Reproducibility, Linearity, & HVL Testing
CPI Canada Inc
Page 6 Rev. A X-Ray Generator Service Manual Supplement 740917-00
3.0 REPRODUCIBILITY
(Cont)
3 point = 80% of maximum kV, 250 ms, mA to give 100 - 500
µ
R (1 - 5
µ
Gy) dose.
2 point = 80% of maximum kV, mAs to give 100 - 500
µ
R (1 - 5
µ
Gy) dose.
MAS = __________
EXP No.
DOSE (mR)
DIFFERENCE
DIFFERENCE
2
1
2
3
4
5
mR =
________
Calculate each of the differences
ie: DIFF
1
= mR
1
- mR.
Repeat for each remaining mR
value.
Square each difference. Then
calculate the sum of the difference
2
.
Sum of difference
2
= _________
Calculate standard deviation (S) using formula at beginning of this section: S = __________
Calculate reproducibility = S = _________ (not to exceed 0.045)
mR
Table 4: Reproducibility
EXAMPLE
mAs = _20_
EXP No.
DOSE (mR)
DIFFERENCE
DIFFERENCE
2
1 249.0
4.4
19.36
2 245.0
0.4
0.16
3 244.0
0.6
0.36
4 242.0
2.6
6.76
5 243.0
1.6
2.56
mR =
_244.6_
Calculate each of the differences
ie: DIFF
1
= mR
1
- mR.
Repeat for each remaining mR
value.
Square each difference. Then
calculate the sum of the difference
2
.
Sum of difference
2
= _29.2_
Calculate standard deviation (s) using formula at beginning of this section: S = _2.70_
Calculate reproducibility = S = _0.011_ (not to exceed 0.045)
mR
Table 5: Reproducibility
