Performance evaluation of a newly developed semiconductor small animal PET scanner Sumitomo MIP-100

Objectives We quantitatively evaluated the performance of a newly developed semiconductor small animal PET scanner (Sumitomo MIP-100) and its feasibility for small animal experiments.

Methods All experiments were performed with an energy window greater than 170 keV. The spatial resolution was measured with a line source filled with ¹⁸F-FDG and the scatter fraction was measured using uniform cylindrical phantoms with diameters of 3 cm (mouse-size phantom) and 6 cm (rat-size phantom). We also measured the sensitivity, uniformity, and recovery coefficient using the NEMA NU2-2001 sensitivity phantom with a line source 15 cm in length and our original phantom.

Results The spatial resolutions in transaxial and axial directions were less than 1.2 mm and 1.6 mm FWHM, respectively, at 10 mm away from the center. The scatter fraction and the peak NEC rate for the mouse-size cylindrical phantom were 33.8% and 3.08 kcps, respectively, at a concentration of 184.8 MBq/ml. For the rat-size cylindrical phantom, they were 49.4% and 1.02 kcps, respectively, at 73.2 MBq/ml. The system sensitivity was 321 cps/MBq.

Conclusions The newly developed small animal PET scanner Sumitomo MIP-100 has a high spatial resolution, so that it is feasible to visualize the fine anatomical structures of small animals.