ABSTRACT
Nuclei are positively charged. Some have a property termed spin and are called nuclear spins. A nuclear spin generates a magnetic field in the same way that a current circulating round a loop will generate a magnetic field, rather like a tiny bar magnet. Magnetic resonance images are normally formed from signals arising from hydrogen nuclei (1H), mainly because they are so much more abundant in the body than any other nucleus capable of undergoing nuclear magnetic resonance (NMR) and so give a much stronger signal.
