In order to set up a successful mammography screening program in the Republic
of Srpska, a Siemens Mammomat 1000 X-ray machine was selected for analysis as
the said mammography system is widely used in clinical practice. The
variations in tube parameters (specific air kerma, high-voltage accuracy and
reproducibility, linearity between exposure and dose exposure time) were
monitored over a five-year period, from 2008 to 2012. In addition, due to
observed daily fluctuations for chosen parameters, a series of measurements
were performed three times a day within a single-month period (mainly October
2012). The goal of such an experimental set up is to assess short-term and
long-term stability of tube parameters in the given mammography unit and to
make a comparison between them. The present paper shows how an early
detection of significant parameter fluctuations can help eliminate
irregularities and optimize the performance of mammography systems.
Improvement of the long-term stability of ZnSnO thin film transistors by tungsten incorporation using a solution-process method