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Result : Searchterm 'Shielding' found in 8 terms [] and 18 definitions []
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Searchterm 'Shielding' was also found in the following services: 
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News  (2)  Resources  (5)  Forum  (1)  
 
C-SCAN™InfoSheet: - Devices -
Intro, 
Types of Magnets, 
Overview, 
etc.MRI Resource Directory:
 - Devices -
 
www.gehealthcare.com/usen/mr/cscan/index.html Manufactured by Esaote S.p.A.; compact in-office MRI system, fits in a 90 ft2 (8.4 m2) space and requires no shielding or special power. This low field MRI magnet is optimized for orthopedic use and imaging of the extremities.
The C-SCAN™ is developed from the ARTOSCAN™ - M with a new computer platform, and is also known as Artoscan C.
Esaote North America and Hologic Inc. are the U.S. distributors of this MRI device.
Device Information and Specification
CLINICAL APPLICATION
Dedicated extremity
CONFIGURATION
Closed
Linear and dual phased array, knee, ankle, wrist (6 total) coils
PULSE SEQUENCES
SE, GE, IR, STIR, FSE, 3D CE, GE-STIR, 3D GE, ME, TME, HSE
IMAGING MODES
Single, multislice, volume study, fast scan, multi slab
TR
12 - 5,000 msec
TE
5 - 220 msec
SINGLE SLICE
0.8 sec/image
MULTISLICE
0.8 sec/image
FOV
10 - 20 cm
2D: 2 mm - 10 mm;
3D: 0.6 mm - 10 mm
512 x 512
MEASURING MATRIX
256 x 256 maximum
PIXEL INTENSITY
4,096 gray lvls, 256 lvls in 3D
MAGNET TYPE
Permanent
BORE DIAMETER
or W x H
33.6 x 16 cm
MAGNET WEIGHT
960 kg
H*W*D
124 x 76 x 60 cm
POWER REQUIREMENTS
100/110/200/220/230/240
STRENGTH
10 mT/m
5-GAUSS FRINGE FIELD, radial/axial
28 cm/60 cm
Passive
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Radiology  (10) Open this link in a new window
Chemical Shift ArtifactInfoSheet: - Artifacts - 
Case Studies, 
Reduction Index, 
etc.MRI Resource Directory:
 - Artifacts -
 
Quick Overview
Please note that there are different common names for this artifact.
Artifact Information
NAME
Chemical shift, black boundary, spatial misregistration, relief
DESCRIPTION
Black or bright band
During frequency encoding, fat protons precess slower than water protons in the same slice because of their magnetic shielding. Through the difference in resonance frequency between water and fat, protons at the same location are misregistrated (dislocated) by the Fourier transformation, when converting MRI signals from frequency to spatial domain. This chemical shift misregistration cause accentuation of any fat-water interfaces along the frequency axis and may be mistaken for pathology. Where fat and water are in the same location, this artifact can be seen as a bright or dark band at the edge of the anatomy.
Protons in fat and water molecules are separated by a chemical shift of about 3.5 ppm. The actual shift in Hertz (Hz) depends on the magnetic field strength of the magnet being used. Higher field strength increases the misregistration, while in contrast a higher gradient strength has a positive effect. For a 0.3 T system operating at 12.8 MHz the shift will be 44.8 Hz compared with a 223.6 Hz shift for a 1.5 T system operating at 63.9 MHz.
mri safety guidance
Image Guidance
For artifact reduction helps a smaller water fat shift (higher bandwidth), a higher matrix, an in phase TE or a spin echo technique. Since the misregistration offset is present in the read out axis the patient may be rescanned with this axis parallel to the fat-water interface. Steeper gradient may be employed to reduce the chemical shift offset in mm. Another strategy is to employ specialized pulse sequences such as fat saturation or inversion recovery imaging. Fat suppression techniques eliminate chemical shift artifacts caused by the lack of fat signal.

See also Black Boundary Artifact and Magnetic Resonance Spectroscopy.
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• View the DATABASE results for 'Chemical Shift Artifact' (7).Open this link in a new window

 
Further Reading:
  Basics:
MRI Artifact Gallery
   by chickscope.beckman.uiuc.edu    
  News & More:
What is chemical shift artefact? Why does it occur? How many Hz at 1.5 T?
   by www.revisemri.com    
Abdominal MRI at 3.0 T: The Basics Revisited
Wednesday, 20 July 2005   by www.ajronline.org    
MRI Resources 
Safety Products - MRI Technician and Technologist Career - Online Books - Universities - Education - Hospitals
 
Cryostat
 
Cryostats are devices for maintaining a constant low temperature (as by means of liquid helium used in MRI). They require vacuum chambers with thermal isolation.

See also Dewar, Cryoshielding and Boil off Rate.
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• View the DATABASE results for 'Cryostat' (6).Open this link in a new window

 
Further Reading:
  Basics:
Superconducting Magnets
   by mri-q.com    
Zero Boil Off Cryostats
Friday, 23 September 2011   by www.cryogenicsociety.or    
Searchterm 'Shielding' was also found in the following services: 
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News  (2)  Resources  (5)  Forum  (1)  
 
Eddy Current ArtifactInfoSheet: - Artifacts - 
Case Studies, 
Reduction Index, 
etc.
 
Quick Overview
Artifact Information
NAME
Eddy current
DESCRIPTION
Image distortion
REASON
Induced by changes in a magnetic field
Eddy currents can cause artifacts in images and may seriously degrade overall magnet performance.
mri safety guidance
Image Guidance
Common uses to reduce the influence of eddy currents on gradient fields are eddy current compensation and shielded gradient coils (active or passive). If persistent, it must be addressed by a service representative to verify the magnet performance.

See also Eddy Current Compensation.
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• View the DATABASE results for 'Eddy Current Artifact' (2).Open this link in a new window

 
Further Reading:
  Basics:
Generic Eddy Current Compensation for Rapid Magnetic Resonance Imaging(.pdf)
   by www.switt.ch    
Searchterm 'Shielding' was also found in the following service: 
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Radiology  (10) Open this link in a new window
MRI EquipmentInfoSheet: - Devices -
Intro, 
Types of Magnets, 
Overview, 
etc.
 
The MRI equipment consists of following components:
The magnet generates the magnetic field.
Shim coils make the magnetic field homogeneous.
Radio frequency coils transmit the radio signal into the body part being imaged.
Receiver coils detect the returning radio signals.
Gradient coils provide spatial localization of the signals.
Shielding coils produce a magnetic field that cancels the field from primary coils in regions where it is not desired.
The computer reconstructs the signals into the image.
The MRI scanner room is shielded by a faraday shield.
Different cooling systems cool the magnet, the scanner room and the technique room.

Better MRI equipment and software design along with the latest information technology improves system maintenance and overall communication. Software and digital imaging and communications in medicine (DICOM) compatibility allows to network into hospital databases, helps to modify pulse sequences, data post processing, and archiving via picture archiving and communication system (PACS).

See also the related poll result: 'Most outages of your scanning system are caused by failure of'
Radiology-tip.comradCT Scanner,  Radiography
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Medical-Ultrasound-Imaging.comUltrasound Machine,  Ultrasound System Performance
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• View the DATABASE results for 'MRI Equipment' (13).Open this link in a new window


• View the NEWS results for 'MRI Equipment' (4).Open this link in a new window.
 
Further Reading:
  News & More:
Low Power MRI Helps Image Lungs, Brings Costs Down
Thursday, 10 October 2019   by www.medgadget.com    
MRI safety targeted as new group offers credentialing test
Monday, 12 January 2015   by www.modernhealthcare.com    
Audio/Video System helps patients relax during MRI scans
Monday, 8 December 2014   by news.thomasnet.com    
Dräger introduces anaesthesia system for MRI environment
Wednesday, 12 December 2007   by www.mtbeurope.info    
MRI Resources 
Safety Training - MRI Accidents - Intraoperative MRI - Shoulder MRI - Brain MRI - Mass Spectrometry
 
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