I work at a medical device consultancy, but we're mostly developing custom Class B/C devices at the bare metal level. It sounds like you'll be developing a Class A device and cost isn't a huge issue so I'd probably recommend going the Android route. Find a reputable supplier who's worked with medical devices before, and check their availability guarantee (since the production lifetime of most Android devices is short).

Class A basically means follow common sense, so as long as document your architecture/design, use source control and test critical parts of the code you should be right to use whichever Android development framework you want.