RT 1303 REVIEW QUESTIONS
CHAPTER 9 X-RAY EMISSION
Define the terms listed below and describe which factors affect them?
Ans:
X-RAY QUANTITY
Synonyms: Intensity, MAS, amount of x-rays.
What affects influence the Quantity of x-rays produced?
Ans:
1.
Filament current in x-ray tube which then controls the tube current which is what
MA is.
MA selected on the control consol of the x-ray machine.
2.
Time selected on the control console of the x-ray machine (Remember MA x
TIME = MAS. This is a standard or manual technique. We are not talking about
photo timing or automatic technique.
3.
Inverse square law refers to the number of x-rays reaching the image receptor
and is determined by the number produced and the distance from the image
receptor.
What is MA & what controls it?
Ans:
MA is actually the number of electrons traveling from the cathode to the anode
when the high voltage has been energized. MA is controlled by the amount of
heat or amperage we put on the filament form the step down transformer, appx.
4-6 amps.
X-RAY QUALITY
Synonyms: Energy, KVP, penetration
Quality is a poor name, because it denotes that high KVP x-rays are good and
low KVP x-rays are bad. This is not the case at all, because we need to use the
correct KVP of x-rays based upon the type of body part we are radiographing.
Ex. Mammo requires low KV 26-9, while a CXR uses high KVP, 100-130 KVP, to
provide the needed contrast or differential absorption.
What factors influence the quality of x-rays produced?
Ans:
1.
Machine energy phase, ie. Single phase or 3 phase, or high frequency electrical
generator.
2.
KV selected on the control consol.
3.
Amount of inherent and added filtration.
(The average energy of the ex-ray beam is 1/3 to 2 of the applied KV as was
indicated earlier in this review.)
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