cr introduction

CR Introduction

CR uses an imaging plate coated with storage phosphors to capture x-rays as they pass through the patient. Trace amounts of impurities are added to the phosphor materials in a process called "doping," to alter their crystalline form and physical properties. When irradiated, the enhanced phosphors absorb and store x-ray energy in gaps in their altered crystal structure. This trapped energy comprises a latent image; when stimulated by additional light energy of the proper wavelength, the trapped energy is released.

In modern CR systems, storage phosphors commonly are stimulated with a low-energy laser to release visible light wherever x-rays have been absorbed. This light is captured and converted into an electrical signal, which is converted to data that can be transmitted to remote systems or locations, displayed on laser-printed films or softcopy workstations and stored digitally.

An X-ray with Vision

Other than the absence of film and chemical processing, from the technician's and the patient's perspectives, computed radiography - including equipment for capture - works very much like conventional film-screen radiology. The difference is in the benefits.

Phosphor plates, like film, are stored in cassette format. In fact, existing analog equipment, from generators to x-ray tubes, examination tables and upright chest exam systems, can be used with a CR system. Technicians simply insert a CR cassette instead of a film cassette, take the x-ray, and then transfer the exposed cassette with x-ray images into the CR unit that scans and translates the contents into data, to be sent to soft copy display, archives, or hard copy print-out.

Compared to conventional film-screen capture, CR technology speeds image availability and can reduce image retakes and duplication costs, to boost workflow and productivity. CR also offers more options for displaying, sharing and storing images.

From the core precepts of storage phosphor-based image generation, improvements in phosphor screen coating, optics and scanning systems, and image data processing have increased the sophistication of computed radiography. Kodak scientists' contributions in many areas have helped make it possible for self-contained hardware and software systems to handle every step from image acquisition to display. In general, CR systems are getting smaller and faster, to handle heavy patient loads in tight spaces, such as emergency rooms or intensive care units.

The Next Step

Kodak experts are continuing to refine aspects of CR to address industry challenges including the types of exams possible, such as "long length" imaging. Not long ago, physicians requiring hip-to-foot, full spine or other "long length" images needed to use film-based image capture - along with attendant chemical processing and film handling. Kodak recently introduced fully automatic stitching software and cassette positioning system that delivers images up to 17 inches wide by 51 inches long (43 x 129 cm), with few, if any, visible seams. The results can be viewed in soft copy or printed on film using a Kodak DryView laser imager for viewbox display.

In an ongoing commitment to digital imaging, Kodak continues to refresh CR technology quickly, applying its innovation and expertise to meet the needs of hospital radiology centers and diagnostic facilities - whether they are high-traffic, cutting-edge teaching schools, or low-volume operations with specific cost requirements. Since 2000, Kodak has introduced three DirectView CR systems for single- or multi-plate image capture and high-volume image generation and processing, with additional new product offerings expected by the end of 2003.

Efficiency - better workflow and greater productivity - remains a top priority for healthcare providers. For those facilities that have adopted CR, further advances in system capacity and image processing capability contribute to quantity and quality of images, so that the time to produce images is reduced, and the number of radiography sessions completed is increased. Kodak pioneered remote operations panel display equipment that allows radiology technicians to perform most system functions while away from the main CR unit. Images may be reviewed or accessed from an examination room as if the technician were using the primary CR system itself. Other software makes it possible for demographic data to be entered by department administrative personnel, to make the best use of technician's time.

Advances in image science also make it possible for radiology centers to improve operations without huge capital investment; for example, Kodak recently introduced third-generation software for image enhancement and processing. Along with these improvements, the cost has come down, and CR systems with better functionality are available at half the price typical just five or six years ago. These changes further encourage adoption of CR by healthcare providers.

As CR was becoming more standard in hospitals and diagnostic centers, Kodak scientists began work several years ago on the next wave of radiographic imaging technology: Digital, or direct, radiography (DR). DR systems feature a detector that has the capability to produce images very quickly, either through a similar phosphor stimulation process or by a special material that converts x-ray energy directly to a charge that is read by a semiconductor. Indeed, adoption of Kodak CR technology could help customers more quickly embrace DR technology. Kodak is commercializing this next generation of radiography technology to leverage the familiar functional aspects of its CR systems, so that DR will be easy to incorporate into existing radiology practices and workflow.