Zeiss INTRABEAM, Instructions For Use Manual

Page: 55 / 82

Version 6.2
G-30-1767-en
Page 55
INTRABEAM Water Phantom Operation
Positioning the spherical applicator with the XRS probe in the Z direction
• Calculate the distance of the applicator surface from the IC ionization
chamber:
r
iApp
= r
1
+ (Z
1
- Z
i
) - R
App
• Take care not to set the applicator too deeply (in the Z direction); there
would be a risk of collision between the applicator and the ionization
chamber holder.
• Lock the applicator in the Z position using the locking lever on the Z direc-
tion adjustment knob.
Measuring the depth dose curve, with spherical applicator and XRS probe
• Measure the depth dose curve of the XRS probe with the applicator at-
tached to it. For details of the depth dose curve measurement, please see
page 43.
• Evaluate the measurement, i.e. calculate the dose rate. For details, please
see page 50.
r
iApp
[mm] = Distance of the applicator surface from the IC ionization
chamber
r
1
[mm] = minimum distance of the probe tip from the IC ionization
chamber at which measurement is possible.
Z
1
[mm] = Z position value which you noted down
Z
i
[mm] = current Z position value
R
App
[mm] = radius of the applicator