Check For Reproducibility - Siemens MOBILETT Plus HP Maintenance Instruction

Inspection and Maintenance
2.9

Check for reproducibility

Requirement:
•
The coefficient of fluctuation of the radiation dose may not be larger than 0.045 for any
combination of exposure parameters if the X-ray system is supplied with line voltage
as specified by Siemens.
NOTE
Required measurement devices:
- Dose meter
Procedure:
•
Wait until the system has reached thermal stability. A 15 minute warm-up time is re-
quired for the generator to be ready.
•
Release the specified number of exposures with the following exposure data:
X
- 85 kV, 1.0 mAs, 10 exposures.
•
Measure the dose for each exposure with the dose meter.
•
Reset the measurement display prior to each new measurement.
Calculations: Fluctuation coefficient C
•
The fluctuation coefficient C for a dose measurement sequence of 10 exposures is:
Fig. 23:
Where:
s =
=
x =
i
n =
The fluctuation coefficient C must be ≤ 0.045.
Setting
Siemens AG
Medical Solutions
The following test requires 10 sequential exposures, which must
be taken within one hour.
After each measurement, the exposure parameters should be set
to different values for a short time.
If the MOBILETT is equipped with a DAP measuring system, re-
move the DAP ionization chamber first.
standard deviation produced from the measurements
average measurement value of the sequence
i-th measurement value of the sequence
number of measurements in the measurement sequence
SPR8-220.101.04.03.02
07.05
Page 47 of 64
CS PS 24
47
MOBILETT Plus HP