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What layer of your Imaging Phosphor is responsible for sending the light emitted in a forward direction for processing the image?
Reflective layer
What effect does the reflective layer have on resolution?
It reduces resolution
Which layer is also known as the active layer?
Phosphor layer
The active layer is usually made of what type of element?
Barium fluorohalide
Describe the order of events for standard PSP processing.
X-rays are taking, stimulating the phosphor. Place cassette in reader, phosphor film is taken out, hit with the laser light to receive the image, and converted from an analog to a digital image.
What is the reason that dye is added to the active layer?
Helps x-rays absorption, reduces patient exposure and better detail.
What layer of the IP is responsible for reducing and absorbing static electricity?
Electroconductive layer
Is there a potential for artifacts in the event that the environment is too dry?
yes, the artifact will look like deep dark cracks in the image.
whats the ideal range of humidity for when processing an image
40-60% humidity
What is the importance of correct orientation of the cassette when the patient is exposed?
If placed upside down, the patient information will be placed incorrectly and possibly be placed in the anatomy of interest
What is the importance of the phosphor center?
it's where your latent image is formed
Why can't a phosphor ever be completely cleared of stored electrons?
Impurities
Which material is used to prevent static buildup on the IP?
Felt material
What is the reason that aluminum is added to the PSP cassette?
To prevent scatter radiation
What color is the light released from the photodetector in PSP imaging?
Blue
The remnant x rays interact with the electrons in what crystals of the IP?
Barium fluorohalide
What information is contained in the barcode?
patient information (name, DOB, MRN) and date of exam
Why is the protective layer applied directly to the active layer?
To protect the PSP from damage during reading.
Fast scan refers to the movement of what part within the PSP reader?
Neon helium laser, zig zag pattern
What are the two most important functions of the ADC?
Controls contrast 2. convert analog to digital
What effect does reducing field size have on spatial resolution of the IP?
Decrease scatter and spatial resolution increased by more pixels in the anatomy of interest.
What is the reasons for a solid white line artifact parallel to film travel that is present on the entire dimension of the film?
Dust on the reader
The laser beam within the PSP reader is what color?
Red
What noble gas usually found in the laser?
Neon helium laser
What term is used to express the amount of detail in digital imaging?
Spatial resolution
What is the device responsible for amplifying the light given off by the IP?
Photo multiplier
Each square within the matrix is known as?
Pixel
How do pixels effect image resolution?
More pixels, better image resolution
What is the k-shell edge phosphor range for CR Imaging?
60-110 kVp, 30-50 keV
What technical factor primarily regulates the quantity of photons?
mAs
What effect does phosphor layer thickness have on resolution?
Thinner phosphor layers means better resolution
How often should IP's be completely erased?
Once a week
When would ghosting artifacts most likely be present?
abdomens, lumbar spine, laterals aka high exposures
What color of light is used to erase the IP?
White
primary erasure
used for primary beam photons.
secondary erasure
used for scatter radiation (when the plate is left in the room and exposed to scatter radiation)
What effect does digital imaging have on kVp range?
optimal kVp
What leads to the Moire effect in CR processing?
Grid lines aren't matched to laser scan direction
What is the recipe for better spatial resolution in PSP imaging?
Thin psp layer, slow translation speed, high pixel number, small pixel size
What type of dynamic range/latitude is present in digital imaging in comparison to film screen
Wide latitude
Why is grid use much more critical in PSP imaging in comparison to film/screen Radiography
Cleans up scatter on image receptor
High kVp is responsible for what type of histogram?
Higher exposure values
What is the LUT responsible for?
Contrast
List 3 ways Dose Creep is present in digital radiography
poor positioning/ ionization chamber 2. collimation 3. using the same technique for every patient
Why is collimation critical to digital imaging?
Patient dose, less collimation means more scatter
What is automatic rescaling?
The response to the stored image to that specific histogram
What does the window level control?
Black and whites (brightness)
What is shuttering?
Adding a black background to an image manly for aesthetic reasonings
What is the difference between the two types of CR reading systems?
Line Reader scans the plate one line at a time while point scan scans each point at a time.
When would a high-resolution phosphor be desired?
On hands, skulls, feet (extremities)
What is the danger of placing two separate images such as an AP and a lateral on one CR?
Can't have two different exposures on one CR because it can only read one image/ exposure
Double exposure
when the previous image wasn't processed so now there's two latent images being processed on one film.
Ghosting
leftover electrons from the previous processed image that shows up on the next image.
How does CR detail compare to film screen?
Not as detailed as film screen
How many Lp/mm are typical in CR imaging
Film screen had 10 lp/mm while CR has 2.55-5 lp/mm.
Why did the government reduce reimbursement for CR/PSP imaging?
Wants to move towards DR imaging + Obama care causes the need to process more images faster
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