Magnetic resonance imaging (MRI) is an extraordinary tool, but it has important limitations. For example, the spatial resolution of this technique is generally not good enough for breast imaging.
Of course, the spatial resolution can be improved with higher-strength fields. But the U.S. Food and Drug Administration places strict limits on the field strengths that can be used on humans because of the risks of hotspots being generated in the body. So various groups are looking at ways to improve spatial resolution without increasing magnetic field strengths.
Which is how we come to the work of Manuel Freire at the University of Seville in Spain. He and some amigos have found an interesting way to boost the resolution of an MRI device: they use a lens to focus radio-frequency magnetic fields.
The lens is a metamaterial slab made of a repeating periodic structure, the details of which the authors do not give.
However, the results are clear to see in images showing the focusing slab placed between the knees of one of the authors. Freire and his colleagues say that placing a lens between the breasts could similarly improve the resolution of breast images. That’s a potentially important and useful breakthrough.
Ref: arxiv.org/abs/0907.2795: Metamaterial Radiofrequency Lens for Magnetic Resonance Imaging