1. PHOTOSTIMULABLE-PHOSPHOR PLATE (PSP)
RESPONSES IN COMPUTED RADIOGRAPHY AT
EXPOSURE FACTOR ASCENT RELATED TO TUBE
VOLTAGE ACCURACY & OUTPUT LINEARITY OF
X-RAY MACHINE
DWI ADHIANTO
24040112150010
MEDICAL PHYSICS TRANSFER PROGRAM
SCIENCE AND MATH FACULTY
DIPONEGORO UNIVERSITY
SEMARANG
2014

2. INTRODUCTION
 Accuracy of control panel-radiation output
become one of aim for quality control in
radiology services.
 General using of Computed Radiography in
Indonesia .
 Linear response of imaging plate to x-ray
intensities

3. Tube voltage accuracy and linearity of output
from x-ray machine use photostimulable-
phosphor plate responses which is basic of
Computed Radiography technology
PROBLEM FORMULATION

4. AIM OF RESEARCH
Understanding influence of the gradual ascent
of exposure factor in x-ray machine to
photostimulablephosphor plate responses
related to tube voltage accuracy and linearity
of output x-ray machine.

5. RESEARCH PROFIT
Giving an alternative way for the Hospital that held
Computed Radiography System to perform
compliance test by using imaging plate responses.

6. COMPUTED RADIOGRAPHY

7. BASIC OF RESEARCH

8. COMPUTED RADIOGRAPHY RESPONSES
1. EXPOSURE INDEX
2. DEVIATION INDEX
3. IEC STANDARD 62494-1
4. MEAN GRAY VALUE

9. RESEARCH INSTRUMENTATION
&MATERIAL
• RADIODIAGNOSTIC MACHINE
• COMPUTED RADIOGRAPHY
(CARESTREAM)
• X-RAYANALYZER PIRANHA
• ALLUMINIUM STEPWEDGE

10. RESEARCH METHODE
Compliance Test :
1. Tube Voltage Accuracy
2. Tube Current Linearity
3. X-Ray Reproducibility
Examination
Table
X-ray Tube
Detector
SID

11. GETTING PRIMARY DATA
CR
Positioning
CR Expose CR Reading
Exposure
indicator
Value entry
Analyzing
digital
image
ImageJ1.46r
X-rar Tube
STEPWEDGE
SID
Imaging
Plate
Examination
table

12. RESULT OF THE RESEARCH
COMPLIANCE TEST RESULT:
Tube Voltage Accuracy:
Inaccuracy maximum is 1,4 % in 90 kVp
Tube Current Linearity:
Maximum Difference in mGy/mAs at 0,3 %
X-Ray Reproducibility:
Coefficient variation of voltage reproducibility is 0,01
& Exposure reproducibility is 0,01

13. Relation of linear ascent in tube voltage (kVp) with steady
tube current-exposure time (mAs) to Exposure Index
y = 1712.ln(x) - 5669.
R² = 0.979
y = 1785.ln(x) - 5720.
R² = 0.983
y = 1868.ln(x) - 5815.
R² = 0.967
y = 1870.ln(x) - 5574.
R² = 0.971
y = 1872.ln(x) - 5300.
R² = 0.962
y = 1926.ln(x) - 5275
R² = 0.959
0
500
1000
1500
2000
2500
3000
3500
40 50 60 70 80 90 100
ExposureIndex
Tube Voltage (kVp)
0,5 mAs
1 mAs
2 mAs
4 mAs
8 mAs
16 mAs

14. y = 19.06x - 933.8
R² = 0.952
y = 39.41x - 1949.
R² = 0.962
y = 78.21x - 3820.
R² = 0.954
y = 149.1x - 7341.
R² = 0.940
y = 320.8x - 15791
R² = 0.952
y = 633.6x - 31140
R² = 0.959
0
5000
10000
15000
20000
25000
30000
40 50 60 70 80 90 100
IECStandard
Tube Voltage (kVp)
0,5 mAs
1 mAs
2 mAs
4 mAs
8 mAs
16 mAs
Relation of linear ascent in tube voltage (kVp) with steady
tube current-exposure time (mAs) to IEC Standard

15. Relation of linear ascent in tube voltage (kVp) with steady
tube current-exposure time (mAs) to Deviation Index
y = 18.19ln(x) - 78.09
R² = 0.980
y = 18.02ln(x) - 74.29
R² = 0.991
y = 18.02ln(x) - 71.19
R² = 0.979
y = 18.42ln(x) - 70.04
R² = 0.987
y = 18.38ln(x) - 66.67
R² = 0.982
y = 18.15ln(x) - 62.74
R² = 0.986
-10
-5
0
5
10
15
20
25
40 50 60 70 80 90 100
Deviationindex
Tube Voltage (kVp)
0,5 mAs
1 mAs
2 mAs
4 mAs
8 mAs
16 mAs

16. Relation of linear ascent in tube voltage (kVp) with steady
tube current-exposure time (mAs) to Mean Gray value
y = 909.5ln(x) - 2370.
R² = 0.905
y = 672.0ln(x) - 1224.
R² = 0.846
y = 442.2ln(x) - 103.3
R² = 0.696
y = 625.2ln(x) - 794.4
R² = 0.738
y = 461.0ln(x) + 8.540
R² = 0.829y = 393.6ln(x) + 362.5
R² = 0.405
0
1000
2000
3000
40 50 60 70 80 90 100
MeanGrayValue
Tube Voltage (kVp)
0,5 mAs
1 mAs
2 mAs
4 mAs
8 mAs
16 mAs

17. Relation of linear ascent in tube current-exposure time (mAs) with steady
tube voltage (kVp) to Exposure Index
y = 344.3ln(x) + 1198.
R² = 0.998
y = 387.3ln(x) + 1641.
R² = 0.999
y = 381.0ln(x) + 1940.
R² = 0.999
y = 376.6ln(x) + 2076
R² = 0.999
y = 387.7ln(x) + 2269.
R² = 0.999
0
1000
2000
3000
4000
0 5 10 15 20
ExposureIndex
Current-Exposure Time (mAs)
50 kVp
60 kVp
70 kVp
80 kVp
90 kVp

18. Relation of linear ascent in tube current-exposure time (mAs) with steady
tube voltage (kVp) to IEC Standard
y = 141.5x - 11.36
R² = 0.999
y = 400.6x - 25.48
R² = 0.999
y = 726.5x + 23.91
R² = 0.999
y = 1090.x - 157.5
R² = 0.999
y = 1785.x - 49.45
R² = 0.999
0
5000
10000
15000
20000
25000
30000
0 5 10 15 20
IECStandard
Current-Exposure Time (mAs)
50 kVp
60 kVp
70 kVp
80 kVp
90 kVp

19. Relation of linear ascent in tube current-exposure time (mAs) with steady
tube voltage (kVp) to Deviation Index
y = 4.330ln(x) - 4.352
R² = 0.999
y = 4.460ln(x) - 0.099
R² = 0.999
y = 4.279ln(x) + 2.939
R² = 0.999
y = 4.422ln(x) + 4.342
R² = 0.999
y = 4.387ln(x) + 6.588
R² = 0.999
-10
-5
0
5
10
15
20
25
0 5 10 15 20
DeviationIndex
Current-Exposure Time (mAs)
50 kVp
60 kVp
70 kVp
80 kVp
90 kVp

20. Relation of linear ascent in tube current-exposure time (mAs) with steady
tube voltage (kVp) to Mean Gray Value
y = 215.4ln(x) + 1417.
R² = 0.971
y = 153.9ln(x) + 1525.
R² = 0.882y = 175.2ln(x) + 1562
R² = 0.988
y = 91.50ln(x) + 1730.
R² = 0.860
y = 160.0ln(x) + 1846.
R² = 0.959
0
500
1000
1500
2000
2500
0 2 4 6 8 10 12 14 16 18
MeanGrayValue
Current-Exposure Time (mAs)
50 kVp
60 kVp
70 kVp
80 kVp
90 kVp

21. Coefficient of Linearity |X1 – X2| ≤ 0.1 (X1 + X2)
Result of Measuring of mAs linearity by Piranha analyzer
achieved maximum Coefficient of Linearity amount
0,0031
Result of Calculating IEC Standard/mAs achieved Coefficient
of Linearity amount 0,005-0,061
y = 0.051x - 0.000
R² = 1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 5 10 15 20
Eksposur(mGy)
Arus tabung-Waktu penyinaran (mAs)

22. CONCLUSION
• Exposure indicator in CR that used in this
research is calibrated because it has linear
responses to the radiation output compare to
result of compliance test with Piranha
Analyzer
• Linearity of mAs can be decided with a
calibrated imaging plate
• Deciding a coefficient of mAs linearity can
be done with IEC Standard/mAs data.

23. CONCLUSION
• Determining of tube voltage accuracy with an
Exposure indicator can be done.
• Mean gray value is able to be an indicator of
mAs linearity because has a coefficient of
correlation more than 0,94.

24. SUGESTION
• Doing research to density of film print out in
same condition as the research.
• Doing research for the others CR vendor.

25. THANKS FOR THE ATTENTION