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Digital radiography!

Carlton/Adler CH 25

What does "CR" mean Computed Radiography
What does "DR" mean Direct Digital Radiography
What is the difference between CR and DR equipment? CR is indirect meaning the radiographer must move the detector between image acquisition and display. DR is direct meaning the detector and reader are a permanent part of the table or wall; therefore a cassette is not needed.
What is a scintillator? A compound that absorbs x-rays and converts the energy to visible light by fluorescence.
What is the function of a scintillator? To convert incoming x-ray photons to light
What is PSP? Photostimulable storage phosphor imaging plate
How many layers make up a PSP? Six
What are the layers and in what order? Protective layer, Phosphor layer, Conductor layer, Support layer, Light shield layer, and Backing layer
What is the active component of an imaging plate and why is it called "active"? Phosphor layer; photostimulable phosphor
How is a latent image created utilizing CR? By energy transfer during photoelectric interactions
When will an exposed IP begin to lose its energy? An average of how much energy will be lost? In 8 hours, 25%
Why erase an IP? To eliminate unwanted noise
How is an PSP or IP erased? How often? In a single processor unit or with separate desktop processor and erasure units - it is erased by exposure to an intense light to release any remaining trapped electrons; daily
What is spatial resolution? The degree of geometric sharpness or accuracy of recorded detail of the structure that you are radiographically imaging.
What is an anatomical menu? This is what is selected by body part, by the radiographer, when the imaging plate is loaded into the reading unit
What is an S value, what are the parameters, and what manufacturer utilizes an S value? Sensitivity number, 150-250, Fuji system
Which manufacturer utilizes an exposure index for processing? What are the parameters? Kodak System, 1800-2200
What is a histogram? a graphical representation or diagram that is generated by dividing a scanned area into pixels and determining the signal intensity for each pixel.
When comparing a digital system to a film/screen system, what are the advantages of digital radiography over film/screen? Wide dynamic range, increased latitude, and the ability to use windowing and leveling.
When comparing a digital system to a film/screen system, what are some potential disadvantages utilizing digital radiography? Radiation safety and over exposure
What is ALARA? As Low As Reasonable Achievable: which includes avoiding any exposure to human tissue that will not be viewed during the diagnostic process.
What is the difference between direct and indirect acquisition when it comes to digital radiography? Direct-directly convert incoming x-ray photons to an electronic signal; Indirect-use a two-part process involving a scintillator and photodetector.
What is latitude and how does latitude compare between a film/screen system and a digital system? The range of exposures that will produce densities within the diagnostic range. No loses of the visibilities of structures that posses widely different densities.
Grid use and CR radiography Grid use in CR occurs more often due to the sensitivity of the imaging plate to scatter.
What is data clipping? Where the CR system does not send all the data acquired by the imange receptor to the post-acquisition system because the quanity of data is far greater than the display system can provide for viewing.
How does a H&D curve differ between film/screen and digital radiography? Digital response is linear.
What is quantum mottle? How do you adjust your technical factors to correct quantum mottle? A lack of sufficient incoming data to process an image:AKA quantum noise; Use adequate MAS-meaning you need to use a high enough MAS setting to compensate for this.
What is DICOM? The Digital Imaging and Communications in Medicine standard is a system of computer software standards that permit a wide range of digital imaging programs to understand one another
Scintillators emit light _ , which can reduce spatial resolution. Isotropically
Fuji systems are _ proportional and Kodak systems are_ proportional Inversely; Directly
Created by: moore171@cox.net