Radiologists developed a new method for viewing the lungs of asthma sufferers. The method uses a polarized helium-3 gas--making it visible during an MRI. The patient inhales the helium-3 and undergoes an MRI, where doctors can see how far the atoms in the gas can travel in the lungs. This gives an image of what airways are blocked and what parts of the lungs ventilate. The black areas of the image indicate portions of the lung where air does not reach--areas where the helium-3 atoms could not travel.