RF controversy!

[AndrewBworth]

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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-If it helps - I remember Slichter writes something about this in his book - Principles of Magnetic Resonance. If I recall though - only the magnetic component of the RF radiation interacts with the spin, and of that magnetic component, only half are rotating in the same sense as the precession of the spin, so only these waves matter. Thanks for bringing this up!