Fluke Biomedical 07-611 - Manual (Page 9)

Operation
X-Ray Tube Focal Spot Measurements
2
2-3
14. Select a technique of 28 kVp and 50 mAs for mammographic units. For R/F units use 75 kVp, 300
mA for direct exposure film and 30 mAs for cassette exposure.
15. Expose the film at the selected technique factor. Film density should be between 0.80 and 1.20
above the base-plus-fog level of the film.
Figure 2-4. Focal Spot Test Stand on Table Figure 2-5. Focal Spot Test Stand
Alignment Device
(Over-Table X-Ray Tube) on Top of Test Stand
Figure 2-6. Radiograph of the Five Beads in the Focal Spot Test Stand Alignment Device:
a. Correctly aligned
b. Improperly aligned
Table 2-1.
Minimum Magnification for Slit, Pinhole,
or Star Measurement Technique
Nominal Focal
Spot Size (F, mm)
Magnification
F < 0.4 > 3
0.4 < F < 2.5 > 2
F > 2.5 > 1
a. b.