Comparison of NEMA NU 4-2008 vs NEMA NU 2-2001 for the performance evaluation of the microPET R4 system

Positron Emission Tomography (PET) techniques have gained an important role in the diagnosis of human diseases as well as for pharmaceutical and biomedical research. In order to best optimize their capabilities, evaluation of their performance has to be achieved through standardized methodology from specific standards. The aim of this work was to assess the performance evaluation of the microPET R4 system for imaging rodents according to the new NEMA NU 4-2008 standards and compare it against its previous evaluation according the adapted clinical NEMA NU 2-2001. All measurements were made for an energy window of 350-650 keV. Spatial resolution of 2.12 mm FWHM in the radial direction, 2.66 mm FWHM in the tangential direction and 2.23 mm FWHM in the axial direction was measured in the centre of the axial FOV. Scatter fraction for mouse and rat phantoms were found to be 9.5% and 22% respectively. The maximum noise-equivalent count rate (NECR) was 110 kcps at 121.3 MBq for the rat phantom 287 kcp at 129.8 MBq for the mouse phantom. The absolute sensitivity of the scanner was found to be 1.66% at the centre of the field of view.