Studio delle prestazioni di un sistema a fosfori per mammografia ...

Chapter 3
Experimental setup
The entire set of measurements performed in order to evaluate the physical performances of a
complete system of CR mammography, based on a FUJI computed radiography system, have
been taken at the CSPO (“Centro Studi Prevenzione Oncologica”) in Florence (Italy) with the
supervision of the Physical Health Staff of the “Azienda Ospedaliera Careggi”.
In this chapter the characteristics of each hardware element will be described, with particular
emphasis devoted to the CR digital acquisition system FUJI FCR 5000 MA and to the X-ray
source, based on a mammography facility manufactured by Instrumentarium, in daily clinical
use at CSPO.
3.1 The mammography unit
The mammographic unit used as X-ray equipment in the present work is an Instrumentarium
model Diamond, with a molybdenum anode and an internal molybdenum filter 25 �m thick (a
25 �m rhodium filter and a 500 �m aluminum filter are also available but have not been used in
this investigation). The exit window isa1mmthick beryllium one. Great care has been taken to
perform all the measurements in a clinical diagnostic-like environment. The X-ray tube voltage
was set to the nominal 28.0 kVp, but a set of measurements have been performed to check the
precision of the control unit. A comparison of the value set on the unit control and of the same
as measured by a High Voltage Voltmeter (Victory Model Nero) is shown in Tab. 3.1.
The other parameter which can be adjusted by the operator is the mAs value, that is strictly
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