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5. Measurements with the Piranha System
Dental and Panoramic Dental
Piranha & QABrowser Reference Manual 2014-06/5.5C
126
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 Piranha detector
has very narrow detector area and is very thin and a special holder (optional) can be
used to position the Piranha without any problem. Panoramic units that use digital
detectors have much smaller detector area and magnets cannot and should not be used
close to the detector area.