11. Repeat the measurement for other generator settings or select an Application (tap
Appl) to measure further.
5.2.4 Quick-HVL and Total Filtration
Total filtration
A quicker way to get an estimated value with acceptable accuracy is to use the "one-
shot" method that is a standard complementary information feature for the Piranha kVp
determination (described earlier in this manual). The total inaccuracy is about ±0.3 mm
in the range of 2 to 10 mm and ±10 % in the range 10 to 25 mm, see Specifications,
Piranha . The purpose of this value is to always be able to calculate correct kVp and
dose value independent of beam-filtration. But it can also be used as a quick way to
estimate the filtration and alert you if the filtration has changed since last measurement
of the HVL value.
The following examples very clearly shows the excellent independence of the beam
filtration for kV and dose readings.
Three exposures were made with 3 mm Al, 6 mm Al, and 12 mm Al. The Piranha was
used to measure kVp, exposure time, dose, and dose rate. The pictures are stored
when the QABrowser shows estimated total filtration. The kVp value is also visible.
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