Body & HealthHow it works
How an MRI looks inside you without X-rays.
A magnetic field of typically 1.5 or 3 tesla lines up the hydrogen nuclei in your body. Radio pulses tip them over; as they return they emit a signal. Gradient fields reveal which location it came from. Because different tissues relax at different speeds, you get contrast – with no ionising radiation at all.
Useful: Lauterbur and Mansfield won the 2003 Nobel Prize for giving that signal an address.
Source: en.wikipedia.org