5. Measurements with the Barracuda System
Dental and Panoramic Dental
2012-10/4.3A
147
Barracuda & QABrowser Reference Manual
The definition of both what is the true kVp and
exposure time cannot be as easily determined
without study the waveform and select
appropriate measurement parameters as delay
and window. Introducing small CCD detectors
instead of film also demands carefully calibration
of single phase dental systems. The tube voltage
waveform is collected from 200 ms after start trig
and the kVp is calculated based on the
measuring window equal the remaining part of
the exposure time.
The dose value is collected for the whole
exposure time. If you need to change the
sensitivity, delay, or/and measuring window, tap
to show the settings and make your choices.
In the case of dental panoramic system the situation is somewhat different. Here the
kV and radiation waveform often is very well regulated.
The challenges instead arise for the mechanical setup needed to position the detector
in right position. The small and narrow field is only a few millimetres. The MPD detector
has very narrow detector area and is very thin and a special holder (optional) can be
used to position the MPD without any problem. The panoramic holder consist of the
MPD holder itself and three fixation holders for the cable. Magnets or "tape" can be
used to attach the holder system. Panoramic units that use digital detectors have much
smaller detector area and magnets cannot and should not be used close to the
detector area.
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