title: Sub-100 ps coincidence time resolution for positron emission tomography with LSO:Ce codoped with Ca.
abstract: The coincidence time resolution (CTR) becomes a key parameter of 511 keV gamma detection in time of flight positron emission tomography (TOF-PET). This is because additional information obtained through timing leads to a better noise suppression and therefore a better signal to noise ratio in the reconstructed image. In this paper we present the results of CTR measurements on two different SiPM technologies from FBK coupled to LSO:Ce codoped 0.4%Ca crystals. We compare the measurements performed at two separate test setups, i.e. at CERN and at FBK, showing that the obtained results agree within a few percent. We achieve a best CTR value of 85 ± 4 ps FWHM for 2 × 2 × 3 mm(3) LSO:Ce codoped 0.4%Ca crystals, thus breaking the 100 ps barrier with scintillators similar to LSO:Ce or LYSO:Ce. We also demonstrate that a CTR of 140 ± 5 ps can be achieved for longer 2 × 2 × 20 mm(3) crystals, which can readily be implemented in the current generation PET systems to achieve the desired increase in the signal to noise ratio.
authors.affiliation: CERN, Geneva 23, CH-1211, Switzerland.
authors.forename: Mythra Varun
authors.initials: MV
authors.lastname: Nemallapudi
authors.forename: Stefan
authors.initials: S
authors.lastname: Gundacker
authors.forename: Paul
authors.initials: P
authors.lastname: Lecoq
authors.forename: Etiennette
authors.initials: E
authors.lastname: Auffray
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ferri
authors.forename: Alberto
authors.initials: A
authors.lastname: Gola
authors.forename: Claudio
authors.initials: C
authors.lastname: Piemonte
mesh_terms: D002118:Calcium / Q000737:chemistry* / Q000528:radiation effects; D002563:Cerium / Q000737:chemistry* / Q000528:radiation effects; D015902:Gamma Cameras; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008187:Lutetium / Q000737:chemistry* / Q000528:radiation effects; D049268:Positron-Emission Tomography / Q000295:instrumentation* / Q000379:methods*; D012588:Scintillation Counting / Q000295:instrumentation*; D059629:Signal-To-Noise Ratio; D017640:Silicates / Q000737:chemistry* / Q000528:radiation effects; D013997:Time Factors; D014057:Tomography, X-Ray Computed
chemical_list: D017640:Silicates; C477682:lutetium orthosilicate; D002563:Cerium; D008187:Lutetium; D002118:Calcium