A sharper magnetic window into the body.

Though increasingly common in mainstream medicine, magnetic resonance imaging (MRI) has its limitations.

To produce an image, MRI must detect very faint signals arising from the gyrations of atoms in a magnetic field-a phenomenon known as nuclear magnetic resonance (NMR). As atoms align themselves "up" or "down" with respect to the field, they vibrate, creating signals that reveal their location.

Alexander Pines, a chemist at the University of California, Berkeley, and his colleagues have developed a method of amplifying the NMR signal of biological molecules. They use a laser to energize and polarize xenon gas, which they then dissolve in solution. They mix the solution with samples of organic molecules and find that the xenon atoms magnetically polarize neighboring molecules, amplifying their NMR response, the scientists say in the March 29 Science. To make the technique medically useful, they envision administering energized xenon to patients by inhalation or ingestion.