Specifications

2. The graduated template is utilized to minimize the amount of error
introduced into the measurement of the X-Ray field size.
3. The actual versus indicated source-to-image distance (SID) must be
determined prior to performing this test.
B. EQUIPMENT
1. Manufacturer’s recommended test stand.
2. Cassettes and film.
3. Graduated template.
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. Turn on the light localizer.
5. At or near the center of a light field quadrant, determine the illuminance by subtracting the
ambient light level from the corresponding light level as measured when the light localizer is
energized. Do not move the photometer between measurements.
6. Repeat the procedure for the remaining three quadrants.
7. Determine the average illuminance of the four light field quadrants.
8. Record the model number, serial number, and the date of calibration of test instrument.
D. VERIFICATION OF COMPLIANCE
Verify that the average illumination is not less than 160 lux (15 footcandles).
NEMA Standards 5-15-79
.02 METHOD II - INDIRECT TEST
A. GENERAL
1. This indirect test is feasible after the correlation between light output and
voltage is made; the manufacturer then specifies a voltage to be
measured or adjusted, or both.
November 2005 ( 5 - 15) Linear MC150-C Collimator
2. Make certain that all surfaces in the light path are clean and unobstructed.
B. EQUIPMENT