Test 2 Flashcards
What is the film emulsion made of?
Silver halide crystals suspended in gelatin.
The purpose of using intensifying screens is to:
Reduce Patient Exposure
What are intensifying screens made of?
Rare earth crystals
You had a 200 speed film-screen system. The technique chart that is posted works well for the system. You purchase a new 600 speed film-screen imaging system. What will you need to do to all of mAs values on the existing technique chart?
Use 1/3 mAs
As film screen system speed increases, sharpness of detail:
Decreases
Which of these system speeds would you use for detailed extremity images?
100 Speed
Which of these would you choose if you specialize in pediatrics?
1200 Speed
Which of these would be the minimum speed used for spine imaging?
400 Speed
What is film latitude?
Range of error
How is film contrast related to film latitude?
Inversely
What type of safelight is safe for rare earth screen film combinations?
GBX
Safelight bulbs should be _____ or less.
15 Watts
Safelights should be placed at least _____ from the work surface in the darkroom.
4 Feet
Film should be stored at _____ relative humidity.
40-60%
Dirty screens cause these artifacts:
Sharp white dots
This should be used to clean intensifying screens:
Screen cleaner and gauze
Define LATENT image:
The invisible image on the film prior to processing.
What would happen if you use film that is out of date?
Fog
What is the function of fixer?
To clear and harden the emulsion
Why does the direction of film transport through the processor matter?
Chemical replenishment
What would the image look like it … processed with oxidized developer?
Too Light
how would the image look if the developer was too hot?
Too Dark
What is the function of developer?
To convert the latent into a manifest image.
What is the film BASE made of?
Polyester Plastic (mylar)
State the unit of absorbed dose in classical nomenclature:
RAD
State the unit absorbed dose in Systems International nomenclature.
Gray
100 RAD = ______ Gray
1
State the unit for occupational exposure in classical nomenclature.
REM
REM = RAD x ____
QF
What is the QF?
Quality Factor
What is the QF of x-ray?
1
In x-ray ____ R= _____ RAD= _____ REM
1-1-1
20 mRAD of x-ray exposure = ______ mREM
20
____ mREM = 1 REM
1000
_______ mREM = 1 REM
1,000
20 RAD of Alpha exposure = ____ REM
400
State the unit for occupational exposure in Systems International nomenclature.
Sievert
10 REM = ____ Sievert
1
Comparing annual radiation exposure to the population in the U.S., most exposure comes from this source:
Background: cosmis, terrestrial
This x-ray interaction with matter produces the whites in the image.
Photoelectric absorption
This x-ray interaction causes “fog” in an image.
Compton Scatter
This x-ray interaction occurs high kVp in the diagnostic range:
Compton Scatter (60-125 kVp)
This x-ray interaction decreases image contrast:
Compton Scatter
State the optimum range of kVp for spine imaging:
70-90 kVp
State the range of optimum kVp for extremity imaging:
50-60 kVp
Which of these will exhibit the least shape distortion?
PA lumbar spine
Which of these will exhibit the least size distortion?
AP Lumbar spine
When collimating from a 14x17 area to a 10x12 area:
Increase mAs 50%
An AP lumbar spine exam is properly exposed using 40 mAs, 73 kVp on a 14x17 film. If an 4x4 spot view of L-1 is required, what should the new exposure factors be?
60 mAs, 73 kVp
An image with no OID requires 20 mAs, what should the mAs be if there is a 6” OID?
30 mAs
