CPI Canada Inc
Reproducibility, Linearity, & HVL Testing
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X-Ray Generator Service Manual Supplement 740917-00 Rev. C
Page 3
2.0 EQUIPMENT
SETUP
1.
Place the radiation probe above the table approximately 25 cm (10”). Select an SID of
approximately 100 cm (40”).
2.
Place a lead diaphragm over the detector and adjust its height so that the X-ray beam covers the
detector but does not over radiate the sides of the probe. Refer to figure 1.
25 CM
(10"
)
10
0 CM (
4
0")
LEAD DIAPHRAGM
X-RAY
TUBE
RADIATION PROBE
Figure 1: Dose measurement setup
3.0 REPRODUCIBILITY
Calculate reproducibility as follows:
1.
Using kV and mA/ms or mAs values per tables 1 to 4, make a series of 5 exposures.
2.
Record each of the measured dose values, in mGy, in the appropriate table. Refer to step 3
before starting step 2.
To convert mR to mGy, divide the value in mR by 114.5. This will give the value in mGy.
(for example 114.5 mR = 1 mGy).
3.
Record the preselected mAs for each series of exposures in the header of each table. For 3 point
generators, this is the calculated mAs value where mAs = mA X time in seconds (example for
160 mA and 125 ms, mAs = 160 X 0.125 = 20 mAs).
