WorldWideScience

Sample records for ultrasound exposure time

  1. Lysis of Chlamydomonas reinhardtii by high-intensity focused ultrasound as a function of exposure time.

    Science.gov (United States)

    Bigelow, Timothy A; Xu, Jin; Stessman, Dan J; Yao, Linxing; Spalding, Martin H; Wang, Tong

    2014-05-01

    Efficient lysis of microalgae for lipid extraction is an important concern when processing biofuels. Historically, ultrasound frequencies in the range of 10-40 kHz have been utilized for this task. However, greater efficiencies might be achievable if higher frequencies could be used. In our study, we evaluated the potential of using 1.1 MHz ultrasound to lyse microalgae for biofuel production while using Chlamydomonas reinhardtii as a model organism. The ultrasound was generated using a spherically focused transducer with a focal length of 6.34 cm and an active diameter of 6.36 cm driven by 20 cycle sine-wave tone bursts at a pulse repetition frequency of 2 kHz (3.6% duty cycle). The time-average acoustic power output was 26.2 W while the spatial-peak-pulse-average intensity (ISPPA) for each tone burst was 41 kW/cm(2). The peak compressional and rarefactional pressures at the focus were 102 and 17 MPa, respectively. The exposure time was varied for the different cases in the experiments from 5s to 9 min and cell lysis was assessed by quantifying the percentage of protein and chlorophyll release into the supernate as well as the lipid extractability. Free radical generation and lipid oxidation for the different ultrasound exposures were also determined. We found that there was a statistically significant increase in lipid extractability for all of the exposures compared to the control. The longer exposures also completely fragmented the cells releasing almost all of the protein and chlorophyll into the supernate. The cavitation activity did not significantly increase lipid oxidation while there was a minor trend of increased free radical production with increased ultrasound exposure. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Patient-exposure data for doppler ultrasound

    International Nuclear Information System (INIS)

    Stewart, H.F.; Silvis, P.X.; Smith, S.W.

    1986-01-01

    In recent years ultrasound imaging and Doppler blood flow measurements have become important tools for use in diagnostic medicine. Commercial pulse-echo imaging equipment was first introduced into commerce in 1963. The first commercial continuous wave Doppler unit was introduced to the marketplace in 1966. As equipment improved and applications developed, the industry experienced rapid growth in the 1970s. One of the more recent growth areas in the application of diagnostic ultrasound has been the use of pulsed Doppler equipment for cardiac applications. Prior to 1976, some continuous wave Doppler ultrasound was used for cardiovascular diagnosis. However, only a single manufacturer marketed a pulsed Doppler clinical instrument for cardiac or peripheral vascular diagnosis. Currently, many continuous wave and pulsed Doppler instruments are commercially available for both peripheral vascular and cardiac diagnosis. This chapter (1) briefly reviews current safety guidelines, regulations, and recommendations for diagnostic ultrasound; (2) discusses the patient-exposure intensities associated with Doppler ultrasound medical equipment and compare these levels of exposure with intensities from other medical ultrasound devices; and (3) considers some of the current information as it relates to the safety of diagnostic ultrasound

  3. Basic study on apoptosis induction into cancer cells U-937 and EL-4 by ultrasound exposure.

    Science.gov (United States)

    Takeuchi, Shinichi; Udagawa, Yoshiko; Oku, Yumiko; Fujii, Takuma; Nishimura, Hiroyuki; Kawashima, Norimichi

    2006-12-22

    Recently, the low invasive cancer treatments with small aftereffects have been considered. We are studying on the suppression methods of cancer cell proliferation with ultrasound. Cancer cells of mouse T lymphoma (EL-4) have been used in our study. The human histitocytic lymphoma cells (U-937) was used in this time. The cancer cells were cultured in a culture medium of RPMI1640. The standing wave acoustic field was formed in a water tank of our ultrasound exposure system by a vibrating plate driven with a Langevine type transducer. The U-937 and EL-4 were exposed to ultrasound in the acoustic field with spatial average acoustic intensity of 350 mW/cm(2) at 150 kHz. The viable rate of EL-4 decreased with the lapse of culture time after ultrasound exposure. U-937 did not show the remarkable decrease tendency. The proliferation of U-937 which exposed to ultrasound with 700 mW/cm(2) was suppressed. It can be thought that apoptosis was induced in the cancer cells in this condition. We observed the morphological change on the U-937 exposed to ultrasound with this condition. The morphological changes by apoptosis like the shrink of cells, formation of apoptotic bodies etc. can be observed with an optical microscope and a phase contrast microscope.

  4. Time-reversal acoustics and ultrasound-assisted convection-enhanced drug delivery to the brain.

    Science.gov (United States)

    Olbricht, William; Sistla, Manjari; Ghandi, Gaurav; Lewis, George; Sarvazyan, Armen

    2013-08-01

    Time-reversal acoustics is an effective way of focusing ultrasound deep inside heterogeneous media such as biological tissues. Convection-enhanced delivery is a method of delivering drugs into the brain by infusing them directly into the brain interstitium. These two technologies are combined in a focusing system that uses a "smart needle" to simultaneously infuse fluid into the brain and provide the necessary feedback for focusing ultrasound using time-reversal acoustics. The effects of time-reversal acoustics-focused ultrasound on the spatial distribution of infused low- and high-molecular weight tracer molecules are examined in live, anesthetized rats. Results show that exposing the rat brain to focused ultrasound significantly increases the penetration of infused compounds into the brain. The addition of stabilized microbubbles enhances the effect of ultrasound exposure.

  5. Real-time image fusion involving diagnostic ultrasound

    DEFF Research Database (Denmark)

    Ewertsen, Caroline; Săftoiu, Adrian; Gruionu, Lucian G

    2013-01-01

    The aim of our article is to give an overview of the current and future possibilities of real-time image fusion involving ultrasound. We present a review of the existing English-language peer-reviewed literature assessing this technique, which covers technical solutions (for ultrasound...

  6. Wireless communication of real-time ultrasound data and control

    Science.gov (United States)

    Tobias, Richard J.

    2015-03-01

    The Internet of Things (IoT) is expected to grow to 26 billion connected devices by 2020, plus the PC, smart phone, and tablet segment that includes mobile Health (mHealth) connected devices is projected to account for another 7.3 billion units by 2020. This paper explores some of the real-time constraints on the data-flow and control of a wireless connected ultrasound machine. The paper will define an ultrasound server and the capabilities necessary for real-time use of the device. The concept of an ultrasound server wirelessly (or over any network) connected to multiple lightweight clients on devices like an iPad, iPhone, or Android-based tablet, smartphone and other network-attached displays (i.e., Google Glass) is explored. Latency in the ultrasound data stream is one of the key areas to measure and to focus on keeping as small as possible (20 frames-per-second on a properly configured wireless network. The ultrasound server needs to be designed to accept multiple ultrasound data clients and multiple control clients. A description of the server and some of its key features will be described.

  7. Gamma radiographic exposure time indicator

    International Nuclear Information System (INIS)

    Risbud, V.H.; Thiagarajan, A.; Gangadharan, P.

    1979-01-01

    In industrial radiography, with the proper selection of source and film, the radiographic quality depends very much on the exposure time, which in turn depends upon the source strength and the source to film distance. Conventional methods to arrive at correct exposure time involve time consuming calculations and in these methods the knowledge of the above mentioned parameters is imperative. An instrument to determine the required exposure time has been developed which indicates exposure times in about 30 secs. This covers two commonly used gamma radiography sources, viz., 192 Ir and 60 Co and six commonly used radiography films of different speeds. Knowledge of source strength and source to film distance is not required with the use of this instrument. With a knowledge of the total exposure required by the film to give the required sensitivity and by the measurement of radiation level at the film location, the correct exposure time is determined. The radiation level is measured by placing a GM counter behind the radiographic specimen at the film location. To match the responses of the film and the GM counter, the counter is incorporated in a suitably designed probe. In this instruments, an integrator to integrate the GM-pulses and a constant current integrator (timer) are started simultaneously. The voltage at the GM-pulse integrator is compared with a preselected voltage, (selected on the basis of film type, source, source strength and order of object thickness) by a comparator. The comparator is so adjusted that when the GM-pulse integrator voltage exceeds the preselected voltage, it switches its state and stops the integration of constant current. The constant current integrator output which is proportional to the time taken for the GM-pulse integrator to reach the preselected voltage, is read on a meter graduated in terms of exposure time. The instrument can measure exposure times from 5 minutes to 10 hours read in two ranges, the range-changing being automatic

  8. Lumbar ultrasound: useful gadget or time-consuming gimmick?

    Science.gov (United States)

    Gambling, D R

    2011-10-01

    Despite widespread enthusiasm for using lumbar ultrasound in obstetrics, there are some who believe it is expensive and time-consuming, with undetermined risks and uncertain benefits. For decades, anesthesiologists have striven to perfect the identification and cannulation of the epidural space using skills learned during training and early clinical practice. These skills include knowledge of the relevant anatomy and detection of subtle tactile clues that aid successful placement of an epidural catheter. Indeed, obstetric anesthesiologists have managed to do this with great success without using imaging techniques. There is a long learning curve associated with lumbar ultrasound and it is unclear from the literature if the success rates associated with its use are superior to clinical skill alone. Is it only a matter of time before regulators insist that lumbar ultrasound is used before inserting an epidural? Indeed, this has already happened for central vein catheters. The United States spent $2.2 trillion on health care in 2007, nearly twice the average of other developed nations. If rapid health cost growth persists, one out of every four dollars in the US national economy will be tied up in the health system by 2025. Do obstetric anesthesiologists want to add to these costs by using unnecessary and expensive equipment? Although many feel that diagnostic ultrasound in obstetrics is safe, some argue that we have yet to perform an appropriate risk analysis for lumbar ultrasound during pregnancy. The issue of ultrasound bio-safety needs to be considered before we all jump on the ultrasound bandwagon. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Real-Time Laser Ultrasound Tomography for Profilometry of Solids

    Science.gov (United States)

    Zarubin, V. P.; Bychkov, A. S.; Karabutov, A. A.; Simonova, V. A.; Kudinov, I. A.; Cherepetskaya, E. B.

    2018-01-01

    We studied the possibility of applying laser ultrasound tomography for profilometry of solids. The proposed approach provides high spatial resolution and efficiency, as well as profilometry of contaminated objects or objects submerged in liquids. The algorithms for the construction of tomograms and recognition of the profiles of studied objects using the parallel programming technology NDIVIA CUDA are proposed. A prototype of the real-time laser ultrasound profilometer was used to obtain the profiles of solid surfaces of revolution. The proposed method allows the real-time determination of the surface position for cylindrical objects with an approximation accuracy of up to 16 μm.

  10. Real-Time Implementation of Medical Ultrasound Strain Imaging System

    International Nuclear Information System (INIS)

    Jeong, Mok Kun; Kwon, Sung Jae; Bae, Moo Ho

    2008-01-01

    Strain imaging in a medical ultrasound imaging system can differentiate the cancer or tumor in a lesion that is stiffer than the surrounding tissue. In this paper, a strain imaging technique using quasistatic compression is implemented that estimates the displacement between pre- and postcompression ultrasound echoes and obtains strain by differentiating it in the spatial direction. Displacements are computed from the phase difference of complex baseband signals obtained using their autocorrelation, and errors associated with converting the phase difference into time or distance are compensated for by taking into the center frequency variation. Also, to reduce the effect of operator's hand motion, the displacements of all scanlines are normalized with the result that satisfactory strain image quality has been obtained. These techniques have been incorporated into implementing a medical ultrasound strain imaging system that operates in real time.

  11. In Vivo Real Time Volumetric Synthetic Aperture Ultrasound Imaging

    DEFF Research Database (Denmark)

    Bouzari, Hamed; Rasmussen, Morten Fischer; Brandt, Andreas Hjelm

    2015-01-01

    Synthetic aperture (SA) imaging can be used to achieve real-time volumetric ultrasound imaging using 2-D array transducers. The sensitivity of SA imaging is improved by maximizing the acoustic output, but one must consider the limitations of an ultrasound system, both technical and biological....... This paper investigates the in vivo applicability and sensitivity of volumetric SA imaging. Utilizing the transmit events to generate a set of virtual point sources, a frame rate of 25 Hz for a 90° x 90° field-of-view was achieved. Data were obtained using a 3.5 MHz 32 x 32 elements 2-D phased array...... transducer connected to the experimental scanner (SARUS). Proper scaling is applied to the excitation signal such that intensity levels are in compliance with the U.S. Food and Drug Administration regulations for in vivo ultrasound imaging. The measured Mechanical Index and spatial-peak- temporal...

  12. Ultrasound-Assisted Extraction: Effect of Extraction Time and Solvent ...

    African Journals Online (AJOL)

    Purpose: To investigate the influence of extraction conditions assisted by ultrasound on the quality of extracts obtained from Mesembryanthemum edule shoots. Methods: The extraction procedure was carried out in an ultrasonic bath. The effect of two solvents (methanol and ethanol) and two extraction times (5 and 10 min) ...

  13. Ultrasound

    Science.gov (United States)

    Ultrasound is a useful procedure for monitoring the baby's development in the uterus. Ultrasound uses inaudible sound waves to produce a two-dimensional image of the baby while inside the mother's ...

  14. Sirenomelia apus after trimethoprim exposure: first-trimester ultrasound diagnosis-a case report.

    Science.gov (United States)

    Dosedla, Erik; Kalafusová, Michaela; Calda, Pavel

    2012-01-01

    We report the early prenatal ultrasound diagnosis of sirenomelia apus at 12+4 weeks in a patient with trimethoprim exposure in the vulnerable period. First-trimester scan revealed a malformed fetus with one femur, one small tibia, no feet, intraabdominal unilocular cystic structure, and two-vessel umbilical cord with allantoic cyst. Ultrasound visualization with two/three/four-dimensions was helpful in the process of parental counseling. Copyright © 2012 Wiley Periodicals, Inc.

  15. Model-based ultrasound temperature visualization during and following HIFU exposure.

    Science.gov (United States)

    Ye, Guoliang; Smith, Penny Probert; Noble, J Alison

    2010-02-01

    This paper describes the application of signal processing techniques to improve the robustness of ultrasound feedback for displaying changes in temperature distribution in treatment using high-intensity focused ultrasound (HIFU), especially at the low signal-to-noise ratios that might be expected in in vivo abdominal treatment. Temperature estimation is based on the local displacements in ultrasound images taken during HIFU treatment, and a method to improve robustness to outliers is introduced. The main contribution of the paper is in the application of a Kalman filter, a statistical signal processing technique, which uses a simple analytical temperature model of heat dispersion to improve the temperature estimation from the ultrasound measurements during and after HIFU exposure. To reduce the sensitivity of the method to previous assumptions on the material homogeneity and signal-to-noise ratio, an adaptive form is introduced. The method is illustrated using data from HIFU exposure of ex vivo bovine liver. A particular advantage of the stability it introduces is that the temperature can be visualized not only in the intervals between HIFU exposure but also, for some configurations, during the exposure itself. 2010 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  16. Lesions in Porcine Liver Tissues Created by Continuous High Intensity Ultrasound Exposures in Vitro

    International Nuclear Information System (INIS)

    Zhang Zhe; Chen Tao; Zhang Dong

    2013-01-01

    Lesions in porcine liver tissues created by continuous high intensity focused ultrasound (HIFU) exposures in vitro are theoretically and experimentally investigated, with the transmitter moving along a linear path at a fixed speed. Numerical simulations of the lesion formation are performed based on the Khokhlov—Zabolotskaya—Kuznetov equation and the bio-heat equation. In order to verify the theoretical predictions, experiments are performed in the one-dimensional scanning mode to measure the cross-sectional area of lesions created in the in vitro porcine liver exposed to 1.01-MHz HIFU pulses with the acoustic power of 70 W. The results indicate that, compared to the traditional discrete treatment protocol, the application of a continuous scanning model can create more uniform lesions in tissues and significantly reduces the total treatment time from 47s to 30s

  17. Accounting for Unobservable Exposure Time Bias Wh...

    Data.gov (United States)

    U.S. Department of Health & Human Services — Accounting for Unobservable Exposure Time Bias When Using Medicare Prescription Drug Data Unobservable exposure time is common among Medicare Part D beneficiaries,...

  18. PMO Delivery System Using Bubble Liposomes and Ultrasound Exposure for Duchenne Muscular Dystrophy Treatment.

    Science.gov (United States)

    Negishi, Yoichi; Ishii, Yuko; Nirasawa, Kei; Sasaki, Eri; Endo-Takahashi, Yoko; Suzuki, Ryo; Maruyama, Kazuo

    2018-01-01

    Duchenne muscular dystrophy (DMD) is a genetic disorder characterized by progressive muscle degeneration, caused by nonsense or frameshift mutations in the dystrophin (DMD) gene. Antisense oligonucleotides can be used to induce specific exon skipping; recently, a phosphorodiamidate morpholino oligomer (PMO) has been approved for clinical use in DMD. However, an efficient PMO delivery strategy is required to improve the therapeutic efficacy in DMD patients. We previously developed polyethylene glycol (PEG)-modified liposomes containing ultrasound contrast gas, "Bubble liposomes" (BLs), and found that the combination of BLs with ultrasound exposure is a useful gene delivery tool. Here, we describe an efficient PMO delivery strategy using the combination of BLs and ultrasound exposure to treat muscles in a DMD mouse model (mdx). This ultrasound-mediated BL technique can increase the PMO-mediated exon-skipping efficiency, leading to significantly increased dystrophin expression. Thus, the combination of BLs and ultrasound exposure may be a feasible PMO delivery method to improve therapeutic efficacy and reduce the PMO dosage for DMD treatment.

  19. Fast exposure time decision in multi-exposure HDR imaging

    Science.gov (United States)

    Piao, Yongjie; Jin, Guang

    2012-10-01

    Currently available imaging and display system exists the problem of insufficient dynamic range, and the system cannot restore all the information for an high dynamic range (HDR) scene. The number of low dynamic range(LDR) image samples and fastness of exposure time decision impacts the real-time performance of the system dramatically. In order to realize a real-time HDR video acquisition system, this paper proposed a fast and robust method for exposure time selection in under and over exposure area which is based on system response function. The method utilized the monotony of the imaging system. According to this characteristic the exposure time is adjusted to an initial value to make the median value of the image equals to the middle value of the system output range; then adjust the exposure time to make the pixel value on two sides of histogram be the middle value of the system output range. Thus three low dynamic range images are acquired. Experiments show that the proposed method for adjusting the initial exposure time can converge in two iterations which is more fast and stable than average gray control method. As to the exposure time adjusting in under and over exposed area, the proposed method can use the dynamic range of the system more efficiently than fixed exposure time method.

  20. An experimental system for the study of ultrasound exposure of isolated blood vessels

    NARCIS (Netherlands)

    Tokarczyk, Anna; Rivens, Ian; van Bavel, E.; Symonds-Tayler, Richard; ter Haar, Gail

    2013-01-01

    An experimental system designed for the study of the effects of diagnostic or therapeutic ultrasound exposure on isolated blood vessels in the presence or absence of intraluminal contrast agent is described. The system comprised several components. A microscope was used to monitor vessel size (and

  1. Ultrasound

    Science.gov (United States)

    ... completed. Young children may need additional preparation. When scheduling an ultrasound for yourself or your child, ask ... of Privacy Practices Notice of Nondiscrimination Manage Cookies Advertising Mayo Clinic is a not-for-profit organization ...

  2. Ultrasound

    Science.gov (United States)

    ... reflect off body structures. A computer receives the waves and uses them to create a picture. Unlike with an x-ray or CT scan, this test does not use ionizing radiation. The test is done in the ultrasound ...

  3. Computer tomography urography assisted real-time ultrasound-guided percutaneous nephrolithotomy on renal calculus.

    Science.gov (United States)

    Fang, You-Qiang; Wu, Jie-Ying; Li, Teng-Cheng; Zheng, Hao-Feng; Liang, Guan-Can; Chen, Yan-Xiong; Hong, Xiao-Bin; Cai, Wei-Zhong; Zang, Zhi-Jun; Di, Jin-Ming

    2017-06-01

    This study aimed to assess the role of pre-designed route on computer tomography urography (CTU) in the ultrasound-guided percutaneous nephrolithotomy (PCNL) for renal calculus.From August 2013 to May 2016, a total of 100 patients diagnosed with complex renal calculus in our hospital were randomly divided into CTU group and control group (without CTU assistance). CTU was used to design a rational route for puncturing in CTU group. Ultrasound was used in both groups to establish a working trace in the operation areas. Patients' perioperative parameters and postoperative complications were recorded.All operations were successfully performed, without transferring to open surgery. Time of channel establishment in CTU group (6.5 ± 4.3 minutes) was shorter than the control group (10.0 ± 6.7 minutes) (P = .002). In addition, there was shorter operation time, lower rates of blood transfusion, secondary operation, and less establishing channels. The incidence of postoperative complications including residual stones, sepsis, severe hemorrhage, and perirenal hematoma was lower in CTU group than in control group.Pre-designing puncture route on CTU images would improve the puncturing accuracy, lessen establishing channels as well as improve the security in the ultrasound-guided PCNL for complex renal calculus, but at the cost of increased radiation exposure.

  4. Experimental ultrasound system for real-time synthetic imaging

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Holm, Ole; Jensen, Lars Joost

    1999-01-01

    Digital signal processing is being employed more and more in modern ultrasound scanners. This has made it possible to do dynamic receive focusing for each sample and implement other advanced imaging methods. The processing, however, has to be very fast and cost-effective at the same time. Dedicated...... for synthetic aperture imaging, 2D and 3D B-mode and velocity imaging. The system can be used with 128 element transducers and can excite 128 channels and receive and sample data from 64 channels simultaneously at 40 MHz with 12 bits precision. Data can be processed in real time using the system's 80 signal...... chips are used in order to do real time processing. This often makes it difficult to implement radically different imaging strategies on one platform and makes the scanners less accessible for research purposes. Here flexibility is the prime concern, and the storage of data from all transducer elements...

  5. Changes in clot lysis levels of reteplase and streptokinase following continuous wave ultrasound exposure, at ultrasound intensities following attenuation from the skull bone

    Directory of Open Access Journals (Sweden)

    Roijer Anders

    2008-08-01

    Full Text Available Abstract Background Ultrasound (US has been used to enhance thrombolytic therapy in the treatment of stroke. Considerable attenuation of US intensity is however noted if US is applied over the temporal bone. The aim of this study was therefore to explore possible changes in the effect of thrombolytic drugs during low-intensity, high-frequency continuous-wave ultrasound (CW-US exposure. Methods Clots were made from fresh venous blood drawn from healthy volunteers. Each clot was made from 1.4 ml blood and left to coagulate for 1 hour in a plastic test-tube. The thrombolytic drugs used were, 3600 IU streptokinase (SK or 0.25 U reteplase (r-PA, which were mixed in 160 ml 0.9% NaCl solution. Continuous-wave US exposure was applied at a frequency of 1 MHz and intensities ranging from 0.0125 to 1.2 W/cm2. For each thrombolytic drug (n = 2, SK and r-PA and each intensity (n = 9 interventional clots (US-exposed, n = 6 were submerged in thrombolytic solution and exposed to CW-US while control clots (also submerged in thrombolytic solution, n = 6 were left unexposed to US. To evaluate the effect on clot lysis, the haemoglobin (Hb released from each clot was measured every 20 min for 1 hour (20, 40 and 60 min. The Hb content (mg released was estimated by spectrophotometry at 540 nm. The difference in effect on clot lysis was expressed as the difference in the amount of Hb released between pairs of US-exposed clots and control clots. Statistical analysis was performed using Wilcoxon's signed rank test. Results Continuous-wave ultrasound significantly decreased the effects of SK at intensities of 0.9 and 1.2 W/cm2 at all times (P 2 and at 1.2 W/cm2, following 40 min exposure at 0.3, 0.6, 0.9 and at 1.2 W/cm2, and following 60 min of exposure at 0.05 0.3, 0.6, 0.9 and at 1.2 W/cm2 (all P Conclusion Increasing intensities of CW-US exposure resulted in increased clot lysis of r-PA-treated blood clots, but decreased clot lysis of SK-treated clots.

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

    International Nuclear Information System (INIS)

    Brent, R.L.

    1986-01-01

    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

  7. An experimental system for the study of ultrasound exposure of isolated blood vessels

    International Nuclear Information System (INIS)

    Tokarczyk, Anna; Rivens, Ian; Symonds-Tayler, Richard; Ter Haar, Gail; Van Bavel, E

    2013-01-01

    An experimental system designed for the study of the effects of diagnostic or therapeutic ultrasound exposure on isolated blood vessels in the presence or absence of intraluminal contrast agent is described. The system comprised several components. A microscope was used to monitor vessel size (and thus vessel functionality), and potential leakage of intraluminal 70 kDa FITC-dextran fluorescence marker. A vessel chamber allowed the mounting of an isolated vessel whilst maintaining its viability, with pressure regulation for the control of intraluminal pressure and induction of flow for the infusion of contrast microbubbles. A fibre-optic hydrophone sensor mounted on the vessel chamber using a micromanipulator allowed pre-exposure targeting of the vessel to within 150 µm, and monitoring of acoustic cavitation emissions during exposures. Acoustic cavitation was also detected using changes in the ultrasound drive voltage and by detection of audible emissions using a submerged microphone. The suitability of this system for studying effects in the isolated vessel model has been demonstrated using a pilot study of 6 sham exposed and 18 high intensity focused ultrasound exposed vessels, with or without intraluminal contrast agent (SonoVue) within the vessels. (paper)

  8. Severity of ASD symptoms and their correlation with the presence of copy number variations and exposure to first trimester ultrasound.

    Science.gov (United States)

    Webb, Sara Jane; Garrison, Michelle M; Bernier, Raphael; McClintic, Abbi M; King, Bryan H; Mourad, Pierre D

    2017-03-01

    Current research suggests that incidence and heterogeneity of autism spectrum disorder (ASD) symptoms may arise through a variety of exogenous and/or endogenous factors. While subject to routine clinical practice and generally considered safe, there exists speculation, though no human data, that diagnostic ultrasound may also contribute to ASD severity, supported by experimental evidence that exposure to ultrasound early in gestation could perturb brain development and alter behavior. Here we explored a modified triple hit hypothesis [Williams & Casanova, ] to assay for a possible relationship between the severity of ASD symptoms and (1) ultrasound exposure (2) during the first trimester of pregnancy in fetuses with a (3) genetic predisposition to ASD. We did so using retrospective analysis of data from the SSC (Simon's Simplex Collection) autism genetic repository funded by the Simons Foundation Autism Research Initiative. We found that male children with ASD, copy number variations (CNVs), and exposure to first trimester ultrasound had significantly decreased non-verbal IQ and increased repetitive behaviors relative to male children with ASD, with CNVs, and no ultrasound. These data suggest that heterogeneity in ASD symptoms may result, at least in part, from exposure to diagnostic ultrasound during early prenatal development of children with specific genetic vulnerabilities. These results also add weight to on-going concerns expressed by the FDA about non-medical use of diagnostic ultrasound during pregnancy. Autism Res 2017, 10: 472-484. © 2016 International Society for Autism Research, Wiley Periodicals, Inc. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

  9. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... ultrasound images are captured in real-time, they can show the structure and movement of the body's ... Obstetrical Ultrasound page for more information . Ultrasound examinations can help diagnose symptoms experienced by women such as: ...

  10. Endoscopic ultrasound duplex scanning for measurement of portal venous flow. Validation against transit time ultrasound flowmetry in pigs

    DEFF Research Database (Denmark)

    Hansen, E F; Strandberg, C; Bendtsen, F

    1999-01-01

    with that of transit time ultrasound (TTU) in healthy pigs. The ability of EUS to detect changes in the portal venous flow after pharmacologic intervention was also investigated. METHODS: Six anaesthetized pigs were studied. Portal venous flow was measured simultaneously by EUS duplex scanning, using a Pentax FG-32UA...... echoendoscope connected to a Hitachi EUB 515-A ultrasound scanner, and by TTU with a Cardiomed CM 4000 flowmeter probe placed on the portal vein. Terlipressin, 1 mg, and placebo were administered in a blind, randomized, crossover design. Measurements were taken at base line and 30 min after each drug...

  11. Ultrasound breast imaging using frequency domain reverse time migration

    Science.gov (United States)

    Roy, O.; Zuberi, M. A. H.; Pratt, R. G.; Duric, N.

    2016-04-01

    Conventional ultrasonography reconstruction techniques, such as B-mode, are based on a simple wave propagation model derived from a high frequency approximation. Therefore, to minimize model mismatch, the central frequency of the input pulse is typically chosen between 3 and 15 megahertz. Despite the increase in theoretical resolution, operating at higher frequencies comes at the cost of lower signal-to-noise ratio. This ultimately degrades the image contrast and overall quality at higher imaging depths. To address this issue, we investigate a reflection imaging technique, known as reverse time migration, which uses a more accurate propagation model for reconstruction. We present preliminary simulation results as well as physical phantom image reconstructions obtained using data acquired with a breast imaging ultrasound tomography prototype. The original reconstructions are filtered to remove low-wavenumber artifacts that arise due to the inclusion of the direct arrivals. We demonstrate the advantage of using an accurate sound speed model in the reverse time migration process. We also explain how the increase in computational complexity can be mitigated using a frequency domain approach and a parallel computing platform.

  12. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Ultrasound is the preferred imaging modality for the diagnosis and monitoring of pregnant women and their unborn ... sexes without x-ray exposure. Risks For standard diagnostic ultrasound , there are no known harmful effects on ...

  13. Real Time Deconvolution of In-Vivo Ultrasound Images

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt

    2013-01-01

    and two wavelengths. This can be improved by deconvolution, which increase the bandwidth and equalizes the phase to increase resolution under the constraint of the electronic noise in the received signal. A fixed interval Kalman filter based deconvolution routine written in C is employed. It uses a state...... resolution has been determined from the in-vivo liver image using the auto-covariance function. From the envelope of the estimated pulse the axial resolution at Full-Width-Half-Max is 0.581 mm corresponding to 1.13 l at 3 MHz. The algorithm increases the resolution to 0.116 mm or 0.227 l corresponding...... to a factor of 5.1. The basic pulse can be estimated in roughly 0.176 seconds on a single CPU core on an Intel i5 CPU running at 1.8 GHz. An in-vivo image consisting of 100 lines of 1600 samples can be processed in roughly 0.1 seconds making it possible to perform real-time deconvolution on ultrasound data...

  14. Third trimester ultrasound for fetal macrosomia: optimal timing and institutional specific accuracy.

    Science.gov (United States)

    Parikh, Laura I; Iqbal, Sara N; Jelin, Angie C; Overcash, Rachael T; Tefera, Eshetu; Fries, Melissa H

    2017-11-28

    To determine the performance of third trimester ultrasound in women with suspected fetal macrosomia. We performed a retrospective cohort study of fetal ultrasounds from January 2004 to December 2014 with estimated fetal weight (EFW) between 4000 and 5000 g. We determined accuracy of birth weight prediction for ultrasound performed at less than and greater than 38 weeks, accounting for diabetic status and time between ultrasound and delivery. There were 405 ultrasounds evaluated. One hundred and twelve (27.7%) were performed at less than 38 weeks, 293 (72.3%) at greater than 38 weeks, and 91 (22.5%) were performed in diabetics. Sonographic identification of EFW over 4000 g at less than 38 weeks was associated with higher correlation between EFW and birth weight than ultrasound performed after 38 weeks (71.5 versus 259.4 g, p < .024). EFW to birth weight correlation was within 1.7% of birth weight for ultrasound performed less than 38 weeks and within 6.5% of birth weight for ultrasound performed at greater than 38 weeks. Identification of EFW with ultrasound performed less than 38 weeks has greater reliability of predicting fetal macrosomia at birth than measurements performed later in gestation. EFW to birth weight correlation was more accurate than previous reports.

  15. Analysis of contact stiffness in ultrasound atomic force microscopy: three-dimensional time-dependent ultrasound modeling

    International Nuclear Information System (INIS)

    Piras, Daniele; Sadeghian, Hamed

    2017-01-01

    Ultrasound atomic force microscopy (US-AFM) has been used for subsurface imaging of nanostructures. The contact stiffness variations have been suggested as the origin of the image contrast. Therefore, to analyze the image contrast, the local changes in the contact stiffness due to the presence of subsurface features should be calculated. So far, only static simulations have been conducted to analyze the local changes in the contact stiffness and, consequently, the contrast in US-AFM. Such a static approach does not fully represent the real US-AFM experiment, where an ultrasound wave is launched either into the sample or at the tip, which modulates the contact stiffness. This is a time-dependent nonlinear dynamic problem rather than a static and stationary one. This paper presents dynamic 3D ultrasound analysis of contact stiffness in US-AFM (in contrast to static analysis) to realistically predict the changes in contact stiffness and thus the changes in the subsurface image contrast. The modulation frequency also influences the contact stiffness variations and, thus, the image contrast. The three-dimensional time-dependent ultrasound analysis will greatly aid in the contrast optimization of subsurface nano imaging with US-AFM. (paper)

  16. Real-time 3-dimensional contrast-enhanced ultrasound in detecting hemorrhage of blunt renal trauma.

    Science.gov (United States)

    Xu, Rui-Xue; Li, Ye-Kuo; Li, Ting; Wang, Sha-Sha; Yuan, Gui-Zhong; Zhou, Qun-Fang; Zheng, Hai-Rong; Yan, Fei

    2013-10-01

    The objective of this study is to evaluate the diagnostic value of real-time 3-dimensional contrast-enhanced ultrasound in the hemorrhage of blunt renal trauma. Eighteen healthy New Zealand white rabbits were randomly divided into 3 groups. Blunt renal trauma was performed on each group by using minitype striker. Ultrasonography, color Doppler flow imaging, and contrast-enhanced 2-dimensional and real-time 3-dimensional ultrasound were applied before and after the strike. The time to shock and blood pressure were subjected to statistical analysis. Then, a comparative study of ultrasound and pathology was carried out. All the struck kidneys were traumatic. In the ultrasonography, free fluid was found under the renal capsule. In the color Doppler flow imaging, active hemorrhage was not identified. In 2-dimensional contrast-enhanced ultrasound, active hemorrhage of the damaged kidney was characterized. Real-time 3-dimensional contrast-enhanced ultrasound showed a real-time and stereoscopic ongoing bleeding of the injured kidney. The wider the hemorrhage area in 4-dimensional contrast-enhanced ultrasound was, the faster the blood pressure decreased. Real-time 3-dimensional contrast-enhanced ultrasound is a promising noninvasive tool for stereoscopically and vividly detecting ongoing hemorrhage of blunt renal trauma in real time. © 2013.

  17. Improvement of life time of SCC in type 304 stainless steel by ultrasound irradiation

    International Nuclear Information System (INIS)

    Tokiwai, Moriyasu; Kimura, Hideo

    1985-01-01

    It is well known that the susceptibility to stress corrosion cracking (SCC) is controled by compressive stress such as shot-peening treatment. In this study, the effects of ultrasound irradiation to type 304 stainless upon SCC were investigated. The main findings are as follows; (1) Ultrasound irradiation produces the high level compressive stress on the surface of metals. This compressive stress was induced by the cavitation phenomenon. (2) In U-bent specimen, the initial tensile stress was mitigated and converted to compressive stress by ultrasound irradiation. (3) Type 304 stainless steel was subjected to SCC test using sodium thyosulfate solution. It was definitely demonstrated that the ultrasound irradiation was effective for the mitigation of SCC life time. (4) Ultrasound irradiation time was one of the most important factors in irradiation conditions. (author)

  18. Phyocyanin extraction from microalgae Spirulina platensis assisted by ultrasound irradiation: effect of time and temperature

    Directory of Open Access Journals (Sweden)

    Hadiyanto

    2016-08-01

    Full Text Available This research was aimed to extract phycocyanin from microalgae Spirulina platensis using an extraction assisted by ultrasound irradiation. The extraction was conducted by using variable of extraction time, temperature and ultrasound frequency, while ethanol was used as solvent. The results show that the yield of phycocyanin extract was 15.97% at constant frequency of 42 kHz and 11.24% at constant frequency of 28 kHz, while the soxhlet extraction method obtained yield at 11.13%. The ultrasound could reduce the extraction time from 4 hrs (conventional to 20 minutes, while the optimum temperature of extraction was found at 55°C.

  19. Performance Evaluation of a Synthetic Aperture Real-Time Ultrasound System

    DEFF Research Database (Denmark)

    Stuart, Matthias Bo; Tomov, Borislav Gueorguiev; Jensen, Jørgen Arendt

    2011-01-01

    This paper evaluates the signal-to-noise ratio, the time stability, and the phase difference of the sampling in the experimental ultrasound scanner SARUS: A synthetic aperture, real-time ultrasound system. SARUS has 1024 independent transmit and receive channels and is capable of handling 2D probes...... arrays (FPGAs) making it very flexible and allowing implementation of other real-time ultrasound processing methods in the future. For conventional B-mode imaging, a penetration depth around 7 cm for a 7 MHz transducer is obtained (signal-tonoise ratio of 0 dB), which is comparable to commercial...... for 3D ultrasound imaging. It samples at 12 bits per sample and has a sampling rate of 70 MHz with the possibility of decimating the sampling frequency at the input. SARUS is capable of advanced real-time computations such as synthetic aperture imaging. The system is built using fieldprogrammable gate...

  20. Exposure Influences Expressive Timing Judgments in Music

    Science.gov (United States)

    Honing, Henkjan; Ladinig, Olivia

    2009-01-01

    This study is concerned with the question whether, and to what extent, listeners' previous exposure to music in everyday life, and expertise as a result of formal musical training, play a role in making expressive timing judgments in music. This was investigated by using a Web-based listening experiment in which listeners with a wide range of…

  1. Exposure influences expressive timing judgments in music

    NARCIS (Netherlands)

    Honing, H.; Ladinig, O.

    2009-01-01

    This study is concerned with the question whether, and to what extent, listeners' previous exposure to music in everyday life, and expertise as a result of formal musical training, play a role in making expressive timing judgments in music. This was investigated by using a Web-based listening

  2. Local Gene Delivery System by Bubble Liposomes and Ultrasound Exposure into Joint Synovium

    Directory of Open Access Journals (Sweden)

    Yoichi Negishi

    2011-01-01

    Full Text Available Recently, we have developed novel polyethylene glycol modified liposomes (bubble liposomes; BL entrapping an ultrasound (US imaging gas, which can work as a gene delivery tool with US exposure. In this study, we investigated the usefulness of US-mediated gene transfer systems with BL into synoviocytes in vitro and joint synovium in vivo. Highly efficient gene transfer could be achieved in the cultured primary synoviocytes transfected with the combination of BL and US exposure, compared to treatment with plasmid DNA (pDNA alone, pDNA plus BL, or pDNA plus US. When BL was injected into the knee joints of mice, and US exposure was applied transcutaneously to the injection site, highly efficient gene expression could be observed in the knee joint transfected with the combination of BL and US exposure, compared to treatment with pDNA alone, pDNA plus BL, or pDNA plus US. The localized and prolonged gene expression was also shown by an in vivo luciferase imaging system. Thus, this local gene delivery system into joint synovium using the combination of BL and US exposure may be an effective means for gene therapy in joint disorders.

  3. Applicable value of real time interventional ultrasound guidance in family planning reproduction operation

    International Nuclear Information System (INIS)

    Wu Guoping; Zou Dongfang; Sun Jian; Dong Weihua

    2007-01-01

    Objective: To determine the clinical value of real time interventional ultrasound guidance in family planning reproduction operation. Methods: Under the guidance of ultrasound monitoring, 522 cases with high risk and difficult uterine operation were undertaken in our department. Results: The abdominal endoscopic contraceptive uterine operation under real time ultrasound monitoring was carried out for 522 cases in 4 years, with successful rates for high risk pregnancy as 287/289 cases, high risk troublesome withdrawal of contraceptive ring as 129/130 cases and puzzling uterine operation as 103/103 cases. The total successful rate reached 99.42%, without uterine rupture and other complications. Conclusion: The former complex, blind and difficult uterine operations turn to be simple, safe and reliable under the guidance of real time ultrasound. (authors)

  4. Real-time images of tidal recruitment using lung ultrasound.

    Science.gov (United States)

    Tusman, Gerardo; Acosta, Cecilia M; Nicola, Marco; Esperatti, Mariano; Bohm, Stephan H; Suarez-Sipmann, Fernando

    2015-12-01

    Ventilator-induced lung injury is a form of mechanical damage leading to a pulmonary inflammatory response related to the use of mechanical ventilation enhanced by the presence of atelectasis. One proposed mechanism of this injury is the repetitive opening and closing of collapsed alveoli and small airways within these atelectatic areas-a phenomenon called tidal recruitment. The presence of tidal recruitment is difficult to detect, even with high-resolution images of the lungs like CT scan. The purpose of this article is to give evidence of tidal recruitment by lung ultrasound. A standard lung ultrasound inspection detected lung zones of atelectasis in mechanically ventilated patients. With a linear probe placed in the intercostal oblique position. We observed tidal recruitment within atelectasis as an improvement in aeration at the end of inspiration followed by the re-collapse at the end of expiration. This mechanism disappeared after the performance of a lung recruitment maneuver. Lung ultrasound was helpful in detecting the presence of atelectasis and tidal recruitment and in confirming their resolution after a lung recruitment maneuver.

  5. Inverse effects of flowing phase-shift nanodroplets and lipid-shelled microbubbles on subsequent cavitation during focused ultrasound exposures.

    Science.gov (United States)

    Zhang, Siyuan; Cui, Zhiwei; Xu, Tianqi; Liu, Pan; Li, Dapeng; Shang, Shaoqiang; Xu, Ranxiang; Zong, Yujin; Niu, Gang; Wang, Supin; He, Xijing; Wan, Mingxi

    2017-01-01

    This paper compared the effects of flowing phase-shift nanodroplets (NDs) and lipid-shelled microbubbles (MBs) on subsequent cavitation during focused ultrasound (FUS) exposures. The cavitation activity was monitored using a passive cavitation detection method as solutions of either phase-shift NDs or lipid-shelled MBs flowed at varying velocities through a 5-mm diameter wall-less vessel in a transparent tissue-mimicking phantom when exposed to FUS. The intensity of cavitation for the phase-shift NDs showed an upward trend with time and cavitation for the lipid-shelled MBs grew to a maximum at the outset of the FUS exposure followed by a trend of decreases when they were static in the vessel. Meanwhile, the increase of cavitation for the phase-shift NDs and decrease of cavitation for the lipid-shelled MBs had slowed down when they flowed through the vessel. During two discrete identical FUS exposures, while the normalized inertial cavitation dose (ICD) value for the lipid-shelled MB solution was higher than that for the saline in the first exposure (p-value 0.95). Meanwhile, the normalized ICD value for the phase-shift NDs was 0.182 at a flow velocity of 5cm/s and increased to 0.188 at a flow velocity of 15cm/s. As the flow velocity increased to 20cm/s, the normalized ICD was 0.185 and decreased to 0.178 at a flow velocity of 30cm/s. At high acoustic power, the normalized ICD values for both the lipid-shelled MBs and the phase-shift NDs increased with increasing flow velocities from 5 to 30cm/s (r>0.95). The effects of the flowing phase-shift NDs vaporized into gas bubbles as cavitation nuclei on the subsequent cavitation were inverse to those of the flowing lipid-shelled MBs destroyed after focused ultrasound exposures. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Strain measurement of abdominal aortic aneurysm with real-time 3D ultrasound speckle tracking.

    Science.gov (United States)

    Bihari, P; Shelke, A; Nwe, T H; Mularczyk, M; Nelson, K; Schmandra, T; Knez, P; Schmitz-Rixen, T

    2013-04-01

    Abdominal aortic aneurysm rupture is caused by mechanical vascular tissue failure. Although mechanical properties within the aneurysm vary, currently available ultrasound methods assess only one cross-sectional segment of the aorta. This study aims to establish real-time 3-dimensional (3D) speckle tracking ultrasound to explore local displacement and strain parameters of the whole abdominal aortic aneurysm. Validation was performed on a silicone aneurysm model, perfused in a pulsatile artificial circulatory system. Wall motion of the silicone model was measured simultaneously with a commercial real-time 3D speckle tracking ultrasound system and either with laser-scan micrometry or with video photogrammetry. After validation, 3D ultrasound data were collected from abdominal aortic aneurysms of five patients and displacement and strain parameters were analysed. Displacement parameters measured in vitro by 3D ultrasound and laser scan micrometer or video analysis were significantly correlated at pulse pressures between 40 and 80 mmHg. Strong local differences in displacement and strain were identified within the aortic aneurysms of patients. Local wall strain of the whole abdominal aortic aneurysm can be analysed in vivo with real-time 3D ultrasound speckle tracking imaging, offering the prospect of individual non-invasive rupture risk analysis of abdominal aortic aneurysms. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  7. Prostate Ultrasound

    Medline Plus

    Full Text Available ... patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... test result. difficulty urinating. Because ultrasound provides real-time images, it also can be used to guide ...

  8. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... help to distract the child and make the time pass quickly. The ultrasound exam room may have ...

  9. Prostate Ultrasound

    Medline Plus

    Full Text Available ... ultrasound images are captured in real-time, they can show the structure and movement of the body's ... Because ultrasound provides real-time images, it also can be used to guide procedures such as needle ...

  10. A real-time remote video streaming platform for ultrasound imaging.

    Science.gov (United States)

    Ahmadi, Mehdi; Gross, Warren J; Kadoury, Samuel

    2016-08-01

    Ultrasound is a viable imaging technology in remote and resources-limited areas. Ultrasonography is a user-dependent skill which depends on a high degree of training and hands-on experience. However, there is a limited number of skillful sonographers located in remote areas. In this work, we aim to develop a real-time video streaming platform which allows specialist physicians to remotely monitor ultrasound exams. To this end, an ultrasound stream is captured and transmitted through a wireless network into remote computers, smart-phones and tablets. In addition, the system is equipped with a camera to track the position of the ultrasound probe. The main advantage of our work is using an open source platform for video streaming which gives us more control over streaming parameters than the available commercial products. The transmission delays of the system are evaluated for several ultrasound video resolutions and the results show that ultrasound videos close to the high-definition (HD) resolution can be received and displayed on an Android tablet with the delay of 0.5 seconds which is acceptable for accurate real-time diagnosis.

  11. A deconvolution method for deriving the transit time spectrum for ultrasound propagation through cancellous bone replica models.

    Science.gov (United States)

    Langton, Christian M; Wille, Marie-Luise; Flegg, Mark B

    2014-04-01

    The acceptance of broadband ultrasound attenuation for the assessment of osteoporosis suffers from a limited understanding of ultrasound wave propagation through cancellous bone. It has recently been proposed that the ultrasound wave propagation can be described by a concept of parallel sonic rays. This concept approximates the detected transmission signal to be the superposition of all sonic rays that travel directly from transmitting to receiving transducer. The transit time of each ray is defined by the proportion of bone and marrow propagated. An ultrasound transit time spectrum describes the proportion of sonic rays having a particular transit time, effectively describing lateral inhomogeneity of transit times over the surface of the receiving ultrasound transducer. The aim of this study was to provide a proof of concept that a transit time spectrum may be derived from digital deconvolution of input and output ultrasound signals. We have applied the active-set method deconvolution algorithm to determine the ultrasound transit time spectra in the three orthogonal directions of four cancellous bone replica samples and have compared experimental data with the prediction from the computer simulation. The agreement between experimental and predicted ultrasound transit time spectrum analyses derived from Bland-Altman analysis ranged from 92% to 99%, thereby supporting the concept of parallel sonic rays for ultrasound propagation in cancellous bone. In addition to further validation of the parallel sonic ray concept, this technique offers the opportunity to consider quantitative characterisation of the material and structural properties of cancellous bone, not previously available utilising ultrasound.

  12. Real-time three-dimensional ultrasound-assisted axillary plexus block defines soft tissue planes.

    Science.gov (United States)

    Clendenen, Steven R; Riutort, Kevin; Ladlie, Beth L; Robards, Christopher; Franco, Carlo D; Greengrass, Roy A

    2009-04-01

    Two-dimensional (2D) ultrasound is commonly used for regional block of the axillary brachial plexus. In this technical case report, we described a real-time three-dimensional (3D) ultrasound-guided axillary block. The difference between 2D and 3D ultrasound is similar to the difference between plain radiograph and computer tomography. Unlike 2D ultrasound that captures a planar image, 3D ultrasound technology acquires a 3D volume of information that enables multiple planes of view by manipulating the image without movement of the ultrasound probe. Observation of the brachial plexus in cross-section demonstrated distinct linear hyperechoic tissue structures (loose connective tissue) that initially inhibited the flow of the local anesthesia. After completion of the injection, we were able to visualize the influence of arterial pulsation on the spread of the local anesthesia. Possible advantages of this novel technology over current 2D methods are wider image volume and the capability to manipulate the planes of the image without moving the probe.

  13. Ultrasound in gynecological cancer: is it time for re-evaluation of its uses?

    Science.gov (United States)

    Fischerova, Daniela; Cibula, David

    2015-06-01

    Ultrasound is the primary imaging modality in gynecological oncology. Over the last decade, there has been a massive technology development which led to a dramatic improvement in the quality ultrasound imaging. If performed by an experienced sonographer, ultrasound has an invaluable role in the primary diagnosis of gynecological cancer, in the assessment of tumor extent in the pelvis and abdominal cavity, in the evaluation of the treatment response, and in follow-up. Ultrasound is also a valuable procedure for monitoring patients treated with fertility-sparing surgery. Furthermore, it is an ideal technique to guide tru-cut biopsy for the collection of material for histology. Taking into consideration that besides its accuracy, the ultrasound is a commonly available, non-invasive, and inexpensive imaging method that can be carried out without any risk or discomfort to the patient; it is time to reconsider its role in gynecologic oncology and to allocate resources for a specialized education of future experts in ultrasound imaging in gynecology.

  14. Exposure criteria for medical diagnostic ultrasound: 1, Criteria based on thermal mechanisms

    International Nuclear Information System (INIS)

    1992-01-01

    A previous report (NCRP, 1983) contains a comprehensive review of biological effects and mechanisms of action of ultrasound and an analysis of their implications for medical ultrasound. This Report presents background material for a scientifically-based approach to safety assessment of ultrasound. It is intended to help the medical community take advantage of new developments, while maintaining the excellent safety record which now exists for diagnostic ultrasound

  15. Toward a real-time system for temporal enhanced ultrasound-guided prostate biopsy.

    Science.gov (United States)

    Azizi, Shekoofeh; Van Woudenberg, Nathan; Sojoudi, Samira; Li, Ming; Xu, Sheng; Abu Anas, Emran M; Yan, Pingkun; Tahmasebi, Amir; Kwak, Jin Tae; Turkbey, Baris; Choyke, Peter; Pinto, Peter; Wood, Bradford; Mousavi, Parvin; Abolmaesumi, Purang

    2018-03-27

    We have previously proposed temporal enhanced ultrasound (TeUS) as a new paradigm for tissue characterization. TeUS is based on analyzing a sequence of ultrasound data with deep learning and has been demonstrated to be successful for detection of cancer in ultrasound-guided prostate biopsy. Our aim is to enable the dissemination of this technology to the community for large-scale clinical validation. In this paper, we present a unified software framework demonstrating near-real-time analysis of ultrasound data stream using a deep learning solution. The system integrates ultrasound imaging hardware, visualization and a deep learning back-end to build an accessible, flexible and robust platform. A client-server approach is used in order to run computationally expensive algorithms in parallel. We demonstrate the efficacy of the framework using two applications as case studies. First, we show that prostate cancer detection using near-real-time analysis of RF and B-mode TeUS data and deep learning is feasible. Second, we present real-time segmentation of ultrasound prostate data using an integrated deep learning solution. The system is evaluated for cancer detection accuracy on ultrasound data obtained from a large clinical study with 255 biopsy cores from 157 subjects. It is further assessed with an independent dataset with 21 biopsy targets from six subjects. In the first study, we achieve area under the curve, sensitivity, specificity and accuracy of 0.94, 0.77, 0.94 and 0.92, respectively, for the detection of prostate cancer. In the second study, we achieve an AUC of 0.85. Our results suggest that TeUS-guided biopsy can be potentially effective for the detection of prostate cancer.

  16. Spatial and temporal observation of phase-shift nano-emulsions assisted cavitation and ablation during focused ultrasound exposure.

    Science.gov (United States)

    Qiao, Yangzi; Zong, Yujin; Yin, Hui; Chang, Nan; Li, Zhaopeng; Wan, Mingxi

    2014-09-01

    Phase-shift nano-emulsions (PSNEs) with a small initial diameter in nanoscale have the potential to leak out of the blood vessels and to accumulate at the target point of tissue. At desired location, PSNEs can undergo acoustic droplet vaporization (ADV) process, change into gas bubbles and enhance focused ultrasound efficiency. The threshold of droplet vaporization and influence of acoustic parameters have always been research hotspots in order to spatially control the potential of bioeffects and optimize experimental conditions. However, when the pressure is much higher than PSNEs' vaporization threshold, there were little reports on their cavitation and thermal effects. In this study, PSNEs induced cavitation and ablation effects during pulsed high-intensity focused ultrasound (HIFU) exposure were investigated, including the spatial and temporal information and the influence of acoustic parameters. Two kinds of tissue-mimicking phantoms with uniform PSNEs were prepared because of their optical transparency. The Sonoluminescence (SL) method was employed to visualize the cavitation activities. And the ablation process was observed as the heat deposition could produce white lesion. Precisely controlled HIFU cavitation and ablation can be realized at a relatively low input power. But when the input power was high, PSNEs can accelerate cavitation and ablation in pre-focal region. The cavitation happened layer by layer advancing the transducer. While the lesion appeared to be separated into two parts, one in pre-focal region stemmed from one point and grew quickly, the other in focal region grew much more slowly. The influence of duty cycle has also been examined. Longer pulse off time would cause heat transfer to the surrounding media, and generate smaller lesion. On the other hand, this would give outer layer bubbles enough time to dissolve, and inner bubbles can undergo violent collapse and emit bright light. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Real-time ultrasound-guided spinal anaesthesia: a prospective observational study of a new approach.

    LENUS (Irish Health Repository)

    Conroy, P H

    2013-01-01

    Identification of the subarachnoid space has traditionally been achieved by either a blind landmark-guided approach or using prepuncture ultrasound assistance. To assess the feasibility of performing spinal anaesthesia under real-time ultrasound guidance in routine clinical practice we conducted a single center prospective observational study among patients undergoing lower limb orthopaedic surgery. A spinal needle was inserted unassisted within the ultrasound transducer imaging plane using a paramedian approach (i.e., the operator held the transducer in one hand and the spinal needle in the other). The primary outcome measure was the success rate of CSF acquisition under real-time ultrasound guidance with CSF being located in 97 out of 100 consecutive patients within median three needle passes (IQR 1-6). CSF was not acquired in three patients. Subsequent attempts combining landmark palpation and pre-puncture ultrasound scanning resulted in successful spinal anaesthesia in two of these patients with the third patient requiring general anaesthesia. Median time from spinal needle insertion until intrathecal injection completion was 1.2 minutes (IQR 0.83-4.1) demonstrating the feasibility of this technique in routine clinical practice.

  18. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... insertion. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time ...

  19. Prostate Ultrasound

    Medline Plus

    Full Text Available ... Ultrasound provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as ... bowel (rectum) removed during prior surgery are not good candidates for ultrasound of the prostate gland because ...

  20. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... most ultrasound exams, you will be positioned lying face-up on an examination table that can be ... region of the prostate. A biopsy will add time to the procedure. If a Doppler ultrasound study ...

  1. Magnetic resonance imaging, ultrasound and real-time ultrasound elastography of the thigh muscles in congenital muscle dystrophy

    Energy Technology Data Exchange (ETDEWEB)

    Drakonaki, Eleni E. [University of Crete, Radiology Department, Heraklion (Greece); Allen, Gina M. [Green Templeton College, Oxford (United Kingdom)

    2010-04-15

    Congenital muscle dystrophy includes a range of genetic disorders characterized by muscle weakness and contractures. We report the magnetic resonance (MR), ultrasound (US) and real-time sonoelastography (RTE) imaging findings of the thigh muscles of a 15-year-old boy with Bethlem myopathy diagnosed with clinical, electromyographic and histopathological criteria. Ultrasound and MR showed hyperechoic appearance and high signal intensity on T1- and T2-weighted sequences respectively at the periphery of the vastus lateralis and the long head of the biceps femoris muscles, and at a central area within the rectus femoris muscles. RTE was employed to examine the elastic properties of the muscle. The elastograms were presented as colour-coded maps superimposed on the B-mode images and revealed that the elastographic pattern correlated with the MR and US pattern of involvement. The abnormal muscle areas were stiffer (blue) than the normal-appearing areas (green), a finding that probably correlates with the presence of dystrophic collagen at the affected areas. This report suggests that RTE could be used as an additional imaging tool to evaluate the pattern of muscle changes in congenital myopathy. Further studies are needed to investigate the specificity and clinical value of RTE in the diagnosis and monitoring of neuromuscular disease. (orig.)

  2. Magnetic resonance imaging, ultrasound and real-time ultrasound elastography of the thigh muscles in congenital muscle dystrophy

    International Nuclear Information System (INIS)

    Drakonaki, Eleni E.; Allen, Gina M.

    2010-01-01

    Congenital muscle dystrophy includes a range of genetic disorders characterized by muscle weakness and contractures. We report the magnetic resonance (MR), ultrasound (US) and real-time sonoelastography (RTE) imaging findings of the thigh muscles of a 15-year-old boy with Bethlem myopathy diagnosed with clinical, electromyographic and histopathological criteria. Ultrasound and MR showed hyperechoic appearance and high signal intensity on T1- and T2-weighted sequences respectively at the periphery of the vastus lateralis and the long head of the biceps femoris muscles, and at a central area within the rectus femoris muscles. RTE was employed to examine the elastic properties of the muscle. The elastograms were presented as colour-coded maps superimposed on the B-mode images and revealed that the elastographic pattern correlated with the MR and US pattern of involvement. The abnormal muscle areas were stiffer (blue) than the normal-appearing areas (green), a finding that probably correlates with the presence of dystrophic collagen at the affected areas. This report suggests that RTE could be used as an additional imaging tool to evaluate the pattern of muscle changes in congenital myopathy. Further studies are needed to investigate the specificity and clinical value of RTE in the diagnosis and monitoring of neuromuscular disease. (orig.)

  3. A deep learning approach for real time prostate segmentation in freehand ultrasound guided biopsy.

    Science.gov (United States)

    Anas, Emran Mohammad Abu; Mousavi, Parvin; Abolmaesumi, Purang

    2018-06-01

    Targeted prostate biopsy, incorporating multi-parametric magnetic resonance imaging (mp-MRI) and its registration with ultrasound, is currently the state-of-the-art in prostate cancer diagnosis. The registration process in most targeted biopsy systems today relies heavily on accurate segmentation of ultrasound images. Automatic or semi-automatic segmentation is typically performed offline prior to the start of the biopsy procedure. In this paper, we present a deep neural network based real-time prostate segmentation technique during the biopsy procedure, hence paving the way for dynamic registration of mp-MRI and ultrasound data. In addition to using convolutional networks for extracting spatial features, the proposed approach employs recurrent networks to exploit the temporal information among a series of ultrasound images. One of the key contributions in the architecture is to use residual convolution in the recurrent networks to improve optimization. We also exploit recurrent connections within and across different layers of the deep networks to maximize the utilization of the temporal information. Furthermore, we perform dense and sparse sampling of the input ultrasound sequence to make the network robust to ultrasound artifacts. Our architecture is trained on 2,238 labeled transrectal ultrasound images, with an additional 637 and 1,017 unseen images used for validation and testing, respectively. We obtain a mean Dice similarity coefficient of 93%, a mean surface distance error of 1.10 mm and a mean Hausdorff distance error of 3.0 mm. A comparison of the reported results with those of a state-of-the-art technique indicates statistically significant improvement achieved by the proposed approach. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Ultrasound pregnancy

    Science.gov (United States)

    Pregnancy sonogram; Obstetric ultrasonography; Obstetric sonogram; Ultrasound - pregnancy; IUGR - ultrasound; Intrauterine growth - ultrasound; Polyhydramnios - ultrasound; Oligohydramnios - ultrasound; ...

  5. Non-linear Imaging using an Experimental Synthetic Aperture Real Time Ultrasound Scanner

    DEFF Research Database (Denmark)

    Rasmussen, Joachim; Du, Yigang; Jensen, Jørgen Arendt

    2011-01-01

    This paper presents the first non-linear B-mode image of a wire phantom using pulse inversion attained via an experimental synthetic aperture real-time ultrasound scanner (SARUS). The purpose of this study is to implement and validate non-linear imaging on SARUS for the further development of new...... non-linear techniques. This study presents non-linear and linear B-mode images attained via SARUS and an existing ultrasound system as well as a Field II simulation. The non-linear image shows an improved spatial resolution and lower full width half max and -20 dB resolution values compared to linear...

  6. Ultrasound Research Scanner for Real-time Synthetic Aperture Data Acquisition

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Holm, Ole; Jensen, Lars Joost

    2005-01-01

    Conventional ultrasound systems acquire ultrasound data sequentially one image line at a time. The architecture of these systems is therefore also sequential in nature and processes most of the data in a sequential pipeline. This often makes it difficult to implement radically different imaging...... and 3D B-mode and velocity imaging using advanced coded emissions. The system can be used with 128 element transducers and can excite 128 transducer elements and receive and sample data from 64 channels simultaneously at 40 MHz with 12 bits precision. Two-to-one multiplexing in receive can be used...

  7. Quantification of complex blood flow using real-time in vivo vector flow ultrasound

    DEFF Research Database (Denmark)

    Pedersen, Mads Møller; Pihl, Michael Johannes; Haugaard, Per

    2010-01-01

    A quantitative method for distinguishing complex from non-complex flow patterns in ultrasound is presented. A new commercial BK Medical ultrasound scanner uses the Transverse Oscillation vector flow technique for visualising flow patterns in real-time. In vivo vector flow data of the blood flow...... patterns of the common carotid artery and the carotid bulb were obtained simultaneously as the basis for quantifying complex flow. The carotid bifurcation of two healthy volunteers were scanned. The presence of complex flow patterns from eight cardiac cycles were evaluated by three experts in medical...... for automatic detection of complex flow patterns....

  8. A 10 MHz Bandwidth Continuous-Time Delta-Sigma Modulator for Portable Ultrasound Scanners

    DEFF Research Database (Denmark)

    Llimos Muntal, Pere; Jørgensen, Ivan Harald Holger; Bruun, Erik

    2016-01-01

    comparator and a pull-down clocked latch. The feedback signal is generated with voltage DACs based on transmission gates. Using this implementation, a small and low-power solution required for portable ultrasound scanner applications is achieved. The modulator has a bandwidth of 10 MHz with an oversampling......A fourth-order 1-bit continuous-time delta-sigma modulator designed in a 65 nm process for portable ultrasound scanners is presented in this paper. The loop filter consists of RCintegrators, with programmable capacitor arrays and resistors, and the quantizer is implemented with a high-speed clocked...

  9. Evaluation of automatic time gain compensated in-vivo ultrasound sequences

    DEFF Research Database (Denmark)

    Axelsen, Martin Christian; Røeboe, Kristian Frostholm; Hemmsen, Martin Christian

    2010-01-01

    algorithm for automatic time gain compensation (TGC) on in-vivo ultrasound sequences. Forty ultrasound sequences were recorded from the abdomen of two healthy volunteers. Each sequence of 5 sec was recorded with 40 frames/sec. Post processing each frame, a mask is created wherein anechoic and hyper echoic...... regions are mapped. Near field hyper intensity and deep areas with low signal strength are also included in the mask. The algorithm uses this mask to create a parallel image where anechoic and hyper echoic regions are eliminated. From this, the mean power is calculated as a function of depth. The power...

  10. Complex blood flow quantification using real-time in vivo vector flow ultrasound

    DEFF Research Database (Denmark)

    Pedersen, Mads Møller; Pihl, Michael Johannes; Per, Haugaard

    A new method to define and quantify complex blood flow is presented. The standard deviations of real-time in vivo vector flow angle estimates are used. Using vector flow ultrasound imaging both carotid bifurcations of two healthy volunteers were scanned. Scanning was performed with a 7.6 MHz linear...... transducer (8670, B-K Medical, Denmark) and a commercial vector flow ultrasound scanner (ProFocus 2202, B-K Medical). Eight video sequences of one cardiac cycle were obtained. In every frame boxes were placed to define the common carotid artery(box1) and the carotid bulb(box2). The standard deviation...... for the vector angle estimates was calculated for each box in every frame. For comparison three ultrasound experts evaluated the presence of complex flow in every box. The trial was blinded. For every sequence the mean standard deviation of the vector angle estimates were calculated for box1 {39...

  11. The feasibility of an infrared system for real-time visualization and mapping of ultrasound fields

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, Adam; Nunn, John, E-mail: adam.shaw@npl.co.u [National Physical Laboratory, Teddington, Middlesex, TW11 0LW (United Kingdom)

    2010-06-07

    In treatment planning for ultrasound therapy, it is desirable to know the 3D structure of the ultrasound field. However, mapping an ultrasound field in 3D is very slow, with even a single planar raster scan taking typically several hours. Additionally, hydrophones that are used for field mapping are expensive and can be damaged in some therapy fields. So there is value in rapid methods which enable visualization and mapping of the ultrasound field in about 1 min. In this note we explore the feasibility of mapping the intensity distribution by measuring the temperature distribution produced in a thin sheet of absorbing material. A 0.2 mm thick acetate sheet forms a window in the wall of a water tank containing the transducer. The window is oriented at 45{sup 0} to the beam axis, and the distance from the transducer to the window can be varied. The temperature distribution is measured with an infrared camera; thermal images of the inclined plane could be viewed in real time or images could be captured for later analysis and 3D field reconstruction. We conclude that infrared thermography can be used to gain qualitative information about ultrasound fields. Thermal images are easily visualized with good spatial and thermal resolutions (0.044 mm and 0.05 {sup 0}C in our system). The focus and field structure such as side lobes can be identified in real time from the direct video output. 3D maps and image planes at arbitrary orientations to the beam axis can be obtained and reconstructed within a few minutes. In this note we are primarily interested in the technique for characterization of high intensity focused ultrasound (HIFU) fields, but other applications such as physiotherapy fields are also possible. (note)

  12. The feasibility of an infrared system for real-time visualization and mapping of ultrasound fields

    International Nuclear Information System (INIS)

    Shaw, Adam; Nunn, John

    2010-01-01

    In treatment planning for ultrasound therapy, it is desirable to know the 3D structure of the ultrasound field. However, mapping an ultrasound field in 3D is very slow, with even a single planar raster scan taking typically several hours. Additionally, hydrophones that are used for field mapping are expensive and can be damaged in some therapy fields. So there is value in rapid methods which enable visualization and mapping of the ultrasound field in about 1 min. In this note we explore the feasibility of mapping the intensity distribution by measuring the temperature distribution produced in a thin sheet of absorbing material. A 0.2 mm thick acetate sheet forms a window in the wall of a water tank containing the transducer. The window is oriented at 45 0 to the beam axis, and the distance from the transducer to the window can be varied. The temperature distribution is measured with an infrared camera; thermal images of the inclined plane could be viewed in real time or images could be captured for later analysis and 3D field reconstruction. We conclude that infrared thermography can be used to gain qualitative information about ultrasound fields. Thermal images are easily visualized with good spatial and thermal resolutions (0.044 mm and 0.05 0 C in our system). The focus and field structure such as side lobes can be identified in real time from the direct video output. 3D maps and image planes at arbitrary orientations to the beam axis can be obtained and reconstructed within a few minutes. In this note we are primarily interested in the technique for characterization of high intensity focused ultrasound (HIFU) fields, but other applications such as physiotherapy fields are also possible. (note)

  13. Real-time ultrasound elastography: an assessment of enlarged cervical lymph nodes.

    Science.gov (United States)

    Lo, Wu-Chia; Cheng, Po-Wen; Wang, Chi-Te; Liao, Li-Jen

    2013-09-01

    To determine the efficacy of real-time elastography (RTE), compared with our previously proposed prediction model, in the detection of malignancy in cervical lymph nodes (LNs). One hundred and thirty-one patients underwent ultrasound-guided fine needle aspiration biopsy (ultrasound FNAB) after ultrasound and RTE evaluation. The formula of the RTE scoring system was a four-point visual scale, based on a previously determined model. The formula of the prediction model was: [Formula: see text]. An extended model was constructed with four previous predictors and elasticity scores, using a logistic regression model. Final histology revealed 77 benign and 54 malignant LNs. In the elasticity score system, sensitivity was 66.7 %, specificity was 57.1 %, the positive predictive value (PPV) was 52.2 % and the negative predictive value (NPV) was 71.0 %. In the prediction model system, sensitivity was 79.6 %, specificity was 92.2 %, the PPV was 87.8 % and the NPV was 86.6 %. When the extended and the original model were compared, the areas under the receiver operating characteristic curve (c-statistic) was 0.94 and 0.95, respectively (P > 0.05). Qualitative RTE offers no additional value over conventional ultrasound in predicting malignancy in cervical LNs. • An ultrasound system can help in the assessment of cervical lymph nodes. • Grey-scale and power Doppler ultrasound remain fundamental for neck nodal evaluation. • Qualitative real-time elastography provided no additional value compared with current prediction models.

  14. Effective in vitro and in vivo gene delivery by the combination of liposomal bubbles (bubble liposomes) and ultrasound exposure.

    Science.gov (United States)

    Suzuki, Ryo; Maruyama, Kazuo

    2010-01-01

    Gene delivery with a physical mechanism using ultrasound (US) and nano/microbubbles is expected as an ideal system in terms of delivering plasmid DNA noninvasively into a specific target site. We developed novel liposomal bubbles (Bubble liposomes (BLs)) containing the lipid nanobubbles of perfluoropropane which were utilized for contrast enhancement in ultrasonography. BLs were smaller in diameter than conventional microbubbles and induced cavitation upon exposure ultrasound. In addition, when coupled with US exposure, BLs could deliver plasmid DNA into various types of cells in vitro and in vivo. The transfection efficiency with BLs and US was higher than that with conventional lipofection method. Therefore, the combination of BLs and US might be an efficient and novel nonviral gene delivery system.

  15. The development and evaluation of ultrasound for the treatment of bacterial suspensions. A study of frequency, power and sonication time on cultured Bacillus species.

    Science.gov (United States)

    Joyce, E; Phull, S S; Lorimer, J P; Mason, T J

    2003-10-01

    Some species of bacteria produce colonies and spores which agglomerate in spherical clusters (Bacillus subtilis) and this serves as a protection for the organisms inside against biocidal attack. Flocs of fine particles e.g. clay can entrap bacteria which can also protect them against the biocides. It is because of problems such as these that alternative methods of disinfecting water are under active investigation. One such method is the use of power ultrasound, either alone or in combination with other methods. Ultrasound is able to inactivate bacteria and deagglomerate bacterial clusters or flocs through a number of physical, mechanical and chemical effects arising from acoustic cavitation. The aim of this study was to investigate the effect of power ultrasound at different powers and frequencies on Bacillus subtilis. Viable plate count techniques were used as a measure of microbial activity. Results showed a significant increase in percent kill for Bacillus species with increasing duration of exposure and intensity of ultrasound in the low-kilohertz range (20 and 38 kHz). Results obtained at two higher frequencies (512 and 850 kHz) indicated a significant increase in bacteria count suggesting declumping. In assessing the bacterial kill with time under different sonication regimes three types of behaviour were characterized: High power ultrasound (lower frequencies) in low volumes of bacterial suspension results in a continuous reduction in bacterial cell numbers i.e. the kill rate predominates. High power ultrasound (lower frequencies) in larger volumes results in an initial rise in cell numbers suggesting declumping of the bacteria but this initial rise then falls as the declumping finishes and the kill rate becomes more important. Low intensity ultrasound (higher frequencies) gives an initial rise in cell numbers as a result of declumping. The kill rate is low and so there is no significant subsequent decrease in bacterial cell numbers.

  16. Robotic 4D ultrasound solution for real-time visualization and teleoperation

    Directory of Open Access Journals (Sweden)

    Al-Badri Mohammed

    2017-09-01

    Full Text Available Automation of the image acquisition process via robotic solutions offer a large leap towards resolving ultrasound’s user-dependency. This paper, as part of a larger project aimed to develop a multipurpose 4d-ultrasonic force-sensitive robot for medical applications, focuses on achieving real-time remote visualisation for 4d ultrasound image transfer. This was possible through implementing our software modification on a GE Vivid 7 Dimension workstation, which operates a matrix array probe controlled by a KUKA LBR iiwa 7 7-DOF robotic arm. With the help of robotic positioning and the matrix array probe, fast volumetric imaging of target regions was feasible. By testing ultrasound volumes, which were roughly 880 kB in size, while using gigabit Ethernet connection, a latency of ∼57 ms was achievable for volume transfer between the ultrasound station and a remote client application, which as a result allows a frame count of 17.4 fps. Our modification thus offers for the first time real-time remote visualization, recording and control of 4d ultrasound data, which can be implemented in teleoperation.

  17. Muscle ultrasound quantifies disease progression over time in infants and young boys with duchenne muscular dystrophy.

    Science.gov (United States)

    Zaidman, Craig M; Malkus, Elizabeth C; Connolly, Anne M

    2015-09-01

    Quantitative muscle ultrasound (QUS) in boys with Duchenne muscular dystrophy (DMD) shows increased echointensity as muscle is replaced with fat and fibrosis. Studies of quantitative ultrasound in infants/young boys with DMD over time have not been reported. We used calibrated muscle backscatter (cMB), a reproducible measure of ultrasound echointensity, to quantify muscle pathology in 5 young boys with DMD (ages 0.5-2.8 years) over 17-29 months. We compared the results with repeated assessments of function (n = 4) and with muscle ultrasound images from a cross-section of 6 male controls (0.6-3.1 years). cMB in boys with DMD increased (worsened) over time (P < 0.001), whereas function improved. After age 2 years, cMB in most (4 of 5) boys with DMD was higher than in any control. QUS measures disease progression in young boys with DMD despite functional improvements. QUS could be employed as an outcome measure for serial assessment of young boys with DMD. © 2015 Wiley Periodicals, Inc.

  18. System Architecture of an Experimental Synthetic Aperture Real-Time Ultrasound System

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Hansen, Martin; Tomov, Borislav Gueorguiev

    2007-01-01

    is done using a parametric beam former. Code synthesized for a Xilinx V4FX100 speed grade 11 FPGA can operate at a maximum clock frequency of 167.8 MHz producing 1 billion I and Q samples/second sufficient for real time SA imaging. The system is currently in production, and all boards have been laid out......Synthetic Aperture (SA) ultrasound imaging has many advantages in terms of flexibility and accuracy. One of the major drawbacks is, however, that no system exists, which can implement SA imaging in real time due to the very high number of calculations amounting to roughly 1 billion complex focused...... samples per second per receive channel. Real time imaging is a key aspect in ultrasound, and to truly demonstrate the many advantages of SA imaging, a system usable in the clinic should be made. The paper describes a system capable of real time SA B-mode and vector flow imaging. The Synthetic Aperture...

  19. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... frequently used to evaluate the reproductive and urinary systems. Ultrasound is safe, noninvasive and does not use ... and evaluate a variety of urinary and reproductive system disorders in both sexes without x-ray exposure. ...

  20. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... tip of the transducer is smaller than the standard speculum used when performing a Pap test . A ... both sexes without x-ray exposure. Risks For standard diagnostic ultrasound , there are no known harmful effects ...

  1. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... sexes without x-ray exposure. Risks For standard diagnostic ultrasound , there are no known harmful effects on ... and Resources RTAnswers.org Radiation Therapy for Gynecologic Cancers Radiation Therapy for Prostate Cancer top of page ...

  2. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... the ovaries. Transvaginal ultrasound also evaluates the myometrium (muscular walls of the uterus). Sonohysterography allows for a ... and evaluate a variety of urinary and reproductive system disorders in both sexes without x-ray exposure. ...

  3. Ultrasound stimulation on bone healing. The optimization of stimulation time

    International Nuclear Information System (INIS)

    Rosim, R.C.; Paulin, J.B.P.; Goncalves, R.P.

    1990-01-01

    Previous works in ultrasonic simulation of bone healing dealt with parameters optimization. Albertin (1983) studied the stimulation time and found forty minutes as ideal. However, this stimulation time was the largest one employed and remained some doubt about the most appropriated value. 30, 40, 50 and 60 minutes of stimulation time were selected, while others parameters were held constant with: pulse width in 200 μs, repetition rate in 1000 pulses per second and amplitude in 30 V. Partial incomplete transverse osteotomies were done in the middle third of radio in the right forearm of rabbits. Twenty four animals divided in four subgroups, with 6 animals each were stimulated. The daily stimulation time for each subgroup was 30, 40, 50 and minutes respectively, during 15 consecutive days. The stimulation procedure started 24 hours after surgery. After the stimulation period, radiological, histological and morphometric evaluations were done and greater bone healing was found for the 50 minutes stimulation subgroup, in them new bone was also prominent. (author)

  4. Real-time exposure fusion on a mobile computer

    CSIR Research Space (South Africa)

    Bachoo, AK

    2009-12-01

    Full Text Available information in these scenarios. An image captured using a short exposure time will not saturate bright image re- gions while an image captured with a long exposure time will show more detail in the dark regions. The pixel depth provided by most camera.... The auto exposure also creates strong blown-out highlights in the foreground (the grass patch). The short shutter time (Exposure 1) correctly exposes the grass while the long shutter time (Exposure 3) is able to correctly expose the camouflaged dummy...

  5. System Level Design of a Continuous-Time Delta-Sigma Modulator for Portable Ultrasound Scanners

    DEFF Research Database (Denmark)

    Llimos Muntal, Pere; Færch, Kjartan; Jørgensen, Ivan Harald Holger

    2015-01-01

    In this paper the system level design of a continuous-time ∆Σ modulator for portable ultrasound scanners is presented. The overall required signal-to-noise ratio (SNR) is derived to be 42 dB and the sampling frequency used is 320 MHz for an oversampling ratio of 16. In order to match these requir......, based on high-level VerilogA simulations, the performance of the ∆Σ modulator versus various block performance parameters is presented as trade-off curves. Based on these results, the block specifications are derived.......In this paper the system level design of a continuous-time ∆Σ modulator for portable ultrasound scanners is presented. The overall required signal-to-noise ratio (SNR) is derived to be 42 dB and the sampling frequency used is 320 MHz for an oversampling ratio of 16. In order to match...

  6. Measuring the diameter of rising gas bubbles by means of the ultrasound transit time technique

    Energy Technology Data Exchange (ETDEWEB)

    Richter, T., E-mail: Thomas.Richter6@tu-dresden.de; Eckert, K., E-mail: Kerstin.Eckert@tu-dresden.de; Yang, X.; Odenbach, S.

    2015-09-15

    Highlights: • Ultrasound transit time technique (UTTT) is applied to the zig-zag raise of gas bubble. • Comparison of bubble diameter and tilt, measured by UTTT, with high-speed imaging. • Uncertainty in the determination of the bubble diameter by UTTT is less than 7%. • UTTT is able to measure dynamic changes in bubble size in opaque liquids and vessels. • UTTT can be applied to liquid metal loops. - Abstract: This study presents ultrasound transit time technique (UTTT) measurements of the diameter variations of single argon bubbles rising in a zig-zag trajectory in water. Simultaneous size measurements with a high-speed camera show that UTTT resolves both the apparent diameter and the tilt of the bubble axis with an accuracy of better than 7%. This qualifies UTTT for the measurement of bubble sizes in opaque liquids, such as liquid metals, or vessels.

  7. High amplitude ultrasound pulse generation using time-reversal through a multiple scattering medium

    OpenAIRE

    ARNAL , Bastien; Pernot , Mathieu; Fink , Mathias; Tanter , Mickaël

    2012-01-01

    International audience; In histotripsy, soft tissues can be fragmented using very high pressure ultrasound pulses. Using time-reversal cavity is a way to generate high pressure pulses with a limited number of acoustic sources. The principle was already demonstrated by Montaldo et al. using a solid metal cavity, but low transmission coefficient was obtained due to the strong impedance mismatch at the metal/water interface. We propose here to use a waveguide filled with water containing a 2D mu...

  8. Comparison of a novel real-time SonixGPS needle-tracking ultrasound technique with traditional ultrasound for vascular access in a phantom gel model.

    Science.gov (United States)

    Kopac, Daniel S; Chen, Jerry; Tang, Raymond; Sawka, Andrew; Vaghadia, Himat

    2013-09-01

    Ultrasound-guided percutaneous vascular access for endovascular procedures is well established in surgical practice. Despite this, rates of complications from venous and arterial access procedures remain a significant cause of morbidity. We hypothesized that the use of a new technique of vascular access using an ultrasound with a novel needle-guidance positioning system (GPS) would lead to improved success rates of vascular puncture for both in-plane and out-of-plane techniques compared with traditional ultrasound. A prospective, randomized crossover study of medical students from all years of medical school was conducted using a phantom gel model. Each medical student performed three ultrasound-guided punctures with each of the four modalities (in-plane no GPS, in-plane with GPS, out-of-plane no GPS, out-of-plane with GPS) for a total of 12 attempts. The success or failure was judged by the ability to aspirate a simulated blood solution from the model. The time to successful puncture was also recorded. A poststudy validated NASA Task Load Index workload questionnaire was conducted to assess the student's perceptions of the two different techniques. A total of 30 students completed the study. There was no significant difference seen in the mean times of vascular access for each of the modalities. Higher success rates for vascular access using the GPS for both the in-plane (94% vs 91%) and the out-of-plane (86% vs 70%) views were observed; however, this was not statistically significant. The students perceived the mental demand (median 12.0 vs 14.00; P = .035) and effort to be lower (mean 11.25 vs 14.00; P = .044) as well as the performance to be higher (mean 15.50 vs 14.00; P = .041) for the GPS vs the traditional ultrasound-guided technique. Students also perceived their ability to access vessels increased with the aid of the GPS (7.00 vs 6.50; P = .007). The majority of students expressed a preference for GPS (26/30, 87%) as opposed to the traditional counterpart

  9. Time-activity relationships to VOC personal exposure factors

    Science.gov (United States)

    Edwards, Rufus D.; Schweizer, Christian; Llacqua, Vito; Lai, Hak Kan; Jantunen, Matti; Bayer-Oglesby, Lucy; Künzli, Nino

    Social and demographic factors have been found to play a significant role in differences between time-activity patterns of population subgroups. Since time-activity patterns largely influence personal exposure to compounds as individuals move across microenvironments, exposure subgroups within the population may be defined by factors that influence daily activity patterns. Socio-demographic and environmental factors that define time-activity subgroups also define quantifiable differences in VOC personal exposures to different sources and individual compounds in the Expolis study. Significant differences in exposures to traffic-related compounds ethylbenzene, m- and p-xylene and o-xylene were observed in relation to gender, number of children and living alone. Categorization of exposures further indicated time exposed to traffic at work and time in a car as important determinants. Increased exposures to decane, nonane and undecane were observed for males, housewives and self-employed. Categorization of exposures indicated exposure subgroups related to workshop use and living downtown. Higher exposures to 3-carene and α-pinene commonly found in household cleaning products and fragrances were associated with more children, while exposures to traffic compounds ethylbenzene, m- and p-xylene and o-xylene were reduced with more children. Considerable unexplained variation remained in categorization of exposures associated with home product use and fragrances, due to individual behavior and product choice. More targeted data collection methods in VOC exposure studies for these sources should be used. Living alone was associated with decreased exposures to 2-methyl-1-propanol and 1-butanol, and traffic-related compounds. Identification of these subgroups may help to reduce the large amount of unexplained variation in VOC exposure studies. Further they may help in assessing impacts of urban planning that result in changes in behavior of individuals, resulting in shifts in

  10. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... ultrasound. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time ...

  11. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... D images. A Doppler ultrasound study may be part of an ultrasound examination. Doppler ultrasound , also called ... terms of the distance traveled per unit of time, rather than as a color picture. It can ...

  12. 2D array transducers for real-time 3D ultrasound guidance of interventional devices

    Science.gov (United States)

    Light, Edward D.; Smith, Stephen W.

    2009-02-01

    We describe catheter ring arrays for real-time 3D ultrasound guidance of devices such as vascular grafts, heart valves and vena cava filters. We have constructed several prototypes operating at 5 MHz and consisting of 54 elements using the W.L. Gore & Associates, Inc. micro-miniature ribbon cables. We have recently constructed a new transducer using a braided wiring technology from Precision Interconnect. This transducer consists of 54 elements at 4.8 MHz with pitch of 0.20 mm and typical -6 dB bandwidth of 22%. In all cases, the transducer and wiring assembly were integrated with an 11 French catheter of a Cook Medical deployment device for vena cava filters. Preliminary in vivo and in vitro testing is ongoing including simultaneous 3D ultrasound and x-ray fluoroscopy.

  13. Does the real-time ultrasound guidance provide safer venipuncture in implantable venous port implantation?

    Science.gov (United States)

    Yıldırım, İlknur; Tütüncü, Ayşe Çiğdem; Bademler, Süleyman; Özgür, İlker; Demiray, Mukaddes; Karanlık, Hasan

    2018-03-01

    To examine whether the real-time ultrasound-guided venipuncture for implantable venous port placement is safer than the traditional venipuncture. The study analyzed the results of 2153 venous ports placed consecutively from January 2009 to January 2016. A total of 922 patients in group 1 and 1231 patients in group 2 were admitted with venous port placed using the traditional landmark subclavian approach and real-time ultrasound-guided axillary approach, respectively. Sociodemographic characteristics of patients, early (pneumothorax, pinch-off syndrome, arterial puncture, hematoma, and malposition arrhythmia) and late (deep vein thrombosis, obstruction, infection, erosion-dehiscence, and rotation of the port chamber) complications and the association of these complications with the implantation method were evaluated. There were no significant differences in the sociodemographic characteristics of the patients between the two groups. The overall and early complications in group 2 were significantly lower than those in group 1. Pinch-off syndrome only developed in group 1. Seven patients and two patients had pneumothorax in groups 1 and 2, respectively. Puncture number was significantly associated with the development of the overall complications. The ultrasound-guided axillary approach may be preferred as a method to reduce the risk of both early and late complications. Large, randomized, controlled prospective trials will be helpful in determining a safer implantable venous port implantation technique.

  14. Ultrasound Collaboration across Europe: An EFSUMB success story in politically troubled times?

    Science.gov (United States)

    Sidhu, P S

    2016-10-01

    the benchmark for ultrasound practice across the world and are often mimicked by others.This collaboration and continued output is important. With the recent Food and Drug Administration (United States of America) approval of the use of an ultrasound contrast agent for focal liver lesions, a worldwide change of practice will occur. This was achieved without a clinical trial in children, a previously unheard of occurrence and solely based on the experience, expertise and pioneering activities of investigators in Europe, many embolden by the support of colleagues across Europe sharing experience through EFSUMB. The lead in establishing ultrasound elastography has also originated in Europe with close and strong collaboration to produce guidelines, again pioneering the application of elastography to clinical situations. More important guidelines are on the horizon dealing with liver elastography, non-hepatic contrast ultrasound and gastrointestinal ultrasound.This success translates to the success of the journal, Ultraschall in der Medizine/European Journal of Ultrasound, with a rising impact factor, rising manuscript submissions and limited space. Where can authors in Europe publish their innovative research to continue this journey? This is one of the pitfalls of the European success story, perhaps in time we can resolve this by increasing on-line papers, increasing page numbers in the journal etc. but this is a problem of the publication industry in general.The most important element from this success story has to be the success of collaboration across the borders of the European nations, and this has also to be the success of the European Union in achieving this close scientific and medical environment. The potential adverse effect this will have on the scientific collaboration in the United Kingdom, my own area of professional activity, following a vote to re-consider membership of the European Union, is largely unpredictable. Nevertheless this is of great concern to

  15. Prostate Ultrasound

    Medline Plus

    Full Text Available ... the patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... blood test result. difficulty urinating. Because ultrasound provides real-time images, it also can be used to guide ...

  16. Influence of contrast agent dose and ultrasound exposure on cardiomyocyte injury induced by myocardial contrast echocardiography in rats.

    Science.gov (United States)

    Miller, Douglas L; Li, Peng; Dou, Chunyan; Gordon, David; Edwards, Chris A; Armstrong, William F

    2005-10-01

    To detect specific cardiomyocyte injury induced by myocardial contrast material-enhanced echocardiography (ie, myocardial contrast echocardiography) in rats and to ascertain the influences of contrast material dose and ultrasound exposure on this injury. All animal procedures were approved by the university committee for the use and care of animals. Myocardial contrast echocardiography with 1:4 electrocardiographic (ECG) triggering was performed at 1.5 MHz in 61 anesthetized rats. Evans blue (EB) dye was injected as the vital stain for cardiomyocyte injury. At the start of myocardial contrast echocardiography, which lasted 10 minutes, perflutren lipid microsphere-based contrast material was infused through the tail vein for 5 minutes. Premature heartbeats were counted from the ECG record. The numbers of EB-stained cells counted on sections of heart specimens obtained 24 hours after myocardial contrast echocardiography and then either fresh frozen or embedded in paraffin were determined by using fluorescence microscopy. Results were compared statistically by using t tests and Mann-Whitney rank sum tests. EB-stained cells were concentrated in the anterior region of the myocardium. In the paraffin-embedded specimens, EB-stained cells were often accompanied by but largely separate from areas of inflammatory cell infiltration. At end-systolic triggering with a 50 microL/kg dose of microsphere contrast material, the EB-stained cell count increased with increasing peak rarefactional pressure amplitude, with significantly increased cell counts at 1.6 MPa (P .1). EB-stained cell counts increased with increasing contrast material dose, from 10 to 50 microL/kg, at 2.0 MPa. Cardiomyocyte injury was induced by the interaction of ultrasound pulses with contrast agent microbubbles during myocardial contrast echocardiography in rats, and the numbers of injured cells increased with increasing contrast agent dose and ultrasound exposure. RSNA, 2005

  17. Stem-cell-activated organ following ultrasound exposure: better transplant option for organ transplantation.

    Science.gov (United States)

    Wang, Sen; Li, Yu; Ji, Ying-Chang; Lin, Chang-Min; Man, Cheng; Zheng, Xiao-Xuan

    2010-01-01

    Although doctors try their best to protect transplants during surgery, there remain great challenges for the higher survival rate and less rejection of transplants after organ transplantation. Growing evidence indicates that the stem cells could function after injury rather than aging, implying that suitable injury may activate the stem cells of damaged organs. Furthermore, it has been revealed that stem cells can be used to induce tolerance in transplantation and the ultrasound has great biological effects on organs. Basing on these facts, we hypothesize that the stem cells within the transplants can be activated by ultrasound with high-frequency and medium-intensity. Therefore, the stem-cell-activated organs (SCAO) can be derived, and the SCAO will be better transplant option for organ transplantation. We postulate the ultrasound can change the molecular activity and/or quantity of the stem cells, the membrane permeability, the cell-cell junctions, and their surrounding microenvironments. As a result, the stem cells are activated, and the SCAO will acquire more regenerative capacity and less rejection. In the paper, we also discuss the process, methods and models for verifying the theory, and the consequences. We believe the theory may provide a practical method for the clinical application of the ultrasound and stem cells in organ transplantation.

  18. Time reversal and phase coherent music techniques for super-resolution ultrasound imaging

    Science.gov (United States)

    Huang, Lianjie; Labyed, Yassin

    2018-05-01

    Systems and methods for super-resolution ultrasound imaging using a windowed and generalized TR-MUSIC algorithm that divides the imaging region into overlapping sub-regions and applies the TR-MUSIC algorithm to the windowed backscattered ultrasound signals corresponding to each sub-region. The algorithm is also structured to account for the ultrasound attenuation in the medium and the finite-size effects of ultrasound transducer elements. A modified TR-MUSIC imaging algorithm is used to account for ultrasound scattering from both density and compressibility contrasts. The phase response of ultrasound transducer elements is accounted for in a PC-MUSIC system.

  19. Real-Time MRI Navigated Ultrasound for Preoperative Tumor Evaluation in Breast Cancer Patients: Technique and Clinical Implementation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ah Young; Seo, Bo Kyoung [Department of Radiology, Korea University Ansan Hospital, Korea University College of Medicine, Ansan 15355 (Korea, Republic of)

    2016-11-01

    Real-time magnetic resonance imaging (MRI) navigated ultrasound is an image fusion technique to display the results of both MRI and ultrasonography on the same monitor. This system is a promising technique to improve lesion detection and analysis, to maximize advantages of each imaging modality, and to compensate the disadvantages of both MRI and ultrasound. In evaluating breast cancer stage preoperatively, MRI and ultrasound are the most representative imaging modalities. However, sometimes difficulties arise in interpreting and correlating the radiological features between these two different modalities. This pictorial essay demonstrates the technical principles of the real-time MRI navigated ultrasound, and clinical implementation of the system in preoperative evaluation of tumor extent, multiplicity, and nodal status in breast cancer patients.

  20. Real-time MRI navigated ultrasound for preoperative tumor evaluation in breast cancer patients: Technique and clinical implementation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ah Young; Seo, Bo Kyoung [Dept. of Radiology, Korea University Ansan Hospital, Korea University College of Medicine, Ansan (Korea, Republic of)

    2016-09-15

    Real-time magnetic resonance imaging (MRI) navigated ultrasound is an image fusion technique to display the results of both MRI and ultrasonography on the same monitor. This system is a promising technique to improve lesion detection and analysis, to maximize advantages of each imaging modality, and to compensate the disadvantages of both MRI and ultrasound. In evaluating breast cancer stage preoperatively, MRI and ultrasound are the most representative imaging modalities. However, sometimes difficulties arise in interpreting and correlating the radiological features between these two different modalities. This pictorial essay demonstrates the technical principles of the real-time MRI navigated ultrasound, and clinical implementation of the system in preoperative evaluation of tumor extent, multiplicity, and nodal status in breast cancer patients.

  1. Influence of exposure time on toxicity-An overview.

    Science.gov (United States)

    Connell, Des W; Yu, Qiming J; Verma, Vibha

    2016-04-29

    Data on toxicity of chemicals is usually reported as the LD50, or LC50, with the exposure time from experimental testing in the laboratory reported. But the exposure time is not considered to be a quantifiable variable which can be used to evaluate its importance in expressed toxicity, often described in general terms such as acute, chronic and so on. For the last hundred years Habers Rule has been successfully used to extrapolate from reported exposure times to other exposure times which may be needed for setting standards, health risk assessments and other applications. But it has limitations particularly in environmental applications where exposure levels are low and exposure times are relatively long. The Reduced Life Expectancy (RLE) model overcomes these problems and can be utilised under all exposure conditions. It can be expressed as ln(LT50)=-a (LC50)(ν)+b where the constants ν, a and b can be evaluated by fitting the model to experimental data on the LC50, and corresponding LT50, together with the Normal Life Expectancy (NLE) of the organism being considered as a data point when the LC50 is zero. The constant, ν, at a value of unity gives a linear relationship and where νmodel for fish, invertebrates and mammals involving 115 data sets and with a wide range of organic and inorganic toxicants the RLE model gave correlation coefficients of >0.8 with 107 sets of data. The RLE model can be used to extrapolate from a limited data set on exposure times and corresponding LT50 values to any exposure time and corresponding LT50 value. The discrepancy between Haber's Rule and RLE model increases as the exposure time increases. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  2. Cystic change in thyroid nodules: A confounding factor for real-time qualitative thyroid ultrasound elastography

    Energy Technology Data Exchange (ETDEWEB)

    Bhatia, K.S.S.; Rasalkar, D.P.; Lee, Y.P.; Wong, K.T.; King, A.D.; Yuen, H.Y. [Department of Imaging and Interventional Radiology, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin N.T, Hong Kong (Hong Kong); Ahuja, A.T., E-mail: aniltahuja@cuhk.edu.hk [Department of Imaging and Interventional Radiology, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin N.T, Hong Kong (Hong Kong)

    2011-09-15

    Objective: To evaluate real-time qualitative ultrasound elastography for focal thyroid masses undergoing fine-needle aspiration in a routine thyroid ultrasound clinic. Materials and methods: Ninety-four thyroid nodules scheduled for fine-needle aspiration cytology in a thyroid ultrasound clinic also underwent real-time freehand elastography. Colour-scaled elastograms were graded visually on the stiffness of the solid component of nodules relative to thyroid parenchyma using an elastography score (ES) scale from 1 (soft) to 4 (stiff). The ES for benign and malignant nodules and the influence of cystic change on ES were analysed using Chi-square with trend and Fishers exact tests, with a p < 0.05 used to indicate statistical significance. Results: There were 19 papillary carcinomas, five metastases, 57 hyperplastic nodules, and four follicular adenomas based on definitive cytology (n = 54) or histology (n = 31). Nine nodules were excluded due to indeterminate cytology and no histology. Of malignancies (all solid), two were ES = 1, four were ES = 2, eight were ES = 3, and 10 were ES = 4. Of benign nodules, 17 were ES = 1, 17 were ES = 2, 16 were ES = 3, and 11 were ES = 4. An ES > 2 was more common in benign nodules with predominant cystic components (17/18) than mildly cystic (3/12) or completely solid (7/31) benign nodules (p = 0.0004, p < 0.0001). The ES was not significantly different between benign and malignant nodules (p = 0.09) unless partially cystic nodules were excluded (p = 0.005). For solid nodules, an ES > 2 optimally predicted malignancy, achieving 74% sensitivity, 77% specificity, and 76% accuracy. Conclusion: Qualitative real-time thyroid elastography predicts malignancy only if predominantly cystic nodules are excluded, which may limit its utility in routine clinical practice.

  3. Comparison of the time required for removal of intraradicular cast posts using two Brazilian ultrasound devices

    Directory of Open Access Journals (Sweden)

    Manoel Brito-Júnior

    2009-03-01

    Full Text Available The aim of this in vitro study was to compare the time required for removal of intraradicular cast posts cemented with zinc phosphate (ZF or glass ionomer cement (GIC, using two Brazilian ultrasound devices (BUD. Seventy two human inferior premolars with single root canals were sectioned transversally at the cementoenamel junction. In each specimen, the root canal was endodontically treated, the post space was prepared to a depth of 9 mm and the canal was molded to obtain a post impression. After the casting procedures, the posts were randomly distributed into 2 groups (n = 36 according to the luting material used: G1 - ZF and G2 - GIC. The tooth and luted post set was then embedded in an acrylic resin block. The groups were then divided into 3 subgroups (n = 12 according to the ultrasound device used: A - Enac (Osada Electric, Japan, used as a control group; B - Profi II Ceramic (Dabi Atlante, Brazil and C - Jet Sonic Satelec (Gnatus, Brazil. The posts were submitted to the vibration process with maximum power set on all surrounding surfaces. Time of application was recorded with a chronometer until complete post dislodgment, and the data were analyzed by the ANOVA test (p < 0.05. The averages required for post removal in G1 and G2 were respectively 41.42 and 92.03 seconds, with significant statistical difference (p = 0.001. No statistical difference was observed among the three ultrasound devices (p = 0.088, and the BUD presented a performance similar to that of the international gold standard device (Enac. Moreover, the type of luting agent had a greater influence on the time required for post removal than the origin of the ultrasonic unit.

  4. A multimodal instrument for real-time in situ study of ultrasound and cavitation mediated drug delivery

    OpenAIRE

    Bian, S; Seth, A; Daly, D; Carlisle, R; Stride, E

    2017-01-01

    The development of a multimodal instrument capable of real-time in situ measurements of cavitation activity and effect in tissue mimicking phantoms during ultrasound and cavitation mediated drug delivery experiments is described here. The instrument features an acoustic arm that can expose phantoms to high-intensity focused-ultrasound while measuring cavitation activity and an optical arm that monitors cavitation effect using confocal microscopy. This combination of modalities allows real-tim...

  5. Multi-processor system for real-time deconvolution and flow estimation in medical ultrasound

    DEFF Research Database (Denmark)

    Jensen, Jesper Lomborg; Jensen, Jørgen Arendt; Stetson, Paul F.

    1996-01-01

    of the algorithms. Many of the algorithms can only be properly evaluated in a clinical setting with real-time processing, which generally cannot be done with conventional equipment. This paper therefore presents a multi-processor system capable of performing 1.2 billion floating point operations per second on RF...... filter is used with a second time-reversed recursive estimation step. Here it is necessary to perform about 70 arithmetic operations per RF sample or about 1 billion operations per second for real-time deconvolution. Furthermore, these have to be floating point operations due to the adaptive nature...... interfaced to our previously-developed real-time sampling system that can acquire RF data at a rate of 20 MHz and simultaneously transmit the data at 20 MHz to the processing system via several parallel channels. These two systems can, thus, perform real-time processing of ultrasound data. The advantage...

  6. Diaphragmatic paralysis evaluated by phrenic nerve stimulation during fluoroscopy or real-time ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    McCauley, R.G.K.; Labib, K.B.

    1984-10-01

    Stimulation of the phrenic nerve by supplying an electrical impulse to the neck during fluoroscopy or real-time ultrasound (sonoscopy) of the diaphragm allows more precise functional evaluation than fluoroscopy and/or sonoscopy alone. This is especially true of patients who are unable to cooperate because the are on a ventilator, unconscious, or very young. The authors cite cases in which diaphragmatic paralysis was diagnosed by conventional methods but stimulation of the phrenic nerve demonstrated good diaphragmatic motion, leading to a change in prognosis in some cases and a change in therapy in others.

  7. Diaphragmatic paralysis evaluated by phrenic nerve stimulation during fluoroscopy or real-time ultrasound

    International Nuclear Information System (INIS)

    McCauley, R.G.K.; Labib, K.B.

    1984-01-01

    Stimulation of the phrenic nerve by supplying an electrical impulse to the neck during fluoroscopy or real-time ultrasound (sonoscopy) of the diaphragm allows more precise functional evaluation than fluoroscopy and/or sonoscopy alone. This is especially true of patients who are unable to cooperate because the are on a ventilator, unconscious, or very young. The authors cite cases in which diaphragmatic paralysis was diagnosed by conventional methods but stimulation of the phrenic nerve demonstrated good diaphragmatic motion, leading to a change in prognosis in some cases and a change in therapy in others

  8. Effects of Chronic Exposure to Ultrasound of Alternating Frequencies on the Levels of Aggression and Anxiety in CBA and BALB/c mice.

    Science.gov (United States)

    Pavlov, D A; Gorlova, A V; Ushakova, V M; Zubkov, E A; Morozova, A Yu; Inozemtsev, A N; Chekhonin, V P

    2017-08-01

    Stress-induced changes in the behavior of CBA and BALB/c mice were studied after 3-week ultrasound exposure (22-45 kHz). The mice of both lines demonstrated increased aggression in the resident-intruder and social interest paradigms and reduced number of social interactions in the social interest test. Elevated plus maze test showed a decrease in anxiety level in CBA mice and an increase in this parameter in BALB/c mice. Chronic exposure to ultrasound induced an increase in aggression level in mice of both lines that was not directly related to changes in anxiety level.

  9. Effect of exposure time and image resolution on fractal dimension

    International Nuclear Information System (INIS)

    An, Byung Mo; Heo, Min Suk; Lee, Seung Pyo; Lee, Sam Sun; Choi, Soon Chul; Park, Tae Won; Kim, Jong Dae

    2002-01-01

    To evaluate the effect of exposure time and image resolution on fractal dimension calculations for determining the optimal range of these two variances. Thirty-one radiographs of the mandibular angle area of sixteen human dry mandibles were taken at different exposure times (0.01, 0.08, 0.16, 0.25, 0.40, 0.64, and 0.80 s). Each radiograph was digitized at 1200 dpi, 8 bit, 256 gray level using a film scanner. We selected an Region of Interest (ROI) that corresponded to the same region as in each radiograph, but the resolution of ROI was degraded to 1000, 800, 600, 500, 400, 300, 200, and 100 dpi. The fractal dimension was calculated by using the tile-counting method for each image, and the calculated values were then compared statistically. As the exposure time and the image resolution increased, the mean value of the fractal dimension decreased, except the case where exposure time was set at 0.01 seconds (alpha = 0.05). The exposure time and image resolution affected the fractal dimension by interaction (p<0.001). When the exposure time was set to either 0.64 seconds or 0.80 seconds, the resulting fractal dimensions were lower, irrespective of image resolution, than at shorter exposure times (alpha = 0.05). The optimal range for exposure time and resolution was determined to be 0.08-0.40 seconds and from 400-1000 dpi, respectively. Adequate exposure time and image resolution is essential for acquiring the fractal dimension using tile-counting method for evaluation of the mandible.

  10. Suitability of the echo-time-shift method as laboratory standard for thermal ultrasound dosimetry

    Science.gov (United States)

    Fuhrmann, Tina; Georg, Olga; Haller, Julian; Jenderka, Klaus-Vitold

    2017-03-01

    Ultrasound therapy is a promising, non-invasive application with potential to significantly improve cancer therapies like surgery, viro- or immunotherapy. This therapy needs faster, cheaper and more easy-to-handle quality assurance tools for therapy devices as well as possibilities to verify treatment plans and for dosimetry. This limits comparability and safety of treatments. Accurate spatial and temporal temperature maps could be used to overcome these shortcomings. In this contribution first results of suitability and accuracy investigations of the echo-time-shift method for two-dimensional temperature mapping during and after sonication are presented. The analysis methods used to calculate time-shifts were a discrete frame-to-frame and a discrete frame-to-base-frame algorithm as well as a sigmoid fit for temperature calculation. In the future accuracy could be significantly enhanced by using continuous methods for time-shift calculation. Further improvements can be achieved by improving filtering algorithms and interpolation of sampled diagnostic ultrasound data. It might be a comparatively accurate, fast and affordable method for laboratory and clinical quality control.

  11. Windowed time-reversal music technique for super-resolution ultrasound imaging

    Science.gov (United States)

    Huang, Lianjie; Labyed, Yassin

    2018-05-01

    Systems and methods for super-resolution ultrasound imaging using a windowed and generalized TR-MUSIC algorithm that divides the imaging region into overlapping sub-regions and applies the TR-MUSIC algorithm to the windowed backscattered ultrasound signals corresponding to each sub-region. The algorithm is also structured to account for the ultrasound attenuation in the medium and the finite-size effects of ultrasound transducer elements.

  12. Prostate Ultrasound

    Medline Plus

    Full Text Available ... be able to give a clearer picture of soft tissues that do not show up well on x-ray images. Ultrasound causes no health problems and may be repeated as often as is necessary if medically indicated. Ultrasound provides real-time imaging, making it a good tool for guiding ...

  13. Prostate Ultrasound

    Science.gov (United States)

    ... be able to give a clearer picture of soft tissues that do not show up well on x-ray images. Ultrasound causes no health problems and may be repeated as often as is necessary if medically indicated. Ultrasound provides real-time imaging, making it a good tool for guiding ...

  14. Prostate Ultrasound

    Medline Plus

    Full Text Available ... the best way to see if treatment is working or if a finding is stable or changed over time. top of page What are the benefits vs. risks? Benefits Ultrasound is widely available, easy-to-use and less expensive than other imaging methods. Ultrasound imaging uses ...

  15. Online 4D ultrasound guidance for real-time motion compensation by MLC tracking.

    Science.gov (United States)

    Ipsen, Svenja; Bruder, Ralf; O'Brien, Rick; Keall, Paul J; Schweikard, Achim; Poulsen, Per R

    2016-10-01

    With the trend in radiotherapy moving toward dose escalation and hypofractionation, the need for highly accurate targeting increases. While MLC tracking is already being successfully used for motion compensation of moving targets in the prostate, current real-time target localization methods rely on repeated x-ray imaging and implanted fiducial markers or electromagnetic transponders rather than direct target visualization. In contrast, ultrasound imaging can yield volumetric data in real-time (3D + time = 4D) without ionizing radiation. The authors report the first results of combining these promising techniques-online 4D ultrasound guidance and MLC tracking-in a phantom. A software framework for real-time target localization was installed directly on a 4D ultrasound station and used to detect a 2 mm spherical lead marker inside a water tank. The lead marker was rigidly attached to a motion stage programmed to reproduce nine characteristic tumor trajectories chosen from large databases (five prostate, four lung). The 3D marker position detected by ultrasound was transferred to a computer program for MLC tracking at a rate of 21.3 Hz and used for real-time MLC aperture adaption on a conventional linear accelerator. The tracking system latency was measured using sinusoidal trajectories and compensated for by applying a kernel density prediction algorithm for the lung traces. To measure geometric accuracy, static anterior and lateral conformal fields as well as a 358° arc with a 10 cm circular aperture were delivered for each trajectory. The two-dimensional (2D) geometric tracking error was measured as the difference between marker position and MLC aperture center in continuously acquired portal images. For dosimetric evaluation, VMAT treatment plans with high and low modulation were delivered to a biplanar diode array dosimeter using the same trajectories. Dose measurements with and without MLC tracking were compared to a static reference dose using 3%/3 mm and 2

  16. Real-time ultrasound image classification for spine anesthesia using local directional Hadamard features.

    Science.gov (United States)

    Pesteie, Mehran; Abolmaesumi, Purang; Ashab, Hussam Al-Deen; Lessoway, Victoria A; Massey, Simon; Gunka, Vit; Rohling, Robert N

    2015-06-01

    Injection therapy is a commonly used solution for back pain management. This procedure typically involves percutaneous insertion of a needle between or around the vertebrae, to deliver anesthetics near nerve bundles. Most frequently, spinal injections are performed either blindly using palpation or under the guidance of fluoroscopy or computed tomography. Recently, due to the drawbacks of the ionizing radiation of such imaging modalities, there has been a growing interest in using ultrasound imaging as an alternative. However, the complex spinal anatomy with different wave-like structures, affected by speckle noise, makes the accurate identification of the appropriate injection plane difficult. The aim of this study was to propose an automated system that can identify the optimal plane for epidural steroid injections and facet joint injections. A multi-scale and multi-directional feature extraction system to provide automated identification of the appropriate plane is proposed. Local Hadamard coefficients are obtained using the sequency-ordered Hadamard transform at multiple scales. Directional features are extracted from local coefficients which correspond to different regions in the ultrasound images. An artificial neural network is trained based on the local directional Hadamard features for classification. The proposed method yields distinctive features for classification which successfully classified 1032 images out of 1090 for epidural steroid injection and 990 images out of 1052 for facet joint injection. In order to validate the proposed method, a leave-one-out cross-validation was performed. The average classification accuracy for leave-one-out validation was 94 % for epidural and 90 % for facet joint targets. Also, the feature extraction time for the proposed method was 20 ms for a native 2D ultrasound image. A real-time machine learning system based on the local directional Hadamard features extracted by the sequency-ordered Hadamard transform for

  17. Real-time Ultrasound Assessment of Astronaut Spinal Anatomy and Disorders on the International Space Station.

    Science.gov (United States)

    Garcia, Kathleen M; Harrison, Michael F; Sargsyan, Ashot E; Ebert, Douglas; Dulchavsky, Scott A

    2018-04-01

    Back pain is one of the most common conditions of astronauts during spaceflight and is hypothesized to be attributed to pathologic anatomic changes. Ultrasound (US) represents the only available imaging modality on the International Space Station, but a formal US protocol for imaging the structures of the spinal column does not exist. This investigation developed a method of acquiring diagnostic-quality images of the anterior lumbar and cervical regions of the spine during long-duration spaceflight. Comprehensive spinal US examinations were conducted on 7 long-duration spaceflight astronauts before flight, in flight, and after flight and compared to preflight and postflight magnetic resonance imaging data. In-flight scans were conducted after just-in-time training assisted by remote expert tele-US guidance. Novice users were able to obtain diagnostic-quality spinal images with a 92.5% success rate. Thirty-three anomalous or pathologic findings were identified during the preflight US analysis, and at least 14 new findings or progressions were identified during the postflight US analysis. Common findings included disk desiccation, osteophytes, and qualitative changes in the intervertebral disk height and angle. Ultrasound has proven efficacy as a portable and versatile diagnostic imaging modality under austere conditions. We demonstrated a potential role for US to evaluate spinal integrity and alterations in the extreme environment of space on the International Space Station. Further investigations should be performed to corroborate this imaging technique and to create a larger database related to in-flight spinal conditions during long-duration spaceflight. © 2017 by the American Institute of Ultrasound in Medicine.

  18. Real-time personal exposure and health condition monitoring system

    Energy Technology Data Exchange (ETDEWEB)

    Saitou, Isamu; Kanda, Hiroaki; Asai, Akio; Takeishi, Naoki; Ota, Yoshito [Hitachi Aloka Medical, Ltd., Measuring Systems Engineering Dept., Tokyo (Japan); Hanawa, Nobuhiro; Ueda, Hisao; Kusunoki, Tsuyoshi; Ishitsuka, Etsuo; Kawamura, Hiroshi [Japan Atomic Energy Agency, Oarai Research and Development Center, Oarai, Ibaraki (Japan)

    2012-03-15

    JAEA (Japan Atomic Energy Agency) and HAM (Hitachi Aloka Medical, Ltd) have proposed novel monitoring system for workers of nuclear facility. In these facilities, exposure management for workers is mainly used access control and personal exposure recordings. This system is currently only for reports management but is not confirmative for surveillance when work in progress. Therefore, JAEA and HAM integrate access control and personal exposure recordings and two real-time monitoring systems which are position sensing and vital sign monitor. Furthermore change personal exposure management to real-time management, this system integration prevents workers from risk of accidents, and makes possible take appropriate action quickly. This novel system is going to start for tentative operation, using position sensing and real-time personal dosimeter with database in Apr. 2012. (author)

  19. Core review: physician-performed ultrasound: the time has come for routine use in acute care medicine.

    Science.gov (United States)

    Royse, Colin F; Canty, David J; Faris, John; Haji, Darsim L; Veltman, Michael; Royse, Alistair

    2012-11-01

    The use of ultrasound in the acute care specialties of anesthesiology, intensive care, emergency medicine, and surgery has evolved from discrete, office-based echocardiographic examinations to the real-time or point-of-care clinical assessment and interventions. "Goal-focused" transthoracic echocardiography is a limited scope (as compared with comprehensive examination) echocardiographic examination, performed by the treating clinician in acute care medical practice, and is aimed at addressing specific clinical concerns. In the future, the practice of surface ultrasound will be integrated into the everyday clinical practice as ultrasound-assisted examination and ultrasound-guided procedures. This evolution should start at the medical student level and be reinforced throughout specialist training. The key to making ultrasound available to every physician is through education programs designed to facilitate uptake, rather than to prevent access to this technology and education by specialist craft groups. There is evidence that diagnosis is improved with ultrasound examination, yet data showing change in management and improvement in patient outcome are few and an important area for future research.

  20. Imaging of implant needles for real-time HDR-brachytherapy prostate treatment using biplane ultrasound transducers.

    Science.gov (United States)

    Siebert, Frank-André; Hirt, Markus; Niehoff, Peter; Kovács, György

    2009-08-01

    Ultrasound imaging is becoming increasingly important in prostate brachytherapy. In high-dose-rate (HDR) real-time planning procedures the definition of the implant needles is often performed by transrectal ultrasound. This article describes absolute measurements of the visibility and accuracy of manual detection of implant needle tips and compares measurement results of different biplane ultrasound systems in transversal and longitudinal (i.e., sagittal) ultrasound modes. To obtain a fixed coordinate system and stable conditions the measurements were carried out in a water tank using a dedicated marker system. Needles were manually placed in the phantom until the observer decided by the real-time ultrasound image that the zero position was reached. A comparison of three different ultrasound systems yielded an offset between 0.8 and 3.1 mm for manual detection of the needle tip in ultrasound images by one observer. The direction of the offset was discovered to be in the proximal direction, i.e., the actual needle position was located more distally compared to the ultrasound-based definition. In the second part of the study, the ultrasound anisotropy of trocar implant needles is reported. It was shown that the integrated optical density in a region of interest around the needle tip changes with needle rotation. Three peaks were observed with a phase angle of 120 degrees. Peaks appear not only in transversal but also in longitudinal ultrasound images, with a phase shift of 60 degrees. The third section of this study shows results of observer dependent influences on needle tip detection in sagittal ultrasound images considering needle rotation. These experiments were carried out using the marker system in a water tank. The needle tip was placed exactly at the position z=0 mm. It was found that different users tend to differently interpret the same ultrasound images. The needle tip was manually detected five times in the ultrasound images by three experienced observers

  1. Laser ultrasound and simulated time reversal on bulk waves for non destructive control

    International Nuclear Information System (INIS)

    Diot, G; Walaszek, H; Kouadri-David, A; Guégan, S; Flifla, J

    2014-01-01

    Laser welding of aluminium generally creates embedded welding defects, such as porosities or cracks. Non Destructive Inspection (NDI) after processing may ensure an acceptable weld quality by defect detection. Nowadays, NDI techniques used to control the inside of a weld are mainly limited to X-Rays or ultrasonics. The current paper describes the use of a Laser Ultrasound (LU) technique to inspect porosities in 2 and 4-mm thick sheet lap welds. First experimentations resulted in the detection of 0.5-mm drilled holes in bulk aluminium sheets. The measurement of the depth of these defects is demonstrated too. Further experimentations shows the applicability of the LU technique to detect porosities in aluminium laser welds. However, as the interpretation of raw measures is limiting the detection capacity of this technique, we developed a signal processing using Time-Reversal capabilities to enhance detection capacities. Furthermore, the signal processing output is a geometrical image of the material's inner state, increasing the ease of interpretation. It is based on a mass-spring simulation which enables the back-propagation of the acquired ultrasound signal. The spring-mass simulation allows the natural generation of all the different sound waves and thus enables the back-propagation of a raw signal without any need of filtering or wave identification and extraction. Therefore the signal processing uses the information contained in the compression wave as well as in the shear wave

  2. Automated hierarchical time gain compensation for in-vivo ultrasound imaging

    Science.gov (United States)

    Moshavegh, Ramin; Hemmsen, Martin C.; Martins, Bo; Brandt, Andreas H.; Hansen, Kristoffer L.; Nielsen, Michael B.; Jensen, Jørgen A.

    2015-03-01

    Time gain compensation (TGC) is essential to ensure the optimal image quality of the clinical ultrasound scans. When large fluid collections are present within the scan plane, the attenuation distribution is changed drastically and TGC compensation becomes challenging. This paper presents an automated hierarchical TGC (AHTGC) algorithm that accurately adapts to the large attenuation variation between different types of tissues and structures. The algorithm relies on estimates of tissue attenuation, scattering strength, and noise level to gain a more quantitative understanding of the underlying tissue and the ultrasound signal strength. The proposed algorithm was applied to a set of 44 in vivo abdominal movie sequences each containing 15 frames. Matching pairs of in vivo sequences, unprocessed and processed with the proposed AHTGC were visualized side by side and evaluated by two radiologists in terms of image quality. Wilcoxon signed-rank test was used to evaluate whether radiologists preferred the processed sequences or the unprocessed data. The results indicate that the average visual analogue scale (VAS) is positive ( p-value: 2.34 × 10-13) and estimated to be 1.01 (95% CI: 0.85; 1.16) favoring the processed data with the proposed AHTGC algorithm.

  3. Real-time interpolation for true 3-dimensional ultrasound image volumes.

    Science.gov (United States)

    Ji, Songbai; Roberts, David W; Hartov, Alex; Paulsen, Keith D

    2011-02-01

    We compared trilinear interpolation to voxel nearest neighbor and distance-weighted algorithms for fast and accurate processing of true 3-dimensional ultrasound (3DUS) image volumes. In this study, the computational efficiency and interpolation accuracy of the 3 methods were compared on the basis of a simulated 3DUS image volume, 34 clinical 3DUS image volumes from 5 patients, and 2 experimental phantom image volumes. We show that trilinear interpolation improves interpolation accuracy over both the voxel nearest neighbor and distance-weighted algorithms yet achieves real-time computational performance that is comparable to the voxel nearest neighbor algrorithm (1-2 orders of magnitude faster than the distance-weighted algorithm) as well as the fastest pixel-based algorithms for processing tracked 2-dimensional ultrasound images (0.035 seconds per 2-dimesional cross-sectional image [76,800 pixels interpolated, or 0.46 ms/1000 pixels] and 1.05 seconds per full volume with a 1-mm(3) voxel size [4.6 million voxels interpolated, or 0.23 ms/1000 voxels]). On the basis of these results, trilinear interpolation is recommended as a fast and accurate interpolation method for rectilinear sampling of 3DUS image acquisitions, which is required to facilitate subsequent processing and display during operating room procedures such as image-guided neurosurgery.

  4. A Continuous-Time Delta-Sigma ADC for Portable Ultrasound Scanners

    DEFF Research Database (Denmark)

    Llimos Muntal, Pere; Jørgensen, Ivan Harald Holger; Bruun, Erik

    2017-01-01

    A fully differential fourth-order 1-bit continuous-time delta-sigma ADC designed in a 65nm process for portable ultrasound scanners is presented in this paper. The circuit design, implementation and measurements on the fabricated die are shown. The loop filter consists of RC-integrators, programmable...... capacitor arrays, resistors and voltage feedback DACs. The quantizer contains a pulse generator, a high-speed clocked comparator and a pull-down clocked latch to ensure constant delay in the feedback loop. Using this implementation, a small and low-power solution required for portable ultrasound scanner...... applications is achieved. The converter has a supply voltage of 1.2V, a bandwidth of 10MHz and an oversampling ratio of 16 leading to an operating frequency of 320MHz. The design occupies a die area of 0.0175mm2. Simulations with extracted parasitics show a SNR of 45.2dB and a current consumption of 489 µ...

  5. Real-time contrast-enhanced ultrasound in diagnosing of focal spleen lesions

    International Nuclear Information System (INIS)

    Yu Xiaoling; Yu Jie; Liang Ping; Liu Fangyi

    2012-01-01

    Objective: To investigate the features of focal spleen lesions (FSLs) on contrast-enhanced ultrasound (CEUS) imaging. Materials and methods: CEUS with a blot injection of SonoVue was performed in 48 patients with 75 FSLs (median diameter 2.6 cm) and their perfusion characteristics were analyzed by using contrast pulse sequences (CPS) technique. Results: Among 19 malignant lesions (10 metastases, 7 lymphoma, 1 hemangiosarcoma, 1 epithelioid hemangioendothelioma) and 56 benign lesion (23 hemangiomas, 14 cysts, 8 infarctions, 4 splenic ruptures, 3 tuberculosis, 2 abscess, 1 pseudoaneurysm, 1 lymphangioma), 25 benign lesions were demonstrated nonenhancement. For malignancy, 50.0% (5/10) metastases and 57.1% (4/7) lymphomas were showed hypoenhancement in the arterial phase, and 18 (94.7%) of malignant lesions were hypo-enhancement in the parenchymal phase. Among 31 benign lesions with enhancement, 27 (87.1%) were showed isoenhancement or hyperenhancement in the arterial phase and 22 (71.0%) lesions were isoenhancement or hyperenhancement in the parenchymal phase. The sensitivity, specificity and accuracy of diagnosis for FSLs were 91.1%, 95.0% and 92.0% for CEUS and 75.0%, 84.2% and 77.3% respectively, for the conventional baseline ultrasound (BUS). Conclusion: Real-time CEUS can provide valuable information for the diagnosis and differential diagnosis of FSLs.

  6. Effect of Electroconvulsive Therapy on Cognitive Functions of Rats with Depression-Like Disorders Induced by Ultrasound Exposure.

    Science.gov (United States)

    Ushakova, V M; Zubkov, E A; Morozova, A Y; Gorlova, A V; Pavlov, D A; Inozemtsev, A N; Chekhonin, V P

    2017-09-01

    We studied the effect of electroconvulsive therapy on cognitive functions in rats with depression-like disorder caused by exposure to ultrasound of varying frequency (20-45 kHz). Object recognition and Morris water-maze tests revealed no negative effects of the therapy on memory. Moreover, positive effect of therapy was demonstrated that manifested in amelioration of memory disturbances in depression-like disorders in these behavioral tests. The results of this study do not support the idea about side effects of electroconvulsive therapy, in particular, development of transient amnesia, and are a prerequisite for a more thorough study of internal mechanisms of the effect of the therapy on cognitive sphere.

  7. Two-dimensional Shear Wave Elastography on Conventional Ultrasound Scanners with Time Aligned Sequential Tracking (TAST) and Comb-push Ultrasound Shear Elastography (CUSE)

    Science.gov (United States)

    Song, Pengfei; Macdonald, Michael C.; Behler, Russell H.; Lanning, Justin D.; Wang, Michael H.; Urban, Matthew W.; Manduca, Armando; Zhao, Heng; Callstrom, Matthew R.; Alizad, Azra; Greenleaf, James F.; Chen, Shigao

    2014-01-01

    Two-dimensional (2D) shear wave elastography presents 2D quantitative shear elasticity maps of tissue, which are clinically useful for both focal lesion detection and diffuse disease diagnosis. Realization of 2D shear wave elastography on conventional ultrasound scanners, however, is challenging due to the low tracking pulse-repetition-frequency (PRF) of these systems. While some clinical and research platforms support software beamforming and plane wave imaging with high PRF, the majority of current clinical ultrasound systems do not have the software beamforming capability, which presents a critical challenge for translating the 2D shear wave elastography technique from laboratory to clinical scanners. To address this challenge, this paper presents a Time Aligned Sequential Tracking (TAST) method for shear wave tracking on conventional ultrasound scanners. TAST takes advantage of the parallel beamforming capability of conventional systems and realizes high PRF shear wave tracking by sequentially firing tracking vectors and aligning shear wave data in the temporal direction. The Comb-push Ultrasound Shear Elastography (CUSE) technique was used to simultaneously produce multiple shear wave sources within the field-of-view (FOV) to enhance shear wave signal-to-noise-ratio (SNR) and facilitate robust reconstructions of 2D elasticity maps. TAST and CUSE were realized on a conventional ultrasound scanner (the General Electric LOGIQ E9). A phantom study showed that the shear wave speed measurements from the LOGIQ E9 were in good agreement to the values measured from other 2D shear wave imaging technologies. An inclusion phantom study showed that the LOGIQ E9 had comparable performance to the Aixplorer (Supersonic Imagine) in terms of bias and precision in measuring different sized inclusions. Finally, in vivo case analysis of a breast with a malignant mass, and a liver from a healthy subject demonstrated the feasibility of using the LOGIQ E9 for in vivo 2D shear wave

  8. Children's (Pediatric) Abdominal Ultrasound Imaging

    Medline Plus

    Full Text Available ... do not use ionizing radiation (as used in x-rays ), thus there is no radiation exposure to the ... tissues that do not show up well on x-ray images. Ultrasound provides real-time imaging, making it ...

  9. Time-dependent change of blood flow in the prostate treated with high-intensity focused ultrasound.

    Science.gov (United States)

    Shoji, Sunao; Tonooka, Akiko; Hashimoto, Akio; Nakamoto, Masahiko; Tomonaga, Tetsuro; Nakano, Mayura; Sato, Haruhiro; Terachi, Toshiro; Koike, Junki; Uchida, Toyoaki

    2014-09-01

    Avascular areas on contrast-enhanced magnetic resonance imaging have been considered to be areas of localized prostate cancer successfully treated by high-intensity focused ultrasound. However, the optimal timing of magnetic resonance imaging has not been discussed. The thermal effect of high-intensity focused ultrasound is degraded by regional prostatic blood flow. Conversely, the mechanical effect of high-intensity focused ultrasound (cavitation) is not affected by blood flow, and can induce vessel damage. In this series, the longitudinal change of blood flow on contrast-enhanced magnetic resonance imaging was observed from postoperative day 1 to postoperative day 14 in 10 patients treated with high-intensity focused ultrasound. The median rates of increase in the non-enhanced volume of the whole gland, transition zone and peripheral zone from postoperative day 1 to postoperative day 14 were 36%, 39%, and 34%, respectively. In another pathological analysis of the prostate tissue of 17 patients immediately after high-intensity focused ultrasound without neoadjuvant hormonal therapy, we observed diffuse coagulative degeneration and partial non-coagulative prostate tissue around arteries with vascular endothelial cell detachment. These observations on contrast-enhanced magnetic resonance imaging support a time-dependent change of the blood flow in the prostate treated with high-intensity focused ultrasound. Additionally, our pathological findings support the longitudinal changes of these magnetic resonance imaging findings. Further large-scale studies will investigate the most appropriate timing of contrast-enhanced magnetic resonance imaging for evaluation of the effectiveness of high-intensity focused ultrasound for localized prostate cancer. © 2014 The Japanese Urological Association.

  10. Interlaced photoacoustic and ultrasound imaging system with real-time coregistration for ovarian tissue characterization

    Science.gov (United States)

    Alqasemi, Umar; Li, Hai; Yuan, Guangqian; Kumavor, Patrick; Zanganeh, Saeid; Zhu, Quing

    2014-07-01

    Coregistered ultrasound (US) and photoacoustic imaging are emerging techniques for mapping the echogenic anatomical structure of tissue and its corresponding optical absorption. We report a 128-channel imaging system with real-time coregistration of the two modalities, which provides up to 15 coregistered frames per second limited by the laser pulse repetition rate. In addition, the system integrates a compact transvaginal imaging probe with a custom-designed fiber optic assembly for in vivo detection and characterization of human ovarian tissue. We present the coregistered US and photoacoustic imaging system structure, the optimal design of the PC interfacing software, and the reconfigurable field programmable gate array operation and optimization. Phantom experiments of system lateral resolution and axial sensitivity evaluation, examples of the real-time scanning of a tumor-bearing mouse, and ex vivo human ovaries studies are demonstrated.

  11. Ultrasound-Guided Cannulation: Time to Bring Subclavian Central Lines Back

    Directory of Open Access Journals (Sweden)

    Talayeh Rezayat, DO, MPH

    2016-03-01

    Full Text Available Despite multiple advantages, subclavian vein (SCV cannulation via the traditional landmark approach has become less used in comparison to ultrasound (US guided internal jugular catheterization due to a higher rate of mechanical complications. A growing body of evidence indicates that SCV catheterization with real-time US guidance can be accomplished safely and efficiently. While several cannulation approaches with real-time US guidance have been described, available literature suggests that the infraclavicular, longitudinal “in-plane” technique may be preferred. This approach allows for direct visualization of needle advancement, which reduces risk of complications and improves successful placement. Infraclavicular SCV cannulation requires simultaneous use of US during needle advancement, but for an inexperienced operator, it is more easily learned compared to the traditional landmark approach. In this article, we review the evidence supporting the use of US guidance for SCV catheterization and discuss technical aspects of the procedure itself.

  12. Simulation Study of Real Time 3-D Synthetic Aperture Sequential Beamforming for Ultrasound Imaging

    DEFF Research Database (Denmark)

    Hemmsen, Martin Christian; Rasmussen, Morten Fischer; Stuart, Matthias Bo

    2014-01-01

    in the main system. The real-time imaging capability is achieved using a synthetic aperture beamforming technique, utilizing the transmit events to generate a set of virtual elements that in combination can generate an image. The two core capabilities in combination is named Synthetic Aperture Sequential......This paper presents a new beamforming method for real-time three-dimensional (3-D) ultrasound imaging using a 2-D matrix transducer. To obtain images with sufficient resolution and contrast, several thousand elements are needed. The proposed method reduces the required channel count from...... Beamforming (SASB). Simulations are performed to evaluate the image quality of the presented method in comparison to Parallel beamforming utilizing 16 receive beamformers. As indicators for image quality the detail resolution and Cystic resolution are determined for a set of scatterers at a depth of 90mm...

  13. Spatiotemporal evolution of cavitation dynamics exhibited by flowing microbubbles during ultrasound exposure.

    Science.gov (United States)

    Choi, James J; Coussios, Constantin-C

    2012-11-01

    Ultrasound and microbubble-based therapies utilize cavitation to generate bioeffects, yet cavitation dynamics during individual pulses and across consecutive pulses remain poorly understood under physiologically relevant flow conditions. SonoVue(®) microbubbles were made to flow (fluid velocity: 10-40 mm/s) through a vessel in a tissue-mimicking material and were exposed to ultrasound [frequency: 0.5 MHz, peak-rarefactional pressure (PRP): 150-1200 kPa, pulse length: 1-100,000 cycles, pulse repetition frequency (PRF): 1-50 Hz, number of pulses: 10-250]. Radiated emissions were captured on a linear array, and passive acoustic mapping was used to spatiotemporally resolve cavitation events. At low PRPs, stable cavitation was maintained throughout several pulses, thus generating a steady rise in energy with low upstream spatial bias within the focal volume. At high PRPs, inertial cavitation was concentrated in the first 6.3 ± 1.3 ms of a pulse, followed by an energy reduction and high upstream bias. Multiple pulses at PRFs below a flow-dependent critical rate (PRF(crit)) produced predictable and consistent cavitation dynamics. Above the PRF(crit), energy generated was unpredictable and spatially biased. In conclusion, key parameters in microbubble-seeded flow conditions were matched with specific types, magnitudes, distributions, and durations of cavitation; this may help in understanding empirically observed in vivo phenomena and guide future pulse sequence designs.

  14. Assessment of Nicotine Exposure From Active Human Cigarette Smoking Time

    Directory of Open Access Journals (Sweden)

    Cahours Xavier

    2017-09-01

    Full Text Available The burning of a cigarette is a series of consecutive sequences of both passive and active burnings when a smoking cycle is applied to the cigarette. A previous study, using a smoking machine, showed that cigarette nicotine yields are dependent linearly on the difference between the time of smouldering (passive burning and the time of smoking (active burning. It is predicted that the smoker’s nicotine yield increases when the intensity of smoking increases, i.e., when the time to smoke a cigarette (smoking time decreases. Note that observations made on machines might not be comparable to human behaviours. The aim of this study was to determine whether nicotine mouth-level exposure could be predicted through measurement of human smoking time. A smoking behaviour study was conducted to compare human smoking nicotine yields obtained from both filter tip analysis and the cigarette burning time model. Results showed that smokers’ exposure to the smoke depends essentially on the speed at which the cigarette is smoked. An increase in human smoking intensity, resulting in a decrease in smoking time, generates an increase in smoke exposure, whatever the puff number, puff duration, puff volume and filter ventilation (open or blocked. The association of a machine smoking yield with a corresponding smoking time, and the time taken by a consumer to smoke the cigarette would provide information on the exposure to smoke constituents in a simple and effective manner.

  15. Real-time monitoring of focused ultrasound blood-brain barrier opening via subharmonic acoustic emission detection: implementation of confocal dual-frequency piezoelectric transducers

    Science.gov (United States)

    Tsai, Chih-Hung; Zhang, Jia-Wei; Liao, Yi-Yi; Liu, Hao-Li

    2016-04-01

    Burst-tone focused ultrasound exposure in the presence of microbubbles has been demonstrated to be effective at inducing temporal and local opening of the blood-brain barrier (BBB), which promises significant clinical potential to deliver therapeutic molecules into the central nervous system (CNS). Traditional contrast-enhanced imaging confirmation after focused ultrasound (FUS) exposure serves as a post-operative indicator of the effectiveness of FUS-BBB opening, however, an indicator that can concurrently report the BBB status and BBB-opening effectiveness is required to provide effective feedback to implement this treatment clinically. In this study, we demonstrate the use of subharmonic acoustic emission detection with implementation on a confocal dual-frequency piezoelectric ceramic structure to perform real-time monitoring of FUS-BBB opening. A confocal dual-frequency (0.55 MHz/1.1 MHz) focused ultrasound transducer was designed. The 1.1 MHz spherically-curved ceramic was employed to deliver FUS exposure to induce BBB-opening, whereas the outer-ring 0.55 MHz ceramic was employed to detect the subharmonic acoustic emissions originating from the target position. In stage-1 experiments, we employed spectral analysis and performed an energy spectrum density (ESD) calculation. An optimized 0.55 MHz ESD level change was shown to effectively discriminate the occurrence of BBB-opening. Wideband acoustic emissions received from 0.55 MHz ceramics were also analyzed to evaluate its correlations with erythrocyte extravasations. In stage-2 real-time monitoring experiments, we applied the predetermined ESD change as a detection threshold in PC-controlled algorithm to predict the FUS exposure intra-operatively. In stage-1 experiment, we showed that subharmonic ESD presents distinguishable dynamics between intact BBB and opened BBB, and therefore a threshold ESD change level (5.5 dB) can be identified for BBB-opening prediction. Using this ESD change threshold detection as a

  16. Real-time monitoring of focused ultrasound blood-brain barrier opening via subharmonic acoustic emission detection: implementation of confocal dual-frequency piezoelectric transducers

    International Nuclear Information System (INIS)

    Tsai, Chih-Hung; Zhang, Jia-Wei; Liao, Yi-Yi; Liu, Hao-Li

    2016-01-01

    Burst-tone focused ultrasound exposure in the presence of microbubbles has been demonstrated to be effective at inducing temporal and local opening of the blood-brain barrier (BBB), which promises significant clinical potential to deliver therapeutic molecules into the central nervous system (CNS). Traditional contrast-enhanced imaging confirmation after focused ultrasound (FUS) exposure serves as a post-operative indicator of the effectiveness of FUS-BBB opening, however, an indicator that can concurrently report the BBB status and BBB-opening effectiveness is required to provide effective feedback to implement this treatment clinically. In this study, we demonstrate the use of subharmonic acoustic emission detection with implementation on a confocal dual-frequency piezoelectric ceramic structure to perform real-time monitoring of FUS-BBB opening. A confocal dual-frequency (0.55 MHz/1.1 MHz) focused ultrasound transducer was designed. The 1.1 MHz spherically-curved ceramic was employed to deliver FUS exposure to induce BBB-opening, whereas the outer-ring 0.55 MHz ceramic was employed to detect the subharmonic acoustic emissions originating from the target position. In stage-1 experiments, we employed spectral analysis and performed an energy spectrum density (ESD) calculation. An optimized 0.55 MHz ESD level change was shown to effectively discriminate the occurrence of BBB-opening. Wideband acoustic emissions received from 0.55 MHz ceramics were also analyzed to evaluate its correlations with erythrocyte extravasations. In stage-2 real-time monitoring experiments, we applied the predetermined ESD change as a detection threshold in PC-controlled algorithm to predict the FUS exposure intra-operatively. In stage-1 experiment, we showed that subharmonic ESD presents distinguishable dynamics between intact BBB and opened BBB, and therefore a threshold ESD change level (5.5 dB) can be identified for BBB-opening prediction. Using this ESD change threshold detection as a

  17. Towards real-time 3D ultrasound planning and personalized 3D printing for breast HDR brachytherapy treatment

    International Nuclear Information System (INIS)

    Poulin, Eric; Gardi, Lori; Fenster, Aaron; Pouliot, Jean; Beaulieu, Luc

    2015-01-01

    Two different end-to-end procedures were tested for real-time planning in breast HDR brachytherapy treatment. Both methods are using a 3D ultrasound (3DUS) system and a freehand catheter optimization algorithm. They were found fast and efficient. We demonstrated a proof-of-concept approach for personalized real-time guidance and planning to breast HDR brachytherapy treatments

  18. Ultrasound -- Pelvis

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    Full Text Available ... Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding Ovarian Cancer Images related to Ultrasound - Pelvis Sponsored by Please ...

  19. Ultrasound -- Pelvis

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    Full Text Available ... Children's (Pediatric) Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding Ovarian Cancer Images related to Ultrasound - Pelvis Sponsored by Please ...

  20. Ultrasound -- Pelvis

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    Full Text Available ... specific content. Related Articles and Media Sonohysterography Ultrasound - Abdomen Children's (Pediatric) Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Kidney and ...

  1. Radiographic apparatus and method for monitoring film exposure time

    International Nuclear Information System (INIS)

    Vatne, R.S.; Woodmansee, W.E.

    1981-01-01

    In connection with radiographic inspection of structural and industrial materials, method and apparatus are disclosed for automatically determining and displaying the time required to expose a radiographic film positioned to receive radiation passed by a test specimen, so that the finished film is exposed to an optimum blackening (density) for maximum film contrast. A plot is made of the variations in a total exposure parameter (representing the product of detected radiation rate and time needed to cause optimum film blackening) as a function of the voltage level applied to an X-ray tube. An electronic function generator storing the shape of this plot is incorporated into an exposure monitoring apparatus, such that for a selected tube voltage setting, the function generator produces an electrical analog signal of the corresponding exposure parameter. During the exposure, another signal is produced representing the rate of radiation as monitored by a diode detector positioned so as to receive the same radiation that is incident on the film. The signal representing the detected radiation rate is divided, by an electrical divider circuit into the signal representing total exposure, and the resulting quotient is an electrical signal representing the required exposure time. (author)

  2. Time and Place as Modifiers of Personal UV Exposure

    Directory of Open Access Journals (Sweden)

    Brian L. Diffey

    2018-05-01

    Full Text Available It is a common belief that, if we want to limit our sun exposure during outdoor recreational activities and holidays in order to avoid sunburn or reduce our risk of skin cancer, we need to reach for the bottle of sunscreen or cover up with clothing. As important as these measures are, there is another way to enjoy our time outdoors and still benefit from the experience. In this article, we consider the impact of time, place, and behaviour outdoors on our exposure to solar ultraviolet (UV radiation. Some of the simple actions we can take in controlling our UV exposure include being aware of the position of the sun in the sky, understanding how we can use the UV index to guide our outdoor exposure, and the importance of reducing our sun exposure around the middle of the day. Finally we review our preferred holiday activities and destinations, and the influence of outdoor leisure pursuits. By planning where and when we spend our leisure time in the sun, we can maximise our enjoyment whilst limiting our UV exposure.

  3. Time and Place as Modifiers of Personal UV Exposure.

    Science.gov (United States)

    Diffey, Brian L

    2018-05-30

    It is a common belief that, if we want to limit our sun exposure during outdoor recreational activities and holidays in order to avoid sunburn or reduce our risk of skin cancer, we need to reach for the bottle of sunscreen or cover up with clothing. As important as these measures are, there is another way to enjoy our time outdoors and still benefit from the experience. In this article, we consider the impact of time, place, and behaviour outdoors on our exposure to solar ultraviolet (UV) radiation. Some of the simple actions we can take in controlling our UV exposure include being aware of the position of the sun in the sky, understanding how we can use the UV index to guide our outdoor exposure, and the importance of reducing our sun exposure around the middle of the day. Finally we review our preferred holiday activities and destinations, and the influence of outdoor leisure pursuits. By planning where and when we spend our leisure time in the sun, we can maximise our enjoyment whilst limiting our UV exposure.

  4. Prostate Ultrasound

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    Full Text Available ... nodule felt by a physician during a routine physical exam or prostate cancer screening exam. an elevated blood test result. difficulty urinating. Because ultrasound provides real-time ...

  5. Ultrasound -- Pelvis

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    Full Text Available ... use different transducers (with different capabilities) during a single exam. The transducer sends out high-frequency sound ... modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time ...

  6. Prostate Ultrasound

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    Full Text Available ... less than 20 minutes. top of page What will I experience during and after the procedure? Ultrasound ... in the region of the prostate. A biopsy will add time to the procedure. Rarely, a small ...

  7. Ultrasound -- Pelvis

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    Full Text Available ... ultrasound images are reviewed. top of page What will I experience during and after the procedure? For ... in the region of the prostate. A biopsy will add time to the procedure. If a Doppler ...

  8. Ultrasound -- Pelvis

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    Full Text Available ... abdomen, arms, legs, neck and/or brain (in infants and children) or within various body organs such ... and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time imaging, making it a ...

  9. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... be necessary. Your doctor will explain the exact reason why another exam is requested. Sometimes a follow- ... Ultrasound provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as ...

  10. Prostate Ultrasound

    Medline Plus

    Full Text Available ... be necessary. Your doctor will explain the exact reason why another exam is requested. Sometimes a follow- ... Ultrasound provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as ...

  11. Ultrasound -- Pelvis

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    Full Text Available ... the exam. Bringing books, small toys, music or games can help to distract the child and make ... modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time ...

  12. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... the examination process. To ensure a smooth experience, it often helps to explain the procedure to the ... on the amplitude (loudness), frequency (pitch) and time it takes for the ultrasound signal to return from ...

  13. Prostate Ultrasound

    Medline Plus

    Full Text Available ... difficulty urinating or an elevated blood test result. It’s also used to investigate a nodule found during ... difficulty urinating. Because ultrasound provides real-time images, it also can be used to guide procedures such ...

  14. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... ultrasound exams are also used to monitor the health and development of an embryo or fetus during pregnancy. See the ... can help to identify and evaluate a variety of urinary and reproductive system disorders in both sexes without x-ray exposure. ...

  15. Prostate Ultrasound

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    Full Text Available ... do not use ionizing radiation (as used in x-rays ), thus there is no radiation exposure to the ... tissues that do not show up well on x-ray images. Ultrasound causes no health problems and may ...

  16. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... do not use ionizing radiation (as used in x-rays ), thus there is no radiation exposure to the ... tissues that do not show up well on x-ray images. Ultrasound is the preferred imaging modality for ...

  17. A multimodal instrument for real-time in situ study of ultrasound and cavitation mediated drug delivery.

    Science.gov (United States)

    Bian, Shuning; Seth, Anjali; Daly, Dan; Carlisle, Robert; Stride, Eleanor

    2017-03-01

    The development of a multimodal instrument capable of real-time in situ measurements of cavitation activity and effect in tissue mimicking phantoms during ultrasound and cavitation mediated drug delivery experiments is described here. The instrument features an acoustic arm that can expose phantoms to high-intensity focused-ultrasound while measuring cavitation activity and an optical arm that monitors cavitation effect using confocal microscopy. This combination of modalities allows real-time in situ characterisation of drug delivery in tissue and tissue mimicking phantoms during ultrasound and cavitation mediated drug delivery experiments. A representative result, obtained with a tissue mimicking phantom and acoustically activated droplets, is presented here as a demonstration of the instrument's capabilities and potential applications.

  18. Real time elastography endoscopic ultrasound (RTE-EUS), a comprehensive review

    Energy Technology Data Exchange (ETDEWEB)

    Dietrich, C.F., E-mail: christoph.dietrich@ckbm.de [Med. Klinik 2, Caritas-Krankenhaus Bad Mergentheim (Germany); Department of Gastroenterology, Research Center of Gastroenterology and Hepatology, University of Medicine and Pharmacy of Craiova (Romania); Klinik für Innere Medizin, Krankenhaus Märkisch Oderland (Germany); Săftoiu, A.; Jenssen, C. [Med. Klinik 2, Caritas-Krankenhaus Bad Mergentheim (Germany); Department of Gastroenterology, Research Center of Gastroenterology and Hepatology, University of Medicine and Pharmacy of Craiova (Romania); Klinik für Innere Medizin, Krankenhaus Märkisch Oderland (Germany)

    2014-03-15

    Real-time elastography (RTE) performed during endoscopic ultrasound (EUS) is a relatively new technique which allows the evaluation of tissue stiffness, with the intent of better characterising lesions during EUS examinations. The aim of this comprehensive review was to describe the technique of RTE-EUS, as well as the clinical applications, including the study of pancreatic lesions, but also hepatobiliary, gastrointestinal (GI) tract pathology (including anal canal), lymph nodes, adrenal glands, lung and mediastinum, as well as urogenital applications. One of the advantages of the RTE-EUS technique is especially the possibility to be used in various locations accessible from the GI tract. Future developments are also briefly discussed, as elastography is a tissue characterising technique that will certainly not replace biopsy, but will rather be an adjunct during EUS examinations, due to its ease of use and low cost.

  19. Real time elastography endoscopic ultrasound (RTE-EUS), a comprehensive review

    International Nuclear Information System (INIS)

    Dietrich, C.F.; Săftoiu, A.; Jenssen, C.

    2014-01-01

    Real-time elastography (RTE) performed during endoscopic ultrasound (EUS) is a relatively new technique which allows the evaluation of tissue stiffness, with the intent of better characterising lesions during EUS examinations. The aim of this comprehensive review was to describe the technique of RTE-EUS, as well as the clinical applications, including the study of pancreatic lesions, but also hepatobiliary, gastrointestinal (GI) tract pathology (including anal canal), lymph nodes, adrenal glands, lung and mediastinum, as well as urogenital applications. One of the advantages of the RTE-EUS technique is especially the possibility to be used in various locations accessible from the GI tract. Future developments are also briefly discussed, as elastography is a tissue characterising technique that will certainly not replace biopsy, but will rather be an adjunct during EUS examinations, due to its ease of use and low cost

  20. Real-time control of focused ultrasound heating based on rapid MR thermometry.

    Science.gov (United States)

    Vimeux, F C; De Zwart, J A; Palussiére, J; Fawaz, R; Delalande, C; Canioni, P; Grenier, N; Moonen, C T

    1999-03-01

    Real-time control of the heating procedure is essential for hyperthermia applications of focused ultrasound (FUS). The objective of this study is to demonstrate the feasibility of MRI-controlled FUS. An automatic control system was developed using a dedicated interface between the MR system control computer and the FUS wave generator. Two algorithms were used to regulate FUS power to maintain the focal point temperature at a desired level. Automatic control of FUS power level was demonstrated ex vivo at three target temperature levels (increase of 5 degrees C, 10 degrees C, and 30 degrees C above room temperature) during 30-minute hyperthermic periods. Preliminary in vivo results on rat leg muscle confirm that necrosis estimate, calculated on-line during FUS sonication, allows prediction of tissue damage. CONCLUSIONS. The feasibility of fully automatic FUS control based on MRI thermometry has been demonstrated.

  1. Development of a method for measuring femoral torsion using real-time ultrasound

    International Nuclear Information System (INIS)

    Hafiz, Eliza; Hiller, Claire E; Nightingale, E Jean; Eisenhuth, John P; Refshauge, Kathryn M; Nicholson, Leslie L; Clarke, Jillian L; Grimaldi, Alison

    2014-01-01

    Excessive femoral torsion has been associated with various musculoskeletal and neurological problems. To explore this relationship, it is essential to be able to measure femoral torsion in the clinic accurately. Computerized tomography (CT) and magnetic resonance imaging (MRI) are thought to provide the most accurate measurements but CT involves significant radiation exposure and MRI is expensive. The aim of this study was to design a method for measuring femoral torsion in the clinic, and to determine the reliability of this method. Details of design process, including construction of a jig, the protocol developed and the reliability of the method are presented. The protocol developed used ultrasound to image a ridge on the greater trochanter, and a customized jig placed on the femoral condyles as reference points. An inclinometer attached to the customized jig allowed quantification of the degree of femoral torsion. Measurements taken with this protocol had excellent intra- and inter-rater reliability (ICC 2,1  = 0.98 and 0.97, respectively). This method of measuring femoral torsion also permitted measurement of femoral torsion with a high degree of accuracy. This method is applicable to the research setting and, with minor adjustments, will be applicable to the clinical setting. (paper)

  2. Evaluation of focused ultrasound algorithms: Issues for reducing pre-focal heating and treatment time.

    Science.gov (United States)

    Yiannakou, Marinos; Trimikliniotis, Michael; Yiallouras, Christos; Damianou, Christakis

    2016-02-01

    Due to the heating in the pre-focal field the delay between successive movements in high intensity focused ultrasound (HIFU) are sometimes as long as 60s, resulting to treatment time in the order of 2-3h. Because there is generally a requirement to reduce treatment time, we were motivated to explore alternative transducer motion algorithms in order to reduce pre-focal heating and treatment time. A 1 MHz single element transducer with 4 cm diameter and 10 cm focal length was used. A simulation model was developed that estimates the temperature, thermal dose and lesion development in the pre-focal field. The simulated temperature history that was combined with the motion algorithms produced thermal maps in the pre-focal region. Polyacrylimde gel phantom was used to evaluate the induced pre-focal heating for each motion algorithm used, and also was used to assess the accuracy of the simulation model. Three out of the six algorithms having successive steps close to each other, exhibited severe heating in the pre-focal field. Minimal heating was produced with the algorithms having successive steps apart from each other (square, square spiral and random). The last three algorithms were improved further (with small cost in time), thus eliminating completely the pre-focal heating and reducing substantially the treatment time as compared to traditional algorithms. Out of the six algorithms, 3 were successful in eliminating the pre-focal heating completely. Because these 3 algorithms required no delay between successive movements (except in the last part of the motion), the treatment time was reduced by 93%. Therefore, it will be possible in the future, to achieve treatment time of focused ultrasound therapies shorter than 30 min. The rate of ablated volume achieved with one of the proposed algorithms was 71 cm(3)/h. The intention of this pilot study was to demonstrate that the navigation algorithms play the most important role in reducing pre-focal heating. By evaluating in

  3. Enhanced cavitation and heating of flowing polymer- and lipid-shelled microbubbles and phase-shift nanodroplets during focused ultrasound exposures

    Science.gov (United States)

    Zhang, Siyuan; Cui, Zhiwei; Li, Chong; Zhou, Fanyu; Zong, Yujin; Wang, Supin; Wan, Mingxi

    2017-03-01

    Cavitation and heating are the primary mechanisms of numerous therapeutic applications of ultrasound. Various encapsulated microbubbles (MBs) and phase-shift nanodroplets (NDs) have been used to enhance local cavitation and heating, creating interests in developing ultrasound therapy using these encapsulated MBs and NDs. This work compared the efficiency of flowing polymer- and lipid-shelled MBs and phase-shift NDs in cavitation and heating during focused ultrasound (FUS) exposures. Cavitation activity and temperature were investigated when the solution of polymer- and lipid-shelled MBs and NDs flowed through the vessel in a tissue-mimicking phantom with varying flow velocities when exposed to FUS at various acoustic power levels. The inertial cavitation dose (ICD) for the encapsulated MBs and NDs were higher than those for the saline. Temperature initially increased with increasing flow velocities of the encapsulated MBs, followed by a decrease of the temperature with increasing flow velocities when the velocity was much higher. Meanwhile, ICD showed a trend of increases with increasing flow velocity. For the phase-shift NDs, ICD after the first FUS exposure was lower than those after the second FUS exposure. For the encapsulated MBs, ICD after the first FUS exposure was higher than those after the second FUS exposure. Further studies are necessary to investigate the treatment efficiency of different encapsulated MBs and phase-shift NDs in cavitation and heating.

  4. Non-invasive and real-time passive acoustic mapping of ultrasound-mediated drug delivery

    International Nuclear Information System (INIS)

    Choi, James J; Carlisle, Robert C; Coviello, Christian; Coussios, Constantin-C; Seymour, Len

    2014-01-01

    New classes of biologically active materials, such as viruses, siRNA, antibodies and a wide range of engineered nanoparticles have emerged as potent agents for diagnosing and treating diseases, yet many of these agents fail because there is no effective route of delivery to their intended targets. Focused ultrasound and its ability to drive microbubble-seeded cavitation have been shown to facilitate drug delivery. However, cavitation is difficult to control temporally and spatially, making prediction of therapeutic outcomes deep in the body difficult. Here, we utilized passive acoustic mapping in vivo to understand how ultrasound parameters influence cavitation dynamics and to correlate spatial maps of cavitation to drug delivery. Focused ultrasound (center frequency: 0.5 MHz, peak-rarefactional pressure: 1.2 MPa, pulse length: 25 cycles or 50,000 cycles, pulse repetition interval: 0.02, 0.2, 1 or 3 s, number of pulses: 80 pulses) was applied to murine xenograft-model tumors in vivo during systemic injection of microbubbles with and without cavitation-sensitive liposomes or type 5 adenoviruses. Analysis of in vivo cavitation dynamics through several pulses revealed that cavitation was more efficiently produced at a lower pulse repetition frequency of 1 Hz than at 50 Hz. Within a pulse, inertial cavitation activity was shown to persist but reduced to 50% and 25% of its initial magnitude in 4.3 and 29.3 ms, respectively. Both through several pulses and within a pulse, the spatial distribution of cavitation was shown to change in time due to variations in microbubble distribution present in tumors. Finally, we demonstrated that the centroid of the mapped cavitation activity was within 1.33  ±  0.6 mm and 0.36 mm from the centroid location of drug release from liposomes and expression of the reporter gene encoded by the adenovirus, respectively. Thus passive acoustic mapping not only unraveled key mechanisms whereby a successful outcome is

  5. Comparisons of lesion detectability in ultrasound images acquired using time-shift compensation and spatial compounding.

    Science.gov (United States)

    Lacefield, James C; Pilkington, Wayne C; Waag, Robert C

    2004-12-01

    The effects of aberration, time-shift compensation, and spatial compounding on the discrimination of positive-contrast lesions in ultrasound b-scan images are investigated using a two-dimensional (2-D) array system and tissue-mimicking phantoms. Images were acquired within an 8.8 x 12-mm2 field of view centered on one of four statistically similar 4-mm diameter spherical lesions. Each lesion was imaged in four planes offset by successive 45 degree rotations about the central scan line. Images of the lesions were acquired using conventional geometric focusing through a water path, geometric focusing through a 35-mm thick distributed aberration phantom, and time-shift compensated transmit and receive focusing through the aberration phantom. The views of each lesion were averaged to form sets of water path, aberrated, and time-shift compensated 4:1 compound images and 16:1 compound images. The contrast ratio and detectability index of each image were computed to assess lesion differentiation. In the presence of aberration representative of breast or abdominal wall tissue, time-shift compensation provided statistically significant improvements of contrast ratio but did not consistently affect the detectability index, and spatial compounding significantly increased the detectability index but did not alter the contrast ratio. Time-shift compensation and spatial compounding thus provide complementary benefits to lesion detection.

  6. Contrast characteristics of barium preparations and the timing of exposure

    OpenAIRE

    渋谷, 光一; 中桐, 義忠; 東, 義晴; 杉田, 勝彦; 小橋, 高郎; 大倉, 保彦; 丹谷, 延義; 三上, 泰隆; 平木, 祥夫

    1995-01-01

    We studied the relationship between the contrast characteristics of barium suspension and timing of exposure. We poured several kinds of barium preparations on the phantom manufactured by ourselves, and took X-ray pictures continuously by a DSA system. We analyzed each of the characteris-tics of the contrast. The time which was reguired for the contrast to reach the peak (Contrast Peak Time ; CPT) was unrelated with the kind of barium preparations used. It depended on the viscosity of the con...

  7. Mediation analysis with time varying exposures and mediators.

    Science.gov (United States)

    VanderWeele, Tyler J; Tchetgen Tchetgen, Eric J

    2017-06-01

    In this paper we consider causal mediation analysis when exposures and mediators vary over time. We give non-parametric identification results, discuss parametric implementation, and also provide a weighting approach to direct and indirect effects based on combining the results of two marginal structural models. We also discuss how our results give rise to a causal interpretation of the effect estimates produced from longitudinal structural equation models. When there are time-varying confounders affected by prior exposure and mediator, natural direct and indirect effects are not identified. However, we define a randomized interventional analogue of natural direct and indirect effects that are identified in this setting. The formula that identifies these effects we refer to as the "mediational g-formula." When there is no mediation, the mediational g-formula reduces to Robins' regular g-formula for longitudinal data. When there are no time-varying confounders affected by prior exposure and mediator values, then the mediational g-formula reduces to a longitudinal version of Pearl's mediation formula. However, the mediational g-formula itself can accommodate both mediation and time-varying confounders and constitutes a general approach to mediation analysis with time-varying exposures and mediators.

  8. Female exposure to phthalates and time to pregnancy

    DEFF Research Database (Denmark)

    Thomsen, Anne Marie L.; Riis, Anders H.; Olsen, Jørn

    2017-01-01

    STUDY QUESTION: Is female exposure to phthalate metabolites associated with reduced fecundity, as estimated by prolonged time to pregnancy (TTP)? SUMMARY ANSWER: Female exposure to monoethyl phthalate (MEP) but not monobutyl phthalate (MBP), monobenzyl phthalate (MBzP) and monoethylhexyl phthalate...... with prospective data based on 229 women from a Danish cohort of 430 first pregnancy planning couples enrolled in 1992-1994. In 2009, urinary analyses of phthalate metabolites were performed on stored urine samples from this cohort. PARTICIPANTS/MATERIALS, SETTING AND METHODS: We analyzed MEP, MBP, MBzP and MEHP...... to estimate fecundability ratios (FRs) and 95% CI in relation to the average urine metabolite concentration exposure level, controlled for age and BMI, and the time-varying variables smoking and alcohol. MAIN RESULT AND ROLE OF CHANCE: Urinary concentration of MEP was associated with a decreased fecundity...

  9. interactive effect of cowpea variety, dose and exposure time

    African Journals Online (AJOL)

    ACSS

    variety (V), exposure time (T) and dose (D) on the tolerance of C. maculatus to both plant materials. The effect ... laboratories and institutions of higher education in several West .... Each value is the mean±S.E of 20 cowpea seeds. Means ...

  10. Real-Time Ultrasound-Guided Catheter Navigation for Approaching Deep-Seated Brain Lesions: Role of Intraoperative Neurosonography with and without Fusion with Magnetic Resonance Imaging.

    Science.gov (United States)

    Manjila, Sunil; Karhade, Aditya; Phi, Ji Hoon; Scott, R Michael; Smith, Edward R

    2017-01-01

    Brain shift during the exposure of cranial lesions may reduce the accuracy of frameless stereotaxy. We describe a rapid, safe, and effective method to approach deep-seated brain lesions using real-time intraoperative ultrasound placement of a catheter to mark the dissection trajectory to the lesion. With Institutional Review Board approval, we retrospectively reviewed the radiographic, pathologic, and intraoperative data of 11 pediatric patients who underwent excision of 12 lesions by means of this technique. Full data sets were available for 12 lesions in 11 patients. Ten lesions were tumors and 2 were cavernous malformations. Lesion locations included the thalamus (n = 4), trigone (n = 3), mesial temporal lobe (n = 3), and deep white matter (n = 2). Catheter placement was successful in all patients, and the median time required for the procedure was 3 min (range 2-5 min). There were no complications related to catheter placement. The median diameter of surgical corridors on postresection magnetic resonance imaging was 6.6 mm (range 3.0-12.1 mm). Use of real-time ultrasound guidance to place a catheter to aid in the dissection to reach a deep-seated brain lesion provides advantages complementary to existing techniques, such as frameless stereotaxy. The catheter insertion technique described here provides a quick, accurate, and safe method for reaching deep-seated lesions. © 2017 S. Karger AG, Basel.

  11. [Doppler ultrasound evaluation of aortic insufficiency using half-pressure time. Absence of arterial rigidity influence].

    Science.gov (United States)

    Kalotka-Bratek, H; Drobinski, G; Klimczak, K; Busquet, P; Fraysse, J B; Bejean-Lebuisson, A; Grosgogeat, Y

    1989-02-01

    In 20 patients with pure aortic regurgitation we studied the relationship between the severity of regurgitation, as assessed haemodynamically by the percentage of leakage (%L), and the half-pressure (T 1/2 P) and half-velocity (T 1/2 V) times, as obtained from doppler aortic blood velocity curves, taking into account the rigidity of the systemic vascular circuit characterized by the pressure wave propagation velocity (PWPV). The systemic arterial circuit was supple in 14 patients (PWPV less than 7.5 m/sec) and rigid in 6 patients (PWPV greater than 7.5 m/sec). The regression slopes between %L and T 1/2 P and between %L and T 1/2 V were calculated with their confidence limits in the 14 patients with supple arteries. The 6 patients with rigid arteries fitted into this nomogram, thus demonstrating that systemic arterial rigidity makes no difference in the relationship between %L and doppler indices. The half-velocity and half-pressure times measured by doppler ultrasound were acquired from a velocity signal directly determined by the aortic regurgitation, without any detectable effect of vascular circuit rigidity. Being equivalent by nature to the signal decrease time constant, they are independent of the absolute protodiastolic value of diastolic pressure gradient or blood flow velocity. For this reason these two doppler parameters are reliable to evaluate the severity of aortic regurgitation.

  12. Combining endoscopic ultrasound with Time-Of-Flight PET: The EndoTOFPET-US Project

    CERN Document Server

    Frisch, Benjamin

    2013-01-01

    The EndoTOFPET-US collaboration develops a multimodal imaging technique for endoscopic exams of the pancreas or the prostate. It combines the benefits of high resolution metabolic imaging with Time-Of-Flight Positron Emission Tomography (TOF PET) and anatomical imaging with ultrasound (US). EndoTOFPET-US consists of a PET head extension for a commercial US endoscope and a PET plate outside the body in coincidence with the head. The high level of miniaturization and integration creates challenges in fields such as scintillating crystals, ultra-fast photo-detection, highly integrated electronics, system integration and image reconstruction. Amongst the developments, fast scintillators as well as fast and compact digital SiPMs with single SPAD readout are used to obtain the best coincidence time resolution (CTR). Highly integrated ASICs and DAQ electronics contribute to the timing performances of EndoTOFPET. In view of the targeted resolution of around 1 mm in the reconstructed image, we present a prototype dete...

  13. Prostate Ultrasound

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Ultrasound - Prostate Ultrasound of the prostate uses sound waves to ... Ultrasound Imaging? What is Ultrasound Imaging of the Prostate? Ultrasound is safe and painless, and produces pictures ...

  14. Ultrasound-based measurement of liquid-layer thickness: A novel time-domain approach

    Science.gov (United States)

    Praher, Bernhard; Steinbichler, Georg

    2017-01-01

    Measuring the thickness of a thin liquid layer between two solid materials is important when the adequate separation of metallic parts by a lubricant film (e.g., in bearings or mechanical seals) is to be assessed. The challenge in using ultrasound-based systems for such measurements is that the signal from the liquid layer is a superposition of multiple reflections. We have developed an algorithm for reconstructing this superimposed signal in the time domain. By comparing simulated and measured signals, the time-of-flight of the ultrasonic pulse in a layer can be estimated. With the longitudinal sound velocity known, the layer thickness can then be calculated. In laboratory measurements, we validate successfully (maximum relative error 4.9%) our algorithm for layer thicknesses ranging from 30 μm to 200 μm. Furthermore, we tested our method in the high-temperature environment of polymer processing by measuring the clearance between screw and barrel in the plasticisation unit of an injection moulding machine. The results of such measurements can indicate (i) the wear status of the tribo-mechanical screw-barrel system and (ii) unsuitable process conditions.

  15. Visual detectability of elastic contrast in real-time ultrasound images

    Science.gov (United States)

    Miller, Naomi R.; Bamber, Jeffery C.; Doyley, Marvin M.; Leach, Martin O.

    1997-04-01

    Elasticity imaging (EI) has recently been proposed as a technique for imaging the mechanical properties of soft tissue. However, dynamic features, known as compressibility and mobility, are already employed to distinguish between different tissue types in ultrasound breast examination. This method, which involves the subjective interpretation of tissue motion seen in real-time B-mode images during palpation, is hereafter referred to as differential motion imaging (DMI). The purpose of this study was to develop the methodology required to perform a series of perception experiments to measure elastic lesion detectability by means of DMI and to obtain preliminary results for elastic contrast thresholds for different lesion sizes. Simulated sequences of real-time B-scans of tissue moving in response to an applied force were generated. A two-alternative forced choice (2-AFC) experiment was conducted and the measured contrast thresholds were compared with published results for lesions detected by EI. Although the trained observer was found to be quite skilled at the task of differential motion perception, it would appear that lesion detectability is improved when motion information is detected by computer processing and converted to gray scale before presentation to the observer. In particular, for lesions containing fewer than eight speckle cells, a signal detection rate of 100% could not be achieved even when the elastic contrast was very high.

  16. Journey-time exposure to particulate air pollution

    Science.gov (United States)

    Gulliver, John; Briggs, David J.

    Journey-time exposures to particulate air pollution were investigated in Leicester, UK, between January and March 2005. Samples of TSP, PM 10, PM 2.5, and PM 1 were simultaneously collected using light scattering devices whilst journeys were made by walking an in-car. Over a period of two months, 33 pairs of walking and in-car measurements were collected along two circular routes. Average exposures while walking were seen to be higher than those found in-car for each of the particle fractions: average walking to in-car ratios were 1.2 (± 0.6), 1.5 (± 0.6), 1.3 (± 0.6), and 1.4 (± 0.6) μg m -3 for coarse (TSP-PM 10), intermediate (PM 10-PM 2.5), fine (PM 2.5-PM 1), and very fine particles (PM 1), respectively. Correlations between walking and in-car exposures were seen to be weak for coarse particles ( r=0.10, p=0.58), moderate for the intermediate particles ( r=0.49, pcar exposures were 25% higher than the same fixed-site monitor. Particles with an aerodynamic diameter of less than 2.5 μm were seen to be highly correlated between walking and in-car particle exposures and a rural fixed-site monitor about 30 km south of Leicester.

  17. Treatment time reduction for large thermal lesions by using a multiple 1D ultrasound phased array system

    International Nuclear Information System (INIS)

    Liu, H.-L.; Chen, Y.-Y.; Yen, J.-Y.; Lin, W.-L.

    2003-01-01

    To generate large thermal lesions in ultrasound thermal therapy, cooling intermissions are usually introduced during the treatment to prevent near-field heating, which leads to a long treatment time. A possible strategy to shorten the total treatment time is to eliminate the cooling intermissions. In this study, the two methods, power optimization and acoustic window enlargement, for reducing power accumulation in the near field are combined to investigate the feasibility of continuously heating a large target region (maximally 3.2 x 3.2 x 3.2 cm 3 ). A multiple 1D ultrasound phased array system generates the foci to scan the target region. Simulations show that the target region can be successfully heated without cooling and no near-field heating occurs. Moreover, due to the fact that there is no cooling time during the heating sessions, the total treatment time is significantly reduced to only several minutes, compared to the existing several hours

  18. Real-time elastography in autonomously functioning thyroid nodules: relationship with TSH levels, scintigraphy, and ultrasound patterns.

    Science.gov (United States)

    Trimboli, Pierpaolo; Paone, Gaetano; Zatelli, Maria Chiara; Ceriani, Luca; Giovanella, Luca

    2017-12-01

    Real-time elastography has been proposed to increase the sensitivity of ultrasound and improve the detection of thyroid nodules at risk of malignancy. To date sparse data on real-time elastography assessment of autonomously functioning thyroid nodules exist. Here, we investigated the potential role of real-time elastography in autonomously functioning thyroid nodule assessment. Specifically, the correlation between serum hormones and real-time elastography score, as well as other clinical and ultrasound features, was analyzed. Patients with autonomously functioning thyroid nodule identified by I-123 scintigraphy from September 2015 to July 2016 and undergoing ultrasound, real-time elastography, and thyroid function evaluation were selected. All autonomously functioning thyroid nodule were classified as RTE I (prevalence of red or green color with blue in up to 25% of the nodule area), RTE II (blue in 25-75%), or RTE III (blue in more than 75%). The association between suppressed thyroid stimulating hormone and patient's age, nodule's size, ultrasound presentation, and real-time elastography scoring was analyzed by Odds Ratio in univariate fashion and multivariate model. A number of 47 subjects with single autonomously functioning thyroid nodule were enrolled. Median age of 63 years, median size of 2.0 cm, and suppressed thyroid stimulating hormone levels in 32% of cases were found. Those nodules classified by ultrasound at high risk underwent fine-needle aspiration cytology and cancer was excluded. At real-time elastography evaluation, a 45% of autonomously functioning thyroid nodule had a hard appearance (RTE III) and had thyroid stimulating hormone significantly lower than the other (p < 0.0001). A model of multivariate logistic regression including nodule's size, ultrasound characteristics, and elastographic presentation showed that only RTE III was significantly associated with suppressed thyroid stimulating hormone (Odds Ratio of 50). Autonomously

  19. Comparative assessments of the effects of alcohol exposure on fetal brain development using optical coherence tomography and ultrasound imaging

    Science.gov (United States)

    Sudheendran, Narendran; Bake, Shameena; Miranda, Rajesh C.; Larin, Kirill V.

    2013-02-01

    The developing fetal brain is vulnerable to a variety of environmental agents including maternal ethanol consumption. Preclinical studies on the development and amelioration of fetal teratology would be significantly facilitated by the application of high resolution imaging technologies like optical coherence tomography (OCT) and high-frequency ultrasound (US). This study investigates the ability of these imaging technologies to measure the effects of maternal ethanol exposure on brain development, ex vivo, in fetal mice. Pregnant mice at gestational day 12.5 were administered ethanol (3 g/Kg b.wt.) or water by intragastric gavage, twice daily for three consecutive days. On gestational day 14.5, fetuses were collected and imaged. Three-dimensional images of the mice fetus brains were obtained by OCT and high-resolution US, and the volumes of the left and right ventricles of the brain were measured. Ethanol-exposed fetuses exhibited a statistically significant, 2-fold increase in average left and right ventricular volumes compared with the ventricular volume of control fetuses, with OCT-derived measures of 0.38 and 0.18 mm3, respectively, whereas the boundaries of the fetal mouse lateral ventricles were not clearly definable with US imaging. Our results indicate that OCT is a useful technology for assessing ventriculomegaly accompanying alcohol-induced developmental delay. This study clearly demonstrated advantages of using OCT for quantitative assessment of embryonic development compared with US imaging.

  20. [Ultrasound guided percutaneous nephrolithotripsy].

    Science.gov (United States)

    Guliev, B G

    2014-01-01

    The study was aimed to the evaluation of the effectiveness and results of ultrasound guided percutaneous nephrolithotripsy (PNL) for the treatment of patients with large stones in renal pelvis. The results of PNL in 138 patients who underwent surgery for kidney stones from 2011 to 2013 were analyzed. Seventy patients (Group 1) underwent surgery with combined ultrasound and radiological guidance, and 68 patients (Group 2)--only with ultrasound guidance. The study included patients with large renal pelvic stones larger than 2.2 cm, requiring the formation of a single laparoscopic approach. Using the comparative analysis, the timing of surgery, the number of intra- and postoperative complications, blood loss and length of stay were evaluated. Percutaneous access was successfully performed in all patients. Postoperative complications (exacerbation of chronic pyelonephritis, gross hematuria) were observed in 14.3% of patients in Group 1 and in 14.7% of patients in Group 2. Bleeding requiring blood transfusion, and injuries of adjacent organs were not registered. Efficacy of PNL in the Group 1 was 95.7%; 3 (4.3%) patients required additional interventions. In Group 2, the effectiveness of PNL was 94.1%, 4 (5.9%) patients additionally underwent extracorporeal lithotripsy. There were no significant differences in the effectiveness of PNL, the volume of blood loss and duration of hospitalization. Ultrasound guided PNL can be performed in large pelvic stones and sufficient expansion of renal cavities, thus reducing radiation exposure of patients and medical staff.

  1. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z General Ultrasound Ultrasound ... computer or television monitor. The image is created based on the amplitude (loudness), frequency (pitch) and time ...

  2. Real-time Monitoring of High Intensity Focused Ultrasound (HIFU) Ablation of In Vitro Canine Livers Using Harmonic Motion Imaging for Focused Ultrasound (HMIFU).

    Science.gov (United States)

    Grondin, Julien; Payen, Thomas; Wang, Shutao; Konofagou, Elisa E

    2015-11-03

    Harmonic Motion Imaging for Focused Ultrasound (HMIFU) is a technique that can perform and monitor high-intensity focused ultrasound (HIFU) ablation. An oscillatory motion is generated at the focus of a 93-element and 4.5 MHz center frequency HIFU transducer by applying a 25 Hz amplitude-modulated signal using a function generator. A 64-element and 2.5 MHz imaging transducer with 68kPa peak pressure is confocally placed at the center of the HIFU transducer to acquire the radio-frequency (RF) channel data. In this protocol, real-time monitoring of thermal ablation using HIFU with an acoustic power of 7 W on canine livers in vitro is described. HIFU treatment is applied on the tissue during 2 min and the ablated region is imaged in real-time using diverging or plane wave imaging up to 1,000 frames/second. The matrix of RF channel data is multiplied by a sparse matrix for image reconstruction. The reconstructed field of view is of 90° for diverging wave and 20 mm for plane wave imaging and the data are sampled at 80 MHz. The reconstruction is performed on a Graphical Processing Unit (GPU) in order to image in real-time at a 4.5 display frame rate. 1-D normalized cross-correlation of the reconstructed RF data is used to estimate axial displacements in the focal region. The magnitude of the peak-to-peak displacement at the focal depth decreases during the thermal ablation which denotes stiffening of the tissue due to the formation of a lesion. The displacement signal-to-noise ratio (SNRd) at the focal area for plane wave was 1.4 times higher than for diverging wave showing that plane wave imaging appears to produce better displacement maps quality for HMIFU than diverging wave imaging.

  3. Comparison of active-set method deconvolution and matched-filtering for derivation of an ultrasound transit time spectrum

    International Nuclear Information System (INIS)

    Wille, M-L; Langton, C M; Zapf, M; Ruiter, N V; Gemmeke, H

    2015-01-01

    The quality of ultrasound computed tomography imaging is primarily determined by the accuracy of ultrasound transit time measurement. A major problem in analysis is the overlap of signals making it difficult to detect the correct transit time. The current standard is to apply a matched-filtering approach to the input and output signals. This study compares the matched-filtering technique with active set deconvolution to derive a transit time spectrum from a coded excitation chirp signal and the measured output signal. The ultrasound wave travels in a direct and a reflected path to the receiver, resulting in an overlap in the recorded output signal. The matched-filtering and deconvolution techniques were applied to determine the transit times associated with the two signal paths. Both techniques were able to detect the two different transit times; while matched-filtering has a better accuracy (0.13 μs versus 0.18 μs standard deviations), deconvolution has a 3.5 times improved side-lobe to main-lobe ratio. A higher side-lobe suppression is important to further improve image fidelity. These results suggest that a future combination of both techniques would provide improved signal detection and hence improved image fidelity. (note)

  4. Transabdominal ultrasound measurement of rectal diameter is dependent on time to defecation in constipated children

    DEFF Research Database (Denmark)

    Modin, Line; Dalby, Kasper; Walsted, Anne-Mette

    2015-01-01

    AIM: To study whether diurnal variations and time in relation to defecation has to be taken into account when measurements of rectal diameter are used to determine faecal impaction in constipated children. METHODS: Repeated ultrasound measures of rectal diameter were performed in 28 children (14...... constipated/14 healthy, aged between 4 and 12 years) every third hour during 24 h. After defecation, three additional scans were performed at 1-h intervals. RESULTS: No diurnal variation in rectal diameter was found in the healthy group. In the constipated group, mean rectal diameter was significantly larger...... at 2 pm (P = 0.038) and 5 pm (P = 0.006). There were significant differences between rectal diameter in the healthy group and the constipated group at 2 pm (P = 0.016) and 5 pm (P = 0.027). When we omitted the rectal diameter of five constipated children who had their first bowel movement after 5 pm...

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

    International Nuclear Information System (INIS)

    Brent, R.L.

    1989-01-01

    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

  6. Hybrid Photoacoustic/Ultrasound Tomograph for Real-Time Finger Imaging.

    Science.gov (United States)

    Oeri, Milan; Bost, Wolfgang; Sénégond, Nicolas; Tretbar, Steffen; Fournelle, Marc

    2017-10-01

    We report a target-enclosing, hybrid tomograph with a total of 768 elements based on capacitive micromachined ultrasound transducer technology and providing fast, high-resolution 2-D/3-D photoacoustic and ultrasound tomography tailored to finger imaging. A freely programmable ultrasound beamforming platform sampling data at 80 MHz was developed to realize plane wave transmission under multiple angles. A multiplexing unit enables the connection and control of a large number of elements. Fast image reconstruction is provided by GPU processing. The tomograph is composed of four independent and fully automated movable arc-shaped transducers, allowing imaging of all three finger joints. The system benefits from photoacoustics, yielding high optical contrast and enabling visualization of finger vascularization, and ultrasound provides morphologic information on joints and surrounding tissue. A diode-pumped, Q-switched Nd:YAG laser and an optical parametric oscillator are used to broaden the spectrum of emitted wavelengths to provide multispectral imaging. Custom-made optical fiber bundles enable illumination of the region of interest in the plane of acoustic detection. Precision in positioning of the probe in motion is ensured by use of a motor-driven guide slide. The current position of the probe is encoded by the stage and used to relate ultrasound and photoacoustic signals to the corresponding region of interest of the suspicious finger joint. The system is characterized in phantoms and a healthy human finger in vivo. The results obtained promise to provide new opportunities in finger diagnostics and establish photoacoustic/ultrasound-tomography in medical routine. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  7. The effect of two-injection ethanol sclerotherapy with 5 minute duration of exposure time in simple renal cysts

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Eun; Cho, Jae Ho [Dept. of Radiology, College of Medicine, Yeungnam University, Daegu (Korea, Republic of)

    2017-08-15

    To evaluate the results of two-injection ethanol sclerotherapy in simple renal cysts performed with 5-minute ethanol exposure time. We retrospectively reviewed 30 renal cysts in 30 patients treated by ethanol sclerotherapy between November 2002 and October 2015. Under ultrasound guidance, the renal cyst was punctured and a 7 Fr pigtail catheter was inserted, and then complete aspiration of the cystic fluid was performed. Then, 99.9% ethanol in a quantity amounting to 1/3–1/2 of the aspirated volume was infused into the cyst and it was immediately removed. The same amount of ethanol was re-infused and removed after 5 minutes. Follow-up examination was performed using ultrasound or CT images at least 3 months after the procedure and pre- and post-treatment cyst volumes were estimated. The therapeutic response was classified as either complete success (volume reduction, ≥ 95%), partial success (volume reduction, 50–95%), or failure (volume reduction, < 50%) based on the volume reduction rate. The average volume reduction rate was 96.3%. The rates of complete success, partial success and failure were 80% (n = 24), 20% (n = 6), and 0% (n = 0), respectively. There was no complication except for minor flank pain. Two-injection ethanol sclerotherapy with 5-minute exposure time represents a simple and effective treatment for simple renal cysts.

  8. Prostate Ultrasound

    Medline Plus

    Full Text Available ... through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Prostate ultrasound, also called transrectal ultrasound, provides ...

  9. Preoperative magnetic resonance and intraoperative ultrasound fusion imaging for real-time neuronavigation in brain tumor surgery.

    Science.gov (United States)

    Prada, F; Del Bene, M; Mattei, L; Lodigiani, L; DeBeni, S; Kolev, V; Vetrano, I; Solbiati, L; Sakas, G; DiMeco, F

    2015-04-01

    Brain shift and tissue deformation during surgery for intracranial lesions are the main actual limitations of neuro-navigation (NN), which currently relies mainly on preoperative imaging. Ultrasound (US), being a real-time imaging modality, is becoming progressively more widespread during neurosurgical procedures, but most neurosurgeons, trained on axial computed tomography (CT) and magnetic resonance imaging (MRI) slices, lack specific US training and have difficulties recognizing anatomic structures with the same confidence as in preoperative imaging. Therefore real-time intraoperative fusion imaging (FI) between preoperative imaging and intraoperative ultrasound (ioUS) for virtual navigation (VN) is highly desirable. We describe our procedure for real-time navigation during surgery for different cerebral lesions. We performed fusion imaging with virtual navigation for patients undergoing surgery for brain lesion removal using an ultrasound-based real-time neuro-navigation system that fuses intraoperative cerebral ultrasound with preoperative MRI and simultaneously displays an MRI slice coplanar to an ioUS image. 58 patients underwent surgery at our institution for intracranial lesion removal with image guidance using a US system equipped with fusion imaging for neuro-navigation. In all cases the initial (external) registration error obtained by the corresponding anatomical landmark procedure was below 2 mm and the craniotomy was correctly placed. The transdural window gave satisfactory US image quality and the lesion was always detectable and measurable on both axes. Brain shift/deformation correction has been successfully employed in 42 cases to restore the co-registration during surgery. The accuracy of ioUS/MRI fusion/overlapping was confirmed intraoperatively under direct visualization of anatomic landmarks and the error was surgery and is less expensive and time-consuming than other intraoperative imaging techniques, offering high precision and

  10. Ultrasound contrast agent imaging: Real-time imaging of the superharmonics

    Energy Technology Data Exchange (ETDEWEB)

    Peruzzini, D.; Viti, J. [MSD lab, Department of Information Engineering, Univ of Florence, Via S.Marta, 3, 50139 Firenze (Italy); Erasmus MC, ’s-Gravendijkwal 230, Faculty Building, Ee 2302, 3015 CE Rotterdam (Netherlands); Tortoli, P. [MSD lab, Department of Information Engineering, Univ of Florence, Via S.Marta, 3, 50139 Firenze (Italy); Verweij, M. D. [Acoustical Wavefield Imaging, ImPhys, Delft Univ Technology, van der Waalsweg 8, 2628 CH Delft (Netherlands); Jong, N. de; Vos, H. J., E-mail: h.vos@erasmusmc.nl [Erasmus MC, ’s-Gravendijkwal 230, Faculty Building, Ee 2302, 3015 CE Rotterdam (Netherlands); Acoustical Wavefield Imaging, ImPhys, Delft Univ Technology, van der Waalsweg 8, 2628 CH Delft (Netherlands)

    2015-10-28

    Currently, in medical ultrasound contrast agent (UCA) imaging the second harmonic scattering of the microbubbles is regularly used. This scattering is in competition with the signal that is caused by nonlinear wave propagation in tissue. It was reported that UCA imaging based on the third or higher harmonics, i.e. “superharmonic” imaging, shows better contrast. However, the superharmonic scattering has a lower signal level compared to e.g. second harmonic signals. This study investigates the contrast-to-tissue ratio (CTR) and signal to noise ratio (SNR) of superharmonic UCA scattering in a tissue/vessel mimicking phantom using a real-time clinical scanner. Numerical simulations were performed to estimate the level of harmonics generated by the microbubbles. Data were acquired with a custom built dual-frequency cardiac phased array probe. Fundamental real-time images were produced while beam formed radiofrequency (RF) data was stored for further offline processing. The phantom consisted of a cavity filled with UCA surrounded by tissue mimicking material. The acoustic pressure in the cavity of the phantom was 110 kPa (MI = 0.11) ensuring non-destructivity of UCA. After processing of the acquired data from the phantom, the UCA-filled cavity could be clearly observed in the images, while tissue signals were suppressed at or below the noise floor. The measured CTR values were 36 dB, >38 dB, and >32 dB, for the second, third, and fourth harmonic respectively, which were in agreement with those reported earlier for preliminary contrast superharmonic imaging. The single frame SNR values (in which ‘signal’ denotes the signal level from the UCA area) were 23 dB, 18 dB, and 11 dB, respectively. This indicates that noise, and not the tissue signal, is the limiting factor for the UCA detection when using the superharmonics in nondestructive mode.

  11. [Solar exposure time for sunburn in Mexican population].

    Science.gov (United States)

    Castanedo Cázares, Juan Pablo; Torres Álvarez, Bertha; Sobrevilla Ondarza, Salvador; Ehnis Pérez, Adriana; Gordillo Moscoso, Antonio

    2012-01-01

    THe minimal erythemal dose (MED) quantifies an individual's sensitivity to UV radiation (UVR). To estimate it in our population and establish the time of exposure inducing it during daily activities would allow us to calculate risk intervals. From 2005-2012, the UV solar radiation was measured with terrestrial radiometry and compared to public UV index (UVI). We determined the MED in 90 individuals with the prevalent phototypes in Mexico (III, IV, V), and estimated the time needed for the development of sunburn. The average MED for phototype III was 39 (IC 95%: 35-42) mJ/cm2, for IV 48 (IC 95%:42-53) mJ/cm2, and for V was 84 (IC 95%:75-92) mJ/cm2 (ANOVA, p ≤ 0.001). Approximately, 80% of the daily UVR was accumulated between 10:00-16:00 h, and 77% of the annual UV dose is received between March-October. The public UVI had a high correlation with the one quantified at terrestrial level (r = 0.89; p ≤ 0.001). Mexico receives continuously high levels of UVR. Phototype III will present sunburn after 22-33 min in a summer day, while phototype V will require over one hour of exposure. This last group is at risk of chronic exposure without considering consequences.

  12. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... the patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... by a computer, which in turn creates a real-time picture on the monitor. One or more frames ...

  13. Low power laser generated ultrasound: Signal processing for time domain data acquisition

    International Nuclear Information System (INIS)

    Cleary, A; Thursby, G; McKee, C; Armstrong, I; Culshaw, B; Veres, I; Pierce, S G

    2011-01-01

    The use of low power modulated laser diode systems has previously been established as a suitable method for non-destructive laser generation of ultrasound. Using a quasi-continuous optical excitation amplified by an erbium-doped fibre amplifier (EDFA) allows flexible generation of ultrasonic waves, offering control of further parameters such as the frequency content or signal shape. In addition, pseudo-random binary sequences (PRBS) can be used to improve the detected impulse response. Here we compare two sequences, the m-sequence and the Golay code, and discuss the advantages and practical limits of their application with laser diode based optical excitation of ultrasound.

  14. Rapidly-steered single-element ultrasound for real-time volumetric imaging and guidance

    Science.gov (United States)

    Stauber, Mark; Western, Craig; Solek, Roman; Salisbury, Kenneth; Hristov, Dmitre; Schlosser, Jeffrey

    2016-03-01

    Volumetric ultrasound (US) imaging has the potential to provide real-time anatomical imaging with high soft-tissue contrast in a variety of diagnostic and therapeutic guidance applications. However, existing volumetric US machines utilize "wobbling" linear phased array or matrix phased array transducers which are costly to manufacture and necessitate bulky external processing units. To drastically reduce cost, improve portability, and reduce footprint, we propose a rapidly-steered single-element volumetric US imaging system. In this paper we explore the feasibility of this system with a proof-of-concept single-element volumetric US imaging device. The device uses a multi-directional raster-scan technique to generate a series of two-dimensional (2D) slices that were reconstructed into three-dimensional (3D) volumes. At 15 cm depth, 90° lateral field of view (FOV), and 20° elevation FOV, the device produced 20-slice volumes at a rate of 0.8 Hz. Imaging performance was evaluated using an US phantom. Spatial resolution was 2.0 mm, 4.7 mm, and 5.0 mm in the axial, lateral, and elevational directions at 7.5 cm. Relative motion of phantom targets were automatically tracked within US volumes with a mean error of -0.3+/-0.3 mm, -0.3+/-0.3 mm, and -0.1+/-0.5 mm in the axial, lateral, and elevational directions, respectively. The device exhibited a mean spatial distortion error of 0.3+/-0.9 mm, 0.4+/-0.7 mm, and -0.3+/-1.9 in the axial, lateral, and elevational directions. With a production cost near $1000, the performance characteristics of the proposed system make it an ideal candidate for diagnostic and image-guided therapy applications where form factor and low cost are paramount.

  15. Computer-assisted assessment of ultrasound real-time elastography: initial experience in 145 breast lesions.

    Science.gov (United States)

    Zhang, Xue; Xiao, Yang; Zeng, Jie; Qiu, Weibao; Qian, Ming; Wang, Congzhi; Zheng, Rongqin; Zheng, Hairong

    2014-01-01

    To develop and evaluate a computer-assisted method of quantifying five-point elasticity scoring system based on ultrasound real-time elastography (RTE), for classifying benign and malignant breast lesions, with pathologic results as the reference standard. Conventional ultrasonography (US) and RTE images of 145 breast lesions (67 malignant, 78 benign) were performed in this study. Each lesion was automatically contoured on the B-mode image by the level set method and mapped on the RTE image. The relative elasticity value of each pixel was reconstructed and classified into hard or soft by the fuzzy c-means clustering method. According to the hardness degree inside lesion and its surrounding tissue, the elasticity score of the RTE image was computed in an automatic way. Visual assessments of the radiologists were used for comparing the diagnostic performance. Histopathologic examination was used as the reference standard. The Student's t test and receiver operating characteristic (ROC) curve analysis were performed for statistical analysis. Considering score 4 or higher as test positive for malignancy, the diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 93.8% (136/145), 92.5% (62/67), 94.9% (74/78), 93.9% (62/66), and 93.7% (74/79) for the computer-assisted scheme, and 89.7% (130/145), 85.1% (57/67), 93.6% (73/78), 92.0% (57/62), and 88.0% (73/83) for manual assessment. Area under ROC curve (Az value) for the proposed method was higher than the Az value for visual assessment (0.96 vs. 0.93). Computer-assisted quantification of classical five-point scoring system can significantly eliminate the interobserver variability and thereby improve the diagnostic confidence of classifying the breast lesions to avoid unnecessary biopsy. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  16. Computer-assisted assessment of ultrasound real-time elastography: Initial experience in 145 breast lesions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xue; Xiao, Yang [Shenzhen Key Lab for Molecular Imaging, Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen (China); Zeng, Jie [Department of Medical Ultrasonics, Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou (China); Qiu, Weibao; Qian, Ming; Wang, Congzhi [Shenzhen Key Lab for Molecular Imaging, Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen (China); Zheng, Rongqin, E-mail: zhengronggin@hotmail.com [Department of Medical Ultrasonics, Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou (China); Zheng, Hairong, E-mail: hr.zheng@siat.ac.cn [Shenzhen Key Lab for Molecular Imaging, Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen (China)

    2014-01-15

    Purpose: To develop and evaluate a computer-assisted method of quantifying five-point elasticity scoring system based on ultrasound real-time elastography (RTE), for classifying benign and malignant breast lesions, with pathologic results as the reference standard. Materials and methods: Conventional ultrasonography (US) and RTE images of 145 breast lesions (67 malignant, 78 benign) were performed in this study. Each lesion was automatically contoured on the B-mode image by the level set method and mapped on the RTE image. The relative elasticity value of each pixel was reconstructed and classified into hard or soft by the fuzzy c-means clustering method. According to the hardness degree inside lesion and its surrounding tissue, the elasticity score of the RTE image was computed in an automatic way. Visual assessments of the radiologists were used for comparing the diagnostic performance. Histopathologic examination was used as the reference standard. The Student's t test and receiver operating characteristic (ROC) curve analysis were performed for statistical analysis. Results: Considering score 4 or higher as test positive for malignancy, the diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 93.8% (136/145), 92.5% (62/67), 94.9% (74/78), 93.9% (62/66), and 93.7% (74/79) for the computer-assisted scheme, and 89.7% (130/145), 85.1% (57/67), 93.6% (73/78), 92.0% (57/62), and 88.0% (73/83) for manual assessment. Area under ROC curve (A{sub z} value) for the proposed method was higher than the A{sub z} value for visual assessment (0.96 vs. 0.93). Conclusion: Computer-assisted quantification of classical five-point scoring system can significantly eliminate the interobserver variability and thereby improve the diagnostic confidence of classifying the breast lesions to avoid unnecessary biopsy.

  17. Reproducibility of phantom-based quality assurance parameters in real-time ultrasound imaging.

    Science.gov (United States)

    Sipilä, Outi; Blomqvist, Päivi; Jauhiainen, Mervi; Kilpeläinen, Tiina; Malaska, Paula; Mannila, Vilma; Vinnurva-Jussila, Tuula; Virsula, Sari

    2011-07-01

    In a large radiological center, the ultrasound (US) quality assurance (QA) program involves several professionals. Although the operator and the parameters utilized can contribute to the results, the selected QA parameters should still reflect the quality of the US scanner, not the measuring process. To evaluate the reproducibility of recommended phantom-based US QA parameters in a realistic environment. Six sonographers measured six high-end US scanners with 20 transducers using a general purpose phantom. Every transducer was measured altogether seven times, using one frequency per transducer. The QA parameters studied were homogeneity, visualization depth, vertical and horizontal distance measurements, axial and lateral resolution, and the correct visibility of anechoic and high-contrast masses. The evaluation of the homogeneity was based on visual observations. Inter-observer interquartile ranges were computed for the grading of the masses. For the other QA parameters, the mean inter- and intra-observer coefficients of variation (CoV) were calculated. In addition, the symmetry of the reverberations when imaging air with a clean transducer was checked. The mean inter-observer CoVs were: visualization depth 11 ± 4%, vertical distance 1.7 ± 0.4%, horizontal distance 1.4 ± 0.6%, axial resolution 22 ± 7%, and lateral resolution 16 ± 8%. The mean intra-observer values were about half of these values with similar standard deviations. The visual evaluation of the homogeneity and the symmetry of the reverberations produced false-positive findings in 5% of the cases, but were found useful in detecting a defective transducer. The grading of the masses had mean interquartile ranges of 20-30% of the grading scale. The inter-observer variability in measuring phantom-based QA parameters can be relatively high. This should be considered when implementing a phantom-based QA protocol and evaluating the results.

  18. Prostate Ultrasound

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    Full Text Available ... ultrasound or with a rectal examination, an ultrasound-guided biopsy can be performed. This procedure involves advancing ... of the Prostate) Prostate Cancer Ultrasound- and MRI-Guided Prostate Biopsy Images related to Ultrasound - Prostate Sponsored ...

  19. Ultrasound -- Pelvis

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    Full Text Available ... Ultrasound - Pelvis Ultrasound imaging of the pelvis uses sound waves to produce pictures of the structures and ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  20. Prostate Ultrasound

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    Full Text Available ... Z Ultrasound - Prostate Ultrasound of the prostate uses sound waves to produce pictures of a man’s prostate ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  1. Ultrasound -- Pelvis

    Science.gov (United States)

    ... endometrial polyps fibroids cancer, especially in patients with abnormal uterine bleeding Some physicians also use 3-D ultrasound or ... Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding Ovarian Cancer Images related to Ultrasound - Pelvis Sponsored ...

  2. Mechanistic models for cancer development after short time radiation exposure

    International Nuclear Information System (INIS)

    Kottbauer, M. M.

    1997-12-01

    In this work two biological based models were developed. First the single-hit model for solid tumors (SHM-S) and second the single-hit model for leukemia (SHM-L). These models are a further development of the Armitage-Doll model for the special case of a short time radiation exposure. The basis of the models is the multistage process of carcinogeneses. The single-hit models provide simultaneously the age-dependent cancer-rate of spontaneous and radiation induced tumors as well as the dose-effect relationships at any age after exposure. The SHM-S leads to a biological based dose-effect relationship, which is similar to the relative risk model suggested by the ICRP 60. The SHM-S describes the increased mortality rate of the bomb survivors more accurate than the relative risk model. The SHM-L results in an additive dose-effect relationship. It is shown that only small differences in the derivation of the two models lead to the two dose-effect relationships. Beside the radiation exposure the new models consider the decrease of the cancer mortality rate at higher ages (age>75) which can be traced back mainly to three causes: competitive causes of death, reduction of cell proliferation and reduction of risk groups. The single-hit models also consider children cancer, the different rates of incidence and mortality, influence of the immune system and the cell-killing effect. (author)

  3. SUPRA: open-source software-defined ultrasound processing for real-time applications : A 2D and 3D pipeline from beamforming to B-mode.

    Science.gov (United States)

    Göbl, Rüdiger; Navab, Nassir; Hennersperger, Christoph

    2018-06-01

    Research in ultrasound imaging is limited in reproducibility by two factors: First, many existing ultrasound pipelines are protected by intellectual property, rendering exchange of code difficult. Second, most pipelines are implemented in special hardware, resulting in limited flexibility of implemented processing steps on such platforms. With SUPRA, we propose an open-source pipeline for fully software-defined ultrasound processing for real-time applications to alleviate these problems. Covering all steps from beamforming to output of B-mode images, SUPRA can help improve the reproducibility of results and make modifications to the image acquisition mode accessible to the research community. We evaluate the pipeline qualitatively, quantitatively, and regarding its run time. The pipeline shows image quality comparable to a clinical system and backed by point spread function measurements a comparable resolution. Including all processing stages of a usual ultrasound pipeline, the run-time analysis shows that it can be executed in 2D and 3D on consumer GPUs in real time. Our software ultrasound pipeline opens up the research in image acquisition. Given access to ultrasound data from early stages (raw channel data, radiofrequency data), it simplifies the development in imaging. Furthermore, it tackles the reproducibility of research results, as code can be shared easily and even be executed without dedicated ultrasound hardware.

  4. Acute Exposure Guideline Levels (AEGLs) for Time Varying Toxic Plumes

    Science.gov (United States)

    2014-09-12

    loading rates between the density values given as Arho(b-1,k) and Arho(b,k). The line labeled ‘ extrap .’above b = 1 in Table 3 records the derived...exposure times and an inverse quadratic law for densities lower than 8.26 mg/m3. The line labeled ‘ extrap .’ at the bottom of the table gives the...6 (labeled “ extrap .” above) are simply duplicated from the adjacent band b = 5. This exponent is also used to define the lowest density value Brho

  5. A semi-analytical model of a time reversal cavity for high-amplitude focused ultrasound applications

    Science.gov (United States)

    Robin, J.; Tanter, M.; Pernot, M.

    2017-09-01

    Time reversal cavities (TRC) have been proposed as an efficient approach for 3D ultrasound therapy. They allow the precise spatio-temporal focusing of high-power ultrasound pulses within a large region of interest with a low number of transducers. Leaky TRCs are usually built by placing a multiple scattering medium, such as a random rod forest, in a reverberating cavity, and the final peak pressure gain of the device only depends on the temporal length of its impulse response. Such multiple scattering in a reverberating cavity is a complex phenomenon, and optimisation of the device’s gain is usually a cumbersome process, mostly empirical, and requiring numerical simulations with extremely long computation times. In this paper, we present a semi-analytical model for the fast optimisation of a TRC. This model decouples ultrasound propagation in an empty cavity and multiple scattering in a multiple scattering medium. It was validated numerically and experimentally using a 2D-TRC and numerically using a 3D-TRC. Finally, the model was used to determine rapidly the optimal parameters of the 3D-TRC which had been confirmed by numerical simulations.

  6. [Mobile hospital -real time mobile telehealthcare system with ultrasound and CT van using high-speed satellite communication-].

    Science.gov (United States)

    Takizawa, Masaomi; Miyashita, Toyohisa; Murase, Sumio; Kanda, Hirohito; Karaki, Yoshiaki; Yagi, Kazuo; Ohue, Toru

    2003-01-01

    A real-time telescreening system is developed to detect early diseases for rural area residents using two types of mobile vans with a portable satellite station. The system consists of a satellite communication system with 1.5Mbps of the JCSAT-1B satellite, a spiral CT van, an ultrasound imaging van with two video conference system, a DICOM server and a multicast communication unit. The video image and examination image data are transmitted from the van to hospitals and the university simultaneously. Physician in the hospital observes and interprets exam images from the van and watches the video images of the position of ultrasound transducer on screenee in the van. After the observation images, physician explains a results of the examination by the video conference system. Seventy lung CT screening and 203 ultrasound screening were done from March to June 2002. The trial of this real time screening suggested that rural residents are given better healthcare without visit to the hospital. And it will open the gateway to reduce the medical cost and medical divide between city area and rural area.

  7. Cadmium and mercury exposure over time in Swedish children

    Energy Technology Data Exchange (ETDEWEB)

    Lundh, T., E-mail: Thomas.Lundh@med.lu.se [Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, SE−22185 Lund (Sweden); Axmon, A., E-mail: Anna.Axmon@med.lu.se [Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, SE−22185 Lund (Sweden); Skerfving, S., E-mail: Staffan.Skerfving@med.lu.se [Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, SE−22185 Lund (Sweden); Broberg, K., E-mail: Karin.Broberg@ki.se [Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, SE−22185 Lund (Sweden); Unit of Metals and Health, Institute of Environmental Medicine, Karolinska Institutet, Nobels väg 13, SE-171 77 Stockholm (Sweden)

    2016-10-15

    Purpose: Knowledge about changes in exposure to toxic metals over time remains very sparse, in particular for children, the most vulnerable group. Here, we assessed whether a reduction in environmental pollution with cadmium (Cd) and mercury (Hg) caused a change in exposure over time. In total, 1257 children (age 4–9) in two towns in Sweden were sampled once in 1986–2013. Blood concentrations of Cd (b-Cd; n=1120) and Hg (b-Hg; n=560) were determined. Results: The median b-Cd was 0.10 (geometric mean 0.10; range 0.010–0.61) μg/L and b-Hg was 0.91 (geometric mean 0.83; range 0.021–8.2) μg/L. Children living close to a smelter had higher b-Cd and b-Hg than those in urban and rural areas. There was no sex difference in b-Cd or b-Hg, and b-Cd and b-Hg showed no significant accumulation by age. b-Cd decreased only slightly (0.7% per year, p<0.001) over the study period. In contrast, b-Hg did show a clear decrease over the study period (3% per year, p<0.001). Conclusions: The exposure to Cd was very low but still might increase the risk of disease later in life. Moreover, b-Cd only showed a minor decrease, indicating that Cd pollution should be further restricted. b-Hg was relatively low and decreasing, probably because of reduced use of dental amalgam and lower Hg intake from fish. The b-Cd and b-Hg levels decreased much less than the levels of lead in the blood as previously found in the same children. - Highlights: • There are few studies of time trends for exposure to toxic metals, except for lead. • 1986–2013 we studied blood levels of cadmium and mercury in 1257 Swedish children. • The median blood concentration of cadmium was 0.10 μg/L, of mercury 0.83 μg/L. • Cadmium perhaps decreased by 0.7% per year, mercury by 3% per year. • Cadmium accumulation may result in toxic levels in elderly women.

  8. Value of Abdominal Radiography, Colonic Transit Time, and Rectal Ultrasound Scanning in the Diagnosis of Idiopathic Constipation in Children : A Systematic Review

    NARCIS (Netherlands)

    Berger, Marjolein Y.; Tabbers, Merit M.; Kurver, Miranda J.; Boluyt, Nicole; Benninga, Marc A.

    Objective To perform a systematic review evaluating the value of abdominal radiography, colonic transit time (CTT), and rectal ultrasound scanning in the diagnosis of idiopathic constipation in children. Study design Eligible studies were those assessing diagnostic accuracy of abdominal radiography,

  9. Real-time non-rigid target tracking for ultrasound-guided clinical interventions

    Science.gov (United States)

    Zachiu, C.; Ries, M.; Ramaekers, P.; Guey, J.-L.; Moonen, C. T. W.; de Senneville, B. Denis

    2017-10-01

    Biological motion is a problem for non- or mini-invasive interventions when conducted in mobile/deformable organs due to the targeted pathology moving/deforming with the organ. This may lead to high miss rates and/or incomplete treatment of the pathology. Therefore, real-time tracking of the target anatomy during the intervention would be beneficial for such applications. Since the aforementioned interventions are often conducted under B-mode ultrasound (US) guidance, target tracking can be achieved via image registration, by comparing the acquired US images to a separate image established as positional reference. However, such US images are intrinsically altered by speckle noise, introducing incoherent gray-level intensity variations. This may prove problematic for existing intensity-based registration methods. In the current study we address US-based target tracking by employing the recently proposed EVolution registration algorithm. The method is, by construction, robust to transient gray-level intensities. Instead of directly matching image intensities, EVolution aligns similar contrast patterns in the images. Moreover, the displacement is computed by evaluating a matching criterion for image sub-regions rather than on a point-by-point basis, which typically provides more robust motion estimates. However, unlike similar previously published approaches, which assume rigid displacements in the image sub-regions, the EVolution algorithm integrates the matching criterion in a global functional, allowing the estimation of an elastic dense deformation. The approach was validated for soft tissue tracking under free-breathing conditions on the abdomen of seven healthy volunteers. Contact echography was performed on all volunteers, while three of the volunteers also underwent standoff echography. Each of the two modalities is predominantly specific to a particular type of non- or mini-invasive clinical intervention. The method demonstrated on average an accuracy of

  10. Workflow and intervention times of MR-guided focused ultrasound - Predicting the impact of new techniques.

    Science.gov (United States)

    Loeve, Arjo J; Al-Issawi, Jumana; Fernandez-Gutiérrez, Fabiola; Langø, Thomas; Strehlow, Jan; Haase, Sabrina; Matzko, Matthias; Napoli, Alessandro; Melzer, Andreas; Dankelman, Jenny

    2016-04-01

    Magnetic resonance guided focused ultrasound surgery (MRgFUS) has become an attractive, non-invasive treatment for benign and malignant tumours, and offers specific benefits for poorly accessible locations in the liver. However, the presence of the ribcage and the occurrence of liver motion due to respiration limit the applicability MRgFUS. Several techniques are being developed to address these issues or to decrease treatment times in other ways. However, the potential benefit of such improvements has not been quantified. In this research, the detailed workflow of current MRgFUS procedures was determined qualitatively and quantitatively by using observation studies on uterine MRgFUS interventions, and the bottlenecks in MRgFUS were identified. A validated simulation model based on discrete events simulation was developed to quantitatively predict the effect of new technological developments on the intervention duration of MRgFUS on the liver. During the observation studies, the duration and occurrence frequencies of all actions and decisions in the MRgFUS workflow were registered, as were the occurrence frequencies of motion detections and intervention halts. The observation results show that current MRgFUS uterine interventions take on average 213min. Organ motion was detected on average 2.9 times per intervention, of which on average 1.0 actually caused a need for rework. Nevertheless, these motion occurrences and the actions required to continue after their detection consumed on average 11% and up to 29% of the total intervention duration. The simulation results suggest that, depending on the motion occurrence frequency, the addition of new technology to automate currently manual MRgFUS tasks and motion compensation could potentially reduce the intervention durations by 98.4% (from 256h 5min to 4h 4min) in the case of 90% motion occurrence, and with 24% (from 5h 19min to 4h 2min) in the case of no motion. In conclusion, new tools were developed to predict how

  11. Copper patinas formed in different atmospheres and exposure times

    International Nuclear Information System (INIS)

    Lobo, V.M.M.; Almeida, M.E.; Balmayor, M.; Tomas, H.M.L.R.

    1998-01-01

    Atmospheric corrosion products in copper samples, known as patinas, formed in industrial-marine, severe-marine and rural atmospheres exposed for 1,2,3, and 4 years, have been studied. The nature and structure of the products formed, characterized by X-ray diffraction (XRD) and infrared spectrometry (FTIR) depend on the time of exposure and the type of atmosphere. Copper patinas have been extensively mentioned in the literature, but the structural nature of their compounds, which vary according to the time of exposure and types of atmospheres, is still not adequately described in the literature. In order to give a contribution to this area, copper panels were exposed for 1,2,3, and 4 years in different types of atmospheres representing situations commonly observed, and subsequently the patinas were studied by XRD and FTIR 150 mm x 1 mm copper panels from commercial copper were exposed to three different atmospheric conditions in Portugal: industrial-marine (Leixoes, near Oporto, highly industrialized city close to the Ocean, subject to SO 2 from refineries); rural (Pego, small village in rural environment). The panels, attached to the appropriate stands, in accordance with ISO 8565 (1), were exposed for periods of 1,2,3 and 4 years, adequately collected for laboratory analysis by infrared spectrometry (FTIR). (Author)

  12. Ultrasound -- Pelvis

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    Full Text Available ... of the reflected sound waves (called the Doppler effect). A computer collects and processes the sounds and creates graphs ... Ultrasound provides real-time imaging, making it a good tool for guiding minimally ... known harmful effects on humans. top of page What are the ...

  13. Prostate Ultrasound

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    Full Text Available ... symptoms such as difficulty urinating or an elevated blood test result. It’s also used to investigate a nodule ... exam or prostate cancer screening exam. an elevated blood test result. difficulty urinating. Because ultrasound provides real-time ...

  14. Prostate Ultrasound

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    Full Text Available ... exam or prostate cancer screening exam. an elevated blood test result. difficulty urinating. Because ultrasound provides real-time images, it also can be used to guide procedures such as needle biopsies , in which a needle is used to sample cells (tissue) from an abnormal area in the ...

  15. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... the amplitude (loudness), frequency (pitch) and time it takes for the ultrasound signal to return from the area within the patient that is being examined to the transducer (the device placed on the patient's skin to send and ...

  16. Prostate Ultrasound

    Medline Plus

    Full Text Available ... the amplitude (loudness), frequency (pitch) and time it takes for the ultrasound signal to return from the area within the patient that is being examined to the transducer (the device placed on the patient's skin to send and ...

  17. The use of real time ultrasound scanning as a teaching method of anatomy in an undergraduate sonography and medical imaging degree in an Australian university

    International Nuclear Information System (INIS)

    Bowman, A.; Lawson, C.; McKillup, S.

    2016-01-01

    Background: Real-time ultrasound scanning is increasing in popularity as a teaching tool for human anatomy because it is non-invasive, offers real-time 3-D anatomy and is cheaper than dissections. Aim: To assess real-time ultrasound scanning as a teaching method of human anatomy, and to determine what teaching methods medical imaging and sonography students consider effective for understanding human anatomy. Method: Surveys were distributed to two consecutive cohorts of first year medical imaging and medical sonography students at CQUniversity. Participation was voluntary. Comparisons among teaching methods were made using repeated measures ANOVA. Results: Real-time ultrasound scanning was the most preferred method of delivery for anatomy classes overall especially compared to computer programs, videos, 3-D radiological images and dissection. Specifically, students indicated that ultrasound scanning was the preferred method to encourage learning from experience (F 7,231  = 2.942, p = 0.006), to develop team skills (F 7,231  = 4.550, p < 0.006), to follow complex instructions (F 7,231  = 4.656 p < 0.001) and to appreciate anatomical variation (F 7,231  = 2.067, p = 0.048). Dissection was the least favoured teaching method. Conclusion: Real-time ultrasound scanning is a useful tool for teaching anatomy, and animal dissections are a poor substitute for the use of human cadavers. - Highlights: • Real-time ultrasound scanning is a valid teaching tool for human anatomy. • Real-time ultrasound is preferred by students compared to other teaching methods. • Dissection is the least favoured method to learn anatomy. • Ultrasound encourages learning from experience and develops team skills.

  18. Reevaluation of time spent indoors used for exposure dose assessment

    International Nuclear Information System (INIS)

    Hirose, Katsumi; Fujimoto, Kenzo

    2016-01-01

    A time spent indoors of sixteen hours per day (indoor occupancy factor: 0.67) has been used to assess the radiation dose of residents who spend daily life in the area contaminated due to the nuclear accident in Japan. However, much longer time is considered to be spent indoors for recent modern life. United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) has been used an indoor occupancy factor of 0.8 since 1977 and a few reports suggested much higher indoor occupancy factors. Therefore it is important to reevaluate the indoor occupancy factor using current available survey data in Japan, such as 'NHK 2010 National Time Use Survey' and 'Survey on Time Use and Leisure Activities' of Statistics Bureau with certain assumption of time spent indoors in each daily activity. The total time spent indoors in a day is calculated to be 20.2 hours and its indoor occupancy factor is 0.84. Much lower indoor occupancy factors were derived from the survey data by Statistics Bureau for 10 to 14 and 15 to 19 years old groups and farmers who spend most of their time outdoors although present estimated indoor occupancy factor of 0.84 is still lower than those found in some of the relevant reports. A rounded indoor occupancy factor of 0.80 might be the appropriate conservative reference value to be used for the dose estimation of people who live in radioactively contaminated areas and for other relevant purposes of exposure assessment, taken into consideration the present results and values reported in United States Environmental Protection Agency (US EPA) and UNSCEAR. (author)

  19. Ultrasound simulator-assisted teaching of cardiac anatomy to preclinical anatomy students: A pilot randomized trial of a three-hour learning exposure.

    Science.gov (United States)

    Canty, David Jeffrey; Hayes, Jenny A; Story, David Andrew; Royse, Colin Forbes

    2015-01-01

    Ultrasound simulation allows students to virtually explore internal anatomy by producing accurate, moving, color, three-dimensional rendered slices from any angle or approach leaving the organs and their relationships intact without requirement for consumables. The aim was to determine the feasibility and efficacy of self-directed learning of cardiac anatomy with an ultrasound simulator compared to cadavers and plastic models. After a single cardiac anatomy lecture, fifty university anatomy students participated in a three-hour supervised self-directed learning exposure in groups of five, randomized to an ultrasound simulator or human cadaveric specimens and plastic models. Pre- and post-tests were conducted using pictorial and non-pictorial multiple-choice questions (MCQs). Simulator students completed a survey on their experience. Four simulator and seven cadaver group students did not attend after randomization. Simulator use in groups of five students was feasible and feedback from participants was very positive. Baseline test scores were similar (P = 0.9) between groups. After the learning intervention, there was no difference between groups in change in total test score (P = 0.37), whether they were pictorial (P = 0.6) or non-pictorial (P = 0.21). In both groups there was an increase in total test scores (simulator +19.8 ±12.4%% and cadaver: +16.4% ± 10.2, P human cadaveric prosections for learning cardiac anatomy. © 2014 American Association of Anatomists.

  20. Inattentional blindness is influenced by exposure time not motion speed.

    Science.gov (United States)

    Kreitz, Carina; Furley, Philip; Memmert, Daniel

    2016-01-01

    Inattentional blindness is a striking phenomenon in which a salient object within the visual field goes unnoticed because it is unexpected, and attention is focused elsewhere. Several attributes of the unexpected object, such as size and animacy, have been shown to influence the probability of inattentional blindness. At present it is unclear whether or how the speed of a moving unexpected object influences inattentional blindness. We demonstrated that inattentional blindness rates are considerably lower if the unexpected object moves more slowly, suggesting that it is the mere exposure time of the object rather than a higher saliency potentially induced by higher speed that determines the likelihood of its detection. Alternative explanations could be ruled out: The effect is not based on a pop-out effect arising from different motion speeds in relation to the primary-task stimuli (Experiment 2), nor is it based on a higher saliency of slow-moving unexpected objects (Experiment 3).

  1. Obstetrical ultrasound

    International Nuclear Information System (INIS)

    Bundy, A.L.

    1988-01-01

    The use of diagnostic ultrasound in obstetrics may provide fuel for legal action. While most legal implications of this relatively new imaging modality are purely speculative, some have already given rise to legal action. Several situations will likely provide a basis for the courts to find against the physician. The failure to perform a sonogram when clinically indicated will most likely be the strongest plaintiff argument. Other major concerns include the use and availability of state-of-the-art equipment, as well as interpretation of the scans by a trained physician. Obstetrical ultrasound is usually performed by a radiologist or obstetrician. However, many physicians performing these examinations have had little or no formal training in the field. While this is now being remedied by the respective board examines who require a certain amount of training, it may not be enough. When ultrasound-related cases reach the courts, the involved physicians will most likely be regarded as experts in the field and, therefore, will be held to a very high standard of care. This would be difficult to achieve without formal training. At the present time, the American Board of Radiology requires more training time in ultrasound than the American Board of Obstetrics and Gynecology

  2. Real-time ultrasound-tagging to track the 2D motion of the common carotid artery wall in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Zahnd, Guillaume, E-mail: g.zahnd@erasmusmc.nl [Biomedical Imaging Group Rotterdam, Departments of Radiology and Medical Informatics, Erasmus MC, Rotterdam 3000 CA (Netherlands); Salles, Sébastien; Liebgott, Hervé; Vray, Didier [Université de Lyon, CREATIS, CNRS UMR 5220, INSERM U1044, INSA-Lyon, Université Lyon 1, Lyon 69100 (France); Sérusclat, André [Department of Radiology, Louis Pradel Hospital, Lyon 69500 (France); Moulin, Philippe [Department of Endocrinology, Louis Pradel Hospital, Hospices Civils de Lyon, Université Lyon 1, Lyon 69100, France and INSERM UMR 1060, Lyon 69500 (France)

    2015-02-15

    Purpose: Tracking the motion of biological tissues represents an important issue in the field of medical ultrasound imaging. However, the longitudinal component of the motion (i.e., perpendicular to the beam axis) remains more challenging to extract due to the rather coarse resolution cell of ultrasound scanners along this direction. The aim of this study is to introduce a real-time beamforming strategy dedicated to acquire tagged images featuring a distinct pattern in the objective to ease the tracking. Methods: Under the conditions of the Fraunhofer approximation, a specific apodization function was applied to the received raw channel data, in real-time during image acquisition, in order to introduce a periodic oscillations pattern along the longitudinal direction of the radio frequency signal. Analytic signals were then extracted from the tagged images, and subpixel motion tracking of the intima–media complex was subsequently performed offline, by means of a previously introduced bidimensional analytic phase-based estimator. Results: The authors’ framework was applied in vivo on the common carotid artery from 20 young healthy volunteers and 6 elderly patients with high atherosclerosis risk. Cine-loops of tagged images were acquired during three cardiac cycles. Evaluated against reference trajectories manually generated by three experienced analysts, the mean absolute tracking error was 98 ± 84 μm and 55 ± 44 μm in the longitudinal and axial directions, respectively. These errors corresponded to 28% ± 23% and 13% ± 9% of the longitudinal and axial amplitude of the assessed motion, respectively. Conclusions: The proposed framework enables tagged ultrasound images of in vivo tissues to be acquired in real-time. Such unconventional beamforming strategy contributes to improve tracking accuracy and could potentially benefit to the interpretation and diagnosis of biomedical images.

  3. Maternal exposure to ambient air pollution and fetal growth in North-East Scotland: A population-based study using routine ultrasound scans.

    Science.gov (United States)

    Clemens, Tom; Turner, Steve; Dibben, Chris

    2017-10-01

    Maternal ambient air pollution exposure is associated with reduced birthweight. Few studies have examined the effect on growth in utero and none have examined the effect of exposure to particulates less than 2.5µm (PM 2.5 ) and possible effect modification by smoking status. Examine the effect of maternal exposure to ambient concentrations of PM 10 , PM 2.5 and nitrogen dioxide (NO 2 ) for in utero fetal growth, size at birth and effect modification by smoking status. Administratively acquired second and third trimester fetal measurements (bi-parietal diameter, femur length and abdominal circumference), birth outcomes (weight, crown heel length and occipito-frontal circumference) and maternal details were obtained from routine fetal ultrasound scans and maternity records (period 1994-2009). These were modelled against residential annual pollution concentrations (calendar year mean) adjusting for covariates and stratifying by smoking status. In the whole sample (n=13,775 pregnancies), exposure to PM 10 , PM 2.5 and NO 2 was associated with reductions in measurements at birth and biparietal diameter from late second trimester onwards. Among mothers who did not smoke at all during pregnancy (n=11,075), associations between biparietal diameter and pollution exposure remained significant but were insignificant among those who did smoke (n=2700). Femur length and abdominal circumference were not significantly associated with pollution exposure. Fetal growth is strongly associated with particulates exposure from later in second trimester onwards but the effect appears to be subsumed by smoking. Typical ambient exposures in this study were relatively low compared to other studies and given these results, it may be necessary to consider reducing recommended "safe" ambient air exposures. Copyright © 2017. Published by Elsevier Ltd.

  4. MO-FG-CAMPUS-JeP3-04: Feasibility Study of Real-Time Ultrasound Monitoring for Abdominal Stereotactic Body Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Su, Lin; Kien Ng, Sook; Zhang, Ying; Herman, Joseph; Wong, John; Ding, Kai [Department of Radiation Oncology, John Hopkins University, Baltimore, MD (United States); Ji, Tianlong [Department of Radiation Oncology, The First Hospital of China Medical University, Shenyang, Liaoning (China); Iordachita, Iulian [Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD (United States); Tutkun Sen, H.; Kazanzides, Peter; Lediju Bell, Muyinatu A. [Department of Computer Science, Johns Hopkins University, Baltimore, MD (United States)

    2016-06-15

    Purpose: Ultrasound is ideal for real-time monitoring in radiotherapy with high soft tissue contrast, non-ionization, portability, and cost effectiveness. Few studies investigated clinical application of real-time ultrasound monitoring for abdominal stereotactic body radiation therapy (SBRT). This study aims to demonstrate the feasibility of real-time monitoring of 3D target motion using 4D ultrasound. Methods: An ultrasound probe holding system was designed to allow clinician to freely move and lock ultrasound probe. For phantom study, an abdominal ultrasound phantom was secured on a 2D programmable respiratory motion stage. One side of the stage was elevated than another side to generate 3D motion. The motion stage made periodic breath-hold movement. Phantom movement tracked by infrared camera was considered as ground truth. For volunteer study three healthy subjects underwent the same setup for abdominal SBRT with active breath control (ABC). 4D ultrasound B-mode images were acquired for both phantom and volunteers for real-time monitoring. 10 breath-hold cycles were monitored for each experiment. For phantom, the target motion tracked by ultrasound was compared with motion tracked by infrared camera. For healthy volunteers, the reproducibility of ABC breath-hold was evaluated. Results: Volunteer study showed the ultrasound system fitted well to the clinical SBRT setup. The reproducibility for 10 breath-holds is less than 2 mm in three directions for all three volunteers. For phantom study the motion between inspiration and expiration captured by camera (ground truth) is 2.35±0.02 mm, 1.28±0.04 mm, 8.85±0.03 mm in LR, AP, SI directly, respectively. The motion monitored by ultrasound is 2.21±0.07 mm, 1.32±0.12mm, 9.10±0.08mm, respectively. The motion monitoring error in any direction is less than 0.5 mm. Conclusion: The volunteer study proved the clinical feasibility of real-time ultrasound monitoring for abdominal SBRT. The phantom and volunteer ABC

  5. MO-FG-CAMPUS-JeP3-04: Feasibility Study of Real-Time Ultrasound Monitoring for Abdominal Stereotactic Body Radiation Therapy

    International Nuclear Information System (INIS)

    Su, Lin; Kien Ng, Sook; Zhang, Ying; Herman, Joseph; Wong, John; Ding, Kai; Ji, Tianlong; Iordachita, Iulian; Tutkun Sen, H.; Kazanzides, Peter; Lediju Bell, Muyinatu A.

    2016-01-01

    Purpose: Ultrasound is ideal for real-time monitoring in radiotherapy with high soft tissue contrast, non-ionization, portability, and cost effectiveness. Few studies investigated clinical application of real-time ultrasound monitoring for abdominal stereotactic body radiation therapy (SBRT). This study aims to demonstrate the feasibility of real-time monitoring of 3D target motion using 4D ultrasound. Methods: An ultrasound probe holding system was designed to allow clinician to freely move and lock ultrasound probe. For phantom study, an abdominal ultrasound phantom was secured on a 2D programmable respiratory motion stage. One side of the stage was elevated than another side to generate 3D motion. The motion stage made periodic breath-hold movement. Phantom movement tracked by infrared camera was considered as ground truth. For volunteer study three healthy subjects underwent the same setup for abdominal SBRT with active breath control (ABC). 4D ultrasound B-mode images were acquired for both phantom and volunteers for real-time monitoring. 10 breath-hold cycles were monitored for each experiment. For phantom, the target motion tracked by ultrasound was compared with motion tracked by infrared camera. For healthy volunteers, the reproducibility of ABC breath-hold was evaluated. Results: Volunteer study showed the ultrasound system fitted well to the clinical SBRT setup. The reproducibility for 10 breath-holds is less than 2 mm in three directions for all three volunteers. For phantom study the motion between inspiration and expiration captured by camera (ground truth) is 2.35±0.02 mm, 1.28±0.04 mm, 8.85±0.03 mm in LR, AP, SI directly, respectively. The motion monitored by ultrasound is 2.21±0.07 mm, 1.32±0.12mm, 9.10±0.08mm, respectively. The motion monitoring error in any direction is less than 0.5 mm. Conclusion: The volunteer study proved the clinical feasibility of real-time ultrasound monitoring for abdominal SBRT. The phantom and volunteer ABC

  6. Multichannel, time-resolved picosecond laser ultrasound imaging and spectroscopy with custom complementary metal-oxide-semiconductor detector

    International Nuclear Information System (INIS)

    Smith, Richard J.; Light, Roger A.; Johnston, Nicholas S.; Pitter, Mark C.; Somekh, Mike G.; Sharples, Steve D.

    2010-01-01

    This paper presents a multichannel, time-resolved picosecond laser ultrasound system that uses a custom complementary metal-oxide-semiconductor linear array detector. This novel sensor allows parallel phase-sensitive detection of very low contrast modulated signals with performance in each channel comparable to that of a discrete photodiode and a lock-in amplifier. Application of the instrument is demonstrated by parallelizing spatial measurements to produce two-dimensional thickness maps on a layered sample, and spectroscopic parallelization is demonstrated by presenting the measured Brillouin oscillations from a gallium arsenide wafer. This paper demonstrates the significant advantages of our approach to pump probe systems, especially picosecond ultrasonics.

  7. Multichannel, time-resolved picosecond laser ultrasound imaging and spectroscopy with custom complementary metal-oxide-semiconductor detector

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Richard J.; Light, Roger A.; Johnston, Nicholas S.; Pitter, Mark C.; Somekh, Mike G. [Institute of Biophysics, Imaging and Optical Science, University of Nottingham, Nottinghamshire NG7 2RD (United Kingdom); Sharples, Steve D. [Applied Optics Group, Electrical Systems and Optics Research Division, University of Nottingham, Nottinghamshire NG7 2RD (United Kingdom)

    2010-02-15

    This paper presents a multichannel, time-resolved picosecond laser ultrasound system that uses a custom complementary metal-oxide-semiconductor linear array detector. This novel sensor allows parallel phase-sensitive detection of very low contrast modulated signals with performance in each channel comparable to that of a discrete photodiode and a lock-in amplifier. Application of the instrument is demonstrated by parallelizing spatial measurements to produce two-dimensional thickness maps on a layered sample, and spectroscopic parallelization is demonstrated by presenting the measured Brillouin oscillations from a gallium arsenide wafer. This paper demonstrates the significant advantages of our approach to pump probe systems, especially picosecond ultrasonics.

  8. Children's (Pediatric) Abdominal Ultrasound Imaging

    Medline Plus

    Full Text Available ... patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... vomiting in young infants Because ultrasound provides real-time images, images that are renewed continuously, it also ...

  9. Making Time for Nature: Visual Exposure to Natural Environments Lengthens Subjective Time Perception and Reduces Impulsivity.

    Directory of Open Access Journals (Sweden)

    Meredith S Berry

    Full Text Available Impulsivity in delay discounting is associated with maladaptive behaviors such as overeating and drug and alcohol abuse. Researchers have recently noted that delay discounting, even when measured by a brief laboratory task, may be the best predictor of human health related behaviors (e.g., exercise currently available. Identifying techniques to decrease impulsivity in delay discounting, therefore, could help improve decision-making on a global scale. Visual exposure to natural environments is one recent approach shown to decrease impulsive decision-making in a delay discounting task, although the mechanism driving this result is currently unknown. The present experiment was thus designed to evaluate not only whether visual exposure to natural (mountains, lakes relative to built (buildings, cities environments resulted in less impulsivity, but also whether this exposure influenced time perception. Participants were randomly assigned to either a natural environment condition or a built environment condition. Participants viewed photographs of either natural scenes or built scenes before and during a delay discounting task in which they made choices about receiving immediate or delayed hypothetical monetary outcomes. Participants also completed an interval bisection task in which natural or built stimuli were judged as relatively longer or shorter presentation durations. Following the delay discounting and interval bisection tasks, additional measures of time perception were administered, including how many minutes participants thought had passed during the session and a scale measurement of whether time "flew" or "dragged" during the session. Participants exposed to natural as opposed to built scenes were less impulsive and also reported longer subjective session times, although no differences across groups were revealed with the interval bisection task. These results are the first to suggest that decreased impulsivity from exposure to natural as

  10. Wide-field time-correlated single photon counting (TCSPC) microscopy with time resolution below the frame exposure time

    Energy Technology Data Exchange (ETDEWEB)

    Hirvonen, Liisa M. [Department of Physics, King' s College London, Strand, London WC2R 2LS (United Kingdom); Petrášek, Zdeněk [Max Planck Institute of Biochemistry, Department of Cellular and Molecular Biophysics, Am Klopferspitz 18, D-82152 Martinsried (Germany); Suhling, Klaus, E-mail: klaus.suhling@kcl.ac.uk [Department of Physics, King' s College London, Strand, London WC2R 2LS (United Kingdom)

    2015-07-01

    Fast frame rate CMOS cameras in combination with photon counting intensifiers can be used for fluorescence imaging with single photon sensitivity at kHz frame rates. We show here how the phosphor decay of the image intensifier can be exploited for accurate timing of photon arrival well below the camera exposure time. This is achieved by taking ratios of the intensity of the photon events in two subsequent frames, and effectively allows wide-field TCSPC. This technique was used for measuring decays of ruthenium compound Ru(dpp) with lifetimes as low as 1 μs with 18.5 μs frame exposure time, including in living HeLa cells, using around 0.1 μW excitation power. We speculate that by using an image intensifier with a faster phosphor decay to match a higher camera frame rate, photon arrival time measurements on the nanosecond time scale could well be possible.

  11. Prehospital Ultrasound

    Directory of Open Access Journals (Sweden)

    Jen-Tang Sun

    2014-06-01

    Full Text Available Ultrasound is a commonly used diagnostic tool in clinical conditions. With recent developments in technology, use of portable ultrasound devices has become feasible in prehospital settings. Many studies also proved the feasibility and accuracy of prehospital ultrasound. In this article, we focus on the use of prehospital ultrasound, with emphasis on trauma and chest ultrasound.

  12. Abdominal ultrasound referred by the Emergency department – Can sonographer findings help guide timely patient management?

    International Nuclear Information System (INIS)

    Schneider, Michal; Bloesch, Justin; Lombardo, Paul

    2014-01-01

    Objective: To compare sonographer findings with radiologists' reports regarding the level of agreement, ability to answer the clinical question, and the use of hedging (descriptive words that do not commit to a definitive diagnosis) in abdominal ultrasound cases referred by the Emergency department. Other criteria compared included caveats of image quality and requests for further investigations. Methods: Abdominal ultrasound examinations referred by the Emergency department at a large regional tertiary hospital were retrospectively reviewed and sonographer findings compared with radiologists' reports. A consultant Intensivist scored all examinations into one of four categories according to the level of diagnostic agreement between the sonographer and associated radiologists. The same rater also identified where hedging terminology was used, whether the clinical question posed was answered and when further requests for investigations (including imaging) were made. The proportion of scores between sonographers and radiologists for each outcome variable were analysed using Fisher Exact tests. Results: Eighty-six cases were identified for this study. Of those, 73 (84.9%) were in complete agreement. In 12 cases (14.0%) a minor discrepancy was reported and only one case (1.1%) was scored as moderately discrepant between sonographers findings and radiologists' reports. There were no significant differences in the use of hedging, ability to answer the clinical question, requests for further investigations or interpretation of image quality. Conclusion: Sonographer findings for cases of abdominal ultrasound referred by the Emergency department have a high level of agreement with radiologists' reports and could form the basis for acute patient care when radiologists' reports are unavailable

  13. Ultrasound-Guided real-time pterygopalatine block for analgesia in an oral cancer patient

    Directory of Open Access Journals (Sweden)

    Nishkarsh Gupta

    2018-01-01

    Full Text Available Oral cancers are one of the most common cancers in India. These patients have pain during the course of the disease. Various drugs including opioid and nonsteroidal anti-inflammatory drug have been used to manage pain. However, these are associated with side effects such as constipation and vomiting. An early interventional block may decrease the requirement for analgesics and improve the overall quality of life. We describe a case of oral carcinoma successfully managed with ultrasound-guided pterygopalatine block.

  14. SonoNet: Real-Time Detection and Localisation of Fetal Standard Scan Planes in Freehand Ultrasound.

    Science.gov (United States)

    Baumgartner, Christian F; Kamnitsas, Konstantinos; Matthew, Jacqueline; Fletcher, Tara P; Smith, Sandra; Koch, Lisa M; Kainz, Bernhard; Rueckert, Daniel

    2017-11-01

    Identifying and interpreting fetal standard scan planes during 2-D ultrasound mid-pregnancy examinations are highly complex tasks, which require years of training. Apart from guiding the probe to the correct location, it can be equally difficult for a non-expert to identify relevant structures within the image. Automatic image processing can provide tools to help experienced as well as inexperienced operators with these tasks. In this paper, we propose a novel method based on convolutional neural networks, which can automatically detect 13 fetal standard views in freehand 2-D ultrasound data as well as provide a localization of the fetal structures via a bounding box. An important contribution is that the network learns to localize the target anatomy using weak supervision based on image-level labels only. The network architecture is designed to operate in real-time while providing optimal output for the localization task. We present results for real-time annotation, retrospective frame retrieval from saved videos, and localization on a very large and challenging dataset consisting of images and video recordings of full clinical anomaly screenings. We found that the proposed method achieved an average F1-score of 0.798 in a realistic classification experiment modeling real-time detection, and obtained a 90.09% accuracy for retrospective frame retrieval. Moreover, an accuracy of 77.8% was achieved on the localization task.

  15. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... a pelvic ultrasound examination. Doppler ultrasound , also called color Doppler ultrasonography, is a special ultrasound technique that ... and processes the sounds and creates graphs or color pictures that represent the flow of blood through ...

  16. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. There are ... Ultrasound page for more information . Ultrasound examinations can help diagnose symptoms experienced by women such as: pelvic ...

  17. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... three types of pelvic ultrasound: abdominal, vaginal (for women), and rectal (for men). These exams are frequently ... pelvic ultrasound: abdominal ( transabdominal ) vaginal ( transvaginal / endovaginal ) for women rectal ( transrectal ) for men A Doppler ultrasound exam ...

  18. SU-G-JeP4-12: Real-Time Organ Motion Monitoring Using Ultrasound and KV Fluoroscopy During Lung SBRT Delivery

    International Nuclear Information System (INIS)

    Omari, E; Tai, A; Li, X; Cooper, D; Lachaine, M

    2016-01-01

    Purpose: Real-time ultrasound monitoring during SBRT is advantageous in understanding and identifying motion irregularities which may cause geometric misses. In this work, we propose to utilize real-time ultrasound to track the diaphragm in conjunction with periodical kV fluoroscopy to monitor motion of tumor or landmarks during SBRT delivery. Methods: Transabdominal Ultrasound (TAUS) b-mode images were collected from 10 healthy volunteers using the Clarity Autoscan System (Elekta). The autoscan transducer, which has a center frequency of 5 MHz, was utilized for the scans. The acquired images were contoured using the Clarity Automatic Fusion and Contouring workstation software. Monitoring sessions of 5 minute length were observed and recorded. The position correlation between tumor and diaphragm could be established with periodic kV fluoroscopy periodically acquired during treatment with Elekta XVI. We acquired data using a tissue mimicking ultrasound phantom with embedded spheres placed on a motion stand using ultrasound and kV Fluoroscopy. MIM software was utilized for image fusion. Correlation of diaphragm and target motion was also validated using 4D-MRI and 4D-CBCT. Results: The diaphragm was visualized as a hyperechoic region on the TAUS b-mode images. Volunteer set-up can be adjusted such that TAUS probe will not interfere with treatment beams. A segment of the diaphragm was contoured and selected as our tracking structure. Successful monitoring sessions of the diaphragm were recorded. For some volunteers, diaphragm motion over 2 times larger than the initial motion has been observed during tracking. For the phantom study, we were able to register the 2D kV Fluoroscopy with the US images for position comparison. Conclusion: We demonstrated the feasibility of tracking the diaphragm using real-time ultrasound. Real-time tracking can help in identifying such irregularities in the respiratory motion which is correlated to tumor motion. We also showed the

  19. Surgery for subacromial impingement syndrome in relation to intensities of occupational mechanical exposures across 10-year exposure time windows.

    Science.gov (United States)

    Dalbøge, Annett; Frost, Poul; Andersen, Johan Hviid; Svendsen, Susanne Wulff

    2018-03-01

    We aimed to identify intensities of occupational mechanical exposures (force, arm elevation and repetition) that do not entail an increased risk of surgery for subacromial impingement syndrome (SIS) even after prolonged durations of exposure. Additionally, we wanted to evaluate if exposure to hand-arm vibration (HAV) is an independent risk factor. We used data from a register-based cohort study of the entire Danish working population (n=2 374 403). During follow-up (2003-2008), 14 118 first-time events of surgery for SIS occurred. For each person, we linked register-based occupational codes (1993-2007) to a general population job exposure matrix to obtain year-by-year exposure intensities on measurement scales for force, upper arm elevation >90° and repetition and expert rated intensities of exposure to HAV. For 10-year exposure time windows, we calculated the duration of exposure at specific intensities above minimal (low, medium and high). We used a logistic regression technique equivalent to discrete survival analysis adjusting for cumulative effects of other mechanical exposures. We found indications of safe exposure intensities for repetition (median angular velocity 90° >2 min/day implied an increased risk reaching ORs of 1.7 and 1.5 after 10 years at low intensities. No associations were found for HAV. We found indications of safe exposure intensities for repetition. Any intensities of force and upper arm elevation >90° above minimal implied an increased risk across 10-year exposure time windows. No independent associations were found for HAV. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  20. Development of EndoTOFPET-US, a multi-modal endoscope for ultrasound and time of flight positron emission tomography

    International Nuclear Information System (INIS)

    Pizzichemi, M

    2014-01-01

    The EndoTOFPET-US project aims at delevoping a multi-modal imaging device that combines Ultrasound with Time-Of-Flight Positron Emission Tomography into an endoscopic imaging device. The goal is to obtain a coincidence time resolution of about 200 ps FWHM and sub-millimetric spatial resolution for the PET head, integrating the components in a very compact detector suitable for endoscopic use. The scanner will be exploited for the clinical test of new bio-markers especially targeted for prostate and pancreatic cancer as well as for diagnostic and surgical oncology. This paper focuses on the status of the Time-Of-Flight Positron Emission Tomograph under development for the EndoTOFPET-US project

  1. Noise exposure levels for musicians during rehearsal and performance times.

    Science.gov (United States)

    McIlvaine, Devon; Stewart, Michael; Anderson, Robert

    2012-03-01

    The purpose of this study was to determine daily noise doses and 8-hour time weighted averages for rock band musicians, crew members, and spectators during a typical rehearsal and performance using both Occupational Safety and Health Administration (OSHA) and National Institute of Occupational Safety and Health (NIOSH) measurement criteria. Personal noise dosimetry was completed on five members of a rock band during one 2-hr rehearsal and one 4-hr performance. Time-weighted averages (TWA) and daily dose values were calculated using both OSHA and NIOSH criteria and compared to industry guidelines for enrollment in hearing conservation programs and the use of hearing protection devices. TWA values ranged from 84.3 to 90.4 dBA (OSHA) and from 90.0 to 96.4 dBA (NIOSH) during the rehearsal. The same values ranged from 91.0 to 99.7 dBA (OSHA) and 94.0 to 102.8 dBA (NIOSH) for the performance. During the rehearsal, daily noise doses ranged from 45.54% to 106.7% (OSHA) and from 317.74% to 1396.07% (NIOSH). During the performance, doses ranged from 114.66% to 382.49% (OSHA) and from 793.31% to 5970.15% (NIOSH). The musicians in this study were exposed to dangerously high levels of noise and should be enrolled in a hearing conservation programs. Hearing protection devices should be worn, especially during performances. The OSHA measurement criteria yielded values significantly more conservative than those produced by NIOSH criteria. Audiologists should counsel musician-patients about the hazards of excessive noise (music) exposure and how to protect their hearing.

  2. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. There are three types of pelvic ultrasound: ...

  3. Surgery for subacromial impingement syndrome in relation to intensities of occupational mechanical exposures across 10-year exposure time windows

    DEFF Research Database (Denmark)

    Dalbøge, Annett; Frost, Poul; Andersen, Johan Hviid

    2018-01-01

    OBJECTIVES: We aimed to identify intensities of occupational mechanical exposures (force, arm elevation and repetition) that do not entail an increased risk of surgery for subacromial impingement syndrome (SIS) even after prolonged durations of exposure. Additionally, we wanted to evaluate...... if exposure to hand-arm vibration (HAV) is an independent risk factor. METHODS: We used data from a register-based cohort study of the entire Danish working population (n=2 374 403). During follow-up (2003-2008), 14 118 first-time events of surgery for SIS occurred. For each person, we linked register...... of exposure at specific intensities above minimal (low, medium and high). We used a logistic regression technique equivalent to discrete survival analysis adjusting for cumulative effects of other mechanical exposures. RESULTS: We found indications of safe exposure intensities for repetition (median angular...

  4. Time and frequency weightings and the assessment of sound exposure

    DEFF Research Database (Denmark)

    Ordoñez, Rodrigo Pizarro; de Toro, Miguel Angel Aranda; Hammershøi, Dorte

    2010-01-01

    Since the development of averaging/integrating sound level meters and frequency weighting networks in the 1950’s, measurement of the physical characteristics of sound has not changed a great deal. Advances have occurred in how the measured values are used (day-night averages, limit and action...... of the exposure. This information is being used to investigate metrics that can differentiate temporal characteristics (impulsive, fluctuating) as well as frequency characteristics (narrow-band or tonal dominance) of sound exposures. This presentation gives an overview of the existing sound measurement...... and analysis methods, that can provide a better representation of the effects of sound exposures on the hearing system...

  5. Effect of exposure time reduction towards sensitivity and SNR for computed radiography (CR) application in NDT

    International Nuclear Information System (INIS)

    Sapizah Rahim; Khairul Anuar Mohd Salleh; Noorhazleena Azaman; Shaharudin Sayuti; Siti Madiha Muhammad Amir; Arshad Yassin; Abdul Razak Hamzah

    2010-01-01

    Signal-to-noise ratio (SNR) and sensitivity study of Computed Radiography (CR) system with reduction of exposure time is presented. The purposes of this research are to determine the behavior of SNR toward three different thicknesses (step wedge; 5, 10 and 15 mm) and the ability of CR system to recognize hole type penetrameter when the exposure time decreased up to 80 % according to the exposure chart (D7; ISOVOLT Titan E). It is shown that the SNR is decreased with decreasing of exposure time percentage but the high quality image is achieved until 80 % reduction of exposure time. (author)

  6. ULA-OP 256: A 256-Channel Open Scanner for Development and Real-Time Implementation of New Ultrasound Methods.

    Science.gov (United States)

    Boni, Enrico; Bassi, Luca; Dallai, Alessandro; Guidi, Francesco; Meacci, Valentino; Ramalli, Alessandro; Ricci, Stefano; Tortoli, Piero

    2016-10-01

    Open scanners offer an increasing support to the ultrasound researchers who are involved in the experimental test of novel methods. Each system presents specific performance in terms of number of channels, flexibility, processing power, data storage capability, and overall dimensions. This paper reports the design criteria and hardware/software implementation details of a new 256-channel ultrasound advanced open platform. This system is organized in a modular architecture, including multiple front-end boards, interconnected by a high-speed (80 Gb/s) ring, capable of finely controlling all transmit (TX) and receive (RX) signals. High flexibility and processing power (equivalent to 2500 GFLOP) are guaranteed by the possibility of individually programming multiple digital signal processors and field programmable gate arrays. Eighty GB of on-board memory are available for the storage of prebeamforming, postbeamforming, and baseband data. The use of latest generation devices allowed to integrate all needed electronics in a small size ( 34 cm ×30 cm ×26 cm). The system implements a multiline beamformer that allows obtaining images of 96 lines by 2048 depths at a frame rate of 720 Hz (expandable to 3000 Hz). The multiline beamforming capability is also exploited to implement a real-time vector Doppler scheme in which a single TX and two independent RX apertures are simultaneously used to maintain the analysis over a full pulse repetition frequency range.

  7. Real-time image-based B-mode ultrasound image simulation of needles using tensor-product interpolation.

    Science.gov (United States)

    Zhu, Mengchen; Salcudean, Septimiu E

    2011-07-01

    In this paper, we propose an interpolation-based method for simulating rigid needles in B-mode ultrasound images in real time. We parameterize the needle B-mode image as a function of needle position and orientation. We collect needle images under various spatial configurations in a water-tank using a needle guidance robot. Then we use multidimensional tensor-product interpolation to simulate images of needles with arbitrary poses and positions using collected images. After further processing, the interpolated needle and seed images are superimposed on top of phantom or tissue image backgrounds. The similarity between the simulated and the real images is measured using a correlation metric. A comparison is also performed with in vivo images obtained during prostate brachytherapy. Our results, carried out for both the convex (transverse plane) and linear (sagittal/para-sagittal plane) arrays of a trans-rectal transducer indicate that our interpolation method produces good results while requiring modest computing resources. The needle simulation method we present can be extended to the simulation of ultrasound images of other wire-like objects. In particular, we have shown that the proposed approach can be used to simulate brachytherapy seeds.

  8. Ultrasound shock wave generator with one-bit time reversal in a dispersive medium, application to lithotripsy

    Science.gov (United States)

    Montaldo, Gabriel; Roux, Philippe; Derode, Arnaud; Negreira, Carlos; Fink, Mathias

    2002-02-01

    The building of high-power ultrasonic sources from piezoelectric ceramics is limited by the maximum voltage that the ceramics can endure. We have conceived a device that uses a small number of piezoelectric transducers fastened to a cylindrical metallic waveguide. A one-bit time- reversal operation transforms the long-lasting low-level dispersed wave forms into a sharp pulse, thus taking advantage of dispersion to generate high-power ultrasound. The pressure amplitude that is generated at the focus is found to be 15 times greater than that achieved with comparable standard techniques. Applications to lithotripsy are discussed and the destructive efficiency of the system is demonstrated on pieces of chalk.

  9. Novel needle guide reduces time to perform ultrasound-guided femoral nerve catheter placement: A randomised controlled trial.

    Science.gov (United States)

    Turan, Alparslan; Babazade, Rovnat; Elsharkawy, Hesham; Esa, Wael Ali Sakr; Maheshwari, Kamal; Farag, Ehab; Zimmerman, Nicole M; Soliman, Loran Mounir; Sessler, Daniel I

    2017-03-01

    Ultrasound-guided nerve blocks have become the standard when performing regional nerve blocks in anaesthesia. Infiniti Plus (CIVCO Medical Solutions, Kalona, Iowa, USA) is a needle guide that has been recently developed to help clinicians in performing ultrasound-guided nerve blocks. We tested the hypothesis that femoral nerve catheter placement carried out with the Infiniti Plus needle guide will be quicker to perform than without the Infiniti Plus. Secondary aims were to assess whether the Infiniti Plus needle guide decreased the number of block attempts and also whether it improved needle visibility. A randomised, controlled trial. Cleveland Clinic, Cleveland, Ohio, USA. We enrolled adult patients having elective total knee arthroplasty with a femoral nerve block and femoral nerve catheter. Patients, who were pregnant or those who had preexisting neuropathy involving the surgical limb, coagulopathy, infection at the block site or allergy to local anaesthetics were excluded. Patients were randomised into two groups to receive the ultrasound-guided femoral nerve catheter placement with or without the Infiniti Plus needle guide. The time taken to place the femoral nerve catheter, the number of attempts, the success rate and needle visibility were recorded. We used an overall α of 0.05 for both the primary and secondary analyses; the secondary analyses were Bonferroni corrected to control for multiple comparisons. The median (interquartile range Q1 to Q3) time to perform the femoral nerve catheter placement was 118 (100 to 150) s with Infiniti Plus and 177 (130 to 236) s without Infiniti Plus. Infiniti Plus significantly reduced the time spent performing femoral nerve catheterisation, with estimated ratio of means [(95% confidence interval), P value] of 0.67 [(0.60 to 0.75), P Infiniti Plus compared with no Infiniti Plus. However, Infiniti Plus had no effect on the odds of a successful femoral nerve catheter placement, number of attempts or percentage of perfect

  10. Children's (Pediatric) Abdominal Ultrasound Imaging

    Medline Plus

    Full Text Available ... radiation. Ultrasound scanning gives a clear picture of soft tissues that do not show up well on x-ray images. Ultrasound provides real-time imaging, making it a good tool for guiding ...

  11. Children's (Pediatric) Abdominal Ultrasound Imaging

    Medline Plus

    Full Text Available ... ultrasound images are captured in real-time, they can show the structure and movement of the body's ... kidneys bladder testicles ovaries uterus Abdominal ultrasound images can be used to help diagnose appendicitis in children. ...

  12. Study of the examination times using radiation equipments and the radiation exposure control

    Energy Technology Data Exchange (ETDEWEB)

    Koshida, Kichiro; Orito, Takeo; Maekawa, Ryuichi; Hiraki, Tatsunosuke [Kanazawa Univ. (Japan). School of Paramedicine; Koga, Sukehiko

    1985-01-01

    The relation between the examination time and the exposure to the personnel was investigated. In order to minimize radiation injury, special exposure dose-rate distribution curves were performed at the maximum exposure condition setting the phantom, and the examination times could be limited from the exprosure dose for the place where the personnel presented. The examination times are possible to be ten times by those with the Medical X-ray Protective Aprons.

  13. Study of the examination times using radiation equipments and the radiation exposure control

    International Nuclear Information System (INIS)

    Koshida, Kichiro; Orito, Takeo; Maekawa, Ryuichi; Hiraki, Tatsunosuke; Koga, Sukehiko.

    1985-01-01

    It was investigated for the relation between the examination times and the exposure to the personnel. At the purpose to minimize the radiation injury, the special exposure dose-rate distribution curves were performed at the maximum exposure condition setting the phantom, and the examination times could be limited from the exprosure dose for the place where the personnel presented. The examination times are possible to be ten times by those with the Medical X-ray Protective Aprons. (author)

  14. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... Radiation Therapy for Gynecologic Cancers Radiation Therapy for Prostate Cancer top of page This page was reviewed on ... Abdomen Children's (Pediatric) Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding ... Images related to Ultrasound - Pelvis Sponsored by Please ...

  15. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... endometrial polyps fibroids cancer, especially in patients with abnormal uterine bleeding Some physicians also use 3-D ultrasound or ... Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding Ovarian Cancer Images related to Ultrasound - Pelvis Sponsored ...

  16. Channel-Island Connectivity Affects Water Exposure Time Distributions in a Coastal River Delta

    Science.gov (United States)

    Hiatt, Matthew; Castañeda-Moya, Edward; Twilley, Robert; Hodges, Ben R.; Passalacqua, Paola

    2018-03-01

    The exposure time is a water transport time scale defined as the cumulative amount of time a water parcel spends in the domain of interest regardless of the number of excursions from the domain. Transport time scales are often used to characterize the nutrient removal potential of aquatic systems, but exposure time distribution estimates are scarce for deltaic systems. Here we analyze the controls on exposure time distributions using a hydrodynamic model in two domains: the Wax Lake delta in Louisiana, USA, and an idealized channel-island complex. In particular, we study the effects of river discharge, vegetation, network geometry, and tides and use a simple model for the fractional removal of nitrate. In both domains, we find that channel-island hydrological connectivity significantly affects exposure time distributions and nitrate removal. The relative contributions of the island and channel portions of the delta to the overall exposure time distribution are controlled by island vegetation roughness and network geometry. Tides have a limited effect on the system's exposure time distribution but can introduce significant spatial variability in local exposure times. The median exposure time for the WLD model is 10 h under the conditions tested and water transport within the islands contributes to 37-50% of the network-scale exposure time distribution and 52-73% of the modeled nitrate removal, indicating that islands may account for the majority of nitrate removal in river deltas.

  17. The efficacy of ultrasound treatment as a reversible male contraceptive in the rhesus monkey.

    Science.gov (United States)

    VandeVoort, Catherine A; Tollner, Theodore L

    2012-09-12

    The use of therapeutic ultrasound as a contraceptive approach has involved nonhuman primates as well as rats and dogs. The current study was undertaken to determine whether this treatment could be a method for reversible contraception, using a model with testes size similar to adult humans. Two methods of ultrasound exposure were used, either the transducer probe at the bottom of a cup filled with saline (Cup) or direct application to the surface of the scrotum (Direct). Four adult rhesus (Macaca mulatta) males with normal semen parameters were treated with therapeutic ultrasound at 2.5 W/cm(2) for 30 min. Treatment was given 3 times, one every other day on a Monday-Wednesday-Friday schedule. For each male, semen quality was evaluated a minimum of three times over several months prior to ultrasound exposure and weekly for two months following ultrasound treatment. Semen samples from all males, regardless of exposure method, exhibited a decrease in the percentage of motile sperm following ultrasound treatment. There was an average reduction in motility of 40% the week following treatment. Similarly, curvilinear velocity and the percentage of sperm with a normally shaped flagellum were also reduced in all males following ultrasound treatment. A significant reduction in the total number of sperm in an ejaculate (total sperm count) was only observed in males that received ultrasound via the cup method. Following treatment via the cup method, males exhibited up to a 91.7% decrease in average total sperm count (n = 2). Sperm count did not approach pre-treatment levels until 8 weeks following ultrasound exposure. The sustained reduction in sperm count, percent motility, normal morphology, and sperm vigor with the cup exposure method provides proof of principle that testicular treatment with ultrasound can be an effective contraceptive approach in humans.

  18. The efficacy of ultrasound treatment as a reversible male contraceptive in the rhesus monkey

    Directory of Open Access Journals (Sweden)

    VandeVoort Catherine A

    2012-09-01

    Full Text Available Abstract Background The use of therapeutic ultrasound as a contraceptive approach has involved nonhuman primates as well as rats and dogs. The current study was undertaken to determine whether this treatment could be a method for reversible contraception, using a model with testes size similar to adult humans. Methods Two methods of ultrasound exposure were used, either the transducer probe at the bottom of a cup filled with saline (Cup or direct application to the surface of the scrotum (Direct. Four adult rhesus (Macaca mulatta males with normal semen parameters were treated with therapeutic ultrasound at 2.5 W/cm(2 for 30 min. Treatment was given 3 times, one every other day on a Monday-Wednesday-Friday schedule. For each male, semen quality was evaluated a minimum of three times over several months prior to ultrasound exposure and weekly for two months following ultrasound treatment. Results Semen samples from all males, regardless of exposure method, exhibited a decrease in the percentage of motile sperm following ultrasound treatment. There was an average reduction in motility of 40% the week following treatment. Similarly, curvilinear velocity and the percentage of sperm with a normally shaped flagellum were also reduced in all males following ultrasound treatment. A significant reduction in the total number of sperm in an ejaculate (total sperm count was only observed in males that received ultrasound via the cup method. Following treatment via the cup method, males exhibited up to a 91.7% decrease in average total sperm count (n = 2. Sperm count did not approach pre-treatment levels until 8 weeks following ultrasound exposure. Conclusions The sustained reduction in sperm count, percent motility, normal morphology, and sperm vigor with the cup exposure method provides proof of principle that testicular treatment with ultrasound can be an effective contraceptive approach in humans.

  19. Radiation exposure in nuclear medicine: real-time measurement

    International Nuclear Information System (INIS)

    Sylvain, Iara; Bok, Bernard; X. Bichat University, Paris

    2002-01-01

    French regulations have introduced the use of electronic dosimeters for personnel monitoring of workers. In order to evaluate the exposure from diagnostic procedures to nuclear medicine staff, individual whole-body doses were measured daily with electronic (digital) personal dosimeters during 20 consecutive weeks and correlated with the work load of each day. Personal doses remained always below 20 mu Sv/d under normal working conditions. Radiation exposure levels were highest to tech staff, nurses and stretcher-bearers. The extrapolated annual cumulative doses for all staff remained less than 10% of the maximum legal limit for exposed workers (2 mSv/yr). Electronic dosimeters are not technically justified for routine survey of staff. The high sensitivity and immediate reading of electronic semiconductor dosimeters may become very useful for exposure control under risky working conditions. It may become an important help for optimising radiation protection. (author)

  20. Quantitative contrast enhanced ultrasound of the liver for time intensity curves-Reliability and potential sources of errors.

    Science.gov (United States)

    Ignee, Andre; Jedrejczyk, Maciej; Schuessler, Gudrun; Jakubowski, Wieslaw; Dietrich, Christoph F

    2010-01-01

    Time intensity curves for real-time contrast enhanced low MI ultrasound is a promising technique since it adds objective data to the more subjective conventional contrast enhanced technique. Current developments showed that the amount of uptake in modern targeted therapy strategies correlates with therapy response. Nevertheless no basic research has been done concerning the reliability and validity of the method. Videos sequences of 31 consecutive patients for at least 60s were recorded. Parameters analysed: area under the curve, maximum intensity, mean transit time, perfusion index, time to peak, rise time. The influence of depth, lateral shift as well as size and shape of the region of interest was analysed. The parameters time to peak and rise time showed a good stability in different depths. Overall there was a variation >50% for all other parameters. Mean transit time, time to peak and rise time were stable from 3 to 10cm depths, whereas all other parameters showed only satisfying results at 4-6cm. Time to peak and rise time were stable as well against lateral shifting whereas all other parameters had again variations over 50%. Size and shape of the region of interest did not influence the results. (1) It is important to compare regions of interest, e.g. in a tumour vs. representative parenchyma in the same depths. (2) Time intensity curves should not be analysed in a depth of less than 4cm. (3) The parameters area under the curve, perfusion index and maximum intensity should not be analysed in a depth more than 6cm. (4) Size and shape of a region of interest in liver parenchyma do not affect time intensity curves. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.

  1. Quantitative contrast enhanced ultrasound of the liver for time intensity curves-Reliability and potential sources of errors

    Energy Technology Data Exchange (ETDEWEB)

    Ignee, Andre [Department of Internal Medicine and Diagnostic Imaging, Caritas Hospital, Uhlandstr. 7, 97990 Bad Mergentheim (Germany)], E-mail: andre.ignee@gmx.de; Jedrejczyk, Maciej [Department of Diagnostic Imaging, 2nd Division of Medical Faculty, Medical University, Ul. Kondratowicza 8, 03-242 Warsaw (Poland)], E-mail: mjedrzejczyk@interia.pl; Schuessler, Gudrun [Department of Internal Medicine and Diagnostic Imaging, Caritas Hospital, Uhlandstr. 7, 97990 Bad Mergentheim (Germany)], E-mail: gudrunschuessler@gmx.de; Jakubowski, Wieslaw [Department of Diagnostic Imaging, 2nd Division of Medical Faculty, Medical University, Ul. Kondratowicza 8, 03-242 Warsaw (Poland)], E-mail: ewajbmd@go2.pl; Dietrich, Christoph F. [Department of Internal Medicine and Diagnostic Imaging, Caritas Hospital, Uhlandstr. 7, 97990 Bad Mergentheim (Germany)], E-mail: christoph.dietrich@ckbm.de

    2010-01-15

    Introduction: Time intensity curves for real-time contrast enhanced low MI ultrasound is a promising technique since it adds objective data to the more subjective conventional contrast enhanced technique. Current developments showed that the amount of uptake in modern targeted therapy strategies correlates with therapy response. Nevertheless no basic research has been done concerning the reliability and validity of the method. Patients and methods: Videos sequences of 31 consecutive patients for at least 60 s were recorded. Parameters analysed: area under the curve, maximum intensity, mean transit time, perfusion index, time to peak, rise time. The influence of depth, lateral shift as well as size and shape of the region of interest was analysed. Results: The parameters time to peak and rise time showed a good stability in different depths. Overall there was a variation >50% for all other parameters. Mean transit time, time to peak and rise time were stable from 3 to 10 cm depths, whereas all other parameters showed only satisfying results at 4-6 cm. Time to peak and rise time were stable as well against lateral shifting whereas all other parameters had again variations over 50%. Size and shape of the region of interest did not influence the results. Discussion: (1) It is important to compare regions of interest, e.g. in a tumour vs. representative parenchyma in the same depths. (2) Time intensity curves should not be analysed in a depth of less than 4 cm. (3) The parameters area under the curve, perfusion index and maximum intensity should not be analysed in a depth more than 6 cm. (4) Size and shape of a region of interest in liver parenchyma do not affect time intensity curves.

  2. Quantitative contrast enhanced ultrasound of the liver for time intensity curves-Reliability and potential sources of errors

    International Nuclear Information System (INIS)

    Ignee, Andre; Jedrejczyk, Maciej; Schuessler, Gudrun; Jakubowski, Wieslaw; Dietrich, Christoph F.

    2010-01-01

    Introduction: Time intensity curves for real-time contrast enhanced low MI ultrasound is a promising technique since it adds objective data to the more subjective conventional contrast enhanced technique. Current developments showed that the amount of uptake in modern targeted therapy strategies correlates with therapy response. Nevertheless no basic research has been done concerning the reliability and validity of the method. Patients and methods: Videos sequences of 31 consecutive patients for at least 60 s were recorded. Parameters analysed: area under the curve, maximum intensity, mean transit time, perfusion index, time to peak, rise time. The influence of depth, lateral shift as well as size and shape of the region of interest was analysed. Results: The parameters time to peak and rise time showed a good stability in different depths. Overall there was a variation >50% for all other parameters. Mean transit time, time to peak and rise time were stable from 3 to 10 cm depths, whereas all other parameters showed only satisfying results at 4-6 cm. Time to peak and rise time were stable as well against lateral shifting whereas all other parameters had again variations over 50%. Size and shape of the region of interest did not influence the results. Discussion: (1) It is important to compare regions of interest, e.g. in a tumour vs. representative parenchyma in the same depths. (2) Time intensity curves should not be analysed in a depth of less than 4 cm. (3) The parameters area under the curve, perfusion index and maximum intensity should not be analysed in a depth more than 6 cm. (4) Size and shape of a region of interest in liver parenchyma do not affect time intensity curves.

  3. Two-dimensional Shear Wave Elastography on Conventional Ultrasound Scanners with Time Aligned Sequential Tracking (TAST) and Comb-push Ultrasound Shear Elastography (CUSE)

    OpenAIRE

    Song, Pengfei; Macdonald, Michael C.; Behler, Russell H.; Lanning, Justin D.; Wang, Michael H.; Urban, Matthew W.; Manduca, Armando; Zhao, Heng; Callstrom, Matthew R.; Alizad, Azra; Greenleaf, James F.; Chen, Shigao

    2015-01-01

    Two-dimensional (2D) shear wave elastography presents 2D quantitative shear elasticity maps of tissue, which are clinically useful for both focal lesion detection and diffuse disease diagnosis. Realization of 2D shear wave elastography on conventional ultrasound scanners, however, is challenging due to the low tracking pulse-repetition-frequency (PRF) of these systems. While some clinical and research platforms support software beamforming and plane wave imaging with high PRF, the majority of...

  4. A Numerical Investigation of the Time Reversal Mirror Technique for Trans-skull Brain Cancer Ultrasound Surgery

    Directory of Open Access Journals (Sweden)

    H. Zahedmanesh

    2007-06-01

    Full Text Available Introduction: The medical applications of ultrasound on human brain are highly limited by the phase and amplitude aberrations induced by the heterogeneities of the skull. However, it has been shown that time reversing coupled with amplitude compensation can overcome these aberrations. In this work, a model for 2D simulation of the time reversal mirror technique is proposed to study the possibility of targeting any point within the brain without the need for craniotomy and to calculate the acoustic pressure field and the resulting temperature distribution within the skull and brain during a High Intensity Focused Ultrasound (HIFU transcranial therapy. Materials and Methods: To overcome the sensitivity of the wave pattern to the heterogeneous geometry of the skull, a real MRI derived 2D model is constructed. The model should include the real geometry of brain and skull. The model should also include the couplant medium which has the responsibility of coupling the transducer to the skull for the penetration of ultrasound. The clinical substance used as the couplant is water. The acoustic and thermal parameters are derived from the references. Next, the wave propagation through the skull is computed based on the Helmholtz equation, with a 2D finite element analysis. The acoustic simulation is combined with a 2D thermal diffusion analysis based on Pennes Bioheat equation and the temperature elevation inside the skull and brain is computed. The numerical simulations were performed using the FEMLAB 3.2 software on a PC having 8 GB RAM and a 2.4 MHz dual CPU. Results: It is seen that the ultrasonic waves are exactly focalized at the location where the hydrophone has been previously implanted. There is no penetration into the sinuses and the waves are reflected from their surface because of the high discrepancy between the speed of sound in bone and air.  Under the focal pressure of 2.5 MPa and after 4 seconds of sonication the temperature at the focus

  5. Comparison of Thresholds for Pulmonary Capillary Hemorrhage Induced by Pulsed-wave and B-mode Ultrasound

    Science.gov (United States)

    Miller, Douglas L.; Dou, Chunyan; Raghavendran, Krishnan

    Pulsed ultrasound was found to induce pulmonary capillary hemorrhage (PCH) in mice about 25 years ago but remains a poorly understood risk factor for pulmonary diagnostic ultrasound. In early research using laboratory fixed beam ultrasound, thresholds for PCH had frequency variation from 1-4 MHz similar to the Mechanical Index. In recent research, thresholds for B mode diagnostic ultrasound from 1.5-12 MHz had little dependence on frequency. To compare the diagnostic ultrasound method to laboratory pulsed exposure, thresholds for fixed beam ultrasound were determined using comparable methods at 1.5 and 7.5 MHz. PCH thresholds were lower for simple fixed-beam pulse modes than for B mode and in approximate agreement with early research. However, for comparable timing parameters, PCH thresholds had little dependence on ultrasonic frequency. These findings suggest that the MI may not be directly useful as a dosimetric parameter for safety guidance in pulmonary ultrasound.

  6. Retention of Idioms Following One-Time Exposure

    Science.gov (United States)

    Reuterskiold, Christina; Van Lancker Sidtis, Diana

    2013-01-01

    This study explored retention of idioms and novel (i.e. newly created or grammatically generated) expressions in English-speaking girls following exposure only once during a conversation. Our hypothesis was that idioms, because of their inherent holistic, nonliteral and social characteristics, are acquired differently and more rapidly than novel…

  7. Population models for time-varying pesticide exposure

    NARCIS (Netherlands)

    Jager T; Jong FMW de; Traas TP; LER; SEC

    2007-01-01

    A model has recently been developed at RIVM to predict the effects of variable exposure to pesticides of plant and animal populations in surface water. Before a pesticide is placed on the market, the environmental risk of the substance has to be assessed. This risk is estimated by comparing

  8. A simple exposure-time theory for all time-nonlocal transport formulations and beyond.

    Science.gov (United States)

    Ginn, T. R.; Schreyer, L. G.

    2016-12-01

    Anomalous transport or better put, anomalous non-transport, of solutes or flowing water or suspended colloids or bacteria etc. has been the subject of intense analyses with multiple formulations appearing in scientific literature from hydrology to geomorphology to chemical engineering, to environmental microbiology to mathematical physics. Primary focus has recently been on time-nonlocal mass conservation formulations such as multirate mass transfer, fractional-time advection-dispersion, continuous-time random walks, and dual porosity modeling approaches, that employ a convolution with a memory function to reflect respective conceptual models of delays in transport. These approaches are effective or "proxy" ones that do not always distinguish transport from immobilzation delays, are generally without connection to measurable physicochemical properties, and involve variously fractional calculus, inverse Laplace or Fourier transformations, and/or complex stochastic notions including assumptions of stationarity or ergodicity at the observation scale. Here we show a much simpler approach to time-nonlocal (non-)transport that is free of all these things, and is based on expressing the memory function in terms of a rate of mobilization of immobilized mass that is a function of the continguous time immobilized. Our approach treats mass transfer completely independently from the transport process, and it allows specification of actual immobilization mechanisms or delays. To our surprize we found that for all practical purposes any memory function can be expressed this way, including all of those associated with the multi-rate mass transfer approaches, original powerlaw, different truncated powerlaws, fractional-derivative, etc. More intriguing is the fact that the exposure-time approach can be used to construct heretofore unseen memory functions, e.g., forms that generate oscillating tails of breakthrough curves such as may occur in sediment transport, forms for delay

  9. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... women and their unborn babies. Ultrasound provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as needle biopsies and fluid aspiration. Risks For standard diagnostic ultrasound , there are no known harmful effects on humans. top of page What are the ...

  10. Remotely supported prehospital ultrasound: A feasibility study of real-time image transmission and expert guidance to aid diagnosis in remote and rural communities.

    Science.gov (United States)

    Eadie, Leila; Mulhern, John; Regan, Luke; Mort, Alasdair; Shannon, Helen; Macaden, Ashish; Wilson, Philip

    2017-01-01

    Introduction Our aim is to expedite prehospital assessment of remote and rural patients using remotely-supported ultrasound and satellite/cellular communications. In this paradigm, paramedics are remotely-supported ultrasound operators, guided by hospital-based specialists, to record images before receiving diagnostic advice. Technology can support users in areas with little access to medical imaging and suboptimal communications coverage by connecting to multiple cellular networks and/or satellites to stream live ultrasound and audio-video. Methods An ambulance-based demonstrator system captured standard trauma and novel transcranial ultrasound scans from 10 healthy volunteers at 16 locations across the Scottish Highlands. Volunteers underwent brief scanning training before receiving expert guidance via the communications link. Ultrasound images were streamed with an audio/video feed to reviewers for interpretation. Two sessions were transmitted via satellite and 21 used cellular networks. Reviewers rated image and communication quality, and their utility for diagnosis. Transmission latency and bandwidth were recorded, and effects of scanner and reviewer experience were assessed. Results Appropriate views were provided in 94% of the simulated trauma scans. The mean upload rate was 835/150 kbps and mean latency was 114/2072 ms for cellular and satellite networks, respectively. Scanning experience had a significant impact on time to achieve a diagnostic image, and review of offline scans required significantly less time than live-streamed scans. Discussion This prehospital ultrasound system could facilitate early diagnosis and streamlining of treatment pathways for remote emergency patients, being particularly applicable in rural areas worldwide with poor communications infrastructure and extensive transport times.

  11. Imaging of the Achilles tendon in spondyloarthritis: a comparison of ultrasound and conventional, short and ultrashort echo time MRI with and without intravenous contrast

    International Nuclear Information System (INIS)

    Hodgson, R.J.; Emery, P.; Grainger, A.J.; O'Connor, P.J.; Evans, R.; Coates, L.; Marzo-Ortega, H.; Helliwell, P.; McGonagle, D.; Robson, M.D.

    2011-01-01

    To compare conventional MRI, ultrashort echo time MRI and ultrasound for assessing the extent of tendon abnormalities in spondyloarthritis. 25 patients with spondyloarthritis and Achilles symptoms were studied with MRI and ultrasound. MR images of the Achilles tendon were acquired using T1-weighted spin echo, gradient echo and ultrashort echo time (UTE) sequences with echo times (TE) between 0.07 and 16 ms, before and after intravenous contrast medium. Greyscale and power Doppler ultrasound were also performed. The craniocaudal extent of imaging abnormalities measured by a consultant musculoskeletal radiologist was compared between the different techniques. Abnormalities were most extensive on spoiled gradient echo images with TE=2 ms. Contrast enhancement after intravenous gadolinium was greatest on the UTE images (TE=0.07 ms). Fewer abnormalities were demonstrated using unenhanced UTE. Abnormalities were more extensive on MRI than ultrasound. Contrast enhancement was more extensive than power Doppler signal. 3D spoiled gradient echo images with an echo time of 2 ms demonstrate more extensive tendon abnormalities than the other techniques in spondyloarthritis. Abnormalities of vascularity are best demonstrated on enhanced ultrashort echo time images. (orig.)

  12. Focused ultrasound in ophthalmology

    Directory of Open Access Journals (Sweden)

    Silverman RH

    2016-09-01

    Full Text Available Ronald H Silverman1,2 1Department of Ophthalmology, Columbia University Medical Center, 2F.L. Lizzi Center for Biomedical Engineering, Riverside Research, New York, NY, USA Abstract: The use of focused ultrasound to obtain diagnostically significant information about the eye goes back to the 1950s. This review describes the historical and technological development of ophthalmic ultrasound and its clinical application and impact. Ultrasound, like light, can be focused, which is crucial for formation of high-resolution, diagnostically useful images. Focused, single-element, mechanically scanned transducers are most common in ophthalmology. Specially designed transducers have been used to generate focused, high-intensity ultrasound that through thermal effects has been used to treat glaucoma (via cilio-destruction, tumors, and other pathologies. Linear and annular transducer arrays offer synthetic focusing in which precise timing of the excitation of independently addressable array elements allows formation of a converging wavefront to create a focus at one or more programmable depths. Most recently, linear array-based plane-wave ultrasound, in which the array emits an unfocused wavefront and focusing is performed solely on received data, has been demonstrated for imaging ocular anatomy and blood flow. While the history of ophthalmic ultrasound extends back over half-a-century, new and powerful technologic advances continue to be made, offering the prospect of novel diagnostic capabilities. Keywords: ophthalmic ultrasound, ultrasound biomicroscopy (UBM, high-intensity focused ultrasound (HIFU, ultrafast imaging, Doppler imaging 

  13. Real-time registration of 3D to 2D ultrasound images for image-guided prostate biopsy.

    Science.gov (United States)

    Gillies, Derek J; Gardi, Lori; De Silva, Tharindu; Zhao, Shuang-Ren; Fenster, Aaron

    2017-09-01

    During image-guided prostate biopsy, needles are targeted at tissues that are suspicious of cancer to obtain specimen for histological examination. Unfortunately, patient motion causes targeting errors when using an MR-transrectal ultrasound (TRUS) fusion approach to augment the conventional biopsy procedure. This study aims to develop an automatic motion correction algorithm approaching the frame rate of an ultrasound system to be used in fusion-based prostate biopsy systems. Two modes of operation have been investigated for the clinical implementation of the algorithm: motion compensation using a single user initiated correction performed prior to biopsy, and real-time continuous motion compensation performed automatically as a background process. Retrospective 2D and 3D TRUS patient images acquired prior to biopsy gun firing were registered using an intensity-based algorithm utilizing normalized cross-correlation and Powell's method for optimization. 2D and 3D images were downsampled and cropped to estimate the optimal amount of image information that would perform registrations quickly and accurately. The optimal search order during optimization was also analyzed to avoid local optima in the search space. Error in the algorithm was computed using target registration errors (TREs) from manually identified homologous fiducials in a clinical patient dataset. The algorithm was evaluated for real-time performance using the two different modes of clinical implementations by way of user initiated and continuous motion compensation methods on a tissue mimicking prostate phantom. After implementation in a TRUS-guided system with an image downsampling factor of 4, the proposed approach resulted in a mean ± std TRE and computation time of 1.6 ± 0.6 mm and 57 ± 20 ms respectively. The user initiated mode performed registrations with in-plane, out-of-plane, and roll motions computation times of 108 ± 38 ms, 60 ± 23 ms, and 89 ± 27 ms, respectively, and corresponding

  14. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... terms of the distance traveled per unit of time, rather than as a color picture. It can ...

  15. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... ultrasound images are captured in real-time, they can show the structure and movement of the body's ... time, rather than as a color picture. It can also convert blood flow information into a distinctive ...

  16. Real-time target tracking of soft tissues in 3D ultrasound images based on robust visual information and mechanical simulation.

    Science.gov (United States)

    Royer, Lucas; Krupa, Alexandre; Dardenne, Guillaume; Le Bras, Anthony; Marchand, Eric; Marchal, Maud

    2017-01-01

    In this paper, we present a real-time approach that allows tracking deformable structures in 3D ultrasound sequences. Our method consists in obtaining the target displacements by combining robust dense motion estimation and mechanical model simulation. We perform evaluation of our method through simulated data, phantom data, and real-data. Results demonstrate that this novel approach has the advantage of providing correct motion estimation regarding different ultrasound shortcomings including speckle noise, large shadows and ultrasound gain variation. Furthermore, we show the good performance of our method with respect to state-of-the-art techniques by testing on the 3D databases provided by MICCAI CLUST'14 and CLUST'15 challenges. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Enabling real-time ultrasound imaging of soft tissue mechanical properties by simplification of the shear wave motion equation.

    Science.gov (United States)

    Engel, Aaron J; Bashford, Gregory R

    2015-08-01

    Ultrasound based shear wave elastography (SWE) is a technique used for non-invasive characterization and imaging of soft tissue mechanical properties. Robust estimation of shear wave propagation speed is essential for imaging of soft tissue mechanical properties. In this study we propose to estimate shear wave speed by inversion of the first-order wave equation following directional filtering. This approach relies on estimation of first-order derivatives which allows for accurate estimations using smaller smoothing filters than when estimating second-order derivatives. The performance was compared to three current methods used to estimate shear wave propagation speed: direct inversion of the wave equation (DIWE), time-to-peak (TTP) and cross-correlation (CC). The shear wave speed of three homogeneous phantoms of different elastic moduli (gelatin by weight of 5%, 7%, and 9%) were measured with each method. The proposed method was shown to produce shear speed estimates comparable to the conventional methods (standard deviation of measurements being 0.13 m/s, 0.05 m/s, and 0.12 m/s), but with simpler processing and usually less time (by a factor of 1, 13, and 20 for DIWE, CC, and TTP respectively). The proposed method was able to produce a 2-D speed estimate from a single direction of wave propagation in about four seconds using an off-the-shelf PC, showing the feasibility of performing real-time or near real-time elasticity imaging with dedicated hardware.

  18. Real-Time Ultrasound/MRI Fusion for Suprasacral Parallel Shift Approach to Lumbosacral Plexus Blockade and Analysis of Injectate Spread

    DEFF Research Database (Denmark)

    Strid, Jennie Maria Christin; Pedersen, Erik Morre; Al-Karradi, Sinan Naseer Hussain

    2017-01-01

    Fused real-time ultrasound and magnetic resonance imaging (MRI) may be used to improve the accuracy of advanced image guided procedures. However, its use in regional anesthesia is practically nonexistent. In this randomized controlled crossover trial, we aim to explore effectiveness, procedure-re...

  19. The Role of Airway and Endobronchial Ultrasound in Perioperative Medicine

    Directory of Open Access Journals (Sweden)

    Jiri Votruba

    2015-01-01

    Full Text Available Recent years have witnessed an increased use of ultrasound in evaluation of the airway and the lower parts of the respiratory system. Ultrasound examination is fast and reliable and can be performed at the bedside and does not carry the risk of exposure to ionizing radiation. Apart from use in diagnostics it may also provide safe guidance for invasive and semi-invasive procedures. Ultrasound examination of the oral cavity structures, epiglottis, vocal cords, and subglottic space may help in the prediction of difficult intubation. Preoperative ultrasound may diagnose vocal cord palsy or deviation or stenosis of the trachea. Ultrasonography can also be used for confirmation of endotracheal tube, double-lumen tube, or laryngeal mask placement. This can be achieved by direct examination of the tube inside the trachea or by indirect methods evaluating lung movements. Postoperative airway ultrasound may reveal laryngeal pathology or subglottic oedema. Conventional ultrasound is a reliable real-time navigational tool for emergency cricothyrotomy or percutaneous dilational tracheostomy. Endobronchial ultrasound is a combination of bronchoscopy and ultrasonography and is used for preoperative examination of lung cancer and solitary pulmonary nodules. The method is also useful for real-time navigated biopsies of such pathological structures.

  20. Joint analysis of French and Czech uranium miners: lung cancer risk at low radon exposure rates and modifying effects of time since exposure and age at exposure

    International Nuclear Information System (INIS)

    Ladislav Tomasek; Agnes Rogel; Margot Tirmarche; Dominique Laurier

    2006-01-01

    The present analysis was conducted in the frame of European project 'Quantification of lung cancer risk after low radon exposure and low exposure rate: synthesis from epidemiologic and experimental data'. The overall goal of the project related to uranium miners was the evaluation of lung cancer dose-response relationship and of dose rate effects among European uranium miners exposed to low doses and low dose rates of radon decay products. In addition, modifying factors like attained age, age at exposure and time since exposure were investigated. The joint analysis of French and Czech uranium miners was conducted mainly in order to increase the statistical power and to allow a more detailed description of the variation of dose-response relationship in time. (N.C.)

  1. Joint analysis of French and Czech uranium miners: lung cancer risk at low radon exposure rates and modifying effects of time since exposure and age at exposure

    Energy Technology Data Exchange (ETDEWEB)

    Ladislav Tomasek [National Radiation Protection Institute, Prague (Czech Republic); Agnes Rogel; Margot Tirmarche; Dominique Laurier [Institut de Radioprotection et de Surete Nucleaire, Fontenay-aux-Roses (France)

    2006-07-01

    The present analysis was conducted in the frame of European project 'Quantification of lung cancer risk after low radon exposure and low exposure rate: synthesis from epidemiologic and experimental data'. The overall goal of the project related to uranium miners was the evaluation of lung cancer dose-response relationship and of dose rate effects among European uranium miners exposed to low doses and low dose rates of radon decay products. In addition, modifying factors like attained age, age at exposure and time since exposure were investigated. The joint analysis of French and Czech uranium miners was conducted mainly in order to increase the statistical power and to allow a more detailed description of the variation of dose-response relationship in time. (N.C.)

  2. Optimal transcostal high-intensity focused ultrasound with combined real-time 3D movement tracking and correction

    International Nuclear Information System (INIS)

    Marquet, F; Aubry, J F; Pernot, M; Fink, M; Tanter, M

    2011-01-01

    Recent studies have demonstrated the feasibility of transcostal high intensity focused ultrasound (HIFU) treatment in liver. However, two factors limit thermal necrosis of the liver through the ribs: the energy deposition at focus is decreased by the respiratory movement of the liver and the energy deposition on the skin is increased by the presence of highly absorbing bone structures. Ex vivo ablations were conducted to validate the feasibility of a transcostal real-time 3D movement tracking and correction mode. Experiments were conducted through a chest phantom made of three human ribs immersed in water and were placed in front of a 300 element array working at 1 MHz. A binarized apodization law introduced recently in order to spare the rib cage during treatment has been extended here with real-time electronic steering of the beam. Thermal simulations have been conducted to determine the steering limits. In vivo 3D-movement detection was performed on pigs using an ultrasonic sequence. The maximum error on the transcostal motion detection was measured to be 0.09 ± 0.097 mm on the anterior–posterior axis. Finally, a complete sequence was developed combining real-time 3D transcostal movement correction and spiral trajectory of the HIFU beam, allowing the system to treat larger areas with optimized efficiency. Lesions as large as 1 cm in diameter have been produced at focus in excised liver, whereas no necroses could be obtained with the same emitted power without correcting the movement of the tissue sample.

  3. Is it time to include point-of-care ultrasound in general surgery training? A review to stimulate discussion.

    Science.gov (United States)

    Mollenkopf, Maximilian; Tait, Noel

    2013-12-01

    Point-of-care ultrasound scanning or POCUS is a focused ultrasound (US) scan, performed by non-imaging clinicians during physical examination, an invasive procedure or surgery. As this technology becomes cheaper, smaller and easier to use, its scope for use by surgeons grows, a trend that may generate a gap between use and training. Opportunities for enhanced general surgery skill sets may be reduced unless consideration is given to inclusion of POCUS in general surgery training. To stimulate discussion regarding inclusion of POCUS in the general surgery curriculum; to resource this discussion with an overview of current trends and issues around POCUS; and to discuss concerns and controversies that may arise if POCUS was adopted into general surgery training. A literature search was performed using PUBMED, MEDLINE, Google and Google Scholar, using the terms 'ultrasound', 'point-of-care-ultrasound', 'bedside ultrasound', 'portable ultrasound' and 'hand-held ultrasound'. Literature, references and non-literature resources found were reviewed for relevance to US education in general surgery. Increasingly, medical students are graduating with basic POCUS skills. Specialty-specific uses of POCUS are proliferating. Training and assessment resources are not keeping up, in accessibility or standardization. A learned surgical college led training and accreditation process would require aligned education in anatomy and US technology and collaboration with the specialist imaging community to ensure appropriate standards are clarified and met. Research is also required into how general surgery trainees can best achieve and maintain POCUS competence. © 2013 Royal Australasian College of Surgeons.

  4. How to statistically analyze nano exposure measurement results: Using an ARIMA time series approach

    NARCIS (Netherlands)

    Klein Entink, R.H.; Fransman, W.; Brouwer, D.H.

    2011-01-01

    Measurement strategies for exposure to nano-sized particles differ from traditional integrated sampling methods for exposure assessment by the use of real-time instruments. The resulting measurement series is a time series, where typically the sequential measurements are not independent from each

  5. Measurement of ventricular function using Doppler ultrasound

    International Nuclear Information System (INIS)

    Teague, S.M.

    1986-01-01

    Doppler has wide application in the evaluation of valvular heart disease. The need to know ventricular function is a much more common reason for an echocardiographic evaluation. Interestingly, Doppler examinations can assess ventricular function from many perspectives. Description of ventricular function entails measurement of the timing, rate and volume of ventricular filling and ejection. Doppler ultrasound examination reveals all of these aspects of ventricular function noninvasively, simply, and without great expense or radiation exposure, as described in this chapter

  6. Lagged kernel machine regression for identifying time windows of susceptibility to exposures of complex mixtures.

    Science.gov (United States)

    Liu, Shelley H; Bobb, Jennifer F; Lee, Kyu Ha; Gennings, Chris; Claus Henn, Birgit; Bellinger, David; Austin, Christine; Schnaas, Lourdes; Tellez-Rojo, Martha M; Hu, Howard; Wright, Robert O; Arora, Manish; Coull, Brent A

    2018-07-01

    The impact of neurotoxic chemical mixtures on children's health is a critical public health concern. It is well known that during early life, toxic exposures may impact cognitive function during critical time intervals of increased vulnerability, known as windows of susceptibility. Knowledge on time windows of susceptibility can help inform treatment and prevention strategies, as chemical mixtures may affect a developmental process that is operating at a specific life phase. There are several statistical challenges in estimating the health effects of time-varying exposures to multi-pollutant mixtures, such as: multi-collinearity among the exposures both within time points and across time points, and complex exposure-response relationships. To address these concerns, we develop a flexible statistical method, called lagged kernel machine regression (LKMR). LKMR identifies critical exposure windows of chemical mixtures, and accounts for complex non-linear and non-additive effects of the mixture at any given exposure window. Specifically, LKMR estimates how the effects of a mixture of exposures change with the exposure time window using a Bayesian formulation of a grouped, fused lasso penalty within a kernel machine regression (KMR) framework. A simulation study demonstrates the performance of LKMR under realistic exposure-response scenarios, and demonstrates large gains over approaches that consider each time window separately, particularly when serial correlation among the time-varying exposures is high. Furthermore, LKMR demonstrates gains over another approach that inputs all time-specific chemical concentrations together into a single KMR. We apply LKMR to estimate associations between neurodevelopment and metal mixtures in Early Life Exposures in Mexico and Neurotoxicology, a prospective cohort study of child health in Mexico City.

  7. Radiation exposure in nuclear medicine: real-time measurement

    Directory of Open Access Journals (Sweden)

    Iara Sylvain

    2002-09-01

    Full Text Available French regulations have introduced the use of electronic dosimeters for personal monitoring of workers. In order to evaluate the exposure from diagnostic procedures to nuclear medicine staff, individual whole-body doses were measured daily with electronic (digital personal dosimeters during 20 consecutive weeks and correlated with the work load of each day. Personal doses remained always below 20 µSv/d under normal working conditions. Radiation exposure levels were highest to tech staff, nurses and stretcher-bearers. The extrapolated annual cumulative doses for all staff remained less than 10 % of the maximum legal limit for exposed workers (2 mSv/yr. Electronic dosimeters are not technically justified for routine survey of staff. The high sensitivity and immediate reading of electronic semiconductor dosimeters may become very useful for exposure control under risky working conditions. It may become an important help for optimising radiation protection.A legislação francesa introduziu o uso de dosímetros eletrônicos para monitoração da exposição do trabalhador. Afim de avaliar a exposição do trabalhador proveniente de exames diagnósticos em medicina nuclear, doses individuais do corpo inteiro foram medidas diariamente com dosímetros eletrônicos (digitais durante 20 semanas consecutivas e correlatas com as atividades de trabalho de cada dia. As doses foram sempre inferiores à 20 µSv por dia em condições normais de trabalho. Os níveis de exposição de radiação mais elevados foram para os enfermeiros, manipuladores e maqueiros. A extrapolação da dose anual para todos os trabalhadores foi menos que 10 % do limite máximo legal para os trabalhadores expostos (2 mSv/ano. Dosímetros eletrônicos não são tecnicamente justificados para a o controle de rotina da exposição dos trabalhadores, mas a alta sensibilidade e a leitura imediata desses dosímetros podem vir a serem muito úteis para o controle da exposição em condi

  8. Effects of post exposure bake temperature and exposure time on SU-8 nanopattern obtained by electron beam lithography

    Science.gov (United States)

    Yasui, Manabu; Kazawa, Elito; Kaneko, Satoru; Takahashi, Ryo; Kurouchi, Masahito; Ozawa, Takeshi; Arai, Masahiro

    2014-11-01

    SU-8 is a photoresist imaged using UV rays. However, we investigated the characteristics of an SU-8 nanopattern obtained by electron beam lithography (EBL). In particular, we studied the relationship between post-exposure bake (PEB) temperature and exposure time on an SU-8 nanopattern with a focus on phase transition temperature. SU-8 residue was formed by increasing both PEB temperature and exposure time. To prevent the formation of this, Monte Carlo simulation was performed; the results of such simulation showed that decreasing the thickness of SU-8 can reduce the amount of residue from the SU-8 nanopattern. We confirmed that decreasing the thickness of SU-8 can also prevent the formation of residue from the SU-8 nanopattern with EBL.

  9. Ultrasound -- Pelvis

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    Full Text Available ... diagnose symptoms experienced by women such as: pelvic pain abnormal vaginal bleeding other menstrual problems Ultrasound exams ... pelvic ultrasound can help evaluate: pelvic masses pelvic pain ambiguous genitalia and anomalies of pelvic organs early ...

  10. Ultrasound -- Pelvis

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    Full Text Available ... size, shape and consistency (whether the object is solid or filled with fluid). In medicine, ultrasound is ... ultrasound, measures the direction and speed of blood cells as they move through vessels. The movement of ...

  11. Prostate Ultrasound

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    Full Text Available ... pictures of a man’s prostate gland and to help diagnose symptoms such as difficulty urinating or an ... Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Prostate ultrasound, ...

  12. Ultrasound -- Pelvis

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    Full Text Available ... by women such as: pelvic pain abnormal vaginal bleeding other menstrual problems Ultrasound exams also help identify: ... fibroids cancer, especially in patients with abnormal uterine bleeding Some physicians also use 3-D ultrasound or ...

  13. Ultrasound -- Pelvis

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    Full Text Available ... internal organs, as well as blood flowing through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. There are three types of pelvic ultrasound: abdominal ( transabdominal ) vaginal ( transvaginal / endovaginal ) ...

  14. Ultrasound -- Pelvis

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    Full Text Available ... There are three types of pelvic ultrasound: abdominal, vaginal (for women), and rectal (for men). These exams ... are three types of pelvic ultrasound: abdominal ( transabdominal ) vaginal ( transvaginal / endovaginal ) for women rectal ( transrectal ) for men ...

  15. Ultrasound -- Pelvis

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    Full Text Available ... the procedure? In women, a pelvic ultrasound is most often performed to evaluate the: uterus cervix ovaries ... page How is the procedure performed? Transabdominal: For most ultrasound exams, you will be positioned lying face- ...

  16. Ultrasound -- Pelvis

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    Full Text Available ... is used to evaluate the: bladder seminal vesicles prostate Transrectal ultrasound, a special study usually done to provide detailed evaluation of the prostate gland, involves inserting a specialized ultrasound transducer into ...

  17. Ultrasound -- Pelvis

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    Full Text Available ... Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding ... questions or for a referral to a radiologist or other physician. To locate a medical imaging or radiation oncology provider in your community, you ...

  18. Prostate Ultrasound

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    Full Text Available ... top of page What are the benefits vs. risks? Benefits Ultrasound is widely available, easy-to-use ... procedures such as needle biopsies and fluid aspiration. Risks For standard diagnostic ultrasound , there are no known ...

  19. Ultrasound -- Pelvis

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    Full Text Available ... ovarian cysts and uterine fibroids ovarian or uterine cancers A transvaginal ultrasound is usually performed to view the endometrium (the lining of the uterus) and the ovaries. Transvaginal ultrasound also evaluates the myometrium (muscular walls ...

  20. Prostate Ultrasound

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    Full Text Available ... those sound waves to create an image. Ultrasound examinations do not use ionizing radiation (as used in ... abnormal masses, such as tumors. In an ultrasound examination, a transducer both sends the sound waves into ...

  1. Ultrasound -- Pelvis

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    Full Text Available ... needles are used to extract a sample of cells from organs for laboratory testing. Doppler ultrasound images ... ultrasound, measures the direction and speed of blood cells as they move through vessels. The movement of ...

  2. Ultrasound -- Pelvis

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    Full Text Available ... image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is no ... structure and movement of the body's internal organs, as well as blood flowing through blood vessels. Ultrasound ...

  3. Prostate Ultrasound

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    Full Text Available ... to-use and less expensive than other imaging methods. Ultrasound imaging uses no ionizing radiation. Ultrasound scanning ... radiation oncology provider in your community, you can search the ACR-accredited facilities database . This website does ...

  4. Ultrasound -- Pelvis

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    Full Text Available ... Imaging? Ultrasound waves are disrupted by air or gas; therefore ultrasound is not an ideal imaging technique ... page Additional Information and Resources RTAnswers.org Radiation Therapy for Gynecologic Cancers Radiation Therapy for Prostate Cancer ...

  5. Prostate Ultrasound

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    Full Text Available ... of page What will I experience during and after the procedure? Ultrasound exams in which the transducer ... in the sperm or urine following the procedure. After an ultrasound examination, you should be able to ...

  6. Ultrasound -- Pelvis

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    Full Text Available ... investigation of the uterine cavity . Three-dimensional (3-D) ultrasound permits evaluation of the uterus and ovaries ... abnormal uterine bleeding Some physicians also use 3-D ultrasound or sonohysterography for patients with infertility. In ...

  7. Prostate Ultrasound

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    Full Text Available ... and produces pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound ... from the probe through the gel into the body. The transducer collects the sounds that bounce back ...

  8. Ultrasound -- Pelvis

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    Full Text Available ... and produces pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound ... from the probe through the gel into the body. The transducer collects the sounds that bounce back ...

  9. Ultrasound -- Pelvis

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    Full Text Available ... object is solid or filled with fluid). In medicine, ultrasound is used to detect changes in appearance, ... have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Sonohysterography Ultrasound - ...

  10. Obstetrical Ultrasound

    Science.gov (United States)

    ... heartbeat can be seen as an ongoing ultrasound movie. Ultrasound devices also use Doppler, a special application ... the possible charges you will incur. Web page review process: This Web page is reviewed regularly by ...

  11. Ultrasound -- Pelvis

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    Full Text Available ... insertion. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Sonohysterography Ultrasound - ...

  12. Ultrasound -- Pelvis

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    Full Text Available ... menstrual problems Ultrasound exams also help identify: palpable masses such as ovarian cysts and uterine fibroids ovarian ... In children, pelvic ultrasound can help evaluate: pelvic masses pelvic pain ambiguous genitalia and anomalies of pelvic ...

  13. Prostate Ultrasound

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    Full Text Available ... Ultrasound is safe, noninvasive, and does not use ionizing radiation. This procedure requires little to no special preparation. ... create an image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is ...

  14. Ultrasound -- Pelvis

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    Full Text Available ... Ultrasound is safe, noninvasive and does not use ionizing radiation. This procedure requires little to no special preparation. ... create an image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is ...

  15. Ultrasound -- Pelvis

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    Full Text Available ... and development of an embryo or fetus during pregnancy. See the Obstetrical Ultrasound page for more information . ... object is solid or filled with fluid). In medicine, ultrasound is used to detect changes in appearance, ...

  16. Ultrasound -- Pelvis

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    Full Text Available ... ultrasound: abdominal, vaginal (for women), and rectal (for men). These exams are frequently used to evaluate the ... vaginal ( transvaginal / endovaginal ) for women rectal ( transrectal ) for men A Doppler ultrasound exam may be part of ...

  17. Children's (Pediatric) Abdominal Ultrasound Imaging

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    Full Text Available ... not use ionizing radiation, has no known harmful effects, and is particularly valuable for ... is no radiation exposure to the patient. Because ultrasound images are captured ...

  18. Real-Time 3-Dimensional Ultrasound-Assisted Infraclavicular Brachial Plexus Catheter Placement: Implications of a New Technology

    Directory of Open Access Journals (Sweden)

    Steven R. Clendenen

    2010-01-01

    Full Text Available Background. There are a variety of techniques for targeting placement of an infraclavicular blockade; these include eliciting paresthesias, nerve stimulation, and 2-dimensional (2D ultrasound (US guidance. Current 2D US allows direct visualization of a “flat” image of the advancing needle and neurovascular structures but without the ability to extensively analyze multidimensional data and allow for real-time manipulation. Three-dimensional (3D ultrasonography has gained popularity and usefulness in many clinical specialties such as obstetrics and cardiology. We describe some of the potential clinical applications of 3D US in regional anesthesia. Methods. This case represents an infraclavicular catheter placement facilitated by 3D US, which demonstrates 360-degree spatial relationships of the entire anatomic region. Results. The block needle, peripheral nerve catheter, and local anesthetic diffusion were observed in multiple planes of view without manipulation of the US probe. Conclusion. Advantages of 3D US may include the ability to confirm correct needle and catheter placement prior to the injection of local anesthetic. The spread of local anesthetic along the length of the nerve can be easily observed while manipulating the 3D images in real-time by simply rotating the trackball on the US machine to provide additional information that cannot be identified with 2D US alone.

  19. Ultrasound -- Pelvis

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    Full Text Available ... transducer sends out high-frequency sound waves (that the human ear cannot hear) into the body and then ... ultrasound , there are no known harmful effects on humans. top of page What are the limitations of Pelvic Ultrasound Imaging? Ultrasound waves are ...

  20. Pulsed cavitational ultrasound for non-invasive chordal cutting guided by real-time 3D echocardiography.

    Science.gov (United States)

    Villemain, Olivier; Kwiecinski, Wojciech; Bel, Alain; Robin, Justine; Bruneval, Patrick; Arnal, Bastien; Tanter, Mickael; Pernot, Mathieu; Messas, Emmanuel

    2016-10-01

    Basal chordae surgical section has been shown to be effective in reducing ischaemic mitral regurgitation (IMR). Achieving this section by non-invasive mean can considerably decrease the morbidity of this intervention on already infarcted myocardium. We investigated in vitro and in vivo the feasibility and safety of pulsed cavitational focused ultrasound (histotripsy) for non-invasive chordal cutting guided by real-time 3D echocardiography. Experiments were performed on 12 sheep hearts, 5 in vitro on explanted sheep hearts and 7 in vivo on beating sheep hearts. In vitro, the mitral valve (MV) apparatus including basal and marginal chordae was removed and fixed on a holder in a water tank. High-intensity ultrasound pulses were emitted from the therapeutic device (1-MHz focused transducer, pulses of 8 µs duration, peak negative pressure of 17 MPa, repetition frequency of 100 Hz), placed at a distance of 64 mm under 3D echocardiography guidance. In vivo, after sternotomy, the same therapeutic device was applied on the beating heart. We analysed MV coaptation and chordae by real-time 3D echocardiography before and after basal chordal cutting. After sacrifice, the MV apparatus were harvested for anatomical and histological post-mortem explorations to confirm the section of the chordae. In vitro, all chordae were completely cut after a mean procedure duration of 5.5 ± 2.5 min. The procedure duration was found to increase linearly with the chordae diameter. In vivo, the central basal chordae of the anterior leaflet were completely cut. The mean procedure duration was 20 ± 9 min (min = 14, max = 26). The sectioned chordae was visible on echocardiography, and MV coaptation remained normal with no significant mitral regurgitation. Anatomical and histological post-mortem explorations of the hearts confirmed the section of the chordae. Histotripsy guided by 3D echo achieved successfully to cut MV chordae in vitro and in vivo in beating heart. We hope that this technique will

  1. Theoretical study of time-dependent, ultrasound-induced acoustic streaming in microchannels.

    Science.gov (United States)

    Muller, Peter Barkholt; Bruus, Henrik

    2015-12-01

    Based on first- and second-order perturbation theory, we present a numerical study of the temporal buildup and decay of unsteady acoustic fields and acoustic streaming flows actuated by vibrating walls in the transverse cross-sectional plane of a long straight microchannel under adiabatic conditions and assuming temperature-independent material parameters. The unsteady streaming flow is obtained by averaging the time-dependent velocity field over one oscillation period, and as time increases, it is shown to converge towards the well-known steady time-averaged solution calculated in the frequency domain. Scaling analysis reveals that the acoustic resonance builds up much faster than the acoustic streaming, implying that the radiation force may dominate over the drag force from streaming even for small particles. However, our numerical time-dependent analysis indicates that pulsed actuation does not reduce streaming significantly due to its slow decay. Our analysis also shows that for an acoustic resonance with a quality factor Q, the amplitude of the oscillating second-order velocity component is Q times larger than the usual second-order steady time-averaged velocity component. Consequently, the well-known criterion v(1)≪c(s) for the validity of the perturbation expansion is replaced by the more restrictive criterion v(1)≪c(s)/Q. Our numerical model is available as supplemental material in the form of comsol model files and matlab scripts.

  2. Degradation behavior of limestone concrete under limited time sodium exposure

    International Nuclear Information System (INIS)

    Das, S.K.; Sharma, A.K.; Ramesh, S.S.; Parida, F.C.; Kasinathan, N.; Chellapandi, P.

    2009-01-01

    Adequate safety measures are taken during design, fabrication, construction and operation of liquid sodium cooled fast breeder reactor (FBR). However, possibility of sodium leak from secondary heat transport circuits of FBR has not been completely ruled out. In the areas housing sodium pipelines such as Steam Generator Building (SGB), spilled liquid sodium not only reacts with air causing fire but also interacts with structural concrete resulting in its degradation. The structural concrete can be protected from sodium attack using sodium resistant sacrificial concrete layer or steel/refractory liners. Moreover, design and construction of sloping floor with sodium collection pit helps in minimizing the mass of sodium accumulated on the floor and exposure period. Sacrificial concrete layer on the structural concrete should meet key factors like economy, castability, easy removal of affected concrete in the event of a sodium fire and disposability of debris apart from its good resistance against hot burning sodium. Present study is directed towards testing of limestone concrete blocks (made out of 13% ordinary portland cement, 8% water, 48% coarse limestone and 31 % fine limestone aggregates)

  3. Duration and Timing of Exposure to Neighborhood Poverty and the Risk of Adolescent Parenthood

    Science.gov (United States)

    Wodtke, Geoffrey T.

    2013-01-01

    Theory suggests that the impact of neighborhood poverty depends on both the duration and timing of exposure. Previous research, however, does not properly analyze the sequence of neighborhoods to which children are exposed throughout the early life course. This study investigates the effects of different longitudinal patterns of exposure to disadvantaged neighborhoods on the risk of adolescent parenthood. It follows a cohort of children in the PSID from age 4 to 19 and uses novel methods for time-varying exposures that overcome critical limitations of conventional regression when selection processes are dynamic. Results indicate that sustained exposure to poor neighborhoods substantially increases the risk of becoming a teen parent and that exposure to neighborhood poverty during adolescence may be more consequential than exposure earlier during childhood. PMID:23720166

  4. High-frequency ultrasound-responsive block copolymer micelle.

    Science.gov (United States)

    Wang, Jie; Pelletier, Maxime; Zhang, Hongji; Xia, Hesheng; Zhao, Yue

    2009-11-17

    Micelles of a diblock copolymer composed of poly(ethylene oxide) and poly(2-tetrahydropyranyl methacrylate) (PEO-b-PTHPMA) in aqueous solution could be disrupted by high-frequency ultrasound (1.1 MHz). It was found that, upon exposure to a high-intensity focused ultrasound (HIFU) beam at room temperature, the pH value of the micellar solution decreased over irradiation time. The infrared spectroscopic analysis of solid block copolymer samples collected from the ultrasound irradiated micellar solution revealed the formation of carboxylic acid dimers and hydroxyl groups. These characterization results suggest that the high-frequency HIFU beam could induce the hydrolysis reaction of THPMA at room temperature resulting in the cleavage of THP groups. The disruption of PEO-b-PTHPMA micelles by ultrasound was investigated by using dynamic light scattering, atomic force microscopy, and fluorescence spectroscopy. On the basis of the pH change, it was found that the disruption process was determined by a number of factors such as the ultrasound power, the micellar solution volume and the location of the focal spot of the ultrasound beam. This study shows the potential to develop ultrasound-sensitive block copolymer micelles by having labile chemical bonds in the polymer structure, and to use the high-frequency HIFU to trigger a chemical reaction for the disruption of micelles.

  5. Influence of luting agents on time required for cast post removal by ultrasound: an in vitro study

    Directory of Open Access Journals (Sweden)

    Janir Alves Soares

    2009-06-01

    Full Text Available OBJECTIVE: This in vitro study evaluated the influence of luting agents on ultrasonic vibration time for intraradicular cast post removal. MATERIAL AND METHODS: After endodontic treatment, 30 roots of extracted human canines were embedded in resin cylinders. The post-holes were prepared at 10 mm depth and their impressions were taken using autopolymerizing acrylic resin. After casting procedures using a nickel-chromium alloy, the posts were randomly distributed into 3 groups (n=10 according to the luting material: G1- zinc phosphate (SS White (control group, G2 - glass ionomer cement (Vidrion C; SS White, and G3- resin cement (C&B; Bisco. In G3, the adhesive procedure was performed before post cementation. After 24 h, the cement line was removed at the post/tooth interface using a fine diamond bur, and the ST-09 tip of an Enac ultrasound unit was applied at maximum power on all surfaces surrounding the posts. The application time was recorded with a chronometer until the post was completely dislodged and data were analyzed by ANOVA and Tukey's test (p<0.05. RESULTS: The roots were removed from the acrylic resin and inspected to detect cracks and/or fractures. The means for G1, G2, and G3 were 168.5, 59.5, and 285 s, respectively, with statistically significant differences among them. Two G3 posts resisted removal, one of which developed a vertical fracture line. CONCLUSIONS: Therefore, the cement type had a direct influence on the time required for ultrasonic post removal. Compared to the zinc phosphate and glass ionomer cements, the resin cement required a longer ultrasonic vibration time.

  6. Multi-processor system for real-time flow estimation in medical ultrasound imaging

    DEFF Research Database (Denmark)

    Stetson, Paul F.; Jensen, Jesper Lomborg; Antonius, Peter

    1997-01-01

    the processed data. The generous bandwidth of the links makes it easy to balance the computational load among the processors.In order to manage the shared system memory and to make use of the parallel processing capabilities of the system, a real-time multitasking kernel has been developed. The kernel uses...

  7. Real-time non-rigid target tracking for ultrasound-guided clinical interventions

    NARCIS (Netherlands)

    Zachiu, Cornel; Ries, Mario G; Ramaekers, Pascal; Guey, Jean-Luc; Moonen, Chrit T W; de Senneville, Baudouin Denis

    2017-01-01

    Biological motion is a problem for non- or mini-invasive interventions when conducted in mobile/deformable organs due to the targeted pathology moving/deforming with the organ. This may lead to high miss rates and/or incomplete treatment of the pathology. Therefore, real-time tracking of the target

  8. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... use different transducers (with different capabilities) during a single exam. The transducer sends out high-frequency sound ... modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time ...

  9. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... organs and to examine a baby in pregnant women and the brain and hips in infants. It’s ... modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time ...

  10. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... be necessary. Your doctor will explain the exact reason why another exam is requested. Sometimes a follow- ... Ultrasound provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as ...

  11. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... and be made aware of food and drink restrictions that may be needed prior to sedation. Once ... modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time ...

  12. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... most ultrasound exams, you will be positioned lying face-up on an examination table that can be ... in a known abnormality can be monitored over time. Follow-up examinations are sometimes the best way ...

  13. Exposure Time Distributions reveal Denitrification Rates along Groundwater Flow Path of an Agricultural Unconfined Aquifer

    Science.gov (United States)

    Kolbe, T.; Abbott, B. W.; Thomas, Z.; Labasque, T.; Aquilina, L.; Laverman, A.; Babey, T.; Marçais, J.; Fleckenstein, J. H.; Peiffer, S.; De Dreuzy, J. R.; Pinay, G.

    2016-12-01

    Groundwater contamination by nitrate is nearly ubiquitous in agricultural regions. Nitrate is highly mobile in groundwater and though it can be denitrified in the aquifer (reduced to inert N2 gas), this process requires the simultaneous occurrence of anoxia, an electron donor (e.g. organic carbon, pyrite), nitrate, and microorganisms capable of denitrification. In addition to this the ratio of the time groundwater spent in a denitrifying environment (exposure time) to the characteristic denitrification reaction time plays an important role, because denitrification can only occur if the exposure time is longer than the characteristic reaction time. Despite a long history of field studies and numerical models, it remains exceedingly difficult to measure or model exposure times in the subsurface at the catchment scale. To approach this problem, we developed a unified modelling approach combining measured environmental proxies with an exposure time based reactive transport model. We measured groundwater age, nitrogen and sulfur isotopes, and water chemistry from agricultural wells in an unconfined aquifer in Brittany, France, to quantify changes in nitrate concentration due to dilution and denitrification. Field data showed large differences in nitrate concentrations among wells, associated with differences in the exposure time distributions. By constraining a catchment-scale characteristic reaction time for denitrification with water chemistry proxies and exposure times, we were able to assess rates of denitrification along groundwater flow paths. This unified modeling approach is transferable to other catchments and could be further used to investigate how catchment structure and flow dynamics interact with biogeochemical processes such as denitrification.

  14. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... do not use ionizing radiation (as used in x-rays ), thus there is no radiation exposure to the ... tissues that do not show up well on x-ray images. Ultrasound is the preferred imaging modality for ...

  15. Influence of different anoxic time exposures on active biomass, protozoa and filamentous bacteria in activated sludge.

    Science.gov (United States)

    Rodriguez-Perez, S; Fermoso, F G; Arnaiz, C

    Medium-sized wastewater treatment plants are considered too small to implement anaerobic digestion technologies and too large for extensive treatments. A promising option as a sewage sludge reduction method is the inclusion of anoxic time exposures. In the present study, three different anoxic time exposures of 12, 6 and 4 hours have been studied to reduce sewage sludge production. The best anoxic time exposure was observed under anoxic/oxic cycles of 6 hours, which reduced 29.63% of the biomass production compared with the oxic control conditions. The sludge under different anoxic time exposures, even with a lower active biomass concentration than the oxic control conditions, showed a much higher metabolic activity than the oxic control conditions. Microbiological results suggested that both protozoa density and abundance of filamentous bacteria decrease under anoxic time exposures compared to oxic control conditions. The anoxic time exposures 6/6 showed the highest reduction in both protozoa density, 37.5%, and abundance of filamentous bacteria, 41.1%, in comparison to the oxic control conditions. The groups of crawling ciliates, carnivorous ciliates and filamentous bacteria were highly influenced by the anoxic time exposures. Protozoa density and abundance of filamentous bacteria have been shown as promising bioindicators of biomass production reduction.

  16. [Comparison of two quantitative methods of endobronchial ultrasound real-time elastography for evaluating intrathoracic lymph nodes].

    Science.gov (United States)

    Mao, X W; Yang, J Y; Zheng, X X; Wang, L; Zhu, L; Li, Y; Xiong, H K; Sun, J Y

    2017-06-12

    Objective: To compare the clinical value of two quantitative methods in analyzing endobronchial ultrasound real-time elastography (EBUS-RTE) images for evaluating intrathoracic lymph nodes. Methods: From January 2014 to April 2014, EBUS-RTE examination was performed in patients who received EBUS-TBNA examination in Shanghai Chest Hospital. Each intrathoracic lymph node had a selected EBUS-RTE image. Stiff area ratio and mean hue value of region of interest (ROI) in each image were calculated respectively. The final diagnosis of lymph node was based on the pathologic/microbiologic results of EBUS-TBNA, pathologic/microbiologic results of other examinations and clinical following-up. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy were evaluated for distinguishing malignant and benign lesions. Results: Fifty-six patients and 68 lymph nodes were enrolled in this study, of which 35 lymph nodes were malignant and 33 lymph nodes were benign. The stiff area ratio and mean hue value of benign and malignant lesions were 0.32±0.29, 0.62±0.20 and 109.99±28.13, 141.62±17.52, respectively, and statistical differences were found in both of those two methods ( t =-5.14, P methods can be used for analyzing EBUS-RTE images quantitatively, having the value of differentiating benign and malignant intrathoracic lymph nodes, and the stiff area ratio is better than the mean hue value between the two methods.

  17. The design of a miniature personal exposure monitor for continuous real-time data acquisition in electromagnetic field exposure assessment

    International Nuclear Information System (INIS)

    Hansen, N.H.; Conroy, T.J.; Wilson, B.W.

    1994-06-01

    The design of a small, light-weight personal exposure monitor suitable for use in EMF exposure assessment studies is nearing completion at Pacific Northwest Laboratory. The monitor is designed to be non-obtrusive, battery operated, and able to continuously record extremely low-frequency (ELF) (1Ohz--500hz) magnetic-field data. It also captures high-frequency (500hz--1OMhz) transients that exceed a preset threshold, retaining the largest transients in memory. The monitor can record one or more days of data on a single easily replaceable, credit-card-size memory (PCMCIA). A battery charge will last a minimum of one day. Batteries are rechargeable and easily replaced. A data-compression algorithm is under development that will be tailored to the efficient compression of low-frequency EMF signals and will permit data to be logged for at least one day before swapping memory cards. The memory cards are readable by a base- station computer that can perform analysis of the data. The monitor is designed to accommodate four inputs supporting full-field sensors as well as a proposed ocular exposure measurement system. Our design effort has shown that a practical personal exposure monitor for EMF can be built based on current technology, continuous logging of real-time ELF waveforms is both feasible and practical, and such a device is appropriate for proposed EMF exposure studies

  18. Radiation exposure during ESWL

    International Nuclear Information System (INIS)

    McCullough, D.L.; Van Swearingen, F.L.; Dyer, R.B.; Appel, B.

    1987-01-01

    This paper discusses exposure to ionizing radiation by the ESWL patient and for health professionals. Although the patient is exposed acutely to the highest level of radiation, the lithotripter team is chronically exposed to ionizing radiation at varying levels. Attention to detail is important in reducing that exposure. The operator should follow the guidelines set forth in this chapter in order to minimize exposure to the patient, himself or herself, and to all co-workers. At the present time, investigation of an alternative modality for stone localization, ultrasound, is being investigated

  19. Micromachined silicon parallel acoustic delay lines as time-delayed ultrasound detector array for real-time photoacoustic tomography

    Science.gov (United States)

    Cho, Y.; Chang, C.-C.; Wang, L. V.; Zou, J.

    2016-02-01

    This paper reports the development of a new 16-channel parallel acoustic delay line (PADL) array for real-time photoacoustic tomography (PAT). The PADLs were directly fabricated from single-crystalline silicon substrates using deep reactive ion etching. Compared with other acoustic delay lines (e.g., optical fibers), the micromachined silicon PADLs offer higher acoustic transmission efficiency, smaller form factor, easier assembly, and mass production capability. To demonstrate its real-time photoacoustic imaging capability, the silicon PADL array was interfaced with one single-element ultrasonic transducer followed by one channel of data acquisition electronics to receive 16 channels of photoacoustic signals simultaneously. A PAT image of an optically-absorbing target embedded in an optically-scattering phantom was reconstructed, which matched well with the actual size of the imaged target. Because the silicon PADL array allows a signal-to-channel reduction ratio of 16:1, it could significantly simplify the design and construction of ultrasonic receivers for real-time PAT.

  20. Micromachined silicon parallel acoustic delay lines as time-delayed ultrasound detector array for real-time photoacoustic tomography

    International Nuclear Information System (INIS)

    Cho, Y; Chang, C-C; Zou, J; Wang, L V

    2016-01-01

    This paper reports the development of a new 16-channel parallel acoustic delay line (PADL) array for real-time photoacoustic tomography (PAT). The PADLs were directly fabricated from single-crystalline silicon substrates using deep reactive ion etching. Compared with other acoustic delay lines (e.g., optical fibers), the micromachined silicon PADLs offer higher acoustic transmission efficiency, smaller form factor, easier assembly, and mass production capability. To demonstrate its real-time photoacoustic imaging capability, the silicon PADL array was interfaced with one single-element ultrasonic transducer followed by one channel of data acquisition electronics to receive 16 channels of photoacoustic signals simultaneously. A PAT image of an optically-absorbing target embedded in an optically-scattering phantom was reconstructed, which matched well with the actual size of the imaged target. Because the silicon PADL array allows a signal-to-channel reduction ratio of 16:1, it could significantly simplify the design and construction of ultrasonic receivers for real-time PAT. (paper)

  1. interactive effect of cowpea variety, dose and exposure time

    African Journals Online (AJOL)

    ACSS

    Callosobruchus maculatus has for years remained a serious menace in cowpea in Sub-Sahara Africa. The objective of this study was to investigate the effect of genotypic cowpea (Vigna unguiculata (L.) Walp) varieties, time and dose on C. maculatus exposed to powders of Piper guineense and Eugenia aromatica.

  2. Evaluation of human muscle hardness after dynamic exercise with ultrasound real-time tissue elastography: A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Yanagisawa, O., E-mail: o.yanagisawa@aoni.waseda.jp [Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama (Japan); Niitsu, M. [Department of Radiological Science, Faculty of Health Sciences, Tokyo Metropolitan University, Arakawa-ku, Tokyo (Japan); Kurihara, T. [Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga (Japan); Fukubayashi, T. [Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama (Japan)

    2011-09-15

    Aim: To assess the feasibility of ultrasound real-time tissue elastography (RTE) for measuring exercise-induced changes in muscle hardness and to compare the findings of RTE with those of a tissue hardness meter for semi-quantitative assessment of the hardness of exercised muscles. Materials and methods: Nine male participants performed an arm-curl exercise. RTE measurements were performed by manually applying repetitive compression with the transducer on the scan position before exercise, immediately after exercise, and at 30 min after exercise; strain ratios between muscle and a reference material (hydrogel) were calculated (muscle strain/material strain). A tissue hardness meter was also used to evaluate muscle hardness. The intraclass correlation coefficients (ICCs) for the three repeated measurements at each measurement time were calculated to evaluate the intra-observer reproducibility of each technique. Results: Immediately after exercise, the strain ratio and the value obtained using the tissue hardness meter significantly decreased (from 1.65 to 1.35) and increased (from 51.8 to 54.3), respectively. Both parameters returned to their pre-exercise value 30 min after exercise. The ICCs of the RTE (and the ICCs of the muscle hardness meter) were 0.971 (0.816) before exercise, 0.939 (0.776) immediately after exercise, and 0.959 (0.882) at 30 min after exercise. Conclusion: Similar to the muscle hardness meter, RTE revealed the exercise-induced changes of muscle hardness semi-quantitatively. The intra-observer reproducibility of RTE was very high at each measurement time. These findings suggest that RTE is a clinically useful technique for assessing hardness of specific exercised muscles.

  3. Evaluation of human muscle hardness after dynamic exercise with ultrasound real-time tissue elastography: A feasibility study

    International Nuclear Information System (INIS)

    Yanagisawa, O.; Niitsu, M.; Kurihara, T.; Fukubayashi, T.

    2011-01-01

    Aim: To assess the feasibility of ultrasound real-time tissue elastography (RTE) for measuring exercise-induced changes in muscle hardness and to compare the findings of RTE with those of a tissue hardness meter for semi-quantitative assessment of the hardness of exercised muscles. Materials and methods: Nine male participants performed an arm-curl exercise. RTE measurements were performed by manually applying repetitive compression with the transducer on the scan position before exercise, immediately after exercise, and at 30 min after exercise; strain ratios between muscle and a reference material (hydrogel) were calculated (muscle strain/material strain). A tissue hardness meter was also used to evaluate muscle hardness. The intraclass correlation coefficients (ICCs) for the three repeated measurements at each measurement time were calculated to evaluate the intra-observer reproducibility of each technique. Results: Immediately after exercise, the strain ratio and the value obtained using the tissue hardness meter significantly decreased (from 1.65 to 1.35) and increased (from 51.8 to 54.3), respectively. Both parameters returned to their pre-exercise value 30 min after exercise. The ICCs of the RTE (and the ICCs of the muscle hardness meter) were 0.971 (0.816) before exercise, 0.939 (0.776) immediately after exercise, and 0.959 (0.882) at 30 min after exercise. Conclusion: Similar to the muscle hardness meter, RTE revealed the exercise-induced changes of muscle hardness semi-quantitatively. The intra-observer reproducibility of RTE was very high at each measurement time. These findings suggest that RTE is a clinically useful technique for assessing hardness of specific exercised muscles.

  4. Population exposure to ultraviolet radiation in Finland 1920-1995: Exposure trends and a time-series analysis of exposure and cutaneous melanoma incidence

    International Nuclear Information System (INIS)

    Kojo, Katja; Jansen, Christer T.; Nybom, Pia; Huurto, Laura; Laihia, Jarmo; Ilus, Taina; Auvinen, Anssi

    2006-01-01

    Ultraviolet radiation (UVR) is the principal cause of cutaneous malignant melanoma (CMM). However, the relation between CMM and UVR exposure is not clear. We present the trends of population exposure to UVR and conduct a time-series analysis of the relation between UVR exposure and incidence of CMM. Data on CMM incidence were obtained from the Finnish Cancer Registry. Clothing coverage of the body was scored from archival photographs and the proportion of uncovered skin was used as a measure of solar exposure. Information on the number of sunny resort holidays, duration of annual holidays, and sunscreen sales were obtained from various sources. Exposed skin area doubled from 1920 to 1985. The average duration of annual holidays increased 30-fold. The number of sunny resort holidays and the sales of sunscreens increased rapidly from 1980. CMM was most strongly associated with solar exposure of 5-19 years earlier. There is a considerable decrease in clothing coverage during the 20th century. UVR exposure preceding CMM occurrence 4 years or less does not appear relevant, whereas the period 5-19 years prior to CMM occurrence might be the most relevant period. However, findings of ecological studies may not be applicable at the individual level

  5. Odors: appetizing or satiating? Development of appetite during odor exposure over time

    NARCIS (Netherlands)

    Ramaekers, M.G.; Boesveldt, S.; Lakemond, C.M.M.; Boekel, van M.A.J.S.; Luning, P.A.

    2014-01-01

    Background: Exposure to palatable food odors influences appetite responses, either promoting or inhibiting food intake. Possibly, food odors are appetizing after a short exposure (of circa 1–3¿min), but become satiating over time (circa 10–20¿min). Objective: To investigate the effect of odor

  6. Time characteristics of distortion product otoacoustic emissions recovery function after moderate sound exposure

    DEFF Research Database (Denmark)

    de Toro, Miguel Angel Aranda; Ordoñez, Rodrigo Pizarro; Hammershøi, Dorte

    2006-01-01

    Exposure to sound of moderate level temporarily attenuates the amplitude of distortion product otoacoustic emissions (DPOAEs). These changes are similar to the changes observed in absolute hearing thresholds after similar sound exposures. To be able to assess changes over time across a broad...

  7. Real-time co-registered ultrasound and photoacoustic imaging system based on FPGA and DSP architecture

    Science.gov (United States)

    Alqasemi, Umar; Li, Hai; Aguirre, Andres; Zhu, Quing

    2011-03-01

    Co-registering ultrasound (US) and photoacoustic (PA) imaging is a logical extension to conventional ultrasound because both modalities provide complementary information of tumor morphology, tumor vasculature and hypoxia for cancer detection and characterization. In addition, both modalities are capable of providing real-time images for clinical applications. In this paper, a Field Programmable Gate Array (FPGA) and Digital Signal Processor (DSP) module-based real-time US/PA imaging system is presented. The system provides real-time US/PA data acquisition and image display for up to 5 fps* using the currently implemented DSP board. It can be upgraded to 15 fps, which is the maximum pulse repetition rate of the used laser, by implementing an advanced DSP module. Additionally, the photoacoustic RF data for each frame is saved for further off-line processing. The system frontend consists of eight 16-channel modules made of commercial and customized circuits. Each 16-channel module consists of two commercial 8-channel receiving circuitry boards and one FPGA board from Analog Devices. Each receiving board contains an IC† that combines. 8-channel low-noise amplifiers, variable-gain amplifiers, anti-aliasing filters, and ADC's‡ in a single chip with sampling frequency of 40MHz. The FPGA board captures the LVDSξ Double Data Rate (DDR) digital output of the receiving board and performs data conditioning and subbeamforming. A customized 16-channel transmission circuitry is connected to the two receiving boards for US pulseecho (PE) mode data acquisition. A DSP module uses External Memory Interface (EMIF) to interface with the eight 16-channel modules through a customized adaptor board. The DSP transfers either sub-beamformed data (US pulse-echo mode or PAI imaging mode) or raw data from FPGA boards to its DDR-2 memory through the EMIF link, then it performs additional processing, after that, it transfer the data to the PC** for further image processing. The PC code

  8. Real-time contrast ultrasound muscle perfusion imaging with intermediate-power imaging coupled with acoustically durable microbubbles.

    Science.gov (United States)

    Seol, Sang-Hoon; Davidson, Brian P; Belcik, J Todd; Mott, Brian H; Goodman, Reid M; Ammi, Azzdine; Lindner, Jonathan R

    2015-06-01

    There is growing interest in limb contrast-enhanced ultrasound (CEU) perfusion imaging for the evaluation of peripheral artery disease. Because of low resting microvascular blood flow in skeletal muscle, signal enhancement during limb CEU is prohibitively low for real-time imaging. The aim of this study was to test the hypothesis that this obstacle can be overcome by intermediate- rather than low-power CEU when performed with an acoustically resilient microbubble agent. Viscoelastic properties of Definity and Sonazoid were assessed by measuring bulk modulus during incremental increases in ambient pressure to 200 mm Hg. Comparison of in vivo microbubble destruction and signal enhancement at a mechanical index (MI) of 0.1 to 0.4 was performed by sequential reduction in pulsing interval from 10 to 0.05 sec during limb CEU at 7 MHz in mice and 1.8 MHz in dogs. Destruction was also assessed by broadband signal generation during passive cavitation detection. Real-time CEU perfusion imaging with destruction-replenishment was then performed at 1.8 MHz in dogs using an MI of 0.1, 0.2, or 0.3. Sonazoid had a higher bulk modulus than Definity (66 ± 12 vs 29 ± 2 kPa, P = .02) and exhibited less inertial cavitation (destruction) at MIs ≥ 0.2. On in vivo CEU, maximal signal intensity increased incrementally with MI for both agents and was equivalent between agents except at an MI of 0.1 (60% and 85% lower for Sonazoid at 7 and 1.8 MHz, respectively, P power imaging coupled with a durable microbubble contrast agent. Copyright © 2015 American Society of Echocardiography. All rights reserved.

  9. Dual-mode photoacoustic and ultrasound system for real-time in-vivo ovarian cancer imaging

    Science.gov (United States)

    Mostafa, Atahar; Nandy, Sreyankar; Amidi, Eghbal; Zhu, Quing

    2018-02-01

    More than 80% of the ovarian cancers are diagnosed at late stages and the survival rate is less than 50%. Currently, there is no effective screening technique available and transvaginal US can only tell if the ovaries are enlarged or not. We have developed a new real-time co-registered US and photoacoustic system for in vivo imaging and characterization of ovaries. US is used to localize ovaries and photoacoustic imaging provides functional information about ovarian tissue angiogenesis and oxygenation saturation. The system consists of a tunable laser and a commercial US system from Alpinion Inc. The Alpinion system is cable of providing channel data for both US pulse-echo and photoacoustic imaging and can be programmed as a computer terminal for display US and photoacoustic images side by side or in coregistered mode. A transvaginal ultrasound probe of 6-MHz center frequency and bandwidth of 3-10 MHz is coupled with four optical fibers surrounded the US probe to deliver the light to tissue. The light from optical fibers is homogenized to ensure the power delivered to the tissue surface is below the FDA required limit. Physicians can easily navigate the probe and use US to look for ovaries and then turn on photoacoustic mode to provide real-time tumor vasculature and So2 saturation maps. With the optimized system, we have successfully imaged first group of 7 patients of malignant, abnormal and benign ovaries. The results have shown that both photoacoustic signal strength and spatial distribution are different between malignant and abnormal and benign ovaries.

  10. Remote tele-mentored ultrasound for non-physician learners using FaceTime: A feasibility study in a low-income country.

    Science.gov (United States)

    Robertson, Thomas E; Levine, Andrea R; Verceles, Avelino C; Buchner, Jessica A; Lantry, James H; Papali, Alfred; Zubrow, Marc T; Colas, L Nathalie; Augustin, Marc E; McCurdy, Michael T

    2017-08-01

    Ultrasound (US) is a burgeoning diagnostic tool and is often the only available imaging modality in low- and middle-income countries (LMICs). However, bedside providers often lack training to acquire or interpret US images. We conducted a study to determine if a remote tele-intensivist could mentor geographically removed LMIC providers to obtain quality and clinically useful US images. Nine Haitian non-physician health care workers received a 20-minute training on basic US techniques. A volunteer was connected to an intensivist located in the USA via FaceTime. The intensivist remotely instructed the non-physicians to ultrasound five anatomic sites. The tele-intensivist evaluated the image quality and clinical utility of performing tele-ultrasound in a LMIC. The intensivist agreed (defined as "agree" or "strongly agree" on a five-point Likert scale) that 90% (57/63) of the FaceTime images were high quality. The intensivist felt comfortable making clinical decisions using FaceTime images 89% (56/63) of the time. Non-physicians can feasibly obtain high-quality and clinically relevant US images using video chat software in LMICs. Commercially available software can connect providers in institutions in LMICs to geographically removed intensivists at a relatively low cost and without the need for extensive training of local providers. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Novel real-time feedback and integrated simulation model for teaching and evaluating ultrasound-guided regional anesthesia skills in pediatric anesthesia trainees.

    Science.gov (United States)

    Moore, David L; Ding, Lili; Sadhasivam, Senthilkumar

    2012-09-01

    To assess, teach, and improve core competencies and skills sets associated with ultrasound-guided regional anesthesia (UGRA) of pediatric anesthesia trainees. To effectively assess and improve UGRA-associated cognitive and technical skills and proficiency of pediatric anesthesia trainees using simulators and real-time feedback. Ultrasound usage has been increasingly adopted by anesthesiologists to perform regional anesthesia. Pediatric UGRA performance significantly lags behind adult UGRA practice. Lack of effective UGRA training is the major reason for this unfortunate lag. Integration of ultrasound imaging, target location, and needling skills are crucial in safely performing UGRA. However, there are no standards to ensure proficiency in practice, nor in training. We implemented an UGRA instructional program for all trainees, in two parts. First, we used a unique training model for initial assessment and training of technical skills. Second, we used an instructional program that encompasses UGRA and equipment-associated cognitive skills. After baseline assessment at 0 months, we retested these trainees at 6 and 12 months to identify progression of proficiency over time. Cognitive and technical UGRA skills of trainees improved significantly over the course of time. UGRA performance average accuracy improved to 79% at 12 months from the baseline accuracy of 57%. Cognitive UGRA-related skills of trainees improved from baseline results of 52.5-79.2% at 12 months. Implementing a multifaceted assessment and real-time feedback-based training has significantly improved UGRA-related cognitive and technical skills and proficiency of pediatric anesthesia trainees. © 2012 Blackwell Publishing Ltd.

  12. How to statistically analyze nano exposure measurement results: using an ARIMA time series approach

    International Nuclear Information System (INIS)

    Klein Entink, Rinke H.; Fransman, Wouter; Brouwer, Derk H.

    2011-01-01

    Measurement strategies for exposure to nano-sized particles differ from traditional integrated sampling methods for exposure assessment by the use of real-time instruments. The resulting measurement series is a time series, where typically the sequential measurements are not independent from each other but show a pattern of autocorrelation. This article addresses the statistical difficulties when analyzing real-time measurements for exposure assessment to manufactured nano objects. To account for autocorrelation patterns, Autoregressive Integrated Moving Average (ARIMA) models are proposed. A simulation study shows the pitfalls of using a standard t-test and the application of ARIMA models is illustrated with three real-data examples. Some practical suggestions for the data analysis of real-time exposure measurements conclude this article.

  13. Left truncation results in substantial bias of the relation between time-dependent exposures and adverse events

    NARCIS (Netherlands)

    Hazelbag, Christijan M; Klungel, Olaf H; van Staa, Tjeerd P; de Boer, Anthonius; Groenwold, Rolf H H

    PURPOSE: To assess the impact of random left truncation of data on the estimation of time-dependent exposure effects. METHODS: A simulation study was conducted in which the relation between exposure and outcome was based on an immediate exposure effect, a first-time exposure effect, or a cumulative

  14. Left truncation results in substantial bias of the relation between time-dependent exposures and adverse events

    NARCIS (Netherlands)

    Hazelbag, Christijan M.; Klungel, Olaf H.; van Staa, Tjeerd P.; de Boer, Anthonius; Groenwold, Rolf H H

    2015-01-01

    PURPOSE: To assess the impact of random left truncation of data on the estimation of time-dependent exposure effects. METHODS: A simulation study was conducted in which the relation between exposure and outcome was based on an immediate exposure effect, a first-time exposure effect, or a cumulative

  15. Behavioral Changes Over Time Following Ayahuasca Exposure in Zebrafish.

    Science.gov (United States)

    Savoldi, Robson; Polari, Daniel; Pinheiro-da-Silva, Jaquelinne; Silva, Priscila F; Lobao-Soares, Bruno; Yonamine, Mauricio; Freire, Fulvio A M; Luchiari, Ana C

    2017-01-01

    The combined infusion of Banisteriopsis caapi stem and Psychotria viridis leaves, known as ayahuasca, has been used for centuries by indigenous tribes. The infusion is rich in N , N -dimethyltryptamine (DMT) and monoamine oxidase inhibitors, with properties similar to those of serotonin. Despite substantial progress in the development of new drugs to treat anxiety and depression, current treatments have several limitations. Alternative drugs, such as ayahuasca, may shed light on these disorders. Here, we present time-course behavioral changes induced by ayahuasca in zebrafish, as first step toward establishing an ideal concentration for pre-clinical evaluations. We exposed adult zebrafish to five concentrations of the ayahuasca infusion: 0 (control), 0.1, 0.5, 1, and 3 ml/L ( n = 14 each group), and behavior was recorded for 60 min. We evaluated swimming speed, distance traveled, freezing and bottom dwelling every min for 60 min. Swimming speed and distance traveled decreased with an increase in ayahuasca concentration while freezing increased with 1 and 3 ml/L. Bottom dwelling increased with 1 and 3 ml/L, but declined with 0.1 ml/L. Our data suggest that small amounts of ayahuasca do not affect locomotion and reduce anxiety-like behavior in zebrafish, while increased doses of the drug lead to crescent anxiogenic effects. We conclude that the temporal analysis of zebrafish behavior is a sensitive method for the study of ayahuasca-induced functional changes in the vertebrate brain.

  16. Behavioral Changes Over Time Following Ayahuasca Exposure in Zebrafish

    Directory of Open Access Journals (Sweden)

    Robson Savoldi

    2017-07-01

    Full Text Available The combined infusion of Banisteriopsis caapi stem and Psychotria viridis leaves, known as ayahuasca, has been used for centuries by indigenous tribes. The infusion is rich in N, N-dimethyltryptamine (DMT and monoamine oxidase inhibitors, with properties similar to those of serotonin. Despite substantial progress in the development of new drugs to treat anxiety and depression, current treatments have several limitations. Alternative drugs, such as ayahuasca, may shed light on these disorders. Here, we present time-course behavioral changes induced by ayahuasca in zebrafish, as first step toward establishing an ideal concentration for pre-clinical evaluations. We exposed adult zebrafish to five concentrations of the ayahuasca infusion: 0 (control, 0.1, 0.5, 1, and 3 ml/L (n = 14 each group, and behavior was recorded for 60 min. We evaluated swimming speed, distance traveled, freezing and bottom dwelling every min for 60 min. Swimming speed and distance traveled decreased with an increase in ayahuasca concentration while freezing increased with 1 and 3 ml/L. Bottom dwelling increased with 1 and 3 ml/L, but declined with 0.1 ml/L. Our data suggest that small amounts of ayahuasca do not affect locomotion and reduce anxiety-like behavior in zebrafish, while increased doses of the drug lead to crescent anxiogenic effects. We conclude that the temporal analysis of zebrafish behavior is a sensitive method for the study of ayahuasca-induced functional changes in the vertebrate brain.

  17. Variations with time and age in the relative risks of solid cancer incidence after radiation exposure

    International Nuclear Information System (INIS)

    Little, M.P.; Muirhead, C.R.; de Vathaire, F.; Charles, M.W.

    1997-01-01

    The Japanese atomic bomb survivor cancer incidence dataset and data on five groups exposed to radiation for medical reasons in childhood are analysed and evidence found for a reduction in the radiation-induced relative risk of cancers other than leukaemia with increasing time since exposure and age at exposure. The rate of the reductions in relative risk with time since exposure are not significantly different for those exposed in childhood and for those exposed in adulthood, if adjustment is made for the effects on the relative risk of age at exposure. For those irradiated in childhood, there is a statistically significant annual reduction of 5.8% (95% Cl 2.8, 8.9) in excess relative risk, and there are no strong indications of inter-cohort heterogeniety in the speed of reduction of relative risk. After adjustment for the effects of age at exposure, there is a significant annual reduction of 3.6% (95% Cl 1.6, 5.6) in excess relative risk in all age-at-exposure groups. There are significant reductions of 5.2% (95% Cl 3.7, 6.8) in excess relative risk per year of age at exposure. There are statistically significant (P = 0.04) interactions between the exponential adjustments to the excess relative risk for age at exposure and time since exposure in the Japanese data, but no indications (P = 0.38) of such interactions when powers of time since exposure and attained age are used to adjust the excess relative risk, so that the fit of the model with power adjustments is to be preferred to that of the model with exponential adjustments. (author)

  18. Child and adolescent exposure to food and beverage brand appearances during prime-time television programming.

    Science.gov (United States)

    Speers, Sarah E; Harris, Jennifer L; Schwartz, Marlene B

    2011-09-01

    The food industry disproportionately markets to young people through product placements. Children and adolescents may be more susceptible to these disguised persuasive attempts. Quantify incidence and youth exposure to food and beverage brand appearances within shows on prime-time TV. Data on the number of food, beverage, and restaurant brand appearances within shows during prime-time programming in 2008 were purchased from Nielsen and analyzed by product category and company in 2010. Exposure to these brand appearances by children, adolescents, and adults were examined and compared with exposure to prime-time TV advertisements for the same categories and companies using additional Nielsen data. Food, beverage, and restaurant brands appeared a total of 35,000 times within prime-time TV programming examined by Nielsen in 2008. Regular soft drinks, traditional restaurants (i.e., not quickserve), and energy/sports drinks made up 60% of all brand appearances. Young people viewed relatively few of these appearances with one notable exception. Coca-Cola products were seen 198 times by the average child and 269 times by the average adolescent during prime-time shows over the year, accounting for 70% of child exposure and 61% of adolescent exposure to brand appearances. One show, American Idol, accounted for more than 95% of these exposures. Exposure of children to Coca-Cola products through traditional advertisements was much less common. Brand appearances for most food industry companies, except for Coca-Cola, are relatively rare during prime-time programming with large youth audiences. Coca-Cola has pledged to refrain from advertising to children, yet the average child views almost four Coke appearances on prime-time TV every week. This analysis reveals a substantial, potential loophole in current food industry self-regulatory pledges to advertise only better-for-you foods to children. Copyright © 2011 American Journal of Preventive Medicine. Published by Elsevier Inc

  19. Impact of Indocyanine Green Concentration, Exposure Time, and Degree of Dissolution in Creating Toxic Anterior Segment Syndrome: Evaluation in a Rabbit Model

    Directory of Open Access Journals (Sweden)

    Tamer Tandogan

    2016-01-01

    Full Text Available Purpose. To investigate the role of indocyanine green (ICG dye as a causative material of toxic anterior segment syndrome (TASS in an experimental rabbit model. Method. Eight eyes of four rabbits were allocated to this study. Capsular staining was performed using ICG dye, after which the anterior chamber was irrigated with a balanced salt solution. The effects of different concentrations (control, 0.25, 0.5, and 1.0%, exposure times (10 and 60 seconds, and the degree of dissolution (differently vortexed were investigated. The analysis involved anterior segment photography, ultrasound pachymetry, prostaglandin assay (PGE2 Parameter Assay, R&D systems, Inc., and scanning electron microscopy of each iris. Result. There was no reaction in the control eye. A higher aqueous level of PGE2 and more severe inflammatory reaction were observed in cases of eyes with higher concentration, longer exposure time, and poorly dissolved dye. Additionally, scanning electron microscopy revealed larger and coarser ICG particles. Conclusion. TASS occurrence may be associated with the concentration, exposure time, and degree of dissolution of ICG dye during cataract surgery.

  20. Assessment of the vaginal residence time of biomarkers of semen exposure.

    Science.gov (United States)

    Thurman, Andrea; Jacot, Terry; Melendez, Johan; Kimble, Thomas; Snead, Margaret; Jamshidi, Roxanne; Wheeless, Angie; Archer, David F; Doncel, Gustavo F; Mauck, Christine

    2016-11-01

    The primary objective of this pilot study is to determine and compare the residence time in the vagina of biomarkers of semen exposure for up to 15 days post exposure. The biomarkers are prostate-specific antigen (PSA), Y chromosome DNA, the sex determining region of the Y chromosome (SRY) and testis-specific protein Y-encoded 4 (TSPY4). The secondary objectives are to determine if biomarker concentrations differed between intercourse and inoculation groups, to establish whether the sampling frequency post exposure affected biomarker concentrations and decay profile and to determine if biomarker concentrations in vaginal swabs obtained by the participant at home were similar to swabs obtained by the nurse in the clinic. We randomized healthy women to unprotected intercourse (n=17) versus vaginal inoculation with the male partner's semen in the clinic (n=16). Women were then further randomized to have vaginal swabs obtained at either 7 or 4 time points after semen exposure, up to 15 days post exposure, either obtained at home by the participant or in the clinic by the research nurse. PSA and SRY were markers of recent semen exposure. TSPY4 was detectable in approximately 50% of participants at 15 days post exposure. Unprotected intercourse resulted in significantly higher concentrations of select biomarkers. Sampling frequency and home versus clinic sampling had no significant effect on biomarker concentrations. Objective biomarkers of recent or distant semen exposure may have great utility for verifying protocol compliance in a variety of clinical trials. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Passive cavitation imaging with ultrasound arrays.

    Science.gov (United States)

    Salgaonkar, Vasant A; Datta, Saurabh; Holland, Christy K; Mast, T Douglas

    2009-12-01

    A method is presented for passive imaging of cavitational acoustic emissions using an ultrasound array, with potential application in real-time monitoring of ultrasound ablation. To create such images, microbubble emissions were passively sensed by an imaging array and dynamically focused at multiple depths. In this paper, an analytic expression for a passive image is obtained by solving the Rayleigh-Sommerfield integral, under the Fresnel approximation, and passive images were simulated. A 192-element array was used to create passive images, in real time, from 520-kHz ultrasound scattered by a 1-mm steel wire. Azimuthal positions of this target were accurately estimated from the passive images. Next, stable and inertial cavitation was passively imaged in saline solution sonicated at 520 kHz. Bubble clusters formed in the saline samples were consistently located on both passive images and B-scans. Passive images were also created using broadband emissions from bovine liver sonicated at 2.2 MHz. Agreement was found between the images and source beam shape, indicating an ability to map therapeutic ultrasound beams in situ. The relation between these broadband emissions, sonication amplitude, and exposure conditions are discussed.

  2. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... internal organs, as well as blood flowing through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. ...

  3. Association of Light Exposure on Physical Activity and Sedentary Time in Young People

    Directory of Open Access Journals (Sweden)

    Daniel Aggio

    2015-03-01

    Full Text Available Background: To investigate whether light exposure was associated with objectively measured physical activity (PA and sedentary behaviour in young people. Methods: Participants (n = 229, 46.7% female were young people (mean 8.8 years [SD ± 2.2] from the borough of Camden, UK. Daily sedentary time, moderate and vigorous PA (MVPA and light exposure were measured using a tri-axial accelerometer with an ambient light sensor during the summer. Multiple linear regression models examined associations between average daily light exposure, sedentary time and time in MVPA. Models were repeated investigating weekdays and weekend days separately. Analyses were adjusted for pre-specified covariables, including age, sex, device wear time, ethnic group, school and body fat. Results: There were significant associations between average daily light exposure and time sedentary (β coefficient = −11.2, 95% CI, −19.0 to −3.4 and in MVPA (β coefficient = 3.5, 95% CI, 1.2 to 5.9. Light exposure was significantly associated with weekend sedentary time (β coefficient = −10.0, 95% CI, −17.6, −2.4, weekend MVPA (β coefficient = 3.7, 95% CI, 1.7, 5.7, weekday sedentary time (β coefficient = −15.0, 95% CI, −22.7 to −7.2, but not weekday MVPA (β coefficient = 2.0, 95% CI, −0.5 to 4.5. Conclusion: Average daily light exposure is positively associated with time in MVPA and negatively associated with sedentary time. Increasing daylight exposure may be a useful intervention strategy for promoting physical activity.

  4. Bedtime and evening light exposure influence circadian timing in preschool-age children: A field study

    Directory of Open Access Journals (Sweden)

    Lameese D. Akacem

    2016-11-01

    Full Text Available Light exposure and sleep timing are two factors that influence inter-individual variability in the timing of the human circadian clock. The aim of this study was to quantify the degree to which evening light exposure predicts variance in circadian timing over and above bedtime alone in preschool children. Participants were 21 children ages 4.5–5.0 years (4.7±0.2 years; 9 females. Children followed their typical sleep schedules for 4 days during which time they wore a wrist actigraph to assess sleep timing and a pendant light meter to measure minute-by-minute illuminance levels in lux. On the 5th day, children participated in an in-home dim-light melatonin onset (DLMO assessment. Light exposure in the 2 h before bedtime was averaged and aggregated across the 4 nights preceding the DLMO assessment. Mean DLMO and bedtime were 19:22±01:04 and 20:07±00:46, respectively. Average evening light exposure was 710.1±1418.2 lux. Children with later bedtimes (lights-off time had more delayed melatonin onset times (r=0.61, p=0.002. Evening light exposure was not independently associated with DLMO (r=0.32, p=0.08; however, a partial correlation between evening light exposure and DLMO when controlling for bedtime yielded a positive correlation (r=0.46, p=0.02. Bedtime explained 37.3% of the variance in the timing of DLMO, and evening light exposure accounted for an additional 13.3% of the variance. These findings represent an important step in understanding factors that influence circadian phase in preschool-age children and have implications for understanding a modifiable pathway that may underlie late sleep timing and the development of evening settling problems in early childhood.

  5. TH-AB-202-05: BEST IN PHYSICS (JOINT IMAGING-THERAPY): First Online Ultrasound-Guided MLC Tracking for Real-Time Motion Compensation in Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Ipsen, S; Bruder, R; Schweikard, A [University of Luebeck, Luebeck, DE (United States); O’Brien, R; Keall, P [University of Sydney, Sydney (Australia); Poulsen, P [Aarhus University Hospital, Aarhus (Denmark)

    2016-06-15

    Purpose: While MLC tracking has been successfully used for motion compensation of moving targets, current real-time target localization methods rely on correlation models with x-ray imaging or implanted electromagnetic transponders rather than direct target visualization. In contrast, ultrasound imaging yields volumetric data in real-time (4D) without ionizing radiation. We report the first results of online 4D ultrasound-guided MLC tracking in a phantom. Methods: A real-time tracking framework was installed on a 4D ultrasound station (Vivid7 dimension, GE) and used to detect a 2mm spherical lead marker inside a water tank. The volumetric frame rate was 21.3Hz (47ms). The marker was rigidly attached to a motion stage programmed to reproduce nine tumor trajectories (five prostate, four lung). The 3D marker position from ultrasound was used for real-time MLC aperture adaption. The tracking system latency was measured and compensated by prediction for lung trajectories. To measure geometric accuracy, anterior and lateral conformal fields with 10cm circular aperture were delivered for each trajectory. The tracking error was measured as the difference between marker position and MLC aperture in continuous portal imaging. For dosimetric evaluation, 358° VMAT fields were delivered to a biplanar diode array dosimeter using the same trajectories. Dose measurements with and without MLC tracking were compared to a static reference dose using a 3%/3 mm γ-test. Results: The tracking system latency was 170ms. The mean root-mean-square tracking error was 1.01mm (0.75mm prostate, 1.33mm lung). Tracking reduced the mean γ-failure rate from 13.9% to 4.6% for prostate and from 21.8% to 0.6% for lung with high-modulation VMAT plans and from 5% (prostate) and 18% (lung) to 0% with low modulation. Conclusion: Real-time ultrasound tracking was successfully integrated with MLC tracking for the first time and showed similar accuracy and latency as other methods while holding the

  6. Ultrasound treatment on phenolic metabolism and antioxidant capacity of fresh-cut pineapple during cold storage.

    Science.gov (United States)

    Yeoh, Wei Keat; Ali, Asgar

    2017-02-01

    Ultrasound treatment at different power output (0, 25 and 29W) and exposure time (10 and 15min) was used to investigate its effect on the phenolic metabolism enzymes, total phenolic content and antioxidant capacity of fresh-cut pineapple. Following ultrasound treatment at 25 and 29W, the activity of phenylalanine ammonia lyase (PAL) was increased significantly (Ppineapple was significantly (Ppineapple. Results suggest that hormetic dosage of ultrasound treatment can enhance the activity of PAL and total phenolic content and hence the total antioxidant capacity to encounter with oxidative stress. Copyright © 2016. Published by Elsevier Ltd.

  7. Effect of modulated ultrasound parameters on ultrasound-induced thrombolysis

    International Nuclear Information System (INIS)

    Soltani, Azita; Volz, Kim R; Hansmann, Doulas R

    2008-01-01

    The potential of ultrasound to enhance enzyme-mediated thrombolysis by application of constant operating parameters (COP) has been widely demonstrated. In this study, the effect of ultrasound with modulated operating parameters (MOP) on enzyme-mediated thrombolysis was investigated. The MOP protocol was applied to an in vitro model of thrombolysis. The results were compared to a COP with the equivalent soft tissue thermal index (TIS) over the duration of ultrasound exposure of 30 min (p -2 ± 0.01 μm and 1.99 x 10 -2 ± 0.004 μm, respectively (p < 0.74). No signatures of inertial or stable cavitation were observed for either acoustic protocol. In conclusion, due to mechanisms other than cavitation, application of ultrasound with modulated operating parameters has the potential to significantly enhance the relative lysis enhancement compared to application of ultrasound with constant operating parameters.

  8. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... inserted into a man's rectum to view the prostate. Transvaginal ultrasound. The transducer is inserted into a ... Stenting Ultrasound-Guided Breast Biopsy Obstetric Ultrasound Ultrasound - Prostate Biopsies - Overview Images related to General Ultrasound Videos ...

  9. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z General Ultrasound Ultrasound imaging uses sound waves to produce ... the limitations of General Ultrasound Imaging? What is General Ultrasound Imaging? Ultrasound is safe and painless, and ...

  10. Comparison of Real-Time Intraoperative Ultrasound-Based Dosimetry With Postoperative Computed Tomography-Based Dosimetry for Prostate Brachytherapy

    International Nuclear Information System (INIS)

    Nag, Subir; Shi Peipei; Liu Bingren; Gupta, Nilendu; Bahnson, Robert R.; Wang, Jian Z.

    2008-01-01

    Purpose: To evaluate whether real-time intraoperative ultrasound (US)-based dosimetry can replace conventional postoperative computed tomography (CT)-based dosimetry in prostate brachytherapy. Methods and Materials: Between December 2001 and November 2002, 82 patients underwent 103 Pd prostate brachytherapy. An interplant treatment planning system was used for real-time intraoperative transrectal US-guided treatment planning. The dose distribution was updated according to the estimated seed position to obtain the dose-volume histograms. Postoperative CT-based dosimetry was performed a few hours later using the Theraplan-Plus treatment planning system. The dosimetric parameters obtained from the two imaging modalities were compared. Results: The results of this study revealed correlations between the US- and CT-based dosimetry. However, large variations were found in the implant-quality parameters of the two modalities, including the doses covering 100%, 90%, and 80% of the prostate volume and prostate volumes covered by 100%, 150%, and 200% of the prescription dose. The mean relative difference was 38% and 16% for doses covering 100% and 90% of the prostate volume and 10% and 21% for prostate volumes covered by 100% and 150% of the prescription dose, respectively. The CT-based volume covered by 200% of the prescription dose was about 30% greater than the US-based one. Compared with CT-based dosimetry, US-based dosimetry significantly underestimated the dose to normal organs, especially for the rectum. The average US-based maximal dose and volume covered by 100% of the prescription dose for the rectum was 72 Gy and 0.01 cm 3 , respectively, much lower than the 159 Gy and 0.65 cm 3 obtained using CT-based dosimetry. Conclusion: Although dosimetry using intraoperative US-based planning provides preliminary real-time information, it does not accurately reflect the postoperative CT-based dosimetry. Until studies have determined whether US-based dosimetry or

  11. Effects of time-variable exposure regimes of the insecticide chlorpyrifos on freshwater invertebrate communities in microcosms

    NARCIS (Netherlands)

    Zafar, M.I.; Wijngaarden, van R.; Roessink, I.; Brink, van den P.J.

    2011-01-01

    The present study compared the effects of different time-variable exposure regimes having the same time-weighted average (TWA) concentration of the organophosphate insecticide chlorpyrifos on freshwater invertebrate communities to enable extrapolation of effects across exposure regimes. The

  12. Understanding the exposure-time effect on speckle contrast measurements for laser displays

    Science.gov (United States)

    Suzuki, Koji; Kubota, Shigeo

    2018-02-01

    To evaluate the influence of exposure time on speckle noise for laser displays, speckle contrast measurement method was developed observable at a human eye response time using a high-sensitivity camera which has a signal multiplying function. The nonlinearity of camera light sensitivity was calibrated to measure accurate speckle contrasts, and the measuring lower limit noise of speckle contrast was improved by applying spatial-frequency low pass filter to the captured images. Three commercially available laser displays were measured over a wide range of exposure times from tens of milliseconds to several seconds without adjusting the brightness of laser displays. The speckle contrast of raster-scanned mobile projector without any speckle-reduction device was nearly constant over various exposure times. On the contrary to this, in full-frame projection type laser displays equipped with a temporally-averaging speckle-reduction device, some of their speckle contrasts close to the lower limits noise were slightly increased at the shorter exposure time due to the noise. As a result, the exposure-time effect of speckle contrast could not be observed in our measurements, although it is more reasonable to think that the speckle contrasts of laser displays, which are equipped with the temporally-averaging speckle-reduction device, are dependent on the exposure time. This discrepancy may be attributed to the underestimation of temporal averaging factor. We expected that this method is useful for evaluating various laser displays and clarify the relationship between the speckle noise and the exposure time for a further verification of speckle reduction.

  13. Ultrasound cylindrical phased array for transoesophageal thermal therapy: initial studies

    International Nuclear Information System (INIS)

    Melodelima, David; Lafon, Cyril; Prat, Frederic; Birer, Alain; Cathignol, Dominique

    2002-01-01

    This work was undertaken to investigate the feasibility of constructing a cylindrical phased array composed of 64 elements spread around the periphery (OD 10.6 mm) for transoesophageal ultrasound thermotherapy. The underlying operating principle of this applicator is to rotate a plane ultrasound beam electronically. For this purpose, eight adjacent transducers were successively excited with appropriate delay times so as to generate a plane wave. The exposure direction was changed by exciting a different set of eight elements. For these feasibility studies, we used a cylindrical prototype (OD 10.6 mm) composed of 16 elementary transducers distributed over a quarter of the cylinder, all operating at 4.55 MHz. The active part was mechanically reinforced by a rigid damper structure behind the transducers. It was shown that an ultrasound field similar to that emitted by a plane transducer could be generated. Ex vivo experiments on pig's liver demonstrated that the ultrasound beam could be accurately rotated to generate sector-based lesions to a suitable depth (up to 19 mm). Throughout these experiments, exposures lasting 20 s were delivered at an acoustic intensity of 17 W cm -2 . By varying the power from exposure to exposure, the depth of the lesion at different angles could be controlled

  14. Feasibility of Remote Real-Time Guidance of a Cardiac Examination Performed by Novices Using a Pocket-Sized Ultrasound Device

    Directory of Open Access Journals (Sweden)

    Tuan V. Mai

    2013-01-01

    Full Text Available Background. The potential of pocket-sized ultrasound devices (PUDs to improve global healthcare delivery is limited by the lack of a suitable imaging protocol and trained users. Therefore, we investigated the feasibility of performing a brief, evidence-based cardiac limited ultrasound exam (CLUE through wireless guidance of novice users. Methods. Three trainees applied PUDs on 27 subjects while directed by an off-site cardiologist to obtain a CLUE to screen for LV systolic dysfunction (LVSD, LA enlargement (LAE, ultrasound lung comets (ULC+, and elevated CVP (eCVP. Real-time remote audiovisual guidance and interpretation by the cardiologist were performed using the iPhone 4/iPod (FaceTime, Apple, Inc. attached to the PUD and transmitted data wirelessly. Accuracy and technical quality of transmitted images were compared to on-site, gold-standard echo thresholds. Results. Novice versus sonographer imaging yielded technically adequate views in 122/135 (90% versus 130/135 (96% (. CLUE’s combined SN, SP, and ACC were 0.67, 0.96, and 0.90. Technical adequacy (% and accuracy for each abnormality ( were LVSD (85%, 0.93, , LAE (89%, 0.74, , ULC+ (100%, 0.94, , and eCVP (78%, 0.91, . Conclusion. A novice can perform the CLUE using PUD when wirelessly guided by an expert. This method could facilitate PUD use for off-site bedside medical decision making and triaging of patients.

  15. Crucial factors and emerging concepts in ultrasound-triggered drug delivery.

    Science.gov (United States)

    Geers, Bart; Dewitte, Heleen; De Smedt, Stefaan C; Lentacker, Ine

    2012-12-28

    Time and space controlled drug delivery still remains a huge challenge in medicine. A novel approach that could offer a solution is ultrasound guided drug delivery. “Ultrasonic drug delivery” is often based on the use of small gas bubbles (so-called microbubbles) that oscillate and cavitate upon exposure to ultrasound waves. Some microbubbles are FDA approved contrast agents for ultrasound imaging and are nowadays widely investigated as promising drug carriers. Indeed, it has been observed that upon exposure to ultrasound waves, microbubbles may (a) release the encapsulated drugs and (b) simultaneously change the structure of the cell membranes in contact with the microbubbles which may facilitate drug entrance into cells. This review aims to highlight (a) major factors known so far which affect ultrasonic drug delivery (like the structure of the microbubbles, acoustic settings, etc.) and (b) summarizes the recent preclinical progress in this field together with a number of promising new concepts and applications.

  16. Analysis of real-time mixture cytotoxicity data following repeated exposure using BK/TD models

    International Nuclear Information System (INIS)

    Teng, S.; Tebby, C.; Barcellini-Couget, S.; De Sousa, G.; Brochot, C.; Rahmani, R.; Pery, A.R.R.

    2016-01-01

    Cosmetic products generally consist of multiple ingredients. Thus, cosmetic risk assessment has to deal with mixture toxicity on a long-term scale which means it has to be assessed in the context of repeated exposure. Given that animal testing has been banned for cosmetics risk assessment, in vitro assays allowing long-term repeated exposure and adapted for in vitro – in vivo extrapolation need to be developed. However, most in vitro tests only assess short-term effects and consider static endpoints which hinder extrapolation to realistic human exposure scenarios where concentration in target organs is varies over time. Thanks to impedance metrics, real-time cell viability monitoring for repeated exposure has become possible. We recently constructed biokinetic/toxicodynamic models (BK/TD) to analyze such data (Teng et al., 2015) for three hepatotoxic cosmetic ingredients: coumarin, isoeugenol and benzophenone-2. In the present study, we aim to apply these models to analyze the dynamics of mixture impedance data using the concepts of concentration addition and independent action. Metabolic interactions between the mixture components were investigated, characterized and implemented in the models, as they impacted the actual cellular exposure. Indeed, cellular metabolism following mixture exposure induced a quick disappearance of the compounds from the exposure system. We showed that isoeugenol substantially decreased the metabolism of benzophenone-2, reducing the disappearance of this compound and enhancing its in vitro toxicity. Apart from this metabolic interaction, no mixtures showed any interaction, and all binary mixtures were successfully modeled by at least one model based on exposure to the individual compounds. - Highlights: • We could predict cell response over repeated exposure to mixtures of cosmetics. • Compounds acted independently on the cells. • Metabolic interactions impacted exposure concentrations to the compounds.

  17. Analysis of real-time mixture cytotoxicity data following repeated exposure using BK/TD models

    Energy Technology Data Exchange (ETDEWEB)

    Teng, S.; Tebby, C. [Models for Toxicology and Ecotoxicology Unit, INERIS, Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Barcellini-Couget, S. [ODESIA Neosciences, Sophia Antipolis, 400 route des chappes, 06903 Sophia Antipolis (France); De Sousa, G. [INRA, ToxAlim, 400 route des Chappes, BP, 167 06903 Sophia Antipolis, Cedex (France); Brochot, C. [Models for Toxicology and Ecotoxicology Unit, INERIS, Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Rahmani, R. [INRA, ToxAlim, 400 route des Chappes, BP, 167 06903 Sophia Antipolis, Cedex (France); Pery, A.R.R., E-mail: alexandre.pery@agroparistech.fr [AgroParisTech, UMR 1402 INRA-AgroParisTech Ecosys, 78850 Thiverval Grignon (France); INRA, UMR 1402 INRA-AgroParisTech Ecosys, 78850 Thiverval Grignon (France)

    2016-08-15

    Cosmetic products generally consist of multiple ingredients. Thus, cosmetic risk assessment has to deal with mixture toxicity on a long-term scale which means it has to be assessed in the context of repeated exposure. Given that animal testing has been banned for cosmetics risk assessment, in vitro assays allowing long-term repeated exposure and adapted for in vitro – in vivo extrapolation need to be developed. However, most in vitro tests only assess short-term effects and consider static endpoints which hinder extrapolation to realistic human exposure scenarios where concentration in target organs is varies over time. Thanks to impedance metrics, real-time cell viability monitoring for repeated exposure has become possible. We recently constructed biokinetic/toxicodynamic models (BK/TD) to analyze such data (Teng et al., 2015) for three hepatotoxic cosmetic ingredients: coumarin, isoeugenol and benzophenone-2. In the present study, we aim to apply these models to analyze the dynamics of mixture impedance data using the concepts of concentration addition and independent action. Metabolic interactions between the mixture components were investigated, characterized and implemented in the models, as they impacted the actual cellular exposure. Indeed, cellular metabolism following mixture exposure induced a quick disappearance of the compounds from the exposure system. We showed that isoeugenol substantially decreased the metabolism of benzophenone-2, reducing the disappearance of this compound and enhancing its in vitro toxicity. Apart from this metabolic interaction, no mixtures showed any interaction, and all binary mixtures were successfully modeled by at least one model based on exposure to the individual compounds. - Highlights: • We could predict cell response over repeated exposure to mixtures of cosmetics. • Compounds acted independently on the cells. • Metabolic interactions impacted exposure concentrations to the compounds.

  18. [Basics of emergency ultrasound].

    Science.gov (United States)

    Schellhaas, S; Breitkreutz, R

    2012-09-05

    Focused ultrasound is a key methodology of critical care medicine. By referencing few ultrasound differential diagnosis, it is possible to identifying in real-time the reason of the critical state of a patient. Therefore typical focused ultrasound protocols were developed. The well known Focused Assessment with Sonography for trauma (FAST) was incorporated into the Advanced Trauma Life Support (ATLS) for shock room. Focused echocardiographic evaluation in life support (FEEL) has been designed to be conformed with the universal Advanced Life Support (ALS) algorithm and to identify treatable conditions such as acute right ventricular pressure overload in pulmonary embolism, hypovolemia, or pericardial effusion/tamponade. Using lung ultrasound one can differentiate pulmonary edema, pleural effusion or pneumothorax.

  19. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Ultrasound - Pelvis Ultrasound imaging of the pelvis uses sound waves to ...

  20. Interventional ultrasound

    International Nuclear Information System (INIS)

    VanSonnenberg, E.

    1987-01-01

    This book contains 12 chapters and several case studies. Some of the chapter titles are: The Interplay of Ultrasound and Computed Tomography in the Planning and Execution of Interventional Procedures: Ulltrasound Guided Biopsy; Interventioal Genitourinary Sonography; Diagnosis and Treatment of Pericardial Effusion Using Ultrasonic Guidance; and New Ultrasound-Guided Interventional Procedures--Cholecystostomy, Pancreatography, Gastrostomy

  1. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Ultrasound - Pelvis Ultrasound imaging ...

  2. Prostate Ultrasound

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Ultrasound - Prostate Ultrasound of ...

  3. Ultrasound stethoscopy

    NARCIS (Netherlands)

    E.C. Vourvouri (Eleni)

    2002-01-01

    textabstractIn this thesis we repmi the many evaluation studies with the hand-held ultrasound device in the assessment of different cardiac pathologies and in different clinical settings. The reason for using the tetm "ultrasound stethoscopy" is that these devices are augmenting our

  4. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... to-use and less expensive than other imaging methods. Ultrasound imaging is extremely safe and does not use any ionizing radiation. Ultrasound scanning gives a clear picture of soft tissues that do not show up well on ...

  5. Biological effects of low frequency high intensity ultrasound application on ex vivo human adipose tissue.

    Science.gov (United States)

    Palumbo, P; Cinque, B; Miconi, G; La Torre, C; Zoccali, G; Vrentzos, N; Vitale, A R; Leocata, P; Lombardi, D; Lorenzo, C; D'Angelo, B; Macchiarelli, G; Cimini, A; Cifone, M G; Giuliani, M

    2011-01-01

    In the present work the effects of a new low frequency, high intensity ultrasound technology on human adipose tissue ex vivo were studied. In particular, we investigated the effects of both external and surgical ultrasound-irradiation (10 min) by evaluating, other than sample weight loss and fat release, also histological architecture alteration as well apoptosis induction. The influence of saline buffer tissue-infiltration on the effects of ultrasound irradiation was also examined. The results suggest that, in our experimental conditions, both transcutaneous and surgical ultrasound exposure caused a significant weight loss and fat release. This effect was more relevant when the ultrasound intensity was set at 100 % (~2.5 W/cm², for external device; ~19-21 W/cm2, for surgical device) compared to 70 % (~1.8 W/cm² for external device; ~13-14 W/cm2 for surgical device). Of note, the effectiveness of ultrasound was much higher when the tissue samples were previously infiltrated with saline buffer, in accordance with the knowledge that ultrasonic waves in aqueous solution better propagate with a consequently more efficient cavitation process. Moreover, the overall effects of ultrasound irradiation did not appear immediately after treatment but persisted over time, being significantly more relevant at 18 h from the end of ultrasound irradiation. Evaluation of histological characteristics of ultrasound-irradiated samples showed a clear alteration of adipose tissue architecture as well a prominent destruction of collagen fibers which were dependent on ultrasound intensity and most relevant in saline buffer-infiltrated samples. The structural changes of collagen bundles present between the lobules of fat cells were confirmed through scanning electron microscopy (SEM) which clearly demonstrated how ultrasound exposure induced a drastic reduction in the compactness of the adipose connective tissue and an irregular arrangement of the fibers with a consequent alteration in

  6. Effect of smoking on the radon risk in dependence on the time elapsed from exposure

    International Nuclear Information System (INIS)

    Boehm, Radoslav; Holy, Karol; Sedlak, A.

    2013-01-01

    The synergistic effect of cigarette smoking and radon exposure on the lung cancer risk was assessed by using the threshold energy model, which allows the biological effects of radon daughter products on the lung tissue to be analyzed. The shape of the curves describing the relation between the risk and the time after exposure was estimated. The change in the lung function caused by chronic smoking was considered in the calculations. (orig.)

  7. Children's (Pediatric) Abdominal Ultrasound Imaging

    Medline Plus

    Full Text Available ... the patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... of vomiting in young infants Because ultrasound provides real-time images, images that are renewed continuously, it also ...

  8. Long term exposure to respirable volcanic ash on Montserrat: a time series simulation

    Science.gov (United States)

    Hincks, T. K.; Aspinall, W. P.; Baxter, P. J.; Searl, A.; Sparks, R. S. J.; Woo, G.

    2006-01-01

    Frequent ash fallout from long-lived eruptions (with active phases greater than 5 years) may lead to local populations experiencing unacceptably high cumulative exposures to respirable particulate matter. Ash from Montserrat has been shown to contain significant levels of cristobalite and other reactive agents that are associated with an increased risk of developing pneumoconiosis (including silicosis) and other long-term health problems. There are a number of difficulties associated with estimating risks in populations due to uncertain and wide ranging individual exposures, change in behaviour with time and the natural variation in individual response. Present estimates of risk in workers and other population groups are simplifications based on a limited number of exposure measurements taken on Montserrat (1996-1999), and exposure-response curves from epidemiological studies of coal workers exposed to siliceous dust. In this paper we present a method for calculating the long-term cumulative exposure to cristobalite from volcanic ash by Monte Carlo simulation. Code has been written to generate synthetic time series for volcanic activity, rainfall, ash deposition and erosion to give daily ash deposit values and cristobalite fraction at a range of locations. The daily mean personal exposure for PM10 and cristobalite is obtained by sampling from a probability distribution, with distribution parameters dependent on occupation, ground deposit depth and daily weather conditions. Output from multiple runs is processed to calculate the exceedance probability for cumulative exposure over a range of occupation types, locations and exposure periods. Results are interpreted in terms of current occupational standards, and epidemiological exposure-response functions for silicosis are applied to quantify the long-term health risk. Assuming continuing volcanic activity, median risk of silicosis (profusion 1/0 or higher) for an average adult after 20 years continuous exposure is

  9. Investigating the American Time Use Survey from an Exposure Modeling Perspective

    Science.gov (United States)

    This paper describes an evaluation of the U.S. Bureau of Labor Statistics' American Time Use Survey (ATUS) for potential use in modeling human exposures to environmental pollutants. The ATUS is a large, on-going, cross-sectional survey of where Americans spend time and what activ...

  10. The Effects of Ultrasound on Biological Systems: Site

    Science.gov (United States)

    El-Karmi, Anan M.

    Earlier studies (Dinno et al., Ultrasound Med. Biol. 15:461 -470; 1989) demonstrated that ultrasound at therapeutic intensities causes large increases in total conductance (G_{rm t}) of frog skin. These changes were attributed to non-thermal mechanisms, primarily, cavitation. In this study, the site(s) and mechanism(s) of action of ultrasound for the increase in G_{rm t} were examined. The reversible changes in G_{rm t } and sodium current were monitored in real time as a function of ultrasound exposure. Amiloride, a sodium channel blocker, was used to differentiate between cellular (G_{rm c}) and paracellular (G_{rm s}) pathways in the presence and absence of ultrasound. No significant changes were detected in G_ {rm c}. However, changes in G _{rm s} were significant. These results demonstrate that most of the increase in G _{rm t} due to ultrasound is taking place in the paracellular pathways. Sodium channels were not significantly affected by ultrasound. Thus, the changes in G_{rm c} are not specific. The effects of ultrasound were examined in the presence of radical scavengers and antioxidants. The increase in G_{rm t} due to ultrasound was significantly minimized in the presence of cystamine, cysteamine, and sodium ascorbate. This demonstrates that free radicals and other reactive species generated by cavitation are causing the increase in G_ {rm t}, possibly by acting from inside the cells. Radical scavengers and antioxidants are providing protection from oxidative damage but are not involved in the recovery of G_{ rm t} towards steady state values after sonication. The role of Ca^{2+} in the effects of ultrasound was examined since many of the cellular reactions involved in tissue recovery are dependent on the intracellular availability of free Ca^{2+}. The percentage increase in G_{rm t} in the presence of Ca^{2+} was larger than in its absence (140% vs. 27%). The time constant for G_{rm t} to return to steady state was longer in calcium-free solutions (122

  11. Improving the Image Quality of Synthetic Transmit Aperture Ultrasound Images - Achieving Real-Time In-Vivo Imaging

    DEFF Research Database (Denmark)

    Gammelmark, Kim

    in-vivo experiments, showed, that TMS imaging can increase the SNR by as much as 17 dB compared to the traditional imaging techniques, which improves the in-vivo image quality to a highly competitive level. An in-vivo evaluation of convex array TMS imaging for abdominal imaging applications......-vivo imaging, and that the obtained image quality is highly competitive with the techniques applied in current medical ultrasound scanners. Hereby, the goals of the PhD have been successfully achieved.......Synthetic transmit aperture (STA) imaging has the potential to increase the image quality of medical ultrasound images beyond the levels obtained by conventional imaging techniques (linear, phased, and convex array imaging). Currently, however, in-vivo applications of STA imaging is limited...

  12. Standardized ultrasound templates for diagnosing appendicitis reduce annual imaging costs.

    Science.gov (United States)

    Nordin, Andrew B; Sales, Stephen; Nielsen, Jason W; Adler, Brent; Bates, David Gregory; Kenney, Brian

    2018-01-01

    Ultrasound is preferred over computed tomography (CT) for diagnosing appendicitis in children to avoid undue radiation exposure. We previously reported our experience in instituting a standardized appendicitis ultrasound template, which decreased CT rates by 67.3%. In this analysis, we demonstrate the ongoing cost savings associated with using this template. Retrospective chart review for the time period preceding template implementation (June 2012-September 2012) was combined with prospective review through December 2015 for all patients in the emergency department receiving diagnostic imaging for appendicitis. The type of imaging was recorded, and imaging rates and ultrasound test statistics were calculated. Estimated annual imaging costs based on pretemplate ultrasound and CT utilization rates were compared with post-template annual costs to calculate annual and cumulative savings. In the pretemplate period, ultrasound and CT rates were 80.2% and 44.3%, respectively, resulting in a combined annual cost of $300,527.70. Similar calculations were performed for each succeeding year, accounting for changes in patient volume. Using pretemplate rates, our projected 2015 imaging cost was $371,402.86; however, our ultrasound rate had increased to 98.3%, whereas the CT rate declined to 9.6%, yielding an annual estimated cost of $224,853.00 and a savings of $146,549.86. Since implementation, annual savings have steadily increased for a cumulative cost savings of $336,683.83. Standardizing ultrasound reports for appendicitis not only reduces the use of CT scans and the associated radiation exposure but also decreases annual imaging costs despite increased numbers of imaging studies. Continued cost reduction may be possible by using diagnostic algorithms. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Non-linear behaviour of power density and exposure time of argon laser on ocular tissues

    Energy Technology Data Exchange (ETDEWEB)

    El-Sayed, E M; Talaat, M S; Salem, E F [Physics Department, Faculty of Science, Ain Shams University, Cairo (Egypt)

    1997-12-31

    In ophthalmology, the thermal effect of argon laser is the most widely used category of laser- tissue interaction. The rise in tissue temperature has to exceed a threshold value for photo coagulation of retinal blood vessels. This value mainly depends on the laser. The most suitable argon laser power P and exposure time (t) which would be more effective for thermal and electrical behaviour of chicken eye was studied. This was achieved by measuring the variations in ocular temperature in electroretinogram (ERG) records under the effect of argon experiment, while power density (P) and exposure time (t) were varied in four different ways for each dose (pt). Results indicated that for the same laser dose, the temperature distribution of the eye, using low power density and high exposure time was higher than that high power density and low exposure time, indicating non-linearity of the laser dose. This finding was confirmed by ERG records which showed similar variations in b-wave latency, amplitude and duration, for the laser exposure conditions. This indicates variations in retinal function due to laser-dependent temperature variations. 5 figs., 3 tabs.

  14. Real-time ultrasound imaging of irreversible electroporation in a porcine liver model adequately characterizes the zone of cellular necrosis.

    Science.gov (United States)

    Schmidt, Carl R; Shires, Peter; Mootoo, Mary

    2012-02-01

      Irreversible electroporation (IRE) is a largely non-thermal method for the ablation of solid tumours. The ability of ultrasound (US) to measure the size of the IRE ablation zone was studied in a porcine liver model.   Three normal pig livers were treated in vivo with a total of 22 ablations using IRE. Ultrasound was used within minutes after ablation and just prior to liver harvest at either 6 h or 24 h after the procedure. The area of cellular necrosis was measured after staining with nitroblue tetrazolium and the percentage of cell death determined by histomorphometry.   Visible changes in the hepatic parenchyma were apparent by US after all 22 ablations using IRE. The mean maximum diameter of the ablation zone measured by US during the procedure was 20.1 ± 2.7 mm. This compared with a mean cellular necrosis zone maximum diameter of 20.3 ± 2.9 mm as measured histologically. The mean percentage of dead cells within the ablation zone was 77% at 6 h and 98% at 24 h after ablation.   Ultrasound is a useful modality for measuring the ablation zone within minutes of applying IRE to normal liver tissue. The area of parenchymal change measured by US correlates with the area of cellular necrosis. © 2011 International Hepato-Pancreato-Biliary Association.

  15. Odors: appetizing or satiating? Development of appetite during odor exposure over time.

    Science.gov (United States)

    Ramaekers, M G; Boesveldt, S; Lakemond, C M M; van Boekel, M A J S; Luning, P A

    2014-05-01

    Exposure to palatable food odors influences appetite responses, either promoting or inhibiting food intake. Possibly, food odors are appetizing after a short exposure (of circa 1-3 min), but become satiating over time (circa 10-20 min). To investigate the effect of odor exposure on general appetite and sensory-specific appetite (SSA) over time. In a cross-over study, 21 unrestrained women (age: 18-45 years; BMI: 18.5-25 kg m(-2)) were exposed for 20 min to eight different odor types: five food odors, two nonfood odors and no-odor. All odors were distributed in a test room at suprathreshold levels. General appetite, SSA and salivation were measured over time. All food odors significantly increased general appetite and SSA, compared with the no-odor condition. The nonfood odors decreased general appetite. All effects did not change over time during odor exposure. Savory odors increased the appetite for savory foods, but decreased appetite for sweet foods, and vice versa after exposure to sweet odors. Neither food odors nor nonfood odors affected salivation. Palatable food odors were appetizing during and after odor exposure and did not become satiating over a 20-min period. Food odors had a large impact on SSA and a small impact on general appetite. Moreover, exposure to food odors increased the appetite for congruent foods, but decreased the appetite for incongruent foods. It may be hypothesized that, once the body is prepared for intake of a certain food with a particular macronutrient composition, it is unfavorable to consume foods that are very different from the cued food.

  16. Radiation exposure and examination time during enteroclysis and small bowel follow-through

    International Nuclear Information System (INIS)

    Thoeni, R.F.; Gould, R.G.

    1989-01-01

    The authors have investigated radiation exposures and total examination and fluoroscopy times in enterolysis and small-bowel-follow-through (SBFT). Enteroclysis was performed in 25 patients and SBFT in another 25 (17 with UGI/SBFT and 8 with SBFT alone), with 5 TLD dosimeters placed in areas of the back exposed to primary x-rays during fluoroscopy, spot, and overhead radiography. Skin entry exposures, fluoroscopy, and total examination times in enteroclysis were compared to those in SBFTs. Biphasic enteroclyis was performed, with an average of 18 radiographs per study, SBFT with 16, and UGI/SBFT with 23. Indications and pathology for enteroclysis and SBFT were similar. Detailed findings are presented. The authors conclude that total examination time for enteroclysis is two to three times shorter and skin entry exposure is less than two to three times higher than for SBFT. Higher radiation exposure of enteroclysis should be weighted against very short examination times and reported high accuracy in deciding between enteroclysis and SBFT

  17. Chronic ethanol exposure produces time- and brain region-dependent changes in gene coexpression networks.

    Directory of Open Access Journals (Sweden)

    Elizabeth A Osterndorff-Kahanek

    Full Text Available Repeated ethanol exposure and withdrawal in mice increases voluntary drinking and represents an animal model of physical dependence. We examined time- and brain region-dependent changes in gene coexpression networks in amygdala (AMY, nucleus accumbens (NAC, prefrontal cortex (PFC, and liver after four weekly cycles of chronic intermittent ethanol (CIE vapor exposure in C57BL/6J mice. Microarrays were used to compare gene expression profiles at 0-, 8-, and 120-hours following the last ethanol exposure. Each brain region exhibited a large number of differentially expressed genes (2,000-3,000 at the 0- and 8-hour time points, but fewer changes were detected at the 120-hour time point (400-600. Within each region, there was little gene overlap across time (~20%. All brain regions were significantly enriched with differentially expressed immune-related genes at the 8-hour time point. Weighted gene correlation network analysis identified modules that were highly enriched with differentially expressed genes at the 0- and 8-hour time points with virtually no enrichment at 120 hours. Modules enriched for both ethanol-responsive and cell-specific genes were identified in each brain region. These results indicate that chronic alcohol exposure causes global 'rewiring' of coexpression systems involving glial and immune signaling as well as neuronal genes.

  18. Analysis of real-time mixture cytotoxicity data following repeated exposure using BK/TD models.

    Science.gov (United States)

    Teng, S; Tebby, C; Barcellini-Couget, S; De Sousa, G; Brochot, C; Rahmani, R; Pery, A R R

    2016-08-15

    Cosmetic products generally consist of multiple ingredients. Thus, cosmetic risk assessment has to deal with mixture toxicity on a long-term scale which means it has to be assessed in the context of repeated exposure. Given that animal testing has been banned for cosmetics risk assessment, in vitro assays allowing long-term repeated exposure and adapted for in vitro - in vivo extrapolation need to be developed. However, most in vitro tests only assess short-term effects and consider static endpoints which hinder extrapolation to realistic human exposure scenarios where concentration in target organs is varies over time. Thanks to impedance metrics, real-time cell viability monitoring for repeated exposure has become possible. We recently constructed biokinetic/toxicodynamic models (BK/TD) to analyze such data (Teng et al., 2015) for three hepatotoxic cosmetic ingredients: coumarin, isoeugenol and benzophenone-2. In the present study, we aim to apply these models to analyze the dynamics of mixture impedance data using the concepts of concentration addition and independent action. Metabolic interactions between the mixture components were investigated, characterized and implemented in the models, as they impacted the actual cellular exposure. Indeed, cellular metabolism following mixture exposure induced a quick disappearance of the compounds from the exposure system. We showed that isoeugenol substantially decreased the metabolism of benzophenone-2, reducing the disappearance of this compound and enhancing its in vitro toxicity. Apart from this metabolic interaction, no mixtures showed any interaction, and all binary mixtures were successfully modeled by at least one model based on exposure to the individual compounds. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Integration of image exposure time into a modified laser speckle imaging method

    Energy Technology Data Exchange (ETDEWEB)

    RamIrez-San-Juan, J C; Salazar-Hermenegildo, N; Ramos-Garcia, R; Munoz-Lopez, J [Optics Department, INAOE, Puebla (Mexico); Huang, Y C [Department of Electrical Engineering and Computer Science, University of California, Irvine, CA (United States); Choi, B, E-mail: jcram@inaoep.m [Beckman Laser Institute and Medical Clinic, University of California, Irvine, CA (United States)

    2010-11-21

    Speckle-based methods have been developed to characterize tissue blood flow and perfusion. One such method, called modified laser speckle imaging (mLSI), enables computation of blood flow maps with relatively high spatial resolution. Although it is known that the sensitivity and noise in LSI measurements depend on image exposure time, a fundamental disadvantage of mLSI is that it does not take into account this parameter. In this work, we integrate the exposure time into the mLSI method and provide experimental support of our approach with measurements from an in vitro flow phantom.

  20. Integration of image exposure time into a modified laser speckle imaging method

    International Nuclear Information System (INIS)

    RamIrez-San-Juan, J C; Salazar-Hermenegildo, N; Ramos-Garcia, R; Munoz-Lopez, J; Huang, Y C; Choi, B

    2010-01-01

    Speckle-based methods have been developed to characterize tissue blood flow and perfusion. One such method, called modified laser speckle imaging (mLSI), enables computation of blood flow maps with relatively high spatial resolution. Although it is known that the sensitivity and noise in LSI measurements depend on image exposure time, a fundamental disadvantage of mLSI is that it does not take into account this parameter. In this work, we integrate the exposure time into the mLSI method and provide experimental support of our approach with measurements from an in vitro flow phantom.

  1. [Ultrasound physiotherapy treatment of prostatitis].

    Science.gov (United States)

    Talberg, P I; Andryukhin, M I; Mazina, S E; Nikolaev, A L

    2016-12-01

    Develop a method of treatment of prostatitis based on the use of a standard antibiotic, immunomodulatory therapy, and transrectal ultrasound physiotherapy. The dynamics of the accumulation of the antibiotic was investigated in male rats. Sonication was performed immediately before the administration of the antibiotic and its accumulation in the process at 10, 20, 40, 60, 80, 100 min after dosing. The clinical study included 138 patients with chronic prostatitis. Patients of the experimental group, in addition to standard therapy, 10 sessions of transrectal ultrasound physical therapy was performed. The efficacy of treatment was assessed after 14 and 28 days after initiation. and its discussion. Experiments on laboratory animals have shown that the highest concentration and the residence time of antibiotic in the prostate tissue is noted ultrasonic treatment in the period of maximum blood concentration of the test drug. The data obtained allow to determine that the ultrasonic treatment must be performed considering the pharmacokinetics of the antibiotic. In conducting clinical trials on day 14 of treatment and clinical manifestations of prostatitis bacterial microflora in prostatic secretions were no patients in both groups. In 15% of patients of the experimental group the number of leukocytes decreased to the normal range. After 28 days the amount of leukocytes was normal in 51% of patients in the control and 85% in the experimental group. In animal experiments defined the optimal time interval separating the moment of injection of the antibiotic from the beginning of sonication. Clinical studies have shown that the transrectal ultrasound exposure during the period of maximum concentration of the antibiotic in the blood, improves patient outcomes by 33.8%.

  2. Fetal Ultrasound

    Science.gov (United States)

    ... isn't recommended simply to determine a baby's sex. Similarly, fetal ultrasound isn't recommended solely for the purpose of producing keepsake videos or pictures. If your health care provider doesn' ...

  3. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... and movement of the body's internal organs, as well as blood flowing through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. ...

  4. Prostate Ultrasound

    Medline Plus

    Full Text Available ... and movement of the body's internal organs, as well as blood flowing through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. ...

  5. Prostate Ultrasound

    Medline Plus

    Full Text Available ... requested the exam. Usually, the referring physician or health care provider will share the results with you. ... well on x-ray images. Ultrasound causes no health problems and may be repeated as often as ...

  6. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... ultrasound exams are also used to monitor the health and development of an embryo or fetus during ... requested the exam. Usually, the referring physician or health care provider will share the results with you. ...

  7. Prostate Ultrasound

    Medline Plus

    Full Text Available ... probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ... the transducer (the device placed on the patient's skin to send and receive the returning sound waves), ...

  8. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ... the transducer (the device placed on the patient's skin to send and receive the returning sound waves), ...

  9. Prostate Ultrasound

    Medline Plus

    Full Text Available ... no ionizing radiation. Ultrasound scanning may be able to give a clearer picture of soft tissues that do ... understanding of the possible charges you will incur. Web page review process: This Web page is reviewed ...

  10. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... collects the sounds that bounce back and a computer then uses those sound waves to create an ... Ultrasound scanners consist of a console containing a computer and electronics, a video display screen and a ...

  11. Prostate Ultrasound

    Medline Plus

    Full Text Available ... collects the sounds that bounce back and a computer then uses those sound waves to create an ... Ultrasound scanners consist of a console containing a computer and electronics, a video display screen and a ...

  12. Prostate Ultrasound

    Medline Plus

    Full Text Available ... sends out high-frequency sound waves (that the human ear cannot hear) into the body and then ... ultrasound , there are no known harmful effects on humans. top of page What are the limitations of ...

  13. Prostate Ultrasound

    Medline Plus

    Full Text Available ... is located directly in front of the rectum, so the ultrasound exam is performed transrectally in order ... A follow-up examination may also be necessary so that any change in a known abnormality can ...

  14. Prostate Ultrasound

    Medline Plus

    Full Text Available ... the rectal wall is relatively insensitive to the pain in the region of the prostate. A biopsy ... needle biopsies and fluid aspiration. Risks For standard diagnostic ultrasound , there are no known harmful effects on ...

  15. Prostate Ultrasound

    Medline Plus

    Full Text Available ... diagnose symptoms such as difficulty urinating or an elevated blood test result. It’s also used to investigate ... physical exam or prostate cancer screening exam. an elevated blood test result. difficulty urinating. Because ultrasound provides ...

  16. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... The principles are similar to sonar used by boats and submarines. The ultrasound image is immediately visible ... principles involved in the sonar used by bats, ships and fishermen. When a sound wave strikes an ...

  17. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... areas of the body while other areas, especially air-filled lungs, are poorly suited for ultrasound. For ... make secure contact with the body and eliminate air pockets between the transducer and the skin that ...

  18. Prostate Ultrasound

    Medline Plus

    Full Text Available ... a follow-up exam is done because a potential abnormality needs further evaluation with additional views or ... of soft tissues that do not show up well on x-ray images. Ultrasound causes no health ...

  19. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... a follow-up exam is done because a potential abnormality needs further evaluation with additional views or ... of soft tissues that do not show up well on x-ray images. Ultrasound is the preferred ...

  20. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... is smaller than the standard speculum used when performing a Pap test . A protective cover is placed ... of soft tissues that do not show up well on x-ray images. Ultrasound is the preferred ...

  1. Prostate Ultrasound

    Medline Plus

    Full Text Available ... scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on ... to do the scanning. The transducer is a small hand-held device that resembles a microphone, attached ...

  2. Ultrasound -- Pelvis

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    Full Text Available ... scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on ... the child prior to the exam. Bringing books, small toys, music or games can help to distract ...

  3. Ultrasound -- Pelvis

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    Full Text Available ... arteries and veins in the abdomen, arms, legs, neck and/or brain (in infants and children) or ... diagnose symptoms experienced by women such as: pelvic pain abnormal vaginal bleeding other menstrual problems Ultrasound exams ...

  4. Prostate Ultrasound

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    Full Text Available ... gel. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... the best way to see if treatment is working or if a finding is stable or changed ...

  5. Ultrasound -- Pelvis

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    Full Text Available ... and development of an embryo or fetus during pregnancy. See the Obstetrical Ultrasound page for more information . ... move through vessels. The movement of blood cells causes a change in pitch of the reflected sound ...

  6. Ultrasound -- Pelvis

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    Full Text Available ... to-use and less expensive than other imaging methods. Ultrasound imaging is extremely safe and does not ... barium exams, CT scanning , and MRI are the methods of choice in such a setting. Large patients ...

  7. Ultrasound -- Pelvis

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    Full Text Available ... insertion. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... move through vessels. The movement of blood cells causes a change in pitch of the reflected sound ...

  8. Prostate Ultrasound

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    Full Text Available ... gel. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... requested the exam. Usually, the referring physician or health care provider will share the results with you. ...

  9. Ultrasound -- Pelvis

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    Full Text Available ... insertion. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... requested the exam. Usually, the referring physician or health care provider will share the results with you. ...

  10. Ultrasound imaging

    International Nuclear Information System (INIS)

    Wells, P.N.T.

    1983-01-01

    Ultrasound is a form of energy which consists of mechanical vibrations the frequencies of which are so high that they are above the range of human hearing. The lower frequency limit of the ultrasonic spectrum may generally be taken to be about 20 kHz. Most biomedical applications of ultrasound employ frequencies in the range 1-15 MHz. At these frequencies, the wavelength is in the range 1.5 - 0.1 mm in soft tissues, and narrow beams of ultrasound can be generated which propagate through such tissues without excessive attenuation. This chapter begins with brief reviews of the physics of diagnostic ultrasound pulse-echo imaging methods and Doppler imaging methods. The remainder of the chapter is a resume of the applications of ultrasonic imaging to physiological measurement

  11. Ultrasound -- Pelvis

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    Full Text Available ... be asked to drink water prior to the examination to fill your bladder. Leave jewelry at home ... those sound waves to create an image. Ultrasound examinations do not use ionizing radiation (as used in ...

  12. Prostate Ultrasound

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    Full Text Available ... top of page Additional Information and Resources RTAnswers.org Radiation Therapy for Prostate Cancer top of page ... to Ultrasound - Prostate Sponsored by Please note RadiologyInfo.org is not a medical facility. Please contact your ...

  13. Prostate Ultrasound

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    Full Text Available ... with measurements acquired as needed for any treatment planning. detect an abnormal growth within the prostate. help ... end of their bowel (rectum) removed during prior surgery are not good candidates for ultrasound of the ...

  14. Prostate Ultrasound

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    Full Text Available ... prostate gland and to help diagnose symptoms such as difficulty urinating or an elevated blood test result. ... image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is no ...

  15. Ultrasound -- Pelvis

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    Full Text Available ... in the abdomen, arms, legs, neck and/or brain (in infants and children) or within various body organs ... or uterine cancers A transvaginal ultrasound is usually performed to view ...

  16. Prostate Ultrasound

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    Full Text Available ... is enlarged, also known as benign prostatic hyperplasia (BPH) , with measurements acquired as needed for any treatment ... caption Related Articles and Media Benign Prostatic Hyperplasia (BPH) (Enlargement of the Prostate) Prostate Cancer Ultrasound- and ...

  17. Ultrasound -- Pelvis

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    Full Text Available ... uterine cavity . Three-dimensional (3-D) ultrasound permits evaluation of the uterus and ovaries in planes that ... a special study usually done to provide detailed evaluation of the prostate gland, involves inserting a specialized ...

  18. Prostate Ultrasound

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    Full Text Available ... needle biopsies and fluid aspiration. Risks For standard diagnostic ultrasound , there are no known harmful effects on ... and Resources RTAnswers.org Radiation Therapy for Prostate Cancer top of page This page was reviewed on ...

  19. Prostate Ultrasound

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    Full Text Available ... rectum. top of page What are some common uses of the procedure? A transrectal ultrasound of the ... is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. ...

  20. Ultrasound -- Pelvis

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    Full Text Available ... legs, neck and/or brain (in infants and children) or within various body organs such as the ... tumors other disorders of the urinary bladder In children, pelvic ultrasound can help evaluate: pelvic masses pelvic ...

  1. Ultrasound -- Pelvis

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    Full Text Available ... uterus). Sonohysterography allows for a more in-depth investigation of the uterine cavity . Three-dimensional (3-D) ... to-use and less expensive than other imaging methods. Ultrasound imaging is extremely safe and does not ...

  2. Ultrasound -- Pelvis

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    Full Text Available ... is Pelvic Ultrasound Imaging? What are some common uses of the procedure? How should I prepare? What does the equipment look like? How does the procedure work? How is the procedure performed? What will I ...

  3. Ultrasound -- Pelvis

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    Full Text Available ... quickly. The ultrasound exam room may have a television. Feel free to ask for your child's favorite ... display screen that looks like a computer or television monitor. The image is created based on the ...

  4. Prostate Ultrasound

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    Full Text Available ... Images related to Ultrasound - Prostate Sponsored by Please note RadiologyInfo.org is not a medical facility. Please ... is further reviewed by committees from the American College of Radiology (ACR) and the Radiological Society of ...

  5. Ultrasound -- Pelvis

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    Full Text Available ... Images related to Ultrasound - Pelvis Sponsored by Please note RadiologyInfo.org is not a medical facility. Please ... is further reviewed by committees from the American College of Radiology (ACR) and the Radiological Society of ...

  6. Ultrasound -- Pelvis

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    Full Text Available ... symptoms experienced by women such as: pelvic pain abnormal vaginal bleeding other menstrual problems Ultrasound exams also ... endometrial polyps fibroids cancer, especially in patients with abnormal uterine bleeding Some physicians also use 3-D ...

  7. Ultrasound -- Pelvis

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    Full Text Available ... The ultrasound exam room may have a television. Feel free to ask for your child's favorite channel. ... performed over an area of tenderness, you may feel pressure or minor pain from the transducer. Once ...

  8. Prostate Ultrasound

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    Full Text Available ... also known as benign prostatic hyperplasia (BPH) , with measurements acquired as needed for any treatment planning. detect ... areas of the body while other areas, especially air-filled lungs, are poorly suited for ultrasound. For ...

  9. Ultrasound -- Pelvis

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    Full Text Available ... ovarian cysts and uterine fibroids ovarian or uterine cancers A transvaginal ultrasound is usually performed to view ... detect: uterine anomalies uterine scars endometrial polyps fibroids cancer, especially in patients with abnormal uterine bleeding Some ...

  10. Prostate Ultrasound

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    Full Text Available ... rectum. top of page What are some common uses of the procedure? A transrectal ultrasound of the ... community, you can search the ACR-accredited facilities database . This website does not provide cost information. The ...

  11. Ultrasound -- Pelvis

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    Full Text Available ... kidneys. top of page What are some common uses of the procedure? In women, a pelvic ultrasound ... community, you can search the ACR-accredited facilities database . This website does not provide cost information. The ...

  12. Ultrasound -- Pelvis

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    Full Text Available ... of the reflected sound waves (called the Doppler effect). A computer collects and processes the sounds and ... standard diagnostic ultrasound , there are no known harmful effects on humans. top of page What are the ...

  13. Ultrasound -- Pelvis

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    Full Text Available ... sends out high-frequency sound waves (that the human ear cannot hear) into the body and then ... ultrasound , there are no known harmful effects on humans. top of page What are the limitations of ...

  14. Ultrasound -- Pelvis

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    Full Text Available ... various body organs such as the liver or kidneys. top of page What are some common uses ... women, a pelvic ultrasound exam can help identify: kidney stones bladder tumors other disorders of the urinary ...

  15. Prostate Ultrasound

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    Full Text Available ... echoes from the tissues in the body. The principles are similar to sonar used by boats and ... work? Ultrasound imaging is based on the same principles involved in the sonar used by bats, ships ...

  16. Ultrasound -- Pelvis

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    Full Text Available ... echoes from the tissues in the body. The principles are similar to sonar used by boats and ... work? Ultrasound imaging is based on the same principles involved in the sonar used by bats, ships ...

  17. Prostate Ultrasound

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    Full Text Available ... is at high risk for cancer. In this case, a biopsy is performed and an ultrasound probe ... will share the results with you. In some cases, the radiologist may discuss results with you at ...

  18. Ultrasound -- Pelvis

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    Full Text Available ... ovaries. Transvaginal ultrasound also evaluates the myometrium (muscular walls of the uterus). Sonohysterography allows for a more ... needle insertion) is usually minimal because the rectal wall is relatively insensitive to the pain in the ...

  19. Prostate Ultrasound

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    Full Text Available ... uses sound waves to produce pictures of a man’s prostate gland and to help diagnose symptoms such ... also called transrectal ultrasound, provides images of a man's prostate gland and surrounding tissue. The exam typically ...

  20. Ultrasound -- Pelvis

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    Full Text Available ... pain ambiguous genitalia and anomalies of pelvic organs early or delayed puberty in girls Pelvic ultrasound is ... sensitive to motion, and an active or crying child can prolong the examination process. To ensure a ...

  1. Ultrasound -- Pelvis

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    Full Text Available ... consist of a console containing a computer and electronics, a video display screen and a transducer that ... the preferred imaging modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound ...

  2. Ultrasound -- Pelvis

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    Full Text Available ... insertion. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... the transducer is pressed against the skin, it directs small pulses of inaudible, high-frequency sound waves ...

  3. Prostate Ultrasound

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    Full Text Available ... gel. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... the transducer is pressed against the skin, it directs small pulses of inaudible, high-frequency sound waves ...

  4. General Ultrasound Imaging

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    Full Text Available ... the patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... by a computer, which in turn creates a real-time picture on the monitor. One or more frames ...

  5. Remote just-in-time telementored trauma ultrasound: a double-factorial randomized controlled trial examining fluid detection and remote knobology control through an ultrasound graphic user interface display.

    Science.gov (United States)

    Kirkpatrick, Andrew W; McKee, Ian; McKee, Jessica L; Ma, Irene; McBeth, Paul B; Roberts, Derek J; Wurster, Charles L; Parfitt, Robbie; Ball, Chad G; Oberg, Scott; Sevcik, William; Hamilton, Douglas R

    2016-05-01

    Remote-telementored ultrasound involves novice examiners being remotely guided by experts using informatic-technologies. However, requiring a novice to perform ultrasound is a cognitively demanding task exacerbated by unfamiliarity with ultrasound-machine controls. We incorporated a randomized evaluation of using remote control of the ultrasound functionality (knobology) within a study in which the images generated by distant naive examiners were viewed on an ultrasound graphic user interface (GUI) display viewed on laptop computers by mentors in different cities. Fire-fighters in Edmonton (101) were remotely mentored from Calgary (n = 65), Nanaimo (n = 19), and Memphis (n = 17) to examine an ultrasound phantom randomized to contain free fluid or not. Remote mentors (2 surgeons, 1 internist, and 1 ED physician) were randomly assigned to use GUI knobology control during mentoring (GUIK+/GUIK-). Remote-telementored ultrasound was feasible in all cases. Overall accuracy for fluid detection was 97% (confidence interval = 91 to 99%) with 3 false negatives (FNs). Positive/negative likelihood ratios were infinity/0.0625. One FN occurred with the GUIK+ and 2 without (GUIK-). There were no statistical test performance differences in either group (GUIK+ and GUIK-). Ultrasound-naive 1st responders can be remotely mentored with high accuracy, although providing basic remote control of the knobology did not affect outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Experimental study of some homeostatic parameters at late times after exposure to radiation

    International Nuclear Information System (INIS)

    Chertkov, K.S.; Andrianova, I.E.; Atamanova, O.M.; Filimonova, G.I.; Nesterova, T.A.; Sbitneva, M.F.; Glushkov, V.A.; Chotij, V.G.; Stejmatskaya, Z.A.

    1994-01-01

    Following radiation damage from LD 50 - LD 97 , changes in blood, immune and endocrine parameters were revealed and followed up in dogs at the time of late effects development, 3-18 months after exposure. The changes result from post-radiation immunodeficiency and resemble those observed in residents of radioactive contaminate areas or in men participated in Chernobyl accident amelioration

  7. Changes in indinavir exposure over time : a case study in six HIV-1-infected children

    NARCIS (Netherlands)

    Fraaij, PLA; Bergshoeff, AS; van Rossum, AMC; Hartwig, NG; Burger, DM; de Groot, R

    2003-01-01

    Objective: To study changes in indinavir exposure over time in HIV-1-infected children. Materials and methods: Protease inhibitor (PI)-naive HIV-1-infected children were treated with indinavir, zidovudine and lamivudine. Steady-state plasma pharmacokinetic (PK) sampling was carried out as standard

  8. Early Adolescent Boys' Exposure to Internet Pornography: Relationships to Pubertal Timing, Sensation Seeking, and Academic Performance

    Science.gov (United States)

    Beyens, Ine; Vandenbosch, Laura; Eggermont, Steven

    2015-01-01

    Research has demonstrated that adolescents regularly use Internet pornography. This two-wave panel study aimed to test an integrative model in early adolescent boys (M[subscript age] = 14.10; N = 325) that (a) explains their exposure to Internet pornography by looking at relationships with pubertal timing and sensation seeking, and (b) explores…

  9. Early adolescent boys’ exposure to Internet pornography: relationships to pubertal timing, sensation seeking, and academic performance

    NARCIS (Netherlands)

    Beyens, I.; Vandenbosch, L.; Eggermont, S.

    2015-01-01

    Research has demonstrated that adolescents regularly use Internet pornography. This two-wave panel study aimed to test an integrative model in early adolescent boys (Mage = 14.10; N = 325) that (a) explains their exposure to Internet pornography by looking at relationships with pubertal timing and

  10. The molecular basis of simple relationships between exposure concentration and toxic effects with time.

    Science.gov (United States)

    Tennekes, Henk A; Sánchez-Bayo, Francisco

    2013-07-05

    Understanding the toxicity of chemicals to organisms requires considering the molecular mechanisms involved as well as the relationships between exposure concentration and toxic effects with time. Our current knowledge about such relationships is mainly explained from a toxicodynamic and toxicokinetic perspective. This paper re-introduces an old approach that takes into account the biochemical mode of action and their resulting biological effects over time of exposure. Empirical evidence demonstrates that the Druckrey-Küpfmüller toxicity model, which was validated for chemical carcinogens in the early 1960s, is also applicable to a wide range of toxic compounds in ecotoxicology. According to this model, the character of a poison is primarily determined by the reversibility of critical receptor binding. Chemicals showing irreversible or slowly reversible binding to specific receptors will produce cumulative effects with time of exposure, and whenever the effects are also irreversible (e.g. death) they are reinforced over time; these chemicals have time-cumulative toxicity. Compounds having non-specific receptor binding, or involving slowly reversible binding to some receptors that do not contribute to toxicity, may also be time-dependent; however, their effects depend primarily on the exposure concentration, with time playing a minor role. Consequently, the mechanism of toxic action has important implications for risk assessment. Traditional risk approaches cannot predict the impacts of toxicants with time-cumulative toxicity in the environment. New assessment procedures are needed to evaluate the risk that the latter chemicals pose on humans and the environment. An example is shown to explain how the risk of time-dependent toxicants is underestimated when using current risk assessment protocols. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  11. Physics of Ultrasound. Chapter 12

    Energy Technology Data Exchange (ETDEWEB)

    Lacefield, J. C. [University of Western Ontario, London (Canada)

    2014-09-15

    Ultrasound is the most commonly used diagnostic imaging modality, accounting for approximately 25% of all imaging examinations performed worldwide at the beginning of the 21st century. The success of ultrasound may be attributed to a number of attractive characteristics, including the relatively low cost and portability of an ultrasound scanner, the non-ionizing nature of ultrasound waves, the ability to produce real time images of blood flow and moving structures such as the beating heart, and the intrinsic contrast among soft tissue structures that is achieved without the need for an injected contrast agent. The latter characteristic enables ultrasound to be used for a wide range of medical applications, which historically have primarily included cardiac and vascular imaging, imaging of the abdominal organs and, most famously, in utero imaging of the developing fetus. Ongoing technological improvements continue to expand the use of ultrasound for many applications, including cancer imaging, musculoskeletal imaging, ophthalmology and others. The term ultrasound refers specifically to acoustic waves at frequencies greater than the maximum frequency audible to humans, which is nominally 20 kHz. Diagnostic imaging is generally performed using ultrasound in the frequency range of 2–15 MHz. The choice of frequency is dictated by a trade off between spatial resolution and penetration depth, since higher frequency waves can be focused more tightly but are attenuated more rapidly by tissue. The information contained in an ultrasonic image is influenced by the physical processes underlying propagation, reflection and attenuation of ultrasound waves in tissue.

  12. Fight and air exposure times of caught and released salmonids from the South Fork Snake River

    Science.gov (United States)

    Roth, Curtis J.; Schill, Daniel J.; Quist, Michael C.

    2018-01-01

    Catch-and-release regulations are among the most common types of fishing regulations. In recent years, concerns have arisen regarding the exposure of fish to air during catch-and-release angling. The purpose of our study was to quantify the length of time angled fish were exposed to air by anglers in a typical catch-and-release fishery and relate it to the lengths of time reported to produce negative effects. In total, 312 individual anglers were observed on the South Fork Snake River, Idaho, from May through August 2016. Fight time varied from 1.1 s to 230.0 s, and average fight time was 40.0 s (SD = 36.8). Total air exposure times varied from 0.0 s to 91.8 s and averaged 19.3 s (SD = 15.0). Though not statistically significant, a trend in reduced fight times was observed when anglers were guided and increased air exposure times when a net was used and a picture was taken. Results of the current study suggest that anglers expose fish to air for periods that are much less than those reported to cause mortality.

  13. Cranial Ultrasound/Head Ultrasound

    Science.gov (United States)

    ... used to screen for brain conditions associated with prematurity, such as bleeding or brain tissue damage as ... or crying child will slow the examination process. Large patients are more difficult to image by ultrasound, ...

  14. Temporal variation of optimal UV exposure time over Korea: risks and benefits of surface UV radiation

    Science.gov (United States)

    Lee, Y. G.; Koo, J. H.

    2015-12-01

    Solar UV radiation in a wavelength range between 280 to 400 nm has both positive and negative influences on human body. Surface UV radiation is the main natural source of vitamin D, providing the promotion of bone and musculoskeletal health and reducing the risk of a number of cancers and other medical conditions. However, overexposure to surface UV radiation is significantly related with the majority of skin cancer, in addition other negative health effects such as sunburn, skin aging, and some forms of eye cataracts. Therefore, it is important to estimate the optimal UV exposure time, representing a balance between reducing negative health effects and maximizing sufficient vitamin D production. Previous studies calculated erythemal UV and vitamin-D UV from the measured and modelled spectral irradiances, respectively, by weighting CIE Erythema and Vitamin D3 generation functions (Kazantzidis et al., 2009; Fioletov et al., 2010). In particular, McKenzie et al. (2009) suggested the algorithm to estimate vitamin-D production UV from erythemal UV (or UV index) and determined the optimum conditions of UV exposure based on skin type Ⅱ according to the Fitzpatrick (1988). Recently, there are various demands for risks and benefits of surface UV radiation on public health over Korea, thus it is necessary to estimate optimal UV exposure time suitable to skin type of East Asians. This study examined the relationship between erythemally weighted UV (UVEry) and vitamin D weighted UV (UVVitD) over Korea during 2004-2012. The temporal variations of the ratio (UVVitD/UVEry) were also analyzed and the ratio as a function of UV index was applied in estimating the optimal UV exposure time. In summer with high surface UV radiation, short exposure time leaded to sufficient vitamin D and erythema and vice versa in winter. Thus, the balancing time in winter was enough to maximize UV benefits and minimize UV risks.

  15. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... guide biopsy of breast cancer ( see the Ultrasound-Guided Breast Biopsy page . diagnose a variety of heart ... Articles and Media Angioplasty and Vascular Stenting Ultrasound-Guided Breast Biopsy Obstetric Ultrasound Ultrasound - Prostate Biopsies - Overview ...

  16. General Ultrasound Imaging

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    Full Text Available ... of an ultrasound examination. Doppler ultrasound , also called color Doppler ultrasonography, is a special ultrasound technique that ... kidneys. There are three types of Doppler ultrasound: Color Doppler uses a computer to convert Doppler measurements ...

  17. General Ultrasound Imaging

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    Full Text Available ... Index A-Z General Ultrasound Ultrasound imaging uses sound waves to produce pictures of the inside of ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  18. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... those sound waves to create an image. Ultrasound examinations do not use ionizing radiation (as used in ... ultrasound study may be part of an ultrasound examination. Doppler ultrasound , also called color Doppler ultrasonography, is ...

  19. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... What are the limitations of General Ultrasound Imaging? What is General Ultrasound Imaging? Ultrasound is safe and ... be heard with every heartbeat. top of page What are some common uses of the procedure? Ultrasound ...

  20. Comparison of a GPS needle-tracking system, multiplanar imaging and 2D imaging for real-time ultrasound-guided epidural anaesthesia: A randomized, comparative, observer-blinded study on phantoms.

    Science.gov (United States)

    Menacé, Cécilia; Choquet, Olivier; Abbal, Bertrand; Bringuier, Sophie; Capdevila, Xavier

    2017-04-01

    The real-time ultrasound-guided paramedian sagittal oblique approach for neuraxial blockade is technically demanding. Innovative technologies have been developed to improve nerve identification and the accuracy of needle placement. The aim of this study was to evaluate three types of ultrasound scans during ultrasound-guided epidural lumbar punctures in a spine phantom. Eleven sets of 20 ultrasound-guided epidural punctures were performed with 2D, GPS, and multiplanar ultrasound machines (660 punctures) on a spine phantom using an in-plane approach. For all punctures, execution time, number of attempts, bone contacts, and needle redirections were noted by an independent physician. Operator comfort and visibility of the needle (tip and shaft) were measured using a numerical scale. The use of GPS significantly decreased the number of punctures, needle repositionings, and bone contacts. Comfort of the physician was also significantly improved with the GPS system compared with the 2D and multiplanar systems. With the multiplanar system, the procedure was not facilitated and execution time was longer compared with 2D imaging after Bonferroni correction but interaction between the type of ultrasound system and mean execution time was not significant in a linear mixed model. There were no significant differences regarding needle tip and shaft visibility between the systems. Multiplanar and GPS needle-tracking systems do not reduce execution time compared with 2D imaging using a real-time ultrasound-guided paramedian sagittal oblique approach in spine phantoms. The GPS needle-tracking system can improve performance in terms of operator comfort, the number of attempts, needle redirections and bone contacts. Copyright © 2016 Société française d'anesthésie et de réanimation (Sfar). Published by Elsevier Masson SAS. All rights reserved.

  1. MRI-guided gas bubble enhanced ultrasound heating in in vivo rabbit thigh

    International Nuclear Information System (INIS)

    Sokka, S D; King, R; Hynynen, K

    2003-01-01

    In this study, we propose a focused ultrasound surgery protocol that induces and then uses gas bubbles at the focus to enhance the ultrasound absorption and ultimately create larger lesions in vivo. MRI and ultrasound visualization and monitoring methods for this heating method are also investigated. Larger lesions created with a carefully monitored single ultrasound exposure could greatly improve the speed of tumour coagulation with focused ultrasound. All experiments were performed under MRI (clinical, 1.5 T) guidance with one of two eight-sector, spherically curved piezoelectric transducers. The transducer, either a 1.1 or 1.7 MHz array, was driven by a multi-channel RF driving system. The transducer was mounted in an MRI-compatible manual positioning system and the rabbit was situated on top of the system. An ultrasound detector ring was fixed with the therapy transducer to monitor gas bubble activity during treatment. Focused ultrasound surgery exposures were delivered to the thighs of seven New Zealand white rabbits. The experimental, gas-bubble-enhanced heating exposures consisted of a high amplitude 300 acoustic watt, half second pulse followed by a 7 W, 14 W or 21 W continuous wave exposure for 19.5 s. The respective control sonications were 20 s exposures of 14 W, 21 W and 28 W. During the exposures, MR thermometry was obtained from the temperature dependency of the proton resonance frequency shift. MR T2-enhanced imaging was used to evaluate the resulting lesions. Specific metrics were used to evaluate the differences between the gas-bubble-enhanced exposures and their respective control sonications: temperatures with respect to time and space, lesion size and shape, and their agreement with thermal dose predictions. The bubble-enhanced exposures showed a faster temperature rise within the first 4 s and higher overall temperatures than the sonications without bubble formation. The spatial temperature maps and the thermal dose maps derived from the MRI

  2. Sonochemical synthesis, characterization, and effects of temperature, power ultrasound and reaction time on the morphological properties of two new nanostructured mercury(II) coordination supramolecule compounds.

    Science.gov (United States)

    Hayati, Payam; Rezvani, Ali Reza; Morsali, Ali; Molina, Daniel Ruiz; Geravand, Samira; Suarez-Garcia, Salvio; Villaecija, Miguel Angel Moreno; García-Granda, S; Mendoza-Meroño, Rafael; Retailleau, Pascal

    2017-07-01

    Two new mercury(II) coordination supramolecular compounds (CSCs) (1D and 0D), [Hg(L)(I) 2 ] n (1) and [Hg 2 (L') 2 (SCN) 2 ]·2H 2 O (2) (L=2-amino-4-methylpyridine and L'=2,6-pyridinedicarboxlic acid), have been synthesized under different experimental conditions. Micrometric crystals (bulk) or nano-sized materials have been obtained depending on using the branch tube method or sonochemical irradiation. All materials have been characterized by field emission scanning electron microscope (FESEM), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD) and FT-IR spectroscopy. Single crystal X-ray analyses on compounds 1 and 2 show that Hg 2+ ions are 4-coordinated and 5-coordinated, respectively. Topological analysis shows that the compound 1 and 2 have 2C1, sql net. The thermal stability of compounds 1 and 2 in bulk and nano-size has been studied by thermal gravimetric (TG), differential thermal analyses (DTA) for 1 and differential scanning calorimetry (DSC) for 2, respectively. Also, by changing counter ions were obtained various structures 1 and 2 (1D and 0D, respectively). The role of different parameters like power of ultrasound irradiation, reaction time and temperature on the growth and morphology of the nano-structures are studied. Results suggest that increasing power ultrasound irradiation and temperature together with reducing reaction time and concentration of initial reagents leads to a decrease in particle size. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Portable high-intensity focused ultrasound system with 3D electronic steering, real-time cavitation monitoring, and 3D image reconstruction algorithms: a preclinical study in pigs

    International Nuclear Information System (INIS)

    Choi, Jin Woo; Lee, Jae Young; Hwang, Eui Jin; Hwang, In Pyeong; Woo, Sung Min; Lee, Chang Joo; Park, Eun Joo; Choi, Byung Ihn

    2014-01-01

    The aim of this study was to evaluate the safety and accuracy of a new portable ultrasonography-guided high-intensity focused ultrasound (USg-HIFU) system with a 3-dimensional (3D) electronic steering transducer, a simultaneous ablation and imaging module, real-time cavitation monitoring, and 3D image reconstruction algorithms. To address the accuracy of the transducer, hydrophones in a water chamber were used to assess the generation of sonic fields. An animal study was also performed in five pigs by ablating in vivo thighs by single-point sonication (n=10) or volume sonication (n=10) and ex vivo kidneys by single-point sonication (n=10). Histological and statistical analyses were performed. In the hydrophone study, peak voltages were detected within 1.0 mm from the targets on the y- and z-axes and within 2.0-mm intervals along the x-axis (z-axis, direction of ultrasound propagation; y- and x-axes, perpendicular to the direction of ultrasound propagation). Twenty-nine of 30 HIFU sessions successfully created ablations at the target. The in vivo porcine thigh study showed only a small discrepancy (width, 0.5-1.1 mm; length, 3.0 mm) between the planning ultrasonograms and the pathological specimens. Inordinate thermal damage was not observed in the adjacent tissues or sonic pathways in the in vivo thigh and ex vivo kidney studies. Our study suggests that this new USg-HIFU system may be a safe and accurate technique for ablating soft tissues and encapsulated organs.

  4. Portable high-intensity focused ultrasound system with 3D electronic steering, real-time cavitation monitoring, and 3D image reconstruction algorithms: a preclinical study in pigs

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jin Woo; Lee, Jae Young; Hwang, Eui Jin; Hwang, In Pyeong; Woo, Sung Min; Lee, Chang Joo; Park, Eun Joo; Choi, Byung Ihn [Dept. of Radiology and Institute of Radiation Medicine, Seoul National University Hospital, Seoul (Korea, Republic of)

    2014-10-15

    The aim of this study was to evaluate the safety and accuracy of a new portable ultrasonography-guided high-intensity focused ultrasound (USg-HIFU) system with a 3-dimensional (3D) electronic steering transducer, a simultaneous ablation and imaging module, real-time cavitation monitoring, and 3D image reconstruction algorithms. To address the accuracy of the transducer, hydrophones in a water chamber were used to assess the generation of sonic fields. An animal study was also performed in five pigs by ablating in vivo thighs by single-point sonication (n=10) or volume sonication (n=10) and ex vivo kidneys by single-point sonication (n=10). Histological and statistical analyses were performed. In the hydrophone study, peak voltages were detected within 1.0 mm from the targets on the y- and z-axes and within 2.0-mm intervals along the x-axis (z-axis, direction of ultrasound propagation; y- and x-axes, perpendicular to the direction of ultrasound propagation). Twenty-nine of 30 HIFU sessions successfully created ablations at the target. The in vivo porcine thigh study showed only a small discrepancy (width, 0.5-1.1 mm; length, 3.0 mm) between the planning ultrasonograms and the pathological specimens. Inordinate thermal damage was not observed in the adjacent tissues or sonic pathways in the in vivo thigh and ex vivo kidney studies. Our study suggests that this new USg-HIFU system may be a safe and accurate technique for ablating soft tissues and encapsulated organs.

  5. Timing of first exposure to maternal depression and adolescent emotional disorder in a national Canadian cohort.

    Directory of Open Access Journals (Sweden)

    Kiyuri Naicker

    Full Text Available Correlations have been reported between behavioral and cognitive outcomes in adolescence and exposure to maternal depression during the first postpartum year, but the effects of timing of maternal depression during subsequent exposure periods have rarely been controlled for. This study aims to methodically investigate the importance of timing of initial exposure to maternal depression with respect to adolescent mental health outcomes.This study used data on 937 children from the National Longitudinal Study of Children and Youth (NLSCY, a nationally-representative longitudinal survey established in 1994 by Statistics Canada. Ordinal logistic regression was used to confirm associations between adolescent emotional disorder (at 12-13 years and initial exposure to maternal depression during 2-year intervals from birth to adolescence. Following their initial exposure to maternal depression, children were dropped from subsequent cycles. Stressful life events, chronic health conditions, maternal alcohol use, maternal marital status, gender, and SES were included as covariates.The results indicated that adolescents who were initially exposed to maternal depression between the ages of 2-3 years and 4-5 years had a two-fold increase in odds of emotional disorder. No increase in odds was observed in those initially exposed during the first postpartum year or later in childhood.The results demonstrate that a sensitive period of initial exposure to maternal depression may occur between the ages of 2 and 5, and not during the first year of life indicated by previous research. These findings are congruent with the literature on emotional and behavioral development in early childhood.

  6. Time series models of environmental exposures: Good predictions or good understanding.

    Science.gov (United States)

    Barnett, Adrian G; Stephen, Dimity; Huang, Cunrui; Wolkewitz, Martin

    2017-04-01

    Time series data are popular in environmental epidemiology as they make use of the natural experiment of how changes in exposure over time might impact on disease. Many published time series papers have used parameter-heavy models that fully explained the second order patterns in disease to give residuals that have no short-term autocorrelation or seasonality. This is often achieved by including predictors of past disease counts (autoregression) or seasonal splines with many degrees of freedom. These approaches give great residuals, but add little to our understanding of cause and effect. We argue that modelling approaches should rely more on good epidemiology and less on statistical tests. This includes thinking about causal pathways, making potential confounders explicit, fitting a limited number of models, and not over-fitting at the cost of under-estimating the true association between exposure and disease. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Therapeutic ultrasound

    International Nuclear Information System (INIS)

    Crum, Lawrence A

    2004-01-01

    The use of ultrasound in medicine is now quite commonplace, especially with the recent introduction of small, portable and relatively inexpensive, hand-held diagnostic imaging devices. Moreover, ultrasound has expanded beyond the imaging realm, with methods and applications extending to novel therapeutic and surgical uses. These applications broadly include: tissue ablation, acoustocautery, lipoplasty, site-specific and ultrasound mediated drug activity, extracorporeal lithotripsy, and the enhancement of natural physiological functions such as wound healing and tissue regeneration. A particularly attractive aspect of this technology is that diagnostic and therapeutic systems can be combined to produce totally non-invasive, imageguided therapy. This general lecture will review a number of these exciting new applications of ultrasound and address some of the basic scientific questions and future challenges in developing these methods and technologies for general use in our society. We shall particularly emphasize the use of High Intensity Focused Ultrasound (HIFU) in the treatment of benign and malignant tumors as well as the introduction of acoustic hemostasis, especially in organs which are difficult to treat using conventional medical and surgical techniques. (amum lecture)

  8. High precision instrumentation for measuring the true exposure time in diagnostic X-ray examinations

    International Nuclear Information System (INIS)

    Silva, Danubia B.; Santos, Marcus A.P.; Barros, Fabio R.; Santos, Luiz A.P.

    2013-01-01

    One of the most important physical quantities to be evaluated in diagnostic radiology is the radiation exposure time experimented by the patient during the X-ray examination. IAEA and WHO organizations have suggested that any country must create a quality surveillance program to verify if each type of ionizing radiation equipment used in the hospitals and medical clinics are in conformity with the accepted uncertainties following the international standards. The purpose of this work is to present a new high precision methodology for measuring true exposure time in diagnostic X-ray examinations: pulsed, continuous or digital one. An electronic system named CronoX, which will be soon registered at the Brazilian Patent Office (INPI), is the equipment that provides such a high precision measurement. The principle of measurement is based on the electrical signal captured by a sensor that enters in a regeneration amplifier to transform it in a digital signal, which is treated by a microprocessor (uP). The signal treatment results in a two measured times: 1) T rx , the true X-ray exposure time; 2) T nx , the time in which the X-ray machine is repeatedly cut off during the pulsed irradiation and there is no delivery dose to the patient. Conventional Polymat X-ray equipment and dental X-ray machines were used to generate X-ray photons and take the measurements with the electronic systems. The results show that such a high precision instrumentation displays the true exposure time in diagnostic X-ray examinations and indicates a new method to be purposed for the quality surveillance programs in radiology. (author)

  9. A Diagnostic Ultrasound Imaging System

    International Nuclear Information System (INIS)

    Lee, Seong Woo

    1999-01-01

    The ability to see the internal organs of the human body in a noninvasive way is a powerful diagnostic tool of modern medicine. Among these imaging modalities such as X-ray, MRI, and ultrasound. MRI and ultrasound are presenting much less risk of undesirable damage of both patient and examiner. In fact, no deleterious effects have been reported as a result of clinical examination by using MRI and ultrasound diagnostic equipment. As a result, their market volume has been rapidly increased. MRI has a good resolution. but there are a few disadvantages such as high price. non-real-time imaging capability. and expensive diagnostic cost. On the other hand, the ultrasound imaging system has inherently poor resolution as compared with X-ray and MRI. In spite of its poor resolution, the ultrasound diagnostic equipment is lower in price and has an ability of real-time imaging as compared with the others. As a result, the ultrasound imaging system has become general and essential modality for imaging the internal organs of human body. In this review various researches and developments to enhance the resolution of the ultrasound images are explained and future trends of the ultrasound imaging technology are described

  10. Time and frequency characteristics of temporary threshold shifts caused by pure tone exposures

    DEFF Research Database (Denmark)

    Ordoñez, Rodrigo Pizarro; Hammershøi, Dorte

    2011-01-01

    The time-frequency characteristics of Temporary Threshold Shifts (TTS) caused by pure tones were determined using the Békésy audiometric method with narrow-band noise of short duration as the probe stimuli. Two experiments were done using exposures of 3 min at 100 dB above threshold. In the first....... In the second experiment, the TTS recovery curve produced by a 1 kHz pure tone exposure was assessed at 1.5 kHz, at approximately 15 s intervals for the first 5 min and at regularly increasing intervals up to 45 min after the exposure. The results showed a maximum in the recovery around 2 min after the exposure....... The data gathered in these experiments were used to construct a mathematical model of TTS recovery. The model describes both the 1/2-octave shift and the 2 min bounce and it can be used in the comparison of temporary changes in auditory function, assessed at different times and frequencies....

  11. Modeling of ultrasound transducers

    DEFF Research Database (Denmark)

    Bæk, David

    This Ph.D. dissertation addresses ultrasound transducer modeling for medical ultrasound imaging and combines the modeling with the ultrasound simulation program Field II. The project firstly presents two new models for spatial impulse responses (SIR)s to a rectangular elevation focused transducer...... (REFT) and to a convex rectangular elevation focused transducer (CREFT). These models are solvable on an analog time scale and give exact smooth solutions to the Rayleigh integral. The REFT model exhibits a root mean square (RMS) error relative to Field II predictions of 0.41 % at 3400 MHz, and 1.......37 % at 100MHz. The CREFT model exhibits a RMS deviation of 0.01 % relative to the exact numerical solution on a CREFT transducer. A convex non-elevation focused, a REFT, and a linear flat transducer are shown to be covered with the CREFT model as well. Pressure pulses calculated with a one...

  12. In-situ real time measurements of net erosion rates of copper during hydrogen plasma exposure

    Science.gov (United States)

    Kesler, Leigh; Wright, Graham; Peterson, Ethan; Whyte, Dennis

    2013-10-01

    In order to properly understand the dynamics of net erosion/deposition in fusion reactors, such as tokamaks, a diagnostic measuring the real time rates of net erosion/deposition during plasma exposure is necessary. The DIONISOS experiment produces real time measurements of net erosion/deposition by using Rutherford backscattering spectroscopy (RBS) ion beam analysis simultaneously with plasma exposure from a helicon plasma source. This in-situ method improves on ex-situ weight loss measurements by allowing measurement of possible synergistic effects of high ion implantation rates and net erosion rate and by giving a real time response to changes in plasma parameters. Previous work has validated this new technique for measuring copper (Cu) erosion from helium (He) plasma ion bombardment. This technique is now extended to measure copper erosion due to deuterium and hydrogen plasma ion exposure. Targets used were a 1.5 μm Cu layer on an aluminum substrate. Cu layer thickness is tracked in real time using 1.2 MeV proton RBS. Measured erosion rates will be compared to results from literature and He erosion rates. Supported by US DoE award DE-SC00-02060.

  13. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... the amplitude (loudness), frequency (pitch) and time it takes for the ultrasound signal to return from the area within the patient that is being examined to the transducer (the device placed on the patient's skin to send and ...

  14. A 1 MHz BW 34.2 fJ/step Continuous Time Delta Sigma Modulator With an Integrated Mixer for Cardiac Ultrasound.

    Science.gov (United States)

    Kaald, Rune; Eggen, Trym; Ytterdal, Trond

    2017-02-01

    Fully digitized 2D ultrasound transducer arrays require one ADC per channel with a beamforming architecture consuming low power. We give design considerations for per-channel digitization and beamforming, and present the design and measurements of a continuous time delta-sigma modulator (CTDSM) for cardiac ultrasound applications. By integrating a mixer into the modulator frontend, the phase and frequency of the input signal can be shifted, thereby enabling both improved conversion efficiency and narrowband beamforming. To minimize the power consumption, we propose an optimization methodology using a simulated annealing framework combined with a C++ simulator solving linear electrical networks. The 3rd order single-bit feedback type modulator, implemented in a 65 nm CMOS process, achieves an SNR/SNDR of 67.8/67.4 dB across 1 MHz bandwidth consuming 131 [Formula: see text] of power. The achieved figure of merit of 34.2 fJ/step is comparable with state-of-the-art feedforward type multi-bit designs. We further demonstrate the influence to the dynamic range when performing dynamic receive beamforming on recorded delta-sigma modulated bit-stream sequences.

  15. Timing and Duration of Drug Exposure Affects Outcomes of a Drug-Nutrient Interaction During Ontogeny

    Directory of Open Access Journals (Sweden)

    Jane Alcorn

    2010-10-01

    Full Text Available Significant drug-nutrient interactions are possible when drugs and nutrients share the same absorption and disposition mechanisms. During postnatal development, the outcomes of drug-nutrient interactions may change with postnatal age since these processes undergo ontogenesis through the postnatal period. Our study investigated the dependence of a significant drug-nutrient interaction (cefepime-carnitine on the timing and duration of drug exposure relative to postnatal age. Rat pups were administered cefepime (5 mg/kg twice daily subcutaneously according to different dosing schedules (postnatal day 1-4, 1-8, 8-11, 8-20, or 1-20. Cefepime significantly reduced serum and heart L-carnitine levels in postnatal day 1-4, 1-8 and 8-11 groups and caused severe degenerative changes in ventricular myocardium in these groups. Cefepime also altered the ontogeny of several key L-carnitine homeostasis pathways. The qualitative and quantitative changes in levels of hepatic γ-butyrobetaine hydroxylase mRNA and activity, hepatic trimethyllysine hydroxlase mRNA, intestinal organic cation/carnitine transporter (Octn mRNA, and renal Octn2 mRNA depended on when during postnatal development the cefepime exposure occurred and duration of exposure. Despite lower levels of heart L-carnitine in earlier postnatal groups, levels of carnitine palmitoyltransferase mRNA and activity, heart Octn2 mRNA and ATP levels in all treatment groups remained unchanged with cefepime exposure. However, changes in other high energy phosphate substrates were noted and reductions in the phosphocreatine/ATP ratio were found in rat pups with normal serum L-carnitine levels. In summary, our data suggest a significant drug-nutrient transport interaction in developing neonates, the nature of which depends on the timing and duration of exposure relative to postnatal age.

  16. Real-time measurement of outdoor worker's exposure to solar ultraviolet radiation in Pretoria, South Africa

    Directory of Open Access Journals (Sweden)

    Mmathapelo Makgabutlane

    2015-05-01

    Full Text Available The city of Pretoria in South Africa receives considerable solar ultraviolet radiation (UVR because of its low latitude (22–35°S and relatively clear skies. Certain meteorological factors affect the amount of solar UVR that reaches the ground; the most dominant factors being stratospheric ozone, cloud cover and solar zenith angle. It is known that overexposure to solar UVR may lead to the development of adverse health conditions, the most significant being skin cancer. Outdoor workers spend a significant amount of time outside and are thus susceptible to this risk. In this case study, we estimated, for the first time, the real-time solar UVR exposure of an outdoor worker in Pretoria. Measurements were made on 27 and 28 May 2013 using a handheld ultraviolet index (UVI meter calibrated against a science-grade biometer at the South African Weather Service in Pretoria. Personal exposure estimation was used to discern the pattern in diurnal and annual sunburn risk for the outdoor worker. Ambient UVR levels ranged from 0 UVI to 4.66 UVI and the outdoor worker’s potential exposure estimates regularly exceeded 80% of these levels depending on the time of day. The risk of sunburn was evident; however, actual incidents would depend on individual skin photosensitivity and melanin content, as well as sun protection used. Further research is needed to determine the personal exposure estimations of outdoor workers in other provinces in which solar UVR levels may be equally high, or higher than those in Pretoria.

  17. Research interface on a programmable ultrasound scanner.

    Science.gov (United States)

    Shamdasani, Vijay; Bae, Unmin; Sikdar, Siddhartha; Yoo, Yang Mo; Karadayi, Kerem; Managuli, Ravi; Kim, Yongmin

    2008-07-01

    Commercial ultrasound machines in the past did not provide the ultrasound researchers access to raw ultrasound data. Lack of this ability has impeded evaluation and clinical testing of novel ultrasound algorithms and applications. Recently, we developed a flexible ultrasound back-end where all the processing for the conventional ultrasound modes, such as B, M, color flow and spectral Doppler, was performed in software. The back-end has been incorporated into a commercial ultrasound machine, the Hitachi HiVision 5500. The goal of this work is to develop an ultrasound research interface on the back-end for acquiring raw ultrasound data from the machine. The research interface has been designed as a software module on the ultrasound back-end. To increase the amount of raw ultrasound data that can be spooled in the limited memory available on the back-end, we have developed a method that can losslessly compress the ultrasound data in real time. The raw ultrasound data could be obtained in any conventional ultrasound mode, including duplex and triplex modes. Furthermore, use of the research interface does not decrease the frame rate or otherwise affect the clinical usability of the machine. The lossless compression of the ultrasound data in real time can increase the amount of data spooled by approximately 2.3 times, thus allowing more than 6s of raw ultrasound data to be acquired in all the modes. The interface has been used not only for early testing of new ideas with in vitro data from phantoms, but also for acquiring in vivo data for fine-tuning ultrasound applications and conducting clinical studies. We present several examples of how newer ultrasound applications, such as elastography, vibration imaging and 3D imaging, have benefited from this research interface. Since the research interface is entirely implemented in software, it can be deployed on existing HiVision 5500 ultrasound machines and may be easily upgraded in the future. The developed research

  18. Comparative studies on permanent prostate brachytherapy: pre-plan and real-time transrectal ultrasound guided iodine-125 seed implants at Korle-Bu Teaching Hospital, Ghana

    International Nuclear Information System (INIS)

    Kalolo, L.T.

    2013-06-01

    This research was carried out to investigate and compare the real-time and pre-plan implant at the Radiotherapy Department of the Korle Bu Teaching Hospital, Ghana. Prowess Panther 4.5 treatment planning system and variseed 7.2 software were used for pre-plan and real-time implant respectively. The study was conducted for eighty three (83) patients treated for prostate cancer through real-time implant brachytherapy between september, 2008 to April, 2013. Thirty one patients (31) patients whose ultrasound images were available were selected for the pre-plan study. The slices of ultrasound images were re-drawn on transparent A-4 sheets and later on scanned, contoured and registered in the treatment planning system (prowess 4.5). After planning, the volume to be implanted, total number of needles, seeds and the total activity of the source were displayed. Comparison was done withe the pre-plan and real-time implant. In both cases the variation was below 5% as recommended in dosimetry. About 30% - 40% of the imported seeds were left un-used due to over-estimation of seeds ordered from the manufacturer (BARD Company-USA). Hence this work (pre-plan) aims to solve this problem. The comparison for dosimetric parameters was assessed for prostate, urethra and rectum as (V 95%, V 100%, V 150%, D90Gy, D90%), (D90Gy, D90%, D30Gy, D30% ) and (V 100%, D30Gy and D30%) respectively and the variation were within the limit of ± 5%. Comparison of dosimetric values for this work were done with other institutions, like Karolinska university hospital, Sweden, The institute of Curie/ hospital Cochin Group Paris-France and European recommendations. The values reported at Korle - Bu teaching hospital (this work) were in good agreement with the international guidelines. (au)

  19. Prospects for quantitative and time-resolved double and continuous exposure off-axis electron holography

    Energy Technology Data Exchange (ETDEWEB)

    Migunov, Vadim, E-mail: v.migunov@fz-juelich.de [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Dwyer, Christian [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Department of Physics, Arizona State University, Tempe, AZ 85287 (United States); Boothroyd, Chris B. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Pozzi, Giulio [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Department of Physics and Astronomy, University of Bologna, viale B. Pichat 6/2, Bologna 40127 (Italy); Dunin-Borkowski, Rafal E. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany)

    2017-07-15

    The technique of double exposure electron holography, which is based on the superposition of two off-axis electron holograms, was originally introduced before the availability of digital image processing to allow differences between electron-optical phases encoded in two electron holograms to be visualised directly without the need for holographic reconstruction. Here, we review the original method and show how it can now be extended to permit quantitative studies of phase shifts that oscillate in time. We begin with a description of the theory of off-axis electron hologram formation for a time-dependent electron wave that results from the excitation of a specimen using an external stimulus with a square, sinusoidal, triangular or other temporal dependence. We refer to the more general method as continuous exposure electron holography, present preliminary experimental measurements and discuss how the technique can be used to image electrostatic potentials and magnetic fields during high frequency switching experiments. - Highlights: • Double and continuous exposure electron holography are described in detail. • The ability to perform quantitative studies of phase shifts that are oscillating in time is illustrated. • Theoretical considerations related to noise are presented. • Future high frequency electromagnetic switching experiments are proposed.

  20. Real-time measurement of dust in the workplace using video exposure monitoring: Farming to pharmaceuticals

    International Nuclear Information System (INIS)

    Walsh, P T; Forth, A R; Clark, R D R; Dowker, K P; Thorpe, A

    2009-01-01

    Real-time, photometric, portable dust monitors have been employed for video exposure monitoring (VEM) to measure and highlight dust levels generated by work activities, illustrate dust control techniques, and demonstrate good practice. Two workplaces, presenting different challenges for measurement, were used to illustrate the capabilities of VEM: (a) poultry farming activities and (b) powder transfer operations in a pharmaceutical company. For the poultry farm work, the real-time monitors were calibrated with respect to the respirable and inhalable dust concentrations using cyclone and IOM reference samplers respectively. Different rankings of exposure for typical activities were found on the small farm studied here compared to previous exposure measurements at larger poultry farms: these were mainly attributed to the different scales of operation. Large variations in the ratios of respirable, inhalable and real-time monitor TWA concentrations of poultry farm dust for various activities were found. This has implications for the calibration of light-scattering dust monitors with respect to inhalable dust concentration. In the pharmaceutical application, the effectiveness of a curtain barrier for dust control when dispensing powder in a downflow booth was rapidly demonstrated.