Final Exam Content

Question 1

What is AEC?

Answer 1

automatic exposure control
terminates the exposure when the IR receives the proper amount of radiation
Measures RR
IR should see the same amount of radiation no matter what

Question 2

What are the back up values in relation to the fixed?

Answer 2

usually 1.5x to 2x higher

Question 3

Can you use AEC for tabletop?

Answer 3

no, only in the bucky

Question 4

What are the detectors for AEC?

Answer 4

designed to get - consistent exposure/intensity to the IR - Less repeats/patient exposure
Ion chambers
Solid state detectors
photomultiplier tubes - not very common anymore

Question 5

What are Ion Chambers?`

Answer 5

full of gas atoms
X-rays ionize atoms - free electrons - strike a positive anode plate - create current
Larger or more dense objects absorb more radiation, therefore: less RR/sec and smaller current

Question 6

When using AEC what are important factors?

Answer 6

proper positioning
proper centering
sound knowledge of anatomy
proper collimation
understanding of procedure techniques