I think it is possible with the next 50 years. Many medical technologies are so small that they can be held between your fingers. These techs are not on the nano-scale as far as technology goes but represent the capacity for miniature devices to create great benefits to us in medicine. Also, with the advancement of processing power in computers and ultimatley AI, advancement of technologies will pass through unprecedented stages with many unknown results. Some people believe that nano tech is already at this point, I have not learned about any applied nano-tech as of yet

I would be cool with the tech being used on me if it were worth it and there was no possibility for the machines to use me as material for self replication (scary thought)

If we follow the theory of Moore's Law that the number of transistors per square inch on integrated circuits had doubled every year since the integrated circuit was invented and apply it to other similar fields of science- namely fitting as much knowledge, competence, and autonomy as possible in a small machine- than the progress is not just possible, it may even be inevitable. Our curiosity is forcing us to push bounds that we never even imagine just two or three decades ago. We want to manipulate everything from outside in and we want it to be as fast, financially efficient, and useful as humanly possible- and perhaps even more.