This medical pod (or med pod) is definitely a medical device of the future. The movie happens in 2100. Science and technology had time to do giant steps forward since now. The pod is able to do a surgery from A to Z without human intervention.
Yet, we don't know if it is able to do a diagnosis 100% alone. Elizabeth, the character who uses it, gives instructions to the pod before beginning the surgery. However David, another character who is an andoid, is able to take decisions of its own. So does probably the medical pod. In 2100 artificial intelligence is advanced enough to have computers do diagnosis.

Near future?

Even if the medical pod technology is out of reach for us, poor humans of 2012, it doesn't seem so far from us. Compared to spaceships, which use physics laws that we've not discovered yet, like time warp, the technology in the medical pod doesn't need new physics laws.
It uses sensors to see in the body, we have them.
It uses surgery tools, we have them.
It uses computers, we have them.
Look at IMRIS machines and you'll see what I mean. What separates us from a machine of this kind in the future is:

  • surgery tools that are really versatile and multi purpose
  • the miniaturization of many components
  • the combination of all components to build an integrated system
  • the artificial intelligence and the computer system able to control the whole.

Some technology gaps are not so big. For artificial intelligence, I doubt that we're able to let a computer do the diagnosis instead of a human. We needed decades to replace subway drivers by computers based on finite state machines. The gap is also psychic and cultural!
Confidence. This probably what separates us the most from an automatic diagnosis and surgery tool.