Working in his lab's basement, Rosen built his MRI from copper wire and sheets of aluminum. Very little magnetic energy is needed to rotate the helium enough to create a high-resolution image, allowing Rosen to forgo million-dollar superconducting magnets. As a result, his machine is 1/20 the cost of a typical MRI scanner. That price cut could put it in the hands of every pulmonologist, who could use it to examine asthmatics during an attack to gauge the effectiveness of medication or screen patients for chronic obstructive pulmonary disease, which often goes undiagnosed until its symptoms are irreversible. "It's rare that the cheaper thing is better than the expensive thing," Rosen says. "But we're getting the first real pictures of lungs."