Earlier quoted context omitted.
You know slightly different NMR machines are used to scan entire humans, right? They only really differ in scan pattern for this aspect. That's IIUC just a software change.
Afaik not really. The ones that scan humans are tuned for a specific proton resonance frequency, so they basically measure hydrogen density. But you get a 3D-Plot because they do a computed tomography of that density. The chemistry NMRs are spectrographs, so you dial through a whole frequency spectrum and look at the reflected/transmitted signal. With that you get different peaks for different nuclei plus some deviat…
Also proton frequency only....