I learned this from watching House. I am certain that it's true, but I also kind of wonder how much backpressure there is against this kind of thing because the scanners are also insanely expensive to run per minute.

This backpressure is even with cheaper devices such as x-rays etc.

The backpressure on x-rays is because dosing yourself with radiation on a regular basis is a really great way to generate health problems in the course of trying to find some. There's a reason x-ray operators and anyone in the room with the patient get given lead lined aprons to wear while the machine is active.