Optical Photon Propagation Characteristics and Thickness Optimization of LaCl<sub>3</sub>:Ce and LaBr<sub>3</sub>:Ce Crystal Scintillators for Nuclear Medicine Imaging
Stavros Tseremoglou,
Christos Michail,
Ioannis Valais,
Konstantinos Ninos,
Athanasios Bakas,
Ioannis Kandarakis,
George Fountos,
Nektarios Kalyvas
Affiliations
Stavros Tseremoglou
Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of Biomedical Engineering, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece
Christos Michail
Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of Biomedical Engineering, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece
Ioannis Valais
Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of Biomedical Engineering, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece
Konstantinos Ninos
Department of Biomedical Sciences, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece
Athanasios Bakas
Department of Biomedical Sciences, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece
Ioannis Kandarakis
Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of Biomedical Engineering, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece
George Fountos
Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of Biomedical Engineering, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece
Nektarios Kalyvas
Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, Department of Biomedical Engineering, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece
The present study focuses on the determination of the optimal crystal thickness of LaCl3:Ce and LaBr3:Ce crystal scintillators for Nuclear Medicine Imaging applications. A theoretical model was applied for the estimation of the optical efficiency of the two single-crystal scintillators in terms of Detector Optical Gain (DOG). The theoretical model was validated against the experimental values of the Absolute Efficiency (AE) of the two crystals, obtained in the energy range 110 kVp–140 kVp. By fitting the theoretical model to these experimental data, the propagation probability per elementary thickness k was determined and DOG was theoretically calculated for crystal thicknesses from 0.005 cm to 2 cm, in the energy range of Nuclear Medicine Imaging. k values for LaCl3:Ce and LaBr3:Ce crystals were significantly higher compared to other single-crystal scintillators. The DOG values of the two crystals may serve as evidence that the LaBr3:Ce crystal exhibits significantly better performance compared to the LaCl3:Ce crystal. With an increase in energy, the optimum thickness increases for both crystals. Additionally, crystal efficiency generally demonstrates a decrease beyond a certain thickness. The aforementioned insights may provide valuable guidance for the design and optimization of crystal scintillators in Nuclear Medicine Imaging systems.
