System information

the HVL measurement.
The test protocols
of the following two sections
describe methods to measure
the HVL to determine
compliance with minimum filtration requirements.
Since
the HVL is a function of the actual high voltage applied
to the x-ray tube, the protocols
assume the unit's kV
calibration is correct.
If such is not the case, the
measured HVL may
lead to an erroneous
conclusion
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