Performance comparison between NeuroPET-CT and Siemens ECAT HR+: NEMA and patient studies

Objectives The newly developed mobile NeuroPET-CT scanner is a dedicated high-resolution, high-sensitivity brain PET-CT. There has been significant hardware and software development since we first reported NEMA performance, as well as extensive clinical use. We report on performance of the NeuroPET-CT in phantom and clinical studies and compare to Siemens ECAT HR+.

Methods NeuroPET-CT has been extensively used in 100+ patient studies at MGH. It appears that best image quality for patient studies can be achieved using a clinical setting, which has a coincidence timing window of 7 ns, 400-650 keV energy window, and half axial field of view (FOV) maximum ring difference. Sensitivity and noise equivalent count (NEC) rate have been re-measured based on the procedures of NEMA PET standard for the default clinical setting. For one patient FDG study, the HR+ image volume was registered to the NeuroPET image volume using rigid registration. The contrast (signal/background) in the caudate nucleus and putamen was computed for each scanner.

Results The measured sensitivity, normalized to the activity placed in the 70 cm tube, was 0.79%, 0.83%, and 0.93% for r=0, 5, and 10 cm, respectively. The sensitivity was 24% (r=0) greater than the HR+ sensitivity. The peak NEC rate was 20.6 kHz measured at 2.86 kBq/ml. The FDG patient study shows that NeuroPET-CT yielded 17% higher contrast than HR+ in the caudate nucleus and putamen.

Conclusions NeuroPET-CT was found to have higher spatial resolution, sensitivity, and NEC rate (at low activity level) than HR+. FDG patient studies also show that NeuroPET-CT yields better PET image quality than HR+.