PET and SPECT of Neurobiological Systems

Abstract

1805 Objectives A PET image reconstruction tool (Q.Clear®) has been recently introduced that allows more iterations of the raw PET data than the standard OSEM image reconstruction, to enable contrast recovery without amplifying noise. Here we qualitatively and semi-quantitatively compared Q.Clear® with the standard OSEM image reconstruction available on our clinical PET/CT scanners (GE Discovery 600 and 690) using patient data. Methods PET datasets from 30 previously acquired clinical research scans (16 68Ga-DOTA TATE, 11 18F-FPPRGD2, 1 18F-FLT, 2 18F-FSPG) were reconstructed using Q.Clear® (25 iterations with 3 different regularization strength or “beta” values) and compared to standard reconstruction for Discovery 600 (2 iterations and 32 subsets; with PSF modeling) and 690 (2 iterations and 24 subsets; with PSF modeling) scanners. Each of the 4 reconstructions/scan were reviewed blindly by 2 experienced nuclear medicine physicians and scored 1-5 (1 poor, 5 excellent quality). The SUVmax of the smallest lesion detected in each patient was also measured for comparison. The paired Welch t-test was used for statistical analysis. Results Significant differences (P Conclusions Q.Clear® with a higher number of iterations maintains image quality. Visual analysis confirmed that overall image quality is improved and may allow for improved detection of small lesions as compared to the image quality from the standard OSEM algorithm. Research Support GE Healthcare