Equipment Flashcards
What does the conductive layer of a CR cassette do?
Reduced static electricity
What layer of a CR cassette “traps” electrons during exposure?
Phosphor layer
What are the layers of a CR cassette?
Protective Phosphor Reflective Conductive Support Light shielded Backing layer Bar code label
What are the advantages of CR?
lower pt dose & repeat rate Higher contrast resolution no dark room costs enhancement of images electronic storage PACS
What is the main difference b/w indirect DR and direct DR?
Indirect ~ x-rays converted to light, light to electronic signal
Direct ~ X-rays converted to electronic signal
What is high pass filtering & when is it used?
“edge enhancement”
Fewer pixels used to create signal average
used to enhance large structures like organs
What is low pass filtering & when is it used?
“smoothing”
averages each pixel’s frequency w/ surrounding pixels values ~ removes high frequency noise
used for viewing small objects
What are the components in an II?
Input Phosphor Photocathode Elctrostatic focusing lenses Anode Output phosphor
What is a CCD & what is it used for?
Charge couple device
Used in fluoro
converts light into electronic signal
What type of grid cutoff has occured when there is cutoff across entire image, unexposed, light image?
Off level
Off center
What is appearance when the grid is off focus?
toward edge of image
Is there increased or decreased spatial resolution in DR?
Decreased
What are advantages of PACS?
Prompt access to images w/in the medical center & especially at remote locations
Ability for more than one medical professional to simultaneously view the same age
reduced loss of clinical images
reduced personnel (file clerks)
What is the max variability for reproducibity of exposure?
5 %
What is the max percentage of variability for radiation output (kVp)?
10%
