> X-raying PCBs and then diffing them against clean PCBs is a worthwhile thing to do if you're concerned about hardware backdoors, or 'interdiction' of hardware in a supply chain. I do this sometimes when ordering super-critical equipment like Thinkpads from the U.S as you never know what lurks on the motherboard (keyloggers, etc).

I'm curious - how does one go about buying or getting access to an x-ray machine (and how much does that cost)?