spence, J C

    2007-03-22

    Using detailed simulation and analytical models, the exposure time is estimated for serial crystallography, where hydrated laser-aligned proteins are sprayed across a continuous synchrotron beam. The resolution of X-ray diffraction microscopy is limited by the maximum dose that can be delivered prior to sample damage. In the proposed Serial Crystallography method, the damage problem is addressed by distributing the total dose over many identical hydrated macromolecules running continuously in a single-file train across a continuous X-ray beam, and resolution is then limited only by the available fluxes of molecules and X-rays. Orientation of the diffracting molecules is achieved by laser alignment. We evaluate the incident X-ray fluence (energy/area) required to obtain a given resolution from (1) an analytical model, giving the count rate at the maximum scattering angle for a model protein, (2) explicit simulation of diffraction patterns for a GroEL-GroES protein complex, and (3) the frequency cut off of the transfer function following iterative solution of the phase problem, and reconstruction of a density map in the projection approximation. These calculations include counting shot noise and multiple starts of the phasing algorithm. The results indicate the number of proteins needed within the beam at any instant for a given resolution and X-ray flux. We confirm an inverse fourth power dependence of exposure time on resolution, with important implications for all coherent X-ray imaging. We find that multiple single-file protein beams will be needed for sub-nanometer resolution on current third generation synchrotrons, but not on fourth generation designs, where reconstruction of secondary protein structure at a resolution of 7 {angstrom} should be possible with short (below 100 s) exposures.

  16. Analysis of Patients' X-ray Exposure in 146 Percutaneous Radiologic Gastrostomies.

    PubMed

    Petersen, Tim-Ole; Reinhardt, Martin; Fuchs, Jochen; Gosch, Dieter; Surov, Alexey; Stumpp, Patrick; Kahn, Thomas; Moche, Michael

    2017-09-01

    Purpose Analysis of patient´s X-ray exposure during percutaneous radiologic gastrostomies (PRG) in a larger population. Materials and Methods Data of primary successful PRG-procedures, performed between 2004 and 2015 in 146 patients, were analyzed regarding the exposition to X-ray. Dose-area-product (DAP), dose-length-product (DLP) respectively, and fluoroscopy time (FT) were correlated with the used x-ray systems (Flatpanel Detector (FD) vs. Image Itensifier (BV)) and the necessity for periprocedural placement of a nasogastric tube. Additionally, the effective X-ray dose for PRG placement using fluoroscopy (DL), computed tomography (CT), and cone beam CT (CBCT) was estimated using a conversion factor. Results The median DFP of PRG-placements under fluoroscopy was 163 cGy*cm(2) (flat panel detector systems: 155 cGy*cm(2); X-ray image intensifier: 175 cGy*cm(2)). The median DLZ was 2.2 min. Intraprocedural placement of a naso- or orogastric probe (n = 68) resulted in a significant prolongation of the median DLZ to 2.5 min versus 2 min in patients with an already existing probe. In addition, dose values were analyzed in smaller samples of patients in which the PRG was placed under CBCT (n = 7, median DFP = 2635 cGy*cm(2)), or using CT (n = 4, median DLP = 657 mGy*cm). Estimates of the median DFP and DLP showed effective doses of 0.3 mSv for DL-assisted placements (flat panel detector 0.3 mSv, X-ray image converter 0.4 mSv), 7.9 mSv using a CBCT - flat detector, and 9.9 mSv using CT. This corresponds to a factor 26 of DL versus CBCT, or a factor 33 of DL versus CT. Conclusion In order to minimize X-ray exposure during PRG-procedures for patients and staff, fluoroscopically-guided interventions should employ flat detector systems with short transmittance sequences in low dose mode and with slow image frequency. Series recordings can be dispensed with. The intraprocedural placement of a naso- or orogastric probe

  17. Evaluation of the medical exposure doses regarding dental examinations with different X-ray instruments

    NASA Astrophysics Data System (ADS)

    Liu, Yi-Chi; Chuang, Keh-Shih; Yu, Cheng-Ching; Chao, Jiunn-Hsing; Hsu, Fang-Yuh

    2015-11-01

    Modern dental X-ray examination that consists of traditional form, panorama, and cone-beamed 3D technologies is one of the most frequent diagnostic applications nowadays. This study used the Rando Phantom and thermoluminescence dosimeters (TLD) to measure the absorbed doses of radiosensitive organs recommended by International Commission on Radiological Protection (ICRP), and whole body effective doses which were delivered due to dental X-ray examination performed with different types of X-ray instrument. Besides, enamel samples which performed reading with Electronic Paramagnetic Resonance (EPR) procedure were also used to estimate the tooth doses. EPR is a dose reconstruction method of measuring free radicals induced by radiation exposure to the calcified tissue (mainly in the tooth enamel or bone) to evaluate the accepted high dose. The tooth doses estimated by TLD and EPR methods were compared. Relationships between the tooth doses and effective doses by dental X-ray examinations with different types of X-ray equipment were investigated in this work.

  18. Effect of x-ray exposure (mAs) on peroxide and acid values of honey.

    PubMed

    Inyang, S O; Egbe, N O; Inyang, I S; Azogor, W E; Ekpo, E; Eduwem, D U

    2014-01-01

    Honey is used in most places as food sweetener and antibacterial agent for wounds. The antibacterial property of honey depends mainly on its peroxide value and acidity. This study investigated the possible effect that may be observed on the peroxide value and acidity if honey is exposed to x-ray at varying tube current values (mAs) in order to infer the possible implications of referring patients undergoing honey therapy for diagnostic x-ray examination. The acid and peroxide values were found to vary with changes in the exposure (mAs) value. It is therefore recommended that patients undergoing honey therapy should be referred for diagnostic x-ray examination with caution while radiotherapy should be avoided.

  19. Evaluation of Exposure From a Low Energy X-Ray Device Using Thermoluminescent Dosimeters

    NASA Technical Reports Server (NTRS)

    Edwards, David L.; Harris, William S., Jr.

    1997-01-01

    The exposure from an electron beam welding device was evaluated using thermoluminescent dosimeters (TLDs). The device generated low energy X-rays which the current dose equivalent conversion algorithm was not designed to evaluate making it necessary to obtain additional information relating to TLD operation at the photon energies encountered with the device. This was accomplished by performing irradiations at the National Institute of Standards and Technology (NIST) using low energy X-ray techniques. The resulting data was used to determine TLD badge response for low energy X-rays and to establish the relationship between TLD element response and the dose equivalent at specific depths in tissue for these photon energies. The new energy/dose equivalent calibration data was used to calculate the shallow and eye dose equivalent of badges exposed to the device.

  20. Update of diagnostic medical and dental x-ray exposures in Romania.

    PubMed

    Sorop, Ioana; Mossang, Daniela; Iacob, Mihai Radu; Dadulescu, Elena; Iacob, Olga

    2008-12-01

    This national study, the third in the last 15 years, updates the magnitude of medical radiation exposure from conventional x-ray examinations, in order to optimise the radiological protection to the population in a cost-effective manner. Effective doses from diagnostic radiology were estimated for adult and paediatric patients undergoing the 20 most important types of x-ray examination. Data were collected from 179 x-ray departments, selected by their annual workload, throughout the country. Estimates were made using two dosimetric quantities: entrance surface dose, derived from the absorbed dose in air measured by simulation of radiographic examinations, and dose-area product, measured during fluoroscopic examinations performed on adult and paediatric patients. Conversion coefficients to effective dose of the UK National Radiological Protection Board (NRPB) have been used in all calculations. The effective dose per patient from all medical x-ray examinations was 0.74 mSv and the resulting annual collective effective dose was 6930 man Sv, with annual effective dose per caput of 0.33 mSv. The current size of population exposure from diagnostic radiology is lower than the previous one by 40%, but could be about 30% higher by taking into account the estimated contribution from computed tomography (CT) procedures.

  1. Investigation of Deuterium Loaded Materials Subject to X-Ray Exposure

    NASA Technical Reports Server (NTRS)

    Benyo, Theresa L.; Steinetz, Bruce M.; Hendricks, Robert C.; Martin, Richard E.; Forsley, Lawrence P.; Daniels, Christopher C.; Chait, Arnon; Pines, Vladimir; Pines, Marianna; Penney, Nicholas; Kamm, Tracy R.; Becks, Michael D.

    2017-01-01

    Results are presented from an exploratory study involving x-ray irradiation of select deuterated materials. Titanium deuteride plus deuterated polyethylene, deuterated polyethylene alone, and for control, hydrogen-based polyethylene samples and nondeuterated titanium samples were exposed to x-ray irradiation. These samples were exposed to various energy levels from 65 to 280 kV with prescribed electron flux from 500 to 9000 µA impinging on a tungsten braking target, with total exposure times ranging from 55 to 280 min. Gamma activity was measured using a high-purity germanium (HPGe) detector, and for all samples no gamma activity above background was detected. Alpha and beta activities were measured using a gas proportional counter, and for select samples beta activity was measured with a liquid scintillator spectrometer. The majority of the deuterated materials subjected to the microfocus x-ray irradiation exhibited postexposure beta activity above background and several showed short-lived alpha activity. The HPE and nondeuterated titanium control samples exposed to the x-ray irradiation showed no postexposure alpha or beta activities above background. Several of the samples (SL10A, SL16, SL17A) showed beta activity above background with a greater than 4s confidence level, months after exposure. Portions of SL10A, SL16, and SL17A samples were also scanned using a beta scintillator and found to have beta activity in the tritium energy band, continuing without noticeable decay for over 12 months. Beta scintillation investigation of as-received materials (before x-ray exposure) showed no beta activity in the tritium energy band, indicating the beta emitters were not in the starting materials.

  2. The 172 ks Chandra Exposure of the LALA Bootes Field: X-Ray Source Catalog

    NASA Astrophysics Data System (ADS)

    Wang, J. X.; Malhotra, S.; Rhoads, J. E.; Brown, M. J. I.; Dey, A.; Heckman, T. M.; Jannuzi, B. T.; Norman, C. A.; Tiede, G. P.; Tozzi, P.

    2004-01-01

    We present an analysis of a deep, 172 ks Chandra observation of the Large Area Lyman Alpha survey (LALA) Bootes field, obtained with the Advanced CCD Imaging Spectrometer (ACIS-I) on board the Chandra X-Ray Observatory. This is one of the deepest Chandra images of the extragalactic sky; only the 2 Ms Chandra Deep Field North (CDF-N) and 1 Ms Chandra Deep Field South (CDF-S) are substantially deeper. In this paper we present the X-ray source catalog obtained from this image, along with an analysis of source counts and optical identifications. The X-ray image is composed of two individual observations obtained in 2002 and reaches 0.5-2.0 and 2.0-10.0 keV flux limits of 1.5×10-16 and 1.0×10-15 ergs cm-2 s-1, respectively, for point sources near the aim point. A total of 168 X-ray sources were detected: 160 in the 0.5-7.0 keV band, 132 in the 0.5-2.0 keV band, and 111 in the 2.0-7.0 keV band. The X-ray source counts were derived and compared with those from other Chandra deep surveys; the hard X-ray source density of the LALA Bootes field is 33% higher than that of CDF-S at the flux level of 2.0×10-15 ergs cm-2 s-1, confirming the field-to-field variances of the hard-band source counts reported by previous studies. The deep exposure resolves >~72% of the 2.0-10.0 keV X-ray background. Our primary optical data are R-band imaging from the NOAO Deep Wide-Field Survey (NDWFS), with a limiting magnitude of R=25.7 (Vega, 3 σ, and 4" diameter aperture). We have found optical counterparts for 152 of the 168 Chandra sources (90%); 144 of these are detected in the R-band image, and eight have optical counterparts in other bands (either BW, V, I, or z'). Among the R-band nondetected sources, not more than 11 of them can possibly be at z>5, based on the hardness ratios of their X-ray emission and nondetections in bluer bands (BW, V). The majority (~76%) of the X-ray sources are found to have log(fX/fR) within 0.0+/-1 these are believed to be AGNs. Most of the X-ray

  3. Method for minimizing the radiation exposure from scoliosis radiographs. [X ray

    SciTech Connect

    De Smet, A.A.; Fritz, S.L.; Asher, M.A.

    1981-01-01

    The radiation exposure resulting from standard scoliosis radiographs was determined for eighteen adolescent girls. The risk of inducing breast cancer was estimated from the skin-exposure doses. The average skin exposure to the breasts was 59.6 millirads (0.59 mGy) for the anteroposterior radiograph. Assuming a total of twenty-two anteroposterior radiographs during a course of treatment, the cumulative exposure would result in a 1.35% relative increase in the risk of development of breast cancer. By utilizing collimation of the x-ray beam and proper selection of grids, films, and screens, the radiation risk of scoliosis radiographs is minimized.

  4. SOSORT 2012 consensus paper: reducing x-ray exposure in pediatric patients with scoliosis

    PubMed Central

    2014-01-01

    This 2012 Consensus paper reviews the literature on side effects of x-ray exposure in the pediatric population as it relates to scoliosis evaluation and treatment. Alternative methods of spinal assessment and imaging are reviewed, and strategies for reducing the number of radiographs are developed. Using the Delphi technique, SOSORT members developed consensus statements that describe how often radiographs should be taken in each of the pediatric and adolescent sub-populations. PMID:24782912

  5. Hygiene implications associated with x-ray exposures to dental patients

    SciTech Connect

    McKlveen, J.W.

    1980-12-01

    An elastic mask worn by patients, then a skeleton encased in plastic, was instrumented with LiF thermoluminescent dosimeters to quantify radiation exposures delivered from full-face diagnostic dental x-rays. Locations of interest included skin surface, eyes, upper and lower teeth and thyroid. Exposures in the 100 mR range were common and a maximum of over 6000 mR was measured in the teeth region during a full-face examination with a periapical unit. In general, exposures received from periapical equipment were several times those obtained from panoramic devices.

  6. Uncertainties of exposure-related quantities in mammographic x-ray unit quality control.

    PubMed

    Gregory, Kent J; Pattison, John E; Bibbo, Giovanni

    2006-03-01

    Breast screening programs operate in many countries with mammographic x-ray units subject to stringent quality control tests. These tests include the evaluation of quantities based on exposure measurements, such as half value layer, automatic exposure control reproducibility, average glandular dose, and radiation output rate. There are numerous error sources that contribute to the uncertainty of these exposure-related quantities, some of which are unique to the low energy x-ray spectrum produced by mammographic x-ray units. For each of these exposure-related quantities, the applicable error sources and their magnitudes vary, depending on the test equipment used to make the measurement, and whether or not relevant corrections have been applied. This study has identified and quantified a range of error sources that may be used to estimate the combined uncertainty of these exposure-related quantities, given the test equipment used and corrections applied. The uncertainty analysis uses methods described by the International Standards Organization's Guide to the Expression of Uncertainty in Measurement. Examples of how these error sources combine to give the uncertainty of the exposure-related quantities are presented. Using the best test equipment evaluated in this study, uncertainties of the four exposure-related quantities at the 95% confidence interval were found to be +/-1.6% (half value layer), +/-0.0008 (automatic exposure control reproducibility), +/-2.3% (average glandular dose), and +/-2.1% (radiation output rate). In some cases, using less precise test equipment or failing to apply corrections, resulted in uncertainties more than double in magnitude.

  7. A test cassette for x-ray-exposure experiments at the National Ignition Facility

    SciTech Connect

    Fournier, K. B.; Celeste, J.; Rekow, V.; Bopp, D. R.; May, M. J.; Fisher, J. H.; Horton, R.; Newlander, C. D.; Jenkins, P.; Trautz, K.

    2010-07-01

    We present the design and operation of a test cassette for exposure of samples to radiation environments at the National Ignition Facility. The cassette provides options for square and round samples and exposure areas; the cassette provides for multiple levels of filtration on a single sample, which allows dynamic range in experiments. The samples had normal lines of sight to the x-ray source in order to have uniform x-ray illumination. The incident x-radiation onto the samples was determined by the choice of filter thicknesses and materials. The samples were held at precise locations, accurate to within a few hundred microns, in the target chamber in order to have a known fluence incident. In the cassette, the samples were held in place in such a way that a minimal “line contact” allows them to have the maximal mechanical response to the x-ray load. We present postshot images of the debris found on films used for filters, and pre- and postexposure specimens.

  8. Dual-exposure technique for extending the dynamic range of x-ray flat panel detectors.

    PubMed

    Sisniega, A; Abella, M; Desco, M; Vaquero, J J

    2014-01-20

    This work presents an approach to extend the dynamic range of x-ray flat panel detectors by combining two acquisitions of the same sample taken with two different x-ray photon flux levels and the same beam spectral configuration. In order to combine both datasets, the response of detector pixels was modelled in terms of mean and variance using a linear model. The model was extended to take into account the effect of pixel saturation. We estimated a joint probability density function (j-pdf) of the pixel values by assuming that each dataset follows an independent Gaussian distribution. This j-pdf was used for estimating the final pixel value of the high-dynamic-range dataset using a maximum likelihood method. The suitability of the pixel model for the representation of the detector signal was assessed using experimental data from a small-animal cone-beam micro-CT scanner equipped with a flat panel detector. The potential extension in dynamic range offered by our method was investigated for generic flat panel detectors using analytical expressions and simulations. The performance of the proposed dual-exposure approach in realistic imaging environments was compared with that of a regular single-exposure technique using experimental data from two different phantoms. Image quality was assessed in terms of signal-to-noise ratio, contrast, and analysis of profiles drawn on the images. The dynamic range, measured as the ratio between the exposure for saturation and the exposure equivalent to instrumentation noise, was increased from 76.9 to 166.7 when using our method. Dual-exposure results showed higher contrast-to-noise ratio and contrast resolution than the single-exposure acquisitions for the same x-ray dose. In addition, image artifacts were reduced in the combined dataset. This technique to extend the dynamic range of the detector without increasing the dose is particularly suited to image samples that contain both low and high attenuation regions.

  9. Dual-exposure technique for extending the dynamic range of x-ray flat panel detectors

    NASA Astrophysics Data System (ADS)

    Sisniega, A.; Abella, M.; Desco, M.; Vaquero, J. J.

    2014-01-01

    This work presents an approach to extend the dynamic range of x-ray flat panel detectors by combining two acquisitions of the same sample taken with two different x-ray photon flux levels and the same beam spectral configuration. In order to combine both datasets, the response of detector pixels was modelled in terms of mean and variance using a linear model. The model was extended to take into account the effect of pixel saturation. We estimated a joint probability density function (j-pdf) of the pixel values by assuming that each dataset follows an independent Gaussian distribution. This j-pdf was used for estimating the final pixel value of the high-dynamic-range dataset using a maximum likelihood method. The suitability of the pixel model for the representation of the detector signal was assessed using experimental data from a small-animal cone-beam micro-CT scanner equipped with a flat panel detector. The potential extension in dynamic range offered by our method was investigated for generic flat panel detectors using analytical expressions and simulations. The performance of the proposed dual-exposure approach in realistic imaging environments was compared with that of a regular single-exposure technique using experimental data from two different phantoms. Image quality was assessed in terms of signal-to-noise ratio, contrast, and analysis of profiles drawn on the images. The dynamic range, measured as the ratio between the exposure for saturation and the exposure equivalent to instrumentation noise, was increased from 76.9 to 166.7 when using our method. Dual-exposure results showed higher contrast-to-noise ratio and contrast resolution than the single-exposure acquisitions for the same x-ray dose. In addition, image artifacts were reduced in the combined dataset. This technique to extend the dynamic range of the detector without increasing the dose is particularly suited to image samples that contain both low and high attenuation regions.

  10. Efficient E-Beam Lithography Exposure Strategies for Diffractive X-ray Optics

    SciTech Connect

    Guzenko, V. A.; Vila-Comamala, J.; Gorelick, S.; David, C.; Romijn, J.

    2011-09-09

    Exposure of structures with rotational symmetry by means of electron beam lithography is not trivial, because the e-beam writers are usually designed to deal with the data defined in Cartesian coordinates. Fabrication of circular nanostructures like Fresnel zone plates (FZPs) for x-ray microscopy applications requires exposures with resolution well below 1 nm. Therefore, special attention has to be paid to the efficient exposure data preparation, which will guarantee required precision and allow keeping the exposure time low. In this article, we describe in detail an optimized strategy that was applied for exposure of FZPs by the Vistec EBPG5000Plus e-beam lithography tool. Direct programming of exposure files allowed us to use fully the capabilities of this e-beam writer to expose efficiently and reproducibly FZPs with desired characteristics in both positive and negative tone resists.

  11. X-ray dose reduction through adaptive exposure in fluoroscopic imaging.

    PubMed

    Burion, Steve; Funk, Tobias

    2011-09-11

    X-ray fluoroscopy is widely used for image guidance during cardiac intervention. However, radiation dose in these procedures can be high, and this is a significant concern, particularly in pediatric applications. Pediatrics procedures are in general much more complex than those performed on adults and thus are on average four to eight times longer. Furthermore, children can undergo up to 10 fluoroscopic procedures by the age of 10, and have been shown to have a three-fold higher risk of developing fatal cancer throughout their life than the general population. We have shown that radiation dose can be significantly reduced in adult cardiac procedures by using our scanning beam digital x-ray (SBDX) system-- a fluoroscopic imaging system that employs an inverse imaging geometry (Figure 1, Movie 1 and Figure 2). Instead of a single focal spot and an extended detector as used in conventional systems, our approach utilizes an extended X-ray source with multiple focal spots focused on a small detector. Our X-ray source consists of a scanning electron beam sequentially illuminating up to 9,000 focal spot positions. Each focal spot projects a small portion of the imaging volume onto the detector. In contrast to a conventional system where the final image is directly projected onto the detector, the SBDX uses a dedicated algorithm to reconstruct the final image from the 9,000 detector images. For pediatric applications, dose savings with the SBDX system are expected to be smaller than in adult procedures. However, the SBDX system allows for additional dose savings by implementing an electronic adaptive exposure technique. Key to this method is the multi-beam scanning technique of the SBDX system: rather than exposing every part of the image with the same radiation dose, we can dynamically vary the exposure depending on the opacity of the region exposed. Therefore, we can significantly reduce exposure in radiolucent areas and maintain exposure in more opaque regions. In our

  12. A novel method of microneedle array fabrication using inclined deep x-ray exposure

    NASA Astrophysics Data System (ADS)

    Moon, Sang Jun; Jin, Chun Yan; Lee, Seung S.

    2006-04-01

    We report a novel fabrication method for the microneedle array with a 3-dimentional feature and its replication method; ''Hot-pressing'' process with bio-compatible material, PLLA (Poly L-LActide). Using inclined deep X-ray exposure technique, we fabricate a band type microneedle array with a single body on the same material basement. Since the single body feature does not make adhesion problem with the microneedle shank and basement during peel-off step of a mold, the PMMA (Poly-Methyl-MethAcrylate) microneedle array mold insert can be used for mold process which is used with the soft material mold, PDMS (Poly-Di- Methyl-Siloxane). The side inclined deep X-ray exposure also makes complex 3-dimentional features by the regions which are not exposed during twice successive exposure steps. In addition, the successive exposure does not need an additional mask alignment after the first side exposure. The fabricated band type microneedle array mold inserts are assembled for large area patch type out-of-plane microneedle array. The bio-compatible microneedle array can be fabricated to the laboratory scale mass production by the single body PMMA mold insert and ''Hot-pressing'' process.

  13. A practical exposure-equivalent metric for instrumentation noise in x-ray imaging systems

    NASA Astrophysics Data System (ADS)

    Yadava, G. K.; Kuhls-Gilcrist, A. T.; Rudin, S.; Patel, V. K.; Hoffmann, K. R.; Bednarek, D. R.

    2008-09-01

    The performance of high-sensitivity x-ray imagers may be limited by additive instrumentation noise rather than by quantum noise when operated at the low exposure rates used in fluoroscopic procedures. The equipment-invasive instrumentation noise measures (in terms of electrons) are generally difficult to make and are potentially not as helpful in clinical practice as would be a direct radiological representation of such noise that may be determined in the field. In this work, we define a clinically relevant representation for instrumentation noise in terms of noise-equivalent detector entrance exposure, termed the instrumentation noise-equivalent exposure (INEE), which can be determined through experimental measurements of noise-variance or signal-to-noise ratio (SNR). The INEE was measured for various detectors, thus demonstrating its usefulness in terms of providing information about the effective operating range of the various detectors. A simulation study is presented to demonstrate the robustness of this metric against post-processing, and its dependence on inherent detector blur. These studies suggest that the INEE may be a practical gauge to determine and compare the range of quantum-limited performance for clinical x-ray detectors of different design, with the implication that detector performance at exposures below the INEE will be instrumentation-noise limited rather than quantum-noise limited.

  14. Strict X-ray beam collimation for facial bones examination can increase lens exposure

    PubMed Central

    Powys, R; Robinson, J; Kench, P L; Ryan, J; Brennan, P C

    2012-01-01

    Objectives It is well accepted that collimation is a cost-effective dose-reducing tool for X-ray examinations. This phantom-based study investigated the impact of X-ray beam collimation on radiation dose to the lenses of the eyes and thyroid along with the effect on image quality in facial bone radiography. Methods A three-view series (occipitomental, occipitomental 30 and lateral) was investigated, and radiation doses to the lenses and thyroid were measured using an Unfors dosemeter. Images were assessed by six experienced observers using a visual grading analysis and a total of 5400 observations were made. Results Strict collimation significantly (p<0.0001) reduced the radiation dose to the lenses of the eyes and thyroid when using a fixed projection-specific exposure. With a variable exposure technique (fixed exit dose, to simulate the behaviour of an automatic exposure control), while strict collimation was again shown to reduce thyroid dose, higher lens doses were demonstrated when compared with larger fields of exposure. Image quality was found to significantly improve using strict collimation, with observer preference being demonstrated using visual grading characteristic curves. Conclusion The complexities of optimising radiographic techniques have been shown and the data presented emphasise the importance of examining dose-reducing strategies in a comprehensive way. PMID:22374279

  15. X-ray radiation and the risk of multiple sclerosis: Do the site and dose of exposure matter?

    PubMed Central

    Motamed, Mohammad Reza; Fereshtehnejad, Seyed-Mohammad; Abbasi, Maryam; Sanei, Mastaneh; Abbaslou, Mina; Meysami, Somayeh

    2014-01-01

    Background: The sporadic cases of radiation-activated multiple sclerosis (MS) has been previously described, with a few studies focused on the relationship between radiation and the risk of MS. The aim of our study was to evaluate the association between history of X-ray radiation and MS. Methods: This case-control study was conducted on 150 individuals including 65 MS patients and 85 age- and sex-matched healthy controls enrolled using non-probability convenient sampling. Any history of previous Xray radiation consisted of job-related X-ray exposure, radiotherapy, radiographic evaluations including chest Xray, lumbosacral X-ray, skull X-ray, paranasal sinuses (PNS) X-ray, gastrointestinal (GI) series, foot X-ray and brain CT scanning were recorded and compared between two groups. Statistical analysis was performed using independent t test, Chi square and receiver operating characteristics (ROC) curve methods through SPSS software. Results: History of both diagnostic [OR=3.06 (95% CI: 1.32-7.06)] and therapeutic [OR=7.54 (95% CI: 1.5935.76) X-ray radiations were significantly higher among MS group. Mean number of skull X-rays [0.4 (SD=0.6) vs. 0.1 (SD=0.3), p=0.004] and brain CT scanning [0.9 (SD=0.8) vs. 0.5 (SD=0.7), p=0.005] was higher in MS group as well as mean of the cumulative X-ray radiation dosage [1.84 (SD=1.70) mSv vs. 1.11 (SD=1.54) mSv; p=0.008]. Conclusion: Our study was one of the first to show higher history of X-ray radiation in patients with MS compared to healthy controls. A possible association was also found between the dose and the site exposed to X-ray radiation and risk of developing MS PMID:25695003

  16. Effect of medical x-ray exposure on subsequent reproductive outcomes in scoliosis patients

    SciTech Connect

    Visscher, W.A.

    1987-01-01

    A retrospective cohort study was done which was designed to assess the effects of medical x-ray exposure on cancer incidence among scoliosis patients. Although the primary purpose of the study was to assess cancer incidence, a secondary goal was to investigate whether diagnostic x-ray exposure is related to adverse reproductive events in the female subjects. A series of case-control analyses were done which were designed to assess these effects. Radiation exposure was measured both by total films received and by an estimate of the number of films received and by an estimate of the number of films which involved ovarian irradiation. Radiation appeared to increase a woman's risk of any adverse event in the overall analysis and her risk of a premature or low birth weight infant in the separate analyses. Radiation did not appear to be related to spontaneous abortion, complications of pregnancy or delivery or birth defects, although the results of the pregnancy complications analysis was suggestive.

  17. Comparing plasma and X-ray exposure and identifying vulnerable cell parts

    NASA Astrophysics Data System (ADS)

    Graham, Bill

    2012-10-01

    Here two issues in plasma medicine that are being addressed in a collaboration between the Centre of Plasma Physics and the School of Pharmacy at Queen's University Belfast and the Plasma Institute at York University UK will be discussed. Recent measurements of the interaction of plasmas created directly in DMEM cell medium and MDAMB-231, a human breast cancer cell line, showed evidence of reduced cell viability and of DNA damage. The same set of experiments were undertaken but with X-ray exposure. A correlation of the dependence on plasma exposure time and X-ray dose was observed which might point the way to dose definition in plasma medicine. We have also been working to identify the cell parts most vulnerable to plasma exposure. In this study a 10 kHz atmospheric pressure non-thermal plasma jet, operating in He/0.5%O2 and characterized to determine the behavior of many of the plasma species, was incident onto the surface of media containing either bacterial strains, in their planktonic and biofilm forms, or isolated bacterial plasmid DNA. The results of measurements to look for changes in plasmid structural conformation, rates of single and double strand breaks, the catalytic activity of certain bacterial enzymes, the peroxidation of lipid content of the bacterial cells, the leakage of ATP and Scanning Electron Microscope (SEM) images will be discussed.

  18. Research on reducing radiation exposure for clinical applications of X-ray attenuation

    NASA Astrophysics Data System (ADS)

    Jeon, Min-Cheol; Han, Man-Seok; So, Woon-Young; Lee, Hyeon-Guck; Kim, Yong-Kyun; Lee, Seung-Yeol

    2014-02-01

    This study was aimed at identifing areas with low radiation exposure where workers could be taken in the examination room in case that they had to hold the patients by estimating the attenuation of primary radiation and measuring the spatial distribution of scattered radiation. The laboratory equipment included on the X-ray generator, a phantom (human phantom), and a dosimeter. The experiment measured the performance of the examination system (dose reproducibility), the dose of primary radiation (X-rays), and the dose of scattered radiation (secondary radiation). Both the primary and the scattered radiation were attenuated by a factor of tube in vacuum experimental tests of the inverse square law. In this study, the attenuation was 2 ˜ 2.246 for primary radiation and 2 ˜ 2.105 for secondary radiation. Natural attenuation occurred as the X-rays passed through air, and an attenuation equation was established in this study. The equation for primary radiation (1st dose) was y = A1* exp(- x/t1)+ y0. The high-intensity contour of the direction for the cathode was wider than that of the direction for the anode, showing a wide range on the rear side of the cathode and on the rear side of the anode. We tried to find the positions where the workers' radiation exposure could be reduced. When the medical radiation workers have to hold the patient for an abdominal examination, they should be placed towards the tube anode and on the left side of the patient. For a lumbar-spine lateral examination, they should be placed towards the tube anode and behind the patient, and for a femur AP (anterior-posterior) examination, they should be placed towards the tube anode and on the right side of the patient.

  19. An old/new idea for reducing exposure to x-rays

    SciTech Connect

    Colquitt, W.N.; Richards, A.G.

    1982-11-01

    In 1925 the patient's exposure to x-radiation was reduced 50 percent by the application of emulsion to both sides of the dental film. Another similar reduction is possible when the layers of emulsion are once again doubled. The authors have rediscovered this idea and tested it. A double film packet containing films which are hinged on one side for proper reorientation after developing was produced. The films were exposed to half the radiation given to normal packets. It was found that density, contrast, and definition were all comparable to normal exposures when allowances were made for an additional layer of blue-tinted film base. In addition to reduced exposure to x-rays, the folded-film technique gives a second view of the exposed area. An underexposed view is obtained by viewing either side of the folded film alone. This underexposed view offers some details not seen on fully exposed films.

  20. Radiation exposures of cancer patients from medical X-rays: how relevant are they for individual patients and population exposure?

    PubMed

    Brix, Gunnar; Nissen-Meyer, Sven; Lechel, Ursula; Nissen-Meyer, Johannes; Griebel, Jürgen; Nekolla, Elke A; Becker, Christoph; Reiser, Maximilian

    2009-11-01

    X-ray procedures have a substantial impact not only on patient care but also on man-made radiation exposure. Since a reliable risk-benefit analysis of medical X-rays can only be performed for diagnosis-related groups of patients, we determined specific exposure data for patients with the ten most common types of cancer. For all patients with the considered cancers undergoing medical X-ray procedures in a maximum-care hospital between 2000 and 2005, patient- and examination-specific data were retrieved from the hospital/radiology information system. From this data, the cumulative 5-year effective dose was estimated for each patient as well as the mean annual effective dose per patient and the mean patient observation time for each cancer site. In total, 151,439 radiographic, fluoroscopic, and CT procedures, carried out in 15,866 cancer patients (age, 62+/-13 years), were evaluated. The mean 5-year cumulative dose varied between 8.6 mSv (prostate cancer) and 68.8 mSv (pancreas cancer). Due to an increasing use of CT scans, the mean annual effective dose per patient increased from 13.6 to 18.2 mSv during the 6-year period. Combining the results obtained in this study for a particular hospital with cancer incidence data for Germany, we estimated that cancer patients having X-ray studies constitute at least 1% of the population but receive more than 10% of the total effective dose related to all medical X-ray procedures performed nationwide per year. A large fraction of this dose is radiobiologically ineffective due to the reduced life expectancy of cancer patients.

  1. Doses under automatic exposure control (AEC) for direct digital radiographic (DDR) X-ray systems.

    PubMed

    Bowden, Louise; Faulkner, Ronan; Clancy, Conor; Gallagher, Aoife; Devine, Mark; Gorman, Dermot; O'Reilly, Geraldine; Dowling, Anita

    2011-09-01

    Current guidelines quote tolerances for automatic exposure control (AEC) device performance for X-ray systems as 'Baseline ± X %'. However, in the situation where a baseline figure has not yet been achieved, as in the case of commissioning assessments, this tolerance is not relevant. The purpose of this work is to provide mean doses for direct digital radiography (DDR) X-ray system, operating in AEC, against which comparisons can be made. Dose measurements have been recorded under AEC operation on 29 DDR detectors from three different manufacturers. Two different testing protocols were examined: (1) water equivalent phantoms in front of the DDR detector and (2) aluminium block at the tube head. The average patient exit dose, using the aluminium block was 4.6 μGy with the antiscatter grid in place and 4.0 μGy with the grid removed. Using the water phantoms, the average dose was measured at 17.1 μGy with the antiscatter grid in place and 5.4 μGy with grid removed. Based on these results, it is clear that different testing configurations significantly impact on the measured dose.

  2. Observations and Considerations on Patient X-ray Exposure in the Electrophysiology Lab

    PubMed Central

    Jiang, Xianxian

    2013-01-01

    To assess patient radiation during catheter ablation procedures and operator differences. From 84 patients (51 males, age 63 ± 10 years) undergoing complex catheter ablation by three experienced operators we collected: body mass index (BMI), procedure type and time, fluoroscopy time, dose area product (DAP), air kerma and X-ray system setting (cine, collimation and angiographic imaging angle). A new factor, fluoroscopy DAP–fluoroscopy time ratio, was introduced to compare operator differences. The results show the average procedure time was 179 (± 57) minutes (min), fluoroscopy time was 31 (± 21) min, DAP was 26.4 (± 19.6) Gy.cm2 and air kerma was 0.26 (± 0.19) Gy. Procedure types were: pulmonary vein isolation (PVI) (52 %), redo PVI (11 %), pulmonary vein ablation catheter (PVAC) (14 %), ventricular tachycardia (VT) (8 %) and others (15 %). Inter-operator difference was observed in fluoroscopy and cine usage. Fluoroscopy DAP-time ratios showed a similar level of patient radiation dose rate by operator A and B (correlation: 0.89), and a significantly higher dose rate by operator C (correlation: 0.20, p<0.001; 0.26, p<0.01, to operator A and B). In conclusion, operators should be aware of patient radiation exposure levels and the influencing factors. Inter- and intra-operator differences can be measured and bench marked for improvement in X-ray efficiency and patient radiation reduction. PMID:26835055

  3. Observations and Considerations on Patient X-ray Exposure in the Electrophysiology Lab.

    PubMed

    Jiang, Xianxian; Dekker, Lukas Rc

    2013-11-01

    To assess patient radiation during catheter ablation procedures and operator differences. From 84 patients (51 males, age 63 ± 10 years) undergoing complex catheter ablation by three experienced operators we collected: body mass index (BMI), procedure type and time, fluoroscopy time, dose area product (DAP), air kerma and X-ray system setting (cine, collimation and angiographic imaging angle). A new factor, fluoroscopy DAP-fluoroscopy time ratio, was introduced to compare operator differences. The results show the average procedure time was 179 (± 57) minutes (min), fluoroscopy time was 31 (± 21) min, DAP was 26.4 (± 19.6) Gy.cm(2) and air kerma was 0.26 (± 0.19) Gy. Procedure types were: pulmonary vein isolation (PVI) (52 %), redo PVI (11 %), pulmonary vein ablation catheter (PVAC) (14 %), ventricular tachycardia (VT) (8 %) and others (15 %). Inter-operator difference was observed in fluoroscopy and cine usage. Fluoroscopy DAP-time ratios showed a similar level of patient radiation dose rate by operator A and B (correlation: 0.89), and a significantly higher dose rate by operator C (correlation: 0.20, p<0.001; 0.26, p<0.01, to operator A and B). In conclusion, operators should be aware of patient radiation exposure levels and the influencing factors. Inter- and intra-operator differences can be measured and bench marked for improvement in X-ray efficiency and patient radiation reduction.

  4. Exposure of the Swiss population by medical x-rays: 2008 review.

    PubMed

    Samara, Eleni Theano; Aroua, Abbas; Bochud, François O; Ott, Barbara; Theiler, Thomas; Treier, Reto; Trueb, Philipp R; Vader, John-Paul; Verdun, Francis R

    2012-03-01

    Nationwide surveys on radiation dose to the population from medical radiology are recommended in order to follow the trends in population exposure and ensure radiation protection.The last survey in Switzerland was conducted in 1998,and the annual effective dose from medical radiology was estimated to be 1 mSv y j(-1) per capita. The purpose of this work was to follow the trends in diagnostic radiology between 1998 and 2008 in Switzerland and determine the contribution of different modalities and types of examinations to the collective effective dose from medical x-rays. For this reason, an online database(www.raddose.ch) was developed. All healthcare providers who hold a license to run an x-ray unit in the country were invited to participate in the survey. More than 225 examinations, covering eight radiological modalities, were included in the survey. The average effective dose for each examination was reassessed. Data from about 3,500 users were collected (42% response rate). The survey showed that the annual effective dose was 1.2 mSv/capita in 2008. The most frequent examinations are conventional and dental radiographies (88%). The contribution of computed tomography was only 6% in terms of examination frequency but 68% in terms of effective dose. The comparison with other countries showed that the effective dose per capita in Switzerland was in the same range as in other countries with similar healthcare systems, although the annual number of examinations performed in Switzerland was higher.

  5. Creation of a dental X-ray unit with a contactless exposure control switch.

    PubMed

    Yoshida, M; Honda, E; Notsu, M; Maeda, N; Hosoki, H

    2014-01-01

    A new dental radiographic unit (DXRU) with a contactless switch for adjusting exposure conditions and a foot-pedal exposure switch was developed to prevent bacterial or viral contamination from patients and was compared with a conventional DXRU with a panel push-button switch with respect to user friendliness. 45 fourth-year dental school students carried out intraoral radiography using both types of DXRU. Errors regarding dose shortages of X-rays were compared and a questionnaire completed. 22 (49%) of the 45 students failed to provide the correct radiographic exposure and the number of errors was 32 for the conventional DXRU, and 4 (9%) students failed to provide the correct radiographic exposure and the number of errors was 4 for our new DXRU, at the first stage (p < 0.001). At the second stage, the number of students who failed to provide the correct radiographic exposure and the number of errors decreased to 12 and 16, respectively, for the conventional DXRU (p < 0.05). 37 (82%) of the 45 students preferred our DXRU because of its contactless switch and the push-pedal exposure switch. These data suggested that our new contactless mechanism should be used for other DXRUs for contamination control.

  6. Comparative study of spermatogonial survival after X-ray exposure, high LET (HZE) irradiation or spaceflight

    NASA Technical Reports Server (NTRS)

    Sapp, W. J.; Williams, C. S.; Williams, J. W.; Philpott, D. E.; Kato, K.; Miquel, J. M.; Serova, L.

    1992-01-01

    Spermatogonial cell loss has been observed in rats flown on Space Lab 3, Cosmos 1887, Cosmos 2044 and in mice following irradiation with X-ray or with HZE particle beams. Spermatogonial loss is determined by cell counting in maturation stage-6 seminferous tubules. With the exception of iron, laboratory irradiation experiments (with mice) revealed a similar pattern of spermatogonial loss proportional to the radiation dose at levels less than 0.1 Gy. Helium and argon irradiation resulted in a 5-percent loss of spermatogonia after only 0.01 Gy exposure. Significant spermatogonial loss (45 percent) occurred at this radiation level with iron particle beams. The loss of spermatogonia during each spaceflight was less than 10 percent when compared to control (nonflight) animals.

  7. Comparative study of spermatogonial survival after X-ray exposure, high LET (HZE) irradiation or spaceflight

    NASA Technical Reports Server (NTRS)

    Sapp, W. J.; Williams, C. S.; Williams, J. W.; Philpott, D. E.; Kato, K.; Miquel, J. M.; Serova, L.

    1992-01-01

    Spermatogonial cell loss has been observed in rats flown on Space Lab 3, Cosmos 1887, Cosmos 2044 and in mice following irradiation with X-ray or with HZE particle beams. Spermatogonial loss is determined by cell counting in maturation stage-6 seminferous tubules. With the exception of iron, laboratory irradiation experiments (with mice) revealed a similar pattern of spermatogonial loss proportional to the radiation dose at levels less than 0.1 Gy. Helium and argon irradiation resulted in a 5-percent loss of spermatogonia after only 0.01 Gy exposure. Significant spermatogonial loss (45 percent) occurred at this radiation level with iron particle beams. The loss of spermatogonia during each spaceflight was less than 10 percent when compared to control (nonflight) animals.

  8. Immediate screening of lead exposure in the workplace using portable X-ray fluorescence

    PubMed Central

    Gorce, Jean-Philippe; Roff, Martin

    2016-01-01

    ABSTRACT The use of a portable X-ray fluorescence spectrometer (PXRF) equipped with a miniaturised X-ray tube producing a small 8 mm diameter X-ray beam required the validation of two new sampling protocols for the immediate screening of occupational lead exposure. First, lead in dust and fumes, collected by Institute of Occupational Medicine (IOM) inhalable samplers on 25 mm diameter membrane filters, is quantified using PXRF. To account for irregular dust deposition, the filters are rotated manually by quarter turns. Multiple PXRF readings are collected from the central region and from two locations in the outer region. The inner region is distinguishable from the outer region, but the two outer region locations are indistinguishable. High correlations (R2 > 0.99) are found between the PXRF results and historical results obtained using a reference method based on a laboratory wavelength-dispersive sequential XRF instrument (WDXRF) for lead loadings between 1–161 μg. The PXRF results from the outer regions of the filters show a bias of −13% with respect to the WDXRF. Once this bias is allowed for, 95% of all PXRF results lie within −28% and +38% of the WDXRF results. Neither instrument accounts for potential dust accumulation on the walls of the IOM sampler. Therefore, methods based on their use can only be considered semi-quantitative. Second, a protocol combining direct PXRF measurements on workplace surfaces with surface wipes is designed for immediate on-site quantification of removable surface lead residues. The quantification of such residues by this method is compared with subsequent off-site wet chemistry analysis of the surface wipes. The two methods show a good correlation (R2 ∼ 0.88). The ratio of the amount of removable residues determined by PXRF and wipe sampling is close to one with range 0.26–3.94. It is demonstrated that PXRF can be used as an effective tool for the immediate screening of occupational lead exposure. Although this

  9. Immediate screening of lead exposure in the workplace using portable X-ray fluorescence.

    PubMed

    Gorce, Jean-Philippe; Roff, Martin

    2016-01-01

    The use of a portable X-ray fluorescence spectrometer (PXRF) equipped with a miniaturised X-ray tube producing a small 8 mm diameter X-ray beam required the validation of two new sampling protocols for the immediate screening of occupational lead exposure. First, lead in dust and fumes, collected by Institute of Occupational Medicine (IOM) inhalable samplers on 25 mm diameter membrane filters, is quantified using PXRF. To account for irregular dust deposition, the filters are rotated manually by quarter turns. Multiple PXRF readings are collected from the central region and from two locations in the outer region. The inner region is distinguishable from the outer region, but the two outer region locations are indistinguishable. High correlations (R(2) > 0.99) are found between the PXRF results and historical results obtained using a reference method based on a laboratory wavelength-dispersive sequential XRF instrument (WDXRF) for lead loadings between 1-161 μg. The PXRF results from the outer regions of the filters show a bias of -13% with respect to the WDXRF. Once this bias is allowed for, 95% of all PXRF results lie within -28% and +38% of the WDXRF results. Neither instrument accounts for potential dust accumulation on the walls of the IOM sampler. Therefore, methods based on their use can only be considered semi-quantitative. Second, a protocol combining direct PXRF measurements on workplace surfaces with surface wipes is designed for immediate on-site quantification of removable surface lead residues. The quantification of such residues by this method is compared with subsequent off-site wet chemistry analysis of the surface wipes. The two methods show a good correlation (R(2) ∼ 0.88). The ratio of the amount of removable residues determined by PXRF and wipe sampling is close to one with range 0.26-3.94. It is demonstrated that PXRF can be used as an effective tool for the immediate screening of occupational lead exposure. Although this article focused on

  10. Radiation exposure to foetus and breasts from dental X-ray examinations: effect of lead shields.

    PubMed

    Kelaranta, Anna; Ekholm, Marja; Toroi, Paula; Kortesniemi, Mika

    2016-01-01

    Dental radiography may involve situations where the patient is known to be pregnant or the pregnancy is noticed after the X-ray procedure. In such cases, the radiation dose to the foetus, though low, needs to be estimated. Uniform and widely used guidance on dental X-ray procedures during pregnancy are presently lacking, the usefulness of lead shields is unclear and practices vary. Upper estimates of radiation doses to the foetus and breasts of the pregnant patient were estimated with an anthropomorphic female phantom in intraoral, panoramic, cephalometric and CBCT dental modalities with and without lead shields. The upper estimates of foetal doses varied from 0.009 to 6.9 μGy, and doses at the breast level varied from 0.602 to 75.4 μGy. With lead shields, the foetal doses varied from 0.005 to 2.1 μGy, and breast doses varied from 0.002 to 10.4 μGy. The foetal dose levels without lead shielding were <1% of the annual dose limit of 1 mSv for a member of the public. Albeit the relative shielding effect, the exposure-induced increase in the risk of breast cancer death for the pregnant patient (based on the breast dose only) and the exposure-induced increase in the risk of childhood cancer death for the unborn child are minimal, and therefore, need for foetal and breast lead shielding was considered irrelevant. Most important is that pregnancy is never a reason to avoid or to postpone a clinically justified dental radiographic examination.

  11. Radiation exposure to foetus and breasts from dental X-ray examinations: effect of lead shields

    PubMed Central

    Ekholm, Marja; Toroi, Paula; Kortesniemi, Mika

    2016-01-01

    Objectives: Dental radiography may involve situations where the patient is known to be pregnant or the pregnancy is noticed after the X-ray procedure. In such cases, the radiation dose to the foetus, though low, needs to be estimated. Uniform and widely used guidance on dental X-ray procedures during pregnancy are presently lacking, the usefulness of lead shields is unclear and practices vary. Methods: Upper estimates of radiation doses to the foetus and breasts of the pregnant patient were estimated with an anthropomorphic female phantom in intraoral, panoramic, cephalometric and CBCT dental modalities with and without lead shields. Results: The upper estimates of foetal doses varied from 0.009 to 6.9 μGy, and doses at the breast level varied from 0.602 to 75.4 μGy. With lead shields, the foetal doses varied from 0.005 to 2.1 μGy, and breast doses varied from 0.002 to 10.4 μGy. Conclusions: The foetal dose levels without lead shielding were <1% of the annual dose limit of 1 mSv for a member of the public. Albeit the relative shielding effect, the exposure-induced increase in the risk of breast cancer death for the pregnant patient (based on the breast dose only) and the exposure-induced increase in the risk of childhood cancer death for the unborn child are minimal, and therefore, need for foetal and breast lead shielding was considered irrelevant. Most important is that pregnancy is never a reason to avoid or to postpone a clinically justified dental radiographic examination. PMID:26313308

  12. Variations in film exposure, effective kVp, and HVL among thirty-five dental x-ray units

    SciTech Connect

    Preece, J.W.; Jensen, C.W.

    1983-12-01

    Speed group ''E'' dental films were exposed in thirty-five dental x-ray units and processed under rigidly controlled conditions. The exposure, in milliroentgens required to produce an overall film density between 0.85 and 1.05 density units at the 9 mm. step of an aluminum step-wedge, ranged from 94 to 186 mR. The wide range in normalized exposure required to produce a standard density of 1.0 was associated with half-value layer and effective operating kilovoltage in only a general way. The half-value layer of thirty-five dental x-ray units ranged from 1.9 to 2.9 mm. Al, and their effective operating kilovoltages ranged from 62 to 77 kVp when units were set at 70 kVp. The exposure required to produce a specific radiographic density depended largely on the individual characteristics of the x-ray unit used.

  13. Exposure to Low-Dose X-Ray Radiation Alters Bone Progenitor Cells and Bone Microarchitecture.

    PubMed

    Lima, Florence; Swift, Joshua M; Greene, Elisabeth S; Allen, Matthew R; Cunningham, David A; Braby, Leslie A; Bloomfield, Susan A

    2017-10-01

    Exposure to high-dose ionizing radiation during medical treatment exerts well-documented deleterious effects on bone health, reducing bone density and contributing to bone growth retardation in young patients and spontaneous fracture in postmenopausal women. However, the majority of human radiation exposures occur in a much lower dose range than that used in the radiation oncology clinic. Furthermore, very few studies have examined the effects of low-dose ionizing radiation on bone integrity and results have been inconsistent. In this study, mice were irradiated with a total-body dose of 0.17, 0.5 or 1 Gy to quantify the early (day 3 postirradiation) and delayed (day 21 postirradiation) effects of radiation on bone microarchitecture and bone marrow stromal cells (BMSCs). Female BALBc mice (4 months old) were divided into four groups: irradiated (0.17, 0.5 and 1 Gy) and sham-irradiated controls (0 Gy). Micro-computed tomography analysis of distal femur trabecular bone from animals at day 21 after exposure to 1 Gy of X-ray radiation revealed a 21% smaller bone volume (BV/TV), 22% decrease in trabecular numbers (Tb.N) and 9% greater trabecular separation (Tb.Sp) compared to sham-irradiated controls (P < 0.05). We evaluated the differentiation capacity of bone marrow stromal cells harvested at days 3 and 21 postirradiation into osteoblast and adipocyte cells. Osteoblast and adipocyte differentiation was decreased when cells were harvested at day 3 postirradiation but enhanced in cells isolated at day 21 postirradiation, suggesting a compensatory recovery process. Osteoclast differentiation was increased in 1 Gy irradiated BMSCs harvested at day 3 postirradiation, but not in those harvested at day 21 postirradiation, compared to controls. This study provides evidence of an early, radiation-induced decrease in osteoblast activity and numbers, as well as a later recovery effect after exposure to 1 Gy of X-rays, whereas osteoclastogenesis was enhanced. A better

  14. Estimated operator exposure for hand holding portable X-ray units during imaging of the equine distal extremity.

    PubMed

    Tyson, Reid; Smiley, Douglas C; Pleasant, Robert S; Daniel, Gregory B

    2011-01-01

    Hand holding of portable X-ray units is common in large animal ambulatory veterinary practice. Portable X-ray equipment manuals, veterinary teaching institutions, and state regulations discourage, or prohibit, hand holding of portable X-ray units. Our goal was to quantify surface radiation leakage of a typical portable X-ray unit and to measure operator exposure at simulated hand and collar positions during imaging of the equine distal extremity. Each exposure for the study was performed at 80 kVp and 7.5 mAs and repeated 10 times. Measurement of tube radiation leakage was performed along each surface of the portable X-ray unit. To determine the operator exposure more accurately, an equine cadaver limb was used to generate scatter radiation for the following views: lateral carpus, lateral foot, palmaroproximal-palmarodistal, and dorsal 60° proximal-palmarodistal obliques of the navicular region. A Pancake Ion Chamber was placed at the handle and at simulated collar position to record estimated occupational exposure. To estimate the effect of lead shielding, exposure measurements were performed within the primary beam and behind a 0.5 mm lead equivalent apron and within an >0.5 mm lead equivalent glove. The average hand and collar dose was 0.471 and 0.327 mR/exposure, respectively. The lead apron and glove attenuated the primary beam 96.9 and 99.2%, respectively. This reduced average hand and collar exposures to 0.0038 and 0.0101 mR/exposure, respectively. Theoretical occupational limits are reached for the collar (whole body) before the hand (extremity).

  15. Hematological effects of unilateral and bilateral exposures of dogs to 300-kVp X rays

    SciTech Connect

    Baltschukat, K.; Nothdurft, W. )

    1990-07-01

    Accidental exposures to ionizing radiation from external sources usually result in an inhomogeneous dose distribution rather than a homogeneous total-body irradiation (TBI). To study the hematological effects of an inhomogeneous dose distribution, dogs were unilaterally exposed to a beam of 300 kVp X rays (HVL = 3.8 mm Cu) with their left side directed to the source. The entrance and exit surface doses were 3.8 Gy and 0.9 Gy, respectively. Dose measurements performed in bone marrow spaces of various bones revealed a maximum of 3.1 Gy in the head of the left humerus and a minimum of 0.9 Gy in the right iliac crest. Based on survival for granulocyte-macrophage progenitor cells (GM-CFC) determined in different bone marrow sites 24 h after the exposure, the dose-dependent reduction ranged from 0.44 to 16% of the control values. The regeneration of the GM-CFC compartments in the various bone marrow spaces showed patterns which were independent of each other up to Day 28. Values were normal again at Day 125 after exposure. For comparative purposes, three dogs were exposed bilaterally to achieve a homogeneous dose distribution. They received a TBI of 2.4 Gy, which according to previous calculations should have caused the same systemic damage to the GM-CFC compartment as the unilateral exposure. The peripheral blood cell changes, including the GM-CFC, and the colony stimulating activity in the serum showed a similar pattern for both exposures. These findings support the hypothesis that the overall survival fraction of progenitor cells in the bone marrow is the main determinant of the blood cell changes, independent of the anatomical distribution.

  16. Shorter Exposures to Harder X-Rays Trigger Early Apoptotic Events in Xenopus laevis Embryos

    PubMed Central

    Dong, JiaJia; Mury, Sean P.; Drahos, Karen E.; Moscovitch, Marko

    2010-01-01

    Background A long-standing conventional view of radiation-induced apoptosis is that increased exposure results in augmented apoptosis in a biological system, with a threshold below which radiation doses do not cause any significant increase in cell death. The consequences of this belief impact the extent to which malignant diseases and non-malignant conditions are therapeutically treated and how radiation is used in combination with other therapies. Our research challenges the current dogma of dose-dependent induction of apoptosis and establishes a new parallel paradigm to the photoelectric effect in biological systems. Methodology/Principal Findings We explored how the energy of individual X-ray photons and exposure time, both factors that determine the total dose, influence the occurrence of cell death in early Xenopus embryo. Three different experimental scenarios were analyzed and morphological and biochemical hallmarks of apoptosis were evaluated. Initially, we examined cell death events in embryos exposed to increasing incident energies when the exposure time was preset. Then, we evaluated the embryo's response when the exposure time was augmented while the energy value remained constant. Lastly, we studied the incidence of apoptosis in embryos exposed to an equal total dose of radiation that resulted from increasing the incoming energy while lowering the exposure time. Conclusions/Significance Overall, our data establish that the energy of the incident photon is a major contributor to the outcome of the biological system. In particular, for embryos exposed under identical conditions and delivered the same absorbed dose of radiation, the response is significantly increased when shorter bursts of more energetic photons are used. These results suggest that biological organisms display properties similar to the photoelectric effect in physical systems and provide new insights into how radiation-mediated apoptosis should be understood and utilized for therapeutic

  17. Low-Dose CT of the Paranasal Sinuses: Minimizing X-Ray Exposure with Spectral Shaping.

    PubMed

    Wuest, Wolfgang; May, Matthias; Saake, Marc; Brand, Michael; Uder, Michael; Lell, Michael

    2016-11-01

    Shaping the energy spectrum of the X-ray beam has been shown to be beneficial in low-dose CT. This study's aim was to investigate dose and image quality of tin filtration at 100 kV for pre-operative planning in low-dose paranasal CT imaging in a large patient cohort. In a prospective trial, 129 patients were included. 64 patients were randomly assigned to the study protocol (100 kV with additional tin filtration, 150mAs, 192x0.6-mm slice collimation) and 65 patients to the standard low-dose protocol (100 kV, 50mAs, 128 × 0.6-mm slice collimation). To assess the image quality, subjective parameters were evaluated using a five-point scale. This scale was applied on overall image quality and contour delineation of critical anatomical structures. All scans were of diagnostic image quality. Bony structures were of good diagnostic image quality in both groups, soft tissues were of sufficient diagnostic image quality in the study group because of a high level of noise. Radiation exposure was very low in both groups, but significantly lower in the study group (CTDIvol 1.2 mGy vs. 4.4 mGy, p < 0.001). Spectral optimization (tin filtration at 100 kV) allows for visualization of the paranasal sinus with sufficient image quality at a very low radiation exposure. • Spectral optimization (tin filtration) is beneficial to low-dose parasinus CT • Tin filtration at 100 kV yields sufficient image quality for pre-operative planning • Diagnostic parasinus CT can be performed with an effective dose <0.05 mSv.

  18. Lung ultrasound and chest x-ray for detecting pneumonia in an acute geriatric ward

    PubMed Central

    Ticinesi, Andrea; Lauretani, Fulvio; Nouvenne, Antonio; Mori, Giulia; Chiussi, Giulia; Maggio, Marcello; Meschi, Tiziana

    2016-01-01

    Abstract Background: Our aim was to compare the accuracy of lung ultrasound (LUS) and standard chest x-ray (CXR) for diagnosing pneumonia in older patients with acute respiratory symptoms (dyspnea, cough, hemoptysis, and atypical chest pain) admitted to an acute-care geriatric ward. Methods: We enrolled 169 (80 M, 89 F) multimorbid patients aged 83.0 ± 9.2 years from January 1 to October 31, 2015. Each participant underwent CXR and bedside LUS within 6 hours from ward admission. LUS was performed by skilled clinicians, blinded to CXR results and clinical history. The final diagnosis (pneumonia vs no-pneumonia) was established by another clinician reviewing clinical and laboratory data independent of LUS results and possibly prescribing chest contrast-enhanced CT. Diagnostic parameters of CXR and LUS were compared with McNemar test on the whole cohort and after stratification for Rockwood Clinical Frailty Scale. Results: Diagnostic accuracy for pneumonia (96 patients) was significantly higher in LUS (0.90, 95% confidence interval [CI] 0.83–0.96) compared with CXR (0.67, 95%CI 0.60–0.74, P < 0.001). LUS had a better sensitivity (0.92, 95%CI 0.86–0.97 vs 0.47, 95%CI 0.37–0.57) and negative predictive value (0.95, 95% CI 0.83–0.96 vs 0.57, 95%CI 0.48–0.56). In those patients with frailty (n = 87 with Rockwood Clinical Frailty Scale ≥5), LUS maintained a high diagnostic accuracy, but CXR did not (P = 0.0003). Interobserver agreement for LUS, calculated in a subsample of 29 patients, was high (k = 0.90). Conclusions: In multimorbid patients admitted to an acute geriatric ward, LUS was more accurate than CXR for the diagnosis of pneumonia, particularly in those with frailty. A wider use of LUS should be implemented in this setting. PMID:27399134

  19. X-rays for Acute Knee Injuries: Pre- and Post- Pittsburgh Decision Rules Implementation. A District General Hospital Experience.

    PubMed

    El Ashry, Saad R; El Gamal, Tarek A; Challagundla, Sudhakar R; Ntala, Chara A; Nagy, Ahmed M; Crane, Evan O

    2016-10-28

    We wanted to assess the number of unnecessary radiographs done for acute knee injury patients and the accuracy of the Pittsburgh decision rules. A retrospective observational study was done to look at the acute knee injury patients presented to a district general hospital Accident and Emergency Department from August 2011 till August 2013. We assessed the following parameters: sex, age, mechanism of injury, weight-bearing status and incidence of fractures in patients subjected to plain radiograph. A prospective study was then done from April 2014- August 2014 following implementation of the Pittsburgh decision rules. 24% of the patients had knee X-ray, compared to 72.12% in the first cycle. 36.8% had fracture, compared to 6.1% first cycle, with 66.7 % reduction in x-rays. Pittsburgh decision rules sensitivity was 100% and specificity 85.3%, positive predictive value 45.8% and accuracy 87%. 1. The Pittsburgh decision rules is highly sensitive, specific and accurate in determining the need of X-ray in acute knee Injuries. 2. We found that the Pittsburgh decision rules performs well in our hospital, which coincides with previously published literature.

  20. Signal-to-noise and radiation exposure considerations in conventional and diffraction x-ray microscopy

    DOE PAGES

    Huang, Xiaojing; Miao, Huijie; Steinbrener, Jan; ...

    2009-01-01

    Using a signal-to-noise ratio estimation based on correlations between multiple simulated images, we compare the dose efficiency of two soft x-ray imaging systems: incoherent brightfield imaging using zone plate optics in a transmission x-ray microscope (TXM), and x-ray diffraction microscopy (XDM) where an image is reconstructed from the far-field coherent diffraction pattern. In XDM one must computationally phase weak diffraction signals; in TXM one suffers signal losses due to the finite numerical aperture and efficiency of the optics. In simulations with objects representing isolated cells such as yeast, we find that XDM has the potential for delivering equivalent resolution imagesmore » using fewer photons. As a result, this can be an important advantage for studying radiation-sensitive biological and soft matter specimens.« less

  1. Signal-to-noise and radiation exposure considerations in conventional and diffraction x-ray microscopy.

    PubMed

    Huang, Xiaojing; Miao, Huijie; Steinbrener, Jan; Nelson, Johanna; Shapiro, David; Stewart, Andrew; Turner, Joshua; Jacobsen, Chris

    2009-08-03

    Using a signal-to-noise ratio estimation based on correlations between multiple simulated images, we compare the dose efficiency of two soft x-ray imaging systems: incoherent brightfield imaging using zone plate optics in a transmission x-ray microscope (TXM), and x-ray diffraction microscopy (XDM) where an image is reconstructed from the far-field coherent diffraction pattern. In XDM one must computationally phase weak diffraction signals; in TXM one suffers signal losses due to the finite numerical aperture and efficiency of the optics. In simulations with objects representing isolated cells such as yeast, we find that XDM has the potential for delivering equivalent resolution images using fewer photons. This can be an important advantage for studying radiation-sensitive biological and soft matter specimens.

  2. Signal-to-noise and radiation exposure considerations in conventional and diffraction x-ray microscopy

    PubMed Central

    Huang, Xiaojing; Miao, Huijie; Steinbrener, Jan; Nelson, Johanna; Shapiro, David; Stewart, Andrew; Turner, Joshua; Jacobsen, Chris

    2010-01-01

    Using a signal-to-noise ratio estimation based on correlations between multiple simulated images, we compare the dose efficiency of two soft x-ray imaging systems: incoherent brightfield imaging using zone plate optics in a transmission x-ray microscope (TXM), and x-ray diffraction microscopy (XDM) where an image is reconstructed from the far-field coherent diffraction pattern. In XDM one must computationally phase weak diffraction signals; in TXM one suffers signal losses due to the finite numerical aperture and efficiency of the optics. In simulations with objects representing isolated cells such as yeast, we find that XDM has the potential for delivering equivalent resolution images using fewer photons. This can be an important advantage for studying radiation-sensitive biological and soft matter specimens. PMID:19654762

  3. Signal-to-noise and radiation exposure considerations in conventional and diffraction x-ray microscopy

    SciTech Connect

    Huang, Xiaojing; Miao, Huijie; Steinbrener, Jan; Nelson, Johanna; Shapiro, David; Stewart, Andrew; Turner, Joshua; Jacobsen, Chris

    2009-01-01

    Using a signal-to-noise ratio estimation based on correlations between multiple simulated images, we compare the dose efficiency of two soft x-ray imaging systems: incoherent brightfield imaging using zone plate optics in a transmission x-ray microscope (TXM), and x-ray diffraction microscopy (XDM) where an image is reconstructed from the far-field coherent diffraction pattern. In XDM one must computationally phase weak diffraction signals; in TXM one suffers signal losses due to the finite numerical aperture and efficiency of the optics. In simulations with objects representing isolated cells such as yeast, we find that XDM has the potential for delivering equivalent resolution images using fewer photons. As a result, this can be an important advantage for studying radiation-sensitive biological and soft matter specimens.

  4. Exposure Dose Reconstruction from EPR Spectra of Tooth Enamel Exposed to the Combined Effect of X-rays and Gamma Radiation

    NASA Astrophysics Data System (ADS)

    Kirillov, V. A.; Kuchuro, J. I.

    2014-09-01

    We have used EPR dosimetry on tooth enamel to show that the combined effect of x-rays with effective energy 34 keV and gamma radiation with average energy 1250 keV leads to a significant increase in the reconstructed absorbed dose compared with the applied dose from a gamma source or from an x-ray source or from both sources of electromagnetic radiation. In simulation experiments, we develop an approach to estimating the contribution of diagnostic x-rays to the exposure dose formed in the tooth enamel by the combined effect of x-rays and gamma radiation.

  5. X-ray photoelectron spectroscopy studies of the sodium chloride surface after laser exposure

    NASA Astrophysics Data System (ADS)

    Savintsev, A. P.; Gavasheli, Yu O.; Kalazhokov, Z. Kh; Kalazhokov, Kh Kh

    2016-11-01

    The surface of NaCl crystals outside and in the crater was examined using an x-ray photoelectron spectrometer. The comparative analysis of the XPS spectra showed that high- intensity laser irradiation has a significant impact on the state and composition of the surface of the ionic crystal.

  6. X-Ray Exposure of Electron-Deposited Photoresist for Conformal Lithography on Corrugated Surfaces

    NASA Technical Reports Server (NTRS)

    Hartley, F.; Malek, C.; Nguyen, S.

    1998-01-01

    Proximity printing using synchrotron X-ray lithography provides high resolution pattern transfer with large depth of field, low diffraction effects and no reflection from the substrate. Electro-plating of photo-resist allows deposition of thin, uniform films over geometrically complex and topographically diverse, electrically conductive surfaces.

  7. Pinch plasma source for x-ray microscopy with nanosecond exposure time.

    PubMed

    Lebert, R; Neff, W; Rothweiler, D

    1996-01-01

    The strong demand for bright, compact, and inexpensive sources for x-ray microscopy has stimulated the development of flash x-ray sources. In this paper, the requirements for such a source are analyzed under boundary conditions given by the concept of an imaging x-ray microscope using mirror condenser and Fresnel zone plates for high-resolution imaging. It is found that the Lyman-α (1s-2p) line of hydrogen-like nitrogen (N VII) at λ = 2.48 nm emitted from a nonequilibrium plasma of about 200 eV temperature and 1020 cm-3 electron density is best suited. These conditions are achieved in medium-current pinch-plasma devices. Using detailed numerical simulation of the physical processes of such a device, optimization criteria for the integrated spectral brightness (ISB) are found. Measurements of the ISB confirm these optimization criteria. The results show that the spectral emission characteristics of an optimized pinch plasma souce are compatible with the demands of the mentioned x-ray microscopy concept. These emission characteristics are compared with laser-produced plasma sources. Using the optimized source with an ISB exceeding 0.6 μJ/(μm2 sr) in a 10-20 ns pulse, wet biological samples are imaged with about 0.1 μm lateral resolution.

  8. DNA double-strand break misrejoining after exposure of primary human fibroblasts to CK characteristic X rays, 29 kVp X rays and 60Co gamma rays.

    PubMed

    Kühne, Martin; Urban, Gerhard; Frankenberg, Dieter; Löbrich, Markus

    2005-11-01

    The efficiency of ionizing photon radiation for inducing mutations, chromosome aberrations, neoplastic cell transformation, and cell killing depends on the photon energy. We investigated the induction and rejoining of DNA double-strand breaks (DSBs) as possible contributors for the varying efficiencies of different photon energies. A specialized pulsed-field gel electrophoresis assay based on Southern hybridization of single Mbp genomic restriction fragments was employed to assess DSB induction and rejoining by quantifying the restriction fragment band. Unrejoined and misrejoined DSBs were determined in dose fractionation protocols using doses per fraction of 2.2 and 4.4 Gy for CK characteristic X rays, 4 and 8 Gy for 29 kVp X rays, and 5, 10 and 20 Gy for 60Co gamma rays. DSB induction by CK characteristic X rays was about twofold higher than for 60Co gamma rays, whereas 29 kVp X rays showed only marginally elevated levels of induced DSBs compared with 60Co gamma rays (a factor of 1.15). Compared with these modest variations in DSB induction, the variations in the levels of unrejoined and misrejoined DSBs were more significant. Our results suggest that differences in the fidelity of DSB rejoining together with the different efficiencies for induction of DSBs can explain the varying biological effectiveness of different photon energies.

  9. Diagnostic x-ray exposure increases the risk of thyroid microcarcinoma: a population-based case-control study

    PubMed Central

    Zhang, Yawei; Chen, Yingtai; Huang, Huang; Sandler, Jason; Dai, Min; Ma, Shuangge; Udelsman, Robert

    2015-01-01

    Objective Thyroid cancer incidence and diagnostic x-ray exposures, particularly CT scans and nuclear medicine examinations have increased substantially in the United States. However, very few epidemiologic studies have directly investigated their associations. Methods A population-based case-control study was conducted in Connecticut in 2010–2011 including 462 histologically confirmed incident thyroid cancer cases and 498 population-based controls. Multivariate unconditional logistic regression models were used to estimate the associations between diagnostic x-rays and risk of thyroid cancer controlling for potential confounding factors. Results Exposure to any diagnostic x-rays was associated with an increased risk of well-differentiated thyroid microcarcinoma (tumor size ≤10 mm, OR=2.76, 95%CI: 1.31–5.81). The highest risk increase occurred with nuclear medicine examinations (excluding cardiology tests and thyroid uptake studies; OR=5.47, 95%CI: 2.10–14.23), followed by chest CT scans (OR=4.30, 95%CI: 1.66–11.14), head and neck CT scans (OR=3.88, 95%CI: 1.75–8.63), upper gastrointestinal series (OR=3.56, 95%CI: 1.54–8.21), lower gastrointestinal series (OR=3.29, 95%CI: 1.41–7.66), kidney x-rays involving dye injection into a vein or artery (OR=3.21, 95%CI: 1.20–8.54), mammograms (OR=2.95, 95%CI: 1.14–7.61), chest x-rays (OR=2.93, 95%CI: 1.37–6.29), and abdomen CT scans (OR=2.54, 95%CI: 1.02–6.30). No significant associations were found between these imaging modalities and thyroid tumors larger than 10 mm. Conclusions This study provides the first direct evidence that CT scans and nuclear medicine examinations are associated with an increased risk of thyroid cancer. The novel finding that an array of diagnostic x-ray procedures are associated thyroid microcarcinomas warrants further investigation. PMID:25932870

  10. Selenium Preferentially Accumulates in the Eye Lens Following Embryonic Exposure: A Confocal X-ray Fluorescence Imaging Study

    SciTech Connect

    Choudhury, Sanjukta; Thomas, Jith; Sylvain, Nicole J.; Ponomarenko, Olena; Gordon, Robert A.; Heald, Steve M.; Janz, David M.; Krone, Patrick H.; Coulthard, Ian; George, Graham N.; Pickering, Ingrid J.

    2015-02-17

    Maternal transfer of elevated selenium (Se) to offspring is an important route of Se exposure for fish in the natural environment. However, there is a lack of information on the tissue specific spatial distribution and speciation of Se in the early developmental stages of fish, which provide important information about Se toxicokinetics. The effect of maternal transfer of Se was studied by feeding adult zebrafish a Se-elevated or a control diet followed by collection of larvae from both groups. Novel confocal synchrotron-based techniques were used to investigate Se within intact preserved larvae. Confocal X-ray fluorescence imaging was used to compare Se distributions within specific planes of an intact larva from each of the two groups. The elevated Se treatment showed substantially higher Se levels than the control; Se preferentially accumulated to highest levels in the eye lens, with lower levels in the retina, yolk and other tissues. Confocal X-ray absorption spectroscopy was used to determine that the speciation of Se within the eye lens of the intact larva was a selenomethionine-like species. Preferential accumulation of Se in the eye lens may suggest a direct cause-and-effect relationship between exposure to elevated Se and Se-induced ocular impairments reported previously. This study illustrates the effectiveness of confocal X-ray fluorescence methods for investigating trace element distribution and speciation in intact biological specimens

  11. X-ray absorptiometry of the breast using mammographic exposure factors: application to units featuring automatic beam quality selection.

    PubMed

    Kotre, C J

    2010-06-01

    A number of studies have identified the relationship between the visual appearance of high breast density at mammography and an increased risk of breast cancer. Approaches to quantify the amount of glandular tissue within the breast from mammography have so far concentrated on image-based methods. Here, it is proposed that the X-ray parameters automatically selected by the mammography unit can be used to estimate the thickness of glandular tissue overlying the automatic exposure sensor area, provided that the unit can be appropriately calibrated. This is a non-trivial task for modern mammography units that feature automatic beam quality selection, as the number of tube potential and X-ray target/filter combinations used to cover the range of breast sizes and compositions can be large, leading to a potentially unworkable number of curve fits and interpolations. Using appropriate models for the attenuation of the glandular breast in conjunction with a constrained set of physical phantom measurements, it is demonstrated that calibration for X-ray absorptiometry can be achieved despite the large number of possible exposure factor combinations employed by modern mammography units. The main source of error on the estimated glandular tissue thickness using this method is shown to be uncertainty in the measured compressed breast thickness. An additional correction for this source of error is investigated and applied. Initial surveys of glandular thickness for a cohort of women undergoing breast screening are presented.

  12. Simultaneous exposure of mammalian cells to heavy ions and X-rays

    NASA Astrophysics Data System (ADS)

    Furusawa, Y.; Aoki, M.; Durante, M.

    Crews of space missions are exposed to a mixed radiation field, including sparsely and densely ionizing radiation. To determine the biological effectiveness of mixed high-/low-LET radiation fields, mammalian cells were exposed in vitro simultaneously to X-rays and heavy ions, accelerated at the HIMAC accelerator. X-ray doses ranged from 1 to 11 Gy. At the same time, cells were exposed to either 40Ar (550 MeV/n, 86 keV/μm), 28Si (100 MeV/n, 150 keV/μm), or 56Fe (115 MeV/n, 442 keV/μm) ions. Survival was measured in hamster V79 fibroblasts. Structural aberrations in chromosome 2 were measured by chemical-induced premature chromosome condensation combined with fluorescence in situ hybridization in isolated human lymphocytes. For argon and silicon experiments, measured damage in the mixed radiation field was consistent with the value expected using an additive function for low- and high-LET separated data. A small deviation from a simple additive function is observed with very high-LET iron ions combined to X-rays.

  13. A real-time regional adaptive exposure method for saving dose-area product in x-ray fluoroscopy

    SciTech Connect

    Burion, Steve; Funk, Tobias; Speidel, Michael A.

    2013-05-15

    Purpose: Reduction of radiation dose in x-ray imaging has been recognized as a high priority in the medical community. Here the authors show that a regional adaptive exposure method can reduce dose-area product (DAP) in x-ray fluoroscopy. The authors' method is particularly geared toward providing dose savings for the pediatric population. Methods: The scanning beam digital x-ray system uses a large-area x-ray source with 8000 focal spots in combination with a small photon-counting detector. An imaging frame is obtained by acquiring and reconstructing up to 8000 detector images, each viewing only a small portion of the patient. Regional adaptive exposure was implemented by varying the exposure of the detector images depending on the local opacity of the object. A family of phantoms ranging in size from infant to obese adult was imaged in anteroposterior view with and without adaptive exposure. The DAP delivered to each phantom was measured in each case, and noise performance was compared by generating noise arrays to represent regional noise in the images. These noise arrays were generated by dividing the image into regions of about 6 mm{sup 2}, calculating the relative noise in each region, and placing the relative noise value of each region in a one-dimensional array (noise array) sorted from highest to lowest. Dose-area product savings were calculated as the difference between the ratio of DAP with adaptive exposure to DAP without adaptive exposure. The authors modified this value by a correction factor that matches the noise arrays where relative noise is the highest to report a final dose-area product savings. Results: The average dose-area product saving across the phantom family was (42 {+-} 8)% with the highest dose-area product saving in the child-sized phantom (50%) and the lowest in the phantom mimicking an obese adult (23%). Conclusions: Phantom measurements indicate that a regional adaptive exposure method can produce large DAP savings without

  14. Exposure to Ionizing Radiation during Dental X-Rays Is Not Associated with Risk of Developing Meningioma: A Meta-Analysis Based on Seven Case-Control Studies

    PubMed Central

    Xu, Ping; Luo, Hong; Huang, Guang-Lei; Yin, Xin-Hai; Luo, Si-Yang; Song, Ju-Kun

    2015-01-01

    Background Many observational studies have found that exposure to dental X-rays is associated with the risk of development of meningioma. However, these findings are inconsistent. We conducted a meta-analysis to assess the relationship between exposure to dental X-rays and the risk of development of meningioma. Methods The PubMed and EMBASE databases were searched to identify eligible studies. Summary odds ratio (OR) estimates and 95% confidence intervals (95% CIs) were used to compute the risk of meningioma development according to heterogeneity. Subgroup and sensitivity analyses were performed to further explore the potential heterogeneity. Finally, publication bias was assessed. Results Seven case-control studies involving 6,174 patients and 19,459 controls were included in the meta-analysis. Neither exposure to dental X-rays nor performance of full-mouth panorex X-rays was associated with an increased risk of development of meningioma (overall: OR, 0.97; 95% CI, 0.70–1.32; dental X-rays: OR, 1.05; 95% CI, 0.89–1.25; panorex X-rays: OR, 1.01; 95% CI, 0.76–1.34). However, exposure to bitewing X-rays was associated with a slightly increased risk of development of meningioma (OR, 1.73; 95% CI, 1.28–2.34). Similar results were obtained in the subgroup and sensitivity analyses. Little evidence of publication bias was observed. Conclusion Based on the currently limited data, there is no association between exposure to dental X-rays and the risk of development of meningioma. However, these results should be cautiously interpreted because of the heterogeneity among studies. Additional large, high-quality clinical trials are needed to evaluate the association between exposure to dental X-rays and the risk of development of meningioma. PMID:25658814

  15. Exposure to ionizing radiation during dental X-rays is not associated with risk of developing meningioma: a meta-analysis based on seven case-control studies.

    PubMed

    Xu, Ping; Luo, Hong; Huang, Guang-Lei; Yin, Xin-Hai; Luo, Si-Yang; Song, Ju-Kun

    2015-01-01

    Many observational studies have found that exposure to dental X-rays is associated with the risk of development of meningioma. However, these findings are inconsistent. We conducted a meta-analysis to assess the relationship between exposure to dental X-rays and the risk of development of meningioma. The PubMed and EMBASE databases were searched to identify eligible studies. Summary odds ratio (OR) estimates and 95% confidence intervals (95% CIs) were used to compute the risk of meningioma development according to heterogeneity. Subgroup and sensitivity analyses were performed to further explore the potential heterogeneity. Finally, publication bias was assessed. Seven case-control studies involving 6,174 patients and 19,459 controls were included in the meta-analysis. Neither exposure to dental X-rays nor performance of full-mouth panorex X-rays was associated with an increased risk of development of meningioma (overall: OR, 0.97; 95% CI, 0.70-1.32; dental X-rays: OR, 1.05; 95% CI, 0.89-1.25; panorex X-rays: OR, 1.01; 95% CI, 0.76-1.34). However, exposure to bitewing X-rays was associated with a slightly increased risk of development of meningioma (OR, 1.73; 95% CI, 1.28-2.34). Similar results were obtained in the subgroup and sensitivity analyses. Little evidence of publication bias was observed. Based on the currently limited data, there is no association between exposure to dental X-rays and the risk of development of meningioma. However, these results should be cautiously interpreted because of the heterogeneity among studies. Additional large, high-quality clinical trials are needed to evaluate the association between exposure to dental X-rays and the risk of development of meningioma.

  16. Deciphering the acute cellular phosphoproteome response to irradiation with X-rays, protons and carbon ions.

    PubMed

    Winter, Martin; Dokic, Ivana; Schlegel, Julian; Warnken, Uwe; Debus, Jürgen; Abdollahi, Amir; Schnölzer, Martina

    2017-03-16

    Radiotherapy is a cornerstone of cancer therapy. The recently established particle therapy with raster-scanning protons and carbon ions landmarks a new era in the field of high-precision cancer medicine. However, molecular mechanisms governing radiation induced intracellular signaling remain elusive. Here, we present the first comprehensive proteomic and phosphoproteomic study applying stable isotope labeling by amino acids in cell culture (SILAC) in combination with high-resolution mass spectrometry to decipher cellular response to irradiation with X-rays, protons and carbon ions. At protein expression level limited alterations were observed 2h post irradiation of human lung adenocarcinoma cells. In contrast, 181 phosphorylation sites were found to be differentially regulated out of which 151 sites were not hitherto attributed to radiation response as revealed by crosscheck with the PhosphoSitePlus database. Radiation-induced phosphorylation of the p(S/T)Q motif was the prevailing regulation pattern affecting proteins involved in DNA damage response signaling. Since radiation doses were selected to produce same level of cell kill and DNA double-strand breakage for each radiation quality, DNA damage responsive phosphorylation sites were regulated to same extent. However, differential phosphorylation between radiation qualities was observed for 55 phosphorylation sites indicating the existence of distinct signaling circuitries induced by X-ray versus particle (proton/carbon) irradiation beyond the canonical DNA damage response. This unexpected finding was confirmed in targeted spike-in experiments using synthetic isotope labeled phosphopeptides. Herewith, we successfully validated uniform DNA damage response signaling coexisting with altered signaling involved in apoptosis and metabolic processes induced by X-ray and particle based treatments. In summary, the comprehensive insight into the radiation-induced phosphoproteome landscape is instructive for the design of

  17. SU-E-I-52: Effect of Various X-Ray Beam Qualities On the Exposure Index

    SciTech Connect

    Yasumatsu, S; Iwase, K; Shimizu, Y; Tanaka, N; Morishita, J

    2015-06-15

    Purpose: The exposure index (EI) proposed by the International Electrotechnical Commission (IEC) 62494-1 is expected to be utilized as a standard dose index by every manufacturer. The IEC recommended the usage of RQA5 for the EI. However, X-ray beam qualities, particularly in clinical practices, vary depending on the examination objects and exposure conditions, including usage of anti-scatter grids. We investigated the effects of the X-ray beam qualities other than RQA5 on the EI. Methods: The Xray beam qualities of RQA3, 5, 7, and 9 in IEC 61267 Ed. 1.0 were adopted in a computed radiography system. A uniform exposure without objects was performed to measure the exposure indicators (S values) and air kerma (K). The relational equations between the S values and K were derived for the determination of the EI values. The EI values for RQA3, 7, and 9 were compared to those for RQA5 at the fixed S values of 100, 200, 400, and 600. Finally, the half-value layers (HVLs) using four grids (ratio 6:1, 8:1, 10:1, and 12:1) for the RQA5 X-ray were compared to those with RQA3–9. Results: The EI values for RQA3, 7, and 9 were up to 35.3%, 11.8%, and 38.7% higher, respectively, than that for RQA5 at the S value of 600. The HVLs without grids and with various grids for RQA5 were 6.85 mm Al. and in the range of 6.94–7.29 mm Al. (ΔHVL: up to 0.44 mm Al.), respectively. This variation in the HVLs with grids was smaller than that observed for RQA3–9 (ΔHVL: 2.0–7.5 mm Al.). Conclusion: Although the usage of grids may not greatly affect the EI, the X-ray beam quality for the determination of the EI cannot be ignored in the clinical evaluation of the dose index.

  18. High-resolution short-exposure small-animal laboratory x-ray phase-contrast tomography

    SciTech Connect

    Larsson, Daniel H.; Vågberg, William; Yildirim, Ali Önder; Hertz, Hans M.

    2016-12-13

    X-ray computed tomography of small animals and their organs is an essential tool in basic and preclinical biomedical research. In both phase-contrast and absorption tomography high spatial resolution and short exposure times are of key importance. However, the observable spatial resolutions and achievable exposure times are presently limited by system parameters rather than more fundamental constraints like, e.g., dose. Here we demonstrate laboratory tomography with few-ten μm spatial resolution and few-minute exposure time at an acceptable dose for small-animal imaging, both with absorption contrast and phase contrast. The method relies on a magnifying imaging scheme in combination with a high-power small-spot liquid-metal-jet electron-impact source. Lastly, the tomographic imaging is demonstrated on intact mouse, phantoms and excised lungs, both healthy and with pulmonary emphysema.

  19. High-resolution short-exposure small-animal laboratory x-ray phase-contrast tomography

    DOE PAGES

    Larsson, Daniel H.; Vågberg, William; Yaroshenko, Andre; ...

    2016-12-13

    X-ray computed tomography of small animals and their organs is an essential tool in basic and preclinical biomedical research. In both phase-contrast and absorption tomography high spatial resolution and short exposure times are of key importance. However, the observable spatial resolutions and achievable exposure times are presently limited by system parameters rather than more fundamental constraints like, e.g., dose. Here we demonstrate laboratory tomography with few-ten μm spatial resolution and few-minute exposure time at an acceptable dose for small-animal imaging, both with absorption contrast and phase contrast. The method relies on a magnifying imaging scheme in combination with a high-powermore » small-spot liquid-metal-jet electron-impact source. Lastly, the tomographic imaging is demonstrated on intact mouse, phantoms and excised lungs, both healthy and with pulmonary emphysema.« less

  20. High-resolution short-exposure small-animal laboratory x-ray phase-contrast tomography

    PubMed Central

    Larsson, Daniel H.; Vågberg, William; Yaroshenko, Andre; Yildirim, Ali Önder; Hertz, Hans M.

    2016-01-01

    X-ray computed tomography of small animals and their organs is an essential tool in basic and preclinical biomedical research. In both phase-contrast and absorption tomography high spatial resolution and short exposure times are of key importance. However, the observable spatial resolutions and achievable exposure times are presently limited by system parameters rather than more fundamental constraints like, e.g., dose. Here we demonstrate laboratory tomography with few-ten μm spatial resolution and few-minute exposure time at an acceptable dose for small-animal imaging, both with absorption contrast and phase contrast. The method relies on a magnifying imaging scheme in combination with a high-power small-spot liquid-metal-jet electron-impact source. The tomographic imaging is demonstrated on intact mouse, phantoms and excised lungs, both healthy and with pulmonary emphysema. PMID:27958376

  1. High-resolution short-exposure small-animal laboratory x-ray phase-contrast tomography

    NASA Astrophysics Data System (ADS)

    Larsson, Daniel H.; Vågberg, William; Yaroshenko, Andre; Yildirim, Ali Önder; Hertz, Hans M.

    2016-12-01

    X-ray computed tomography of small animals and their organs is an essential tool in basic and preclinical biomedical research. In both phase-contrast and absorption tomography high spatial resolution and short exposure times are of key importance. However, the observable spatial resolutions and achievable exposure times are presently limited by system parameters rather than more fundamental constraints like, e.g., dose. Here we demonstrate laboratory tomography with few-ten μm spatial resolution and few-minute exposure time at an acceptable dose for small-animal imaging, both with absorption contrast and phase contrast. The method relies on a magnifying imaging scheme in combination with a high-power small-spot liquid-metal-jet electron-impact source. The tomographic imaging is demonstrated on intact mouse, phantoms and excised lungs, both healthy and with pulmonary emphysema.

  2. Angularly resolved X-ray photoelectron spectroscopy investigation of PTFE after prolonged space exposure

    NASA Technical Reports Server (NTRS)

    Dalins, I.; Karimi, M.

    1992-01-01

    Monochromatized angularly resolved X-ray photoelectron spectroscopy (ARXPS) was used to study PTFE (Teflon) that had been exposed to an earth orbital environment for approximately six years. The primary interest of the research is on a very reactive component of this environment (atomic oxygen) which, because of the typical orbital velocities of a spacecraft, impinge on exposed surfaces with 5 eV energy. This presentation deals with the method of analysis, the findings as they pertain to a rather complex carbon, oxygen, and fluorine XPS peak analysis, and the character of the valence bands. An improved bias referencing method, based on ARXPS, is also demonstrated for evaluating specimen charging effects. It was found that the polymer molecule tends to resist the atomic oxygen attack by reorienting itself, so that the most electronegative CF3 groups are facing the incoming hyperthermal oxygen atoms. The implications of these findings to ground-based laboratory studies are discussed.

  3. Soft X-Ray Exposure Testing of FEP Teflon for the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    deGroh, Kim K.

    1998-01-01

    The FEP Teflon (DuPont) multilayer insulation (MLI) thermal-control blanket material on the Hubble Space Telescope is degrading in the space environment. During the first Hubble servicing mission in 1993, after 3.6 years in low Earth orbit, aluminized and silvered FEP Teflon MLI thermal-control blanket materials were retrieved. These materials have been jointly analyzed by the NASA Lewis Research Center and the NASA Goddard Space Flight Center for degradation induced in the space environment (ref. 1). Solar-facing blanket materials were found to be embrittled with through-the-thickness cracking in the 5-mil FEP. During the second Hubble servicing mission in 1997, astronauts noticed that several blankets had large areas with tears. The torn FEP was curled up in some areas, exposing the underlying materials to the space environment. This tearing problem, and the associated curling up of torn areas, could lead to over-heating of the telescope and to particulate contamination. A Hubble Space Telescope MLI Failure Review Board was assembled by Goddard to investigate and identify the degradation mechanism of the FEP, to identify and characterize replacement materials, and to estimate the extent of damage at the time of the third servicing mission in 1999. A small piece of FEP retrieved during the second servicing mission is being evaluated by this failure review board along with materials from the first servicing mission. Since the first servicing mission, and as part of the failure review board, Lewis has been exposing FEP to soft x-rays to help determine the damage mechanisms of FEP in the space environment. Soft x-rays, which can penetrate into the bulk of FEP, are generated during solar flares and appear to be contributing to the degradation of the Hubble MLI.

  4. Europium- and lithium-doped yttrium oxide nanocrystals that provide a linear emissive response with X-ray radiation exposure.

    PubMed

    Stanton, Ian N; Belley, Matthew D; Nguyen, Giao; Rodrigues, Anna; Li, Yifan; Kirsch, David G; Yoshizumi, Terry T; Therien, Michael J

    2014-05-21

    Eu- and Li-doped yttrium oxide nanocrystals [Y2-xO3; Eux, Liy], in which Eu and Li dopant ion concentrations were systematically varied, were developed and characterized (TEM, XRD, Raman spectroscopic, UV-excited lifetime, and ICP-AES data) in order to define the most emissive compositions under specific X-ray excitation conditions. These optimized [Y2-xO3; Eux, Liy] compositions display scintillation responses that: (i) correlate linearly with incident radiation exposure at X-ray energies spanning from 40-220 kVp, and (ii) manifest no evidence of scintillation intensity saturation at the highest evaluated radiation exposures [up to 4 Roentgen per second]. For the most emissive nanoscale scintillator composition, [Y1.9O3; Eu0.1, Li0.16], excitation energies of 40, 120, and 220 kVp were chosen to probe the dependence of the integrated emission intensity upon X-ray exposure-rate in energy regimes having different mass-attenuation coefficients and where either the photoelectric or the Compton effect governs the scintillation mechanism. These experiments demonstrate for the first time for that for comparable radiation exposures, when the scintillation mechanism is governed by the photoelectric effect and a comparably larger mass-attenuation coefficient (120 kVp excitation), greater integrated emission intensities are recorded relative to excitation energies where the Compton effect regulates scintillation (220 kVp) in nanoscale [Y2-xO3; Eux] crystals. Nanoscale [Y1.9O3; Eu0.1, Li0.16] (70 ± 20 nm) was further exploited as a detector material in a prototype fiber-optic radiation sensor. The scintillation intensity from the [Y1.9O3; Eu0.1, Li0.16]-modified, 400 μm sized optical fiber tip, recorded using a CCD-photodetector and integrated over the 605-617 nm wavelength domain, was correlated with radiation exposure using a Precision XRAD 225Cx small-animal image guided radiation therapy (IGRT) system. For both 80 and 225 kVp energies, this radiotransparent device

  5. Surface Evaluation by X-Ray Photoelectron Spectroscopy of High Performance Polyimide Foams After Exposure to Oxygen Plasma

    NASA Technical Reports Server (NTRS)

    Melendez, Orlando; Hampton, Michael D.; Williams, Martha K.; Brown, Sylvia F.; Nelson, Gordon L.; Weiser, Erik S.

    2002-01-01

    Aromatic polyimides have been attractive in the aerospace and electronics industries for applications such as cryogenic insulation, flame retardant panels and structural subcomponents. Newer to the arena of polyimides is the synthesis of polyimide foams and their applications. In the present work, three different, closely related, polyimide foams developed by NASA Langley Research Center (LaRC) are studied by X-ray Photoelectron Spectroscopy (XPS) after exposure to radio frequency generated Oxygen Plasma. Although polyimide films exposure to atomic oxygen and plasma have been studied previously and reported, the data relate to films and not foams. Foams have much more surface area and thus present new information to be explored. Understanding degradation mechanisms and properties versus structure, foam versus solid is of interest and fundamental to the application and protection of foams exposed to atomic oxygen in Low Earth Orbit (LEO).

  6. Maintaining radiation exposures as low as reasonably achievable (ALARA) for dental personnel operating portable hand-held x-ray equipment.

    PubMed

    McGiff, Thomas J; Danforth, Robert A; Herschaft, Edward E

    2012-08-01

    Clinical experience indicates that newly available portable hand-held x-ray units provide advantages compared to traditional fixed properly installed and operated x-ray units in dental radiography. However, concern that hand-held x-ray units produce higher operator doses than fixed x-ray units has caused regulatory agencies to mandate requirements for use of hand-held units that go beyond those recommended by the manufacturer and can discourage the use of this technology. To assess the need for additional requirements, a hand-held x-ray unit and a pair of manikins were used to measure the dose to a simulated operator under two conditions: exposures made according to the manufacturer's recommendations and exposures made according to manufacturer's recommendation except for the removal of the x-ray unit's protective backscatter shield. Dose to the simulated operator was determined using an array of personal dosimeters and a pair of pressurized ion chambers. The results indicate that the dose to an operator of this equipment will be less than 0.6 mSv y⁻¹ if the device is used according to the manufacturer's recommendations. This suggests that doses to properly trained operators of well-designed, hand-held dental x-ray units will be below 1.0 mSv y⁻¹ (2% of the annual occupational dose limit) even if additional no additional operational requirements are established by regulatory agencies. This level of annual dose is similar to those reported as typical dental personnel using fixed x-ray units and appears to satisfy the ALARA principal for this class of occupational exposures.

  7. Cross calibration of AGFA-D7 x-ray film against direct exposure film from 2 to 8.5 keV using laser generated x-rays

    SciTech Connect

    Kyrala, George A.

    2006-05-15

    Direct exposure film (DEF) is being discontinued. DEF film has been the workhorse in inertial confinement fusion (ICF) research and is used to record x-ray images and spectra. A previous search for a replacement [K. M. Chandler et al., Rev. Sci. Instrum. 76, 113111 (2005)] did not consider AGFA film. We present comparisons using the results of measurements using AGFA-D7 film, XAR, TMG, and Biomax-MS films in the same spectrometer recording a gold spectrum in the 2-4 keV range and the iron spectrum in the 5-8.5 keV range. AGFA film was found to have some unique properties useful in x-ray spectroscopy and imaging, especially when signal strength is not a concern.

  8. Cross calibration of AGFA-D7 x-ray film against direct exposure film from 2 to 8.5 keV using laser generated x-rays

    NASA Astrophysics Data System (ADS)

    Kyrala, George A.

    2006-05-01

    Direct exposure film (DEF) is being discontinued. DEF film has been the workhorse in inertial confinement fusion (ICF) research and is used to record x-ray images and spectra. A previous search for a replacement [K. M. Chandler et al., Rev. Sci. Instrum. 76, 113111 (2005)] did not consider AGFA film. We present comparisons using the results of measurements using AGFA-D7 film, XAR, TMG, and Biomax-MS films in the same spectrometer recording a gold spectrum in the 2-4keV range and the iron spectrum in the 5-8.5keV range. AGFA film was found to have some unique properties useful in x-ray spectroscopy and imaging, especially when signal strength is not a concern.

  9. Diagnostic X-rays and risk of childhood leukaemia

    PubMed Central

    Bartley, Karen; Metayer, Catherine; Selvin, Steve; Ducore, Jonathan; Buffler, Patricia

    2010-01-01

    Background The association between diagnostic X-ray exposures early in life and increased risk of childhood leukaemia remains unclear. Methods This case–control study included children aged 0–14 years diagnosed with acute lymphoid leukaemia (ALL, n = 711) or acute myeloid leukaemia (AML, n = 116) from 1995 to 2008. Controls were randomly selected from the California birth registry and individually matched to cases with respect to date of birth, sex, Hispanic ethnicity and maternal race. Conditional logistic regression analyses were performed to assess whether ALL or AML was associated with self-reported child’s X-rays after birth (post-natal), including number of X-rays, region of the body X-rayed and age at first X-ray, as well as maternal X-rays before and during pregnancy (preconception and prenatal). Results After excluding X-rays in the year prior to diagnosis (reference date for matched controls), risk of ALL was elevated in children exposed to three or more post-natal X-rays [odds ratio (OR) = 1.85, 95% confidence interval (CI) 1.12–2.79]. For B-cell ALL specifically, any exposure (one or more X-rays) conferred increased risk (OR = 1.40, 95% CI 1.06–1.86). Region of the body exposed was not an independent risk factor in multivariable analyses. No associations were observed between number of post-natal X-rays and AML (OR = 1.05, 95% CI 0.90–1.22) or T-cell ALL (OR = 0.84, 95% CI 0.59–1.19). Prevalence of exposure to prenatal and preconception X-rays was low, and no associations with ALL or AML were observed. Conclusions The results suggest that exposure to post-natal diagnostic X-rays is associated with increased risk of childhood ALL, specifically B-cell ALL, but not AML or T-cell ALL. Given the imprecise measures of self-reported X-ray exposure, the results of this analysis should be interpreted with caution and warrant further investigation. PMID:20889538

  10. Evaluation of a novel portable x-ray fluorescence screening tool for detection of arsenic exposure.

    PubMed

    McIver, David J; VanLeeuwen, John A; Knafla, Anthony L; Campbell, Jillian A; Alexander, Kevin M; Gherase, Mihai R; Guernsey, Judith R; Fleming, David E B

    2015-12-01

    A new portable x-ray fluorescence (XRF) screening tool was evaluated for its effectiveness in arsenic (As) quantification in human finger and toe nails ([Formula: see text]). Nail samples were measured for total As concentration by XRF and inductively coupled plasma-mass spectrometry (ICP-MS). Using concordance correlation coefficient (CCC), kappa, diagnostic sensitivity (Sn) and specificity (Sp), and linear regression analyses, the concentration of As measured by XRF was compared to ICP-MS. The CCC peaked for scaled values of fingernail samples, at 0.424 (95% CI: 0.065-0.784). The largest kappa value, 0.400 (95% CI:  -0.282-1.000), was found at a 1.3 μg g(-1) cut-off concentration, for fingernails only, and the largest kappa at a clinically relevant cut-off concentration of 1.0 μg g(-1) was 0.237 (95% CI:  -0.068-0.543), again in fingernails. Analyses generally showed excellent XRF Sn (up to 100%, 95% CI: 48-100%), but low Sp (up to 30% for the same analysis, 95% CI: 14-50%). Portable XRF shows some potential for use as a screening tool with fingernail samples. The difference between XRF and ICP-MS measurements decreased as sample mass increased to 30 mg. While this novel method of As detection in nails has shown relatively high agreement in some scenarios, this portable XRF is not currently considered suitable as a substitute for ICP-MS.

  11. Inter-observer agreement in interpreting chest X-rays on children with acute lower respiratory tract infections and concurrent wheezing.

    PubMed

    Bada, Carlos; Carreazo, Nilton Yhuri; Chalco, Juan Pablo; Huicho, Luis

    2007-05-03

    Many children with acute lower respiratory tract infections (ALRI) present to the emergency ward with concurrent wheezing. A chest x-ray is often requested to rule out pneumonia. We assessed inter-observer agreement in interpreting x-rays on such children. DESIGNS AND SETTING: Prospective consecutive case study at Instituto de Salud del Niño, Lima, Peru. Chest x-rays were obtained from eligible children younger than two years old with ALRI and concurrent wheezing who were seen in the emergency ward of a nationwide pediatric referral hospital. The x-rays were read independently by three different pediatric residents who were aware only that the children had a respiratory infection. All the children had received inhaled beta-adrenergic agonists before undergoing chest x-rays. Lobar and complicated pneumonia cases were excluded from the study. Two hundred x-rays were read. The overall kappa index was 0.2. The highest individual kappa values for specific x-ray findings ranged from 0.26 to 0.34 for rib horizontalization and from 0.14 to 0.31 for alveolar infiltrate. Inter-observer variation was intermediate for alveolar infiltrate (kappa 0.14 to 0.21) and for air bronchogram (kappa 0.13 to 0.23). Reinforcement of the bronchovascular network (kappa 0.10 to 0.16) and air trapping (kappa 0.05 to 0.20) had the lowest agreement. There was poor inter-observer agreement for chest x-ray interpretation on children with ALRI and concurrent wheezing seen at the emergency ward. This may preclude reliable diagnosing of pneumonia in settings where residents make management decisions regarding sick children. The effects of training on inter-observer variation need further studies.

  12. Validation of a clinical decision rule: chest X-ray in patients with chest pain and possible acute coronary syndrome.

    PubMed

    Goldschlager, Romi; Roth, Hedley; Solomon, Jarryd; Robson, Scott; Green, Jessica; Green, Sarah; Spanger, Manfred; Gunn, Robyn; Cameron, Peter

    2014-08-01

    Current literature suggests that a large proportion of chest X-rays (CXRs) performed in emergency department (ED) patients with chest pain and suspected acute coronary syndrome (ACS) are unnecessary. The Canadian ACS Guidelines aim to guide clinicians in the appropriate use of CXR within this patient population. This study determined the prevalence of clinically significant CXR abnormalities and assessed the utility of the guidelines in a population of ED patients with chest pain and suspected ACS. Included in the study were participants over the age of 18 who presented to an Australian metropolitan ED, over a 1-year period, with a primary complaint of chest pain and who had a CXR and troponin level ordered in the ED (N = 760). We retrospectively compared their radiographic findings with their recommendations for CXR according to the ACS Guidelines. We found that 12 % of the participants had a clinically significant chest X-ray. The guidelines had a sensitivity of 80 % (95 % CI 0.70-0.87) and specificity of 50 % (95 % CI 0.47-0.54). The positive predictive value was 18 % (95 % CI 0.15-0.22) with a 95 % negative predictive value (95 % CI 0.92-0.97). Had the ACS guidelines been applied to our patient population, the number of CXR performed would have been reduced by 47 %. This study suggests that the ACS Guidelines has the potential to reduce the numbers of unnecessary CXR performed in ED patients. However, this would come at the expense of missing a minority of significant CXR abnormalities.

  13. [The development of the ionization chamber and the researching of its characteristics for automatic exposure controlling in the X-ray diagnosis machine].

    PubMed

    Weng, P; Liu, S; Wang, H; Cao, Y; Wang, X; Li, Y

    1999-01-01

    An ionization chamber for automatic exposure controlling used in X ray diagnosis machine was developped, and its characteristics were measured and researched. The electrodes of measuring field were made of carbon, such couldn't leave it's imaging on the film. In order to increase the ionization efficiency and decrease the thickness and electric capacity between electrodes, the chamber was constructed in multilayers. The chamber we developed can be fixed in different x ray machines convenientlly, there is a fine linearity between it's signal output and the exposures, the beam quality response is uniform and output-timing response is also good.

  14. Analysis of Flow Cytometry DNA Damage Response Protein Activation Kinetics Following X-rays and High Energy Iron Nuclei Exposure

    SciTech Connect

    Universities Space Research Association; Chappell, Lori J.; Whalen, Mary K.; Gurai, Sheena; Ponomarev, Artem; Cucinotta, Francis A.; Pluth, Janice M.

    2010-12-15

    We developed a mathematical method to analyze flow cytometry data to describe the kinetics of {gamma}H2AX and pATF2 phosphorylations ensuing various qualities of low dose radiation in normal human fibroblast cells. Previously reported flow cytometry kinetic results for these DSB repair phospho-proteins revealed that distributions of intensity were highly skewed, severely limiting the detection of differences in the very low dose range. Distributional analysis reveals significant differences between control and low dose samples when distributions are compared using the Kolmogorov-Smirnov test. Radiation quality differences are found in the distribution shapes and when a nonlinear model is used to relate dose and time to the decay of the mean ratio of phosphoprotein intensities of irradiated samples to controls. We analyzed cell cycle phase and radiation quality dependent characteristic repair times and residual phospho-protein levels with these methods. Characteristic repair times for {gamma}H2AX were higher following Fe nuclei as compared to X-rays in G1 cells (4.5 {+-} 0.46 h vs 3.26 {+-} 0.76 h, respectively), and in S/G2 cells (5.51 {+-} 2.94 h vs 2.87 {+-} 0.45 h, respectively). The RBE in G1 cells for Fe nuclei relative to X-rays for {gamma}H2AX was 2.05 {+-} 0.61 and 5.02 {+-} 3.47, at 2 h and 24-h postirradiation, respectively. For pATF2, a saturation effect is observed with reduced expression at high doses, especially for Fe nuclei, with much slower characteristic repair times (>7 h) compared to X-rays. RBEs for pATF2 were 0.66 {+-} 0.13 and 1.66 {+-} 0.46 at 2 h and 24 h, respectively. Significant differences in {gamma}H2AX and pATF2 levels comparing irradiated samples to control were noted even at the lowest dose analyzed (0.05 Gy) using these methods of analysis. These results reveal that mathematical models can be applied to flow cytometry data to uncover important and subtle differences following exposure to various qualities of low dose radiation.

  15. Effect of X-ray and ethylnitrosourea exposures separated by 24 h on specific-locus mutation frequency in mouse stem-cell spermatogonia.

    PubMed

    Russell, W L; Carpenter, D A; Hitotsumachi, S

    1988-04-01

    Specific-locus mutation frequencies in mouse stem-cell spermatogonia were determined in 3 experiments in which mature male mice were exposed to 100,m 300, or 500 R of X-rays followed, 24 h later, by intraperitoneal injection of 100 mg/kg of ethylnitrosourea (ENU). The purpose was to find out if the mutation frequencies would be augmented over those expected on the basis of additivity of the effects of the separate treatments. Such augmentation had been observed in earlier work in which exposure to 100 or 500 R of X-rays was followed 24 h later by a second exposure of 500 R. No augmentation was observed for X-rays followed by ENU. The mutation frequencies in all 3 experiments actually fell below those expected on the basis of additivity, although the reductions were not statistically significant.

  16. The effect of embryonic and fetal exposure to x-ray, microwaves, and ultrasound: Counseling the pregnant and nonpregnant patient about these risks

    SciTech Connect

    Brent, R.L. )

    1989-10-01

    The term radiation evokes emotional responses both from lay persons and from professionals. Many spokespersons are unfamiliar with radiation biology or the quantitative nature of the risks. Frequently, microwave, ultrasound, and ionizing radiation risks are confused. Although it is impossible to prove no risk for any environmental hazard, it appears that exposure to microwave radiation below the maximal permissible levels present no measurable risk to the embryo. Ultrasound exposure from diagnostic ultrasonographic-imaging equipment also is quite innocuous. It is true that continued surveillance and research into potential risks of these low-level exposures should continue; however, at present ultrasound not only improves obstetric care, but also reduces the necessity of diagnostic x-ray procedures. In the field of ionizing radiation, we have a better comprehension of the biologic effects and the quantitative maximum risks than for any other environmental hazard. Although the animal and human data support the conclusion that no increases in the incidence of gross congenital malformations, IUGR, or abortion will occur with exposures less than 5 rad, that does not mean that there are definitely no risks to the embryo exposed to lower doses of radiation, Whether there exists a linear or exponential dose-response relationship or a threshold exposure for genetic, carcinogenic, cell-depleting, and life-shortening effects has not been determined. It is obvious that the risks of 1-rad (.10Gy) or 5-rad (.05Gy) acute exposure are far below the spontaneous risks of the developing embryo because 15% of human embryos abort, 2.7% to 3.0% of human embryos have major malformations, 4% have intrauterine growth retardation, and 8% to 10% have early- or late-stage onset genetic disease. 92 references.

  17. Pathology of breast cancer in women irradiated for acute postpartum mastitis. [X rays

    SciTech Connect

    Dvoretsky, P.M.; Woodard, E.; Bonfiglio, T.A.; Hempelmann, L.H.; Morse, I.P.

    1980-11-15

    The gross and microscopic pathology of breast cancers in women irradiated for acute postpartum mastitis was compared to the breast cancers found in the sisters of the irradiated women. In considering the lesions in the two populations, the size, location, histologic type, histologic grade, inflammatory response, lymphatic and blood vascular invasion, nipple involvement, axillary lymph node metastases, and menopausal status at the time of diagnosis were statistically indistinguishable. The only parameter that was different in the two populations was the desmoplastic response to the malignant lesion. The control population had more marked fibrosis within the cancers compared with the irradiated women.

  18. Bone X-Ray (Radiography)

    MedlinePlus

    ... have very controlled x-ray beams and dose control methods to minimize stray (scatter) radiation. This ensures that those parts of a patient's body not being imaged receive minimal radiation exposure. top ...

  19. Abdomen X-Ray (Radiography)

    MedlinePlus

    ... have very controlled x-ray beams and dose control methods to minimize stray (scatter) radiation. This ensures that those parts of a patient's body not being imaged receive minimal radiation exposure. top ...

  20. Characterisation of a setup for mixed beam exposures of cells to 241Am alpha particles and X-rays.

    PubMed

    Staaf, Elina; Brehwens, Karl; Haghdoost, Siamak; Pachnerová-Brabcová, Katerina; Czub, Joanna; Braziewicz, Janusz; Nievaart, Sander; Wojcik, Andrzej

    2012-09-01

    Exposure of humans to mixed fields of high- and low-linear energy transfer (LET) radiation occurs in many situations-for example, in urban areas with high levels of indoor radon as well as background gamma radiation, during airplane flights or certain forms of radiation therapy. From the perspective of health risk associated with exposure to mixed fields, it is important to understand the interactions between different radiation types. In most cellular investigations on mixed beams, two types of irradiations have been applied sequentially. Simultaneous irradiation is the desirable scenario but requires a dedicated irradiation facility. The authors have constructed a facility where cells can be simultaneously exposed to (241)Am alpha particles and 190-kV X-rays at 37°C. This study presents the technical details and the dosimetry of the setup, as well as validates the performance of the setup for clonogenic survival in AA8 Chinese hamster ovary cells. No significant synergistic effect was observed. The relative biological effectiveness of the alpha particles was 2.56 for 37 % and 1.90 for 10 % clonogenic survival.

  1. Joint x-ray

    MedlinePlus

    X-ray - joint; Arthrography; Arthrogram ... x-ray technologist will help you position the joint to be x-rayed on the table. Once in place, pictures are taken. The joint may be moved into other positions for more ...

  2. Chest X Ray?

    MedlinePlus

    ... this page from the NHLBI on Twitter. Chest X Ray A chest x ray is a fast and painless imaging test that ... tissue scarring, called fibrosis. Doctors may use chest x rays to see how well certain treatments are working ...

  3. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1990-01-01

    The annual progress report on Cosmic X Ray Physics is presented. Topics studied include: the soft x ray background, proportional counter and filter calibrations, the new sounding rocket payload: X Ray Calorimeter, and theoretical studies.

  4. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1991-01-01

    The annual progress report on Cosmic X Ray Physics for the period 1 Jan. to 31 Dec. 1990 is presented. Topics studied include: soft x ray background, new sounding rocket payload: x ray calorimeter, and theoretical studies.

  5. Skull x-ray

    MedlinePlus

    X-ray - head; X-ray - skull; Skull radiography; Head x-ray ... Chernecky CC, Berger BJ. Radiography of skull, chest, and cervical spine - diagnostic. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures . 6th ed. ...

  6. Chest X-Ray

    MedlinePlus

    ... by Image/Video Gallery Your radiologist explains chest x-ray. Transcript Welcome to Radiology Info dot org! Hello, ... you about chest radiography also known as chest x-rays. Chest x-rays are the most commonly performed ...

  7. Induction of DNA DSB and its rejoining in clamped and non-clamped tumours after exposure to carbon ion beams in comparison to X rays.

    PubMed

    Hirayama, R; Uzawa, A; Matsumoto, Y; Noguchi, M; Kase, Y; Takase, N; Ito, A; Koike, S; Ando, K; Okayasu, R; Furusawa, Y

    2011-02-01

    We studied double-strand breaks (DSB) induction and rejoining in clamped and non-clamped transplanted tumours in mice leg after exposure to 80 keV µm(-1) carbon ions and X rays. The yields of DSB in the tumours were analysed by a static-field gel electrophoresis. The OER of DSB after X rays was 1.68±0.31, and this value was not changed after 1 h rejoining time (1.40±0.26). These damages in oxygenated conditions were rejoined 60-70% within 1 h in situ. No difference was found between the exposure to X rays and carbon ions for the induction and rejoining of DSB. Thus, the values of OER and rejoined fraction after exposure to carbon ions were similar to those after X rays, and the calculated relative biological effectivenesses of carbon ion were around 1 under both oxygen conditions. The yields of DSB in vivo depend on exposure doses, oxygen conditions and rejoining time, but not on the types of radiation quality.

  8. Acute effects of delayed reperfusion following myocardial infarction: a 3D x-ray imaging analysis

    NASA Astrophysics Data System (ADS)

    Simari, Robert D.; Bell, M. R.; Pao, Y. C.; Gersh, B. J.; Ritman, Erik L.

    1996-04-01

    Clinical and experimental data suggest that delayed reperfusion of the infarct related artery may limit infarct expansion without increasing myocardial salvage. In order to assess the potential mechanisms involved, an acute closed chest canine model of myocardial infarction and delayed reperfusion was studied. Nineteen dogs underwent 3D computed tomography in the Dynamic Spatial Reconstructor (a fast, volume imaging, CT scanner) at baseline and three and four hours later to estimate left ventricular chamber volumes, global distensibility and regional myocardial stiffness. A control group was scanned without intervention. An occlusion group underwent four hours of coronary artery occlusion. A reperfusion group underwent three hours of coronary artery occlusion followed by one hour of reperfusion. Similar infarct sizes were seen in the occlusion and reperfusion groups. Globally reperfusion was associated with increased left ventricular end diastolic pressure and prolongation of global relaxation. Regionally reperfusion was associated with increased myocardial stiffness, intramyocardial blood volume and wall thickness within the infarct zone relative to the not reperfused myocardium.

  9. Selective brain responses to acute and chronic low-dose X-ray irradiation in males and females.

    PubMed

    Silasi, Greg; Diaz-Heijtz, Rochellys; Besplug, Jill; Rodriguez-Juarez, Rocio; Titov, Viktor; Kolb, Bryan; Kovalchuk, Olga

    2004-12-24

    Radiation exposure is known to have profound effects on the brain, leading to precursor cell dysfunction and debilitating cognitive declines [Nat. Med. 8 (2002) 955]. Although a plethora of data exist on the effects of high radiation doses, the effects of low-dose irradiation, such as ones received during repetitive diagnostic and therapeutic exposures, are still under-investigated [Am. J. Otolaryngol. 23 (2002) 215; Proc. Natl. Acad. Sci. USA 97 (2000) 889; Curr. Opin. Neurol. 16 (2003) 129]. Furthermore, most studies of the biological effects of ionizing radiation have been performed using a single acute dose, while clinically and environmentally relevant exposures occur predominantly under chronic/repetitive conditions. Here, we have used a mouse model to compare the effects of chronic/repetitive and acute low-dose radiation (LDR) exposure (0.5Gy) to ionizing radiation on the brain in vivo. We examined the LDR effects on p42/44 MAPK (ERK1/ERK2), CaMKII, and AKT signaling-the interconnected pathways that have been previously shown to be crucial for neuronal survival upon irradiation. We report perturbations in ERK1/2, AKT, and CREB upon acute and chronic/repetitive low-dose exposure in the hippocampus and frontal cortex of mice. These studies were paralleled by the analysis of radiation effects on neurogenesis and cellular proliferation. Repetitive exposure had a much more pronounced effect on cellular signaling and neurogenesis than acute exposure. These results suggest that studies of single acute exposures might be limited in terms of their predictive value. We also present the first evidence of sex differences in radiation-induced signaling in the hippocampus and frontal cortex. We show the role of estrogens in brain radiation responses and discuss the implications of the observed changes.

  10. Developable images produced by x-rays using the nickel-hypophosphite system. 2: Exposure and development parameters for sodium hypophosphite

    NASA Technical Reports Server (NTRS)

    May, C. E.; Philipp, W. H.; Marsik, S. J.

    1972-01-01

    Crystalline sodium hypophosphite was X-irradiated and then treated with an ammoniacal nickel hypophosphite solution. Treatment resulted in the precipitation of nickel metal. The yield of nickel metal varied directly with particle size, sample weight, X-ray voltage, target current, exposure time, and development time. These findings show the process to be potentially useful in X-ray type photography. The half-life for the latent image species was found to be relatively short; but this is not critical in most X-ray photography applications. Furthermore, the work can be interpreted on the basis that a hydrogen atom is involved in the mechanism and indicates that the autocatalytic development step may be self-poisoning.

  11. Estimates of Average Glandular Dose with Auto-modes of X-ray Exposures in Digital Breast Tomosynthesis.

    PubMed

    Kamal, Izdihar; Chelliah, Kanaga K; Mustafa, Nawal

    2015-05-01

    The aim of this research was to examine the average glandular dose (AGD) of radiation among different breast compositions of glandular and adipose tissue with auto-modes of exposure factor selection in digital breast tomosynthesis. This experimental study was carried out in the National Cancer Society, Kuala Lumpur, Malaysia, between February 2012 and February 2013 using a tomosynthesis digital mammography X-ray machine. The entrance surface air kerma and the half-value layer were determined using a 100H thermoluminescent dosimeter on 50% glandular and 50% adipose tissue (50/50) and 20% glandular and 80% adipose tissue (20/80) commercially available breast phantoms (Computerized Imaging Reference Systems, Inc., Norfolk, Virginia, USA) with auto-time, auto-filter and auto-kilovolt modes. The lowest AGD for the 20/80 phantom with auto-time was 2.28 milliGray (mGy) for two dimension (2D) and 2.48 mGy for three dimensional (3D) images. The lowest AGD for the 50/50 phantom with auto-time was 0.97 mGy for 2D and 1.0 mGy for 3D. The AGD values for both phantoms were lower against a high kilovolt peak and the use of auto-filter mode was more practical for quick acquisition while limiting the probability of operator error.

  12. Estimates of Average Glandular Dose with Auto-modes of X-ray Exposures in Digital Breast Tomosynthesis

    PubMed Central

    Kamal, Izdihar; Chelliah, Kanaga K.; Mustafa, Nawal

    2015-01-01

    Objectives: The aim of this research was to examine the average glandular dose (AGD) of radiation among different breast compositions of glandular and adipose tissue with auto-modes of exposure factor selection in digital breast tomosynthesis. Methods: This experimental study was carried out in the National Cancer Society, Kuala Lumpur, Malaysia, between February 2012 and February 2013 using a tomosynthesis digital mammography X-ray machine. The entrance surface air kerma and the half-value layer were determined using a 100H thermoluminescent dosimeter on 50% glandular and 50% adipose tissue (50/50) and 20% glandular and 80% adipose tissue (20/80) commercially available breast phantoms (Computerized Imaging Reference Systems, Inc., Norfolk, Virginia, USA) with auto-time, auto-filter and auto-kilovolt modes. Results: The lowest AGD for the 20/80 phantom with auto-time was 2.28 milliGray (mGy) for two dimension (2D) and 2.48 mGy for three dimensional (3D) images. The lowest AGD for the 50/50 phantom with auto-time was 0.97 mGy for 2D and 1.0 mGy for 3D. Conclusion: The AGD values for both phantoms were lower against a high kilovolt peak and the use of auto-filter mode was more practical for quick acquisition while limiting the probability of operator error. PMID:26052465

  13. Nested Case-control Study of Occupational Radiation Exposure and Breast and Esophagus Cancer Risk among Medical Diagnostic X Ray Workers in Jiangsu of China.

    PubMed

    Wang, Fu-Ru; Fang, Qiao-Qiao; Tang, Wei-Ming; Xu, Xiao-San; Mahapatra, Tanmay; Mahapatra, Sanchita; Liu, Yu-Fei; Yu, Ning-Le; Sun, Quan-Fu

    2015-01-01

    Medical diagnostic X-ray workers are one occupational group that expose to the long-term low-dose external radiation over their working lifetime, and they may under risk of different cancers. This study aims to determine the relationship between the occupational X-ray radiation exposure and cancer risk among these workers in Jiangsu, China. We conducted Nested case-control study to investigate the occupational X-ray radiation exposure and cancer risk. Data were collected through self-administered questionnaire, which includes but not limits to demographic data, personal behaviors and family history of cancer. Retrospective dose reconstruction was conducted to estimate the cumulative doses of the x-ray workers. Inferential statistics, t-test and 2 tests were used to compare the differences between each group. We used the logistic regression model to calculate the odds ratio (OR) and 95% confidence interval (CI) of cancer by adjusting the age, gender. All 34 breast cancer cases and 45 esophageal cancer cases that detected in a cohort conducted among health workers between 1950~2011 were included in this presented study, and 158 cancer-free controls were selected by frequency-matched (1:2). Our study found that the occupational radiation exposure was associated with a significantly increased cancer risk compared with the control, especially in breast cancer and esophageal cancer (adjusted OR=2.90, 95% CI: 1.19-7.04 for breast cancer; OR=4.19, 95% CI: 1.87-9.38 for esophageal cancer, and OR=3.43, 95% CI: 1.92-6.12 for total cancer, respectively). The occupational X-ray radiation exposure was associated with increasing cancer risk, which indicates that proper intervention and prevention strategies may be needed in order to bring down the occupational cancer risk.

  14. X-ray imaging for palaeontology.

    PubMed

    Hohenstein, P

    2004-05-01

    Few may be aware that X-ray imaging is used in palaeontology and has been used since as early as 1896. The X-raying, preparation and exposure of Hunsrück slate fossils are described. Hospital X-ray machines are used by the author in his work. An X-ray is vital to provide evidence that preparation of a slate is worthwhile as well as to facilitate preparation even if there is little external sign of what lies within. The beauty of the X-ray exposure is an added bonus.

  15. X-ray transmissive debris shield

    DOEpatents

    Spielman, Rick B.

    1996-01-01

    An X-ray debris shield for use in X-ray lithography that is comprised of an X-ray window having a layer of low density foam exhibits increased longevity without a substantial increase in exposure time. The low density foam layer serves to absorb the debris emitted from the X-ray source and attenuate the shock to the window so as to reduce the chance of breakage. Because the foam is low density, the X-rays are hardly attenuated by the foam and thus the exposure time is not substantially increased.

  16. X-ray transmissive debris shield

    DOEpatents

    Spielman, R.B.

    1996-05-21

    An X-ray debris shield for use in X-ray lithography that is comprised of an X-ray window having a layer of low density foam exhibits increased longevity without a substantial increase in exposure time. The low density foam layer serves to absorb the debris emitted from the X-ray source and attenuate the shock to the window so as to reduce the chance of breakage. Because the foam is low density, the X-rays are hardly attenuated by the foam and thus the exposure time is not substantially increased.

  17. Aberrant cell divisions in root meristeme of maize following exposure to X-rays low doses compared to similar effects of 50 Hz electromagnetic exposure

    NASA Astrophysics Data System (ADS)

    Focea, R.; Capraru, G.; Racuciu, M.; Creanga, D.; Luchian, T.

    2012-04-01

    The response of maize to radiation exposure was investigated by two cytogenetic methods considering the importance of the geno-toxic effect for environmental and agricultural purposes. Uniform genophond seeds, freshly germinated, were exposed to relatively low radiation doses using a radiotherapy X-ray applicator from a hospital irradiation device and to a 50 Hz electromagnetic field with about 10 mT magnetic induction (generated within laboratory assembled electromagnetic coils). Radicular meristeme tissue aliquots were prevailed for cytogenetic investigation based on microscopic observations and cell counting. Microscope slides were prepared following a specific procedure (squash technique and Feulgen method based on modified Carr reactive coloration). Mitotic index as well as chromosomal aberration percentage were calculated for more than 30,000 cells taken into account. From a qualitative viewpoint, chromosomal aberrations such as interchromatidian bridges, lagging and expelled chromosomes and multipolar divisions were evidenced - no distinct situation for either ionizing radiation or electromagnetic field being identified. The main quantitative difference consisted in the increased mitotic index for electromagnetic exposure increased times compared with the diminished mitotic index in the case of low X-ray doses.

  18. Radiation–Induced Signaling Results in Mitochondrial Impairment in Mouse Heart at 4 Weeks after Exposure to X-Rays

    PubMed Central

    Barjaktarovic, Zarko; Schmaltz, Dominik; Shyla, Alena; Azimzadeh, Omid; Schulz, Sabine; Haagen, Julia; Dörr, Wolfgang; Sarioglu, Hakan; Schäfer, Alexander; Atkinson, Michael J.; Zischka, Hans; Tapio, Soile

    2011-01-01

    Backround Radiation therapy treatment of breast cancer, Hodgkin's disease or childhood cancers expose the heart to high local radiation doses, causing an increased risk of cardiovascular disease in the survivors decades after the treatment. The mechanisms that underlie the radiation damage remain poorly understood so far. Previous data show that impairment of mitochondrial oxidative metabolism is directly linked to the development of cardiovascular disease. Methodology/Principal findings In this study, the radiation-induced in vivo effects on cardiac mitochondrial proteome and function were investigated. C57BL/6N mice were exposed to local irradiation of the heart with doses of 0.2 Gy or 2 Gy (X-ray, 200 kV) at the age of eight weeks, the control mice were sham-irradiated. After four weeks the cardiac mitochondria were isolated and tested for proteomic and functional alterations. Two complementary proteomics approaches using both peptide and protein quantification strategies showed radiation-induced deregulation of 25 proteins in total. Three main biological categories were affected: the oxidative phophorylation, the pyruvate metabolism, and the cytoskeletal structure. The mitochondria exposed to high-dose irradiation showed functional impairment reflected as partial deactivation of Complex I (32%) and Complex III (11%), decreased succinate-driven respiratory capacity (13%), increased level of reactive oxygen species and enhanced oxidation of mitochondrial proteins. The changes in the pyruvate metabolism and structural proteins were seen with both low and high radiation doses. Conclusion/Significance This is the first study showing the biological alterations in the murine heart mitochondria several weeks after the exposure to low- and high-dose of ionizing radiation. Our results show that doses, equivalent to a single dose in radiotherapy, cause long-lasting changes in mitochondrial oxidative metabolism and mitochondria-associated cytoskeleton. This prompts us to

  19. Radiation-induced signaling results in mitochondrial impairment in mouse heart at 4 weeks after exposure to X-rays.

    PubMed

    Barjaktarovic, Zarko; Schmaltz, Dominik; Shyla, Alena; Azimzadeh, Omid; Schulz, Sabine; Haagen, Julia; Dörr, Wolfgang; Sarioglu, Hakan; Schäfer, Alexander; Atkinson, Michael J; Zischka, Hans; Tapio, Soile

    2011-01-01

    Radiation therapy treatment of breast cancer, Hodgkin's disease or childhood cancers expose the heart to high local radiation doses, causing an increased risk of cardiovascular disease in the survivors decades after the treatment. The mechanisms that underlie the radiation damage remain poorly understood so far. Previous data show that impairment of mitochondrial oxidative metabolism is directly linked to the development of cardiovascular disease. In this study, the radiation-induced in vivo effects on cardiac mitochondrial proteome and function were investigated. C57BL/6N mice were exposed to local irradiation of the heart with doses of 0.2 Gy or 2 Gy (X-ray, 200 kV) at the age of eight weeks, the control mice were sham-irradiated. After four weeks the cardiac mitochondria were isolated and tested for proteomic and functional alterations. Two complementary proteomics approaches using both peptide and protein quantification strategies showed radiation-induced deregulation of 25 proteins in total. Three main biological categories were affected: the oxidative phophorylation, the pyruvate metabolism, and the cytoskeletal structure. The mitochondria exposed to high-dose irradiation showed functional impairment reflected as partial deactivation of Complex I (32%) and Complex III (11%), decreased succinate-driven respiratory capacity (13%), increased level of reactive oxygen species and enhanced oxidation of mitochondrial proteins. The changes in the pyruvate metabolism and structural proteins were seen with both low and high radiation doses. This is the first study showing the biological alterations in the murine heart mitochondria several weeks after the exposure to low- and high-dose of ionizing radiation. Our results show that doses, equivalent to a single dose in radiotherapy, cause long-lasting changes in mitochondrial oxidative metabolism and mitochondria-associated cytoskeleton. This prompts us to propose that these first pathological changes lead to an increased

  20. X-ray Sensitive Material

    DTIC Science & Technology

    2015-12-01

    The research resulted in a composite material that holds a quasi-permanent electric charge and rapidly discharges the electric charge upon X-ray...temperature extremes encountered during processing and potential application. (U) The result of these efforts was a composite material that would hold a...quasi-permanent electric charge and rapidly discharge the electric charge upon X-ray exposure. The composite material combined the properties of an

  1. Chest x-ray

    MedlinePlus

    Chest radiography; Serial chest x-ray; X-ray - chest ... You stand in front of the x-ray machine. You will be told to hold your breath when the x-ray is taken. Two images are usually taken. You will ...

  2. 4D synchrotron X-ray imaging to understand porosity development in shales during exposure to hydraulic fracturing fluid

    NASA Astrophysics Data System (ADS)

    Kiss, A. M.; Bargar, J.; Kohli, A. H.; Harrison, A. L.; Jew, A. D.; Lim, J. H.; Liu, Y.; Maher, K.; Zoback, M. D.; Brown, G. E.

    2016-12-01

    Unconventional (shale) reservoirs have emerged as the most important source of petroleum resources in the United States and represent a two-fold decrease in greenhouse gas emissions compared to coal. Despite recent progress, hydraulic fracturing operations present substantial technical, economic, and environmental challenges, including inefficient recovery, wastewater production and disposal, contaminant and greenhouse gas pollution, and induced seismicity. A relatively unexplored facet of hydraulic fracturing operations is the fluid-rock interface, where hydraulic fracturing fluid (HFF) contacts shale along faults and fractures. Widely used, water-based fracturing fluids contain oxidants and acid, which react strongly with shale minerals. Consequently, fluid injection and soaking induces a host of fluid-rock interactions, most notably the dissolution of carbonates and sulfides, producing enhanced or "secondary" porosity networks, as well as mineral precipitation. The competition between these mechanisms determines how HFF affects reactive surface area and permeability of the shale matrix. The resultant microstructural and chemical changes may also create capillary barriers that can trap hydrocarbons and water. A mechanistic understanding of the microstructure and chemistry of the shale-HFF interface is needed to design new methodologies and fracturing fluids. Shales were imaged using synchrotron micro-X-ray computed tomography before, during, and after exposure to HFF to characterize changes to the initial 3D structure. CT reconstructions reveal how the secondary porosity networks advance into the shale matrix. Shale samples span a range of lithologies from siliceous to calcareous to organic-rich. By testing shales of different lithologies, we have obtained insights into the mineralogic controls on secondary pore network development and the morphologies at the shale-HFF interface and the ultimate composition of produced water from different facies. These results

  3. Assessment of targeted and non-targeted responses in cells deficient in ATM function following exposure to low and high dose X-rays.

    PubMed

    Kiuru, Anne; Kämäräinen, Meerit; Heinävaara, Sirpa; Pylkäs, Katri; Chapman, Kim; Koivistoinen, Armi; Parviainen, Teuvo; Winqvist, Robert; Kadhim, Munira; Launonen, Virpi; Lindholm, Carita

    2014-01-01

    Radiation sensitivity at low and high dose exposure to X-rays was investigated by means of chromosomal aberration (CA) analysis in heterozygous ATM mutation carrier and A-T patient (biallelic ATM mutation) lymphoblastoid cell lines (LCLs). Targeted and non-targeted responses to acutely delivered irradiation were examined by applying a co-culture system that enables study of both directly irradiated cells and medium-mediated bystander effects in the same experimental setting. No indication of radiation hypersensitivity was observed at doses of 0.01 Gy or 0.1 Gy for the ATM mutation carrier LCL. The A-T patient cells also did not show low-dose response. There was significant increase in unstable CA yields for both ATM mutation carrier and A-T LCLs at 1 and 2 Gy, the A-T cells displaying more distinct dose dependency. Both chromosome and chromatid type aberrations were induced at an increased rate in the irradiated A-T cells, whereas for ATM carrier cells, only unstable chromosomal aberrations were increased above the level observed in the wild type cell line. No bystander effect could be demonstrated in any of the cell lines or doses applied. Characteristics typical for the A-T cell line were detected, i.e., high baseline frequency of CA that increased with dose. In addition, dose-dependent loss of cell viability was observed. In conclusion, CA analysis did not demonstrate low-dose (≤100 mGy) radiosensitivity in ATM mutation carrier cells or A-T patient cells. However, both cell lines showed increased radiosensitivity at high dose exposure.

  4. Assessment of Targeted and Non-Targeted Responses in Cells Deficient in ATM Function following Exposure to Low and High Dose X-Rays

    PubMed Central

    Heinävaara, Sirpa; Pylkäs, Katri; Chapman, Kim; Koivistoinen, Armi; Parviainen, Teuvo; Winqvist, Robert; Kadhim, Munira; Launonen, Virpi; Lindholm, Carita

    2014-01-01

    Radiation sensitivity at low and high dose exposure to X-rays was investigated by means of chromosomal aberration (CA) analysis in heterozygous ATM mutation carrier and A-T patient (biallelic ATM mutation) lymphoblastoid cell lines (LCLs). Targeted and non-targeted responses to acutely delivered irradiation were examined by applying a co-culture system that enables study of both directly irradiated cells and medium-mediated bystander effects in the same experimental setting. No indication of radiation hypersensitivity was observed at doses of 0.01 Gy or 0.1 Gy for the ATM mutation carrier LCL. The A-T patient cells also did not show low-dose response. There was significant increase in unstable CA yields for both ATM mutation carrier and A-T LCLs at 1 and 2 Gy, the A-T cells displaying more distinct dose dependency. Both chromosome and chromatid type aberrations were induced at an increased rate in the irradiated A-T cells, whereas for ATM carrier cells, only unstable chromosomal aberrations were increased above the level observed in the wild type cell line. No bystander effect could be demonstrated in any of the cell lines or doses applied. Characteristics typical for the A-T cell line were detected, i.e., high baseline frequency of CA that increased with dose. In addition, dose-dependent loss of cell viability was observed. In conclusion, CA analysis did not demonstrate low-dose (≤100 mGy) radiosensitivity in ATM mutation carrier cells or A-T patient cells. However, both cell lines showed increased radiosensitivity at high dose exposure. PMID:24681528

  5. [Induction of micronuclei in peripheral blood and bone marrow reticulocytes of male mice after subchronic exposure to x-rays and bisphenol A].

    PubMed

    Radzikowska, Joanna; Gajowik, Aneta; Dobrzyńska, Małgorzata

    2012-01-01

    Ionizing radiation and xenoestrogens are widely present in the human environment. Bisphenol A (BPA) is used to manufacture polycarbonate plastics, epoxy and polyester resins. BPA is present in a great variety of products including: baby bottles, compact disks, thermal paper, safety helmets, bullet resistant laminate, plastic windows, car parts, adhesives, protective coatings, powder paints, polycarbonate bottles and containers, the sheathing of electrical and electronic parts, dental fillings. Food and beverage cans are protected from rusting and corrosion by the application of epoxy resins as inner coatings. Human activities involving the use of radiation and radioactive materials in industry, agriculture and research cause radiation exposure in addition to natural exposure coming from cosmic rays and naturally occurring radioactive substances. The aim of the study was to estimate the effects of bisphenol A, X-rays and combined exposure to X-rays and bisphenol A on the induction of micronuclei in the peripheral blood and in bone marrow reticulocytes of laboratory mice. Pzh-Sfis male mice were exposed for 8 weeks. Animals were treated with bisphenol A diluted in drinking water (5 mg/kg bw, 10 mg/kg bw, 20 mg/kg bw), irradiated 0.05 Gy of X-rays or exposed to a combination of both (0.05 Gy + 5 mg/kg bw BPA). The samples of peripheral blood were taken at 1, 4 and 8 week following the start of exposure, whereas the bone marrow after the end of experiment, only. The induction of micronuclei in reticulocytes were evaluated by using fluorescence microscope. Bisphenol A as well as ionizing radiation stimulated induction of micronuclei in peripheral blood and bone marrow reticulocytes. After the irradiation the level of micronuclei increased, whereas after exposure to BPA decreased related to time expired from beginning of experiment. Combined exposure of ionizing radiation and bisphenol A induced significantly higher frequency of micronuclei compared to the effect

  6. Thoracic spine x-ray

    MedlinePlus

    Vertebral radiography; X-ray - spine; Thoracic x-ray; Spine x-ray; Thoracic spine films; Back films ... care provider's office. You will lie on the x-ray table in different positions. If the x-ray ...

  7. Ikaros is a critical target during simultaneous exposure to X-rays and N-ethyl-N-nitrosourea in mouse T-cell lymphomagenesis.

    PubMed

    Hirano, Shinobu; Kakinuma, Shizuko; Amasaki, Yoshiko; Nishimura, Mayumi; Imaoka, Tatsuhiko; Fujimoto, Shinji; Hino, Okio; Shimada, Yoshiya

    2013-01-15

    Cancer risk associated with radiation exposure is considered the result of concurrent exposure to other natural and manmade carcinogens. Available data on the molecular characteristics of cancer after simultaneous exposure to radiation and chemicals are insufficient. In our study, we used a mouse thymic lymphoma (TL) model that was synergistically induced by simultaneous exposure to X-rays and N-ethyl-N-nitrosourea (ENU) at subcarcinogenic doses and analyzed the mutation frequency and spectrum of the TL-associated genes Ikaros, Notch1, p53 and Kras. We found that the point mutation frequency in Ikaros was significantly increased to 47% for simultaneous exposure compared to 13 and 0% for X-ray and ENU exposure alone, respectively. These mutations were mostly G:C > A:T at non-CpG sites and T:A > C:G, both of which are characteristic of ENU mutagenesis. About half of the point mutations were accompanied by loss of heterozygosity (LOH), typical of X-irradiation. The remaining half did not include LOH, which suggests that they were dominant-negative mutations. In Notch1, the frequency of abnormalities was high (>58%) regardless of the treatment, suggesting that Notch1 aberration may be important for T-cell lymphomagenesis. The p53 and Kras mutation frequencies were low for all treatments (<23%). Importantly, the frequency of TLs containing mutations in multiple genes, especially both Ikaros and Notch1, increased after simultaneous exposure. Thus, after simultaneous exposure, Ikaros is a critical target and is inactivated by ENU-induced point mutations and/or X-ray-induced LOH in T-cell lymphomagenesis. Furthermore, concomitant alterations of multiple tumor-associated genes may contribute to enhanced lymphomagenesis after simultaneous exposure.

  8. Bone x-ray

    MedlinePlus

    ... not being scanned. Alternative Names X-ray - bone Images Skeleton Skeletal spine Osteogenic sarcoma - x-ray References ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...

  9. Dental x-rays

    MedlinePlus

    X-ray - teeth; Radiograph - dental; Bitewings; Periapical film; Panoramic film; Digital image ... dentist's office. There are many types of dental x-rays. Some of them are: Bitewing. Shows the crown ...

  10. X-ray (image)

    MedlinePlus

    X-rays are a form of ionizing radiation that can penetrate the body to form an image on ... will be shades of gray depending on density. X-rays can provide information about obstructions, tumors, and other ...

  11. X-Ray Lasers

    ERIC Educational Resources Information Center

    Chapline, George; Wood, Lowell

    1975-01-01

    Outlines the prospects of generating coherent x rays using high-power lasers and indentifies problem areas in their development. Indicates possible applications for coherent x rays in the fields of chemistry, biology, and crystallography. (GS)

  12. X-ray

    MedlinePlus

    ... image. For most x-rays, the risk of cancer or defects is very low. Most experts feel that the benefits of appropriate x-ray ... Geleijns J, Tack D. Medical physics: radiation risks. In: Adam A, Dixon AK, Gillard ...

  13. X-Ray Toolkit

    SciTech Connect

    2015-10-20

    Radiographic Image Acquisition & Processing Software for Security Markets. Used in operation of commercial x-ray scanners and manipulation of x-ray images for emergency responders including State, Local, Federal, and US Military bomb technicians and analysts.

  14. Assessment of occupational exposure to manganese and other metals in welding fumes by portable X-ray fluorescence spectrometer.

    PubMed

    Laohaudomchok, Wisanti; Cavallari, Jennifer M; Fang, Shona C; Lin, Xihong; Herrick, Robert F; Christiani, David C; Weisskopf, Marc G

    2010-08-01

    Elemental analysis of welding fume samples can be done using several laboratory-based techniques. However, portable measurement techniques could offer several advantages. In this study, we sought to determine whether the portable X-ray fluorescence spectrometer (XRF) is suitable for analysis of five metals (manganese, iron, zinc, copper, and chromium) on 37-mm polytetrafluoroethylene filters. Using this filter fitted on a cyclone in line with a personal pump, gravimetric samples were collected from a group of boilermakers exposed to welding fumes. We assessed the assumption of uniform deposition of these metals on the filters, and the relationships between measurement results of each metal obtained from traditional laboratory-based XRF and the portable XRF. For all five metals of interest, repeated measurements with the portable XRF at the same filter area showed good consistency (reliability ratios are equal or close to 1.0 for almost all metals). The portable XRF readings taken from three different areas of each filter were not significantly different (p-values = 0.77 to 0.98). This suggested that the metal rich PM(2.5) deposits uniformly on the samples collected using this gravimetric method. For comparison of the two XRFs, the results from the portable XRF were well correlated and highly predictive of those from the laboratory XRF. The Spearman correlation coefficients were from 0.325 for chromium, to 0.995 for manganese and 0.998 for iron. The mean differences as a percent of the mean laboratory XRF readings were also small (<5%) for manganese, iron, and copper. The differences were greater for zinc and chromium, which were present at very low amounts in our samples and below the limits of detection of the portable XRF for many of the samples. These five metals were moderately to strongly correlated with the total fine particle fraction on filters (Spearman rho = 0.41 for zinc to 0.97 for iron). Such strong correlations and comparable results suggested that

  15. Assessment of Occupational Exposure to Manganese and Other Metals in Welding Fumes by Portable X-ray Fluorescence Spectrometer

    PubMed Central

    Laohaudomchok, Wisanti; Cavallari, Jennifer M.; Fang, Shona C.; Lin, Xihong; Herrick, Robert F.; Christiani, David C.; Weisskopf, Marc G.

    2011-01-01

    Elemental analysis of welding fume samples can be done using several laboratory-based techniques. However, portable measurement techniques could offer several advantages. In this study, we sought to determine whether the portable X-ray fluorescence spectrometer (XRF) is suitable for analysis of five metals (manganese, iron, zinc, copper, and chromium) on 37-mm polytetrafluoroethylene filters. Using this filter fitted on a cyclone in line with a personal pump, gravimetric samples were collected from a group of boilermakers exposed to welding fumes. We assessed the assumption of uniform deposition of these metals on the filters, and the relationships between measurement results of each metal obtained from traditional laboratory-based XRF and the portable XRF. For all five metals of interest, repeated measurements with the portable XRF at the same filter area showed good consistency (reliability ratios are equal or close to 1.0 for almost all metals). The portable XRF readings taken from three different areas of each filter were not significantly different (p-values = 0.77 to 0.98). This suggested that the metal rich PM2.5 deposits uniformly on the samples collected using this gravimetric method. For comparison of the two XRFs, the results from the portable XRF were well correlated and highly predictive of those from the laboratory XRF. The Spearman correlation coefficients were from 0.325 for chromium, to 0.995 for manganese and 0.998 for iron. The mean differences as a percent of the mean laboratory XRF readings were also small (<5%) for manganese, iron, and copper. The differences were greater for zinc and chromium, which were present at very low amounts in our samples and below the limits of detection of the portable XRF for many of the samples. These five metals were moderately to strongly correlated with the total fine particle fraction on filters (Spearman ρ = 0.41 for zinc to 0.97 for iron). Such strong correlations and comparable results suggested that the

  16. Sinus x-ray

    MedlinePlus

    Paranasal sinus radiography; X-ray - sinuses ... sinus x-ray is taken in a hospital radiology department. Or the x-ray may be taken ... Brown J, Rout J. ENT, neck, and dental radiology. In: Adam A, Dixon AK, Gillard JH Schaefer- ...

  17. Hand x-ray

    MedlinePlus

    X-ray - hand ... A hand x-ray is taken in a hospital radiology department or your health care provider's office by an ... technician. You will be asked to place your hand on the x-ray table, and keep it ...

  18. CONDENSED MATTER: STRUCTURE, MECHANICAL AND THERMAL PROPERTIES: Fabrication of 11-nm-Wide Silica-Like Lines Using X-Ray Diffraction Exposure

    NASA Astrophysics Data System (ADS)

    Zhu, Xiao-Li; Xie, Chang-Qing; Zhang, Man-Hong; Liu, Ming; Chen, Bao-Qin; Pan, Feng

    2009-08-01

    Fine silica-like lines with 11 nm width are successfully fabricated using x-ray Fresnel diffraction exposure. X-rays pass a mask of 175-nm-wide lines and 125-nm-wide spaces and form sharp peaks on a wafer coated with a layer of hydrogen silsesquioxane resist (HSQ). By precisely controlling the mask-wafer gap at 10 μm using the laser interferogram method, the fine structures are defined on HSQ. Experimental images are reproduced by a simulation using the one-dimensional beam propagation method. This lithographic technique presents a novel and convenient way to fabricate fine silica-like structures and devices in nano-optical and nanoelectronic applications.

  19. A study on the dependence of exposure dose reduction and image evaluation on the distance from the dental periapical X-ray machine

    NASA Astrophysics Data System (ADS)

    Joo, Kyu-Ji; Shin, Jae-Woo; Dong, Kyung-Rae; Lim, Chang-Seon; Chung, Woon-Kwan; Kim, Young-Jae

    2013-11-01

    Reducing the exposure dose from a periapical X-ray machine is an important aim in dental radiography. Although the radiation exposure dose is generally low, any radiation exposure is harmful to the human body. Therefore, this study developed a method that reduces the exposure dose significantly compared to that encountered in a normal procedure, but still produces an image with a similar resolution. The correlation between the image resolution and the exposure dose of the proposed method was examined with increasing distance between the dosimeter and the X-ray tube. The results were compared with those obtained from the existing radiography method. When periapical radiography was performed once according to the recommendations of the International Commission on Radiological Protection (ICRP), the measured skin surface dose was low at 7 mGy or below. In contrast, the skin surface dose measured using the proposed method was only 1.57 mGy, showing a five-fold reduction. These results suggest that further decreases in dose might be achieved using the proposed method.

  20. The effect of air exposure on the crystal structure of oligo-thiophene thin films investigated using in situ X-ray diffraction

    NASA Astrophysics Data System (ADS)

    Watanabe, Takeshi; Koganezawa, Tomoyuki; Kikuchi, Mamoru; Videlot-Ackermann, Christine; Ackermann, Jörg; Brisset, Hugues; Yoshimoto, Noriyuki; Hirosawa, Ichiro

    2017-06-01

    The effect of air exposure on the crystal structure of alkyl substituted organic thin film was studied using in situ grazing incidence X-ray diffraction (GIXD) measurements. The GIXD measurements were carried out by scanning the specific qxy region using a two-dimensional area detector and the Soller slit. The a and b axes of the monoclinic unit cell were found to shrink by air exposure. As for the c axis, there was no detectable change caused by air exposure. The shrinking of the a and b axes immediately occurred after exposure to air, and then saturated in six days. The shrinking of the a and b axes by air exposure might affect the transport properties, because shortening between intermolecular distances should promote the hopping of hole carriers.

  1. Formation of secondary electron cascades in single-crystalline plasma-deposited diamond upon exposure to femtosecond x-ray pulses

    SciTech Connect

    Gabrysch, M.; Isberg, J.; Marklund, E.; Caleman, C.; Hajdu, J. |; Twitchen, D. J.; Rudati, J.; Emma, P. J.; Krejcik, P.; Schlarb, H.; Arthur, J.; Brennan, S.; Hastings, J.; Lindenberg, A. M. |; Falcone, R. W.; Tschentscher, T.; Moffat, K.; Bucksbaum, P. H.; Als-Nielsen, J.; Nelson, A. J.

    2008-03-15

    Secondary electron cascades were measured in high purity single-crystalline chemical vapor deposition (CVD) diamond, following exposure to ultrashort hard x-ray pulses (140 fs full width at half maximum, 8.9 keV energy) from the Sub-Picosecond Pulse Source at the Stanford Linear Accelerator Center. We report measurements of the pair creation energy and of drift mobility of carriers in two CVD diamond crystals. This was done for the first time using femtosecond x-ray excitation. Values for the average pair creation energy were found to be 12.17{+-}0.57 and 11.81{+-}0.59 eV for the two crystals, respectively. These values are in good agreement with recent theoretical predictions. The average drift mobility of carriers, obtained by the best fit to device simulations, was {mu}{sub h}=2750 cm{sup 2}/V s for holes and was {mu}{sub e}=2760 cm{sup 2}/V s for electrons. These mobility values represent lower bounds for charge mobilities due to possible polarization of the samples. The results demonstrate outstanding electric properties and the enormous potential of diamond in ultrafast x-ray detectors.

  2. Component analysis of a new Solid State X-ray Image Intensifier (SSXII) using photon transfer and Instrumentation Noise Equivalent Exposure (INEE) measurements.

    PubMed

    Kuhls-Gilcrist, Andrew; Bednarek, Daniel R; Rudin, Stephen

    2009-01-01

    The SSXII is a novel x-ray imager designed to improve upon the performance limitations of conventional dynamic radiographic/fluoroscopic imagers related to resolution, charge-trapping, frame-rate, and instrumentation-noise. The SSXII consists of a CsI:Tl phosphor coupled via a fiber-optic taper (FOT) to an electron-multiplying CCD (EMCCD). To facilitate investigational studies, initial designs enable interchangeability of such imaging components. Measurements of various component and configuration characteristics enable an optimization analysis with respect to overall detector performance. Photon transfer was used to characterize the EMCCD performance including ADC sensitivity, read-noise, full-well capacity and quantum efficiency. X-ray sensitivity was measured using RQA x-ray spectra. Imaging components were analyzed in terms of their MTF and transmission efficiency. The EMCCD was measured to have a very low effective read-noise of less than 1 electron rms at modest EMCCD gains, which is more than two orders-of-magnitude less than flat panel (FPD) and CMOS-based detectors. The variable signal amplification from 1 to 2000 times enables selectable sensitivities ranging from 8.5 (168) to over 15k (300k) electrons per incident x-ray photon with (without) a 4:1 FOT; these sensitivities could be readily increased with further component optimization. MTF and DQE measurements indicate the SSXII performance is comparable to current state-of-the-art detectors at low spatial frequencies and far exceeds them at higher spatial frequencies. The instrumentation noise equivalent exposure (INEE) was measured to be less than 0.3 μR out to 10 cycles/mm, which is substantially better than FPDs. Component analysis suggests that these improvements can be substantially increased with further detector optimization.

  3. Component analysis of a new solid state x-ray image intensifier (SSXII) using photon transfer and instrumentation noise equivalent exposure (INEE) measurements

    NASA Astrophysics Data System (ADS)

    Kuhls-Gilcrist, Andrew; Bednarek, Daniel R.; Rudin, Stephen

    2009-02-01

    The SSXII is a novel x-ray imager designed to improve upon the performance limitations of conventional dynamic radiographic/fluoroscopic imagers related to resolution, charge-trapping, frame-rate, and instrumentation-noise. The SSXII consists of a CsI:Tl phosphor coupled via a fiber-optic taper (FOT) to an electron-multiplying CCD (EMCCD). To facilitate investigational studies, initial designs enable interchangeability of such imaging components. Measurements of various component and configuration characteristics enable an optimization analysis with respect to overall detector performance. Photon transfer was used to characterize the EMCCD performance including ADC sensitivity, read-noise, full-well capacity and quantum efficiency. X-ray sensitivity was measured using RQA x-ray spectra. Imaging components were analyzed in terms of their MTF and transmission efficiency. The EMCCD was measured to have a very low effective read-noise of less than 1 electron rms at modest EMCCD gains, which is more than two orders-ofmagnitude less than flat panel (FPD) and CMOS-based detectors. The variable signal amplification from 1 to 2000 times enables selectable sensitivities ranging from 8.5 (168) to over 15k (300k) electrons per incident x-ray photon with (without) a 4:1 FOT; these sensitivities could be readily increased with further component optimization. MTF and DQE measurements indicate the SSXII performance is comparable to current state-of-the-art detectors at low spatial frequencies and far exceeds them at higher spatial frequencies. The instrumentation noise equivalent exposure (INEE) was measured to be less than 0.3 μR out to 10 cycles/mm, which is substantially better than FPDs. Component analysis suggests that these improvements can be substantially increased with further detector optimization.

  4. Roles of oxidative stress in synchrotron radiation X-ray-induced testicular damage of rodents

    PubMed Central

    Ma, Yingxin; Nie, Hui; Sheng, Caibin; Chen, Heyu; Wang, Ban; Liu, Tengyuan; Shao, Jiaxiang; He, Xin; Zhang, Tingting; Zheng, Chaobo; Xia, Weiliang; Ying, Weihai

    2012-01-01

    Synchrotron radiation (SR) X-ray has characteristic properties such as coherence and high photon flux, which has excellent potential for its applications in medical imaging and cancer treatment. However, there is little information regarding the mechanisms underlying the damaging effects of SR X-ray on biological tissues. Oxidative stress plays an important role in the tissue damage induced by conventional X-ray, while the role of oxidative stress in the tissue injury induced by SR X-ray remains unknown. In this study we used the male gonads of rats as a model to study the roles of oxidative stress in SR X-ray-induced tissue damage. Exposures of the testes to SR X-ray at various radiation doses did not significantly increase the lipid peroxidation of the tissues, assessed at one day after the irradiation. No significant decreases in the levels of GSH or total antioxidation capacity were found in the SR X-ray-irradiated testes. However, the SR X-ray at 40 Gy induced a marked increase in phosphorylated H2AX – a marker of double-strand DNA damage, which was significantly decreased by the antioxidant N-acetyl cysteine (NAC). NAC also attenuated the SR X-ray-induced decreases in the cell layer number of seminiferous tubules. Collectively, our observations have provided the first characterization of SR X-ray-induced oxidative damage of biological tissues: SR X-ray at high doses can induce DNA damage and certain tissue damage during the acute phase of the irradiation, at least partially by generating oxidative stress. However, SR X-ray of various radiation doses did not increase lipid peroxidation. PMID:22837810

  5. Synchrotron microscopic X-ray fluorescence analysis of the effects of chronic arsenic exposure in rat brain

    NASA Astrophysics Data System (ADS)

    Rubio, Marcelo; Perez, Roberto D.; Perez, Carlos A.; Eynard, Aldo H.; Bongiovanni, Guillermina A.

    2008-01-01

    Synchrotron microscopic X-ray fluorescence (μ-SRXRF) scanning and conventional XRF analysis were applied for studying elemental concentrations in lyophilised brain rat slices. The animals received drinking water—100 ppm of sodium arsenite—ad libitum for 30 and 60 days. Accumulation of arsenic was corroborated and its dependence with arsenic dosage suggests the existence of a protection mechanism which limits the transport of inorganic arsenic to the brain. Chlorine, potassium and iron were reduced changing their spatial distributions while copper and zinc were redistributed.

  6. Distinct Sets of lncRNAs are Differentially Modulated after Exposure to High and Low Doses of X Rays.

    PubMed

    Terradas, Mariona; Martín, Marta; Repullès, Joan; Huarte, Maite; Genescà, Anna

    2016-12-01

    High- and low-dose X rays are used in medicine as therapeutic and diagnostic tools, respectively. While the cellular response to high-dose radiation is well known, studies on the effects of low-dose radiation and its ability to trigger a proper DNA damage response have had contradictory results. The functions of many signaling and effector proteins of the DNA damage response (DDR) have been described, and are attributed to well-known DDR pathways. However, there has been little known about the contribution of long noncoding RNAs (lncRNAs) to DDR, although there is recent evidence that lncRNAs may be associated with almost all biological functions, including DDR. In this work, we investigated the participation of lncRNAs in the response to different X-ray doses. By microarray analysis, we observed that in human breast epithelial cells, distinct sets of coding and noncoding transcripts are differentially regulated after moderate- and high-dose irradiation compared to those regulated after low-dose irradiation. While the modulated coding and noncoding genes at low doses relate to cell signaling pathways, those affected by moderate and high doses are mostly enriched for cell cycle regulation and apoptotic pathways. Quantification using qPCR of the lncRNAs identified by microarrays allowed the validation of 75% of those regulated at the higher doses. These results indicate that lncRNA expression is regulated by ionizing radiation and that this expression is dose dependent.

  7. Hard X-ray imaging from Explorer

    NASA Technical Reports Server (NTRS)

    Grindlay, J. E.; Murray, S. S.

    1981-01-01

    Coded aperture X-ray detectors were applied to obtain large increases in sensitivity as well as angular resolution. A hard X-ray coded aperture detector concept is described which enables very high sensitivity studies persistent hard X-ray sources and gamma ray bursts. Coded aperture imaging is employed so that approx. 2 min source locations can be derived within a 3 deg field of view. Gamma bursts were located initially to within approx. 2 deg and X-ray/hard X-ray spectra and timing, as well as precise locations, derived for possible burst afterglow emission. It is suggested that hard X-ray imaging should be conducted from an Explorer mission where long exposure times are possible.

  8. X-ray binaries

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Satellite X-ray experiments and ground-based programs aimed at observation of X-ray binaries are discussed. Experiments aboard OAO-3, OSO-8, Ariel 5, Uhuru, and Skylab are included along with rocket and ground-based observations. Major topics covered are: Her X-1, Cyg X-3, Cen X-3, Cyg X-1, the transient source A0620-00, other possible X-ray binaries, and plans and prospects for future observational programs.

  9. Higher Sensitivity in X-Ray Photography

    NASA Technical Reports Server (NTRS)

    Buggle, R. N.

    1986-01-01

    Hidden defects revealed if X-ray energy decreased as exposure progresses. Declining-potential X-ray photography detects fractures in thin metal sheet covered by unbroken sheet of twice thickness. Originally developed to check solder connections on multilayer circuit boards, technique has potential for other nondestructive testing.

  10. Angular correlation functions of X-ray point-like sources in the full exposure XMM-LSS field

    NASA Astrophysics Data System (ADS)

    Elyiv, A.; Clerc, N.; Plionis, M.; Surdej, J.; Pierre, M.; Basilakos, S.; Chiappetti, L.; Gandhi, P.; Gosset, E.; Melnyk, O.; Pacaud, F.

    2012-01-01

    Aims: Our aim is to study the large-scale structure of different types of AGN using the medium-deep XMM-LSS survey. Methods: We measure the two-point angular correlation function of 5700 and 2500 X-ray point-like sources over the 11 sq. deg. XMM-LSS field in the soft (0.5-2 keV) and hard (2-10 keV) bands. For the conversion from the angular to the spatial correlation function we used the Limber integral equation and the luminosity-dependent density evolution model of the AGN X-ray luminosity function. Results: We have found significant angular correlations with the power-law parameters γ = 1.81 ± 0.02, θ0 = 1.3'' ± 0.2'' for the soft, and γ = 2.00 ± 0.04, θ0 = 7.3'' ± 1.0'' for the hard bands. The amplitude of the correlation function w(θ) is higher in the hard than in the soft band for fx ≲ 10-14 erg s-1 cm-2 and lower above this flux limit. We confirm that the clustering strength θ0 grows with the flux limit of the sample, a trend which is also present in the amplitude of the spatial correlation function, but only for the soft band. In the hard band, it remains almost constant with r0 ≃ 10h-1 Mpc, irrespective of the flux limit. Our analysis of AGN subsamples with different hardness ratios shows that the sources with a hard-spectrum are more clustered than soft-spectrum ones. This result may be a hint that the two main types of AGN populate different environments. Finally, we find that our clustering results correspond to an X-ray selected AGN bias factor of 2.5 for the soft band sources (at a median bar{z} ≃ 1.1) and 3.3 for the hard band sources (at a median bar{z} ≃ 1), which translates into a host dark matter halo mass of 1013h-1M⊙ and 1013.7h-1M⊙ for the soft and hard bands, respectively. This paper is dedicated to the memory of Olivier Garcet who has initiated the present work just before his sudden death.

  11. [Optimization of accounting for radiation exposure of patients as a basis for assessing the risk of stochastic effects due to medical X-ray diagnostic irradiation].

    PubMed

    Kalinina, M V; Zhukova, T V; Kononenko, N A

    2013-01-01

    The work is devoted to optimization of the control and accounting for radiation exposure of patients in the X-ray examinations by means of improving existing forms of state statistical survey (form #3-DOZ.). The analysis of the radiation exposure of patients in medical institutions of the Rostov region for the period of 2005-2011 was carried out. It is proposed to exclude the information about the individual patient doses received by calculation; differentiate a group of "adult patients' on age and gender, selecting the reproductive age, discriminate as a separate category of dose-generating, intervention methods of research that will allow to more accurately calculate the risk of the development of stochastic effects of the medical radiation exposure to population.

  12. Variation in the EPR characteristics of nanosized zirconia particles under exposure to X-ray radiation and annealing in hydrogen

    NASA Astrophysics Data System (ADS)

    Bykov, I. P.; Brik, A. B.; Glinchuk, M. D.; Bevz, V. V.; Kalinichenko, E. A.; Konstantinova, T. E.; Danilenko, I. A.

    2008-12-01

    The effects of various external factors on the properties of nanosized zirconia particles are studied using electron paramagnetic resonance. It is shown that x-rays initiate radiation-stimulated oxidation of chromium impurity ions according to the scheme Cr3+ → Cr5+. Annealing of samples in hydrogen at temperatures in the range 250-650°C brings about a substantial decrease in the fraction of chromium ions in the Cr5+ charge state, but subsequent annealing of these samples in air leads to an increase in the Cr5+ fraction. Samples annealed in hydrogen generate a singlet EPR signal with the g factor of 2.0033 ± 0.0005 originating from electrically conducting regions which are formed on the surface of zirconia nanoparticles during their annealing in hydrogen.

  13. Behavior analysis in consumer affairs: encouraging dental professionals to provide consumers with shielding from unnecessary X-ray exposure.

    PubMed Central

    Greene, B F; Neistat, M D

    1983-01-01

    An unobtrusive observation system was developed to determine the extent to which dental professionals in two communities provided lead shielding to patients during X-ray exams. A lengthy baseline revealed low and irregular provision of shielding among half of these professionals. Subsequently, a program was undertaken by a consumer's group in which these professionals were requested to provide shielding and were given confidential feedback regarding its use during the baseline period. The provision of shielding dramatically increased at all offices and was maintained throughout a follow-up period extending to more than 9 months after the program's implementation. Little or no generalized effect was observed in the occurrence of three collateral behaviors that were also assessed throughout the study. PMID:6833165

  14. Differential Bystander Signaling Between Radioresistant Chondrosarcoma Cells and Fibroblasts After X-Ray, Proton, Iron Ion and Carbon Ion Exposures

    SciTech Connect

    Wakatsuki, Masaru

    2012-09-01

    Purpose: Chondrosarcoma is well known as a radioresistant tumor, but the mechanisms underlying that resistance are still unclear. The bystander effect is well documented in the field of radiation biology. We investigated the bystander response induced by X-rays, protons, carbon ions, and iron ions in chondrosarcoma cells using a transwell insert co-culture system that precludes physical contact between targeted and bystander cells. Methods and Materials: Human chondrosarcoma cells were irradiated with 0.1-, 0.5-, 1-, and 2-Gy X-rays, protons, carbon ions or iron ions using a transwell insert co-culture system. Formation of micronuclei and p53 binding protein 1 staining in bystander and irradiated cells were analyzed and bystander signaling between mixed cultures of chondrosarcoma cells, and normal human skin fibroblasts was investigated. Results: In this study, we show that the fraction of cells with DNA damages in irradiated chondrosarcoma cells showed dose-dependent increases with all beams. However, the fraction of cells with DNA damages in all bystander chondrosarcoma cells did not show any change from the levels in control cells. In the bystander signaling between mixed cultures of chondrosarcoma cells and fibroblasts, the amount of micronucleus formation in all bystander chondrosarcoma cells co-cultured with irradiated fibroblasts were the same as the levels for control cells. However, all bystander fibroblasts co-cultured with irradiated chondrosarcoma cells showed significant increases in the fraction of micronucleated cells compared to the rate of control cells. Conclusions: We conclude that chondrosarcoma cells in the transwell insert co-culture system could release bystander stimulations but could not develop bystander responses.

  15. Dynamically-enhanced retention of gold nanoclusters in HeLa cells following X-rays exposure: A cell cycle phase-dependent targeting approach.

    PubMed

    Liu, Yan; Chen, Weiqiang; Zhang, Pengcheng; Jin, Xiaodong; Liu, Xinguo; Li, Ping; Li, Feifei; Zhang, Hongpeng; Zou, Guozhang; Li, Qiang

    2016-06-01

    Cell cycle phase could affect the cellular uptake of nanoparticles. Based on the fact that ionizing radiation exposure can delay cell cycle progression including inducing G2/M phase arrest, we propose that ionizing radiation exposure is a cell cycle phase-dependent targeting approach for intracellular delivery of nano-agents in tumor cells. We synthesized luminescent gold nanoclusters (AuNCs) using a one-pot green synthetic method. Subsequently, we used the as-prepared AuNCs as both "nano-agents" and fluorescent trafficking probes for our study using human cervical carcinoma HeLa cells. Estimating the cellular uptake of AuNCs and cell cycle analysis were performed following X-rays irradiation and cell synchronization. Our work showed that X-rays irradiation could delay the division of HeLa cells and thereby enhance the retention of AuNCs in HeLa cells, which is a reverse strategy compared with other studies on synergistic nano-radiotherapy. Our results demonstrated that the cell cycle synchronization influenced the cellular uptake processes of AuNCs, suggesting that dynamic cell cycle progression could affect the cellular uptake kinetics of AuNCs. We consider that the radiation-induced cell division delay might provide a possible mechanism underlying the enhanced effect for the cellular uptake of AuNCs in irradiated HeLa cells. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  16. Chest X-Ray

    MedlinePlus Videos and Cool Tools

    ... Site Index A-Z Spotlight Recently posted: Anal Cancer Facet Joint Block Video: Lung Cancer Screening Video: Upper GI Tract X-ray Video: ... of lung conditions such as pneumonia, emphysema and cancer. A chest x-ray requires no special preparation. ...

  17. X-ray Spectrometry.

    ERIC Educational Resources Information Center

    Markowicz, Andrzej A.; Van Grieken, Rene E.

    1984-01-01

    Provided is a selective literature survey of X-ray spectrometry from late 1981 to late 1983. Literature examined focuses on: excitation (photon and electron excitation and particle-induced X-ray emission; detection (wavelength-dispersive and energy-dispersive spectrometry); instrumentation and techniques; and on such quantitative analytical…

  18. X-ray beamsplitter

    DOEpatents

    Ceglio, N.M.; Stearns, D.G.; Hawryluk, A.M.; Barbee, T.W. Jr.

    1987-08-07

    An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5--50 pairs of alternate Mo/Si layers with a period of 20--250 A. The support membrane is 10--200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window. 6 figs.

  19. X-Ray

    MedlinePlus

    ... of gray. For some types of X-ray tests, a contrast medium — such as iodine or barium — is introduced into your body to provide greater detail on the images. X-ray technology is used to examine many parts of the ...

  20. Abdominal x-ray

    MedlinePlus

    An abdominal x-ray is an imaging test to look at organs and structures in the abdomen. Organs include the spleen, stomach, and intestines. When the test is done to look at the bladder and kidney structures, it is called a KUB (kidneys, ureters, bladder) x-ray.

  1. X-ray beamsplitter

    DOEpatents

    Ceglio, Natale M.; Stearns, Daniel S.; Hawryluk, Andrew M.; Barbee, Jr., Troy W.

    1989-01-01

    An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5-50 pairs of alternate Mo/Si layers with a period of 20-250 A. The support membrane is 10-200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window.

  2. X-ray lasers

    SciTech Connect

    Elton, R.C.

    1990-01-01

    This paper provides a source that surveys the fundamentals of x-ray lasers and summarizes recent advances. The author emphasizes x-ray lasers created using high temperature plasmas as the medium. Specific topics discussed included electron-collisional excitation pumping, plasma laser pumping, and gamma-ray lasers. Numerous literature references provided.

  3. X-ray lasers

    SciTech Connect

    Elton, R.C.

    1990-01-01

    This book is both an introduction to x-ray lasers and a how-to-guide for specialists. It provides comprehensive overview and describes useful examples of analysis and experiments as background and guidance for researchers undertaking new laser designs. The book collects the knowledge and experience gained in two decades of x-ray laser development.

  4. X-ray Spectrometry.

    ERIC Educational Resources Information Center

    Markowicz, Andrzej A.; Van Grieken, Rene E.

    1984-01-01

    Provided is a selective literature survey of X-ray spectrometry from late 1981 to late 1983. Literature examined focuses on: excitation (photon and electron excitation and particle-induced X-ray emission; detection (wavelength-dispersive and energy-dispersive spectrometry); instrumentation and techniques; and on such quantitative analytical…

  5. X-ray Polarimetry

    NASA Astrophysics Data System (ADS)

    Kallman, T.

    In spite of the recent advances in X-ray instrumentation, polarimetry remains an area which has been virtually unexplored in the last 20 years. The scientific motivation to study polarization has increased during this time: emission models designed to repro- duce X-ray spectra can be tested using polarization, and polarization detected in other wavelength bands makes clear predictions as to the X-ray polarization. Polarization remains the only way to infer geometrical properties of sources which are too small to be spatially resolved. At the same time, there has been recent progress in instrumen- tation which is likely to allow searches for X-ray polarization at levels significantly below what was possible for early detectors. In this talk I will review the history of X-ray polarimetry, discuss some experimental techniques and the scientific problems which can be addressed by future experiments.

  6. X-ray generator

    DOEpatents

    Dawson, John M.

    1976-01-01

    Apparatus and method for producing coherent secondary x-rays that are controlled as to direction by illuminating a mixture of high z and low z gases with an intense burst of primary x-rays. The primary x-rays are produced with a laser activated plasma, and these x-rays strip off the electrons of the high z atoms in the lasing medium, while the low z atoms retain their electrons. The neutral atoms transfer electrons to highly excited states of the highly striped high z ions giving an inverted population which produces the desired coherent x-rays. In one embodiment, a laser, light beam provides a laser spark that produces the intense burst of coherent x-rays that illuminates the mixture of high z and low z gases, whereby the high z atoms are stripped while the low z ones are not, giving the desired mixture of highly ionized and neutral atoms. To this end, the laser spark is produced by injecting a laser light beam, or a plurality of beams, into a first gas in a cylindrical container having an adjacent second gas layer co-axial therewith, the laser producing a plasma and the intense primary x-rays in the first gas, and the second gas containing the high and low atomic number elements for receiving the primary x-rays, whereupon the secondary x-rays are produced therein by stripping desired ions in a neutral gas and transfer of electrons to highly excited states of the stripped ions from the unionized atoms. Means for magnetically confining and stabilizing the plasma are disclosed for controlling the direction of the x-rays.

  7. Coherent x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Pitney, John Allen

    Conventional x-ray diffraction has historically been done under conditions such that the measured signal consists of an incoherent addition of scattering which is coherent only on a length scale determined by the properties of the beam. The result of the incoherent summation is a statistical averaging over the whole illuminated volume of the sample, which yields certain kinds of information with a high degree of precision and has been key to the success of x-ray diffraction in a variety of applications. Coherent x-ray scattering techniques, such as coherent x-ray diffraction (CXD) and x-ray intensity fluctuation spectroscopy (XIFS), attempt to reduce or eliminate any incoherent averaging so that specific, local structures couple to the measurement without being averaged out. In the case of XIFS, the result is analogous to dynamical light scattering, but with sensitivity to length scales less than 200 nm and time scales from 10-3 s to 103 s. When combined with phase retrieval, CXD represents an imaging technique with the penetration, in situ capabilities, and contrast mechanisms associated with x-rays and with a spatial resolution ultimately limited by the x-ray wavelength. In practice, however, the spatial resolution of CXD imaging is limited by exposure to about 100 A. This thesis describes CXD measurements of the binary alloy Cu3Au and the adaptation of phase retrieval methods for the reconstruction of real-space images of Cu3Au antiphase domains. The theoretical foundations of CXD are described in Chapter 1 as derived from the kinematical formulation for x-ray diffraction and from the temporal and spatial coherence of radiation. The antiphase domain structure of Cu 3Au is described, along with the associated reciprocal-space structure which is measured by CXD. CXD measurements place relatively stringent requirements on the coherence properties of the beam and on the detection mechanism of the experiment; these requirements and the means by which they have been

  8. Instrument and method for X-ray diffraction, fluorescence, and crystal texture analysis without sample preparation

    NASA Technical Reports Server (NTRS)

    Gendreau, Keith (Inventor); Martins, Jose Vanderlei (Inventor); Arzoumanian, Zaven (Inventor)

    2010-01-01

    An X-ray diffraction and X-ray fluorescence instrument for analyzing samples having no sample preparation includes a X-ray source configured to output a collimated X-ray beam comprising a continuum spectrum of X-rays to a predetermined coordinate and a photon-counting X-ray imaging spectrometer disposed to receive X-rays output from an unprepared sample disposed at the predetermined coordinate upon exposure of the unprepared sample to the collimated X-ray beam. The X-ray source and the photon-counting X-ray imaging spectrometer are arranged in a reflection geometry relative to the predetermined coordinate.

  9. Lumbar Spine X-Ray as a Standard Investigation for all Low back Pain in Ghana: Is It Evidence Based?

    PubMed

    Tannor, Abena Y

    2017-03-01

    Low back pain (LBP) has a prevalence of 84% in Africa. The commonest form of imaging is plain lumbar spine x-ray. It gives a radiation dose equivalent to 65 times a chest x-ray dose and sends one of the highest doses to the human reproductive organs. The commonest cause of LBP in Africa is degenerative disease. X-ray findings do not change mode of treatment yet most physicians still routinely request for x-rays. This is a systematic review of databases including The Cochrane, CINAHL plus, AMED, and MEDLINE. Key evidence was clinical guidelines on x-ray use for low back pain. Key search terms included low back pain, x-rays, guidelines, Ghana. Four clinical guidelines on LBP emerged from two Systematic Reviews rated excellent and four good Randomized Controlled Trials: The European guidelines for acute and sub-acute non-specific Low Back Pain, The American College of Physicians and the American Pain Society guideline for diagnostic imaging for Low Back Pain, The NICE guidelines for persistent non-specific Low Back Pain and the Ghana Standard Treatment Guidelines (GSTG). All the guidelines agree that a good history and clinical examination for all LBP patients helps in diagnosing. Only GSTG recommends routine plain spinal x-rays. There is strong evidence indicating very little benefit from routine lumbar spine x-rays for all LBP. The GSTG needs to be revised considering the increased risks of radiation exposure and the x-ray costs. None declared.

  10. Elemental changes in hemolymph and urine of Rhodnius prolixus induced by in-vivo exposure to mercury: A study using synchrotron radiation total reflection X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Mantuano, Andrea; Pickler, Arissa; Barroso, Regina C.; de Almeida, André P.; Braz, Delson; Cardoso, Simone C.; Gonzalez, Marcelo S.; Figueiredo, Marcela B.; Garcia, Eloi S.; Azambuja, Patricia

    2012-05-01

    In recent years, the effects of pollution on the health of humans and other vertebrates were extensively studied. However, the effects on some invertebrates are comparatively unknown. Recent studies have demonstrated that toxic metals interfere with the reproduction, development and immune defenses of some terrestrial and marine invertebrates. Some environmental conditions including pollution produce chronic and acute effects on different animal's organs and systems. In this work, we investigated changes in the concentrations of Cl, K, Ca, Fe and Zn in Rhodnius prolixus as insect model. The elements were quantified using urine and hemolymph samples collected on different days after feeding the insects with blood containing HgCl2. The synchrotron radiation total reflection X-ray fluorescence measurements were carried at the X-ray fluorescence beamline facility in Brazilian Synchrotron Light Laboratory. The observation reveals that the calcium level was higher in the hemolymph than in urine. On the other hand, the urine collected from insects treated with HgCl2 showed higher level of Cl than hemolymph samples. Ca, Fe and Zn concentrations decrease drastically in urine samples collected after 2 days of HgCl2 treatment. The regulation of triatomines excretion was discussed pointing out the importance of trace elements.

  11. Indus-2 X-ray lithography beamline for X-ray optics and material science applications

    SciTech Connect

    Dhamgaye, V. P. Lodha, G. S.

    2014-04-24

    X-ray lithography is an ideal technique by which high aspect ratio and high spatial resolution micro/nano structures are fabricated using X-rays from synchrotron radiation source. The technique has been used for fabricating optics (X-ray, visible and infrared), sensors and actuators, fluidics and photonics. A beamline for X-ray lithography is operational on Indus-2. The beamline offers wide lithographic window from 1-40keV photon energy and wide beam for producing microstructures in polymers upto size ∼100mm × 100mm. X-ray exposures are possible in air, vacuum and He gas environment. The air based exposures enables the X-ray irradiation of resist for lithography and also irradiation of biological and liquid samples.

  12. Evaluation of detector dynamic range in the x-ray exposure domain in mammography: a comparison between film-screen and flat panel detector systems.

    PubMed

    Cooper, Virgil N; Oshiro, Thomas; Cagnon, Christopher H; Bassett, Lawrence W; McLeod-Stockmann, Tyler M; Bezrukiy, Nikita V

    2003-10-01

    Digital detectors in mammography have wide dynamic range in addition to the benefit of decoupled acquisition and display. How wide the dynamic range is and how it compares to film-screen systems in the clinical x-ray exposure domain are unclear. In this work, we compare the effective dynamic ranges of film-screen and flat panel mammography systems, along with the dynamic ranges of their component image receptors in the clinical x-ray exposure domain. An ACR mammography phantom was imaged using variable mAs (exposure) values for both systems. The dynamic range of the contrast-limited film-screen system was defined as that ratio of mAs (exposure) values for a 26 kVp Mo/Mo (HVL=0.34 mm Al) beam that yielded passing phantom scores. The same approach was done for the noise-limited digital system. Data from three independent observers delineated a useful phantom background optical density range of 1.27 to 2.63, which corresponded to a dynamic range of 2.3 +/- 0.53. The digital system had a dynamic range of 9.9 +/- 1.8, which was wider than the film-screen system (p<0.02). The dynamic range of the film-screen system was limited by the dynamic range of the film. The digital detector, on the other hand, had an estimated dynamic range of 42, which was wider than the dynamic range of the digital system in its entirety by a factor of 4. The generator/tube combination was the limiting factor in determining the digital system's dynamic range.

  13. Stellar x-ray flares

    NASA Astrophysics Data System (ADS)

    Haisch, B.; Uchida, Y.; Kosugi, T.; Hudson, H. S.

    1995-01-01

    What is the importance of stellar X-ray flares to astrophysics, or even more, to the world at large? In the case of the Sun, changes in solar activity at the two temporal extremes can have quite significant consequences. Longterm changes in solar activity, such as the Maunder Minimum, can apparently lead to non-negligible alterations of the earth's climate. The extreme short term changes are solar flares, the most energetic of which can cause communications disruptions, power outages and ionizing radiation levels amounting to medical X-ray dosages on long commercial flights and even potentially lethal exposures for unshielded astronauts. Why does the Sun exhibit such behaviour? Even if we had a detailed knowledge of the relevant physical processes on the Sun - which we may be on the way to having in hand as evidenced by these Proceedings- our understanding would remain incomplete in regard to fundamental causation so long as we could not say whether the Sun is, in this respect, unique among the stars. This current paper discusses the stellar x-ray flare detections and astronomical models (quasi-static cooling model and two-ribbon model) that are used to observe the x-ray emission.

  14. X-ray crystallography

    NASA Technical Reports Server (NTRS)

    2001-01-01

    X-rays diffracted from a well-ordered protein crystal create sharp patterns of scattered light on film. A computer can use these patterns to generate a model of a protein molecule. To analyze the selected crystal, an X-ray crystallographer shines X-rays through the crystal. Unlike a single dental X-ray, which produces a shadow image of a tooth, these X-rays have to be taken many times from different angles to produce a pattern from the scattered light, a map of the intensity of the X-rays after they diffract through the crystal. The X-rays bounce off the electron clouds that form the outer structure of each atom. A flawed crystal will yield a blurry pattern; a well-ordered protein crystal yields a series of sharp diffraction patterns. From these patterns, researchers build an electron density map. With powerful computers and a lot of calculations, scientists can use the electron density patterns to determine the structure of the protein and make a computer-generated model of the structure. The models let researchers improve their understanding of how the protein functions. They also allow scientists to look for receptor sites and active areas that control a protein's function and role in the progress of diseases. From there, pharmaceutical researchers can design molecules that fit the active site, much like a key and lock, so that the protein is locked without affecting the rest of the body. This is called structure-based drug design.

  15. X-ray crystallography

    NASA Technical Reports Server (NTRS)

    2001-01-01

    X-rays diffracted from a well-ordered protein crystal create sharp patterns of scattered light on film. A computer can use these patterns to generate a model of a protein molecule. To analyze the selected crystal, an X-ray crystallographer shines X-rays through the crystal. Unlike a single dental X-ray, which produces a shadow image of a tooth, these X-rays have to be taken many times from different angles to produce a pattern from the scattered light, a map of the intensity of the X-rays after they diffract through the crystal. The X-rays bounce off the electron clouds that form the outer structure of each atom. A flawed crystal will yield a blurry pattern; a well-ordered protein crystal yields a series of sharp diffraction patterns. From these patterns, researchers build an electron density map. With powerful computers and a lot of calculations, scientists can use the electron density patterns to determine the structure of the protein and make a computer-generated model of the structure. The models let researchers improve their understanding of how the protein functions. They also allow scientists to look for receptor sites and active areas that control a protein's function and role in the progress of diseases. From there, pharmaceutical researchers can design molecules that fit the active site, much like a key and lock, so that the protein is locked without affecting the rest of the body. This is called structure-based drug design.

  16. Evaluation of the radiation dose to a phantom for various X-ray exposure factors performed using the dose area product in digital radiography

    NASA Astrophysics Data System (ADS)

    Kweon, D. C.; Chung, W. K.; Dong, K. R.; Lee, J. W.; Choi, J. W.; Goo, E. H.; Lee, J. S.; Kim, S. G.; Cho, J. H.; Chung, J. E.

    2012-12-01

    The aim of this study is to measure the dose area product (DAP) in digital radiography by using a DAP meter to determine the X-ray exposure. Pediatric X-ray examinations can be obtained for any radiographic examinations using the selected radiographic examination parameters (kVp and mAs), the DAP information recorded. The best peak signal-to-noise ratio (PSNR) at a fixed tube voltage of 70 kVp was obtained at tube currents of 20 and 32 mA, whereas the best PSNR at a fixed tube current of 25 mA was obtained at a tube voltage of 73 kVp. The fixed tube voltage of 70 kVp and the fixed tube current of 25 mA could help to obtain the best image quality and depict the spatial resolution of an anthropomorphic torso phantom radiographic examination. The normalized data over the DAP were provided to determine the patient dose from radiography.

  17. Radiation exposure due to cosmic rays and solar X-ray photons at various atmospheric heights in aviation range over India

    NASA Astrophysics Data System (ADS)

    Palit, Sourav; Chakrabarti, Sandip Kumar; Bhattacharya, Arnab

    2016-07-01

    In this presentation we present our work on the continuous monitoring of radiation exposure in terms of effective dose rates, due to galactic cosmic rays (GCR) and solar X-rays at various altitudes within aviation range over India. As India belongs to equatorial region, there is negligible contribution from solar energetic particles (SEP). The calculation of cosmic ray counts as well as the solar X-ray photons are performed on the basis of the observation of various Dignity series balloon experiments on cosmic ray and solar high energy radiation studies, conducted by ICSP and Monte Carlo simulations performed with GEANT4 detector simulation software. The information on solar activity level from Geostationary Operational Environmental Satellite system (GOES) are employed in the calculations. A program, which is done entirely in MATLAB is employed to update regularly in a website, where we show images of dose rate (μSv) distribution over India at four different heights within the aviation range (updating at an interval of 30 minutes) and the approximate dose rates thats should be experienced by a pilot in an entire flight time between pairs of stations distributed all over India.

  18. X-ray laser

    DOEpatents

    Nilsen, Joseph

    1991-01-01

    An X-ray laser (10) that lases between the K edges of carbon and oxygen, i.e. between 44 and 23 Angstroms, is provided. The laser comprises a silicon (12) and dysprosium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state nickel-like dysprosium ions (34) are resonantly photo-pumped to their upper X-ray laser state by line emission from hydrogen-like silicon ions (32). The novel X-ray laser should prove especially useful for the microscopy of biological specimens.

  19. X-ray superbubbles

    NASA Technical Reports Server (NTRS)

    Cash, W.

    1983-01-01

    Four regions of the galaxy, the Cygnus Superbubble, the Eta Carina complex, the Orion/Eridanus complex, and the Gum Nebula, are discussed as examples of collective effects in the interstellar medium. All four regions share certain features, indicating a common structure. The selection effects which determine the observable X-ray properties of the superbubbles are discussed, and it is demonstrated that only a very few more in our Galaxy can be detected in X rays. X-ray observation of extragalactic superbubbles is shown to be possible but requires the capabilities of a large, high quality, AXAF class observatory.

  20. Chest X-Ray (Chest Radiography)

    MedlinePlus

    ... have very controlled x-ray beams and dose control methods to minimize stray (scatter) radiation. This ensures that those parts of a patient's body not being imaged receive minimal radiation exposure. top ...

  1. Abdomen X-Ray (Radiography)

    MedlinePlus

    ... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Abdomen Abdominal x-ray uses a very ... of an abdominal x-ray? What is abdominal x-ray? An x-ray (radiograph) is a noninvasive medical ...

  2. Analysis of flow cytometry DNA damage response protein activation kinetics after exposure to x rays and high-energy iron nuclei.

    PubMed

    Chappell, Lori J; Whalen, Mary K; Gurai, Sheena; Ponomarev, Artem; Cucinotta, Francis A; Pluth, Janice M

    2010-12-01

    We developed a mathematical method to analyze flow cytometry data to describe the kinetics of γ-H2AX and pATF2 phosphorylation in normal human fibroblast cells after exposure to various qualities of low-dose radiation. Previously reported flow cytometry kinetics for these DSB repair phospho-proteins revealed that distributions of intensity were highly skewed, severely limiting the detection of differences in the very low-dose range. Distributional analysis revealed significant differences between control and low-dose samples when distributions were compared using the Kolmogorov-Smirnov test. Differences in radiation quality were found in the distribution shapes and when a nonlinear model was used to relate dose and time to the decay of the mean ratio of phospho-protein intensities of irradiated samples to controls. We analyzed cell cycle phase- and radiation quality-dependent characteristic repair times and residual phospho-protein levels with these methods. Characteristic repair times for γ-H2AX were higher after exposure to iron nuclei compared to X rays in G(1) cells and in S/G(2) cells. The RBE in G(1) cells for iron nuclei relative to X rays for γ-H2AX was 2.1 ± 0.6 and 5.0 ± 3.5 at 2 and 24 h after irradiation, respectively. For pATF2, a saturation effect was observed with reduced expression at high doses, especially for iron nuclei, with much slower characteristic repair times (>7 h) compared to X rays. RBEs for pATF2 were 0.7 ± 0.1 and 1.7 ± 0.5 at 2 and 24 h, respectively. Significant differences in γ-H2AX and pATF2 levels when irradiated samples were compared to controls were noted even at the lowest dose analyzed (0.05 Gy). These results show that mathematical models can be applied to flow cytometry data to identify important and subtle differences after exposure to various qualities of low-dose radiation.

  3. X-ray calorimeters

    NASA Astrophysics Data System (ADS)

    Porter, F. Scott

    X-ray calorimeter instruments for astrophysics have seen rapid development since they were invented in 1984. The prime instrument on all currently planned X-ray spectroscopic observatories is based on calorimeter technology. This relatively simple detection concept that senses the energy of an incident photon by measuring the temperature rise of an absorber material at very low temperatures can form the basis of a very high-performance, non-dispersive spectrometer. State-of-theart calorimeter instruments have resolving powers of over 3000, large simultaneous bandpasses, and near unit efficiency. This coupled with the intrinsic imaging capability of a pixilated X-ray calorimeter array, allows true spectral-spatial instruments to be constructed. This chapter briefly reviews the detection scheme, the state of the art in X-ray calorimeter instruments and the future outlook for this technology.

  4. X-ray - skeleton

    MedlinePlus

    ... medlineplus.gov/ency/article/003381.htm X-ray - skeleton To use the sharing features on this page, ... ray views may be uncomfortable. If the whole skeleton is being imaged, the test usually takes 1 ...

  5. X-Ray Diffraction.

    ERIC Educational Resources Information Center

    Smith, D. K.; Smith, K. L.

    1980-01-01

    Reviews applications in research and analytical characterization of compounds and materials in the field of X-ray diffraction, emphasizing new developments in applications and instrumentation in both single crystal and powder diffraction. Cites 414 references. (CS)

  6. Solar x ray astronomy rocket program

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The dynamics were studied of the solar corona through the imaging of large scale coronal structures with AS&E High Resolution Soft X ray Imaging Solar Sounding Rocket Payload. The proposal for this program outlined a plan of research based on the construction of a high sensitivity X ray telescope from the optical and electronic components of the previous flight of this payload (36.038CS). Specifically, the X ray sensitive CCD camera was to be placed in the prime focus of the grazing incidence X ray mirror. The improved quantum efficiency of the CCD detector (over the film which had previously been used) allows quantitative measurements of temperature and emission measure in regions of low x ray emission such as helmet streamers beyond 1.2 solar radii or coronal holes. Furthermore, the improved sensitivity of the CCD allows short exposures of bright objects to study unexplored temporal regimes of active region loop evolution.

  7. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1992-01-01

    This final report covers the period 1 January 1985 - 31 March 1992. It is divided into the following sections: the soft x-ray background; proportional counter and filter calibrations; sounding rocket flight preparations; new sounding rocket payload: x-ray calorimeter; and theoretical studies. Staff, publications, conference proceedings, invited talks, contributed talks, colloquia and seminars, public service lectures, and Ph. D. theses are listed.

  8. X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Lewin, Walter H. G.; van Paradijs, Jan; van den Heuvel, Edward Peter Jacobus

    1997-01-01

    Preface; 1. The properties of X-ray binaries, N. E. White, F. Nagase and A. N. Parmar; 2. Optical and ultraviolet observations of X-ray binaries J. van Paradijs and J. E. McClintock; 3. Black-hole binaries Y. Tanaka and W. H. G. Lewin; 4. X-ray bursts Walter H. G. Lewin, Jan Van Paradijs and Ronald E. Taam; 5. Millisecond pulsars D. Bhattacharya; 6. Rapid aperiodic variability in binaries M. van der Klis; 7. Radio properties of X-ray binaries R. M. Hjellming and X. Han; 8. Cataclysmic variable stars France Anne-Dominic Córdova; 9. Normal galaxies and their X-ray binary populations G. Fabbiano; 10. Accretion in close binaries Andrew King; 11. Formation and evolution of neutron stars and black holes in binaries F. Verbunt and E. P. J. van den Heuvel; 12. The magnetic fields of neutron stars and their evolution D. Bhattacharya and G. Srinivasan; 13. Cosmic gamma-ray bursts K. Hurley; 14. A catalogue of X-ray binaries Jan van Paradijs; 15. A compilation of cataclysmic binaries with known or suspected orbital periods Hans Ritter and Ulrich Kolb; References; Index.

  9. Detection of x ray sources in PROS

    NASA Technical Reports Server (NTRS)

    Deponte, J.; Primini, F. A.

    1992-01-01

    The problem of detecting discrete sources in x-ray images has much in common with the problem of automatic source detection at other wavelengths. In all cases, one searches for positive brightness enhancements exceeding a certain threshold, which appear consistent with what one expects for a point source, in the presence of a (possibly) spatially variable background. Multidimensional point spread functions (e.g., dependent on detector position and photon energy) are also common. At the same time, the problem in x-ray astronomy has some unique aspects. For example, for typical x-ray exposures in current or recent observatories, the number of available pixels far exceeds the number of actual x-ray events, so Poisson, rather than Gaussian statistics apply. Further, extended cosmic x-ray sources are common, and one often desires to detect point sources in the vicinity or even within bright, diffuse x-ray emission. Finally, support structures in x-ray detectors often cast sharp shadows in x-ray images making it necessary to detect sources in a region of rapidly varying exposure. We have developed a source detection package within the IRAF/PROS environment which attempts to deal with some of the problems of x-ray source detection. We have patterned our package after the successful Einstein Observatory x-ray source detection programs. However, we have attempted to improve the flexibility and accessibility of the functions and to provide a graphical front-end for the user. Our philosophy has been to use standard IRAF tasks whenever possible for image manipulation and to separate general functions from mission-specific ones. We will report on the current status of the package and discuss future developments, including simulation tasks, to allow the user to assess detection efficiency and source significance, tasks to determine source intensity, and alternative detection algorithms.

  10. 21 CFR 1020.40 - Cabinet x-ray systems.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... electron microscope equipment or to systems for intentional exposure of humans to x-rays. (b) Definitions... electrons (negatrons and positrons) liberated by photons in a volume element of air having mass dm are... assemblage of components for the controlled generation of x-rays. (13) X-ray tube means any electron...

  11. 21 CFR 1020.40 - Cabinet x-ray systems.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... electron microscope equipment or to systems for intentional exposure of humans to x-rays. (b) Definitions... electrons (negatrons and positrons) liberated by photons in a volume element of air having mass dm are... assemblage of components for the controlled generation of x-rays. (13) X-ray tube means any electron...

  12. 21 CFR 1020.40 - Cabinet x-ray systems.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... electron microscope equipment or to systems for intentional exposure of humans to x-rays. (b) Definitions... electrons (negatrons and positrons) liberated by photons in a volume element of air having mass dm are... assemblage of components for the controlled generation of x-rays. (13) X-ray tube means any electron...

  13. Postsplinting x-rays of nondisplaced hand, wrist, ankle, and foot fractures are unnecessary.

    PubMed

    Schuld, Jill C; Volker, Mark L; Anderson, Sarah A; Zwank, Michael D

    2016-08-01

    Acute nondisplaced fractures (NDFs) are common in the emergency department (ED), and providers often obtain postsplinting x-rays to identify displacement that potentially occurs during the splinting process. Our objectives are to (1) determine how often x-rays are obtained after splinting of NDFs, (2) identify if postsplinting x-rays change treatment management in the ED, and (3) identify if there are medical complications at follow-up. A retrospective chart review of ED patients who were discharged with hand, wrist, ankle, or foot fractures was conducted to determine patients with definite NDFs that were verified by a radiologist, underwent splinting, and either had postsplint x-rays or not. Bone displacement during the splinting procedure was determined by the postsplint x-rays in the ED. Internal movement of bones or management change was also determined for patients who did not undergo postsplint x-rays in the ED but had obtained an x-ray at their follow-up visit (in-network providers only). Our results demonstrate that no patients required further manipulation or operative management due to the splinting that occurred in the ED. These results take into account both patients who had postsplint x-rays conducted in the ED (27 patients) and those who received x-rays in follow-up consults (179 patients). There was minimal incidence of interval movement in the latter group (14 patients), none of which resulted in management change. These data conclude that postsplinting x-rays of NDFs are unnecessary. Removal of this procedure from routine practice will help decrease patient and hospital cost, time, and radiation exposure. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Does the application of X-ray contrast agents impair the clinical effect of intravenous recombinant tissue-type plasminogen activator in acute ischemic stroke patients?

    PubMed

    Dzialowski, Imanuel; Puetz, Volker; Buchan, Alastair M; Demchuk, Andrew M; Hill, Michael D

    2012-06-01

    Experimental data suggest a negative interaction between x-ray contrast agents and fibrinolytic efficacy of recombinant tissue-type plasminogen activator (rtPA). We hypothesized that the application of a contrast agent before intravenous thrombolysis with rtPA reduces its clinical efficacy in acute ischemic stroke. We retrospectively studied consecutive ischemic stroke patients receiving contrast agents for computed tomography angiography before intravenous treatment with rtPA. We compared functional outcomes with an historical control group from the Canadian Alteplase for Stroke Effectiveness Study who did not receive contrast agents before thrombolysis with rtPA. Primary end point was favorable functional outcome at 90 days defined as modified Rankin Scale scores 0 to 2. We performed logistic regression analysis and a propensity score matching analysis to estimate the effect size of contrast agent use as a negative predictor of outcome. We identified 111 patients for the computed tomography angiography and 1119 patients for the control group. Proportions of favorable functional outcome were 47.7% (53/111 patients) for the computed tomography angiography group and 49.5% (542/1094 patients) for the control group (P=0.77). Adjusted probabilities for favorable outcome were 0.48 (95% CI, 0.37-0.58) and 0.51 (95% CI, 0.47-0.54), respectively. Contrast use was associated with reduced odds of favorable outcome (OR, 0.62(;) 95% CI, 0.38-0.99). Propensity score matching suggested a larger effect size (OR, 10.0%; 95% CI, 0.5%-19.3%). Our study did not show a significant negative clinical effect of x-ray contrast agents applied before intravenous thrombolysis with rtPA. However, to confirm a possible small negative interaction between contrast agents and rtPA, additional experimental and prospective clinical studies are needed.

  15. Dental x-ray diagnostic installation

    SciTech Connect

    Grassme, U.

    1985-02-19

    An exemplary embodiment comprises an exposure unit including an X-ray tube and a cassette holder rotatable about vertical axes and between which the head of the patient is disposed. A radiation detector is disposed at the cassette holder for supplying an electrical signal corresponding to the dose rate when it is struck by X-rays and being interconnected with an X-ray tube voltage controller and a dose rate regulator in such manner that the X-ray tube voltage is influenced by the output of the radiation detector to control the dose rate to a value producing an optimum film blackening. A function generator determining the speed of the exposure unit is provided in which a speed curve is stored given which the radiation dose influencing the film is approximately constant.

  16. Photon-exposure-dependent photon-stimulated desorption for obtaining photolysis cross section of molecules adsorbed on surface by monochromatic soft x-ray photons.

    PubMed

    Chou, L-C; Jang, C-Y; Wu, Y-H; Tsai, W-C; Wang, S-K; Chen, J; Chang, S-C; Liu, C-C; Shai, Y; Wen, C-R

    2008-12-07

    Photon-exposure-dependent positive- and negative-ion photon-stimulated desorption (PSD) was proposed to study the photoreactions and obtain the photolysis cross sections of molecules adsorbed on a single-crystal surface by monochromatic soft x-ray photons with energy near the core level of adsorbate. The changes in the F(+) and F(-) PSD ion yields were measured from CF(3)Cl molecules adsorbed on Si(111)-7x7 at 30 K (CF(3)Cl dose=0.3x10(15) molecules/cm(2), approximately 0.75 monolayer) during irradiation of monochromatic soft x-ray photons near the F(1s) edge. The PSD ion yield data show the following characteristics: (a) The dissociation of adsorbed CF(3)Cl molecules is due to a combination of direct photodissociation via excitation of F(1s) core level and substrate-mediated dissociation [dissociative attachment and dipolar dissociation induced by the photoelectrons emitting from the silicon substrate]. (b) the F(+) ion desorption is associated with the bond breaking of the surface CF(3)Cl, CF(2)Cl, CFCl, and SiF species. (c) the F(-) yield is mainly due to DA and DD of the adsorbed CF(3)Cl molecules. (d) The surface SiF is formed by reaction of the surface Si atom with the neutral fluorine atom, F(+), or F(-) ion produced by scission of C-F bond of CF(3)Cl, CF(2)Cl, or CFCl species. A kinetic model was proposed for the explanation of the photolysis of this submonolayer CF(3)Cl-covered surface. Based on this model and the variation rates of the F(+)F(-) signals during fixed-energy monochromatic photon bombardment at 690.2 and 692.6 eV [near the F(1s) edge], the photolysis cross section was deduced as a function of energy.

  17. Photon-exposure-dependent photon-stimulated desorption for obtaining photolysis cross section of molecules adsorbed on surface by monochromatic soft x-ray photons

    NASA Astrophysics Data System (ADS)

    Chou, L.-C.; Jang, C.-Y.; Wu, Y.-H.; Tsai, W.-C.; Wang, S.-K.; Chen, J.; Chang, S.-C.; Liu, C.-C.; Shai, Y.; Wen, C.-R.

    2008-12-01

    Photon-exposure-dependent positive- and negative-ion photon-stimulated desorption (PSD) was proposed to study the photoreactions and obtain the photolysis cross sections of molecules adsorbed on a single-crystal surface by monochromatic soft x-ray photons with energy near the core level of adsorbate. The changes in the F+ and F- PSD ion yields were measured from CF3Cl molecules adsorbed on Si(111)-7×7 at 30K (CF3Cl dose=0.3×1015molecules/cm2, ˜0.75 monolayer) during irradiation of monochromatic soft x-ray photons near the F(1s ) edge. The PSD ion yield data show the following characteristics: (a) The dissociation of adsorbed CF3Cl molecules is due to a combination of direct photodissociation via excitation of F(1s ) core level and substrate-mediated dissociation [dissociative attachment and dipolar dissociation induced by the photoelectrons emitting from the silicon substrate]. (b) the F+ ion desorption is associated with the bond breaking of the surface CF3Cl, CF2Cl, CFCl, and SiF species. (c) the F - yield is mainly due to DA and DD of the adsorbed CF3Cl molecules. (d) The surface SiF is formed by reaction of the surface Si atom with the neutral fluorine atom, F +, or F- ion produced by scission of C-F bond of CF3Cl, CF2Cl, or CFCl species. A kinetic model was proposed for the explanation of the photolysis of this submonolayer CF3Cl-covered surface. Based on this model and the variation rates of the F +/F- signals during fixed-energy monochromatic photon bombardment at 690.2 and 692.6eV [near the F(1s ) edge], the photolysis cross section was deduced as a function of energy.

  18. Comparison between two FISH techniques in the in vitro study of cytogenetic markers for low-dose X-ray exposure in human primary fibroblasts

    PubMed Central

    Nieri, D.; Berardinelli, F.; Antoccia, A.; Tanzarella, C.; Sgura, Antonella

    2013-01-01

    This work is about the setup of an in vitro system to report low-dose of X-rays as measured as cytogenetic damage. Q- and multicolor FISH (m-FISH), for telomere length and chromosome instability analysis, respectively, were compared to evaluate their sensitivity in the low-dose range in human primary fibroblasts. No telomere length modulation was observed up to 1 Gy in cycling fibroblasts, though reported for high doses, by that frustrating the purpose of using it as a low-exposure marker. To date the m-FISH is the best setup for the assessment of the chromosome structural damage: it allows stable and instable aberrations to be detected all over the karyotype. Stable ones such as balanced translocations, are not eliminated due to cell-cycle as unstable ones, so they are considered transmissible markers for retrospective dosimetry. The induction of chromosome damage showed a clear dependence on dose delivered; unstable aberrations were demonstrated after doses of 0.1 Gy, and stable aberrations after doses higher than 0.5 Gy. Summarizing, q-FISH is unfit to report low exposures while m-FISH provides better results: unstable aberrations are sensible short-term reporters, while stable ones long report exposures but with a higher induction threshold. PMID:23908663

  19. Exposure and analysis of microparticles embedded in silica aerogel keystones using NF3-mediated electron beam-induced etching and energy-dispersive X-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Martin, Aiden A.; Lin, Ting; Toth, Milos; Westphal, Andrew J.; Vicenzi, Edward P.; Beeman, Jeffrey; Silver, Eric H.

    2016-07-01

    In 2006, NASA's Stardust spacecraft delivered to Earth dust particles collected from the coma of comet 81P/Wild 2, with the goal of furthering the understanding of solar system formation. Stardust cometary samples were collected in a low-density, nanoporous silica aerogel making their study technically challenging. This article demonstrates the identification, exposure, and elemental composition analysis of particles analogous to those collected by NASA's Stardust mission using in-situ SEM techniques. Backscattered electron imaging is shown by experimental observation and Monte Carlo simulation to be suitable for locating particles of a range of sizes relevant to Stardust (down to submicron diameters) embedded within silica aerogel. Selective removal of the silica aerogel encapsulating an embedded particle is performed by cryogenic NF3-mediated electron beam-induced etching. The porous, low-density nature of the aerogel results in an enhanced etch rate compared with solid material, making it an effective, nonmechanical method for the exposure of particles. After exposure, elemental composition of the particle was analyzed by energy-dispersive X-ray spectroscopy using a high spectral resolution microcalorimeter. Signals from fluorine contamination are shown to correspond to nonremoved silica aerogel and only in residual concentrations.

  20. Clocking femtosecond X rays.

    PubMed

    Cavalieri, A L; Fritz, D M; Lee, S H; Bucksbaum, P H; Reis, D A; Rudati, J; Mills, D M; Fuoss, P H; Stephenson, G B; Kao, C C; Siddons, D P; Lowney, D P; Macphee, A G; Weinstein, D; Falcone, R W; Pahl, R; Als-Nielsen, J; Blome, C; Düsterer, S; Ischebeck, R; Schlarb, H; Schulte-Schrepping, H; Tschentscher, Th; Schneider, J; Hignette, O; Sette, F; Sokolowski-Tinten, K; Chapman, H N; Lee, R W; Hansen, T N; Synnergren, O; Larsson, J; Techert, S; Sheppard, J; Wark, J S; Bergh, M; Caleman, C; Huldt, G; van der Spoel, D; Timneanu, N; Hajdu, J; Akre, R A; Bong, E; Emma, P; Krejcik, P; Arthur, J; Brennan, S; Gaffney, K J; Lindenberg, A M; Luening, K; Hastings, J B

    2005-03-25

    Linear-accelerator-based sources will revolutionize ultrafast x-ray science due to their unprecedented brightness and short pulse duration. However, time-resolved studies at the resolution of the x-ray pulse duration are hampered by the inability to precisely synchronize an external laser to the accelerator. At the Sub-Picosecond Pulse Source at the Stanford Linear-Accelerator Center we solved this problem by measuring the arrival time of each high energy electron bunch with electro-optic sampling. This measurement indirectly determined the arrival time of each x-ray pulse relative to an external pump laser pulse with a time resolution of better than 60 fs rms.

  1. Fabrication of large area X-ray diffraction grating for X-ray phase imaging

    SciTech Connect

    Noda, Daiji; Tokuoka, Atsushi; Katori, Megumi; Minamiyama, Yasuto; Yamashita, Kenji; Nishida, Satoshi; Hattori, Tadashi

    2012-07-31

    X-ray lithography, which uses highly directional synchrotron radiation, is one of the technologies that can be used for fabricating micrometer-sized structures. In X-ray lithography, the accuracy of the fabricated structure depends largely on the accuracy of the X-ray mask. Since X-ray radiation is highly directional, a micro-fabrication technology that produces un-tapered and high aspect ratio highly absorbent structures on a low absorbent membrane is required. Conventionally, a resin material is used as the support membrane for large area X-ray masks. However, resin membranes have the disadvantage that they can sag after several cycles of X-ray exposure due to the heat generated by the X-rays. Therefore, we proposed and used thin carbon wafers for the membrane material because carbon has an extremely small thermal expansion coefficient. We fabricated new carbon membrane X-ray masks, and these results of X-ray lithography demonstrate the superior performance.

  2. X-ray Reflection

    NASA Astrophysics Data System (ADS)

    Fabian, A. C.; Ross, R. R.

    2010-12-01

    Material irradiated by X-rays produces backscattered radiation which is commonly known as the Reflection Spectrum. It consists of a structured continuum, due at high energies to the competition between photoelectric absorption and electron scattering enhanced at low energies by emission from the material itself, together with a complex line spectrum. We briefly review the history of X-ray reflection in astronomy and discuss various methods for computing the reflection spectrum from cold and ionized gas, illustrated with results from our own work reflionx. We discuss how the reflection spectrum can be used to obtain the geometry of the accretion flow, particularly the inner regions around black holes and neutron stars.

  3. X-ray fluorescence experiment

    NASA Technical Reports Server (NTRS)

    Adler, I.; Trombka, J. I.; Gerard, J.; Schmadebeck, R.; Lowman, P.; Blodgett, H.; Yin, L.; Eller, E.; Lamothe, R.; Gorenstein, P.

    1972-01-01

    The preliminary results from the Sco X-1 and Cyg X-1 obtained from the Apollo 15 X-ray detector data are presented along with preliminary results of the X-ray fluorescence spectrometric data of the lunar surface composition. The production of the characteristic X-rays following the interaction of solar X-rays with the lunar surface is described along with the X-ray spectrometer. Preliminary analyses of the astronomical X-ray observation and the X-ray fluorescence data are presented.

  4. X-ray beam finder

    DOEpatents

    Gilbert, H.W.

    1983-06-16

    An X-ray beam finder for locating a focal spot of an X-ray tube includes a mass of X-ray opaque material having first and second axially-aligned, parallel-opposed faces connected by a plurality of substantially identical parallel holes perpendicular to the faces and a film holder for holding X-ray sensitive film tightly against one face while the other face is placed in contact with the window of an X-ray head.

  5. Risk estimates for meningiomas and other late effects after diagnostic X-ray exposure of the skull.

    PubMed

    Pflugbeil, S; Pflugbeil, C; Schmitz-Feuerhake, I

    2011-09-01

    This study aims to investigate the contribution of diagnostic exposures to the rising rates of brain tumours and other neoplasms which are observed in several industrial nations. Included are benign tumours in the head and neck region and cataracts which are neglected in usual risk estimates by international and national radiation protection committees. Dose-effect relationships for tumours of the brain, skin, thyroid and other sites of the head region, leukaemia and cataracts are taken from the literature. Risk estimates are derived for paediatric head computed tomographies (CTs) as well as for brain tumours in adults. On the basis of estimates for Germany about the number of head scans, the annual rate of radiation-induced diseases is calculated. About 1000 annual paediatric CT investigations of the skull will lead to about three excess neoplasms in the head region, i.e. the probability of an induced late effect must be suspected in the range of some thousands. Additionally, a relevant increase of cataracts must be considered. The radiation-induced occurrence of meningiomas and other brain tumours most probably contributes to the continuously increasing incidence of these diseases which is observed in several industrial nations, as well as the exposure of the bone marrow by CT to the increase of childhood leukaemia.

  6. Group-V atoms exchange due to exposure of InP surface to AsH3(+PH3) revealed by x-ray CTR scattering

    NASA Astrophysics Data System (ADS)

    Tabuchi, M.; Yamada, N.; Fujibayashi, K.; Takeda, Y.; Kamei, H.

    1996-05-01

    We conducted x-ray crystal truncation rod (CTR) measurements using synchro-tron radiation to analyze the As atom distribution in InP to the order of 1 ML. The InP samples which were only exposed to AsH3(+PH3) and capped by InP were investigated to study the effect of the purge sequence. The purge sequence is unavoidable to grow heteroepitaxial layers by OMVPE and is considered to affect largely the structure of the interface. From the results of the measurement and the computer simulation, the distribution of P and As atoms of the order of 1 ML was discussed as functions of the exposing time. It was shown that the number of As atoms contained in the samples saturated when the AsH3-exposure time is longer than 10 s. Comparing the profiles of AsH3-exposed samples with that of (AsH3 + PH3)-exposed samples, it was found that the As distribution in the buffer layer was suppressed in (AsH3 + PH3)-exposed samples. In order to obtain the sharp interfaces, the AsH3-exposure time must be shorter than 0.5 s.

  7. Neck x-ray

    MedlinePlus

    ... look at cervical vertebrae. These are the 7 bones of the spine in the neck. ... A neck x-ray can detect: Bone joint that is out of position (dislocation) Breathing in a foreign object Broken bone (fracture) Disk problems (disks ...

  8. Extremity x-ray

    MedlinePlus

    ... this test if you have signs of: A fracture Tumor Arthritis (inflammation of the joints) Normal Results The x-ray shows normal structures for the age of the person. What Abnormal Results Mean ... bone (fracture) Dislocated bone Osteomyelitis (infection) Arthritis Other conditions for ...

  9. Lethal and teratogenic effects after exposure to X-rays at various times of early murine gestation

    SciTech Connect

    Mueller, W.U.S.; Streffer, C.

    1990-12-01

    Various well-defined stages during completion of the second meiotic division and early organogenesis of mouse embryos were X-irradiated with doses of 1-4 Gy (100-400 rad). The major risk was prenatal mortality with radiation sensitivity changing markedly with dependence on the developmental stage irradiated; in the case of day 1 even within hours. The surviving fetuses did show a significantly enhanced frequency of malformations on day 19 of gestation (mostly gastroschisis and some exencephalies). This was true for all stages between days 1 and 8; only sensitivity again changed considerably. The radiation doses used in this study are markedly higher than doses that can be expected from radiation diagnostics, but exposure is in a range comparable to doses that can occur in radiation therapy (e.g., Morbus Hodgkin).

  10. Prenatal pesticide exposure and PON1 genotype associated with adolescent body fat distribution evaluated by dual X-ray absorptiometry (DXA).

    PubMed

    Tinggaard, J; Wohlfahrt-Veje, C; Husby, S; Christiansen, L; Skakkebaek, N E; Jensen, T K; Grandjean, P; Main, K M; Andersen, H R

    2016-07-01

    Many modern pesticides have endocrine disrupting abilities and early-life exposure may affect growth and disease risk later in life. Previously, we reported associations between prenatal pesticide exposure and higher childhood body fat content measured by anthropometry. The associations were affected by child PON1 Q192R genotype. We aimed to study whether prenatal pesticide exposure was still associated with body fat content and distribution in the children at puberty and the potential impact of both maternal and child PON1 Q192R genotype. In this prospective cohort study of 247 children born by occupationally exposed or unexposed women (greenhouse workers and controls) two follow-up examinations (age 10-15 and 11-16 years) including simple anthropometry, skinfold measurements, pubertal staging and blood sampling were performed. Total and regional fat% was determined by dual X-ray absorptiometry (DXA) at age 10-15. Prenatal pesticide exposure was associated with increased total, android, and gynoid fat percentage (DXA) at age 10-15 years after adjustment for sex, socioeconomic status, and puberty (all β = 0.5 standard deviation score (SDS) p < 0.05). Stratified by sex, the associations were significant in girls (total fat: β = 0.7 SDS, android-gynoid ratio: β = 0.1, both p < 0.05), but not in boys. Carrying the R-allele (child or mother, separately, or both) augmented the differences between exposed and unexposed children (total fat: β = 1.0 SDS, β = 0.8 SDS, p < 0.05, respectively, and β = 1.2 SDS, p < 0.01). No exposure-related differences were found if either the child or mother had the QQ wild-type. At age 11-16, exposed children tended to have a higher total fat% estimated by skinfolds than unexposed children (p = 0.06). No significant associations between prenatal exposure and body mass index or waist circumference were found. Prenatal pesticide exposure was associated with higher adolescent body fat content, including android

  11. X-Rays from Saturn and its Rings

    NASA Technical Reports Server (NTRS)

    Bhardwaj, Anil; Elsner, Ron F.; Waite, J. Hunter; Gladstone, G. Randall; Cravens, Tom E.; Ford, Peter G.

    2005-01-01

    In January 2004 Saturn was observed by Chandra ACIS-S in two exposures, 00:06 to 11:00 UT on 20 January and 14:32 UT on 26 January to 01:13 UT on 27 January. Each continuous observation lasted for about one full Saturn rotation. These observations detected an X-ray flare from the Saturn's disk and indicate that the entire Saturnian X-ray emission is highly variable -- a factor of $\\sim$4 variability in brightness in a week time. The Saturn X-ray flare has a time and magnitude matching feature with the solar X-ray flare, which suggests that the disk X-ray emission of Saturn is governed by processes happening on the Sun. These observations also unambiguously detected X-rays from Saturn's rings. The X-ray emissions from rings are present mainly in the 0.45-0.6 keV band centered on the atomic OK$\\alpha$ fluorescence line at 525 eV: indicating the production of X-rays due to oxygen atoms in the water icy rings. The characteristics of X-rays from Saturn's polar region appear to be statistically consistent with those from its disk X-rays, suggesting that X-ray emission from the polar cap region might be an extension of the Saturn disk X-ray emission.

  12. X-Rays from Saturn and its Rings

    NASA Technical Reports Server (NTRS)

    Bhardwaj, Anil; Elsner, Ron F.; Waite, J. Hunter; Gladstone, G. Randall; Cravens, Tom E.; Ford, Peter G.

    2005-01-01

    In January 2004 Saturn was observed by Chandra ACIS-S in two exposures, 00:06 to 11:00 UT on 20 January and 14:32 UT on 26 January to 01:13 UT on 27 January. Each continuous observation lasted for about one full Saturn rotation. These observations detected an X-ray flare from the Saturn's disk and indicate that the entire Saturnian X-ray emission is highly variable -- a factor of $\\sim$4 variability in brightness in a week time. The Saturn X-ray flare has a time and magnitude matching feature with the solar X-ray flare, which suggests that the disk X-ray emission of Saturn is governed by processes happening on the Sun. These observations also unambiguously detected X-rays from Saturn's rings. The X-ray emissions from rings are present mainly in the 0.45-0.6 keV band centered on the atomic OK$\\alpha$ fluorescence line at 525 eV: indicating the production of X-rays due to oxygen atoms in the water icy rings. The characteristics of X-rays from Saturn's polar region appear to be statistically consistent with those from its disk X-rays, suggesting that X-ray emission from the polar cap region might be an extension of the Saturn disk X-ray emission.

  13. X-ray magnetic resonance fusion modality may reduce radiation exposure and contrast dose in diagnostic cardiac catheterization of congenital heart disease.

    PubMed

    Abu Hazeem, Anas A; Dori, Yoav; Whitehead, Kevin K; Harris, Matthew A; Fogel, Mark A; Gillespie, Matthew J; Rome, Jonathan J; Glatz, Andrew C

    2014-11-01

    Radiation exposure in the pediatric population may increase the risk of future malignancy. Children with congenital heart disease who often undergo repeated catheterizations are at risk. One possible strategy to reduce radiation is to use X-ray Magnetic Resonance Fusion (XMRF) to facilitate cardiac catheterization. Catheterization data of patients who underwent diagnostic XMRF procedures between January 1, 2009 and February 1, 2012 were reviewed. Cases were matched 1:1 to contemporary controls who did not undergo XMRF based on weight and diagnosis and were compared in radiation exposure, contrast dose, and procedural and anesthesia times. Forty-four matched pairs were included. Baseline demographics were similar in both groups. Patients in the XMRF group had lower indices of radiation exposure measured by fluoroscopy time (14 vs. 16.4 vs. P = 0.047), dose-area product from fluoroscopy (513.2 vs. 589.1 µGy·m(2) , P = 0.042), total dose-area product (625.8 vs. 995.2 µGy·m(2) , P = 0.027), and total air kerma dose (94.5 vs. 153.8 mGy, P = 0.017). There was also a significant reduction in contrast dose (2 vs. 3.3 cc/kg, P <0.001). Procedural time tended to be shorter in the XMRF group but anesthesia time was significantly longer. Select diagnostic cardiac catheterization cases that utilized XMRF used less radiation and contrast than similar cases where XMRF was not used. Future work is needed to determine whether similar benefits can be extended to other types of diagnostic and complex interventional procedures. © 2014 Wiley Periodicals, Inc.

  14. Changes in X-ray sensitivity and glutathione content of human colon tumor cells after exposure to the differentiation-inducing agent sodium butyrate

    SciTech Connect

    Leith, J.T.; Hallows, K.T.; Arundel, C.M.; Bliven, S.F.

    1988-06-01

    Clone A human colon cancer cells were exposed to concentrations of sodium butyrate (NAB, 0-2 mM) for three passages in vitro, and responses to either graded single doses or split doses of 250 kVp X rays were determined. The survival data were fit to the single-hit, multitarget model of inactivation. For the graded single dose experiments, we found that NAB produced a decrease in the magnitude of the quasi-threshold (Dq) parameter after a concentration of about 0.9 mM was exceeded. Similarly, in split dose experiments, the amount of sublethal damage recovery (SLDR) was reduced in a concentration-dependent manner as shown by a decrease in the Dq parameter. However, the inhibition of SLDR occurred with no apparent threshold NAB concentration. NAB did not affect potentially lethal damage recovery. Paradoxically, increasing concentrations of NAB produced an exponential increase in the intracellular glutathione content, which could be blocked by exposure of the cells to buthionine sulfoximine (BSO). BSO treatment of NAB-adapted cells led to additional cell killing, again most noted by changes in the Dq parameter. We postulate that these responses are associated with NAB-induced changes in chromatin structure, particularly the association between DNA and nucleosomal histones H3 and H4.

  15. An innovative a-Si:H p-i-n based X-ray medical image detector for low dosage and long exposure applications

    NASA Astrophysics Data System (ADS)

    Fann, Sen-Shyong; Jiang, Yeu-Long; Hwang, Huey-Liang

    2003-05-01

    An innovative hydrogenated amorphous silicon (a-Si:H) p-i-n photodiode based X-ray detector for medical imaging applications was developed in this work, and the improvements of the device were also discussed. The detector consists of an a-Si:H p-i-n photodiode and a stacked dielectric layer, such as silicon nitride (SiN x), deposited on p-layer of this p-i-n diode (n-i-p-SiN x), as the major charge storage element. The detector operates as a capacitor, formed by this dielectric layer, in parallel with a reverse-biased p-i-n diode during the detection cycle. Consequently, the capacitance, for accumulating the photon-converted charges, of the p-i-n diode was enlarged by this stacked dielectric layer without decreasing the active area of the detector. As a result, the dynamic range, linearity and data retention capability of this novel detector are significantly improved. In particular, the photo sensitivity and charge storage capability of this novel detector can be separately optimized, and the drastically improved data retention, due to the high density and long release time of the trapped electrons in p-layer of the p-i-n diode, could facilitate this novel detector to be employed in the low dosage flux and long exposure applications.

  16. Characteristic X-ray Generator Utilizing Angle Dependence of Bremsstrahlung X-ray Distribution

    NASA Astrophysics Data System (ADS)

    Sato, Eiichi; Tanaka, Etsuro; Mori, Hidezo; Kawai, Toshiaki; Inoue, Takashi; Ogawa, Akira; Sato, Shigehiro; Takayama, Kazuyoshi; Onagawa, Jun

    2006-04-01

    This generator consists of the following components: a constant high-voltage power supply, a filament power supply, a turbomolecular pump, and an X-ray tube. The X-ray tube is a demountable diode which is connected to the turbomolecular pump and consists of the following major devices: a molybdenum rod target, a tungsten hairpin cathode (filament), a focusing (Wehnelt) electrode, a polyethylene terephthalate X-ray window 0.25 mm in thickness, and a stainless-steel tube body. In the X-ray tube, the positive high voltage is applied to the anode (target) electrode, and the cathode is connected to the tube body (ground potential). In this experiment, the tube voltage applied was from 22 to 36 kV, and the tube current was regulated to within 100 μA by the filament temperature. The exposure time is controlled in order to obtain optimum X-ray intensity. The electron beams from the cathode are converged to the target by the focusing electrode, and clean K-series characteristic X-rays are produced through the focusing electrode without using a filter. The X-ray intensity was 26.6 μGy/s at 1.0 m from the X-ray source with a tube voltage of 30 kV and a tube current of 100 μA, and quasi-monochromatic radiography was performed using a computed radiography system.

  17. Planetary X ray experiment

    NASA Technical Reports Server (NTRS)

    Anderson, K. A.

    1972-01-01

    Design studies for an X-ray experiment using solid state detectors and for an experiment using a proportional counter for investigating Jovian and Saturnian magnetospheres are reported. Background counting rates through the forward aperture and leakage fluxes are discussed for each design. It is concluded that the best choice of instrument appears to have following the characteristics: (1) two separate multiwire proportional counters for redundancy; (2) passive collimation to restrict the field to about 5 deg, wiregrid modulation collimation to about 0.1 deg angular resolution; (3) no active shielding system around the counter body; and (4) light passive shielding around any portion of the counter body exposed to space to absorb most of the cosmic X-ray background.

  18. New intraoral x-ray fluorographic imaging for dentistry

    SciTech Connect

    Higashi, T.; Osada, T.; Aoyama, W.; Iguchi, M.; Suzuki, S.; Kanno, M.; Moriya, K.; Yoshimura, M.; Tusuda, M.

    1983-06-01

    A new dental x-ray fluorographic unit has been developed. This unit is composed of small intraoral x-ray tube, a compact x-ray image intensifier, and a high-resolution TV system. The purposes for developing this equipment were to (1) directly observe the tooth during endodontic procedures and (2) reduce x-ray exposure to the patient and the dentist. The radiation exposure can be reduced to about 1/600 the exposure used with conventional dental film. In clinical trials, a satisfactory fluorographic dental image for endodontic treatment was obtained with this new device.

  19. X-ray Spectrometer

    NASA Technical Reports Server (NTRS)

    Porter, F. Scott

    2004-01-01

    The X-ray Spectrometer (XRS) instrument is a revolutionary non-dispersive spectrometer that will form the basis for the Astro-E2 observatory to be launched in 2005. We have recently installed a flight spare X R S microcalorimeter spectrometer at the EBIT-I facility at LLNL replacing the XRS from the earlier Astro-E mission and providing twice the resolution. The X R S microcalorimeter is an x-ray detector that senses the heat deposited by the incident photon. It achieves a high energy resolution by operating at 0.06K and by carefully controlling the heat capacity and thermal conductance. The XRS/EBIT instrument has 32 pixels in a square geometry and achieves an energy resolution of 6 eV at 6 keV, with a bandpass from 0.1 to 12 keV (or more at higher operating temperature). The instrument allows detailed studies of the x-ray line emission of laboratory plasmas. The XRS/EBIT also provides an extensive calibration "library" for the Astro-E2 observatory.

  20. X-Ray Vision

    NASA Technical Reports Server (NTRS)

    Ramsey, B. D.; Elsner, R. F.; Engelhaupt, D.; Kolodziejczak, J. J.; ODell, S. L.; Speegle, C. O.; Weisskopf, M. C.

    2004-01-01

    We are fabricating optics for the hard-x-ray region using electroless nickel replication. The attraction of this process, which has been widely used elsewhere, is that the resulting full shell optics are inherently stable and thus can have very good angular resolution. The challenge with this process is to develop lightweight optics (nickel has a relatively high density of 8.9 g/cu cm), and to keep down the costs of mandrel fabrication. We accomplished the former through the development of high-strength nickel alloys that permit very thin shells without fabrication- and handling-induced deformations. For the latter, we have utilized inexpensive grinding and diamond turning to figure the mandrels and then purpose-built polishing machines to finish the surface. In-house plating tanks and a simple water-bath separation system complete the process. To date we have built shells ranging in size from 5 cm diameter to 50 cm, and with thickness down to 100 micron. For our HERO balloon program, we are fabricating over 200 iridium-coated shells, 250 microns thick, for hard-x-ray imaging up to 75 keV. Early test results on these have indicated half-power-diameters of 15 arcsec. The status of these and other hard-x-ray optics will be reviewed.

  1. X-Ray Vision

    NASA Technical Reports Server (NTRS)

    Ramsey, B. D.; Elsner, R. F.; Engelhaupt, D.; Kolodziejczak, J. J.; ODell, S. L.; Speegle, C. O.; Weisskopf, M. C.

    2004-01-01

    We are fabricating optics for the hard-x-ray region using electroless nickel replication. The attraction of this process, which has been widely used elsewhere, is that the resulting full shell optics are inherently stable and thus can have very good angular resolution. The challenge with this process is to develop lightweight optics (nickel has a relatively high density of 8.9 g/cu cm), and to keep down the costs of mandrel fabrication. We accomplished the former through the development of high-strength nickel alloys that permit very thin shells without fabrication- and handling-induced deformations. For the latter, we have utilized inexpensive grinding and diamond turning to figure the mandrels and then purpose-built polishing machines to finish the surface. In-house plating tanks and a simple water-bath separation system complete the process. To date we have built shells ranging in size from 5 cm diameter to 50 cm, and with thickness down to 100 micron. For our HERO balloon program, we are fabricating over 200 iridium-coated shells, 250 microns thick, for hard-x-ray imaging up to 75 keV. Early test results on these have indicated half-power-diameters of 15 arcsec. The status of these and other hard-x-ray optics will be reviewed.

  2. X-ray Spectrometer

    NASA Technical Reports Server (NTRS)

    Porter, F. Scott

    2004-01-01

    The X-ray Spectrometer (XRS) instrument is a revolutionary non-dispersive spectrometer that will form the basis for the Astro-E2 observatory to be launched in 2005. We have recently installed a flight spare X R S microcalorimeter spectrometer at the EBIT-I facility at LLNL replacing the XRS from the earlier Astro-E mission and providing twice the resolution. The X R S microcalorimeter is an x-ray detector that senses the heat deposited by the incident photon. It achieves a high energy resolution by operating at 0.06K and by carefully controlling the heat capacity and thermal conductance. The XRS/EBIT instrument has 32 pixels in a square geometry and achieves an energy resolution of 6 eV at 6 keV, with a bandpass from 0.1 to 12 keV (or more at higher operating temperature). The instrument allows detailed studies of the x-ray line emission of laboratory plasmas. The XRS/EBIT also provides an extensive calibration "library" for the Astro-E2 observatory.

  3. X-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    Wu, S. T.

    2000-01-01

    Dr. S. N. Zhang has lead a seven member group (Dr. Yuxin Feng, Mr. XuejunSun, Mr. Yongzhong Chen, Mr. Jun Lin, Mr. Yangsen Yao, and Ms. Xiaoling Zhang). This group has carried out the following activities: continued data analysis from space astrophysical missions CGRO, RXTE, ASCA and Chandra. Significant scientific results have been produced as results of their work. They discovered the three-layered accretion disk structure around black holes in X-ray binaries; their paper on this discovery is to appear in the prestigious Science magazine. They have also developed a new method for energy spectral analysis of black hole X-ray binaries; four papers on this topics were presented at the most recent Atlanta AAS meeting. They have also carried Monte-Carlo simulations of X-ray detectors, in support to the hardware development efforts at Marshall Space Flight Center (MSFC). These computation-intensive simulations have been carried out entirely on the computers at UAH. They have also carried out extensive simulations for astrophysical applications, taking advantage of the Monte-Carlo simulation codes developed previously at MSFC and further improved at UAH for detector simulations. One refereed paper and one contribution to conference proceedings have been resulted from this effort.

  4. X-ray lithography masking

    NASA Technical Reports Server (NTRS)

    Smith, Henry I. (Inventor); Lim, Michael (Inventor); Carter, James (Inventor); Schattenburg, Mark (Inventor)

    1998-01-01

    X-ray masking apparatus includes a frame having a supporting rim surrounding an x-ray transparent region, a thin membrane of hard inorganic x-ray transparent material attached at its periphery to the supporting rim covering the x-ray transparent region and a layer of x-ray opaque material on the thin membrane inside the x-ray transparent region arranged in a pattern to selectively transmit x-ray energy entering the x-ray transparent region through the membrane to a predetermined image plane separated from the layer by the thin membrane. A method of making the masking apparatus includes depositing back and front layers of hard inorganic x-ray transparent material on front and back surfaces of a substrate, depositing back and front layers of reinforcing material on the back and front layers, respectively, of the hard inorganic x-ray transparent material, removing the material including at least a portion of the substrate and the back layers of an inside region adjacent to the front layer of hard inorganic x-ray transparent material, removing a portion of the front layer of reinforcing material opposite the inside region to expose the surface of the front layer of hard inorganic x-ray transparent material separated from the inside region by the latter front layer, and depositing a layer of x-ray opaque material on the surface of the latter front layer adjacent to the inside region.

  5. X-ray exposure hazards for physicians performing ablation procedures and device implantation: results of the European Heart Rhythm Association survey.

    PubMed

    Marinskis, Germanas; Bongiorni, Maria Grazia; Dagres, Nikolaos; Lewalter, Thorsten; Pison, Laurent; Blomstrom-Lundqvist, Carina

    2013-03-01

    The purpose of the survey was to evaluate physician's and authorities policies and clinical practices when using occupational X-ray during ablation procedures and device implantation. This survey shows infrequent use of lead gloves, radiation absorbing pads, and lead glass cabins, but increasing use of three-dimensional mapping systems to decrease X-ray radiation hazards. Digital fluoroscopy with decreased frame rate is not used by approximately one-third of responding centres.

  6. Monitoring X-Ray Emission from X-Ray Bursters

    NASA Technical Reports Server (NTRS)

    Kaaret, Philip

    1998-01-01

    The goal of this investigation was to use the All-Sky Monitor on the Rossi X-Ray Timing Explorer (RXTE) in combination with the Burst and Transient Source Experiment on the Compton Gamma-Ray Observatory to simultaneously measure the x-ray (2-12 keV) and hard x-ray (20-100 keV) emission from x-ray bursters. The investigation was successful. We made the first simultaneous measurement of hard and soft x-ray emission and found a strong anticorrelation of hard and soft x-ray emission from the X-Ray Burster 4U 0614+091. The monitoring performed under this investigation was also important in triggering target of opportunity observations of x-ray bursters made under the investigation hard x-ray emission of x-ray bursters approved for RXTE cycles 1 and 2. These observations lead to a number of papers on high-frequency quasi-periodic oscillations and on hard x-ray emission from the x-ray bursters 4U 0614+091 and 4U 1705-44.

  7. Duodenal crypt health following exposure to Cr(VI): Micronucleus scoring, γ-H2AX immunostaining, and synchrotron X-ray fluorescence microscopy

    SciTech Connect

    Thompson, Chad M.; Wolf, Jeffrey C.; Elbekai, Reem H.; Paranjpe, Madhav G.; Seiter, Jennifer M.; Chappell, Mark A.; Tappero, Ryan V.; Suh, Mina; Proctor, Deborah M.; Bichteler, Anne; Haws, Laurie C.; Harris, Mark A.

    2015-08-01

    Lifetime exposure to high concentrations of hexavalent chromium [Cr(VI)] in drinking water results in intestinal damage and an increase in duodenal tumors in B6C3F1 mice. To assess whether these tumors could be the result of a direct mutagenic or genotoxic mode of action, we conducted a GLP-compliant 7-day drinking water study to assess crypt health along the entire length of the duodenum. Mice were exposed to water (vehicle control), 1.4, 21, or 180 ppm Cr(VI) via drinking water for 7 consecutive days. Crypt enterocytes in Swiss roll sections were scored as normal, mitotic, apoptotic, karyorrhectic, or as having micronuclei. A single oral gavage of 50 mg/kg cyclophosphamide served as a positive control for micronucleus induction. Exposure to 21 and 180 ppm Cr(VI) significantly increased the number of crypt enterocytes. Micronuclei and γ-H2AX immunostaining were not elevated in the crypts of Cr(VI)-treated mice. In contrast, treatment with cyclophosphamide significantly increased numbers of crypt micronuclei and qualitatively increased γ-H2AX immunostaining. Synchrotron-based X-ray fluorescence (XRF) microscopy revealed the presence of strong Cr fluorescence in duodenal villi, but negligible Cr fluorescence in the crypt compartment. Together, these data indicate that Cr(VI) does not adversely effect the crypt compartment where intestinal stem cells reside, and provide additional evidence that the mode of action for Cr(VI)-induced intestinal cancer in B6C3F1 mice involves chronic villous wounding resulting in compensatory crypt enterocyte hyperplasia.

  8. Panoramic Dental X-Ray

    MedlinePlus

    ... Physician Resources Professions Site Index A-Z Panoramic Dental X-ray Panoramic dental x-ray uses a ... Your e-mail address: Personal message (optional): Bees: Wax: Notice: RadiologyInfo respects your privacy. Information entered here ...

  9. Soft X-ray Imaging

    SciTech Connect

    Seely, John

    1999-05-20

    The contents of this report cover the following: (1) design of the soft x-ray telescope; (2) fabrication and characterization of the soft x-ray telescope; and (3) experimental implementation at the OMEGA laser facility.

  10. Fluctuation X-Ray Scattering

    SciTech Connect

    Saldin, PI: D. K.; Co-I's: J. C. H. Spence and P. Fromme

    2013-01-25

    The work supported by the grant was aimed at developing novel methods of finding the structures of biomolecules using x-rays from novel sources such as the x-ray free electron laser and modern synchrotrons

  11. Encapsulating X-Ray Detectors

    NASA Technical Reports Server (NTRS)

    Conley, Joseph M.; Bradley, James G.

    1987-01-01

    Vapor-deposited polymer shields crystals from environment while allowing X rays to pass. Polymer coating transparental to X rays applied to mercuric iodide detector in partial vacuum. Coating protects crystal from sublimation, chemical attack, and electrical degradation.

  12. Dual X-ray absorptiometry

    NASA Astrophysics Data System (ADS)

    Altman, Albert; Aaron, Ronald

    2012-07-01

    Dual X-ray absorptiometry is widely used in analyzing body composition and imaging. Both the method and its limitations are related to the Compton and photoelectric contributions to the X-ray attenuation coefficients of materials.

  13. X-ray safety at the Los Alamos National Laboratory

    SciTech Connect

    Gutierrez, J.A.

    1986-11-01

    An organized and structured safety program for x-ray generating devices was initiated in October, 1979. An X-ray Device Control Office was established to manage the program that currently oversees the activities of 201 x-ray generating devices and to provide SOP reviews, perform shielding calculations, and provide training for both the operators and health physics x-ray device surveyors. The new program also establishes controls for procurement of new equipment, requires the writing of Standard Operating Procedures, requires training for operators and provides routine and non-routine safety inspections of x-ray generating devices. Prior to this program going into effect, the Laboratory had recorded nine documented x-ray related exposure accidents. Since then, there have been none. Program elements and experiences of interest to other x-ray device users are discussed. 3 refs.

  14. X-Ray Exam: Foot

    MedlinePlus

    ... Habits for TV, Video Games, and the Internet X-Ray Exam: Foot KidsHealth > For Parents > X-Ray Exam: Foot Print A A A What's in ... You Have Questions What It Is A foot X-ray is a safe and painless test that uses ...

  15. X-Ray Exam: Wrist

    MedlinePlus

    ... Habits for TV, Video Games, and the Internet X-Ray Exam: Wrist KidsHealth > For Parents > X-Ray Exam: Wrist Print A A A What's in ... You Have Questions What It Is A wrist X-ray is a safe and painless test that uses ...

  16. X-Ray Exam: Ankle

    MedlinePlus

    ... Habits for TV, Video Games, and the Internet X-Ray Exam: Ankle KidsHealth > For Parents > X-Ray Exam: Ankle Print A A A What's in ... You Have Questions What It Is An ankle X-ray is a safe and painless test that uses ...

  17. X-Ray Exam: Finger

    MedlinePlus

    ... Habits for TV, Video Games, and the Internet X-Ray Exam: Finger KidsHealth > For Parents > X-Ray Exam: Finger Print A A A What's in ... You Have Questions What It Is A finger X-ray is a safe and painless test that uses ...

  18. X-Ray Exam: Pelvis

    MedlinePlus

    ... Habits for TV, Video Games, and the Internet X-Ray Exam: Pelvis KidsHealth > For Parents > X-Ray Exam: Pelvis Print A A A What's in ... You Have Questions What It Is A pelvis X-ray is a safe and painless test that uses ...

  19. X-Ray Exam: Forearm

    MedlinePlus

    ... Habits for TV, Video Games, and the Internet X-Ray Exam: Forearm KidsHealth > For Parents > X-Ray Exam: Forearm Print A A A What's in ... You Have Questions What It Is A forearm X-ray is a safe and painless test that uses ...

  20. Tunable X-ray source

    DOEpatents

    Boyce, James R [Williamsburg, VA

    2011-02-08

    A method for the production of X-ray bunches tunable in both time and energy level by generating multiple photon, X-ray, beams through the use of Thomson scattering. The method of the present invention simultaneously produces two X-ray pulses that are tunable in energy and/or time.

  1. X-Ray Exam: Hip

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old X-Ray Exam: Hip KidsHealth > For Parents > X-Ray Exam: Hip A A A What's in this ... español Radiografía: cadera What It Is A hip X-ray is a safe and painless test that uses ...

  2. X-Ray Exam: Wrist

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old X-Ray Exam: Wrist KidsHealth > For Parents > X-Ray Exam: Wrist A A A What's in this ... español Radiografía: muñeca What It Is A wrist X-ray is a safe and painless test that uses ...

  3. X-Ray Exam: Ankle

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old X-Ray Exam: Ankle KidsHealth > For Parents > X-Ray Exam: Ankle A A A What's in this ... español Radiografía: tobillo What It Is An ankle X-ray is a safe and painless test that uses ...

  4. X-Ray Exam: Foot

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old X-Ray Exam: Foot KidsHealth > For Parents > X-Ray Exam: Foot A A A What's in this ... español Radiografía: pie What It Is A foot X-ray is a safe and painless test that uses ...

  5. Effect of Age at Exposure on the Incidence of Lung and Mammary Cancer after Thoracic X-Ray Irradiation in Wistar Rats.

    PubMed

    Yamada, Yutaka; Iwata, Ken-Ichi; Blyth, Benjamin J; Doi, Kazutaka; Morioka, Takamitsu; Daino, Kazuhiro; Nishimura, Mayumi; Kakinuma, Shizuko; Shimada, Yoshiya

    2017-02-01

    Epidemiology studies have shown that children are at greater overall risk of radiation-induced cancer, but the modifying effect of age at exposure in different tissues is heterogeneous. Early epidemiology findings of increased lung cancer risk with increasing age at the time of exposure have been dismissed, with suggestions that the trend is an artefact from a failure to adequately correct for the effects of tobacco smoking. Yet, differing models used in subsequent analyses have shown that the increased susceptibility with age, counter to the overall solid tumor trend, can either be confirmed or discounted depending on the model parameters used. In this study, we analyzed the induction of tumors in female Wistar rats exposed to increasing thoracic doses of X-ray as neonates, juveniles or young adults, to allow the effect of age at exposure in this early period to be observed in the absence of any interactions with smoking. Histology was used to compare tumor subtypes among groups, and genomic DNA copy number alterations in a number of tumors arising after irradiation at different ages were examined. Induction of lung cancers increased with radiation dose, with the frequency of early occurring lung adenomas greater in rats irradiated at older ages. At the highest dose, the rats irradiated at 5 or 15 weeks of age showed increased age-specific rates of lung adenocarcinomas in later life compared to those irradiated at 1 week of age. However, thoracic mammary gland tumors induced by the highest dose at the later ages significantly decreased the lifespan in these groups, reducing the number of rats at risk of radiation-induced lung adenocarcinoma. There was no induction of mammary tumors outside of the irradiated field. Lung adenocarcinomas showed widespread DNA copy number aberrations at the chromosome level, but the only recurrent lesions were intragenic Fhit deletions and losses on chromosome 4. The results presented here suggest that the risk of radiation

  6. SMM x ray polychromator

    NASA Technical Reports Server (NTRS)

    Saba, J. L. R.

    1993-01-01

    The objective of the X-ray Polychromator (XRP) experiment was to study the physical properties of solar flare plasma and its relation to the parent active region to understand better the flare mechanism and related solar activity. Observations were made to determine the temperature, density, and dynamic structure of the pre-flare and flare plasma as a function of wavelength, space and time, the extent to which the flare plasma departs from thermal equilibrium, and the variation of this departure with time. The experiment also determines the temperature and density structure of active regions and flare-induced changes in the regions.

  7. X-ray satellite

    NASA Technical Reports Server (NTRS)

    1985-01-01

    An overview of the second quarter 1985 development of the X-ray satellite project is presented. It is shown that the project is proceeding according to plan and that the projected launch date of September 9, 1987 is on schedule. An overview of the work completed and underway on the systems, subsystems, payload, assembly, ground equipment and interfaces is presented. Problem areas shown include cost increases in the area of focal instrumentation, the star sensor light scattering requirements, and postponements in the data transmission subsystems.

  8. X-ray lithography source

    DOEpatents

    Piestrup, Melvin A.; Boyers, David G.; Pincus, Cary

    1991-01-01

    A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits. Foil stacks are bombarded with a high-energy electron beam of 25 to 250 MeV to produce a flux of soft X-rays of 500 eV to 3 keV. Methods of increasing the total X-ray power and making the cross section of the X-ray beam uniform are described. Methods of obtaining the desired X-ray-beam field size, optimum frequency spectrum and elminating the neutron flux are all described. A method of obtaining a plurality of station operation is also described which makes the process more efficient and economical. The satisfying of these issues makes transition radiation an exellent moderate-priced X-ray source for lithography.

  9. X-ray lithography source

    DOEpatents

    Piestrup, M.A.; Boyers, D.G.; Pincus, C.

    1991-12-31

    A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits is disclosed. Foil stacks are bombarded with a high-energy electron beam of 25 to 250 MeV to produce a flux of soft X-rays of 500 eV to 3 keV. Methods of increasing the total X-ray power and making the cross section of the X-ray beam uniform are described. Methods of obtaining the desired X-ray-beam field size, optimum frequency spectrum and eliminating the neutron flux are all described. A method of obtaining a plurality of station operation is also described which makes the process more efficient and economical. The satisfying of these issues makes transition radiation an excellent moderate-priced X-ray source for lithography. 26 figures.

  10. Monochromatic x-ray generator utilizing angle dependence of bremsstrahlung x-ray distribution

    NASA Astrophysics Data System (ADS)

    Sato, Eiichi; Tanaka, Etsuro; Mori, Hidezo; Kawai, Toshiaki; Inoue, Takashi; Ogawa, Akira; Ichimaru, Toshio; Takayama, Kazuyoshi; Ido, Hideaki

    2005-08-01

    This generator consists of the following components: a constant high-voltage power supply, a filament power supply, a turbomolecular pump, and an x-ray tube. The x-ray tube is a demountable diode which is connected to the turbomolecular pump and consists of the following major devices: a molybdenum rod target, a tungsten hairpin cathode (filament), a focusing (Wehnelt) electrode, a polyethylene terephthalate x-ray window 0.25 mm in thickness, and a stainless-steel tube body. In the x-ray tube, the positive high voltage is applied to the anode (target) electrode, and the cathode is connected to the tube body (ground potential). In this experiment, the tube voltage applied was from 22 to 36 kV, and the tube current was regulated to within 100 μA by the filament temperature. The exposure time is controlled in order to obtain optimum x-ray intensity. The electron beams from the cathode are converged to the target by the focusing electrode, and clean Kα rays are produced through the focusing electrode using a 20-μm-thick zirconium filter. The x-ray intensity was 12.1 μGy/s at 1.0 m from the x-ray source with a tube voltage of 30 kV and a tube current of 100 μA, and monochromatic radiography was performed using a computed radiography system.

  11. Process and device for x-ray system quality assurance

    SciTech Connect

    Van Pelt, W.F.; Peterson, R.W.

    1982-11-10

    This invention relates to medical radiography test systems, and more particularly to a method and apparatus for providing evaluation of a medical or dental x-ray system consisting of x-ray generator, film and processor on a daily basis and to thereby assure the production of useful radiographs from the system with no need to repeat patient exposure because of problems with the x-ray system.

  12. Assessment of Personal Airborne Exposures and Surface Contamination from X-ray Vaporization of Beryllium Targets at the National Ignition Facility.

    PubMed

    Paik, Samuel Y; Epperson, Patrick M; Kasper, Kenneth M

    2017-02-28

    This study presents air and surface sampling data collected over the first two years since beryllium was introduced as a target material at the National Ignition Facility. Over this time, 101 experiments with beryllium-containing targets were executed. The data provides an assessment of current conditions in the facility and a baseline for future impacts as new, reduced regulatory limits for beryllium are being proposed by both the Occupational Safety and Health Administration and Department of Energy. This study also investigates how beryllium deposits onto exposed surfaces as a result of x-ray vaporization and the effectiveness of simple decontamination measures in reducing the amount of removable beryllium from a surface. Based on 1,961 surface wipe samples collected from entrant components (equipment directly exposed to target debris) and their surrounding work areas during routine reconfiguration activities, only one result was above the beryllium release limit of 0.2 μg/100 cm(2) and 27 results were above the analytical reporting limit of 0.01 μg/100 cm(2), for a beryllium detection rate of 1.4%. Surface wipe samples collected from the internal walls of the NIF target chamber, however, showed higher levels of beryllium, with beryllium detected on 73% and 87% of the samples during the first and second target chamber entries (performed annually), respectively, with 23% of the samples above the beryllium release limit during the second target chamber entry. The analysis of a target chamber wall panel exposed during the first 30 beryllium-containing experiments (cumulatively) indicated that 87% of the beryllium contamination remains fixed onto the surface after wet wiping the surface and 92% of the non-fixed contamination was removed by decontaminating the surface using a dry wipe followed by a wet wipe. Personal airborne exposures assessed during access to entrant components and during target chamber entry indicated that airborne beryllium was not present

  13. Assessment of personal airborne exposures and surface contamination from x-ray vaporization of beryllium targets at the National Ignition Facility

    DOE PAGES

    Paik, Samuel Y.; Epperson, Patrick M.; Kasper, Kenneth M.

    2017-02-28

    Here, this article presents air and surface sampling data collected over the first two years since beryllium was introduced as a target material at the National Ignition Facility. Over this time, 101 experiments with beryllium-containing targets were executed. The data provides an assessment of current conditions in the facility and a baseline for future impacts as new, reduced regulatory limits for beryllium are being proposed by both the Occupational Safety and Health Administration and Department of Energy. This study also investigates how beryllium deposits onto exposed surfaces as a result of x-ray vaporization and the effectiveness of simple decontamination measuresmore » in reducing the amount of removable beryllium from a surface. Based on 1,961 surface wipe samples collected from entrant components (equipment directly exposed to target debris) and their surrounding work areas during routine reconfiguration activities, only one result was above the beryllium release limit of 0.2 µg/100 cm2 and 27 results were above the analytical reporting limit of 0.01 µg/100 cm2, for a beryllium detection rate of 1.4%. Surface wipe samples collected from the internal walls of the NIF target chamber, however, showed higher levels of beryllium, with beryllium detected on 73% and 87% of the samples during the first and second target chamber entries (performed annually), respectively, with 23% of the samples above the beryllium release limit during the second target chamber entry. The analysis of a target chamber wall panel exposed during the first 30 beryllium-containing experiments (cumulatively) indicated that 87% of the beryllium contamination remains fixed onto the surface after wet wiping the surface and 92% of the non-fixed contamination was removed by decontaminating the surface using a dry wipe followed by a wet wipe. Personal airborne exposures assessed during access to entrant components and during target chamber entry indicated that airborne beryllium was not

  14. Association between leukaemia and X-ray in children: a nationwide study.

    PubMed

    Shih, Tian-Yu; Wu, Jay; Muo, Chin-Shin; Kao, Chia-Hung

    2014-08-01

    The frequency of employing radiography is increasing. Long-term risks of performing X-ray procedures on children and adolescents for medical diagnosis have raised significant concerns. In this study, we adopt the case-control methodology to evaluate the relationship between the incidence rate of acute leukaemia and exposure to radiation during diagnostic X-ray examinations for children. Based on 1998-2010 data obtained from the Taiwan Bureau of National Health Insurance database, we selected 58 children with leukaemia and randomly selected an additional 232 children as the control group. The mean age of children with leukaemia is 8.92 ± 5.24 years. The risk of leukaemia in children who underwent X-ray examinations increased 2.14-fold (95% CI, 1.18-3.87). In this study, we identified that, when undergoing X-ray examinations, the risk of leukaemia in children increased for both sex and age groups. Specifically, the relationship between leukaemia and X-ray in boys (OR = 3.28, 95%CI, 1.33-8.07) and in ages of 6 to 11 years (OR = 2.58, 95%CI, 1.09-6.10) was significant. Overall, the risk of leukaemia in children who underwent X-ray examinations progressively increased from a ratio of 1.65 to 3.14. Moreover, an identical trend was observed for boys (1.85 to 6.42). Exposure to X-ray increased the risk of leukaemia in children. © 2014 The Authors. Journal of Paediatrics and Child Health © 2014 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

  15. Hard X-Ray Emission of X-Ray Bursters

    NASA Technical Reports Server (NTRS)

    Kaaret, P.

    1999-01-01

    The primary goal of this proposal was to perform an accurate measurement of the broadband x-ray spectrum of a neutron-star low-mass x-ray binary found in a hard x-ray state. This goal was accomplished using data obtained under another proposal, which has provided exciting new information on the hard x-ray emission of neutron-star low-mass x-ray binaries. In "BeppoSAX Observations of the Atoll X-Ray Binary 4U0614+091", we present our analysis of the spectrum of 4U0614+091 over the energy band from 0.3-150 keV. Our data confirm the presence of a hard x-ray tail that can be modeled as thermal Comptonization of low-energy photons on electrons having a very high temperature, greater than 220 keV, or as a non-thermal powerlaw. Such a very hard x-ray spectrum has not been previously seen from neutron-star low-mass x-ray binaries. We also detected a spectral feature that can be interpreted as reprocessing, via Compton reflection, of the direct emission by an optically-thick disk and found a correlation between the photon index of the power-law tail and the fraction of radiation reflected which is similar to the correlation found for black hole candidate x-ray binaries and Seyfert galaxies. A secondary goal was to measure the timing properties of the x-ray emission from neutronstar low-mass x-ray binaries in their low/hard states.

  16. The EOS 2D/3D X-ray imaging system: a cost-effectiveness analysis quantifying the health benefits from reduced radiation exposure.

    PubMed

    Faria, Rita; McKenna, Claire; Wade, Ros; Yang, Huiqin; Woolacott, Nerys; Sculpher, Mark

    2013-08-01

    To evaluate the cost-effectiveness of the EOS(®) 2D/3D X-ray imaging system compared with standard X-ray for the diagnosis and monitoring of orthopaedic conditions. A decision analytic model was developed to quantify the long-term costs and health outcomes, expressed as quality-adjusted life years (QALYs) from the UK health service perspective. Input parameters were obtained from medical literature, previously developed cancer models and expert advice. Threshold analysis was used to quantify the additional health benefits required, over and above those associated with radiation-induced cancers, for EOS(®) to be considered cost-effective. Standard X-ray is associated with a maximum health loss of 0.001 QALYs, approximately 0.4 of a day in full health, while the loss with EOS(®) is a maximum of 0.00015 QALYs, or 0.05 of a day in full health. On a per patient basis, EOS(®) is more expensive than standard X-ray by between £10.66 and £224.74 depending on the assumptions employed. The results suggest that EOS(®) is not cost-effective for any indication. Health benefits over and above those obtained from lower radiation would need to double for EOS to be considered cost-effective. No evidence currently exists on whether there are health benefits associated with imaging improvements from the use of EOS(®). The health benefits from radiation dose reductions are very small. Unless EOS(®) can generate additional health benefits as a consequence of the nature and quality of the image, comparative patient throughput with X-ray will be the major determinant of cost-effectiveness. Crown Copyright © 2013. Published by Elsevier Ireland Ltd. All rights reserved.

  17. Miniature x-ray source

    DOEpatents

    Trebes, James E.; Stone, Gary F.; Bell, Perry M.; Robinson, Ronald B.; Chornenky, Victor I.

    2002-01-01

    A miniature x-ray source capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature x-ray source comprises a compact vacuum tube assembly containing a cathode, an anode, a high voltage feedthru for delivering high voltage to the anode, a getter for maintaining high vacuum, a connection for an initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is highly x-ray transparent and made, for example, from boron nitride. The compact size and potential for remote operation allows the x-ray source, for example, to be placed adjacent to a material sample undergoing analysis or in proximity to the region to be treated for medical applications.

  18. British X-ray astronomy

    NASA Astrophysics Data System (ADS)

    Pounds, K. A.

    1986-09-01

    The development of solar and cosmic X-ray studies in the UK, in particular the Skylark and Ariel programs, is discussed. The characteristics and capabilities of the X-ray emulsion detector developed to monitor the solar X-radiation in the Skylark program, and of the proportional counter spectrometer developed for solar X-ray measurements on the Ariel I satellite are described. The designs and functions of the pin-hole camera, the Bragg crystal spectrometer, and the X-ray spectroheliograph are exmained. The Skylark observations of cosmic X-ray sources and high-resolution solar spectra, and the Ariel 5 data on cosmic X-ray sources are presented. Consideration is given to the Ariel 6, the U.S. Einstein Observatory, Exosat, and ASTRO-C.

  19. Solar X-ray physics

    SciTech Connect

    Bornmann, P.L. )

    1991-01-01

    Research on solar X-ray phenomena performed by American scientists during 1987-1990 is reviewed. Major topics discussed include solar images observed during quiescent times, the processes observed during solar flares, and the coronal, interplanetary, and terrestrial phenomena associated with solar X-ray flares. Particular attention is given to the hard X-ray emission observed at the start of the flare, the energy transfer to the soft X-ray emitting plasma, the late resolution of the flare as observed in soft X-ray, and the rate of occurrence of solar flares as a function of time and latitude. Pertinent aspects of nonflaring, coronal X-ray emission and stellar flares are also discussed. 175 refs.

  20. Stability issues of the use of coherent x-rays

    NASA Astrophysics Data System (ADS)

    Nishino, Yoshinori; Kudo, Togo; Suzuki, Motohiro; Ishikawa, Tetsuya

    2003-12-01

    The stability of synchrotron beamline optics is required in experiments using x-ray coherence. Especially the stability of a monochromator is important in considering a high heat load due to exposure to intense polychromatic x-rays. We developed MOSTAB (monochromator stabilization) modules and carried out performance tests using SPring-8 beamlines. We succeeded in the simultaneous stabilization of the monochromatic x-ray beam intensity and position with MOSTAB. An attempt was also made to stabilize the x-ray beam at the 1 km experimental station at SPring-8.

  1. X-ray induced demagnetization of single-molecule magnets

    SciTech Connect

    Dreiser, Jan; Westerström, Rasmus; Piamonteze, Cinthia; Nolting, Frithjof; Rusponi, Stefano; Brune, Harald; Yang, Shangfeng; Popov, Alexey; Dunsch, Lothar; Greber, Thomas

    2014-07-21

    Low-temperature x-ray magnetic circular dichroism measurements on the endohedral single-molecule magnet DySc{sub 2}N@C{sub 80} at the Dy M{sub 4,5} edges reveal a shrinking of the opening of the observed hysteresis with increasing x-ray flux. Time-dependent measurements show that the exposure of the molecules to x-rays resonant with the Dy M{sub 5} edge accelerates the relaxation of magnetization more than off-resonant x-rays. The results cannot be explained by a homogeneous temperature rise due to x-ray absorption. Moreover, the observed large demagnetization cross sections indicate that the resonant absorption of one x-ray photon induces the demagnetization of many molecules.

  2. X-Ray Polarization Imaging

    DTIC Science & Technology

    2006-07-01

    anatomic structures. Johns and Yaffe (2), building on the work of Alvarez and Macovski (3) and that of Lehmann et al (4), discuss a method for...sources of contrast related to both the wave and par- ticulate nature of x rays. References 1. Johns PC, Yaffe MJ. X-ray characterization of normal and...application to mammography. Med Phys 1985; 12:289–296. 3. Alvarez RE, Macovski A. Energy-selective reconstructions in x-ray computerized tomography. Phys

  3. Topological X-Rays Revisited

    ERIC Educational Resources Information Center

    Lynch, Mark

    2012-01-01

    We continue our study of topological X-rays begun in Lynch ["Topological X-rays and MRI's," iJMEST 33(3) (2002), pp. 389-392]. We modify our definition of a topological magnetic resonance imaging and give an affirmative answer to the question posed there: Can we identify a closed set in a box by defining X-rays to probe the interior and without…

  4. Topological X-Rays Revisited

    ERIC Educational Resources Information Center

    Lynch, Mark

    2012-01-01

    We continue our study of topological X-rays begun in Lynch ["Topological X-rays and MRI's," iJMEST 33(3) (2002), pp. 389-392]. We modify our definition of a topological magnetic resonance imaging and give an affirmative answer to the question posed there: Can we identify a closed set in a box by defining X-rays to probe the interior and without…

  5. X-ray Absorption Spectroscopy

    SciTech Connect

    Yano, Junko; Yachandra, Vittal K.

    2009-07-09

    This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

  6. Deep x-ray lithography based processing for micromechanics

    SciTech Connect

    Christenson, T.R.

    1995-10-01

    Deep x-ray lithography based fabrication provides a means to fabricate microactuators with useful output forces. High energy x-ray exposure provides a tool for fabrication of the next generation of precision engineered components. Device characterization, materials science, an metrology continue to pose challenges at this scale.

  7. X-ray photonics: Bending X-rays with nanochannels

    NASA Astrophysics Data System (ADS)

    Pelliccia, Daniele

    2016-02-01

    X-ray counterparts of visible light optical elements are notoriously difficult to realize because the refractive index of all materials is close to unity. It has now been demonstrated that curved waveguides fabricated on a silicon chip can channel and deflect X-ray beams by consecutive grazing reflections.

  8. Cell cycle tracking for irradiated and unirradiated bystander cells in a single colony with exposure to a soft X-ray microbeam.

    PubMed

    Kaminaga, Kiichi; Noguchi, Miho; Narita, Ayumi; Hattori, Yuya; Usami, Noriko; Yokoya, Akinari

    2016-11-01

    To establish a new experimental technique to explore the photoelectric and subsequent Auger effects on the cell cycles of soft X-ray microbeam-irradiated cells and unirradiated bystander cells in a single colony. Several cells located in the center of a microcolony of HeLa-Fucci cells consisting of 20-80 cells were irradiated with soft X-ray (5.35 keV) microbeam using synchrotron radiation as a light source. All cells in the colony were tracked for 72 h by time-lapse microscopy imaging. Cell cycle progression, division, and death of each cell in the movies obtained were analyzed by pedigree assay. The number of cell divisions in the microcolony was also determined. The fates of these cells were clarified by tracking both irradiated and unirradiated bystander cells. Irradiated cells showed significant cell cycle retardation, explosive cell death, or cell fusion after a few divisions. These serious effects were also observed in 15 and 26% of the bystander cells for 10 and 20 Gy irradiation, respectively, and frequently appeared in at least two daughter or granddaughter cells from a single-parent cell. We successfully tracked the fates of microbeam-irradiated cells and unirradiated bystander cells with live cell recordings, which have revealed the dynamics of soft X-ray irradiated and unirradiated bystander cells for the first time. Notably, cell deaths or cell cycle arrests frequently arose in closely related cells. These details would not have been revealed by a conventional immunostaining imaging method. Our approach promises to reveal the dynamic cellular effects of soft X-ray microbeam irradiation and subsequent Auger processes from various endpoints in future studies.

  9. X-ray based extensometry

    NASA Technical Reports Server (NTRS)

    Jordan, E. H.; Pease, D. M.

    1988-01-01

    A totally new method of extensometry using an X-ray beam was proposed. The intent of the method is to provide a non-contacting technique that is immune to problems associated with density variations in gaseous environments that plague optical methods. X-rays are virtually unrefractable even by solids. The new method utilizes X-ray induced X-ray fluorescence or X-ray induced optical fluorescence of targets that have melting temperatures of over 3000 F. Many different variations of the basic approaches are possible. In the year completed, preliminary experiments were completed which strongly suggest that the method is feasible. The X-ray induced optical fluorescence method appears to be limited to temperatures below roughly 1600 F because of the overwhelming thermal optical radiation. The X-ray induced X-ray fluorescence scheme appears feasible up to very high temperatures. In this system there will be an unknown tradeoff between frequency response, cost, and accuracy. The exact tradeoff can only be estimated. It appears that for thermomechanical tests with cycle times on the order of minutes a very reasonable system may be feasible. The intended applications involve very high temperatures in both materials testing and monitoring component testing. Gas turbine engines, rocket engines, and hypersonic vehicles (NASP) all involve measurement needs that could partially be met by the proposed technology.

  10. Astronomical X-Ray Optics

    NASA Technical Reports Server (NTRS)

    Joy, M. K.

    2000-01-01

    Over the past two decades, grazing incidence optics have transformed observational x-ray astronomy into a major scientific discipline at the cutting edge of research in astrophysics and cosmology. This review summarizes the fundamental design principles of grazing incidence optics for astronomical applications, describes the capabilities of the current generation of x-ray telescopes, and explores several avenues of future development.

  11. Dual x-ray absorptiometry

    NASA Astrophysics Data System (ADS)

    Altman, Albert; Aaron, Ronald

    2011-04-01

    Dual x-ray absorptiometry is widely used in analyzing body composition and imaging. We discuss the physics of the method and exhibit its limitations and show it is related to the Compton and photoelectric contributions to the x-ray absorption coefficients of materials.

  12. X-ray position detector

    NASA Technical Reports Server (NTRS)

    Garmire, G. (Inventor)

    1972-01-01

    An X-ray position detector for real time operation is described. A set of proportional counters is arranged into an array which can detect and indicate the position of an X-ray interaction within the array, in the X Y plane.

  13. Real-Time, Light Weight, X-Ray Imager. Phase 2

    DTIC Science & Technology

    1994-06-06

    Lght Weight, X-Ray Imager"I Principle hwvesdgatow Eiren Kutlubay Miderm Report Table of Contents Front Cover Report Dcm taonpage Foreword 1...of the system to an X-ray exposure. Lanex screens will be used for the initial tests. Phantoms will be available to be used under X-ray exposure

  14. X-ray shearing interferometer

    DOEpatents

    Koch, Jeffrey A [Livermore, CA

    2003-07-08

    An x-ray interferometer for analyzing high density plasmas and optically opaque materials includes a point-like x-ray source for providing a broadband x-ray source. The x-rays are directed through a target material and then are reflected by a high-quality ellipsoidally-bent imaging crystal to a diffraction grating disposed at 1.times. magnification. A spherically-bent imaging crystal is employed when the x-rays that are incident on the crystal surface are normal to that surface. The diffraction grating produces multiple beams which interfere with one another to produce an interference pattern which contains information about the target. A detector is disposed at the position of the image of the target produced by the interfering beams.

  15. X-Ray Tomographic Reconstruction

    SciTech Connect

    Bonnie Schmittberger

    2010-08-25

    Tomographic scans have revolutionized imaging techniques used in medical and biological research by resolving individual sample slices instead of several superimposed images that are obtained from regular x-ray scans. X-Ray fluorescence computed tomography, a more specific tomography technique, bombards the sample with synchrotron x-rays and detects the fluorescent photons emitted from the sample. However, since x-rays are attenuated as they pass through the sample, tomographic scans often produce images with erroneous low densities in areas where the x-rays have already passed through most of the sample. To correct for this and correctly reconstruct the data in order to obtain the most accurate images, a program employing iterative methods based on the inverse Radon transform was written. Applying this reconstruction method to a tomographic image recovered some of the lost densities, providing a more accurate image from which element concentrations and internal structure can be determined.

  16. X-Ray Diffraction Apparatus

    NASA Technical Reports Server (NTRS)

    Blake, David F. (Inventor); Bryson, Charles (Inventor); Freund, Friedmann (Inventor)

    1996-01-01

    An x-ray diffraction apparatus for use in analyzing the x-ray diffraction pattern of a sample is introduced. The apparatus includes a beam source for generating a collimated x-ray beam having one or more discrete x-ray energies, a holder for holding the sample to be analyzed in the path of the beam, and a charge-coupled device having an array of pixels for detecting, in one or more selected photon energy ranges, x-ray diffraction photons produced by irradiating such a sample with said beam. The CCD is coupled to an output unit which receives input information relating to the energies of photons striking each pixel in the CCD, and constructs the diffraction pattern of photons within a selected energy range striking the CCD.

  17. Focusing X-Ray Telescopes

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen; Brissenden, Roger; Davis, William; Elsner, Ronald; Elvis, Martin; Freeman, Mark; Gaetz, Terrance; Gorenstein, Paul; Gubarev, Mikhall; Jerlus, Diab; hide

    2010-01-01

    During the half-century history of x-ray astronomy, focusing x-ray telescopes, through increased effective area and finer angular resolution, have improved sensitivity by 8 orders of magnitude. Here, we review previous and current x-ray-telescope missions. Next, we describe the planned next-generation x-ray-astronomy facility, the International X-ray Observatory (IXO). We conclude with an overview of a concept for the next next-generation facility, Generation X. Its scientific objectives will require very large areas (about 10,000 sq m) of highly-nested, lightweight grazing-incidence mirrors, with exceptional (about 0.1-arcsec) resolution. Achieving this angular resolution with lightweight mirrors will likely require on-orbit adjustment of alignment and figure.

  18. Refractive Optics for Hard X-ray Transmission Microscopy

    SciTech Connect

    Simon, M.; Last, A.; Mohr, J.; Nazmov, V.; Reznikova, E.; Ahrens, G.; Voigt, A.

    2011-09-09

    For hard x-ray transmission microscopy at photon energies higher than 15 keV we design refractive condenser and imaging elements to be used with synchrotron light sources as well as with x-ray tube sources. The condenser lenses are optimized for low x-ray attenuation--resulting in apertures greater than 1 mm--and homogeneous intensity distribution on the detector plane, whereas the imaging enables high-resolution (<100 nm) full-field imaging. To obtain high image quality at reasonable exposure times, custom-tailored matched pairs of condenser and imaging lenses are being developed. The imaging lenses (compound refractive lenses, CRLs) are made of SU-8 negative resist by deep x-ray lithography. SU-8 shows high radiation stability. The fabrication technique enables high-quality lens structures regarding surface roughness and arrangement precision with arbitrary 2D geometry. To provide point foci, crossed pairs of lenses are used. Condenser lenses have been made utilizing deep x-ray lithographic patterning of thick SU-8 layers, too, whereas in this case, the aperture is limited due to process restrictions. Thus, in terms of large apertures, condenser lenses made of structured and rolled polyimide film are more attractive. Both condenser types, x-ray mosaic lenses and rolled x-ray prism lenses (RXPLs), are considered to be implemented into a microscope setup. The x-ray optical elements mentioned above are characterized with synchrotron radiation and x-ray laboratory sources, respectively.

  19. X-ray monitoring optical elements

    DOEpatents

    Stoupin, Stanislav; Shvydko, Yury; Katsoudas, John; Blank, Vladimir D.; Terentyev, Sergey A.

    2016-12-27

    An X-ray article and method for analyzing hard X-rays which have interacted with a test system. The X-ray article is operative to diffract or otherwise process X-rays from an input X-ray beam which have interacted with the test system and at the same time provide an electrical circuit adapted to collect photoelectrons emitted from an X-ray optical element of the X-ray article to analyze features of the test system.

  20. X-ray diagnostics for TFTR

    SciTech Connect

    von Goeler, S.; Hill, K.W.; Bitter, M.

    1982-12-01

    A short description of the x-ray diagnostic preparation for the TFTR tokamak is given. The x-ray equipment consists of the limiter x-ray monitoring system, the soft x-ray pulse-height-analysis-system, the soft x-ray imaging system and the x-ray crystal spectrometer. Particular attention is given to the radiation protection of the x-ray systems from the neutron environment.

  1. Frequency of acute myeloid leukaemia-associated mouse chromosome 2 deletions in X-ray exposed immature haematopoietic progenitors and stem cells☆

    PubMed Central

    Olme, C.-H.; Brown, N.; Finnon, R.; Bouffler, S.D.; Badie, C.

    2013-01-01

    Exposure to ionising radiation can lead to an increased risk of cancer, particularly leukaemia. In radiation-induced acute myeloid leukaemia (rAML), a partial hemizygous deletion of mouse chromosome 2 is a common feature in several susceptible strains. The deletion is an early event detectable 24 h after exposure in bone marrow cells using cytogenetic techniques. Expanding clones of bone marrow cells with chromosome 2 deletions can be detected less than a year after exposure to ionising radiation in around half of the irradiated mice. Ultimately, 15–25% of exposed animals develop AML. It is generally assumed that leukaemia originates in an early progenitor cell or haematopoietic stem cell, but it is unknown whether the original chromosome damage occurs at a similar frequency in committed progenitors and stem cells. In this study, we monitored the frequency of chromosome 2 deletions in immature bone marrow cells (Lin−) and haematopoietic stem cells/multipotent progenitor cells (LSK) by several techniques, fluorescent in situ hybridisation (FISH) and through use of a reporter gene model, flow cytometry and colony forming units in spleen (CFU-S) following ex vivo or in vivo exposure. We showed that partial chromosome 2 deletions are present in the LSK subpopulation, but cannot be detected in Lin− cells and CFU-S12 cells. Furthermore, we transplanted irradiated Lin− or LSK cells into host animals to determine whether specific irradiated cell populations acquire an increased proliferative advantage compared to unirradiated cells. Interestingly, the irradiated LSK subpopulation containing cells carrying chromosome 2 deletions does not appear to repopulate as well as the unirradiated population, suggesting that the chromosomal deletion does not provide an advantage for growth and in vivo repopulation, at least at early stages following occurrence. PMID:23665297

  2. X-Ray Imaging System

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The FluoroScan Imaging System is a high resolution, low radiation device for viewing stationary or moving objects. It resulted from NASA technology developed for x-ray astronomy and Goddard application to a low intensity x-ray imaging scope. FlouroScan Imaging Systems, Inc, (formerly HealthMate, Inc.), a NASA licensee, further refined the FluoroScan System. It is used for examining fractures, placement of catheters, and in veterinary medicine. Its major components include an x-ray generator, scintillator, visible light image intensifier and video display. It is small, light and maneuverable.

  3. X-Ray Imaging System

    NASA Astrophysics Data System (ADS)

    1986-01-01

    The FluoroScan Imaging System is a high resolution, low radiation device for viewing stationary or moving objects. It resulted from NASA technology developed for x-ray astronomy and Goddard application to a low intensity x-ray imaging scope. FlouroScan Imaging Systems, Inc, (formerly HealthMate, Inc.), a NASA licensee, further refined the FluoroScan System. It is used for examining fractures, placement of catheters, and in veterinary medicine. Its major components include an x-ray generator, scintillator, visible light image intensifier and video display. It is small, light and maneuverable.

  4. Dissociative X-ray Lasing

    NASA Astrophysics Data System (ADS)

    Miao, Q.; Liu, J.-C.; Ågren, H.; Rubensson, J.-E.; Gel'mukhanov, F.

    2012-12-01

    X-ray lasing is predicted to ensue when molecules are pumped into dissociative core-excited states by a free-electron-laser pulse. The lasing is due to the population inversion created in the neutral dissociation product, and the process features self-trapping of the x-ray pulse at the gain ridge. Simulations performed for the HCl molecule pumped at the 2p1/2→6σ resonance demonstrate that the scheme can be used to create ultrashort coherent x-ray pulses.

  5. X-RAY MONITORING OF ULTRALUMINOUS X-RAY SOURCES

    SciTech Connect

    Kaaret, Philip; Feng Hua

    2009-09-10

    X-ray monitoring observations were performed with the Swift observatory of the ultraluminous X-ray sources Holmberg IX X-1, NGC 5408 X-1, and NGC 4395 X-2 and also of the nuclear X-ray source in NGC 4395. Holmberg IX X-1 remains in the hard X-ray spectral state as its flux varies by a factor of 7 up to a (isotropic) luminosity of 2.8 x 10{sup 40} erg s{sup -1}. This behavior may suggest an unusually massive compact object. We find excess power at periods near 60 days and 28 days in the X-ray emission from Holmberg IX X-1. Additional monitoring is required to test the significance of these signals. NGC 5408 X-1 and NGC 4395 X-2 appear to remain in the soft spectral state found by Chandra and XMM with little variation in spectral hardness even as the luminosity changes by a factor of 9. We found an outburst from the nuclear source in NGC 4395 reaching an X-ray luminosity of 9 x 10{sup 40} erg s{sup -1}, several times higher than any previously reported.

  6. Re-refinement of 4g4a: room-temperature X-ray diffraction study of cisplatin and its binding to His15 of HEWL after 14 months chemical exposure in the presence of DMSO.

    PubMed

    Tanley, Simon W M; Schreurs, Antoine M M; Kroon-Batenburg, Loes M J; Helliwell, John R

    2016-03-01

    A re-refinement of 4g4a, the room-temperature X-ray diffraction study of cisplatin and its binding to His15 of HEWL after 14 months chemical exposure in the presence of DMSO is published as an addendum to Tanley et al. [(2012), Acta Cryst. F68, 1300-1306]. This example illustrates the benefits of sharing raw diffraction images, as well as structure factors and molecular coordinates, as the diffraction resolution of the study is now much improved at 1.70 Å.

  7. X-Ray Imaging Study

    NASA Technical Reports Server (NTRS)

    OBrien, Susan K.; Workman, Gary L.

    1996-01-01

    The space environment in which the Space Station Freedom and other space platforms will orbit is truly a hostile environment. For example, the currently estimated integral fluence for electrons above 1 Mev at 2000 nautical miles is above 2 x 1O(exp 10) electrons/sq cm/day and the proton integral fluence is above 1 x 10(exp 9) protons/sq cm/day. At the 200 - 400 nautical miles, which is more representative of the altitude which will provide the environment for the Space Station, each of these fluences will be proportionally less; however, the data indicates that the radiation environment will obviously have an effect on structural materials exposed to the environment for long durations. The effects of this combined environment is the issue which needs to be understood for the long term exposure of structures in space. At the same time, there will be substantial potential for collisions between the space platforms and space debris. The current NASA catalogue contains over 4500 objects floating in space which are not considered payloads. This debris can have significant effects on collision with orbiting spacecraft. In order to better understand the effect of these hostile phenomena on spacecraft, several types of studies are being performed to simulate at some level the effect of the environment. In particular the study of debris clouds produced by hypervelocity impact on the various surfaces anticipated on the Space Station is very important at this point in time. The need to assess the threat of such debris clouds on space structures is an on-going activity. The Space Debris Impact facility in Building 4612 provides a test facility to monitor the types of damage produced with hypervelocity impact. These facilities are used to simulate space environmental effects from energetic particles. Flash radiography or x-ray imaging has traditionally provided such information and as such has been an important tool for recording damage in situ with the event. The proper

  8. Severe Acute Respiratory Syndrome-Coronavirus Papain-Like Novel Protease Inhibitors: Design, Synthesis, Protein-Ligand X-ray Structure and Biological Evaluation

    SciTech Connect

    Ghosh, Arun K.; Takayama, Jun; Rao, Kalapala Venkateswar; Ratia, Kiira; Chaudhuri, Rima; Mulhearn, Debbie C.; Lee, Hyun; Nichols, Daniel B.; Baliji, Surendranath; Baker, Susan C.; Johnson, Michael E.; Mesecar, Andrew D.

    2012-02-21

    The design, synthesis, X-ray crystal structure, molecular modeling, and biological evaluation of a series of new generation SARS-CoV PLpro inhibitors are described. A new lead compound 3 (6577871) was identified via high-throughput screening of a diverse chemical library. Subsequently, we carried out lead optimization and structure-activity studies to provide a series of improved inhibitors that show potent PLpro inhibition and antiviral activity against SARS-CoV infected Vero E6 cells. Interestingly, the (S)-Me inhibitor 15h (enzyme IC{sub 50} = 0.56 {mu}M; antiviral EC{sub 50} = 9.1 {mu}M) and the corresponding (R)-Me 15g (IC{sub 50} = 0.32 {mu}M; antiviral EC{sub 50} = 9.1 {mu}M) are the most potent compounds in this series, with nearly equivalent enzymatic inhibition and antiviral activity. A protein-ligand X-ray structure of 15g-bound SARS-CoV PLpro and a corresponding model of 15h docked to PLpro provide intriguing molecular insight into the ligand-binding site interactions.

  9. Lumbosacral spine x-ray

    MedlinePlus

    ... should be taken before children receive x-rays. Considerations There are some back problems that an x- ... imaging for low back pain: advice for high-value health care from the American College of Physicians. ...

  10. Miniature x-ray source

    DOEpatents

    Trebes, James E.; Bell, Perry M.; Robinson, Ronald B.

    2000-01-01

    A miniature x-ray source utilizing a hot filament cathode. The source has a millimeter scale size and is capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature source consists of a compact vacuum tube assembly containing the hot filament cathode, an anode, a high voltage feedthru for delivering high voltage to the cathode, a getter for maintaining high vacuum, a connector for initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is fabricated from highly x-ray transparent materials, such as sapphire, diamond, or boron nitride.

  11. CELESTIAL X-RAY SOURCES.

    DTIC Science & Technology

    sources, (4) the physical conditions in the pulsating x-ray source in the Crab Nebula , and (5) miscellaneous related topics. A bibliography of all work performed under the contract is given. (Author)

  12. Nanoscale X-ray imaging

    NASA Astrophysics Data System (ADS)

    Sakdinawat, Anne; Attwood, David

    2010-12-01

    Recent years have seen significant progress in the field of soft- and hard-X-ray microscopy, both technically, through developments in source, optics and imaging methodologies, and also scientifically, through a wide range of applications. While an ever-growing community is pursuing the extensive applications of today's available X-ray tools, other groups are investigating improvements in techniques, including new optics, higher spatial resolutions, brighter compact sources and shorter-duration X-ray pulses. This Review covers recent work in the development of direct image-forming X-ray microscopy techniques and the relevant applications, including three-dimensional biological tomography, dynamical processes in magnetic nanostructures, chemical speciation studies, industrial applications related to solar cells and batteries, and studies of archaeological materials and historical works of art.

  13. Future x-ray missions

    NASA Astrophysics Data System (ADS)

    Mushotzky, Richard F.

    2002-11-01

    Recent results from XMM-Newton and Chandra show that sufficiently sensitive x_ray imaging and spectroscopic capabilities allow one to observe the evolution of active galaxies out to z ~ 6, the x-ray signature of luminous star forming galaxies at z~3, as well as the origin and evolution of cosmic structure. With the advent of new optical/UV/IR and radio capabilities in the next decade, it is appropriate to evaluate the future capabilities of planned x-ray missions (e.g., Constellation_X and Astro-E2) as well as other missions being developed (e.g., Gen-X, XEUS, and Astro-G) or under advance planning (MAXIM and EXIST). I will present a summary of the present status of the field and the capabilities of these missions for extragalactic x-ray astronomy.

  14. X-Ray Exam: Pelvis

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Your Child's Development (Birth to 3 Years) Feeding ... radiologist (a doctor who is specially trained in reading and interpreting X-ray images). The radiologist will ...

  15. X-Ray Exam: Forearm

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Your Child's Development (Birth to 3 Years) Feeding ... a radiologist (a doctor who's specially trained in reading and interpreting X-ray images). The radiologist will ...

  16. X-Ray Exam: Finger

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Your Child's Development (Birth to 3 Years) Feeding ... Results A radiologist, a doctor specially trained in reading and interpreting X-ray images, will look at ...

  17. Imaging X-ray spectrometer

    NASA Technical Reports Server (NTRS)

    Grant, P. A.; Jackson, J. W., Jr.; Alcorn, G. E.; Marshall, F. E. (Inventor)

    1984-01-01

    An X-ray spectrometer for providing imaging and energy resolution of an X-ray source is described. This spectrometer is comprised of a thick silicon wafer having an embedded matrix or grid of aluminum completely through the wafer fabricated, for example, by thermal migration. The aluminum matrix defines the walls of a rectangular array of silicon X-ray detector cells or pixels. A thermally diffused aluminum electrode is also formed centrally through each of the silicon cells with biasing means being connected to the aluminum cell walls and causes lateral charge carrier depletion between the cell walls so that incident X-ray energy causes a photoelectric reaction within the silicon producing collectible charge carriers in the form of electrons which are collected and used for imaging.

  18. X-ray microtomographic scanners

    SciTech Connect

    Syryamkin, V. I. Klestov, S. A.

    2015-11-17

    The article studies the operating procedures of an X-ray microtomographic scanner and the module of reconstruction and analysis 3D-image of a test sample in particular. An algorithm for 3D-image reconstruction based on image shadow projections and mathematical methods of the processing are described. Chapter 1 describes the basic principles of X-ray tomography and general procedures of the device developed. Chapters 2 and 3 are devoted to the problem of resources saving by the system during the X-ray tomography procedure, which is achieved by preprocessing of the initial shadow projections. Preprocessing includes background noise removing from the images, which reduces the amount of shadow projections in general and increases the efficiency of the group shadow projections compression. In conclusion, the main applications of X-ray tomography are presented.

  19. High Resolution X-ray-Induced Acoustic Tomography

    PubMed Central

    Xiang, Liangzhong; Tang, Shanshan; Ahmad, Moiz; Xing, Lei

    2016-01-01

    Absorption based CT imaging has been an invaluable tool in medical diagnosis, biology, and materials science. However, CT requires a large set of projection data and high radiation dose to achieve superior image quality. In this letter, we report a new imaging modality, X-ray Induced Acoustic Tomography (XACT), which takes advantages of high sensitivity to X-ray absorption and high ultrasonic resolution in a single modality. A single projection X-ray exposure is sufficient to generate acoustic signals in 3D space because the X-ray generated acoustic waves are of a spherical nature and propagate in all directions from their point of generation. We demonstrate the successful reconstruction of gold fiducial markers with a spatial resolution of about 350 μm. XACT reveals a new imaging mechanism and provides uncharted opportunities for structural determination with X-ray. PMID:27189746

  20. High Resolution X-ray-Induced Acoustic Tomography.

    PubMed

    Xiang, Liangzhong; Tang, Shanshan; Ahmad, Moiz; Xing, Lei

    2016-05-18

    Absorption based CT imaging has been an invaluable tool in medical diagnosis, biology, and materials science. However, CT requires a large set of projection data and high radiation dose to achieve superior image quality. In this letter, we report a new imaging modality, X-ray Induced Acoustic Tomography (XACT), which takes advantages of high sensitivity to X-ray absorption and high ultrasonic resolution in a single modality. A single projection X-ray exposure is sufficient to generate acoustic signals in 3D space because the X-ray generated acoustic waves are of a spherical nature and propagate in all directions from their point of generation. We demonstrate the successful reconstruction of gold fiducial markers with a spatial resolution of about 350 μm. XACT reveals a new imaging mechanism and provides uncharted opportunities for structural determination with X-ray.

  1. High Resolution X-ray-Induced Acoustic Tomography

    NASA Astrophysics Data System (ADS)

    Xiang, Liangzhong; Tang, Shanshan; Ahmad, Moiz; Xing, Lei

    2016-05-01

    Absorption based CT imaging has been an invaluable tool in medical diagnosis, biology, and materials science. However, CT requires a large set of projection data and high radiation dose to achieve superior image quality. In this letter, we report a new imaging modality, X-ray Induced Acoustic Tomography (XACT), which takes advantages of high sensitivity to X-ray absorption and high ultrasonic resolution in a single modality. A single projection X-ray exposure is sufficient to generate acoustic signals in 3D space because the X-ray generated acoustic waves are of a spherical nature and propagate in all directions from their point of generation. We demonstrate the successful reconstruction of gold fiducial markers with a spatial resolution of about 350 μm. XACT reveals a new imaging mechanism and provides uncharted opportunities for structural determination with X-ray.

  2. An X-ray diffraction and X-ray absorption spectroscopy joint study of neuroglobin.

    PubMed

    Arcovito, Alessandro; Moschetti, Tommaso; D'Angelo, Paola; Mancini, Giordano; Vallone, Beatrice; Brunori, Maurizio; Della Longa, Stefano

    2008-07-01

    Neuroglobin (Ngb) is a member of the globin family expressed in the vertebrate brain, involved in neuroprotection. A combined approach of X-ray diffraction (XRD) on single crystal and X-ray absorption spectroscopy (XAS) in solution, allows to determine the oxidation state and the structure of the Fe-heme both in the bis-histidine and the CO-bound (NgbCO) states. The overall data demonstrate that under X-ray the iron is photoreduced fairly rapidly, and that the previously reported X-ray structure of ferric Ngb [B. Vallone, K. Nienhaus, M. Brunori, G.U. Nienhaus, Proteins 56 (2004) 85-92] very likely refers to a photoreduced species indistinguishable from the dithionite reduced protein. Results from the XAS analysis of NgbCO in solution are in good agreement with XRD data on the crystal. However prolonged X-ray exposure at 15K determines CO release. This preliminary result paves the way to experiments aimed at the characterization of pentacoordinate ferrous Ngb, the only species competent in binding external ligands such as O2, CO or NO.

  3. X-ray astronomical spectroscopy

    NASA Technical Reports Server (NTRS)

    Holt, S. S.

    1980-01-01

    The current status of the X-ray spectroscopy of celestial X-ray sources, ranging from nearby stars to distant quasars, is reviewed. Particular emphasis is placed on the role of such spectroscopy as a useful and unique tool in the elucidation of the physical parameters of the sources. The spectroscopic analysis of degenerate and nondegenerate stellar systems, galactic clusters and active galactic nuclei, and supernova remnants is discussed.

  4. X-ray computed tomography

    NASA Astrophysics Data System (ADS)

    1993-05-01

    The primary advantage of the X-ray computed tomography (XRCT) NDE method is that features are not superposed in the image, thereby rendering them easier to interpret than radiographic projection images. Industrial XRCT systems, unlike medical diagnostic systems, have no size and dosage constraints; they are accordingly used for systems from the scale of gas turbine blades, with hundreds-of-kV energies, to those of the scale of ICBMs, requiring MV-level X-ray energies.

  5. Electromechanical x-ray generator

    DOEpatents

    Watson, Scott A; Platts, David; Sorensen, Eric B

    2016-05-03

    An electro-mechanical x-ray generator configured to obtain high-energy operation with favorable energy-weight scaling. The electro-mechanical x-ray generator may include a pair of capacitor plates. The capacitor plates may be charged to a predefined voltage and may be separated to generate higher voltages on the order of hundreds of kV in the AK gap. The high voltage may be generated in a vacuum tube.

  6. X-Ray Protection

    DTIC Science & Technology

    1955-01-01

    for example temporomandibular - joint exposures where a skin dose of 25 r or more may be obtained during a single exposure with 65 kvp, 1.5 mm aluminum...Movable barriers should not be depended upon for protection above 100 kv. 4.4. Surfaces of lead sheets at joints should be in contact, with a lap of at...equivalent of the seams is not less than the minimum requirement. (See chapter II.) *4.6. Joints between different kinds of protective materials

  7. Tokamak x ray diagnostic instrumentation

    SciTech Connect

    Hill, K.W.; Beiersdorfer, P.; Bitter, M.; Fredrickson, E.; Von Goeler, S.; Hsuan, H.; Johnson, L.C.; Liew, S.L.; McGuire, K.; Pare, V.

    1987-01-01

    Three classes of x-ray diagnostic instruments enable measurement of a variety of tokamak physics parameters from different features of the x-ray emission spectrum. (1) The soft x-ray (1 to 50 keV) pulse-height-analysis (PHA) diagnostic measures impurity concentrations from characteristic line intensities and the continuum enhancement, and measures the electron temperature from the continuum slope. (2) The Bragg x-ray crystal spectrometer (XCS) measures the ion temperature and neutral-beam-induced toroidal rotation velocity from the Doppler broadening and wavelength shift, respectively, of spectral lines of medium-Z impurity ions. Impurity charge state distributions, precise wavelengths, and inner-shell excitation and recombination rates can also be studied. X rays are diffracted and focused by a bent crystal onto a position-sensitive detector. The spectral resolving power E/..delta..E is greater than 10/sup 4/ and time resolution is 10 ms. (3) The x-ray imaging system (XIS) measures the spatial structure of rapid fluctuations (0.1 to 100 kHZ) providing information on MHD phenomena, impurity transport rates, toroidal rotation velocity, plasma position, and the electron temperature profile. It uses an array of silicon surface-barrier diodes which view different chords of the plasma through a common slot aperture and operate in current (as opposed to counting) mode. The effectiveness of shields to protect detectors from fusion-neutron radiation effects has been studied both theoretically and experimentally.

  8. Cosmic X-ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, D.; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1985-01-01

    A progress report of research activities carried out in the area of cosmic X-ray physics is presented. The Diffuse X-ray Spectrometer DXS which has been flown twice as a rocket payload is described. The observation times proved to be too small for meaningful X-ray data to be obtained. Data collection and reduction activities from the Ultra-Soft X-ray background (UXT) instrument are described. UXT consists of three mechanically-collimated X-ray gas proportional counters with window/filter combinations which allow measurements in three energy bands, Be (80-110 eV), B (90-187 eV), and O (e84-532 eV). The Be band measurements provide an important constraint on local absorption of X-rays from the hot component of the local interstellar medium. Work has also continued on the development of a calorimetric detector for high-resolution spectroscopy in the 0.1 keV - 8keV energy range.

  9. X-Rays, Pregnancy and You

    MedlinePlus

    ... and Procedures Medical Imaging Medical X-ray Imaging X-Rays, Pregnancy and You Share Tweet Linkedin Pin it ... the decision with your doctor. What Kind of X-Rays Can Affect the Unborn Child? During most x- ...

  10. Chandra X-Ray Sources in the LALA Cetus Field

    NASA Astrophysics Data System (ADS)

    Wang, J. X.; Zheng, Z. Y.; Malhotra, S.; Finkelstein, S. L.; Rhoads, J. E.; Norman, C. A.; Heckman, T. M.

    2007-11-01

    The 174 ks Chandra Advanced CCD Imaging Spectrometer exposure of the Large Area Lyman Alpha Survey (LALA) Cetus field is the second of the two deep Chandra images on LALA fields. In this paper we present the Chandra X-ray sources detected in the Cetus field, along with an analysis of X-ray source counts, stacked X-ray spectrum, and optical identifications. A total of 188 X-ray sources were detected: 174 in the 0.5-7.0 keV band, 154 in the 0.5-2.0 keV band, and 113 in the 2.0-7.0 keV band. The X-ray source counts were derived and compared with LALA field (172 ks exposure). Interestingly, we find consistent hard-band X-ray source density, but (36+/-12)% higher soft-band X-ray source density in Cetus field. The weighted stacked spectrum of the detected X-ray sources can be fitted by a power law with photon index Γ=1.55. Based on the weighted stacked spectrum, we find that the resolved fraction of the X-ray background drops from (72+/-1)% at 0.5-1.0 keV to (63+/-4)% at 6.0-8.0 keV. The unresolved spectrum can be fitted by a power law over the range 0.5-7 keV, with a photon index Γ=1.22. We also present optical counterparts for 154 of the X-ray sources, down to a limiting magnitude of r'=25.9 (Vega), using a deep r'-band image obtained with the MMT. Optical Observations reported here were obtained at the MMT Observatory, a joint facility of the University of Arizona and the Smithsonian Institution.

  11. Application of X-ray imaging techniques to auroral monitoring

    NASA Technical Reports Server (NTRS)

    Rust, D. M.; Burstein, P.

    1981-01-01

    The precipitation of energetic particles into the ionosphere produces bremsstrahlung X-rays and K-alpha line emission from excited oxygen and nitrogen. If viewed from a spacecraft in a highly elliptical polar orbit, this soft (0.3 - 3.0 keV) X-radiation will provide an almost uninterrupted record of dayside and nightside auroras. A grazing incidence X-ray telescope especially designed for such auroral monitoring is described. High photon collection efficiency will permit exposure times of approximately 100 seconds during substorms. Spectrophotometry will allow users to derive the energy spectrum of the precipitating particles. If placed in a 15 earth-radius orbit, the telescope can produce auroral X-ray images with 30 km resolution. Absolute position of X-ray auroras can be established with a small optical telescope co-aligned with the X-ray telescope. Comparison of X-ray and optical images will establish the height and global distribution of X-ray aurorae, relative to well-known optical auroras, thus melding the new X-ray results with knowledge of optical auroras.

  12. Two dimensional x-ray phase imaging using single grating interferometer with embedded x-ray targets.

    PubMed

    Morimoto, Naoki; Fujino, Sho; Yamazaki, Amane; Ito, Yasuhiro; Hosoi, Takuji; Watanabe, Heiji; Shimura, Takayoshi

    2015-06-29

    Using multidot metal targets embedded in a diamond substrate, we created a single-grating Talbot-Lau interferometer and used it to capture two dimensional (2D) x-ray phase images. The ensemble of these targets constitutes a tiny virtual array of x-ray source and enables x-ray phase-contrast imaging with no source or absorption grating within a 1 m source-detector distance for 8 keV x-rays. We directly resolved a dot-pattern self-image of the phase grating with 6 µm pitch by using an x-ray image detector with 24 µm pixels and obtained 2D differential-phase and dark-field images from a single-exposure. Using the 2D differential-phase images, we also obtained a phase image with no streak artifacts.

  13. Center for X-Ray Optics, 1992

    SciTech Connect

    Not Available

    1993-08-01

    This report discusses the following topics: Center for X-Ray Optics; Soft X-Ray Imaging wit Zone Plate Lenses; Biological X-Ray microscopy; Extreme Ultraviolet Lithography for Nanoelectronic Pattern Transfer; Multilayer Reflective Optics; EUV/Soft X-ray Reflectometer; Photoemission Microscopy with Reflective Optics; Spectroscopy with Soft X-Rays; Hard X-Ray Microprobe; Coronary Angiography; and Atomic Scattering Factors.

  14. Laboratory cryo soft X-ray microscopy.

    PubMed

    Hertz, H M; von Hofsten, O; Bertilson, M; Vogt, U; Holmberg, A; Reinspach, J; Martz, D; Selin, M; Christakou, A E; Jerlström-Hultqvist, J; Svärd, S

    2012-02-01

    Lens-based water-window X-ray microscopy allows two- and three-dimensional (2D and 3D) imaging of intact unstained cells in their near-native state with unprecedented contrast and resolution. Cryofixation is essential to avoid radiation damage to the sample. Present cryo X-ray microscopes rely on synchrotron radiation sources, thereby limiting the accessibility for a wider community of biologists. In the present paper we demonstrate water-window cryo X-ray microscopy with a laboratory-source-based arrangement. The microscope relies on a λ=2.48-nm liquid-jet high-brightness laser-plasma source, normal-incidence multilayer condenser optics, 30-nm zone-plate optics, and a cryo sample chamber. We demonstrate 2D imaging of test patterns, and intact unstained yeast, protozoan parasites and mammalian cells. Overview 3D information is obtained by stereo imaging while complete 3D microscopy is provided by full tomographic reconstruction. The laboratory microscope image quality approaches that of the synchrotron microscopes, but with longer exposure times. The experimental image quality is analyzed from a numerical wave-propagation model of the imaging system and a path to reach synchrotron-like exposure times in laboratory microscopy is outlined. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Medical x-ray photographic apparatus

    SciTech Connect

    Haneda, T.; Mukai, Y.

    1988-02-02

    This patent describes photo apparatus producing high definition photocopies from short video cameras exposures for diagnosing patients by copying a selected still image of a moving object by using a stored video frame signal selected from successive frames of the moving object obtained by a TV camera in a fixed position viewing the object, comprising: an x-ray generator for directing x-ray radiation through a patient under examination, and means for forming an image responsive to the x-ray radiation as viewed by the TV camera so that x-ray photo reproductions are reproduced with very little exposure time for the patient; first memory means for storing line components of a video signal respectively obtained by horizontally scanning the successive frames of the moving images of the object presented by the TV camera; display means including a TV display and means for reading out the line components of the video signal, successively at a first predetermined time interval and applying the read-out line components to the TV display for displaying the images of the object; means for selecting the line components of one frame of the video signal stored in the first memory means to represent a still image of the object when a desired image is viewed on the TV display; second memory means for reading out the fixed line components of the video signals frame obtained from the first memory means from stored lines of the selected frame successively at a second predetermined time interval, and storing each of the read-out line components until the next line component is read out, and means for copying on a recording medium a line image represented by input signals applied thereto.

  16. Ultrafast X-ray Sources

    SciTech Connect

    George Neil

    2010-04-19

    Since before the scattering of X-rays off of DNA led to the first understanding of the double helix structure, sources of X-rays have been an essential tool for scientists examining the structure and interactions of matter. The resolution of a microscope is proportional to the wavelength of light so x-rays can see much finer structures than visible light, down to single atoms. In addition, the energy of X-rays is resonant with the core atomic levels of atoms so with appropriate wavelengths the placement of specific atoms in a large molecule can be determined. Over 10,000 scientists use synchrotron sources, storage rings of high energy electrons, each year worldwide. As an example of such use, virtually every picture of a protein or drug molecule that one sees in the scientific press is a reconstruction based on X-ray scattering of synchrotron light from the crystallized form of that molecule. Unfortunately those pictures are static and proteins work through configuration (shape) changes in response to energy transfer. To understand how biological systems work requires following the energy flow to these molecules and tracking how shape changes drive their interaction with other molecules. We'd like to be able to freeze the action of these molecules at various steps along the way with an X-ray strobe light. How fast does it have to be? To actually get a picture of a molecule in a fixed configuration requires X-ray pulses as short as 30 femtoseconds (1/30 of a millionth of a millionth of a second). To capture the energy flow through changes in electronic levels requires a faster strobe, less than 1 femtosecond! And to acquire such information in smaller samples with higher accuracy demands brighter and brighter X-rays. Unfortunately modern synchrotrons (dubbed 3rd Generation Light Sources) cannot deliver such short bright pulses of X-rays. An entirely new approach is required, linear-accelerator (linac-)-based light sources termed 4th or Next Generation Light Sources

  17. Ultraluminous X-ray Sources.

    NASA Astrophysics Data System (ADS)

    Fabrika, S.; Sholukhova, O.; Abolmasov, P.

    2008-12-01

    We discuss a new type of X-ray sources discovered in galaxies -- ultraluminous X-ray sources (ULXs). They are of two order of magnitude brighter in X-rays than the brightest Galactic black holes. Two mod- els of ULXs are discussed: "intermediate mass" black holes, 100 - 10000 solar masses, with standard accretion disks, and "stellar mass" black holes with su- percritical accretion disks like that in the Galactic object SS 433. A study of gas nebulae surrounding these objects gives us a new important information on the central sources. The observed X-ray radiation of ULXs is not enough to power their nebulae. To understand both spectra and power of the nebulae one needs a powerful UV source. The ULXs must be such bright in UV range as they are in X-rays. Spectroscopy of gas filaments surrounding SS 433 proves that the intrinsic face-on luminosity of the supercritical accretion disk in the far UV region to be "sim; 10^40 erg/s. We expect that observations of ULXs with the WSO-UV Observatory, measurements their UV fluxes and spectral slopes solve the problem of ULXs between the two known models of these sources.

  18. X-rays surgical revolution.

    PubMed

    Toledo-Pereyra, Luis H

    2009-01-01

    Wilhelm Roentgen (1845-1923) created a surgical revolution with the discovery of the X-rays in late 1895 and the subsequent introduction of this technique for the management of surgical patients. No other physician or scientist had ever imagined such a powerful and worthwhile discovery. Other scientists paved the way for Roentgen to approach the use of these new X-rays for medical purposes. In this way, initially, and prior to Roentgen, Thompson, Hertz, and Lenard applied themselves to the early developments of this technology. They made good advances but never reached the clearly defined understanding brought about by Roentgen. The use of a Crookes tube, a barium platinocyanide screen, with fluorescent light and the generation of energy to propagate the cathode rays were the necessary elements for the conception of an X-ray picture. On November 8, 1895, Roentgen began his experiments on X-ray technology when he found that some kind of rays were being produced by the glass of the tube opposite to the cathode. The development of a photograph successfully completed this early imaging process. After six intense weeks of research, on December 22, he obtained a photograph of the hand of his wife, the first X-ray ever made. This would be a major contribution to the world of medicine and surgery.

  19. X-ray Echo Spectroscopy

    NASA Astrophysics Data System (ADS)

    Shvyd'ko, Yuri

    2016-02-01

    X-ray echo spectroscopy, a counterpart of neutron spin echo, is being introduced here to overcome limitations in spectral resolution and weak signals of the traditional inelastic x-ray scattering (IXS) probes. An image of a pointlike x-ray source is defocused by a dispersing system comprised of asymmetrically cut specially arranged Bragg diffracting crystals. The defocused image is refocused into a point (echo) in a time-reversal dispersing system. If the defocused beam is inelastically scattered from a sample, the echo signal acquires a spatial distribution, which is a map of the inelastic scattering spectrum. The spectral resolution of the echo spectroscopy does not rely on the monochromaticity of the x rays, ensuring strong signals along with a very high spectral resolution. Particular schemes of x-ray echo spectrometers for 0.1-0.02 meV ultrahigh-resolution IXS applications (resolving power >108 ) with broadband ≃5 - 13 meV dispersing systems are introduced featuring more than 103 signal enhancement. The technique is general, applicable in different photon frequency domains.

  20. Clocking Femtosecond X-Rays

    SciTech Connect

    Cavalieri, A L; Fritz, D M; Lee, S H; Bucksbaum, P H; Reis, D A; Mills, D M; Pahl, R; Rudati, J; Fuoss, P H; Stephenson, G B; Lowney, D P; MacPhee, A G; Weinstein, D; Falcone, R W; Als-Nielsen, J; Blome, C; Ischebeck, R; Schlarb, H; Tschentscher, T; Schneider, J; Sokolowski-Tinten, K; Chapman, H N; Lee, R W; Hansen, T N; Synnergren, O; Larsson, J; Techert, S; Sheppard, J; Wark, J S; Bergh, M; Calleman, C; Huldt, G; der Spoel, D v; Timneanu, N; Hajdu, J; Bong, E; Emma, P; Krejcik, P; Arthur, J; Brennan, S; Gaffney, K J; Lindenberg, A M; Hastings, J B

    2004-10-08

    The Sub-Picosecond Pulse Source (SPPS) at the Stanford Linear Accelerator Center (SLAC) produces the brightest ultrafast x-ray pulses in the world, and is the first to employ compressed femtosecond electron bunches for the x-ray source. Both SPPS and future X-ray Free Electron Lasers (XFEL's) will use precise measurements of individual electron bunches to time the arrival of x-ray pulses for time-resolved experiments. At SPPS we use electro-optic sampling (EOS) to perform these measurements. Here we present the first results using this method. An ultrafast laser pulse (135 fs) passes through an electro-optic crystal adjacent to the electron beam. The refractive index of the crystal is distorted by the strong electromagnetic fields of the ultra-relativistic electrons, and this transient birefringence is imprinted on the laser polarization. A polarizer decodes this signal, producing a time-dependent image of the compressed electron bunch. Our measurements yield the relative timing between an ultrafast optical laser and an ultrafast x-ray pulse to within 60 fs, making it possible to use the SPPS to observe atomic-scale ultrafast dynamics initiated by laser-matter interaction.

  1. AN X-RAY STUDY OF THE ETHYLENE GLYCOLMONTMORILLONITE COMPLEX.

    DTIC Science & Technology

    SOILS, * MONTMORILLONITE , *GLYCOLS, *X RAY SPECTROSCOPY, X RAY SPECTRA, X RAY SPECTRA, X RAY SPECTRA, CLAY MINERALS, COMPLEX COMPOUNDS, FOURIER ANALYSIS, CRYSTAL STRUCTURE, THERMAL PROPERTIES, MATHEMATICAL MODELS.

  2. Energy-selective filtration of dental x-ray beams

    SciTech Connect

    Gelskey, D.E.; Baker, C.G.

    1981-11-01

    Samarium is known for its ability to filter simultaneously low- and high-energy x-ray photons from an x-ray beam that are not useful in producing a diagnostic radiograph. This study was undertaken to determine the optimum thickness of samarium required to minimize patient exposure and exposure time. The results indicate that use of a filter thickness of 0.16 mm. minimized patient radiation exposure and permitted the use of an exposure time sufficiently short to minimize motion unsharpness. The incorporation of a 0.16 mm. samarium filter in the x-ray beam reduced exposure by about 40 percent as compared to a 2.5 mm. aluminum filter; the exposure time must be increased approximately twice to obtain optical densities equivalent to those produced with aluminum filtration.

  3. X-ray mask and method for making

    DOEpatents

    Morales, Alfredo M.

    2004-10-26

    The present invention describes a method for fabricating an x-ray mask tool which is a contact lithographic mask which can provide an x-ray exposure dose which is adjustable from point-to-point. The tool is useful in the preparation of LIGA plating molds made from PMMA, or similar materials. In particular the tool is useful for providing an ability to apply a graded, or "stepped" x-ray exposure dose across a photosensitive substrate. By controlling the x-ray radiation dose from point-to-point, it is possible to control the development process for removing exposed portions of the substrate; adjusting it such that each of these portions develops at a more or less uniformly rate regardless of feature size or feature density distribution.

  4. Comparable Senescence Induction in Three-dimensional Human Cartilage Model by Exposure to Therapeutic Doses of X-rays or C-ions.

    PubMed

    Hamdi, Dounia Houria; Chevalier, François; Groetz, Jean-Emmanuel; Durantel, Florent; Thuret, Jean-Yves; Mann, Carl; Saintigny, Yannick

    2016-05-01

    Particle therapy using carbon ions (C-ions) has been successfully used in the treatment of tumors resistant to conventional radiation therapy. However, the potential side effects to healthy cartilage exposed to lower linear energy transfer (LET) ions in the beam track before the tumor have not been evaluated. The aim of the present study was to assess the extent of damage after C-ion irradiation in a 3-dimensional (3D) cartilage model close to human homeostasis. Primary human articular chondrocytes from a healthy donor were cultured in a collagen scaffold to construct a physioxic 3D cartilage model. A 2-dimensional (2D) culture was used as a reference. The cells were irradiated with a single dose of a monoenergetic C-ion beam with a LET of approximatively 30 keV/μm. This LET corresponds to the entrance channel of C-ions in the shallow healthy tissues before the spread-out Bragg peak (∼100 keV/μm) during hadron therapy protocols. The same dose of X-rays was used as a reference. Survival, cell death, and senescence assays were performed. As expected, in the 2D culture, C-ions were more efficient than X-rays in reducing cell survival with a relative biological effectiveness of 2.6. This correlated with stronger radiation-induced senescence (two-fold) but not with higher cell death induction. This differential effect was not reflected in the 3D culture. Both ionizing radiation types induced a comparable rate of senescence induction in the 3D model. The greater biological effectiveness of C-ions compared with low LET radiation when evaluated in treatment planning systems might be misevaluated using 2D culture experiments. Radiation-induced senescence is an important factor of potential cartilage attrition. The present data should encourage the scientific community to use relevant models and beams to improve the use of charged particles with better safety for patients. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  5. X-ray fluorescence holography.

    PubMed

    Hayashi, Kouichi; Happo, Naohisa; Hosokawa, Shinya; Hu, Wen; Matsushita, Tomohiro

    2012-03-07

    X-ray fluorescence holography (XFH) is a method of atomic resolution holography which utilizes fluorescing atoms as a wave source or a monitor of the interference field within a crystal sample. It provides three-dimensional atomic images around a specified element and has a range of up to a few nm in real space. Because of this feature, XFH is expected to be used for medium-range local structural analysis, which cannot be performed by x-ray diffraction or x-ray absorption fine structure analysis. In this article, we explain the theory of XFH including solutions to the twin-image problem, an advanced measuring system, and data processing for the reconstruction of atomic images. Then, we briefly introduce our recent applications of this technique to the analysis of local lattice distortions in mixed crystals and nanometer-size clusters appearing in the low-temperature phase of a shape-memory alloy.

  6. Ultraluminous X-Ray Sources

    NASA Astrophysics Data System (ADS)

    Kaaret, Philip; Feng, Hua; Roberts, Timothy P.

    2017-08-01

    We review observations of ultraluminous X-ray sources (ULXs). X-ray spectroscopic and timing studies of ULXs suggest a new accretion state distinct from those seen in Galactic stellar-mass black hole binaries. The detection of coherent pulsations indicates the presence of neutron-star accretors in three ULXs and therefore apparently super-Eddington luminosities. Optical and X-ray line profiles of ULXs and the properties of associated radio and optical nebulae suggest that ULXs produce powerful outflows, also indicative of super-Eddington accretion. We discuss models of super-Eddington accretion and their relation to the observed behaviors of ULXs. We review the evidence for intermediate mass black holes in ULXs. We consider the implications of ULXs for super-Eddington accretion in active galactic nuclei, heating of the early universe, and the origin of the black hole binary recently detected via gravitational waves.

  7. X-ray Timing Measurements

    NASA Technical Reports Server (NTRS)

    Strohmayer, T.

    2008-01-01

    We present new, extended X-ray timing measurements of the ultra-compact binary candidates V407 Vul and RX J0806.3+1527 (J0806), as well as a summary of the first high resolution X-ray spectra of 50806 obtained with the Chandra/LETG. The temporal baseline for both objects is approximately 12 years, and our measurements confirm the secular spin-up in their X-ray periods. The spin-up rate in 50806 is remarkably uniform at 3.55x10(exp -16)Hz/s, with a measurement precision of 0.2%. We place a limit (90% confidence) on 1 d dot nu < 4x10(exp -26)Hz/sq s. Interestingly, for V407 Vul we find the first evidence that the spin-up rate is slowing, with d dot\

  8. X-ray tensor tomography

    NASA Astrophysics Data System (ADS)

    Malecki, A.; Potdevin, G.; Biernath, T.; Eggl, E.; Willer, K.; Lasser, T.; Maisenbacher, J.; Gibmeier, J.; Wanner, A.; Pfeiffer, F.

    2014-02-01

    Here we introduce a new concept for x-ray computed tomography that yields information about the local micro-morphology and its orientation in each voxel of the reconstructed 3D tomogram. Contrary to conventional x-ray CT, which only reconstructs a single scalar value for each point in the 3D image, our approach provides a full scattering tensor with multiple independent structural parameters in each volume element. In the application example shown in this study, we highlight that our method can visualize sub-pixel fiber orientations in a carbon composite sample, hence demonstrating its value for non-destructive testing applications. Moreover, as the method is based on the use of a conventional x-ray tube, we believe that it will also have a great impact in the wider range of material science investigations and in future medical diagnostics. The authors declare no competing financial interests.

  9. Enhanced dynamic range x-ray imaging.

    PubMed

    Haidekker, Mark A; Morrison, Logan Dain-Kelley; Sharma, Ajay; Burke, Emily

    2017-03-01

    X-ray images can suffer from excess contrast. Often, image exposure is chosen to visually optimize the region of interest, but at the expense of over- and underexposed regions elsewhere in the image. When image values are interpreted quantitatively as projected absorption, both over- and underexposure leads to the loss of quantitative information. We propose to combine multiple exposures into a composite that uses only pixels from those exposures in which they are neither under- nor overexposed. The composite image is created in analogy to visible-light high dynamic range photography. We present the mathematical framework for the recovery of absorbance from such composite images and demonstrate the method with biological and non-biological samples. We also show with an aluminum step-wedge that accurate recovery of step thickness from the absorbance values is possible, thereby highlighting the quantitative nature of the presented method. Due to the higher amount of detail encoded in an enhanced dynamic range x-ray image, we expect that the number of retaken images can be reduced, and patient exposure overall reduced. We also envision that the method can improve dual energy absorptiometry and even computed tomography by reducing the number of low-exposure ("photon-starved") projections.

  10. Mice heterozygous for the ATM gene are more sensitive to both X-ray and heavy ion exposure than are wildtypes

    NASA Astrophysics Data System (ADS)

    Worgul, B. V.; Smilenov, L.; Brenner, D. J.; Vazquez, M.; Hall, E. J.

    Previous studies have shown that the eyes of ATM heterozygous mice exposed to low-LET radiation (X-rays) are significantly more susceptible to the development of cataracts than are those of wildtype mice. The findings, as well as others, run counter to the assumption underpinning current radiation safety guidelines, that individuals are all equally sensitive to the biological effects of radiation. A question, highly relevant to human space activities is whether or not, in similar fashion there may exist a genetic predisposition to high-LET radiation damage. Mice haplodeficient for the ATM gene and wildtypes were exposed to 325 mGy of 1 GeV/amu 56Fe ions at the AGS facility of Brookhaven National Laboratory. The fluence was equivalent to 1 ion per lens epithelial cell nuclear area. Controls consisted of irradiated wildtype as well as unirradiated wildtype and heterozygous mice. Prevalence analyses for stage 0.5-3.0 cataracts indicated that not only cataract onset but also progression were accelerated in the mice haplo-deficient for the ATM gene. The data show that heterozygosity for the ATM gene predisposes the eye to the cataractogenic influence of heavy ions and suggest that ATM heterozygotes in the human population may also be radiosensitive. This may have to be considered in the selection of individuals who will be exposed to both HZE particles and low-LET radiation as they may be predisposed to increased late normal tissue damage.

  11. Portable X-Ray Device

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Portable x-ray instrument developed by NASA now being produced commercially as an industrial tool may soon find further utility as a medical system. The instrument is Lixiscope - Low Intensity X-Ray Imaging Scope -- a self-contained, battery-powered fluoroscope that produces an instant image through use of a small amount of radioactive isotope. Originally developed by Goddard Space Flight Center, Lixiscope is now being produced by Lixi, Inc. which has an exclusive NASA license for one version of the device.

  12. Cosmic X-ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, D.; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1986-01-01

    The analysis of the beryllium-filtered data from Flight 17.020 was completed. The data base provided by the Wisconsin diffuse X-ray sky survey is being analyzed by correlating the B and C band emission with individual velocity components of neutral hydrogen. Work on a solid state detector to be used in high resolution spectroscopy of diffuse or extend X-ray sources is continuing. A series of 21 cm observations was completed. A paper on the effects of process parameter variation on the reflectivity of sputter-deposited tungsten-carvon multilayers was published.

  13. X-ray emission spectroscopy.

    PubMed

    Bergmann, Uwe; Glatzel, Pieter

    2009-01-01

    We describe the chemical information that can be obtained by means of hard X-ray emission spectroscopy (XES). XES is presented as a technique that is complementary to X-ray absorption spectroscopy (XAS) and that provides valuable information with respect to the electronic structure (local charge- and spin-density) as well as the ligand environment of a 3d transition metal. We address non-resonant and resonant XES and present results that were recorded on Mn model systems and the Mn(4)Ca-cluster in the oxygen evolving complex of photosystem II. A brief description of the instrumentation is given with an outlook toward future developments.

  14. X-rays from stars.

    PubMed

    Güdel, Manuel

    2002-09-15

    More than two years of observation with Chandra and XMM-Newton has provided a rich harvest of new results on the physics of stellar coronae and winds. High-resolution X-ray spectroscopy in particular has opened new windows to the structure, the dynamics and the composition of stellar atmospheres. The present paper presents selected results from the areas of hot and cool stars and star formation, summarizing new views of the thermal structure and energy release in stellar coronae, observations of magnetically active brown dwarfs, the structure of winds in hot stars, the physics in colliding-wind binary systems, and X-rays from protostars and stellar jets.

  15. Chest X-Ray (Chest Radiography)

    MedlinePlus

    ... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Chest Chest x-ray uses a very ... limitations of Chest Radiography? What is a Chest X-ray (Chest Radiography)? The chest x-ray is the ...

  16. Compact Flash X-Ray Units

    DTIC Science & Technology

    1995-07-01

    Flash x-ray units are used to diagnose pulsed power driven experiments on the Pegasus machine at Los Alamos. Several unique designs of Marx powered...employing an x-ray tube configuration which allows closely spaced x-ray emitting anodes. These units all emit a 10 ns FWHM x-ray pulse. Their Marx banks

  17. Comparative studies of X-ray images and fluorescence images of the same specimens

    NASA Astrophysics Data System (ADS)

    Majima, T.; Tomie, T.; Shimizu, H.

    2003-03-01

    A flash contact soft x-ray microscope using laser-induced plasma as a flash x-ray source is a practical instrument for observation of living organisms in water [1-4]. As previously reported we developed a tabletop flash contact soft x-ray microscope System [3]. In this System, x-ray images are given as whole projection of the specimens on the PMMA membrane. This causes us some complexity for understanding the x-ray images. It is necessary to attribute features in the x-ray images to sub-cellular structures of the specimen. For this purpose we have developed a new sample holder, where specimens are observable with a fluorescence microscope just before x-ray exposure. Fluorescence images of onion epidermal cells stained by DAPI and x-ray images of the same specimens are compared.

  18. X-ray face mask and chest shield device

    SciTech Connect

    Moti, S.

    1981-08-25

    A protective face mask is disclosed that is designed to shield an x-ray technician or machine operator primarily from random secondary or scatter x-rays deflected toward his face, head and neck by the table, walls, equipment and other reflecting elements in an x-ray room or chamber, during the period of exposure while adjacent the object or person being exposed to the x-ray beam. The face mask and chest shield device can be mounted on a patient's shoulders in reverse attitude to protect the back of a patient's head and neck from the x-ray beam while being exposed to such beam for chest or upper body portion study and examination. The face mask is relatively or substantially transparent and contains lead in combination with a plastic ionomer or comonomer, which absorbs or resists penetration, to a degree, of the random deflected secondary or scatter x-rays or the x-ray beam through the mask. The face mask is removably attachable to the chest shield for facile application of the device to and support upon the shoulders of the technician or the patient.

  19. X-rays: what the nurse needs to know.

    PubMed

    Myatt, Rebecca

    2017-08-30

    Rationale and key points X-ray imaging is a form of electromagnetic radiation that is able to pass through the human body producing an image of the internal structures. X-rays are one of the main investigations for confirming a suspected diagnosis. Developing an understanding of the underlying mechanism and the rationale for requesting an X-ray will increase nurses' understanding of the process and enable improved patient preparation through explanation and reassurance. This article provides an overview of the fundamental principles underlying the process of obtaining an X-ray. » X-ray imaging is a common diagnostic tool that nurses will encounter on a regular basis. » Several factors affect the production of a clear X-ray image, including patient movement. » Radiation safety and avoidance of unnecessary exposure are paramount. » Co-operation and communication by the multidisciplinary team are vital to ensure that X-ray imaging can be requested, performed, interpreted and acted on, and the findings communicated to the patient.

  20. BAT X-Ray Survey. I. Methodology and X-Ray Identification

    NASA Astrophysics Data System (ADS)

    Ajello, M.; Greiner, J.; Kanbach, G.; Rau, A.; Strong, A. W.; Kennea, J. A.

    2008-05-01

    We applied the maximum likelihood (ML) method, as an image reconstruction algorithm, to the BAT X-Ray Survey (BXS). This method was specifically designed to preserve the full statistical information in the data and to avoid mosaicking of many exposures with different pointing directions, thus reducing systematic errors when co-adding images. We reconstructed, in the 14-170 keV energy band, the image of a 90 × 90 deg2 sky region, centered on (R .A ., decl .) = (105°, - 25°) , which BAT surveyed with an exposure time of ~1 Ms (in 2005 November). The best sensitivity in our image is ~0.85 mcrab or 2.0 × 10-11 ergs cm-2. We detect 49 hard X-ray sources above the 4.5 σ level; of these, only 12 were previously known as hard X-ray sources (>15 keV). Swift XRT observations allowed us to firmly identify the counterparts for 15 objects, while 2 objects have Einstein IPC counterparts (Harris et al. 1990); in addition to those, we found a likely counterpart for 13 objects by correlating our sample with the ROSAT All-Sky Survey Bright Source Catalog (Voges et al. 1999). Seven objects remain unidentified. Analysis of the noise properties of our image shows that ~75% of the area is surveyed to a flux limit of ~1 mcrab. This study shows that the coupling of the ML method to the most sensitive, all-sky surveying, hard X-ray instrument, BAT, is able to probe for the first time the hard X-ray sky to the millicrab flux level. The successful application of this method to BAT demonstrates that it could also be applied with advantage to similar instruments such as INTEGRAL IBIS.

  1. X-ray backscatter imaging

    NASA Astrophysics Data System (ADS)

    Dinca, Dan-Cristian; Schubert, Jeffrey R.; Callerame, J.

    2008-04-01

    In contrast to transmission X-ray imaging systems where inspected objects must pass between source and detector, Compton backscatter imaging allows both the illuminating source as well as the X-ray detector to be on the same side of the target object, enabling the inspection to occur rapidly and in a wide variety of space-constrained situations. A Compton backscatter image is similar to a photograph of the contents of a closed container, taken through the container walls, and highlights low atomic number materials such as explosives, drugs, and alcohol, which appear as especially bright objects by virtue of their scattering characteristics. Techniques for producing X-ray images based on Compton scattering will be discussed, along with examples of how these systems are used for both novel security applications and for the detection of contraband materials at ports and borders. Differences between transmission and backscatter images will also be highlighted. In addition, tradeoffs between Compton backscatter image quality and scan speed, effective penetration, and X-ray source specifications will be discussed.

  2. Rontgen's Discovery of X Rays

    ERIC Educational Resources Information Center

    Thumm, Walter

    1975-01-01

    Relates the story of Wilhelm Conrad Rontgen and presents one view of the extent to which the discovery of the x-ray was an accident. Reconstructs the sequence of events that led to the discovery and includes photographs of the lab where he worked and replicas of apparatus used. (GS)

  3. Focused X-ray source

    DOEpatents

    Piestrup, M.A.; Boyers, D.G.; Pincus, C.I.; Maccagno, P.

    1990-08-21

    Disclosed is an intense, relatively inexpensive X-ray source (as compared to a synchrotron emitter) for technological, scientific, and spectroscopic purposes. A conical radiation pattern produced by a single foil or stack of foils is focused by optics to increase the intensity of the radiation at a distance from the conical radiator. 8 figs.

  4. Stellar X-Ray Polarimetry

    NASA Technical Reports Server (NTRS)

    Swank, J.

    2011-01-01

    Most of the stellar end-state black holes, pulsars, and white dwarfs that are X-ray sources should have polarized X-ray fluxes. The degree will depend on the relative contributions of the unresolved structures. Fluxes from accretion disks and accretion disk corona may be polarized by scattering. Beams and jets may have contributions of polarized emission in strong magnetic fields. The Gravity and Extreme Magnetism Small Explorer (GEMS) will study the effects on polarization of strong gravity of black holes and strong magnetism of neutron stars. Some part of the flux from compact stars accreting from companion stars has been reflected from the companion, its wind, or accretion streams. Polarization of this component is a potential tool for studying the structure of the gas in these binary systems. Polarization due to scattering can also be present in X-ray emission from white dwarf binaries and binary normal stars such as RS CVn stars and colliding wind sources like Eta Car. Normal late type stars may have polarized flux from coronal flares. But X-ray polarization sensitivity is not at the level needed for single early type stars.

  5. X-rays and magnetism.

    PubMed

    Fischer, Peter; Ohldag, Hendrik

    2015-09-01

    Magnetism is among the most active and attractive areas in modern solid state physics because of intriguing phenomena interesting to fundamental research and a manifold of technological applications. State-of-the-art synthesis of advanced magnetic materials, e.g. in hybrid structures paves the way to new functionalities. To characterize modern magnetic materials and the associated magnetic phenomena, polarized x-rays have emerged as unique probes due to their specific interaction with magnetic materials. A large variety of spectroscopic and microscopic techniques have been developed to quantify in an element, valence and site-sensitive way properties of ferro-, ferri-, and antiferromagnetic systems, such as spin and orbital moments, and to image nanoscale spin textures and their dynamics with sub-ns time and almost 10 nm spatial resolution. The enormous intensity of x-rays and their degree of coherence at next generation x-ray facilities will open the fsec time window to magnetic studies addressing fundamental time scales in magnetism with nanometer spatial resolution. This review will give an introduction into contemporary topics of nanoscale magnetic materials and provide an overview of analytical spectroscopy and microscopy tools based on x-ray dichroism effects. Selected examples of current research will demonstrate the potential and future directions of these techniques.

  6. Alpha proton x ray spectrometer

    NASA Technical Reports Server (NTRS)

    Rieder, Rudi; Waeke, H.; Economou, T.

    1994-01-01

    Mars Pathfinder will carry an alpha-proton x ray spectrometer (APX) for the determination of the elemental chemical composition of Martian rocks and soils. The instrument will measure the concentration of all major and some minor elements, including C, N, and O at levels above typically 1 percent.

  7. Focused X-ray source

    DOEpatents

    Piestrup, Melvin A.; Boyers, David G.; Pincus, Cary I.; Maccagno, Pierre

    1990-01-01

    An intense, relatively inexpensive X-ray source (as compared to a synchrotron emitter) for technological, scientific, and spectroscopic purposes. A conical radiation pattern produced by a single foil or stack of foils is focused by optics to increase the intensity of the radiation at a distance from the conical radiator.

  8. X-Rays from Pluto

    NASA Image and Video Library

    2016-09-14

    The first detection of Pluto in X-rays has been made using NASA's Chandra X-ray Observatory in conjunction with observations from NASA's New Horizons spacecraft. As New Horizons approached Pluto in late 2014 and then flew by the planet during the summer of 2015, Chandra obtained data during four separate observations. During each observation, Chandra detected low-energy X-rays from the small planet. The main panel in this graphic is an optical image taken from New Horizons on its approach to Pluto, while the inset shows an image of Pluto in X-rays from Chandra. There is a significant difference in scale between the optical and X-ray images. New Horizons made a close flyby of Pluto but Chandra is located near the Earth, so the level of detail visible in the two images is very different. The Chandra image is 180,000 miles across at the distance of Pluto, but the planet is only 1,500 miles across. Pluto is detected in the X-ray image as a point source, showing the sharpest level of detail available for Chandra or any other X-ray observatory. This means that details over scales that are smaller than the X-ray source cannot be seen here. Detecting X-rays from Pluto is a somewhat surprising result given that Pluto - a cold, rocky world without a magnetic field - has no natural mechanism for emitting X-rays. However, scientists knew from previous observations of comets that the interaction between the gases surrounding such planetary bodies and the solar wind - the constant streams of charged particles from the sun that speed throughout the solar system -- can create X-rays. The researchers were particularly interested in learning more about the interaction between the gases in Pluto's atmosphere and the solar wind. The New Horizon spacecraft carries an instrument designed to measure that activity up-close -- Solar Wind Around Pluto (SWAP) -- and scientists examined that data and proposed that Pluto contains a very mild, close-in bowshock, where the solar wind first

  9. X-Ray Diffractive Optics

    NASA Technical Reports Server (NTRS)

    Dennis, Brian; Li, Mary; Skinner, Gerald

    2013-01-01

    X-ray optics were fabricated with the capability of imaging solar x-ray sources with better than 0.1 arcsecond angular resolution, over an order of magnitude finer than is currently possible. Such images would provide a new window into the little-understood energy release and particle acceleration regions in solar flares. They constitute one of the most promising ways to probe these regions in the solar atmosphere with the sensitivity and angular resolution needed to better understand the physical processes involved. A circular slit structure with widths as fine as 0.85 micron etched in a silicon wafer 8 microns thick forms a phase zone plate version of a Fresnel lens capable of focusing approx. =.6 keV x-rays. The focal length of the 3-cm diameter lenses is 100 microns, and the angular resolution capability is better than 0.1 arcsecond. Such phase zone plates were fabricated in Goddard fs Detector Development Lab. (DDL) and tested at the Goddard 600-microns x-ray test facility. The test data verified that the desired angular resolution and throughput efficiency were achieved.

  10. Performance of ultralow-dose CT with iterative reconstruction in lung cancer screening: limiting radiation exposure to the equivalent of conventional chest X-ray imaging.

    PubMed

    Huber, Adrian; Landau, Julia; Ebner, Lukas; Bütikofer, Yanik; Leidolt, Lars; Brela, Barbara; May, Michelle; Heverhagen, Johannes; Christe, Andreas

    2016-10-01

    To investigate the detection rate of pulmonary nodules in ultralow-dose CT acquisitions. In this lung phantom study, 232 nodules (115 solid, 117 ground-glass) of different sizes were randomly distributed in a lung phantom in 60 different arrangements. Every arrangement was acquired once with standard radiation dose (100 kVp, 100 references mAs) and once with ultralow radiation dose (80 kVp, 6 mAs). Iterative reconstruction was used with optimized kernels: I30 for ultralow-dose, I70 for standard dose and I50 for CAD. Six radiologists examined the axial 1-mm stack for solid and ground-glass nodules. During a second and third step, three radiologists used maximum intensity projection (MIPs), finally checking with computer-assisted detection (CAD), while the others first used CAD, finally checking with the MIPs. The detection rate was 95.5 % with standard dose (DLP 126 mGy*cm) and 93.3 % with ultralow-dose (DLP: 9 mGy*cm). The additional use of either MIP reconstructions or CAD software could compensate for this difference. A combination of both MIP reconstructions and CAD software resulted in a maximum detection rate of 97.5 % with ultralow-dose. Lung cancer screening with ultralow-dose CT using the same radiation dose as a conventional chest X-ray is feasible. • 93.3 % of all lung nodules were detected with ultralow-dose CT. • A sensitivity of 97.5 % is possible with additional image post-processing. • The radiation dose is comparable to a standard radiography in two planes. • Lung cancer screening with ultralow-dose CT is feasible.

  11. Compact x-ray source and panel

    SciTech Connect

    Sampayon, Stephen E.

    2008-02-12

    A compact, self-contained x-ray source, and a compact x-ray source panel having a plurality of such x-ray sources arranged in a preferably broad-area pixelized array. Each x-ray source includes an electron source for producing an electron beam, an x-ray conversion target, and a multilayer insulator separating the electron source and the x-ray conversion target from each other. The multi-layer insulator preferably has a cylindrical configuration with a plurality of alternating insulator and conductor layers surrounding an acceleration channel leading from the electron source to the x-ray conversion target. A power source is connected to each x-ray source of the array to produce an accelerating gradient between the electron source and x-ray conversion target in any one or more of the x-ray sources independent of other x-ray sources in the array, so as to accelerate an electron beam towards the x-ray conversion target. The multilayer insulator enables relatively short separation distances between the electron source and the x-ray conversion target so that a thin panel is possible for compactness. This is due to the ability of the plurality of alternating insulator and conductor layers of the multilayer insulators to resist surface flashover when sufficiently high acceleration energies necessary for x-ray generation are supplied by the power source to the x-ray sources.

  12. Time-resolved X-ray PIV technique for diagnosing opaque biofluid flow with insufficient X-ray fluxes.

    PubMed

    Jung, Sung Yong; Park, Han Wook; Kim, Bo Heum; Lee, Sang Joon

    2013-05-01

    X-ray imaging is used to visualize the biofluid flow phenomena in a nondestructive manner. A technique currently used for quantitative visualization is X-ray particle image velocimetry (PIV). Although this technique provides a high spatial resolution (less than 10 µm), significant hemodynamic parameters are difficult to obtain under actual physiological conditions because of the limited temporal resolution of the technique, which in turn is due to the relatively long exposure time (~10 ms) involved in X-ray imaging. This study combines an image intensifier with a high-speed camera to reduce exposure time, thereby improving temporal resolution. The image intensifier amplifies light flux by emitting secondary electrons in the micro-channel plate. The increased incident light flux greatly reduces the exposure time (below 200 µs). The proposed X-ray PIV system was applied to high-speed blood flows in a tube, and the velocity field information was successfully obtained. The time-resolved X-ray PIV system can be employed to investigate blood flows at beamlines with insufficient X-ray fluxes under specific physiological conditions. This method facilitates understanding of the basic hemodynamic characteristics and pathological mechanism of cardiovascular diseases.

  13. Monochromatic X-ray imaging using a combination of doubly curved crystal and polycapillary X-ray lens.

    PubMed

    Sun, Tianxi; MacDonald, C A

    2015-01-01

    A monochromatic X-ray imaging setup based on a combination of a doubly curved crystal and a polycapillary focusing X-ray lens was designed. In this setup, the bent crystal optic was used not only to monochromatize but also to focus the divergent X-ray beam from a conventional X-ray source to form a monochromatic X-ray focal spot with a size of 426 × 467 μm2 at 17.5 keV. The beam expanding from this focal point was focused by the polycapillary optic to obtain a focal spot which was then used as the monochromatic X-ray imaging virtual source. The output focal spot size of the focusing polycapillary optic at 17.5 keV was 97 μm. Compared with the beam expansion after the focal spot of the bent crystal optic, the beam expansion after the focal spot of the focusing polycapillary optic was relatively large. This was helpful for magnifying the X-ray image of the sample. The focused beam was helpful to decrease the exposure time for imaging small samples.

  14. Projection x-ray topography system at 1-BM x-ray optics test beamline at the advanced photon source

    SciTech Connect

    Stoupin, Stanislav Liu, Zunping; Trakhtenberg, Emil; Lang, Keenan; Goetze, Kurt; Sullivan, Joseph; Macrander, Albert; Raghothamachar, Balaji; Dudley, Michael

    2016-07-27

    Projection X-ray topography of single crystals is a classic technique for the evaluation of intrinsic crystal quality of large crystals. In this technique a crystal sample and an area detector (e.g., X-ray film) collecting intensity of a chosen crystallographic reflection are translated simultaneously across an X-ray beam collimated in the diffraction scattering plane (e.g., [1, 2]). A bending magnet beamline of a third-generation synchrotron source delivering x-ray beam with a large horizontal divergence, and therefore, a large horizontal beam size at a crystal sample position offers an opportunity to obtain X-ray topographs of large crystalline samples (e.g., 6-inch wafers) in just a few exposures. Here we report projection X-ray topography system implemented recently at 1-BM beamline of the Advanced Photon Source. A selected X-ray topograph of a 6-inch wafer of 4H-SiC illustrates capabilities and limitations of the technique.

  15. [Fluorogram using digital X-ray cineradiography].

    PubMed

    Higashikawa, Masahiko; Yamamoto, Yumiko; Mineharu, Akihito

    2006-08-01

    We discussed the usefulness of fluorogram obtained using digital X-ray cineradiography (digital-cine-fluorograpy) in the diagnosis of dysphagia, comparied with that of video-fluorograpy. Digital-cine-fluorograpy produces five frames per second. A qualitative evaluation comfirmed that five frames per second was sufficient to grasp movement during swallowing in clinical setting. Digital-cine-fluorograpy imaging was also convenient for clinical practice in that the medical records can be accessed from any workstation. Although the maximum photography time (around 10 seconds) is limited and a higher exposure dose is required, we concluded that digital-cine-fluorograpy is a useful tool for the diagnosis of dysphagia.

  16. Low dose hard x-ray contact microscopy assisted by a photoelectric conversion layer

    SciTech Connect

    Gomella, Andrew; Martin, Eric W.; Lynch, Susanna K.; Wen, Han; Morgan, Nicole Y.

    2013-04-15

    Hard x-ray contact microscopy provides images of dense samples at resolutions of tens of nanometers. However, the required beam intensity can only be delivered by synchrotron sources. We report on the use of a gold photoelectric conversion layer to lower the exposure dose by a factor of 40 to 50, allowing hard x-ray contact microscopy to be performed with a compact x-ray tube. We demonstrate the method in imaging the transmission pattern of a type of hard x-ray grating that cannot be fitted into conventional x-ray microscopes due to its size and shape. Generally the method is easy to implement and can record images of samples in the hard x-ray region over a large area in a single exposure, without some of the geometric constraints associated with x-ray microscopes based on zone-plate or other magnifying optics.

  17. Low dose hard x-ray contact microscopy assisted by a photoelectric conversion layer

    PubMed Central

    Gomella, Andrew; Martin, Eric W.; Lynch, Susanna K.; Morgan, Nicole Y.; Wen, Han

    2013-01-01

    Hard x-ray contact microscopy provides images of dense samples at resolutions of tens of nanometers. However, the required beam intensity can only be delivered by synchrotron sources. We report on the use of a gold photoelectric conversion layer to lower the exposure dose by a factor of 40 to 50, allowing hard x-ray contact microscopy to be performed with a compact x-ray tube. We demonstrate the method in imaging the transmission pattern of a type of hard x-ray grating that cannot be fitted into conventional x-ray microscopes due to its size and shape. Generally the method is easy to implement and can record images of samples in the hard x-ray region over a large area in a single exposure, without some of the geometric constraints associated with x-ray microscopes based on zone-plate or other magnifying optics. PMID:23837131

  18. The IHS diagnostic X-ray equipment radiation protection program

    SciTech Connect

    Knapp, A.; Byrns, G.; Suleiman, O.

    1994-05-01

    The Indian Health Service (IHS) operates or contracts with Tribal groups to operate 50 hospitals and approximately 165 primary ambulatory care centers. These facilities contain approximately 275 medical and 800 dental diagnostic x-ray machines. IHS environmental health personnel in collaboration with the Food and Drug Administration's (FDA) Center for Devices and Radiological Health (CDRH) developed a diagnostic x-ray protection program including standard survey procedures and menu-driven calculations software. Important features of the program include the evaluation of equipment performance collection of average patient entrance skin exposure (ESE) measurements for selected procedures, and quality assurance. The ESE data, collected using the National Evaluation of X-ray Trends (NEXT) protocol, will be presented. The IHS Diagnostic X-ray Radiation Protection Program is dynamic and is adapting to changes in technology and workload.

  19. X-Ray Streak Camera.

    NASA Astrophysics Data System (ADS)

    Jaanimagi, Paul Ants

    Streak cameras are acknowledged as the only instruments capable of unambiguously diagnosing optical phenomena with a time resolution of the order of a picosecond on a single shot basis. As streak cameras become more extensively used for diagnostics in such fields as picosecond laser pulse generation, photo-chemistry, laser produced plasma studies, the instrument's capabilities are also being examined and limitations are becoming noticeable. One of the aims of this dissertation is to investigate the question of streak camera fidelity, especially with regard to linearity and dynamic range as a function of the time resolution. It is shown that the dynamic range is proportional to the product of the instrumental time resolution and the pulse width. The implications for femtosecond diagnostic capability are self-evident but a study of the sources of the limitations suggest distinct avenues for improving the systems. Since a streak camera employs an electron analog of the optical signal, clearly space charge will cause significant distortion at large current densities and consequently limit the dynamic range. Problems also result from nonlinear photocathode response, electron lens distortions, time of flight dispersion, phosphor reciprocity failure and nonlinear intensifier gain. The solution for some of these problems requires modifications to the basic tube designs. The National Research Council of Canada x-ray streak camera (based on a RCA C73435 image tube) was used as the starting point for testing electron optic designs and implementing the desired modifications. The objective of this work was to improve our x-ray diagnostic in sensitivity and in time resolution capability to < 10 ps. Ultimately this streak camera was to be used to time resolve the x -ray emission from plasmas produced by the COCO II and high pressure CO(,2) laser facilities at NRC. Features of the redesigned x-ray streak camera include: a large photocathode area (1.3 x 25 mm), a photoelectron

  20. Dosimetry of x-ray beams: The measure of the problem

    SciTech Connect

    de Castro, T.M.

    1986-08-01

    This document contains the text of an oral presentation on dosimetry of analytical x-ray equipment presented at the Denver X-Ray Conference. Included are discussions of sources of background radiation, exposure limits from occupational sources, and the relationship of these sources to the high dose source of x-rays found in analytical machines. The mathematical basis of x-ray dosimetry is reviewed in preparation for more detailed notes on personnel dosimetry and the selection of the most appropriate dosimeter for a specific application. The presentation concludes with a discussion common to previous x-ray equipment accidents. 2 refs. (TEM)

  1. Note: Application of laser produced plasma Kα x-ray probe in radiation biology

    NASA Astrophysics Data System (ADS)

    Nishikino, Masaharu; Sato, Katsutoshi; Hasegawa, Noboru; Ishino, Masahiko; Ohshima, Shinsuke; Okano, Yasuaki; Kawachi, Tetsuya; Numasaki, Hodaka; Teshima, Tetruki; Nishimura, Hiroaki

    2010-02-01

    A dedicated radiation biology x-ray generation and exposure system has been developed. 8.0 keV in energy x-ray pulses generated with a femtosecond-laser pulse was used to irradiate sample cells through a custom-made culture dish with a silicon nitride membrane. The x-ray irradiation resulted in DNA double-strand breaks in the nucleus of a culture cell that were similar to those obtained with a conventional x-ray source, thus demonstrating the feasibility of radiobiological studies utilizing a single burst of x-rays focused on single cell specimens.

  2. Note: Application of laser produced plasma K alpha x-ray probe in radiation biology.

    PubMed

    Nishikino, Masaharu; Sato, Katsutoshi; Hasegawa, Noboru; Ishino, Masahiko; Ohshima, Shinsuke; Okano, Yasuaki; Kawachi, Tetsuya; Numasaki, Hodaka; Teshima, Tetruki; Nishimura, Hiroaki

    2010-02-01

    A dedicated radiation biology x-ray generation and exposure system has been developed. 8.0 keV in energy x-ray pulses generated with a femtosecond-laser pulse was used to irradiate sample cells through a custom-made culture dish with a silicon nitride membrane. The x-ray irradiation resulted in DNA double-strand breaks in the nucleus of a culture cell that were similar to those obtained with a conventional x-ray source, thus demonstrating the feasibility of radiobiological studies utilizing a single burst of x-rays focused on single cell specimens.

  3. X-ray reprocessing in binaries

    NASA Astrophysics Data System (ADS)

    Paul, Biswajit

    2016-07-01

    We will discuss several aspects of X-ray reprocessing into X-rays or longer wavelength radiation in different kinds of binary systems. In high mass X-ray binaries, reprocessing of hard X-rays into emission lines or lower temperature black body emission is a useful tool to investigate the reprocessing media like the stellar wind, clumpy structures in the wind, accretion disk or accretion stream. In low mass X-ray binaries, reprocessing from the surface of the companion star, the accretion disk, warps and other structures in the accretion disk produce signatures in longer wavelength radiation. X-ray sources with temporal structures like the X-ray pulsars and thermonuclear burst sources are key in such studies. We will discuss results from several new investigations of X-ray reprocessing phenomena in X-ray binaries.

  4. U.S. EPA'S ACUTE REFERENCE EXPOSURE METHODOLOGY FOR ACUTE INHALATION EXPOSURES

    EPA Science Inventory

    The US EPA National Center for Environmental Assessment has developed a methodology to derive acute inhalation toxicity benchmarks, called acute reference exposures (AREs), for noncancer effects. The methodology provides guidance for the derivation of chemical-specific benchmark...

  5. Center for X-Ray Optics, 1986

    SciTech Connect

    Not Available

    1987-07-01

    The Center for X-Ray Optics has made substantial progress during the past year on the development of very high resolution x-ray technologies, the generation of coherent radiation at x-ray wavelengths, and, based on these new developments, had embarked on several scientific investigations that would not otherwise have been possible. The investigations covered in this report are topics on x-ray sources, x-ray imaging and applications, soft x-ray spectroscopy, synchrotron radiation, advanced light source and magnet structures for undulators and wigglers. (LSP)

  6. Effective X-ray beam size measurements of an X-ray tube and polycapillary X-ray lens system using a scanning X-ray fluorescence method

    NASA Astrophysics Data System (ADS)

    Gherase, Mihai R.; Vargas, Andres Felipe

    2017-03-01

    Size measurements of an X-ray beam produced by an integrated polycapillary X-ray lens (PXL) and X-ray tube system were performed by means of a scanning X-ray fluorescence (SXRF) method using three different metallic wires. The beam size was obtained by fitting the SXRF data with the analytical convolution between a Gaussian and a constant functions. For each chemical element in the wire an effective energy was calculated based on the incident X-ray spectrum and its photoelectric cross section. The proposed method can be used to measure the effective X-ray beam size in XRF microscopy studies.

  7. Ultraluminous X-ray Sources

    NASA Astrophysics Data System (ADS)

    Fabrika, S.

    2017-06-01

    The origin of Ultraluminous X-ray sources (ULXs) in external galaxies whose X-ray luminosities exceed those of the brightest black holes in our Galaxy by hundreds and thousands of times is mysterious. Here we report that all nearby persistent ULXs ever spectroscopically observed have the same optical spectra similar to that of SS 433, the only known supercritical accretor in our Galaxy. The spectra are apparently of WNL type (late nitrogen Wolf-Rayet stars) or LBV (luminous blue variables) in their hot state, which are very scarce stellar objects. We find that the spectra do not originate from WNL/LBV type donors and not in heated accretion disks, but from very hot winds from the accretion disks, which have similar physical conditions as the stellar winds from these stars. Our results suggest that bona-fide ULXs must constitute a homogeneous class of objects, which most likely have supercritical accretion disks.

  8. Microgap x-ray detector

    DOEpatents

    Wuest, Craig R.; Bionta, Richard M.; Ables, Elden

    1994-01-01

    An x-ray detector which provides for the conversion of x-ray photons into photoelectrons and subsequent amplification of these photoelectrons through the generation of electron avalanches in a thin gas-filled region subject to a high electric potential. The detector comprises a cathode (photocathode) and an anode separated by the thin, gas-filled region. The cathode may comprise a substrate, such a beryllium, coated with a layer of high atomic number material, such as gold, while the anode can be a single conducting plane of material, such as gold, or a plane of resistive material, such as chromium/silicon monoxide, or multiple areas of conductive or resistive material, mounted on a substrate composed of glass, plastic or ceramic. The charge collected from each electron avalanche by the anode is passed through processing electronics to a point of use, such as an oscilloscope.

  9. Microgap x-ray detector

    DOEpatents

    Wuest, C.R.; Bionta, R.M.; Ables, E.

    1994-05-03

    An x-ray detector is disclosed which provides for the conversion of x-ray photons into photoelectrons and subsequent amplification of these photoelectrons through the generation of electron avalanches in a thin gas-filled region subject to a high electric potential. The detector comprises a cathode (photocathode) and an anode separated by the thin, gas-filled region. The cathode may comprise a substrate, such a beryllium, coated with a layer of high atomic number material, such as gold, while the anode can be a single conducting plane of material, such as gold, or a plane of resistive material, such as chromium/silicon monoxide, or multiple areas of conductive or resistive material, mounted on a substrate composed of glass, plastic or ceramic. The charge collected from each electron avalanche by the anode is passed through processing electronics to a point of use, such as an oscilloscope. 3 figures.

  10. Tunable Coherent X-rays.

    PubMed

    Attwood, D; Halbach, K; Kim, K J

    1985-06-14

    A modern 1- to 2-billion-electron-volt synchrotron radiation facility (based on high-brightness electron beams and magnetic undulators) would generate coherent (laser-like) soft x-rays of wavelengths as short as 10 angstroms. The radiation would also be broadly tunable and subject to full polarization control. Radiation with these properties could be used for phase- and element-sensitive microprobing of biological assemblies and material interfaces as well as reserch on the production of electronic microstructures with features smaller than 1000 angstroms. These short wavelength capabilities, which extend to the K-absorption edges of carbon, nitrogen, and oxygen, are neither available nor projected for laboratory XUV lasers. Higher energy storage rings (5 to 6 billion electron volts) would generate significantly less coherent radiation and would be further compromised by additional x-ray thermal loading of optical components.

  11. Hard X-ray astrophysics

    NASA Technical Reports Server (NTRS)

    Rothschild, R. E.

    1981-01-01

    Past hard X-ray and lower energy satellite instruments are reviewed and it is shown that observation above 20 keV and up to hundreds of keV can provide much valuable information on the astrophysics of cosmic sources. To calculate possible sensitivities of future arrays, the efficiencies of a one-atmosphere inch gas counter (the HEAO-1 A-2 xenon filled HED3) and a 3 mm phoswich scintillator (the HEAO-1 A-4 Na1 LED1) were compared. Above 15 keV, the scintillator was more efficient. In a similar comparison, the sensitivity of germanium detectors did not differ much from that of the scintillators, except at high energies where the sensitivity would remain flat and not rise with loss of efficiency. Questions to be addressed concerning the physics of active galaxies and the diffuse radiation background, black holes, radio pulsars, X-ray pulsars, and galactic clusters are examined.

  12. X-Ray Crystallography Reagent

    NASA Technical Reports Server (NTRS)

    Morrison, Dennis R. (Inventor); Mosier, Benjamin (Inventor)

    2003-01-01

    Microcapsules prepared by encapsulating an aqueous solution of a protein, drug or other bioactive substance inside a semi-permeable membrane by are disclosed. The microcapsules are formed by interfacial coacervation under conditions where the shear forces are limited to 0-100 dynes per square centimeter at the interface. By placing the microcapsules in a high osmotic dewatering solution. the protein solution is gradually made saturated and then supersaturated. and the controlled nucleation and crystallization of the protein is achieved. The crystal-filled microcapsules prepared by this method can be conveniently harvested and stored while keeping the encapsulated crystals in essentially pristine condition due to the rugged. protective membrane. Because the membrane components themselves are x-ray transparent, large crystal-containing microcapsules can be individually selected, mounted in x-ray capillary tubes and subjected to high energy x-ray diffraction studies to determine the 3-D smucture of the protein molecules. Certain embodiments of the microcapsules of the invention have composite polymeric outer membranes which are somewhat elastic, water insoluble, permeable only to water, salts, and low molecular weight molecules and are structurally stable in fluid shear forces typically encountered in the human vascular system.

  13. X-Ray-powered Macronovae

    NASA Astrophysics Data System (ADS)

    Kisaka, Shota; Ioka, Kunihito; Nakar, Ehud

    2016-02-01

    A macronova (or kilonova) was observed as an infrared excess several days after the short gamma-ray burst GRB 130603B. Although the r-process radioactivity is widely discussed as an energy source, it requires a huge mass of ejecta from a neutron star (NS) binary merger. We propose a new model in which the X-ray excess gives rise to the simultaneously observed infrared excess via thermal re-emission, and explore what constraints this would place on the mass and velocity of the ejecta. This X-ray-powered model explains both the X-ray and infrared excesses with a single energy source such as the central engine like a black hole, and allows for a broader parameter region than the previous models, in particular a smaller ejecta mass ˜ {10}-3{--}{10}-2{M}⊙ and higher iron abundance mixed as suggested by general relativistic simulations for typical NS-NS mergers. We also discuss the other macronova candidates in GRB 060614 and GRB 080503, and the implications for the search of electromagnetic counterparts to gravitational waves.

  14. X-ray imaging and x-ray source development at Lawrence Livermore National Laboratory

    SciTech Connect

    Trebes, J.; Balhorn, R.; Anderson, E.

    1993-12-01

    The Laser Program at Lawrence Livermore National Laboratory has a continuing effort to develop both x-ray sources and x-ray sources and x-ray microscopy. This effort includes the ongoing development of: (1) a wide range of x-ray lasers at the Nova Laser Facility, (2) a zone plate lens--multilayer mirror based x-ray microscope (3) three dimensional, high resolution x-ray microscopy (4) short wavelength, normal incidence multilayer x-ray mirrors, (5) compact, high average power lasers for producing x-ray lasers and laser plasma x-ray sources. We have constructed and operated an x-ray laser based transmission x-ray microscope. The advantage offered by the x-ray laser source is the extreme high brightness allows high resolution images to be made on a timescale faster than that for x-ray damage effects to appear. The microscope, consists of: the x-ray laser, a multilayer coated, near normal incidence spherical mirror used as a condenser, a silicon nitride specimen holder, an x-ray zone plate used as an objective lens, and a microchannel plate x-ray detector. The x-ray laser used is the Ni-like Ta x-ray laser operating with a wavelength of 4.48 nm, a pulselength of 200 spec, a divergence of 10 mrad, and an output energy of 10 microjoules.

  15. Automatic Identification of Solar X-Ray Bright Points in Hinode X-Ray Data

    NASA Technical Reports Server (NTRS)

    Adams, M. L.; Tennant, Allyn F.; Cirtain, J. W.

    2010-01-01

    We have automated a method that is used to find point sources in Chandra X-ray telescope data, to identify solar bright points in Hinode X-ray data. This tool, called lextrct, first identifies candidate sources that are brighter than the surrounding background. The algorithm also allows selected pixels to be excluded from the source-finding, thus allowing saturated pixels (from flares and/or active regions) to be ignored. We then use lextrct to fit the sources to two-dimensional, elliptical Gaussians. The size and orientation give an approximation of the shape of the bright points. We are in the process of analyzing observations through the Al_poly filter with a four-second exposure time, to obtain a catalogue of bright points, which will include their sizes, lifetimes, intensities, and position on the solar disk

  16. Order of magnitude reduction of fluoroscopic x-ray dose

    NASA Astrophysics Data System (ADS)

    Bal, Abhinav; Robert, Normand; Machan, Lindsay; Deutsch, Meir; Kisselgoff, David; Babyn, Paul; Rowlands, John A.

    2012-03-01

    The role of fluoroscopic imaging is critical for diagnostic and image guided therapy. However, fluoroscopic imaging can require significant radiation leading to increased cancer risk and non-stochastic effects such as radiation burns. Our purpose is to reduce the exposure and dose to the patient by an order of magnitude in these procedures by use of the region of interest method. Method and Materials: Region of interest fluoroscopy (ROIF) uses a partial attenuator. The central region of the image has full exposure while the image periphery, there to provide context only, has a reduced exposure rate. ROIF using a static partial attenuator has been shown in our previous studies to reduce the dose area product (DAP) to the patient by at least 2.5 times. Significantly greater reductions in DAP would require improvements in flat panel detectors performance at low x-ray exposures or a different x-ray attenuation strategy. Thus we have investigated a second, dynamic, approach. We have constructed an x-ray shutter system allowing a normal x-ray exposure in the region of interest while reducing the number of x-ray exposures in the periphery through the rapid introduction, positioning and removal of an x-ray attenuating shutter to block radiation only for selected frames. This dynamic approach eliminates the DQE(0) loss associated with the use of static partial attenuator applied to every frame thus permitting a greater reduction in DAP. Results: We have compared the two methods by modeling and determined their fundamental limits.

  17. [Detection of drug transport using X-ray techniques].

    PubMed

    Vogel, Hermann; Haller, Dirk; Laitenberger, Christina; Heinemann, Axel; Püschel, Klaus

    2006-01-01

    The purpose of the paper was to show X-ray techniques used to discover drugs transported inside the body (body packers), on the body surface, in the garments or luggage, in goods and vehicles. The analysis was based on the X-ray findings of 141 body packers caught in Hamburg between 1989 and 2004 as well as individual cases from personal collections. The use of X-rays for border and security checks is described, different technical concepts are demonstrated and examples are given, e. g. transmission (fluoroscopic) and backscatter imaging of humans, luggage, goods, and vehicles as well as X-ray spectroscopy. The results showed that body packers produce characteristic findings in native X-ray photographs, which are even more pronounced in CT scans and after application of contrast media. Backscatter imaging allows the investigation of the body surface and the clothing. Transmission and backscatter imaging is suitable for checking humans, goods, passenger cars, trucks and containers. With the help of X-ray spectroscopy suspicious substances can be identified without opening the packaging material. According to present findings, the radiation dose applied seems low compared with exposure to environmental radiation and cosmic radiation during flights. The pictures obtained with the backscatter technique show the person checked in the nude, which raises the question of privacy versus the right of the state to carry out inspections and controls.

  18. Rapid combinatorial screening by synchrotron X-ray imaging

    NASA Astrophysics Data System (ADS)

    Eba, Hiromi; Sakurai, Kenji

    2006-01-01

    An X-ray imaging system, which does not require any scans of the sample or an X-ray beam and which, therefore, dramatically reduces the amount of time required, was employed to evaluate combinatorial libraries efficiently. Two-dimensional X-ray fluorescence (XRF) images of an 8 mm × 8 mm area were observed for combinatorial substrates of manganese-cobalt spinel MnCo 2O 4 and lithium ferrite LiFeO 2 via an exposure time of 1-3 s using synchrotron X-rays. Thus, XRF signals from a whole substrate could be observed at once in a short space of time. In order to observe the chemical environment simultaneously for all materials arranged on the substrate, the fluorescent X-ray absorption fine structure (XAFS) was measured by repeating the imaging during the monochromator scans across the absorption edge for metals. This is extremely efficient because XAFS spectra for all materials placed on the common substrate are obtained from only a single energy scan. One can determine the valence numbers, as well as other aspects of the chemical environment of the metal included in each material, from the differences in spectral features and the energy shifts. Hence, combinatorial libraries can be screened very rapidly, and therefore efficiently, using the X-ray imaging system.

  19. Flash imaging of fine structures of cellular organelles by contact x-ray microscopy with a high intensity laser plasma x-ray source

    NASA Astrophysics Data System (ADS)

    Kado, Masataka; Ishino, Masahiko; Kishimoto, Maki; Tamotsu, Satoshi; Yasuda, Keiko; Kinjo, Yasuhito; Shinohara, Kunio

    2011-09-01

    X-ray flash imaging by contact microscopy with a highly intense laser-plasma x-ray source was achieved for the observation of wet biological cells. The exposure time to obtain a single x-ray image was about 600 ps as determined by the pulse duration of the driving laser pulse. The x-ray flash imaging makes it possible to capture an x-ray image of living biological cells without any artificial treatment such as staining, fixation, freezing, and so on. The biological cells were cultivated directly on the surface of the silicon nitride membranes, which are used for the x-ray microscope. Before exposing the cells to x-rays they were observed by a conventional fluorescent microscope as reference, since the fluorescent microscopes can visualize specific organelles stained with fluorescent dye. Comparing the x-ray images with the fluorescent images of the exact same cells, each cellular organelle observed in the x-ray images was identified one by one and actin filaments and mitochondria were clearly identified in the x-ray images.

  20. Hard x-ray phase contrastmicroscopy - techniques and applications

    NASA Astrophysics Data System (ADS)

    Holzner, Christian

    In 1918, Einstein provided the first description of the nature of the refractive index for X-rays, showing that phase contrast effects are significant. A century later, most x-ray microscopy and nearly all medical imaging remains based on absorption contrast, even though phase contrast offers orders of magnitude improvements in contrast and reduced radiation exposure at multi-keV x-ray energies. The work presented is concerned with developing practical and quantitative methods of phase contrast for x-ray microscopy. A theoretical framework for imaging in phase contrast is put forward; this is used to obtain quantitative images in a scanning microscope using a segmented detector, and to correct for artifacts in a commercial phase contrast x-ray nano-tomography system. The principle of reciprocity between scanning and full-field microscopes is then used to arrive at a novel solution: Zernike contrast in a scanning microscope. These approaches are compared on a theoretical and experimental basis in direct connection with applications using multi-keV x-ray microscopes at the Advanced Photon Source at Argonne National Laboratory. Phase contrast provides the best means to image mass and ultrastructure of light elements that mainly constitute biological matter, while stimulated x-ray fluorescence provides high sensitivity for studies of the distribution of heavier trace elements, such as metals. These approaches are combined in a complementary way to yield quantitative maps of elemental concentration from 2D images, with elements placed in their ultrastructural context. The combination of x-ray fluorescence and phase contrast poses an ideal match for routine, high resolution tomographic imaging of biological samples in the future. The presented techniques and demonstration experiments will help pave the way for this development.

  1. Producing X-rays at the APS

    ScienceCinema

    None

    2016-07-12

    An introduction and overview of the Advanced Photon Source at Argonne National Laboratory, the technology that produces the brightest X-ray beams in the Western Hemisphere, and the research carried out by scientists using those X-rays.

  2. Tuberculosis, advanced - chest x-rays (image)

    MedlinePlus

    ... tissue, and can cause tissue death. These chest x-rays show advanced pulmonary tuberculosis. There are multiple light ... location of cavities within these light areas. The x-ray on the left clearly shows that the opacities ...

  3. Aspergillosis - chest x-ray (image)

    MedlinePlus

    ... usually occurs in immunocompromised individuals. Here, a chest x-ray shows that the fungus has invaded the lung ... are usually seen as black areas on an x-ray. The cloudiness on the left side of this ...

  4. Advances in transmission x-ray optics

    SciTech Connect

    Ceglio, N.M.

    1983-01-01

    Recent developments in x-ray optics are reviewed. Specific advances in coded aperture imaging, zone plate lens fabrication, time and space resolved spectroscopy, and CCD x-ray detection are discussed.

  5. Phase-sensitive X-ray imager

    DOEpatents

    Baker, Kevin Louis

    2013-01-08

    X-ray phase sensitive wave-front sensor techniques are detailed that are capable of measuring the entire two-dimensional x-ray electric field, both the amplitude and phase, with a single measurement. These Hartmann sensing and 2-D Shear interferometry wave-front sensors do not require a temporally coherent source and are therefore compatible with x-ray tubes and also with laser-produced or x-pinch x-ray sources.

  6. Advanced x-ray imaging spectrometer

    NASA Technical Reports Server (NTRS)

    Callas, John L. (Inventor); Soli, George A. (Inventor)

    1998-01-01

    An x-ray spectrometer that also provides images of an x-ray source. Coded aperture imaging techniques are used to provide high resolution images. Imaging position-sensitive x-ray sensors with good energy resolution are utilized to provide excellent spectroscopic performance. The system produces high resolution spectral images of the x-ray source which can be viewed in any one of a number of specific energy bands.

  7. Miniaturized, High-Speed, Modulated X-Ray Source

    NASA Technical Reports Server (NTRS)

    Gendreau, Keith; Arzoumanian, Zaven; Kenyon, Steve; Spartana, Nick

    2013-01-01

    (TradeMark) multiplier. This system yields an extremely robust photon-driven electron source that can tolerate long, weeks or more, exposure to air with negligible degradation. The package is also small. When combined with the electron target, necessary vacuum fittings, and supporting components (but not including LED electronics or high-voltage sources), the entire modulated x-ray source weighs as little as 158 grams.

  8. Interlaboratory variation in scoring dicentric chromosomes in a case of partial-body x-ray exposure: implications for biodosimetry networking and cytogenetic "triage mode" scoring.

    PubMed

    Ainsbury, E A; Livingston, G K; Abbott, M G; Moquet, J E; Hone, P A; Jenkins, M S; Christensen, D M; Lloyd, D C; Rothkamm, K

    2009-12-01

    The international radiation biodosimetry community has recently been engaged in activities focused on establishing cooperative networks for biodosimetric triage for radiation emergency scenarios involving mass casualties. To this end, there have been several recent publications in the literature regarding the potential for shared scoring in such an accident or incident. We present details from a medical irradiation case where two independently validated laboratories found very different yields of dicentric chromosome aberrations. The potential reasons for this disparity are discussed, and the actual reason is identified as being the partial-body nature of the radiation exposure combined with differing criteria for metaphase selection. In the context of the recent networking activity, this report is intended to highlight the fact that shared scoring may produce inconsistencies and that further validation of the scoring protocols and experimental techniques may be required before the networks are prepared to deal satisfactorily with a radiological or nuclear emergency. Also, the findings presented here clearly demonstrate the limitations of the dicentric assay for estimating radiation doses after partial-body exposures and bring into question the usefulness of rapid "triage mode" scoring in such exposure scenarios.

  9. X-ray optics: Diamond brilliance

    NASA Astrophysics Data System (ADS)

    Durbin, Stephen M.; Colella, Roberto

    2010-03-01

    Most materials either absorb or transmit X-rays. This is useful for imaging but makes it notoriously difficult to build mirrors for reflective X-ray optics. A demonstration of the high X-ray reflectivity of diamond could provide a timely solution to make the most of the next generation of free-electron lasers.

  10. Student X-Ray Fluorescence Experiments

    ERIC Educational Resources Information Center

    Fetzer, Homer D.; And Others

    1975-01-01

    Describes the experimental arrangement for x-ray analysis of samples which involves the following: the radioisotopic x-ray disk source; a student-built fluorescence chamber; the energy dispersive x-ray detector, linear amplifier and bias supply; and a multichannel pulse height analyzer. (GS)

  11. Electron beam parallel X-ray generator

    NASA Technical Reports Server (NTRS)

    Payne, P.

    1967-01-01

    Broad X ray source produces a highly collimated beam of low energy X rays - a beam with 2 to 5 arc minutes of divergence at energies between 1 and 6 keV in less than 5 feet. The X ray beam is generated by electron bombardment of a target from a large area electron gun.

  12. Cryotomography x-ray microscopy state

    SciTech Connect

    Le Gros, Mark; Larabell, Carolyn A.

    2010-10-26

    An x-ray microscope stage enables alignment of a sample about a rotation axis to enable three dimensional tomographic imaging of the sample using an x-ray microscope. A heat exchanger assembly provides cooled gas to a sample during x-ray microscopic imaging.

  13. X-Ray Exam: Neck (For Parents)

    MedlinePlus

    ... Habits for TV, Video Games, and the Internet X-Ray Exam: Neck KidsHealth > For Parents > X-Ray Exam: Neck Print A A A What's in ... español Radiografía: cuello What It Is A neck X-ray is a safe and painless test that uses ...

  14. Why Do I Need X-Rays?

    MedlinePlus

    ... to your desktop! more... Why Do I Need X-Rays? Article Chapters Why Do I Need X-Rays? print full article print this chapter email this article Radiographic, or X-ray, examinations provide your dentist with an important tool ...

  15. X-Ray Exam: Femur (Upper Leg)

    MedlinePlus

    ... Habits for TV, Video Games, and the Internet X-Ray Exam: Femur (Upper Leg) KidsHealth > For Parents > X-Ray Exam: Femur (Upper Leg) Print A A A ... You Have Questions What It Is A femur X-ray is a safe and painless test that uses ...

  16. X-Ray Exam: Scoliosis (For Parents)

    MedlinePlus

    ... Habits for TV, Video Games, and the Internet X-Ray Exam: Scoliosis KidsHealth > For Parents > X-Ray Exam: Scoliosis Print A A A What's in ... You Have Questions What It Is A scoliosis X-ray is a relatively safe and painless test that ...

  17. X-Ray Exam: Cervical Spine

    MedlinePlus

    ... to 2-Year-Old X-Ray Exam: Cervical Spine KidsHealth > For Parents > X-Ray Exam: Cervical Spine Print A A A What's in this article? ... Radiografía: columna cervical What It Is A cervical spine X-ray is a safe and painless test ...

  18. Supernova SN 2014C X-ray

    NASA Image and Video Library

    2017-01-24

    This image from NASA's Chandra X-ray Observatory shows spiral galaxy NGC 7331, center, in a three-color X-ray image. Red, green and blue colors are used for low, medium and high-energy X-rays, respectively. An unusual supernova called SN 2014C has been spotted in this galaxy. http://photojournal.jpl.nasa.gov/catalog/PIA21089

  19. Student X-Ray Fluorescence Experiments

    ERIC Educational Resources Information Center

    Fetzer, Homer D.; And Others

    1975-01-01

    Describes the experimental arrangement for x-ray analysis of samples which involves the following: the radioisotopic x-ray disk source; a student-built fluorescence chamber; the energy dispersive x-ray detector, linear amplifier and bias supply; and a multichannel pulse height analyzer. (GS)

  20. X-Ray Exam: Cervical Spine

    MedlinePlus

    ... to 2-Year-Old X-Ray Exam: Cervical Spine KidsHealth > For Parents > X-Ray Exam: Cervical Spine A A A What's in this article? What ... Radiografía: columna cervical What It Is A cervical spine X-ray is a safe and painless test ...

  1. Center for X-ray Optics, 1988

    SciTech Connect

    Not Available

    1989-04-01

    This report briefly reviews the following topics: soft-x-ray imaging; reflective optics for hard x-rays; coherent XUV sources; spectroscopy with x-rays; detectors for coronary artery imaging; synchrotron-radiation optics; and support for the advanced light source.

  2. Effect of x-rays on chromosome 21 nondisjunction

    SciTech Connect

    Strigini, P.; Pierluigi, M.; Forni, G.L.; Sansone, R.; Carobbi, S.; Grasso, M.; Dagna Bricarelli, F. )

    1990-01-01

    In a series of 156 females and 149 males with a Down syndrome (DS) child, a case-control study was performed to evaluate the effect of abdominal-pelvic exposure to diagnostic x-rays prior to conception on nondisjunction (ND). Cytogenetic analysis using QFQ banding allowed unequivocal identification of ND parents as cases. Partners of ND parents were treated as control group. Odds ratio for the association of x-rays exposure and ND occurrence (stratified for sex and age) was 1.85 (borderline to significance: with a 95% confidence interval 1-3.44). Such an association appeared highly significant in older fathers and borderline to significant in younger mothers, when age groups were analyzed separately. By comparing mean parental ages at birth of the propositus, the prevalence of exposure to x-rays appeared moderately associated with aging in control parents of both sexes. Furthermore, the mean age of unexposed ND parents of paternally derived SD cases was the same as the referent population's, suggesting that age is not a risk factor for ND in the male, except for being associated with increasing exposure risk. Conversely, risk attributable to x-rays exposure in the female appears to be progressively diluted with increasing age, by strongly age-dependent high risk, presumably due to biologic factors that are not affected by environmental exposure.

  3. NuSTAR Hard X-Ray Survey of the Galactic Center Region. II. X-Ray Point Sources

    NASA Astrophysics Data System (ADS)

    Hong, JaeSub; Mori, Kaya; Hailey, Charles J.; Nynka, Melania; Zhang, Shuo; Gotthelf, Eric; Fornasini, Francesca M.; Krivonos, Roman; Bauer, Franz; Perez, Kerstin; Tomsick, John A.; Bodaghee, Arash; Chiu, Jeng-Lun; Clavel, Maïca; Stern, Daniel; Grindlay, Jonathan E.; Alexander, David M.; Aramaki, Tsuguo; Baganoff, Frederick K.; Barret, Didier; Barrière, Nicolas; Boggs, Steven E.; Canipe, Alicia M.; Christensen, Finn E.; Craig, William W.; Desai, Meera A.; Forster, Karl; Giommi, Paolo; Grefenstette, Brian W.; Harrison, Fiona A.; Hong, Dooran; Hornstrup, Allan; Kitaguchi, Takao; Koglin, Jason E.; Madsen, Kristen K.; Mao, Peter H.; Miyasaka, Hiromasa; Perri, Matteo; Pivovaroff, Michael J.; Puccetti, Simonetta; Rana, Vikram; Westergaard, Niels J.; Zhang, William W.; Zoglauer, Andreas

    2016-07-01

    We present the first survey results of hard X-ray point sources in the Galactic Center (GC) region by NuSTAR. We have discovered 70 hard (3-79 keV) X-ray point sources in a 0.6 deg{}2 region around Sgr A* with a total exposure of 1.7 Ms, and 7 sources in the Sgr B2 field with 300 ks. We identify clear Chandra counterparts for 58 NuSTAR sources and assign candidate counterparts for the remaining 19. The NuSTAR survey reaches X-ray luminosities of ˜4× and ˜8 × 10{}32 erg s{}-1 at the GC (8 kpc) in the 3-10 and 10-40 keV bands, respectively. The source list includes three persistent luminous X-ray binaries (XBs) and the likely run-away pulsar called the Cannonball. New source-detection significance maps reveal a cluster of hard (>10 keV) X-ray sources near the Sgr A diffuse complex with no clear soft X-ray counterparts. The severe extinction observed in the Chandra spectra indicates that all the NuSTAR sources are in the central bulge or are of extragalactic origin. Spectral analysis of relatively bright NuSTAR sources suggests that magnetic cataclysmic variables constitute a large fraction (>40%-60%). Both spectral analysis and logN-logS distributions of the NuSTAR sources indicate that the X-ray spectra of the NuSTAR sources should have kT > 20 keV on average for a single temperature thermal plasma model or an average photon index of Γ = 1.5-2 for a power-law model. These findings suggest that the GC X-ray source population may contain a larger fraction of XBs with high plasma temperatures than the field population.

  4. NuSTAR Hard X-Ray Survey of the Galactic Center Region. II. X-Ray Point Sources

    NASA Technical Reports Server (NTRS)

    Hong, Jaesub; Mori, Kaya; Hailey, Charles J.; Nynka, Melania; Zhang, Shou; Gotthelf, Eric; Fornasini, Francesca M.; Krivonos, Roman; Bauer, Franz; Perez, Kerstin; hide

    2016-01-01

    We present the first survey results of hard X-ray point sources in the Galactic Center (GC) region by NuSTAR. We have discovered 70 hard (3-79 keV) X-ray point sources in a 0.6 deg(sup 2) region around Sgr?A* with a total exposure of 1.7 Ms, and 7 sources in the Sgr B2 field with 300 ks. We identify clear Chandra counterparts for 58 NuSTAR sources and assign candidate counterparts for the remaining 19. The NuSTAR survey reaches X-ray luminosities of approx. 4× and approx. 8 ×10(exp 32) erg/s at the GC (8 kpc) in the 3-10 and 10-40 keV bands, respectively. The source list includes three persistent luminous X-ray binaries (XBs) and the likely run-away pulsar called the Cannonball. New source-detection significance maps reveal a cluster of hard (>10 keV) X-ray sources near the Sgr A diffuse complex with no clear soft X-ray counterparts. The severe extinction observed in the Chandra spectra indicates that all the NuSTAR sources are in the central bulge or are of extragalactic origin. Spectral analysis of relatively bright NuSTAR sources suggests that magnetic cataclysmic variables constitute a large fraction (>40%-60%). Both spectral analysis and logN-logS distributions of the NuSTAR sources indicate that the X-ray spectra of the NuSTAR sources should have kT > 20 keV on average for a single temperature thermal plasma model or an average photon index of Lambda = 1.5-2 for a power-law model. These findings suggest that the GC X-ray source population may contain a larger fraction of XBs with high plasma temperatures than the field population.

  5. X-RAY EMISSION FROM MAGNETIC MASSIVE STARS

    SciTech Connect

    Nazé, Yaël; Petit, Véronique; Rinbrand, Melanie; Owocki, Stan; Cohen, David; Ud-Doula, Asif; Wade, Gregg A.

    2014-11-01

    Magnetically confined winds of early-type stars are expected to be sources of bright and hard X-rays. To clarify the systematics of the observed X-ray properties, we have analyzed a large series of Chandra and XMM-Newton observations, corresponding to all available exposures of known massive magnetic stars (over 100 exposures covering ∼60% of stars compiled in the catalog of Petit et al.). We show that the X-ray luminosity is strongly correlated with the stellar wind mass-loss rate, with a power-law form that is slightly steeper than linear for the majority of the less luminous, lower- M-dot B stars and flattens for the more luminous, higher- M-dot O stars. As the winds are radiatively driven, these scalings can be equivalently written as relations with the bolometric luminosity. The observed X-ray luminosities, and their trend with mass-loss rates, are well reproduced by new MHD models, although a few overluminous stars (mostly rapidly rotating objects) exist. No relation is found between other X-ray properties (plasma temperature, absorption) and stellar or magnetic parameters, contrary to expectations (e.g., higher temperature for stronger mass-loss rate). This suggests that the main driver for the plasma properties is different from the main determinant of the X-ray luminosity. Finally, variations of the X-ray hardnesses and luminosities, in phase with the stellar rotation period, are detected for some objects and they suggest that some temperature stratification exists in massive stars' magnetospheres.

  6. X-ray radiation effects in multilayer epitaxial graphene

    SciTech Connect

    Hicks, Jeremy; Tinkey, Holly; Hankinson, John; Heer, Walt A. de; Conrad, Edward H.; Arora, Rajan; Kenyon, Eleazar; Chakraborty, Partha S.; Cressler, John D.; Berger, Claire

    2011-12-05

    We characterize multilayer graphene grown on C-face SiC before and after exposure to a total ionizing dose of 12 Mrad(SiO{sub 2}) using a 10 keV x-ray source. While we observe the partial peeling of the top graphene layers and the appearance of a modest Raman D-peak, we find that the electrical characteristics (mobility, sheet resistivity, free carrier concentration) of the material are mostly unaffected by radiation exposure. Combined with x-ray photoelectron spectroscopy data showing numerous carbon-oxygen bonds after irradiation, we conclude that the primary damage mechanism is through surface etching from reactive oxygen species created by the x-rays.

  7. Review of quality of x-rays for templating for total hip arthroplasty.

    PubMed

    Khan, Faiz; Ahmad, Tayyab; Condon, Finbarr; Lenehan, Brian

    2015-03-01

    Digital templating of x-rays for total hip arthroplasty is used routinely for pre-operative planning. This is to assure that appropriately sized implants are selected to replicate patient's hip biomechanics. Multiple studies have shown that templating does not always correspond to the final implants used. The aim of this study was to assess the suitability of the x-rays taken pre-operatively for templating for total hip arthroplasty. We undertook a review of a series of pre-operative templating pelvis x-rays in 100 consecutive patients undergoing total hip arthroplasty. These x-rays were compared against set criteria to determine their suitability for use for templating. We determined that six x-rays met the criteria whereas ninety four x-rays did not meet the criteria for suitable x-rays. Twenty patients had repeat x-rays. The reasons for unsuitability were inadequate opposite femur (66%), absence or incomplete template (54%), inadequate femur length (47%), external rotation (39%), absence of opposite hip (4%). The twenty repeated x-rays were also reviewed for the same parameters and two (10%) satisfied the established criteria. It is imperative that x-rays for templating for total hip arthroplasty are done to a strict standard to obtain an x-ray that is appropriate for templating and there is minimal exposure of the patient to irradiation.

  8. Advanced High Brilliance X-Ray Source

    NASA Technical Reports Server (NTRS)

    Gibson, Walter M.

    1998-01-01

    The possibility to dramatically increase the efficiency of laboratory based protein structure measurements through the use of polycapillary X-ray optics was investigated. This project initiated April 1, 1993 and concluded December 31, 1996 (including a no cost extension from June 31, 1996). This is a final report of the project. The basis for the project is the ability to collect X-rays from divergent electron bombardment laboratory X-ray sources and redirect them into quasiparallel or convergent (focused) beams. For example, a 0.1 radian (approx. 6 deg) portion of a divergent beam collected by a polycapillary collimator and transformed into a quasiparallel beam of 3 millradian (0.2 deg) could give a gain of 6(exp 2)/0.2(exp 2) x T for the intensity of a diffracted beam from a crystal with a 0.2 deg diffraction width. T is the transmission efficiency of the polycapillary diffraction optic, and for T=0.5, the gain would be 36/0.04 x O.5=45. In practice, the effective collection angle will depend on the source spot size, the input focal length of the optic (usually limited by the source spot-to-window distance on the x-ray tube) and the size of the crystal relative to the output diameter of the optic. The transmission efficiency, T, depends on the characteristics (fractional open area, surface roughness, shape and channel diameter) of the polycapillary optic and is typically in the range 0.2-0.4. These effects could substantially reduce the expected efficiency gain. During the course of this study, the possibility to use a weakly focused beam (0.5 deg convergence) was suggested which could give an additional 10-20 X efficiency gain for small samples . Weakly focused beams from double focusing mirrors are frequently used for macromolecular crystallography studies. Furthermore the crystals are typically oscillated by as much as 2 deg during each X-ray exposure in order to increase the reciprocal space (number of crystal planes) sampled and use of a slightly convergent

  9. Mobile X-Ray Unit.

    DTIC Science & Technology

    1996-10-28

    anode 8 surrounded by a coaxial annulus of stainless steel mesh which 9 serves as the cathode, control electronics, and a plurality of 10 spark gap...34Siemens-tube" configuration. More 7 particularly, the X-ray tube 16 has a conical copper/tungsten 8 anode 28, and a stainless steel mesh punched to...160 and 162 each having a typical diameter of 14 2.75 inches. The conflat flanges 160 and 162 are mated to a 15 stainless steel tube 164 having a

  10. Modeling the X-Ray Process, and X-Ray Flaw Size Parameter for POD Studies

    NASA Technical Reports Server (NTRS)

    Khoshti, Ajay

    2014-01-01

    Nondestructive evaluation (NDE) method reliability can be determined by a statistical flaw detection study called probability of detection (POD) study. In many instances the NDE flaw detectability is given as a flaw size such as crack length. The flaw is either a crack or behaving like a crack in terms of affecting the structural integrity of the material. An alternate approach is to use a more complex flaw size parameter. The X-ray flaw size parameter, given here, takes into account many setup and geometric factors. The flaw size parameter relates to X-ray image contrast and is intended to have a monotonic correlation with the POD. Some factors such as set-up parameters including X-ray energy, exposure, detector sensitivity, and material type that are not accounted for in the flaw size parameter may be accounted for in the technique calibration and controlled to meet certain quality requirements. The proposed flaw size parameter and the computer application described here give an alternate approach to conduct the POD studies. Results of the POD study can be applied to reliably detect small flaws through better assessment of effect of interaction between various geometric parameters on the flaw detectability. Moreover, a contrast simulation algorithm for a simple part-source-detector geometry using calibration data is also provided for the POD estimation.

  11. Modeling the X-ray Process, and X-ray Flaw Size Parameter for POD Studies

    NASA Technical Reports Server (NTRS)

    Koshti, Ajay M.

    2014-01-01

    Nondestructive evaluation (NDE) method reliability can be determined by a statistical flaw detection study called probability of detection (POD) study. In many instances, the NDE flaw detectability is given as a flaw size such as crack length. The flaw is either a crack or behaving like a crack in terms of affecting the structural integrity of the material. An alternate approach is to use a more complex flaw size parameter. The X-ray flaw size parameter, given here, takes into account many setup and geometric factors. The flaw size parameter relates to X-ray image contrast and is intended to have a monotonic correlation with the POD. Some factors such as set-up parameters, including X-ray energy, exposure, detector sensitivity, and material type that are not accounted for in the flaw size parameter may be accounted for in the technique calibration and controlled to meet certain quality requirements. The proposed flaw size parameter and the computer application described here give an alternate approach to conduct the POD studies. Results of the POD study can be applied to reliably detect small flaws through better assessment of effect of interaction between various geometric parameters on the flaw detectability. Moreover, a contrast simulation algorithm for a simple part-source-detector geometry using calibration data is also provided for the POD estimation.

  12. Instrumentation for Microfabrication with Deep X-ray Lithography

    NASA Astrophysics Data System (ADS)

    Pantenburg, F. J.

    2007-01-01

    Deep X-ray lithography for microfabrication is performed at least at ten synchrotron radiation centers worldwide. The characteristic energies of these sources range from 1.4 keV up to 8 keV, covering mask making capabilities, deep X-ray lithography up to ultra deep x-ray lithography of several millimeters resist thickness. Limitations in deep X-ray lithography arise from hard X-rays in the SR-spectrum leading to adhesion losses of resist lines after the developing process, as well as heat load due to very high fluxes leading to thermal expansion of mask and resist during exposure and therefore to microstructure distortion. Considering the installations at ANKA as an example, the advantages of mirrors and central beam stops for DXRL are presented. Future research work will concentrate on feature sizes much below 1 μm, while the commercialization of DXRL goes in the direction of massive automation, including parallel exposures of several samples in a very wide SR-fan, developing and inspection.

  13. X-ray initiated polymerization of wood impregnants

    NASA Astrophysics Data System (ADS)

    Cleland, Marshall R.; Galloway, Richard A.; Berejka, Anthony J.; Montoney, Daniel; Driscoll, Mark; Smith, Leonard; Scott Larsen, L.

    2009-07-01

    X-rays, derived from a high energy, high-current electron beam (EB), initiated in-situ polymerization of a unique class of monomers that were found to penetrate the cell walls of wood. X-rays initiated an auto-catalytic acrylic polymerization and penetrated through thick pieces of wood. The final cured product having the polymerizate, a polymer, both in the wood cell lumens and in the cell walls is called wood impregnated with a wood-polymer penetrant (WPP). The controlled lower dose rate of X-rays overcame disproportionation encountered when using higher dose-rate electron beam initiation. With X-rays, the in-situ polymerization took place in one exposure of modest dose. With EB, multiple passes were needed to avoid excessive heat build-up and monomer volatilization. Having entered the cell walls of the wood and then being polymerized within the cell walls, these radiation-cured unique monomers imparted outstanding dimensional stability upon exposure of the impregnated wood to humidity cycling. The preferred monomer system was also chemically modified prior to impregnation with agents that would remain in the wood and prevent the growth of fungi and other microbials. This technique differs from historic uses of monomers that merely filled the lumens of the wood (historic wood-polymer composites), which are only suitable for indoor use. The WPP impregnated wood that was either X-ray cured or EB cured demonstrated enhanced structural properties, dimensional stability, and decay resistance.

  14. X-ray Spectroscopy of Cooling Cluster

    SciTech Connect

    Peterson, J.R.; Fabian, A.C.; /Cambridge U., Inst. of Astron.

    2006-01-17

    We review the X-ray spectra of the cores of clusters of galaxies. Recent high resolution X-ray spectroscopic observations have demonstrated a severe deficit of emission at the lowest X-ray temperatures as compared to that expected from simple radiative cooling models. The same observations have provided compelling evidence that the gas in the cores is cooling below half the maximum temperature. We review these results, discuss physical models of cooling clusters, and describe the X-ray instrumentation and analysis techniques used to make these observations. We discuss several viable mechanisms designed to cancel or distort the expected process of X-ray cluster cooling.

  15. Atmospheric electron x-ray spectrometer

    NASA Technical Reports Server (NTRS)

    Feldman, Jason E. (Inventor); George, Thomas (Inventor); Wilcox, Jaroslava Z. (Inventor)

    2002-01-01

    The present invention comprises an apparatus for performing in-situ elemental analyses of surfaces. The invention comprises an atmospheric electron x-ray spectrometer with an electron column which generates, accelerates, and focuses electrons in a column which is isolated from ambient pressure by a:thin, electron transparent membrane. After passing through the membrane, the electrons impinge on the sample in atmosphere to generate characteristic x-rays. An x-ray detector, shaping amplifier, and multi-channel analyzer are used for x-ray detection and signal analysis. By comparing the resultant data to known x-ray spectral signatures, the elemental composition of the surface can be determined.

  16. Method for spatially modulating X-ray pulses using MEMS-based X-ray optics

    DOEpatents

    Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

    2015-03-10

    A method and apparatus are provided for spatially modulating X-rays or X-ray pulses using microelectromechanical systems (MEMS) based X-ray optics. A torsionally-oscillating MEMS micromirror and a method of leveraging the grazing-angle reflection property are provided to modulate X-ray pulses with a high-degree of controllability.

  17. Cellular and molecular level responses after radiofrequency radiation exposure, alone or in combination with x-rays or chemicals. Final report, 1 April 1991-30 September 1994

    SciTech Connect

    Meltz, M.L.; Natarajan, M.; Prasad, A.V.

    1995-02-21

    This project was initiated to explore the potential bioeffects of microwave radiation, alone or in combination with ionizing radiation and chemicals. Over the time period of the project, an automated thermal control system, to be used for maintaining the temperature in tissue culture medium during microwave exposures, was designed, constructed, and software was created. While this was underway during the project period, numerous positive control biological experiments were performed on two different cell types, the Epstein Barr Virus transformed 244B human lymphoblastoid cell, and the freshly isolated peripheral human lymphocyte. The 244B cells were used to address the question of whether a physical agent, ionizing radiation, at low doses where cells would predominantly remain viable, would induce the DNA binding protein NF-kB, and/or four immediate early genes (IEG) (protooncogenes).

  18. Prenatal x-ray and childhood cancer in twins

    SciTech Connect

    Harvey, E.B.

    1983-01-01

    In order to evaluate the causal nature of the relationship between prenatal x-ray exposure and childhood cancer, a case control study was conducted in a population of over 32,000 twins born in the state of Connecticut from 1930-1969 and followed to age 15. Thirty-two incident cancer cases were identified by linking the Connecticut Twin and Tumor registries. Each case was matched with four controls on year of birth, sex, race, and survival. Prenatal x-ray information as well as reproductive, delivery and birth data were obtained from the hospital of birth, the physician providing prenatal care, private radiology groups and interviews with hospital staff. The case control study which obtained exposure information on selected subjects found an increased risk of childhood cancer from prenatal x-ray exposure. The risk associated with radiation exposure was elevated in the following subcategories: mother with history of pregnancy loss, a gravity greater than 1, under 30 years of age, and twins weighing five pounds or more at birth. The results, though based on small numbers, strengthen the association between prenatal x-ray exposure and childhood cancer.

  19. The Effect of X-Ray Absorption Fine Structure in Soft X-ray Astronomical Telescopes

    NASA Astrophysics Data System (ADS)

    Owens, Alan; Denby, Michael; Wells, Alan; Keay, Adam; Graessle, Dale E.; Blake, Richard L.

    1997-02-01

    Recent in-orbit measurements by high resolution soft X-ray telescopes have revealed low-level fine structure in target spectra that cannot be attributed to a celestial source. Ultimately, this can be traced to the ability of the new high spectral resolution silicon detectors to resolve X-ray absorption fine structure (XAFS) produced in the various detection subsystems. Based on measurements taken at the Daresbury Synchrotron Radiation Source (SRS) and the National Synchrotron Light Source (NSLS), we have modeled the full-up response function of the Joint European X-ray Telescope (JET-X), taking into account edge structure generated in the detectors, filters, and mirrors. It is found that unfolding celestial source spectra using a response function in which the detailed edge shapes are calculated from standard absorption cross sections leads to the generation of spectral artifacts at every absorption edge. These in turn produce unacceptably high values of χ2 in model fits for total source fluxes above ~4 × 104 counts. For JET-X, this corresponds to a source strength of ~0.4 millicrab observed for 105 s. Statistically significant ``linelike'' features are introduced into the derived source spectra with amplitudes as great as 10% of the source flux. For JET-X, these features rise above the 3 σ level for integral source exposures above ~5 × 104 source counts. The largest deviations in the residuals arise near 0.5 keV and 2.2 keV and are attributed to XAFS produced in the oxide surface layers of the CCD and the gold reflective surface of the mirrors, respectively. These results are significant for data interpretation tasks with the ASCA, JET-X, XMM, and Advanced X-Ray Astrophysics Facility (AXAF) telescopes.

  20. X-ray phase contrast imaging at MAMI

    NASA Astrophysics Data System (ADS)

    El-Ghazaly, M.; Backe, H.; Lauth, W.; Kube, G.; Kunz, P.; Sharafutdinov, A.; Weber, T.

    2006-05-01

    Experiments have been performed to explore the potential of the low emittance 855MeV electron beam of the Mainz Microtron MAMI for imaging with coherent X-rays. Transition radiation from a micro-focused electron beam traversing a foil stack served as X-ray source with good transverse coherence. Refraction contrast radiographs of low absorbing materials, in particular polymer strings with diameters between 30 and 450μm, were taken with a polychromatic transition radiation X-ray source with a spectral distribution in the energy range between 8 and about 40keV. The electron beam spot size had standard deviation σh = (8.6±0.1)μm in the horizontal and σv = (7.5±0.1)μm in the vertical direction. X-ray films were used as detectors. The source-to-detector distance amounted to 11.4m. The objects were placed in a distance of up to 6m from the X-ray film. Holograms of strings were taken with a beam spot size σv = (0.50±0.05)μm in vertical direction, and a monochromatic X-ray beam of 6keV energy. A good longitudinal coherence has been obtained by the (111) reflection of a flat silicon single crystal in Bragg geometry. It has been demonstrated that a direct exposure CCD chip with a pixel size of 13×13μm^2 provides a highly efficient on-line detector. Contrast images can easily be generated with a complete elimination of all parasitic background. The on-line capability allows a minimization of the beam spot size by observing the smallest visible interference fringe spacings or the number of visible fringes. It has been demonstrated that X-ray films are also very useful detectors. The main advantage in comparison with the direct exposure CCD chip is the resolution. For the Structurix D3 (Agfa) X-ray film the standard deviation of the resolution was measured to be σf = (1.2±0.4)μm, which is about a factor of 6 better than for the direct exposure CCD chip. With the small effective X-ray spot size in vertical direction of σv = (1.2±0.3)μm and a geometrical

  1. X-ray lithography using holographic images

    DOEpatents

    Howells, Malcolm R.; Jacobsen, Chris

    1995-01-01

    A non-contact X-ray projection lithography method for producing a desired X-ray image on a selected surface of an X-ray-sensitive material, such as photoresist material on a wafer, the desired X-ray image having image minimum linewidths as small as 0.063 .mu.m, or even smaller. A hologram and its position are determined that will produce the desired image on the selected surface when the hologram is irradiated with X-rays from a suitably monochromatic X-ray source of a selected wavelength .lambda.. On-axis X-ray transmission through, or off-axis X-ray reflection from, a hologram may be used here, with very different requirements for monochromaticity, flux and brightness of the X-ray source. For reasonable penetration of photoresist materials by X-rays produced by the X-ray source, the wavelength X, is preferably chosen to be no more than 13.5 nm in one embodiment and more preferably is chosen in the range 1-5 nm in the other embodiment. A lower limit on linewidth is set by the linewidth of available microstructure writing devices, such as an electron beam.

  2. X ray imaging microscope for cancer research

    NASA Technical Reports Server (NTRS)

    Hoover, Richard B.; Shealy, David L.; Brinkley, B. R.; Baker, Phillip C.; Barbee, Troy W., Jr.; Walker, Arthur B. C., Jr.

    1991-01-01

    The NASA technology employed during the Stanford MSFC LLNL Rocket X Ray Spectroheliograph flight established that doubly reflecting, normal incidence multilayer optics can be designed, fabricated, and used for high resolution x ray imaging of the Sun. Technology developed as part of the MSFC X Ray Microscope program, showed that high quality, high resolution multilayer x ray imaging microscopes are feasible. Using technology developed at Stanford University and at the DOE Lawrence Livermore National Laboratory (LLNL), Troy W. Barbee, Jr. has fabricated multilayer coatings with near theoretical reflectivities and perfect bandpass matching for a new rocket borne solar observatory, the Multi-Spectral Solar Telescope Array (MSSTA). Advanced Flow Polishing has provided multilayer mirror substrates with sub-angstrom (rms) smoothnesss for the astronomical x ray telescopes and x ray microscopes. The combination of these important technological advancements has paved the way for the development of a Water Window Imaging X Ray Microscope for cancer research.

  3. Evolution of X-ray astronomy

    NASA Technical Reports Server (NTRS)

    Rossj, B.

    1981-01-01

    The evolution of X-ray astronomy up to the launching of the Einstein observatory is presented. The evaluation proceeded through the following major steps: (1) discovery of an extrasolar X-ray source, Sco X-1, orders of magnitude stronger than astronomers believed might exist; (2) identification of a strong X-ray source with the Crab Nebula; (3) identification of Sco X-1 with a faint, peculiar optical object; (4) demonstration that X-ray stars are binary systems, each consisting of a collapsed object accreting matter from an ordinary star; (5) discovery of X-ray bursts; (6) discovery of exceedingly strong X-ray emission from active galaxies, quasars and clusters of galaxies; (7) demonstration that the principal X-ray source is a hot gas filling the space between galaxies.

  4. The Rosat x-ray sky

    NASA Astrophysics Data System (ADS)

    Voges, Wolfgang

    1995-01-01

    The ROSAT (Röntgensatellit) X-ray astronomy satellite has completed the first all-sky x-ray and XUV survey with imaging telescopes. About 60 000 new x-ray and 400 new XUV (1) sources were detected. This contribution will deal with preliminary results from the ROSAT ALL-SKY X-RAY SURVEY. The ROSAT diffuse and point-source x-ray skymaps, the positional accuracy obtained for the x-ray sources, and a few results from correlations performed with available catalogues in various energy bands like the Radio, Infrared, Visible, UV, and hard x-rays as well as identifications from optical follow-up observations will be presented.

  5. Spectral slicing X-ray telescope

    NASA Technical Reports Server (NTRS)

    Hoover, R. B.; Shealy, D.; Chao, S.-H.

    1986-01-01

    Layered synthetic microstructure (LSM) X-ray optics is investigated as a system for coupling a conventional glancing incidence X-ray mirror to a high sensitivity X-ray detector. It is shown that, by the use of figured LSM optics, it is possible to magnify the X-ray image produced by the primary mirrors so as to maintain their high inherent spatial resolution. The results of theoretical and design analyses of several spectral slicing X-ray telescope systems that utilize LSM mirrors of hyperboloidal, spherical, ellipsoidal, and constant optical path aspheric configurations are presented. It is shown that the spherical LSM optics are the preferred configuration, yielding subarcsecond performance over the entire field. The Stanford/Marshall Space Flight Center Rocket X-ray Telescope, which will utilize normal incidence LSM optics to couple a Wolter-Schwarzschild primary mirror to high resolution detectors for solar X-ray/EUV studies, is discussed. Design diagrams are included.

  6. Paediatric x-ray radiation dose reduction and image quality analysis.

    PubMed

    Martin, L; Ruddlesden, R; Makepeace, C; Robinson, L; Mistry, T; Starritt, H

    2013-09-01

    Collaboration of multiple staff groups has resulted in significant reduction in the risk of radiation-induced cancer from radiographic x-ray exposure during childhood. In this study at an acute NHS hospital trust, a preliminary audit identified initial exposure factors. These were compared with European and UK guidance, leading to the introduction of new factors that were in compliance with European guidance on x-ray tube potentials. Image quality was assessed using standard anatomical criteria scoring, and visual grading characteristics analysis assessed the impact on image quality of changes in exposure factors. This analysis determined the acceptability of gradual radiation dose reduction below the European and UK guidance levels. Chest and pelvis exposures were optimised, achieving dose reduction for each age group, with 7%-55% decrease in critical organ dose. Clinicians confirmed diagnostic image quality throughout the iterative process. Analysis of images acquired with preliminary and final exposure factors indicated an average visual grading analysis result of 0.5, demonstrating equivalent image quality. The optimisation process and final radiation doses are reported for Carestream computed radiography to aid other hospitals in minimising radiation risks to children.

  7. X-ray deconvolution microscopy.

    PubMed

    Ehn, Sebastian; Epple, Franz Michael; Fehringer, Andreas; Pennicard, David; Graafsma, Heinz; Noël, Peter; Pfeiffer, Franz

    2016-04-01

    Recent advances in single-photon-counting detectors are enabling the development of novel approaches to reach micrometer-scale resolution in x-ray imaging. One example of such a technology are the MEDIPIX3RX-based detectors, such as the LAMBDA which can be operated with a small pixel size in combination with real-time on-chip charge-sharing correction. This characteristic results in a close to ideal, box-like point spread function which we made use of in this study. The proposed method is based on raster-scanning the sample with sub-pixel sized steps in front of the detector. Subsequently, a deconvolution algorithm is employed to compensate for blurring introduced by the overlap of pixels with a well defined point spread function during the raster-scanning. The presented approach utilizes standard laboratory x-ray equipment while we report resolutions close to 10 μm. The achieved resolution is shown to follow the relationship [Formula: see text] with the pixel-size p of the detector and the number of raster-scanning steps n.

  8. Submicron X-ray diffraction

    SciTech Connect

    MacDowell, Alastair; Celestre, Richard; Tamura, Nobumichi; Spolenak, Ralph; Valek, Bryan; Brown, Walter; Bravman, John; Padmore, Howard; Batterman, Boris; Patel, Jamshed

    2000-08-17

    At the Advanced Light Source in Berkeley the authors have instrumented a beam line that is devoted exclusively to x-ray micro diffraction problems. By micro diffraction they mean those classes of problems in Physics and Materials Science that require x-ray beam sizes in the sub-micron range. The instrument is for instance, capable of probing a sub-micron size volume inside micron sized aluminum metal grains buried under a silicon dioxide insulating layer. The resulting Laue pattern is collected on a large area CCD detector and automatically indexed to yield the grain orientation and deviatoric (distortional) strain tensor of this sub-micron volume. A four-crystal monochromator is then inserted into the beam, which allows monochromatic light to illuminate the same part of the sample. Measurement of diffracted photon energy allows for the determination of d spacings. The combination of white and monochromatic beam measurements allow for the determination of the total strain/stress tensor (6 components) inside each sub-micron sized illuminated volume of the sample.

  9. X-ray deconvolution microscopy

    PubMed Central

    Ehn, Sebastian; Epple, Franz Michael; Fehringer, Andreas; Pennicard, David; Graafsma, Heinz; Noël, Peter; Pfeiffer, Franz

    2016-01-01

    Recent advances in single-photon-counting detectors are enabling the development of novel approaches to reach micrometer-scale resolution in x-ray imaging. One example of such a technology are the MEDIPIX3RX-based detectors, such as the LAMBDA which can be operated with a small pixel size in combination with real-time on-chip charge-sharing correction. This characteristic results in a close to ideal, box-like point spread function which we made use of in this study. The proposed method is based on raster-scanning the sample with sub-pixel sized steps in front of the detector. Subsequently, a deconvolution algorithm is employed to compensate for blurring introduced by the overlap of pixels with a well defined point spread function during the raster-scanning. The presented approach utilizes standard laboratory x-ray equipment while we report resolutions close to 10 μm. The achieved resolution is shown to follow the relationship pn with the pixel-size p of the detector and the number of raster-scanning steps n. PMID:27446649

  10. X-ray lasing - Theory

    NASA Astrophysics Data System (ADS)

    1985-11-01

    The theoretical basis of lasing at very short wavelengths is discussed, and lasing at soft-X-ray (4-50 nm) wavelengths using the electron-collisional excitation scheme is successfully demonstrated. In research at LLNL, thin foils of selenium and yttrium are irradiated with laser light to generate a roughly cylindrical plasma containing neon-like ions. Excitation of ground state 2p electrons to the 3p state in the lasant medium is followed by very fast radioactive decay out of the 3s state, creating a population inversion between the 3s and 3p states. Stimulated X-ray emission is initiated by slower spontaneous decay from a 3p to 3s state. Design goals are to produce a plasma with a flat electron density of approximately 5 x 10 to the 20th/cu cm, a flat temperature profile, a scale length of at least 100 microns, and a population inversion lasting at least the 100 ps necessary to produce a significant gain. Good correlation is seen between experimental data and LANEX and XRASER theoretical modeling predictions over large variations in intensity, pulse length, and probing times. No explanation is found for the weakness of the J = 0 to J = 1 lasing transition line at 18.3 nm.

  11. X-ray omni microscopy.

    PubMed

    Paganin, D; Gureyev, T E; Mayo, S C; Stevenson, A W; Nesterets, Ya I; Wilkins, S W

    2004-06-01

    The science of wave-field phase retrieval and phase measurement is sufficiently mature to permit the routine reconstruction, over a given plane, of the complex wave-function associated with certain coherent forward-propagating scalar wave-fields. This reconstruction gives total knowledge of the information that has been encoded in the complex wave-field by passage through a sample of interest. Such total knowledge is powerful, because it permits the emulation in software of the subsequent action of an infinite variety of coherent imaging systems. Such 'virtual optics', in which software forms a natural extension of the 'hardware optics' in an imaging system, may be useful in contexts such as quantitative atom and X-ray imaging, in which optical elements such as beam-splitters and lenses can be realized in software rather than optical hardware. Here, we develop the requisite theory to describe such hybrid virtual-physical imaging systems, which we term 'omni optics' because of their infinite flexibility. We then give an experimental demonstration of these ideas by showing that a lensless X-ray point projection microscope can, when equipped with the appropriate software, emulate an infinite variety of optical imaging systems including those which yield interferograms, Zernike phase contrast, Schlieren imaging and diffraction-enhanced imaging.

  12. X-ray population exposure from projection radiology and computed tomography in Emilia-Romagna from 2001 to 2010: comparison of ICRP 60 and ICRP 103 weighting factors.

    PubMed

    Compagnone, Gaetano; Angelini, Paola; Domenichelli, Sara

    2014-05-01

    This paper shows the trends from 2001 to 2010 of per caput and collective effective dose (S) to the Emilia-Romagna population due to radiation exposure from projection radiology (PR) and computed tomography (CT), calculated according to both ICRP60 and ICRP103 tissue weighting factors. The frequency of examinations and dose calculations were based on data provided directly by Emilia-Romagna Health Trusts. In particular, effective doses were evaluated using the tissue weighting (w T) factors reported both in ICRP60 (w T,60) and in ICRP103 (w T,103). A decrease in the frequency of PR skull examinations and an increase in the frequency of mammography, CT of the abdomen, chest, and head-neck were found during the decade. In 2010, the PR/CT procedures contributed 75.4 %/24.6 % to examination frequency and approximately 10 %/90 % to dose; S was 6,169.2 man Sv when w T,60 was used and 5,855.1-6,665.5 man Sv when w T,103 in two different mathematical models was utilised. Dose estimates pre- and post-ICRP103 must be compared carefully, because changes due to different radiological practices could be confused with changes due to the use of different w T's. In general, dose evaluations with the use of w T,60 until 2007 and w T,103 from 2008 seem to be consistent and coherent.

  13. Soft x-ray imaging by a commercial solid-state television camera

    NASA Astrophysics Data System (ADS)

    Matsushima, Isao; Koyama, Kazuyoshi; Tanimoto, Mitsumori; Yano, Masaaki

    1987-04-01

    A commerical, solid-state television camera has been used to record images of soft x radiation (0.8-12 keV). The performance of the camera is theoretically analyzed and experimentally evaluated compared with an x-ray photographic film (Kodak direct exposure film). In the application, the camera has been used to provide image patterns of x rays from laser-produced plasmas. It is demonstrated that the camera has several advantages over x-ray photographic film.

  14. A study of the discrepant QSO X-ray luminosity function from the HEAO-2 data archive

    NASA Technical Reports Server (NTRS)

    Margon, B.

    1986-01-01

    Sensitive X-ray information for approximately 90 previously uncataloged Quasi-Stellar Objects (QSOs) in the redshift range 1.8 is less than or equal to z which is less than or equal to 3. Even with the longest esixting Einstein Observatory X-ray exposures, only 25% of these objects are positively detected in X-rays. The data were used to investigate the ensemble X-ray properties of high redshift QSOs, and the QSO population in general.

  15. X-Ray Scan Detection for Cargo Integrity

    SciTech Connect

    Valencia, Juan D.; Miller, Steven D.

    2011-04-18

    ABSTRACT The increase of terrorism and its global impact has made the determination of the contents of cargo containers a necessity. Existing technology allows non-intrusive inspections to determine the contents of a container rapidly and accurately. However, some cargo shipments are exempt from such inspections. Hence, there is a need for a technology that enables rapid and accurate means of detecting whether such containers were non-intrusively inspected. Non-intrusive inspections are most commonly performed utilizing high powered X-ray equipment. The challenge is creating a device that can detect short duration X-ray scans while maintaining a portable, battery powered, low cost, and easy to use platform. The Pacific Northwest National Laboratory (PNNL) has developed a methodology and prototype device focused on this challenge. The prototype, developed by PNNL, is a battery powered electronic device that continuously measures its X-ray and Gamma exposure, calculates the dose equivalent rate, and makes a determination of whether the device has been exposed to the amount of radiation experienced during an X-ray inspection. Once an inspection is detected, the device will record a timestamp of the event and relay the information to authorized personnel via a visual alert, USB connection, and/or wireless communication. The results of this research demonstrate that PNNL’s prototype device can be effective at determining whether a container was scanned by X-ray equipment typically used for cargo container inspections. This paper focuses on laboratory measurements and test results acquired with the PNNL prototype device using several X-ray radiation levels. Keywords: Radiation, Scan, X-ray, Gamma, Detection, Cargo, Container, Wireless, RF

  16. X-Ray Protection Standards for Home Television Receivers.

    ERIC Educational Resources Information Center

    National Council on Radiation Protection and Measurements, Washington, DC.

    Levels of X-Ray emission and exposure from home television receivers are being questioned and found greater than previous public health and safety cautions and measurement limits have suggested. The latest changes in television components, designs, function, and manufacturing, have caused equipment standards and the effects of radiation to be…

  17. X-Ray Protection Standards for Home Television Receivers.

    ERIC Educational Resources Information Center

    National Council on Radiation Protection and Measurements, Washington, DC.

    Levels of X-Ray emission and exposure from home television receivers are being questioned and found greater than previous public health and safety cautions and measurement limits have suggested. The latest changes in television components, designs, function, and manufacturing, have caused equipment standards and the effects of radiation to be…

  18. X-Ray Attenuation Cell

    SciTech Connect

    Ryutov, D.; Toor, A.

    2000-03-03

    To minimize the pulse-to-pulse variation, the LCLS FEL must operate at saturation, i.e. 10 orders of magnitude brighter spectral brilliance than 3rd-generation light sources. At this intensity, ultra-high vacuums and windowless transport are required. Many of the experiments, however, will need to be conducted at a much lower intensity thereby requiring a reliable means to reduce the x-ray intensity by many orders of magnitude without increasing the pulse-to-pulse variation. In this report we consider a possible solution for controlled attenuation of the LCLS x-ray radiation. We suggest using for this purpose a windowless gas-filled cell with the differential pumping. Although this scheme is easily realizable in principle, it has to be demonstrated that the attenuator can be made short enough to be practical and that the gas loads delivered to the vacuum line of sight (LOS) are acceptable. We are not going to present a final, optimized design. Instead, we will provide a preliminary analysis showing that the whole concept is robust and is worth further study. The spatial structure of the LCLS x-ray pulse at the location of the attenuator is shown in Fig. 1. The central high-intensity component, due to the FEL, has a FWHM of {approx}100 {micro}m. A second component, due to the undulator's broad band spontaneous radiation is seen as a much lower intensity ''halo'' with a FWHM of 1 mm. We discuss two versions of the attenuation cell. The first is directed towards a controlled attenuation of the FEL up to the 4 orders of magnitude in the intensity, with the spontaneous radiation halo being eliminated by collimators. In the second version, the spontaneous radiation is not sacrificed but the FEL component (as well as the first harmonic of the spontaneous radiation) gets attenuated by a more modest factor up to 100. We will make all the estimates assuming that the gas used in the attenuator is Xenon and that the energy of the FEL is 8.25 keV. At lower FEL energies the

  19. Observational Aspects of Hard X-ray Polarimetry

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Tanmoy

    2016-04-01

    of such hard X-ray telescopes, which may provide sensitive polarization measurements due to flux concentration in hard X-rays with a very low background. On the other hand, such a configuration ensures implementation of an optimized geometry close to an ideal one for the Compton polarimeters. In this context, we initiated the development of a focal plane Compton polarimeter, consisting of a plastic scatterer surrounded by a cylindrical array of CsI(Tl) scintillators. Geant-4 simulations of the planned configuration estimates 1% MDP for a 100 mCrab source in 1 million seconds of exposure. Sensitivity of the instrument is found to be critically dependent on the lower energy detection limit of the plastic scatterer; lower the threshold, better is the sensitivity. In the actual experiment, the plastic is readout by a photomultiplier tube procured from Saint-Gobain. We carried out extensive experiments to characterize the plastic especially for lower energy depositions. The CsI(Tl) scintillators are readout by Si photomultipliers (SiPM). SiPMs are small in size and robust and therefore provide the compactness necessary for the designing of focal plane detectors. Each of the CsI(Tl)-SiPM systems was characterized precisely to estimate their energy threshold and detection probability along the length of the scintillators away from SiPM. Finally, we integrated the Compton polarimeter and tested its response to polarized and unpolarized radiation and compared the experimental results with Geant-4 simulation. Despite the growing realization of the scientific values of X-ray polarimetry and the efforts in developing sensitive X-ray polarimeters, there has not been a single dedicated X-ray polarimetry mission planned in near future. In this scenario, it is equally important to attempt polarization measurements from the existing or planned instruments which are not meant for X-ray polarization measurements but could be sensitive to it. There have been several attempts in past in

  20. Mobile X-ray generators: a review.

    PubMed

    Evans, S A; Harris, L; Lawinski, C P; Hendra, I R

    1985-01-01

    Mobile X-ray generators vary widely in design, cost and radiographic performance and the new designs of recent years have led to the introduction of jargon. Such terms as 'capacitator discharge' and 'modicum frequency' can give rise to confusion regarding operating technique. This review classifies the mobiles into three distinct categories. Simple rules are presented to enable an operator to transfer exposure factors from one category to another, and an analysis of the relative merits of each category is provided. Part 1 provides a description of the categories available, a broad explanation of the principles involved and discusses the radiographic use. Throughout the text certain terms are given in italics when first used in that particular description and Part 2 gives full explanations of these terms in the context of Part 1.

  1. X-ray Multimodal Tomography Using Speckle-Vector Tracking

    NASA Astrophysics Data System (ADS)

    Berujon, Sebastien; Ziegler, Eric

    2016-04-01

    We demonstrate computerized tomography (CT) reconstructions from absorption, phase, and dark-field signals obtained from scans acquired when the x-ray probe light is modulated with speckle. Two different interlaced schemes are proposed to reduce the number of sample exposures. First, the already demonstrated x-ray speckle-vector tracking (XSVT) concept for projection imaging allows the three signal CT reconstructions from multiple images per projection. Second, a modified XSVT approach is shown to provide absorption and phase reconstructions, this time from a single image per angular projection. Reconstructions from data obtained at a synchrotron facility emphasize the potential of the approaches for the imaging of complex samples.

  2. Phase contrast hard x-ray microscopy with submicron resolution

    SciTech Connect

    Lagomarsino, S.; Cedola, A.; Cloetens, P.; Di Fonzo, S.; Jark, W.; Soullie, G.; Riekel, C.

    1997-11-01

    In this letter we present a hard x-ray phase contrast microscope based on the divergent and coherent beam exiting an x-ray waveguide. It uses lensless geometrical projection to magnify spatial variations in optical path length more than 700 times. Images of a nylon fiber and a gold test pattern were obtained with a resolution of 0.14 {mu}m in one direction. Exposure times as short as 0.1 s gave already visible contrast, opening the way to high resolution, real time studies. {copyright} {ital 1997 American Institute of Physics.}

  3. Compact water-window transmission X-ray microscopy.

    PubMed

    Berglund, M; Rymell, L; Peuker, M; Wilhein, T; Hertz, H M

    2000-03-01

    We demonstrate sub-100 nm resolution water-window soft X-ray full-field transmission microscopy with a compact system. The microscope operates at lambda = 3.37 nm and is based on a 100 Hz table-top regenerative debris-free droplet-target laser-plasma X-ray source in combination with normal-incidence multilayer condenser optics for sample illumination. High-spatial-resolution imaging is performed with a 7.3% efficiency nickel zone plate and a 1024 x 1024 pixel CCD detector. Images of dry test samples are recorded with exposure times of a few minutes and show features smaller than 60 nm.

  4. Characterization and cross calibration of Agfa D4, D7, and D8 and Kodak SR45 x-ray films against direct exposure film at 4.0-5.5 keV

    SciTech Connect

    Lanier, N.E.; Cowan, J.S.; Workman, J.

    2006-04-15

    Kodak direct exposure film (DEF) [B. L. Henke et al., J. Opt. Soc. Am. B 3, 1540 (1986)] has been the standard for moderate energy (1-10 keV) x-ray diagnostic applications among the high-energy-density and inertial confinement fusion research communities. However, market forces have prompted Kodak to discontinue production of DEF, leaving these specialized communities searching for a replacement. We have conducted cross-calibration experiments and film characterizations on five possible substitutes for Kodak DEF. The film types studied were Kodak's Biomax MR (BMR) and SR45 along with Agfa's D8, D7, and D4sc. None of the films tested matched the speed of DEF. BMR and D8 were closest but D8 exhibited lower noise, with superior resolution and dynamic range. Agfa D7, Agfa D4sc, and Kodak SR45 were significantly less sensitive than BMR and D8, however, the improvements they yielded in resolution and dynamic range warrant their use if experimental constraints allow.

  5. Characterization and cross calibration of Agfa D4, D7, and D8 and Kodak SR45 x-ray films against direct exposure film at 4.0-5.5 keV

    NASA Astrophysics Data System (ADS)

    Lanier, N. E.; Cowan, J. S.; Workman, J.

    2006-04-01

    Kodak direct exposure film (DEF) [B. L. Henke et al., J. Opt. Soc. Am. B 3, 1540 (1986)] has been the standard for moderate energy (1-10keV) x-ray diagnostic applications among the high-energy-density and inertial confinement fusion research communities. However, market forces have prompted Kodak to discontinue production of DEF, leaving these specialized communities searching for a replacement. We have conducted cross-calibration experiments and film characterizations on five possible substitutes for Kodak DEF. The film types studied were Kodak's Biomax MR (BMR) and SR45 along with Agfa's D8, D7, and D4sc. None of the films tested matched the speed of DEF. BMR and D8 were closest but D8 exhibited lower noise, with superior resolution and dynamic range. Agfa D7, Agfa D4sc, and Kodak SR45 were significantly less sensitive than BMR and D8, however, the improvements they yielded in resolution and dynamic range warrant their use if experimental constraints allow.

  6. Compact Stellar X-ray Sources

    NASA Astrophysics Data System (ADS)

    Lewin, Walter; van der Klis, Michiel

    2010-11-01

    1. Accreting neutron stars and black holes: a decade of discoveries D. Psaltis; 2. Rapid X-ray variability M. van der Klis; 3. New views of thermonuclear bursts T. Strohmayer and L. Bildsten; 4. Black hole binaries J. McClintock and R. Remillard; 5. Optical, ultraviolet and infrared observations of X-ray binaries P. Charles and M. Coe; 6. Fast X-ray transients and X-ray flashes J. Heise and J. in 't Zand; 7. Isolated neutron stars V. Kaspi, M. Roberts and A. Harding; 8. Globular cluster X-ray sources F. Verbunt and W. Lewin; 9. Jets from X-ray binaries R. Fender; 10. X-Rays from cataclysmic variables E. Kuulkers, A. Norton, A. Schwope and B. Warner; 11. Super soft sources P. Kahabka and E. van den Heuvel; 12. Compact stellar X-ray sources in normal galaxies G. Fabbiano and N. White; 13. Accretion in compact binaries A. King; 14. Soft gamma repeaters and anomalous X-ray pulsars: magnetar candidates P. Woods and C. Thompson; 15. Cosmic gamma-ray bursts, their afterglows, and their host galaxies K. Hurley, R. Sari and S. Djorgovski; 16. Formation and evolution of compact stellar X-ray sources T. Tauris and E. van den Heuvel.

  7. Compact Stellar X-ray Sources

    NASA Astrophysics Data System (ADS)

    Lewin, Walter H. G.; van der Klis, Michiel

    2006-04-01

    1. Accreting neutron stars and black holes: a decade of discoveries D. Psaltis; 2. Rapid X-ray variability M. van der Klis; 3. New views of thermonuclear bursts T. Strohmayer and L. Bildsten; 4. Black hole binaries J. McClintock and R. Remillard; 5. Optical, ultraviolet and infrared observations of X-ray binaries P. Charles and M. Coe; 6. Fast X-ray transients and X-ray flashes J. Heise and J. in 't Zand; 7. Isolated neutron stars V. Kaspi, M. Roberts and A. Harding; 8. Globular cluster X-ray sources F. Verbunt and W. Lewin; 9. Jets from X-ray binaries R. Fender; 10. X-Rays from cataclysmic variables E. Kuulkers, A. Norton, A. Schwope and B. Warner; 11. Super soft sources P. Kahabka and E. van den Heuvel; 12. Compact stellar X-ray sources in normal galaxies G. Fabbiano and N. White; 13. Accretion in compact binaries A. King; 14. Soft gamma repeaters and anomalous X-ray pulsars: magnetar candidates P. Woods and C. Thompson; 15. Cosmic gamma-ray bursts, their afterglows, and their host galaxies K. Hurley, R. Sari and S. Djorgovski; 16. Formation and evolution of compact stellar X-ray sources T. Tauris and E. van den Heuvel.

  8. Controlling X-rays With Light

    SciTech Connect

    Glover, Ernie; Hertlein, Marcus; Southworth, Steve; Allison, Tom; van Tilborg, Jeroen; Kanter, Elliot; Krassig, B.; Varma, H.; Rude, Bruce; Santra, Robin; Belkacem, Ali; Young, Linda

    2010-08-02

    Ultrafast x-ray science is an exciting frontier that promises the visualization of electronic, atomic and molecular dynamics on atomic time and length scales. A largelyunexplored area of ultrafast x-ray science is the use of light to control how x-rays interact with matter. In order to extend control concepts established for long wavelengthprobes to the x-ray regime, the optical control field must drive a coherent electronic response on a timescale comparable to femtosecond core-hole lifetimes. An intense field is required to achieve this rapid response. Here an intense optical control pulse isobserved to efficiently modulate photoelectric absorption for x-rays and to create an ultrafast transparency window. We demonstrate an application of x-ray transparencyrelevant to ultrafast x-ray sources: an all-photonic temporal cross-correlation measurement of a femtosecond x-ray pulse. The ability to control x-ray/matterinteractions with light will create new opportunities at current and next-generation x-ray light sources.

  9. Controlling x-rays with light.

    SciTech Connect

    Glover, T. E.; Hertlein, M. P.; Southworth, S. H.; Allison, T. K.; van Tilborg, J.; Kanter, E. P.; Krassig, B.; Varma, H. R.; Rude, B.; Santra, R.; Belkacem, A.; Young, L.; Chemical Sciences and Engineering Division; LBNL; Univ. of California at Berkley; Univ. of Chicago

    2010-01-01

    Ultrafast X-ray science is an exciting frontier that promises the visualization of electronic, atomic and molecular dynamics on atomic time and length scales. A largely unexplored area of ultrafast X-ray science is the use of light to control how X-rays interact with matter. To extend control concepts established for long-wavelength probes to the X-ray regime, the optical control field must drive a coherent electronic response on a timescale comparable to femtosecond core-hole lifetimes. An intense field is required to achieve this rapid response. Here, an intense optical control pulse is observed to efficiently modulate photoelectric absorption for X-rays and to create an ultrafast transparency window. We demonstrate an application of X-ray transparency relevant to ultrafast X-ray sources: an all-photonic temporal cross-correlation measurement of a femtosecond X-ray pulse. The ability to control X-ray-matter interactions with light will create new opportunities for present and next-generation X-ray light sources.

  10. Controlling X-rays with light

    NASA Astrophysics Data System (ADS)

    Glover, T. E.; Hertlein, M. P.; Southworth, S. H.; Allison, T. K.; van Tilborg, J.; Kanter, E. P.; Krässig, B.; Varma, H. R.; Rude, B.; Santra, R.; Belkacem, A.; Young, L.

    2010-01-01

    Ultrafast X-ray science is an exciting frontier that promises the visualization of electronic, atomic and molecular dynamics on atomic time and length scales. A largely unexplored area of ultrafast X-ray science is the use of light to control how X-rays interact with matter. To extend control concepts established for long-wavelength probes to the X-ray regime, the optical control field must drive a coherent electronic response on a timescale comparable to femtosecond core-hole lifetimes. An intense field is required to achieve this rapid response. Here, an intense optical control pulse is observed to efficiently modulate photoelectric absorption for X-rays and to create an ultrafast transparency window. We demonstrate an application of X-ray transparency relevant to ultrafast X-ray sources: an all-photonic temporal cross-correlation measurement of a femtosecond X-ray pulse. The ability to control X-ray-matter interactions with light will create new opportunities for present and next-generation X-ray light sources.

  11. Industrial X-Ray Imaging

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In 1990, Lewis Research Center jointly sponsored a conference with the U.S. Air Force Wright Laboratory focused on high speed imaging. This conference, and early funding by Lewis Research Center, helped to spur work by Silicon Mountain Design, Inc. to break the performance barriers of imaging speed, resolution, and sensitivity through innovative technology. Later, under a Small Business Innovation Research contract with the Jet Propulsion Laboratory, the company designed a real-time image enhancing camera that yields superb, high quality images in 1/30th of a second while limiting distortion. The result is a rapidly available, enhanced image showing significantly greater detail compared to image processing executed on digital computers. Current applications include radiographic and pathology-based medicine, industrial imaging, x-ray inspection devices, and automated semiconductor inspection equipment.

  12. Diffractive X-Ray Telescopes

    NASA Technical Reports Server (NTRS)

    Skinner, Gerald K.

    2010-01-01

    Diffractive X-ray telescopes, using zone plates, phase Fresnel lenses, or related optical elements have the potential to provide astronomers with true imaging capability with resolution many orders of magnitude better than available in any other waveband. Lenses that would be relatively easy to fabricate could have an angular resolution of the order of micro-arc-seconds or even better, that would allow, for example, imaging of the distorted spacetime in the immediate vicinity of the super-massive black holes in the center of active galaxies. What then is precluding their immediate adoption? Extremely long focal lengths, very limited bandwidth, and difficulty stabilizing the image are the main problems. The history, and status of the development of such lenses is reviewed here and the prospects for managing the challenges that they present are discussed.

  13. X-ray phase contrast for CO2 microangiography

    NASA Astrophysics Data System (ADS)

    Lundström, U.; Larsson, D. H.; Burvall, A.; Takman, P. A. C.; Scott, L.; Brismar, H.; Hertz, H. M.

    2012-05-01

    We demonstrate a laboratory method for imaging small blood vessels using x-ray propagation-based phase-contrast imaging and carbon dioxide (CO2) gas as a contrast agent. The limited radiation dose in combination with CO2 being clinically acceptable makes the method promising for small-diameter vascular visualization. We investigate the possibilities and limitations of the method for small-animal angiography and compare it with conventional absorption-based x-ray angiography. Photon noise in absorption-contrast imaging prevents visualization of blood vessels narrower than 50 µm at the highest radiation doses compatible with living animals, whereas our simulations and experiments indicate the possibility of visualizing 20 µm vessels at radiation doses as low as 100 mGy. Experimental computed tomography of excised rat kidney shows blood vessels of diameters down to 60 µm with improved image quality compared to absorption-based methods. With our present prototype x-ray source, the acquisition time for a tomographic dataset is approximately 1 h, which is long compared to the 1-20 min common for absorption-contrast micro-CT systems. Further development of the liquid-metal-jet microfocus x-ray sources used here and high-resolution x-ray detectors shows promise to reduce exposure times and make this high-resolution method practical for imaging of living animals.

  14. Method and apparatus for micromachining using hard X-rays

    DOEpatents

    Siddons, David Peter; Johnson, Erik D.; Guckel, Henry; Klein, Jonathan L.

    1997-10-21

    An X-ray source such as a synchrotron which provides a significant spectral content of hard X-rays is used to expose relatively thick photoresist such that the portions of the photoresist at an exit surface receive at least a threshold dose sufficient to render the photoresist susceptible to a developer, while the entrance surface of the photoresist receives an exposure which does not exceed a power limit at which destructive disruption of the photoresist would occur. The X-ray beam is spectrally shaped to substantially eliminate lower energy photons while allowing a substantial flux of higher energy photons to pass through to the photoresist target. Filters and the substrate of the X-ray mask may be used to spectrally shape the X-ray beam. Machining of photoresists such as polymethylmethacrylate to micron tolerances may be obtained to depths of several centimeters, and multiple targets may be exposed simultaneously. The photoresist target may be rotated and/or translated in the beam to form solids of rotation and other complex three-dimensional structures.

  15. Method and apparatus for micromachining using hard X-rays

    DOEpatents

    Siddons, D.P.; Johnson, E.D.; Guckel, H.; Klein, J.L.

    1997-10-21

    An X-ray source such as a synchrotron which provides a significant spectral content of hard X-rays is used to expose relatively thick photoresist such that the portions of the photoresist at an exit surface receive at least a threshold dose sufficient to render the photoresist susceptible to a developer, while the entrance surface of the photoresist receives an exposure which does not exceed a power limit at which destructive disruption of the photoresist would occur. The X-ray beam is spectrally shaped to substantially eliminate lower energy photons while allowing a substantial flux of higher energy photons to pass through to the photoresist target. Filters and the substrate of the X-ray mask may be used to spectrally shape the X-ray beam. Machining of photoresists such as polymethylmethacrylate to micron tolerances may be obtained to depths of several centimeters, and multiple targets may be exposed simultaneously. The photoresist target may be rotated and/or translated in the beam to form solids of rotation and other complex three-dimensional structures. 21 figs.

  16. The Deep Look at the Hard X-Ray Sky: The Swift-INTEGRAL X-Ray (SIX) Survey

    NASA Astrophysics Data System (ADS)

    Bottacini, Eugenio; Ajello, Marco; Greiner, Jochen

    2012-08-01

    The supermassive black holes at the center of active galactic nuclei (AGNs) are surrounded by obscuring matter that can block nuclear radiation. Depending on the amount of blocked radiation, the flux from the AGN can be too faint to be detected by currently flying hard X-ray (above 15 keV) missions. At these energies only ~1% of the intensity of the cosmic X-ray background (CXB) can be resolved into point-like sources that are AGNs. In this work, we address the question of undetected sources contributing to the CXB with a very sensitive and new hard X-ray survey: the Swift-INTEGRAL X-ray survey, which is obtained with the new approach of combining the Swift/BAT and INTEGRAL/IBIS X-ray observations. We merge the observations of both missions, which enhances the exposure time and reduces systematic uncertainties. As a result, we obtain a new survey over a wide sky area of 6200 deg2 that is more sensitive than the surveys of Swift/BAT or INTEGRAL/IBIS alone. Our sample comprises 113 sources: 86 AGNs (Seyfert-like and blazars), 5 galaxies, 2 clusters of galaxies, 3 Galactic sources, 3 previously detected unidentified X-ray sources, and 14 unidentified sources. The scientific outcome from the study of the sample has been properly addressed to study the evolution of AGNs at redshift below 0.4. We do not find any evolution using the 1/V max method. Our sample of faint sources is a suitable target for the new generation hard X-ray telescopes with focusing techniques.

  17. THE DEEP LOOK AT THE HARD X-RAY SKY: THE SWIFT-INTEGRAL X-RAY (SIX) SURVEY

    SciTech Connect

    Bottacini, Eugenio; Ajello, Marco

    2012-08-01

    The supermassive black holes at the center of active galactic nuclei (AGNs) are surrounded by obscuring matter that can block nuclear radiation. Depending on the amount of blocked radiation, the flux from the AGN can be too faint to be detected by currently flying hard X-ray (above 15 keV) missions. At these energies only {approx}1% of the intensity of the cosmic X-ray background (CXB) can be resolved into point-like sources that are AGNs. In this work, we address the question of undetected sources contributing to the CXB with a very sensitive and new hard X-ray survey: the Swift-INTEGRAL X-ray survey, which is obtained with the new approach of combining the Swift/BAT and INTEGRAL/IBIS X-ray observations. We merge the observations of both missions, which enhances the exposure time and reduces systematic uncertainties. As a result, we obtain a new survey over a wide sky area of 6200 deg{sup 2} that is more sensitive than the surveys of Swift/BAT or INTEGRAL/IBIS alone. Our sample comprises 113 sources: 86 AGNs (Seyfert-like and blazars), 5 galaxies, 2 clusters of galaxies, 3 Galactic sources, 3 previously detected unidentified X-ray sources, and 14 unidentified sources. The scientific outcome from the study of the sample has been properly addressed to study the evolution of AGNs at redshift below 0.4. We do not find any evolution using the 1/V{sub max} method. Our sample of faint sources is a suitable target for the new generation hard X-ray telescopes with focusing techniques.

  18. A carbon nanotube based x-ray detector

    NASA Astrophysics Data System (ADS)

    Boucher, Richard A.; Bauch, Jürgen; Wünsche, Dietmar; Lackner, Gerhard; Majumder, Anindya

    2016-11-01

    X-ray detectors based on metal-oxide semiconductor field effect transistors couple instantaneous measurement with high accuracy. However, they only have a limited measurement lifetime because they undergo permanent degradation due to x-ray beam exposure. A field effect transistor based on carbon nanotubes (CNTs), however, overcomes this drawback of permanent degradation, because it can be reset into its starting state after being exposed to the x-ray beam. In this work the CNTs were deposited using a dielectrophoresis method on SiO2 coated p-type (boron-doped) Si substrates. For the prepared devices a best gate voltage shift of 244 V Gy-1 and a source-drain current sensitivity of 382 nA Gy-1 were achieved. These values are larger than those reached by the currently used MOSFET based devices.

  19. Soft x-ray interferometry

    SciTech Connect

    Not Available

    1993-09-01

    The purpose of the soft x-ray interferometry workshop held at Lawrence Berkeley Laboratory was to discuss with the scientific community the proposed technical design of the soft x-ray Fourier-transform spectrometer being developed at the ALS. Different design strategies for the instrument`s components were discussed, as well as detection methods, signal processing issues, and how to meet the manufacturing tolerances that are necessary for the instrument to achieve the desired levels of performance. Workshop participants were encouraged to report on their experiences in the field of Fourier transform spectroscopy. The ALS is developing a Fourier transform spectrometer that is intended to operate up to 100 eV. The motivation is solely improved resolution and not the throughput (Jaquinot) or multiplex (Fellgett) advantage, neither of which apply for the sources and detectors used in this spectral range. The proposed implementation of this is via a Mach-Zehnder geometry that has been (1) distorted from a square to a rhombus to get grazing incidence of a suitable angle for 100 eV and (2) provided with a mirror-motion system to make the path difference between the interfering beams tunable. The experiment consists of measuring the emergent light intensity (I(x)) as a function of the path difference (x). The resolving power of the system is limited by the amount of path difference obtainable that is 1 cm (one million half-waves at 200{angstrom} wavelength) in the design thus allowing a resolving power of one million. The free spectral range of the system is limited by the closeness with which the function I(x) is sampled. It is proposed to illuminate a helium absorption cell with roughly 1%-band-width light from a monochromator thus allowing one hundred aliases without spectral overlap even for sampling of I(x) at one hundredth of the Nyquist frequency.

  20. Acute health effects after exposure to chlorine gas released after a train derailment.

    PubMed

    Van Sickle, David; Wenck, Mary Anne; Belflower, Amy; Drociuk, Dan; Ferdinands, Jill; Holguin, Fernando; Svendsen, Erik; Bretous, Lena; Jankelevich, Shirley; Gibson, James J; Garbe, Paul; Moolenaar, Ronald L

    2009-01-01

    In January 2005, a train derailment on the premises of a textile mill in South Carolina released 42 to 60 tons of chlorine gas in the middle of a small town. Medical records and autopsy reports were reviewed to describe the clinical presentation, hospital course, and pathology observed in persons hospitalized or deceased as a result of chlorine gas exposure. Eight persons died before reaching medical care; of the 71 persons hospitalized for acute health effects as a result of chlorine exposure, 1 died in the hospital. The mean age of the hospitalized persons was 40 years (range, 4 months-76 years); 87% were male. The median duration of hospitalization was 4 days (range, 1-29 days). Twenty-five (35%) persons were admitted to the intensive care unit; the median length of stay was 3 days. Many surviving victims developed significant pulmonary signs and severe airway inflammation; 41 (58%) hospitalized persons met PO2/FiO2 criteria for acute respiratory distress syndrome or acute lung injury. During their hospitalization, 40 (57%) developed abnormal x-ray findings, 74% of those within the first day. Hypoxia on room air and PO2/FiO2 ratio predicted severity of outcome as assessed by the duration of hospitalization and the need for intensive care support. This community release of chlorine gas caused widespread exposure and resulted in significant acute health effects and substantial health care requirements. Pulse oximetry and arterial blood gas analysis provided early indications of outcome severity.

  1. Acute health effects after exposure to chlorine gas released after a train derailment⋆

    PubMed Central

    Van Sickle, David; Wenck, Mary Anne; Belflower, Amy; Drociuk, Dan; Ferdinands, Jill; Holguin, Fernando; Svendsen, Erik; Bretous, Lena; Jankelevich, Shirley; Gibson, James J.; Garbe, Paul; Moolenaar, Ronald L.

    2015-01-01

    In January 2005, a train derailment on the premises of a textile mill in South Carolina released 42 to 60 tons of chlorine gas in the middle of a small town. Medical records and autopsy reports were reviewed to describe the clinical presentation, hospital course, and pathology observed in persons hospitalized or deceased as a result of chlorine gas exposure. Eight persons died before reaching medical care; of the 71 persons hospitalized for acute health effects as a result of chlorine exposure, 1 died in the hospital. The mean age of the hospitalized persons was 40 years (range, 4 months-76 years); 87% were male. The median duration of hospitalization was 4 days (range, 1-29 days). Twenty-five (35%) persons were admitted to the intensive care unit; the median length of stay was 3 days. Many surviving victims developed significant pulmonary signs and severe airway inflammation; 41 (58%) hospitalized persons met Po2/Fio2 criteria for acute respiratory distress syndrome or acute lung injury. During their hospitalization, 40 (57%) developed abnormal x-ray findings, 74% of those within the first day. Hypoxia on room air and Po2/Fio2 ratio predicted severity of outcome as assessed by the duration of hospitalization and the need for intensive care support. This community release of chlorine gas caused widespread exposure and resulted in significant acute health effects and substantial health care requirements. Pulse oximetry and arterial blood gas analysis provided early indications of outcome severity. PMID:19041527

  2. Modification of the TASMIP x-ray spectral model for the simulation of microfocus x-ray sources

    SciTech Connect

    Sisniega, A.; Vaquero, J. J.; Desco, M.

    2014-01-15

    Purpose: The availability of accurate and simple models for the estimation of x-ray spectra is of great importance for system simulation, optimization, or inclusion of photon energy information into data processing. There is a variety of publicly available tools for estimation of x-ray spectra in radiology and mammography. However, most of these models cannot be used directly for modeling microfocus x-ray sources due to differences in inherent filtration, energy range and/or anode material. For this reason the authors propose in this work a new model for the simulation of microfocus spectra based on existing models for mammography and radiology, modified to compensate for the effects of inherent filtration and energy range. Methods: The authors used the radiology and mammography versions of an existing empirical model [tungsten anode spectral model interpolating polynomials (TASMIP)] as the basis of the microfocus model. First, the authors estimated the inherent filtration included in the radiology model by comparing the shape of the spectra with spectra from the mammography model. Afterwards, the authors built a unified spectra dataset by combining both models and, finally, they estimated the parameters of the new version of TASMIP for microfocus sources by calibrating against experimental exposure data from a microfocus x-ray source. The model was validated by comparing estimated and experimental exposure and attenuation data for different attenuating materials and x-ray beam peak energy values, using two different x-ray tubes. Results: Inherent filtration for the radiology spectra from TASMIP was found to be equivalent to 1.68 mm Al, as compared to spectra obtained from the mammography model. To match the experimentally measured exposure data the combined dataset required to apply a negative filtration of about 0.21 mm Al and an anode roughness of 0.003 mm W. The validation of the model against real acquired data showed errors in exposure and attenuation in

  3. Modification of the TASMIP x-ray spectral model for the simulation of microfocus x-ray sources

    SciTech Connect

    Sisniega, A.; Vaquero, J. J.; Desco, M.

    2014-01-15

    Purpose: The availability of accurate and simple models for the estimation of x-ray spectra is of great importance for system simulation, optimization, or inclusion of photon energy information into data processing. There is a variety of publicly available tools for estimation of x-ray spectra in radiology and mammography. However, most of these models cannot be used directly for modeling microfocus x-ray sources due to differences in inherent filtration, energy range and/or anode material. For this reason the authors propose in this work a new model for the simulation of microfocus spectra based on existing models for mammography and radiology, modified to compensate for the effects of inherent filtration and energy range. Methods: The authors used the radiology and mammography versions of an existing empirical model [tungsten anode spectral model interpolating polynomials (TASMIP)] as the basis of the microfocus model. First, the authors estimated the inherent filtration included in the radiology model by comparing the shape of the spectra with spectra from the mammography model. Afterwards, the authors built a unified spectra dataset by combining both models and, finally, they estimated the parameters of the new version of TASMIP for microfocus sources by calibrating against experimental exposure data from a microfocus x-ray source. The model was validated by comparing estimated and experimental exposure and attenuation data for different attenuating materials and x-ray beam peak energy values, using two different x-ray tubes. Results: Inherent filtration for the radiology spectra from TASMIP was found to be equivalent to 1.68 mm Al, as compared to spectra obtained from the mammography model. To match the experimentally measured exposure data the combined dataset required to apply a negative filtration of about 0.21 mm Al and an anode roughness of 0.003 mm W. The validation of the model against real acquired data showed errors in exposure and attenuation in

  4. Cancer among medical diagnostic x-ray workers in China

    SciTech Connect

    Wang, J.X.; Boice, J.D. Jr.; Li, B.X.; Zhang, J.Y.; Fraumeni, J.F. Jr.

    1988-05-04

    Cancer incidence among 27,011 diagnostic x-ray workers was compared to that of 25,782 other medical specialists employed between 1950 and 1980 in China. X-ray workers had a 50% higher risk of developing cancer than the other specialists (relative risk (RR) = 1.5; 95% CI = 1.3-1.7). Leukemia was strongly linked to radiation work (RR = 3.5, n = 30). Cancers of the breast (RR = 1.4, n = 11), thyroid (RR = 2.1, n = 7), and skin (RR = 1.5, n = 6) were increased among x-ray workers employed for 10 or more years. High risks of cancers of the esophagus (RR = 3.5, n = 15) and liver (RR = 2.4, n = 48) were not consistent with a radiation effect since risk did not vary by duration of employment. This finding suggested that some differences might exist between groups of hospital workers in social class, alcohol intake, dietary habits, and other risk factors. No excess lung cancer (RR = 0.9, n = 22) or multiple myeloma (n = 0) was observed. Significant excesses of leukemia and cancers of the breast and thyroid occurred among x-ray workers first employed prior to 1960 when radiation exposures in China were high. In fact, it was not uncommon for employees to be given time off from x-ray work because their wbc count was severely depressed. These data indicated that repeated exposure to x-rays over many years can increase the risk of leukemia and several other tumors but apparently not that of lung cancer.

  5. The anomalous X-ray pulsars

    NASA Astrophysics Data System (ADS)

    Chen, Rui; Li, Xiangdong

    2002-03-01

    In the last few years it has been recognized that a group of X-ray pulsars have peculiar properties which set them apart from the majority of accreting pulars in X-ray binaries. They are called the Anomalous X-ray Pulsars (AXP). These objects are characterized by very soft X-ray spectra with low and steady X-ray fluxes, narrow-distributed spin periods, steady spin-down, no optical/infrared counterparts. Some of them may associate with supernova remnants. The nature of AXP remains mysterious. It has been suggested that AXP are accreting neutron stars, or solitary "magnetars", neutron stars with super strong magnetic fields (≍1010-1011T). In this paper we review the recent progress in the studies of AXP, and discuss the possible implications from comparison of AXP with other neutron stars, such as radio pulsars, radio quiet X-ray pulsar candidates and soft γ-ray repeaters.

  6. Stimulated Electronic X-Ray Raman Scattering

    NASA Astrophysics Data System (ADS)

    Weninger, Clemens; Purvis, Michael; Ryan, Duncan; London, Richard A.; Bozek, John D.; Bostedt, Christoph; Graf, Alexander; Brown, Gregory; Rocca, Jorge J.; Rohringer, Nina

    2013-12-01

    We demonstrate strong stimulated inelastic x-ray scattering by resonantly exciting a dense gas target of neon with femtosecond, high-intensity x-ray pulses from an x-ray free-electron laser (XFEL). A small number of lower energy XFEL seed photons drive an avalanche of stimulated resonant inelastic x-ray scattering processes that amplify the Raman scattering signal by several orders of magnitude until it reaches saturation. Despite the large overall spectral width, the internal spiky structure of the XFEL spectrum determines the energy resolution of the scattering process in a statistical sense. This is demonstrated by observing a stochastic line shift of the inelastically scattered x-ray radiation. In conjunction with statistical methods, XFELs can be used for stimulated resonant inelastic x-ray scattering, with spectral resolution smaller than the natural width of the core-excited, intermediate state.

  7. X-Ray Observations of Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    Guerrero, M. A.; Chu, Y.-H.; Gruendl, R. A.

    2004-07-01

    Planetary nebulae (PNe) are an exciting addition to the zoo of X-ray sources. Recent Chandra and XMM-Newton observations have detected diffuse X-ray emission from shocked fast winds in PN interiors as well as bow-shocks of fast collimated outflows impinging on the nebular envelope. Point X-ray sources associated with PN central stars are also detected, with the soft X-ray (<0.5 keV) emission originating from the photospheres of stars hotter than ˜100,000 K, and the hard X-ray (≫0.5 keV) emission from instability shocks in the fast stellar wind itself or from a low-mass companion's coronal activity. X-ray observations of PNe offer a unique opportunity to directly examine the dynamic effects of fast stellar winds and collimated outflows, and help us understand the formation and evolution of PNe.

  8. Stimulated electronic x-ray Raman scattering.

    PubMed

    Weninger, Clemens; Purvis, Michael; Ryan, Duncan; London, Richard A; Bozek, John D; Bostedt, Christoph; Graf, Alexander; Brown, Gregory; Rocca, Jorge J; Rohringer, Nina

    2013-12-06

    We demonstrate strong stimulated inelastic x-ray scattering by resonantly exciting a dense gas target of neon with femtosecond, high-intensity x-ray pulses from an x-ray free-electron laser (XFEL). A small number of lower energy XFEL seed photons drive an avalanche of stimulated resonant inelastic x-ray scattering processes that amplify the Raman scattering signal by several orders of magnitude until it reaches saturation. Despite the large overall spectral width, the internal spiky structure of the XFEL spectrum determines the energy resolution of the scattering process in a statistical sense. This is demonstrated by observing a stochastic line shift of the inelastically scattered x-ray radiation. In conjunction with statistical methods, XFELs can be used for stimulated resonant inelastic x-ray scattering, with spectral resolution smaller than the natural width of the core-excited, intermediate state.

  9. X-ray effects in charge-ordered manganites: A magnetic mechanism of persistent photoconductivity

    SciTech Connect

    Keimer, B.; Casa, D.; Kiryukhin, V.; Saleh, O.A.; Hill, J.P.; Tomioka, Y.; Tokura, Y. |

    1998-12-31

    Charge-ordered manganites of composite Pr{sub 1{minus}x}(Ca{sub 1{minus}y}Sr{sub y}){sub x}MnO{sub 3} exhibit persistent photoconductivity when illuminated by x-rays. The authors review transport and x-ray diffraction data as functions of x-ray exposure, magnetic field, and temperature which shed light on the origin of this unusual behavior. The experimental evidence suggests that the mechanism primarily involves a ferromagnetic polarization of local spins by hot electrons generated by the x-rays.

  10. Hard X-ray irradiation of cosmic silicate analogs: structural evolution and astrophysical implications

    NASA Astrophysics Data System (ADS)

    Gavilan, L.; Jäger, C.; Simionovici, A.; Lemaire, J. L.; Sabri, T.; Foy, E.; Yagoubi, S.; Henning, T.; Salomon, D.; Martinez-Criado, G.

    2016-03-01

    Context. Protoplanetary disks, interstellar clouds, and active galactic nuclei contain X-ray-dominated regions. X-rays interact with the dust and gas present in such environments. While a few laboratory X-ray irradiation experiments have been performed on ices, X-ray irradiation experiments on bare cosmic dust analogs have been scarce up to now. Aims: Our goal is to study the effects of hard X-rays on cosmic dust analogs via in situ X-ray diffraction. By using a hard X-ray synchrotron nanobeam, we seek to simulate cumulative X-ray exposure on dust grains during their lifetime in these astrophysical environments and provide an upper limit on the effect of hard X-rays on dust grain structure. Methods: We prepared enstatite (MgSiO3) nanograins, which are analogs to cosmic silicates, via the melting-quenching technique. These amorphous grains were then annealed to obtain polycrystalline grains. These were characterized via scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) before irradiation. Powder samples were prepared in X-ray transparent substrates and were irradiated with hard X-rays nanobeams (29.4 keV) provided by beamline ID16B of the European Synchrotron Radiation Facility (Grenoble). X-ray diffraction images were recorded in transmission mode, and the ensuing diffractograms were analyzed as a function of the total X-ray exposure time. Results: We detected the amorphization of polycrystalline silicates embedded in an organic matrix after an accumulated X-ray exposure of 6.4 × 1027 eV cm-2. Pure crystalline silicate grains (without resin) do not exhibit amorphization. None of the amorphous silicate samples (pure and embedded in resin) underwent crystallization. We analyze the evolution of the polycrystalline sample embedded in an organic matrix as a function of X-ray exposure. Conclusions: Loss of diffraction peak intensity, peak broadening, and the disappearance of discrete spots and arcs reveal the amorphization

  11. The trickle before the torrent-diffraction data from X-ray lasers.

    PubMed

    Maia, Filipe R N C; Hajdu, Janos

    2016-08-01

    Today Scientific Data launched a collection of publications describing data from X-ray free-electron lasers under the theme 'Structural Biology Applications of X-ray Lasers'. The papers cover data on nanocrystals, single virus particles, isolated cell organelles, and living cells. All data are deposited with the Coherent X-ray Imaging Data Bank (CXIDB) and available to the scientific community to develop ideas, tools and procedures to meet challenges with the expected torrents of data from new X-ray lasers, capable of producing billion exposures per day.

  12. X-ray Induced Effects on Photocurrents in Amorphous Se Films

    NASA Astrophysics Data System (ADS)

    Shimakawa, Koichi; Fukami, Kenji; Kishi, Hiroki; Belev, George; Kasap, Safa

    2007-03-01

    Amorphous selenium (a-Se) is one of the X-ray photoconductors that is available for use in recently developed direct conversion flat panel X-ray image detectors for medical imaging. To obtain a better understanding of trapping and recombination effects in a-Se, we have studied light and X-ray induced photocurrents in a-Se films. The residual photocurrent, after X-ray exposure, decreases in sandwich cells whereas it increases in coplanar cells. These effects are recovered over a time scale of hours. We show that the results can be interpreted by using valence alternation pair (VAP) type charged defects.

  13. The trickle before the torrent—diffraction data from X-ray lasers

    PubMed Central

    Maia, Filipe R.N.C.; Hajdu, Janos

    2016-01-01

    Today Scientific Data launched a collection of publications describing data from X-ray free-electron lasers under the theme ‘Structural Biology Applications of X-ray Lasers’. The papers cover data on nanocrystals, single virus particles, isolated cell organelles, and living cells. All data are deposited with the Coherent X-ray Imaging Data Bank (CXIDB) and available to the scientific community to develop ideas, tools and procedures to meet challenges with the expected torrents of data from new X-ray lasers, capable of producing billion exposures per day. PMID:27479637

  14. X-ray micrography and imaging of Escherichia coli cell shape using laser plasma pulsed point x-ray sources.

    PubMed

    Rajyaguru, J M; Kado, M; Richardson, M C; Muszynski, M J

    1997-04-01

    High-resolution x-ray microscopy is a relatively new technique and is performed mostly at a few large synchrotron x-ray sources that use exposure times of seconds. We utilized a bench-top source of single-shot laser (ns) plasma to generate x-rays similar to synchrotron facilities. A 5 microlitres suspension of Escherichia coli ATCC 25922 in 0.9% phosphate buffered saline was placed on polymethylmethyacrylate coated photoresist, covered with a thin (100 nm) SiN window and positioned in a vacuum chamber close to the x-ray source. The emission spectrum was tuned for optimal absorption by carbon-rich material. Atomic force microscope scans provided a surface and topographical image of differential x-ray absorption corresponding to specimen properties. By using this technique we observed a distinct layer around whole cells, possibly representing the Gram-negative envelope, darker stained areas inside the cell corresponding to chromosomal DNA as seen by thin section electron microscopy, and dent(s) midway through one cell, and 1/3- and 2/3-lengths in another cell, possibly representing one or more division septa. This quick and high resolution with depth-of-field microscopy technique is unmatched to image live hydrated ultrastructure, and has much potential for application in the study of fragile biological specimens.

  15. The Overutilization of X-rays

    PubMed Central

    Lyon, W. K.

    1981-01-01

    Within 20 years of Roentgen's discovery of X-rays in 1895, it became apparent that large doses of radiation damaged human tissue.1 Yet the medical profession continues to contribute to the overutilization of X-rays, occasionally spending health care dollars to subject our patients to a health risk. This paper discusses the evidence to support the claim that X-rays are overutilized, and offers recommendations to rectify the situation. PMID:21289771

  16. X-ray transmissive debris shield

    DOEpatents

    Spielman, Rick B.

    1994-01-01

    A composite window structure is described for transmitting x-ray radiation and for shielding radiation generated debris. In particular, separate layers of different x-ray transmissive materials are laminated together to form a high strength, x-ray transmissive debris shield which is particularly suited for use in high energy fluences. In one embodiment, the composite window comprises alternating layers of beryllium and a thermoset polymer.

  17. Topological X-Rays and MRIs

    ERIC Educational Resources Information Center

    Lynch, Mark

    2002-01-01

    Let K be a compact subset of the interior of the unit disk D in the plane and suppose one can't see through the boundary of D and identify K. However, assume that one can take "topological X-rays" of D which measure the "density" of K along the lines of the X-rays. By taking these X-rays from all directions, a "topological MRI" is generated for…

  18. X-ray data booklet. Revision

    SciTech Connect

    Vaughan, D.

    1986-04-01

    A compilation of data is presented. Included are properties of the elements, electron binding energies, characteristic x-ray energies, fluorescence yields for K and L shells, Auger energies, energy levels for hydrogen-, helium-, and neonlike ions, scattering factors and mass absorption coefficients, and transmission bands of selected filters. Also included are selected reprints on scattering processes, x-ray sources, optics, x-ray detectors, and synchrotron radiation facilities. (WRF)

  19. UV observations of x ray binaries

    NASA Technical Reports Server (NTRS)

    Raymond, John C.

    1990-01-01

    IUE (International Ultraviolet Explorer) has observed both high and low mass x ray binaries throughout its life. The UV spectra of high mass systems reveal the nature of the massive companion star and the effects of the x ray illumination of the stellar wind. In loss mass systems, the x ray illuminated disk or companion star dominates the UV light. System parameters and the characteristics of the accretion disk can be inferred.

  20. Topological X-Rays and MRIs

    ERIC Educational Resources Information Center

    Lynch, Mark

    2002-01-01

    Let K be a compact subset of the interior of the unit disk D in the plane and suppose one can't see through the boundary of D and identify K. However, assume that one can take "topological X-rays" of D which measure the "density" of K along the lines of the X-rays. By taking these X-rays from all directions, a "topological MRI" is generated for…