Zeiss INTRABEAM, Инструкция по эксплуатации

Страница: 53 / 82

Version 6.2
G-30-1767-en
Page 53
INTRABEAM Water Phantom Operation
Measuring the depth dose curve with spherical applicator
Using the depth dose curve, a characteristic curve from the dose rate [Gy/min]
in relation to the penetration depth [mm] of the respective XRS 4 is measured
at 40 kV and at 50 kV.
As a rule, the depth dose of the X-ray probe is initially recorded without an
applicator. It therefore can be assumed that there will be no need to com-
pletely reposition the probe tip when measuring the depth dose curve with a
spherical applicator.
Inserting the spherical applicator in the INTRABEAM Water Phantom
Exact positioning of the applicator (with the probe tip) is a precondition for
accurate and meaningful measuring results.
• Do not adjust the positioning unit in the X and Y axes.
• Unless this has already been done:Note down the previously determined
value of Z
1
[mm], see page 41.
• Release the locking lever on the adjusting knob for the Z axis.
• Place the positioning unit all the way up in the Z axis.
• Pull the two covers of the water tank apart sideways over approx. 1/3 of
their surface.
• Loosen the screws for fixing the XRS mount in the rotary feedthrough.
• Remove the XRS mount.
NOTE Contamination of the contact surfaces between the adapter plate and the ro-
tary feedthrough may result in uneven seating of the XRS 4, thus causing sig-
nificant deviations of the measured depth dose curve from the calibration
file.
•
Make sure that these contact surfaces are always clean.