title: Performance evaluation of the microPET R4 PET scanner for rodents.
abstract: The microPET R4 scanner is a dedicated positron emission tomograph (PET) for studies of rodents. A number of scanner parameters such as spatial resolution, sensitivity, scatter, and count rate performance were determined in this work, which showed that the microPET R4 is a suitable PET scanner for small animals like mice and rats. In the center of the field of view (FOV) a maximal sensitivity of 43.66 cps/kBq for a centered point source was calculated from a measurement with a germanium-68 line source within an energy widow of 250-750 keV. A spatial resolution of 1.85 mm full-width at half-maximum (FWHM) in the axial direction and 1.66 mm FWHM in the transaxial direction was measured in the center with a 1-mm-diameter sodium-22 point source. Within the inner 20 mm of the FOV the volumetric resolution is better than 15.6 micro l, corresponding to a linear resolution of less than 2.5 mm in all three dimensions. Images of a high-resolution phantom and from mice and rat studies illustrate the good performance of the scanner. A maximal noise equivalent count rate (NECR) was reached at 174 kcps for a mouse phantom and at 93 kcps for a rat phantom (energy window 250-750 keV). Scatter fractions were measured between 0.30 and 0.42 for an energy window of 250-750 keV and phantom diameters similar to mice and rats. A comparison with the microPET P4 model for primates illustrates the gain in sensitivity due to a smaller detector ring diameter but also the changes in NECR.
authors.affiliation: Max-Planck-Institute for Neurological Research, Gleuelerstrasse 50, 50931 Cologne, Germany. knoess@pet.mpin-koeln.mpg.de
authors.forename: Christof
authors.initials: C
authors.lastname: Knoess
authors.forename: Stefan
authors.initials: S
authors.lastname: Siegel
authors.forename: Anne
authors.initials: A
authors.lastname: Smith
authors.forename: Danny
authors.initials: D
authors.lastname: Newport
authors.forename: Norbert
authors.initials: N
authors.lastname: Richerzhagen
authors.forename: Alexandra
authors.initials: A
authors.lastname: Winkeler
authors.forename: Andreas
authors.initials: A
authors.lastname: Jacobs
authors.forename: Rhonda N
authors.initials: RN
authors.lastname: Goble
authors.forename: Rudolf
authors.initials: R
authors.lastname: Graf
authors.forename: Klaus
authors.initials: K
authors.lastname: Wienhard
authors.forename: Wolf-Dieter
authors.initials: WD
authors.lastname: Heiss
mesh_terms: D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging*; D002415:Cats; D004867:Equipment Design; D019544:Equipment Failure Analysis; D051379:Mice; D008904:Miniaturization; D019047:Phantoms, Imaging; D051381:Rats; D015203:Reproducibility of Results; D012377:Rodentia; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed / Q000295:instrumentation* / Q000379:methods*; D014915:Whole-Body Counting / Q000379:methods