Quiz 3 Flashcards
Why are there detector outlines on the upright bucky and not the table bucky?
the table top floats and doesn’t move with the bucky
How does AEC work?
it terminates the exposure when the IR receives the proper amount of radiation by measuring RR
Where is the AEC detector located?
between the grid and the IR
How can you determine if it is not a falling load generator?
there will be a mA displayed
How much higher are backup times?
1.5x - 2x
What are the detectors of AEC?
center call/detector lines up with the CR
selection from 1-3 detectors
select the detector under the area of interest
What are the detectors designed to get?
consistent exposure/intensity to the IR
less repeats/patient exposure
What is an Ion chamber?
full of gas atoms
X-rays ionize atoms
- free electrons
-strike a positive anode plate
- create current
IR gets a fixed amount of radiation in AEC regardless of?
kVp, mA, SID and patient thickness
when using AEC what factors are critical?
proper centering, proper positioning, sound knowledge of anatomy, proper collimation
Why do we have backup times (mAs)?
system failure
technologist error
to prevent extreme exposure to patient
to prevent tube overload
what is exposure adjustment or density detectors?
will extend or shorten the exposure
use them in high or low-scatter situations
Limitations of AEC?
anatomy that doesn’t completely cover the cell
peripheral anatomy
bad positioning or centering
radiopaque objects - i.e. hip replacement of barium swallow
does the use of filters affect AEC?
yes, it filters out low and high-energy photons
AEC over-exposure?
needed time < minimum response time
density left on plus setting
incorrect detector cell selection
radiopaque artifacts or appliances
electronic malfunction
