Specifications

C. PROCEDURE
1. Align the tube unit and image receptor and set the SID with the normal
operating aids (detents, scales, lights, etc.)
2. Load cassette and insert into image receptor.
3. Close shutters to a size smaller than that of the cassette placed into the
image receptor.
4. Position the test stand in accordance with the manufacturer’s instructions.
5. Energize the field light and record or define the position of the four light
field edges as shown on the graduated template or position four metal
markers so that the outer edge of each metal marker corresponds to an
edge on each side of the light-field or both.
6. Select proper technique factors, make an exposure, and develop film.
D. VERIFICATION OF COMPLIANCE
1. Calculate 2 percent of the actual SID and record.
2. Compare the edges of the X-Ray field to the edges of the light field as
defined by the outer edges of the metal markers or by the graduated
scale.
3. Measure the distance between the edges of the two fields for each side
of the rectangular fields (see Figure 5-3).
4. Arithmetically sum the misalignment of opposite sides, regardless of sign,
of the rectangles, to yield misalignment in each of the two directions.
Length misalignment = L
1
+ L
2
≤ 2% SID
Width misalignment = W
1
+ W2 ≤ 2% SID
Both the length and width misalignment must be less than 2 percent SID
as calculated in Step 1.
NEMA Standards 5-15-79 1/3
XR 8-2.15 INTENSITY OF LIGHT FIELD ILLUMINATION
.01 REQUIREMENT
A. GENERAL
1. The image of the radiation field on the film must be of uniform density
with sharply defined edges.
November 2005 ( 5 - 14) Linear MC150-C Collimator