Quantum ODYSSEY HF Series, Service Manual

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Appendix B Calibration (DiRex System)
Revision W HF Series X-ray Generators - Service Manual
B-54
Quantum Medical Imaging, LLC
i. Set the "Target Level" to the desired level (e.g., "1.30" as
shown in Figure 3-27). To do so, press the Target Level value
button (located directly below "Target Level" label), use the
keypad to input the desired value, then press Enter.
Do not
change the Target Level setting at any time during this proce-
dure.
ii. Place 5 CM of acrylic in the X-ray beam.
iii. Take an exposure at the setting indicated on the AEC Optical
Density Calibration Screen (i.e., 50 kVp, 200L mA, normal
density).
iv. Process the CR Film Plate to determine density level (referred
to as the "LGM" value).
v. If the LGM value is within acceptable range of the Target
Level as defined by the CR Film Plate manufacturer, press the
Next button to save the setting and proceed to AEC KV Cali-
bration.
vi. If LGM value is too low, press the AEC Base value button
(located directly below "AEC Base" label). Increase the AEC
Base value, press Enter, then repeat exposure. If density is
too high, press the AEC Base value button, decrease the AEC
Base value, then repeat exposure. Continue until the mea-
sured LGM value equals the Target Level setting to within CR
System manufacturer’s specification.
4. Press the Next button to advance to AEC KV Calibration.
IMPORTANT! To ensure AEC density is correctly cali-
brated to the desired "target" density setting, either
the AEC Base value must be adjusted to obtain the
target density level (verified using the processed CR
Film Plate) or the target density level shown on the
AEC Optical Density Calibration Screen must be set to
the actual LGM value obtained from the processed CR
Film. For example, the calibrator would like the sys-
tem AEC density to be "2.10". The calibrator must
adjust the "AEC Base" value until the actual mea-
sured LGM value of the CR Film Plate is 2.10. How-
ever, if the actual measured LGM value of the CR Film
Plate is 2.20 and you decide not to continue to adjust
the AEC Base to achieve exactly 2.10 density, then
change the Target Level setting shown on the AEC
Optical Density Calibration Screen to "2.20".