Accurancy of kVp testTo check that

Accurancy of kVp test
To check that the generator is producing the kVp set on the control panel. This can be carried out by using a kVp meter or a kVp test cassette. One of the most widely used is the Winconsin peak kilovoltage test cassette.
Using a kVp meter :
a. Frequency of test
- When the equipment is first installed
- Yearly
- As necessary
b. Equipment required
- kVp meter
- Generator to be tested
c. Method
- Place the sensor in the middle of the x-ray beam at a FFD (SID) of 100 cm.
- Collimate to a standard area sufficient to cover the sensor.
- Take readings at 10 kVp intervals from 50 kVp to the maximum kVp available.
- Used a standard mA and time throughout.
- Repeat this procedure for each tube focus available.
d. Evaluation
- Compare each kVp reading with the appropriate kVp setting.
- The measured kVp must be within + or – 5 kVp or 5%.
e. Action
- If the measured kVp s do not fall within the acceptable limits, call an x-ray engineer.
Using a kVp test cassette :
a. Frequency of test
- When equipment is first installed
- Yearly
- As necessary
b. Equipment required
- Loaded kVp test cassette
- Two sheets of lead rubber, one 10 x 23 cm and the other 23 x 23 cm.
- Test cassette calibration graphs for each kVp level used.
- Densitometer
c. Method
- Place the cassette on the tabletop, face up (side marked wiht kVp divisions) and long dimension of the cassette parallel to the anode-cathode axis.
- Set a 100 cm FFD (SID).
- Collimate to the area of the cassette marked with the lowest kVp (60 kVp).
- Set a kVp of 60.
- Set a mAs value that will give a density of approximately 1 in the region of the dots (you may need to experiment).
- Shiels the remainder of the cassette with lead rubber.
- Make an exposure.
- Expose each of the other section of the cassette (marked 80, 100 and 120 kVp) separately, using the appropriate each time.
- The time setting should be adjusted each exposure, to maintain an optical density of 1 in the region of the dots each time. The mA remains the samefor each exposure.
- Remember to adjust the lead rubber each time.
- Process the film.
- Repeat this process at low, mid and high mAs settings.

Approximate mAs settings
kVp Single phase unit Three phase unit
60 500 400
80 75 40
100 15 10
120 12 8

Joel E Gray et al, Quality Control in Diagnostic Imaging
d. Evaluation
- 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 the reference column.
- The dots in the other column, in each region, will show a density gradient, darkest at the top (120 kVp region) and lightest at the bottom (60 kVp region).
- Look for density match between the two columns, in each region. This should be done with a densitometer.
- If an exact match is not found an average must be determined using the following method.
Example :
Step No. Optical density of step Optical density of reference
5 1,40 1,15
6 1,10 1,15

Match step = 6 + 1,40 – 1,15 = 5 + 0,25 = 5,83
1,40 – 1,10 0,30
- Whwn a match has been determined for each region, rafer to the calibration chart for the appropriate region (chart for each of the four kVp regions are supplied with the cassette).
- The chart will have two graphs on it, one for a single phase unit and one for a three phase unit.
- Using the appropriate graph, plot the match step level for each kVp region on the vertical axis, then the read off the corespondensing kVp s from the horizontal axis. These kVp s should, correspond to the kVp s used.
- The measured kVp must be within + or 5 kVp or 5%.
e. Action
- If the measured kVp s do not fall within the acepted limits, call an X-ray engineer.

Hasil (Inggris) 2:

Accurancy of kVp test
To check that the generator is producing the kVp set on the control panel. This can be Carried out by using a kVp meter or a kVp test cassette. One of the most Widely used is the peak kilovoltage Wisconsin test cassette.
Using a kVp meter:
a. Frequency of test
- When the equipment is first installed
- Yearly
- As Necessary
b. Equipment required
- kVp meter
- Generator to be tested
c. Method
- Place the sensor in the middle of the x-ray beam at a FFD (SID) of 100 cm.
- Collimate to a standard area sufficient to cover the sensor.
- Take readings at 10 kVp intervals from 50 kVp to the maximum kVp available.
- Used a standard mA and time throughout.
- Repeat this procedure for each tube focus available.
d. Evaluation
- Compare each kVp reading with the Appropriate kVp setting.
- The measured kVp must be within + or - 5 kVp or 5%.
E. Action
- If the measured kVp s do not fall within the acceptable limits, call an x-ray engineer.
Using a kVp test cassette:
a. Frequency of test
- When equipment is first installed
- Yearly
- As Necessary
b. Equipment required
- Loaded kVp test cassette
- Two sheets of lead rubber, one 10 x 23 cm and the other 23 x 23 cm.
- Test cassette calibration graphs for each kVp levels used.
- The densitometer
c. Method
- Place the cassette on the tabletop, face up (side marked wiht kVp divisions) and the long dimension of the cassette parallel to the anode-cathode axis.
- Set a 100 cm FFD (SID).
- Collimate to the area of the cassette marked with the Lowest kVp (60 kVp).
- Set a kVp of 60.
- Set a mAs value that will give a density of Approximately 1 in the region of the dots (you may need to experiment).
- Shiels the remainder of the cassette with lead rubber.
- Make an exposure.
- Expose each of the other section of the cassette (marked 80, 100 and 120 kVp) separately, using the Appropriate each time.
- The time setting should be adjusted each exposure, to maintain an optical density of 1 in the region of the dots each time. The mA remains the samefor each exposure.
- Remember to adjust the lead rubber each time.
- Process the movie.
- Repeat this process at low, mid and high mAs settings.

Approximate mAs settings
kVp Single phase units Three phase units
60.5004 million
80 75 40
100 15 10
120 12 8

Joel E Gray et al, Quality Control in Diagnostic Imaging
d. Evaluation
- 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 the reference column.
- The dots in the other column, in each region, will show a density gradient, darkest at the top (120 kVp region) and the lightest at the bottom (60 kVp region).
- Look for density match between the two columns, in each region. This should be done with a densitometer.
- If an exact match is not found, an average must be determined using the following method.
Example:
Step No. Optical density of optical density of reference step
5 1.40 1.15
6 1.10 1.15

Match step = 6 + 1.40 to 1.15 + 0.25 = 5 = 5.83
1.40 - 1, 10 0.30
- Whwn a match has been determined for each region, Rafer to the calibration chart for the Appropriate region (chart for each of the four kVp regions are supplied with the cassette).
- The chart will have two graphs on it, one for a single phase unit and one for a three phase units.
- Using the Appropriate graph, plot the match step kVp levels for each region on the vertical axis, then the read off the corespondensing kVp s from the horizontal axis. Reviews These should kVp s, Correspond to the kVp s used.
- The measured kVp must be within + or 5 kVp or 5%.
E. Action
- If the measured kVp s do not fall within the acepted limits, call an X-ray engineer.