Correction Of The Measured Optical Density (O.d.); Procedure; Normal Developing Conditions - Siemens MAMMOMAT 1000 Nova Installation And Start-Up Instructions Manual
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Calibrating and adjusting the AEC
Correction of the measured Optical Density (O.D.)
Due to variations in the developing conditions (see also section "Normal developing condi-
tions") the measured optical density of one specific image might not correspond to the
adjusted optical density (sensitivity setting). Therefore the optical density has to be cor-
rected for the variations in the developing conditions.
NOTE
OD
m
OD
corr
OD
strip
OD
strip_ref
Procedure
•
- For grid/no grid: cover the area far from the chestwall side with metal plate (part no.
65 52 728).
- For magnification: place metal plate (part no. 65 61 026)
as close as possible to the cassette to prevent scattered radiation and cover the area far
from the chestwall side.
•
Develop all films with a sensitometer strip on the part that was covered by the metal plate
(part no. 65 52 728 or 65 61 062).
•
Measure the optical density in two places: OD
the sensitometer strip).
•
Calculate the corrected O.D. as follows:
OD
= OD
corr
Normal developing conditions
When measuring the O.D., it is essential that the working conditions are as close to nor-
mal as possible. There are several parameters that may effect the results:
•
Temperature of developer and dryer
•
Feeding and developing speed
•
Replenishing speed of developer and fixer (liquids)
If possible, develop the film among other films when the developer is warm and stabilized.
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This correction has to be made for
1. fine setting of sensitivity correction
2. setting of sensitivity
3. final testing.
The measured optical density in the mea-
suring point, see Fig. 2.
The corrected optical density.
The O.D. in the step of the sensitometer
strip
to the O.D. of the measuring
closest
point.
The measured OD
under normal developing conditions shall
be used as OD
strip_ref
+ (OD
- OD
m
strip_ref
strip
Register 3
SPB7-230.033.11
Rev. 06
on first film exposed
strip
.
(as described in Fig. 2) and OD
m
)
05.06
the magnification table
inside
Page 7 of 22
M1000/3000 Nova
CS PS SP
Installation and Start-Up
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