Answers
2 possible explanations for why variance would be outside the accepted limit for
REPRODUCIBILITY - Answer-1. vaporization: if tungsten if vaporized and deposited on
the glass envelope of the tube, it will increase the attenuation of the beam which can
cause inaccurate exposures
2. timer failure: although the timer is consistent for all exposures, if there is a timer
failure, some exposures could have lasted longer or shorter than preselected. This
would result in different # of photons which ultimately results in inconsistent mR
3 recommendations to give to a first year student to reduce patient exposure? - Answer-
1. high kVp , low mAs
2. Filtration
3. Collimation
The exposure time accuracy should be checked:
A. monthly
B. bimonthly
C. semiannually
D. annually - Answer-d. annually
half wave rectified x-ray systems may contain:
A. zero diodes
B. one diode
C. two diodes
D. all of the above are possible - Answer-d. all of the above are possible
X-ray system mAs reciprocity has an acceptance parameter of
A. 2%
B. 5%
C. 10%
D. 15%
E. 20% - Answer-c. 10%
A synchronous spinning top is used on a three-phase unit with a time of 17ms.
Approximately how large of an arc shoudl appear if the timer circuit is accurate?
A. 3°
B. 6°
C. 17°
D. 36° - Answer-b. 6 degrees
time (s) = arc size / 360 degrees
, The difference in the waveform between the primary and secondary sides of the high
voltage transformer is:
A. frequency
B. velocity
C. amplitude
D. all of the above - Answer-C. amplitude
Voltage across the x-ray tube is most constant with _____.
A. high frequency generators
B. single phase, half wave
C. single phase, full wave
D. three phase, full wave - Answer-a. high frequency generators
The ____ circuit provides electrons for the x-ray tube current
A. rectifier
B. autotransformer
C. high voltage
D. filament - Answer-D. filament
The variability allowed for milliampere and time linearity is +/- ____%
A. 2
B. 5
C. 10
D. 20 - Answer-C. 10
The half value layer (HVL) of an x-ray beam is a measurement of beam ______.
A. intensity
B. quality
C. quantity
D. all of the above - Answer-b. quality
Which of the following should a quality control program for radiographic equipment
include:
1. visual inspection
2. environmental inspection
3. performance testing - Answer-all of the above
Half wave rectified, three phase units provide an x-ray beam at _______ pulses per
second
A. 1
B. 60
C. 120
D. 360 - Answer-B. 60