Magnetic resonance imaging (MRI) is the application of nuclear magnetic resonance to produce images. MRI is now a common, though relatively expensive, diagnostic technique. MRI images can be very detailed and informative and the technique is non-invasive and it does not use highly energetic and potentially dangerous ionizing radiation. Because of the association many people make of the term nuclear with dangerous radiation, the term nuclear was eliminated from the original term for the technique (nuclear magnetic resonance imaging).

Nuclear magnetic resonance was developed in the 1950s by physicists as a means of probing the properties of the atomic nucleus. Theoreticians predicted that nuclei with particular ratios of protons and neutrons, giving rise to non-zero nuclear spin numbers, would show an asymmetry, or anisotropy, in a magnetic field that would result in a greater number of nuclei aligned in one direction relative to the...