Magnetic Resonance - Technology Information Portal Welcome to MRI Technology••
Info
  Sheets


Out-
      side
 



 
 'Ferromagnetism' 
SEARCH FOR    
 
  2 3 5 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Result : Searchterm 'Ferromagnetism' found in 1 term [] and 6 definitions []
1 - 5 (of 7)     next
Result Pages : [1]  [2]
MRI Resources 
Implant and Prosthesis - RIS - MRI Training Courses - Research Labs - Liver Imaging - Functional MRI
 
Ferromagnetism
 
Ferromagnetism is a phenomenon by which a material can exhibit a spontaneous magnetization: a net magnetic moment in the absence of an external magnetic field. More recently: a material is ferromagnetic, only if all of its magnetic ions add a positive contribution to the net magnetization (for differentiation to ferrimagnetic and antiferromagnetic materials). If some of the magnetic ions subtract from the net magnetization (if they are partially anti-aligned), then the material is ferrimagnetic. If the ions anti-align completely so as to have zero net magnetization, despite the magnetic ordering, then it is an antiferromagnet. All of these alignment effects only occur at temperatures below a certain critical temperature, called the Curie temperature (for ferromagnets and ferrimagnets) or the Néel temperature (for antiferromagnets). Typical ferromagnetic materials are iron, cobalt, and nickel.
In MRI ferromagnetic objects, even very small ones, as implants or incorporations distort the homogeneity of the main magnetic field and cause susceptibility artifacts.
spacer
 
• Share the entry 'Ferromagnetism':  Facebook  Twitter  LinkedIn  
 
Further Reading:
  Basics:
Magnet basics
   by my.execpc.com    
Ferromagnetism
   by en.wikipedia.org    
  News & More:
Superconducting Magnets
   by hyperphysics.phy-astr.gsu.edu    
MRI Resources 
Hospitals - Developers - Libraries - Software - Bioinformatics - Breast Implant
 
Ferromagnetic Contrast AgentsInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.MRI Resource Directory:
 - Contrast Agents -
 
A contrast agent, which due to their ferromagnetism produce local field inhomogeneities and hence visible image alterations in the tissues where they are present. Therefore, they can act as contrast media. Usually, particles exhibiting superparamagnetism rather than ferromagnetism are used.

See also the related poll result: 'The development of contrast agents in MRI is'
spacer
MRI Resources 
Examinations - Knee MRI - General - MRCP - Chemistry - Portals
 
Diamagnetism
 
Diamagnetism is a form of magnetism that is only exhibited by a substance in the presence of an externally applied magnetic field. It is the result of changes in the orbital motion of electrons due to the application of an externally applied magnetic field. Applying a magnetic field causes a momentary electromotive force (a consequence of Faraday's law), which modifies the electronic orbitals of atoms/molecules in a substance in such a way, that the orbitals produce an induced magnetic field, which opposes the applied field (a consequence of Lenz's law). However, the induced magnetic moment is very small in most everyday materials.
Diamagnets are repelled by magnetic fields. However, since diamagnetism is such a weak property its effects are not observable in every-day life.
However, in Magnetic Resonance Imaging for example barium sulfate suspensions lead with its weak negative magnetic susceptibility to a decrease in signal. See also magnetism, ferromagnetism, paramagnetism, and superparamagnetism.

spacer

• View the DATABASE results for 'Diamagnetism' (7).Open this link in a new window

 
Further Reading:
  Basics:
Magnet basics
   by my.execpc.com    
Diamagnetism
   by en.wikipedia.org    
MRI Resources 
Lung Imaging - Health - Cardiovascular Imaging - Pregnancy - MRI Centers - Hospitals
 
Magnetic SusceptibilityForum -
related threads
 
(c) Magnetic susceptibility is the degree of magnetization of a material in response to a magnetic field. Paramagnetic materials strengthen the magnetic field, diamagnetic materials weaken it. The magnetic susceptibility of ferromagnetic substances is not linear; this is called differential susceptibility.
Differences in magnetic susceptibilities are a frequent cause of MRI artifacts.
See also Susceptibility Artifact, Magnetism, Diamagnetism, Paramagnetism, Ferromagnetism.
spacer

• View the DATABASE results for 'Magnetic Susceptibility' (15).Open this link in a new window

 
Further Reading:
  Basics:
Metal-Induced Artifacts in MRI
   by www.ajronline.org    
Magnetic susceptibility
   by en.wikipedia.org    
MRI Resources 
Veterinary MRI - Liver Imaging - Colonography - Calculation - MRCP - NMR
 
Magnetism
 
Magnetic forces are fundamental forces that arise due to the movement of electrical charge. Maxwell's equations describe the origin and behavior of the fields that govern these forces. Thus, magnetism is seen whenever electrically charged particles are in motion. This can arise either from movement of electrons in an electric current, resulting in 'electromagnetism', or from the quantum-mechanical orbital motion (there is no orbital motion of electrons around the nucleus like planets around the sun, but there is an 'effective electron velocity') and spin of electrons, resulting in what are known as 'permanent magnets'.
The physical cause of the magnetism of objects, as distinct from electrical currents, is the atomic magnetic dipole. Magnetic dipoles, or magnetic moments, result on the atomic scale from the two kinds of movement of electrons. The first is the orbital motion of the electron around the nucleus this motion can be considered as a current loop, resulting in an orbital dipole magnetic moment along the axis of the nucleus. The second, much stronger, source of electronic magnetic moment is due to a quantum mechanical property called the spin dipole magnetic moment.
Gauss (G) and tesla (T) are units to define the intensity of magnetic fields. One tesla is equivalent to 10 000 gauss.
Typically, the field strength of MRI scanners is between 0.15 T and 3 T.
See also Diamagnetism, Paramagnetism, Superparamagnetism, and Ferromagnetism.
Radiology-tip.comGamma Ray,  Electromagnetic Radiation
spacer
Radiology-tip.comSonographic Features,  Echo
spacer

• View the DATABASE results for 'Magnetism' (18).Open this link in a new window


• View the NEWS results for 'Magnetism' (1).Open this link in a new window.
 
Further Reading:
  Basics:
Magnet basics
   by my.execpc.com    
  News & More:
What affects the strength of a magnet?
   by my.execpc.com    
MRI Resources 
MRI Technician and Technologist Jobs - Sequences - Mobile MRI Rental - Examinations - Movies - Services and Supplies
 
     1 - 5 (of 7)     next
Result Pages : [1]  [2]
 Random Page
 
Share This Page
FacebookTwitterLinkedIn

MR-TIP    
Community   
User
Pass
Forgot your UserID/Password ?  



Acoustic Noise Reduction (Silent, Quiet, etc.) :
cannot get better 
is in its first steps 
is done by earplugs, headphones 
must get better 
is bad, I miss something 
is unnecessary 

Look
      Ups





MR-TIP.com uses cookies! By browsing MR-TIP.com, you agree to our use of cookies.

Magnetic Resonance - Technology Information Portal
Member of SoftWays' Medical Imaging Group - MR-TIP • Radiology-TIP • US-TIP • The-Medical-Market
Copyright © 2003 - 2016 SoftWays. All rights reserved. [ 18 February 2018]
Terms of Use | Privacy Policy | Advertising
 [last update: 2018-02-01 02:59:00]