don't those have giant magnets....

That'd be an MRI.

A CT is, simplifying, an x-ray machine that takes lots of images in slices, then analyze them with certain algorithms to reconstruct 2D and 3D images of the interior of the 'subject'.

	▲	cenamus 3 days ago \| parent [-]
		Well, not really in slices, but from all angles. So with a computer you can reconstruct the density of whatever you're imaging and also do the slices