Hologic makes a great Bone Densitometer. As a matter of fact, from their QDR-4500 series introduced in 1995, to their Discovery series, still manufactured today, Hologic has arguably had the most reliable DEXA scanner on the market.
And a lot of that reliability has to do with Hologic’s X-ray Tube and High-Voltage Tank assembly. As the beating heart of the Hologic DEXA, the X-Ray tube is enclosed in an oil-filled tank, which both cools the tube and prolongs its life.
Since these two assemblies are inextricably connected, both literally and figuratively, you can’t separate one from the other. This is why you’ll hear some people call this assembly a tank, while others call it a tube. Really, it is both!