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Searchterm 'Frequency' was also found in the following services of MR-TIP.com:  
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FrequencyForum - related threads
 
(F) The number of repetitions of a periodic process per unit time. It is related to angular frequency, w, by f = w/2p. In electromagnetic radiation, it is usually expressed in units of Hertz (Hz), where 1 Hz = 1 cycle per second.
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Radio FrequencyForum - related threads
 
(RF) Radio frequency refers to that portion of the electromagnetic spectrum in which electromagnetic waves can be generated by alternating current fed to an antenna.
The RF pulses used in MRI are commonly in the 1-100 megahertz range, and their effect upon a body is potential heating of tissues and foreign bodies, such as metallic implants, mainly at the surface.
This is a principal area of concern for MRI safety limits caused by absorption (see specific absorption rate) of the applied pulses of RF energy.


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The higher the frequency, the larger will be the amount of heat developed.
The more ionic the biochemical environment in the tissue, the more energy that will be deposited as heat.
This effect is well known for homogeneous model systems, but the complex structure of various human tissues makes detailed theoretical calculations very difficult, if not impossible. By scanning problems, it is important to verify the transmission frequency. If the RF transmitted into the patient was, e.g. 5000 Hz lower than the resonance frequency of the protons, no protons was excited, and no signal returns.
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Further Reading:
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Radio frequencyOpen this link in a new window
   by en.wikipedia.org    
MRI SafetyOpen this link in a new window
   by imaging.ugent.be    
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Radiologists Offer Non-surgical Treatment For Early-stage Liver CancerOpen this link in a new window
Saturday, 5 March 2005   by www.sciencedaily.com    
 •• There are 2 news about 'Radio Frequency'.
Searchterm 'Frequency' was also found in the following services of MR-TIP.com:  
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Frequency Offset
 
The difference between given signal frequency and a reference frequency.
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Larmor Frequency
 
The Larmor precession frequency is the rate of precession of a spin packet under the influence of a magnetic field. The frequency of an RF signal, which will cause a change in the nucleus spin energy level, is given by the Larmor equation. The frequency is determined by the gyro magnetic ratio of atoms and the strength of the magnetic field. The gyromagnetic ratio is different for each nucleus of different atoms.
The stronger the magnetic field, the higher the precessional frequency. If an RF pulse at the Larmor frequency is applied to the nucleus of an atom, the protons will alter their alignment from the direction of the main magnetic field to the direction opposite the main magnetic field. As the proton tries to realign with the main magnetic field, it will emit energy at the Larmor frequency. By varying the magnetic field across the body with a magnetic field gradient, the corresponding variation of the Larmor frequency can be used to encode the position. For protons (hydrogen nuclei), the Larmor frequency is 42.58 MHz/Tesla.
See also Larmor Equation.
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Further Reading:
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Magnetic resonance imagingOpen this link in a new window
   by www.scholarpedia.org    
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The resonance property of the hydrogen nucleusOpen this link in a new window
   by www.es.oersted.dtu.dk    
Searchterm 'Frequency' was also found in the following services of MR-TIP.com:  
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Angular Frequency
 
Frequency of oscillation or rotation (measured in radians/second) commonly designated by the Greek letter w: w = 2pf, where f is frequency (in hertz (Hz)).
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