Specifications

XR 8-2.14 VISUAL DEFINITION (RADIOGRAPHIC) OF X-RAY LIGHT FIELD
REQUIREMENT - Means shall be provided for visually defining the perimeter of the X-
Ray field. The total misalignment of the edges of the visually defined field with the
respective edges of the X-Ray field along either the length or width of the visually
defined field shall not exceed 2 percent of the distance from the source to the center of
the visually defined field when the surface upon which it appears is perpendicular to the
axis of the X-Ray beam (see 21 CFR 1020.31 (d) (2)).
.01 METHOD 1 - BRH-FDA COMPLIANCE TEST METHOD
A. EQUIPMENT REQUIRED
1. BRH/FDA compliance test stand (including slide assembly)
2. Four metal marker strips
3. Plastic cassette, loaded with direct print paper or film
B. PROCEDURE
1. Attach the spacer, positioned out of the primary beam to the test stand.
Center the stand on the table. Center the source over the stand, assure
by the means provided that the axis of the X-Ray beam is perpendicular
to the plane of the image receptor, and bring the beam-limiting device
down into firm contact with the spacer. Select the MANUAL mode of
operation (there must not be a cassette in the cassette holder).
2. Insert the slide assembly, grid side up, into slot 6 of the test stand and
the focal spot assembly into slot 1 (Figure 5-2). Place a cassette loaded
with direct print paper or film into the slide assembly.
3. Adjust the collimator so that no part of the light-field intersects any portion
of the top of the test stand. (Further collimation to a light field of less
than 15 by 20 centimeters (6 by 8 in) on the side assembly grid may be
desirable to assure that the X-Ray field will be fully contained on the
direct print paper for film in the slide assembly).
4. Position the outer edge of each metal strip to correspond with each side
of the light-field. One end of the metal strip shall extend to the center line
of the respective grid arm.
5. Select proper technique factors and make an exposure (may require
several exposures to obtain 1 R to the direct print paper).
6. Develop the direct print paper or film.
November 2005 ( 5 - 9 ) Linear MC150-C Collimator