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RF controversy!
02-11-2015, 07:09 AM
Post: #1
RF controversy!
Dear all,

If my understanding is correct, D.I Hoult has shown http://www.mri-q.com/uploads/3/2/7/4/327...42_ftp.pdf that the MR signal (current) is driven by a circulating electric 'near' field that follows Faraday's law of induction. In other words, it is induced by a time varying magnetic field (precessing magnetic moments).
On the other hand, the electric 'far' field induces a perpendicular magnetic 'far' field. Moreover, both these 'far' fields can be shown to be the components of an electromagnetic RF wave.
What I don't understand is why the 'near' electric field can't be induced by a fluctuating magnetic field of an RF wave.
If no RF is emitted by the spins, then does that mean that no RF was absorbed to begin with? And if that's the case why are RF pulses used in MRI in the first place?

As the title says, it is a controversial issue but I would appreciate an additional insight to the subject.

Thanks in advance.
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Messages In This Thread
RF controversy! - univox_high_flyer - 02-11-2015 07:09 AM
RE: RF controversy! - AndrewBworth - 07-24-2015, 07:06 AM
RE: RF controversy! - aelster - 05-30-2016, 05:34 PM
RE: RF controversy! - mmm - 08-30-2017, 03:54 PM
RE: RF controversy! - embermoon - 01-11-2018, 01:53 PM

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