Evaluation of a commercial PET tomograph-based system for the quantitative assessment of rCBF, rOEF and rCMRO2 by using sequential administration of 15O-labeled compounds

The purpose of this study was to develop a reliable and practical strategy that generates quantitative CBF and OEF maps accurately from PET data sets obtained with O-15-tracers. Sequential sinogram data sets were acquired after the administration of O-15-tracers, and combined single-frame images were obtained. The de lay time between sampled input function and the brain was estimated from the (H2O)-O-15 study with the whole brain and the arterial time-activity curves (TACs). The whole-brain TACs were obtained from the reconstructed images (image-base method) and the sinogram data (sinogram-base method). Six methods were also evaluated for the dead-time and decay correction procedures in the process of generating a single-frame image from the dynamic sinogram. The estimated delay values were similar with both the sinogram-based and image-based methods. A lumped correction factor to a previously added single-frame sinogram caused an underestimation of CBF, OEF and CMRO2 by 16% at maximum, as compared with the correction procedure for a short sinogram. This suggested the need for a dynamic acquisition of a sinogram with a short interval. The proposed strategy provided an accurate quantification of CBF and OEF by PET with O-15-tracers.