e-Περιοδικό Επιστήμης & Τεχνολογίας

e-Journal of Science & Technology, (e-JST)


Luminescence Efficiency of fast Yttrium Aluminum Garnet Phosphor Screens for use in Digital Breast Tomosynthesis.

Stratos L. David1, Christos M. Michail1,  Ioannis G. Valais2, Ioannis Seferis2, George Varaboutis2, Stauros Gatsos2,
Adrianos E. Toutountzis1, George Fountos2, Ioannis S. Kandarakis2, George S. Panayiotakis1

 1 Department of Medical Physics, Medical School University of Patras 265 00 Patras, Greece

2 Department of Medical Instruments Technology  Technological Educational Institution of Athens Ag. Spyridonos, Aigaleo, 122 10 Athens, Greece

Corresponding author:  kandarakis@teiath.gr

 Abstract. In the present study scintillating screens prepared from Y3Al5O12:Ce (YAG:Ce) powder phosphor were evaluated for use in digital mammography. YAG:Ce has never previously been used in X-ray medical imaging, however since it emits green light (i.e peak at 550nm), it is expected to match well the spectral sensitivities of most photodetectors (photodiodes, CCDs and amorphous silicon sensors) incorporated in various digital breast tomosynthesis detectors. YAG:Ce was purchased in powder form and was used in order to prepare test screens in the laboratory. Screens were evaluated by determining the quantum detection efficiency (QDE), the energy absorption efficiency (EAE), the absolute luminescence efficiency (AE), the X-ray luminescence efficiency (XLE), the light emission spectrum, the X-ray to light intrinsic conversion efficiency and the spectral compatibility with various digital photodetectors. Results were compared with phosphor materials commercially employed in X-ray imaging such as CsI:Tl and Gd2O2S:Tb. Maximum YAG:Ce emission efficiency was observed for the 63 mg/cm2 screen at 49 kVp. The spectral compatibility with amorphous silicon photodiodes (0.93) and CCDs (0.95) was found to be very high, better than the corresponding compatibility of the CsI:Tl screen, mostly used in current digital radiography detectors. Taking into account the YAG:Ce overall performance, its short decay time as well as its spectral compatibility with amorphous silicon detectors and CCDs, YAG:Ce could be of interest for further investigation for applications in digital breast tomosynthesis detectors.

Keywords: Luminescence Efficiency, Matching Factor, Powder Phosphors, Mammography.