Siemens AG SPR2-310.842.01.07.02 ARCADIS Varic / Orbic
12.06 CS SD 24
Adjustments 27
Page 27 of 34
Medical Solutions
Accuracy check
X 1. Briefly release fluoro, select the <kV STOP> key and 70 kV with the kV + / - buttons on
the console.
X 2. Release fluoroscopy and note after approx. 10 seconds fluoro the dose rate from the
dose meter as “∆K
a
/∆t ext” and the displayed dose rate at the monitor as “∆K
a
/∆t int”
and stop fluoro.
3. Calculate the difference between the dose rate from the external dose meter multiplied
by Cx and the internal dose rate, displayed at the monitor, converted to µGy/s:
¹ Step 1: Calculate monitor value (∆K
a
/∆t) int from (mGy/min) to (µGy/s):
(∆K
a
/∆t int in mGy/min) x (16.66) = (∆K
a
/∆t int in µGy/s)
¹ Step 2: Multiply the external dose rate (∆K
a
/∆t ext) by factor (Cx):
(∆K
a
/∆t ext) x (Cx) = (∆K
a
/∆t ext _Cx)
¹ Step 3: Calculate the difference from (∆K
a
/∆t int) to (∆K
a
/∆t ext _Cx):
Difference = [(∆K
a
/∆t int) - (∆K
a
/∆t ext _Cx)] / (∆K
a
/∆t ext _Cx)
4. Evaluate the measurement; the maximum allowed difference is ± 0.35 (± 35%).
¹ For differences > + 0.35 and < - 0.35, an “air kerma dose matching” adjustment is
necessary.
5. Release the kV-stop key.
6. Repeat the “air kerma accuracy check” twice in full format with the following conditions:
¹ 1. Slot diaphragm = maximum open.
X-iris opening diameter = approx. 16 cm (measured on the monitor).
¹ 2. X-iris = maximum open.
Slot diaphragm opening diameter = approx. 16 cm (measured on the monitor).
Air kerma dose matching
1. Attach and center the centering cross on the I.I.
Fig. 8: diameter_x iris
Fig. 9: diamentor_slot_diaph
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