Bjorn Redfors
Sat. 27 Jun.09, 12:31
[Start of: '90 excitation pulse vs 180 inversion pulse' 11 Replies]
Category:
Basics and Physics |
90 excitation pulse vs 180 inversion pulse |
Im a medical student interested in diagnostic medicine and aim to understand (on some level) the basics of MRI theory but lack an advanced physics background.
Why are the "spins" "brought into coherence" by the 90 excitation pulse but not by a 180 inversion RF pulse?
And how is the 180 inversion pulse explained on the nuclear level, i.e. "paralell/antiparalell" orientation of single nuclei (is it possible by such a simple model?)?
Is it possible to explain this "in layman's terms"?. I find that most texts (at least those written for physicians) omit proper explanations of this.
Thank You!
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