a. Set the fluoroscope machine controls to automatic brightness.
b. Turn the mA and kVp controls to maximum, if possible.
c. Adjust the height of the fluoroscope tower to 12 inches above the tabletop.
d. Place the dosimeter chamber in the center of the radiation field
fluoroscopically (see figure 5-9).
Figure 5-9. Centering the dosimeter chamber to center of radiation field.
e. Adjust the fluoroscope shutter so that it is just visible on the
edges of the image, and it should not cover any active volume of the chamber.
f. Turn the dosimeter to the exposure rate mode.
g. Place the supports around the probe.
h. Place the lead sheets on the supports.
Put on your lead apron.
j. Turn on the fluoroscope long enough to stabilize the automatic brightness
k. Ensure that the beam is completely attenuated (absorbed) by the lead. There
should be no light seen on the monitor.