Many radiation treatment centers use these- I saw one today, as a matter of fact. The treatment rooms are (naturally, as they are lined with 12" lead) windowless, dark (so setup lasers can be seen by therapists), and filled with machines that are likely intimidating when pointed directly at you (the patient).

If anyone's interested, the machine pictured is a CyberKnife: Basically, an industrial robot (though tolerances are changed significantly) with a 6MV linear accelerator on the head which can deliver stereotactic radiation treatments, which are designed to deliver high doses of radiation in very few fractions.

What? No? Your badge says to protect and SERVE, does it not, officer?