Fluke Biomedical 07-601 - Manual (Page 9)

Test Interpretation
Test Interpretation
3
3-1
Section 3
Test Interpretation
3.1 Test Interpretation
1. A 6” image intensifier system observed via the monitor should be capable of resolving 30 mesh in
the center of the field, and a 9” system must display at least 20 mesh.
It has become common practice to adjust the television to flatten the top and bottom of the 9” field so
that only about 8” of the field are visible at the entrance aperture (most 9” image intensifier tubes are
really 8½ “ diameter). Therefore, most 9” systems should resolve 24 mesh. If the 6” systems are
similarly adjusted so that a 5” field is displayed, then they should resolve 35 mesh via the monitor.
When 9” systems are in the magnified mode, they must resolve 30 mesh and may resolve 35 mesh
via the monitor.
The monitor must be adjusted for both optical and electrical focus. It is a common occurrence in
many optical systems for the lens mount or the camera tube mount to become loosened with age so
that, when the position of the system is altered, it goes out of focus mechanically. If possible, tilt the
entire x-ray system and determine that the entire system remains in good focus.
2. Film camera systems must resolve everything present at the output phosphor. The camera should
be used to photograph the mesh pattern, and the lens adjusted for best focus during a series of test
exposures. The lens iris and x-ray factors should be adjusted for acceptable noise…decrease the
iris diameter and raise the mAs/image to decrease noise.