Chapter 9
Page no. 1706
JC-CAL-A-046.fm
GE Healthcare
Senographe DS
Revision 1
Service Information and Procedures Class A 2385072-16-8EN
Job Card CAL A046 - Half-Value Layer Measurement
26. Press
Set Up
once on X-ray Console, select
Meas.D
,
enter the dose value E
0
in mGy (see Notice
above) and
press
Valid
.
27. Press
Set Up
twice, and select
0.2
.
28. Place 0.2 mm aluminum on top of the compression paddle; verify using the light beam that the alumi-
num sheet fully covers the ionization chamber field of view.
29. Take the calibration exposure (press the Exposure button
on the X-ray Console) with the 0.2 mm
aluminum sheet on the compression paddle, and read the dose value on the dosimeter.
30. Press
Set Up
once on X-ray Console, select
Meas.D
,
enter the dose value E
0
in mGy (see Notice
above) and
press
Valid
.
31. Press
Set Up
twice, and select
0.5
32. Place 0.5 mm aluminum on top of the paddle. Verify using light beam that the aluminum sheet fully
covers the ionization chamber field of view.
33. Take the calibration exposure (press the Exposure button
on the X-ray Console) with the 0.5 mm
aluminum sheet on the compression paddle, and read the dose value on the dosimeter.
34. Press
Set Up
once on X-ray Console, select
Meas.D
,
enter the dose value E
0
in mGy (see Notice
above) and
press
Valid
.
35. Press
Set Up
twice, and press
Calcul
.
36. Press
Set Up,
press
Param
, verify that the value is within the limits given below (
Acceptable Values
)
37. If the values are within limits, the Senographe stores HVL and Yield values.
If not, check the following and repeat the calibration:
•
Paddle is present,
•
Dosimeter is properly calibrated,
•
6M probe is correctly placed in the high position of the dosimeter holder tool
•
Tube tilt and format are correctly calibrated, and probe is in the 9x9 field of view
•
Generator kV and mA are properly calibrated.
If the calibration still fails, the tube must be replaced.
38. Repeat steps 24 through 37 for the other track/filter/focal spot combinations: SF/MoRh, SF/RhRh
techniques, and once all three combinations are complete, proceed to step 39.
39. Press
Set up
and perform a checksum (
SETUP/GENE/INSTAL/CKSUM/CKSUM
).
40. Press
Set up
and exit the Calibration Menu.
41. Remove the compression paddle.
8-1
Acceptable values:
The specification limits for HVL and Yield values measured under these conditions are:
Configuration
HVL (mm Al)
Yield (
μ
Gy/mAs)
MoMo 26kV
0.29 - 0.38
35 – 130
MoRh 28kV
0.31 - 0.47
35 – 130
RhRh 30kV
0.33 - 0.52
35 – 130
