MRI, or the Magnetic Resonance Imaging, is a machine that doctors use that provides an unparalleled view inside the human body, using the physics of magnets and radio waves. It is normally used to diagnose many types of injuries and conditions. The patient lies down on a horizontal table that slides into the MRI machine. Inside the table is a magnet with a tube running through it known as the bore of the magnet. The scan begins when the body part to be scanned is in the isocenter of the magnetic field of the machine. .
MRI scans the body by making use of the millions of small biological "magnets" we have in our own bodies: the proton, the nucleus of the hydrogen atom. MRI first neutralizes the body by creating a steady magnetic field that is thirty thousand times stronger than the earth's own magnetic field. Then, in order to change the orientation of protons from their steady state, MRI emits radio waves, and shortly after, reads the "body's electromagnetic transmissions at a selected frequency" (Encarta.msn.com). With these pulses of energy, the MRI scanner can evaluate the body tissues point by point, creating a 2- or 3-D map of the tissues.
MRI has greatly advanced the ability to view human tissue, because it can generate images of any part of the body from any angle, without surgical cutting and in a shorter period of time. It also causes comparatively little damage to cellular structure. The photons from MRI waves only have energies of about 10^-7 eV, while x-rays can range from 10^4 to 10^6 eV. Even though MRI is more expensive, the cost is worth the value of the clear, detailed information it provides and the relative safety it. MRI owes this value to the science of physics, though, because without physics, there would no application of magnets and radio waves and protons and frequency, all of which contribute to the success of MRI.