Digital technology has revolutionized our lives. We are collecting, storing, analyzing, and using more and more information at a faster and faster pace. X-ray imaging is no exception, whether it is for medical diagnosis, security screening, or industrial inspection. The benefits of digital X-ray imaging are clear. Doctors are already using it to see “real-time” movies of their patients’ anatomy and physiology. They can watch blood flowing through vessels and into organs or monitor the gastrointestinal tract to diagnose conditions that require treatment. Better still, doctors are using this imaging capability during treatment to see exactly where to target cancerous tumors with radiotherapy beams or where to place the instruments and devices that will cure their patients.
      The value of this real-time X-ray vision goes beyond medicine to many other scenarios, including industrial inspections in which technicians take instant snapshots of the internal structures of objects such as electronic circuits and mechanical parts.
      While progress has been rapid in recent years, companies like Varian Medical Systems are now using solid-state digital technology in the form of amorphous silicon flat-panel X-ray detectors to achieve even more dramatic improvements that will extend the utility of digital X-ray imaging systems. These panels obtain instant high-resolution “still” X-ray images (radiographs) as well as “live,” or moving, X-ray images (fluoroscopy) for display on computer monitors or storage in electronic archives.
      Today, most medical centers are still hampered by a continuing reliance on film for obtaining, displaying, and storing radiographic X-ray images. In the digital age, this technological relic of the analog age is viewed as inefficient; it requires processing chemicals, storage space, and perhaps most important – time. Other centers are digitizing X-ray images using computed radiography, which requires several time-consuming steps before an image can be viewed. Furthermore, many centers rely entirely on separate systems for obtaining fluoroscopic images.
      Hospitals have been generating live fluoroscopic images for years, using X-ray systems equipped with image-intensifier tubes. This now-common approach, which has been evolving since the first image intensifiers were introduced in the 1960s, has resulted in an annual multi-million dollar image-intensifier tube industry. The technology has some drawbacks, however. Image-intensifier tubes generate circular images that suffer from a loss of resolution at their periphery. Furthermore, the up-to-100-pound heft and barrel-shaped bulkiness of these tubes require large supports that are cumbersome to work around when doctors are treating patients. This can be particularly difficult in trauma centers, for instance, or in surgery, where doctors need very close access to their patients and the ability to maneuver around them.