IN-FIELD TESTING OF A NEW INSTRUMENT FOR QUALITY-CONTROL IN MAMMOGRAPHY

Routine quality control procedures for mammography need a periodical t esting of the X ray units. The checks of kV(p) accuracy, mA linearity, exposure reproducibility and HVL consistency require several instrume nts (non-invasive kV(p) meter, dosemeter, absorbers, etc.) and a lot o f time. The use of a new instrument for a quick and easy measurement o f kV(p), ripple, HVL, exposure time and incident air kerma is presente d. The instrument, composed of an X ray probe and a portable computer, allows the evaluation of the above parameters in a single shot. Two m ammographic units have been routinely tested measuring kV(p), HVL, exp osure time and incident air kerma. The evaluation has been performed e xposing the probe during the execution of a performance phantom radiog raph. The relationships between the fluctuations of the measured param eters are compared with the limiting values proposed by CEC guidelines . Correlation analysis of the whole data set allows malfunctioning ide ntification. The instrument works properly and is very useful in quali ty control activity.