Objectives: The aim of this study was to evaluate and benchmark the performance characteristics of the General Electric (GE) Discovery Molecular Imaging (MI) Digital Ready (DR) PET/CT.
Materials and methods: Performance evaluation against the National Electrical Manufacturers Association (NEMA) 2012 standard was performed on three GE Discovery MI DR PET/CT systems installed across different UK centres. The Discovery MI DR performance was compared with the Siemens Biograph mCT Flow, Phillips Ingenuity TF and GE Discovery 690 fully analogue PET/CT systems. In addition, as the Discovery MI DR is upgradable to the Digital MI with silicon photomultipliers, performance characteristics between analogue and digital were compared with assess potential benefits of a system upgrade.
Results: The average NEMA results across three Discovery MI DR scanners were: sensitivity 7.3 cps/kBq, spatial resolution full-width-half-maximum radial 5.5 mm, tangential 4.5 mm and axial 6 mm at 10 cm from the centre of the field-of-view, peak noise equivalent count rate 142 kcps, scatter fraction 37.1%, contrast recovery coefficients from the International Electrotechnical Commission phantom ranged from 52 to 87% for 10-37-mm diameter spheres.
Conclusion: All three Discovery MI DR systems tested in this study exceeded the manufacturer's NEMA specification, yet variability between scanners was noted. Discovery MI DR showed similar performance to Discovery 690 and Ingenuity TF, but lower sensitivity and spatial resolution than Biograph mCT Flow. The Discovery MI DR showed lower spatial resolution and contrast recovery than the 20-cm field-of-view Digital MI.