title: Performance evaluation of the Philips MOSAIC small animal PET scanner.
abstract: OBJECTIVE
  In this study an evaluation of the performance of the Philips MOSAIC small animal PET scanner is presented, with special emphasis on the ability of the system to provide quantitatively accurate PET images.
  
  
  METHODS
  The performance evaluation was structured according to NEMA-like procedures.
  
  
  RESULTS
  The transaxial spatial resolution of the system (radial component) ranged between 2.7 mm FWHM at the centre and 3.2 mm FWHM at a radial offset of 45 mm from the centre. The axial spatial resolution of the system ranged between 3.4 mm FWHM at the centre and 5.8 mm FWHM at a radial offset of 45 mm from the centre. The scatter fraction was determined for a mouse- as well as for a rat-sized phantom, and the values obtained were 9.6% and 16.8%, respectively. For the mouse phantom, the maximum count rate measured was 560 kcps at 93 MBq; the maximum NEC rate equalled 308 kcps at 1.7 MBq/ml. For the rat phantom, these values were 400 kcps at 100 MBq and 129 kcps at 0.24 MBq/ml, respectively. The sensitivity of the system was derived to be 0.65%. An energy window between 410 and 665 keV was used in all experiments.
  
  
  CONCLUSIONS
  The MOSAIC system exhibits moderate spatial resolution and sensitivity values, but good NEC performance. In combination with its relatively large field of view, the system allows for high-throughput whole-body imaging of mice and rats. The accurate measurement of relative changes in radiotracer distributions is feasible.
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar der Technischen Universitaet Muenchen, Ismaninger Strasse 22, 81675, Munich, Germany. m.huisman@lrz.tum.de
authors.forename: Marc C
authors.initials: MC
authors.lastname: Huisman
authors.forename: Sybille
authors.initials: S
authors.lastname: Reder
authors.forename: Axel W
authors.initials: AW
authors.lastname: Weber
authors.forename: Sibylle I
authors.initials: SI
authors.lastname: Ziegler
authors.forename: Markus
authors.initials: M
authors.lastname: Schwaiger
mesh_terms: D000818:Animals; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods; D051379:Mice; D049268:Positron-Emission Tomography / Q000295:instrumentation* / Q000662:veterinary*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D051598:Whole Body Imaging / Q000295:instrumentation* / Q000662:veterinary*