Key Terms Flashcards
(48 cards)
1) What is the ability Of the system to record adjacent small structures, equipment related
2) and is measured in what
1) spatial resolution
2) line pairs per mm lp/mm
What is the smallest area depicted in an image that is two dimensional square that contains discreet gray shade?
Pixel
As pixel size increases spatial resolution (increases/decreases)
Decreases
In spatial resolution when referring to pixels what is measured center to center?
Pixel pitch
1) As pixel pitch increases spatial resolution (increases/decreases)
2) Measured in…
1) decreases
2) microns (um)
1) When referring to spatial resolution referring to pixels what is the number of pixels per millimeter?
2) It is determined by the pixel _____ and pixel _____
1) pixel density
2) pixel size and pixel pitch
As pixel size decreases pixel density (increases/decreases)
Increases
Pediatric patients are more sensitive to radiation exposure by how much
5%
For part thickness a general rule part measuring greater than ____ centimeters requires the use of grid to offset the production of secondary and scatter radiation in the volume of the tissue as the x-ray beam passes through the tissue
10 cm or 4in
Casts:
What increase in KVP and mAs:
1) wet
2) dry
3) fiberglass
1) kvp-8-10% increase with 100% increase in mAs
2) kvp-5-7% increase with 50-60% increase in mAs
3) kvp- 3-4% increase with 25-30% increase in mAs
1) Quantum mottle may occur with AEC techniques if the required of _____ is too low?
2) how do you compensate for that?
1) mAs
2) decrease kvp and increase in mAs
1) Another term for anatomic alignment
2) What is key when referring to this
1) Limited positioning latitude
2) positioning!
When referring to receptor exposure control: (+1, -1)
1) A very thin patient or pediatrics a _______ receptor exposure control may be selected to help prevent ________
2) A very large patient a ______receptor exposure control may be selected to help prevent ________
1) -negative
- overexposure
2) -positive
- underexposure
Fixed KVP charts are also referred to as_______
Variable mAs chart
Variable KVP chart is also known as_______
Fixed mAs chart
The fixed KVP technique system is similar to the basic principle of _________
Photo timing
When referring to technique charts talking about variable KVP chart:
1) a ____ kV change It’s made for each centimeter in part thickness when operating at 80 kvp
2) a ___kV change Is made for each centimeter in part thickness when operating at or above 80 KVP
1) 2 kV
2) 3 kV
For geometric factors distortion:
1) Shape distortion are limited to…..
2) size distortion is limited to changes in….
1) shape- • angle of part • angle of IR • motion ~ elongation and foreshortening
2) size-
• OID
•SID
~ increase in OID = magnification increases (to compensate for increase OID, You increase SID)
What is the reduction in the size of the focus directed towards the image receptor versus the size of the actual area on the surface of the anode bombarded with electrons, is referred to as
Line focus principle
When referring to line focus principle which focal spot is larger than the other
Actual focal spot is always larger than effective focal spot
1) When referring to line focus principle the actual focal spot receives electrons from the ______
2) The effective focal spot or projected focal spot or useful focal spot receives electrons from the _____
1) cathode
2) anode
For effective focal spot as the angle of the Anode decreases, the effective focal spot (Increases/ decreases)
Decreases
1) What are the geometric factors?
1) All of these effect what?
1)
1) SID
2) OID
3) focal spot size
4) motion
5) angulation (of tube, body part, IR)
2) •recorded detail
• distortion (spatial resolution)
1) What is DEL?
2) What are the factors that affect it?
1) detector element
2) •size (smaller= better resolution)
• pitch ( center of detective element to center of other)
• full factor (the amt (area) of the DEL dedicated to radiation detection)
