Ch. 20 Mobile Radiography Flashcards
Where were mobile x rays first used?
- World War I
- Marie Curie
- In the military, units were carried to field sites
A typical unit has controls for setting kVp and mAs, what are these typically ranges?
mAs range 0.04 to 320
kVp range 40 to 130
Power varies from ___ to ____
15 to 25 kilowatts
Do mobile machines have preset anatomic programs (APRs) similar to stationary units?
Yes! Some machines do
What three important technical factors must be clearly understood to perform optimum mobile examinations?
____ are also essential to optimum examinations.
1 Grid
2 Anode Heel Effect
3 Source to Image Distance (SID)
- Exposure Technique Charts
Optimum performance requires grid to be:
- Level
- Centered to CR
- Used at recommended focal spot or radius
What is grid cut off?
Use of a grid on unstable surface may cause absorption of primary beam = Grid Cut Off
Is proper placement of anode-cathode axis with the anatomy essential?
Yes!
What is the ideal SID for portable exams?
40 SID
What kind of grids do portable x ray units use?
Focused Grids
Why does it matter where anode vs cathode is placed?
Influences the intensity and distribution of x ray beam, impacting image quality and patient (PT) dose
Thicker side on Cathode
• Anode Heel Effect
Minimum safe distance for occupational expose?
6 feet (2 m)
What angle contains the least exposure to the patient and primary beam?
90 degree, right angle
What is the most effective radiation protection measure?
Distance!
Minimum source to skin distance:
12 inches (30 cm)
What does AID-ET stand for?
Acknowledge, Introduce, Duration, Explanation, Thank You
Portable unit placement for supine position:
Base of machine to middle of bed
For seated upright position where is the machine placed?
End of bed
For lateral and decubitus positions where is the x ray machine placement?
Parallel or perpendicular
how is collimation on portable images?
Not larger then the IR
Do you have to have a list of “To Do vs Completed with time exams?
Yes!
What are the two types of patients in isolation?
- Those who have contagious infections microorganisms
- Those who must be protected from exposure to infectious microorganisms (reverse isolation)
Do you wash hands before or after gloving?
Both!
You should check the CR and IR alignment to prevent what?
Distortion
