I have no idea what they are either, but it looks pretty amazing.
Based on the watch in the image below, that chunk of meat and bone must be a cross section through a hand/wrist.
This is supposed to be 3D as well. Do you take that to mean 3D like a CAD model which can be rotated and viewed from all sides? Or 3D like those stereo images that appear to have depth after crossing your eyes?
Image from: http://www.likecool.com/First_3D_Colour_XRays_Unveiled--Other--Gear.html
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