With CR and DR the dose can be increased by two to four times, or more, and it is difficult to observe a difference in the image. With screen-film imaging an increase in dose usually means the film becomes darker, until the point at which it is unusable. Patient dose is a concern in digital imaging, both CD and DR. Appropriate display hardware and quality control is essential to obtaining consistent, diagnostic information in digital images. The display of the image becomes another important aspect of CR and DR. It is important to understand the difference and advantages of these systems, one of which is reduced cassette handling for the radiographer in the clinical setting.
These technologies differ only in terms of the image sensor and the way the image is converted to a digital signal. The other technology uses a photoconductor, such as amorphous selenium (aSe) to directly convert the detected x-rays into an electronic signal. The TFT array converts the light emitted from the phosphor into digital signals. One technology uses a light emitting phosphor which is in intimate contact a thin-film transistor (TFT) array. CR is less efficient in terms of image quality for a specific patient dose due to the initial storage, and the stimulation and readout, of the image information.ĭR is a more efficient system. This stimulation results in the emission of light which is captured and digitized to produce the digital array. This stored image is then stimulated by a laser beam with a very small focus (0.1 mm or less).
#Ase exposure x psp
These systems rely on picture archiving and communication systems (PACS) for transmission and storage of the digital images.ĬR systems use a PSP plate to store the image resulting from the interaction of x-rays with the phosphor. DR uses a solid-state detector, or a combination of a light emitting phosphor and a digital converter, which produces digital array and image.Īll other aspects of these two technologies are similar including the computer processing of the digital image, transmission and display of the digital image, and digital image storage. CR uses photostimulable phosphor (PSP) plates which must be transported to a digital scanner (or reader) and scanned with a laser beam to convert the stored image to a digital array. Both are similar in technology except for the image receptor. Go Back Computed radiography and digital radiography IntroductionĬomputed radiography (CR) and digital radiography (DR) are rapidly replacing screen-film imaging systems in many countries. Physics and Technology of Medical Imaging (Online Textbook).Digital Mammography: An Overview, 2004 (AAPM/RSNA).Advances in Digital Radiography: Physical Principles and System Overview, 2007 (Journal Article).Handbook on the Physics of Diagnostic Radiology, 2014 (IAEA).An Exposure Indicator for Digital Radiography, 2009 (AAPM).
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