Computed Radiography (CR) or Digital Radiography (DR)?

Published On - September 11, 2018

James Ashworth Blog

Computed Radiography (CR) uses a flexible phosphor imaging plate to capture digital images instead of using conventional film. CR is an indirect form of digital imaging that uses a cassette system similar to conventional film-screen radiography. The imaging plate is exposed to x-ray radiation and the phosphor layer within the plate stores the image. As the imaging plate is read by the scanner, a focused layer releases the stored image in the form of visible light photons, which are collected and amplified by the scanner, converted to a digital signal, and then transferred to a computer for processing and viewing.

While CR does have some benefits over conventional film x-ray technology, it does come along with some cons, which include:

  • Long time from exposure to viewing of image

  • Resolution not as high as DR

  • Risk of overexposure

  • Moving parts can be damaged and require maintenance

On the other hand, Digital Radiography (DR) uses a digital image capture device, such as a Flat Panel Detector (FPD), instead of photographic film to capture an image using a sensor and then rendering that image on a computer. Indirect FPDs commonly consist of an amorphous silicon detector with a scintillator layer comprised of cesium iodide (CsI), which converts x-rays into light. The image is then read, digitized, and transmitted out of the detector, passed through image processing algorithms to produce the desired image on a viewing screen. One of the clearest advantages of DR over CR is that the resulting images are available for viewing almost immediately (within seconds).

The benefits of DR are plentiful:

  • Superior, high quality high-resolution images

  • Ability to enhance images with software tools

  • Significantly reduces radiation dose

  • Gets rid of film and processing chemicals

  • Retrofits are often possible without major upfront costs

  • Significantly reduces processing time (by as much as 95%)

  • Improved workflow and increased efficiency = higher patient throughput

  • DR panels can be shared across multiple systems and modalities

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