CPI Canada Inc.
AEC Calibration
3D
Millenia / Indico 100 Series Service Manual Ch # 740904-06 Rev. D
Page 3D-41
3D.10.0 AEC CALIBRATION (WALL BUCKY) Cont
Grid Absorption
The following information may aid in selecting a grid and/or estimating doses in front of the bucky if required: The
percentages listed are approximate.
∗
A 10:1 ratio 60 in (150 cm) focused grid will exhibit the following absorption when measured 5 in (13 cm)
from center:
At 72 in (180 cm) absorption = 18%
At
40
in
(100
cm)
absorption
=
40%
∗
A 12:1 ratio 60 in (150 cm) focused grid will exhibit the following absorption when measured 5 in (13 cm)
from center:
At 72 in (180 cm) absorption = 20%
At 40 in (100 cm) absorption = 50%
∗
A 10:1 ratio 72 in (180 cm) focused grid will exhibit the following absorption when measured 5 in (13 cm)
from center:
At 40 in (100 cm) absorption = 65%
∗
A 12:1 ratio 72 in (180 cm) focused grid will exhibit the following absorption when measured 5 in (13 cm)
from center:
At 40 in (100 cm) absorption = 75%
∗
A 10:1 ratio 40 in (100 cm) focused grid will exhibit the following absorption when measured 5 in (13 cm)
from center:
At 72 in (180 cm) absorption = 65%
∗
A 12:1 ratio 40 in (100 cm) focused grid will exhibit the following absorption when measured 5 in (13 cm)
from center:
At 72 in (180 cm) absorption = 75%
NOTE:
BREAKPOINT CALIBRATIONS MAY HAVE BEEN DONE FOR ALL THREE FILM SCREEN
COMBINATIONS DURING TABLE BUCKY AEC CALIBRATION. IF SO, THE REMAINING
IMAGE RECEPTORS MUST USE THE CALIBRATION CURVES PREVIOUSLY ESTABLISHED
FOR THOSE FILM SCREENS.
IF AN UNUSED FILM SCREEN COMBINATION IS AVAILABLE FOR WALL BUCKY
USE, IT IS SUGGESTED THAT TWO RECEPTOR SELECTOR BUTTONS ON THE CONSOLE
BE ASSIGNED TO SELECT THE WALL BUCKY. THE FIRST WALL BUCKY SELECTOR
SHOULD BE USED FOR 40
″″″″
(100 CM) SID’S WITH THE APPROPRIATE PREVIOUSLY
CALIBRATED FILM SCREEN. THE SECOND WALL BUCKY SELECTOR SHOULD THEN BE
USED WITH THE PREVIOUSLY UNCALIBRATED FILM SCREEN AT 72
″″″″
(180 CM) SID’S.
THIS METHOD WILL ALLOW THE GRID TO BE OPTIMIZED FOR EACH SID, AS A
SEPARATE DEDICATED FILM SCREEN WITH ITS OWN CALIBRATION CURVE CAN BE
ASSIGNED TO THE 72
″″″″
(180CM) SID.
