LORAD AFFINITY Series, Service Manual

Page: 101 / 214

P/N 9-500-0255 4-45
Service Manual
Chapter 4: Calibrations and Performance Checks
X-ray and Light Field Check and Alignment Procedures
7.2 Exposing and Viewing the X-ray Field
The glow emitted from the screen must be observed from behind the protective radiation
shield (or its equivalent). The glow is fairly dim under normal lighting conditions, so darken
the room to achieve the best possible results. Higher kV settings result in a brighter glow,
however, care must be taken to prevent overheating the x-ray tube during the repetitive
exposures that are usually necessary during the alignment procedure.
Caution: Prolonged, repeated exposures at high kV or mAs settings may cause
permanent damage to the x-ray tube. Use caution not to exceed the
thermal capacity of the tube during this procedure.
Since it is necessary to make repetitive exposures, the system can be set so that there is only
a fifteen-second Standby interval between exposures. On the Microprocessor Board, set DIP
Switch S2 switch 1 to ON. Remember to set this switch to OFF at the end of this procedure.
Below is the recommended method to use when making exposures and determining
required adjustments during this procedure:
1. Make one exposure per edge (e.g., concentrate only on evaluating one edge each time
an exposure is made).
2. Use short exposure durations (one to two seconds).
3. Remember the direction of movement for that edge, and the approximate distance
required for the movement each time an exposure is made.
Keep in mind, attempting to remember the directions and amounts for more than one edge at
a time requires longer exposures, and usually, the same number of exposures as would be
necessary when doing one edge at a time.