Comparison of clinical data sets acquired on different tomographs using 6-[sup 18] F-l-dopa.

Abstract. Longitudinal positron emission tomography (PET) studies of 6-[sup 18]F-L-dopa uptake in the striatum are used to assess the progression of Parkinson's disease or the survival of neuronal cells grafted in parkinsonian patients. These studies are performed over several years, and data analysis may suffer from the change from old tomographs to new machines with better sensitivity and spatial resolution. Furthermore, such studies on parkinsonian patients may be accomplished in either 2D or 3D acquisition mode. The aforementioned improvements offer great benefits for the study of neurodegenerative diseases, especially those affecting the striatum. However, direct comparison of data is not straightforward owing to variation in scanner characteristics. In this study, we assessed the feasibility of comparing the 6-[sup 18]F-L-dopa striatal uptake values (K[sub c]) measured in two groups of healthy subjects using two tomographs of different generations. We re-studied and compared acquisitions performed on 14 healthy subjects using 6-[sup 18]F-L-dopa. Half of these studies had been performed in 2D acquisition mode using an ECAT 953B. The other half had been performed in 3D acquisition mode using an ECAT EXACT HR+. Different reconstruction protocols were used and the K[sub c] values obtained were statistically compared. The results showed that lowering the transverse spatial resolution of images obtained with the scanner having the better spatial resolution, so that it more closely matched that of the other... [ABSTRACT FROM AUTHOR]