I looked up the term "X-ray table" but couldn't find anything relevant except very recent results about this specific news.
Sounds like FBI invented this very stupid/confusing name for the story when they could have used much something much better and clearer. X-ray really has nothing to do with this.
I remember as a kid seeing comics imported from the US that had ads for "x-ray specs". My first clue that the US advertising standards were not quite the same as other countries. Perhaps it's a similar idea to that?