scholarly journals Hexagonal zero mode TEM coil: A single-channel coil design for imaging multiple small animals

2005 ◽  
Vol 53 (5) ◽  
pp. 1150-1157 ◽  
Author(s):  
Jelena Lazovic ◽  
Dragan S. Stojkovic ◽  
Christopher M. Collins ◽  
Qing X. Yang ◽  
J. Thomas Vaughan ◽  
...  
Author(s):  
Byungmok Kim ◽  
Yongmin Chang ◽  
Hea Jung Choi ◽  
Ki-Su Park ◽  
Ji-ung Yang ◽  
...  

<b><i>Background:</i></b> The usage of multichannel brain MRI coils, which have several advantages over single-channel brain coils used for stereotactic radiosurgery (SRS), requires a frame adapter device to fit the frames inside the multichannel brain coils. However, such a frame adapter has not been developed until now. <b><i>Objective:</i></b> to develop an SRS frame adapter for multichannel MRI coils and verify the geometrical accuracy and signal-to-noise ratio (SNR) of the MR images obtained using multichannel MRI coils. <b><i>Methods:</i></b> We fabricated an SRS frame adapter for a 48-channel MRI coil using a three-dimensional (3D) printer. Furthermore, we obtained phantom and human-brain MR images with a 3.0 Tesla MRI scanner using multi- and single-channel coils. Computed tomography (CT) phantom images were also obtained as reference. We compared the coordinate errors of the multi- and single-channel coils to evaluate the geometrical accuracy. Two neurosurgeons measured the coordinates. In addition, we compared the SNR differences between multi- and single-channel coils using the T1- and T2-weighted brain images. <b><i>Results:</i></b> For the CT coordinate measurements, the correlation coefficient <i>r</i> = 1 and <i>p</i> &#x3c; 0.001 with respect to the 3 axes (Δ<i>x</i>, Δ<i>y</i>, and Δ<i>z</i>) and 3D errors (Δ<i>r</i>) showed no interpersonal differences between the 2 neurosurgeons. The results obtained using the T1-weighted images showed that a multichannel coil had smaller coordinate errors in Δ<i>x</i>, Δ<i>y</i>, Δ<i>z</i>, and Δ<i>r</i> than that observed in case of a single-channel coil (<i>p</i> &#x3c; 0.001). In case of the SNR measurements, most of the brain areas showed higher SNRs when using a multichannel coil compared with that observed when using a single-channel coil in the T1- and T2-weighted images. <b><i>Conclusion:</i></b> Compared with single-channel coils, the use of multichannel MRI coils with a newly developed frame adapter is expected to ensure successful SRS treatments with improved geometrical accuracy and SNR.


2021 ◽  
Vol 2015 (1) ◽  
pp. 012171
Author(s):  
V Puchnin ◽  
V Ivanov ◽  
M Gulyaev ◽  
M Zubkov

Abstract We present the initial experimental results obtained using a two-part receive/transmit (Rx/Tx) radiofrequency (RF) coil design for small animals magnetic resonance imaging at 7 T. The assembly uses a butterfly-type coil tuned to 300 MHz for scanning the 1H nuclei and a non-resonant antenna with a metamaterial-inspired resonator tunable over wide frequency range for X-nuclei. 1H, 31P, 23Na and 13C are selected as test nuclei in this work. Coil simulations show the two parts of the RF-assembly to be efficiently operating at the required frequencies. Simulations and phantom imaging show sufficiently homogeneous transverse transmit RF fields and tuning capabilities for the pilot heteronuclear experiments.


Author(s):  
P. Trebbia ◽  
P. Ballongue ◽  
C. Colliex

An effective use of electron energy loss spectroscopy for chemical characterization of selected areas in the electron microscope can only be achieved with the development of quantitative measurements capabilities.The experimental assembly, which is sketched in Fig.l, has therefore been carried out. It comprises four main elements.The analytical transmission electron microscope is a conventional microscope fitted with a Castaing and Henry dispersive unit (magnetic prism and electrostatic mirror). Recent modifications include the improvement of the vacuum in the specimen chamber (below 10-6 torr) and the adaptation of a new electrostatic mirror.The detection system, similar to the one described by Hermann et al (1), is located in a separate chamber below the fluorescent screen which visualizes the energy loss spectrum. Variable apertures select the electrons, which have lost an energy AE within an energy window smaller than 1 eV, in front of a surface barrier solid state detector RTC BPY 52 100 S.Q. The saw tooth signal delivered by a charge sensitive preamplifier (decay time of 5.10-5 S) is amplified, shaped into a gaussian profile through an active filter and counted by a single channel analyser.


1968 ◽  
Vol 11 (1) ◽  
pp. 189-193 ◽  
Author(s):  
Lois Joan Sanders

A tongue pressure unit for measurement of lingual strength and patterns of tongue pressure is described. It consists of a force displacement transducer, a single channel, direct writing recording system, and a specially designed tongue pressure disk, head stabilizer, and pressure unit holder. Calibration with known weights indicated an essentially linear and consistent response. An evaluation of subject reliability in which 17 young adults were tested on two occasions revealed no significant difference in maximum pressure exerted during the two test trials. Suggestions for clinical and research use of the instrumentation are noted.


Nature ◽  
2006 ◽  
Author(s):  
Philip Ball
Keyword(s):  

1884 ◽  
Vol 17 (430supp) ◽  
pp. 6869-6870
Author(s):  
W. N. Lockington
Keyword(s):  

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