The idea of digitising human bodies inspires both dreams and nightmares. In the 1966 film Fantastic Voyage, a spacecraft and its crew are shrunk to microscopic size and injected into the body of an injured astronaut to remove a life-threatening blood clot from his brain. The Academy Award-winning movie—later developed into a novel by Isaac Asimov—seemed like pure fantasy at the time. However, it anticipated what could be the next revolution in medicine: the idea that ever-smaller and more sophisticated sensors are about to enter our bodies, connecting human beings to the internet.