By Peter Weiss
Like modern doctors, magnetic resonance imaging (MRI) scanners don’t do house calls. They and related nuclear magnetic resonance (NMR) instruments for chemical analysis require that a patient or sample come to a lab or clinic and squeeze into the inner recesses of a machine.
Although a few small magnetic resonance probes exist for field applications such as checking tires’ stiffness, those sensors glean only crude information from their subjects compared with what conventional scanners can do, according to Bernhard Blümich of RWTH Aachen University in Germany. To do better, such devices would have to generate more-uniform magnetic fields.