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32551-IMG rev 6
5.2
A
LIGNMENT
In case of normal service or maintenance: All required alignments and
adjustments must be performed. See additional information about the
tests in Service Manual.
5.2.1
Recommended test equipment
– Calibrated Sensitometer, Densitometer, Thermometer
– Calibrated light intensity (lux) - meter
– Calibrated Oscilloscope
– Calibrated TRMS Digital Voltmeter (DVM)
– Calibrated kV-meter RTI, PMX-I/M or similar
– Calibrated radiation meter, MDH 1015/1515 with 10x5-6 ion
chamber or similar
– Calibrated Sensitometer, Densitometer + acrylic blocks and Film &
Cassette
5.2.2
Film processor evaluation
Test equipment requirement: Sensitometer, Densitometer, Thermometer.
1
Turn ON the film processor and let it warm up for at least half an
hour.
2
Run a clean-up film through the processor. This is just a piece of
regular film which will pick up dirt, etc., which would appear on your
film.
3
Obtain a sheet of the same film type to be used in your Alpha RT.
Select the color on the sensitometer that matches the color emitted
by the intensifying screen used.
4
Ensure that the emulsion side of the film is towards the light source
on the sensitometer. Expose two edges of the film, waiting 10
seconds between exposures, and run it through the processor.
5
Measure and record the optical density of step 1 for both edges of
the film. Record the average on both the film and in Table 2.6. Step 1
is the value of GROSS FOG (BASE FOG).
NOTE!
Always run the film through the processor in the same orientation and
location.
6
Find the step which has the density closest to 1.0. This step number is
the speed index. Record the average density and step number on the
film and in Table 2.6.
7
Go one step above and one step below the step of Speed Index.
Measure and record both densities.
8
Subtract the density value of the step below, from the density value
of the step above the speed index step. This result is the contrast
index. Record this on the film and in Table 5.5, Film processor
evaluation.
GE Healthcare
5 Setups, alignments and adjustments
&
ADJUSTMENT
63
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