Comparison of the effects of FBP and OSEM on the quantification of renal cortical blood flow using O-15 water dynamic PET

We compared the renal cortical blood flow (RCBF) with factor analysis (FA) and H215O PET images reconstructed by filtered backprojection (FBP) and ordered subset expectation maximization (OSEM) if the quantification of the renal cortical blood flow is affected by the reconstruction methods. H215O PET scan was performed on 1 normal dog and the image was reconstructed by both OSEM and FBP reconstruction methods. Then, we applied FA to the dynamic renal PET images to extract pure time activity curves for he estimation of RCBF and these values were validated with microsphere experiment. In microsphere study, the RCBF of left kidney with FA calculated from images reconstructed by FBP was 2.49±0.47 ml/min/g (2.34∼2.68 ml/min/g) and by microsphere was 2.52±0.19 ml/min/g (2.34 ∼2.68 ml/min/g). In right kidney, the flow by factor analysis was 2.02±0.32 ml/min/g (1.82∼2.49 ml/min/g) and by microsphere was 2.49±0.27 ml/min/g (2.03 ∼2.70 ml/min/g). For RCBF from images reconstructed by OSEM method. RCBF of left kidney was 3.33±0.15 ml/min/g (3.16∼3.47 ml/min/g) and RCBF of right kidney was 2.51±0.17 ml/min/g (2.10∼2.67 ml/min/g). Although our results were obtained from only 1 dog, RCBF by images reconstructed using OSEM was considerably higher than those obtained by FBP method. Further studies on more dogs are required to validate these results