Medical technology may have improved a tad in the last century, but the humble X-ray machine, whose basic principle was discovered in 1895 by the German physicist Wilhelm Conrad Roentgen, has hardly changed--until this past year, when Larry Antonuk of the University of Michigan and Robert Street of Xerox parc in Palo Alto, California, put the finishing touches on the first digital X-ray machine. The new device retains some of the advantages of conventional X radiology--it is cheap compared with mri and ct scanners, for instance, and it doesn’t require patients to lie still for ages--and picks up a few more. By replacing film with far more sensitive electronics, it produces X-ray images with only about half the amount of radiation. In addition, those images are easier to store, copy, and send to doctors near and far, and poor images can be enhanced with computers.
After X-rays from Antonuk and Street’s device pass through a patient’s body, they fall on a thin sheet of fluorescent material that converts them into visible light, which in turn activates an array of silicon cells. The glasslike cells, only one twenty-five-thousandth of an inch thick, convert the light into electric signals--stronger ones where a lot of X-rays have passed through soft tissue, and weaker ones where the rays have been blocked by bone. The signals are relayed to a computer, which constructs the full image immediately.
The inventors expect the device to hit the marketplace as early as late 1997. The first X-ray images were made on plates of glass, Antonuk says, and now, a hundred years later, X-ray images are going to be made on plates of glass again. But the plates of glass are digital and real-time.