Lanthanum scintillation crystals for gamma ray imaging

Over the last 3 years, there has been a growing interest in the development of a new class of fast scintillators such as LaCl3:Ce and LaBr3:Ce. Their superior energy resolution is opening an easier way to improve spatial resolution. In this paper we present the results obtained from the first LaBr3:Ce small gamma camera. It is based on continuous 50×50 mm2 crystal, 5 mm thick, integral assembled with a Hamamatsu Flat panel PMT. This detector configuration permits the narrowest light distribution with the highest light output in order to obtain the best spatial and energy resolution values, respectively. At the same time, 5 mm crystal thickness carries out 80% efficiency at 140 keV photon energy. Measurements of spatial resolution are also compared with the analogous ones obtained from another 50×50 mm2 LaBr3:Ce crystal, assembled with a 3 mm glass optical window. Energy resolution values have been furtherly compared with ones obtained from a LaBr3:Ce 1 in. diameter and thickness optimized for spectrometric measurements. The first LaBr3:Ce gamma camera shows excellent intrinsic spatial resolution values such as 0.9 mm, with a best energy resolution value of 6.5% at 140 keV photon energy.