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1

Combined PET/MRI Scanner.  

National Technical Information Service (NTIS)

A combined PET/MRI scanner generally includes a magnet for producing a magnetic field suitable for magnetic resonance imaging, a radiofrequency (RF) coil disposed within the magnetic field produced by the magnet and a ring tomograph disposed within the ma...

C. L. Woody, D. J. Schlyer, J. F. Pratte, P. Vaska, S. Stoll, W. D. Rooney

2004-01-01

2

An RF dosimeter for independent SAR measurement in MRI scanners  

SciTech Connect

Purpose: The monitoring and management of radio frequency (RF) exposure is critical for ensuring magnetic resonance imaging (MRI) safety. Commercial MRI scanners can overestimate specific absorption rates (SAR) and improperly restrict clinical MRI scans or the application of new MRI sequences, while underestimation of SAR can lead to tissue heating and thermal injury. Accurate scanner-independent RF dosimetry is essential for measuring actual exposure when SAR is critical for ensuring regulatory compliance and MRI safety, for establishing RF exposure while evaluating interventional leads and devices, and for routine MRI quality assessment by medical physicists. However, at present there are no scanner-independent SAR dosimeters. Methods: An SAR dosimeter with an RF transducer comprises two orthogonal, rectangular copper loops and a spherical MRI phantom. The transducer is placed in the magnet bore and calibrated to approximate the resistive loading of the scanner's whole-body birdcage RF coil for human subjects in Philips, GE and Siemens 3 tesla (3T) MRI scanners. The transducer loop reactances are adjusted to minimize interference with the transmit RF field (B{sub 1}) at the MRI frequency. Power from the RF transducer is sampled with a high dynamic range power monitor and recorded on a computer. The deposited power is calibrated and tested on eight different MRI scanners. Whole-body absorbed power vs weight and body mass index (BMI) is measured directly on 26 subjects. Results: A single linear calibration curve sufficed for RF dosimetry at 127.8 MHz on three different Philips and three GE 3T MRI scanners. An RF dosimeter operating at 123.2 MHz on two Siemens 3T scanners required a separate transducer and a slightly different calibration curve. Measurement accuracy was ?3%. With the torso landmarked at the xiphoid, human adult whole?body absorbed power varied approximately linearly with patient weight and BMI. This indicates that whole-body torso SAR is on average independent of the imaging subject, albeit with fluctuations. Conclusions: Our 3T RF dosimeter and transducers accurately measure RF exposure in body-equivalent loads and provide scanner-independent assessments of whole-body RF power deposition for establishing safety compliance useful for MRI sequence and device testing.

Qian, Di; Bottomley, Paul A. [Division of MR Research, Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287 and Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States)] [Division of MR Research, Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287 and Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); El-Sharkawy, AbdEl-Monem M.; Edelstein, William A., E-mail: w.edelstein@gmail.com [Division of MR Research, Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287 (United States)

2013-12-15

3

Repeated fMRI Using Iron Oxide Contrast Agent in Awake, Behaving Macaques at 3 Tesla  

Microsoft Academic Search

Iron oxide contrast agents have been employed extensively in anesthetized rodents to enhance fMRI sensitivity and to study the physiology of cerebral blood volume (CBV) in relation to blood oxygen level-dependent (BOLD) signal following neuronal activation. This study quantified the advantages of exogenous agent for repeated neuroimaging in awake, nonhuman primates using a clinical 3 Tesla scanner. A monocrystalline iron

Francisca P. Leite; Doris Tsao; Wim Vanduffel; Denis Fize; Yuka Sasaki; Larry L. Wald; Anders M. Dale; Ken K. Kwong; Guy A. Orban; Bruce R. Rosen; Roger B. H. Tootell; Joseph B. Mandeville

2002-01-01

4

BRIEF COMMUNICATION A 7 Tesla fMRI Study of Amygdala Responses to Fearful Faces  

E-print Network

BRIEF COMMUNICATION A 7 Tesla fMRI Study of Amygdala Responses to Fearful Faces Wietske van der field strength. In this study, the feasibility of fMRI in the amygdalae at 7 Tesla was investigated in a fearful face depends on stimulus duration. Keywords Amygdala Á fMRI Á 7 Tesla Á Fear Á Face perception

Hadjikhani, Nouchine

5

3 Tesla intraoperative MRI for brain tumor surgery.  

PubMed

Implementation of intraoperative magnetic resonance imaging (iMRI) has been shown to optimize the extent of resection and safety of brain tumor surgery. In addition, iMRI can help account for the phenomenon of brain shift and can help to detect complications earlier than routine postoperative imaging, which can potentially improve patient outcome. The higher signal-to-noise ratio offered by 3 Tesla (T) iMRI compared with lower field strength systems is particularly advantageous. The purpose of this article is to review the imaging protocols, imaging findings, and technical considerations related to 3T iMRI. To maximize efficiency, iMRI sequences can be tailored to particular types of tumors and procedures, including nonenhancing brain tumor surgery, enhancing brain tumor surgery, transsphenoidal pituitary tumor surgery, and laser ablation. Unique imaging findings on iMRI include the presence of surgically induced enhancement, which can be a potential confounder for residual enhancing tumor, and hyperacute hemorrhage, which tends to have intermediate signal on T1-weighted sequences and high signal on T2-weighted sequences due to the presence of oxyhemoglobin. MR compatibility and radiofrequency shielding pose particularly stringent technical constraints at 3T and influence the design and usage of the surgical suite with iMRI. PMID:24921066

Ginat, Daniel Thomas; Swearingen, Brooke; Curry, William; Cahill, Daniel; Madsen, Joseph; Schaefer, Pamela W

2014-06-01

6

Observation of post-MCAO cortical inflammatory edema in rats by 7.0 Tesla MRI.  

PubMed

This study aimed to investigate inflammatory edema after cerebral ischemia through 7.0T MRI and proton magnetic resonance spectroscopy (MRS). All SD rats were randomly divided into sham operated group and middle cerebral artery occlusion (MCAO)-1 day, -3 day and -7 day groups. MRI scan of the brain was performed on a 7.0 Tesla MRI scanner. The volume of positive signals in the ischemic side was detected by using a T2 weighted spinecho multislice sequence; the changes in the height of water-peak were measured with point resolved spectroscopy (PRESS) sequences; cortical edema was detected by using wet-dry weight method; the degrees of nerve injury were evaluated by Bederson neurological score system; double-labeling immunofluorescence technique was used to explore the molecular mechanisms of post-ischemia cerebral edema. The results showed that high T2WI signals were observed in MCAO-1 day, -3 day and -7 day groups, and the water-peak height and water-peak area of MCAO groups were higher than those of sham operated group (P<0.05). Neurological score results were consistent with the degree of brain edema, and a large number of microglia accumulated in the ischemic cortex. Our results suggested that non-invasive MRI technology with the advantage of high spatial resolution and tissue resolution can comprehensively and dynamically observe inflammatory edema after cerebral ischemia from a three-dimensional space, and contribute to evaluation and treatments in clinic. PMID:24496690

Xiong, Ying; Zhu, Wen-zhen; Zhang, Qiang; Wang, Wei

2014-02-01

7

Speech Perception in MRI Scanner Noise by Persons with Aphasia  

ERIC Educational Resources Information Center

Purpose: To examine reductions in performance on auditory tasks by aphasic and neurologically intact individuals as a result of concomitant magnetic resonance imaging (MRI) scanner noise. Method: Four tasks together forming a continuum of linguistic complexity were developed. They included complex-tone pitch discrimination, same-different

Healy, Eric W.; Moser, Dana C.; Morrow-Odom, K. Leigh; Hall, Deborah A.; Fridriksson, Julius

2007-01-01

8

Magnetic Field Interactions of Orthodontic Wires during Magnetic Resonance Imaging (MRI) at 1.5 Tesla  

Microsoft Academic Search

Background: Orthodontic appliances pose a potential risk during magnetic resonance imaging (MRI) due to forces on metallic objects within the static magnetic field of MRI systems. The aim of the present investigation was to measure forces on orthodontic wires caused by the static magnetic field of a 1.5-Tesla MRI system, and to assess the safety hazards associated with these forces.

Dirk Schulze; Gerhard Adam; Brbel Kahl-Nieke

2005-01-01

9

Imaging Findings of Brain Death on 3-Tesla MRI  

PubMed Central

Objective To demonstrate the usefulness of 3-tesla (3T) magnetic resonance imaging (MRI) including T2-weighted imaging (T2WI), diffusion weighted imaging (DWI), time-of-flight (TOF) magnetic resonance angiography (MRA), T2*-weighted gradient recalled echo (GRE), and susceptibility weighted imaging (SWI) in diagnosing brain death. Materials and Methods Magnetic resonance imaging findings for 10 patients with clinically verified brain death (group I) and seven patients with comatose or stuporous mentality who did not meet the clinical criteria of brain death (group II) were retrospectively reviewed. Results Tonsilar herniation and loss of intraarterial flow signal voids (LIFSV) on T2WI were highly sensitive and specific findings for the diagnosis of brain death (p < 0.001 and < 0.001, respectively). DWI, TOF-MRA, and GRE findings were statistically different between the two groups (p = 0.015, 0.029, and 0.003, respectively). However, cortical high signal intensities in T2WI and SWI findings were not statistically different between the two group (p = 0.412 and 1.0, respectively). Conclusion T2-weighted imaging, DWI, and MRA using 3T MRI may be useful for diagnosing brain death. However, SWI findings are not specific due to high false positive findings. PMID:22977320

Sohn, Chul-Ho; Lee, Hwa-Pyung; Park, Jun Beom; Kim, Ealmaan; Kim, Eunhee; Park, Ui Jun; Kim, Hyoung-Tae; Ku, Jeonghun

2012-01-01

10

fMRI Scanner Noise Interaction with Affective Neural Processes  

PubMed Central

The purpose of the present study was the investigation of interaction effects between functional MRI scanner noise and affective neural processes. Stimuli comprised of psychoacoustically balanced musical pieces, expressing three different emotions (fear, neutral, joy). Participants (N=34, 19 female) were split into two groups, one subjected to continuous scanning and another subjected to sparse temporal scanning that features decreased scanner noise. Tests for interaction effects between scanning group (sparse/quieter vs continuous/noisier) and emotion (fear, neutral, joy) were performed. Results revealed interactions between the affective expression of stimuli and scanning group localized in bilateral auditory cortex, insula and visual cortex (calcarine sulcus). Post-hoc comparisons revealed that during sparse scanning, but not during continuous scanning, BOLD signals were significantly stronger for joy than for fear, as well as stronger for fear than for neutral in bilateral auditory cortex. During continuous scanning, but not during sparse scanning, BOLD signals were significantly stronger for joy than for neutral in the left auditory cortex and for joy than for fear in the calcarine sulcus. To the authors' knowledge, this is the first study to show a statistical interaction effect between scanner noise and affective processes and extends evidence suggesting scanner noise to be an important factor in functional MRI research that can affect and distort affective brain processes. PMID:24260420

Skouras, Stavros; Gray, Marcus; Critchley, Hugo; Koelsch, Stefan

2013-01-01

11

The role of 1.5 tesla MRI and anesthetic regimen concerning cardiac analysis in mice with cardiomyopathy.  

PubMed

Accurate assessment of left ventricular function in rodent models is essential for the evaluation of new therapeutic approaches for cardiac diseases. In our study, we provide new insights regarding the role of a 1.5 Tesla (T) magnetic resonance imaging (MRI) device and different anesthetic regimens on data validity. As dedicated small animal MRI and echocardiographic devices are not broadly available, we evaluated whether monitoring cardiac function in small rodents with a clinical 1.5 T MRI device is feasible. On a clinical electrocardiogram (ECG) synchronized 1.5 T MRI scanner we therefore studied cardiac function parameters of mice with chronic virus-induced cardiomyopathy. Thus, reduced left ventricular ejection fraction (LVEF) could be verified compared to healthy controls. However, our results showed a high variability. First, anesthesia with medetomidine, midazolam and fentanyl (MMF) led to depressed cardiac function parameters and more variability than isoflurane gas inhalation anesthesia, especially at high concentrations. Furthermore, calculation of an average ejection fraction value from sequenced scans significantly reduced the variance of the results. To sum up, we introduce the clinical 1.5 T MRI device as a new tool for effective analysis of left ventricular function in mice with cardiomyopathy. Besides, we suggest isoflurane gas inhalation anesthesia at high concentrations for variance reduction and recommend calculation of an average ejection fraction value from multiple sequenced MRI scans to provide valid data and a solid basis for further clinical testing. PMID:24747816

Grabmaier, Ulrich; Theiss, Hans D; Keithahn, Alexandra; Kreiner, Julia; Brenner, Christoph; Huber, Bruno; von der Helm, Christine; Gross, Lisa; Klingel, Karin; Franz, Wolfgang-M; Brunner, Stefan

2014-01-01

12

Absolute Temperature Monitoring Using RF Radiometry in the MRI Scanner  

PubMed Central

Temperature detection using microwave radiometry has proven value for noninvasively measuring the absolute temperature of tissues inside the body. However, current clinical radiometers operate in the gigahertz range, which limits their depth of penetration. We have designed and built a noninvasive radiometer which operates at radio frequencies (64 MHz) with ?100-kHz bandwidth, using an external RF loop coil as a thermal detector. The core of the radiometer is an accurate impedance measurement and automatic matching circuit of 0.05 ? accuracy to compensate for any load variations. The radiometer permits temperature measurements with accuracy of 0.1K, over a tested physiological range of 28 C40 C in saline phantoms whose electric properties match those of tissue. Because 1.5 T magnetic resonance imaging (MRI) scanners also operate at 64 MHz, we demonstrate the feasibility of integrating our radiometer with an MRI scanner to monitor RF power deposition and temperature dosimetry, obtaining coarse, spatially resolved, absolute thermal maps in the physiological range. We conclude that RF radiometry offers promise as a direct, noninvasive method of monitoring tissue heating during MRI studies and thereby providing an independent means of verifying patient-safe operation. Other potential applications include titration of hyper- and hypo-therapies. PMID:18026562

El-Sharkawy, AbdEl-Monem M.; Sotiriadis, Paul P.; Bottomley, Paul A.; Atalar, Ergin

2007-01-01

13

MAPPING HUMAN BRAIN FUNCTION WITH MRI AT 7 TESLA Xiaoping HU, Essa YACOUB, Josef PFEUFFER, Amir SCHUMEL,  

E-print Network

MAPPING HUMAN BRAIN FUNCTION WITH MRI AT 7 TESLA Xiaoping HU, Essa YACOUB, Josef PFEUFFER, Amir of the BOLD response to neural activity increase with the field strength. With the establishment of a 7 Tesla at a magnetic field strength that significantly exceeds 4 Tesla. Functional mapping using echo-planar imaging

14

Improved assessment of ex vivo brainstem neuroanatomy with high-resolution MRI and DTI at 7 Tesla.  

PubMed

The aim of the present work was to provide the topography of the main gray nuclei and white matter tracts of the human brainstem at 7 Tesla (7 T) high-field magnetic resonance imaging (MRI) using structural imaging (T1) and diffusion tensor imaging (DTI). Both imaging techniques represent a new field of increasing interest for its potential neuroanatomic and neuropathologic value. Brainstems were obtained postmortem from human donors, fixated by intracarotid perfusion of 10% neutral buffered formalin, and scanned in a Bruker BioSpec 7 T horizontal scanner. 3D-data sets were acquired using the modified driven equilibrium Fourier transform (MDEFT) sequence and Spin Echo-DTI (SE-DTI) sequence was used for DTI acquisition. High-resolution structural MRI and DTI of the human brainstem acquired postmortem reveals its basic cyto- and myeloar-chitectonic organization, only visualized to this moment by histological techniques and higher magnetic field strengths. Brainstem structures that are usually not observed with lower magnetic fields were now topographically identified at midbrain, pons, and medullar levels. The application of high-resolution structural MRI will contribute to precisely determine the extension and topography of brain lesions. Indeed, the current findings will be useful to interpret future high-resolution in vivo MRI studies in living humans. PMID:21542138

Soria, Guadalupe; De Notaris, Matteo; Tudela, Ral; Blasco, Gerard; Puig, Josep; Planas, Anna M; Pedraza, Salvador; Prats-Galino, Alberto

2011-06-01

15

A complete digital magnetic resonance imaging (MRI) system at low magnetic field (0.1 Tesla)  

Microsoft Academic Search

A new complete digital MRI system is developed to enhance the signal-to-noise ratio of the detected nuclear magnetic resonance (NMR) signals at low magnetic field (0.1 Tesla). The system is based on digital signal processor (DSP) that functions also as a controller and as an interface between the frequency translator and the digital synthesiser. The final system should be \\

Kosai RAOOF; A. Asfour; J. M. Fournier

2002-01-01

16

Evaluation of pressure-driven brain infusions in non-human primates by intra-operative 7 Tesla MRI  

PubMed Central

PURPOSE The goal of this study was to characterize the effects of pressure-driven brain infusions using high field intra-operative MRI. Understanding these effects is critical for upcoming neurodegeneration and oncology trials using convection-enhanced delivery (CED) to achieve large drug distributions with minimal off-target exposure. MATERIALS AND METHODS High-resolution T2-weighted and diffusion-tensor images were acquired serially on a 7 Tesla MRI scanner during six CED infusions in non-human primates. The images were used to evaluate the size, distribution, diffusivity and temporal dynamics of the infusions. RESULTS The infusion distribution had high contrast in the T2-weighted images. Diffusion tensor images showed the infusion increased diffusivity, reduced tortuosity and reduced anisotropy. These results suggested CED caused an increase in the extracellular space. CONCLUSIONS High-field intra-operative MRI can be used to monitor the distribution of infusate and changes in the geometry of the brains porous matrix. These techniques could be used to optimize the effectiveness of pressure-driven drug delivery to the brain. PMID:22887937

Rosenbluth, Kathryn H.; Martin, Alastair J.; Bringas, John; Bankiewicz, Krystof S.

2012-01-01

17

Clinical and technical considerations for high quality breast MRI at 3 Tesla.  

PubMed

The use of breast MRI at 3 tesla (T) has increased in use substantially in recent years. Potential benefits of moving to higher field strength MRI include improved morphologic and kinetic assessment of breast lesions through higher spatial and temporal resolution dynamic contrast-enhanced MR examinations. Furthermore, higher field strength holds promise for the development of superior advanced breast MRI techniques, such as diffusion weighted imaging and MR spectroscopy. To fully realize the benefits of moving to 3T, a thorough understanding of the technical and safety challenges of higher field strength imaging specific to breast MRI is paramount. Through the use of advanced coil technology, parallel imaging, dual-source parallel radiofrequency excitation, and image-based shimming techniques, many of these limiting technical factors can be overcome to achieve high quality breast MRI at 3T. PMID:23526757

Rahbar, Habib; Partridge, Savannah C; DeMartini, Wendy B; Thursten, Bonnie; Lehman, Constance D

2013-04-01

18

Acute Posterior Ischemic Optic Neuropathy Mimicking Posterior Cerebral Artery Stroke Visualized by 3-Tesla MRI  

PubMed Central

Acute ischemic lesions of the posterior optic nerve and optic tract can produce a variety of visual field defects. A 71-year-old woman presented with acute hemianopia, which led to rt-PA thrombolysis for suspected posterior cerebral artery ischemia. 3-Tesla cMRI, however, revealed the cause to be an acute posterior ischemic optic neuropathy. Cases like this may be more common than thought and quite regularly overlooked in clinical practice, especially when there is no high-resolution MRI available. This case strengthens the importance of repeat MR imaging in patients with persistent visual field defects. PMID:23185170

Menzel, Tilman; Kern, Rolf; Griebe, Martin; Hennerici, Michael; Fatar, Marc

2012-01-01

19

Design and development of a respiratory monitoring device to be used in conjuction with MRI scanners  

Microsoft Academic Search

The aim of this project was to design and manufacture a respiratory monitoring device that operates in conjunction with MRI scanners to produce higher quality images. The resultant quality of many MRI images depends on how well the patient can control their breathing activity. This research has been successful in designing and manufacturing a device that can be used to

Aidan McNally

2004-01-01

20

Field-focusing hyperthermia and magnetic resonance imaging (MRI) with a grounded probe and a commercial MRI scanner.  

PubMed

A method for performing magnetic resonance imaging (MRI) and producing field-focusing hyperthermia sequentially in phantoms and rat tissues with a grounded hyperthermic probe and a commercial MRI scanner was demonstrated. In the treatment mode the MRI scanner was used as a radiofrequency (RF) power source, and an invasive, electrically grounded, tuned probe was used to produce hyperthermia in phantoms via induced eddy current convergence. Temperature increases of 4.5 degrees C/5 minutes in a dielectrically uniform phantom and 5.0 degrees C/6 minutes in the peritoneum of a rat were measured in the vicinity (3-5 mm) of the grounded probe with the transmitter of the MRI scanner working at 2 per cent duty cycle. The advantage of this combined diagnostic and therapeutic approach is that the position of the hyperthermic probe can be monitored before each treatment, with observation of the tumor during and after treatment, if desired. In addition, the total cost is significantly less than that of both an MRI scanner and an RF hyperthermia treatment system. PMID:4058345

Yamanashi, W S; Fesen, M R; Anderson, D W; SY, A M; Lester, P D

1985-01-01

21

MRI compatible small animal monitoring and trigger system for whole body scanners.  

PubMed

Performing magnetic resonance imaging (MRI) experiments with small animals requires continuous monitoring of vital parameters, especially the respiration rate. Clinical whole-body MR scanners represent an attractive option for preclinical imaging as dedicated animal scanners are cost-intensive in both investment and maintenance, thus limiting their availability. Even though impressive image quality is achievable with clinical MR systems in combination with special coils, their built-in physiologic monitoring and triggering units are often not suited for small animal imaging. In this work, we present a simple, MRI compatible low cost solution to monitor the respiration and heart rate of small animals in a clinical whole-body MR scanner. The recording and processing of the biosignals as well as the optimisation of the respiratory trigger generation is decribed. Additionally rat and mouse in-vivo MRI experiments are presented to illustrate the effectiveness of the monitoring and respiratory trigger system in suppressing motion artifacts. PMID:23962379

Herrmann, Karl-Heinz; Pfeiffer, Norman; Krumbein, Ines; Herrmann, Lutz; Reichenbach, Jrgen R

2014-03-01

22

While today's clinical MRI scanners are limited to magnetic fields of 3 T, researchers visiting the NHMFL now can perform MRI  

E-print Network

While today's clinical MRI scanners are limited to magnetic fields of 3 T, researchers visiting the NHMFL now can perform MRI research at 21.1 T in the world's only 900-MHz ultra-widebore (105-mm) vertical magnet. Several challenges were addressed to perform research using MRI in very high field

Weston, Ken

23

Cerebral microvascular lesions on high-resolution 7-tesla MRI in patients with type 2 diabetes.  

PubMed

Cerebral small vessel disease, including microvascular lesions, is considered to play an important role in the development of type 2 diabetes mellitus (T2DM)-associated cognitive deficits. With ultra-high field MRI, microvascular lesions (e.g., microinfarcts and microbleeds) can now be visualized in vivo. For the current study, 48 nondemented older individuals with T2DM (mean age 70.3 4.1 years) and 49 age-, sex-, and education-matched control subjects underwent a 7-Tesla brain MRI scan and a detailed cognitive assessment. The occurrence of cortical microinfarcts and cerebral microbleeds was assessed on fluid-attenuated inversion recovery and T1-weighted and T2*-weighted images, respectively, compared between the groups, and related to cognitive performance. Microinfarcts were found in 38% of control subjects and 48% of patients with T2DM. Microbleeds were present in 41% of control subjects and 33% of patients (all P > 0.05). The presence and number of microinfarcts or microbleeds were unrelated to cognitive performance. This study showed that microvascular brain lesions on ultra-high field MRI are not significantly more common in well-controlled patients with T2DM than in control subjects. PMID:24760137

Brundel, Manon; Reijmer, Yael D; van Veluw, Susanne J; Kuijf, Hugo J; Luijten, Peter R; Kappelle, L Jaap; Biessels, Geert Jan

2014-10-01

24

MRI from 400 gauss to 1.5 tesla and beyond  

NASA Astrophysics Data System (ADS)

Magnetic Resonance Imaging (MRI) is arguably the most novel and important medical imaging modality since the advent of the X-ray. MRI grew out of the long development of atomic spectroscopy, atomic and molecular beam resonance and, finally, nuclear magnetic resonance (NMR) in condensed matter. The operation and economics of MRI systems depend on the performance of magnets, pulsed magnetic field gradient windings and rf (radiofrequency) coils. Physics and physicists have made critical contributions to these technologies. Superconducting magnets have come to be the magnet of choice. Magnetic gradient windings present theoretical electromagnetic and practical challenges. The need for rf antennas that resonate at high frequencies while surrounding sizable spatial regions inspired large coils producing uniform rf magnetic fields while minimizing electric field interactions with the imaging subject. This development enabled MRI at high magnetic fields. Additionally it is possible to use arrays of small rf coils to obtain MRI images with the high signal-to-noise ratio of a small surface coil and the field of view of a large coil. We recently investigated the intense acoustic noise (110 dB or more) produced in MRI scanners. Surprisingly, eddy currents induced in the magnet cryostat inner bore make a major contribution to this noise. Calculations indicate that a thin layer of Cu on the outside of the gradient assembly could substantially decrease eddy currents and help reduce noise. GE R&D work was focused on the science underlying MRI, MRI technology and the MRI product. Corporate management sometimes discourages technical publication related to evolving products because it might help rivals. Our practice of extensive publication and participation in open scientific exchange---after filing appropriate patent applications---served as quality control for company science and technology. GE conference presentations and journal publications helped establish technical leadership and determine which ideas were most important. GE scientists built reputations leading to leadership prominent within the MRI technical community. Openness underpinned a highly effective development process that enabled GE to pull ahead of competitors.

Edelstein, William

2006-03-01

25

Development of a PET Scanner for Simultaneously Imaging Small Animals with MRI and PET  

PubMed Central

Recently, positron emission tomography (PET) is playing an increasingly important role in the diagnosis and staging of cancer. Combined PET and X-ray computed tomography (PET-CT) scanners are now the modality of choice in cancer treatment planning. More recently, the combination of PET and magnetic resonance imaging (MRI) is being explored in many sites. Combining PET and MRI has presented many challenges since the photo-multiplier tubes (PMT) in PET do not function in high magnetic fields, and conventional PET detectors distort MRI images. Solid state light sensors like avalanche photo-diodes (APDs) and more recently silicon photo-multipliers (SiPMs) are much less sensitive to magnetic fields thus easing the compatibility issues. This paper presents the results of a group of Canadian scientists who are developing a PET detector ring which fits inside a high field small animal MRI scanner with the goal of providing simultaneous PET and MRI images of small rodents used in pre-clinical medical research. We discuss the evolution of both the crystal blocks (which detect annihilation photons from positron decay) and the SiPM array performance in the last four years which together combine to deliver significant system performance in terms of speed, energy and timing resolution. PMID:25120157

Thompson, Christopher J; Goertzen, Andrew L; Thiessen, Jonathan D; Bishop, Daryl; Stortz, Greg; Kozlowski, Piotr; Retiere, Fabrice; Zhang, Xuezhu; Sossi, Vesna

2014-01-01

26

Detection of hippocampal atrophy in patients with temporal lobe epilepsy: a 3-Tesla MRI shape.  

PubMed

In patients with mesial temporal lobe epilepsy (MTLE), brain MRI often detects hippocampal sclerosis (HS). Almost half of patients with MTLE do not show any hippocampal damage on visual or volumetric assessment. Here, we wished to prospectively assess 65 patients with MTLE (41 women, mean age: 3910years, range: 21-69; right (12/65 patients) (MRI-negative) nMTLE; right (14/65 patients) (MRI-positive with HS) pMTLE; left (24/65 patients) nMTLE; and left (15/65 patients) pMTLE) using shape analysis (SA). There were significant differences among pMTLE versus nMTLE for age at seizure onset (20.212.8 vs. 31.816.7years; p=.0029), duration of epilepsy (14.612.7 vs. 21.39.6years; p=.0227), risk of refractoriness (p=.0067), frequency of antecedent febrile convulsions (FCs) (p<.001), as well as a history of epilepsy or FCs (p=.0104). All the subjects underwent the same 3-Tesla MRI protocol. Shape analysis of hippocampal formation was conducted comparing each group versus 44 matched controls. In all four subgroups, SA detected a significant atrophy in the corresponding hippocampus that coincided with the epileptogenic area. The damage was significantly more severe in patients with pMTLE (F value: 5.00) than in subgroups with nMTLE (F value: 3.50) and mainly corresponded to the CA1 subregion and subiculum. In the patients with MTLE, SA detects hippocampal damage that lateralizes with the epileptogenic area. Such damage is most prominent in the CA1 subregion and subiculum that are crucial in the pathogenesis of MTLE. PMID:23892579

Mumoli, Laura; Labate, Angelo; Vasta, Roberta; Cherubini, Andrea; Ferlazzo, Edoardo; Aguglia, Umberto; Quattrone, Aldo; Gambardella, Antonio

2013-09-01

27

Clinical Evaluation of Stereotactic Target Localization Using 3-Tesla MRI for Radiosurgery Planning  

SciTech Connect

Purpose: Increasing the magnetic resonance imaging (MRI) field strength can improve image resolution and quality, but concerns remain regarding the influence on geometric fidelity. The objectives of the present study were to spatially investigate the effect of 3-Tesla (3T) MRI on clinical target localization for stereotactic radiosurgery. Methods and Materials: A total of 39 patients were enrolled in a research ethics board-approved prospective clinical trial. Imaging (1.5T and 3T MRI and computed tomography) was performed after stereotactic frame placement. Stereotactic target localization at 1.5T vs. 3T was retrospectively analyzed in a representative cohort of patients with tumor (n = 4) and functional (n = 5) radiosurgical targets. The spatial congruency of the tumor gross target volumes was determined by the mean discrepancy between the average gross target volume surfaces at 1.5T and 3T. Reproducibility was assessed by the displacement from an averaged surface and volume congruency. Spatial congruency and the reproducibility of functional radiosurgical targets was determined by comparing the mean and standard deviation of the isocenter coordinates. Results: Overall, the mean absolute discrepancy across all patients was 0.67 mm (95% confidence interval, 0.51-0.83), significantly <1 mm (p < .010). No differences were found in the overall interuser target volume congruence (mean, 84% for 1.5T vs. 84% for 3T, p > .4), and the gross target volume surface mean displacements were similar within and between users. The overall average isocenter coordinate discrepancy for the functional targets at 1.5T and 3T was 0.33 mm (95% confidence interval, 0.20-0.48), with no patient-specific differences between the mean values (p >.2) or standard deviations (p >.1). Conclusion: Our results have provided clinically relevant evidence supporting the spatial validity of 3T MRI for use in stereotactic radiosurgery under the imaging conditions used.

MacFadden, Derek [University of Toronto Faculty of Medicine, Toronto, ON (Canada); Zhang Beibei; Brock, Kristy K. [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Hodaie, Mojgan [Division of Neurosurgery, Toronto Western Hospital, Toronto, ON (Canada); Laperriere, Normand [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Schwartz, Michael [Division of Neurosurgery, Toronto Western Hospital, Toronto, ON (Canada); Tsao, May [Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Department of Radiation Oncology, Sunnybrook Regional Cancer Centre, Toronto, ON (Canada); Stainsby, Jeffrey [Applied Science Laboratories, GE Healthcare, Mississauga, ON (Canada); Lockwood, Gina [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Mikulis, David [Department of Medical Imaging, University Health Network, Toronto, ON (Canada); Menard, Cynthia, E-mail: cynthia.menard@rmp.uhn.on.c [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada)

2010-04-15

28

3D Localized 2D NMR Spectroscopy on an MRI Scanner  

Microsoft Academic Search

Three-dimensionally localized versions of several two-dimensional NMR sequences have been implemented on a 1.5 T whole-body MRI\\/MRS scanner. In addition to the localization of voxels, the slice-selective RF pulses were also used for refocusing\\/transfer of various coherences in the 2D NMR sequences. Initial phantom and in vivo human studies are presented here. The sequences were localized versions of 2D J-resolved,

L. N. Ryner; J. A. Sorenson; M. A. Thomas

1995-01-01

29

Characterization of Ballistocardiogram Recorded at 1.5 and 3.0 Tesla in Simultaneous EEG-fMRI Zempel, J. M., Vincent, J. L., Larson-Prior, L. J., and Snyder, A. Z.  

E-print Network

Characterization of Ballistocardiogram Recorded at 1.5 and 3.0 Tesla in Simultaneous EEG of BKG at 1.5 and 3.0 Tesla: ·3 subjects Experimental protocol: ·Functional images were simultaneously in the scanner (1.5 and 3 Tesla) with the same EEG equipment (amplifier, cap, cables) in consecutive sessions. ·3

Larson-Prior, Linda

30

Ultrahigh-Field MRI in Human Ischemic Stroke - a 7 Tesla Study  

PubMed Central

Introduction Magnetic resonance imaging (MRI) using field strengths up to 3 Tesla (T) has proven to be a powerful tool for stroke diagnosis. Recently, ultrahigh-field (UHF) MRI at 7 T has shown relevant diagnostic benefits in imaging of neurological diseases, but its value for stroke imaging has not been investigated yet. We present the first evaluation of a clinically feasible stroke imaging protocol at 7 T. For comparison an established stroke imaging protocol was applied at 3 T. Methods In a prospective imaging study seven patients with subacute and chronic stroke were included. Imaging at 3 T was immediately followed by 7 T imaging. Both protocols included T1-weighted 3D Magnetization-Prepared Rapid-Acquired Gradient-Echo (3D-MPRAGE), T2-weighted 2D Fluid Attenuated Inversion Recovery (2D-FLAIR), T2-weighted 2D Fluid Attenuated Inversion Recovery (2D-T2-TSE), T2* weighted 2D Fast Low Angle Shot Gradient Echo (2D-HemoFLASH) and 3D Time-of-Flight angiography (3D-TOF). Results The diagnostic information relevant for clinical stroke imaging obtained at 3 T was equally available at 7 T. Higher spatial resolution at 7 T revealed more anatomical details precisely depicting ischemic lesions and periinfarct alterations. A clear benefit in anatomical resolution was also demonstrated for vessel imaging at 7 T. RF power deposition constraints induced scan time prolongation and reduced brain coverage for 2D-FLAIR, 2D-T2-TSE and 3D-TOF at 7 T versus 3 T. Conclusions The potential of 7 T MRI for human stroke imaging is shown. Our pilot study encourages a further evaluation of the diagnostic benefit of stroke imaging at 7 T in a larger study. PMID:22701525

Bauer, Miriam; Stengl, Katharina L.; Mutke, Matthias A.; Tovar-Martinez, Elena; Wuerfel, Jens; Endres, Matthias; Niendorf, Thoralf; Sobesky, Jan

2012-01-01

31

The Interconnection of MRI Scanner and MR-Compatible Robotic Device: Synergistic Graphical User Interface to Form a Mechatronic System  

PubMed Central

MRI scanner and magnetic resonance (MR)-compatible robotic devices are mechatronic systems. Without an interconnecting component, these two devices cannot be operated synergetically for medical interventions. In this paper, the design and properties of a graphical user interface (GUI) that accomplishes the task is presented. The GUI interconnects the two devices to obtain a larger mechatronic system by providing command and control of the robotic device based on the visual information obtained from the MRI scanner. Ideally, the GUI should also control imaging parameters of the MRI scanner. Its main goal is to facilitate image-guided interventions by acting as the synergistic component between the physician, the robotic device, the scanner, and the patient. PMID:21544216

Ozcan, Alpay; Tsekos, Nikolaos

2011-01-01

32

Ventricular Assist Device implant (AB 5000) prototype cannula: In vitro assessment of MRI issues at 3-Tesla  

PubMed Central

Purpose To evaluate MRI issues at 3-Tesla for a ventricular assist device (VAD). Methods The AB5000 Ventricle with a prototype Nitinol wire-reinforced In-Flow Cannula and Out-Flow Cannula attached (Abiomed, Inc., Danvers, MA) was evaluated for magnetic field interactions, heating, and artifacts at 3-Tesla. MRI-related heating was assessed with the device in a gelled-saline-filled, head/torso phantom using a transmit/received RF body coil while performing MRI at a whole body averaged SAR of 3-W/kg for 15-min. Artifacts were assessed for the main metallic component of this VAD (atrial cannula) using T1-weighted, spin echo and gradient echo pulse sequences. Results The AB5000 Ventricle with the prototype In-Flow Cannula and Out-Flow Cannula attached showed relatively minor magnetic field interactions that will not cause movement in situ. Heating was not excessive (highest temperature change, +0.8C). Artifacts may create issues for diagnostic imaging if the area of interest is in the same area or close to the implanted metallic component of this VAD (i.e., the venous cannula). Conclusion The results of this investigation demonstrated that it would be acceptable for a patient with this VAD (AB5000 Ventricle with a prototype Nitinol wire-reinforced In-Flow Cannula and Out-Flow Cannula attached) to undergo MRI at 3-Tesla or less. Notably, it is likely that the operation console for this device requires positioning a suitable distance (beyond the 100 Gauss line or in the MR control room) from the 3-Tesla MR system to ensure proper function of the VAD. PMID:18495028

Shellock, Frank G; Valencerina, Samuel

2008-01-01

33

Journal of Neuroscience Methods 169 (2008) 7683 Visual stimulus presentation using fiber optics in the MRI scanner  

E-print Network

-face space using fiber optics in the MRI scanner. The feasibility of fiber-optic based displays. Keywords: fMRI; Fiber optics; 3-D stimuli; Peripersonal space; Near-face space 1. Introduction FunctionalJournal of Neuroscience Methods 169 (2008) 76­83 Visual stimulus presentation using fiber optics

Sereno, Martin

34

FALL STrUCTUrE, dYNAMiCS & FUNCTiON Mouse in-vivo MRI probe and proton RF coil for the UWB 900 MRI scanner.  

E-print Network

FALL STrUCTUrE, dYNAMiCS & FUNCTiON Figure 1. Mouse in-vivo MRI probe and proton RF coil for the UWB 900 MRI scanner. In vivo Mr imaging at 21.1 T Victor D. Schepkin, Samuel C. Grant and Timothy A imaging experiments using the Magnet lab world-record 900 uWB magnet. ExpEriMENTAL Testing the in vivo Mri

Weston, Ken

35

Effect of scanner acoustic background noise on strict resting-state fMRI  

PubMed Central

Functional MRI (fMRI) resting-state experiments are aimed at identifying brain networks that support basal brain function. Although most investigators consider a resting-state fMRI experiment with no specific external stimulation, subjects are unavoidably under heavy acoustic noise produced by the equipment. In the present study, we evaluated the influence of auditory input on the resting-state networks (RSNs). Twenty-two healthy subjects were scanned using two similar echo-planar imaging sequences in the same 3T MRI scanner: a default pulse sequence and a reduced silent pulse sequence. Experimental sessions consisted of two consecutive 7-min runs with noise conditions (default or silent) counterbalanced across subjects. A self-organizing group independent component analysis was applied to fMRI data in order to recognize the RSNs. The insula, left middle frontal gyrus and right precentral and left inferior parietal lobules showed significant differences in the voxel-wise comparison between RSNs depending on noise condition. In the presence of low-level noise, these areas Granger-cause oscillations in RSNs with cognitive implications (dorsal attention and entorhinal), while during high noise acquisition, these connectivities are reduced or inverted. Applying low noise MR acquisitions in research may allow the detection of subtle differences of the RSNs, with implications in experimental planning for resting-state studies, data analysis, and ergonomic factors. PMID:23579634

Rondinoni, C.; Amaro, E.; Cendes, F.; Santos, A.C.dos; Salmon, C.E.G.

2013-01-01

36

Functionality of veterinary identification microchips following low- (0.5 tesla) and high-field (3 tesla) magnetic resonance imaging.  

PubMed

The ability to read patient identification microchips relies on the use of radiofrequency pulses. Since radiofrequency pulses also form an integral part of the magnetic resonance imaging (MRI) process, the possibility of loss of microchip function during MRI scanning is of concern. Previous clinical trials have shown microchip function to be unaffected by MR imaging using a field strength of 1 Tesla and 1.5. As veterinary MRI scanners range widely in field strength, this study was devised to determine whether exposure to lower or higher field strengths than 1 Tesla would affect the function of different types of microchip. In a phantom study, a total of 300 International Standards Organisation (ISO)-approved microchips (100 each of three different types: ISO FDX-B 1.4 9 mm, ISO FDX-B 2.12 12 mm, ISO HDX 3.8 23 mm) were tested in a low field (0.5) and a high field scanner (3.0 Tesla). A total of 50 microchips of each type were tested in each scanner. The phantom was composed of a fluid-filled freezer pack onto which a plastic pillow and a cardboard strip with affixed microchips were positioned. Following an MRI scan protocol simulating a head study, all of the microchips were accurately readable. Neither 0.5 nor 3 Tesla imaging affected microchip function in this study. PMID:23763334

Piesnack, Susann; Frame, Mairi E; Oechtering, Gerhard; Ludewig, Eberhard

2013-01-01

37

First CT-MRI Scanner for Multi-dimensional Synchrony and Multi-physical Coupling  

E-print Network

We propose to prototype the first CT-MRI scanner for radiation therapy and basic research, demonstrate its transformative biomedical potential, and initiate a paradigm shift in multimodality imaging. Our design consists of a double donut-shaped pair of permanent magnets to form a regionally uniform ~0.5T magnetic field and leave room for a stationary 9-source interior CT gantry at 3 tube voltages (triple-energy CT). Image reconstruction will be in a compressive sensing framework. Please discuss with Dr. Ge Wang (ge-wang@ieee.org) if you are interested in collaborative opportunities.

Wang, Ge

2014-01-01

38

Evaluation of Artifacts and Distortions of Titanium Applicators on 3.0-Tesla MRI: Feasibility of Titanium Applicators in MRI-Guided Brachytherapy for Gynecological Cancer  

SciTech Connect

Purpose: The aim of this study was to characterize the levels of artifacts and distortions of titanium applicators on 3.0-Tesla magnetic resonance imaging (MRI). Methods and Materials: Fletcher-Suit-Delclos-style tandem and ovoids (T and O) and tandem and ring applicator (T and R) were examined. The quality assurance (QA) phantoms for each applicator were designed and filled with copper sulphate solution (1.5 g/l). The artifacts were quantified with the registration of corresponding computed tomography (CT) images. A favorable MR sequence was searched in terms of artifacts. Using the sequence, the artifacts were determined. The geometric distortions induced by the applicators were quantified through each registration of CT and MRI without applicators. The artifacts of T and O were also evaluated on in vivo MRI datasets of 5 patients. Results: T1-weighted MRI with 1-mm slice thickness was found as a favorable MR sequence. Applying the sequence, the artifacts at the tandem tip of T and O and T and R were determined as 1.5 {+-} 0.5 mm in a superior direction in phantom studies. In the ovoids of T and O, we found artifacts less than 1.5 {+-} 0.5 mm. The artifacts of a T and O tandem in vivo were found as less than 2.6 {+-} 1.3 mm on T1-weighted MRI, whereas less than 6.9 {+-} 3.4 mm on T2-weighted MRI. No more than 1.2 {+-} 0.6 mm (3.0 {+-} 1.5 mm) of distortions, due to a titanium applicator, were measured on T1-weighted MRI (T2-). Conclusion: In 3.0-Tesla MRI, we found the artifact widths at the tip of tandem were less than 1.5 {+-} 0.5 mm for both T and O and T and R when using T1-weighted MRI in phantom studies. However, exclusive 3.0-Tesla MRI-guided brachytherapy planning with a titanium applicator should be cautiously implemented.

Kim, Yusung, E-mail: yusung-kim@uiowa.edu [Department of Radiation Oncology, University of Iowa, Iowa City, IA (United States); Muruganandham, Manickam; Modrick, Joseph M.; Bayouth, John E. [Department of Radiation Oncology, University of Iowa, Iowa City, IA (United States)

2011-07-01

39

Steering of aggregating magnetic microparticles using propulsion gradients coils in an MRI Scanner.  

PubMed

Upgraded gradient coils can effectively enhance the MRI steering of magnetic microparticles in a branching channel. Applications of this method include MRI targeting of magnetic embolization agents for oncologic therapy. A magnetic suspension of Fe(3)O(4) magnetic particles was injected inside a y-shaped microfluidic channel. Magnetic gradients of 0, 50, 100, 200, and 400 mT/m were applied to the magnetic particles perpendicularly to the flow by a custom-built gradient coil inside a 1.5-T MRI scanner. Measurement of the steering ratio was performed both by video analyses and quantification of the mass of the particles collected at each outlet of the microfluidic channel, using atomic absorption spectroscopy. Magnetic particles steering ratios of 0.99 and 0.75 were reached with 400 mT/m gradient amplitude and measured by video analyses and atomic absorption spectroscopy, respectively. Experimental data shows that the steering ratio increases with higher magnetic gradients. Moreover, theory suggests that larger particles (or aggregates), higher magnetizations, and lower flows can also be used to improve the steering ratio. The technological limitation of the approach is that an MRI gradient amplitude increase to a few hundred milliteslas per meter is needed. A simple analytical method based on magnetophoretic velocity predictions and geometric considerations is proposed for steering ratio calculation. PMID:20432304

Mathieu, Jean-Baptiste; Martel, Sylvain

2010-05-01

40

Ag/AgCl electrodes in the EEG/fMRI method in 3T MRI scanner  

NASA Astrophysics Data System (ADS)

This study focuses on the comparison of two different types of EEG electrodes (the first B10-S-150 Ag/AgCl sintered ring electrode with 1, 5 mm touch proof safety socket and 150 cm heavy-duty lead wire and the second, B12-LS-100 Ag/AgCl sintered FE-electrode with 100 cm light-duty lead wire and 1, 5 mm touch proof safety socket with 5 k? resistor near sensor) used in the EEG/fMRI method in 3T MRI scanner. We compared these electrodes by their specific absorption rate (SAR) simulation values and the temperature change calculated by PRF method. The experimental setup of the study is described as follows: a phantom is prepared and the electrodes are placed on it. Then, a simulation for SAR values is realized. The temperature change is calculated by MR thermometer. As a result of this study, Ag/AgCl pin electrode is better to be use in EEG/fMRI; because the measured temperature change is expected to be low.

Akay, Cengiz; Kepceo?lu, Abdullah

2013-10-01

41

Feasibility study using MRI and two optical CT scanners for readout of polymer gel and PresageTM  

NASA Astrophysics Data System (ADS)

The aim of this study was to compare the conventional combination of three-dimensional dosimeter (nPAG gel) and readout method (MRI) with other combinations of three-dimensional dosimeters (nPAG gel/PresageTM) and readout methods (optical CT scanners). In the first experiment, the dose readout of a gel irradiated with a four field-box technique was performed with both an Octopus IQ scanner and MRI. It was seen that the MRI readout agreed slightly better to the TPS. In another experiment, a gel and a PresageTM sample were irradiated with a VMAT field and read out using MRI and a fast laser scanner, respectively. A comparison between the TPS and the volumes revealed that the MRI/gel readout had closer resemblance to the TPS than the optical CT/PresageTM readout. There are clearly potential in the evaluated optical CT scanners, but more time has to be invested in the particular scanning scenario than was possible in this study.

Svensson, H.; Skyt, P. S.; Ceberg, S.; Doran, S.; Muren, L. P.; Balling, P.; Petersen, J. B. B.; Bck, S. . J.

2013-06-01

42

Studies of the interactions of an MRI system with the shielding in a combined PET/MRI scanner  

PubMed Central

A positron emission tomography (PET) system or insert has been constructed for placement and operation in the bore of a small animal magnetic resonance imaging (MRI) scanner to allow simultaneous MR and PET imaging. The insert contains electronics, components with a variety of magnetic properties, and large continuous sheets of metal all characteristics of an object that should, by conventional wisdom, never be placed in the bore of an MR scanner, especially near the imaging volume. There are a variety of ways the two systems might be expected to interact that could negatively impact the performance of either or both. In this article, the interaction mechanisms, particularly the impacts of the PET insert and shielding on MR imaging, are defined and explored. Additionally, some of the difficulties in quantifying errors introduced into the MR images as a result of the presence of the PET components are demonstrated. Several different approaches are used to characterize image artifacts and determine optimal placement of the shielding. Data are also presented that suggest ways the shielding could be modified to reduce errors and enable placement closer to the isocenter of the magnet. PMID:20009193

Peng, Bo J.; Walton, Jeffrey H.; Cherry, Simon R.; Willig-Onwuachi, Jacob

2010-01-01

43

Relationship of Clinical and Cognitive Variables with Brain Morphometric Abnormalities in Alzheimer's Disease: a Voxel Based Morphometric Study Using 3-Tesla MRI  

PubMed Central

Alzheimers disease (AD) is associated with widespread structural and functional brain alterations. The current study examined the gray matter (GM) voxel based morphometric (VBM) correlates of cognitive and clinical severity scores in patients with AD. The study included 34 patients with AD according to NINCDS/ADRDA AD criteria and 28 matched elderly controls. All subjects were clinically evaluated using Hindi Mental Status Examination (HMSE), Everyday Abilities Scale for India (EASI) and the Clinical Dementia Rating (CDR) scale. The structural Magnetic Resonance Imaging (MRI) data were acquired using a 3 Tesla MRI scanner and VBM analysis was performed using VBM5.1 toolbox. The patients with AD had significantly lower GM volume, white matter volume and total brain volume as compared to controls. The HMSE scores were positively correlated (p=0.009) and EASI (p=0.04) & CDR (p=0.0004) were negatively correlated with the total GM volumes in patients with AD. The VBM analysis revealed diffuse GM atrophy in patients with AD. Frontal& temporal GM volumes were positively correlated with the HMSE scores. Thus the results of the study replicate the previous observations of generalized GM atrophy, in an Indian sample with AD. The cognitive decline, clinical dementia severity and impairment in activities of daily living were correlated whole brain GM and WM volumes as well as with specific brain regional atrophy in AD. However further studies with larger samples & with more detailed cognitive evaluation are required for confirmation & validation of the relationship between regional morphometric abnormalities and cognitive deficits in AD. PMID:24124629

Bagepally, Bhavani S.; John, John P.; Varghese, Mathew; Halahalli, Harsha N.; Kota, Lakshminarayanan; Sivakumar, Palanimuthu T.; Bharath, Srikala; Jain, Sanjeev

2013-01-01

44

Measuring and shimming the magnetic field of a 4 Tesla MRI magnet  

E-print Network

The Biomedical Magnetic Resonance Laboratory (BMRL) of the University of Illinois at Urbana-Champaign (UIUC) has ordered from the Texas Accelerator Center (TAC) a superconducting, self-shielded, solenoidal magnet with a maximum field of 4 Tesla...

Kyriazis, Georgios

2012-06-07

45

Imaging pH phantoms using magnetization transfer technology at 1.5 Tesla  

Microsoft Academic Search

Magnetization transfer (MT) is an important source of contrast in magnetic resonance imaging (MRI), and is the basis of chemical exchange saturation transfer (CEST) imaging, which does not exist in our clinical MR scanner at 1.5 Tesla (T). Amide proton transfer (APT) imaging, a variant of CEST imaging, has been shown capable of detecting tissue acidosis during stroke at above

Maobin Wei; Zhiwei Shen; Gang Xiao; Renhua Wu; Qingchun Qiu; Yaowen Chen

2011-01-01

46

Support system design incorporating carbon/epoxy tension straps for a four tesla, one meter bore, MRI magnet  

SciTech Connect

The Texas Accelerator Center (TAC) constructed a four tesla, one meter bore, MRI magnet. Graphite/epoxy tension straps with thermal intercepts at 77 K and 20 K were used for a safe, efficient, and cost effective support system. Sixteen straps were used to support the 10,400 kg cold mass. TAC used a superferric concept to restrict the fringe field. With proper alignment the attractive forces between the magnet and iron are designed to cancel. Therefore, easy adjustment for proper positioning of the magnet, and strength to withstand the magnetic forces due to any misalignment are requirements of the support system. Since the MRI magnet was shipped by truck, the support system had to withstand dynamic loads. The design conduction heat load to the cold mass is 0.05 W. Details of the support system are presented.

Watts, L.C. [RPM Engineering, Baton Rouge, LA (United States); Boulios, K. [Texas Accelerator Center, The Woodlands, TX (United States); Hartwig, K.T. [Texas A& M Univ., College Station, TX (United States)] [and others

1996-12-31

47

Nuclear Instruments and Methods in Physics Research A 571 (2007) 102105 Preliminary studies of a simultaneous PET/MRI scanner based on the  

E-print Network

of a simultaneous PET/MRI scanner based on the RatCAP small animal tomograph C. Woodya,?, D. Schlyera , P. Vaskaa of high resolution anatomical data using magnetic resonance imaging (MRI) and quantitative physiological of this detector used for simultaneous PET/MRI imaging will be constructed out of all nonmagnetic materials

48

High Resolution Wall and Lumen MRI of the Middle Cerebral Arteries at 3 Tesla  

Microsoft Academic Search

Background: Although black-blood MRI (BB-MRI) can identify plaques in the cervical carotid arteries, this modality has not been applied in intracranial arteries. We imaged the lumina and walls of stenotic middle cerebral arteries (MCAs) in symptomatic and asymptomatic patients using high-resolution BB-MRI, in order to characterize vulnerable plaques and to determine the diagnostic accuracy of BB-MRI in MCA stenosis. Methods:

Chang-Woo Ryu; Geon-Ho Jahng; Eui-Jong Kim; Woo-Suk Choi; Dal-Mo Yang

2009-01-01

49

Silicone made contractile dielectric elastomer actuators inside 3Tesla MRI environment  

Microsoft Academic Search

New actuators are greatly demanded today in order to develop magnetic resonance imaging (MRI)- compatible mechatronic systems capable of extended and improved capabilities. They are particularly needed for MRI- guided interventional or rehabilitation procedures. Actuators based on dielectric elastomers, a specific class of electroactive polymers, appear as suitable candidates for new MRI- compatible technologies, due to their intrinsic material properties

Federico Carpi; Azadeh Khanicheh; Constantinos Mavroidis; Danilo De Rossi

2008-01-01

50

3D Localized 2D NMR Spectroscopy on an MRI Scanner  

NASA Astrophysics Data System (ADS)

Three-dimensionally localized versions of several two-dimensional NMR sequences have been implemented on a 1.5 T whole-body MRI/MRS scanner. In addition to the localization of voxels, the slice-selective RF pulses were also used for refocusing/transfer of various coherences in the 2D NMR sequences. Initial phantom and in vivo human studies are presented here. The sequences were localized versions of 2D J-resolved, 2D zero-quantum, 2D double-quantum, zero-quantum-filtered COSY and SECSY, and double-quantum-filtered COSY and SECSY. Two-dimensional plots for the J-resolved and multiple-quantum sequences are presented for a phantom containing an aqueous solution of 10 m M alanine. Sensitivity of different multiple-quantum-coherence orders to B0 inhomogeneity is discussed. Localized double-quantum-filtered COSY of a phantom containing physiological concentrations of several metabolites also is presented to demonstrate the feasibility of performing this technique within time limits reasonable for human comfort. The first-reported 2D J-resolved 1H in vivo MR spectrum localized in three dimensions in presented here, acquired predominantly from the cerebral white matter of a healthy volunteer and demonstrating the use of localized 2D NMR techniques in vivo.

Ryner, L. N.; Sorenson, J. A.; Thomas, M. A.

51

A study-specific fMRI normalization approach that operates directly on high resolution functional EPI data at 7 Tesla.  

PubMed

Due to the availability of ultra-high field scanners and novel imaging methods, high resolution, whole brain functional MR imaging (fMRI) has become increasingly feasible. However, it is common to use extensive spatial smoothing to account for inter-subject anatomical variation when pooling over subjects. This reduces the spatial details of group level functional activation considerably, even when the original data was acquired with high resolution. In our study we used an accelerated 3D EPI sequence at 7 Tesla to acquire whole brain fMRI data with an isotropic spatial resolution of 1.1mm which shows clear gray/white matter contrast due to the stronger T1 weighting of 3D EPI. To benefit from the high spatial resolution on the group level, we develop a study specific, high resolution anatomical template which is facilitated by the good anatomical contrast that is present in the average functional EPI images. Different template generations with increasing accuracy were created by using a hierarchical linear and stepwise non-linear registration approach. As the template is based on the functional data themselves no additional co-registration step with the usual T1-weighted anatomical data is necessary which eliminates a potential source of misalignment. To test the improvement of functional localization and spatial details we performed a group level analysis of a finger tapping experiment in eight subjects. The most accurate template shows better spatial localization--such as a separation of somatosensory and motor areas and of single digit activation--compared to the simple linear registration. The number of activated voxels is increased by a factor of 1.2, 2.5, and 3.1 for somatosensory, supplementary motor area, and dentate nucleus, respectively, for the functional contrast between left versus right hand. Similarly, the number of activated voxels is increased 1.4- and 2.4-fold for right little versus right index finger and left little versus left index finger, respectively. The Euclidian distance between the activation (center of gravity) of the respective fingers was found to be 13.90 mm using the most accurate template. PMID:24973602

Grabner, Gnther; Poser, Benedikt A; Fujimoto, Kyoko; Polimeni, Jonathan R; Wald, Lawrence L; Trattnig, Siegfried; Toni, Ivan; Barth, Markus

2014-10-15

52

Quantitative Apparent Diffusion Coefficient Measurements Obtained by 3-Tesla MRI Are Correlated with Biomarkers of Bladder Cancer Proliferative Activity  

PubMed Central

Purpose To investigate the association between Apparent Diffusion Coefficient (ADC) values and cell cycle and proliferative biomarkers (p53, p21, Ki67,) in order to establish its potential role as a noninvasive biomarker for prediction of cell cycle, proliferative activity and biological aggressiveness in bladder cancer. Materials and Methods Patients with bladder cancer who underwent 3,0 Tesla DW-MRI of the bladder before TUR-B or radical cystectomy were eligible for this prospective IRB-approved study. Histological specimen were immunohistochemically stained for the following markers: p53, p21 and ki67. Two board-certified uropathologists reviewed the specimens blinded to DW-MRI results. Histological grade and T-stage were classified according to the WHO 2004 and the 2009 TNM classification, respectively. Nonparametric univariate and multivariate statistics including correlation, logistic regression and ROC analysis were applied. Results Muscle invasive bladder cancer was histologically confirmed in 10 out of 41 patients. All examined tissue biomarkers were significantly correlated with ADC values (p<0.05, respectively). Based on multivariate analysis, p53 and ADC are both independent prognostic factors for muscle invasiveness of bladder cancer (>/?=?T2). (p?=?0.013 and p?=?0.018). Conclusion ADC values are associated with cell cycle and proliferative biomarkers and do thereby reflect invasive and proliferative potential in bladder cancer. ADC and p53 are both independent prognostic factors for muscle invasiveness in bladder cancer. PMID:25202965

Sevcenco, Sabina; Haitel, Andrea; Ponhold, Lothar; Susani, Martin; Fajkovic, Harun; Shariat, Shahrokh F.; Hiess, Manuela; Spick, Claudio; Szarvas, Tibor; Baltzer, Pascal A. T.

2014-01-01

53

Numerical field simulation for parallel transmission in MRI at 7 tesla  

E-print Network

Parallel transmission (pTx) is a promising improvement to coil design that has been demonstrated to mitigate B1* inhomogeneity, manifest as center brightening, for high-field magnetic resonance imaging (MRI). Parallel ...

Bernier, Jessica A. (Jessica Ashley)

2011-01-01

54

Iron Accumulation in Deep Cortical Layers Accounts for MRI Signal Abnormalities in ALS: Correlating 7 Tesla MRI and Pathology  

PubMed Central

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by cortical and spinal motor neuron dysfunction. Routine magnetic resonance imaging (MRI) studies have previously shown hypointense signal in the motor cortex on T2-weighted images in some ALS patients, however, the cause of this finding is unknown. To investigate the utility of this MR signal change as a marker of cortical motor neuron degeneration, signal abnormalities on 3T and 7T MR images of the brain were compared, and pathology was obtained in two ALS patients to determine the origin of the motor cortex hypointensity. Nineteen patients with clinically probable or definite ALS by El Escorial criteria and 19 healthy controls underwent 3T MRI. A 7T MRI scan was carried out on five ALS patients who had motor cortex hypointensity on the 3T FLAIR sequence and on three healthy controls. Postmortem 7T MRI of the brain was performed in one ALS patient and histological studies of the brains and spinal cords were obtained post-mortem in two patients. The motor cortex hypointensity on 3T FLAIR images was present in greater frequency in ALS patients. Increased hypointensity correlated with greater severity of upper motor neuron impairment. Analysis of 7T T2*-weighted gradient echo imaging localized the signal alteration to the deeper layers of the motor cortex in both ALS patients. Pathological studies showed increased iron accumulation in microglial cells in areas corresponding to the location of the signal changes on the 3T and 7T MRI of the motor cortex. These findings indicate that the motor cortex hypointensity on 3T MRI FLAIR images in ALS is due to increased iron accumulation by microglia. PMID:22529995

Kwan, Justin Y.; Jeong, Suh Young; Van Gelderen, Peter; Deng, Han-Xiang; Quezado, Martha M.; Danielian, Laura E.; Butman, John A.; Chen, Lingye; Bayat, Elham; Russell, James; Siddique, Teepu; Duyn, Jeff H.; Rouault, Tracey A.; Floeter, Mary Kay

2012-01-01

55

Computational dosimetry of induced electric fields during realistic movements in the vicinity of a 3 T MRI scanner  

NASA Astrophysics Data System (ADS)

Medical staff working near magnetic resonance imaging (MRI) scanners are exposed both to the static magnetic field itself and also to electric currents that are induced in the body when the body moves in the magnetic field. However, there are currently limited data available on the induced electric field for realistic movements. This study computationally investigates the movement induced electric fields for realistic movements in the magnetic field of a 3 T MRI scanner. The path of movement near the MRI scanner is based on magnetic field measurements using a coil sensor attached to a human volunteer. Utilizing realistic models for both the motion of the head and the magnetic field of the MRI scanner, the induced fields are computationally determined using the finite-element method for five high-resolution numerical anatomical models. The results show that the time-derivative of the magnetic flux density (dB/dt) is approximately linearly proportional to the induced electric field in the head, independent of the position of the head with respect to the magnet. This supports the use of dB/dt measurements for occupational exposure assessment. For the path of movement considered herein, the spatial maximum of the induced electric field is close to the basic restriction for the peripheral nervous system and exceeds the basic restriction for the central nervous system in the international guidelines. The 99th percentile electric field is a considerably less restrictive metric for the exposure than the spatial maximum electric field; the former is typically 60-70% lower than the latter. However, the 99th percentile electric field may exceed the basic restriction for dB/dt values that can be encountered during tasks commonly performed by MRI workers. It is also shown that the movement-induced eddy currents may reach magnitudes that could electrically stimulate the vestibular system, which could play a significant role in the generation of vertigo-like sensations reported by people moving in a strong static magnetic field.

Laakso, Ilkka; Knnl, Sami; Jokela, Kari

2013-04-01

56

Preattentive mechanisms of change detection in early auditory cortex: a 7 Tesla fMRI study.  

PubMed

The auditory system continuously monitors the environment for irregularities in an automatic, preattentive fashion. This is presumably accomplished by two mechanisms: a sensory mechanism detects a deviant sound on the basis of differential refractoriness of neural populations sensitive to the standard and deviant sounds, whereas the cognitive mechanism reveals deviance by comparing incoming auditory information with a template derived from previous input. Using fast event-related high-resolution functional magnetic resonance imaging at 7 Tesla we show that both mechanisms can be mapped to different parts of the auditory cortex both at the group level and the single-subject level. The sensory mechanism is supported by primary auditory areas in Heschl's gyrus whereas the cognitive mechanism is implemented in more anterior secondary auditory areas. Both mechanisms are equally engaged by simple sine-wave tones and speech-related phonemes indicating that streams of speech and non-speech stimuli are processed in a similar fashion. PMID:23994180

Szycik, G R; Stadler, J; Brechmann, A; Mnte, T F

2013-12-01

57

Implementation of Vascular-space-occupancy (VASO) MRI at 7 Tesla  

PubMed Central

VASO-MRI exploits the difference between blood and tissue T1 to null blood signal and measure cerebral blood volume (CBV) changes using the residual tissue signal. VASO imaging is more difficult at higher field because of sensitivity loss due to the convergence of tissue and blood T1 values and increased contamination from BOLD effects. In addition, compared to 3T, 7T MRI suffers from increased geometrical distortions, e.g. when using echo-planar-imaging (EPI), and from increased power deposition, the latter especially problematic for the spin-echo-train sequences commonly used for VASO-MRI. Third, non-steady-state blood spin effects become substantial at 7T when only a head coil is available for radiofrequency transmit. In this study, the magnetization-transfer-enhanced-VASO (MT-VASO) approach was applied to maximize tissue-blood signal difference, which boosted SNR by 149 13% (n=7) compared to VASO. Second, a 3D fast gradient-echo sequence with low flip-angle (7) and short echo-time (1.8ms) was employed to minimize the BOLD effect and to reduce image distortion and power deposition. Finally, a magnetization-reset technique was combined with a motion-sensitized-driven-equilibrium (MSDE) approach to suppress three types of non-steady-state spins. Our initial fMRI results in normal human brains at 7T with this optimized VASO sequence showed better SNR than at 3T. PMID:22585570

Hua, Jun; Jones, Craig K.; Qin, Qin; van Zijl, Peter C. M.

2012-01-01

58

Off-resonance and detuned surface coils for B? inhomogeneity in 7-Tesla MRI  

E-print Network

A problem with high-field MRI is the lack of B1 homogeneity, particularly signal cancellation in the outer parts of the head. Here we attempt to correct this by adding surface coils. To adjust the mutual coupling, we vary ...

Zakszewski, Elizabeth K

2006-01-01

59

BOLD MRI of the human cervical spinal cord at 3 tesla  

Microsoft Academic Search

The feasibility of functional MRI of the spinal cord was investi- gated by carrying out blood oxygen-level dependent (BOLD) imaging of the human cervical spinal cord at a field of 3 T. BOLD imaging of the cervical spinal cord showed an average intensity increase of 7.0% during repeated exercise with the dominant hand with a return to baseline during rest

P. W. Stroman; P. W. Nance; L. N. Ryner

1999-01-01

60

Scanning fast and slow: current limitations of 3 Tesla functional MRI and future potential  

NASA Astrophysics Data System (ADS)

Functional MRI at 3T has become a workhorse for the neurosciences, e.g., neurology, psychology, and psychiatry, enabling non-invasive investigation of brain function and connectivity. However, BOLD-based fMRI is a rather indirect measure of brain function, confounded by fluctuation related signals, e.g. head or brain motion, brain pulsation, blood flow, intermixed with susceptibility differences close or distant to the region of neuronal activity. Even though a plethora of preprocessing strategies have been published to address these confounds, their efficiency is still under discussion. In particular, physiological signal fluctuations closely related to brain supply may mask BOLD signal changes related to "true" neuronal activation. Here we explore recent technical and methodological advancements aimed at disentangling the various components, employing fast multiband vs. standard EPI, in combination with fast temporal ICA.Our preliminary results indicate that fast (TR< 0.5s) scanning may help to identify and eliminate physiologic components, increasing tSNR and functional contrast. In addition, biological variability can be studied and task performance better correlated to other measures. This should increase specificity and reliability in fMRI studies. Furthermore, physiological signal changes during scanning may then be recognized as a source of information rather than a nuisance. As we are currently still undersampling the complexity of the brain, even at a rather coarse macroscopic level, we should be very cautious in the interpretation of neuroscientific findings, in particular when comparing different groups (e.g., age, sex, medication, pathology, etc.). From a technical point of view our goal should be to sample brain activity at layer specific resolution with low TR, covering as much of the brain as possible without violating SAR limits. We hope to stimulate discussion towards a better understanding and a more quantitative use of fMRI.

Boubela, Roland N.; Kalcher, Klaudius; Nasel, Christian; Moser, Ewald

2014-02-01

61

BOLD fMRI signal characteristics of S1- and S2-SSFP at 7 Tesla  

PubMed Central

Object: To compare the BOLD fMRI signal characteristics at in the cortex and on the pial surface for a non-balanced steady-state free precession sequence (nb-SSFP) at 7 T. Materials and Methods: A multi-echo nb-SSFP sequence was used for high resolution fMRI at 7 T. Two S1 (S+) echoes at different echo times were acquired together with an S2 (S?) echo. The primary visual cortex (V1) was examined using a reversing checkerboard paradigm at an isotropic resolution of 0.75 mm, with 35 volumes acquired and a total scan time of 27 min. Results: Significant activation was observed in all subjects for all three acquired echoes. For the S1 signal at the longer TE, the activation induced signal change was about 4% in the cortex and 10% at the cortical surface, while for S2 the corresponding values were 3 and 5%. Conclusion: For both S1 and S2 data, the BOLD signal peaks at the pial surface. The large pial surface signal change in S2 may be caused by dynamic averaging around post-capillary vessels embedded within CSF. This is made possible by the long diffusion times of the pathways contributing to the S2 signal and the relatively high diffusion coefficient of CSF. The results indicate that S2-SSFP might not be a suited alternative to spin-echo for high-resolution fMRI at 7 T. PMID:24659952

Goa, Pal E.; Koopmans, Peter J.; Poser, Benedikt A.; Barth, Markus; Norris, David G.

2014-01-01

62

Sustained Reperfusion after Blockade of Glycoprotein-Receptor-Ib in Focal Cerebral Ischemia: An MRI Study at 17.6 Tesla  

Microsoft Academic Search

BackgroundInhibition of early platelet adhesion by blockade of glycoprotein-IB (GPIb) protects mice from ischemic stroke. To elucidate underlying mechanisms in-vivo, infarct development was followed by ultra-high field MRI at 17.6 Tesla.MethodsCerebral infarction was induced by transient-middle-cerebral-artery-occlusion (tMCAO) for 1 hour in C57\\/BL6 control mice (N = 10) and mice treated with 100 g Fab-fragments of the GPIb blocking antibody p0p\\/B

Mirko Pham; Xavier Helluy; Christoph Kleinschnitz; Peter Kraft; Andreas J. Bartsch; Peter Jakob; Bernhard Nieswandt; Martin Bendszus; Guido Stoll

2011-01-01

63

3 Tesla multiparametric MRI for GTV-definition of Dominant Intraprostatic Lesions in patients with Prostate Cancer - an interobserver variability study  

PubMed Central

Purpose To evaluate the interobserver variability of gross tumor volume (GTV) - delineation of Dominant Intraprostatic Lesions (DIPL) in patients with prostate cancer using published MRI criteria for multiparametric MRI at 3 Tesla by 6 different observers. Material and methods 90 GTV-datasets based on 15 multiparametric MRI sequences (T2w, diffusion weighted (DWI) and dynamic contrast enhanced (DCE)) of 5 patients with prostate cancer were generated for GTV-delineation of DIPL by 6 observers. The reference GTV-dataset was contoured by a radiologist with expertise in diagnostic imaging of prostate cancer using MRI. Subsequent GTV-delineation was performed by 5 radiation oncologists who received teaching of MRI-features of primary prostate cancer before starting contouring session. GTV-datasets were contoured using Oncentra Masterplan and iplan Net. For purposes of comparison GTV-datasets were imported to the Artiview platform (Aquilab), GTV-values and the similarity indices or Kappa indices (KI) were calculated with the postulation that a KI?>?0.7 indicates excellent, a KI > 0.6 to < 0.7 substantial and KI > 0.5 to < 0.6 moderate agreement. Additionally all observers rated difficulties of contouring for each MRI-sequence using a 3 point rating scale (1?=?easy to delineate, 2?=?minor difficulties, 3?=?major difficulties). Results GTV contouring using T2w (KI-T2w?=?0.61) and DCE images (KI-DCE?=?0.63) resulted in substantial agreement. GTV contouring using DWI images resulted in moderate agreement (KI-DWI?=?0.51). KI-T2w and KI-DCE was significantly higher than KI-DWI (p?=?0.01 and p?=?0.003). Degree of difficulty in contouring GTV was significantly lower using T2w and DCE compared to DWI-sequences (both p?Tesla for GTV-definition of DIPL in prostate cancer patients by radiation oncologists with knowledge of MRI features results in substantial agreement compared to an experienced MRI-radiologist, but for radiotherapy purposes higher KI are desirable, strengthen the need for expert surveillance. DWI sequence for GTV delineation was considered as difficult in application. PMID:23875672

2013-01-01

64

TESLA Superconducting Linear TESLA Collaboration  

E-print Network

Chapter 3 TESLA Superconducting Linear Collider TESLA Collaboration 275 #12;276 CHAPTER 3. TESLA LINEAR COLLIDER24-Oct-9615:40:35I-DEASMasterSeries3:Design Database:/home/sass/ideas_work/ideas_linac/TESLA of Technology, Dep. of Mathematics, Otakaari 1, SF-02150 Espoo: E. Somersalo IHEP, 142284 Protvino, Moscow

65

A fast multiparameter MRI approach for acute stroke assessment on a 3T clinical scanner: preliminary results in a non-human primate model with transient ischemic occlusion  

PubMed Central

Many MRI parameters have been explored and demonstrated the capability or potential to evaluate acute stroke injury, providing anatomical, microstructural, functional, or neurochemical information for diagnostic purposes and therapeutic development. However, the application of multiparameter MRI approach is hindered in clinic due to the very limited time window after stroke insult. Parallel imaging technique can accelerate MRI data acquisition dramatically and has been incorporated in modern clinical scanners and increasingly applied for various diagnostic purposes. In the present study, a fast multiparameter MRI approach including structural T1-weighted imaging (T1W), T2-weighted imaging (T2W), diffusion tensor imaging (DTI), T2-mapping, proton magnetic resonance spectroscopy, cerebral blood flow (CBF), and magnetization transfer (MT) imaging, was implemented and optimized for assessing acute stroke injury on a 3T clinical scanner. A macaque model of transient ischemic stroke induced by a minimal interventional approach was utilized for evaluating the multiparameter MRI approach. The preliminary results indicate the surgical procedure successfully induced ischemic occlusion in the cortex and/or subcortex in adult macaque monkeys (n=4). Application of parallel imaging technique substantially reduced the scanning duration of most MRI data acquisitions, allowing for fast and repeated evaluation of acute stroke injury. Hence, the use of the multiparameter MRI approach with up to five quantitative measures can provide significant advantages in preclinical or clinical studies of stroke disease. PMID:24834423

Tong, Frank; Li, Chun-Xia; Yan, Yumei; Nair, Govind; Nagaoka, Tsukasa; Tanaka, Yoji; Zola, Stuart; Howell, Leonard

2014-01-01

66

Validation of Radiocarpal Joint Contact Models Based On Images from a Clinical MRI Scanner  

E-print Network

Due to the severity and continuing escalation in occurrences of degenerative joint diseases, it is vital to establish a means of detection and prevention that could lead to an improvement in quality of life. One such means is MRI-based modeling...

Johnson, Joshua

2008-01-01

67

Is 3-Tesla Gd-EOB-DTPA-Enhanced MRI with Diffusion-Weighted Imaging Superior to 64-Slice Contrast-Enhanced CT for the Diagnosis of Hepatocellular Carcinoma?  

PubMed Central

Objectives To compare 64-slice contrast-enhanced computed tomography (CT) with 3-Tesla magnetic resonance imaging (MRI) using Gd-EOB-DTPA for the diagnosis of hepatocellular carcinoma (HCC) and evaluate the utility of diffusion-weighted imaging (DWI) in this setting. Methods 3-phase-liver-CT was performed in fifty patients (42 male, 8 female) with suspected or proven HCC. The patients were subjected to a 3-Tesla-MRI-examination with Gd-EOB-DTPA and diffusion weighted imaging (DWI) at b-values of 0, 50 and 400 s/mm2. The apparent diffusion coefficient (ADC)-value was determined for each lesion detected in DWI. The histopathological report after resection or biopsy of a lesion served as the gold standard, and a surrogate of follow-up or complementary imaging techniques in combination with clinical and paraclinical parameters was used in unresected lesions. Diagnostic accuracy, sensitivity, specificity, and positive and negative predictive values were evaluated for each technique. Results MRI detected slightly more lesions that were considered suspicious for HCC per patient compared to CT (2.7 versus 2.3, respectively). ADC-measurements in HCC showed notably heterogeneous values with a median of 1.20.510?3 mm2/s (range from 0.070.1 to 3.00.110?3 mm2/s). MRI showed similar diagnostic accuracy, sensitivity, and positive and negative predictive values compared to CT (AUC 0.837, sensitivity 92%, PPV 80% and NPV 90% for MRI vs. AUC 0.798, sensitivity 85%, PPV 79% and NPV 82% for CT; not significant). Specificity was 75% for both techniques. Conclusions Our study did not show a statistically significant difference in detection in detection of HCC between MRI and CT. Gd-EOB-DTPA-enhanced MRI tended to detect more lesions per patient compared to contrast-enhanced CT; therefore, we would recommend this modality as the first-choice imaging method for the detection of HCC and therapeutic decisions. However, contrast-enhanced CT was not inferior in our study, so that it can be a useful image modality for follow-up examinations. PMID:25375778

Maiwald, Bettina; Lobsien, Donald; Kahn, Thomas; Stumpp, Patrick

2014-01-01

68

HR 3 Tesla MRI for the diagnosis of endolymphatic hydrops and differential diagnosis of inner ear tumors--demonstrated by two cases with similar symptoms.  

PubMed

The synchronous appearance of different inner ear pathologies with a nearly equivalent clinical manifestation such as Menire's disease and vestibular schwannoma is very rare but leads to a relevant dilemma concerning therapy options. MRI is the method of choice to detect intralabyrinthine tumors. Since endolymphatic hydrops is considered the morphological equivalent of Menire's disease, magnetic resonance imaging including hT2w-FLAIR sequences 4?h after i.?v. administration of gadolinium-based contrast agents (GBCA) allows the diagnosis and grading of endolymphatic hydrops in vivo synchronous to diagnosis and monitoring of ILT. To this day, only a few cases of intralabyrinthine schwannoma could be shown to appear simultaneously with endolymphatic hydrops by MRI, but to our knowledge the dedicated distinction of endolymphatic space has not been previously demonstrated. The aim of this work was not only to detect the coincidence of endolymphatic hydrops and vestibular schwannoma, but also to differentiate tumor tissue from endolymphatic space by 3 Tesla MRI. This enables therapy options that are originally indicated for Menire's disease. The aim of this work was to describe the feasibility and usefulness of endolymphatic hydrops MRI on intralabyrinthal tumors in a special case of intravestibular schwannoma to demonstrate the high clinical relevance and impact in therapeutic decision-making for the synchronous appearance of endolymphatic hydrops and intralabyrinthine tumors. Therefore, we present a typical case of Menire's disease in contrast to a patient with an intralabyrinthine schwannoma and Menire-like symptoms. PMID:24452492

Homann, G; Fahrendorf, D; Niederstadt, T; Nagelmann, N; Heindel, W; Ltkenhner, B; Bckenfeld, Y; Basel, T; Vieth, V

2014-03-01

69

Safety Implications of High-Field MRI: Actuation of Endogenous Magnetic Iron Oxides in the Human Body  

Microsoft Academic Search

BackgroundMagnetic Resonance Imaging scanners have become ubiquitous in hospitals and high-field systems (greater than 3 Tesla) are becoming increasingly common. In light of recent European Union moves to limit high-field exposure for those working with MRI scanners, we have evaluated the potential for detrimental cellular effects via nanomagnetic actuation of endogenous iron oxides in the body.MethodologyTheoretical models and experimental data

Jon Dobson; Richard Bowtell; Ana Garcia-Prieto; Quentin Pankhurst; Igor Sokolov

2009-01-01

70

Talking about social conflict in the MRI scanner: neural correlates of being empathized with.  

PubMed

This study investigated the emotional effects and neural correlates of being empathized with while speaking about a currently experienced real-life social conflict during fMRI. Specifically, we focused on the effects of cognitive empathy in the form of paraphrasing, a technique regularly used in conflict resolution. 22 participants underwent fMRI while being interviewed on their social conflict and receiving empathic or unempathic responses from the interviewer. Skin conductance response (SCR) and self-report ratings of feeling understood and emotional valence were used to assess emotional responses. Results confirm previous findings indicating that cognitive empathy exerts a positive short-term effect on emotions in social conflict, while at the same time increasing autonomic arousal reflected by SCR. Effects of paraphrasing and unempathic interventions as indicated by self-report ratings varied depending on self-esteem, pre-interview negative affect, and participants' empathy quotient. Empathic responses engaged a fronto-parietal network with activity in the right precentral gyrus (PrG), left middle frontal gyrus (MFG), left inferior parietal gyrus (IPG), and right postcentral gyrus (PoG). Processing unempathic responses involved a fronto-temporal network with clusters peaking in the left inferior frontal gyrus, pars triangularis (IFGTr), and right temporal pole (TP). A specific modeling of feeling misunderstood activated a network consisting of the IFG, left TP, left Heschl gyrus, IFGTr, and right precuneus, extending to several limbic regions, such as the insula, amygdala, putamen, and anterior cingulate cortex/right middle cingulum (ACC/MCC). The results support the effectiveness of a widely used conflict resolution technique, which may also be useful for professionals who regularly deal with and have to de-escalate situations highly charged with negative emotion, e.g. physicians or judges. PMID:24099849

Seehausen, Maria; Kazzer, Philipp; Bajbouj, Malek; Heekeren, Hauke R; Jacobs, Arthur M; Klann-Delius, Gisela; Menninghaus, Winfried; Prehn, Kristin

2014-01-01

71

Exposure to static and time-varying magnetic fields from working in the static magnetic stray fields of MRI scanners: a comprehensive survey in the Netherlands.  

PubMed

Clinical and research staff who work around magnetic resonance imaging (MRI) scanners are exposed to the static magnetic stray fields of these scanners. Although the past decade has seen strong developments in the assessment of occupational exposure to electromagnetic fields from MRI scanners, there is insufficient insight into the exposure variability that characterizes routine MRI work practice. However, this is an essential component of risk assessment and epidemiological studies. This paper describes the results of a measurement survey of shift-based personal exposure to static magnetic fields (SMF) (B) and motion-induced time-varying magnetic fields (dB/dt) among workers at 15 MRI facilities in the Netherlands. With the use of portable magnetic field dosimeters, >400 full-shift and partial shift exposure measurements were collected among various jobs involved in clinical and research MRI. Various full-shift exposure metrics for B and motion-induced dB/dt exposure were calculated from the measurements, including instantaneous peak exposure and time-weighted average (TWA) exposures. We found strong correlations between levels of static (B) and time-varying (dB/dt) exposure (r = 0.88-0.92) and between different metrics (i.e. peak exposure, TWA exposure) to express full-shift exposure (r = 0.69-0.78). On average, participants were exposed to MRI-related SMFs during only 3.7% of their work shift. Average and peak B and dB/dt exposure levels during the work inside the MRI scanner room were highest among technical staff, research staff, and radiographers. Average and peak B exposure levels were lowest among cleaners, while dB/dt levels were lowest among anaesthesiology staff. Although modest exposure variability between workplaces and occupations was observed, variation between individuals of the same occupation was substantial, especially among research staff. This relatively large variability between workers with the same job suggests that exposure classification based solely on job title may not be an optimal grouping strategy for epidemiological purposes. PMID:25139484

Schaap, Kristel; Christopher-De Vries, Yvette; Crozier, Stuart; De Vocht, Frank; Kromhout, Hans

2014-11-01

72

Recording of the event-related potentials during functional MRI at 3.0 Tesla field strength  

Microsoft Academic Search

The feasibility of recording event-related potentials (ERP) dur- ing functional MRI (fMRI) scanning was studied. Using an alter- nating checkerboard stimulus in a blocked presentation, visu- ally evoked potentials were obtained with their expected con- figuration and latencies. A clustered echoplanar imaging protocol was applied to observe the hemodynamic response due to the visual stimulus interleaved with measuring ERPs. Influences

F. Kruggel; C. J. Wiggins; C. S. Herrmann; D. Y. von Cramon

2000-01-01

73

Functional MRI at 1.5 tesla: A comparison of the blood oxygenation level-dependent signal and electrophysiology  

Microsoft Academic Search

ntil recently, noninvasive techniques used to image the human brain and its activity were not widely accessible. However, in the past few years, procedures such as functional MRI (fMRI) have become readily available and are used in a wide range of disciplines including Radiology, Psychology, Psy- chiatry, Neurology, Neurosurgery, and Neuroscience. The in- vestigations undertaken by different groups are diverse

Elizabeth A. Disbrow; Daniel A. Slutsky; Timothy P. L. Roberts; Leah A. Krubitzer

2000-01-01

74

1.5 Tesla MRI-Conditional 12-lead ECG for MR Imaging and Intra-MR Intervention  

PubMed Central

Propose High-fidelity 12-lead Electrocardiogram (ECG) is important for physiological monitoring of patients during MR-guided intervention and cardiac MR imaging. Issues in obtaining non-corrupted ECGs inside MRI include a superimposed Magneto-Hydro-Dynamic (MHD) voltage, gradient-switching induced-voltages, and radiofrequency (RF) heating. These problems increase with magnetic field. We intended to develop and clinically validate a 1.5T MRI-conditional 12-lead ECG system. Methods The system was constructed, including transmission-lines to reduce radio-frequency induction, and switching-circuits to remove induced voltages. Adaptive filters, trained by 12-lead measurements outside MRI and in two orientations inside MRI, were used to remove MHD. The system was tested on ten (one exercising) volunteers and four arrhythmia patients. Results Switching circuits removed most imaging-induced voltages (residual noise <3% of the R-wave). MHD removal provided intra-MRI ECGs that varied by <3.8% from those outside the MRI, preserving the true ST segment. In premature-ventricular-contraction (PVC) patients, clean ECGs separated PVC and sinus-rhythm beats. Measured heating was <1.5 C0. The system reliably acquired multiphase (SSFP) wall-motion-cine and phase-contrast-cine scans, including in subjects where 4-lead gating failed. The system required a minimum TR of 4ms to allow robust ECG processing. Conclusion High-fidelity intra-MRI 12-lead ECG is possible. PMID:23580148

Tse, Zion Tsz Ho; Dumoulin, Charles L.; Clifford, Gari D.; Schweitzer, Jeff; Qin, Lei; Oster, Julien; Jerosch-Herold, Michael; Kwong, Raymond Y.; Michaud, Gregory; Stevenson, William G.; Schmidt, Ehud J.

2013-01-01

75

Detection power, temporal response, and spatial resolution of IRON fMRI in awake, behaving monkeys at 3 Tesla  

E-print Network

The main goal of this thesis was to systematically characterize the detection sensitivity, temporal response, and spatial resolution of IRON contrast for fMRI within the awake, behaving monkey. Understanding these issues ...

Leite, Francisca Maria Pais Horta

2007-01-01

76

Dynamic contrast-enhanced MRI in ovarian cancer: Initial experience at 3 tesla in primary and metastatic disease.  

PubMed

The aim of this study was to develop and demonstrate a methodology for dynamic contrast-enhanced MRI at 3 T in patients with advanced ovarian cancer and to report the results from pharmacokinetic modeling of the data. Nineteen patients with suspected advanced ovarian carcinoma (FIGO stage 3 or higher) were enrolled in this prospective study. Up to three marker lesions were identified: primary ovarian mass, omental ''cake'', and peritoneal deposits. Dynamic contrast-enhanced MRI was performed using a three-dimensional T(1)-weighted gradient-echo acquisition with a temporal resolution of 1.6 sec, following intravenous administration of 0.1 mmol/kg gadobutrol. Precontrast T(1) mapping, using an inversion-recovery fast gradient-echo sequence, was also performed. Imaging was completed in 18/19 patients, although two were subsequently excluded based on pathology results. Pharmacokinetic modeling of the data was performed according to the extended Kety model, using an arterial input function formed by concatenation of the Fritz-Hansen and Weinmann curves. No statistically significant differences were found between the results for the three marker lesions. In the future, this work will allow kinetic modeling results from ovarian dynamic contrast-enhanced MRI to be correlated with response to treatment. The high temporal resolution allows good characterization of the rapid contrast agent uptake in these vascular tumors. PMID:20373405

Priest, Andrew N; Gill, Andrew B; Kataoka, Masako; McLean, Mary A; Joubert, Ilse; Graves, Martin J; Griffiths, John R; Crawford, Robin A F; Earl, Helena; Brenton, James D; Lomas, David J; Sala, Evis

2010-04-01

77

TESLA Report 1998-28 TESLA Report 1998-28  

E-print Network

TESLA Report 1998-28 #12;TESLA Report 1998-28 #12;TESLA Report 1998-28TESLA Report 1998-28TESLA Report 1998-28 Page 3 TESLA Report 1998-28 Page 1 #12;TESLA Report 1998-28TESLA Report 1998-28TESLA Report 1998-28 Page 4 TESLA Report 1998-28 Page 2 #12;TESLA Report 1998-28TESLA Report 1998-28TESLA

78

Spin Echo functional MRI in bilateral auditory cortices at 7 Tesla: an application of B1 shimming  

PubMed Central

Ultra high fields (UHF) permit unprecedented explorations of functional organizations and insight into basic neuronal processes. Increases in the signal and contrast to noise ratios have allowed increases in the spatial resolution of T *2 weighted gradient echo (GE) echo planar imaging (EPI). Furthermore, while the use of T2 weighted imaging methods at UHF (e.g. spin echo (SE) EPI, gradient and spin echo (GRASE) EPI) can also permit higher resolution images, they in addition allow for increased spatial specificity of functional responses, permitting the in-vivo study of functional organizations down to the columnar level of the cortex. The study of the visual cortex has, thus far, benefitted the most from higher resolution T2 weighted studies as achieving the required transmit B1 magnitude at 7T is more challenging in other brain regions, such as the auditory cortex. As such, auditory fMRI studies at UHF have been limited to T2* weighted GE sequences. Recent advances in multi-channel RF transmission (e.g. B1 shimming) have enabled procedures to efficiently address deficiencies in transmit B1 profiles. However, these techniques, shown to be advantageous in anatomical imaging at UHF, are not generally utilized to facilitate T2 weighted fMRI studies. Here we investigate the feasibility of applying B1 shimming to achieve efficient RF transmission in human auditory cortex. We demonstrate that, with B1 shimming, functional responses to simple tones and to complex sounds (i.e. voices, speech, animal cries, tools and nature) can be efficiently measured with T2 weighted SE-EPI in bilateral human auditory cortex at 7T without exceeding specific absorption rate (SAR) limits. PMID:22917678

De Martino, Federico; Schmitter, Sebastian; Moerel, Michelle; Tian, Jinfeng; Ugurbil, Kamil; Formisano, Elia; Yacoub, Essa; van de Moortele, Pierre-Francois

2012-01-01

79

In vivo detection of microscopic anisotropy using quadruple pulsed-field gradient (qPFG) diffusion MRI on a clinical scanner.  

PubMed

We report our design and implementation of a quadruple pulsed-field gradient (qPFG) diffusion MRI pulse sequence on a whole-body clinical scanner and demonstrate its ability to non-invasively detect restriction-induced microscopic anisotropy in human brain tissue. The microstructural information measured using qPFG diffusion MRI in white matter complements that provided by diffusion tensor imaging (DTI) and exclusively characterizes diffusion of water trapped in microscopic compartments with unique measures of average cell geometry. We describe the effect of white matter fiber orientation on the expected MR signal and highlight the importance of incorporating such information in the axon diameter measurement using a suitable mathematical framework. Integration of qPFG diffusion-weighted images (DWI) with fiber orientations measured using high-resolution DTI allows the estimation of average axon diameters in the corpus callosum of healthy human volunteers. Maps of inter-hemispheric average axon diameters reveal an anterior-posterior variation in good topographical agreement with anatomical measurements reported in previous post-mortem studies. With further technical refinements and additional clinical validation, qPFG diffusion MRI could provide a quantitative whole-brain histological assessment of white and gray matter, enabling a wide range of neuroimaging applications for improved diagnosis of neurodegenerative pathologies, monitoring neurodevelopmental processes, and mapping brain connectivity. PMID:22939872

Avram, Alexandru V; zarslan, Evren; Sarlls, Joelle E; Basser, Peter J

2013-01-01

80

TESLA Report 1997-22 TESLA Report 1997-22  

E-print Network

TESLA Report 1997-22 #12;TESLA Report 1997-22 #12;TESLA Report 1997-22 #12;TESLA Report 1997-22 #12;TESLA Report 1997-22 #12;TESLA Report 1997-22 #12;TESLA Report 1997-22 #12;TESLA Report 1997-22 #12;TESLA Report 1997-22 #12;TESLA Report 1997-22 #12;TESLA Report 1997-22 #12;TESLA Report 1997-22 #12

81

Association between in-scanner head motion with cerebral white matter microstructure: a multiband diffusion-weighted MRI study  

PubMed Central

Diffusion-weighted Magnetic Resonance Imaging (DW-MRI) has emerged as the most popular neuroimaging technique used to depict the biological microstructural properties of human brain white matter. However, like other MRI techniques, traditional DW-MRI data remains subject to head motion artifacts during scanning. For example, previous studies have indicated that, with traditional DW-MRI data, head motion artifacts significantly affect the evaluation of diffusion metrics. Actually, DW-MRI data scanned with higher sampling rate are important for accurately evaluating diffusion metrics because it allows for full-brain coverage through the acquisition of multiple slices simultaneously and more gradient directions. Here, we employed a publicly available multiband DW-MRI dataset to investigate the association between motion and diffusion metrics with the standard pipeline, tract-based spatial statistics (TBSS). The diffusion metrics used in this study included not only the commonly used metrics (i.e., FA and MD) in DW-MRI studies, but also newly proposed inter-voxel metric, local diffusion homogeneity (LDH). We found that the motion effects in FA and MD seems to be mitigated to some extent, but the effect on MD still exists. Furthermore, the effect in LDH is much more pronounced. These results indicate that researchers shall be cautious when conducting data analysis and interpretation. Finally, the motion-diffusion association is discussed. PMID:24795856

2014-01-01

82

[Image distortion and artifacts caused by the use of a titanium aneurism clip in 1.5 tesla- and 3 tesla-magnetic resonance imaging: effect on 60cobalt stereotactic radiosurgery treatment planning].  

PubMed

In gamma knife stereotactic radiosurgery (GKSRS) treatment planning, 1.5 tesla (T)-magnetic resonance imaging (MRI) is normally used to identify the target lesion. Image artifacts and distortion arise in MRI if a titanium clip is surgically implanted in the brain to treat cerebral aneurysm. 3-T MRI scanners, which are increasingly being adopted, provide imaging of anatomic structures with better clinical usefulness than 1.5-T MRI machines. We investigated signal defects and image distortions both close to and more distant from the titanium clip in 1.5-T and 3-T MRI. Two kinds of phantoms were scanned using 1.5-T and 3-T MRI. Acquisitions with and without the clip were performed under the same scan parameters. No difference was observed between 1.5 T and 3 T in local decrease of signal intensity; however, image distortion was observed at 20 mm from the clip in 3 T. Over the whole region, the distortions caused by the clip were less than 0.3 mm and 1.6 mm under 1.5-T and 3-T MRI, respectively. The geometric accuracy of 1.5-T MRI was better than 3-T MRI and thus better for GKSRS treatment planning. 3-T MRI, however, appears less suitable for use in treatment planning. PMID:24953318

Nakazawa, Hisato; Yamamuro, Osamu; Uchiyama, Yukio; Komori, Masataka

2014-06-01

83

7 Tesla Magnetic Resonance Imaging to Detect Cortical Pathology in Multiple Sclerosis  

PubMed Central

Background Neocortical lesions (NLs) are an important pathological component of multiple sclerosis (MS), but their visualization by magnetic resonance imaging (MRI) remains challenging. Objectives We aimed at assessing the sensitivity of multi echo gradient echo (ME-GRE) T2*-weighted MRI at 7.0 Tesla in depicting NLs compared to myelin and iron staining. Methods Samples from two MS patients were imaged post mortem using a whole body 7T MRI scanner with a 24-channel receive-only array. Isotropic 200 micron resolution images with varying T2* weighting were reconstructed from the ME-GRE data and converted into R2* maps. Immunohistochemical staining for myelin (proteolipid protein, PLP) and diaminobenzidine-enhanced Turnbull blue staining for iron were performed. Results Prospective and retrospective sensitivities of MRI for the detection of NLs were 48% and 67% respectively. We observed MRI maps detecting only a small portion of 20 subpial NLs extending over large cortical areas on PLP stainings. No MRI signal changes suggestive of iron accumulation in NLs were observed. Conversely, R2* maps indicated iron loss in NLs, which was confirmed by histological quantification. Conclusions High-resolution post mortem imaging using R2* and magnitude maps permits detection of focal NLs. However, disclosing extensive subpial demyelination with MRI remains challenging. PMID:25303286

van Gelderen, Peter; Merkle, Hellmuth; Chen, Christina; Lassmann, Hans; Duyn, Jeff H.; Bagnato, Francesca

2014-01-01

84

Functional diffusion tensor imaging at 3 Tesla  

PubMed Central

In a previous study we reported on a non-invasive functional diffusion tensor imaging (fDTI) method to measure neuronal signals directly from subtle changes in fractional anisotropy along white matter tracts. We hypothesized that these fractional anisotropy changes relate to morphological changes of glial cells induced by axonal activity. In the present study we set out to replicate the results of the previous study with an improved fDTI scan acquisition scheme. A group of twelve healthy human participants were scanned on a 3 Tesla MRI scanner. Activation was revealed in the contralateral thalamo-cortical tract and optic radiations during tactile and visual stimulation, respectively. Mean percent signal change in FA was 3.47% for the tactile task and 3.79% for the visual task, while for the MD the mean percent signal change was only -0.10 and -0.09%. The results support the notion of different response functions for tactile and visual stimuli. With this study we successfully replicated our previous findings using the same types of stimuli but on a different group of healthy participants and at different field-strength. The successful replication of our first fDTI results suggests that the non-invasive fDTI method is robust enough to study the functional neural networks in the human brain within a practically feasible time period. PMID:24409133

Mandl, Rene C. W.; Schnack, Hugo G.; Zwiers, Marcel P.; Kahn, Rene S.; Hulshoff Pol, Hilleke E.

2013-01-01

85

Haptic fMRI: combining functional neuroimaging with haptics for studying the brain's motor control representation.  

PubMed

A challenging problem in motor control neuroimaging studies is the inability to perform complex human motor tasks given the Magnetic Resonance Imaging (MRI) scanner's disruptive magnetic fields and confined workspace. In this paper, we propose a novel experimental platform that combines Functional MRI (fMRI) neuroimaging, haptic virtual simulation environments, and an fMRI-compatible haptic device for real-time haptic interaction across the scanner workspace (above torso ? .65.40.20m(3)). We implement this Haptic fMRI platform with a novel haptic device, the Haptic fMRI Interface (HFI), and demonstrate its suitability for motor neuroimaging studies. HFI has three degrees-of-freedom (DOF), uses electromagnetic motors to enable high-fidelity haptic rendering (>350Hz), integrates radio frequency (RF) shields to prevent electromagnetic interference with fMRI (temporal SNR >100), and is kinematically designed to minimize currents induced by the MRI scanner's magnetic field during motor displacement (<2cm). HFI possesses uniform inertial and force transmission properties across the workspace, and has low friction (.05-.30N). HFI's RF noise levels, in addition, are within a 3 Tesla fMRI scanner's baseline noise variation (?.85.1%). Finally, HFI is haptically transparent and does not interfere with human motor tasks (tested for .4m reaches). By allowing fMRI experiments involving complex three-dimensional manipulation with haptic interaction, Haptic fMRI enables-for the first time-non-invasive neuroscience experiments involving interactive motor tasks, object manipulation, tactile perception, and visuo-motor integration. PMID:24110643

Menon, Samir; Brantner, Gerald; Aholt, Chris; Kay, Kendrick; Khatib, Oussama

2013-01-01

86

TESLA Polarimeters  

E-print Network

We describe a study of high-energy Compton beam polarimeters for the future e+e- linear collider machine TESLA. A segment of the beam delivery system has been identified, which is aligned with the e+e- collision axis and which has a suitable configuration for high-quality beam polarization measurements. The laser envisaged for the polarimeter is similar to an existing facility at DESY. It delivers very short pulses in the 10 ps, 10-100uJ regime and operates with a pattern that matches the pulse and bunch structure of TESLA. This will permit very fast and accurate measurements and an expeditious tune-up of the spin manipulators at the low-energy end of the linac. Electron detection in the multi-event regime will be the principle operating mode of the polarimeter. Other possible operating modes include photon detection and single-event detection for calibration purposes. We expect an overall precision of dP/P=0.5% for the measurement of the beam polarization.

V. Gharibyan; N. Meyners; K. P. Schuler

2003-10-22

87

Programmable hydrocephalus shunt which cannot be unwillingly re-adjusted even in 3T MRI magnet  

E-print Network

BioMed Central Page 1 of 1 (page number not for citation purposes) Cerebrospinal Fluid Research Open AccessPoster presentation Programmable hydrocephalus shunt which cannot be unwillingly re-adjusted even in 3T MRI magnet David Allin, Marek... - ming proved to be easy and reliable. Strong magnetic fields (3Tesla MRI scanner) are not able to change the pro- gramming of the valve. Conclusion From the point of view of its hydrodynamic performance, the ProGAV shunt is reliable, differential...

2006-12-21

88

A high-field 3He Metastability Exchange Optical Pumping polarizer operating in a 1.5 T medical scanner for lung MRI  

E-print Network

After being hyperpolarized using the technique of Metastability Exchange Optical Pumping (MEOP), 3He can be used as a contrast agent for lung magnetic resonance imaging (MRI). MEOP is usually performed at low magnetic field (~ 1 mT) and low pressure (~ 1 mbar), which results in a low magnetization production rate. A delicate polarization-preserving step of compression is also required. It was demonstrated in sealed cells that high nuclear polarization values can be obtained at higher pressures with MEOP, if performed at high magnetic field (non-standard conditions). In this work the feasibility of building a high-field polarizer that operates within a commercial 1.5 T scanner was evaluated. Preliminary measurements of nuclear polarization with sealed cells filled at different 3He gas pressures (1.33 to 267 mbar) were performed. The use of an annular shape for the laser beam increased by 25 % the achievable nuclear polarization equilibrium value (Meq) at 32 and 67 mbar as compared to a Gaussian beam shape. Meq...

Collier, G; Wojna, A; G?owacz, B; Suchanek, M; Olejniczak, Z; Dohnalik, T

2013-01-01

89

Tumor Volume Changes on 1.5 Tesla Endorectal MRI During Neoadjuvant Androgen Suppression Therapy for Higher-Risk Prostate Cancer and Recurrence in Men Treated Using Radiation Therapy Results of the Phase II CALGB 9682 Study  

SciTech Connect

Purpose: We prospectively determined whether the change in tumor volume (TV) during 2 months of neoadjuvant androgen suppression therapy (nAST) measured using conventional 1.5 Tesla endorectal magnetic resonance imaging (eMRI) was associated with the risk of recurrence after radiation (RT) and 6 months of AST. Patients and Methods: Between 1997 and 2001, 180 men with clinical stage T1c-T3cN0M0 adenocarcinoma of the prostate were registered. Fifteen were found to be ineligible and the institutional MR radiologist could not assess the TV in 32, leaving 133 for analysis. Multivariable Cox regression analysis was used to assess whether a significant association existed between eMRI-defined TV progression during nAST and time to recurrence adjusting for prostate-specific antigen (PSA) level, Gleason score (8 to 10 or 7 vs. 6 or less) and stage (T3 vs. T1-2). Results: After a median follow up of 6.7 years and adjusting for known prognostic factors, there was a significant increase in the risk of PSA failure (HR, 2.3 [95% CI, 1.1-4.5; p = 0.025) in men with eMRI-defined TV progression during nAST. Specifically, adjusted estimates of PSA failure were significantly higher (p = 0.032) in men with, compared with men without, eMRI-defined TV progression reaching 38% vs. 19%, respectively, by 5 years. Conclusion: Eradicating intraprostatic hormone refractory prostate cancer (HRPC) by maximizing local control and randomized trials assessing whether survival is improved when agents active against HRPC are combined with maximal local therapy are needed in men who progress based on eMRI during nAST.

D'Amico, Anthony V. [Brigham and Women's Hospital and Dana-Farber Cancer Institute, Boston, MA (United States)], E-mail: adamico@partners.org; Halabi, Susan [CALGB Statistical Center, Duke University Medical Center, Durham, NC (United States); Tempany, Clare; Titelbaum, David [Brigham and Women's Hospital and Dana-Farber Cancer Institute, Boston, MA (United States); Philips, George K. [University of Vermont Cancer Center, Burlington, VT (United States); Loffredo, Marian; McMahon, Elizabeth [Brigham and Women's Hospital and Dana-Farber Cancer Institute, Boston, MA (United States); Sanford, Ben [CALGB Statistical Center, Duke University Medical Center, Durham, NC (United States); Vogelzang, Nicholas J. [Las Vegas Cancer Center, Las Vegas, NV (United States); Small, Eric J. [University of California at San Francisco, San Francisco, CA (United States)

2008-05-01

90

Can the Neural Basis of Repression Be Studied in the MRI Scanner? New Insights from Two Free Association Paradigms  

PubMed Central

Background The psychodynamic theory of repression suggests that experiences which are related to internal conflicts become unconscious. Previous attempts to investigate repression experimentally were based on voluntary, intentional suppression of stimulus material. Unconscious repression of conflict-related material is arguably due to different processes, but has never been studied with neuroimaging methods. Methods We used functional magnetic resonance imaging (fMRI) in addition with skin conductance recordings during two free association paradigms to identify the neural mechanisms underlying forgetting of freely associated words according to repression theory. Results In the first experiment, free association to subsequently forgotten words was accompanied by increases in skin conductance responses (SCRs) and reaction times (RTs), indicating autonomic arousal, and by activation of the anterior cingulate cortex. These findings are consistent with the hypothesis that these associations were repressed because they elicited internal conflicts. To test this idea more directly, we conducted a second experiment in which participants freely associated to conflict-related sentences. Indeed, these associations were more likely to be forgotten than associations to not conflict-related sentences and were accompanied by increases in SCRs and RTs. Furthermore, we observed enhanced activation of the anterior cingulate cortex and deactivation of hippocampus and parahippocampal cortex during association to conflict-related sentences. Conclusions These two experiments demonstrate that high autonomic arousal during free association predicts subsequent memory failure, accompanied by increased activation of conflict-related and deactivation of memory-related brain regions. These results are consistent with the hypothesis that during repression, explicit memory systems are down-regulated by the anterior cingulate cortex. PMID:23638050

Kessler, Henrik; Do Lam, Anne T. A.; Fell, Juergen; Schmidt, Anna-Christine; Axmacher, Nikolai

2013-01-01

91

Simultaneous Measurement of Kidney Function by Dynamic Contrast Enhanced MRI and FITC-Sinistrin Clearance in Rats at 3 Tesla: Initial Results  

PubMed Central

Glomerular filtration rate (GFR) is an essential parameter of kidney function which can be measured by dynamic contrast enhanced magnetic resonance imaging (MRI-GFR) and transcutaneous approaches based on fluorescent tracer molecules (optical-GFR). In an initial study comparing both techniques in separate measurements on the same animal, the correlation of the obtained GFR was poor. The goal of this study was to investigate if a simultaneous measurement was feasible and if thereby, the discrepancies in MRI-GFR and optical-GFR could be reduced. For the experiments healthy and unilateral nephrectomised (UNX) Sprague Dawley (SD) rats were used. The miniaturized fluorescent sensor was fixed on the depilated back of an anesthetized rat. A bolus of 5 mg/100 g b.w. of FITC-sinistrin was intravenously injected. For dynamic contrast enhanced perfusion imaging (DCE-MRI) a 3D time-resolved angiography with stochastic trajectories (TWIST) sequence was used. By means of a one compartment model the excretion half-life (t1/2) of FITC-sinistrin was calculated and converted into GFR. GFR from DCE-MRI was calculated by fitting pixel-wise a two compartment renal filtration model. Mean cortical GFR and GFR by FITC-sinistrin were compared by Bland-Altman plots and pair-wise t-test. Results show that a simultaneous GFR measurement using both techniques is feasible. Mean optical-GFR was 4.342.22 ml/min (healthy SD rats) and 2.340.90 ml/min (UNX rats) whereas MRI-GFR was 2.100.64 ml/min (SD rats) and 1.170.38 ml/min (UNX rats). Differences between healthy and UNX rats were significant (p<0.05) and almost equal percentage difference (46.1% and 44.3%) in mean GFR were assessed with both techniques. Overall mean optical-GFR values were approximately twice as high compared to MRI-GFR values. However, compared to a previous study, our results showed a higher agreement. In conclusion, the possibility to use the transcutaneous method in MRI may have a huge impact in improving and validating MRI methods for GFR assessment in animal models. PMID:24260332

Backer, Sandra; Neudecker, Sabine; Gretz, Norbert; Schad, Lothar R.

2013-01-01

92

Real-time magnetic resonance imagingguided radiofrequency atrial ablation and visualization of lesion formation at 3 Tesla  

E-print Network

of lesion formation at 3 Tesla Gaston R. Vergara, MD,* Sathya Vijayakumar, MS,* Eugene G. Kholmovski, Ph. In this study, we report a novel 3-Tesla RT -RI based porcine RF ablation model and visuali- zation of lesion-Tesla RT MRI-based catheter ablation and lesion visualization system. METHODS RF energy was delivered

Utah, University of

93

Non-Enhanced MR Imaging of Cerebral Aneurysms: 7 Tesla versus 1.5 Tesla  

PubMed Central

Purpose To prospectively evaluate 7 Tesla time-of-flight (TOF) magnetic resonance angiography (MRA) in comparison to 1.5 Tesla TOF MRA and 7 Tesla non-contrast enhanced magnetization-prepared rapid acquisition gradient-echo (MPRAGE) for delineation of unruptured intracranial aneurysms (UIA). Material and Methods Sixteen neurosurgical patients (male n?=?5, female n?=?11) with single or multiple UIA were enrolled in this trial. All patients were accordingly examined at 7 Tesla and 1.5 Tesla MRI utilizing dedicated head coils. The following sequences were obtained: 7 Tesla TOF MRA, 1.5 Tesla TOF MRA and 7 Tesla non-contrast enhanced MPRAGE. Image analysis was performed by two radiologists with regard to delineation of aneurysm features (dome, neck, parent vessel), presence of artifacts, vessel-tissue-contrast and overall image quality. Interobserver accordance and intermethod comparisons were calculated by kappa coefficient and Lin's concordance correlation coefficient. Results A total of 20 intracranial aneurysms were detected in 16 patients, with two patients showing multiple aneurysms (n?=?2, n?=?4). Out of 20 intracranial aneurysms, 14 aneurysms were located in the anterior circulation and 6 aneurysms in the posterior circulation. 7 Tesla MPRAGE imaging was superior over 1.5 and 7 Tesla TOF MRA in the assessment of all considered aneurysm and image quality features (e.g. image quality: mean MPRAGE7T: 5.0; mean TOF7T: 4.3; mean TOF1.5T: 4.3). Ratings for 7 Tesla TOF MRA were equal or higher over 1.5 Tesla TOF MRA for all assessed features except for artifact delineation (mean TOF7T: 4.3; mean TOF1.5T 4.4). Interobserver accordance was good to excellent for most ratings. Conclusion 7 Tesla MPRAGE imaging demonstrated its superiority in the detection and assessment of UIA as well as overall imaging features, offering excellent interobserver accordance and highest scores for all ratings. Hence, it may bear the potential to serve as a high-quality diagnostic tool for pretherapeutic assessment and follow-up of untreated UIA. PMID:24400100

Wrede, Karsten H.; Dammann, Philipp; Monninghoff, Christoph; Johst, Soren; Maderwald, Stefan; Sandalcioglu, I. Erol; Muller, Oliver; Ozkan, Neriman; Ladd, Mark E.; Forsting, Michael; Schlamann, Marc U.; Sure, Ulrich; Umutlu, Lale

2014-01-01

94

Beam monitors for TESLA based on diamond strip detectors  

Microsoft Academic Search

For TeV energy superconducting linear accelerator (TESLA), it is foreseen to measure the beam profile with so-called wire scanners. A thin carbon fiber is moved through the beam and the number of scattered secondary particles is measured in correlation to the position of the wire. From this, a beam profile can be calculated as an average over many bunches of

J. Bol; E. Berdermann; W. Deboer; E. Grigoriev; F. Hauler; L. Jungermann

2004-01-01

95

MRI  

MedlinePLUS Videos and Cool Tools

... body. To get the clearest picture, you should lie very still. Because an MRI uses a large magnet instead of x-rays, it is safer than other technologies for looking inside the body. However, because of the magnet, people who have metal of any kind implanted in ...

96

Edison vs. Tesla  

ScienceCinema

As Edison vs. Tesla week heats up at the Energy Department, we are exploring the rivalry between Thomas Edison and Nikola Tesla and how their work is still impacting the way we use energy today. Whether you're on Team Tesla or Team Edison, both inventors were key players in creating things like batteries, power plants and wireless technologies -- all innovations we still use today. And as we move toward a clean energy future, energy efficient lighting, like LED bulbs, and more efficient electric motors not only help us save money on electricity costs but help combat climate change. For this, Tesla and Edison both deserve our recognition.

Hogan, Kathleen; Wallace, Hal; Ivestor, Rob

2014-01-07

97

Edison vs. Tesla  

SciTech Connect

As Edison vs. Tesla week heats up at the Energy Department, we are exploring the rivalry between Thomas Edison and Nikola Tesla and how their work is still impacting the way we use energy today. Whether you're on Team Tesla or Team Edison, both inventors were key players in creating things like batteries, power plants and wireless technologies -- all innovations we still use today. And as we move toward a clean energy future, energy efficient lighting, like LED bulbs, and more efficient electric motors not only help us save money on electricity costs but help combat climate change. For this, Tesla and Edison both deserve our recognition.

Hogan, Kathleen; Wallace, Hal; Ivestor, Rob

2013-11-20

98

Integrating Structural and Functional Imaging for Computer Assisted Detection of Prostate Cancer on Multi-Protocol In Vivo 3 Tesla MRI  

PubMed Central

Screening and detection of prostate cancer (CaP) currently lacks an image-based protocol which is reflected in the high false negative rates currently associated with blinded sextant biopsies. Multi-protocol magnetic resonance imaging (MRI) offers high resolution functional and structural data about internal body structures (such as the prostate). In this paper we present a novel comprehensive computer-aided scheme for CaP detection from high resolution in vivo multi-protocol MRI by integrating functional and structural information obtained via dynamic-contrast enhanced (DCE) and T2-weighted (T2-w) MRI, respectively. Our scheme is fully-automated and comprises (a) prostate segmentation, (b) multimodal image registration, and (c) data representation and multi-classifier modules for information fusion. Following prostate boundary segmentation via an improved active shape model, the DCE/T2-w protocols and the T2-w/ex vivo histological prostatectomy specimens are brought into alignment via a deformable, multi-attribute registration scheme. T2-w/histology alignment allows for the mapping of true CaP extent onto the in vivo MRI, which is used for training and evaluation of a multi-protocol MRI CaP classifier. The meta-classifier used is a random forest constructed by bagging multiple decision tree classifiers, each trained individually on T2-w structural, textural and DCE functional attributes. 3-fold classifier cross validation was performed using a set of 18 images derived from 6 patient datasets on a per-pixel basis. Our results show that the results of CaP detection obtained from integration of T2-w structural textural data and DCE functional data (area under the ROC curve of 0.815) significantly outperforms detection based on either of the individual modalities (0.704 (T2-w) and 0.682 (DCE)). It was also found that a meta-classifier trained directly on integrated T2-w and DCE data (data-level integration) significantly outperformed a decision-level meta-classifier, constructed by combining the classifier outputs from the individual T2-w and DCE channels. PMID:25301989

Viswanath, Satish; Bloch, B. Nicolas; Rosen, Mark; Chappelow, Jonathan; Toth, Robert; Rofsky, Neil; Lenkinski, Robert; Genega, Elisabeth; Kalyanpur, Arjun; Madabhushi, Anant

2014-01-01

99

TESLA-Report 2002-07 TESLA-Report 2002-07  

E-print Network

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100

TESLA-Report 1993-33 TESLA-Report 1993-33  

E-print Network

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TESLA-Report 1995-11 TESLA-Report 1995-11  

E-print Network

#12;TESLA-Report 1995-11 #12;TESLA-Report 1995-11 #12;TESLA-Report 1995-11 #12;TESLA-Report 1995-11 #12;TESLA-Report 1995-11 #12;TESLA-Report 1995-11 #12;TESLA-Report 1995-11 #12;TESLA-Report 1995-11 #12;TESLA-Report 1995-11 #12;TESLA-Report 1995-11 #12;TESLA-Report 1995-11 #12;TESLA-Report 1995

102

In Vivo13C Magnetic Resonance Spectroscopy of Human Brain on a Clinical 3 Tesla Scanner Using [2-13C]Glucose Infusion and Low Power Stochastic Decoupling  

PubMed Central

This study presents the detection of [2-13C]glucose metabolism in the carboxylic/amide region in the human brain, and demonstrates that the cerebral metabolism of [2-13C]glucose can be studied in human subjects in the presence of severe hardware constraints of widely available 3 T clinical scanners and with low power stochastic decoupling. In the carboxylic/amide region of human brain, the primary products of 13C label incorporation from [2-13C]glucose into glutamate, glutamine, aspartate, ?-aminobutyric acid, and N-acetylaspartate were detected. Unlike the commonly used alkanyl region where lipid signals spread over a broad frequency range, the carboxylic carbon signal of lipids was found to be confined to a narrow range centered at 172.5 ppm and present no spectral interference in the absence of lipid suppression. Comparison using phantoms shows that stochastic decoupling is far superior than the commonly used WALTZ sequence at very low decoupling power at 3 T. It was found that glutamine C1 and C5 can be decoupled using stochastic decoupling at 2.2 W although glutamine protons span a frequency range of ?700 Hz. Detailed specific absorption rate analysis was also performed using finite difference time domain numerical simulation. PMID:19526500

Li, Shizhe; Zhang, Yan; Wang, Shumin; Yang, Jehoon; Araneta, Maria Ferraris; Farris, Amanda; Johnson, Christopher; Fox, Stephen; Innis, Robert; Shen, Jun

2009-01-01

103

Physics at TESLA  

E-print Network

The physics at a 500-800 GeV electron positron linear collider, TESLA, is reviewed. The machine parameters that impact directly on the physics are discussed and a few key performance goals for a detector at TESLA are given. Emphasis is placed on precision measurements in the Higgs and top sectors and on extrapolation to high energy scales in the supersymmetric scenario.

Grahame A. Blair

2001-04-25

104

TESLA Report 2003-32 FPGA based TESLA cavity SIMCON  

E-print Network

TESLA Report 2003-32 FPGA based TESLA cavity SIMCON DOOCS server design, implementation of the laboratory solution of the FPGA based TESLA cavity simulator and controller (SIMCON) is presented. The major is a first description of the working DOOCS server for the FPGA based TESLA cavity SIMCON (which is a part

105

Comparison of low-field (0.2 Tesla) and high-field (1.5 Tesla) magnetic resonance imaging of the knee joint  

Microsoft Academic Search

In order to evaluate the reliability of low-field magnetic resonance imaging (MRI), we examined 22 patients using a 0.2-Tesla magnet unit in comparison with a 1.5-Tesla system. The MRI findings were compared with the intraoperative findings. Concerning the diagnosis of meniscal tears, the gradings of both systems differed only in three cases. The specificity was 97% (both systems), the sensitivity

B. Kladny; K. Glckert; B. Swoboda; W. Beyer; G. Weseloh

1995-01-01

106

TESLA FEL Report 1996-07 TESLA FEL Report 1996-07  

E-print Network

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TESLA FEL-Report 1995-02 TESLA FEL-Report 1995-02  

E-print Network

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TESLA FEL-Report 1995-04 TESLA FEL-Report 1995-04  

E-print Network

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TESLA FEL-Report 1996-10 TESLA FEL-Report 1996-10  

E-print Network

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TESLA FEL-Report 2000-02 TESLA FEL-Report 2000-02  

E-print Network

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TESLA FEL-Report 1997-02 TESLA FEL-Report 1997-02  

E-print Network

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TESLA FEL-Report 1999-03 TESLA FEL-Report 1999-03  

E-print Network

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TESLA FEL Report 1996-06 TESLA FEL Report 1996-06  

E-print Network

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TESLA FEL-Report 1996-16 TESLA FEL-Report 1996-16  

E-print Network

#12;TESLA FEL-Report 1996-16 #12;TESLA FEL-Report 1996-16 #12;TESLA FEL-Report 1996-16 #12;TESLA FEL-Report 1996-16 #12;TESLA FEL-Report 1996-16 #12;TESLA FEL-Report 1996-16 #12;TESLA FEL-Report 1996-16 #12;TESLA FEL-Report 1996-16 #12;TESLA FEL-Report 1996-16 #12;TESLA FEL-Report 1996-16 #12;TESLA FEL

115

TESLA FEL-Report 1996-13 TESLA FEL-Report 1996-13  

E-print Network

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116

Superconducting TESLA cavities  

Microsoft Academic Search

The conceptional design of the proposed linear electron-positron collider TESLA is based on 9-cell 1.3 GHz superconducting niobium cavities with an accelerating gradient of Eacc>=25 MV\\/m at a quality factor Q0>=5109. The design goal for the cavities of the TESLA Test Facility (TTF) linac was set to the more moderate value of Eacc>=15 MV\\/m. In a first series of 27

B. Aune; R. Bandelmann; D. Bloess; B. Bonin; A. Bosotti; M. Champion; C. Crawford; G. Deppe; B. Dwersteg; D. A. Edwards; H. T. Edwards; M. Ferrario; M. Fouaidy; P.-D. Gall; A. Gamp; A. Gssel; J. Graber; D. Hubert; M. Hning; M. Juillard; T. Junquera; H. Kaiser; G. Kreps; M. Kuchnir; R. Lange; M. Leenen; M. Liepe; L. Lilje; A. Matheisen; W.-D. Mller; A. Mosnier; H. Padamsee; C. Pagani; M. Pekeler; H.-B. Peters; O. Peters; D. Proch; K. Rehlich; D. Reschke; H. Safa; T. Schilcher; P. Schmser; J. Sekutowicz; S. Simrock; W. Singer; M. Tigner; D. Trines; K. Twarowski; G. Weichert; J. Weisend; J. Wojtkiewicz; S. Wolff; K. Zapfe

2000-01-01

117

Choroidal Blood Flow Decreases with Age: An MRI Study  

PubMed Central

Purpose To verify that a visual fixation protocol with cued eye blinks achieves sufficient stability for magnetic resonance imaging (MRI) blood-flow measurements and to determine if choroidal blood flow (ChBF) changes with age in humans. Methods The visual fixation stability achievable during an MRI scan was measured in five normal subjects using an eye-tracking camera outside the MRI scanner. Subjects were instructed to blink immediately after recorded MRI sound cues but to otherwise maintain stable visual fixation on a small target. Using this fixation protocol, ChBF was measured with MRI using a 3 Tesla clinical scanner in 17 normal subjects (2468 years old). Arterial and intraocular pressures (IOP) were measured to calculate perfusion pressure in the same subjects. Results The mean temporal fluctuations (standard deviation) of the horizontal and vertical displacements were 29 9 ?m and 38 11 ?m within individual fixation periods, and 50 34 ?m and 48 19 ?m across different fixation periods. The absolute displacements were 67 31 ?m and 81 26 ?m. ChBF was negatively correlated with age (R =?0.7, p = 0.003), declining 2.7 ml/100 ml/min per year. There were no significant correlations between ChBF versus perfusion pressure, arterial pressure, or IOP. There were also no significant correlations between age versus perfusion pressure, arterial pressure, or IOP. Multiple regression analysis indicated that age was the only measured independent variable that was significantly correlated with ChBF (p = 0.03). Conclusions The visual fixation protocol with cued eye blinks was effective in achieving sufficient stability for MRI measurements. ChBF had a significant negative correlation with age. PMID:24655028

San Emeterio Nateras, Oscar; Harrison, Joseph M.; Muir, Eric R.; Zhang, Yi; Peng, Qi; Chalfin, Steven; Gutierrez, Juan E.; Johnson, Daniel A.; Kiel, Jeffrey W.; Duong, Timothy Q.

2014-01-01

118

TESLA REPORT 2006-02 TESLA THESIS 2006-003  

E-print Network

TESLA REPORT 2006-02 TESLA THESIS 2006-003 WARSAW UNIVERSITY OF TECHNOLOGY Faculty of Electronics and Information Technology Institute of Electronic Systems Krzysztof Kamil Korzunowicz 185691 Bachelor of Science, quickly and cheaply evaluate the doses of neutrons and gammas in the Tesla Test Facility (TTF) tunnel

119

In-bore setup and Software for 3T MRI-guided Transperineal Prostate Biopsy  

PubMed Central

MRI-guided prostate biopsy in conventional closed-bore scanners requires transferring the patient outside the bore during needle insertion due to the constrained in-bore space, causing a safety hazard and limiting image feedback. To address this issue, we present our custom-made in-bore setup and software to support MRI-guided transperineal prostate biopsy in a wide-bore 3 Tesla (T) MRI scanner. The setup consists of a specially designed tabletop and a needle-guiding template with Z-frame that give a physician access to the perineum of the patient at the imaging position and allow performance of MRI-guided transperineal biopsy without moving the patient out of the scanner. The software and Z-frame allow registration of the template, target planning, and biopsy guidance. Initially, we performed phantom experiments to assess the accuracy of template registration and needle placement in a controlled environment. Subsequently, we embarked on our clinical trial (N = 10). The phantom experiments showed that the translational errors of the template registration along the right-left (RP) and anterior-posterior (AP) axes were 1.1 0.8 mm and 1.4 1.1 mm respectively, while the rotational errors around the RL, AP, and superior-inferior axes were 0.8 1.0 degrees, 1.7 1.6 degrees, and 0.0 0.0 degrees respectively. The 2D root-mean-square (RMS) needle placement error was 3.0 mm. The clinical biopsy procedures were safely carried out in all ten clinical cases with a needle placement error of 5.4 mm (2D RMS). In conclusion, transperineal prostate biopsy in a wide-bore 3T scanner is feasible using our custom-made tabletop set up and software, which supports manual needle placement without moving the patient out of the magnet. PMID:22951350

Tokuda, Junichi; Tuncali, Kemal; Iordachita, Iulian; Song, Sang-Eun; Fedorov, Andriy; Oguro, Sota; Lasso, Andras; Fennessy, Fiona M; Tempany, Clare M; Hata, Nobuhiko

2012-01-01

120

The TESLA free electron laser  

Microsoft Academic Search

The TESLA Free Electron Laser (FEL) makes use of the high electron beam quality that can be provided by the su- perconducting TESLA linac to drive a single pass FEL at wavelengths far below the visible. To reach a wavelength of 6 nanometers, the TESLA Test Facility (TTF) currently under construction at DESY will be extended to 1 GeV beam

J. Rossbach

1998-01-01

121

The TESLA free electron laser  

Microsoft Academic Search

The TESLA free Electron Laser (FEL) makes use of the high electron beam quality that can be provided by the superconducting TESLA linac to drive a single pass FEL at wavelengths far below the visible. To reach a wavelength of 6 nanometers, the TESLA Test Facility (TTF) currently under construction at DESY is extended to 1 GeV beam energy. Because

Jrg Rossbach

1997-01-01

122

The TESLA RF System  

Microsoft Academic Search

The TESLA project proposed by the TESLA collaboration in 2001 is a 500 to 800GeV e+\\/e- linear collider with integrated free electron laser facility. The accelerator is based on superconducting cavity technology. Approximately 20000 superconducting cavities operated at 1.3GHz with a gradient of 23.4MV\\/m or 35MV\\/m will be required to achieve the energy of 500GeV or 800GeV respectively. For 500GeV

S. Choroba

2003-01-01

123

MR-Guided Freehand Biopsy of Liver Lesions With Fast Continuous Imaging Using a 1.0-T Open MRI Scanner: Experience in 50 Patients  

SciTech Connect

The purpose of this study was to assess a new open system with a field-strength of 1.0 T for the feasibility of liver biopsy using the freehand technique with fast continuous imaging. Fifty patients with focal liver lesions measuring 5 to 30 mm in diameter were included in the study. Guidance and monitoring was performed using a 1.0-T open magnetic resonance (MR) scanner (Panorama HFO; Philips Healthcare, Best, The Netherlands). With fast continuous imaging using a T1-weighted (T1W) gradient echo (GRE) sequence after administration of gadolinium (Gd)-EOB-DTPA, the needle was placed into the lesion. An interface for interactive dynamic viewing in two perpendicular planes prevented needle deviations T2-weighted turbo spin echo (TSE) fat-suppressed sequence was added to rule out postinterventional hematoma or biloma. All lesions were visible on the interventional images. Biopsy was technically successful, and solid specimens were obtained in all cases. Forty-six patients showed a histopathologic pattern other than native liver tissue, thus confirming correct position of the needle. Time between determination of the lesion and performance of the control scan was on average 18 min. No major complications were recorded. MR guidance with the new 1-T open system must be considered an attractive alternative for liver punction. An interface for dynamic imaging of needle guidance and T1W-GRE imaging with administration of Gd-EOB-DTPA for contrast enhancement allows the pinpoint puncture of liver lesions.

Fischbach, Frank, E-mail: frank.fischbach@med.ovgu.de [Otto von Guericke University, Department of Radiology, Medical School (Germany); Bunke, Juergen [Philips Healthcare (Germany); Thormann, Markus; Gaffke, Gunnar; Jungnickel, Kerstin [Otto von Guericke University, Department of Radiology, Medical School (Germany); Smink, Jouke [Philips Healthcare (Germany); Ricke, Jens [Otto von Guericke University, Department of Radiology, Medical School (Germany)

2011-02-15

124

TESLA-Report 1994-31 TESLA-Report 1994-31  

E-print Network

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125

TESLA-Report 1994-24 TESLA-Report 1994-24  

E-print Network

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126

TESLA-Report 1994-11 TESLA-Report 1994-11  

E-print Network

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127

TESLA-Report 1993-39 TESLA-Report 1993-39  

E-print Network

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128

TESLA-Report 1996-12 TESLA-Report 1996-12  

E-print Network

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129

TESLA-Report 1999-18 TESLA-Report 1999-18  

E-print Network

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130

TESLA FEL-Report 1999-04 TESLA FEL-Report 1999-07  

E-print Network

TESLA FEL-Report 1999-04 TESLA FEL-Report 1999-07 #12;TESLA FEL-Report 1999-04 TESLA FEL-Report 1999-07 #12;TESLA FEL-Report 1999-04 TESLA FEL-Report 1999-07 #12;TESLA FEL-Report 1999-04 TESLA FEL-Report 1999-07 #12;TESLA FEL-Report 1999-04 TESLA FEL-Report 1999-07 #12;TESLA FEL-Report 1999-04 TESLA FEL

131

TESLA-Report 1994-17 TESLA-Report 1994-17  

E-print Network

TESLA-Report 1994-17 #12;TESLA-Report 1994-17 #12;TESLA-Report 1994-17 #12;TESLA-Report 1994-17 #12;TESLA-Report 1994-17 #12;TESLA-Report 1994-17 #12;TESLA-Report 1994-17 #12;TESLA-Report 1994-17 #12;TESLA-Report 1994-17 #12;TESLA-Report 1994-17 #12;TESLA-Report 1994-17 #12;TESLA-Report 1994-17 #12

132

Photon collider at TESLA  

E-print Network

High energy photon colliders (gamma-gamma, gamma-electron) based on backward Compton scattering of laser light is a very natural addition to e+e- linear colliders. In this report we consider this option for the TESLA project. Recent study has shown that the horizontal emittance in the TESLA damping ring can be further decreased by a factor of four. In this case the gamma-gamma luminosity luminosity in the high energy part of spectrum can reach (1/3)L_{e+e-}. Typical cross sections of interesting processes in gamma-gamma collisions are higher than those in e+e- collisions by about one order of magnitude, so the number of events in gamma-gamma collisions will be more than that in e+e- collisions. Photon colliders can, certainly, give additional information and they are the best for the study of many phenomena. The main question is now the technical feasibility. The key new element in photon colliders is a very powerful laser system. An external optical cavity is a promising approach for the TESLA project. A free electron laser is another option. However, a more straightforward solution is ``an optical storage ring (optical trap)'' with diode pumped solid state laser injector which is today technically feasible. This paper briefly reviews the status of a photon collider based at TESLA, its possible parameters and existing problems.

Valery Telnov

2000-10-13

133

The TESLA Detector  

E-print Network

For the superconducting linear collider TESLA a multi purpose detector has been designed. This detector is optimised for the important physics processes expected at a next generation linear collider up to around 1 TeV and is designed for the specific environment of a superconducting collider.

Klaus Moenig

2001-11-05

134

Assessment of swallowing and its disorders-a dynamic MRI study.  

PubMed

Magnetic resonance imaging overcomes the limitations of videofluoroscopy in assessing without radiation exposure. The clinical utility of dynamic MRI for swallowing disorders is not well documented. This study demonstrates the feasibility of using dynamic MRI in assessment of swallowing disorders. Ten normal and three brainstem lesion patients participated in this study. GE Signa HDxt 1.5 Tesla MRI scanner with head-and-neck coil as a receiver and fast imaging employing steady state acquisition sequence was used. The swallow was analyzed in terms of symmetry and amplitude of movements of velum, faucial pillars, tongue, epiglottis and cricopharyngeous and images from the sagittal, coronal and axial planes. In sagittal plane posterior movement of tongue and its compression on velum, elevation of hyoid bone, elevation of larynx and lid action of epiglottis, in the coronal view the symmetrical movements of the faucial pillars and pharyngeal constrictor muscles and in axial plane three anatomical landmarks were targeted based on their role in swallowing, viz. velum, epiglottis and cricopharyngeous were studied. In brainstem lesion individuals, posterior movement of tongue, and elevation of larynx were not seen. Asymmetrical movements of faucial pillars and cricopharyngeous muscle were appreciated in the dynamic MRI. This demonstrates that, dynamic MRI is an efficient tool to understand the swallowing physiology and helps the speech language pathologist in modifying the swallowing maneuvers. Dynamic MRI is an effective tool in assessing swallowing and its disorders. This muscle specific information is not appreciated in videofluoroscopy and this information is necessary to modify the therapy maneuvers. PMID:23068561

Vijay Kumar, K V; Shankar, V; Santosham, Roy

2013-02-01

135

Impairment of chondrocyte biosynthetic activity by exposure to 3-tesla high-field magnetic resonance imaging is temporary  

Microsoft Academic Search

The influence of magnetic resonance imaging (MRI) devices at high field strengths on living tissues is unknown. We investigated the effects of a 3-tesla electromagnetic field (EMF) on the biosynthetic activity of bovine articular cartilage. Bovine articular cartilage was obtained from juvenile and adult animals. Whole joints or cartilage explants were subjected to a pulsed 3-tesla EMF; controls were left

Ilse-Gerlinde Sunk; Siegfried Trattnig; Winfried B Graninger; Love Amoyo; Birgit Tuerk; Carl-Walter Steiner; Josef S Smolen; Klaus Bobacz

2006-01-01

136

TESLA Linear-Collider Projekt Abbildung 134: Das hydrogeologische Profil entlang der TESLA-Trasse. Der TESLA-  

E-print Network

TESLA Linear-Collider Projekt Abbildung 134: Das hydrogeologische Profil entlang der TESLA-Trasse. Der TESLA- Tunnel liegt in wasserdurchlässigen und -undurchlässigen Schichten. Die wasserdurch gesättigt. 230 #12;TESLA Linear-Collider Projekt Voruntersuchungen zum TESLA Linear-Collider Projekt Ein

137

Prostate magnetic resonance imaging at 3 Tesla: Is administration of hyoscine-N-butyl-bromide mandatory?  

PubMed Central

AIM: To evaluate the value of administration of hyoscine-N-butyl-bromide (HBB) for image quality magnetic resonance imaging (MRI) of the prostate. METHODS: Seventy patients were retrospectively included in the study. Thirty-five patients were examined with administration of 40 milligrams of HBB (Buscopan; Boehringer, Ingelheim, Germany); 35 patients were examined without HBB. A multiparametric MRI protocol was performed on a 3.0 Tesla scanner without using an endorectal coil. The following criteria were evaluated independently by two experienced radiologists on a five-point Likert scale: anatomical details (delineation between peripheral and transitional zone of the prostate, visualisation of the capsule, depiction of the neurovascular bundles); visualisation of lymph nodes; motion related artefacts; and overall image quality. RESULTS: Comparison of anatomical details between the two cohorts showed no statistically significant difference (3.9 0.7 vs 4.0 0.9, P = 0.54, and 3.8 0.7 vs 4.2 0.6, P = 0.07) for both readers. There was no significant advantage regarding depiction of local and iliac lymph nodes (3.9 0.6 vs 4.2 0.6, P = 0.07, and 3.8 0.9 vs 4.1 0.8, P = 0.19). Motion artefacts were rated as none to few in both groups and showed no statistical difference (2.3 1.0 vs 1.9 0.9, P = 0.19, and 2.3 1.1 vs 1.9 0.7, P = 0.22). Overall image quality was rated good in average for both cohorts without significant difference (4.0 0.6 vs 4.0 0.9, P = 0.78, and 3.8 0.8 vs 4.2 0.6, P = 0.09). CONCLUSION: The results demonstrated no significant effect of HBB administration on image quality. The study suggests that use of HBB is not mandatory for MRI of the prostate at 3.0 Tesla. PMID:23908696

Roethke, Matthias C; Kuru, Timur H; Radbruch, Alexander; Hadaschik, Boris; Schlemmer, Heinz-Peter

2013-01-01

138

SASE FEL at the TESLA Facility, Phase 2 The TESLA Test Facility FEL team  

E-print Network

SASE FEL at the TESLA Facility, Phase 2 The TESLA Test Facility FEL team June 2002, TESLA-FEL 2002-01 #12;SASE FEL at the TESLA Facility, Phase 2 Abstract The last description of the TESLA Test Facility FEL has been written in 1995 (TESLA- FEL report 95-03). Since then, many changes have developed

139

[Optimized magnetic resonance sequences and parameters with operative assisted images for radical prostatectomy at 3 tesla-magnetic resonance image].  

PubMed

The objective of our study was to optimize magnetic resonance image (MRI) sequences and parameters using operative assisted images (three-dimensional images) for radical prostatectomy at 3 tesla (T) MRI. Five healthy volunteers underwent MRI on the 3.0 T scanner. Various sequences and parameters [Cube (TE/TR = 18, 50, 90 ms/2000 ms), FIESTA (TE/TR/FA = 2.4 ms/5 ms/40 degrees, 90 degrees), fSPGR (TE/TR/FA = 2.3 ms/11.2 ms/20 degrees), slice thickness = 1.2 mm, matrix = 192 x 160] were respectively compared. Several structures of the pelvis (the central zones and transition zones of the prostate, the peripheral zones of the prostate, seminal vesicles, rectum wall, bladder, muscle and fat) were determined. The signal intensities of these structures were measured on reformatted axial images and compared against several structures of the pelvis. Correlation with various sequences and parameters was based on the signal-to-noise ratio (SNR), the contrast ratio (CR) and the presence of artifacts. Student's t-test was used for statistical analysis. With Cube (TE/TR = 50 ms/2000 ms), the average value of visual evaluation with artifacts was high, and SNR and CR were higher than for other sequence and parameters. Optimized MRI sequences and parameters were Cube (TE/TR = 50 ms/2000 ms) which provides improved SNR and CR and the presence of artifacts with operative assisted images for radical prostatectomy. These operative assisted images obtained from Cube (TE/TR = 50 ms/2000 ms) are likely to be useful for surgery. PMID:23964533

Shirase, Ryuji; Sakurai, Yuuki; Nagahama, Hiroshi; Harada, Kuniaki; Takashima, Hiroyuki; Nakanishi, Mitsuhiro; Harada, Kohei; Shishido, Hiroki; Imamura, Rui; Sakata, Motomichi; Hatakenaka, Masamitsu

2013-05-01

140

Inter-study reproducibility of arterial spin labelling magnetic resonance imaging for measurement of renal perfusion in healthy volunteers at 3 Tesla  

PubMed Central

Background Measurement of renal perfusion is a crucial part of measuring kidney function. Arterial spin labelling magnetic resonance imaging (ASL MRI) is a non-invasive method of measuring renal perfusion using magnetised blood as endogenous contrast. We studied the reproducibility of ASL MRI in normal volunteers. Methods ASL MRI was performed in healthy volunteers on 2 occasions using a 3.0 Tesla MRI scanner with flow-sensitive alternating inversion recovery (FAIR) perfusion preparation with a steady state free precession (True-FISP) pulse sequence. Kidney volume was measured from the scanned images. Routine serum and urine biochemistry were measured prior to MRI scanning. Results 12 volunteers were recruited yielding 24 kidneys, with a mean participant age of 44.1 14.6 years, blood pressure of 136/82 mmHg and chronic kidney disease epidemiology formula estimated glomerular filtration rate (CKD EPI eGFR) of 98.3 15.1 ml/min/1.73 m2. Mean kidney volumes measured using the ellipsoid formula and voxel count method were 123.5 25.5 cm3, and 156.7 28.9 cm3 respectively. Mean kidney perfusion was 229 41 ml/min/100 g and mean cortical perfusion was 327 63 ml/min/100 g, with no significant differences between ASL MRIs. Mean absolute kidney perfusion calculated from kidney volume measured during the scan was 373 71 ml/min. Bland Altman plots were constructed of the cortical and whole kidney perfusion measurements made at ASL MRIs 1 and 2. These showed good agreement between measurements, with a random distribution of means plotted against differences observed. The intra class correlation for cortical perfusion was 0.85, whilst the within subject coefficient of variance was 9.2%. The intra class correlation for whole kidney perfusion was 0.86, whilst the within subject coefficient of variance was 7.1%. Conclusions ASL MRI at 3.0 Tesla provides a repeatable method of measuring renal perfusion in healthy subjects without the need for administration of exogenous compounds. We have established normal values for renal perfusion using ASL MRI in a cohort of healthy volunteers. PMID:24484613

2014-01-01

141

TESLA-Report 1999-05 TESLA-Report 1999-05  

E-print Network

TESLA-Report 1999-05 1 of 38 #12;TESLA-Report 1999-05 2 of 38 #12;TESLA-Report 1999-05 3 of 38 #12;TESLA-Report 1999-05 4 of 38 #12;TESLA-Report 1999-05 5 of 38 #12;TESLA-Report 1999-05 6 of 38 #12;TESLA-Report 1999-05 7 of 38 #12;TESLA-Report 1999-05 8 of 38 #12;TESLA-Report 1999-05 9 of 38 #12;TESLA-Report 1999

142

High-Field fMRI for Human Applications: An Overview of Spatial Resolution and Signal Specificity  

PubMed Central

In the last decade, dozens of 7 Tesla scanners have been purchased or installed around the world, while 3 Tesla systems have become a standard. This increased interest in higher field strengths is driven by a demonstrated advantage of high fields for available signal-to-noise ratio (SNR) in the magnetic resonance signal. Functional imaging studies have additional advantages of increases in both the contrast and the spatial specificity of the susceptibility based BOLD signal. One use of this resultant increase in the contrast to noise ratio (CNR) for functional MRI studies at high field is increased image resolution. However, there are many factors to consider in predicting exactly what kind of resolution gains might be made at high fields, and what the opportunity costs might be. The first part of this article discusses both hardware and image quality considerations for higher resolution functional imaging. The second part draws distinctions between image resolution, spatial specificity, and functional specificity of the fMRI signals that can be acquired at high fields, suggesting practical limitations for attainable resolutions of fMRI experiments at a given field, given the current state of the art in imaging techniques. Finally, practical resolution limitations and pulse sequence options for studies in human subjects are considered. PMID:22216080

Olman, Cheryl A; Yacoub, Essa

2011-01-01

143

Note: Tesla transformer damping.  

PubMed

Unexpected heavy damping in the two winding Tesla pulse transformer is shown to be due to small primary inductances. A small primary inductance is a necessary condition of operability, but is also a refractory inefficiency. A 30% performance loss is demonstrated using a typical "spiral strip" transformer. The loss is investigated by examining damping terms added to the transformer's governing equations. A significant alteration of the transformer's architecture is suggested to mitigate these losses. Experimental and simulated data comparing the 2 and 3 winding transformers are cited to support the suggestion. PMID:22852736

Reed, J L

2012-07-01

144

A Phantom for Diffusion MRI  

Cancer.gov

Combining a Diffusion MRI phantom with a resolution phantom would allow the same device to be used to calibrate an MR scanner''s image quality and the accuracy and precision of its diffusion measurements. This would be useful particularly for Radiological QA and for use in assuring data quality in longitudinal and multi-subject studies.

145

PBS: Tesla - Master of Lightning  

NSDL National Science Digital Library

This web site explores the life and legacy of Nikola Tesla, an important contributor to the field of electromagnetism. Although the significance of his work is often minimized, Tesla's work formed the basis of modern alternating current power systems and wireless transmission of energy. He was the first to receive a patent for the invention of the radio, though Marconi is more often given credit for the discovery. The web site includes interactive explorations of Tesla's key inventions and lesson plans for grades 6-12 on electric potential and conversion of electrical energy into mechanical energy. Users will also find selected articles on Tesla, timelines of electricity and radio, and a link to view selected Tesla patents.

2010-06-24

146

TESLA-LNF TECHNICAL NOTE Divisione Acceleratori  

E-print Network

TESLA-LNF TECHNICAL NOTE _____________ Divisione Acceleratori Frascati, November 20, 2003 Note: TESLA Report 2003-26 TESLA DAMPING RING: INJECTION/EXTRACTION SCHEMES WITH RF DEFLECTORS D. Alesini, S/extraction schemes in the Damping Ring of TESLA using RF deflectors. We illustrate different possible solutions using

147

Tesla TechFair Call for Proposals  

E-print Network

Tesla TechFair Call for Proposals Thayer School of Engineering and the Hopkins Center are celebrating Nikola Tesla, in conjunction with Tesla in New York, an opera by filmmaker Jim Jarmusch & composer Phil Kline. Thayer will host a Tesla TechFair, including a panel discussion and demonstrations

148

TESLA'S VISION OF THE WIRELESS GLOBAL COMMUNICATIONS  

E-print Network

TESLA'S VISION OF THE WIRELESS GLOBAL COMMUNICATIONS Ljiljana Trajkovi Communication Networks;March 12, 2004 Kwantlen College Ljiljana Trajkovic, Simon Fraser University 2 Road map Tesla in 1890's Alternate currents Tesla left Edison in 1885. He formed his own laboratory "Tesla Electric Company" in 1887

Trajkovic, Ljiljana

149

FEB 19, 2001 TESLA-2001-17  

E-print Network

­i­ FEB 19, 2001 TESLA-2001-17 CONCEPTUAL DESIGN FOR THE FINAL FOCUS QUADRUPOLE MAGNETS FOR TESLA A a preliminary design of the superconducting final focusing quadrupole magnets for TESLA and all their associated The Tera Electron volts Superconducting Linear Accelerator (TESLA) is an electron/positron linear collider

150

FEB 19, 2001 TESLA-2001-17  

E-print Network

­i­ FEB 19, 2001 TESLA-2001-17 CONCEPTUAL DESIGN FOR THE FINAL FOCUS QUADRUPOLE MAGNETS FOR TESLA A a preliminary design of the superconducting final focusing quadrupole magnets for TESLA and all their associated Electron volts Superconducting Linear Accelerator (TESLA) is an electron/positron linear collider

151

Nikola Tesla: 145 years of visionary ideas  

Microsoft Academic Search

The paper gives a short review of Tesla's major inventions including the rotating magnetic field, the Tesla coil and transformer, and the power struggle between Edison's direct current systems and the Tesla-Westinghouse alternating current approach. It also looks at some of Tesla's visionary ideas

Jasmina Vujic; Aleksandar Marincic; Milos Ercegovac; Bratislav Milovanovic

2001-01-01

152

[70 years of Nikola Tesla studies].  

PubMed

Nikola Tesla's studies of chemistry are described including his not very scholarly affair in Maribor. After almost a century and half of hypothesis at least usable scenario of Tesla's life and "work" in Maribor is provided. The chemistry achievements of Tesla's most influential professors Martin Sekuli? and Tesla's Graz professors are put into the limelight. The fact that Tesla in Graz studied on the technological chemistry Faculty of Polytechnic is focused. PMID:23878954

Juznic, Stanislav

2013-01-01

153

[Nikola Tesla in medicine, too].  

PubMed

Using primary and secondary sources we have shown in this paper the influence of Nikola Tesla's work on the field of medicine. The description of his experiments conduced within secondary-school education programs aimed to present the popularization of his work in Croatia. Although Tesla was dedicated primarily to physics and was not directly involved in biomedical research, his work significantly contributed to paving the way of medical physics particularly radiology and high-frequency electrotherapy. PMID:18383745

Hanzek, Branko; Jakobovi?, Zvonimir

2007-12-01

154

Volitional reduction of anterior cingulate cortex activity produces decreased cue craving in smoking cessation: a preliminary real-time fMRI study.  

PubMed

Numerous research groups are now using analysis of blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) results and relaying back information about regional activity in their brains to participants in the scanner in 'real time'. In this study, we explored the feasibility of self-regulation of frontal cortical activation using real-time fMRI (rtfMRI) neurofeedback in nicotine-dependent cigarette smokers during exposure to smoking cues. Ten cigarette smokers were shown smoking-related visual cues in a 3 Tesla MRI scanner to induce their nicotine craving. Participants were instructed to modify their craving using rtfMRI feedback with two different approaches. In a 'reduce craving' paradigm, participants were instructed to 'reduce' their craving, and decrease the anterior cingulate cortex (ACC) activity. In a separate 'increase resistance' paradigm, participants were asked to increase their resistance to craving and to increase middle prefrontal cortex (mPFC) activity. We found that participants were able to significantly reduce the BOLD signal in the ACC during the 'reduce craving' task (P=0.028). There was a significant correlation between decreased ACC activation and reduced craving ratings during the 'reduce craving' session (P=0.011). In contrast, there was no modulation of the BOLD signal in mPFC during the 'increase resistance' session. These preliminary results suggest that some smokers may be able to use neurofeedback via rtfMRI to voluntarily regulate ACC activation and temporarily reduce smoking cue-induced craving. Further research is needed to determine the optimal parameters of neurofeedback rtfMRI, and whether it might eventually become a therapeutic tool for nicotine dependence. PMID:22458676

Li, Xingbao; Hartwell, Karen J; Borckardt, Jeffery; Prisciandaro, James J; Saladin, Michael E; Morgan, Paul S; Johnson, Kevin A; Lematty, Todd; Brady, Kathleen T; George, Mark S

2013-07-01

155

Brain Activation in Response to Visually Evoked Sexual Arousal in Male-to-Female Transsexuals: 3.0 Tesla Functional Magnetic Resonance Imaging  

PubMed Central

Objective This study used functional magnetic resonance imaging (fMRI) to contrast the differential brain activation patterns in response to visual stimulation with both male and female erotic nude pictures in male-to-female (MTF) transsexuals who underwent a sex reassignment surgery. Materials and Methods A total of nine healthy MTF transsexuals after a sex reassignment surgery underwent fMRI on a 3.0 Tesla MR Scanner. The brain activation patterns were induced by visual stimulation with both male and female erotic nude pictures. Results The sex hormone levels of the postoperative MTF transsexuals were in the normal range of healthy heterosexual females. The brain areas, which were activated by viewing male nude pictures when compared with viewing female nude pictures, included predominantly the cerebellum, hippocampus, putamen, anterior cingulate gyrus, head of caudate nucleus, amygdala, midbrain, thalamus, insula, and body of caudate nucleus. On the other hand, brain activation induced by viewing female nude pictures was predominantly observed in the hypothalamus and the septal area. Conclusion Our findings suggest that distinct brain activation patterns associated with visual sexual arousal in postoperative MTF transsexuals reflect their sexual orientation to males. PMID:22563262

Oh, Seok-Kyun; Kim, Gwang-Won; Yang, Jong-Chul; Kim, Seok-Kwun; Kang, Heoung-Keun

2012-01-01

156

TESLA superconducting RF cavity development: For the TESLA collaboration  

NASA Astrophysics Data System (ADS)

The TESLA collaboration has made steady progress since its first official meeting at Cornell in 1990. The infrastructure necessary to assemble and test superconducting rf cavities has been installed at the TESLA Test Facility (TTF) at DESY. 5-cell, 1.3 GHz cavities have been fabricated and have reached accelerating fields of 25 MV/m. Full sized 9-cell copper cavities of TESLA geometry have been measured to verify the higher order modes present and to evaluate HOM coupling designs. The design of the TESLA 9-cell cavity has been finalized and industry has started delivery. Two prototype 9-cell niobium cavities in their first tests have reached accelerating fields of 10 MV/m and 15 MV/m in a vertical dewar after high peak power (HPP) conditioning. The first 12 m TESLA cryomodule that will house 8 9-cell cavities is scheduled to be delivered in Spring 1995. A design report for the TTF is in progress. The TTF test linac is scheduled to be commissioned in 1996/1997.

Koepke, Karl; Tesla Collaboration

1995-05-01

157

Workflow assessment of 3T MRI-guided transperineal targeted prostate biopsy using a robotic needle guidance  

NASA Astrophysics Data System (ADS)

Magnetic resonance imaging (MRI) guided transperineal targeted prostate biopsy has become a valuable instrument for detection of prostate cancer in patients with continuing suspicion for aggressive cancer after transrectal ultrasound guided (TRUS) guided biopsy. The MRI-guided procedures are performed using mechanical targeting devices or templates, which suffer from limitations of spatial sampling resolution and/or manual in-bore adjustments. To overcome these limitations, we developed and clinically deployed an MRI-compatible piezoceramic-motor actuated needle guidance device, Smart Template, which allows automated needle guidance with high targeting resolution for use in a wide closed-bore 3-Tesla MRI scanner. One of the main limitations of the MRI-guided procedure is the lengthy procedure time compared to conventional TRUS-guided procedures. In order to optimize the procedure, we assessed workflow of 30 MRI-guided biopsy procedures using the Smart Template with focus on procedure time. An average of 3.4 (range: 2~6) targets were preprocedurally selected per procedure and 2.2 0.8 biopsies were performed for each target with an average insertion attempt of 1.9 0.7 per biopsy. The average technical preparation time was 14 7 min and the in-MRI patient preparation time was 42 7 min. After 21 7 min of initial imaging, 64 12 min of biopsy was performed yielding an average of 10 2 min per tissue sample. The total procedure time occupying the MRI suite was 138 16 min. No noticeable tendency in the length of any time segment was observed over the 30 clinical cases.

Song, Sang-Eun; Tuncali, Kemal; Tokuda, Junichi; Fedorov, Andriy; Penzkofer, Tobias; Fennessy, Fiona; Tempany, Clare; Yoshimitsu, Kitaro; Magill, John; Hata, Nobuhiko

2014-03-01

158

Functional MR imaging of the awake monkey in a novel vertical large-bore 7 Tesla setup J. Pfeuffer1  

E-print Network

Functional MR imaging of the awake monkey in a novel vertical large-bore 7 Tesla setup J. Pfeuffer1MRI BOLD signal [2,3]. Here we present the first results from a novel high field (7T), large- bore (60cm The 7 Tesla magnet has a 60 cm bore, an overall height of 6.40 m, and an empty weight of 80 tons

Jegelka, Stefanie

159

Review of quantitative MRI principles for gel dosimetry  

Microsoft Academic Search

The radiation dose distribution absorbed by polymer gel dosimeters can be read out by several methods such as magnetic resonance imaging (MRI), optical CT, X-ray CT and ultrasound. MRI was the first method that was explored to read out polymer gel dosimeters. Although MRI was soon recognised as a promising technique, limited access to MRI scanners and the often (wrongly

Yves DeDeene

2009-01-01

160

Status of the TESLA Test Facility Linac H. Weise, for the TESLA Collaboration  

E-print Network

Status of the TESLA Test Facility Linac H. Weise, for the TESLA Collaboration Deutsches Elektronen-Synchrotron DESY D-22603 Hamburg, Germany Abstract The TTF linac, a major effort of the TESLA Test Facility, is now GeV collider is the usage of superconducting (s.c.) accelerating structures. The international TESLA

161

TESLA 2004-14 Test Measurements of a new TESLA Cavity  

E-print Network

TESLA 2004-14 Test Measurements of a new TESLA Cavity Beam Position Monitor at the ELBE Linac V Abstract A new type of a cavity BPM proposed for beam position determination along the TESLA linac to TESLA would fulfil the demands for precise bunch-to-bunch position determination. Possible improvements

162

1 of 5 Copyright 2007 Tesla Motors Updated: December 19, 2007 The Tesla Roadster Battery System  

E-print Network

1 of 5 Copyright © 2007 Tesla Motors Updated: December 19, 2007 The Tesla Roadster Battery System Tesla Motors August 16, 2006 By Gene Berdichevsky, Kurt Kelty, JB Straubel and Erik Toomre Summary This paper provides details about the design of the Tesla Roadster's lithium-ion (Li-ion) battery pack

Laughlin, Robert B.

163

26 July 2000 TESLA Report 2000-13 Compensation of Solenoid Effects at the TESLA  

E-print Network

26 July 2000 TESLA Report 2000-13 Compensation of Solenoid Effects at the TESLA Interaction Point at the TESLA interaction point is 5 nm. The long solenoid encompassing the detector introduces coupling effects along the beam line. This is a concern for a linear collider such as TESLA, where the vertical beam size

164

PERFORMANCE OF THE TESLA TEST FACILITY LINAC for the TESLA Collaboration  

E-print Network

PERFORMANCE OF THE TESLA TEST FACILITY LINAC P. Castro for the TESLA Collaboration Abstract In order to test the performance of a superconducting linac, the TESLA Collaboration has built and operated for the TESLA design. Results of recent running periods will be summarized in this paper. 1 INTRODUCTION

165

TESLA Report 2003-28 TESLA cavity modeling and digital implementation  

E-print Network

TESLA Report 2003-28 TESLA cavity modeling and digital implementation with FPGA technology solution, Warsaw University of Technology Stefan Simrock TESLA, DESY, Hamburg ABSTRACT The cavity resonator modeling for the TESLA - TeV­Energy Superconducting Linear Accelerator project is initially introduced

166

UC Santa Cruz Tesla at Aptos HighUC Santa Cruz Tesla at Aptos HighSCIPP UC Santa Cruz  

E-print Network

UC Santa Cruz Tesla at Aptos HighUC Santa Cruz Tesla at Aptos HighSCIPP UC Santa Cruz UC Santa Cruz Tesla Coil ShowUC Santa Cruz Tesla Coil Show at Aptos High Schoolat Aptos High School #12;UC Santa Cruz Tesla at Aptos HighUC Santa Cruz Tesla at Aptos HighSCIPP UC Santa Cruz Santa Cruz Institute

California at Santa Cruz, University of

167

Programmable infusion pump and catheter: evaluation using 3-tesla magnetic resonance imaging.  

PubMed

Objective.? This study assessed 3-Tesla magnetic resonance imaging (MRI) issues for a programmable infusion pump and associated catheters. Methods.? A programmable infusion pump and associated catheters (MedStream Programmable Infusion Pump, 40mL; SureStream TI Coil-Reinforced Intraspinal Catheter; SureStream TI Connector; and SureStream Silicone Catheter; Codman and Shurtleff Inc., a Johnson & Johnson Company, Raynham, MA, USA) underwent evaluation for magnetic field interactions (deflection angle and torque), heating (transmit/receive body radiofrequency coil; whole-body averaged specific absorption rate, 3W/kg for 15min), functional changes (before and after MRI using eight different MRI conditions), and artifacts (T1-weighted spin-echo and gradient-echo pulse sequences) at 3-Tesla. Results.? The programmable infusion pump and associated catheters exhibited minor magnetic field interactions. Heating was not excessive (?1.9), especially considering the experimental conditions used for this evaluation (ie, relatively high radiofrequency power/specific absorption rate level and use of a nonperfused phantom). The function of three out of six pumps was temporarily altered by exposures to 3-Tesla MRI conditions. Reset was achieved in each case. Artifacts were relatively large for the pump and minor for the catheter. Conclusions.? The programmable infusion pump and catheters will not pose increased risk to a patient examined using 3-Tesla MRI as long as specific safety guidelines are followed, which includes interrogation of the pump post-MRI to ensure proper settings. Artifacts for the programmable infusion pump may impact the diagnostic use of MRI if the area of interest is in the same area or near the device. PMID:22151092

Shellock, Frank G; Crivelli, Rocco; Venugopalan, Ramakrishna

2008-07-01

168

LCPHSM200059TESLA 29th December 2000  

E-print Network

. At TESLA electrons should be polarizable to about 80% using the same technology as at SLD. HoweverLC­PHSM­2000­59­TESLA 29th December 2000 The use of Positron Polarization for precision in the interaction can be of the same size. For a high luminosity collider like TESLA this can strongly limit the use

169

LCDETxxxxxxx Improved TESLA Optics and Beam Induced  

E-print Network

LC­DET­xxxx­xxx Improved TESLA Optics and Beam Induced Backgrounds Update Karsten B?u?er, DESY and Olivier Napoly, CEA/Saclay LCWS 2002, Jeju, Korea Abstract A new tesla optics with l*=5m is under development. An update is given on the simulation of the beam induced backgrounds in the TESLA detector. 1

170

TESLA'S VISION OF THE WIRELESS GLOBAL COMMUNICATIONS  

E-print Network

TESLA'S VISION OF THE WIRELESS GLOBAL COMMUNICATIONS Ljiljana Trajkovi Communication Networks;January 17, 2005 UBC Ljiljana Trajkovic, Simon Fraser University 2 Road map Tesla in 1890's First wireless;January 17, 2005 UBC Ljiljana Trajkovic, Simon Fraser University 4 Alternate currents Tesla left Edison

Trajkovic, Ljiljana

171

Image quality and signal distribution in 1.5-T and 3-T MRI in mild traumatic brain injury patients  

NASA Astrophysics Data System (ADS)

Clear standards are lacking in the imaging modalities of the deficit in mild traumatic brain injury (MTBI) patients. The purpose of this study is to compare the image quality by signal distribution between 1.5 Tesla and 3 Tesla MRI in turbo spin echo (TSE) and gradient echo (GRE) images in normal hospital settings and to find preferences for which field to use in MTBI patients. We studied 40 MTBI patients with TSE and GRE; 20 patients were imaged at 1.5 T and 20 at 3 T. The imaging parameters were optimized separately for the two scanners. Histograms of the signal distribution in 22 ROIs were fitted to a 1-peak Gaussian model and the resulting peak positions were scaled in respect to the peak positions of genu of the corpus callosum and the caudate nuclei. Correlation of the contrast of the ROIs in reference to genu of the corpus callosum between both the two scanners and the two imaging sequences was good. Image contrast was similar at both in the TSE images; in the GRE images contrast improved from 1.5 T to 3 T. However, based on peak positions and widths, a slight drawback in the separability between the ROIs was observed when 1.5 T MRI was replaced by 3 T. No clear improvement in tissue contrast or separability of 3 T was found compared to 1.5 T. Imaging of MTBI with 3 T should therefore be based on other advantages of high-field imaging, such as improved SNR and spatial resolution.

Rossi, Maija E.; Dastidar, Prasun; Ryymin, Pertti; Ylinen, Aarne; hman, Juha; Soimakallio, Seppo; Eskola, Hannu

2009-02-01

172

Liquid-explosives scanners stand trial in airports  

SciTech Connect

Air passengers may once more be allowed to pack beverages, lotions, and hair spray in their carry-on luggage, if imaging technologies to detect liquid explosives can prove their worth. Several competing systems, including multi-energy x-ray systems and a low-field magnetic resonance imaging (MRI) scanner, are undergoing field tests at some airports worldwide.

Matthews, Jermey N. A.

2010-07-15

173

Initial experience of 3 tesla endorectal coil magnetic resonance imaging and 1H-spectroscopic imaging of the prostate  

Microsoft Academic Search

RATIONALE AND OBJECTIVES: We sought to explore the feasibility of magnetic resonance imaging (MRI) of the prostate at 3T, with the knowledge of potential drawbacks of MRI at high field strengths. MATERIAL AND METHOD: MRI, dynamic MRI, and 1H-MR spectroscopic imaging were performed in 10 patients with prostate cancer on 1.5T and 3T whole-body scanners. Comparable scan protocols were used,

J. J. Ftterer; Tom W. J. Scheenen; Henkjan J. Huisman; Dennis W. J. Klomp; Ferdi A. van Dorsten; J Alfred Witjes; Arend Heerschap; Jelle O. Barentsz

2004-01-01

174

The TESLA Free Electron Laser  

NASA Astrophysics Data System (ADS)

The TESLA Free Electron Laser makes use of the high quality electron beam that can be provided by the superconducting TESLA linac to drive a single pass free electron laser (FEL) at wavelengths far below the visible. To reach a wavelength of 6 nanometers, the TESLA Test Facility (TTF) currently under construction at DESY will be extended to 1 GeV beam energy. Because there are no mirrors and seed-lasers in this wavelength regime, the principle of Self-Amplified-Spontaneous-Emission (SASE) will be employed. A first test of both the principle and technical components is foreseen at a photon wavelength larger than 42 nanometers. With respect to linac technology, the key prerequisite for such single-pass, high-gain FELs is a high intensity, diffraction limited, electron beam to be generated and accelerated without degradation. Key components are RF guns with photocathodes, bunch compressors, and related diagnostics. The status of design and construction as well as both electron and photon beam properties will be discussed. Once proven in the micrometer to nanometer regime, the SASE FEL scheme is considered applicable down to Angstrom wavelengths. It is pointed out that this latter option is particularly of interest in context with the construction of a linear collider, which requires very similar beam parameters. The status of conceptual design work on such a coherent X-ray user facility integrated into the TESLA linear collider design will be briefly sketched.

Rossbach, Jrg

1997-05-01

175

The TESLA Time Projection Chamber  

E-print Network

A large Time Projection Chamber is proposed as part of the tracking system for a detector at the TESLA electron positron linear collider. Different ongoing R&D studies are reviewed, stressing progress made on a new type readout technique based on Micro-Pattern Gas Detectors.

Nabil Ghodbane

2002-12-12

176

Nikola Tesla Educational Opportunity School.  

ERIC Educational Resources Information Center

Describes the architectural design, costs, general description, and square footage data for the Nikola Tesla Educational Opportunity School in Colorado Springs, Colorado. A floor plan and photos are included along with a list of manufacturers and suppliers used for the project. (GR)

Design Cost Data, 2001

2001-01-01

177

Multispectral scanner optical system  

Microsoft Academic Search

An optical system for use in a multispectral scanner of the type used in video imaging devices is disclosed. Electromagnetic radiation reflected by a rotating scan mirror is focused by a concave primary telescope mirror and collimated by a second concave mirror. The collimated beam is split by a dichroic filter which transmits radiant energy in the infrared spectrum and

R. C. Stokes; N. G. Koch

1980-01-01

178

Hybrid Dispersion Laser Scanner  

PubMed Central

Laser scanning technology is one of the most integral parts of today's scientific research, manufacturing, defense, and biomedicine. In many applications, high-speed scanning capability is essential for scanning a large area in a short time and multi-dimensional sensing of moving objects and dynamical processes with fine temporal resolution. Unfortunately, conventional laser scanners are often too slow, resulting in limited precision and utility. Here we present a new type of laser scanner that offers ?1,000 times higher scan rates than conventional state-of-the-art scanners. This method employs spatial dispersion of temporally stretched broadband optical pulses onto the target, enabling inertia-free laser scans at unprecedented scan rates of nearly 100?MHz at 800?nm. To show our scanner's broad utility, we use it to demonstrate unique and previously difficult-to-achieve capabilities in imaging, surface vibrometry, and flow cytometry at a record 2D raster scan rate of more than 100?kHz with 27,000 resolvable points. PMID:22685627

Goda, K.; Mahjoubfar, A.; Wang, C.; Fard, A.; Adam, J.; Gossett, D. R.; Ayazi, A.; Sollier, E.; Malik, O.; Chen, E.; Liu, Y.; Brown, R.; Sarkhosh, N.; Di Carlo, D.; Jalali, B.

2012-01-01

179

Optical fuel pin scanner  

DOEpatents

An optical scanner for indicia arranged in a focal plane at a cylindrical outside surface by use of an optical system including a rotatable dove prism. The dove prism transmits a rotating image of an encircled cylindrical surface area to a stationary photodiode array.

Kirchner, Tommy L. (Richland, WA); Powers, Hurshal G. (Richland, WA)

1983-01-01

180

Microwave and RF heating under noninvasive temperature measurement using magnetic resonance imaging scanner  

Microsoft Academic Search

Recent development of Magnetic Resonance Imaging (MRI) equipment enables Interventional Radiology (IVR) as diagnosis and treatment under MRI usage. In this paper, a new methodology for Magnetic Resonance (MR) scanner to apply not only diagnostic equipment but for treatment one is discussed. The temperature measuring procedure under MR is to measure phase shift of T1, which is the longitudinal relaxation

Yoshio Nikawa; Akira Ishikawa

2011-01-01

181

Functional correlates of cognitive dysfunction in multiple sclerosis: A multicenter fMRI Study.  

PubMed

In this multicenter study, we applied functional magnetic resonance imaging (fMRI) to define the functional correlates of cognitive dysfunction in patients with multiple sclerosis (MS). fMRI scans during the performance of the N-back task were acquired from 42 right-handed relapsing remitting (RR) MS patients and 52 sex-matched right-handed healthy controls, studied at six European sites using 3.0 Tesla scanners. Patients with at least two abnormal (<2 standard deviations from the normative values) neuropsychological tests at a standardized evaluation were considered cognitively impaired (CI). FMRI data were analyzed using the SPM8 software, modeling regions showing load-dependent activations/deactivations with increasing task difficulty. Twenty (47%) MS patients were CI. During the N-back load condition, compared to controls and CI patients, cognitively preserved (CP) patients had increased recruitment of the right dorsolateral prefrontal cortex. As a function of increasing task difficulty, CI MS patients had reduced activations of several areas located in the fronto-parieto-temporal lobes as well as reduced deactivations of regions which are part of the default mode network compared to the other two groups. Significant correlations were found between abnormal fMRI patterns of activations and deactivations and behavioral measures, cognitive performance, and brain T2 and T1 lesion volumes. This multicenter study supports the theory that a preserved fMRI activity of the frontal lobe is associated with a better cognitive profile in MS patients. It also indicates the feasibility of fMRI to monitor disease evolution and treatment effects in future studies. Hum Brain Mapp 35:5799-5814, 2014. 2014 Wiley Periodicals, Inc. PMID:25045065

Rocca, Maria A; Valsasina, Paola; Hulst, Hanneke E; Abdel-Aziz, Khaled; Enzinger, Christian; Gallo, Antonio; Pareto, Debora; Riccitelli, Gianna; Muhlert, Nils; Ciccarelli, Olga; Barkhof, Frederik; Fazekas, Franz; Tedeschi, Gioacchino; Arvalo, Maria J; Filippi, Massimo

2014-12-01

182

TESLA Report 2003-08 Cavity control system  

E-print Network

TESLA Report 2003-08 Cavity control system essential modeling for TESLA linear accelerator Tomasz of Technology, Poland Stefan Simrock DESY, TESLA, Hamburg, Germany ABSTRACT The pioneering TESLA linear are proposed. Keywords: TESLA, free electron laser, accelerator, high power microwave cavity, vector and phasor

183

The Photon Collider at Tesla  

Microsoft Academic Search

High energy photon colliders (gammagamma,gammae) are based on e-e- linear colliders where high energy photons are produced using Compton scattering of laser light on high energy electrons just before the interaction point. This paper is a part of the Technical Design Report of the linear collider TESLA.1 Physics program, possible parameters and some technical aspects of the photon collider at

B. Badelek; C. Blchinger; J. Blmlein; E. Boos; R. Brinkmann; H. Burkhardt; P. Bussey; C. Carimalo; J. Chyla; A. K. ifti; W. Decking; A. de Roeck; V. Fadin; M. Ferrario; A. Finch; H. Fraas; F. Franke; M. Galynskii; A. Gamp; I. Ginzburg; R. Godbole; D. S. Gorbunov; G. Gounaris; K. Hagiwara; L. Han; R.-D. Heuer; C. Heusch; J. Illana; V. Ilyin; P. Jankowski; Y. Jiang; G. Jikia; L. Jnsson; M. Kalachnikow; F. Kapusta; R. Klanner; M. Klassen; K. Kobayashi; T. Kon; G. Kotkin; M. Krmer; M. Krawczyk; Y. P. Kuang; E. Kuraev; J. Kwiecinski; M. Leenen; M. Levchuk; W. F. Ma; H. Martyn; T. Mayer; M. Melles; D. J. Miller; S. Mtingwa; M. Mhlleitner; B. Muryn; P. V. Nickles; R. Orava; G. Pancheri; A. Penin; A. Potylitsyn; P. Poulose; T. Quast; P. Raimondi; H. Redlin; F. Richard; S. D. Rindani; T. Rizzo; E. Saldin; W. Sandner; H. Schnnagel; E. Schneidmiller; H. J. Schreiber; S. Schreiber; K. P. Schler; V. Serbo; A. Seryi; R. Shanidze; W. da Silva; S. Sldner-Rembold; M. Spira; A. M. Stasto; S. Sultansoy; T. Takahashi; V. Telnov; A. Tkabladze; D. Trines; A. Undrus; A. Wagner; N. Walker; I. Watanabe; T. Wengler; I. Will; S. Wipf; . Yavas; K. Yokoya; M. Yurkov; A. F. Zarnecki; P. Zerwas; F. Zomer

2004-01-01

184

The legacy of Nikola Tesla  

Microsoft Academic Search

Electrical power supply has grown enormously during this century. In 1950 the total capacity of generators producing electricity\\u000a in India was less than 3000 MW. Today, the power generating capacity is around 120,000 MW. The polyphase AC system, which\\u000a is to a large extent the legacy of Nikola Tesla, is central to all power generation. Power systems these days are

D P Sen Gupta

2007-01-01

185

High throughput optical scanner  

DOEpatents

A scanning apparatus is provided to obtain automated, rapid and sensitive scanning of substrate fluorescence, optical density or phosphorescence. The scanner uses a constant path length optical train, which enables the combination of a moving beam for high speed scanning with phase-sensitive detection for noise reduction, comprising a light source, a scanning mirror to receive light from the light source and sweep it across a steering mirror, a steering mirror to receive light from the scanning mirror and reflect it to the substrate, whereby it is swept across the substrate along a scan arc, and a photodetector to receive emitted or scattered light from the substrate, wherein the optical path length from the light source to the photodetector is substantially constant throughout the sweep across the substrate. The optical train can further include a waveguide or mirror to collect emitted or scattered light from the substrate and direct it to the photodetector. For phase-sensitive detection the light source is intensity modulated and the detector is connected to phase-sensitive detection electronics. A scanner using a substrate translator is also provided. For two dimensional imaging the substrate is translated in one dimension while the scanning mirror scans the beam in a second dimension. For a high throughput scanner, stacks of substrates are loaded onto a conveyor belt from a tray feeder.

Basiji, David A. (Seattle, WA); van den Engh, Gerrit J. (Seattle, WA)

2001-01-01

186

LCPHSM200060TESLA 29th December 2000  

E-print Network

LC­PHSM­2000­60­TESLA 29th December 2000 Measurement of the Differential Luminosity using Bhabha events in the Forward­Tracking region at TESLA K. M¨onig DESY­Zeuthen Abstract For most analyses at an e at TESLA is studied. #12; 1 Introduction One of the few unpleasant features of an e + e \\Gamma ­linear

187

TESLA Technical Design Report Executive Summary  

E-print Network

TESLA Technical Design Report PART I Executive Summary March 2001 Editors: F.Richard, J.R.Schneider, D.Trines, A.Wagner #12;#12;Dedicated to the memory of Bjørn H. Wiik (1937-1999) #12;#12;TESLA ­ A Summary This report describes the scientific aims and potential as well as the technical de- sign of TESLA

188

Correlation of histological findings from a large ciliochoroidal melanoma with CT perfusion and 3T MRI dynamic enhancement studies  

PubMed Central

Background The initial use of a 64-slice computed tomography (CT) scanner for obtaining quantitative perfusion data from a large ciliochoroidal melanoma, and correlation with 3T magnetic resonance imaging (MRI) dynamic enhancement and tumor histology. Methods The CT perfusion scan was performed using 80 kVp, 250 mA and 1-sec rotation time for 40 sec. The analysis was performed using commercial perfusion analysis software with a prototype 3-dimensional motion correction tool. Dynamic contrast-enhanced 3-Tesla MRI measured the kinetics of enhancement to estimate the vascular permeability. The time-dependent enhancement patterns were obtained using the average signal intensity using Functool analysis software. The involved globe was enucleated and microscopic evaluation of the tumor was performed. Results The perfusion parameters blood flow, blood volume and permeability surface area product in the affected eye determined by CT perfusion analysis were 118 ml/100 ml/min, 11.3 ml/100 ml and 48 ml/100 ml/min. Dynamic MRI enhancement showed maximal intensity increase of 111%. The neoplasm was a ciliochoroidal spindle cell melanoma which was mitotically active (13 mitoses/40 hpf). Vascular loops and arcades were present throughout the tumor. The patient developed metastases within 9 months of presentation. Conclusion Quantitative CT perfusion analysis of ocular tumors is feasible with motion correction software. PMID:19668716

Pulido, Jose S; Campeau, Norbert G; Klotz, Ernst; Primak, Andrew N; Saba, Osama; Gunduz, Kaan; Cantrill, Herbert; Salomo, Diva; McCollough, Cynthia H

2008-01-01

189

Beyond blood brain barrier breakdown - in vivo detection of occult neuroinflammatory foci by magnetic nanoparticles in high field MRI  

PubMed Central

Background Gadopentate dimeglumine (Gd-DTPA) enhanced magnetic resonance imaging (MRI) is widely applied for the visualization of blood brain barrier (BBB) breakdown in multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE). Recently, the potential of magnetic nanoparticles to detect macrophage infiltration by MRI was demonstrated. We here investigated a new class of very small superparamagnetic iron oxide particles (VSOP) as novel contrast medium in murine adoptive-transfer EAE. Methods EAE was induced in 17 mice via transfer of proteolipid protein specific T cells. MR images were obtained before and after application of Gd-DTPA and VSOP on a 7 Tesla rodent MR scanner. The enhancement pattern of the two contrast agents was compared, and correlated to histology, including Prussian Blue staining for VSOP detection and immunofluorescent staining against IBA-1 to identify macrophages/microglia. Results Both contrast media depicted BBB breakdown in 42 lesions, although differing in plaques appearances and shapes. Furthermore, 13 lesions could be exclusively visualized by VSOP. In the subsequent histological analysis, VSOP was localized to microglia/macrophages, and also diffusely dispersed within the extracellular matrix. Conclusion VSOP showed a higher sensitivity in detecting BBB alterations compared to Gd-DTPA enhanced MRI, providing complementary information of macrophage/microglia activity in inflammatory plaques that has not been visualized by conventional means. PMID:19660125

Tysiak, Eva; Asbach, Patrick; Aktas, Orhan; Waiczies, Helmar; Smyth, Maureen; Schnorr, Joerg; Taupitz, Matthias; Wuerfel, Jens

2009-01-01

190

fMRI pain activation in the periaqueductal gray in healthy volunteers during the cold pressor test.  

PubMed

The periaqueductal gray (PAG), a brain area belonging to the descending pain modulatory system, plays a crucial role in pain perception. Little information is available on the relationship between PAG activation and perceived pain intensity. In this study, we acquired functional magnetic resonance imaging (fMRI) scans from the PAG during the cold pressor test, a model for tonic pain, in 12 healthy volunteers. fMRI data were acquired with a 12-channel head-coil and a 3-Tesla scanner and analyzed with Statistical Parametric Mapping (SPM8) software. During the cold pressor test, fMRI showed significant activation clusters in pain-related brain areas: bilateral middle and superior frontal gyrus, anterior cingulate cortex and thalamus, left insula, right inferior frontal gyrus, left inferior temporal gyrus and in the bilateral PAG (cluster level corrected threshold p<0.05). PAG activation correlated directly with the pain threshold and inversely with the participant's perceived pain intensity (cluster level corrected threshold (p<0.05). The cold pressor test consistently activated the PAG as well as other pain-related areas in the brain. Our study, showing that the greater the PAG activation the higher the pain threshold and the weaker the pain intensity perceived, highlights the key role of the PAG in inhibiting the pain afferent pathway function. Our findings might be useful for neuroimaging studies investigating PAG activation in patients with chronic idiopathic pain conditions possibly related to dysfunction in the descending pain modulatory system. PMID:24468081

La Cesa, S; Tinelli, E; Toschi, N; Di Stefano, G; Collorone, S; Aceti, A; Francia, A; Cruccu, G; Truini, A; Caramia, F

2014-04-01

191

TESLA Report 2004-10 Software layer for FPGA-based TESLA cavity control system  

E-print Network

TESLA Report 2004-10 Software layer for FPGA-based TESLA cavity control system (part I) Waldemar of hardware communication based on Internal Interface (II) technology. Such a solution was used for superconducting Cavity Controller and Simulator (SIMCON) for the TESLA experiment in DESY (Hamburg). A number

192

Tesla Report 2003-22 FPGA based Cavity Simulator for Tesla Test Facility  

E-print Network

Tesla Report 2003-22 FPGA based Cavity Simulator for Tesla Test Facility Wojciech M. Zabolotnya Simrockd, Ryszard Romaniuka aInstitute of Electronic Systems, Warsaw University of Technology, ul: TESLA, DESY, FPGA, DSP, analog systems simulation, high energy physics, superconducting accelerating

193

Application of 3.0 Tesla Magnetic Resonance Imaging for Diagnosis in the Orthotopic Nude Mouse Model of Pancreatic Cancer  

PubMed Central

The aim of this study was to successfully establish an orthotopic murine model using two different human pancreatic adenocarcinoma cell lines and to propose a 3.0 tesla MRI protocol for noninvasive characterization of this model. SW1990 and MIAPaca-2 tumor cells were injected into the pancreas of BALB/C nu/nu mice. Tumor growth rate and morphological information were assessed by 3.0 tesla MRI (T1WI, T2WI and DCE-MRI) and immunohistology. Proliferation of SW1990 was significantly faster than that of MIAPaca-2 (P=0.000), but MIAPaca-2 mice had a significantly shorter survival than SW1990 mice (41 days and 44 days respectively, P=0.027). MRI could reliably monitor tumor growth in both cell lines: the tumors exhibiting a spherical growth pattern showed a high-intensity signal, and the SW1990 group developed significantly larger tumors compared with the MIAPaCa-2 group. There were no statistical differences between the two groups in which tumor size was assessed using electronic calipers and an MRI scan (P=0.680). Both tumors showed a slow gradual enhancement pattern. Immunohistochemistry demonstrated tumor tissues showing high expression of Ki-67. This model closely mimics human pancreatic cancer and permits monitoring of tumor growth and morphological information by noninvasive 3.0 tesla MRI studies reducing the number of mice required. PMID:25048266

Wu, Li; Wang, Chen; Yao, Xiuzhong; Liu, Kai; Xu, Yanjun; Zhang, Haitao; Fu, Caixia; Wang, Xiaolin; Li, Yingyi

2014-01-01

194

Application of 3.0 tesla magnetic resonance imaging for diagnosis in the orthotopic nude mouse model of pancreatic cancer.  

PubMed

The aim of this study was to successfully establish an orthotopic murine model using two different human pancreatic adenocarcinoma cell lines and to propose a 3.0 tesla MRI protocol for noninvasive characterization of this model. SW1990 and MIAPaca-2 tumor cells were injected into the pancreas of BALB/C nu/nu mice. Tumor growth rate and morphological information were assessed by 3.0 tesla MRI (T1WI, T2WI and DCE-MRI) and immunohistology. Proliferation of SW1990 was significantly faster than that of MIAPaca-2 (P=0.000), but MIAPaca-2 mice had a significantly shorter survival than SW1990 mice (41 days and 44 days respectively, P=0.027). MRI could reliably monitor tumor growth in both cell lines: the tumors exhibiting a spherical growth pattern showed a high-intensity signal, and the SW1990 group developed significantly larger tumors compared with the MIAPaCa-2 group. There were no statistical differences between the two groups in which tumor size was assessed using electronic calipers and an MRI scan (P=0.680). Both tumors showed a slow gradual enhancement pattern. Immunohistochemistry demonstrated tumor tissues showing high expression of Ki-67. This model closely mimics human pancreatic cancer and permits monitoring of tumor growth and morphological information by noninvasive 3.0 tesla MRI studies reducing the number of mice required. PMID:25048266

Wu, Li; Wang, Chen; Yao, Xiuzhong; Liu, Kai; Xu, Yanjun; Zhang, Haitao; Fu, Caixia; Wang, Xiaolin; Li, Yingyi

2014-10-30

195

Effect of the static magnetic field of the MR-scanner on ERPs: Evaluation of visual, cognitive and motor potentials  

E-print Network

Effect of the static magnetic field of the MR-scanner on ERPs: Evaluation of visual, cognitive, B-3000 Leuven, Belgium d Katholieke Universiteit Leuven, Department of Pediatric Neurology, B-3000 of the static magnetic field of the MR-scanner on ERPs extracted from simultaneous EEG�fMRI recordings

196

MRI Evaluation of Spinal Length and Vertebral Body Angle During Loading with a Spinal Compression Harness  

NASA Technical Reports Server (NTRS)

Weight bearing by the spinal column during upright posture often plays a role in the common problem of low back pain. Therefore, we developed a non-ferromagnetic spinal compression harness to enable MRI investigations of the spinal column during axial loading. Human subjects were fitted with a Nest and a footplate which were connected by adjustable straps to an analog load cell. MRI scans of human subjects (5 males and 1 female with age range of 27-53 yrs) during loaded and unloaded conditions were accomplished with a 1.5 Tesla GE Signa scanner. Studies of two subjects undergoing sequentially increasing spinal loads revealed significant decreases (r(sup 2) = 0.852) in spinal length between T4 and L5 culminating in a 1.5 to 2% length decrease during loading with 75% body weight. Sagittal vertebral body angles of four subjects placed under a constant 50% body weight load for one hour demonstrated increased lordotic and kyphotic curvatures. In the lumbar spine, the L2 vertebral body experienced the greatest angular change (-3 deg. to -5 deg.) in most subjects while in the thoracic spine, T4 angles increased from the unloaded state by +2 deg. to +9 deg. Overall, our studies demonstrate: 1) a progressive, although surprisingly small, decrease in spinal length with increasing load and 2) relatively large changes in spinal column angulation with 50% body weight.

Campbell, James A.; Hargens, Alan R.; Murthy, G.; Ballard, R. E.; Watenpaugh, D. E.; Hargens, Alan, R.; Sanchez, E.; Yang, C.; Mitsui, I.; Schwandt, D.; Fechner, K. P.; Holton, Emily M. (Technical Monitor)

1998-01-01

197

TESLA Report 2005-22 Internal Interface  

E-print Network

- 1/63 - TESLA Report 2005-22 Internal Interface I/O communication with FPGA circuits and hardware of Electronic Systems, Warsaw University of Technology, ELHEP Laboratory Nowowiejska 15/19, 00-665 Warsaw for Compact Muon Solenoid (CMS) in CERN [15], · TESLA Low Level RF Control electronics for TTF II and VUV FEL

198

LCPHSM19992TESLA 7th September 1999  

E-print Network

LC­PHSM­1999­2­TESLA 7th September 1999 Electroweak Physics at a Linear Collider Z­factory K. M?onig DESY­Zeuthen Abstract Assuming that a linear collider like TESLA can run with polarised electron one should be able to polarise the electrons with the same technology as at the SLC to up to 80

199

Highlights from the TESLA technical design proposal  

Microsoft Academic Search

The technical design report (TDR) of the TESLA superconducting linear collider with an integrated X-ray FEL facility, has been published in the spring of 2001 by an international collaboration. It includes a description of the high energy physics programme, a proposal for the detector, and the collider design relying on the technical results from the TESLA Test Facility (TTF). We

O. Napoly

2001-01-01

200

TESLA Report 2005-13 DOOCS environment  

E-print Network

TESLA Report 2005-13 1 DOOCS environment for FPGA-based cavity control system and control University of Technology, Nowowiejska 15/19, 00-665 Warsaw, Poland photonics@ise.pw.edu.pl ABSTRACT The paper describes the concept and realization of the DOOCS control software for FPGA- based TESLA cavity controller

201

Nikola Tesla: the man time forgot  

Microsoft Academic Search

The life and career of Nikola Tesla are described. His development of the AC motor and his battle with Thomas Edison over the use of AC versus DC (Edison was a proponent of the latter) are recounted. Experiments in which Tesla was far ahead of his time are described

J. I. Vuckovic

1990-01-01

202

Tesla - A Flash of a Genius  

Microsoft Academic Search

This book, which is entirely dedicated to the inventions of scientist Nikola Tesla, is divided into three parts: a) all the most important innovative technological creations from the alternate current to the death ray, Tesla research in fundamental physics with a particular attention to the concept of \\

M. Teodorani

2005-01-01

203

T1? MRI in Alzheimers Disease: Detection of Pathological Changes in Medial Temporal Lobe  

PubMed Central

BACKGROUND The need of an early and noninvasive diagnosis of AD requires the development of imaging-based techniques. As an alternative, the magnetic resonance image (MRI) relaxation time constant (T1? ) was measured in brains of Alzheimers disease (AD), mild-cognitive impairment (MCI), and age-matched controls in order to determine whether T1? values correlated with the neurological diagnosis. METHODS MRI was performed on AD (n = 48), MCI (n = 45), and age-matched control (n = 41), on a 1.5 Tesla Siemens clinical MRI scanner. T1? maps were generated by fitting each pixels intensity as a function of the duration of the spin-lock pulse. T1? values were calculated from the gray matter (GM) and white matter (WM) of medial temporal lobe (MTL). RESULTS GM and WM T1? values were 87.5 1.2 ms and 80.5 1.4 ms, respectively, in controls, 90.9 1.3 ms and 84.1 1.7 ms in MCI, and 91.9 .8 ms and 88.3 1.3 ms in AD cohorts. Compared to control, AD patients showed 9% increased WM T1? and 5% increased GM T1?. Compared to control, MCI individuals showed 4% increased T1? both in WM and GM. A 5% increased T1? was found in WM of AD over MCI. CONCLUSION The increased T1? in WM and GM of MTL in AD may be associated with the pathological changes that are not evident on conventional MRI. PMID:20331502

Haris, Mohammad; Singh, Anup; Cai, Kejia; McArdle, Erin; Fenty, Matthew; Davatzikos, Christos; Trojanowski, John Q.; Melhem, Elias R.; Clark, Christopher M.; Borthakur, Arijitt

2010-01-01

204

High Field Atherosclerotic Plaque MRI  

PubMed Central

Manifestations of atherosclerotic plaque in different arterial beds range from perfusion deficits to overt ischemia such as stroke and myocardial infarction. Atherosclerotic plaque composition is known to be associated with its propensity to rupture and cause vascular events. MRI of atherosclerotic plaque using clinical 1.5T scanners can detect plaque composition. Plaque MRI at higher field strengths offers both opportunities and challenges to improving the high spatial-resolution and contrast required for this type of imaging. This article summarizes the technological requirements required for high field plaque MRI and its application in detecting plaque components. PMID:22548932

Yuan, Chun; Wang, Jinnan; Balu, Niranjan

2012-01-01

205

MRI driven magnetic microswimmers  

PubMed Central

Capsule endoscopy is a promising technique for diagnosing diseases in the digestive system. Here we design and characterize a miniature swimming mechanism that uses the magnetic fields of the MRI for both propulsion and wireless powering of the capsule. Our method uses both the static and the radio frequency (RF) magnetic fields inherently available in MRI to generate a propulsive force. Our study focuses on the evaluation of the propulsive force for different swimming tails and experimental estimation of the parameters that influence its magnitude. We have found that an approximately 20 mm long, 5 mm wide swimming tail is capable of producing 0.21 mN propulsive force in water when driven by a 20 Hz signal providing 0.85 mW power and the tail located within the homogeneous field of a 3 T MRI scanner. We also analyze the parallel operation of the swimming mechanism and the scanner imaging. We characterize the size of artifacts caused by the propulsion system. We show that while the magnetic micro swimmer is propelling the capsule endoscope, the operator can locate the capsule on the image of an interventional scene without being obscured by significant artifacts. Although this swimming method does not scale down favorably, the high magnetic field of the MRI allows self propulsion speed on the order of several millimeter per second and can propel an endoscopic capsule in the stomach. PMID:22037673

Jakab, Peter; Szekely, Gabor; Hata, Nobuhiko

2013-01-01

206

MRI driven magnetic microswimmers.  

PubMed

Capsule endoscopy is a promising technique for diagnosing diseases in the digestive system. Here we design and characterize a miniature swimming mechanism that uses the magnetic fields of the MRI for both propulsion and wireless powering of the capsule. Our method uses both the static and the radio frequency (RF) magnetic fields inherently available in MRI to generate a propulsive force. Our study focuses on the evaluation of the propulsive force for different swimming tails and experimental estimation of the parameters that influence its magnitude. We have found that an approximately 20mm long, 5mm wide swimming tail is capable of producing 0.21 mN propulsive force in water when driven by a 20Hz signal providing 0.85mW power and the tail located within the homogeneous field of a 3T MRI scanner. We also analyze the parallel operation of the swimming mechanism and the scanner imaging. We characterize the size of artifacts caused by the propulsion system. We show that while the magnetic micro swimmer is propelling the capsule endoscope, the operator can locate the capsule on the image of an interventional scene without being obscured by significant artifacts. Although this swimming method does not scale down favorably, the high magnetic field of the MRI allows self propulsion speed on the order of several millimeter per second and can propel an endoscopic capsule in the stomach. PMID:22037673

Ksa, Gbor; Jakab, Pter; Szkely, Gbor; Hata, Nobuhiko

2012-02-01

207

Multispectral scanner optical system  

NASA Technical Reports Server (NTRS)

An optical system for use in a multispectral scanner of the type used in video imaging devices is disclosed. Electromagnetic radiation reflected by a rotating scan mirror is focused by a concave primary telescope mirror and collimated by a second concave mirror. The collimated beam is split by a dichroic filter which transmits radiant energy in the infrared spectrum and reflects visible and near infrared energy. The long wavelength beam is filtered and focused on an infrared detector positioned in a cryogenic environment. The short wavelength beam is dispersed by a pair of prisms, then projected on an array of detectors also mounted in a cryogenic environment and oriented at an angle relative to the optical path of the dispersed short wavelength beam.

Stokes, R. C.; Koch, N. G. (inventors)

1980-01-01

208

TESLA Note 2003-06 Cavity Control System  

E-print Network

, Warsaw University of Technology Stefan Simrock TESLA, DESY, Hamburg ABSTRACT The cavity control systemTESLA Note 2003-06 Cavity Control System Advanced Modeling and Simulations For TESLA Linear for the TESLA - TeV­Energy Superconducting Linear Accelerator project is initially introduced. The elementary

209

Multi-Level TESLA: Broadcast Authentication for Distributed Sensor Networks  

E-print Network

Multi-Level µTESLA: Broadcast Authentication for Distributed Sensor Networks DONGGANG LIU and PENG named multi-level µTESLA based on µTESLA, a broadcast authentication protocol whose scalability is limited by its unicast-based initial parameter distribution. Multi-level µTESLA satisfies several nice

Ning, Peng

210

First Thoughts on Commissioning of the TESLA Compiled by P. Castro for the TESLA commissioning study group.  

E-print Network

First Thoughts on Commissioning of the TESLA Collider Compiled by P. Castro for the TESLA commissioning study group. September 6, 2002 Abstract The TESLA collider[1] is a large scale project be included in the plans of the construction and installation work of the TESLA collider. A working group

211

3-Tesla MRI Response to TACE in HCC (Liver Cancer)  

ClinicalTrials.gov

Adult Primary Hepatocellular Carcinoma; Advanced Adult Primary Liver Cancer; Localized Resectable Adult Primary Liver Cancer; Localized Unresectable Adult Primary Liver Cancer; Stage A Adult Primary Liver Cancer (BCLC); Stage B Adult Primary Liver Cancer (BCLC)

2014-03-20

212

Sentence Reading: A Functional MRI Study at 4 Tesla  

Microsoft Academic Search

In this study, changes in blood oxygenation and volume were monitored while monolingual right-handed subjects read English sentences. Our results confirm the role of the left peri-sylvian cortex in language processing. Interestingly, individual subject analyses reveal a pattern of activation characterized by several small, limited patches rather than a few large, anatomically well-circumscribed centers. Between-subject analyses confirm a lateralized pattern

D. Bavelier; D. Corina; P. Jezzard; S. Padmanabhan; V. P. Clark; A. Karni; A. Prinster; A. Braun; A. Lalwani; J. P. Rauschecker; R. Turner; H. Neville

1997-01-01

213

[Nikola Tesla: flashes of inspiration].  

PubMed

Nikola Tesla (1856-1943) was one of the greatest inventors in history and a key player in the revolution that led to the large-scale use of electricity. He also made important contributions to such diverse fields as x-rays, remote control, radio, the theory of consciousness or electromagnetism. In his honour, the international unit of magnetic induction was named after him. Yet, his fame is scarce in comparison with that of other inventors of the time, such as Edison, with whom he had several heated arguments. He was a rather odd, reserved person who lived for his inventions, the ideas for which came to him in moments of inspiration. In his autobiography he relates these flashes with a number of neuropsychiatric manifestations, which can be seen to include migraine auras, synaesthesiae, obsessions and compulsions. PMID:23307357

Villarejo-Galende, Albero; Herrero-San Martn, Alejandro

2013-01-16

214

3Tesla versus 1.5Tesla Magnetic Resonance Diffusion and Perfusion Imaging in Hyperacute Ischemic Stroke  

Microsoft Academic Search

Background: Clinical 3-tesla magnetic resonance imaging systems are becoming widespread. No studies have examined differences between 1.5-tesla and 3-tesla imaging for the assessment of hyperacute ischemic stroke (<6 h from symptom onset). Our objective was to compare 1.5-tesla and 3-tesla diffusion and perfusion imaging for hyperacute stroke using optimized protocols. Methods: Three patients or their surrogate provided informed consent. Diffusion-weighted

Robert K. Kosior; Caitlin J. Wright; Jayme C. Kosior; Carol Kenney; James N. Scott; Richard Frayne; Michael D. Hill

2007-01-01

215

Medical facial surface scanner  

NASA Astrophysics Data System (ADS)

Optical, non-contact three-dimensional range surface digitizers are employed in the 360-degree examination of object surfaces, especially the heads and faces of individuals. The resultant 3- D surface data is suitable for computer graphics display and manipulation, for numerically controlled object replications, or for further processing such as surface measurement extraction. We employed a scanner with a basic active sensor element consisting of a synchronized pattern projector employing flashtubes that illuminate a surface, with a CID camera to detect, digitize, and transmit the sequence of 24 images (per camera) to a digital image processor for surface triangulation, calibration, and fusion into a single surface description of the headform. A major feature of this unit is its use of multiple (typically 6) stationary active sensor elements, with efficient calibration algorithms that achieve nearly seamless superposition of overlapping surface segments seen by individual cameras. The result is accurate and complete coverage of complex contoured surfaces. Application of this system to digitization of the human head in the planning and evaluation of facial plastic surgery is presented.

Vannier, Michael W.; Bhatia, Gulab H.; Commean, Paul K.; Pilgram, Thomas K.; Brunsden, Barry S.

1992-05-01

216

MRI artefacts after Bonebridge implantation.  

PubMed

The new transcutaneous bone conduction implant (BCI) Bonebridge (BB, MED-EL) allows the skin to remain intact and therefore overcomes some issues related to percutaneous systems, such as skin reaction around the external screw and cosmetic complaints. According to manufacturer, BB is MRI conditional up to 1,5 Tesla (T). The artefact of the neurocranium after BB implantation is extensive as shown in the present report. This has to be taken into account when patients suffering conductive, mixed or single-sided hearing loss with candidacy for a BCI are counselled. In patients with comorbid intracranial tumour or other diseases of the brain that require imaging control scans with MRI percutaneous, BCI should be the implant of choice considering the very small artefact of the percutaneous screw in MRI. PMID:24639341

Steinmetz, C; Mader, I; Arndt, S; Aschendorff, A; Laszig, R; Hassepass, F

2014-07-01

217

Linear Regression of BMD Scanners  

NSDL National Science Digital Library

Students complete an exercise showing logarithmic relationships and examine how to find the linear regression of data that does not seem linear upon initial examination. They relate number of BMD scanners to time.

Vu Bioengineering Ret Program

218

MSS D Multispectral Scanner System  

NASA Technical Reports Server (NTRS)

The development and acceptance testing of the 4-band Multispectral Scanners to be flown on LANDSAT D and LANDSAT D Earth resources satellites are summarized. Emphasis is placed on the acceptance test phase of the program. Test history and acceptance test algorithms are discussed. Trend data of all the key performance parameters are included and discussed separately for each of the two multispectral scanner instruments. Anomalies encountered and their resolutions are included.

Lauletta, A. M.; Johnson, R. L.; Brinkman, K. L. (principal investigators)

1982-01-01

219

Pilot Study Investigating the Effect of the Static Magnetic Field From a 9.4-T MRI on the  

E-print Network

Pilot Study Investigating the Effect of the Static Magnetic Field From a 9.4-T MRI exposure to a strong, new generation 9.4-T Magnetic Resonance Imaging (MRI) scanner. Method: Six MRI hospitals are of 1.5 T or 3.0 T. Our institution has a 9.4-T human Mag- netic Resonance Imaging (MRI) scan

Illinois at Chicago, University of

220

Cerebral Activation During the Test of Spinal Cord Injury Severity in Children: an fMRI Methodological Study  

PubMed Central

Background: The International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) are internationally accepted to determine and classify the extent of motor and sensory impairment along with severity (ASIA Impairment Scale [AIS]) following spinal cord injury (SCI). The anorectal examination is a component of the ISNCSCI that determines injury severity. There is a void in the health care literature on the validity of the anorectal examination as an indication of SCI severity. Objective: To validate the use of functional magnetic resonance imagining (fMRI) for the purpose of classifying the severity of SCI in children. Methods: Seventeen patients, with the average age of 14.3 years, underwent 1 complete ISNCSCI examination. Subjects also underwent the anorectal portion of this exam while fMRI data were collected using a 3.0 Tesla Siemens Verio Scanner. Cortical areas of activation were analyzed for possible differences of cortical involvement between complete (AIS A) and incomplete (AIS B, C, and D) SCI subjects. Anxiety/anticipation of the test was also assessed. Results: This study established an fMRI imaging protocol that captures the cortical locations and intensity of activation during the test of sacral sparing. In addition to developing the data acquisition protocol, we also established the postacquisition preprocessing and statistical analysis parameters using SPM8. Conclusion: Preliminary findings indicate that fMRI is a useful tool in evaluating the validity of the anorectal examination in determining SCI severity. Assessment of which cortical regions are activated during the testing procedure provides an indication of which pathways are transmitting information to the brain. PMID:23671382

2013-01-01

221

3D ultrafast laser scanner  

NASA Astrophysics Data System (ADS)

Laser scanners are essential for scientific research, manufacturing, defense, and medical practice. Unfortunately, often times the speed of conventional laser scanners (e.g., galvanometric mirrors and acousto-optic deflectors) falls short for many applications, resulting in motion blur and failure to capture fast transient information. Here, we present a novel type of laser scanner that offers roughly three orders of magnitude higher scan rates than conventional methods. Our laser scanner, which we refer to as the hybrid dispersion laser scanner, performs inertia-free laser scanning by dispersing a train of broadband pulses both temporally and spatially. More specifically, each broadband pulse is temporally processed by time stretch dispersive Fourier transform and further dispersed into space by one or more diffractive elements such as prisms and gratings. As a proof-of-principle demonstration, we perform 1D line scans at a record high scan rate of 91 MHz and 2D raster scans and 3D volumetric scans at an unprecedented scan rate of 105 kHz. The method holds promise for a broad range of scientific, industrial, and biomedical applications. To show the utility of our method, we demonstrate imaging, nanometer-resolved surface vibrometry, and high-precision flow cytometry with real-time throughput that conventional laser scanners cannot offer due to their low scan rates.

Mahjoubfar, A.; Goda, K.; Wang, C.; Fard, A.; Adam, J.; Gossett, D. R.; Ayazi, A.; Sollier, E.; Malik, O.; Chen, E.; Liu, Y.; Brown, R.; Sarkhosh, N.; Di Carlo, D.; Jalali, B.

2013-03-01

222

MRI-compatible Haptics: Strain sensing for real-time estimation of three dimensional needle deflection in MRI environments , S. Elayaperumal1  

E-print Network

7044 MRI-compatible Haptics: Strain sensing for real-time estimation of three dimensional needle deflection in MRI environments Y-L. Park1 , S. Elayaperumal1 , S. Ryu1 , B. Daniel2 , R. J. Black3 , B Corporation, Santa Clara, CA, United States Introduction Conventional closed-bore MRI scanners preclude direct

Park, Yong-Lae

223

TESLA-FEL Report 2006-01 TESLA cavity modeling and digital implementation  

E-print Network

modes are applied for the evaluation of a FPGA cavity simulator operated by a digital controller Radio Frequency, control theory, FPGA, DSP, VHDL, system simulation, cavity controller, cavity simulatorTESLA-FEL Report 2006-01 1 TESLA cavity modeling and digital implementation in FPGA technology

224

An MRI-Compatible Robotic System With Hybrid Tracking for MRI-Guided Prostate Intervention  

PubMed Central

This paper reports the development, evaluation, and first clinical trials of the access to the prostate tissue (APT) II systema scanner independent system for magnetic resonance imaging (MRI)-guided transrectal prostate interventions. The system utilizes novel manipulator mechanics employing a steerable needle channel and a novel six degree-of-freedom hybrid tracking method, comprising passive fiducial tracking for initial registration and subsequent incremental motion measurements. Targeting accuracy of the system in prostate phantom experiments and two clinical human-subject procedures is shown to compare favorably with existing systems using passive and active tracking methods. The portable design of the APT II system, using only standard MRI image sequences and minimal custom scanner interfacing, allows the system to be easily used on different MRI scanners. PMID:22009867

Krieger, Axel; Iordachita, Iulian I.; Guion, Peter; Singh, Anurag K.; Kaushal, Aradhana; Menard, Cynthia; Pinto, Peter A.; Camphausen, Kevin; Fichtinger, Gabor

2012-01-01

225

4 Nuclear Magnetic Resonance and MRI February 26, 2008  

E-print Network

that many nuclei have intrinsic angular momentum and magnetic moments ­ this is true of the ground states materials. The proton has a magnetic moment of µp = 1.409 ? 10-26 joules per tesla, and the splitting4 Nuclear Magnetic Resonance and MRI February 26, 2008 The technique of nuclear magnetic resonance

Thouless, David

226

MRI in Diagnosis of a Giant Prostatic Utricle  

PubMed Central

A prostatic utricle cyst is an epithelial lined diverticulum arising from the prostatic urethra and usually asymptomatic when small. When enlarged, it may be symptomatic and is typically accompanied by hypospadias. We present a case of a markedly enlarged prostatic utricle in a neonate without hypospadias, demonstrated on voiding cystourethrography (VCUG), ultrasound, and 1.5 Tesla MRI. PMID:25133006

Schey, William

2014-01-01

227

Effect of 1. 5 tesla nuclear magnetic resonance imaging scanner on implanted permanent pacemakers  

Microsoft Academic Search

Patients with a permanent pacemaker are currently restricted from diagnostic nuclear magnetic resonance (NMR) imaging because of potential adverse effects on the pacemaker by the magnet. Previous work has shown that NMR imaging will result in asynchronous pacing of the pulse generator within a given distance of the magnet. The radiofrequency signal generated by the system may also result in

David L. Hayes; David R. Holmes Jr.; Joel E. Gray

1987-01-01

228

Blood Flow and Anatomical MRI in a Mouse Model of Retinitis PigmentosaAQ1  

E-print Network

associated with retinal degenera- tion in vivo. Clinical examinations of RP include digital fundus labeling MRI method to image changes in retinal and choroidal blood flow (BF) and anatomical thickness scanner. Anatomical MRI was acquired, and quantitative BF was imaged using arterial spin labeling MRI

Duong, Timothy Q.

229

Department of BioEngineering Spring 2013 MRI-Compatible Smoke Delivery System  

E-print Network

required. Created a safe and effective way to smoke an electronic cigarette in an MRI scanner #12; that allows the person to smoke the cigarette in the MRI that contains no ferrous materials, evacuates all.00-$100.00. The costs include E-cigarettes and tubing Less than 20 minute set up in MRI room Minimal manufacturing

Demirel, Melik C.

230

Multispectral Scanner for Monitoring Plants  

NASA Technical Reports Server (NTRS)

A multispectral scanner has been adapted to capture spectral images of living plants under various types of illumination for purposes of monitoring the health of, or monitoring the transfer of genes into, the plants. In a health-monitoring application, the plants are illuminated with full-spectrum visible and near infrared light and the scanner is used to acquire a reflected-light spectral signature known to be indicative of the health of the plants. In a gene-transfer- monitoring application, the plants are illuminated with blue or ultraviolet light and the scanner is used to capture fluorescence images from a green fluorescent protein (GFP) that is expressed as result of the gene transfer. The choice of wavelength of the illumination and the wavelength of the fluorescence to be monitored depends on the specific GFP.

Gat, Nahum

2004-01-01

231

Design and scaling of microscale Tesla turbines  

NASA Astrophysics Data System (ADS)

We report on the scaling properties and loss mechanisms of Tesla turbines and provide design recommendations for scaling such turbines to the millimeter scale. Specifically, we provide design, fabrication and experimental data for a low-pressure head hydro Tesla micro-turbine. We derive the analytical turbine performance for incompressible flow and then develop a more detailed model that predicts experimental performance by including a variety of loss mechanisms. We report the correlation between them and the experimental results. Turbines with 1 cm rotors, 36% peak efficiency (at 2 cm3 s-1 flow) and 45 mW unloaded peak power (at 12 cm3 s-1 flow) are demonstrated. We analyze the causes for head loss and shaft power loss and derive constraints on turbine design. We then analyze the effect of scaling down on turbine efficiency, power density and rotor revolutions/min. Based on the analysis, we make recommendations for the design of 1 mm microscale Tesla turbines.

Krishnan, Vedavalli G.; Romanin, Vince; Carey, Van P.; Maharbiz, Michel M.

2013-12-01

232

Mental Rotation Studied by Functional Magnetic Resonance Imaging at High Field (4 Tesla): Performance and Cortical Activation  

Microsoft Academic Search

We studied the performance and cortical activation patterns during a mental rotation task (Shepard & Metzler, 1971) using functional magnetic resonance imaging (fMlU) at high field (4 Tesla). Twenty-four human subjects were imaged (fMRI group), whereas six additional subjects performed the task without being imaged (control group). All subjects were shown pairs of perspective drawings of 31, objects and asked

Georgios A. Tagaris; Seong-Gi Kim; John P. Strupp; Peter Andersen; Kamil U??urbil; Apostolos P. Georgopoulos

1997-01-01

233

Use of a radio frequency shield during 1.5 and 3.0 Tesla magnetic resonance imaging: experimental evaluation  

PubMed Central

Radiofrequency (RF) shields have been recently developed for the purpose of shielding portions of the patients body during magnetic resonance imaging (MRI) examinations. We present an experimental evaluation of a commercially available RF shield in the MRI environment. All tests were performed on 1.5 T and 3.0 T clinical MRI scanners. The tests were repeated with and without the RF shield present in the bore, for comparison. Effects of the shield, placed within the scanner bore, on the RF fields generated by the scanner were measured directly using tuned pick-up coils. Attenuation, by as much as 35 dB, of RF field power was found inside the RF shield. These results were supported by temperature measurements of metallic leads placed inside the shield, in which no measurable RF heating was found. In addition, there was a small, simultaneous detectable increase (?1 dB) of RF power just outside the edges of the shield. For these particular scanners, the autocalibrated RF power levels were reduced for scan locations prescribed just outside the edges of the shield, which corresponded with estimations based on the pick-up coil measurements. Additionally, no significant heating during MRI scanning was observed on the shield surface. The impact of the RF shield on the RF fields inside the magnet bore is likely to be dependent on the particular model of the RF shield or the MRI scanner. These results suggest that the RF shield could be a valuable tool for clinical MRI practices. PMID:25378957

Favazza, Christopher P; King, Deirdre M; Edmonson, Heidi A; Felmlee, Joel P; Rossman, Phillip J; Hangiandreou, Nicholas J; Watson, Robert E; Gorny, Krzysztof R

2014-01-01

234

Consistency of breast density measured from the same women in four different MR scanners  

PubMed Central

Purpose: To compare the breast volume (BV), fibroglandular tissue volume (FV), and percent density (PD) measured from breast MRI of the same women using four different MR scanners. Methods: The study was performed in 34 healthy Asian volunteers using two 1.5T (GE and Siemens) and two 3T (GE and Philips) MR scanners. The BV, FV, and PD were measured on nonfat-suppressed T1-weighted images using a comprehensive computer algorithm-based segmentation method. The scanner-to-scanner measurement difference, and the coefficient of variation (CV) among the four scanners were calculated. The measurement variation between two density morphological patterns presenting as the central type and the intermingled type was separately analyzed and compared. Results: All four scanners provided satisfactory image quality allowing for successful completion of the segmentation processes. The measured parameters between each pair of MR scanners were highly correlated, with R2 ? 0.95 for BV, R2 ? 0.99 for FV, and R2 ? 0.97 for PD in all comparisons. The mean percent differences between each pair of scanners were 5.9%7.8% for BV, 5.3%6.5% for FV, 4.3%7.3% for PD; with the overall CV of 5.8% for BV, 4.8% for FV, and 4.9% for PD. The variation of FV was smaller in the central type than in the intermingled type (p = 0.04). Conclusions: The results showed that the variation of FV and PD measured from four different MR scanners is around 5%, suggesting the parameters measured using different scanners can be used for a combined analysis in a multicenter study. PMID:22894415

Chen, Jeon-Hor; Chan, Siwa; Liu, Yi-Jui; Yeh, Dah-Cherng; Chang, Chih-Kai; Chen, Li-Kuang; Pan, Wei-Fan; Kuo, Chih-Chen; Lin, Muqing; Chang, Daniel H. E.; Fwu, Peter T.; Su, Min-Ying

2012-01-01

235

Evaluation of slice accelerations using multiband echo planar imaging at 3 Tesla  

PubMed Central

We evaluate residual aliasing among simultaneously excited and acquired slices in slice accelerated multiband (MB) echo planar imaging (EPI). No in-plane accelerations were used in order to maximize and evaluate achievable slice acceleration factors at 3 Tesla. We propose a novel leakage (L-) factor to quantify the effects of signal leakage between simultaneously acquired slices. With a standard 32-channel receiver coil at 3 Tesla, we demonstrate that slice acceleration factors of up to eight (MB = 8) with blipped controlled aliasing in parallel imaging (CAIPI), in the absence of in-plane accelerations, can be used routinely with acceptable image quality and integrity for whole brain imaging. Spectral analyses of single-shot fMRI time series demonstrate that temporal fluctuations due to both neuronal and physiological sources were distinguishable and comparable up to slice-acceleration factors of nine (MB = 9). The increased temporal efficiency could be employed to achieve, within a given acquisition period, higher spatial resolution, increased fMRI statistical power, multiple TEs, faster sampling of temporal events in a resting state fMRI time series, increased sampling of q-space in diffusion imaging, or more quiet time during a scan. PMID:23899722

Xu, Junqian; Moeller, Steen; Auerbach, Edward J.; Strupp, John; Smith, Stephen M.; Feinberg, David A.; Yacoub, Essa; U?urbil, Kmil

2013-01-01

236

TESLA Report 2006-05 DESY Thesis 2006-000  

E-print Network

1 TESLA Report 2006-05 DESY Thesis 2006-000 WARSAW UNIVERSITY OF TECHNOLOGY Faculty of Electronics and Informational Technologies Institute of Electronic Systems ELHEP Laboratory DESY TESLA LLRF Team Rafal Pietrasik (B.Sc. Thesis in Electrical Engineering) SIMCON 3.1 LLRF System control board measurements (for TESLA

237

LCM2003045 Improved TESLA Optics and Beam Induced  

E-print Network

LC­M­2003­045 Improved TESLA Optics and Beam Induced Backgrounds Update Karsten B?u?er, DESY and Olivier Napoly, CEA/Saclay LCWS 2002, Jeju, Korea Abstract A new tesla optics with l*=5m is under development. An update is given on the simulation of the beam induced backgrounds in the TESLA detector. 1

238

Beam Dynamics Study for TESLA with the Integrated FEL  

E-print Network

Beam Dynamics Study for TESLA with the Integrated FEL V.M. Tsakanov Yerevan Physics Institute : : : : : : : : : : : : : : : : : : : : : : : 7 2.3 Conclusion 1 : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 10 3 The TESLA high based trajectory correction : : : : : : : : : : : : 22 5 Summary 25 1 #12;. 1 Introduction In the TESLA

239

Hydrodynamic Tesla Wheel Flume for Model and Prototype Testing  

E-print Network

Hydrodynamic Tesla Wheel Flume for Model and Prototype Testing Spencer Jenkins, Chris Scott, Jacob Engineering department at Florida Institute of Technology (Florida Tech) has developed a Hydrodynamic Tesla, hydrodynamic, laminar, fluid, flow, model, prototype testing, Tesla wheel. I. INTRODUCTION The southeast region

Wood, Stephen L.

240

Determination of beam energy at TESLA using radiative return events  

E-print Network

Determination of beam energy at TESLA using radiative return events ARND HINZE DESY Zeuthen at TESLA. It was suggested to use this method to cross check and calibrate the magnet spectrometer used for measurement of the beam energy at TESLA. A preliminary assessment of the statistical and systematic errors

241

TESLA POLARIMETERS V.GHARIBYAN, N. MEYNERS, K. P. SCH  

E-print Network

TESLA POLARIMETERS V.GHARIBYAN, N. MEYNERS, K. P. SCH  ULER DESY, Deutsches Elektronen Synchrotron + e linear collider machine TESLA. A segment of the beam delivery system has been identi#12;ed, which the pulse and bunch structure of TESLA. This will permit very fast and ac- curate measurements

242

Luminosity Stability Issues for the TESLA Beam Delivery System (BDS)  

E-print Network

Luminosity Stability Issues for the TESLA Beam Delivery System (BDS) Nicholas Walker1 (DESY, Germany) Andrzej Wolski2 (Daresbury Laboratory, UK) TESLA 2000-22 October 17, 2000 1 Introduction Given of ground motion and vibration in linear colliders both for TESLA and NLC/JLC (see for example [1

243

Analyse de l'architecture GPU Tesla Sylvain Collange  

E-print Network

Analyse de l'architecture GPU Tesla Sylvain Collange DALI, ELIAUS, Universit´e de Perpignan sylvain comprise. Nous pr´esentons ici une description du fonctionnement de l'architecture Tesla de NVIDIA et de;2 Tesla Nous nous pencherons dans cet article sur l'architecture des GPU NVIDIA d´ebut´ee avec le G80 (Ge

Boyer, Edmond

244

Multicore Platforms for Scientific Computing: Cell BE and NVIDIA Tesla  

E-print Network

Multicore Platforms for Scientific Computing: Cell BE and NVIDIA Tesla J. Fern´andez, M.E. Acacio Tesla computing solutions. The former is a re- cent heterogeneous chip-multiprocessor (CMP) architecture, multicore, Cell BE, NVIDIA Tesla, CUDA 1 Introduction Nowadays, multicore architectures are omnipresent

Acacio, Manuel

245

TESLA Technical Design Report Editors: R.Klanner  

E-print Network

TESLA Technical Design Report PART VI Appendices March 2001 Editors: R.Klanner Chapter 1: V.Rith #12;#12;Introduction VI-i Introduction These appendices to the TESLA Technical Design Report (TDR) describe four addi- tional particle-physics projects, which can be carried out at the TESLA e+ e- -collider

246

TESLA 2002-10 CBP Tech Note-268  

E-print Network

LCC-0108 TESLA 2002-10 CBP Tech Note-268 Comparison of Emittance Tuning Simulations in the NLC and TESLA Damping Rings A. Wolski LBNL W. Decking DESY November 11th , 2002 Abstract Vertical emittance is a critical issue for future linear collider damping rings. Both NLC and TESLA specify vertical emittance

247

TESLA Report 2005-08 Hamburg 28.02.2005  

E-print Network

TESLA Report 2005-08 Hamburg 28.02.2005 First Generation of Optical Fiber Phase Reference Distribution System for TESLA Krzysztof Czubaa , Frank Eintsb , Matthias Felberb , Janusz Dobrowolskia , Stefan describes the design of a phase stable Fiber Optic (FO) link for the TESLA technology based projects

248

TESLA Report 2006-04 DESY Thesis 2006-000  

E-print Network

TESLA Report 2006-04 DESY Thesis 2006-000 WARSAW UNIVERSITY OF TECHNOLOGY Faculty of Electronics and Informational Technologies Institute of Electronic Systems ELHEP Laboratory DESY TESLA LLRF Team Jerzy Stefan Zieliski Synchronic, optical transmission data link integrated with FPGA circuits (for TESLA LLRF control

249

TESLA: A Formally Defined Event Specification Language Gianpaolo Cugola  

E-print Network

TESLA: A Formally Defined Event Specification Language Gianpaolo Cugola Dip. di Elettronica e to clearly state how the system should behave. Moving from these premises, we present TESLA, a complex event specification language. Each TESLA rule considers incoming data items as notifi- cations of events and defines

Cugola, Gianpaolo

250

Coronary Artery Flow Measurement Using Navigator Echo Gated Phase Contrast Magnetic Resonance Velocity Mapping at 3.0 Tesla  

PubMed Central

A validation study and early results for noninvasive, in vivo measurement of coronary artery blood flow using phase contrast magnetic resonance imaging (PC-MRI) at 3.0 Tesla is presented. Accuracy of coronary artery blood flow measurements by phase contrast MRI is limited by heart and respiratory motion as well as the small size of the coronary arteries. In this study, a navigator-echo gated, cine phase velocity mapping technique is described to obtain time-resolved velocity and flow waveforms of small diameter vessels at 3.0 Tesla. Phantom experiments using steady, laminar flow are presented to validate the technique and show flow rates measured by 3.0 Tesla phase contrast MRI to be accurate within 15% of true flow rates. Subsequently, in vivo scans on healthy volunteers yield velocity measurements for blood flow in the right, left anterior descending, and left circumflex arteries. Measurements of average, cross-sectional velocity were obtainable in 224/243 (92%) of the cardiac phases. Time-averaged, cross-sectional velocity of the blood flow was 6.84.3 cm/s in the LAD, 8.03.8 cm/s in the LCX, and 6.01.6 cm/s in the RCA. PMID:18036532

Johnson, Kevin; Sharma, Puneet; Oshinski, John

2009-01-01

251

George Gollin, Investigation of TESLA Damping Ring Kickers using the A0 Photoinjector Beam 1 Investigation of TESLA Damping  

E-print Network

George Gollin, Investigation of TESLA Damping Ring Kickers using the A0 Photoinjector Beam 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . .. .. . . . .. . . . .. . . . . . . .. .. . . . . . . IPhysicsP Illinois Investigation of TESLA Damping Ring Kickers using the A0 Photoinjector Beam George, Investigation of TESLA Damping Ring Kickers using the A0 Photoinjector Beam 2

Gollin, George

252

Novel Contrast Mechanisms at 3 Tesla and 7 Tesla  

PubMed Central

Osteoarthritis (OA) is the most common musculoskeletal degenerative disease, affecting millions of people. Although OA has been considered primarily a cartilage disorder associated with focal cartilage degeneration, it is accompanied by well-known changes in subchondral and trabecular bone, including sclerosis and osteophyte formation. The exact cause of OA initiation and progression remains under debate, but OA typically first affects weightbearing joints such as the knee. Magnetic resonance imaging (MRI) has been recognized as a potential tool for quantitative assessment of cartilage abnormalities due to its excellent soft tissue contrast. Over the last two decades, several new MR biochemical imaging methods have been developed to characterize the disease process and possibly predict the progression of knee OA. These new MR biochemical methods play an important role not only for diagnosis of disease at an early stage, but also for their potential use in monitoring outcome of various drug therapies (success or failure). Recent advances in multicoil radiofrequency technology and high field systems (3 T and above) significantly improve the sensitivity and specificity of imaging studies for the diagnosis of musculoskeletal disorders. The current state-of-the-art MR imaging methods are briefly reviewed for the quantitative biochemical and functional imaging assessment of musculoskeletal systems. PMID:18850506

Regatte, Ravinder R.; Schweitzer, Mark E.

2013-01-01

253

Serotonergic modulation of neuronal responses to behavioural inhibition and reinforcing stimuli: an fMRI study in healthy volunteers.  

PubMed

Serotonin (5-HT) has been implicated in the aetiology of a number of psychiatric conditions, including depression, anxiety and antisocial personality disorder. The development of these disorders may arise from alterations in underlying motivational and cognitive processes such as emotional recognition, reinforcement processing and central inhibitory control. This study aimed to localize where in the brain 5-HT modulates neuropsychological processes relevant to putative 5-HT disorders, using functional magnetic resonance imaging. We examined the effect of the antidepressant mirtazapine on brain activations associated with behavioural inhibition and reinforcement processing in healthy subjects. Forty-five men were randomly allocated to receiving mirtazapine or placebo in a double-blind fashion. A Go/No-Go, Reward/No-Reward and Loss/No-loss task were performed during functional magnetic resonance imaging using a 1.5 Tesla Philips Gyroscan scanner. Blood oxygenation level dependent (BOLD) responses were analysed using SPM2. Task activations were largely consistent with previous findings. Mirtazapine modulated brain activations in the Go/No-Go and Reward/No-Reward task. During behavioural inhibition, enhanced activations were observed in the right orbitofrontal cortex (BA47). Increased activations in bilateral parietal cortex were found during the Reward task while no significant interaction was observed in the Loss task. Our results support the suggestion of an important role of serotonin in modulating basic processes involved in psychiatric disorders. Combining drug challenge with fMRI (pharmacoMRI; pMRI) is a promising tool for investigating these processes in healthy as well as patient groups. PMID:16420462

Vllm, Birgit; Richardson, Paul; McKie, Shane; Elliott, Rebecca; Deakin, J F W; Anderson, Ian M

2006-01-01

254

Strengthening safety in the MRI room.  

PubMed

A new MRI and CT scanning unit at Winchester's Royal Hampshire County Hospital, run by the Hampshire Hospitals NHS Foundation Trust, has been officially opened by the city's MP, Steven Brine, having been completed in February by Brymor Contractors, under advice from TKL Architects, to replace a former imaging facility badly damaged by a fire in December 2011. As HEJ editor, Jonathan Baillie, reports, the new building features a head and whole body HD imaging CT scanner from GE, and a 1.5 T Philips Ingenia MRI scanner, as well as Ferroguard ferromagnetic detection equipment from Metrasens designed to 'screen' individuals about to enter the MRI scanning room for ferrous objects. PMID:24138000

Baillie, Jonathan

2013-09-01

255

A study of quantification of aortic compliance in mice using radial acquisition phase contrast MRI  

NASA Astrophysics Data System (ADS)

Spatiotemporal changes in blood flow velocity measured using Phase contrast Magnetic Resonance Imaging (MRI) can be used to quantify Pulse Wave Velocity (PWV) and Wall Shear Stress (WSS), well known indices of vessel compliance. A study was conducted to measure the PWV in the aortic arch in young healthy children using conventional phase contrast MRI and a post processing algorithm that automatically track the peak velocity in phase contrast images. It is shown that the PWV calculated using peak velocity-time data has less variability compared to that using mean velocity and flow. Conventional MR data acquisition techniques lack both the spatial and temporal resolution needed to accurately calculate PWV and WSS in in vivo studies using transgenic animal models of arterial diseases. Radial k-space acquisition can improve both spatial and temporal resolution. A major part of this thesis was devoted to developing technology for Radial Phase Contrast Magnetic Resonance (RPCMR) cine imaging on a 7 Tesla Animal scanner. A pulse sequence with asymmetric radial k-space acquisition was designed and implemented. Software developed to reconstruct the RPCMR images include gridding, density compensation and centering of k-Space that corrects the image ghosting introduced by hardware response time. Image processing software was developed to automatically segment the vessel lumen and correct for phase offset due to eddy currents. Finally, in vivo and ex vivo aortic compliance measurements were conducted in a well-established mouse model for atherosclerosis: Apolipoprotein E-knockout (ApoE-KO). Using RPCMR technique, a significantly higher PWV value as well as a higher average WSS was detected among 9 months old ApoE-KO mice compare to in wild type mice. A follow up ex-vivo test of tissue elasticity confirmed the impaired distensibility of aortic arteries among ApoE-KO mice.

Zhao, Xuandong

256

Vacuum Attachment for XRF Scanner  

NASA Technical Reports Server (NTRS)

Vacuum apparatuses have been developed for increasing the range of elements that can be identified by use of x-ray fluorescent (XRF) scanners of the type mentioned in the two immediately preceding articles. As a consequence of the underlying physical principles, in the presence of air, such an XRF scanner is limited to analysis of chlorine and elements of greater atomic number. When the XRF scanner is operated in a vacuum, it extends the range of analysis to lower atomic numbers - even as far as aluminum and sodium. Hence, more elements will be available for use in XRF labeling of objects as discussed in the two preceding articles. The added benefits of the extended capabilities also have other uses for NASA. Detection of elements of low atomic number is of high interest to the aerospace community. High-strength aluminum alloys will be easily analyzed for composition. Silicon, a major contaminant in certain processes, will be detectable before the process is begun, possibly eliminating weld or adhesion problems. Exotic alloys will be evaluated for composition prior to being placed in service where lives depend on them. And in the less glamorous applications, such as bolts and fasteners, substandard products and counterfeit items will be evaluated at the receiving function and never allowed to enter the operation

Schramm, Harry F.; Kaiser, Bruce

2005-01-01

257

Neurodegenerative changes in Alzheimer's disease: a comparative study of manual, semi-automated, and fully automated assessment using MRI  

NASA Astrophysics Data System (ADS)

Objective quantification of disease specific neurodegenerative changes can facilitate diagnosis and therapeutic monitoring in several neuropsychiatric disorders. Reproducibility and easy-to-perform assessment are essential to ensure applicability in clinical environments. Aim of this comparative study is the evaluation of a fully automated approach that assesses atrophic changes in Alzheimer's disease (AD) and Mild Cognitive Impairment (MCI). 21 healthy volunteers (mean age 66.2), 21 patients with MCI (66.6), and 10 patients with AD (65.1) were enrolled. Subjects underwent extensive neuropsychological testing and MRI was conducted on a 1.5 Tesla clinical scanner. Atrophic changes were measured automatically by a series of image processing steps including state of the art brain mapping techniques. Results were compared with two reference approaches: a manual segmentation of the hippocampal formation and a semi-automated estimation of temporal horn volume, which is based upon interactive selection of two to six landmarks in the ventricular system. All approaches separated controls and AD patients significantly (10 -5 < p < 10 -4) and showed a slight but not significant increase of neurodegeneration for subjects with MCI compared to volunteers. The automated approach correlated significantly with the manual (r = -0.65, p < 10 -6) and semi automated (r = -0.83, p < 10 -13) measurements. It proved high accuracy and at the same time maximized observer independency, time reduction and thus usefulness for clinical routine.

Fritzsche, Klaus H.; Giesel, Frederik L.; Heimann, Tobias; Thomann, Philipp A.; Hahn, Horst K.; Pantel, Johannes; Schrder, Johannes; Essig, Marco; Meinzer, Hans-Peter

2008-03-01

258

MRI Compatibility of Robot Actuation Techniques - A Comparative Study  

PubMed Central

This paper reports an experimental evaluation of the following three different MRI-compatible actuators: a Shinsei ultrasonic motor, a Nanomotion ultrasonic motor and a pneumatic cylinder actuator. We report the results of a study comparing the effect of these actuators on the signal to noise ratio (SNR) of MRI images under a variety of experimental conditions. Evaluation was performed with the controller inside and outside the scanner room and with both 1.5T and 3T MRI scanners. Pneumatic cylinders function with no loss of SNR with controller both inside and outside of the scanner room. The Nanomotion motor performs with moderate loss of SNR when moving during imaging. The Shinsei is unsuitable for motion during imaging. All may be used when motion is appropriately interleaved with imaging cycles. PMID:18982643

Fischer, Gregory S.; Krieger, Axel; Iordachita, Iulian; Csoma, Csaba; Whitcomb, Louis L.; Fichtinger, Gabor

2010-01-01

259

Electron Scattering with Polarized Targets at TESLA  

E-print Network

Measurements of polarized electron-nucleon scattering can be realized at the TESLA linear collider facility with projected luminosities that are about two orders of magnitude higher than those expected of other experiments at comparable energies. Longitudinally polarized electrons, accelerated as a small fraction of the total current in the e+ arm of TESLA, can be directed onto a solid state target that may be either longitudinally or transversely polarized. A large variety of polarized parton distribution and fragmentation functions can be determined with unprecedented accuracy, many of them for the first time. A main goal of the experiment is the precise measurement of the x- and Q^2-dependence of the experimentally totally unknown quark transversity distributions that will complete the information on the nucleon's quark spin structure as relevant for high energy processes. Comparing their Q^2-evolution to that of the corresponding helicity distributions constitutes an important precision test of the predictive power of QCD in the spin sector. Measuring transversity distributions and tensor charges allows access to the hitherto unmeasured chirally odd operators in QCD which are of great importance to understand the role of chiral symmetry. The possibilities of using unpolarized targets and of experiments with a real photon beam turn TESLA-N into a versatile next-generation facility at the intersection of particle and nuclear physics.

The TESLA-N Study Group; :; M. Anselmino; E. C. Aschenauer; S. Belostotski; W. Bialowons; J. Bluemlein; V. Braun; R. Brinkmann; M. Dueren; F. Ellinghaus; K. Goeke; St. Goertz; A. Gute; J. Harmsen; D. v. Harrach; R. Jakob; E. M. Kabuss; R. Kaiser; V. Korotkov; P. Kroll; E. Leader; B. Lehmann-Dronke; L. Mankiewicz; A. Meier; W. Meyer; N. Meyners; D. Mueller; P. J. Mulders; W. -D. Nowak; L. Niedermeier; K. Oganessyan; P. V. Pobilitsa; M. V. Polyakov; G. Reicherz; K. Rith; D. Ryckbosch; A. Schaefer; K. Sinram; G. v. d. Steenhoven; E. Steffens; J. Steijger; C. Weiss

2000-11-24

260

Bohr quantum theory and (Tesla) magnetic monopoles  

E-print Network

In this work we apply Bohr (Old quantum atomic) theory for analysis of the magnetic monopoles problem. We reproduce exactly some basic elements of the Dirac magnetic monopoles theory, especially Dirac electric/magnetic charge quantization condition. Also, we suggest a new, effective, simply called Tesla model (for analogy with positions of the solenoids by Tesla inductive motor) of the magnetic monopole instead of usual effective Dirac model (half-infinite, very tinny solenoid) of the magnetic monopole. In our, i.e. Tesla model we use three equivalent very tiny solenoids connected in series with a voltage source. One end of any solenoid is placed at the circumference of a circle and solenoids are directed radially toward circle center. Length of any solenoid is a bit smaller than finite circle radius so that other end of any solenoid is very close to the circle center. Angles between neighbouring solenoids equal $120^{\\circ}$. All this implies that, practically, there is no magnetic field, or, magnetic pole, e.g. $S$, in the circle center, and that whole system holds only other, $N$ magnetic pole, at the ends of the solenoids at circle circumference.

Vladan Pankovic; Darko V. Kapor; Stevica Djurovic; Miodrag Krmar

2010-07-02

261

Characterization of acoustic noise in a neonatal intensive care unit MRI system  

PubMed Central

Background To eliminate the medical risks and logistical challenges of transporting infants from the neonatal intensive care unit (NICU) to the radiology department for magnetic resonance imaging, a small-footprint 1.5-T MRI scanner has been developed for neonatal imaging within the NICU. MRI is known to be noisy, and exposure to excessive acoustic noise has the potential to elicit physiological distress and impact development in the term and preterm infant. Objective To measure and compare the acoustic noise properties of the NICU MRI system against those of a conventional 1.5-T MRI system. Materials and methods We performed sound pressure level measurements in the NICU MRI scanner and in a conventional adult-size whole-body 1.5-T MRI system. Sound pressure level measurements were made for six standard clinical MR imaging protocols. Results The average sound pressure level value, reported in unweighted (dB) and A-weighted (dBA) decibels for all six imaging pulse sequences, was 73.8 dB and 88 dBA for the NICU scanner, and 87 dB and 98.4 dBA for the conventional MRI scanner. The sound pressure level values measured on the NICU scanner for each of the six MR imaging pulse sequences were consistently and significantly (P=0.03) lower, with an average difference of 14.2 dB (range 1021 dB) and 11 dBA (range 518 dBA). The sound pressure level frequency response of the two MR systems showed a similar harmonic structure above 200 Hz for all imaging sequences. The amplitude, however, was appreciably lower for the NICU scanner, by as much as 30 dB, for frequencies below 200 Hz. Conclusion The NICU MRI system is quieter than conventional MRI scanners, improving safety for the neonate and facilitating siting of the unit within the NICU. PMID:24595878

Li, Yu; Pratt, Ronald G.; Baroch, Kelly A.; Loew, Wolfgang; Daniels, Barret R.; Giaquinto, Randy O.; Merhar, Stephanie L.; Kline-Fath, Beth M.; Dumoulin, Charles L.

2014-01-01

262

L-band superconducting cavities at KEK for TESLA  

Microsoft Academic Search

An attractive future application of superconducting cavities is a TeV energy superconducting linear collider (TESLA). The substantial merits of TESLA compared to a normal conducting linear collider are to loosening of alignment tolerance and less wake field due to the lower frequency (1.3 GHz). The final focus also is easier to obtain by having the electron\\/positron population in bunches. TESLA

K. Saito; S. Noguchi; E. Kako; M. Ono; T. Shishido; T. Tajima; M. Matsuoka; H. Miwa; T. Suzuki; H. Uniezawa

1993-01-01

263

77 FR 60672 - Grant of Authority for Subzone Status; Tesla Motors, Inc., (Electric Passenger Vehicles), Palo...  

Federal Register 2010, 2011, 2012, 2013

...Grant of Authority for Subzone Status; Tesla Motors, Inc., (Electric Passenger Vehicles...passenger vehicle manufacturing facilities of Tesla Motors, Inc., located in Palo Alto and...and related powertrain components at the Tesla Motors, Inc., facilities located...

2012-10-04

264

76 FR 60124 - Tesla Motors, Inc.; Grant of Petition for Temporary Exemption From the Electronic Stability...  

Federal Register 2010, 2011, 2012, 2013

...Administration [Docket No. NHTSA-2011-0110] Tesla Motors, Inc.; Grant of Petition for Temporary Exemption...SUMMARY: This notice grants the petition of Tesla Motors, Inc. (Tesla) for the temporary exemption of its Roadster...

2011-09-28

265

77 FR 22383 - Petition for Exemption From the Federal Motor Vehicle Motor Theft Prevention Standard; TESLA  

Federal Register 2010, 2011, 2012, 2013

...Federal Motor Vehicle Motor Theft Prevention Standard; TESLA AGENCY: National Highway Traffic Safety Administration...SUMMARY: This document grants in full the petition of Tesla Motors Inc's. (Tesla) for an exemption of the Model S vehicle line...

2012-04-13

266

High gain proportional rf control stability at TESLA cavities Elmar Vogel  

E-print Network

High gain proportional rf control stability at TESLA cavities Elmar Vogel Deutsches Elektronen) based on TESLA technology. Additional control loops improve the field regulation by treating repetitive loops is desirable for the strong suppression of nonpredictive and nonrepetitive disturbances. TESLA

267

Contributions to the LCWS99, Sitges, April 1999 TESLA Report 1999-20 Contributions to the LCWS99, Sitges, April 1999 TESLA Report 1999-20  

E-print Network

Contributions to the LCWS99, Sitges, April 1999 TESLA Report 1999-20 #12;Contributions to the LCWS99, Sitges, April 1999 TESLA Report 1999-20 #12;Contributions to the LCWS99, Sitges, April 1999 TESLA Report 1999-20 #12;Contributions to the LCWS99, Sitges, April 1999 TESLA Report 1999-20 #12;Contributions

268

Polarized Electron-Nucleon Scattering at The TESLA-N Study-Group  

E-print Network

DESY TESLA-N Polarized Electron-Nucleon Scattering at TESLA The TESLA-N Study-Group http://www.ifh.de/hermes/future | THE BASIC IDEA | A Polarized Fixed-Target Experiment at TESLA Basic Idea: Use one arm of the TESLA collider 0 0 1 1 01 (north arm) Magnet TESLA Main Linac TESLA­N 250 GeV Electrons Separation Building

269

The Transeurope Footrace Project: longitudinal data acquisition in a cluster randomized mobile MRI observational cohort study on 44 endurance runners at a 64-stage 4,486km transcontinental ultramarathon  

PubMed Central

Background The TransEurope FootRace 2009 (TEFR09) was one of the longest transcontinental ultramarathons with an extreme endurance physical load of running nearly 4,500 km in 64 days. The aim of this study was to assess the wide spectrum of adaptive responses in humans regarding the different tissues, organs and functional systems being exposed to such chronic physical endurance load with limited time for regeneration and resulting negative energy balance. A detailed description of the TEFR project and its implemented measuring methods in relation to the hypotheses are presented. Methods The most important research tool was a 1.5 Tesla magnetic resonance imaging (MRI) scanner mounted on a mobile unit following the ultra runners from stage to stage each day. Forty-four study volunteers (67% of the participants) were cluster randomized into two groups for MRI measurements (22 subjects each) according to the project protocol with its different research modules: musculoskeletal system, brain and pain perception, cardiovascular system, body composition, and oxidative stress and inflammation. Complementary to the diverse daily mobile MR-measurements on different topics (muscle and joint MRI, T2*-mapping of cartilage, MR-spectroscopy of muscles, functional MRI of the brain, cardiac and vascular cine MRI, whole body MRI) other methods were also used: ice-water pain test, psychometric questionnaires, bioelectrical impedance analysis (BIA), skinfold thickness and limb circumference measurements, daily urine samples, periodic blood samples and electrocardiograms (ECG). Results Thirty volunteers (68%) reached the finish line at North Cape. The mean total race speed was 8.35 km/hour. Finishers invested 552 hours in total. The completion rate for planned MRI investigations was more than 95%: 741 MR-examinations with 2,637 MRI sequences (more than 200,000 picture data), 5,720 urine samples, 244 blood samples, 205 ECG, 1,018 BIA, 539 anthropological measurements and 150 psychological questionnaires. Conclusions This study demonstrates the feasibility of conducting a trial based centrally on mobile MR-measurements which were performed during ten weeks while crossing an entire continent. This article is the reference for contemporary result reports on the different scientific topics of the TEFR project, which may reveal additional new knowledge on the physiological and pathological processes of the functional systems on the organ, cellular and sub-cellular level at the limits of stress and strain of the human body. Please see related articles: http://www.biomedcentral.com/1741-7015/10/76 and http://www.biomedcentral.com/1741-7015/10/77 PMID:22812450

2012-01-01

270

A novel front-end chip for a human PET scanner based on monolithic detector blocks  

NASA Astrophysics Data System (ADS)

We are developing a positron emission tomography (PET) scanner based on avalanche photodiodes (APD), monolithic LYSO:Ce scintillator crystals and a dedicated readout chip. All these components allow operation inside a magnetic resonance imaging (MRI) scanner with the aim of building a PET/MRI hybrid imaging system for clinical human brain studies. Previous work verified the functional performance of our first chip (VATA240) based on a leading edge comparator and the principle of operation of our radiation sensors, which are capable of providing reconstructed images of positron point sources with spatial resolutions of 2.1 mm FWHM. The new VATA241 chip presented in this work has been designed with the aim of reducing the coincidence window of our final PET scanner by implementing an on-chip constant fraction discriminator (CFD), as well as providing a better robustness for its implementation in the full-scale PET scanner. Results from the characterization of the VATA241 chip are presented, together with the first results on coincidence performance, validating the new design for our application.

Sarasola, I.; Rato Mendes, P.; Cuerdo, R.; Garca de Acilu, P.; Navarrete, J.; Cela, J. M.; Oller, J. C.; Romero, L.; Prez, J. M.

2011-01-01

271

Stanowisko testowe z miedzian? struktur? typu TESLA (Test stand with copper TESLA structure)  

Microsoft Academic Search

The paper presents preparation of a copper TESLA structure for the use in laboratory test stand. Standing wave principle of operation of the structure and basic characteristics are described. Sturucture tuning procedure is discussed and tuning results are presented. Construction of laboratory test stand is shortly dscribed. Sample results obtained from test stand control system are presented and discussed. Structures

J Glowka; M Macias; K Czuba; K Pozniak; R Romaniuk

2009-01-01

272

Competitive advantage of PET/MRI.  

PubMed

Multimodality imaging has made great strides in the imaging evaluation of patients with a variety of diseases. Positron emission tomography/computed tomography (PET/CT) is now established as the imaging modality of choice in many clinical conditions, particularly in oncology. While the initial development of combined PET/magnetic resonance imaging (PET/MRI) was in the preclinical arena, hybrid PET/MR scanners are now available for clinical use. PET/MRI combines the unique features of MRI including excellent soft tissue contrast, diffusion-weighted imaging, dynamic contrast-enhanced imaging, fMRI and other specialized sequences as well as MR spectroscopy with the quantitative physiologic information that is provided by PET. Most evidence for the potential clinical utility of PET/MRI is based on studies performed with side-by-side comparison or software-fused MRI and PET images. Data on distinctive utility of hybrid PET/MRI are rapidly emerging. There are potential competitive advantages of PET/MRI over PET/CT. In general, PET/MRI may be preferred over PET/CT where the unique features of MRI provide more robust imaging evaluation in certain clinical settings. The exact role and potential utility of simultaneous data acquisition in specific research and clinical settings will need to be defined. It may be that simultaneous PET/MRI will be best suited for clinical situations that are disease-specific, organ-specific, related to diseases of the children or in those patients undergoing repeated imaging for whom cumulative radiation dose must be kept as low as reasonably achievable. PET/MRI also offers interesting opportunities for use of dual modality probes. Upon clear definition of clinical utility, other important and practical issues related to business operational model, clinical workflow and reimbursement will also be resolved. PMID:23791129

Jadvar, Hossein; Colletti, Patrick M

2014-01-01

273

TESLA-FEL 2006-07 Superconducting cavity driving  

E-print Network

TESLA-FEL 2006-07 Superconducting cavity driving with FPGA controller Tomasz Czarski, Waldemar Koprek, Krzysztof T. Poniak, Ryszard S. Romaniuk, Warsaw University of Technology Stefan Simrock (FPGA) based system. Additionally, a single 9-cell TESLA Superconducting cavity of the FNPL Photo

274

A Eight-Tesla Superconducting Magnet for Cyclotron Studies  

Microsoft Academic Search

Superconducting magnets have become broadly used for cyclotrons due to advantages of compactness and lower operation costs compared to conventional magnets. To gain benefits of higher magnetic fields beyond the 5 tesla cyclotron magnets which are under operation in several laboratories including the MSU\\/NSCL, a test magnet which can produce fields higher than 8 tesla was constructed. Our goal was

Jong-Won Kim

1994-01-01

275

TESLA Report 2005-02 DSP Integrated, Parameterized, FPGA Based  

E-print Network

TESLA Report 2005-02 DSP Integrated, Parameterized, FPGA Based Cavity Simulator & Controller@ntmail.desy.de, rrom@mail.desy.de Institute of Electronic Systems, Warsaw University of Technology, ELHEP Group and TESLA in DESY, Hamburg (now predicted for the VUV and X-Ray FEL). The controller bases on a programmable

276

TESLA Report 2003-20 Cavity Digital Control Testing System  

E-print Network

TESLA Report 2003-20 Cavity Digital Control Testing System By Simulink Step Operation Method For TESLA Linear Accelerator And Free Electron Laser Tomasz Czarski, Ryszard Romaniuk, Krzysztof Poniak ELHEP Laboratory, Institute of Electronic Systems (ISE), Warsaw University of Technology Stefan Simrock

277

The Design and Dimensional Analysis of a Tesla Turbine  

E-print Network

THE DESIGN AND DIMENSIONAL ANALYSIS OF A TESLA TURBINE A Thesis By BOBBY DEAN RICHARDBON Submitted to the Graduate School of the Agricultural and mechanical College of Texas in psrtial fulfillment of the requirements for the degree of ASTER... . ~ ~ . ~ ~ . ~ ~ ~ ~ 24 DLSCUSSIQN OF RESULTS . ~ . . ~ . , ~. . . . . . ~ . . ~ . . ~. . . 28 CONCLUSIONS AND RECOMMENDATIONS . ~. . . . . . . ~. . . 33 BIBLIOGRAPHY ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 3 S LIST OF FIGURES Figure The Tesla...

Richardson, Bobby Dean

2012-06-07

278

Multichannel Compressive Sensing MRI Using Noiselet Encoding  

E-print Network

The incoherence between measurement and sparsifying transform matrices and the restricted isometry property (RIP) of measurement matrix are two of the key factors in determining the performance of compressive sensing (CS). In CS-MRI, the randomly under-sampled Fourier matrix is used as the measurement matrix and the wavelet transform is usually used as sparsifying transform matrix. However, the incoherence between the randomly under-sampled Fourier matrix and the wavelet matrix is not optimal, which can deteriorate the performance of CS-MRI. Using the mathematical result that noiselets are maximally incoherent with wavelets, this paper introduces the noiselet unitary bases as the measurement matrix to improve the incoherence and RIP in CS-MRI, and presents a method to design the pulse sequence for the noiselet encoding. This novel encoding scheme is combined with the multichannel compressive sensing (MCS) framework to take the advantage of multichannel data acquisition used in MRI scanners. An empirical RIP a...

Pawar, Kamlesh; Zhang, Jingxin

2014-01-01

279

Academic and Career Advising of Scanners  

ERIC Educational Resources Information Center

"Scanners" has become a common term for a recently identified category of people who find choosing just one interest or career path difficult (Sher, 2006). Academic and career advisors who work with scanners will likely find that these students have difficulty selecting an academic major or career path and that they seem to suffer anxiety and a

Bloom, Arvid J.; Tripp, Philip R.; Shaffer, Leigh S.

2011-01-01

280

Nikola Tesla: the man behind the magnetic field unit.  

PubMed

The magnetic field strength of both the magnet and gradient coils used in MR imaging equipment is measured in Tesla units, which are named for Nikola Tesla. This article presents the life and achievements of this Serbian-American inventor and researcher who discovered the rotating magnetic field, the basis of most alternating-current machinery. Nikola Tesla had 700 patents in the United States and Europe that covered every aspect of science and technology. Tesla's discoveries include the Tesla coil, AC electrical conduction, improved lighting, newer forms of turbine engines, robotics, fluorescent light, wireless transmission of electrical energy, radio, remote control, discovery of cosmic radio waves, and the use of the ionosphere for scientific purposes. He was a genius whose discoveries had a pivotal role in advancing us into the modern era. PMID:14994307

Roguin, Ariel

2004-03-01

281

Abstract--Magnetic Resonance Imaging (MRI) guided nanorobotic systems that could perform diagnostic, curative  

E-print Network

groups have employed magnetized micro/ nanoparticles and have implemented magnetic propulsion techniquesAbstract-- Magnetic Resonance Imaging (MRI) guided nanorobotic systems that could perform on the use of a MRI scanner to induce the required external driving forces to guide magnetic nanocapsules

Mavroidis, Constantinos

282

Simplified MRI  

NSDL National Science Digital Library

Is it a tumor? Magnetic Resonance Imaging (MRI) can tell. Your head is full of tiny radio transmitters (the nuclear spins of the hydrogen nuclei of your water molecules). In an MRI unit, these little radios can be made to broadcast their positions, giving a detailed picture of the inside of your head.

Simulations, Phet I.; Dubson, Michael; Lemaster, Ron; Mckagan, Sam; Perkins, Kathy; Wieman, Carl

2006-07-01

283

Evaluating Commercial Scanners for Astronomical Image Digitization  

NASA Astrophysics Data System (ADS)

Many organizations have been interested in understanding if commercially available scanners are adequate for scientifically useful digitization. These scanners range in price from a few hundred to a few tens of thousands of dollars (USD), often with little apparent difference in performance specifications. This paper describes why the underlying technology used in flatbed scanners tends to effectively limit resolutions to the 600-1200 dots per inch (dpi) range and how the overall system Modulation Transfer Function (MTF) can be used to evaluate the quality of the digitized data for the small feature sizes found in astronomical images. Two scanners, the Epson V750 flatbed scanner and the Nikon Cool Scan 9000ED film strip scanner, are evaluated through their Modulation Transfer Functions (MTF). The MTF of the Harvard DASCH scanner is also shown for comparison. The particular goal of this evaluation was to understand if the scanners could be used for digitizing spectral plates at the University of Toronto. The plates of primary interest were about 15 mm (5/8 inch) wide by 180 mm (7~inches) long and 50 mm x 80 mm (2 x 3 inches). The results of the MTF work show that the Epson scanner, despite claims of high resolution, is of limited value for scientific imaging of feature sizes below about 50 ?m and therefore not a good candidate for digitizing the spectral plates and problematic for scanning direct plates. The Nikon scanner is better and, except for some frustrating limitations in its software, its performance seems to hold promise as a digitizer for spectral plates in the University of Toronto collection.

Simcoe, R. J.

2009-08-01

284

Pushing spatial and temporal resolution for functional and diffusion MRI in the Human Connectome Project  

PubMed Central

The human connectome project (HCP) relies primarily on three complementary magnetic resonance (MR) methods. These are: 1) resting state functional MR imaging (rfMRI) which uses correlations in the temporal fluctuations in an fMRI time series to deduce functional connectivity; 2) diffusion imaging (dMRI), which provides the input for tractography algorithms used for the reconstruction of the complex axonal fiber architecture; and 3) task based fMRI (tfMRI), which is employed to identify functional parcellation in the human brain in order to assist analyses of data obtained with the first two methods. We describe technical improvements and optimization of these methods as well as instrumental choices that impact speed of acquisition of fMRI and dMRI images at 3 Tesla, leading to whole brain coverage with 2 mm isotropic resolution in 0.7 second for fMRI, and 1.25 mm isotropic resolution dMRI data for tractography analysis with three-fold reduction in total data acquisition time. Ongoing technical developments and optimization for acquisition of similar data at 7 Tesla magnetic field are also presented, targeting higher resolution, specificity of functional imaging signals, mitigation of the inhomogeneous radio frequency (RF) fields and power deposition. Results demonstrate that overall, these approaches represent a significant advance in MR imaging of the human brain to investigate brain function and structure. PMID:23702417

U?urbil, Kamil; Xu, Junqian; Auerbach, Edward J.; Moeller, Steen; Vu, An; Duarte-Carvajalino, Julio M.; Lenglet, Christophe; Wu, Xiaoping; Schmitter, Sebastian; Van de Moortele, Pierre Francois; Strupp, John; Sapiro, Guillermo; De Martino, Federico; Wang, Dingxin; Harel, Noam; Garwood, Michael; Chen, Liyong; Feinberg, David A.; Smith, Stephen M.; Miller, Karla L.; Sotiropoulos, Stamatios N; Jbabdi, Saad; Andersson, Jesper L; Behrens, Timothy EJ; Glasser, Matthew F.; Van Essen, David; Yacoub, Essa

2013-01-01

285

MRI simulator: a teaching tool for radiology  

NASA Astrophysics Data System (ADS)

The increasing use of magnetic resonance imaging (MRI) as a clinical modality has put an enormous burden on medical institutions to cost-effectively teach Mill scanning techniques to technologists and physicians. Since MRI scanner time is a scarce resource, it would be ideal if the teaching could be effectively performed off-line. In order to meet this goal, the Radiology Department has designed and developed a Magnetic Resonance Imaging Simulator. The Simulator in its current implementation mimics the General Electric Signa scanner's user-interface for image acquisition. The design is general enough to be applied to other MRI scanners. One unique feature of the simulator is its incorporation of an image-synthesis module which permits the user to derive images for any arbitrary combination of pulsing parameters for spin-echo, gradient-echo, and inversion recovery pulse sequences. These images are computed in five seconds. The development platform chosen is a standard Apple Macintosh-Il computer with no specialized hardware peripherals. The user-interface is implemented in HyperCard. All other software development including synthesis and display functions are implemented under the MPW 'C' environment. The scan parameters, demographics and images are tracked using an Oracle database. Images are currently stored on magnetic disk but could be stored on optical media with minimal effort.

Rundle, Debra A.; Kishore, Sheel; Seshadri, Sridhar B.; Wehrli, Felix W.

1990-08-01

286

Improved Reliability in Skeletal Age Assessment using a Pediatric Hand MR Scanner with a 0.3T Permanent Magnet.  

PubMed

The purpose of this study was to improve the reliability and validity of skeletal age assessment using an open and compact pediatric hand magnetic resonance (MR) imaging scanner. We used such a scanner with 0.3-tesla permanent magnet to image the left hands of 88 healthy children (aged 3.4 to 15.7 years, mean 8.8 years), and 3 raters (2 orthopedic specialists and a radiologist) assessed skeletal age using those images. We measured the strength of agreement in ratings by values of weighted Cohen's ? and the proportion of cases excluded from rating because of motion artifact and inappropriate positioning. We compared the current results with those of a previous study in which 93 healthy children (aged 4.1 to 16.4 years, mean 9.7 years) were examined with an adult hand scanner. The ? values between raters exceeded 0.80, which indicates almost perfect agreement, and most were higher than those of the previous study. The proportion of cases excluded from rating because of motion artifact or inappropriate positioning was also reduced. The results indicate that use of the compact pediatric hand scanner improved the reliability and validity of skeletal age assessments. PMID:24990466

Terada, Yasuhiko; Kono, Saki; Uchiumi, Tomomi; Kose, Katsumi; Miyagi, Ryo; Yamabe, Eiko; Fujinaga, Yasunari; Yoshioka, Hiroshi

2014-09-29

287

PERFORMANCE STATUS OF THE RF-GUN BASED INJECTOR OF THE TESLA TEST FACILITY LINAC  

E-print Network

PERFORMANCE STATUS OF THE RF-GUN BASED INJECTOR OF THE TESLA TEST FACILITY LINAC S. Schreiber£ for the TESLA Collaboration, DESY, 22603 Hamburg, Germany Abstract The TESLA Test Facility Linac (TTFL) at DESY uses two modules with 8 TESLA superconducting accelerat- ing structures each to accelerate an electron

288

TESLA Report 2003-19 THE SHORT-RANGE TRANSVERSE WAKE  

E-print Network

TESLA Report 2003-19 THE SHORT-RANGE TRANSVERSE WAKE FUNCTION FOR TESLA ACCELERATING STRUCTURE T of a Free Electron Laser in TESLA project requires very short bunches. It results in a very long interaction calculate the short-range transverse wakefields of the TESLA linac accelerating structure. Wake fields

289

Achievement of 35 MV/m in the Superconducting Nine-Cell Cavities for TESLA 1  

E-print Network

Achievement of 35 MV/m in the Superconducting Nine-Cell Cavities for TESLA 1 L. Lilje2 , D. Kostin Electronvolt Superconducting Linear Accelerator TESLA is the only linear electron-positron collider project reliably achieved in the cavities of the TESLA Test Facility (TTF) accelerator. The upgrade of TESLA to 800

290

DESY, February 2001, TESLA Report 2001-04 Concept of the High Power e  

E-print Network

DESY, February 2001, TESLA Report 2001-04 Concept of the High Power e± Beam Dumps for TESLA W. Bialowons, M. Maslov, M. Schmitz, V. Sytchev #12;1 Concept of the High Power e± Beam Dumps for TESLA W............................................................................................................... 19 #12;2 1 Introduction The TESLA accelerator is equipped with quite a number of extraction lines

291

TESLA Report 2003-29 Functional analysis of DSP blocks in FPGA chips  

E-print Network

TESLA Report 2003-29 Functional analysis of DSP blocks in FPGA chips for application in TESLA LLRF blocks. The new functionalities are well suited for the application in the TESLA LLRF cavity simulation in the FPGA chips of Altera and Xilinx. There were compared the results for a few different chips. The TESLA

292

THE CRYOGENIC SYSTEM OF TESLA S. Wolff, DESY, Notkestr. 85, 22607 Hamburg, Germany  

E-print Network

THE CRYOGENIC SYSTEM OF TESLA S. Wolff, DESY, Notkestr. 85, 22607 Hamburg, Germany for the TESLA collaboration Abstract TESLA, a 33 km long 500 GeV centre-of-mass energy superconducting linear collider The 33 km long e+ e- linear collider TESLA (Tera eV Energy Superconductiong Linear Accelerator) with 500

293

TESLA Report 2005-05 Software Layer for SIMCON ver. 1.1.  

E-print Network

TESLA Report 2005-05 Software Layer for SIMCON ver. 1.1. FPGA-based TESLA Cavity Control System to control FPGA-based LLRF electronic equipment for TESLA. There is presented a universal solution (SIMCON) for TESLA experiment (Test Facility) in DESY. The examples of the build and tested software

294

DAPNIA/SEA-00-15 TESLA Linear Collider : Status Report  

E-print Network

DAPNIA/SEA-00-15 TESLA Linear Collider : Status Report O. Napoly for the TESLA Collaboration CEA) October 24-28, 2000, FNAL, Batavia, IL, USA #12;#12;TESLA Linear Collider : Status Report O. Napoly for the TESLA Collaboration CEA/Saclay, DAPNIA/SEA 91191 Gif-sur-Yvette, FRANCE Abstract. We review the current

295

TESLA Report No. 2000-26 September 2000 Fiber Optic Radiation Sensing Systems  

E-print Network

TESLA Report No. 2000-26 September 2000 Fiber Optic Radiation Sensing Systems for TESLA by H, Germany F. Wulf Hahn-Meitner-Institut HMI, Germany #12;Fiber Optic Radiation Sensing Systems for TESLA of refractive index at high radiation doses 4 3. Fiber optic dosimeter types for different TESLA sections 4 3

296

76 FR 47639 - Tesla Motors, Inc.; Receipt of Petition for Temporary Exemption From the Electronic Stability...  

Federal Register 2010, 2011, 2012, 2013

...Administration [Docket No. NHTSA-2011-0110] Tesla Motors, Inc.; Receipt of Petition for...with the procedures in 49 CFR part 555, Tesla Motors, Inc., has petitioned the agency...and the procedures in 49 CFR part 555, Tesla Motors, Inc. (Tesla) submitted a...

2011-08-05

297

Design of an MRI-compatible robotic stereotactic device for minimally invasive interventions in the breast.  

PubMed

The objective of this work was to develop a robotic device to perform biopsy and therapeutic interventions in the breast with real-time magnetic resonance imaging (MRI) guidance. The device was designed to allow for (i) stabilization of the breast by compression, (ii) definition of the interventional probe trajectory by setting the height and pitch of a probe insertion apparatus, and (iii) positioning of an interventional probe by setting the depth of insertion. The apparatus is fitted with five computer-controlled degrees of freedom for delivering an interventional procedure. The entire device is constructed of MR compatible materials, i.e. nonmagnetic and non-conductive, to eliminate artifacts and distortion of the MR images. The apparatus is remotely controlled by means of ultrasonic motors and a graphical user interface, providing real-time MR-guided planning and monitoring of the operation. Joint motion measurements found probe placement in less than 50 s and sub-millimeter repeatability of the probe tip for same-direction point-to-point movements. However, backlash in the rotation joint may incur probe tip positional errors of up to 5 mm at a distance of 40 mm from the rotation axis, which may occur for women with large breasts. The imprecision caused by this backlash becomes negligible as the probe tip nears the rotation axis. Real-time MR-guidance will allow the physician to correct this error Compatibility of the device within the MR environment was successfully tested on a 4 Tesla MR human scanner PMID:15543863

Larson, Blake T; Erdman, Arthur G; Tsekos, Nikolaos V; Yacoub, Essa; Tsekos, Panagiotis V; Koutlas, Ioannis G

2004-08-01

298

Theory and Performance of Tesla Turbines  

NASA Astrophysics Data System (ADS)

This document summarizes the development of an integral perturbation solution of the equations governing momentum transport in microchannels between disks of multiple-disk drag turbines such as the Tesla turbine. This analysis allows a parametric study of turbine performance based on several nondimensional parameters. The results of this analysis are then compared to two sets of test data published in previous work and by other projects. The results are further compared to Computational Fluid Dynamics (CFD) simulations. Finally, expected performance and potential applications of these devices are discussed in light of the results developed. Analysis of this type of flow problem is a key element in the optimal design of Tesla drag-type turbines for geothermal, waste heat, energy harvesting, or solar alternative energy applications. In multiple-disk turbines, high speed flow enters tangentially at the outer radius of cylindrical microchannels formed by closely spaced parallel disks, spiraling through the channel to an exhaust at a small radius or at the center of the disk. Previous investigations have generally developed models based on simplifying idealizations of the flow in these circumstances. Here, beginning with the momentum and continuity equations for incompressible and steady flow in cylindrical coordinates, an integral solution scheme is developed that leads to a dimensionless perturbation series solution that retains the full complement of momentum and viscous effects to consistent levels of approximation in the series solution. This more rigorous approach indicates all dimensionless parameters that affect flow and transport, and allows a direct assessment of the relative importance of viscous, pressure, and momentum effects in different directions in the flow. The resulting lowest-order equations are solved explicitly and higher order terms in the series solutions are determined numerically. Enhancement of rotor drag in this type of turbine enhances energy conversion efficiency. A modified version of the integral perturbation analysis is presented that incorporates the effects of enhanced drag due to surface microstructuring. Results of the model analysis for smooth disk walls are shown to agree well with experimental performance data for two prototype Tesla turbines, and predictions of performance models developed in earlier investigations. Specifically, experimental efficiencies corelate well with those predicted by the integral perturbation solution, deviating by an average of 29% and a maximum of 52%. Model predictions indicate that enhancement of disk drag by strategic microstructuring of the disk surfaces can significantly increase turbine efficiency. Exploratory calculations with the model indicate that turbine efficiencies exceeding 75% can be achieved by designing for optimal ranges of the governing dimensionless parameters. The same parametric trends in performance are compared to test data for a micro-scale Tesla turbine with water as a working fluid. Experimental efficiencies again correlate well with those predicted by the integral perturbation solution. Exerimental efficiencies show a mean deviation of 52% with efficiencies predicted by the model, and a max deviation of 65%. A Computational Fluid Dynamics (CFD) model is then compared to both the analytical and experimental turbine efficiencies. The CFD solutions of the flow field are then used to help reconcile areas where the analytical predictions do not match experimental data. CFD predicted efficiencies match the efficiencies predicted by the integral perturbation solution very closely, deviating by an average of only 18%. Based on the results of the CFD simulations and experimental data, conclusions are made about the validity of the integral perturbation solution. The model accurately predicts the flow inside the rotor, but a better treatment of the flow in the inlet to the turbine is necessary. Despite this, the integral perturbation solution is shown to be capable of directing high efficiency turbine design, and design strategies and param

Romanin, Vincent Domenic

299

A 3.5 Tesla Laboratory Electromagnet  

NASA Astrophysics Data System (ADS)

We report the design and construction of a laboratory electromagnet utilizing HTS coils in an iron yoke with a magnetic flux density of 3.5 Tesla in a 50-mm air-gap. With continuing improvement in the performance of HTS "BSCCO" wire, several niche HTS magnet applications have become viable at current wire prices. In this instance, the HTS conductor confers the advantages of high field strength combined with compact size and energy efficiency, in an electromagnet of a format suitable for many materials' characterization techniques, such as vibrating-sample magnetometry, for which the current magnet will be employed. The magnet employs four HTS coils, with a total of 1.6 km of BSCCO wire, which are conduction cooled using a single-stage Gifford-McMahon cryocooler, delivering approximately 25 W of cooling power at the target 35 K operating temperature; HTS current leads are utilized to minimize heat leak to the cryogenic environment.

Pooke, D. M.; Chamritski, V.; Gibson, S.; Fee, M.; King, T.; Staines, M. P.; Flower, N. E.; Buckley, R. G.

2004-06-01

300

21 CFR 892.1220 - Fluorescent scanner.  

Code of Federal Regulations, 2010 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices 892.1220 Fluorescent scanner. (a) Identification. A fluorescent...

2010-04-01

301

21 CFR 892.1220 - Fluorescent scanner.  

Code of Federal Regulations, 2011 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices 892.1220 Fluorescent scanner. (a) Identification. A fluorescent...

2011-04-01

302

21 CFR 892.1220 - Fluorescent scanner.  

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices 892.1220 Fluorescent scanner. (a) Identification. A fluorescent...

2014-04-01

303

21 CFR 892.1220 - Fluorescent scanner.  

Code of Federal Regulations, 2013 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices 892.1220 Fluorescent scanner. (a) Identification. A fluorescent...

2013-04-01

304

21 CFR 892.1220 - Fluorescent scanner.  

Code of Federal Regulations, 2012 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices 892.1220 Fluorescent scanner. (a) Identification. A fluorescent...

2012-04-01

305

Hand-held optical fuel pin scanner  

DOEpatents

An optical scanner for indicia arranged in a focal plane perpendicular to an optical system including a rotatable dove prism. The dove prism transmits a rotating image to a stationary photodiode array.

Kirchner, T.L.; Powers, H.G.

1980-12-07

306

Hand-held optical fuel pin scanner  

DOEpatents

An optical scanner for indicia arranged in a focal plane perpendicular to an optical system including a rotatable dove prism. The dove prism transmits a rotating image to a stationary photodiode array.

Kirchner, Tommy L. (Richland, WA); Powers, Hurshal G. (Richland, WA)

1987-01-01

307

Spectrometer and scanner with optofluidic configuration.  

PubMed

We present a spectrometer and scanner based on optofluidic configurations. The main optical component of the spectrometer is a compound optical element consisting of an optofluidic lens and standard blazed diffraction grating. The spectrum size can be changed by filling the lens cavity with different liquids. The scanner comprises two hollow 45 angle prisms oriented at 90 to each other. By changing the liquid inside the prisms, two-dimensional light beam scanning can be performed. PMID:23338199

Calixto, Sergio; Rosete-Aguilar, Martha; Sanchez-Morales, Maria Eugenia; Calixto-Solano, Margarita

2013-01-20

308

TESLA Report 2003-25 ANALYTICAL TREATMENT OF RESISTIVE WAKE  

E-print Network

, V. Tsakanov Center for the Advancement of Natural Discoveries using Light Emission -CANDLE, 375040-mail: ivanian@asls.candle.am #12;TESLA Report 2003-25 2 1. INTRODUCTION The longitudinal and transverse

309

NVIDIA Tesla: A Unified Graphics and Computing Architecture  

Microsoft Academic Search

To enable flexible, programmable graphics and high-performance computing, NVIDIA has developed the Tesla scalable unified graphics and parallel computing architecture. Its scalable parallel array of processors is massively multithreaded and programmable in C or via graphics APIs.

Erik Lindholm; John Nickolls; Stuart F. Oberman; John Montrym

2008-01-01

310

Alternative IR geometries for TESLA with a small crossing angle  

E-print Network

The formulation of hybrid crossing angle schemes has been a recent development of the TESLA collision geometry debate. Here we report on two such schemes, characterised by either a small vertical or horizontal beam crossing angle.

R. Appleby; D. Angal-Kalinin; P. Bambade; B. Mouton; O. Napoly; J. Payet; the TESLA Collaboration

2004-12-09

311

Web server scanner: scanning on IIS CGI and HTTP  

Microsoft Academic Search

This paper explains about the design and implementation of Web server scanner. The scanner detected the security weaknesses on IIS, CGI and HTTP. A report is produced for audit log purposes to help decrease the security weaknesses. In Internet security, no hacking tool is more celebrated than the scanner. The scanner is a program that automatically detects security weaknesses in

Siti Rahayu Selamat

2003-01-01

312

A Laser Range Scanner Designed for Minimum Calibration Complexity  

Microsoft Academic Search

Laser range scanners are a popular method for acquiring three-dimensional geometry due to their accuracy and robustness. Maximizing scanner accuracy while minimizing engineering costs is a key challenge to future scanner designs. Engineering costs arise from both expensive components and difficult calibration requirements. We propose a two camera range scanner design, specifically chosen to minimize calibration complexity and cost. This

James Davis; Xing Chen

2001-01-01

313

Report on the TESLA Engineering Study\\/Review  

Microsoft Academic Search

In March, 2001, the TESLA Collaboration published its Technical Design Report (TDR, see references and links in Appendix), the first sentence of which stated ''...TESLA (TeV-Energy Superconducting Linear Collider) (will be) a superconducting electron-positron collider of initially 500 GeV total energy, extendable to 800 GeV, and an integrated X-ray laser laboratory.'' The TDR included cost and manpower estimates for a

Cornuelle; John C

2002-01-01

314

Test Results of Tesla-Style Cryomodules at Fermilab  

E-print Network

Commissioning and operation of the first Tesla-style Cryomodule (CM-1) at Fermilab was concluded in recent months. A second Tesla Type III+ module, RFCA002, will be replacing it. CM-1 is the first 8-cavity ILC style cryomodule to be built at Fermilab and also the first accelerating cryomodule of the Advanced Superconducting Test Accelerator (ASTA). We report on the operating results of both of these cryomodules.

Harms, E; Chase, B; Crawford, D; Cullerton, E; Edstrom, D; Hocker, A; Kucera, M; Leibfritz, J; Nezhevenko, O; Nicklaus, D; Pischalnikov, Y; Prieto, P; Reid, J; Schappert, W; Varghese, P

2013-01-01

315

Simultaneous MRI and PET imaging of a rat brain.  

PubMed

Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI will allow the correlation of form with function. Our group is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode. Each MRI-PET detector module consists of an array of LSO detector elements coupled through a long fibre optic light guide to a single Hamamatsu flat panel position-sensitive photomultiplier tube (PSPMT). The use of light guides allows the PSPMTs to be positioned outside the bore of a 3T MRI scanner where the magnetic field is relatively small. To test the device, simultaneous MRI and PET images of the brain of a male Sprague Dawley rat injected with FDG were successfully obtained. The images revealed no noticeable artefacts in either image set. Future work includes the construction of a full ring PET scanner, improved light guides and construction of a specialized MRI coil to permit higher quality MRI imaging. PMID:17148823

Raylman, Raymond R; Majewski, Stan; Lemieux, Susan K; Velan, S Sendhil; Kross, Brian; Popov, Vladimir; Smith, Mark F; Weisenberger, Andrew G; Zorn, Carl; Marano, Gary D

2006-12-21

316

Towards Truly Quiet MRI: animal MRI magnetic field gradients as a test platform for acoustic noise reduction  

NASA Astrophysics Data System (ADS)

Clinical MRI acoustic noise, often substantially exceeding 100 dB, causes patient anxiety and discomfort and interferes with functional MRI (fMRI) and interventional MRI. MRI acoustic noise reduction is a long-standing and difficult technical challenge. The noise is basically caused by large Lorentz forces on gradient windings---surrounding the patient bore---situated in strong magnetic fields (1.5 T, 3 T or higher). Pulsed currents of 300 A or more are switched through the gradient windings in sub-milliseconds. Experimenting with hardware noise reduction on clinical scanners is difficult and expensive because of the large scale and weight of clinical scanner components (gradient windings 1000 kg) that require special handling equipment in large engineering test facilities. Our approach is to produce a Truly Quiet (70 dB) small-scale animal imager. Results serve as a test platform for acoustic noise reduction measures that can be implemented in clinical scanners. We have so far decreased noise in an animal scale imager from 108 dB to 71 dB, a 37 dB reduction. Our noise reduction measures include: a gradient container that can be evacuated; inflatable antivibration mounts to prevent transmission of vibrations from gradient winding to gradient container; vibration damping of wires going from gradient to the outside world via the gradient container; and a copper passive shield to prevent the generation of eddy currents in the metal cryostat inner bore, which in turn can vibrate and produce noise.

Edelstein, William; El-Sharkawy, Abdel-Monem

2013-03-01

317

Proposed applications with implementation techniques of the upcoming renewable energy resource, The Tesla Turbine  

NASA Astrophysics Data System (ADS)

Recent research has shown that tesla turbine can be one of the future efficient sources of renewable energy. Modern techniques used for designing of tesla turbine have given optimum results regarding efficiency and applications. In this paper we have suggested fully coordinated applications of tesla turbine in different fields particularly in power generation at both low level and high level generation. In Energy deficient countries the tesla turbine has wide range of applications and it can play an important role in energy management system. Our proposed applications includes, the use of tesla turbine as renewable energy resource using tesla turbine in distributed generation system use of tesla turbine at home for power generation use of tesla turbine in irrigation channels using tesla turbine in hybrid electric vehicles All applications are explained with the help of flow charts and block diagrams and their implementation techniques are also explained in details. The results of physical experiments and simulations are also included for some applications.

Usman Saeed Khan, M.; Maqsood, M. Irfan; Ali, Ehsan; Jamal, Shah; Javed, M.

2013-06-01

318

Portable MRI  

SciTech Connect

This project proposes to: (1) provide the power of MRI to situations where it presently isn't available; (2) perform the engineering required to move from lab to a functional prototype; and (3) leverage significant existing infrastructure and capability in ultra-low field MRI. The reasons for doing this: (1) MRI is the most powerful tool for imaging soft-tissue (e.g. brain); (2) Billions don't have access due to cost or safety issues; (3) metal will heat/move in high magnetic fields; (4) Millions of cases of traumatic brain injury in US alone; (5) even more of non-traumatic brain injury; (6) (e.g. stroke, infection, chemical exposure); (7) Need for early diagnostic; (8) 'Signature' wound of recent conflicts; (9) 22% of injuries; (10) Implications for post-traumatic stress disorder; and (11) chronic traumatic encephalopathy.

Espy, Michelle A. [Los Alamos National Laboratory

2012-06-29

319

MRI-Safe Robot for Endorectal Prostate Biopsy  

PubMed Central

This paper reports the development of an MRI-Safe robot for direct (interventional) MRI-guided endorectal prostate biopsy. The robot is constructed of nonmagnetic and electrically nonconductive materials, and is electricity free, using pneumatic actuation and optical sensors. Targeting biopsy lesions of MRI abnormality presents substantial clinical potential for the management of prostate cancer. The paper describes MRI-Safe requirements, presents the kinematic architecture, design and construction of the robot, and a comprehensive set of preclinical tests for MRI compatibility and needle targeting accuracy. The robot has a compact and simple 3 degree-of-freedom (DoF) structure, two for orienting a needle-guide and one to preset the depth of needle insertion. The actual insertion is performed manually through the guide and up to the preset depth. To reduce the complexity and size of the robot next to the patient, the depth setting DoF is remote. Experimental results show that the robot is safe to use in any MRI environment (MRI-Safe). Comprehensive MRI tests show that the presence and motion of the robot in the MRI scanner cause virtually no image deterioration or signal to noise ratio (SNR) change. Robots accuracy in bench test, CT-guided in-vitro, MRI-guided in-vitro and animal tests are 0.37mm, 1.10mm, 2.09mm, and 2.58mm respectively. These values are acceptable for clinical use. PMID:25378897

Stoianovici, Dan; Kim, Chunwoo; Srimathveeravalli, Govindarajan; Sebrecht, Peter; Petrisor, Doru; Coleman, Jonathan; Solomon, Stephen B.; Hricak, Hedvig

2014-01-01

320

In vivo MRI and its histological correlates in acute adoptive transfer experimental allergic encephalomyelitis: Quantification of inflammation and oedema  

Microsoft Academic Search

Summary In vivo proton MRI was carried out on a 7 Tesla system at 2-3 day intervals over 10 days in rats with adoptive transfer experimental allergic encephalomyelitis (AT-EAE), an animal model of some aspects of multiple sclerosis. In order to assess the integrity of the blood-brain barrier (BBB), MRI was performed by acquiring quantitative MR-relaxation time Tj images of

Sean P. Morrissey; Horst Stodal; Uwe Zettl; Claudia Simonis; Stefan Jung; Reinhard Kiefer; Hans Lassmann; Hans-Peter Hartung; Axel Haase; Klaus V. Toyka

1996-01-01

321

Women are more strongly affected by dizziness in static magnetic fields of magnetic resonance imaging scanners.  

PubMed

Increasing field strengths in MRI necessitate the examination of potential side effects. Previously reported results have been contradictory, possibly caused by imbalanced samples. We aimed to examine whether special groups of people are more prone to develop side effects that might have led to contradictory results in previous studies. We examined the occurrence of sensory side effects in static magnetic fields of MRI scanners of 1.5, 3, and 7?T and a mock scanner in 41 healthy participants. The contribution of field strength, sex, age, and attention to bodily processes, and stress hormone levels to the sensation of dizziness was examined in separate univariate analyses and in a joint analysis that included all variables. Field strength and sex were significant factors in the joint analysis (P=0.001), with women being more strongly affected than men by dizziness in higher static magnetic fields. This effect was not mediated by the other variables such as attention to bodily symptoms or stress hormones. Further research needs to elucidate the underlying factors of increased dizziness in women in static magnetic fields in MRI. We hypothesize that imbalanced samples of earlier studies might be one reason for previous contradictory results on the side effects of static magnetic fields. PMID:25089803

Heinrich, Angela; Szostek, Anne; Meyer, Patric; Reinhard, Iris; Gilles, Maria; Paslakis, Georgios; Rauschenberg, Jaane; Grbner, Jens; Semmler, Wolfhard; Deuschle, Michael; Meyer-Lindenberg, Andreas; Flor, Herta; Nees, Frauke

2014-10-01

322

Assessment of Safety and Interference Issues of Radio Frequency Identification Devices in 0.3 Tesla Magnetic Resonance Imaging and Computed Tomography  

PubMed Central

The objective of this study was to evaluate two issues regarding magnetic resonance imaging (MRI) including device functionality and image artifacts for the presence of radio frequency identification devices (RFID) in association with 0.3?Tesla at 12.7?MHz MRI and computed tomography (CT) scanning. Fifteen samples of RFID tags with two different sizes (wristband and ID card types) were tested. The tags were exposed to several MR-imaging conditions during MRI examination and X-rays of CT scan. Throughout the test, the tags were oriented in three different directions (axial, coronal, and sagittal) relative to MRI system in order to cover all possible situations with respect to the patient undergoing MRI and CT scanning, wearing a RFID tag on wrist. We observed that the tags did not sustain physical damage with their functionality remaining unaffected even after MRI and CT scanning, and there was no alternation in previously stored data as well. In addition, no evidence of either signal loss or artifact was seen in the acquired MR and CT images. Therefore, we can conclude that the use of this passive RFID tag is safe for a patient undergoing MRI at 0.3 T/12.7?MHz and CT Scanning. PMID:24701187

Periyasamy, M.; Dhanasekaran, R.

2014-01-01

323

LANSCE-R WIRE-SCANNER SYSTEM  

SciTech Connect

The National Instruments cRIO platform is used for the new LANSCE-R wire-scanner systems. All wire-scanner electronics are integrated into a single BiRa BiRIO 4U cRIO chassis specifically designed for the cRIO crate and all interface electronics. The BiRIO chassis, actuator and LabVIEW VIs provide a complete wire-scanner system integrated with EPICS. The new wire-scanner chassis includes an 8-slot cRIO crate with Virtex-5 LX 110 FPGA and Power-PC real-time controller, the LANL-developed cRIO 2-axis wire-sensor analog interface module (AFE), NI9222 cRIO 4-channel 16-bit digitizer, cRIO resolver demodulator, cRIO event receiver, front-panel touch panel display, motor driver, and all necessary software, interface wiring, connectors and ancillary components. This wirescanner system provides a complete, turn-key, 2-axis wire-scanner system including 2-channel low-noise sensewire interface with variable DC wire bias and wireintegrity monitor, 16-bit signal digitizers, actuator motor drive and control, actuator position sensing, limit-switch interfaces, event receiver, LabVIEW and EPICS interface, and both remote operation and full stand-alone operation using the touch panel.

Gruchalla, Michael E. [Los Alamos National Laboratory

2011-01-01

324

76 FR 60118 - Tesla Motors, Inc. Grant of Petition for Renewal of a Temporary Exemption From the Advanced Air...  

Federal Register 2010, 2011, 2012, 2013

...Administration [Docket No. NHTSA-2011-0070] Tesla Motors, Inc. Grant of Petition for Renewal of a...SUMMARY: This notice grants the petition of Tesla Motors, Inc. (Tesla) for the renewal of a temporary exemption of...

2011-09-28

325

Infrared scanner concept verification test report  

NASA Technical Reports Server (NTRS)

The test results from a concept verification test conducted to assess the use of an infrared scanner as a remote temperature sensing device for the space shuttle program are presented. The temperature and geometric resolution limits, atmospheric attenuation effects including conditions with fog and rain, and the problem of surface emissivity variations are included. It is concluded that the basic concept of using an infrared scanner to determine near freezing surface temperatures is feasible. The major problem identified is concerned with infrared reflections which result in significant errors if not controlled. Action taken to manage these errors result in design and operational constraints to control the viewing angle and surface emissivity.

Bachtel, F. D.

1980-01-01

326

Miniature rotating transmissive optical drum scanner  

NASA Technical Reports Server (NTRS)

A miniature rotating transmissive optical scanner system employs a drum of small size having an interior defined by a circumferential wall rotatable on a drum axis, an optical element positioned within the interior of the drum, and a light-transmissive lens aperture provided at an angular position in the circumferential wall of the drum for scanning a light beam to or from the optical element in the drum along a beam azimuth angle as the drum is rotated. The miniature optical drum scanner configuration obtains a wide scanning field-of-view (FOV) and large effective aperture is achieved within a physically small size.

Lewis, Robert (Inventor); Parrington, Lawrence (Inventor); Rutberg, Michael (Inventor)

2013-01-01

327

Report on the TESLA Engineering Study/Review  

SciTech Connect

In March, 2001, the TESLA Collaboration published its Technical Design Report (TDR, see references and links in Appendix), the first sentence of which stated ''...TESLA (TeV-Energy Superconducting Linear Collider) (will be) a superconducting electron-positron collider of initially 500 GeV total energy, extendable to 800 GeV, and an integrated X-ray laser laboratory.'' The TDR included cost and manpower estimates for a 500 GeV e{sup +}e{sup -} collider (250 on 250 GeV) based on superconducting RF cavity technology. This was submitted as a proposal to the German government. The government asked the German Science Council to evaluate this proposal. The recommendation from this body is anticipated to be available by November 2002. The government has indicated that it will react on this recommendation by mid-2003. In June 2001, Steve Holmes, Fermilab's Associate Director for Accelerators, commissioned Helen Edwards and Peter Garbincius to organize a study of the TESLA Technical Design Report and the associated cost and manpower estimates. Since the elements and methodology used in producing the TESLA cost estimate were somewhat different from those used in preparing similar estimates for projects within the U.S., it is important to understand the similarities, differences, and equivalences between the TESLA estimate and U.S. cost estimates. In particular, the project cost estimate includes only purchased equipment, materials, and services, but not manpower from DESY or other TESLA collaborating institutions, which is listed separately. It does not include the R&D on the TESLA Test Facility (TTF) nor the costs of preparing the TDR nor the costs of performing the conceptual studies so far. The manpower for the pre-operations commissioning program (up to beam) is included in the estimate, but not the electrical power or liquid Nitrogen (for initial cooldown of the cryogenics plant). There is no inclusion of any contingency or management reserve. If the U.S. were to become involved with the TESLA project, either as a collaborator for an LC in Germany, or as host country for TESLA in the U.S., it is important to begin to understand the scope and technical details of the project, what R&D still needs to be done, and how the U.S. can contribute. The charge for this study is included in the Appendix to this report.

Cornuelle, John C.

2002-08-30

328

Two-Slotted Surface Coil Array for Magnetic Resonance Imaging at 4 Tesla  

SciTech Connect

Arrays of antennas have been widely accepted for magnetic resonance imaging applications due to their high signal-to-noise ratio (SNR) over large volumes of interest. A new surface coil based on the magnetron tube and called slotted surface coil, has been recently introduced by our group. This coil design experimentally demonstrated a significant improvement over the circular-shaped coil when used in the receive-only mode. The slotted coils formed a two-sheet structure with a 90 deg. separation and each coil had 6 circular slots. Numerical simulations were performed using the finite element method for this coil design to study the behaviour of the array magnetic field. Then, we developed a two-coil array for brain magnetic resonance imaging to be operated at the resonant frequency of 170 MHz in the transceiver mode. Phantom images were acquired with our coil array and standard pulse sequences on a research-dedicated 4 Tesla scanner. Numerical simulations demonstrated that electromagnetic interaction between the coil elements is negligible, and that the magnetic field showed a good uniformity. In vitro images showed the feasibility of this coil array for standard pulses for high field magnetic resonance imaging.

Solis, S. E. [Medical Department, Brookhaven National Laboratory, Upton, N.Y. 11973 (United States); Centro de Investigacion e Instrumentacion e Imagenologia Medica, Universidad Autonoma Metropolitana Iztapalapa, Mexico, DF 09340 (Mexico); Hernandez, J. A.; Rodriguez, A. O. [Centro de Investigacion e Instrumentacion e Imagenologia Medica, Universidad Autonoma Metropolitana Iztapalapa, Mexico, DF 09340 (Mexico); Tomasi, D. [Medical Department, Brookhaven National Laboratory, Upton, N.Y. 11973 (United States)

2008-08-11

329

Multicenter Validation of Spin-Density Projection-Assisted R2-MRI for the Noninvasive Measurement of Liver Iron Concentration  

PubMed Central

Purpose Magnetic resonance imaging (MRI)-based techniques for assessing liver iron concentration (LIC) have been limited by single scanner calibration against biopsy. Here, the calibration of spin-density projection-assisted (SDPA) R2-MRI (FerriScan) in iron-overloaded ?-thalassemia patients treated with the iron chelator, deferasirox, for 12 months is validated. Methods SDPA R2-MRI measurements and percutaneous needle liver biopsy samples were obtained from a subgroup of patients (n?=?233) from the ESCALATOR trial. Five different makes and models of scanner were used in the study. Results LIC, derived from mean of MRI- and biopsy-derived values, ranged from 0.7 to 50.1?mg Fe/g dry weight. Mean fractional differences between SDPA R2-MRI- and biopsy-measured LIC were not significantly different from zero. They were also not significantly different from zero when categorized for each of the Ishak stages of fibrosis and grades of necroinflammation, for subjects aged 3 to <8 versus ?8 years, or for each scanner model. Upper and lower 95% limits of agreement between SDPA R2-MRI and biopsy LIC measurements were 74 and ?71%. Conclusion The calibration curve appears independent of scanner type, patient age, stage of liver fibrosis, grade of necroinflammation, and use of deferasirox chelation therapy, confirming the clinical usefulness of SDPA R2-MRI for monitoring iron overload. Magn Reson Med 71:22152223, 2014. 2013 Wiley Periodicals, Inc. PMID:23821350

St Pierre, Tim G; El-Beshlawy, Amal; Elalfy, Mohsen; Al Jefri, Abdullah; Al Zir, Kusai; Daar, Shahina; Habr, Dany; Kriemler-Krahn, Ulrike; Taher, Ali

2014-01-01

330

3-Tesla magnetic resonance imaging improves the prostate cancer detection rate in transrectral ultrasound-guided biopsy  

PubMed Central

The detection rate of prostate cancer (PCa) using traditional biopsy guided by transrectal ultrasound (TRUS) is not satisfactory. The aim of this study was to determine the utility of 3-Tesla (3-T) magnetic resonance imaging (MRI) prior to TRUS-guided prostate biopsy and to investigate which subgroup of patients had the most evident improvement in PCa detection rate. A total of 420 patients underwent 3-T MRI examination prior to the first prostate biopsy and the positions of suspicious areas were recorded respectively. TRUS-guided biopsy regimes included systematic 12-core biopsy and targeted biopsy identified by MRI. Patients were divided into subgroups according to their serum prostate-specific antigen (PSA) levels, PSA density (PSAD), prostate volume, TRUS findings and digital rectal examination (DRE) findings. The ability of MRI to improve the cancer detection rate was evaluated. The biopsy positive rate of PCa was 41.2% (173/420), and 41 of the 173 (23.7%) patients were detected only by targeted biopsy in the MRI-suspicious area. Compared with the systematic biopsy, the positive rate was significantly improved by the additional targeted biopsy (P=0.0033). The highest improvement of detection rate was observed in patients with a PSA level of 410 ng/ml, PSAD of 0.120.20 ng/ml2, prostate volume >50 ml, negative TRUS findings and negative DRE findings (P<0.05). Therefore, it is considered that 3-T MRI examination could improve the PCa detection rate on first biopsy, particularly in patients with a PSA level of 410 ng/ml, PSAD of 0.120.20 ng/ml2, prostate volume of >50 ml, negative TRUS findings and negative DRE findings.

CHEN, JIE; YI, XIAO-LEI; JIANG, LI-XIN; WANG, REN; ZHAO, JUN-GONG; LI, YUE-HUA; HU, BING

2015-01-01

331

Inter-observer agreement and diagnostic accuracy of myocardial perfusion reserve quantification by cardiovascular magnetic resonance at 3 Tesla in comparison to quantitative coronary angiography  

PubMed Central

Background Quantification of cardiovascular magnetic resonance (CMR) myocardial perfusion reserve (MPR) at 1.5 Tesla has been shown to correlate to invasive evaluation of coronary artery disease (CAD) and to yield good inter-observer agreement. However, little is known about quantitative adenosine-perfusion CMR at 3 Tesla and no data about inter-observer agreement is available. Aim of our study was to evaluate inter-observer agreement and to assess the diagnostic accuracy in comparison to quantitative coronary angiography (QCA). Methods Fifty-three patients referred for coronary x-ray angiography were previously examined in a 3 Tesla whole-body scanner. Adenosine and rest perfusion CMR were acquired for the quantification of MPR in all segments. Two blinded and independent readers analyzed all images. QCA was performed in case of coronary stenosis. QCA data was used to assess diagnostic accuracy of the MPR measurements. Results Inter-observer agreement was high for all myocardial perfusion territories (??=?0.92 for LAD, ??=?0.93 for CX and RCA perfused segments). Compared to QCA receiver-operating characteristics yielded an area under the curve of 0.78 and 0.73 for RCA, 0.66 and 0.69 for LAD, and 0.52 and 0.53 for LCX perfused territories. Conclusions Inter-observer agreement of MPR quantification at 3 Tesla CMR is very high for all myocardial segments. Diagnostic accuracy in comparison to QCA yields good values for the RCA and LAD perfused territories, but moderate values for the posterior LCX perfused myocardial segments. PMID:23537061

2013-01-01

332

Brain iron deposition in essential tremor: a quantitative 3-Tesla magnetic resonance imaging study.  

PubMed

Studies have demonstrated brain iron deposition in neurodegenerative disease and in normal aging. Data on this topic are lacking in essential tremor (ET). The aim of our study was to investigate brain iron content in patients with ET, using quantitative magnetic resonance imaging (MRI) T2*-relaxometry. We enrolled 24 patients with ET and 25 age-matched healthy controls. Subjects were examined using a 3T MRI scanner. The protocol included conventional MRI sequences and quantitative T2*-relaxometry. Whole-brain voxel-based analyses showed significant differences in T2* values in bilateral globus pallidus, substantia nigra, and in right dentate nucleus (P < .001 uncorrected). In the bilateral pallidum, differences survived family-wise-error (FWE) correction for multiple comparisons (P < .05). The present study provides the first evidence of increased brain iron accumulation in ET patients. Our results are suggestive of a possible involvement of motor systems outside of the cerebellum/cerebellar pathway and, more specifically, of the globus pallidus. PMID:23238868

Novellino, Fabiana; Cherubini, Andrea; Chiriaco, Carmelina; Morelli, Maurizio; Salsone, Maria; Arabia, Gennarina; Quattrone, Aldo

2013-02-01

333

PET and MRI: The Odd Couple or a Match Made in Heaven?  

PubMed Central

Positron emission tomography (PET) and magnetic resonance imaging (MRI) are imaging modalities routinely used for clinical and research applications. Integrated scanners capable of acquiring PET and MRI data in the same imaging session, sequentially or simultaneously, have recently become available for human use. In this manuscript, we describe some of the technical advances that allowed the development of human PET/MR scanners, briefly discuss methodological challenges and opportunities provided by this novel technology and present potential oncologic, cardiac, and neuro-psychiatric applications. These examples range from studies that might immediately benefit from PET/MR to more advanced applications where future development might have an even broader impact. PMID:23492887

Catana, Ciprian; Guimaraes, Alexander R.; Rosen, Bruce R.

2013-01-01

334

TESLA: Translation Evaluation of Sentences with Linear-programming-based Analysis  

Microsoft Academic Search

We present TESLA-M and TESLA, two novel automatic machine translation eval- uation metrics with state-of-the-art perfor- mances. TESLA-M builds on the suc- cess of METEOR and MaxSim, but em- ploys a more expressive linear program- ming framework. TESLA further exploits parallel texts to build a shallow seman- tic representation. We evaluate both on the WMT 2009 shared evaluation task and

Chang Liu; Daniel Dahlmeier; Hwee Tou Ng

2010-01-01

335

Correction techniques for a multilevel reflection scanner.  

PubMed

This paper discusses the fundamental problems and design solutions for a multilevel reflection scanner. The scanner consists of a computer, a cathode ray tube light source, a system for imaging the light on the scanned document, two photomultiplier tubes, and a system for digitizing the PMT signals. One PMT measures cathode ray tube radiance while the other intercepts reflected light from the document. The computer controls the intensity focus and position of the spot and processes the digitized photomultiplier tube signals. The three fundamental problems associated with this type of scanner are tonal distortion due to the placement of the PMTs, the differing reflection properties of papers, and PMT drift. Procedures for reducing the effects of these problems, utilizing a computer correction table, are discussed. In addition, a detailed analysis is made of the most serious problem of tonal distortion due to the geometry of the system, and the results of this analysis are compared with experimental results. Finally, a noncomputer associated scanner is described. PMID:20076021

Rosenthal, J A; Serednicky, P

1969-11-01

336

Current segmented gamma-ray scanner technology  

SciTech Connect

A new generation of segmented gamma-ray scanners has been developed at Los Alamos for scrap and waste measurements at the Savannah River Plant and the Los Alamos Plutonium Facility. The new designs are highly automated and exhibit special features such as good segmentation and thorough shielding to improve performance.

Bjork, C.W.

1987-01-01

337

Enriching Scanner Panel Models with Choice Experiments  

Microsoft Academic Search

This research examines the methods, viability, and benefits of pooling scanner panel choice data with compatible preference data from designed choice experiments. The fact that different choice data sources have diverse strengths and weaknesses suggests it might be possible to pool multiple sources to achieve improved models, due to offsetting advantages and disadvantages. For example, new attributes and attribute levels

Joffre Swait; Rick L. Andrews

2003-01-01

338

Holographic Three Dimensional Printer Using Galvanometer Scanners  

Microsoft Academic Search

To make holograms from computer graphic (CG) in a short time, a new holographic three dimensional (3D) printer is proposed here. This printer consists of galvanometer scanners, a micro computer and a laser, and uses a holographic contact duplicating method. Experiments have shown that a hologram of 39 41 mm can be obtained in 4 min.

Masahide Monde; Tsuyoshi Uematsu; Toshiki Toda; Kazuhiko Ohnuma; Yoshizumi Yasuda

1995-01-01

339

Scanner characterization for color measurement and diagnostics  

Microsoft Academic Search

We propose a novel scanner characterization approach for applications requiring color measurement of hardcopy output in calibration, characterization, and diagnostics applications. The method is advantageous for common practical color printing sys- tems that use more than the minimum of three colorants necessary for subtractive color reproduction; printing with cyan (C), magenta (M), yellow (Y), and black (K) is the most

Bong-Sun Lee; Raja Bala; Gaurav Sharma

2007-01-01

340

GEPS: the Gene Expression Pattern Scanner  

Microsoft Academic Search

Gene Expression Pattern Scanner (GEPS) is a web- based server to provide interactive pattern analysis of user-submitted microarray data for facilitating their further interpretation. Putative gene expression patterns such as correlated expression, similar expression and specific expression are determined globally and systematically using geometric com- parison and correlation analysis methods. These patterns can be visualized via linear plot with quan-

Yu-peng Wang; Liang Liang; Bu-cong Han; Yu Quan; Xiao Wang; Tao Tao; Zhi Liang Ji

2006-01-01

341

7 tesla magnetic resonance imaging: A closer look at substantia nigra anatomy in Parkinson's disease.  

PubMed

A hallmark of Parkinson's disease (PD) is the progressive neurodegeneration of dopaminergic neurons in the substantia nigra pars compacta (SNc). Dopaminergic denervation is commonly imaged using radiotracer imaging in target structures such as the striatum. Until recently, imaging made only a modest contribution to detecting neurodegenerative changes in the substantia nigra (SN) directly. Histologically, the SN is subdivided into the ventral pars reticulata and the dorsal pars compacta, which is composed of dopaminergic neurons. In humans, dopaminergic neurons, which are known to accumulate neuromelanin, form clusters of cells (nigrosomes) that penetrate deep into the SN pars reticulata (SNr). The SNr contains higher levels of iron than the SNc in normal subjects. Neuromelanin and T2*-weighted imaging therefore better detect the SNc and the SNr, respectively. The development of ultra-high field 7 Tesla (7T) magnetic resonance imaging (MRI) provided the increase in spatial resolution and in contrast that was needed to detect changes in SN morphology. 7T MRI allows visualization of nigrosome-1 as a hyperintense signal area on T2*-weighted images in the SNc of healthy subjects and its absence in PD patients, probably because of the loss of melanized neurons and the increase of iron deposition. This review is designed to provide a better understanding of the correspondence between the outlines and subdivisions of the SN detected using different MRI contrasts and the histological organization of the SN. The recent findings obtained at 7T will then be presented in relation to histological knowledge. 2014 International Parkinson and Movement Disorder Society. PMID:25308960

Lehricy, Stphane; Bardinet, Eric; Poupon, Cyril; Vidailhet, Marie; Franois, Chantal

2014-11-01

342

In vivo 7 Tesla imaging of the dentate granule cell layer in Schizophrenia  

PubMed Central

PURPOSE The hippocampus is central to the pathophysiology of schizophrenia. Histology shows abnormalities in the dentate granule cell layer (DGCL), but its small size (~100 micron thickness) has precluded in vivo human studies. We used ultra high field magnetic resonance imaging (MRI) to compare DGCL morphology of schizophrenic patients to matched controls. METHOD Bilateral hippocampi of 16 schizophrenia patients (10 male) 40.710.6 years old (mean standard deviation) were imaged at 7 Tesla MRI with heavily T2*-weighted gradient-echo sequence at 232 micron in-plane resolution (0.08 ?L image voxels). Fifteen matched controls (8 male, 35.69.4 years old) and one ex vivo post mortem hippocampus (that also underwent histopathology) were scanned with same protocol. Three blinded neuroradiologists rated each DGCL on a qualitative scale of 1 to 6 (from not discernible to easily visible, appearing dark gray or black) and mean left and right DGCL scores were compared using a non-parametric Mann-Whitney test. RESULTS MRI identification of the DGCL was validated with histopathology. Mean right and left DGCL ratings in patients (3.21.0 and 3.51.2) were not statistically different from controls (3.91.1 and 3.80.8), but patients had a trend for lower right DGCL score (p=0.07), which was significantly associated with patient diagnosis (p=0.05). The optimal 48% sensitivity and 80% specificity for schizophrenia was achieved with a DGCL rating of ?2. CONCLUSION Decreased contrast in the right DGCL in schizophrenia was predictive of schizophrenia diagnosis. Better utility of this metric as a schizophrenia biomarker may be achieved in future studies of patients with homogeneous disease subtypes and progression rates. PMID:23664589

Kirov, Ivan I.; Hardy, Caitlin J.; Matsuda, Kant; Messinger, Julie; Cankurtaran, Ceylan Z.; Warren, Melina; Wiggins, Graham C.; Perry, Nissa N.; Babb, James S.; Goetz, Raymond R.; George, Ajax; Malaspina, Dolores; Gonen, Oded

2013-01-01

343

Biomedical Applications of Sodium MRI In Vivo  

PubMed Central

In this article, we present an up-to-date overview of the potential biomedical applications of sodium MRI in vivo. Sodium MRI is a subject of increasing interest in translational imaging research as it can give some direct and quantitative biochemical information on the tissue viability, cell integrity and function, and therefore not only help the diagnosis but also the prognosis of diseases and treatment outcomes. It has already been applied in vivo in most of human tissues, such as brain for stroke or tumor detection and therapeutic response, in breast cancer, in articular cartilage, in muscle and in kidney, and it was shown in some studies that it could provide very useful new information not available through standard proton MRI. However, this technique is still very challenging due to the low detectable sodium signal in biological tissue with MRI and hardware/software limitations of the clinical scanners. The article is divided in three parts: (1) the role of sodium in biological tissues, (2) a short review on sodium magnetic resonance, and (3) a review of some studies on sodium MRI on different organs/diseases to date. PMID:23722972

Madelin, Guillaume; Regatte, Ravinder R.

2013-01-01

344

21 CFR 892.1300 - Nuclear rectilinear scanner.  

Code of Federal Regulations, 2012 CFR

...rectilinear scanner. (a) Identification. A nuclear rectilinear scanner is a device intended to image the distribution of radionuclides in the body by means of a detector (or detectors) whose position moves in two directions with...

2012-04-01

345

21 CFR 892.1330 - Nuclear whole body scanner.  

Code of Federal Regulations, 2011 CFR

...Diagnostic Devices 892.1330 Nuclear whole body scanner. (a) Identification. A nuclear whole body scanner is a device intended to measure and image the distribution of radionuclides in the body by means of a wide-aperture...

2011-04-01

346

21 CFR 892.1300 - Nuclear rectilinear scanner.  

...rectilinear scanner. (a) Identification. A nuclear rectilinear scanner is a device intended to image the distribution of radionuclides in the body by means of a detector (or detectors) whose position moves in two directions with...

2014-04-01

347

21 CFR 892.1300 - Nuclear rectilinear scanner.  

Code of Federal Regulations, 2013 CFR

...rectilinear scanner. (a) Identification. A nuclear rectilinear scanner is a device intended to image the distribution of radionuclides in the body by means of a detector (or detectors) whose position moves in two directions with...

2013-04-01

348

21 CFR 892.1330 - Nuclear whole body scanner.  

Code of Federal Regulations, 2013 CFR

...Diagnostic Devices 892.1330 Nuclear whole body scanner. (a) Identification. A nuclear whole body scanner is a device intended to measure and image the distribution of radionuclides in the body by means of a wide-aperture...

2013-04-01

349

21 CFR 892.1300 - Nuclear rectilinear scanner.  

Code of Federal Regulations, 2011 CFR

...rectilinear scanner. (a) Identification. A nuclear rectilinear scanner is a device intended to image the distribution of radionuclides in the body by means of a detector (or detectors) whose position moves in two directions with...

2011-04-01

350

21 CFR 892.1330 - Nuclear whole body scanner.  

...Diagnostic Devices 892.1330 Nuclear whole body scanner. (a) Identification. A nuclear whole body scanner is a device intended to measure and image the distribution of radionuclides in the body by means of a wide-aperture...

2014-04-01

351

21 CFR 892.1330 - Nuclear whole body scanner.  

Code of Federal Regulations, 2012 CFR

...Diagnostic Devices 892.1330 Nuclear whole body scanner. (a) Identification. A nuclear whole body scanner is a device intended to measure and image the distribution of radionuclides in the body by means of a wide-aperture...

2012-04-01

352

21 CFR 892.1300 - Nuclear rectilinear scanner.  

Code of Federal Regulations, 2010 CFR

...rectilinear scanner. (a) Identification. A nuclear rectilinear scanner is a device intended to image the distribution of radionuclides in the body by means of a detector (or detectors) whose position moves in two directions with...

2010-04-01

353

21 CFR 892.1330 - Nuclear whole body scanner.  

Code of Federal Regulations, 2010 CFR

...Diagnostic Devices 892.1330 Nuclear whole body scanner. (a) Identification. A nuclear whole body scanner is a device intended to measure and image the distribution of radionuclides in the body by means of a wide-aperture...

2010-04-01

354

23. SITE BUILDING 002 SCANNER BUILDING RADAR CONTROL ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

23. SITE BUILDING 002 - SCANNER BUILDING - RADAR CONTROL INTERFACE "RCL NO. 2" WITH COMPUTER CONTROL DISC DRIVE UNITS IN FOREGROUND. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

355

11. SITE BUILDING 002 SCANNER BUILDING EVAPORATIVE COOLING ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. SITE BUILDING 002 - SCANNER BUILDING - EVAPORATIVE COOLING TOWER SYSTEM IN FOREGROUND. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

356

13. SITE BUILDING 002 SCANNER BUILDING "B" FACE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. SITE BUILDING 002 - SCANNER BUILDING - "B" FACE LOADING DOCK AND PERSONNEL ACCESS RAMP TO FALLOUT SHELTER. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

357

TESLA Report 2005-07 FPGA BASED, FULL-DUPLEX, MULTI-CHANNEL,  

E-print Network

TRANSCEIVER FOR TESLA TECHNOLOGY LLRF CONTROL SYSTEM Krzysztof T. Pozniak, Ryszard S. Romaniuk, Wojciech a comparison between the available protocols of serial data transmission for FPGA technology. This TESLA, distributed measurement and control systems, Warsaw ELHEP Group, TESLA Technology LLRF, DESY, Hamburg Building

358

TESLA Report 2006-07 FPGA based Multichannel Optical Concentrator SIMCON 4.0  

E-print Network

propelling the FEL is presented in fig. 1. The used cavities are of TESLA Technology type [4]. Fig. 1TESLA Report 2006-07 1 FPGA based Multichannel Optical Concentrator SIMCON 4.0 for TESLA cavities, Jaroslaw Szewinski, Ryszard S. Romaniuk Institute of Electronic Systems, Warsaw University of Technology

359

TESLA Report 2003-09 Tomasz Czarski, Ryszard Romaniuk, Krzysztof Pozjniak,  

E-print Network

ISE, Warsaw University of Technology TESLA, DESY, Hamburg Cavity Control System Models' Simulations1/10 TESLA Report 2003-09 Tomasz Czarski, Ryszard Romaniuk, Krzysztof Pozjniak, Warsaw ELHEP Group For TESLA Linear Accelerator ABSTRACT The fundamental knowledge contained in the previous paper "Cavity

360

Tesla Report 2003-34 Distributed Embedded PC Based Control and Data  

E-print Network

Tesla Report 2003-34 Distributed Embedded PC Based Control and Data Acquisition System for TESLA of Technology, ul. Nowowiejska 15/19, 00-665 Warszawa, Poland bInstitute of Experimental Physics, Warsaw acquisition system to be used in TESLA controller and simulator (SIMCON) boards [1]. The standard VME

361

The TESLA Broadcast Authentication Protocol # Adrian Perrig Ran Canetti J. D. Tygar Dawn Song  

E-print Network

The TESLA Broadcast Authentication Protocol # Adrian Perrig Ran Canetti J. D. Tygar Dawn Song presents the TESLA (Timed Efficient Stream Loss­tolerant Authentication) broadcast au­ thentication numbers of receivers, and tolerates packet loss. TESLA is based on loose time synchro­ nization between

Perrig, Adrian

362

LAL/RT 04-03 THE TESLA HIGH POWER COUPLER PROGRAM AT ORSAY  

E-print Network

LAL/RT 04-03 April 2004 1 THE TESLA HIGH POWER COUPLER PROGRAM AT ORSAY T. Garvey, H. Borie, L, Université de Paris-Sud, B.P. 34, 91898 Orsay, France Abstract Within the general TESLA collaboration-Orsay are centred on the development of RF input couplers for the cavities of the TESLA linear collider study

Boyer, Edmond

363

Proving Correctness of the Basic TESLA Multicast Stream Authentication Protocol with TAME  

E-print Network

Proving Correctness of the Basic TESLA Multicast Stream Authentication Protocol with TAME Presented, Washington, DC 20375 E-mail: archer@itd.nrl.navy.mil The TESLA multicast stream authentication protocol just been revealed. While an informal argument for the correctness of TESLA has been published

364

Study of the TESLA preaccelerator for the polarised electron beam Aline Curtoni, Marcel Jablonka,  

E-print Network

Study of the TESLA preaccelerator for the polarised electron beam Aline Curtoni, Marcel Jablonka, CEA, DSM/DAPNIA, Saclay, France Abstract In the mainframe of the TESLA Technical Design Report a study assumed. Figure 1 : Schematic of the TESLA injector complex. This report deals with the bottom injector

365

Forschung an Lepton Collidern Abbildung 49: Perspektivische Ansicht des TESLA-Detektors.  

E-print Network

Forschung an Lepton Collidern Abbildung 49: Perspektivische Ansicht des TESLA-Detektors. 86 #12An- strengung vieler Gruppen und Institute der ,,Tech- nical Design Report" für TESLA veröffentlicht wer- den von TESLA, besonders in Bereichen, die im TDR nicht ausreichend behandelt werden konnten, und die

366

FIRST EXPERIMENTS WITH THE RF GUN BASED INJECTOR FOR THE TESLA TEST FACILITY LINAC  

E-print Network

FIRST EXPERIMENTS WITH THE RF GUN BASED INJECTOR FOR THE TESLA TEST FACILITY LINAC S. Schreiber for the TESLA Collaboration, DESY, 22603 Hamburg, Germany Abstract During 1997 and 1998 a first accelerator module was tested successfully at the TESLA Test Facility Linac (TTFL) at DESY. Eight superconducting

367

Wakefield induced Losses in the Manual Valves of the TESLA Cryomodule  

E-print Network

1 Wakefield induced Losses in the Manual Valves of the TESLA Cryomodule M.Dohlus,H.-P.Wedekind,K.Zapfe DeutschesElektronenSynchrotron Notkestr.85,D-22603Hamburg,Germany Abstract The beam pipe of the TESLA valves with spring type rf-shield which are presently used in the linac of the TESLA Test Facility

368

NHMFL Breaks the 100 Tesla Barrier Gregory S. Boebinger, National High Magnetic Field Laboratory  

E-print Network

NHMFL Breaks the 100 Tesla Barrier Gregory S. Boebinger, National High Magnetic Field Laboratory. 109no. 31 12404-12407 On March 22nd 2012, the NHMFL ­ Pulsed Field Facility broke the 100T tesla barrier, setting a world record of 100.75 tesla for a non-destructive magnet. By using advanced

Weston, Ken

369

TESLA Report 2005-20 8-Channel, FPGA based, DSP Integrated  

E-print Network

TESLA Report 2005-20 8-Channel, FPGA based, DSP Integrated Cavity Simulator & Controller for VUV superconducting, narrowband niobium cavity, originally considered for the TTF and TESLA in DESY, Hamburg (now of the LLRF control system for the TESLA Test Facility (now associated with the VUV FEL machine). The device

370

The Superconducting TESLA Cavities Dedicated to the memory of Bjrn H. Wiik  

E-print Network

The Superconducting TESLA Cavities Dedicated to the memory of Bjørn H. Wiik B. Aune1 , R, California, USA Abstract The conceptional design of the proposed linear electron-positron collider TESLA/m at a quality factor Q0 5 · 109. The design goal for the cavities of the TESLA Test Facility (TTF) linac

Boyer, Edmond

371

Failure Analysis of the Beam Vacuum in the Superconducting Cavities of the TESLA Main Linear Accelerator  

E-print Network

1 Failure Analysis of the Beam Vacuum in the Superconducting Cavities of the TESLA Main Linear Hamburg, Germany Abstract For the long term successful operation of the superconducting TESLA accelerator The beam vacuum system of the TESLA main linear accelerators contains about 20.000 superconducting cavities

372

Strongest non-destructive magnetic field: world record set at 100-tesla level  

E-print Network

- 1 - Strongest non-destructive magnetic field: world record set at 100-tesla level March 22, 2012), the scientists achieved a whopping 100.75 tesla--a magnetic field nearly 100 times more powerful than a junkyard and insulators. The 100-tesla level is roughly equivalent to 2 million times Earth's magnetic field. #12;- 2

373

TESLA-Based Defense Against Pollution Attacks in P2P Systems with Network Coding  

E-print Network

TESLA-Based Defense Against Pollution Attacks in P2P Systems with Network Coding Anh Le, Athina and time asymmetry (as in TESLA [1]) to provide source authentication for the detection scheme and non; pollution; detection; identification; TESLA; homomorphic MAC. I. INTRODUCTION Peer-to-peer (P2P) systems

Markopoulou, Athina

374

Tesla coil discharges guided by femtosecond laser filaments in air Yohann Brelet1  

E-print Network

1 Tesla coil discharges guided by femtosecond laser filaments in air Yohann Brelet1 , Aurélien, Palaiseau, France A Tesla coil generator was designed to produce high voltage pulses oscillating at 100 k experiments of laser guided discharges obtained in air by high voltage bursts delivered by a compact Tesla

Boyer, Edmond

375

LCnote LCPHSM2005001 Determination of beam energy at TESLA using radiative  

E-print Network

LCPHSM2005001 Determination of beam energy at TESLA using radiative return events ARND HINZE DESY Zeuthen at TESLA. It was suggested to use this method to cross check and calibrate the magnet spectrometer used for measurement of the beam energy at TESLA. A preliminary assessment of the statistical and systematic errors

376

Electrical axes of TESLA-type cavities (Theoretical background, development of measurement equipment, measurement results)  

E-print Network

- 1 - Electrical axes of TESLA-type cavities (Theoretical background, development of measurement equipment, measurement results) Anton Labanc, MHF-SL, DESY, January 2008 Abstract Cells in TESLA cavities. A short overview was already published at the TESLA Report 2007-01. This paper brings more details about

377

Tesla: A Transparent, Extensible Session-Layer Framework for End-to-end Network Services  

E-print Network

Tesla: A Transparent, Extensible Session-Layer Framework for End-to-end Network Services by . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Arthur C. Smith Chairman, Department Committee on Graduate Students #12; 2 #12; Tesla: A Transparent of these services, we describe Tesla, a transparent and extensible framework that allows session-layer services

378

Tesla: A Transparent, Extensible Session-Layer Framework for End-to-end Network Services  

E-print Network

Tesla: A Transparent, Extensible Session-Layer Framework for End-to-end Network Services by . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Arthur C. Smith Chairman, Department Committee on Graduate Students #12;2 #12;Tesla: A Transparent of these services, we describe Tesla, a transparent and extensible framework that allows session-layer services

Gummadi, Ramakrishna

379

TESLA: A Transparent, Extensible Session-Layer Architecture for End-to-end Network Services  

E-print Network

TESLA: A Transparent, Extensible Session-Layer Architecture for End-to-end Network Services Jon describes TESLA, a transparent and extensible framework allowing session- layer services to be developed using a high-level flow- based abstraction. TESLA services can be deployed transparently using dynamic

380

The TESLA Broadcast Authentication Protocol Adrian Perrig Ran Canetti J. D. Tygar Dawn Song  

E-print Network

The TESLA Broadcast Authentication Protocol Adrian Perrig Ran Canetti J. D. Tygar Dawn Song presents the TESLA (Timed Efficient Stream Loss-tolerant Authentication) broadcast authentication protocol of receivers, and tolerates packet loss. TESLA is based on loose time synchronization between the sender

Tygar, Doug

381

The TESLA Broadcast Authentication Protocol Adrian Perrig Ran Canetti J. D. Tygar Dawn Song  

E-print Network

The TESLA Broadcast Authentication Protocol Adrian Perrig Ran Canetti J. D. Tygar Dawn Song presents the TESLA (Timed Efficient Stream Loss-tolerant Authentication) broadcast au- thentication numbers of receivers, and tolerates packet loss. TESLA is based on loose time synchro- nization between

Xu, Wenyuan

382

TESLA: A Transparent, Extensible Session-Layer Architecture for End-to-end Network Services  

E-print Network

TESLA: A Transparent, Extensible Session-Layer Architecture for End-to-end Network Services Jon describes TESLA, a transparent and extensible framework allowing session- layer services to be developed using a high-level ¤ow- based abstraction. TESLA services can be deployed transparently using dynamic

Gummadi, Ramakrishna

383

OPERATIONAL EXPERIENCE WITH THE TEST FACILITIES FOR TESLA H. Weise, DESY, Hamburg, Germany  

E-print Network

OPERATIONAL EXPERIENCE WITH THE TEST FACILITIES FOR TESLA H. Weise, DESY, Hamburg, Germany Abstract The TESLA superconducting electron-positron linear collider with an integrated X-ray laser laboratory government in matters of science. In preparation of this, the TESLA Test Facility was set up at DESY. More

384

TESLA Report 2005-04 Modular & reconfigurable common PCB-platform of  

E-print Network

TESLA Report 2005-04 Modular & reconfigurable common PCB-platform of FPGA based LLRF control system for TESLA Test Facility Krzysztof T. Pozniak, Ryszard S. Romaniuk Institute of Electronic Systems in a universal motherboard (MB) for the next generation of LLRF control system for TESLA. The motherboard bases

385

Time Synchronization in Hierarchical TESLA Wireless Sensor Networks  

SciTech Connect

Time synchronization and event time correlation are important in wireless sensor networks. In particular, time is used to create a sequence events or time line to answer questions of cause and effect. Time is also used as a basis for determining the freshness of received packets and the validity of cryptographic certificates. This paper presents secure method of time synchronization and event time correlation for TESLA-based hierarchical wireless sensor networks. The method demonstrates that events in a TESLA network can be accurately timestamped by adding only a few pieces of data to the existing protocol.

Jason L. Wright; Milos Manic

2009-08-01

386

An ultra fast electron beam x-ray tomography scanner  

Microsoft Academic Search

This paper introduces the design of an ultra fast x-ray tomography scanner based on electron beam technology. The scanner has been developed for two-phase flow studies where frame rates of 1 kHz and higher are required. Its functional principle is similar to that of the electron beam x-ray CT scanners used in cardiac imaging. Thus, the scanner comprises an electron

F. Fischer; D. Hoppe; E. Schleicher; G. Mattausch; H. Flaske; R. Bartel; U. Hampel

2008-01-01

387

An ultra fast electron beam x-ray tomography scanner  

Microsoft Academic Search

This paper introduces the design of an ultra fast x-ray tomography scanner based on electron beam technology. The scanner has been developed for two-phase flow studies where frame rates of 1 kHz and higher are required. Its functional principle is similar to that of the electron beam x-ray CT scanners used in cardiac imaging. Thus, the scanner comprises an electron

388

nature methods | VOL.9 NO.6 | JUNE 2012 | 549 news and views  

E-print Network

in the MRI scanner and connected the other end of the optical fiber to an optical set up located outsidenature methods | VOL.9 NO.6 | JUNE 2012 | 549 news and views Schulz et al.1 used a simple optical system to image calcium transients inside the 9.4 tesla MRI scanner: they fixed one end of a single, long

Cai, Long

389

Is dedicated extremity 1.5-T MRI equivalent to standard large-bore 1.5-T MRI for foot and knee examinations?  

PubMed

OBJECTIVE. The purpose of this study was to prospectively compare dedicated extremity MRI and standard large-bore MRI of the lower extremities in the same patients. SUBJECTS AND METHODS. Sixty-nine patients (27 feet and 42 knees) were examined both with extremity 1.5-T MRI and standard 1.5-T MRI. Scanning duration was measured, and patients completed a detailed questionnaire after each examination (4-point scale). Two readers assessed image quality parameters. Data were analyzed with the paired Student t test, Wilcoxon signed rank test, and chi-square test. RESULTS. Scanning duration was significantly longer for extremity MRI (foot, 29.9 5.5 minutes; knee, 30.4 5.6 minutes) than for standard MRI (foot, 21.9 5.0 minutes; knee, 20.5 3.9 minutes) (p <0.001 for all comparisons). Acoustic noise reported by the patient was significantly lower on extremity MRI (foot, 1.9 0.9; knee, 2.1 0.7) compared with standard MRI (foot, 2.9 1.0; knee, 2.9 0.8) (p <0.001 for all). Patient satisfaction for both systems was high (1.4-1.6 for all, p = 0.2-1.0). Image quality and fat suppression were equally good for both scanners for foot examinations (p ? 0.48). Knee examinations generally featured good image quality on both systems, but standard MRI had superior image quality (p ? 0.01) and fat suppression (p ? 0.001) compared with extremity MRI. More motion artifacts were present on extremity MRI than on standard MRI, which was significant for the knee (p ? 0.04) but not for the foot (p ? 0.32). CONCLUSION. Extremity MRI featured less acoustic noise than standard MRI, but examination duration was longer on extremity MRI. Patient satisfaction was high for both scanners. For foot examinations, image quality on extremity MRI was equivalent to standard MRI. Image quality for knee examinations was better on standard MRI compared with extremity MRI, but overall it was good on both systems. PMID:25415708

Sutter, Reto; Tresch, Florian; Buck, Florian M; Pfirrmann, Christian W A

2014-12-01

390

Design of a Second Generation Firewire Based Data Acquisition System for Small Animal PET Scanners.  

PubMed

The University of Washington developed a Firewire based data acquisition system for the MiCES small animal PET scanner. Development work has continued on new imaging scanners that require more data channels and need to be able to operate within a MRI imaging system. To support these scanners, we have designed a new version of our data acquisition system that leverages the capabilities of modern field programmable gate arrays (FPGA). The new design preserves the basic approach of the original system, but puts almost all functions into the FPGA, including the Firewire elements, the embedded processor, and pulse timing and pulse integration. The design has been extended to support implementation of the position estimation and DOl algorithms developed for the cMiCE detector module. The design is centered around an acquisition node board (ANB) that includes 65 ADC channels, Firewire 1394b support, the FPGA, a serial command bus and signal lines to support a rough coincidence window implementation to reject singles events from being sent on the Firewire bus. Adapter boards convert detector signals into differential paired signals to connect to the ANB. PMID:20228958

Lewellen, T K; Miyaoka, R S; Macdonald, L R; Haselman, M; Dewitt, D; Hunter, William; Hauck, S

2008-10-19

391

TESLA Report 2003-21 Cavity Control System Optimization Methods  

E-print Network

stabilization in the cavity, during flattop period. The introductory analysis of the cavity operational modes accelerators, control theory, free electron laser 1. INTRODUCTION The LLRF (Low Level Radio Frequency) cavityTESLA Report 2003-21 Cavity Control System ­ Optimization Methods For Single Cavity Driving

392

Modern Astronomical Techniques (ASTR 257), Spring 2013 Instructor: Tesla Jeltema  

E-print Network

11. Non-photon signals: neutrinos, cosmic rays, gravity waves #12;Schedule Notes: Professor ProfumoModern Astronomical Techniques (ASTR 257), Spring 2013 Instructor: Tesla Jeltema Office: ISB 305 "Handbook of CCD Astronomy - Howell "Handbook of X-ray Astronomy - Arnaud, Smith, Siemingowska "Data

California at Santa Cruz, University of

393

RF generalization and control for the TESLA TEST FACILITY  

NASA Astrophysics Data System (ADS)

The RF needs for the TESLA Test Facility a DESY are described. Possible klystron-modulator schemes, the waveguide RF distribution system, phase and amplitude control, beam loading, and a scheme to cope with detuning of the cavities due to Lorentz forces are described. Finally, some persectives for the development of new RF sources are discussed. (AIP)

Gamp, Alexander

1995-07-01

394

Tesla Demonstration for Crown College at UCSC Monday, October 22  

E-print Network

Tesla Demonstration for Crown College at UCSC Monday, October 22 nd Schedule Load Time: 3:30pm Arrival at Destination: 4:00pm (Un-load & Set-Up) Demo Time: 5:00pm Dinner @ Dining Hall: 6:00pm Return ___________________________________________________________ Contact: Sally Gaynor, 459-2412, sgaynor@ucsc.edu Address: Crown College, Merrill Cultural Center Driving

California at Santa Cruz, University of

395

Compact and repetitive Tesla-based power source  

Microsoft Academic Search

This paper details the development of a very compact (diameter = 100 mm, length = 840 mm) battery powered, high repetition rate pulsed power source. Tesla technology is employed in the generation of a high output voltage and the source is capable of producing voltage pulses of up to 250 kV. Details are given of the conductor topology adopted to

B. M. Novac; P. Sarkar; I. R. Smith; C. Greenwood

2009-01-01

396

High gain proportional rf control stability at TESLA cavities  

Microsoft Academic Search

Fast proportional rf control is used as the basis for rf field regulation in actual linear accelerator projects like the international linear collider (ILC) and the European x-ray free electron laser (XFEL) based on TESLA technology. Additional control loops improve the field regulation by treating repetitive effects and compensating the beam loading. Nevertheless, the ability for high gain operation of

Elmar Vogel

2007-01-01

397

Identifying Needed Technical Standards: The LITA TESLA Committee at Work.  

ERIC Educational Resources Information Center

Efforts of the Technical Standards for Library Automation Committee (TESLA), a division-wide committee of the Library Information and Technology Association (LITA) of the American Library Association, are described. The current status of suggested technical standards and recommended action are detailed. Five sources are given. (Author/EJS)

Carter, Ruth C.

1984-01-01

398

Beam-Based Alignment of the TESLA Main Linac  

SciTech Connect

The main obstacle to emittance preservation in the main linac of a linear collider is the alignment of the quadrupoles and accelerating cavities with respect to the beam. The misalignment tolerances in the case of the TESLA superconducting main linac are reviewed. Simulations of possible beam-based alignment algorithms to meet these tolerances are presented.

Tenenbaum, Peter G.

2002-06-21

399

Searchers for a new energy source: Tesla, Moray, and Bearden  

Microsoft Academic Search

The work of three leaders in the search for a new energy source, spanning a full century, is examined. Nikola Tesla, T. Henry Moray, and Thomas E. Bearden, among others, have claimed the existence of another source of energy besides those presently in use. This source is the energy contained in apparently empty space. The concepts of each of the

Gary L. Johnson

1992-01-01

400

Nikola Tesla: why was he so much resisted and forgotten?  

Microsoft Academic Search

The amount of published material about Tesla is enormous (thus, he is less forgotten than I thought). The number, importance, and transcendence of his inventions and doings are overwhelming, yet current recognition does not seem to abound, although during his lifetime he did indeed receive many honors. Why then this state of oblivion? What happened? Can history be so blatantly

M. E. Valentinuzzi

1998-01-01

401

Nikola Tesla The creator of the electric age  

Microsoft Academic Search

Nikola Tesla was one of the greatest inventors of all times. He can be placed along with Faraday and Edison as a prolific\\u000a inventor who touched on almost every aspect of electricity. In fact he invented electricity as we know it today and hence\\u000a ushered in the modern age.

Anil K Rajvanshi

2007-01-01

402

A Tree-Based TESLA Broadcast Authentication for Sensor Networks Donggang Liu Peng Ning Sencun Zhu Sushil Jajodia  

E-print Network

A Tree-Based µTESLA Broadcast Authentication for Sensor Networks Donggang Liu Peng Ning Sencun Zhu to multiple nodes in an authenticated way. µTESLA and multi-level µTESLA have been proposed to provide of senders. Though multi-level µTESLA schemes can scale up to large sensor networks (in terms of receivers

Zhu, Sencun

403

76 FR 33402 - Tesla Motors, Inc.; Receipt of Petition for Renewal of Temporary Exemption from the Advanced Air...  

Federal Register 2010, 2011, 2012, 2013

...Administration [Docket No. NHTSA-2011-0070] Tesla Motors, Inc.; Receipt of Petition for...with the procedures in 49 CFR Part 555, Tesla Motors, Inc., has petitioned the agency...and the procedures in 49 CFR Part 555, Tesla Motors, Inc., (Tesla) has...

2011-06-08

404

Automatic Brachytherapy Seed Placement Under MRI Guidance  

PubMed Central

The paper presents a robotic method of performing low dose rate prostate brachytherapy under magnetic resonance imaging (MRI) guidance. The design and operation of a fully automated MR compatible seed injector is presented. This is used with the MrBot robot for transperineal percutaneous prostate access. A new image-registration marker and algorithms are also presented. The system is integrated and tested with a 3T MRI scanner. Tests compare three different registration methods, assess the precision of performing automated seed deployment, and use the seeds to assess the accuracy of needle targeting under image guidance. Under the ideal conditions of the in vitro experiments, results show outstanding image-guided needle and seed placement accuracy. PMID:17694871

Patriciu, Alexandru; Petrisor, Doru; Muntener, Michael; Mazilu, Dumitru; Schar, Michael; Stoianovici, Dan

2011-01-01

405

Ghost Signals In Allison Emittance Scanners  

SciTech Connect

For over 20 years, Allison scanners have been used to measure emittances of low-energy ion beams. We show that scanning large trajectory angles produces ghost signals caused by the sampled beamlet impacting on an electric deflection plate. The ghost signal strength is proportional to the amount of beam entering the scanner. Depending on the ions, and their velocity, the ghost signals can have the opposite or the same polarity as the main beam signals. The ghost signals cause significant errors in the emittance estimates because they appear at large trajectory angles. These ghost signals often go undetected because they partly overlap with the real signals, are mostly below the 1% level, and often hide in the noise. A simple deflection plate modification is shown to reduce the ghost signal strength by over 99%.

Stockli, Martin P. [SNS, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Department of Physics, University of Tennessee, Knoxville, TN 37996 (United States); Leitner, M.; Keller, R. [SNS, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA, 94720 (United States); Moehs, D.P. [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Welton, R. F. [SNS, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States)

2005-03-15

406

Compact conscious animal positron emission tomography scanner  

DOEpatents

A method of serially transferring annihilation information in a compact positron emission tomography (PET) scanner includes generating a time signal for an event, generating an address signal representing a detecting channel, generating a detector channel signal including the time and address signals, and generating a composite signal including the channel signal and similarly generated signals. The composite signal includes events from detectors in a block and is serially output. An apparatus that serially transfers annihilation information from a block includes time signal generators for detectors in a block and an address and channel signal generator. The PET scanner includes a ring tomograph that mounts onto a portion of an animal, which includes opposing block pairs. Each of the blocks in a block pair includes a scintillator layer, detection array, front-end array, and a serial encoder. The serial encoder includes time signal generators and an address signal and channel signal generator.

Schyler, David J. (Bellport, NY); O'Connor, Paul (Bellport, NY); Woody, Craig (Setauket, NY); Junnarkar, Sachin Shrirang (Sound Beach, NY); Radeka, Veljko (Bellport, NY); Vaska, Paul (Sound Beach, NY); Pratte, Jean-Francois (Stony Brook, NY); Volkow, Nora (Chevy Chase, MD)

2006-10-24

407

Detector Position Estimation for PET Scanners  

PubMed Central

Physical positioning of scintillation crystal detector blocks in Positron Emission Tomography (PET) scanners is not always exact. We test a proof of concept methodology for the determination of the six degrees of freedom for detector block positioning errors by utilizing a rotating point source over stepped axial intervals. To test our method, we created computer simulations of seven Micro Crystal Element Scanner (MiCES) PET systems with randomized positioning errors. The computer simulations show that our positioning algorithm can estimate the positions of the block detectors to an average of one-seventh of the crystal pitch tangentially, and one-third of the crystal pitch axially. Virtual acquisitions of a point source grid and a distributed phantom show that our algorithm improves both the quantitative and qualitative accuracy of the reconstructed objects. We believe this estimation algorithm is a practical and accurate method for determining the spatial positions of scintillation detector blocks. PMID:22505789

Pierce, Larry; Miyaoka, Robert; Lewellen, Tom; Alessio, Adam; Kinahan, Paul

2012-01-01

408

Ghost signals in Allison emittance scanners  

SciTech Connect

For over 20 years, Allison scanners have been used to measure emittances of low-energy ion beams. We show that scanning large trajectory angles produces ghost signals caused by the sampled beamlet impacting on an electric deflection plate. The ghost signal strength is proportional to the amount of beam entering the scanner. Depending on the ions, and their velocity, the ghost signals can have the opposite or the same polarity as the main beam signals. The ghost signals cause significant errors in the emittance estimates because they appear at large trajectory angles. These ghost signals often go undetected because they partly overlap with the real signals, are mostly below the 1% level, and often hide in the noise. A simple deflection plate modification is shown to reduce the ghost signal strength by over 99%.

Stockli, Martin P.; /SNS Project, Oak Ridge /Tennessee U.; Leitner, M.; /LBL, Berkeley; Moehs, D.P.; /Fermilab; Keller, R.; /LBL, Berkeley; Welton, R.F.; /SNS Project, Oak

2004-12-01

409

Improvement in measurement accuracy for hybrid scanner  

NASA Astrophysics Data System (ADS)

The capability to provide dense three-dimensional (3D) data (point clouds) at high speed and at high accuracy has made terrestrial laser scanners (TLS) widely used for many purposes especially for documentation, management and analysis. However, similar to other 3D sensors, proper understanding regarding the error sources is necessary to ensure high quality data. A procedure known as calibration is employed to evaluate these errors. This process is crucial for TLS in order to make it suitable for accurate 3D applications (e.g. industrial measurement, reverse engineering and monitoring). Two calibration procedures available for TLS: 1) component, and 2) system calibration. The requirements of special laboratories and tools which are not affordable by most TLS users have become principle drawback for component calibration. In contrast, system calibration only requires a room with appropriate targets. By employing optimal network configuration, this study has performed system calibration through self-calibration for Leica ScanStation C10 scanner. A laboratory with dimensions of 15.5 m 9 m 3 m and 138 well-distributed planar targets were used to derive four calibration parameters. Statistical analysis (e.g. t-test) has shown that only two calculated parameters, the constant rangefinder offset error (0.7 mm) and the vertical circle index error (-45.4") were significant for the calibrated scanner. Photogrammetric technique was utilised to calibrate the 3D test points at the calibration field. By using the test points, the residual pattern of raw data and self-calibration results were plotted into the graph to visually demonstrate the improvement in accuracy for Leica ScanStation C10 scanner.

Abbas, M. A.; Setan, H.; Majid, Z.; Chong, A. K.; Lichti, D. D.

2014-02-01

410

Application of airborne laser scanner - aerial navigation  

Microsoft Academic Search

This dissertation explores the use of an Airborne Laser Scanner (ALS) for use in aircraft Terrain-Referenced Navigation (TRN). Position estimation techniques developed in this dissertation enable the use of large sets of high accuracy ALS measurements to solve for position in real-time. The explored techniques were then used to design, implement, and---for the first time ever---fly a real-time ALS-based TERRain

Jacob L. Campbell

2006-01-01

411

Laser Wire Scanner Development on CTF II  

Microsoft Academic Search

A laser wire scanner is under development at CERN in the framework of the Compact Linear Collider study (CLIC). A first test has been carried out at the CLIC Test Facility II (CTF II) with the aim of developing a beam profile monitor for a low energy, high charge electron beam. In our set-up a 2.5 mJ, 1047 nm, 4

Jacques Bosser; H. H. Braun; Enrico Bravin; T E D'Amico; Steffen Dbert; S Hutchins; T Lefvre; R MacCaferri; G Penn; G A Blair; T Kamps

2002-01-01

412

Point Relay Scanner Utilizing Ellipsoidal Mirrors  

NASA Technical Reports Server (NTRS)

A scanning system uses a polygonal mirror assembly with each facet of the polygon having an ellipsoidal mirror located thereon. One focal point of each ellipsoidal mirror is located at a common point on the axis of rotation of the polygonal mirror assembly. As the mirror assembly rotates. a second focal point of the ellipsoidal mirrors traces out a scan line. The scanner can be utilized for scanned output display of information or for scanning information to be detected.

Manhart, Paul K. (Inventor); Pagano, Robert J. (Inventor)

1997-01-01

413

Learning and teaching with a computer scanner  

NASA Astrophysics Data System (ADS)

This paper introduces the readers to simple inquiry-based activities (experiments with supporting questions) that one can do with a computer scanner to help students learn and apply the concepts of relative motion in 1 and 2D, vibrational motion and the Doppler effect. We also show how to use these activities to help students think like scientists. They will conduct simple experiments, construct different explanations for their observations, test their explanations in new experiments and represent their ideas in multiple ways.

Planinsic, G.; Gregorcic, B.; Etkina, E.

2014-09-01

414

Development of a 7T MRI compatible robot to investigate bodily awareness Background  

E-print Network

, can be very difficult for neurological patients suffering from the so called out-of- body after is to design, develop and test a MR compatible device to be used in the 7Tesla fMRI - one of the most powerful will be an adaptation of a 3T MR compatible robotic device developed between the ReLab and our laboratory (Ionta et al

Daraio, Chiara

415

Tactile Motion and Pattern Processing Assessed with High-Field fMRI  

Microsoft Academic Search

Processing of motion and pattern has been extensively studied in the visual domain, but much less in the somatosensory system. Here, we used ultra-high-field functional magnetic resonance imaging (fMRI) at 7 Tesla to investigate the neuronal correlates of tactile motion and pattern processing in humans under tightly controlled stimulation conditions. Different types of dynamic stimuli created the sensation of moving

Evelin Wacker; Bernhard Spitzer; Ralf Ltzkendorf; Johannes Bernarding; Felix Blankenburg; Michael Breakspear

2011-01-01

416

Biomedical applications of a real-time terahertz color scanner  

PubMed Central

A real-time THz color scanner has the potential to further expand the application scope of THz spectral imaging based on its rapid image acquisition rate. We demonstrated three possible applications of a THz color scanner in the biomedical field: imaging of pharmaceutical tablets, human teeth, and human hair. The first application showed the scanners potential in total inspection for rapid quality control of pharmaceutical tablets moving on a conveyor belt. The second application demonstrated that the scanner can be used to identify a potential indicator for crystallinity of dental tissue. In the third application, the scanner was successfully used to visualize the drying process of wet hairs. These demonstrations indicated the high potential of the THz color scanner for practical applications in the biomedical field. PMID:21258472

Schirmer, Markus; Fujio, Makoto; Minami, Masaaki; Miura, Jiro; Araki, Tsutomu; Yasui, Takeshi

2010-01-01

417

Arterial spin labeling MRI reproducibly measures peak-exercise calf muscle perfusion in healthy volunteers and patients with peripheral arterial disease  

PubMed Central

Objectives We hypothesized that arterial spin labeling (ASL) magnetic resonance imaging (MRI) at 3 Tesla (T) would be a reliable non-contrast technique for measuring peak exercise calf muscle blood flow in both healthy volunteers and patients with peripheral arterial disease (PAD) and will discriminate between these groups. Background Prior work demonstrated the utility of first-pass gadolinium-enhanced calf muscle perfusion MRI in patients with PAD. However, patients with PAD often have advanced renal disease and cannot receive gadolinium. Methods PAD patients had claudication and an ankle brachial index 0.40.9. Age-matched normal subjects (NL) had no PAD risk factors and were symptom-free with exercise. All performed supine plantar flexion exercise in a 3T MRI scanner using a pedal ergometer until exhaustion or limiting symptoms and were imaged at peak exercise with 15 averaged ASL images. Peak perfusion was measured from ASL blood flow images by placing a region of interest in the calf muscle region with the greatest signal intensity. Perfusion was compared between PAD and NL and repeat testing was performed in 12 subjects (5 NL, 7 PAD) for assessment of reproducibility. Results Peak exercise calf perfusion (meanSD) of 15 NL (age 549 years) was higher than in 15 PAD (age 645 years, ABI 0.700.14) (8023mL/min-100g vs. 4916mL/min-100g, p<0.001). Five NL performed exercise matched to PAD and again demonstrated higher perfusion (8425mL/min-100g, p<0.002). As a measure of reproducibility, intra-class correlation coefficient between repeated studies was 0.87 (95% CI 0.610.96). Inter-observer reproducibility was 0.96 (95% CI 0.840.99). Conclusions ASL is a reproducible non-contrast technique for quantifying peak exercise blood flow in calf muscle. Independent of exercise time, ASL discriminates between NL and PAD. This technique may prove useful for clinical trials of therapies for improving muscle perfusion, especially in patients unable to receive gadolinium. PMID:23236972

West, Amy M.; Meyer, Craig H.; Epstein, Frederick H.; Jiji, Ronny; Hunter, Jennifer R.; DiMaria, Joseph M.; Christopher, John M.; Kramer, Christopher M.

2012-01-01

418

In Amnio MRI of Mouse Embryos  

PubMed Central

Mouse embryo imaging is conventionally carried out on ex vivo embryos excised from the amniotic sac, omitting vital structures and abnormalities external to the body. Here, we present an in amnio MR imaging methodology in which the mouse embryo is retained in the amniotic sac and demonstrate how important embryonic structures can be visualised in 3D with high spatial resolution (100 m/px). To illustrate the utility of in amnio imaging, we subsequently apply the technique to examine abnormal mouse embryos with abdominal wall defects. Mouse embryos at E17.5 were imaged and compared, including three normal phenotype embryos, an abnormal embryo with a clear exomphalos defect, and one with a suspected gastroschisis phenotype. Embryos were excised from the mother ensuring the amnion remained intact and stereo microscopy was performed. Embryos were next embedded in agarose for 3D, high resolution MRI on a 9.4T scanner. Identification of the abnormal embryo phenotypes was not possible using stereo microscopy or conventional ex vivo MRI. Using in amnio MRI, we determined that the abnormal embryos had an exomphalos phenotype with varying severities. In amnio MRI is ideally suited to investigate the complex relationship between embryo and amnion, together with screening for other abnormalities located outside of the mouse embryo, providing a valuable complement to histology and existing imaging methods available to the phenotyping community. PMID:25330230

Roberts, Thomas A.; Norris, Francesca C.; Carnaghan, Helen; Savery, Dawn; Wells, Jack A.; Siow, Bernard; Scambler, Peter J.; Pierro, Agostino; De Coppi, Paolo; Eaton, Simon; Lythgoe, Mark F.

2014-01-01

419

Robust Non-Rigid Registration to Capture Brain Shift from Intra-Operative MRI  

E-print Network

-operative MR scanner enhances the surgeon's view and enables the visualization of the brain deformation during is an important source of error that needs to be considered [7]. Indeed, imaging the brain during the procedure1 Robust Non-Rigid Registration to Capture Brain Shift from Intra-Operative MRI Olivier Clatz, Herv

Ayache, Nicholas

420

Quantitative Clinical Evaluation of a Simultaneous PETI MRI Breast Imaging System  

SciTech Connect

A prototype simultaneous PET-MRI breast scanner has been developed for conducting clinical studies with the goal of obtaining high resolution anatomical and functional information in the same scan which can lead to faster and better diagnosis, reduction of unwanted biopsies, and better patient care.

Schlyer D. J.; Schlyer, D.J.

2013-04-03

421

Removal of Confounding Effects of Global Signal in Functional MRI Analyses  

Microsoft Academic Search

Local signals obtained from BOLD fMRI are generally confounded by global effects. In this paper, we make an essential distinction between global effects and the global signal. Global effects have a similar influence on local signals from a large proportion of cerebral voxels. They may reflect diffuse physiological processes or variations in scanner sensitivity and are difficult to measure directly.

Adrien E. Desjardins; Kent A. Kiehl; Peter F. Liddle

2001-01-01

422

MRI of Nonischemic Cardiomyopathy  

PubMed Central

OBJECTIVE The purpose of this article is to present current clinical and research issues in MRI evaluation of nonischemic cardiomyopathy, a diverse set of diseases, many of which have a genetic basis. CONCLUSION Cardiac cine MRI along with delayed myocardial enhancement MRI and other MRI techniques can provide information beyond echocardiography for tissue characterization. MRI is increasingly being used for evaluation of genetically positive, phenotypically negative patients as well as for risk stratification. PMID:20858821

Bluemke, David A.

2010-01-01

423

Imaging and analysis of lenticulostriate arteries using 7.0-Tesla magnetic resonance angiography.  

PubMed

The purpose of this study was to analyze human lenticulostriate arteries (LSAs) obtained non-invasively by 7.0-T MRI. A three-dimensional time-of-flight (3D TOF) magnetic resonance angiography (MRA) technique was used with an investigational 7.0-T MRI scanner with a radio-frequency coil that was optimized and designed for angiographic purposes. We obtained images from 16 healthy volunteers (8 males and 8 females, mean age 21 +/- 2.7 years). For direct comparison of LSA images with digital subtraction angiography (DSA), we also obtained 7.0-T MRA and DSA images from one patient, a 27-year-old woman with a posterior fossa arteriovenous malformation (AVM). We then analyzed the characteristics of LSAs using a custom data analysis method with MatLab for quantitative analysis. Analysis of LSA images included shape and number of branches and origins, findings that are essential and useful for quantification of LSA abnormalities in both healthy controls and patients. Ultra-high-field MRA provided clear anatomic delineation of the LSAs, thereby suggesting that 7.0-T MRA may be a promising technique for microvascular imaging of the LSAs. PMID:19097221

Kang, Chang-Ki; Park, Cheol-Wan; Han, Jae-Yong; Kim, Sang-Hoon; Park, Chan-A; Kim, Kyoung-Nam; Hong, Suk-Min; Kim, Young-Bo; Lee, Kendall H; Cho, Zang-Hee

2009-01-01

424

THE RF-GUN BASED INJECTOR FOR THE TESLA TESTFACILITY LINAC S. Schreiber for the TESLA Collaboration, DESY, 22603 Hamburg, Germany  

E-print Network

THE RF-GUN BASED INJECTOR FOR THE TESLA TESTFACILITY LINAC S. Schreiber for the TESLA Collaboration was produced by a subharmonic injector using a thermionic gun, a buncher cavity, and one standard Linear Collider, a laser driven RF gun is required. At present, two similar guns are under con- struction

425

Retrieval, Monitoring, and Control Processes: A 7 Tesla fMRI Approach to Memory Accuracy  

PubMed Central

Memory research has been guided by two powerful metaphors: the storehouse (computer) and the correspondence metaphor. The latter emphasizes the dependability of retrieved mnemonic information and draws upon ideas about the state dependency and reconstructive character of episodic memory. We used a new movie to unveil the neural correlates connected with retrieval, monitoring, and control processes, and memory accuracy (MAC), according to the paradigm of Koriat and Goldsmith (1996a,b). During functional magnetic resonance imaging, subjects performed a memory task which required (after an initial learning phase) rating true and false statements [retrieval phase (RP)], making confidence judgments in the respective statement [monitoring phase (MP)], and deciding for either venturing (volunteering) the respective answer or withholding the response [control phase (CP)]. Imaging data pointed to common and unique neural correlates. Activations in brain regions related to RP and MAC were observed in the precuneus, middle temporal gyrus, and left hippocampus. MP was associated with activation in the left anterior and posterior cingulate cortex along with bilateral medial temporal regions. If an answer was volunteered (as opposed to being withheld) during the CP, temporal, and frontal as well as middle and posterior cingulate areas and the precuneus revealed activations. Increased bilateral hippocampal activity was found during withholding compared to volunteering answers. The left caudate activation detected during withholding compared to venturing an answer supports the involvement of the left caudate in inhibiting unwanted responses. Contrary to expectations, we did not evidence prefrontal activations during withholding (as opposed to volunteering) answers. This may reflect our design specifications, but alternative interpretations are put forth. PMID:23580061

Risius, Uda-Mareke; Staniloiu, Angelica; Piefke, Martina; Maderwald, Stefan; Schulte, Frank P.; Brand, Matthias; Markowitsch, Hans J.

2012-01-01

426

Novel 16-Channel Receive Coil Array for Accelerated Upper Airway MRI at 3 Tesla  

E-print Network

a noninvasive assessment of speech and swallowing disorders and sleep apnea. Recent work has demonstrated with obstructive sleep apnea (1,2) and swallowing disorders (3). In sleep apnea stud- ies, rapid volumetric imaging disorders. This enables improved assessment of the dynamics of a bolus of food without introducing motion

Southern California, University of

427

Detection of the early negative response in fMRI at 1.5 Tesla  

Microsoft Academic Search

Recent experimental studies have revealed an initial decrease in magnetic resonance (MR) signal that is consistent with optical imaging results. This initial response, thought to arise from a transient increase in deoxyhemoglobin concentration, is prob- ably more localized to the site of neuronal activation. However, with MR imaging, this early response has only been demon- strated at high fields. In

E. Yacoub; X. Hu

1999-01-01

428

Fast wire scanner for intense electron beams  

NASA Astrophysics Data System (ADS)

We have developed a cost-effective, fast rotating wire scanner for use in accelerators where high beam currents would otherwise melt even carbon wires. This new design uses a simple planetary gear setup to rotate a carbon wire, fixed at one end, through the beam at speeds in excess of 20 m/s. We present results from bench tests, as well as transverse beam profile measurements taken at Cornell's high-brightness energy recovery linac photoinjector, for beam currents up to 35 mA.

Moore, T.; Agladze, N. I.; Bazarov, I. V.; Bartnik, A.; Dobbins, J.; Dunham, B.; Full, S.; Li, Y.; Liu, X.; Savino, J.; Smolenski, K.

2014-02-01

429

Recent advances in segmented gamma scanner analysis  

SciTech Connect

The segmented gamma scanner (SGS) is used in many facilities to assay low-density scrap and waste generated in the facilities. The procedures for using the SGS can cause a negative bias if the sample does not satisfy the assumptions made in the method. Some process samples do not comply with the assumptions. This paper discusses the effect of the presence of lumps on the SGS assay results, describes a method to detect the presence of lumps, and describes an approach to correct for the lumps. Other recent advances in SGS analysis are also discussed.

Sprinkle, J.K. Jr.; Hsue, S.T.

1987-01-01

430

MRI of the anterior optic pathways following enucleation.  

PubMed

We examined five patients who had enucleation of one eye for inflammatory or neoplastic disease, using MRI at 1.5 Tesla. None had symptoms referable to the enucleated orbit. In addition, age- and-sex matched individuals were imaged as control subjects, and a further 15 subjects, referred for other than orbital disease, were reviewed. Measurements were made retrospectively of the dimensions of the optic chiasm to establish normal values. All five patients showed abnormalities on MRI following enucleation: abnormal signal within the optic nerve remnant on short tau inversion recovery (STIR) images, and atrophy of the nerve remnant and the chiasm. These findings were not apparent in the control or normal subjects. Such findings are to be expected following enucleation and should not be interpreted as indicating active pathology. PMID:9406209

Hardman, J; Halpin, S F; Hourihan, M D; Mars, S; Lane, C

1997-11-01

431

High gain proportional rf control stability at TESLA cavities  

NASA Astrophysics Data System (ADS)

Fast proportional rf control is used as the basis for rf field regulation in actual linear accelerator projects like the international linear collider (ILC) and the European x-ray free electron laser (XFEL) based on TESLA technology. Additional control loops improve the field regulation by treating repetitive effects and compensating the beam loading. Nevertheless, the ability for high gain operation of the fast loops is desirable for the strong suppression of nonpredictive and nonrepetitive disturbances. TESLA cavities host nine fundamental modes (FMs) where only one is used for beam acceleration. The unwanted FMs have a significant influence on the proportional rf control loop stability at high gains. Within this paper, the stability of proportional rf control loops taking the FMs and digitalization effects into account will be discussed in detail together with measures enabling a significant increase of the gain values.

Vogel, Elmar

2007-05-01

432

Tesla Turbine from Old Hard Drives and Minimal Tools  

NSDL National Science Digital Library

This page provides step by step instructions on building a Tesla turbine from two old computer hard disk drives using basic hand tools and a pillar drill. No metal lathe or other expensive fabrication machinery is required and you only need some basic craft skills. It's crude, but this thing can scream! Tesla Turbines promise up to 92% efficiency of converting air or fluid flow to rotational energy and its use can also be inverted for use as a pump with exceptionally high efficiency too. With compressed air becoming recognized as a feasible form of energy storage, we can see this device in everyday life soon as a source of locomotion. Factoring the simplicity, robustness and resilience to ingress of this design and you have something ideal for pumping heterogeneous fluids like sewerage or fluids with suspended particulate. As a pump, this device has an important role to play in the developing world. This is a good student project.

2008-10-27

433

Six tesla analyzing magnet for heavy-ion beam transport  

SciTech Connect

A superconducting analyzer magnet for particle beam deflection has been designed and is being fabricated for use at the Argonne Tandem-Linac Accelerator System (ATLAS). This six tesla magnet will provide 45/sup 0/ of deflection for the heavy-ion beams from the ATLAS tandem electrostatic accelerator and together with its twin will replace the existing conventional 90/sup 0/ analyzer magnet which will become inadequate when ATLAS is completed.

Smith, R.P.; Bollinger, L.; Erskine, J.; Genens, L.; Hoffman, J.

1980-01-01

434

Improved surface treatment of the superconducting TESLA cavities  

Microsoft Academic Search

The proposed linear electron-positron collider TESLA is based on 1.3 GHz superconducting niobium cavities for particle acceleration. For a centre-of-mass energy of 500 GeV, an accelerating field of 23.4 MV\\/m is required which is reliably achieved with a niobium surface preparation by chemical etching. An upgrade of the collider to 800 GeV requires an improved cavity preparation technique. In this

L. Lilje; C Z Antoine; Cristoforo Benvenuti; D. Bloess; J.-P. Charrier; Enrico Chiaveri; L. Ferreira; R. Losito; A. Matheisen; H. Preis; D. Proch; D. Reschke; H. Safa; P. Schmueser; D. Trines; B. Visentin; Horst Wenninger

2004-01-01

435

Tuning for the first 9-cell TESLA cavity of PKU  

NASA Astrophysics Data System (ADS)

A method based on circuit model is used to tune the first home-made 9-cell TESLA type superconducting niobium cavity at Peking University. After tuning, a flat field profile with a final ?-mode frequency within 3 kHz of target frequency is achieved. The field flatness is measured by a bead-pull method, and the relative electric field is calculated from the frequency shift perturbed by the bead stepping along the axis of the cavity.

Yang, Liu; He, Fei-Si; Xu, Wen-Can; Zhu, Feng; Lu, Xiang-Yang; Zhao, Kui

2010-04-01

436

Next-generation scanner to sub-100-nm lithography  

Microsoft Academic Search

The paper presents the Canon new scanner 6000 platform, incorporated in FPA-6000ES5 KrF scanner and FPA-6000AS4 ArF scanner, realizing both high productivity and high stage controllability for the sub 100nm lithography. We run aerial simulations and estimate process window criteria called CD-window to assess a focus budget and a CD budget meeting the requirement for CD uniformity at the MPU

Itaru Fujita; Fumio M. Sakai; Shigeyuki Uzawa

2003-01-01

437

Optimization of Brain T2 Mapping Using Standard CPMG Sequence In A Clinical Scanner  

NASA Astrophysics Data System (ADS)

In magnetic resonance imaging, transverse relaxation time (T2) mapping is a useful quantitative tool enabling enhanced diagnostics of many brain pathologies. The aim of our study was to test the influence of different sequence parameters on calculated T2 values, including multi-slice measurements, slice position, interslice gap, echo spacing, and pulse duration. Measurements were performed using standard multi-slice multi-echo CPMG imaging sequence on a 1.5 Tesla routine whole body MR scanner. We used multiple phantoms with different agarose concentrations (0 % to 4 %) and verified the results on a healthy volunteer. It appeared that neither the pulse duration, the size of interslice gap nor the slice shift had any impact on the T2. The measurement accuracy was increased with shorter echo spacing. Standard multi-slice multi-echo CPMG protocol with the shortest echo spacing, also the smallest available interslice gap (100 % of slice thickness) and shorter pulse duration was found to be optimal and reliable for calculating T2 maps in the human brain.

Hnilicov, P.; Bittansk, M.; Dobrota, D.

2014-04-01

438

RHQT Nb3Al 15-Tesla magnet design study  

SciTech Connect

Feasibility study of 15-Tesla dipole magnets wound with a new copper stabilized RHQT Nb{sub 3}Al Rutherford cable is presented. A new practical long copper stabilized RHQT Nb{sub 3}Al strand is presented, which is being developed and manufactured at the National Institute of Material Science (NIMS) in Japan. It has achieved a non-copper J{sub c} of 1000A/mm{sup 2} at 15 Tesla at 4.2K, with a copper over non-copper ratio of 1.04, and a filament size less than 50 microns. For this design study a short Rutherford cable with 28 Nb{sub 3}Al strands of 1 mm diameter will be fabricated late this year. The cosine theta magnet cross section is designed using ROXIE, and the stress and strain in the coil is estimated and studied with the characteristics of the Nb{sub 3}Al strand. The advantages and disadvantages of the Nb{sub 3}Al cable are compared with the prevailing Nb{sub 3}Sn cable from the point of view of stress-strain, J{sub c}, and possible degradation of stabilizer due to cabling. The Nb{sub 3}Al coil of the magnet, which will be made by wind and react method, has to be heat treated at 800 degree C for 10 hours. As preparation for the 15 Tesla magnet, a series of tests on strand and Rutherford cables are considered.

Yamada, R.; Ambrosio, G.; Barzi, E.; Kashikin, V.; Kikuchi, A.; Novitski, I.; Takeuchi, T.; Wake, M.; Zlobin, A.; /Fermilab /NIMC, Tsukuba /KEK, Tsukuba

2005-09-01

439

Precision pointing using a dual-wedge scanner  

NASA Technical Reports Server (NTRS)

A system was developed for calibrating and precisely pointing a germanium dual-wedge scanner for a CO2 Doppler lidar from an airborne platform. The equations implemented in pointing the scanner and those in the iterative calibration program, which combines available data with estimated parameters of the scanner orientation relative to the axes of the aircraft's inertial navigation system to arrive at corrected scanner parameters are described. The effect of specific error conditions on program performance and the results of the program when used on 1981 test data are investigated.

Amirault, C. T.; Dimarzio, C. A.

1985-01-01

440

Improved Cerebral Time-of-Flight Magnetic Resonance Angiography at 7 Tesla - Feasibility Study and Preliminary Results Using Optimized Venous Saturation Pulses  

PubMed Central

Purpose Conventional saturation pulses cannot be used for 7 Tesla ultra-high-resolution time-of-flight magnetic resonance angiography (TOF MRA) due to specific absorption rate (SAR) limitations. We overcome these limitations by utilizing low flip angle, variable rate selective excitation (VERSE) algorithm saturation pulses. Material and Methods Twenty-five neurosurgical patients (male n?=?8, female n?=?17; average age 49.64 years; range 2670 years) with different intracranial vascular pathologies were enrolled in this trial. All patients were examined with a 7 Tesla (Magnetom 7 T, Siemens) whole body scanner system utilizing a dedicated 32-channel head coil. For venous saturation pulses a 35 flip angle was applied. Two neuroradiologists evaluated the delineation of arterial vessels in the Circle of Willis, delineation of vascular pathologies, presence of artifacts, vessel-tissue contrast and overall image quality of TOF MRA scans in consensus on a five-point scale. Normalized signal intensities in the confluence of venous sinuses, M1 segment of left middle cerebral artery and adjacent gray matter were measured and vessel-tissue contrasts were calculated. Results Ratings for the majority of patients ranged between good and excellent for most of the evaluated features. Venous saturation was sufficient for all cases with minor artifacts in arteriovenous malformations and arteriovenous fistulas. Quantitative signal intensity measurements showed high vessel-tissue contrast for confluence of venous sinuses, M1 segment of left middle cerebral artery and adjacent gray matter. Conclusion The use of novel low flip angle VERSE algorithm pulses for saturation of venous vessels can overcome SAR limitations in 7 Tesla ultra-high-resolution TOF MRA. Our protocol is suitable for clinical application with excellent image quality for delineation of various intracranial vascular pathologies. PMID:25232868

Wrede, Karsten H.; Johst, Soren; Dammann, Philipp; Ozkan, Neriman; Monninghoff, Christoph; Kraemer, Markus; Maderwald, Stefan; Ladd, Mark E.; Sure, Ulrich; Umutlu, Lale; Schlamann, Marc

2014-01-01

441

Preoperative 3-Tesla Multiparametric Endorectal Magnetic Resonance Imaging Findings and the Odds of Upgrading and Upstaging at Radical Prostatectomy in Men With Clinically Localized Prostate Cancer  

SciTech Connect

Purpose: To investigate whether 3-T esla (3T) multiparametric endorectal MRI (erMRI) can add information to established predictors regarding occult extraprostatic or high-grade prostate cancer (PC) in men with clinically localized PC. Methods and Materials: At a single academic medical center, this retrospective study's cohort included 118 men with clinically localized PC who underwent 3T multiparametric erMRI followed by radical prostatectomy, from 2008 to 2011. Multivariable logistic regression analyses in all men and in 100 with favorable-risk PC addressed whether erMRI evidence of T3 disease was associated with prostatectomy T3 or Gleason score (GS) 8-10 (in patients with biopsy GS {<=}7) PC, adjusting for age, prostate-specific antigen level, clinical T category, biopsy GS, and percent positive biopsies. Results: The accuracy of erMRI prediction of extracapsular extension and seminal vesicle invasion was 75% and 95%, respectively. For all men, erMRI evidence of a T3 lesion versus T2 was associated with an increased odds of having pT3 disease (adjusted odds ratio [AOR] 4.81, 95% confidence interval [CI] 1.36-16.98, P=.015) and pGS 8-10 (AOR 5.56, 95% CI 1.10-28.18, P=.038). In the favorable-risk population, these results were AOR 4.14 (95% CI 1.03-16.56), P=.045 and AOR 7.71 (95% CI 1.36-43.62), P=.021, respectively. Conclusions: Three-Tesla multiparametric erMRI in men with favorable-risk PC provides information beyond that contained in known preoperative predictors about the presence of occult extraprostatic and/or high-grade PC. If validated in additional studies, this information can be used to counsel men planning to undergo radical prostatectomy or radiation therapy about the possible need for adjuvant radiation therapy or the utility of adding hormone therapy, respectively.

Hegde, John V. [Harvard Medical School, Boston, Massachusetts (United States) [Harvard Medical School, Boston, Massachusetts (United States); Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts (United States); Chen, Ming-Hui [Department of Statistics, University of Connecticut, Storrs, Connecticut (United States)] [Department of Statistics, University of Connecticut, Storrs, Connecticut (United States); Mulkern, Robert V. [Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts (United States) [Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts (United States); Department of Radiology, Children's Hospital Boston, Boston, Massachusetts (United States); Fennessy, Fiona M. [Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts (United States) [Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts (United States); Department of Imaging, Dana-Farber Cancer Institute, Boston, Massachusetts (United States); D'Amico, Anthony V. [Department of Radiation Oncology, Brigham and Women's Hospital and Dana-Farber Cancer Institute, Boston, Massachusetts (United States)] [Department of Radiation Oncology, Brigham and Women's Hospital and Dana-Farber Cancer Institute, Boston, Massachusetts (United States); Tempany, Clare M.C., E-mail: ctempany@bwh.harvard.edu [Division of MRI, Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts (United States)

2013-02-01

442

An Investigation of Optimizing and Translating pH-Sensitive Pulsed-Chemical Exchange Saturation Transfer (CEST) Imaging to a 3 T Clinical Scanner  

PubMed Central

Chemical exchange saturation transfer (CEST) MRI provides a sensitive detection mechanism that allows characterization of dilute labile protons usually undetectable by conventional MRI. Particularly, amide proton transfer (APT) imaging, a variant of CEST MRI, has been shown capable of detecting ischemic acidosis, and may serve as a surrogate metabolic imaging marker. For pre-clinical CEST imaging, continuous-wave (CW) RF irradiation is often applied so that the steady state CEST contrast can be reached. On clinical scanners, however, specific absorption rate (SAR) limit and hardware preclude the use of CW irradiation, and instead require an irradiation scheme of repetitive RF pulses (pulsed-CEST imaging). In this work, CW- and pulsed-CEST MRI were systematically compared using a tissue-like pH phantom on an imager capable of both CW and pulsed RF irradiation schemes. The results showed that the maximally obtainable pulsed-CEST contrast is about 95% of CW-CEST contrast, and their optimal RF irradiation powers are equal. Moreover, the pulsed-CEST sequence was translated to a 3 T clinical scanner and detected pH contrast from the labile creatine amine groups (1.9 ppm). Furthermore, pilot endogenous APT imaging of normal human volunteers was demonstrated, warranting future APT MRI of stroke patients to elucidate its diagnostic value. PMID:18816867

Zhe Sun, Phillip; Benner, Thomas; Kumar, Ashok; Sorensen, A Gregory

2008-01-01

443

Multispectral scanner, thematic mapper, and beyond  

NASA Technical Reports Server (NTRS)

The capabilities and functions of the Landsat D multispectral scanner (MSS) and thematic mapper (TM) are explored as a basis for improvements to satisfy increasing user demands. The MSS is an object-space line scanner for gathering data in four spectral bands ranging from 0.5-1.1 micron. In a 705 km near-polar sunsynchronous orbit, the MSS will generate 185 x 185 km imagery with 80 x 80 m ground resolution, mapping the entire earth every 16 days. Photomultiplier tubes are used for four of the bands and the other employs Si photodiodes. A calibration light source provides in orbit calibration during every reverse scan period of a pivotal on-board mirror. The TM collects data in seven bands from 0.45-12.5 microns, yielding a ground resolution of 30 x 30 m in six bands for reflected sunlight and 120 x 120 m for the 10.4-12.5 thermal bands. The addition of 16 Si detectors for 0.9-1.1 micron viewing for agricultural purposes, as well as higher resolution, is discussed.

Jones, C. R.; Engel, J. L.

1981-01-01

444

A 3D airborne ultrasound scanner  

NASA Astrophysics Data System (ADS)

This work investigates the feasibility of an ultrasound scanner designed to reconstruct three-dimensional profiles of objects in air. There are many industrial applications in which it is important to obtain quickly and accurately the digital reconstruction of solid objects with contactless methods. The final aim of this project was the profile reconstruction of shoe lasts in order to eliminate the mechanical tracers from the reproduction process of shoe prototypes. The feasibility of an ultrasonic scanner was investigated in laboratory conditions on wooden test objects with axial symmetry. A bistatic system based on five airborne polyvinylidenedifluoride (PVDF) transducers was mechanically moved to emulate a cylindrical array transducer that can host objects of maximum width and height 20 cm and 40 cm respectively. The object reconstruction was based on a simplified version of the synthetic aperture focusing technique (SAFT): the time of flight (TOF) of the first in time echo for each receiving transducer was taken into account, a coarse spatial sampling of the ultrasonic field reflected on the array transducer was delivered and the reconstruction algorithm was based on the ellipsoidal backprojection. Measurements on a wooden cone section provided submillimetre accuracy in a controlled environment.

Capineri, L.; Masotti, L.; Rocchi, S.

1998-06-01

445

Evaluating scanner lens spherical aberration using scatterometer  

NASA Astrophysics Data System (ADS)

Lens spherical error is an important lens aberration used to characterize lens quality and also has a significant contribution to across chip line width variation (ACLV). It also impacts tool-to-tool matching efforts especially when the optical lithography approaches sub-half wavelength geometry. Traditionally, spherical error is measured by using CD SEM with known drawbacks of poor accuracy and long cycle time. At Texas Instruments, an in-house scatterometer-based lens fingerprinting technique (ScatterLith) performs this tedious job accurately and quickly. This paper presents across slit spherical aberration signatures for ArF scanners collected using this method. The technique can successfully correlate these signatures with Litel lens aberration data and Nikon OCD data for spherical aberration errors as small as 10m?. ACLV contributions from such small spherical errors can be quantified using this method. This provides the lithographer with an important tool to evaluate, qualify and match advanced scanners to improve across chip line width variation control.

Wang, Changan; Zhang, Gary; Tan, Colin L.; Atkinson, Chris; Boehm, Mark A.; Brown, Jay M.; Godfrey, David; Littau, Michael E.; Raymond, Christopher J.

2003-06-01

446

Overall critical current density of chevrel wires in magnetic fields up to 24 tesla  

Microsoft Academic Search

Wires of Pb0.6Sn0.4Mo6S8 with a protective sheet of Niobium have been carefully drawn and the critical current density Jc has been measured on small coils in magnetic fields up to 24 tesla. At 1.9K, the overall JCO, exceeds 100 A\\/mm2 at 20 tesla and 60 A\\/mm2 at 24 tesla. These large values highlight the good sintering between all the grains.

M. Decroux; N. Cheggour; A. Gupta; V. Bouquet; R. Chevrel; J. A. A. J. Perenboom; . Fischer

1996-01-01

447

Timed Efficient Stream Loss-Tolerant Authentication (TESLA): Multicast Source Authentication Transform Introduction  

Microsoft Academic Search

This document introduces Timed Efficient Stream Loss-tolerant Authentication (TESLA). TESLA allows all receivers to check the integrity and authenticate the source of each packet in multicast or broadcast data streams. TESLA requires no trust between receivers, uses low-cost operations per packet at both sender and receiver, can tolerate any level of loss without retransmissions, and requires no per-receiver state at

A. Perrig; R. Canetti; J. D. Tygar; B. Briscoe

2005-01-01

448

Towards MRI-guided linear accelerator control: gating on an MRI accelerator.  

PubMed

To boost the possibilities of image guidance in radiotherapy by providing images with superior soft-tissue contrast during treatment, we pursue diagnostic quality MRI functionality integrated with a linear accelerator. Large respiration-induced semi-periodic target excursions hamper treatment of cancer of the abdominal organs. Methods to compensate in real time for such motion are gating and tracking. These strategies are most effective in cases where anatomic motion can be visualized directly, which supports the use of an integrated MRI accelerator. We establish here an infrastructure needed to realize gated radiation delivery based on MR feedback and demonstrate its potential as a first step towards more advanced image guidance techniques. The position of a phantom subjected to one-dimensional periodic translation is tracked with the MR scanner. Real-time communication with the MR scanner and control of the radiation beam are established. Based on the time-resolved position of the phantom, gated radiation delivery to the phantom is realized. Dose distributions for dynamic delivery conditions with varying gating windows are recorded on gafchromic film. The similarity between dynamically and statically obtained dose profiles gradually increases as the gating window is decreased. With gating windows of 5 mm, we obtain sharp dose profiles. We validate our gating implementation by comparing measured dose profiles to theoretical profiles calculated using the knowledge of the imposed motion pattern. Excellent correspondence is observed. At the same time, we show that real-time on-line reconstruction of the accumulated dose can be performed using time-resolved target position information. This facilitates plan adaptation not only on a fraction-to-fraction scale but also during one fraction, which is especially valuable in highly accelerated treatment strategies. With the currently established framework and upcoming improvements to our prototype-integrated MRI accelerator, we will realize more intricate MRI-guided linear accelerator control in the near future. PMID:21753236

Crijns, S P M; Kok, J G M; Lagendijk, J J W; Raaymakers, B W

2011-08-01

449

Design and Preliminary Accuracy Studies of an MRI-Guided Transrectal Prostate Intervention System  

PubMed Central

This paper reports a novel system for magnetic resonance imaging (MRI) guided transrectal prostate interventions, such as needle biopsy, fiducial marker placement, and therapy delivery. The system utilizes a hybrid tracking method, comprised of passive fiducial tracking for initial registration and subsequent incremental motion measurement along the degrees of freedom using fiber-optical encoders and mechanical scales. Targeting accuracy of the system is evaluated in prostate phantom experiments. Achieved targeting accuracy and procedure times were found to compare favorably with existing systems using passive and active tracking methods. Moreover, the portable design of the system using only standard MRI image sequences and minimal custom scanner interfacing allows the system to be easily used on different MRI scanners. PMID:18044553

Krieger, Axel; Csoma, Csaba; Iordachita, Iulian I.; Guion, Peter; Singh, Anurag K.; Fichtinger, Gabor; Whitcomb, Louis L.

2012-01-01

450

TESLA FEL Report 200602 Finite Element Analyses for RF Photoinjector Gun Cavities  

E-print Network

TESLA FEL Report 200602 Finite Element Analyses for RF Photoinjector Gun ..............................................................................................................................................................19 3.1. DESY GUN 2..................................................................................................................................................19 3.2. DESY GUN 4

451

Towards a Hall effect magnetic tracking device for MRI.  

PubMed

This paper presents the first prototype of a magnetic tracking device for Magnetic Resonance Imaging. The unique relationship between the space coordinates of a MRI scanner bore and the magnetic field gradients used in MRI allows building a localization system based on an accurate measurement of these gradients. These gradients are measured thanks to a 3D Hall device with a footprint of only 50m(2), integrated with its specific conditioning circuit in a low cost, low voltage 0.35m CMOS process. The first experimental results show that a sub-millimeter localization is possible. It opens the way to the development of MRI compatible magnetic tracking systems integrable in a surgical tool. PMID:24110349

Schell, J-B; Kammerer, J-B; Hbrard, L; Breton, E; Gounot, D; Cuvillon, L; de Mathelin, M

2013-01-01

452

Characterization of Flexible RF Microcoil Dedicated to Surface Mri  

E-print Network

In Magnetic Resonance Imaging (MRI), to achieve sufficient Signal to Noise Ratio (SNR), the electrical performance of the RF coil is critical. We developed a device (microcoil) based on the original concept of monolithic resonator. This paper presents the used fabrication process based on micromoulding. The dielectric substrates are flexible thin films of polymer, which allow the microcoil to be form fitted to none-plane surface. Electrical characterizations of the RF coils are first performed and results are compared to the attempted values. Proton MRI of a saline phantom using a flexible RF coil of 15 mm in diameter is performed. When the coil is conformed to the phantom surface, a SNR gain up to 2 is achieved as compared to identical but planar RF coil. Finally, the flexible coil is used in vivo to perform MRI with high spatial resolution on a mouse using a small animal dedicated scanner operating at in a 2.35 T.

Woytasik, M; Raynaud, J -S; Poirier-Quinot, M; Dufour-Gergam, E; Grandchamp, J -P; Darrasse, L; Robert, P; Gilles, J -P; Martincic, E; Girard, O

2007-01-01

453

A paint-brush laser range scanner Lyubomir Zagorchev and A. Ardeshir Goshtasby  

E-print Network

A paint-brush laser range scanner Lyubomir Zagorchev and A. Ardeshir Goshtasby Computer Science and Engineering Department, Wright State University, Dayton, OH 45435 Abstract A new hand-held laser range scanner are presented. Keywords: Laser range scanner; 3-D scanner; Hand-held scanner; Object-centered scanning; image

Goshtasby, Arthur Ardeshir

454

Scanner OPC signatures: automatic vendor-to-vendor OPE matching  

NASA Astrophysics Data System (ADS)

As 193nm lithography continues to be stretched and the k1 factor decreases, optical proximity correction (OPC) has become a vital part of the lithographer's tool kit. Unfortunately, as is now well known, the design variations of lithographic scanners from different vendors cause them to have slightly different optical-proximity effect (OPE) behavior, meaning that they print features through pitch in distinct ways. This in turn means that their response to OPC is not the same, and that an OPC solution designed for a scanner from Company 1 may or may not work properly on a scanner from Company 2. Since OPC is not inexpensive, that causes trouble for chipmakers using more than one brand of scanner. Clearly a scanner-matching procedure is needed to meet this challenge. Previously, automatic matching has only been reported for scanners of different tool generations from the same manufacturer. In contrast, scanners from different companies have been matched using expert tuning and adjustment techniques, frequently requiring laborious test exposures. Automatic matching between scanners from Company 1 and Company 2 has remained an unsettled problem. We have recently solved this problem and introduce a novel method to perform the automatic matching. The success in meeting this challenge required three enabling factors. First, we recognized the strongest drivers of OPE mismatch and are thereby able to reduce the information needed about a tool from another supplier to that information readily available from all modern scanners. Second, we developed a means of reliably identifying the scanners' optical signatures, minimizing dependence on process parameters that can cloud the issue. Third, we carefully employed standard statistical techniques, checking for robustness of the algorithms used and maximizing efficiency. The result is an automatic software system that can predict an OPC matching solution for scanners from different suppliers without requiring expert intervention.

Renwick, Stephen P.

2009-03-01

455

Clinical applications of PET/MRI: current status and future perspectives.  

PubMed

Fully integrated positron emission tomography (PET)/magnetic resonance imaging (MRI) scanners have been available for a few years. Since then, the number of scanner installations and published studies have been growing. While feasibility of integrated PET/MRI has been demonstrated for many clinical and preclinical imaging applications, now those applications where PET/MRI provides a clear benefit in comparison to the established reference standards need to be identified. The current data show that those particular applications demanding multiparametric imaging capabilities, high soft tissue contrast and/or lower radiation dose seem to benefit from this novel hybrid modality. Promising results have been obtained in whole-body cancer staging in non-small cell lung cancer and multiparametric tumor imaging. Furthermore, integrated PET/MRI appears to have added value in oncologic applications requiring high soft tissue contrast such as assessment of liver metastases of neuroendocrine tumors or prostate cancer imaging. Potential benefit of integrated PET/MRI has also been demonstrated for cardiac (i.e., myocardial viability, cardiac sarcoidosis) and brain (i.e., glioma grading, Alzheimer's disease) imaging, where MRI is the predominant modality. The lower radiation dose compared to PET/computed tomography will be particularly valuable in the imaging of young patients with potentially curable diseases.However, further clinical studies and technical innovation on scanner hard- and software are needed. Also, agreements on adequate refunding of PET/MRI examinations need to be reached. Finally, the translation of new PET tracers from preclinical evaluation into clinical applications is expected to foster the entire field of hybrid PET imaging, including PET/MRI. PMID:25010371

Nensa, Felix; Beiderwellen, Karsten; Heusch, Philipp; Wetter, Axel

2014-01-01

456

Magnetic-field-induced dose effects in MR-guided radiotherapy systems: dependence on the magnetic field strength  

Microsoft Academic Search

Several institutes are currently working on the development of a radiotherapy treatment system with online MR imaging (MRI) modality. The main difference between their designs is the magnetic field strength of the MRI system. While we have chosen a 1.5 Tesla (T) magnetic field strength, the Cross Cancer Institute in Edmonton will be using a 0.2 T MRI scanner and

A. J. E. Raaijmakers; B. W. Raaymakers; J. J. W. Lagendijk

2008-01-01

457

Dynamic contrast MRI  

Cancer.gov

Recommendations for MR measurement methods at 1.5-Tesla and endpoints for use in Phase 1/2a trials of anti-cancer therapeutics affecting tumor vascular function Type of measurement Study design should incorporate quality assurance of the MR system,

458

3 Tesla MR neurography--technique, interpretation, and pitfalls.  

PubMed

MRI has been used for almost two decades for the evaluation of peripheral nerve disorders. This article highlights the relative advantages and disadvantages of 3T MR neurography in the evaluation of peripheral neuropathies. The authors also describe the high-resolution MR neurography technique on 3T MRI, along with the approach to its interpretation that has evolved at one institution. PMID:21547613

Chhabra, Avneesh; Lee, Pearlene P; Bizzell, Cary; Soldatos, Theodoros

2011-10-01

459

Structural MRI scan Functional MRI scan  

E-print Network

FUNCTIONAL IMAGING LABORATORY www.fil.ion.ucl.ac.uk MRI INFORMATION #12;MRI is short for Magnetic Resonance. For the same reason, people with certain metallic implants cannot be scanned. Such metal items include any of the following: Cardiac pacemakers, cochlear implants, metallic aneurysm clips, metallic fragments in the eye

Zeki, Semir

460

MRI-guided nanorobotic systems for therapeutic and diagnostic applications.  

PubMed

This review presents the state of the art of magnetic resonance imaging (MRI)-guided nanorobotic systems that can perform diagnostic, curative, and reconstructive treatments in the human body at the cellular and subcellular levels in a controllable manner. The concept of an MRI-guided nanorobotic system is based on the use of an MRI scanner to induce the required external driving forces to propel magnetic nanocapsules to a specific target. It is an active targeting mechanism that provides simultaneous propulsion and imaging capabilities, which allow the implementation of real-time feedback control of the targeting process. The architecture of the system comprises four main modules: (a) the nanocapsules, (b) the MRI propulsion module, (c) the MRI tracking module (for image processing), and (d) the controller module. A key concept is the nanocapsule technology, which is based on carriers such as liposomes, polymer micelles, gold nanoparticles, quantum dots, metallic nanoshells, and carbon nanotubes. Descriptions of the significant challenges faced by the MRI-guided nanorobotic system are presented, and promising solutions proposed by the involved research community are discussed. Emphasis is placed on reviewing the limitations imposed by the scaling effects that dominate within the blood vessels and also on reviewing the control algorithms and computational tools that have been developed for real-time propulsion and tracking of the nanocapsules. PMID:21529162

Vartholomeos, Panagiotis; Fruchard, Matthieu; Ferreira, Antoine; Mavroidis, Constantinos

2011-08-15

461

19. SITE BUILDING 002 SCANNER BUILDING AIR POLICE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

19. SITE BUILDING 002 - SCANNER BUILDING - AIR POLICE SITE SECURITY OFFICE WITH "SITE PERIMETER STATUS PANEL" AND REAL TIME VIDEO DISPLAY OUTPUT FROM VIDEO CAMERA SYSTEM AT SECURITY FENCE LOCATIONS. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

462

26. SITE BUILDING 002 SCANNER BUILDING OPERATIONS CENTER ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

26. SITE BUILDING 002 - SCANNER BUILDING - OPERATIONS CENTER - MWOC IN OPERATION AT 1945 ZULU TIME, 26 OCTOBER, 1999. "SPACE TRACK BOARD" DATA SHOWING ITEMS #16609 MIR (RUSSIA) AND #25544 ISS (INTERNATIONAL SPACE STATION) BEING TRACKED. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

463

29. SITE BUILDING 002 SCANNER BUILDING FLOOR 3A ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

29. SITE BUILDING 002 - SCANNER BUILDING - FLOOR 3A ("A" FACE) AT SYSTEM LAYOUT GRID 17. GENERAL OBLIQUE VIEW OF "A" FACE INTERIOR SHOWING RADAR EMITTER/ANTENNA INTERFACE ELECTRONICS. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

464

ONE-SHOT RANGE SCANNER USING COPLANARITY CONSTRAINTS Ryo Furukawa,  

E-print Network

or faces with dynamic expres- sions, 3D scanners using high-speed structured light systems have been using structured light have been proposed. Many of these systems use either mul- tiple patterns scanners are widely used for actual 3D model acquisition process [1]. Especially, structured light based

Tokyo, University of

465

Laser excited confocal microscope fluorescence scanner and method  

DOEpatents

A fluorescent scanner is designed for scanning the fluorescence from a fluorescence labeled separated sample on a sample carrier. The scanner includes a confocal microscope for illuminating a predetermined volume of the sample carrier and/or receiving and processing fluorescence emissions from the volume to provide a display of the separated sample. 8 figs.

Mathies, R.A.; Peck, K.

1992-02-25

466

21. SITE BUILDING 002 SCANNER BUILDING LOOKING AT ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

21. SITE BUILDING 002 - SCANNER BUILDING - LOOKING AT DISC STORAGE SYSTEMS A AND B (A OR B ARE REDUNDANT SYSTEMS), ONE MAINFRAME COMPUTER ON LINE, ONE ON STANDBY WITH STORAGE TAPE, ONE ON STANDBY WITHOUT TAPE INSTALLED. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA