Quantitation of clinical 3D PET studies with the ETM scatter correction

This work compares the results of clinical studies (a H/sub 2//sup 15/O study with three stimulations, 2 measurements of the [/sup 18/F]fluorodopa uptake in the striata and a cerebral [/sup 18/F]FDG study) acquired on an ECAT 953B in the 3D mode without and with the estimation of true method (ETM) for scatter correction. Results obtained in 3D have been compared to those measured in 2D mode for the same volunteers. The results of the H/sub 2//sup 15/O study performed on one subject with a single activation, show that, with the ETM correction, higher activation signal are measured in 3D than in 2D. For dynamic studies such as [/sup 18/F]Fluorodopa measurements, the ETM allows one to recover quantitative values of the tracer uptake comparable to those obtained in 2D. The measure of the [/sup 18/F]FDG metabolism rate in 3D addresses the problem of an absolute image calibration.