finals L9

Question 1

ability of a radiographic unit to produce a constant radiation output for various combinations of mA and exposure time.

Answer 1

mAs linearity

Question 2

It is a principle that states that optical density on a radiograph is proportional only to the total energy imparted to the radiographic film.

Answer 2

mAs reciprocity

Question 3

for single-phase, full-wave rectified x-ray generators. test

Answer 3

Spinning Top Test

Question 4

• for testing a three-phase generator.
• measures the actual time of exposure which is compared to the selected time to verify accuracy.
• connected into the circuit to the primary voltage going to the step-up transformer.

Answer 4

Calibrated Oscilloscope

Question 5

• for both single-phase and three-phase x-ray generators.
• placed in primary x-ray beam, where pulses are counted and evaluated.

Answer 5

Pulsed Counter Device

Question 6

• test to check the accuracy of the xray unit timer.
• this test should only be carried out on a single phase unit.
• timers of three-phase and capacitor discharge units cannot be checked by this method.

Answer 6

exposure timer accuracy test

Question 7

EXPOSURE TIMER ACCURACY TEST frequency

Answer 7

At the start of a quality control program
Yearly
As necessary

Question 8

EXPOSURE TIMER ACCURACY TEST equipment

Answer 8

• Manually operated spinning top
  Top part - approximately 3 inch-round disk with a small hole near the edge.
  Circular pedestal - where the top part rests and rotates freely
• One loaded cassette
• Two sheets of lead rubber

Question 9

Cover three quarters of the cassette with
lead rubber, ____, leaving an end
section uncovered. EXPOSURE TIMER ACCURACY TEST

Answer 9

crosswise

Question 10

Set an exposure of __ kV, __ mA, and a
time of ___ sec. EXPOSURE TIMER ACCURACY TEST

Answer 10

70 kV, 100 mA, 0.1s

Question 11

If the number of spots on the images is different from the number expected, the timer may be ____. Repeat the test using different time settings. EXPOSURE TIMER ACCURACY TEST

Answer 11

inaccurate

Question 12

If the number of spots on all four images, on the film is the same, but different from the number expected, the fault would seem to be consistent. The unit can

Answer 12

still be used, but compensatory changes to exposures must be made.

Question 13

If the number of spots on the images is not the same, the fault would seem to be inconsistent. A decision must

Answer 13

then be made whether to use the unit or not.

Question 14

If the fault appears to be related to a specific time setting, the unit can

Answer 14

continue to be used, avoiding this time setting

Question 15

who to call EXPOSURE TIMER ACCURACY TEST

Answer 15

x-ray engineer

Question 16

Correct Number of Dots =

Answer 16

Exposure Time (s) x Pulses per Second

Question 17

Actual Exposure Time =

Answer 17

Arc Size / 360