Ch.30 Flashcards
This screen usually includes erase cassette button, and options for entering patient and study data and for reviewing images.
Main Menu
This is a set default procedure code and generic setting for the equipment, only accessible to QC technologists or supervisors with a password.
Key Operator Functions
This screen is used to enter identification, demographics, and study information.
Study Data or Patient Data
This button sends the patients whole file to the PAC system for storage.
Submit Study
This is a screen used for windowing adjustments, presentation of histogram and exposure indicator.
Image Review Screen
Most systems allow for adjustments of iamge brightness contrast or magnification by cursor movement. Left to Right is what? Up does what?
Left to RIght- Usually increases brightness
Up- Usually increases contrast
Down- Usually decreases contrast
Extreme reduction of contrast by moving the cursor down can do what to the image?
Reverse the image making it black on white.
A magnifying glass icon is usually presented for doing what on the image.
Zooming in or out
From the image review screen, usually by touching the histogram, an image reprocessing screen can be accessed for what 3 things?
- Applying alternate algorithms
- Adding annotations, markers, arrows
- Applying a “black” mask (border), reversing or making other changes to the image.
This button dedicates the image to a particular study or series.
Assign or stamp view button
This can be used to assign a study by scanning the bar codes into the system using a laser reader.
CR cassette
This button sends the image with its current settings into a file in the PAC system.
Accept Image or Deliver
This sends the entire study into the PAC system for storage.
Accept (All) Images
This feature can be used to send an image directly to a printer without being saved into the PAC system.
Select Destination
The ___ of any imaging system expresses its sensitivity to radiation and is always inversely related to the amount of exposure required to produce an adequate signal at the image receptor.
Speed
What is the formula for speed?
1/exposure required
If twice the exposure is required what do you do to the speed?
Half the speed
What is the standard speed value that requires an exposure of 2mR to produce a density of 2.5
Speed value of 100
No set _____ exists by which speed can be gauged.
Density
Before the advent of digital imaging the most commonly used film/screen combinations in radiography had a speed of what?
400
Early CR readers were typically installed to operate at what speed?
200
This is the inherent speed of the photostimulable phosphor plate used as a CR image receptor.
200
When the processing speed of the CR or DR system is doubled the IR plate need to only receive how much exposure for the whole system to produce the proper image?
one-half
This speed assumes an average exposure of 2mR will penetrate through to the image receptor.
100
This speed assumes an average exposure of 1mR will reach the image receptor.
200
This speed assumes an average exposure of .5mR will reach the image receptor.
400
Although the inherent speed of a CR reader is 200, the speed of the reader can be what?
Adjusted
Nearly all modern CR and DR systems can be operated at a speed class of 300,350,400 with out the appearance of what in the image?
Substantial Mottle
Digital images taken at increased technique sometimes turn out what in appearance.
Lighter in appearance
This is a number used to provide feedback to the radiographer on the exposure level to the image receptor.
Exposure Index
Exposure indicators are not related to what?
Brightness Level
Insufficient techniques resulting in low exposure indicators can cause an unacceptable level of what in the image.
Mottle Noise
High exposure indicators reflect an unacceptable level of what to the patient?
Exposure
This should be utilized for adequate penetration and low dose to achieve exposure indicators within the correct recommended range.
High kVp. Low mAs
This is the counting average rather than the arithmetic average of the pixel values.
Median
By using median rather than mean averaging in calculating the exposure indicator, the indicator is less severely skewed by what processing error?
Segmentation