Wydział Chemii

Ioannis Seferis

N. I. Kalyvas

I. G. Valais

C. M. Michail

P. F. Liaparinos

G. P. Fountos

Eugeniusz Zych

I. S. Kandarakis

G. S. Panayiotakis

Bruce R. Whiting

Christoph Hoeschen

Robert M. Nishikawa

2013

SPIE

Bellingham

86683W/1-86683W/8

10.1117/12.2015265

Proceeding of SPIE. Vol. 8668, Medical imaging 2013 : physics of medical imaging.

978-0-8194-9442-9

Naukowa

Angielski

Rozdział książki

Powder phosphors scintillators are used in indirect digital radiography as x-ray to light converters coupled to electronic optical sensors (photodiodes, CCDs, CMOS). Recently, nanophosphors have been reported to have enhanced luminescence efficiency. The purpose of the present study was to evaluate Lu₂O₃:Eu nanophosphor as a candidate for digital medical imaging applications. Lu₂O₃:Eu was employed in the form of a 30.2 mg/cm² powder screen with 50 nm grain size and 5% Eu concentration. Both the nanophosphor material and the screen were prepared in our laboratories. Parameters such as the Absolute Efficiency-AE (light energy flux over exposure rate), the Luminescence Efficiency- XLE (Light energy flux over incident x-ray energy flux), Detector Quantum Gain-DQG (optical quanta emitted per incident x-ray quantum) and the light spectral compatibility to electronic optical sensors (Effective Efficiency) were investigated under x-ray excitation in the radiographic energy range. Results were compared with previously published data for a 33.1 mg/cm² Gd₂O₂S:Eu conventional phosphor screen. It was found that Lu₂O₃:Eu nanophosphor has higher AE and XLE by a factor of 1.32 and 1.37 on average, respectively, in the whole radiographic energy range. DQG was also found higher in the energy range from 50 kVp to 100 kVp and comparable thereafter. Effective efficiency was found with high values for electronic optical sensors such as CCDs and CMOS, due to the high spectral compatibility with the upper visible wavelength range. These results indicate that Lu₂O₃:Eu nanophosphor could potentially be considered for applications in digital x-ray radiography detectors.

nanophosphors, Lu203:Eu, Radiography, Absolute efficiency, Detector Quantum Gain (DQG), Liminescence efficiency (XLE), Effective efficiency (neff)

http://dx.doi.org/10.1117/12.2015265