Medical imaging is an interesting field. There are things like fMRI, PET scans, CAT scans, radioactive dye traces, and a million other different techniques — but they’re usually so limited and specific (as extraordinary as they are) that there’s always a need for a new one. In this case it’s soft X-ray tomography, a variant on the more familiar CAT scan.
Normal X-rays penetrate too effectively for them to be used on individual cells; the amount of interference provided by the cell is simply not enough to detect and create an image from. So they use soft X-rays, which have a slightly longer wavelength than the kind used on a broken arm. A new technique developed by Lawrence Berkeley National Laboratory has enabled soft X-ray images to be taken quickly and sequentially, and then assembled into a 3D model of the subject.
It’s not “live” like an fMRI, and it doesn’t provide the detail one finds in electron microscopy, but obviously it’s very useful. I doubt any of us will ever run into one of these machines in real life, but it’s cool to know they exist.