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Result : Searchterm 'Shimming' found in 3 terms [] and 76 definitions []
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Searchterm 'Shimming' was also found in the following services: 
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News  (1)  Resources  (2)  Forum  (9)  
 
ShimmingForum -
related threads
 
Correction of inhomogeneity of the magnetic field produced by the main magnet of a MRI system due to imperfections in the magnet or to the presence of external ferromagnetic objects. May involve changing the configuration of the magnet or the using of shim coils (active shimming) or adding or removing steel from the magnets poles (passive shimming) to fine-tune the magnetic field.

See also the related poll result: 'Most outages of your scanning system are caused by failure of'
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• Related Searches:
    • Homogeneity
    • MRI Equipment
    • Balanced Sequence
    • Coil
    • Magnetic Resonance Spectroscopy
 
Further Reading:
  News & More:
Implementation of Dual-Source RF Excitation in 3 T MR-Scanners Allows for Nearly Identical ADC Values Compared to 1.5 T MR Scanners in the Abdomen
Wednesday, 29 February 2012   by www.plosone.org    
MRI Resources 
MRCP - MRI Centers - Implant and Prosthesis pool - Raman Spectroscopy - Shielding - Pacemaker
 
Active Shimming
 
Shimming by suitably adjusting the currents in shim coils for qualitiy assurance.
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• View the DATABASE results for 'Active Shimming' (4).Open this link in a new window

 
Further Reading:
  Basics:
Second Order Shimming of High Field Magnets
   by www.healthcare.siemens.com    
  News & More:
Improved shim method based on the minimization of the maximum off-resonance frequency for balanced SSFP
Monday, 1 June 2009   by www.ncbi.nlm.nih.gov    
MRI Resources 
Spine MRI - Implant and Prosthesis - MRI Physics - Movies - Most Wanted - Abdominal Imaging
 
Passive Shimming
 
Shimming by adjusting the position of suitable pieces of ferromagnetic metal within or around the main magnet of a MRI system. Typically, the iron is in the form of small plates which are held in removable trays. The magnetic field is plotted, the position and quality of the iron required is then calculated and the appropriate 'shims' put in place. Several repetitions of this process will normally be required in order to achieve the optimum arrangement.
Passive shimming does not replace adjustable shimming, but is installed during the commissioning of a unit to improve the homogeneity of the bare magnet.
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• View the DATABASE results for 'Passive Shimming' (4).Open this link in a new window

Searchterm 'Shimming' was also found in the following services: 
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News  (1)  Resources  (2)  Forum  (9)  
 
Altaire™InfoSheet: - Devices -
Intro, 
Types of Magnets, 
Overview, 
etc.MRI Resource Directory:
 - Devices -
 
www.hitachimed.com/products/altaire.asp From Hitachi Medical Systems America, Inc.;
the AIRIS made its debut in 1995. Hitachi followed up with the AIRIS II system, which has proven equally successfully. 'All told, Hitachi has installed more than 1,000 MRI systems in the U.S., holding more than 17 percent of the total U.S. MRI installed base, and more than half of the installed base of open MR systems,' says Antonio Garcia, Frost and Sullivan industry research analyst. Now Altaire employs a blend of innovative Hitachi features called VOSI™ technology, optimizing each sub-system's performance in concert with the other sub-systems, to give the seamless mix of high-field performance and the patient comfort, especially for claustrophobic patients, of open MR systems.

Device Information and Specification
CLINICAL APPLICATION
Whole body
CONFIGURATION
Vertical Field, Open MRI
DualQuad T/R Body Coil, MA Head, MA C-Spine, MA Shoulder, MA Wrist, MA CTL Spine, MA Knee, MA TMJ, MA Flex Body (3 sizes), Neck, small and large Extremity, PVA (WIP), Breast (WIP), Neurovascular (WIP), Cardiac (WIP) and MA Foot//Ankle (WIP)
SYNCHRONIZATION
Cardiac gating, ECG/peripheral, respiratory gating (2 modes)
PULSE SEQUENCES
SE, GE, GR, IR, FIR, STIR, ss-FSE, FSE, DE-FSE/FIR, FLAIR, ss/ms-EPI, ss/ms EPI- DWI, SSP, MTC, SE/GE-EPI, MRCP, SARGE, RSSG, TRSG, BASG, Angiography: CE, PC, 2D/3D TOF
IMAGING MODES
Single, multislice, volume study
TR
SE: 30 - 10,000msec GE: 3.6 - 10,000msec IR: 50 - 16,700msec FSE: 200 - 16,7000msec
TE
SE : 8 - 250msec IR: 5.2 -7,680msec GE: 1.8 - 2,000 msec FSE: 5.2 - 7,680
SINGLE/MULTI SLICE
0.05 sec/image (256 x 256)
FOV
5cm to 45 cm continuous
2D: 2 - 100 mm; 3D: 0.5 - 5 mm
1280 x 1024
MEASURING MATRIX
512 x 512
PIXEL INTENSITY
Level Range: -2,000 to +4,000
Sub millimeter
MAGNET TYPE
Self-shielded, superconducting
BORE DIAMETER
or W x H
110 x 43 cm
MAGNET WEIGHT
41,700 kg
H*W*D
256 x 348 x 236 cm
POWER REQUIREMENTS
208 V +/- 10%, 3 phase
COOLING SYSTEM TYPE
Water-cooled
STRENGTH
22 mT/m
3.1 m lateral, 3.6 m vertical
Auto shimming, 3-axis/patient and active shimming
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• View the DATABASE results for 'Altaire™' (2).Open this link in a new window

 
Further Reading:
  News & More:
Altaire High-Field Open MRI(.pdf)
2001
MRI Resources 
Contrast Agents - Journals - Spectroscopy - Universities - Pathology - Chemistry
 
MRP-7000™InfoSheet: - Devices -
Intro, 
Types of Magnets, 
Overview, 
etc.MRI Resource Directory:
 - Devices -
 
www.hitachimed.com/products/mrp.asp From Hitachi Medical Systems America, Inc.;
because of its dependability, the MRP-7000™ remains popular more than a decade after the first U.S. system was shipped. This system maintains a high resale value, what has made it one of the most sought-after scanners on the used MRI equipment market.
Device Information and Specification
CLINICAL APPLICATION
Whole body
CONFIGURATION
Vertical Orientation Field
DualQuad T/R Body Coil, MA Head, MA C-Spine, MA Shoulder, MA Wrist, MA CTL Spine, MA Knee, MA TMJ, MA Flex Body (3 sizes), Neck, small and large Extremity, PVA (WIP), Breast (WIP), Neurovascular (WIP), Cardiac (WIP) and MA Foot//Ankle (WIP)
SYNCHRONIZATION
Cardiac gating, ECG/peripheral, respiratory gating (2 modes)
PULSE SEQUENCES
SE, GE, GR, IR, FIR, STIR, ss-FSE, FSE, DE-FSE/FIR, FLAIR, ss/ms-EPI, ss/ms EPI- DWI, SSP, MTC, SE/GE-EPI, MRCP, SARGE, RSSG, TRSG, BASG, Angiography: CE, PC, 2D/3D TOF
IMAGING MODES
Single, multislice, volume study
MAGNET TYPE
Permanent, self shielded
STRENGTH
8 mT/m
5-GAUSS FRINGE FIELD
horizontal 2.5 m x 2.1 m vertical
Auto shimming, 3-axis/patient and active shimming
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• View the DATABASE results for 'MRP-7000™' (2).Open this link in a new window

MRI Resources 
RIS - Shielding - Shoulder MRI - Colonography - Collections - Jobs pool
 
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