finals L8

Question 1

• covers generator, tube, cables, control panel, table, tube stand, and bucky.
• important to ensure that all equipment are working efficiently and accurate records are kept.

Answer 1

xray equipment

Question 2

• part of the electrical system of an x-ray machine which determines radiation output.
• inconsistency in radiation output will adversely influence the quality of the radiograph.
• The kV, mA, and exposure time must be consistent on all settings.

Answer 2

generator

Question 3

Many factors can influence radiation output. The ones to be considered are:

Answer 3

• Fluctuations in the main electrical supply
• Inconsistency or inaccuracies in kVp, mA, and exposure time.

Question 4

(cleaning of generator) Check that the equipment is earthed by ___ attached to the metal covers of the unit or by an earthly conductor carried in the main cable of a mobile unit

Answer 4

copper tape

Question 5

radiation output reproducibility test frequency

Answer 5

at the start of a QC program
yearly
as necessary

Question 6

radiation output reproducibility test equipment

Answer 6

• water phantom, consisting of a plastic flagon or bucket filled to a depth of 10 cm
• 2 sheets of lead rubber
• 1 loaded cassette

Question 7

(radiation output reproducibility test procedure) Cover three quarters of the cassette with lead rubber, ____, leaving an end section uncovered.

Answer 7

crosswise

Question 8

(radiation output reproducibility test procedure) Set a ___ SID.

Answer 8

100 cm

Question 9

(radiation output reproducibility test procedure)
Set an exposure that will produce a low density on the film (___). ___ and a ____ is suggested. It should be just possible to read newspaper print through the density produced (you may find it necessary to experiment before starting the test)

Answer 9

density of 1
80 kVp
low mAs

Question 10

(radiation output reproducibility test procedure)
Repeat this procedure for each of the remaining three sections. Making sure that you have identical conditions. When placing the lead rubber allow for a space of about ___ between each exposed area.

Answer 10

2 mm

Question 11

radiation output reproducibility test
If the densities are not the same

Answer 11

repeat the test at different times of the day. Mains fluctuations may be the problem.

Question 12

radiation output reproducibility test
If the densities remain inconsistent,

Answer 12

call the x-ray engineer

Question 13

radiation output reproducibility test
If the inconsistencies are unacceptable,

Answer 13

then stop using the unit until the fault has been corrected.

Question 14

constancy of radiation output at different ma settings frequency

Answer 14

start of a QC program
yearly
as necessary

Question 15

constancy of radiation output at different ma settings equipment

Answer 15

• step wedge or 10 cm water phantom (consisting of a plastic flagon or bucket filled)
• 2 sheets of lead rubber
• 1 loaded cassette

Question 16

constancy of radiation output at different ma settings
suggested exposures

Answer 16

Exposure 1: 80kV, 10mAs (50mA, 0.2s)
Exposure 2: 80kV, 10mAs (100mA, 0.1s)
Exposure 3: 80kV, 10mAs (200mA, 0.05s)

Question 17

If the out of step density in each test was the second exposure (100 mA), this indicates that the fault lies with the 100 mA setting.

Answer 17

80 kV 50 mAs (50 mA, 1.0 s)
80 kV 50 mAs (100 mA, 0.5 s)
80 kV 50 mAs (200 mA, 0.25 s)

Question 18

constancy of radiation output at different ma settings action
If the densities continue to be inconsistent

Answer 18

call an x-ray technician

Question 19

constancy of radiation output at different ma settings action
If the inconsistencies are minimal

Answer 19

continue to use the unit.

Question 20

constancy of radiation output at different ma settings action
If the inconsistencies are large

Answer 20

stop using the unit until the fault has been corrected.

Question 21

test for kvp accuracy frequency

Answer 21

When the equipment is first installed.
Yearly
As necessary

Question 22

test for kvp accuracy equipment

Answer 22

kVp meter
generator to be tested

Question 23

test for kvp accuracy
Place the sensor in the middle of the x-ray beam at an SID of

Answer 23

100 cm

Question 24

test for kvp accuracy
Take readings at 10 kVp intervals from ___ to the maximum kVp available.

Answer 24

50 kVp

Question 25

test for kvp accuracy The measured kVp must be within

Answer 25

+ or - 5 kVp or 5%.

Question 26

test for kvp accuracy If the measured kVps do not fall within the acceptable limits

Answer 26

call an xray engineer

Question 27

using a kvp test cassette frequency

Answer 27

When equipment is first installed. Yearly As necessary

Question 28

using a kvp test cassette equipment

Answer 28

- loaded kVp test cassette (Wisconsin peak kilovoltage test cassette) - 2 sheets of lead rubber - test cassette calibration graphs for each kVp level used - densitometer

Question 29

using a kvp test cassette Place the cassette on the tabletop, face up (side marked with kVp divisions) and long dimension of the cassette ___ to the anode-cathode axis

Answer 29

parallel

Question 30

using a kvp test cassette Collimate to the area of the cassette marked with the lowest kVp (__) Set a kVp of __

Answer 30

60 kVp

Question 31

using a kvp test cassette Set an mAs value that will give a density of approximately _ in the region of the dots

Answer 31

1

Question 32

using a kvp test cassette Expose each of the other section of the cassette (marked __, ___, ___ kVp) separately, using the appropriate kVp each time.

Answer 32

80 100 120

Question 33

using a kvp test cassette - On the radiograph the regions are identified as A (60 kVp), B (80 kVp), C (100 kVp), D (120 kVp). - Each kVp region contains two columns of dots. - The horizontal rows are numbered 1 to 10, 1 being at the darker end of the column. - One column of dots is of uniform density, in each region, and is called ____

Answer 33

reference column

Question 34

using a kvp test cassette darkest lightes

Answer 34

top at 120 kVp bottom 60 kVp

Question 35

using a kvp test cassette