With our relatively weak magnet, the prototype moves 0.2 inches per second in a dish of saline. If it were in the blood stream—cleaning out your arteries, for example—you'd need a stronger magnet to overcome the flow of blood. But that is still a ways off. In the near term, we imagine using the device to image the GI tract; there, it wouldn't need to travel as fast. It could reduce the cost of cancer screenings, and it would be a welcome alternative to at least one traditional method: colonoscopy."