Aligning The Light Field To The Radiation Field; Operating Sequence; Adjustment And Evaluation - Siemens MULTIMOBIL 2.5 Service Manual

Service Manual
Maintenance Instructions
8.8

Aligning the light field to the radiation field

8.8.1 Operating Sequence

Load a 24 Cm x 30 cm or 10" x12 " cassette
with film and place it on a table or base.
Using a tape measure, set a vertical SID of
100cm or 40" to the upper edge of the
cassette as shown.
Using slide flaps set a format of 18 cm x 24
cm or 8"x 10".
Switch on the Collimator Lamp and align the
cassette.
Attach radio-opaque markings to the
cassette. Attach a washer as lateral marking.
Trigger an exposure and develop the film .
Using a waterproof felt pen, write the following
data on the developed film
- set SID
-film size
-radiation field size

8.8.2 Adjustment and Evaluation

Measure the deviations between light field
edges and radiation field edges on all four sides
(X1,X2,Y1,Y2) as shown.
Y1
Determine the total deviations in the X and Y
X1
direction ( ignore the +/- signs).
Both, length deviation (ΣY) and width deviation
X2
(ΣX) must be ≤ 2.0 cm.
If the deviation is higher, loosen the 4 screws.
slightly and move the collimator accordingly as
shown. Then tighten the screws at the collimator
again.
Y2
Repeat the check and, if necessary, adjust the
collimator again until the deviation between the
light field and the radiation field is within the
tolerance (≤ 2 cm).
Siemens Ltd. Med India Version 6.0
8-6
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