HF Series Generators
Calibration
CA-1036R2
27
2.6 AEC CALIBRATION
This section describes the adjustments needed to calibrate the AEC according
to the customer input. Therefore, AEC exposures will be made during the
calibration process in order to insure AEC functionality.
The Optical Density is controlled by the values stored in the respective memory
locations. These values are influenced by film speed, screen speed, dark room
procedures and customer requirements.
Use a homogeneous Phantom with enough density to produce an exposure of
100 ms, the AEC will be calibrated to produce a density of 1.0 (or the customer
preference Optical Density) at 70 kV, and then AEC tracking will be adjusted to
produce the same density at 55 kV, 90 kV and 110 k V.
For AEC calibration, use the same Film and Cassettes used by the
customer. AEC calibration must be performed
using the Medium
Film/Screen speed combination. The Medium Film/Screen speed
has to be double of the Slow and half of the Fast (e.g. 200--Slow,
400-- Medium, 800--Fast).
When using C R (Computer Radiography) or DR (Digital
Radiography) instead of measuring Optical Density:
-- measure the Image Gray level by using the needed software
tools inside each application (refer CR or DR documentation).
-- or measure the Dose level:
-- For CR, placing the Dosimeter as close as possible to the
Cassette and centered with the Central Area of the Ion Chamber.
-- For DR, placing the Dosimeter as close as possible to the
Panel, centered with the Central Area of the Ion Chamber and with
the Grid removed.
The following table indicates the Memory Locations related to AEC Calibration.
FUNCTION MEMORY LOCATION
AEC-1 CALIBRATION E04
AEC-1 TRACKING E08
AEC-2 CALIBRATION E09
AEC-2 TRACKING E10
AEC-3 CALIBRATION E20
AEC-4 CALIBRATION / PHOTOMULTIPLIER AEC CALIBRATION E23
AEC-3 and AEC-4 TRACKING (equal value for both) E24
AEC DENSITY SCALE E12
Note .
Note .
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