You know of course that the cell phone system in Europe is different from the US. Here, there are signs at the front door of all hospitals (and in many places inside) saying 'Mobile phones MUST be switched off'. The idea is that they can interfere with various medical equipment. I don't know if that is true, or if it is like the prohibition on airplanes -- but in any case, that's the rule. And most people follow it.
Having said that -- my wife is a nurse and in her hospital the staff do have cell phones. They are called DECT and apparently they use a sub-set of the frequency band that is sure to not conflict with all the monitors, analyzers, etc. in the building.
Can the public use their own personal mobile phones in American hospitals?
Cheers,
Henry