GE AMX-II Service Manual page 18

GENERAL ELECTRIC MEDICAL SYSTEMS AMX-ll X-RAY UNIT
1-981 OM A0654E
The yoke supporting the Tube Unit can be rotated 180 degrees about the horizontal axis in either direction
of the central position (x-ray port pointing straight downward). It can be positively retained in any inter-
mediate position by the YOKE ROTATION LOCK.
The TUBE UNIT ROTATION LOCK, located on the yoke clamp, locks or releases the Tube Unit for
rotation in the yoke clamps toward or away from the column. Two index lines, one on the Tube Unit and
one on the yoke clamp, may be used to place the central x-ray beam axis in the vertical plane.
The X-Ray Tube Unit is an HRT - O9N with a 1.0 mm focal spot.
The Sentry Manuai Collimator is used with the AMX-!| X-Ray Unit. The collimator limits patient rad-
iation exposure to a desired area at a given distance from the x-ray tube focal spot.
Minimum Source-to-Skin distance is limited to more than 30 centimeters by the tracks on the bottom of
the collimator for mounting the accessory Extension Cylinder.
Area of coverage is indicated by light from a GE Quartz!ine® high-intensity lamp. Distinct shadow cross
hairs, which indicate the field center, aid in accurate radiographic positioning.
The collimator has a fixed minimum filtration equivalent to 1.5mm of aluminum measured at 150 kvp, so
that a total filtration of 2.5mm of aluminum equivalent results from the tube-coilimator combination. By
inserting the 1mm and/or 2mm filter in the slot on the left side of the collimator, additional selective
filtration of 1, 2, or 3mm of aluminum equivalent may be obtained.
Dial numbers on the Calibrated Scale Drum, Illustration 1-5, are for 40, 48, 60, and 72 inch source-to-
image distances and standard film sizes of 5 through 17 inches (13 cm through 43 cm). To select the scale
for one of the four source-to-image distances, rotate the drum by turning the SCALE SELECTION KNOB
until the desired detent position is reached. Two moving pointers sweep across the scale upon actuation of
the BLADE CONTROL KNOBS permitting easy selection of the field size. The upper pointer indicates
the transverse dimension while the lower pointer indicates the longitudinal dimension.
Independent adjustment is provided by the BLADE CONTROL KNOBS on the face of the collimator.
They allow collimating to any desired rectangular field size up to 17" x 17" (43 cm x 43 cm) at a 40"
source-to-image distance. The right-hand knob controls the transverse dimension, while the left-hand knob:
controls the longitudinal dimension, while the left-hand knob controls the longitudinal dimension.
Depressing the FIELD LITE BUTTON energizes the high-intensity lamp. A timer automatically
switches the light off in approximately 15 to 20 seconds to keep lamp operation at a minimum. This time
interval can be adjusted by the serviceman if the user so desires.
NOTE: An interlock allows exposures and turns off the field light when x-ray rotor handswitch is en-
ergized.
The collimator can be rotated and locked positively at 0°, +/- 159, +/-45°, and +/- 90° from the front
position by detent. Depress the ROTATIONAL DETENT PLUNGER KNOB on the right side of the
collimator to move it from a detent position. Keep the plunger knob depressed until the approximate
position desired is reached. Then release the button and rotate the collimator slightly about this position
until the lock snaps in place.