Validation Of A Dynamic PET Simulator In Clinical Brain Studies

This work has been undertaken to evaluate the accuracy of 3-D dynamic simulations in neurological imaging protocols with positron emission tomography (PET). We used [18F] uorodopa PET images from a pair of normal brain and Parkinsonian brain. Spatially correlated MR images were segmented into several tissue types and anatomical structures. Voxels within every structure were assigned with the time activity curves (TACs) derived from clinical studies after correcting for partial volume e ects. Both noisefree and noisy projection data of this brain model were created and reconstructed as in the real scans. TACs were then generated from the dynamic images and compared with the measured data. The results show good agreement between the simulated and observed TACs in the normal brain. However the match is poorer in the Parkinson's brain particularly in striatal structures. This suggests a possible mismatch between the simulated true activity distribution and that in the diseased brain. Both normal and patient data have root-mean-square errors of 2% in cortical gray matter and <10% in striatum without and with noise. This tool can be used to optimize temporal sampling strategy and parameter estimation algorithms. 2