Analytical modeling of PET imaging with correlated functional and structural images

Objective evaluation of dynamic imaging protocols needs a realistic simulation tool to model the data acquisition and image reconstruction of a PET system. Availability of correlated functional and anatomical images in many centers allows the creation of highly realistic objects to represent brain activity and attenuation distribution for each study. The authors have developed an analytical model incorporating key physical factors inherent in coincidence detection along with spatially variant 3-D detector response and detection efficiency. Here, they use MR and PET data of a 3-D Hoffman brain phantom to demonstrate and validate their simulation methods. The simulated total projection, attenuation factor, and scatter profiles are in excellent agreement with the experimental measurements. Regional analysis shows a discrepancy of /spl les/8.5% in the gray matter and white matter activity concentrations between the real and simulated images. The authors' results also reveal quantitative distortions due to partial volume effects with the same magnitude as in clinical PET scans. This tool is particularly useful in evaluating projection data processing and image reconstruction algorithms.