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Operator Manual
8
of 34
SPR2-310.620.30.02.02
Technical Data
Dose rate at the image intensifier input
0
The dose rate is factory-set between 0.11 µGy/s and 0.44 µGy/s depending on
the I.I. format, measured behind the scattered radiation grid at the I.I. input.
Using a test phantom, the dose rate was set in a kV range between 70 kV
and 80 kV. The iris diaphragm is maximally opened for this.
Deviation of the dose rate value from the set values at the
image intensifier input
0
Depending on the examined object, different fluoroscopy data (kV, mA) are set.
The sensitivity of the image intensifier is influenced by beam quality (kV).
As a consequence, different dose rates may result at the I.I. input screen for the
same luminance at the I.I. output screen.
When examining a patient in fluoroscopy mode, additional scatter radiation val-
ues are produced in comparison to the phantom values, affecting the dose rate
at the image intensifier input.
Deviation calculation Using K as a correction value, (refer to diagram), the approximate deviation value
from the set dose rate can be calculated.
Calculation example: With 70 kV the correction value is 1.4. That is, if the set dose
rate value is 0.22
µ
Gy/s, the actual value is approx. 0.22
µ
Gy/s x 1.4 = 0.308
µ
Gy/s.
Setting the dose rate
value
If desired, the preferential position for the dose rate can be reprogrammed.
2,5
2
1,4
1,0
50 60
70 80 90 100
110 120 130
kV
K