GE AMX-II

GENERAL ELECTRIC MEDICAL SYSTEMS AMX-II X-RAY UNIT
10-377
b.
SM A0654E
Field size indicators of length and width on collimator shall each agree with actual x-ray
field size at the receptor to within 1.8% of SID when beam axis is perpendicular to the plane
of the film.
Establish test variables using single cassette size (14’ x 17°) (35.5 cm x 43.2 cm) for a vertical x-ray
beam at SID distances of 40” (1.016 m) and 72” (1.83 m).
Procedure |
a. Load a large cassette and place on floor (14” x 17” (35.5 cm x 43.2 cm) preferred size).
b. Position Diagnostic Source assembly for vertical x-ray beam and a SID of 40” (1.016 m). Us-
ing collimator light to carefully center x-ray beam on cassette. °
c. Carefully adjust collimator field size indicators to a common field size smaller than the image
receptor—use 12” x 12” (30.48 cm x 30.48 cm) field size for a 14” x 17” (35.5 cm x 43.2 cm)
cassette.
d. Assemble and attach RAT to collimator using RAT holding fixture.
e. Use Collimator Lamp, note and record where edges of light field appear on RAT grid pattern.
4 4 . .
af Exposure and develop film (recommend 4 MAS at 50 KVP for par speed film with medium screens
at 40” (1.016 m) and 16 MAS at 72”) (1.83 m).
g. Measure x-ray image length and width. Each must agree with numerical indicator settings
(step c) within 1.8% of SID.
h. Mark light field (step e) on x-ray field. Total misalignment of either length or width edges must
not exceed 1.8% of SID.
i. Repeat steps a thru h for a SID distance of 72” (1.83 m).
If edge to edge light field and x-ray field alignment exceeds 1.8% of SID adjust as follows:
a. Remove the knobs and nameplate per instructions in Section 4-1.
b. With nameplate removed, temporarily reinstall knobs and adjust field size to same setting as
in 3C.
c. Slightly loosen the two light housing mounting screws. See illustration 4-12.
d. With RAT in holding fixture beneath collimator, shift light housing so that light field aligns
with the grid pattern of the x-ray field from step 3h.
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