It’s hard to get an X-ray image of low-density material like tissue between bones because X-rays just pass right through like sunlight through a window. But what if you need to see the area that isn’t bone? Sandia National Laboratories studies myriads of low-density materials, from laminate layers in airplane wings to foams and epoxies that cushion parts. So Sandia borrowed and refined a technique being studied by the medical field, X-ray phase contrast imaging, to look inside the softer side of things without taking them apart.