Nuclear Instruments and Methods in Physics Research A 571 (2007) 187–190 Ce doped lanthanum tri-bromide SPET scanner for molecular imaging R. Pani a , R. Pellegrini a,Ã , M.N. Cinti a , P. Bennati a , M. Betti a , F. Vittorini a , M. Mattioli b , G. Trotta a , V. Orsolini Cencelli c , R. Scafe` f , F. Navarria d , D. Bollini d , G. Baldazzi d , G. Moschini e , F. de Notaristefani g a Department of Experimental Medicine—University of Rome ‘‘La Sapienza’’, Viale Regina, Elena 324 - 00161, Rome, Italy b INFN and Department of Physics, ‘‘La Sapienza’’ University, Rome, Italy c INFN and National Institute of Nuclear Physics, ‘‘Roma III’’ University, Rome, Italy d INFN and Department of Physics, University of Bologna, Italy e INFN and Department of Physics, University of Padova, Italy f INFN and ENEA Casaccia Research Center, Rome, Italy g INFN and Department of Electronics Engineering, ‘‘Roma III’’ University, Rome, Italy Available online 7 November 2006 Abstract The availability of LaBr 3 :Ce crystals from St. Gobain has started various investigations in the field of medical imaging, in particular in PET, SPECT and Compton camera systems. At present LaBr 3 :Ce crystals are available in a continuous shape covering up to 10  10 cm 2 with a thickness of 1 cm, in contrast, serious concerns are arising in pixellated manufacturing. With the aim of verifying the potentials introduced by LaBr 3 :Ce for SPET imaging, two small g cameras based on Anger camera principle have been assembled and imaging performances were compared. Two crystals of LaBr 3 :Ce and NaI(Tl) with the same detection area (5  5 cm 2 ) and thickness of 5 and 1.5 mm, respectively were been integrally assembled with a H8500 Hamamatsu flat panel PMT. Through the thicker crystal, the LaBr 3 :Ce camera showed superior imaging and detection performances at 140 keV compared with the NaI(Tl) one, with 0.9 mm FWHM intrinsic spatial resolution, 8% FWHM energy resolution and 80% intrinsic detection efficiency. r 2006 Elsevier B.V. All rights reserved. PACS: 87.58.Pm; 87.62.+n; 87.58.Ce Keywords: Inorganic scintillators; LaBr 3 :Ce; Energy resolution; g ray imagers; Nuclear medicine 1. Introduction Last year, many research groups were attracted by the availability of LaBr 3 :Ce crystals from St. Gobain. A number of different applications are now under investiga- tion, particularly in the field of medical imaging. PET, SPECT and Compton camera instrumentations seem to have taken advantage of the performances of this new scintillation crystal. In fact, the crystal shows many advantages, compared with previous scintillators, like excellent energy resolution (3% and 6% FWHM at 662 and 140 keV photon energy, respectively), essentially because of the very high light output at a wavelength suited for the bi-alkali photocathode (63 000 light photons/ MeV) and the very small non-proportionality with the photon energy of the scintillator (less than 5%) [1–3]. In addition, the crystal has very good radiation absorption properties, high photofraction (similar to NaI(Tl)) and high speed (16 ns of scintillation decay time). Although St. Gobain is able to produce volumes as large as 3 in. in diameter by 3 in. in thickness, some limitations arise from the high hygroscopicity and fragility of the materials, which introduce serious concerns in pixellated manufactur- ing. Nowadays, LaBr 3 :Ce crystals are available in a continuous shape covering up to 10  10 cm 2 and thickness of up to 1 cm. In 2004, INFN relying on election properties for the SPECT application of cerium-doped lanthanum trihalides scintillators, promoted the development of a scintillation camera based on continuous crystal shape. The ARTICLE IN PRESS www.elsevier.com/locate/nima 0168-9002/$ - see front matter r 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.nima.2006.10.059 Ã Corresponding author. Tel./fax: +39 06 49918277. E-mail address: roberto.pani@uniroma1.it (R. Pellegrini).