RAD 140 FINAL EXAM REVIEW QUESTIONS AND ANSWERS

RAD 140 FINAL EXAM REVIEW QUESTIONS AND
ANSWERS

4 primary exposure factors - Answers - 1) kVp
2) mA
3) time
4) SID

relationship between kVp & IR exposure - Answers - directly proportional to the square
of kVp ratio

kVp affects what? - Answers - quality (penetrability) & quantity (number of photons) of x-
ray beam

*direct relationship:
higher kVp = higher quality/quantity

relationship between mA(s) & IR exposure




- Answers - directly proportional to IR exposure

mA determines what? - Answers - quantity; tube current

- controls the filament current which determines..
- the amount of thermionic emission, which determines...
- the amount of electrons driven towards the anode (tube current)

the quantity (intensity) of x-rays photons in the primary beam is determined by... [4] -
Answers - 1) kVp
2) voltage ripple
3) filtration
4) target material

, relationship between SID & IR exposure




- Answers - inversely proportional to the square ratio of SID

*governed by the inverse square law

relationship between grid ratio (GCF) & IR exposure - Answers - inversely related to grid
ratio (GCF)

relationship between beam restriction & IR exposure - Answers - inversely related to
beam restriction

exposure time - Answers - mAs = mA x time (s)

determines how long (s) the tube current flows (mA) from cathode to anode

(affects the quantity of x-rays produced)

equation to find mAs – Answers




- mAs = mA x time

*mA & time inversely proportional when trying to maintain mAs

voltage ripple - Answers - how much the voltage waveform varies during x-ray
production

3 basic types of x-ray generators & their voltage ripple variations - Answers - 1) single
phase - 100%

2) three phase
- 6 pulse: 13%