Speaker
Mr
Nikolaos Efthimiou
(Department of medical instrumentation-Technological educational insitution)
Description
Computer simulation modeling has been proved as a reliable and promising technique
for the evaluation of the performance of medical imaging systems. The purpose of the
present work was to model modern X-ray detection system and to investigate the effect
of scintillator material on the detector's output signal and the image quality. The
scintillators were used in the form of screens (layers) of various thicknesses and
the parameters investigated were the Modulation Transfer Function (MTF), the
Detective Quantum Efficiency (DQE) and the Energy Absorption Efficiency (E.A.E.). The
results of some commonly used scintillator detectors (YAG:Ce, YO3, ZnSCdS, Lu3Al5O3,
CdWO4, LuO3) are presented. A computer algorithm, based on commercially available
software, was developed to simulate the irradiation process. Typical radiographic
conditions including the beam quality, in terms of the X-ray spectrum and exposure,
were considered as input parameters (X-ray photons spectrum from 30keV to 140keV).
For simulation purposes the intrinsic conversion efficiency (nc), the total number of
optical photons produced per incident X-ray (m0), the attenuation coefficients and
other optical parameters of the scintillator materials under study, were taken as
input data. The complete simulation procedure was performed in a specially designed
user-friendly Graphical User Interface (GUI). The results showed that, under typical
examination conditions (80kV, 1mAs and 80 mg cm2 coating thickness), the MTF and DQE
curves were affected by the X-ray energy absorption efficiency and the intrinsic
properties of the scintillator materials. The Lu3Al5O7 scintillator presented similar
behavior to that of ZnSCdS:Ag , exhibiting similar DQE at zero spatial frequency
(0.16) and MTF at 200 lp (0.15). The YAG:Ce scintillator exhibited higher MTF at 200
lp (0.2) compared to the one of the YO3:Eu scintillator (0.1), but lower DQE at zero
spatial frequency (0.062).
Author
Mr
Nikolaos Efthimiou
(Department of medical instrumentation-Technological educational insitution)
Co-authors
Mr
Anastasios Konstantinidis
(Department of Medical Physics, School of Medicine, university of Patras,Patra,Greece)
Mr
Christos Michail
(Department of Medical Physics, School of Medicine, university of Patras,Patra,Greece)
Dr
Dimitrios Nikolopoulos
(Department of Medical Instrumentation, Technological Educational Institution of Athens, 12210 Egaleo, Greece)
Prof.
Dionysios Cavouras
(Department of Medical Instrumentation, Technological Educational Institution of Athens, 12210 Egaleo, Greece)
Dr
George Loudos
(Department of Electrical and Computer Engineering, National Technical University of Greece)
Prof.
George Panayiotakis
(Department of Medical Physics, School of Medicine, university of Patras,Patra,Greece)
Mr
George Patatoukas
(Department of Medical Physics, School of Medicine, university of Patras,Patra,Greece)
Mr
Ioannis Gaitanis
(Department of Medical Instrumentation, Technological Educational Institution of Athens, 12210 Egaleo, Greece)
Prof.
Ioannis Kandarakis
(Department of Medical Instrumentation, Technological Educational Institution of Athens, 12210 Egaleo, Greece)
Mr
Ioannis Valais
(Department of Medical Instrumentation, Technological Educational Institution of Athens, 12210 Egaleo, Greece)
Prof.
Kostantinos Kourkoutas
(Department of Physics, Chemistry and Materials Technology, Technological Educational Institution, 12210 Egaleo, Greece)
Dr
Nektarios Kalibas
(Greek Atomic Energy Commission, 153 10, Ag. Paraskevi P.O BOX 60092, Greece)
Mr
Stratos David
(Department of Medical Physics, School of Medicine, university of Patras,Patra,Greece)
