Radiography (or X-rays) is the most common form of diagnostic imaging available. The principal benefit is that it is a relatively cheap process and the bones of the horse can be easily visualised. Radiography can also be used to identify areas of soft tissue as well but typically denser objects show up most clearly.
Once an area has been isolated as a site of injury, it will be radiographed (or X-rayed) to aid further diagnosis. Radiographs are produced by passing X-rays through the body onto an X-ray sensitive film. Dense objects prevent x-rays passing through them and, consequently, they cast a shadow onto the film. This film is then developed to produce an image of the region. Digital radiography is now becoming more common in veterinary practices. The difference is that the film is replaced by a sensor that generates a digital image on a computer. This change is very similar to the change to digital cameras away from traditional film cameras.