Because a radiograph is a photographic negative, the shadows of the bones show up as light areas. Other parts of the body allow more X rays through than the bones do and so cast shadows in varying shades of gray. In another process, called digital imaging, detectors measure the X rays that pass through the body and send this information to a computer. The computer converts the data into an image that is displayed on a monitor. The machine shoots a pencil-thin beam of X rays at the body from many angles.
Detectors measure the rays that pass through and send the measurements to a computer.
The computer then uses the measurements to create the images. In industry, inspectors use X rays to examine products made of various kinds of materials, including aluminum, steel, and other cast metals. Radiographs reveal cracks and other defects inside the products. Workers also use X rays to check the quality of mass-produced products, such as computer chips and other small electronic devices. Scanners at airports use X rays to check baggage for weapons or bombs.